JPH0773970B2 - Suspension pressure controller - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention (Field of Industrial Application) The present invention relates to pressure control of a vehicle suspension, and in particular,
The present invention relates to a device for controlling suspension pressure so as to suppress changes in vehicle body posture due to changes in vehicle operating conditions.

(Prior Art) For example, in Japanese Utility Model Publication No. 62-38402, the steering angular velocity is detected by a sensor, and when the vehicle speed is equal to or higher than a set value and the steering angular velocity is equal to or higher than the set value, the damping force or spring force of the suspension is increased. Suspension pressure control has been proposed.

Further, for example, in Japanese Patent Laid-Open No. 63-106133, the turning pattern of the vehicle is determined from the steering angle and the steering angular velocity, the gain is changed correspondingly, and the gain and the lateral acceleration of the vehicle are dealt with. It has been proposed to control the suspension pressure at the time of turning to determine the suspension pressure.

(Problems to be Solved by the Invention) In these pressure controls, reading (sampling) of detection values of a vehicle speed sensor, a vehicle height sensor, a steering angular velocity sensor, a longitudinal acceleration sensor, a lateral acceleration sensor, and the like, and a differential value based on the read value , The calculation of the integrated value and the like, and the correction of the suspension pressure based on the read value and the calculated value are performed in a constant cycle (sampling cycle).

That is, the state of the sensor or the like and the detected value are read into the CPU (microprocessor) at regular intervals. Each time one reading is completed, the differential value, the integral value, etc. are calculated from the read value, and the required parameters including the read value are adjusted to determine the vehicle running state and body posture, and the suspension is correspondingly adjusted. A pressure (or damping pressure) correction amount is calculated, and this correction is applied to the suspension pressure or damping force.

By the way, the variety of vehicle operating conditions (including road surface conditions and disturbances such as wind) related to changes in vehicle attitude is extremely wide, and the vehicle is stopped (stationary) and has high stability. There is a spread of extremely unstable and rapid changes such as. Therefore, when the vehicle is stopped (stationary), a relatively gentle speed (long sampling period) is sufficient for the suspension pressure correction. However, for example, in the case of high-speed running and sudden steering, the body posture changes such as warp and roll occur on the body, and this change is fast, so if the suspension pressure correction is not as fast as possible (with a short sampling period), the suspension Pressure correction cannot keep up with body posture changes. Note that the warp is a twisting phenomenon around the front-rear direction axis of the vehicle body that occurs between the front wheel portion and the rear wheel portion of the wheel when the vehicle is turning. Means the difference. Generally, the warp amount is represented by the deviation between the left-right vehicle height difference of the front wheel portion and the left-right vehicle height difference of the rear wheel portion. This warp occurs because the roll rigidity of the front wheel portion of the vehicle body is different from the roll rigidity of the rear wheel portion of the vehicle body, and the vehicle body is not a completely rigid body.

Such a problem can be alleviated by predictively detecting the gradual change of the vehicle body posture based on the detection states and detection values of various sensors, and correspondingly switching the sampling cycle between long and short. However, when set to a long cycle, when the operating state changes between reading timings, the detection is too late, and the detection state and detection value of various sensors indicate a slow change in the vehicle body posture. There is a time delay between the detection of the sudden change and the detection of the sudden change, and the delay before the pressure correction operation corresponding to the sudden change is started. In order to improve this, it suffices to always perform the pressure correction operation in a short cycle. However, in this case, in a state where the stability of the vehicle body posture is high, one sampling cycle (one control cycle) The pressure correction value of is small,
Since the calculation of the pressure correction amount is digital, the pressure increases and decreases by the minimum unit frequently in a short cycle, resulting in a relatively high frequency vibrational operation to the mechanical elements of the pressure control system, and the durability of the mechanical elements. Performance may be deteriorated and oscillating mechanical noise and pressure vibration may be caused. Moreover, the sampling period that avoids the occurrence of such a problem and is capable of constantly completing one cycle of suspension pressure correction calculation and correction output is the same as the response speed required at the time of high-speed running and sudden steering. In contrast, it will be too long.

The present invention performs a suspension pressure correction operation at a speed corresponding to a predicted change speed of a vehicle body posture, and at the same time, changes the suspension pressure at the time when the vehicle body posture changes from a high stability state to a sudden vehicle body posture change state. The purpose is to prevent delay of the correction operation.

[Structure of Invention]

(Means for Solving the Problems) A pressure control device of the present invention is a pressure source (1) for supplying a pressure fluid to a suspension (100 fr) that expands and contracts according to the supplied pressure; a pressure source (1) and a suspension. (100f
pressure control means (80fr) for setting the suspension pressure to the target pressure between r); height detection means (15fr) for detecting the height (DFL) of the vehicle body supported by the suspension (100fr); vehicle traveling speed ( Vs) speed detecting means (25, 17)); acceleration detecting means (16p, 16) for detecting longitudinal acceleration (Pg) and lateral acceleration (Rg) applied to the vehicle body
r); Steering detection means (26, 17) for detecting steering of the steering shaft; Height indication information (H) designating a reference height
instruction means (17) for generating t); speed detection means (25,1)
7), warp fluctuation that causes a warp change, which is a twist change of the vehicle body around the longitudinal axis of the vehicle body, at a predetermined cycle dt based on the detection information of the acceleration detection means (16p, 16r) and the steering detection means (26, 17) Modes for detecting running mode (i = 3,4,5), pitching / rolling fluctuation running mode (i = 4,5,6) that causes pitching / rolling changes, and stable running mode (i = 7,8) Detection means (17);
When the mode detection means (17) detects the stable traveling mode (i = 7,8), the first period (dt × 7,8) larger than dt.
Then, the first pressure correction information (54) for compensating the deviation (HT-DHT) of the height detected by the height detecting means (15fr) with respect to the reference height indicated by the height instruction information (Ht) is derived, Pitching / rolling change running mode is detected (i = 4,5,
6) When is the second cycle of dt or more and the first cycle or less (dt × 4,5,6)
Then, in addition to deriving the first pressure correction information, deriving pressure correction information for compensating for pitching / rolling and deriving the second pressure correction information by adding this to the first pressure correction information,
When the warp fluctuation driving mode is detected (i = 3,4,
5) The third cycle (dt × 3,4,5) that is greater than or equal to dt and less than the first cycle
Then, in addition to deriving the second pressure correction information, calculation means (17) for deriving pressure correction information for compensating for warp and deriving third pressure correction information obtained by adding the pressure correction information to the second pressure correction information.
And an electric biasing means (32, 33) for electrically biasing the pressure control means (80fr) so as to apply the pressure correction indicated by the pressure correction information derived by the calculating means (17) to the suspension;
Equipped with. The symbols in parentheses are the symbols attached to the corresponding elements in the embodiments shown in the drawings and described later or the symbols attached to the corresponding detected and calculated values.

(Operation) According to this, in the dt cycle, the state of the sensor or the like and the detected value are read into the mode detecting means (17), and the mode is determined. Then, in the warp fluctuation traveling mode in which the determined mode causes a warp change in the vehicle body and the posture change is predicted to be rapid, the third cycle (dt × 3,4,5) less than or equal to the first cycle Therefore, in the stable driving mode in which the posture change is predicted to be gentle, the first period (dt ×
7, 8), the calculation means (17) compensates (suppresses) the posture change.
Calculate the pressure correction information to be applied, and the electric biasing means (32, 33)
However, the pressure control means (80fr) is electrically energized so that the pressure correction indicated by the pressure correction information is applied to the suspension.

Therefore, in the warp fluctuation traveling mode, the suspension pressure correction is executed in the short third cycle, and in the stable traveling mode, the suspension pressure correction is executed in the long first cycle to correspond to the predicted change speed of the vehicle height posture. The suspension pressure correction operation is performed at the speed.

Even when the suspension pressure correction operation in the stable running mode is being performed (until the update calculation timing of the stable running mode is reached), the mode detecting means (17) has a dt cycle shorter than the third cycle and shorter than the first cycle. The state of the sensor etc., the detected value, etc. are read with to determine the mode, and when the mode is switched, the calculation means (17) switches the correction value in response to this and calculates the pressure correction value corresponding to the subsequent mode. The electric biasing means (32, 33) electrically biases the pressure control means (80fr) so as to apply the pressure correction indicated by the pressure correction information to the suspension.

Therefore, the mode update delay is within dt, and the conventional mode switching delay is greatly shortened. That is, the delay of the suspension pressure correction operation at the time of changing from the state where the vehicle body posture is highly stable to the state where the vehicle body posture changes abruptly is reduced.

Other objects and features of the present invention will become apparent from the following description of embodiments with reference to the drawings.

(Embodiment) FIG. 1 shows an outline of the mechanism of a vehicle body support device. The hydraulic pump 1, which is a radial pump, is disposed in the engine room, is driven to rotate by an engine (not shown) on the vehicle, sucks oil from the reservoir 2, and rotates at a rotation speed higher than a predetermined level to generate a high pressure port 3. The oil is discharged at a predetermined flow rate.

High pressure port 3 of radial pump for suspension pressure
A pulsation absorbing accumulator 4, a main check valve 50, and a relief valve 60m are connected to the high pressure supply pipe 8, and the high pressure oil of the high pressure port 3 is supplied to the high pressure supply pipe 8 through the main check valve 50.

In the main check valve 50, the high pressure port 3 has a high pressure supply pipe 8
When the pressure is lower than the pressure of 1, the reverse flow of oil from the high pressure supply pipe 8 to the high pressure port 3 is blocked.

When the pressure of the high pressure port 3 becomes equal to or higher than a predetermined pressure, the relief valve 60m causes the high pressure port 3 to flow through the reservoir return pipe 11 which is one of the return oil passages to the reservoir 2 so that the pressure of the high pressure port 3 is substantially reduced. Maintain a constant upper pressure.

The high pressure supply pipe 8 is connected to a front wheel high pressure supply pipe 6 for supplying high pressure to the front wheel suspensions 100f _L and 100fr and a rear wheel high pressure supply pipe 9 for supplying high pressure to the rear wheel suspensions 100r _L and 100rr. The front wheel high pressure supply pipe 6 has an accumulator 7 (for the front wheels), and the rear wheel high pressure supply pipe 9 has an accumulator 10
(For rear wheels) is in communication.

A pressure control valve 80fr is connected to the front wheel high pressure supply pipe 6 via an oil filter, and the pressure control valve 80fr changes the pressure of the front wheel high pressure supply pipe 6 (hereinafter referred to as front wheel line pressure) to a required pressure (electricity thereof). The pressure corresponding to the current value of the coil: suspension suspension pressure) is adjusted (reduced) and applied to the cut valve 70fr and the relief valve 60fr.

The cut valve 70fr is provided with the output port 84 (to the suspension) of the pressure control valve 80fr and the suspension 100f when the pressure of the front wheel high pressure supply pipe 6 (front wheel side line pressure) is lower than a predetermined low pressure.
r shock absorber 101fr hollow piston rod 102f
to prevent the pressure from escaping from the piston rod 102fr (shock absorber 101fr) to the pressure control valve 80fr, and the output pressure of the pressure control valve 80fr is maintained while the front wheel side line pressure is equal to or higher than a predetermined low pressure. (Suspension support pressure) is directly supplied to the piston rod 102fr.

The relief valve 60fr limits the internal pressure of the shock absorber 101fr to the upper limit value or less. That is, the pressure control valve 80fr
When the pressure of the output port 84 (suspension supporting pressure) exceeds a predetermined high pressure, the output port 84
As a flow, the pressure at the output port of the pressure control valve 80fr is maintained substantially below a predetermined high pressure.

Further, the relief valve 60fr serves to buffer the propagation of this impact to the pressure control valve 80fr when the internal pressure of the shock absorber 101fr rises due to the impact of pushing up the front right wheel from the road surface, and the shock absorber 101fr. When the internal pressure of the shock absorber rises, the internal pressure of the shock absorber 101fr is discharged to the reservoir return pipe 11 via the piston rod 100fr and the cut valve.

Suspension 100fr is generally a shock absorber 1
It is composed of 01fr and a suspension coil spring 119fr, and is supplied into the shock absorber 101fr via the output port 84 of the pressure control valve 80fr and the piston rod 102fr (pressure regulated by the pressure control valve 80fr: The vehicle body is supported at a height (relative to the front right wheel) corresponding to the suspension support pressure.

The support pressure applied to the shock absorber 101fr is detected by the pressure sensor 13fr, and the pressure sensor 13fr generates an analog signal indicating the detected support pressure.

The vehicle height sensor 15f is located near the suspension 100fr.
r is mounted, and the link connected to the rotor of the vehicle height sensor 15fr is connected to the front right wheel.

The vehicle height sensor 15fr generates an electric signal (digital data) indicating the vehicle height of the front right wheel portion (height of the vehicle body with respect to the wheel).

Similar to the above, pressure control valve 80f _L , cut valve 70f _L , relief valve 60f _L , vehicle height sensor 15f _L and pressure sensor 13
Similarly, f _L is assigned to the suspension 100f _L on the front left wheel portion, and the pressure control valve 80f _L is connected to the front wheel high pressure supply pipe 6 to provide a required pressure (supporting pressure) to the suspension 100f _L. Shock absorber 101f _L piston rod
Give to 102f _L.

Similar to the above, pressure control valve 80rr, cut valve 70rr, relief valve 60rr, vehicle height sensor 15rr and pressure sensor 13rr
Is similarly assigned to the suspension 100rr of the rear right wheel, and the pressure control valve 80rr is connected to the rear wheel high pressure supply pipe 9 to provide a required pressure (support pressure) to the shock absorber 101rr of the suspension 100rr. Piston rod 10
Give to 2rr.

Furthermore, pressure control valve 80r _L and cut valve 70 similar to the above
r _L, relief valve 60r _L, height sensors 15r _L and the pressure sensor 13r _L is likewise suspension of the front left wheel portion 100r
_The pressure control valve 80r _L is connected to the rear wheel high pressure supply pipe 9 to provide a required pressure (supporting pressure) to the piston rod 102r _L of the shock absorber 101r _L of the suspension 100r _L.

In this embodiment, the engine is mounted on the front wheel side,
Along with this, the hydraulic pump 1 is located on the front wheel side (engine room).
Equipped with hydraulic pump 1 to rear wheel suspension 10
The pipe length up to 0rr, 100r _L is longer than the pipe length from the hydraulic pump 1 to the front wheel side suspension 100fr, 100f _L. Therefore, the pressure drop due to the pipe line is large on the rear wheel side, and if oil leakage occurs in the pipe, the pressure drop on the rear wheel side is the largest. Therefore, a pressure sensor 13rm for line pressure detection is connected to the rear wheel high pressure supply pipe 9. On the other hand, the pressure in the reservoir return pipe 11 is lowest at the end on the reservoir 2 side, and tends to increase as the distance from the reservoir 2 increases. I'm trying to detect.

A bypass valve 120 is connected to the rear wheel high pressure supply pipe 9. The bypass valve 120 regulates the pressure of the high pressure supply pipe 8 (obtains a required line pressure) to a pressure corresponding to the value of the electric current flowing through the electric coil. Further, when the ignition switch is opened (engine stop: pump 1 stop), the line pressure is set to substantially zero (the atmospheric pressure of the reservoir 2 through the reservoir return pipe 11) (this line pressure decrease causes the cut valve 70fr , 70f _L , 70rr, 70r _L are turned off to prevent pressure loss of the shock absorber, and reduce the load when restarting the engine (pump 1).

Fig. 2 shows an enlarged vertical section of the suspension 100fr.
A piston 103 fixed to a piston rod 102fr of the shock absorber 101fr roughly divides the inner cylinder 104 into an upper chamber 105 and a lower chamber 106. Suspension supporting pressure (hydraulic pressure) is supplied to the piston rod 102fr from the output port of the cut valve 70fr, and this pressure is applied to the piston rod 102fr.
Join the upper chamber 105 in the inner cylinder 104 through the fr side port 107,
Further, it joins the lower chamber 106 through the vertical through hole 108 of the piston 103. A supporting pressure proportional to the product of this pressure and the cross-sectional area of the piston rod 102fr (square of rod radius × π) is applied to the piston rod 102fr.

The lower chamber 106 of the inner cylinder 104 communicates with the lower space 110 of the damping valve device 109. The upper space of the damping valve device 109 is divided into a lower chamber 112 and an upper chamber 113 by a piston 111, and the oil in the lower space 110 flows through the lower chamber 112 through the damping valve device 109.
High pressure gas is enclosed in 113.

As the front right wheel pushes up, the piston rod
When 102fr suddenly tries to enter below the inner cylinder 104, the internal pressure of the inner cylinder 104 suddenly rises, and similarly the pressure of the lower space 110 tends to suddenly become higher than the pressure of the lower chamber 112. At this time, the damping valve device 109 allows the oil to flow from the lower space 110 to the lower chamber 112 at a predetermined pressure difference or more, but prevents the oil from flowing in the reverse direction. To the lower chamber 112, whereby the piston 111 rises and buffers the impact (upward) applied from the wheel to the piston rod 102fr. That is, the propagation of the wheel impact (upward thrust) to the vehicle body is buffered.

When the piston rod 102fr relatively tries to come out above the inner cylinder 104 due to the sudden fall of the front right wheel, the inner cylinder 10
The internal pressure of 4 suddenly decreases, and similarly the pressure of the lower space 110 tends to suddenly become lower than the pressure of the lower chamber 112. At this time,
The lower space from the lower chamber 112 above the predetermined pressure difference of the damping valve device 109
Oil is allowed to flow to 110, but oil is allowed to flow from the lower chamber 112 to the lower space 110 via a check valve that blocks reverse flow, which causes the piston 111 to descend and the impact applied from the wheels ( (Downward) to the propagation to the piston rod 102fr. That is, the propagation of the wheel impact (falling down) to the vehicle body is buffered.

In addition, shock absorber 101fr
As the pressure applied to the cylinder rises, the pressure in the lower chamber 112 rises, the piston 111 rises, and the piston 111 comes to a position corresponding to the vehicle body load.

When there is no vertical movement of the piston rod 102fr relative to the inner cylinder 104, such as during parking, the seal between the inner cylinder 104 and the piston rod 102fr substantially prevents oil from leaking from the inner cylinder 104 into the outer cylinder 114. There is no. But the piston rod
In order to reduce the vertical movement load of 102fr, the seal is supposed to have a sealing characteristic such that a slight oil leak occurs when the piston rod 102fr moves up and down. The oil that has leaked to the outer cylinder 114 is returned to the reservoir 2 through the outer cylinder 114, the drain 14fr (see FIG. 1) that is open to the atmosphere, and the drain return pipe 12 (see FIG. 1) that is the second return pipe. The reservoir 2 is equipped with a level sensor 28 (Fig. 1),
Generates a signal (oil shortage signal) indicating this when the oil level in the reservoir 2 is equal to or lower than the lower limit value.

Other suspension 100f _L , 100rr and 100r _L structure,
The structure is substantially the same as that of the suspension 100fr described above.

FIG. 3 shows an enlarged vertical cross section of the pressure control valve 80fr. The sleeve 81 has a spool accommodating hole formed in the center thereof, and a ring-shaped groove 83 communicating with the line pressure port 82 and a ring-shaped groove 86 communicating with the low pressure port 85 are formed on the inner surface of the spool accommodating hole. Has been done. These ring-shaped grooves 83
Output port 84 is open in the middle between and 86. Spool 90 inserted in the spool storage hole, in the middle of its side peripheral surface,
A ring-shaped groove 91 having a width corresponding to the distance between the right edge of the groove 83 and the left edge of the groove 86 is provided. A valve housing hole is formed at the left end of the spool 90, and the valve housing hole communicates with the groove 91. The valve body 93 pushed by the compression coil spring 92 is inserted into the valve housing hole. This valve body 93 has a through orifice in the center, and this orifice communicates the space of the groove 91 (output port 84) with the space accommodating the valve body 93 and the compression coil spring 92. Therefore, the spool 90 receives the pressure of the output port 84 (regulated pressure on the suspension 100fr) at the left end thereof, and thereby receives the force that is driven to the right. Note that when the pressure of the output port 84 becomes shockingly high, this causes the valve body 93 to move to the left against the pushing force of the compression coil spring 92, creating a buffer space at the right end of the valve body 93. When the output port 84 is shockedly raised, this shocked rising pressure is not immediately applied to the left end surface of the spool 90, and the valve body 93 is
Spool 90 against shocking pressure increase at output port 84
The effect of buffering the right movement of On the contrary, it exerts a function of buffering the leftward movement of the spool 90 against the shocking pressure drop of the output port 84.

The pressure of the target pressure space 88 communicating with the high pressure port 87 via the orifice 88f is applied to the right end surface of the spool 90, and this pressure causes the spool 90 to receive a force to be driven to the left. The line pressure is supplied to the high-pressure port 87, but the target pressure space 88 communicates with the low-pressure port 89 through the flow passage 94, and the passage opening of the flow passage 94 is defined by the needle valve 95.
When the needle valve 95 closes the flow path 94, the orifice 88
The pressure of the target pressure space 88 communicating with the high pressure port 87 via f becomes the pressure (line pressure) of the high pressure port 87,
90 is driven to the left, so that the groove 91 of the spool 90 communicates with the groove 83 (line pressure port 82), and the groove 91 (output port
The pressure of 84) rises and this is transmitted to the left side of the valve body 93, and the right driving force is given to the left end of the spool 90. When the needle valve 95 fully opens the flow path 94, the pressure in the target pressure space 88 is
Since it is throttled by the orifice 88f, it is significantly lower than the pressure (line pressure) of the high pressure port 87, and the spool 90 moves to the right, whereby the groove 91 of the spool 90 communicates with the groove 86 (low pressure port 85). The pressure in the groove 91 (output port 84) is reduced, and this is transmitted to the left side of the valve body 93, and the right driving force at the left end of the spool 90 is reduced. In this way, the spool 90
This is a position where the pressure in the target pressure space 80 and the pressure in the output port 84 are balanced. That is, a pressure that is substantially proportional to the pressure in the target pressure space 88 appears at the output port 84.

The pressure in the target pressure space 88 is determined by the position of the needle valve 95, and since this pressure is substantially inversely proportional to the distance of the needle valve 95 with respect to the flow path 94, the output port 84 eventually has a substantial distance to the distance of the needle valve 95. Inversely proportional pressure appears.

The needle valve 95 penetrates the fixed core 96 made of a magnetic material. The right end of the fixed core 96 is frustoconical, and the end face of the magnetic plunger 97 having a bottomed conical hole faces the right end face. The needle valve 95 is fixed to the plunger 97. The fixed core 96 and the plunger 97 enter inside the bobbin around which the electric coil 99 is wound.

When the electric coil 99 is energized, magnetic flux flows in the loop of the fixed core 96-magnetic material yoke 98a-magnetic material end plate 98b-plunger 97-fixed core 96, and the plunger 97 is attracted to the fixed core 96 and moves to the left. Then, the needle valve 95 approaches the flow path 94 (the distance becomes shorter). By the way, the left end of the needle valve 95 receives the pressure of the target pressure space 88 as a right driving force,
Since the right end of the is the atmospheric pressure through the low pressure port 98c of the atmosphere release, the needle valve 95, due to the pressure of the target pressure space 88, the right driving force corresponding to its pressure value (which corresponds to the position of the needle valve 95). In the end, the needle valve 95 is connected to the flow path 94.
On the other hand, the distance is substantially inversely proportional to the current value of the electric coil 99. In order to make the relationship between the current value and the distance linear, as described above, one of the fixed core and the plunger has a truncated cone shape, and the other has a bottomed conical hole shape corresponding thereto.

As a result, a pressure that is substantially proportional to the value of the current flowing through the electric coil 99 appears at the output port 84. This pressure control valve
The 80fr outputs a pressure proportional to the energizing current within a predetermined range to the output port 84.

FIG. 4 shows an enlarged vertical cross section of the cut valve 70fr. The valve housing hole formed in the valve base 71 has a line pressure port 72, a pressure adjustment input port 73, an oil drain port 74 and an output port.
75 are in communication. Line pressure port 72 and pressure adjustment input port
The space 73 is separated by a ring-shaped first guide 76, and the space between the pressure adjusting input port 73 and the output port 75 is a cylindrical guide 77a, 77.
Separated by b and 77c. The oil drain port 74 communicates with the ring-shaped groove on the outer periphery of the second guide 77c, and the second guide 77a,
The oil leaked to the outer circumferences of 7b and 77c is returned to the return line 11.

A spool 78 pushed to the left by a compression coil spring 79 passes through the first and second guides 76, 77a to 77c, and a line pressure is applied to the left end surface of the spool 78. The guide hole of the central protrusion of the second guide 77c, into which the left end of the spool 78 has entered,
Ring-shaped groove on the outer periphery of the second guide 77c and the oil drain port 7
It communicates with the return pipe 11 through 4. When the line pressure is less than a predetermined low pressure, as shown in FIG. 4, the spool 78 is driven to the leftmost side by the repulsive force of the compression coil spring 79, and the spool is provided between the output port 75 and the pressure adjusting input port 73.
78 is blocked by fully closing the inner opening of the second guide 77a. When the line pressure becomes equal to or higher than a predetermined low pressure, the spool 79 starts to be driven rightward against the repulsive force of the compression coil spring 79 by this pressure, and the spool 79 is located at the rightmost position (fully opened) at a pressure higher than the predetermined low pressure. . That is, when the spool 78 moves to the right of the inner opening of the second guide 77a, the pressure adjusting input port 73 communicates with the output port 75, and the line pressure (line pressure port 72) rises to a predetermined low pressure, the cut valve 70fr becomes , Pressure adjusting input port 73 (pressure control valve 80
fr pressure output) and output port 75 (shock absorber 10)
1 fr) and the line pressure (port 72) rises further, pressure regulating input port 73 (pressure regulating output of pressure control valve 80 fr) and output port 75 (shock absorber 101 fr)
Fully open between. When the line pressure decreases, the reverse occurs. When the line pressure becomes less than the predetermined low pressure, the output port 75 (shock absorber 101fr) is turned on by the pressure adjusting input port 7
Completely cut off from 3 (pressure control output of pressure control valve 80fr).

FIG. 5 shows an enlarged vertical cross section of the relief valve 60fr. An input port 62 and a low pressure port 63 are opened in the valve housing hole of the valve base 61. The valve housing hole has a cylindrical first
Guide 64 and second guide 67 are inserted, and input port
The filter 62 communicates with the inner space of the first guide 64 through the filter 65. A valve body 66 having an orifice at its center is inserted into the first guide 64, and the valve body 66 is pushed to the left by a compression coil spring 66a. First guide 6
The space of 4 in which the valve body 66 and the compression coil spring 66a are housed communicates with the input port 62 through the orifice of the valve body 66, and through the opening of the spring seat 66b.
It communicates with the inner space of the guide 67. The conical valve body 68 is pushed to the left by the repulsive force of the compression coil spring 69, and
The opening of 66b is closed. When the pressure (control pressure) of the input port 62 is less than the predetermined high pressure, the coil spring 66 communicating with the input port 62 through the orifice of the valve body 66.
Since the pressure in the storage space is relatively lower than the repulsive force of the compression coil spring 69, the valve body 68 closes the central opening of the valve seat 66b as shown in FIG. 62 is cut off from the inner space of the second guide 67, which communicates with the low pressure port 63 through the hole 67a. That is, the output port 62 is cut off from the low pressure port 63.

When the pressure (control pressure) of the input port 62 rises to a predetermined high pressure, this pressure is applied to the central opening of the valve seat 66b through the orifice of the valve body 66, the valve body 68 starts to be driven right by this pressure, and the input port 62 When the pressure further rises, the valve element 68 is driven to the right. That is, the pressure at the input port 62 is
It is discharged to the low pressure port 63, and the control pressure is suppressed below a predetermined high pressure.

If a high pressure is applied to the input port 62 due to shock, the valve body 66
Is driven to the right and the input port 62 is moved to the side opening 64 of the first guide 64.
It communicates with the valve storage space of the base body 61 through a and communicates with the low pressure port 63. Since this flow passage area is large, the output port
The sudden pressure rise (pressure shock) of 62 is buffered.

FIG. 6 shows an enlarged vertical cross section of the main check valve 50. An input port 52 and an output port 53 communicate with the valve housing hole formed in the valve base body 51. A cylindrical valve seat 54 with a bottom is housed in the valve housing hole, and a flow valve 55 of the valve seat 54 is pressed by a compression coil spring 56 to a ball valve 57.
Is closed, but when the pressure at the input port 52 is higher than the pressure at the output port 53, the ball valve 57 is pushed to the right by the pressure at the input port 52 to open the passage port 55. Ie input port
Oil flows from 52 to the output port 53. However, when the pressure at the output port 53 is higher than the pressure at the input port 52, the ball valve 57 closes the flow port, so that oil does not flow from the output port 53 toward the input port 52.

FIG. 7 shows an enlarged vertical cross section of the bypass valve 120. The input port 121 communicates with the inner space of the first guide 123, and the valve body 124a pushed leftward by the compression coil spring 124b is housed in the inner space. The valve body 124a has an orifice at the center of the left end face, and the input port 121 communicates with the inner space of the first guide 123 through this orifice. The internal space communicates with the low pressure port 122 through the flow path 122b, and the flow path 122b is opened and closed by the needle valve 125.

The solenoid device composed of the needle valve 125 to the electric coil 129 has the same structure and the same size as the solenoid device composed of the needle valve 95 to the electric coil 99 shown in FIG. 3 (designed commonly for the pressure control valve and the bypass valve). And the orifice 12
The distance of the needle valve 125 with respect to 2b is substantially inversely proportional to the value of the current flowing through the electric coil 129. Since the flow opening of the orifice 122b is inversely proportional to this distance, the oil flow rate from the input port 121, through the orifice of the valve element 124a, through the inner space of the first guide 123, through the orifice 122b, and out to the low pressure port 122 is , Is proportional to the differential pressure across the orifice on the left end surface of the valve body 124a.

As a result, the pressure at the input port 121 becomes a pressure that is substantially proportional to the value of the electric current flowing through the electric coil 129. The bypass valve 120 sets the pressure (line pressure) of the input port 121 to a pressure proportional to the pressure of the energizing current within a predetermined range. When the ignition switch is off (engine stop: pump 1 stop), the electric coil 129 is de-energized to move the needle valve 125 to the right and the input port 121 (line pressure) to the return pressure. It becomes a low pressure near.

When the pressure of the input port 121 rises explosively, the valve body 124a is driven rightward by receiving this pressure on the left end face,
The low pressure port 122a, which communicates with the low pressure port 122, communicates with the input port 121. Since the low pressure port 122a is a relatively large opening, the shocking rising pressure of the input port 21 immediately escapes to the low pressure port 122a.

The relief valve 60m has the same structure as the relief valve 60fr described above, but has a conical valve body (68: Fig. 5).
The compression coil spring (69) that presses is made to have a slightly small spring force, and the pressure of the input port (62) (pressure of the high pressure port 3) and the relief valve 60fr change the pressure of the input port 62 to the low pressure port. The output port (62) is blocked from the low pressure port (63) when the pressure is less than a predetermined high pressure, which is slightly lower than the pressure discharged to 63. When the pressure of the input port (62) becomes higher than a predetermined high pressure, the valve disc (6
8) is driven to the far right. That is, the input port (6
The pressure of 2) is discharged to the low pressure port (63), and the pressure of the high pressure port 3 is suppressed below a predetermined high pressure.

With the structure described above, in the vehicle body support device shown in FIG. 1, the main check valve 50 supplies oil from the high pressure port 3 to the high pressure supply pipe 8, but prevents backflow from the high pressure supply pipe 8 to the high pressure port 3. To do.

The relief valve 60m suppresses the pressure of the high pressure port 3, that is, the pressure of the high pressure supply pipe 8 to a predetermined high pressure or less,
When the pressure of the shock absorber rises, it is released to the return pipe 11 to buffer the shock pressure transmission to the high pressure supply pipe 8.

The bypass valve 120 controls the pressure of the rear wheel high pressure supply pipe 9 substantially linearly within a predetermined range, and maintains the pressure of the rear wheel high pressure supply pipe 9 at a predetermined constant pressure in a steady state. This constant pressure control is performed by controlling the energizing current value of the bypass valve 120 with reference to the pressure detected by the pressure sensor 13rm. Also, when there is a shocking pressure increase in the rear wheel suspension,
It escapes to the return pipe 11 and buffers the propagation to the high pressure supply pipe 8. Furthermore, when the ignition switch is open (engine stopped: pump 1 stopped), the power supply is cut off,
The rear wheel high pressure supply pipe 9 is passed through the return pipe 11 to release the pressure of the rear wheel high pressure supply pipe 9 (high pressure supply pipe 8).

The pressure control valves 80fr, 80f _L , 80rr, 80r _L output the required supporting pressure by controlling the energizing current value of the electric coil (99) so that the suspension pressure control gives the required supporting pressure to the suspension. Output to port (84). When the shock pressure from the suspension propagates to the output port (84), it is buffered and the spool (91) for pressure control is used.
Suppresses turbulence (turbulence in output pressure). That is, the required pressure is stably applied to the suspension.

The cut valves 70fr, 70f _L , 70rr, 70r _L are provided for the suspension pressure supply line (the pressure control valve output port 84 and the suspension when the line pressure (front wheel high pressure supply pipe 6, rear wheel high pressure supply pipe 9) is lower than a predetermined low pressure. Between) to prevent the pressure from escaping from the suspension and fully open the pressure supply line when the line pressure is equal to or higher than a predetermined low pressure. This allows
An abnormal drop in suspension pressure when the line pressure is low is automatically prevented.

The relief valves 60fr, 60f _L , 60rr, 60r _L limit the pressure (mainly suspension pressure) in the suspension pressure line (between the output port 84 of the pressure control valve and the suspension) to below the high pressure upper limit value to prevent wheel collision. When there is a shocking pressure increase in the pressure supply line (suspension) due to lifting or throwing when mounting a heavy object, this is released to the return pipe 11 to mitigate the shock of the suspension and hydraulic line connected to the suspension. And increase the durability of the mechanical elements connected to it.

FIG. 8 shows the operating conditions, postures, etc. of the vehicle in accordance with the states of various switches and sensors mounted on the vehicle, and the corresponding pressures required for each suspension shown in FIG. An outline of the configuration of an electric control system for setting a desired value is shown.

A low-pass filter 31 ₁ is connected to the vehicle height sensors 15f _L , 15fr, 15r _L and 15rr described above, and the low-pass filter 31 _1
1 cuts off high frequency (noise) components of the vehicle height detection signals (analog signals) of the vehicle height sensors and smoothes vibration components having a relatively high frequency, and amplifies the vehicle height signals shaped in this way. 30 ₁ amplifies it to a predetermined level range and supplies it to the A / D converter (IC) 29 ₁ .

Pressure sensors 13f _L and 13f that detect the hydraulic pressure of each suspension
r, 13r _L, the 13rr, and the low-pass filter 31 ₂ is connected, the low-pass filter 31 _2, blocks the high frequency (noise) component of each of the pressure detection signal pressure sensor (analog signal), and relatively The high-frequency vibration component is smoothed, and the pressure signal shaped in this way is amplified by the amplifier 30 ₂ to a predetermined level range and given to the A / D converter (IC) 29 ₂ .

Pressure sensor 13rm for detecting the pressure of the rear wheel high pressure supply pipe 9 and pressure sensor 13rt for detecting the pressure of the rear wheel side of the return pipe 11
The low pass filter 31 ₃ are connected, the low-pass filter 31 _3, blocks the high frequency (noise) component of each of the pressure detection signal pressure sensor (analog signal),
Further, the vibration component having a relatively high frequency is smoothed, and the pressure signal shaped in this way is amplified by the amplifier 30 ₃ to a predetermined level range and given to the A / D converter (IC) 29 ₃ .

In addition, the longitudinal acceleration (+:
The vertical acceleration sensor 16p that detects acceleration, −: deceleration) and the lateral acceleration sensor 16r that detects lateral acceleration in the vehicle lateral direction (+: left-to-right acceleration, −: right-to-left acceleration) Low pass filter 31 ₃ is connected,
The low-pass filter 31 _3, blocks the fraction frequency (noise) of the acceleration sensors each pressure detection signal (analog signal), and a frequency of the high vibrational relatively smooth,
The thus shaped acceleration signal is amplified by the amplifier 30 ₃ to a predetermined level range and given to the A / D converter (IC) 29 ₃ .

A coil driver is installed in the electric coil 99 of the pressure control valve 80f _L , 80fr, 80r _L , 80rr and the electric coil 129 of the bypass valve 120.
33 is connected. The coil driver 33 has a switching circuit that energizes each of the electric coils, and a current detection circuit that detects an energization current value of each electric coil and generates an analog signal indicating the current value. The duty controller (IC) 32 ON (energized) / OFF (non-energized)
In response to the instruction, the electric coil and the output terminal of the constant current circuit are made conductive (ON) when the ON instruction is given and cut off when the OFF instruction is given. Then, providing an analog voltage indicating the detected current value at all times A / D converter (IC) 29 _3.

The duty controller 32 stores (latches) the energizing current value designation data given from the microprocessor (hereinafter referred to as CPU) 18 to each of the electric coils (each of the pressure control valve and the bypass valve), and feeds back the detection. From the current value to A / D converter (IC) 29 ₃ CPU18
Is input to the coil driver 33, and the CPU 18 adjusts the on / off duty so that the specified current value is obtained, and gives a time series on / off instruction corresponding to this duty to the coil driver 33.

A / D converters 29 _{1 to} 29 ₃ have four input ports (however, 29 ₃ receives the analog voltage indicating the detected current value of the pressure control valve and the bypass valve from the coil driver 33) This is an A / D conversion IC that has a built-in hold circuit.
When there is a conversion instruction from 18, the analog voltage of the input port is held in the sample hold circuit and converted into digital data (vehicle height data, pressure data, acceleration data), and the digital data is converted into clock pulses given by the CPU 18. Synchronous and serially transferred to the CPU 18. This analog voltage hold, digital conversion, and digital data transfer are sequentially performed for the input ports 1 to 4. That is, when the CPU 18 once instructs the A / D conversion, the analog voltages of the four input ports are sequentially digital-converted and the digital data are sequentially transferred to the CPU 18.

The CPU 18 is connected to the CPU 17 in a data transmission / reception relationship.

The CPU17 has a signal indicating whether the brake pedal is depressed (H) or not (L), and the ignition switch 20 is opened (L).
/ Closed (H) signal, a pulse generated by a vehicle speed synchronizing pulse generator 25 for generating an electric signal of 1 pulse per rotation of the output shaft of the on-vehicle transmission by a predetermined small angle, and the pulse generated by the vehicle speed synchronizing pulse generator 25 is coupled to the steering shaft. The first and second sets of pulses of the rotary encoder 26, which produces a first set of pulses, one pulse per angular rotation, and a second set of pulses that are 90 degrees out of phase, the engine throttle valve. Of the absolute encoder 27 that is connected to the rotary shaft of the engine and generates 3-bit data indicating the throttle valve opening, and the signal of the level sensor 28 that detects the oil level of the reservoir 2 (H: lower limit level or less, L: (A level higher than the lower limit level), and signals from other sensors (not shown) are also provided from the input / output circuit 34.
An indicator such as a warning light is connected to the input / output circuit 34, and when an abnormality is determined in the pressure control of the suspension, the CPU 17 instructs the input / output circuit 34 to display the abnormality.

The vehicle battery 19 has a low-capacity backup power supply circuit.
23 is connected and supplies a constant voltage to the CPU 17, so that the CPU 17 is always in the operating state and holds the data in its internal memory while the voltage of the battery 19 is equal to or higher than a predetermined value.

A high-capacity constant voltage power supply circuit 21 is connected to the on-vehicle battery 19 via an ignition switch 20, and this power supply circuit 21 gives a low constant voltage to a weak electric element and a circuit such as the CPU 18, and a low-pass filter. 31 _{1 to} 31 ₃ and ON /
A high constant voltage is applied to circuits such as the output circuit 34.

To the ignition switch 20, the contact piece of the self-holding relay 22 is connected in parallel, and the relay 22 is turned on (closed).
/ OFF (open) by CPU17.

The CPUs 17 and 18 store programs that control the pressure of each suspension. According to this program, the CPU 18 mainly controls the vehicle height sensors 15f _L , 15fr, 15r _L , 15rr provided in the suspension system shown in FIG.
And pressure sensors 13f _L , 13fr, 13r _L , 13rr, 13rm, 13rt, and the vertical acceleration sensor 16p and lateral acceleration sensor 16r on the vehicle, and the pressure control valves 80f _L , 80fr, 80r.
_L , 80rr and the value of the current flowing through the electric coil (99, 129) of the bypass valve 120 are controlled.

The CPU 17 sets / releases the line pressure of the suspension system (FIG. 1), determines the vehicle operating state, and determines the determination result from when the ignition switch 20 is closed to when the ignition switch 20 is opened. Calculates the required pressure (pressure that should be set for each suspension) required to establish an appropriate vehicle height and body posture, and receives various detected values from the CPU 18 to determine the vehicle operating state and sets the required pressure. The CPU 18 is supplied with the energizing current value required for the operation.

Below, referring to the flowchart shown in FIG.
The control operation of U17 and U18 will be explained.First, for ease of understanding, the symbols assigned to the main registers assigned to the internal memory of CPU17 and the contents of the main data written to each register are described. The summary is shown in Table 1.

In the flow chart of the drawings and the description below, the register symbol itself may mean the contents of the register.

First, refer to FIG. 9a. When the power is supplied to itself (step 1: the backup power supply circuit 23 generates a constant voltage: the battery 19 is mounted on the vehicle body), the CPU 17 causes the internal registers, the counter, the timer, etc. to be in the initial standby state. Set to At the output port, output the signal level for the initial standby state (no electrical energization of each element of the mechanism) (Step 2: In parentheses, words such as step and subroutine are omitted, and symbols attached to them. Only note).

Next, the CPU 17 checks whether the ignition switch 20 is closed (3), and when it is open, waits until it is closed.

When the ignition switch 20 is closed, the coil of the relay 22 is energized to close the contact piece of the self-holding relay 22 (4). When the ignition switch 20 is closed, the high-capacity constant-voltage power supply circuit 21 is connected to the battery 19, and the power supply circuit 21 gives a low constant voltage to the weak electric elements and electric circuits such as the CPU 18, and the high-constant voltage is low-passed. Filter 31 _{1 to} 31 ₃
Since it is given to circuits such as the input / output circuit 34, the CPU1
8 and the like are also electrically energized and are in operation, but when the relay 22 is turned on, the power circuit 21
Since it is connected to the battery 19, even if the ignition switch 20 is opened thereafter, the electric circuit system shown in FIG. 8 is electrically energized until the CPU 17 turns off the relay 22. To maintain the operating state.

When the relay 22 is turned on, the CPU 17 permits the interrupt processing executed in response to the arrival of the pulse signal to the interrupt input ports ASR0 to ASR2 (5).

Here, the outline of the interrupt processing in response to the pulse signal to the input ports ASR0 to ASR2 will be described. First, interrupt processing in response to the pulse generated by the vehicle speed synchronization pulse generator 25 (input port AS
Explaining R2), when the generator 25 generates one pulse,
In response to this, it proceeds to the interrupt process (ASR2), reads the contents of the vehicle speed clock register at that time, restarts the vehicle speed clock register, and calculates the vehicle speed value from the read contents (cycle of vehicle speed synchronization pulse). The value Vs obtained by calculating the weighted average and the vehicle speed calculation value that was held several times before is used as the vehicle speed register VS.
, And returns to the step immediately before proceeding to this interrupt processing (return).

By executing this interrupt processing (ASR2), the vehicle speed register VS
In addition, the data Vs indicating the vehicle speed at that time (the time-series smoothed value of the vehicle speed calculation value) is always held.

The interrupt processing (input port ASR0) of the rotary encoder 36 for detecting the rotation direction of the steering shaft in response to the first set of generated pulses will be described. This interrupt processing is performed at the rising and falling edges of the first set of generated pulses. (ASR0)
When the operation proceeds to the interrupt processing (ASR0) in response to the rising edge, H is written to the flag register for rotation direction discrimination, and when the interrupt processing (ASR0) proceeds in response to the falling edge, the flag register is changed to It clears (writes L) and returns to the step immediately before proceeding to this interrupt processing.

When the rising of the second set of pulses appears after the rising of the first set of pulses (flag register = H) of the rotary encoder 26, the steering shaft is driven to rotate left.

When the trailing edge of the second set of pulses appears after the trailing edge of the first set of pulses (flag register = L), the steering shaft is being driven to rotate clockwise.

Explaining the interrupt processing (input port ASR1) of the rotary encoder 36 for detecting the rotation speed (steering angular velocity) of the steering shaft in response to the generated pulse of the second set, the pulse of the second set (falling edge) is When it arrives, it responds to this and advances to the interrupt processing (ASR1), reads the contents of the steering clock register at that time, and restarts the steering clock register.

Then, in the read contents (cycle of rudder angular velocity synchronization pulse),
When the content of the flag register for discriminating the rotation direction is H, the sign of + (counterclockwise rotation) is set, and the content of the flag register is set to L.
Is added, the sign of − (clockwise rotation) is added, the speed value (including directions + and −) is calculated from that, and the speed calculation value and the weighted average held several times before are calculated. The obtained value Ss is written in the steering angular velocity register SS, and the process returns to the step immediately before proceeding to this interrupt processing (return).

By executing this interrupt processing (ASR1), the steering angular velocity register SS always stores data Ss indicating the steering angular velocity (time-series smoothed value of the speed calculation value) at that time (+ indicates left rotation, − indicates right rotation).
Is held.

When the above-mentioned interrupt processing is permitted, the CPU 17 checks whether the CPU 18 gives a ready signal (6).

By the way, the CPU 18 executes initialization when it is powered on (the ignition switch 20 is closed),
Set the internal registers, counters, timers, etc. to the contents of the initial standby state, and set the output port to the initial standby state (no electrical energization of each element of the mechanism) (the duty controller 32 uses all electrical signals). Outputs data that specifies coil off).

Then, the duty controller 32 is connected to the bypass valve 120.
The maximum current value data for fully closing the valve is given to instruct the bypass valve 120 to be energized. With the above settings, the pressure control valves 80f _L , 80fr, 80r _L , and 80rr have zero energization current value, and the pressure of the return pipe 11 is output to the output port (84) of the pressure control valve, but the bypass valve 120 is fully closed. Since the ignition switch 20 is closed (engine rotation), the pump 1
The rotational pressure of the high pressure supply pipe 8, the front wheel high pressure supply pipe 6 (accumulator 7) and the rear wheel high pressure supply pipe 9 (accumulator 10) starts to increase.

After that, the CPU 18 sets the vehicle height sensors 15f _L , 15f at the first set cycle.
r, 15r _L , 15rr, pressure sensor 13f _L , 13fr, 13r _L , 13rr, 13rm, 13r
When t, the detection value of the vertical acceleration sensor 16p and the lateral acceleration sensor 16r, and the current detection value of the coil driver 33 are read and updated and written in the internal register, and the CPU 17 requests the transfer of the detection data, at that time The data in the internal register of is transferred to the CPU 17. In addition, the CPU 17 controls the pressure control valve 80
When the energizing current value data of f _L , 80fr, 80r _L , 80rr and bypass valve 120 is sent, these are sent to the duty controller.
Give to 32.

By the way, CPU17, in the check of steps 6 and 7 above,
When the CPU 18 is giving a busy signal, it waits there and executes the waiting process (8 to 11).

In the standby process (8), the pressure detection values of all the pressure sensors, the current detection values of all the electric coils of the coil driver 33, and the vehicle height detection values of all the vehicle height sensors are referred to determine whether there is an abnormality and the suspension control waits. When the pressure is set (stopped) (bypass valve 120 is de-energized and fully opened and pressure control valve is de-energized), if an abnormality is determined, notification and pressure setting corresponding to the abnormality (bypass valve 120 de-energized) , The pressure control valve is not energized) (10). If no abnormality is determined, the abnormality processing is canceled (abnormality notification is cleared) (11).

Now, when the CPU 18 notifies the ready, the above-mentioned abnormal processing (which may not be executed) is canceled (12) and the above-mentioned standby processing (which may not be executed) is canceled (1
3).

Then, the CPU 17 instructs the CPU 18 to transfer the detection pressure data Dph of the pressure sensor 13rm, receives it, and writes it in the register DPH (14), and the detection pressure (pressure on the rear wheel of the high pressure supply pipe 8) Dph.
Is checked (whether the line pressure has risen to a certain level) or more (1) to check if it is equal to or higher than a predetermined value Pph (pressure value lower than the predetermined low pressure at which the cut valves 70f _L , 70fr, 70r _L , 70rr start to open).
Five). If the line pressure has not risen, the process returns to step 6.

When the line pressure rises, CPU17 causes CPU18
Detection pressure (initial pressure) data Pf _L0 , Pf of f _L , 13fr, 13r _L , 13rr
It instructs transfer of r ₀ , Pr _L0 , Prr ₀ , receives them, and writes them in registers PFL ₀ , PFR ₀ , PRL ₀ , PRR ₀ (16).

Then, the energizing current value data required to obtain the required pressure in one area (table 1) of the internal ROM is stored in the registers PFL ₀ and PFR.
₀ , PRL ₀ , PRR ₀ contents Pf _L0 , Pfr ₀ , Pr _L0 , Prr ₀ access to output the pressure Pf _L0 to the output port 84 of the pressure control valve 80f _L Value Ihf _L , pressure Pfr ₀
To the pressure control valve 80fr output port Ihfr, pressure Pr _L0 to the pressure control valve 80r _L output port current Ihr _L and pressure Prr ₀ to the pressure control valve The energizing current value Ihrr required to output to the 80 rr output port is read from table 1 and output register
Write (17) to IHf _L , IHFr, IHr _L and IHrr, and transfer the data of these output registers to the CPU 18.

When the CPU 18 receives these data, it gives them to the duty controller 32.

The duty controller 32 uses the energizing current value data Ihf _L , I
The electric coil of the pressure control valve 80f _L is set so that the energizing current value (detection value) of the pressure control valve 80f _L , which is fed back by the CPU 18 by storing (latching) hfr, Ihr _L and Ihrr, becomes Ihf _L.
The ON (energization) / OFF (non-energization) duty of 99 is adjusted, and the time series ON / OFF corresponding to the adjusted duty is adjusted.
An instruction to turn off is given to the coil driver 33 to the pressure control valve 80f _L , and the same duty control is performed to the other pressure control valves 80fr, 80r _L and 80rr, so that the time series on / off is turned on and off. An instruction is given to the coil driver 33.

With such current settings, the pressure control valves 80f _L , 80fr, 80
r _L , 80rr, when the line pressure is a predetermined low pressure or more, the pressures of Pf _L0 , Pfr ₀ , Pr _L0 , Prr ₀ are output port (8
4), and when the cut valves 70f _L , 70fr, 70r _L , 70rr open in response to the line pressure rising above the specified low pressure, the pressure (initial pressure) Pf _L0 , P of each suspension at that time.
When the pressure is substantially equal to fr ₀ , Pr _L0 , Prr ₀ , the cut valves 70f _L , 70
Through fr, 70r _L , 70rr Pressure control valve 80f _L , 80fr, 80r _L , 80rr
Supplied from Suspension 100f _L , 100fr, 100r _L , 100rr.

Therefore, the ignition switch 20 is opened (engine stopped: pump 1 stopped) to closed (pump 1 driven),
When the cut valves 70f _L , 70fr, 70r _L , 70rr are opened for the first time (line pressure is lower than a predetermined low pressure) and the hydraulic line of the suspension communicates with the output port of the pressure control valve, the output pressure of the pressure control valve and the suspension pressure are Are substantially equal to each other, and sudden pressure fluctuations in the suspension do not occur. That is, no shocking change in the vehicle body posture occurs.

The above is the pressure control valve 80f _L , 8 when the ignition switch 20 is switched from open to closed (immediately after starting the engine).
This is the initial output pressure setting of 0fr, 80r _L , 80rr.

Next, the CPU 19 starts a timer dt with a dt (32 msec) time limit.

When the timer dt is started, the CPU 17 reads the state (20). In this case, the open / close signal of the ignition switch 20, the open / close signal of the brake pedal depression detection switch BPS, the throttle opening data of the absolute encoder 27, and the signal of the reservoir level detection switch 28 are read and written in the internal register. To send the detection data to the vehicle height sensor 15f _L , 15fr, 15r _L , 15rr vehicle height detection data Df _L , Dfr, Dr _L , Drr, pressure sensor 13f _L , 13fr,
13r _L , 13rr, 13rm, 13rt pressure detection data Pf _L , Pfr, Pr _L , Pr
r, Prm, Prt, and pressure control valve and bypass valve 80f
_L , 80fr, 80r _L , 80rr, 120 Receives the energization current value detection data and writes it to the internal register. Then, referring to these read values, it is determined whether there is an abnormality or not, and when it is abnormal, the process proceeds to step 8.

When normal, the CPU 17 next executes line pressure control (LPC). In this, the reference pressure (relief valve 60m
The absolute value and polarity (high / low) of the deviation of the detection line pressure Prm from the relief pressure (a fixed value slightly lower than the relief pressure (predetermined high pressure)) are calculated, and the deviation is added to the current value flowing in the bypass valve 120 at present. Then, a correction value for making the deviation zero is added corresponding to the above, the current value of the bypass valve 120 energization current is calculated, and this is written in the output register.

Note that the contents of this output register are as described in step 36 below.
Then, transfer to CPU18.

By this "line pressure control" (LPC), the rear wheel high pressure supply pipe 9
The energizing current value of the bypass valve 120 is controlled so that the pressure of is a predetermined value slightly lower than the relief pressure of the relief valve 60m.

Now referring to FIG. 9b. When the line pressure control (LPC) is completed, the CPU 17 checks whether the switch 20 is open or closed (2
2) If it is open, stop processing (23) is performed, relay 22 is turned off, and interrupts ASR0 to ASR2 are disabled. In the stop process (23), first, the bypass valve
De-energize 120 and fully open (release line pressure to return pipe 11). Switch 20 open (engine stopped: pump 1
Stop), the high pressure discharge of the pump 1 is stopped, and the bypass valve 120 is fully opened, so that the high pressure supply pipe 8, the front wheel high pressure supply pipe 6 (accumulator 7) and the rear wheel high pressure supply pipe 9 (accumulator 10) Becomes the pressure of the return pipe 11,
Since the pressure in the return pipe 11 is released to the reservoir 2,
The high-pressure supply pipe 8 and the like become atmospheric pressure. At the timing when the high pressure supply pipe 8 or the like has reached a pressure lower than a predetermined low pressure at which the cut valves 70f _L , 70fr, 70r _L , 70rr are completely shut off, the CPU 17 sets the pressure control valves 80f _L , 80fr, 80r _L , 80rr. Not energized.

Now, when the switch 20 is closed, the parameter indicating the vehicle traveling state is calculated (25). That is, the content Ss of the steering angular velocity register SS is read, and [the value read this time Ss−
The value read last time] / dt = Sa (steering angular acceleration) is calculated and written in the register SA, and [the throttle opening Tp read this time read by the sub routine 20-throttle opening read last time] = Ts (Throttle opening / closing speed) is calculated and written into the register TS, and [the vertical acceleration Pg read this time, the vertical acceleration read last time−the vertical acceleration read last time] = Pa (change rate of the vertical acceleration) is calculated. To the register PA, calculate [the lateral acceleration Rg read by the subroutine 20, the lateral acceleration Rg read last time-the lateral acceleration read last time] = Ra (rate of change in lateral acceleration), and write it in the register RA.

Next, the CPU 17 controls the rudder angular velocity SS, the throttle opening / closing speed TS, and the vehicle speed V.
The suspension pressure control mode to be executed is determined by referring to S, the opening / closing of the brake pedal depression detection switch BPS, the longitudinal acceleration Pg and the lateral acceleration Rg, and as shown in Table 2, the suspension pressure control mode is determined. To Determine (26-109).

Then, it is checked whether or not the content of the counting target value register N is the same as the suspension pressure control mode (i indicating the execution cycle of) decided this time (110). , I indicating the execution cycle of the control mode determined this time is updated and written (111), the process proceeds to step 115 shown in FIG. 9c, the count value register n is cleared, and the control mode of step 116 and thereafter is executed. . When they are the same, the content of the count value register n is updated to a value that is one larger than that, and the content of the count value register n becomes equal to the content of the count target value register N (it becomes the execution timing of the control mode. ) Is checked (113), and if so, the routine proceeds to step 115 shown in FIG. 9c, the count value register n is cleared, and the control mode from step 116 onward is executed. If n has not reached N, it waits for the timer dt to expire (114) and returns to step 19 in FIG. 9a to restart the timer dt and read the state (20).

By executing steps 26 to 30-101 to 115 described above, it is possible to read the state of the sensor or the like and the detected value into the CPU 17 by d.
The CPU 17 determines the suspension pressure control mode (i indicating the execution period of) to be executed in this period, and the control mode determined this time is the previous (dt
(Previous) When the control mode determined is different, the control mode determined this time is immediately executed (110-111-115-116 or less). When the control mode determined this time is the same as the control mode determined last time, the content of the count value register n is incremented by 1 (112), and n is the content N of the target count value register N (execution cycle target value of the control mode). Check if it is equal to (113) and it is equal (it is the execution timing of the determined control mode)
And execute the control mode that has been decided (110-112-113-
115-116 or less). If n is less than the content N of the target count value register N (it is not the execution timing of the determined control mode), it waits for the timer dt to expire and returns to the state reading (20) (110-112- 113-114-19-20).

From the above, for example, stable driving mode (No. 2 in Table 2)
, And dt (32msec) during continuous judgment in dt cycle
The state of the sensor etc. and the detected value are read in the cycle, and the control mode is determined, and the suspension in the stable running mode (No.2) is executed in the cycle of dt × i (i = 7, so 32 × 7 msec). pressure control (31V ₃ -33-35~37 of the 9c view) is executed. If the control mode to be executed changes to a warp fluctuation running mode (No. 8 in Table 2) at some point,
Therefore, first, the pressure control in the warp fluctuation drive mode
31-37) is executed, and while the mode determination of the dt cycle is the warp fluctuation traveling mode (No.8), the state of the sensor and the like and the detected value are read in the dt cycle, and
Suspension pressure control (No. 8) in warp fluctuation running mode (No. 8) at a cycle of dt x i (32 x 3 msec because i = 3)
31-37) in Fig. 9c is executed.

Go to Suspension Pressure Control (116 in Figure 9c)
17 is the contents of the target count value register N (this is the same as i)
Check the determined control mode by referring to
When N is 3 or less (No. 8 in Table 2: Warp fluctuation running mode), "Vehicle height deviation calculation 1" (31), "Pitching /
Rolling prediction calculation 1 "(32)," Calculation of target pressure "(3
3), "Warp correction 1" (34), "Pressure correction" (35),
"Pressure / current conversion" (36) and "output" (37) are executed in this order.

In "vehicle height deviation calculation 1" (31), the CPU 17 calculates the suspension pressure correction amount (first correction amount: for each suspension) required to calculate the deviation of the detected vehicle height from the reference vehicle height and set it to zero. calculate. Details of this content will be described later with reference to FIG. 10a.

CPU17 in "Pitching / Rolling Prediction Calculation 1" (32)
Is the suspension pressure correction amount (second correction amount: for each suspension) corresponding to the vertical and lateral accelerations actually applied to the vehicle body, and the first correction amount + second correction amount (for each suspension) is calculated. calculate. The details of this content will be described later with reference to FIG. 10b.

CPU17 in "calculation of the target value" (33), [Suspension initial pressure _{(Pf L0, Pfr 0, Pr} L0, Prr 0) + first correction amount + second correction amount] (calculated intermediate value: for each suspension) To calculate. This content is shown in Figure 10c.

In "warp correction 1" (34), the CPU 17 calculates a turning warp correction value corresponding to the lateral acceleration Rg and the steering speed Ss, and adds this to the calculated intermediate value. The details of this content will be described later with reference to FIG. 10d.

In the "pressure correction" (35), the CPU 17 determines the "calculated intermediate value + warp correction value" corresponding to the line pressure (high pressure) detected by the pressure sensor 13rm and the return pressure (low pressure) detected by the pressure sensor 13rt. to correct. Details of this content will be described later with reference to FIG. 10e.

In the "pressure / current conversion" (36), the CPU 17 sets the above-corrected suspension pressure target value (for each suspension) to
Convert to the current value that should flow through the pressure control valve (80f _L , 80fr, 80r _L , 80rr). The contents will be described later with reference to FIG. 10f.

In the "output" (37), the CPU 17 transfers the current value, which is calculated as described above, to be passed through the pressure control valve to the CPU 18 to each pressure control valve.

When the "output" (37) is completed, the CPU 17 waits for the timer dt to expire (114), restarts the timer dt (19), and reads the state of the sensor and the like and the detected value (20).

If the determined control mode is any of Nos. 5 to 7 shown in Table 2, the CPU 17 causes the "vehicle height deviation calculation 2" in FIG. 9c.
(31V ₁ ), “Pitching / rolling prediction calculation 2” (32
V ₁ ), “calculation of target pressure” (33), “warp correction” (34
V), "Pressure compensation" (35), "Pressure / current conversion" (36)
And "output" (37) are executed in this order.

When the determined control mode is one of No. 3 and 4 shown in Table 2, the CPU 17 causes the "vehicle height deviation calculation 2" (3
1V ₁ ), "Pitching / rolling correction" (32V ₂ ),
The "calculation of target pressure" (33), "pressure correction" (35), "pressure / current conversion" (36) and "output" (37) are executed in this order.

If the determined control mode is either No. 1 or 2 shown in Table 2, the CPU 17 causes the "vehicle height deviation calculation 2" (3
1V ₁ ), "Calculation of target pressure" (33), "Pressure compensation" (3
5), "Pressure / current conversion" (36) and "Output" (37)
Are executed in this order.

Due to the suspension pressure control operation of the CPU 17 described above, the sensor detection value is transferred to the CPU 18 at the dt cycle.
Requested by 17 (subroutine 20), in response to this, CP
The U18 reads the data in the cycle of 3 msec, transfers the read values of the past several times, and transfers the sensor detection value data that has been subjected to the weighted average smoothing to the CPU17. Further, in the CPU 18, the current value data to be passed through the bypass valve 120 in the dt cycle, and the current value data to be passed in the pressure control valve 80fr etc. in the cycle of dt × 3,4,5,6,7 or 8 are further added. But CPU1
7, the current value data is output (latched) to the duty controller 32 each time the CPU 18 receives this transfer. Therefore, the duty controller
32 controls the energization duty so that the current value of the bypass valve 120 (the current value detected by the coil driver 33) becomes the target current value while updating the target current value data at the dt cycle, and dt × While updating the target current value data in the cycle of 3,4,5,6,7 or 8, the energization duty is controlled so that the current value of each pressure control valve becomes the target current value.

The contents of the "vehicle height deviation calculation 1" (31) will be described with reference to Fig. 10a. First, in the overview, the vehicle height sensors 15f _L , 15fr, 15
Vehicle height detection value of r _L , 15 rr Df _L , Dfr, Dr _L , Drr (Register DFL, DF
R, DRL, DRR), heave (height) DHT, pitch (difference between front wheel height and rear wheel height) DPT, roll (right wheel height and left wheel height) DRT and warp (difference between front left wheel vehicle height and front right wheel vehicle height and rear left wheel vehicle height and rear right wheel vehicle height) DWT are calculated. That is, each wheel height (contents of registers DFL, DFR, DRL, DRR)
Attitude parameters for the entire vehicle body (heave DHT, pitch DP
T, roll DRT and warp DWT).

DHT = DFL + DFR + DRL + DRR, DPT =-(DFL + DFR) + (DRL + DRR), DRT = (DFL-DFR) + (DRL-DRR), DWT = (DFL-DFR)-(DRL-DRR). This DPT is calculated in "Pitching error CP calculation" (51), and DRT is calculated in "Rolling error C".
Calculation of R ”(52) and calculation of DWT is“ Warp error ”
Calculation of CW ”(53).

Then, in "calculation of heave error CH" (50), the target heave Ht is derived from the vehicle speed Vs, the heave error amount of the calculated heave DHT with respect to the target heave Ht is calculated, and PID (proportional, integral, derivative) control is performed. In order to perform the PID processing on the calculated heave error amount, the heave correction amount CH corresponding to the heave error
To calculate.

Similarly, in "Calculation of pitching error CP" (51), the target pitch Pt is derived from the vertical acceleration Pg, and the calculated pitch DP
Calculate the pitch error amount of T with respect to the target pitch Pt.
For ID (proportional, integral, derivative) control, the calculated pitch error amount is PID processed to calculate a pitch correction amount CP corresponding to the pitch error.

Similarly, in "Calculation of rolling error CR" (52), the target roll Rt is derived from the lateral acceleration Rg, and the calculated roll DR
Calculate the roll error amount of T with respect to the target roll Rt, and
For ID (proportional, integral, derivative) control, the calculated roll error amount is PID processed to calculate a roll correction amount CR corresponding to the roll error.

Similarly, in “Calculation of Warp Error CW” (53), the target warp Wt is set to zero, and the calculated warp DWT is set to the target warp Wt.
The amount of warp error for PID (proportional, integral,
For differential control, the calculated warp error amount is subjected to PID processing to calculate a warp correction amount CW corresponding to the warp error. When the absolute value of the calculated warp error amount (DWT because the target warp is zero) is less than or equal to a predetermined value (within the allowable range), the warp error amount for PID processing is set to zero, and when it exceeds the predetermined value. Let the amount of warp error for PID processing be −DWT.

Explaining the contents of "calculation of heave error CH" (50) in detail, the CPU 17 reads the target heave Ht corresponding to the vehicle speed Vs from one area (table 2) of the internal ROM and writes it in the heave target value register Ht. (39).

As shown as "Table 2H" in Fig. 10a, the vehicle speed Vs
The target heave Ht associated with the vehicle speed Vs is 80 Km / h
At low speeds below, high value Ht _{1 and} at high speeds above 120Km / h, vehicle speed Vs is low value Ht ₂ , but Vs exceeds 80Km / h and 120Km / h.
In the range of less than / h, the target value changes linearly (may be a curve) with respect to the vehicle speed Vs. In this way, the target value is changed linearly, for example, if 100 Km / h or less, the target value is changed to Ht ₁ , and if 100 Km / h or more, the target value is changed to Ht _2. At around 100 Km / h, the target heave changes in large steps due to a slight change in Vs speed, and the vehicle height frequently goes up and down rapidly at high speeds, resulting in poor vehicle height stability. This is because According to the setting of the above table 2H, the target value changes only slightly when the vehicle speed Vs changes slightly, so the vehicle height target value changes only slightly and the vehicle height stability increases.

The CPU 17 then calculates the aforementioned heave DHT (40). Then, the contents of the register EHT2 in which the previously calculated heave error amount is written are written in the register EHT1 (41), the current heave error amount HT-DHT is calculated, and this is written in the register EHT2 (42). From the above, register EHT1 is set to the previous (ST
The heave error amount before 1) and the current heave error amount are stored in the register EHT2. Next, the CPU 17 writes the content of the register ITH2 in which the error integrated value up to the previous time is written into the register ITH1 (43), and calculates the current PID correction amount ITh by the following formula.

ITh = Kh ₁ · EHT ₂ + Kh ₂ · (EHT ₂ + Kh ₃ · ITH 1) + Kh ₄ · Kh ₅ · (EHT 2 − EHT ₁ ) Kh ₁ · EHT 2 is the P (proportional) term of the PID operation, Kh ₁ is the coefficient of the proportional term, EHT2 is the contents of register EHT2 (the amount of heave error this time).

Kh ₂ · (EHT ₂ + Kh ₃ · ITH 1) is the I (integral) term, Kh
₂ is the coefficient of the integral term, ITH1 is the integral value of the correction amount up to the previous time (the integral value of the correction amount output from the initial pressure setting 16-18), Kh ₃
Is a weighting coefficient between the current error amount EHT2 and the correction amount integrated value ITH1.

Kh ₄ · Kh ₅ · (EHT2-EHT1) is a D (differential) term, and the coefficient of the differential term is Kh ₄ · Kh ₅ , but Kh ₄ uses a value associated with the vehicle speed Vs, For Kh _{5, the} value associated with the steering angular velocity Ss is used. That is, one area of the internal ROM (Table 3
From H), the vehicle speed correction coefficient Kh ₄ associated with the vehicle speed Vs at that time is read, and the steering angular velocity correction coefficient associated with the steering angular velocity Vs at that time is read from one area (table 4H) of the internal ROM. Read Kh ₅ and multiply these by Kh ₄ · Kh ₅
Is the coefficient of the differential term.

As shown as “Table 3H” in FIG. 10a, the vehicle speed correction coefficient Kh ₄ is generally a larger value as the vehicle speed Vs is higher, and the weight of the differential term is increased. This is a correction term in which the differential term tries to quickly accommodate the change in the heave to the target value, and the higher the vehicle speed, the more the brake pedal is depressed / released.
This is because the speed of the vehicle height change due to acceleration / deceleration by the accelerator pedal, turning / turning back by turning the steering wheel, etc. is fast, so that the target vehicle height can be quickly stabilized in response to this fast speed. On the other hand, if the vehicle speed Vs is above a certain level (table
At 3H, 40km / h or more), when the brake pedal is depressed / released, the accelerator pedal accelerates / decelerates, the steering wheel turns / turns back, etc., the body posture changes rapidly and becomes extremely large. However, an excessive differential term that quickly compensates for such a sudden change in posture deteriorates the vehicle height control stability. Therefore table 3h
More precisely, the vehicle speed correction coefficient Kh ₄ changes greatly with respect to changes in the vehicle speed Vs when the vehicle speed Vs is low, and decreases with increasing vehicle speed Vs. That is, when the vehicle speed Vs is low, the weight of the differential term changes greatly with respect to the vehicle speed fluctuation, but when the vehicle speed Vs is high, the weight change of the differential term with respect to the vehicle speed fluctuation is small.

As shown as “Table 4H” in FIG. 10a, the steering angular velocity correction coefficient Kh ₅ is generally a larger value as the steering angular velocity Ss is higher, and the weight of the differential term is increased. This is a correction term in which the differential term tries to quickly accommodate the change in heave to the target value, and the higher the steering angular velocity Ss, the faster the change in the traveling direction and the greater the changes in vertical acceleration and lateral acceleration. This is because the target vehicle height is quickly stabilized in response to the rapid changes in vertical and lateral accelerations. On the other hand, when the steering angular velocity Ss is below a certain level (50 ° / msec or less in Table 4H), the change in the traveling direction is extremely gentle and the weighting of the differential term is small, and when it exceeds 50 ° / msec and 400 ° / msec, the steering angular velocity is The vehicle height changes at a speed substantially proportional to Ss. At steering angular velocities of 400 ° / msec or more, the change in the vehicle body posture becomes abrupt and extremely large, and an excessive differential term that quickly compensates for such a sudden posture change impairs vehicle height control stability. Therefore, the coefficient Kh of the differential term corresponding to the steering angular velocity Ss
₅ is a constant value when Ss is 50 ° / msec or less, a high value that is substantially proportional to Ss when it exceeds 50 ° / msec and 400 ° / msec or less, and is 400 ° / msec when it exceeds 400 ° / msec. Is a constant value.

With the introduction of the differential term Kh ₄ · Kh ₅ · (EHT2-EHT1) explained above, the coefficient Kh ₄ is increased corresponding to the vehicle speed Vs, and the coefficient Kh ₅ is increased corresponding to the steering angular speed Ss. By doing so, weighted differential control corresponding to the vehicle speed Vs and the steering angular speed Ss is realized, and highly stable vehicle height control is realized with respect to variations in the vehicle speed Vs and the steering angular speed Vs.

As described above, PID calculation of heave error correction amount ITh (44)
When calculated with, the CPU 17 determines that the calculated heave error correction amount I
Write Th to the register ITH2 (45) and multiply it by the heave error correction amount weighting coefficient Kh ₆ (weighting for pitch error correction amount, roll error correction amount, and warp error correction amount, which will be described later: contribution ratio in the total correction amount). Write to the heave error register CH.

When the heave error CH calculation (50) is executed as described above, the CPU 17 executes the "pitching error CP calculation" (51) to calculate the pitch error correction amount CP in the same manner as the heave error CH and calculate the pitch error. Write to register CP. In this case, the pitch target value PT corresponding to the heave target value HT is the data Pt (vertical acceleration) corresponding to the vertical acceleration Pg at that time from one area of the internal ROM of the CPU 17 (table 2P).
The reverse pitch that cancels the pitch due to Pg) is read and obtained.

Fig. 11a shows the contents of table 2P. The pitch target value Pt corresponding to the vertical acceleration Pg is in a direction (decrease) that cancels the pitch appearing by the vertical acceleration Pg. The region a is intended to save energy by increasing the target pitch as the vertical acceleration Pg increases (decreases). The region b is considered to be an abnormal sensor due to abnormal Pg, so the pitch target value should be made smaller. Actually, it is to prevent giving a target value even if Pg does not occur. For other calculation processing operations, refer to "Calculation of heave error CH" described above.
Same as the content of (50), P and HT and Ht of step 39
Replace with T, Pt, replace the DHT calculation formula in step 40 with the above DPT calculation formula, replace EHT1, EHT2 in step 41 with EPT1, EPT2, EHT2, HT, DHT in step 42 with EPT2, PT, Replace with DPT,
The ITH1 and ITH2 in step 43 are replaced with ITP1 and ITP2, the ITh calculation formula of the subroutine 44 is replaced with a pitch error correction amount ITp calculation formula which has a completely corresponding relationship with it, and the table 3H is used for pitch correction amount ITP calculation. Replace with the coefficient table (3P),
Table 4H is also a coefficient table (4
P), replace ITH2, ITh in step 45 with ITP2, ITp, and replace CH, Kh ₆ , ITh with CP, Kp ₆ , ITp in step 46 to calculate the pitch error CP. A flow chart showing the contents of (51) appears. The CPU 17 executes the processing represented by this flowchart.

Next, the CPU 17 executes "rolling error CR calculation" (52), calculates the roll error correction amount CR in the same manner as the heave error CH, and writes it in the roll error register CR. In this case, the roll target value RT corresponding to the heave target value HT is the data Rt (lateral acceleration) corresponding to the lateral acceleration Rg at that time from one area of the internal ROM of the CPU 17 (table 2R).
Roll target value corresponding to Rg) is read and obtained.

Figure 11b shows the contents of Table 2R. The roll target value Rt corresponding to the lateral acceleration Rg is in a direction (decreasing) for canceling the roll that appears due to the lateral acceleration Rg. The region a is intended to save energy by increasing the target roll as the lateral acceleration Rg increases (decreases). The region b is considered to be an abnormal sensor due to an abnormal Rg. This is to prevent the roll target value from being given even if Rg has not actually occurred. For other calculation processing operations, refer to "Calculation of heave error CH" (5
0) is the same as that in step 39, and HT, Ht in step 39 is changed to RT, R
Replace with t, replace the DHT formula in step 40 with the above DRT formula, replace EHT1, EHT2 in step 41 with ERT1, ERT2, replace EHT2, HT, DHT in step 42 with ERT2, RT, DPT. Replace,
ITH1 and ITH2 in step 43 are replaced with ITR1 and ITR2, the ITh calculation formula of the subroutine 44 is replaced with a roll error correction amount ITr calculation formula that has a completely corresponding relationship with it, and the table 3H is used for calculating the roll correction amount ITr. Replace with the coefficient table (3R),
Table 4H is also a coefficient table (4
Substituted with R), the ITH2, ITh in step 45 is replaced with ITR2, ITr, and CH of the step 46, by replacing the Kh _6, ITh CR, and Kr _6, ITr, "calculation of roll error CR" A flow chart showing the contents of (51) appears. The CPU 17 executes the processing represented by this flowchart.

Next, the CPU 17 executes "calculation of warp error CW" (53), calculates the warp error correction amount CW in the same manner as the heave error CH, and writes it in the warp error register CW. In addition, in this, the warp target value PW corresponding to the heave target value HT
Is set to zero. The other operation processing operations are the same as the content of the above-mentioned "operation of heave error CH" (50),
Replace HT, Ht in step 39 with WT, 0, and replace D in step 40 with
Replace the HT formula with the above DWT formula and
Replace 1, EHT2 with EWT1, EWT2 and replace the contents of step 42 with DWT
When the absolute value of is less than the predetermined value Wm (within the allowable range)
WT is set to 0, and when Wm is exceeded, WT is set to −DWT, and WT is changed to the contents written in register EWT2.
Replace ITH2 with ITW1 and ITW2, and use the ITh calculation formula of subroutine 44 to calculate the warp error correction amount IT
w Replace with the calculation formula, replace Table 3H with the coefficient table (3W) for calculating the warp correction amount ITr, and replace Table 4H with the coefficient table (4W) for calculating the warp correction amount ITw. , ITh with ITW2, ITw, and step 46
Replacing CH, Kh ₆ ,, ITh with CW, Kw ₆ , ITw, a flowchart showing the contents of "Operation of warp error CW" (53) appears. The CPU 17 executes the processing represented by this flowchart.

As described above, when the heave error correction amount CH, the pitch error correction amount CP, the roll error correction amount CR, and the warp error correction amount WP are calculated, the CPU 17 calculates these correction amounts as the suspension pressure correction amount EHf _{L of} each wheel portion. (suspension
100f _L ), EHfr (100fr), EHr _L (100r _L ), EH
Convert back to rr (addressed to 100rr). That is, as follows,
Calculate the suspension pressure correction amount.

EHf _L = Kf _L · Kh ₇ · (1/4) · (CH-CP + CR + CW), EHfr = Kfr · Kh ₇ · (1/4) · (CH-CP – CR-CW), EHr _L = Kr _L · Kh ₇ · (1/4) · (CH + CP + CR-CW), EHrr = Krr · Kh ₇ · (1/4) · (CH + CP-CR + CW) Coefficients Kf _L , Kfr, Kr _L , Krr are line pressure reference point 13rm And return pressure reference point 13rt, suspension 100f _L , 10
This is a correction coefficient for compensating the suspension supply pressure deviation due to the difference in pipe length of 0fr, 100r _L , 100rr. Kh ₇
Is a coefficient for increasing / decreasing the vehicle height deviation correction amount corresponding to the steering angular velocity Ss, and is read from one area (table 5) of the internal ROM of the CPU 17 corresponding to the steering angular velocity Ss. When the steering angular velocity Ss is large, a large attitude change is expected and the attitude error amount is expected to increase. Therefore, the coefficient Kh ₇
Is roughly set to be large in proportion to the steering angular velocity Ss. However, when the steering angular velocity Ss is lower than a certain level (50 ° / msec or less in Table 5), the change in the traveling direction is extremely gentle and the posture change is small, and it is more than 50 ° / msec.
At ° / msec or less, the posture change appears at a speed substantially proportional to the steering angular speed Ss. At steering angular velocities exceeding 400 ° / msec, the change in the vehicle body attitude becomes abrupt and extremely large, and the vehicle height control stability is impaired by an excessive amount of correction that quickly compensates for such a sudden attitude change. Therefore, the correction coefficient Kh ₇ corresponding to the steering angular velocity Ss is Ss of 50 ° / ms.
It is a constant value below ec, a high value that is substantially proportional to Ss above 50 ° / msec and 400 ° / msec, and a constant value at 400 ° / msec above 400 ° / msec.

Next, the content of the "pitching / rolling prediction calculation" (32) will be described with reference to FIG. 10b. The above-mentioned "vehicle height deviation calculation" (31) roughly determines the current vehicle body attitude from the current vehicle height, vertical acceleration, and lateral acceleration so as to maintain the vehicle body attitude at a predetermined appropriate value (feedback). do it),
While the suspension pressure is adjusted (feedback control) so that the current vehicle body attitude becomes the predetermined appropriate one, the "pitching / rolling prediction calculation" (32) is roughly It is intended to control longitudinal and lateral acceleration. That is, it is intended to suppress changes in the vertical acceleration Pg and the lateral acceleration Rg of the vehicle body.

The CPU 17 first calculates a correction amount CGT for suppressing a change in pitch due to a change in vertical acceleration Pg (55 to 58). In this case, write the contents of the register GPT2 that previously wrote the correction amount corresponding to Pg to the register GPT1 (55), and set the internal RO
The correction amount Gpt corresponding to Vs and Pg is read from one area of M (table 6) and is written in the register GPT2 (5
7). The data Gpt in Table 6 is grouped with Vs as an index, and the CPU 17 specifies the group with Vs,
Read the Pg-compatible data Gpt in the specified group. In each group, the smaller the Vs is assigned, the dead zone a width (Gpt = in Table 6 shown in FIG. 10b).
The width of 0) is set to a large value. b is a region where the gain is increased and the control performance is improved as the vertical acceleration Pg is increased, and c is a region where the control performance is reduced because more than the sensor is considered.

Next, the CPU 17 calculates the correction amount CGP for suppressing the change in the vertical acceleration Pg by the following equation and writes it in the register CGP (58).

CGP = Kgp ₃ · _{[Kgp 1 · GPT2 + Kgp 2 ·} (GPT2-GPT1) ] GPT2 represents the content of register GPT2, this is a correction amount Gpt read from the table 6. GPT1 is the content of the register GPT1, and is the correction amount read from the table 6 last time. Kgp ₁ of P (proportional) term Kgp ₁ · GPT2 is the coefficient of the proportional term.

D (differential) term Kgp Kgp ₂ of ₂ · (GPT2-GPT1) is a coefficient of differential term, this factor Kgp _2, the internal in response to the vehicle speed Vs ROM
It is read from one area (table 7). First
As shown as “Table 7” in FIG. 10b, the coefficient Kgp ₂
Is a larger value as the vehicle speed Vs is higher, and the weight of the differential term is increased. This is a correction term in which the differential term tries to suppress the change in the vertical acceleration Pg faster, and the higher the vehicle speed, the stepping / release of the brake, acceleration / deceleration by the accelerator pedal, turning / turning back by turning the steering wheel, etc. This is because the change in the vertical acceleration Pg due to is fast, so that it is attempted to suppress this quickly in response to this fast change. On the other hand, when the vehicle speed Vs exceeds a certain level, when the brake pedal is depressed / released, the accelerator pedal accelerates / decelerates, or the steering wheel turns / turns back, the longitudinal acceleration Pg changes rapidly and is extremely large. Therefore, an excessive differential term that suppresses such a rapid change quickly impairs the stability of suppressing the vertical acceleration. Therefore, more precisely, the coefficient Kgp _{2 of the} table 7 changes greatly with respect to the change of the vehicle speed Vs when the vehicle speed Vs is low, and is constant when the vehicle speed Vs is a predetermined value or more. That is, when the vehicle speed Vs is low, the weight of the differential term largely changes with respect to the vehicle speed variation, but when the vehicle speed Vs is high, the differential term weight does not change with respect to the vehicle speed variation.

The calculated correction amount CGP for suppressing the change in the vertical acceleration Pg is a pitch correction amount for the suspension, and Kgp ₃ is a weighting coefficient for the roll correction amounts CGR and GES described later.

Next, the CPU 17 calculates a correction amount CGR for suppressing the roll change due to the change of the lateral acceleration Pg (that is, suppressing the change of the lateral acceleration Pg) (59 to 62). In this, the previous R
The contents of the register GRT2 in which the correction amount corresponding to g is written are written in the register GRT1 (59), the correction amount Grt corresponding to Vs and Rg is read from one area (table 8) of the internal ROM, and this is stored in the register GRT2. Write (61). The data Grt in Table 8 is grouped using Vs as an index.
Specifies the group with Vs, and within the specified group,
Read the data Grt corresponding to Rg. Each group has a small V
The width of the dead zone a (the horizontal width of Grt = 0 in the table 8 shown in FIG. 10b) is set to be larger as it is assigned to s. b is a region where the gain is increased and the control performance is improved as the lateral acceleration Rg is increased, and c is a region where the control performance is degraded because a sensor abnormality is considered.

Next, the CPU 17 calculates the correction amount CGR for suppressing the change in the lateral acceleration Rg by the following equation and writes it in the register CGR (62).

CGR = Kgr ₃ · _{[Kgr 1 · GRT2 + Kgr 2 ·} (GRT2-GRT1) ] GRT2 represents the content of register GRT2, a correction amount Grt read from this table 8. GRT1 is the content of the register GRT1 and is the correction amount read from the table 8 last time. P (proportional) term Kgr ₁ · Kgr ₁ of GRT ₂ is a coefficient of the proportional term.

D (differential) term Kgr Kgr ₂ of ₂ · (GRT2-GRT1) is a coefficient of differential term, this factor Kgr _2, the internal in response to the vehicle speed Vs ROM
It is read from one area (table 9). First
As shown as “Table 9” in FIG. 10b, the coefficient Kgr ₂
Is a larger value as the vehicle speed Vs is higher, and the weight of the differential term is increased. This is a correction term in which the differential term tries to suppress the change in lateral acceleration Rg faster, and the higher the vehicle speed, the faster the change in lateral acceleration Rg due to turning / turning back due to rotation of the steering wheel. This is because it is intended to quickly suppress this by correspondingly. On the other hand, when the vehicle speed Vs exceeds a certain level, when the turning / turning back by the rotation of the steering is suddenly performed, the change of the lateral acceleration Rg becomes rapid and extremely large. An excessive differential term impairs the stability of lateral acceleration suppression. Therefore, the coefficient Kgr _{2 in} Table 9
In more detail, with respect to the change in the vehicle speed Vs, the change is large when the vehicle speed Vs is low, and is constant when the vehicle speed Vs is equal to or higher than a predetermined value. That is, when the vehicle speed Vs is low, the weight of the differential term largely changes with respect to the vehicle speed variation, but when the vehicle speed Vs is high, the differential term weight does not change with respect to the vehicle speed variation.

The calculated CGR is a roll correction amount for the suspension, and Kgr ₃ is a weighting coefficient for the above-described pitch correction amount CGP and a roll correction amount GES described later, but when the vehicle speed Vs is low, the lateral acceleration Rg Since the rate of change is low,
In the low speed range, the contribution ratio of this roll correction amount CGR is lowered, and in the high speed range, it becomes a constant value, so that it is a region of the internal ROM (Table 1
The coefficient data Kgr ₃ corresponding to the velocity Vs is stored in (0). C
The PU 17 reads the coefficient Kgr ₃ corresponding to the speed Vs and uses it for the above-described calculation of CGR.

Changes in steering position (rotational position) (steering angular velocity
Ss) changes the lateral acceleration Rg, and the rate of change also depends on the vehicle speed Vs. That is, the change in the lateral acceleration Rg is the steering angular velocity Ss.
And Vs, the roll correction amount Ges required to suppress this change is written in one area (table 11) of the internal ROM of the CPU 17. The CPU 17 checks whether the steering angular acceleration Sa is substantially zero (64), and if it is not substantially zero, reads the roll correction amount Ges corresponding to the combination of Vs and Ss from the table 11 and registers it. Write to GES (6
Five). When it is substantially zero (the previous steering angular velocity and the current steering angular velocity are equal: the roll correction amount Ges read out last time can be directly used as the current roll correction amount), and the register GES
The update write to (65) is not executed.

The CPU 17 then calculates the calculated pitch correction amount CGP and roll correction amount C.
The GR and roll correction amount DES are converted to the pressure correction amount for each suspension, and this pressure correction amount is the value EHf _L , EHfr, EHr _L , EHrr calculated in "Vehicle height deviation calculation" (31) previously.
Add to (registers EHf _L , EHfr, EHr _L , EHrr contents),
The obtained sum Ehf _L , Ehfr, Ehr _L , Ehrr is set to the register EHf _L , EHfr, EHr _L ,
Update and write to EHrr (66).

Ehf _L = EHf _L + Kgf _L · (1/4) · (-CGP + Kcgrf · CGR + Kg
ef _L・ GES) Ehfr ＝ EHfr ＋ Kgfr ・ (1/4) ・ (-CGP-Kcgrf ・ CGR ＋ Kg
efr ・ GES) Ehr _L ＝ EHr _L ＋ Kgr _L・ (1/4) ・ (CGP ＋ Kcgrr ・ CGR ＋ Kger
_L・ GES) Ehrr = EHrr ＋ Kgrr ・ (1/4) ・ (CGP ＋ Kcgrr ・ CGR ＋ Kger
r · GES) The first term on the right-hand side of the above equation is the value that was previously calculated in “Vehicle height deviation calculation” (31) and was written in the registers EHf _L , EHfr, EHr _L , EHrr. Yes, the second term on the right side is the pitch correction amount CGP, the roll correction amount CGR, and the roll correction amount GES,
It is a value converted into a pressure correction value for each suspension. Note that the coefficients of the second term on the right side Kgf _L , Kgfr, Kgr _L and Kgrr
Is Kgf _L ＝ Kf _L・ Kgs, Kgfr ＝ Kfr ・ Kgs, Kgr _L ＝ Kr _L・ Kgs, Kgrr ＝ Krr ・ Kgs, and Kf _L , Kfr, Kr _L , Krr are of each suspension with respect to the pressure reference point. A coefficient for correcting a pressure error due to a variation in the pipe length (a pipe length correction coefficient), and Kgs is a coefficient that is predetermined in association with the steering angular velocity Ss, as shown in Table 12. "Vehicle height deviation calculation" (31)
The pressure correction value calculated in “Pitching / rolling prediction calculation” (32) for the pressure correction value calculated in Step 3 to suppress acceleration change (the second term on the right side of the above equation: (1/4)
(-CGP + Kcgrf / CGR + Kgef _L / GES) etc.) is specified. If the steering angular velocity Ss is large, a rapid acceleration change is expected, and it is preferable to increase the weighting of the pressure correction value for suppressing the acceleration change. Therefore, the coefficient Kgs is generally set to be large in proportion to the steering angular velocity Ss. However, the rudder angular velocity Ss decreased to some extent (50 ° / m in Table 12).
sec), the change in acceleration is extremely small, 50 ° / msec
Above 400 ° / msec or less, the acceleration changes at a speed substantially proportional to the steering angular speed Ss. At a steering angular velocity of 400 ° / msec or more, the turning radius changes rapidly and becomes extremely large, resulting in extremely large acceleration changes (especially lateral acceleration). An excessive amount of correction that quickly compensates for such rapid acceleration changes. , The stability of acceleration control deteriorates. Therefore, the weighting factor Kgs corresponding to the steering angular velocity Ss is Ss of 50 ° / ms.
It is a constant value below ec, a high value that is substantially proportional to Ss above 50 ° / msec and 400 ° / msec, and a constant value at 400 ° / msec above 400 ° / msec.

Next, the CPU 17 executes the “calculation of target pressure” (33) shown in FIG. 10c, and the initial pressure data written in the initial pressure registers PFL ₀ , PFR ₀ , PRL ₀ , PRR ₀ (step 16- (Set in 18) is calculated by subroutine 66 and is the sum of the correction pressure for vehicle height deviation adjustment and the correction pressure for acceleration suppression control (registers EHf _L , E
Hfr, EHr _L , EHrr contents) to calculate the pressure to be set for each suspension, and register EHf _L , EHfr, EH
Update and write to r _L and E Hrr (67).

The content of the "warp correction 1" (34) will be described with reference to FIG. 10d. This warp correction 1 (34) calculates an appropriate target warp DWT from the lateral acceleration Rg and the rotational speed Ss of the steering shaft (73), and the above-mentioned registers EHf _L and EHf
The warp that appears when the contents of r, EHr _L , and EHrr are output is calculated, and the error warp amount for this target warp DWT is calculated (74 to 76), which is required to set this error warp amount to zero. Calculate the pressure correction values dHf _L , dHfr, dHr _L , dHrr (77) and store these pressure correction values in the registers EHf _L , EHfr, EH.
It is added to the contents of r _L and EHrr, and the sum is updated and written in these registers (78).

In one area (table 14) of internal ROM of CPU17, lateral acceleration
The warp target value Edr corresponding to Rg is written, and the table 15 shows the warp target value Eds corresponding to the steering speed Ss.
Is written in the table 16, and the warp correction amount corresponding to the vehicle body longitudinal inclination and lateral acceleration Rg (lateral inclination) specified by the values of the registers EHf _L , EHfr, EHr _L , and EHrr to be output from now on. Idrs are written. Incidentally, the longitudinal _{inclination, K = | (EHf L +} EHfr) / (EHr L + EHrr) | expressed in has been written data group of K correspondence written in the table 16, the data in each data group, horizontal It is associated with the acceleration Rg.

The CPU 17 reads out the warp target value Edr corresponding to the lateral acceleration Rg from the table 14, the warp target value Eds corresponding to the steering speed Ss, and registers EHf _L , EH
The warp correction amount Edrs corresponding to the vehicle longitudinal inclination and lateral acceleration Rg (lateral inclination) defined by the values of fr, EHr _L , and EHrr is read from the table 16, and the warp target value DWT is calculated by the following equation ( 73).

DWT = Kdw ₁ · Edr + Kdw ₂ · Eds + Kdw ₃ · EDrs The CPU17 then writes the contents of the registers EHf _L , EHfr, EHr _L , EHrr
Calculate the warp (EHf _L −EHfr) − (EHr _L −EHrr) defined by f _L , EHfr, EHr _L , EHrr, and check whether it is within the allowable range (dead zone) ( 74), if it is out of the allowable range, calculated from target warp DWT Warp (EHf _L −EHfr) − (EHr _L −EHr
The value obtained by subtracting r) is written to the warp error correction amount register DWT (75), and when it is within the allowable range, the content (DWT) of the register DWT is not changed. Then, the warp error correction amount D
WT (contents of the register DWT) is multiplied by the weighting coefficient Kdw ₄ and the product is updated and written in the register DWT (76), and this warp-awa correction amount DWT is converted into each suspension pressure correction amount (77), The corresponding corrections are made in the registers EHf _L , EHfr, EHr _L
And added to the contents of EHrr (78).

Explaining the contents of the “pressure correction” (35) with reference to FIG. 10e, the CPU 17 determines that the detected pressure Dph of the pressure sensor 13rm (register
The correction value PH for compensating the fluctuation of the output pressure of the pressure control valve due to the fluctuation of the line pressure corresponding to the contents of DPH) is read from one area (table 13H) of the internal ROM, and the pressure sensor 13r
Compensation values PLf (front wheel side correction value) and PLr (rear wheel side correction value) that correspond to the detected pressure Dp _L (contents of register DPL) of t and compensate for the fluctuation of the output pressure of the pressure control valve due to the fluctuation of the return pressure.
Is read from one area of the internal ROM (table 13L), and the pressure correction value PDf = P that compensates for fluctuations in the pressure control valve output pressure due to fluctuations in the line pressure and return pressure applied to the pressure control valve.
Calculate H-PLf and PDr = PH-PLr (68,69). The correction value corresponding to the return pressure is divided into the front wheel side and the rear wheel side because the front wheel side is close to the reservoir, the rear wheel side is far from the reservoir, and the pressure sensor 13rt for low pressure detection is the rear wheel side return. Since the pressure is detected, the return pressure difference between the rear wheel side and the front wheel side is relatively large, and this is to reduce the error due to this. Table 13L stores two groups, a correction value data group assigned to the rear wheel side and a correction value data group assigned to the front wheel side, the latter data for the front wheel suspension and the former data for the rear wheel suspension. A correction value corresponding to the pressure detected by the pressure sensor 13rt at that time is read from the group.

After calculating the correction values PDf and PDr, the CPU 17 adds these correction values to the contents of the registers EHf _L , EHfr, EHr _L , and EHrr, and also performs the “pressure / current conversion” by referring to the register EHf _L FIG. 10f. Explaining the contents of (36), the CPU 17 controls the pressure control valves 80f _L , 80fr, for generating the pressure indicated by the data EHf _L , EHfr, EHr _L and EHrr of the registers EHf _L , EHfr, EHr _L and EHrr. 80r _L and 80rr
Current values Ihf _L , Ihfr, Ihr _L and Ihrr to be applied to
It is read from the current conversion table 1 and written in the current output registers IHf _L , IHfr, IHr _L and IHrr (72).

The data of these current output registers IHf _L , IHfr, IHr _L and IHrr are transferred to the CPU 18 to the pressure control valves 80f _L , 80fr, 80r _L and 80rr by the subroutine of “output” (37), and the CPU 18 It is given to the duty controller 32.

"Vehicle height deviation calculation 2" (31v ₁ , 31V ₂ , 31V ₃ ) is the steering angular velocity SS
Is substantially zero (no steering), the calculation relating to the steering angular velocity SS and the derivative control term are omitted from the "vehicle height deviation calculation 1" (31). ing. That is, the PID calculation of the subroutine 44 of "calculation of heave error" (50) of "vehicle height deviation calculation 1" (31),
With the differential (D) term (EHT2-EHT1) omitted, and with all the coefficients Kh _{1 to} Kh ₆ fixed, "Pitching error calculation" (51), Rolling error calculation (5)
2) and “Calculation of warp error” (53) are also said to be omitted and fixed in the same way.

Since "pitching / rolling prediction calculation 2" (32v ₁ ) is also executed when the steering angular velocity SS is substantially 0 (no steering), the above-mentioned "pitching / rolling prediction calculation 1" (32 ), The calculation related to the steering angular velocity SS is omitted. That is, subroutines 58 and 62
The differential terms (GPT2-GPT1, GRT2-GRT1) of are omitted and the coefficients Ges and Kgs are fixed values.

Also in "warp correction 2" (34V), the steering angular velocity SS is practically 0
Since it is executed when (no steering), the second term "Kdw2Eds" on the right side is omitted from the arithmetic expression of the subroutine 73 of "warp correction 1" (34) described above. .

The "pitching / rolling correction" (32V ₂ ) is the same as the above-mentioned "pitching / rolling prediction calculation 1" (32), but omits the calculation related to the steering angular velocity SS. That is, the derivative terms of subroutines 58 and 62 (GPT2-GPT1, GR
T2-GRT1) is omitted, and the coefficients Ges and Kgs are set to fixed values. Further, as in steps 101 and 102 in FIG.
And Rg are substantially zero, and when Pg is substantially zero, set CGP to 0 and perform steps 55 to 58.
(FIG. 10b) is skipped and only steps 59 and below are executed. When Rg is substantially zero, CGR is set to 0, steps 59 to 62 are skipped, and steps 55 to 58 and
It is supposed to perform 63-66.

〔The invention's effect〕

As described above, according to the present invention, the state of the sensor or the like and the detected value are read by the mode detecting means (17) at the dt cycle, and the mode is determined. Then, in the warp fluctuation traveling mode (No. 8 to 5 in Table 2) in which the posture change is predicted to be rapid such that the determined mode causes a warp change in the vehicle body, the first cycle of dt or more and less than the first cycle is performed. In the stable driving mode (No. 1 or 2 in Table 2) where the posture change is predicted to be gentle in 3 cycles (dt × 3, 4 or 5), the first value larger than dt
In the cycle (dt × 8 or 7), the calculation means (17) calculates pressure correction information for compensating (suppressing) the posture change, and the electric biasing means (32, 33) indicate this pressure correction information. Pressure control means (80fr) to add pressure compensation to the suspension
Energize.

Therefore, in the warp fluctuation traveling mode, the suspension pressure correction is executed in the short third cycle, and in the stable traveling mode, the suspension pressure correction is executed in the long first cycle to correspond to the predicted change speed of the vehicle height posture. The suspension pressure correction operation is performed at the speed.

Even when the suspension pressure correction operation in the stable running mode is being performed (until the update calculation timing of the stable running mode is reached), the mode detection means (17) has a dt shorter than the third cycle and shorter than the first cycle. The mode, etc. is read by reading the state of the sensor etc., the detected value, etc. at the cycle, and when the mode is switched, the calculation means (17) calculates the pressure correction value corresponding to the new mode and Biasing means (32,3
3) electrically activates the pressure control means (80fr) so as to apply the pressure correction indicated by the pressure correction information to the suspension, so that the switching delay of the control mode is within dt,
The conventional mode switching delay is greatly reduced. That is,
The delay of the suspension pressure correction operation at the time of changing from the state where the vehicle body posture is highly stable to the state where the vehicle body posture changes abruptly is reduced.

[Brief description of drawings]

FIG. 1 is a block diagram showing a suspension pressure supply system according to an embodiment of the present invention. FIG. 2 is an enlarged vertical sectional view of the suspension 100f _L shown in FIG. FIG. 3 is an enlarged vertical sectional view of the pressure control valve 80f _L shown in FIG. FIG. 4 is an enlarged vertical sectional view of the cut valve 70f _L shown in FIG. FIG. 5 is an enlarged vertical sectional view of the relief valve 60f _L shown in FIG. FIG. 6 is an enlarged vertical sectional view of the main check valve 50 shown in FIG. FIG. 7 is an enlarged vertical sectional view of the bypass valve 120 shown in FIG. FIG. 8 is a block diagram showing the configuration of an electric control system that controls the suspension pressure in accordance with the detected values of the vehicle height sensor, the pressure sensor, etc. of the suspension pressure supply system shown in FIG. 9a, 9b and 9c are flowcharts showing the control operation of the microprocessor 17 shown in FIG. 10a, 10b, 10c, 10d, 10e and 10f are flowcharts showing the contents of the subroutine shown in FIG. 9c. 11a and 11b are graphs showing the contents of data written in the internal ROM of the CPU 17. 1: Pump, 2: Reservoir, 3: High pressure port 4: Accumulator, 6: Front high pressure supply pipe, 7: Accumulator 8: High pressure supply pipe, 9: Rear high pressure supply pipe, 10: Accumulator 11: Reservoir return pipe, 12 : Drain return pipe 13f _L , 13fr, 13r _L , 13rr, 13rm, 13rt: Pressure sensor 14f _L , 14fr, 14r _L , 14rr: Drain 15f _L , 15fr, 15r _L , 15rr: Vehicle height sensor 16p: Vertical Accelerometer, 16r: Lateral accelerometer 17: Microprocessor, 18: Microprocessor 19: Battery, 20: Ignition switch 21: Constant voltage power circuit, 22: Relay, 23: Backup power circuit 24: Brake lamp, 25: Vehicle speed synchronization Pulse generator 26: Rotary encoder 27: Absolute encoder 28: Liquid level detection switch, 29 _{1 to} 29 ₃ : A / D converter 30 ₁ to 30 ₃ : Signal processing circuit, 31: Low pass filter 32: Duty controller, 33: Coil driver 34: Input / output circuit, 50: Main check Kubarubu 51: valve body, 52: input port 53: Output port 54: valve seat, 55: through flow opening 56: compression coil spring, 57: ball valve _{60fr, 60f L, 60rr, 60r} L: relief valve, 61: Valve base 62: Input port, 63: Low pressure port, 64: First guide 65: Filter, 66: Valve body, 67: Second guide 68: Valve body, 69: Compression coil spring 60m: Main relief valve 70fr, 70f _L , 70rr, 70r _L : Cut valve 71: Valve base, 72: Line pressure port, 73: Pressure adjusting input port 74: Oil discharge port, 75: Output port, 76: 1st guide 77: Guide, 78: Spool 79: Compression coil spring 80fr, 80f _L , 80rr, 80r _L : Pressure control valve 81: Sleeve, 82: Line pressure port, 83: Groove 84: Output port, 85: Low pressure port, 86: Groove 87: High pressure port, 88: Target Pressure space, 88f: Orifice 89: Low pressure port, 90: Spool, 91: Groove 92: Compression coil spring, 93: Valve body 94: Flow path, 95: Needle valve, 96: Fixed valve 97: Plunger, 98a: York, 98b: end plate 98c: low pressure port, 99: electric coils _{100fr, 100f L, 100rr, 100r} L: suspension _{101fr, 101f L, 101rr, 101r} L: shock absorber 102fr, 102f _L, 102rr , 102r _L : Piston rod 103: Piston, 104: Inner cylinder, 105: Upper chamber, 106: Lower chamber, 107: Side port, 108: Vertical through port 109: Valve attenuation device, 110: Lower space, 111: Piston 112 : Lower chamber, 113: Upper chamber, 114: Outer cylinder 120: Bypass valve, 121: Input port 122: Low pressure port, 122a: Low pressure port, 122b: Flow path 123: First guide, 124a: Valve body 124b: Compression coil Spring, 125: Needle valve 129: Electric coil

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshio Yutani, 1 Toyota Town, Toyota City, Aichi Prefecture, Toyota Motor Corporation (72) Inventor, Toshio Onuma 1, Toyota Town, Aichi Prefecture Toyota Motor Corporation ( 72) Inventor Takashi Yonekawa 1 Toyota-cho, Toyota-shi, Aichi Toyota Motor Co., Ltd. Examiner Shogo Oshima (56) References JP 63-46910 (JP, A) Special table Sho 60-500662 (JP, A) )

Claims (1)

[Claims] 1. A pressure source for supplying a pressure fluid to a suspension which expands and contracts according to the supplied pressure; a pressure control means between the pressure source and the suspension, which sets a suspension pressure to a target pressure; Height detecting means for detecting the height of the supported vehicle body; speed detecting means for detecting vehicle traveling speed; acceleration detecting means for detecting longitudinal acceleration and lateral acceleration applied to the vehicle body; steering detecting means for detecting steering of a steering shaft A warp fluctuation running mode and a pitching / rolling change that cause a warp change, which is a twist change of the vehicle body about the longitudinal axis of the vehicle body, at a predetermined cycle dt based on the detection information of the speed detection means, the acceleration detection means, and the steering detection means. Pitching / rolling variable driving mode and stable driving mode When the mode detecting means detects the stable running mode; detect mode detecting means
Pitching / rolling change traveling mode is derived by deriving first pressure correction information for compensating for a deviation of the height detected by the height detecting means with respect to a reference height indicated by the height instruction information in a first cycle larger than dt. Dt or more when detecting
In a second cycle equal to or shorter than the cycle, in addition to deriving the first pressure correction information, deriving pressure correction information for compensating for pitching / rolling and deriving the second pressure correction information by adding it to the first pressure correction information. However, when the warp fluctuation traveling mode is detected, in addition to deriving the second pressure correction information, the pressure correction information for compensating for the warp is derived in the third cycle of dt or more and less than the first cycle. 2 Third added to pressure correction information
A suspension unit comprising: a calculation unit that derives pressure correction information; and an electric biasing unit that electrically biases the pressure control unit so that the pressure correction indicated by the pressure correction information derived by the calculation unit is applied to the suspension pressure. Pressure control device.