JP2959331B2 - Vehicle with steering assist device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle having a power steering mechanism with a variable assist amount, and more particularly, to a driver's attention by adjusting the assist state of the power steering mechanism when the driver's arousal level is reduced. A vehicle with a steering assist device.

[0002]

2. Description of the Related Art In recent years, power steering devices have become widespread for assisting a force for operating a steering wheel (hereinafter referred to as a steering force). With such a power steering device, even a vehicle that requires a large steering force, such as a large vehicle or a vehicle using a wide tire for the steering wheel, can perform steering with a small steering force, and the so-called steering wheel weight is increased. Is eliminated.

As this power steering device, a hydraulic power steering device that assists steering by hydraulic pressure using a hydraulic cylinder mechanism is generally used. In this hydraulic power steering device, a hydraulic pump is also equipped with an engine. And those driven by an electric motor. In addition, an electric power steering device that assists steering by an electric motor has been developed.

[0004] By the way, such a power steering apparatus has been developed in which the steering assist amount is made variable. For example, in the case of an engine pump type hydraulic pump, a valve is interposed in a hydraulic system and the assist amount is adjusted by adjusting the valve.In the case of an electric hydraulic pump, the output of the electric motor itself is adjusted. The amount of assist is adjusted.

In such a vehicle, for example, the steering assist amount is increased in accordance with the vehicle speed so that the steering wheel (handle) can be operated lightly at low speeds, and the steering wheel becomes more stable as the vehicle speed becomes higher at medium and high speeds. In order to reduce the steering assist amount, a vehicle speed-sensitive power steering device has been developed.

In the case where the steering assist amount is variable as described above, it is preferable that the assist amount is adjusted so as to change regularly according to the degree of request for the steering assist, for example, by responding to the vehicle speed as described above. Conversely, if the adjustment of the assist amount is irregular, the driver will feel uncomfortable at the time of steering.

[0007]

The driver may be drowsy during driving due to fatigue or the like. In such a case, it is originally desired that the driver take a proper rest, but the driver should be alerted if the driver suddenly falls asleep or does not notice the accumulation of fatigue. If it can do so, operation of a vehicle can be performed more safely.

That is, when the arousal level of the driver decreases, it is conceivable to call attention to the driver to notice the decrease in the arousal level. In this case, the means for detecting the arousal level and the means for calling attention are considered. Will be needed. Among these, a means of calling attention may be made by using a sound such as a warning buzzer.However, if such a dedicated warning buzzer must be provided, the cost will increase, and occupants other than the driver will have to pay attention. May be annoying.

[0009] On the other hand, it is conceivable that the assist amount of the power steering mechanism is changed irregularly to give the driver a sense of incongruity, thereby causing the driver to recognize a decrease in the arousal level. SUMMARY OF THE INVENTION The present invention has been made from the above-described viewpoint, and in a vehicle having a power steering mechanism with a variable assist amount, a driver steers to a driver via a steering wheel when the driver's arousal level decreases.
Steering assistance in the forward and reverse directions of the ring wheel
It is an object of the present invention to provide a vehicle with a steering assist device that allows the driver to be alerted by alternately experiencing the amount .

[0010]

Means for Solving the Problems] Therefore, the steering assist system with a vehicle of the present invention, a steering wheel input artificial steering force, is interposed between the steering wheel side and the steering helm side A steering force transmission system for steering the steered wheels at an angle corresponding to the state of the steering wheel;
It is attached to該操Kajiryoku transmission system, and equipped with a power steering mechanism for assisting the steering force corresponding to the steering state when the input of the artificial steering force and monitor, a steering force assist amount by the power steering mechanism In a vehicle equipped with a variable assist amount variable mechanism, based on detection information from an awakening degree detecting unit that detects an awakening degree of an operator who inputs the artificial steering force, when alertness of the operator is in the normal state, running normal control to experience a stable steering force assist amount corresponding to the steering state in該操author at the input of the artificial steering force together
In addition, when the degree of awakening of the operator is in a reduced state, the input of the artificial steering force is performed through the steering wheel.
The operator is prompted to forward or reverse the steering wheel.
Awakening level improvement control that allows the driver to alternately sense the steering assist amount
And a sensation steering force control means for performing the following .

[0011]

In the above-described vehicle with a steering assist device according to the present invention, when an artificial steering force is input from the steering wheel, the vehicle is steered by a steering force transmission system interposed between the steering wheel and the steered wheels. The wheels are steered at an angle corresponding to the state of the steering wheel.

[0012] At this time, the steering force through the power steering mechanism is assisted, at the same time, the operator of alertness to enter the artificial steering force is detected by the alertness detection means, based on this detection information, experience By the steering force control means
The assist amount variable mechanism is controlled to change the steering force assist amount of the power steering mechanism. In other words, experience
The control of the assist amount variable mechanism by the steering force control means is based on the detection information from the arousal level detection means, and when the arousal level of the operator is in the normal state, a stable state corresponding to the steering state when an artificial steering force is input. Steering force to the operator
The normal control for the user to experience is realized .

When the awakening degree of the operator is low, the steering wheel is turned when an artificial steering force is input.
Forward and reverse steering wheel to the operator via
Awakening degree improvement control for alternately sensing the steering assist amount in the turning direction is performed . In the awakening degree improvement control, an irregular change in the steering assist amount is sensed as a feeling of steering discomfort, and the awakening degree can be increased.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A vehicle with a steering assist device according to an embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a hydraulic circuit diagram schematically showing the hydraulic system, and FIG. FIG. 3 is a cross-sectional view schematically showing a configuration of a main part thereof, FIG. 3 is a cross-sectional view showing S1-S1 in FIG. 2, and FIG. -S2 sectional view, FIG. 5 is a sectional view schematically showing the operation state, FIG. 6 is a schematic view showing the operation state, FIG. 7 is a flowchart for explaining the operation, and FIGS. FIG. 11 is a hydraulic circuit diagram schematically showing a modified example of the hydraulic system.

As shown in FIG. 1, a power steering mechanism 4 is provided in a steering force transmission system 3 provided from a steering wheel 1 of a vehicle to steered wheels (not shown). When a steering force is input to the steering wheel 1, the steering force is assisted according to the steering state of the vehicle.

The power steering mechanism 4 of this embodiment
Is configured as a hydraulic power steering mechanism that assists a steering force with a hydraulic pressure, and supplies a hydraulic oil of a predetermined hydraulic pressure to a hydraulic cylinder 4A of the power steering mechanism 4 so that an operator (or a driver) can perform steering. The power can be reduced. This steering force transmission system 3
Is constituted by a torsion bar 109, a steering gear 3A, an input shaft 111, and an output shaft 105a, as shown in FIG.

As shown in FIG. 1, a steering shaft 1A is connected to the steering wheel 1. The steering shaft 1A is connected to an input shaft 1 as shown in FIG.
11 are connected. This input shaft 111
Is formed in a hollow shape as shown in FIG. 2, and a torsion bar 109 is provided on the same axis as the input shaft 111 inside.

The torsion bar 109 is fixed to the input shaft 111 at its upper end.
The lower end is connected to the output shaft 105a. As shown in FIG. 2, the rack 2 and a pinion 105 are provided in the steering gear 3A, and the pinion 105 is connected to the output shaft 105.
a. Thus, the rack 2 moves according to the rotation of the output shaft 105a.

That is, when a steering force is input to the steering wheel 1, the steering force is applied to the steering shaft 1.
The steering force is transmitted to the torsion bar 109 via the A and the input shaft 111. The torsion bar 109 transmits the steering force to the pinion 105 while being twisted. By the way, as shown in FIG. 1, this vehicle includes an oil pump 23 driven by an electric motor 22.
The oil pump 23 sucks hydraulic oil from a reservoir tank (or oil reservoir) 11.

The electric motor 22 is used for a steering operation to be described later.
The power supply is adjusted in accordance with a command signal from the controller unit 33 as a force control means, the operation state is controlled, and the hydraulic pressure of the hydraulic oil can be controlled. The hydraulic oil discharged from the oil pump 23 is then branched in two directions.
One oil passage is connected to the power steering mechanism 4. Thereby, the hydraulic oil is supplied to the hydraulic cylinder 4A.

Here, the hydraulic path of the power steering mechanism 4 will be described in detail. As shown in FIG. 2, a rotary valve 116 is provided in a housing 114 of the steering gear 3A. This rotary valve 1
Reference numeral 16 denotes a cylindrical outer valve 117 rotatable in the housing 114 and a cylindrical inner valve 118 provided integrally with the input shaft 111.

When the torsion bar 109 is twisted by the steering force input from the steering wheel 1, the outer valve 117 is rotated.
Relative displacement occurs between the outer valve 117 and the inner valve 118, and the hydraulic oil is supplied to the hydraulic cylinder 4A in accordance with the relative displacement between the outer valve 117 and the inner valve 118.

Further, as shown in FIG.
17 has an inflow port 117 a, which communicates with an inflow port 119 provided in the housing 103.
Similarly, the outflow port 11 is connected to the inner valve 118.
8a is formed and the outlet 1 provided in the housing 3
20. An output port (not shown) is formed in the outer valve 117, and communicates with a pair of output port portions 121 and 122 provided in the housing 103. The output ports 121 and 122 are connected to a hydraulic cylinder 4A (see FIG. 1) through an oil passage.

A part of the rack 2 in the hydraulic cylinder 4A is
It functions as a piston rod and is slidable in the hydraulic cylinder 4A. In addition, a piston is provided in a part of the piston rod, and by this piston,
Hydraulic chambers are formed on both longitudinal sides (left and right) in the hydraulic cylinder 4A. As shown in FIG. 1, a pair of input ports 126 and 127 are provided in the hydraulic cylinder 4A so as to communicate with the left and right hydraulic chambers, respectively. 12
8 and 129 are connected to the output port units 121 and 122.

The inlet 119 of the housing 103 of the steering gear 3A shown in FIGS. 1 and 2 is connected to the oil pump 23 shown in FIG. 1, and the outlet 120 of the housing 103 is connected to the oil reservoir 11. Thus, a hydraulic circuit of the hydraulic cylinder 4A is configured. When the outer valve 117 and the inner valve 118 of the rotary valve 116 are relatively displaced, a hydraulic pressure according to the steering force and the steering direction is supplied from the rotary valve 116 to a hydraulic chamber in the hydraulic cylinder 4A. Thus, the steered wheels are steered while being assisted by hydraulic pressure.

As shown in FIG. 1, the power steering mechanism 4 is provided with a variable assist amount mechanism 31 for adjusting the amount of assist from the power steering mechanism 4. Here, the assist amount variable mechanism 31
Is an electronically controlled power steering control valve (EPS)
The hydraulic pressure of the hydraulic cylinder 4A is adjusted through the EPS valve.

In this electronically controlled power steering, for example, the operation of an EPS valve or the like is electronically controlled by an ECU (electronic control unit) (not shown) based on information detected by a vehicle speed sensor or the like, and the steering assist is controlled. The amount can be adjusted. Further, the steering force transmission system 3 of the vehicle is provided with a reaction force generating means 30 in addition to the EPS valve. By adjusting the reaction force generating means 30,
The assist amount by the assist amount variable mechanism 31 (that is, the EPS valve) can be controlled.

The reaction force generating means 30 is constituted, for example, as follows. As shown in FIG. 2, the lower end 1 of the input shaft 111 in the power steering mechanism 4
37, the input shaft 111 is connected to the torsion bar 1
It is in a state of being extended downward along the axial direction of 09. The periphery of the lower end 137 is stored in the casing 103, and a circular chamber 147 is formed between the lower end 137 and the casing 103. Further, inside the chamber 147, a large-diameter portion 138 integrally connected to the output shaft 105a is rotatably accommodated.

The large diameter portion 138 is provided with the rotary valve 116.
The outer valve 117 is connected via a pin 136. An inner sleeve 139 is fitted over the entire outer peripheral surface of the large-diameter portion 138.
9 and the casing 103, the outer sleeve 14
0 is rotatably fitted. As shown in FIGS. 3 and 4, inside the large-diameter portion 138, a flat concave-shaped chamber 1 is provided.
41 are formed.

The lower end 1 covered with the large diameter portion 138
The plate 37 has plate-shaped protrusions (pressed portions) 142 that protrude outward in the radial direction, respectively. Each of the overhang portions 142 is formed to have an outer shape smaller than the length and width of the chamber 141, and the overhang portion 142 is loosely fitted concentrically into the chamber 141. Further, the gap between the plate-shaped overhang portion 142 and the flat chamber 141 is determined to have a dimension in which a region necessary for compensating the operating angle of the rotary valve 116 can be set.
Is twisted within a predetermined angle range.

Four circular holes 143 are formed symmetrically on both sides of the chamber 141 so as to be connected in series with the overhang 142 interposed therebetween. Each of the holes 143 has a plunger (pressing element) 14.
4a and 144b are slidably fitted in the axial direction.
A projection 142a is formed at the center of the tip of each of the plungers 144a and 144b, and the projection 142a is pressed by the projection 142a.

Further, a hole surrounded by the rear end surfaces of the plungers 144a and 144b and the inner sleeve 139 has:
Hydraulic chambers 145 and 146 are formed respectively. Hereinafter, of these four symmetric hydraulic chambers 145 and 146,
Two chambers on the clockwise rear side with respect to the chamber 141 are referred to as a first hydraulic chamber 145, and two on the clockwise front side with respect to the chamber 141 are referred to as a second hydraulic chamber 146.

As shown in FIG. 2, a first annular oil passage 148 is provided above the outer peripheral surface of the inner sleeve 139, and a second annular oil passage 149 is provided below the outer peripheral surface of the inner sleeve 139. Is provided. As shown in FIG. 3, a first hole 150 a is provided at a position corresponding to the first hydraulic chamber 145 of the inner sleeve 139, and the first annular oil passage 148 is provided at each of the first holes. It communicates with two first hydraulic chambers 145 via 150a. Similarly, as shown in FIG.
At the position corresponding to the hydraulic chamber 146,
50b is provided, and the second annular oil passage 149 communicates with the two second hydraulic chambers 146 via the respective second holes 150b.

Further, as shown in FIG. 2, a first annular oil passage 151 is provided at an upper portion of the outer peripheral surface of the outer sleeve 140, and a second annular oil passage 152 is provided at a lower portion of the outer peripheral surface of the outer sleeve 140. Have been. Note that reference numeral 15 in FIG.
Reference numeral 3 denotes an O-ring for sealing an oil passage. As shown in FIGS. 3 and 4, the first annular oil passage 151 of the outer sleeve 140 is connected to the first inlet / outlet 1 formed in the casing 103.
54, the second annular oil passage 1 of the outer sleeve 140.
52 is a second inlet / outlet 155 formed in the casing 103
Is in communication with

The outer sleeve 140 has the first communication hole 1
61, 161 are provided.
1, 161 through the first annular oil passage 148 of the inner sleeve 139 and the first annular oil passage 15 of the outer sleeve 140.
1 communicates with it. The outer sleeve 140 is also provided with second communication holes 162 and 162, and the second annular oil passage 149 of the inner sleeve 139 and the second communication hole 162 of the outer sleeve 140 are provided through the second communication holes 162 and 162. The two annular oil passages 152 communicate with each other.

Further, the vehicle has a mode switching valve 8 for controlling the operation state of the reaction force generating means 30.
The other oil passage of the oil passage branched in two directions from the oil pump 23 is connected to the mode switching valve 8. By controlling the mode switching valve 8, the reaction force generating means 30 is controlled.

The mode switching valve 8 is configured as, for example, a solenoid valve. Normally, the valve is closed and brought into a drain state by the balance between the biasing forces of the left and right return springs 16, 16. And
The mode switching valve 8 is configured such that the valve 8 is driven in the left-right direction in the figure based on a control signal from a controller unit 33 described later, whereby the required hydraulic oil is supplied to the reaction force generating means 30. It is supposed to be.

Various sensors are connected to the controller unit 33, and the operation of the electric motor 22 and the mode switching valve 8 is controlled based on information from these sensors. The controller unit 33 includes the stroke sensor 20, the vehicle speed detecting means 34, the engine speed detecting means 35, the steering information detecting means 36, and the awakening degree detecting means 37 as shown in FIG.
And are connected.

The arousal level detection means 37 is a sensor for detecting the arousal state of the driver, and calculates the arousal level (that is, for example, whether or not he / she is dozing) from the driver's heart rate or the like. Then, this is output to the controller unit 33. Further, for example, Japanese Patent Application Laid-Open Nos. 63-142478 and 3-156310
However, the awakening degree of the driver can be detected by using a technique for recognizing and detecting a white line disclosed in Japanese Patent Application Laid-Open No. H11-157572.

When such a white line recognition device is used, if the vehicle strays more than necessary and changes the course across the road white line, it can be determined that the driver's awakening degree is low. Further, when such a white line recognition device is linked with the turn signal switch, and the turn signal switch is OFF (that is, without activating the turn signal) and crosses the road white line more than a predetermined number of times within a predetermined time, this The awakening degree of the driver may be determined according to the number of times the vehicle crosses the white line.

Then, in the controller unit 33,
When it is determined that the driver's arousal level is low based on the information of the arousal level detection means 37, the mode switching valve 8 is adjusted, and the steering force is changed by the reaction force generation means 30. . That is, by driving the mode switching valve 8 and supplying the operating oil to the reaction force generating means 30, the steering force is positively changed, and the driver is alerted. As a result, the change in the steering feeling is transmitted to the driver, and the driver's arousal level can be improved.

The stroke sensor 20 is connected to the rack 2
And detects the stroke of the rack 2 during steering and outputs it to the controller unit 33. Further, the steering information detecting means 36 detects, for example, a steering angle and a steering force input to the steering wheel 1 and outputs the detected steering force to the controller unit 33.

Since the vehicle with the steering assist device according to one embodiment of the present invention is configured as described above, the running state of the vehicle is detected by the vehicle speed detecting means 34 and the engine speed detecting means 35. The steering state is detected by the stroke sensor 20 and the steering information detecting means 36. In addition, the awakening degree detecting means 37 detects the awakening degree of the driver. The controller unit 33 controls the assisting force of the power steering mechanism 4 based on the information.

If the driver's arousal level is low based on the detection information from the arousal level detection means 37, it is determined that the driver is dozing, and the power steering assist force is controlled to give a warning to the driver. At this time, whether to give a warning to the driver is determined according to the flowchart shown in FIG.

That is, first, the controller 33 determines the operating state of the vehicle based on information from the vehicle speed detecting means 34, the engine speed detecting means 35, and the steering information detecting means 36. Then, the controller 33 determines whether or not the driver can be warned according to the driving state of the vehicle (step S1). That is, since the steering assist device warns by the assist amount control, it is determined whether or not the assist amount control can be performed. Specifically, it can be determined that a warning is possible when there is a steering input, and it is determined whether or not the driver can be warned based on information of the steering angle sensor and the like.

If it is determined in step S1 that no warning can be given to the driver, that is, if it is determined that there is no steering input, the process returns. If it is determined in step S1 that a warning is possible, that is, it is determined that there is a steering input, it is determined whether or not the arousal level has decreased based on the detection information from the arousal level detection unit 37 (step S1).
2). Then, for example, by monitoring the driver's heart rate or detecting the relative positional relationship between the vehicle and the white line, it is inferred that the arousal level has decreased.

At this time, if it is determined that the arousal level of the driver has decreased, in step S3, arousal level improvement control is performed to change the assist force of the power steering mechanism 4 irregularly (randomly). It is. This sense
The arousal level improvement control is, specifically, the steering wheel
Exchange the steering assist amount in the forward and reverse directions of wheel 1.
It makes them feel each other. Further, in step S2, if the arousal level of the driver is not decreased, dry
Normal control as to experience a stable assist power is performed server.

At this time, in step S4,
Based on the information from the stroke sensor 20, it is determined whether or not it is necessary to increase the number of cuts. This determination is performed using, for example, a white line recognition system, as in step S1. Then, when it is determined that additional turning is necessary, a control signal is output from the controller unit 33 so as to increase the assisting force of the power steering mechanism 4 in step S5.

If it is determined in step S4 that no further turning is necessary, a control signal is output from the controller unit 33 so as to reduce the assisting force of the power steering mechanism 4 in step S6.
Then, the assist force of the power steering mechanism 4 is controlled based on a control signal from the controller unit 33.

When it is determined that the awakening degree improvement control is to be performed, the controller unit 33 controls the electric motor 22 and the mode control valve 8, and supplies the working oil to the reaction force generating means 30. The state of the action of the hydraulic pressure on the first and second hydraulic chambers 145 and 146 in the reaction force generating means 30 will be described with reference to FIGS.
FIGS. 5A, 5B and 5C show the first and second hydraulic chambers 1.
45, 146, the state of action of the hydraulic pressure, FIG.
(B) and (c) show the plunger 144 corresponding to FIG.
a and 144b are schematically illustrated.

When the hydraulic pressure from the oil pump 23 is supplied to the first hydraulic chamber 145, the plunger 144a presses the overhang portion 142 as shown in FIGS. Then, for example, a torsional moment in the normal rotation direction (right direction) of the rotary valve 116 is generated to slightly increase the operating angle of the rotary valve 116, for example.

As shown in FIGS. 5 (b) and 6 (b), when hydraulic oil from the oil pump 133 is supplied to the second hydraulic chamber 146, the plunger 144b presses the overhang portion 142, and the torsion bar At 109, for example, a torsional moment in the reverse rotation direction (left direction) of the rotary valve 116 is generated. When the first and second control valves 158 and 159 are operated, as shown in FIGS. 5 (c) and 6 (c),
The pressure oil from the oil pump 133 is supplied to the first and second hydraulic chambers 1
45, 146 and the plungers 144a, 144
b presses the overhang 142 from both sides. In this state, the equivalent rigidity of the torsion bar 109 is enhanced, and, for example, a sense of response and a sense of stability near the neutral position of the handle 113 can be increased.

As described above, the switching operation of the mode switching valve 8 generates a torsional moment independently of the torsion bar 109. Thus, for example, the steering force can be increased with respect to the steering input from the steering wheel 1, and the steering feeling changes. At this time, the electric motor 22 and the mode control valve 8 are connected by the controller unit 33, for example, as shown in FIG.
Is controlled according to the characteristics shown in FIG. FIG.
The horizontal axis of (a) is time t, and the vertical axis is the ratio of the assist force to the steering force.

As a result, the driver's steering force Hf and steering angle Ha change randomly as shown in FIG. 8B.
Therefore, when the assist force is changed irregularly in this manner, the assist force is transmitted to the driver via the steering wheel 1, and the steering wheel 1 is transmitted to the driver.
Experience alternate steering assist amounts in the forward and reverse directions
And, for example, as shown in FIG.
Due to the change in the steering force Hf, the heart rate of the driver increases, and the awakening degree of the driver can be improved.

This makes it possible to prevent falling asleep during driving. When it is determined that the steering angle return control is to be performed, for example, FIG.
The assist force is reduced by the characteristics shown in FIG. At this time, for example, the mode control valve 8 is driven to generate a reaction force against the steering force by the reaction force generation means 30 to reduce the assist force.

When the assisting force is reduced in this manner, the steering force borne by the driver increases, so that the steering angle Ha is equivalently reduced as shown in FIG. When it is determined that the steering angle turning control is to be performed, the assist force of the power steering mechanism 4 is increased in accordance with, for example, the characteristic shown in FIG.

When the assisting force is increased in this manner, the steering force borne by the driver is reduced, so that the steering wheel 1 can be steered with a light force, as shown in FIG. Equivalently, the steering angle Ha
Is increased, and the steering is turned further. As described above, when the driver's awakening degree is normal, the power steering mechanism 4
By adjusting the assist force of the steering wheel, it is possible to equivalently perform turning control and turning-back control, and positively control the steering angle.

When the degree of awakening of the driver is low, the assist force of the power steering mechanism 4 becomes irregular by supplying a random operating oil pressure to the reaction force generating means 30, and this causes the steering wheel 1 Transmitted to the driver. The driver can recognize that the awakening degree is low due to the irregular change in the steering force. This itself will improve the driver's arousal level, but even if the driver recognizes a decrease in his or her own arousal level, if the arousal level does not improve enough to drive the vehicle,
Drivers should take their own rest. Needless to say, the stimulus that changes the steering force irregularly can be expected to have the effect of improving the driver's arousal level sufficiently to continue driving. In this case, driving can be continued.

The oil pump 23 may be directly driven by the engine 9 as shown in FIG. In this case, since the discharge pressure of the hydraulic oil from the oil pump 23 depends on the rotation speed of the engine 9, a relief valve 13 for adjusting the hydraulic oil to a predetermined oil pressure is provided downstream of the oil pump 23. I have.

The relief valve 13 is controlled by a controller unit 33. When hydraulic oil higher than a predetermined oil pressure is supplied to the mode switching valve 8 and an EPS valve (not shown), the valve is opened. Is opened and the hydraulic oil returns to the reservoir tank 11. The relief valve 13 is configured as a solenoid valve operated by a solenoid 14, similarly to the mode switching valve 8.
By the urging force of No. 6, the valve is pressed to the left in the drawing, and the valve is closed.

Then, based on a control signal from the controller unit 33, the valve body is driven rightward in the figure against the return spring 16 by the solenoid 14 to open in a drain state. When the hydraulic oil is pressurized by the engine 9 in this manner, the hydraulic oil can be mounted on a vehicle at low cost and in a small space.

[0062]

As described above in detail, according to the vehicle with the steering assist device of the present invention, the steering wheel to which the artificial steering force is input, and the steering wheel side and the steering wheel are connected. A steering force transmission system interposed between the steering wheels to steer the steered wheels at an angle corresponding to the state of the steering wheel;
An assist which is attached to the steering force transmission system and which assists a steering force in response to a steering state when the artificial steering force is input, and which can change a steering force assist amount by the power steering mechanism; A variable amount mechanism, and an arousal level detecting means for detecting the arousal level of the operator who inputs the artificial steering force, and based on the detection information from the arousal level detecting means, the awakening of the operator when degree is in normal state, the on input of the artificial steering force
Stable steering force assist amount corresponding to the steering state for the operator
And executes the normal control to experience, when awareness of the該操authors reduction state, the stearyl to該操author through the steering wheel when entering the artificial steering force
Steering assistance in the forward and reverse directions of the aligning wheel
Execute arousal level improvement control to sense the amount of
With the configuration in which the sensible steering force control means is provided, in the normal control, a stable steering force assist amount corresponding to the steering state is exhibited, and in the wakefulness improvement control, the wakefulness of the driver can be improved. Thereby, it is possible to prevent the driver from falling asleep during driving.

Further, it can be constructed using a conventional power steering mechanism, and can be installed on a vehicle at low cost and in a small space.

[Brief description of the drawings]

FIG. 1 is a hydraulic circuit diagram schematically showing a hydraulic system in a vehicle with a steering assist device as one embodiment of the present invention.

FIG. 2 is a cross-sectional view schematically showing a configuration of a main part of a vehicle with a steering assist device as one embodiment of the present invention.

3 is a cross-sectional view showing a configuration of a main part of a vehicle with a steering assist device as one embodiment of the present invention, and is a cross-sectional view taken along line S1-S1 in FIG. 2;

4 is a cross-sectional view showing a configuration of a main part of a vehicle with a steering assist device as one embodiment of the present invention, and is a cross-sectional view taken along line S2-S2 in FIG. 2;

FIG. 5 is a cross-sectional view schematically showing an operation state of the vehicle with a steering assist device as one embodiment of the present invention.

FIG. 6 is a schematic diagram showing an operation state of a vehicle with a steering assist device as one embodiment of the present invention.

FIG. 7 is a flowchart illustrating an operation of the vehicle with a steering assist device according to one embodiment of the present invention.

FIG. 8 is a characteristic diagram for explaining the operation of the vehicle with a steering assist device as one embodiment of the present invention.

FIG. 9 is a characteristic diagram for explaining the operation of the vehicle with a steering assist device as one embodiment of the present invention.

FIG. 10 is a characteristic diagram for explaining an operation in a vehicle with a steering assist device as one embodiment of the present invention.

FIG. 11 is a hydraulic circuit diagram schematically showing a modified example of a hydraulic system in a vehicle with a steering assist device as one embodiment of the present invention.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 steering wheel 1A steering shaft 2 rack 3 steering force transmission system 3A steering gear 4 power steering mechanism 4A hydraulic cylinder 8 mode switching valve 9 engine 11 reservoir tank 13 relief valve 16 return spring 20 stroke sensor 22 electric motor 23 oil pump 30 reaction force Generating means 31 Assist amount variable mechanism 33 Controller unit as sensible steering force control means 34 Vehicle speed detecting means 35 Engine speed detecting means 36 Steering information detecting means 37 Arousal degree detecting means 103 Housing 105 Pinion 105a Output shaft 109 Torsion bar 111 Input shaft 114 Housing 116 Rotary valve 117 Outer valve 117a Inflow port 118 Inner valve 18a Outflow port 119 Inflow port 120 Outflow port 121, 122 Output port section 126, 127 Input port section 128, 129 Flow path 136 Pin 137 Input shaft lower end section 138 Large diameter section 139 Inner sleeve 140 Outer sleeve 141, 147 Chamber 142 Overhang 142a Projection 143 Circular hole 144a, 144b Plunger (pressing element) 145, 146 Hydraulic chamber 148 First annular oil passage 149 Second annular oil passage 150a First hole passage 150b Second hole passage 151 First annular oil passage 152 Second Annular oil passage 153 O-ring 154 First inlet / outlet 155 Second inlet / outlet 161 First communication hole 162 Second communication hole

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Takahiro Maemura 5-33-8 Shiba, Minato-ku, Tokyo Inside Mitsubishi Motors Corporation (72) Inventor Tadao Tanaka 5-33-8 Shiba, Minato-ku, Tokyo No. Mitsubishi Motors Corporation (56) References JP-A-3-96439 (JP, A) JP-A-3-7675 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) ) B62D 6/00

Claims (1)

(57) [Claims] And the steering wheel input to 1. A artificial steering force to steer the interposed has been該操steering wheel angle that corresponds to the state of the steering wheel between the steering wheel side and the steering helm side a steering force transmission system,該操Kajiryoku is attached to the transmission system, the artificial steering force corresponding to the steering state on input and and a power steering mechanism for assisting the steering force and monitor, the power steering mechanism A vehicle provided with an assist amount variable mechanism capable of changing a steering force assist amount by means of an awakening degree detecting means for detecting an awakening degree of an operator who inputs the artificial steering force, and a detection from the awakening degree detecting means based on the information, when awareness of the該操authors of normal state, to experience a stable steering force assist amount corresponding to the steering state in該操author at the input of the artificial steering force And executes the normal control, when awareness of the該操authors reduction state, 該操author through the steering wheel when entering the artificial steering force
Operating the steering wheel in the forward and reverse directions.
Executes alertness improvement control that alternately senses the steering assist amount
A vehicle with a steering assist device, characterized in that the vehicle is provided with a sensible steering force control means.