JPS641352B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a steering device for an automobile.

(Prior technology) Conventionally, damper devices have been installed between tie rods connected to the steering wheels and the vehicle body, with the aim of improving running stability when traveling straight at high speed and suppressing abnormal vibrations such as shimmy and jerking back. A steering device for an automobile is known that prevents wobbling of a steering wheel connected to a tie rod via a steering gear device by attenuating or absorbing disturbances received by the steering wheel using a damper device. Kaisho 57-57311
(see publication).

Such a steering device is certainly effective in suppressing the wobbling of the steering wheel, and can satisfy the above objectives. However, the above-mentioned steering device is difficult to use when the vehicle speed is high.
Since it only switches the damping force of the damper device depending on the low speed, it cannot respond to various driving conditions of the car. If the steering wheel is accelerated or decelerated to a position (switched to ``)'', a large external force applied to the steering wheel will be transmitted to the steering wheel via the steering system, causing a so-called steering wheel shock.

(Object of the Invention) The present invention was made to solve this problem, and an object of the present invention is to provide a steering device for an automobile that can effectively prevent steering wheel shock caused by acceleration and deceleration.

(Structure of the Invention) For this reason, the present invention detects the running state of the automobile, that is, whether it is running steadily or accelerating or decelerating. The basic idea is to reduce the damping force of the damper device, while increasing the damping force of the damper device during acceleration and deceleration, so that the shock applied to the steered wheels is alleviated and absorbed by the damper device, thereby preventing steering wheel shock. It is a feature.

That is, the steering device for an automobile according to the present invention includes a tie rod connected to a steering wheel, a steering wheel that operates the tie rod via a steering gear device, and a damper with variable damping force provided between the tie rod and the vehicle body. a device, an adjusting means for changing the damping force of the damper device, a driving state detecting means for detecting whether the driving state of the automobile is in a steady running state, and a damping force adjusted in response to the output of the driving state detecting means when the vehicle is running normally. and a controller that sends to the adjusting means a signal that increases the damping force during at least one of acceleration and deceleration.

(Effects of the Invention) According to the present invention, the damping force of the damper device can be changed according to the driving condition of the automobile, and the damping force can be changed during sudden starts or from a sudden start without impeding the steering operability during steady driving. It is possible to soften the steering wheel shock during sudden deceleration, and the structure can be advantageous as a countermeasure against torque steer when starting a front-wheel drive vehicle.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

As shown in FIG. 1, a knuckle 2 connected to a steering wheel 1 has an upper arm 2a connected to a damper 5 attached to a suspension tower 3 provided on the vehicle body via a rubber mount 4, and a lower arm 2b. is coupled via a rubber mount 8 to a lower arm 7 coupled to the vehicle body via a spindle 6. A knuckle 2 extends inward and diagonally laterally with respect to the axle (not shown) of the steering wheel 1.
A tie rod end 10 of a tie rod 9 extending in the left-right direction of the vehicle body is coupled to the intermediate arm 2c via a rubber mount 11.

Although the tie rod 9 is not specifically shown,
A rack is provided at a portion that passes through the inside of the gear housing 12a fixedly supported on the vehicle body side, and this rack is
A so-called steering gear device 12 is formed by meshing with a pinion 13 rotatably supported by a pinion bearing portion 12b of the gear housing 12a within the gear housing 12a. The above pinion 13
Although not specifically shown in the drawings, as is well known, the steering wheel is connected to a steering shaft which is rotated by a steering wheel (not shown) via a relay shaft, and the steering wheel is operated by the steering wheel. That is, when steering,
A steering mechanism is constructed in which the tie rod 9 is displaced to either the left or right by the pinion rack mechanism of the steering gear device 12, thereby changing the direction of the steered wheels 1.

As shown in FIGS. 1 and 2, on the vehicle body side, more specifically, between the mounting bracket 14 at the bottom of the suspension tower 3 and the tie rod 9, there is a
A damper device 15 with a variable damping force is installed in a slightly inclined state in the horizontal and vertical directions of the vehicle body.

This damper device 15 is equipped with a reversible step motor 16 at one end in the axial direction for making the damping force of the damper device 15 variable, and a mounting bracket 17 for the damper device 15 that also serves as a housing for the reversible step motor 16. is fixed to the mounting bracket 14 on the suspension tower 3 side by welding or the like, while a ring-shaped joint 18a provided at the tip of the damper rod 18 extending in the axial direction from the other end of the damper device 15 is attached to the tie rod 9. It is fitted onto the shaft portion 19a of a connecting fitting 19 having a fixed base, and is coupled to the tie rod 9 in a state in which it is prevented from coming off by a retaining washer 21 supported by a nut 20.

In addition, in FIGS. 1 and 2, 22, 2
A dust boot 2 seals between the gear housing 12a of the steering gear device 12 and the tie rod 9 by allowing the tie rod 9 to be displaced.

Next, the structure of the damper device 15 will be explained with reference to FIG.

As shown in FIG. 3, the damper device 15 has oil sealed inside a damper body 26 having a double cylinder structure consisting of an outer cylinder 24 and an inner cylinder 25, and a support rod 27 inside the inner cylinder 25. A piston assembly 28 supported at the tip is fitted in a relatively slidable manner.

The support rod 27 protrudes from the damper body 26 and is attached to the mounting bracket 17 by a mounting bracket 29.
It extends toward the reversible step motor 16 supported through the rubber mount 30 at its extended end and is supported by the mounting bracket 17. Note that 31 is a cover cylinder that is supported by the rubber mount 30 via a spacer 32 and covers the damper main body 26 and the support rod 27 from the outside.

A small-diameter rotary rod 33 is rotatably fitted into a through hole 27a provided along the central axis of the support rod 27.
is connected at one end to the output shaft of the reversible step motor 16 via a joint 34 so as to be interlocked with rotation. A rotary valve 36 having an L-shaped orifice passage 35 is formed at the other end of the rotary rod 33, which is formed to have a larger diameter. By driving, the orifice passage 35 and the corresponding communication passage 3 provided in the support rod 27 are opened.
The rotary valve 36 can be controlled to be switched between a position where 7 and 7 match (the illustrated position) and a position where the two do not communicate with each other.

By switching the rotary valve 36, the damping force of the damper device 15 is changed. That is, when the rotary valve 36 is rotated to the non-coincident (non-communicating) position, in other words, when the orifice passage 35 and the communication passage 37 do not coincide, the gap between the damper body 26 and the piston assembly 28 is The relative displacement is caused by the first and second orifice passages 3 provided to penetrate in the axial direction of the piston body 28a of the piston assembly 28.
8 or 39. As shown in FIG. 4, which is an enlarged view of the piston assembly 28, the first and second orifice passages 38 and 39, which are provided through the piston body 28a in the axial direction, are opened in opposite directions. First and second washer-shaped rings are formed with alternating ends and are supported via coil springs 42 and 43 by ring plates 40 and 41, respectively, which are fixedly supported at the ends of the support rod 27. Check valve 4
4, 45 to be opened and closed.
More specifically, as shown by arrow A in FIG.
When the damper main body 26 is displaced to the right in the figure, the oil pressure in the chamber 25B on the left side in the figure of the inner cylinder 25 increases, and this increase in oil pressure causes the second check valve 45 to open. , the second orifice passage 39 is opened, and the oil flows from the left chamber 25B to the right chamber 25A through the second orifice passage 39. Further, when the damper main body 26 is about to be displaced in the opposite direction to the direction A, the first check valve 4
4 is operated to open, and the first orifice passage 38 is opened. In any of the above cases, in the non-matching position of the rotary valve 36, the displacement of the damper body 26 is regulated only by either one of the first or second orifice passages 38, 39.
The displacement of the damper device 15 becomes slow, that is, the damping force of the damper device 15 becomes large.

On the other hand, when the orifice passage 35 of the rotary valve 36 and the communication passage 37 of the support rod 27 match as described above, the left and right chambers 25 in the inner cylinder 25
Since B and 25A are also communicated through the path between the orifice passage 35 and the communication passage 37, the amount of oil flowing between the two chambers 25A and 25B is significantly increased.
Therefore, the displacement of the damper body 26 becomes relatively fast, and the damping force of the damper device 15 is reduced.

As described above, the reversible step motor 16 and the rotary valve 36 supported by the rotary rod 33 constitute adjustment means for changing the damping force of the damper device 15.

Further, the increase or decrease in the internal volume of the inner cylinder 25 due to the relative displacement between the damper main body 26 and the support rod 27 as described above is caused by a cylinder made of an elastic material such as rubber whose both ends are hermetically fixed to the outer periphery of the inner cylinder 25. It is absorbed by the shaped diaphragm 46. Gas such as air is sealed between the diaphragm 46 and the inner cylinder 25. This diaphragm 46 is arranged so that the damper main body 26 is displaced in the right direction A in the figure, and the inner cylinder 2
5 is reduced by the support rod 27;
When oil equal to the amount decreased flows into the chamber 24A between the inner cylinder 25 and the outer cylinder 24 via the flow rate regulating valve 47 attached to the left end of the inner cylinder 25, the oil is contracted by the amount of the inflow. Conversely, when the damper main body 26 is displaced to the left in the figure, the oil stored in the chamber 24A between the inner cylinder 25 and the outer cylinder 24 is transferred to the inner cylinder 25 via the flow rate adjustment valve 47. Room 25B on the left side of
to accommodate the increase in the volume within the inner cylinder 25.

Next, a drive control circuit for the reversible step motor 16 will be explained.

As shown in FIG. 5, a reversible step motor 1
6 is equipped with a pair of arc-shaped movable contacts 48 and 49 that are linked to the rotation of the motor 16, and one movable contact 48 (on the left side in FIG. 5) has two fixed contacts 50 and 51. is provided, and one fixed contact 52 is provided for the other (right side) movable contact 49.
is provided. The above two fixed contacts 50,5
1, when the corresponding movable contact 48 is in the first rotational position A shown by the solid line in the figure, both fixed contacts 5
0 and 51 simultaneously contact the movable contact 48,
In the second rotational position B shown by the imaginary line in the figure, one fixed contact 50 does not contact the movable contact 48 and only contacts the other fixed contact 51. Note that the other movable contact 49 is configured to come into contact with the fixed contact 52 regardless of its rotational position.

The two fixed contacts 50 and 51 are connected to the drive power source 5
Switching contacts 54 connected to the positive and negative electrodes of No. 3, respectively.
They are connected to a common contact 54c of a first relay switch 54 having switches a and 54b via backflow prevention diodes 55 and 56 connected in parallel and in opposite directions, respectively. In addition, another fixed contact 52
is connected to a common contact 57c of a second relay switch 57 having switching contacts 57a and 57b connected to the positive and negative electrodes of the drive power source 53, respectively.

The relay coils 54X and 57X of the first and second relay switches 54 and 57 are controlled to be turned on and off by a relay control unit 58, which is configured, for example, as a part of a microcomputer. , the first and second relay switches 54,
57 is a common contact 54c of the first relay switch 54
is connected to the negative electrode of the drive power source 53, the common contact 57c of the second relay switch 57 is connected to the positive electrode of the drive power source 53 (the state shown), and from the state shown, the 1. 2nd
When the relay switches 54 and 57 are switched at the same time, the connection relation to the drive power source 53 is switched so as to be reversed.

The relay control unit 58 includes, for example, an acceleration sensor (G sensor) 59, which constitutes a driving state detection means for detecting whether the driving state of the automobile is steady driving or not.
It uses the output as input to determine whether the vehicle is running in a steady state or in an acceleration or deceleration state, and controls whether the two relay coils 54X and 57X are turned on or off according to the determination. That is, this relay control section 58 constitutes a controller that receives the output of the driving state detection means and issues a control signal to the adjusting means of the damper device 15 according to the driving state of the automobile.

Now, if the state shown in Fig. 5 corresponds to steady driving, then from that state the driver either depresses the accelerator pedal (not shown) greatly to shift to acceleration driving, or releases the accelerator pedal. When shifting to deceleration operation, the relay control unit 58
Based on changes in the output of the acceleration sensor 59, etc., it is determined that the current state is accelerating or decelerating, and the relay coils 54X, 57 of the first and second relay switches 54, 57 are activated.
Turn on X and turn on the first and second relay switches 54, 5.
7 at the same time. Therefore, the power supply path of the reversible step motor 16 is reversed, and the reversible step motor 16 operates in the counterclockwise AC direction, as shown in FIG.
When the movable contacts 48 and 49 are rotated to the second rotation position B shown by the imaginary line, one fixed contact 50 and the movable contact 48 come out of contact, and the reversible step motor 16 is disconnected. and stops at that position.

By one rotation of the reversible step motor 16 through a predetermined angle, the damper device 15 is brought into the state shown in FIG. 37 is switched from a matched state to a non-matched state, and as a result, the damping force of the damper device 15 is increased. That is, the damping force of the damper device 15 is switched from small to large.

Then, when the acceleration or deceleration operation described above shifts to steady running again, the output of the acceleration sensor 59 becomes almost zero, so the relay control section 58
The first and second relay switches 54 and 57 are switched to the state shown in FIG.
is rotated in the direction C of the hour hand in FIG. 5, one fixed contact 51 and the movable contact 48 come out of contact, the reversible step motor 16 is de-energized, and stops at that position. As a result, the orifice passage 35 of the rotary valve 36 and the communication passage 37 of the support rod 27 are communicated again, and the damping force of the damper device 15 is weakened again.

As described above, when the automobile is in a steady running state, the damping force of the damper device 15 provided between the vehicle body and the tie rod 9 is weakened, so that the steering wheel can be operated easily without being subjected to resistance from the damper device 15. I can do it. On the other hand, when the automobile is in an unsteady running state, that is, when accelerating or decelerating, the damping force of the damper device 15 is strengthened. and disturbances are attenuated or absorbed, making it possible to reliably soften the steering wheel shock during acceleration and deceleration, especially during sudden starts and decelerations.

In the above embodiment, the acceleration sensor 59 (acceleration/deceleration sensor) is used as the driving state detection means, but the rate of change in the throttle valve opening, the rate of change in the intake negative pressure, or the rate of change in the engine speed or vehicle speed In short, any means for detecting this may be used as long as it is capable of detecting whether or not the vehicle is in a steady running state.

In addition, the system detects the tread condition and determines whether the road is good or bad, and reduces the damping force of the damper device when driving steadily on a good road where little external force is applied to the steered wheels. It is also possible to increase the damping force of the damper device in other states where an external force is applied to the vehicle, ie, during acceleration and deceleration on a good road, and during steady acceleration and deceleration on a rough road.

[Brief explanation of drawings]

1 and 2 are a rear view and a plan view of essential parts of an automobile steering device according to an embodiment of the present invention, respectively, and FIG. 3 shows an example of the damper device shown in FIGS. 1 and 2. 4 is a partially enlarged sectional view of FIG. 3, and FIG. 5 is a circuit diagram showing a drive control circuit for a reversible step motor of the damper device. 1... Steering wheel, 9... Tie rod, 12... Steering gear device, 15... Damper device, 1
6... Reversible step motor, 33... Rotating rod, 36... Rotating valve, 54, 57... First, second
Relay switch, 58... Relay control section, 59...
…Acceleration sensor.

Claims (1)

[Claims] 1. A tie rod connected to a steering wheel, a steering wheel that operates the tie rod via a steering gear device, a damper device with a variable damping force installed between the tie rod and the vehicle body, and a damper device that changes the damping force of the damper device. an adjusting means, a driving state detecting means for detecting whether or not the vehicle is in a steady running state, and receiving an output from the driving state detecting means and transmitting a signal to reduce the damping force during steady running during acceleration and deceleration. A steering device for an automobile comprising a controller that issues a signal to an adjusting means to increase at least one damping force during driving.