JPH05164176A - Shock absorber for attitude control of vehicle - Google Patents

Abstract

PURPOSE:To increase the ability of attitude change restraint at the initial time of action by providing a damping force regulating valve that is in series with an orifice and conducts control in the direction of raising initial load based on an outside signal, restoring gradually initial load after its control. CONSTITUTION:In the case of a chock absorber equipped with an oil passage that passes through an orifice 22, in parallel with the oil passages of main vales 11, 13 for damping force generation, a damping force regulating valve 17 that is in series with the orifice 22 and conducts control in the direction of initial load being raised by means of an outside signal, is provided. As a result, when an outside signal for attitude control start is received, damping force generated by the damping force regulating valve 17 comes to be increased, and increased damping force having the valve characteristic of projecting upward from a microlow speed sphere at the initial time of action, is generated. Accordingly, the ability of a shock absorber 11 is remarkably increased, and travel stability can secured. Also, generated damping force is gradually restored to the former state after attitude control, so confortableness during control is secured, and the instability of operation due to throw up from the lower part or the like can also be removed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle attitude control shock absorber suitable for automatically controlling the attitude of a vehicle while the vehicle is running and ensuring steering stability.

[0002]

2. Description of the Related Art Rolling that occurs on a vehicle body due to a sudden steering wheel while the vehicle is running, nose dives and squats when the vehicle is suddenly started or stopped, or wobbling of the vehicle body when traveling at high speeds, etc. Significantly harm the
Not only will the driver and passengers feel uneasy, but it may also lead to a serious accident.

From such a point of view, attention has been focused on means for automatically controlling the posture while the vehicle is running to prevent the occurrence of the above-mentioned phenomenon.

FIG. 6 shows a known damping force adjustable shock absorber 1a that adjusts the damping force by changing the opening degree of the orifice that regulates the movement in the initial stage of operation, and the opening degree of the orifice of this shock absorber 1a is changed. , An example of means for controlling the attitude of the vehicle by controlling with an external signal,
For example, rolling that occurs when the vehicle speed and the steering wheel angular velocity exceed a certain value, a nose dive that occurs when the vehicle speed decelerates rapidly above a certain value, and conversely a squat during sudden acceleration when the vehicle speed is below a certain value. , And each state quantity that causes a change in vehicle behavior such as running instability that occurs during high-speed running at a certain speed or higher are sensed by the vehicle speed sensor 29, the steering wheel angular velocity sensor 30, the brake pressure sensor 31, the accelerator opening sensor 32, and the like. The controller 33 processes these pieces of information and transmits the information to the damping force adjusting actuator 34 of the shock absorber 1a so that the orifice opening of the shock absorber 1a is properly controlled and the vehicle posture change is controlled to be gentle.

[0005]

However, if such a damping force adjusting type shock absorber 1a with a variable orifice opening is used for controlling the attitude of the vehicle, the damping force characteristic diagram of FIG. 7 can be seen. In addition, since the variable range of the damping force in the low speed range becomes a so-called squared characteristic orifice region and exhibits a downwardly convex characteristic, the damping force generated at the initial stage of the movement at which the shock absorber 1 starts to move is sufficient. It is difficult to obtain a high height, and the effect of suppressing the vehicle posture is small.

This means that it is difficult for the driver and the passengers to feel that the posture control of the vehicle has been performed, and it is not possible to eliminate the anxiety of the driver and the passengers, but also to improve the running stability of the vehicle. It is not preferable from the aspect.

In addition to this, the damping force adjusting type shock absorber 1a of variable orifice opening type cannot take a high initial damping force when the behavior of the vehicle changes as described above, so that it has an effect of suppressing the vehicle attitude. To get enough,
It is necessary to continue the state of damping force control for a certain period of time, and during that time, the input from the road surface to the vehicle body becomes too strong and the riding comfort is impaired, and if there is a large thrust from below such as over a bump, Problems such as being transmitted to the vehicle body and impairing the steering stability will occur.

Therefore, an object of the present invention is to enhance the ability to suppress the posture change of the vehicle at the initial stage of the operation of the shock absorber and to make the driver and the occupant experience the posture control effect as a real feeling, thereby eliminating the anxiety. A shock absorber suitable for controlling the attitude of a vehicle, which is provided with a damping force adjusting device that can perform the above.

It is another object of the present invention to provide a vehicle attitude control device which can secure riding comfort and steering stability during the vehicle attitude control operation together with the use of the shock absorber.

[0010]

In order to achieve the above object, the present invention provides a shock absorber having an oil passage passing through an orifice in parallel with an oil passage of a main valve for generating a damping force. , A damping force adjustment valve that is controlled in the direction of increasing the initial load by an external signal is provided in series with the orifice, and the damping force generated by the damping force adjustment valve in the shock absorber is gradually reduced after the control operation to the original state. I added a means to return to.

[0011]

As a result, according to the present invention, when the external signal for starting the attitude control of the vehicle is received, the damping force generated by the damping force adjusting valve becomes high, and the damping force adjusting valve operates the shock absorber. A high damping force having an upwardly convex valve characteristic instead of a downwardly convex orifice characteristic is generated from the initial very low speed region.

Therefore, the ability of the shock absorber to suppress the change in the posture of the vehicle is remarkably enhanced, so that the running stability can be secured, and at the same time, the effect can be fully understood by the driver and the occupant to eliminate the anxiety.

Further, after the vehicle posture control described above, the damping force generated by the shock absorber is gradually returned to the original state without being kept in the control state for a certain period of time. Instability of maneuvering due to thrusting or the like can be eliminated.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings.

As shown in FIG. 1, a vehicle attitude control shock absorber 1 according to an embodiment of the present invention comprises a working cylinder 2 and an outer cylinder 3 which surrounds the working cylinder 2 and has an inner and outer double cylinder structure. Thus, the reservoir chamber 4 is defined between the working cylinder 2 and the outer cylinder 3.

A piston 5 is slidably inserted into the working cylinder 2, and the piston 5 divides the working cylinder 2 into an upper oil chamber 6 and a lower oil chamber 7, and at the same time, the piston 5 moves away from the piston 5. A piston rod 9 extends outward through a cap 8 that closes the upper ends of the working cylinder 2 and the outer cylinder 3.

The lower end of the working cylinder 2 has a base valve 1
It is blocked by 0, and this base valve 10 has
Only the pressure side main valve 11 that gives a resistance to the flow of oil from the lower oil chamber 7 toward the reservoir chamber 4 in the working cylinder 2 to generate a damping force, and conversely the flow of oil from the reservoir chamber 4 toward the lower oil chamber 7. Is provided with a check valve 12 for permitting the flow of the oil. Further, the piston 5 is provided with an expansion side main valve 13 that gives resistance to the flow of oil from the upper oil chamber 6 to the lower oil chamber 7 to generate a damping force. Conversely, a check valve 14 that allows only the flow of oil from the lower oil chamber 7 to the upper oil chamber 6 is provided.

The upper oil chamber 6 communicates with the reservoir chamber 4 from the oil passage 15 formed in the cap 8 through the oil passage pipe 16 and the damping portion forming the essential part of the present invention at the outlet portion of the oil passage pipe 16. A force adjustment valve 17 is provided.

The damping force adjusting valve 17 has an oil passage 18 communicating with the oil passage pipe 16 as seen in the detailed view of FIG.
A case 20 having an oil passage 19 opening to the reservoir chamber 4.
The oil passages 18 and 19 are connected to a valve chamber 21 formed in the lower portion of the case 20. In addition, the oil passage 19
An orifice 22 that limits the function of the damping force adjusting valve 17 to only the very low speed region of the shock absorber 1 is provided in the middle of the above.

In the valve chamber 21 of the case 20, the oil passage 2
The sheet member 24 having the number 3 and the push rod 25 slidably inserted in the case 20 are provided so as to face each other, and the oil passages 18 and 19 of the case 20 are the oil passages of the sheet member 24. Through 23.

Between the seat member 24 and the push rod 25, there is provided a leaf valve 26 whose rigidity is set lower than those of the pressure side and extension side main valves 11 and 13 in the shock absorber 1. 26 is
The seat member 24 and the push rod 25 are in a state in which the points of action of the leaf valve 26 on the leaf valve 26 are offset from each other and the initial load is zero.
It is sandwiched by the push rod 26.

A piezoelectric element 27 as an actuator is incorporated in the case 20 in contact with the push rod 25, and the piezoelectric element 27 expands in accordance with the magnitude of the voltage applied thereto and the push rod 25 is interposed therebetween. Press the leaf valve 26. As described above, in the leaf valve 26, the points of action of the seat member 24 and the push rod 25 on the leaf valve 26 are offset from each other, so that the initial load is increased as the piezoelectric element 27 expands.

Returning to FIG. 1, the control unit 28 for controlling the attitude of the vehicle has a vehicle speed sensor 29, a steering wheel angular velocity sensor 30, and a brake pressure sensor for sensing each state quantity that causes a behavior change of the vehicle, as in the conventional case. 31 and an accelerator opening sensor 32 (in addition, a lateral G sensor, a yaw rate sensor, a longitudinal G sensor, a shift position sensor, etc. may be used) and the like, and the damping force adjusting valve 17 in the shock absorber 1 by processing these information. Controller 33 which outputs a voltage signal to the piezoelectric element 27.

However, the controller 33 in this case is
Different from the conventional one, the piezoelectric element 2 outputs voltage signal as output.
After adding to 7, the output is gradually decreased and the logic is restored to the original state.

Although not shown, instead of the above logic, for example, a dashpot is provided in the push rod 25 in the damping force adjusting valve 17, and the return speed of the push rod 25 is regulated by this dashpot. May mechanically have the same effect.

The precursor of the vehicle behavior change sensed by each of the sensors 29 to 32 is controlled by the controller 33,
A voltage signal is applied to the piezoelectric element 27 of the damping force adjusting valve 17. The piezoelectric element 27 expands according to the magnitude of this voltage signal, and the expansion force of the piezoelectric element 27 plays a role of increasing the initial load of the leaf valve 26 through the push rod 25.

Therefore, according to the shock absorber 1 of the above embodiment, the rigidity of the leaf valve 26 in the damping force adjusting valve 17 is set lower than the rigidity of each of the compression side main valve 11 and the expansion side main valve 13. Therefore, during the extension operation in a very low speed range where the hydraulic pressure generated in the upper oil chamber 6 is relatively low, the oil in the upper oil chamber 6 can be transferred from the oil passage 15 to the oil passage 15 without opening the extension side main valve 13. While pushing the leaf valve 26 open through the oil passage 18 of the pipe 16 and the damping force adjusting valve 17 and the oil passage 23 of the seat member 24, the oil passage 19 is passed through the orifice 22 to the reservoir chamber 4 on the shock absorber 1 side. The oil in the reservoir chamber 4 is replenished into the lower oil chamber 7 through the check valve 12 of the base valve 10.

Similarly, during the compression operation in the low speed region where the generated oil pressure in the lower oil chamber 7 is low, the oil in the lower oil chamber 7 is not transferred to the piston 5 without opening the pressure side main valve 11.
Flowing through the check valve 14 to the upper oil chamber 6 and the oil corresponding to the invading volume of the piston rod 9 passes from the upper oil chamber 6 through the oil passage 15, the oil passage pipe 16 and the oil passages 18, 23. While pushing the leaf valve 26 open,
It flows from the oil passage 19 through the orifice 22 to the reservoir chamber 4.

Thus, in the very low speed range of the shock absorber 1, the generated damping force is set by the leaf valve 26 of the damping force adjusting valve 17 regardless of the expansion and compression operations.

When the speed of expansion and compression of the shock absorber 1 increases, the oil passage 19 of the damping force adjusting valve 17 increases.
The hydraulic characteristic of the upper oil chamber 6 or the lower oil chamber 7 of the shock absorber 1 suddenly rises due to the square characteristic effect due to the flow rate restriction of the orifice 22 provided in the middle of the The oil in the oil chamber 6 becomes the piston 5
The expansion side main valve 13 is pushed open to flow into the lower oil chamber 7. At this time, the expansion side main valve 13 generates a damping force during the expansion operation, and the oil corresponding to the withdrawal volume of the piston rod 9 Check valve 12 of valve 10
The oil in the lower oil chamber 7 that has been sucked into the lower oil chamber 7 through the through hole and has increased hydraulic pressure pushes the check valve 14 of the piston 5 open to flow into the upper oil chamber 6 and The oil corresponding to the invading volume of the rod 9 pushes open the pressure side main valve 11 of the base valve 10 from the lower oil chamber 7 and flows into the reservoir chamber 4. At this time, the pressure side main valve 11 generates a damping force during the compression operation. To do.

As described above, the damping force generated during the expansion and compression operations of the shock absorber 1 is set by the leaf valve 26 of the damping force adjusting valve 17 only in the very low speed range, and in the speed range higher than that, the damping force of the shock absorber 1 is set. The generated damping force is set by the expansion side or compression side main valves 13, 11.

On the other hand, when each sensor 29 to 31 of the control unit 28 senses a sign that the behavior of the vehicle will change, the signal is controlled by the controller 33 and a voltage is applied to the piezoelectric element 27 of the damping force adjusting valve 17 in the shock absorber 1. It is applied as a signal. The piezoelectric element 27 expands according to the magnitude of this voltage signal, bends the leaf valve 26 through the push rod 25, and increases the initial load of the leaf valve 26. The increase of the initial load of the leaf valve 26 is caused by the shock absorber 1 as described above.
Increase the damping force generated in the very low speed range.

Since the operation of the shock absorber 1 accompanying a change in the behavior of the vehicle always passes through a very low speed range,
When the damping force generated in this very low speed range becomes large as a valve characteristic, the effect of suppressing changes in vehicle behavior increases, the speed of initial vehicle posture change decreases, inertia decreases, and the total amount of change changes. decrease.

Although the control operation of the leaf valve 26 is immediately released, the initial load of the leaf valve 26 is
Logic of controller 33 (or push rod 2
The function of the dashpot provided in 5) gradually shifts to the original state.

Thus, the damping force characteristic of the vehicle attitude control system according to this embodiment is as shown in FIG. 3, which not only increases the vehicle behavior suppressing effect but also reduces the influence of the road surface input during the control operation. The driving stability is ensured during that time.

FIGS. 4 and 5 show an example in which the above invention is applied to a single-cylinder type shock absorber 101. Such a single-cylinder type shock absorber 101, as is well known, enters a piston rod 109. As a compensating chamber for the volume, a gas chamber 104 corresponding to the reservoir chamber 4 in the embodiment of FIG. 1 is provided directly in the operating cylinder 102 by a free piston 103 and is extended from the pressure side main valve 111. The side main valve 113 is provided together with the piston 105 as seen in the detailed view of FIG.

Therefore, the damping force adjusting valve 1 for setting the damping force generated by the shock absorber 101 in a very low speed range.
In the case of this embodiment, the leaf valve 126 of No. 17 is a seat member 124 having an oil passage 123 fixed to the piston nut 120 and another slide valve 126 slidably inserted into the piston nut 120 leaving the oil passage 121. Sheet member 12
It is sandwiched between 5 and.

The seat members 124 and 125 are in contact with the outer circumference and the inner circumference of the leaf valve 126 in an offset state, and in this state, the leaf valve 126 moves from the oil passage 121 to the oil passage 123.
The inner circumference is deflected with respect to the oil flow toward the oil passage 12
With respect to the flow of oil from the oil passage 3 toward the oil passage 121, the outer circumference is bent to generate a damping force. Moreover, the initial load of the leaf valve 126 is zero in a normal state.

Although not shown in the drawing, the control unit for sensing a precursor of a change in vehicle behavior and generating a voltage signal corresponding thereto is the same as in the case of the previous embodiment, and receives this voltage signal. A piezoelectric element 127 that expands is provided in the piston rod 109, and the expansion force of the piezoelectric element pushes down the seat member 125 against a spring 135 that is stronger than the rigidity of the leaf valve 126.
Bend 6 to increase its initial load.

An orifice 122 for making the damping force generated by the shock absorber 101 in a very low speed range dependent on the leaf valve 126 is provided in the piston rod 109, and the upper oil chamber 106 in the working cylinder 102 is provided with this orifice 122. The lower oil chamber 107 communicates with the orifice 122 through the oil passage 115 formed between the piston rod 109 and the piezoelectric element 127 and the oil passages 121 and 123.

As a result, the leaf valve 126 for setting the damping force generated in the very low speed range is interposed in series with the orifice 122 in the oil passage connecting the upper oil chamber 106 and the lower oil chamber 107.

Therefore, according to the shock absorber 101 of this embodiment, as in the case of the previous embodiment, during the extension operation in the very low speed range in which the hydraulic pressure generated in the upper oil chamber 106 is relatively low, the extension side is extended. The oil in the upper oil chamber 106 flows from the oil passage 123 to the lower oil chamber 107 while bending the inner circumference of the leaf valve 126 from the orifice 122 through the oil passages 115 and 121 without opening the main valve 113.

Similarly, during the compression operation in a very low speed region where the generated oil pressure in the lower oil chamber 7 is low, the oil in the lower oil chamber 107 does not flow through the oil passage 123 without opening the pressure side main valve 111. It flows through the orifices 122 from the oil passages 121 and 125 to the upper oil chamber 106 while bending the outer periphery of the leaf valve 126.

Thus, in the very low speed range of the shock absorber 101, regardless of the expansion and compression operations,
The generated damping force is set by the leaf valve 126 of the damping force adjusting valve 117.

When the speed of expansion and compression of the shock absorber 101 is increased, the upper oil chamber 106 of the shock absorber 101 is generated due to the square characteristic effect due to the flow rate restriction of the orifice 122 in series with the leaf valve 126.
Alternatively, when the oil pressure in the lower oil chamber 107 rises sharply and the extension operation is performed, the oil in the upper oil chamber 106, which has increased the oil pressure, pushes the extension side main valve 113 of the piston 105 to open it and moves to the lower oil chamber 107. At this time, the expansion side main valve 113 generates a damping force at the time of extension operation, and at the time of reverse compression operation, the oil in the lower oil chamber 107 whose oil pressure has risen is
The pressure side main valve 111 of the piston 105 is pushed open to flow into the upper oil chamber 104, and at this time, the pressure side main valve 11
At 1, the damping force is generated during the compression operation.

As described above, the damping force generated during the expansion and compression operations of the shock absorber 101 is set by the leaf valve 126 of the damping force adjusting valve 117 only in the very low speed range, and in the higher speed range, the shock absorber 101 is set.
Expansion side main valve 113 or compression side main valve 11
At 1, the generated damping force is set.

Therefore, if each of the sensors of the control unit senses a sign that the behavior of the vehicle will change, this signal is controlled by the controller, converted into a voltage signal, and applied to the piezoelectric element 127 of the shock absorber 101 as a voltage. , Leaf valve 1 as in the previous embodiment
The initial load of 26 is increased and the damping force generated in the very low speed region is increased.

As a result, the shock absorber 101 of this embodiment can be constructed by forming a logic for gradually returning the voltage signal after control to the controller or providing a dashpot on the seat member 125.
Based on the above explanation, it can be easily understood that the shock absorber 1 shown in FIG.

[0049]

As described above, according to the present invention, not only can the ability to suppress changes in the posture of the vehicle be remarkably enhanced to improve running stability, but also the effect can be easily provided to the driver and passengers. You can experience and give a sense of security.

After controlling the posture change of the vehicle,
Since the control can be gradually returned to the original state without maintaining that state for a certain period of time, not only is the discomfort caused by the road surface input during control eliminated and the riding comfort is improved, but also due to pushing up from the road surface, etc. Maneuvering instability can also be eliminated.

[Brief description of drawings]

FIG. 1 is a diagram showing a vehicle attitude control device according to an embodiment of the present invention.

FIG. 2 is a detailed view showing an enlarged damping force generating valve which is a main part of FIG.

3 is a graph showing damping force characteristics according to the embodiment of FIG.

FIG. 4 is a diagram showing another embodiment of the present invention.

5 is a detailed view showing an enlarged damping force generating valve, which is a main part of FIG. 4. FIG.

FIG. 6 is a diagram showing a conventional vehicle attitude control device.

7 is a graph showing damping force characteristics of the conventional example of FIG.

[Explanation of symbols]

 1,1a, 101 Shock absorber 11,111 Pressure side main valve 13,113 Extension side main valve 15,115 Oil passage 17,117 Damping force adjustment valve 18 Oil passage 19 Oil passage 22,122 Orifice 23,123 Oil passage 26,126 Leaf valve 27,127 Piezoelectric element 28 Control unit 29 Vehicle speed sensor 30 Steering wheel angular velocity sensor 31 Brake pressure sensor 32 Accelerator opening sensor 33 Controller

Front page continuation (72) Hisashi Matsuda Hisashi Matsuda 2548 Tsuchida, Kani City, Gifu Prefecture Kayaba Industrial Co., Ltd.Gifu North Factory (72) Inventor Shizuka Sakai 2548, Tsuchida, Kani City Gifu Prefecture Kayaba Industrial Company Gifu North Factory

Claims (1)

[Claims] 1. A shock absorber having an oil passage passing through an orifice in parallel with an oil passage of a main valve for generating a damping force, the damping being controlled in a direction of increasing an initial load by an external signal in series with the orifice. A shock absorber for vehicle attitude control, comprising a force adjustment valve, and means for gradually reducing the initial load of the damping force adjustment valve to return it to its original state after controlling the damping force adjustment valve.