JPH0939534A - Suspension device for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the vibration of a unsprung part while the primary vibration of a sprung part is suppressed by controlling the expansion/contraction stroke action speed of an actuator based on the signal from a vertical speed detector and an expansion/contraction stroke action speed detecting means. SOLUTION: The signal from a vertical acceleration sensor 40 is received by a vertical speed operating means. The signal from a stroke sensor 39 is received by a stroke speed operating means. A computing means compared these signal with each other, and controls a hydraulic pressure control valve 36 through a control means. The control means realizes the feedback control of the speed of the expansion/contraction stroke action of an actuator based on the stroke speed to be operated from the stroke of a shock absorber device 13 so that the vertical speed is computed from the vertical acceleration of a vehicle body 11 and a simulated expansion/contraction stroke action by an actuator 29 is added to the shock absorber device 13 in response thereto.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle suspension device, and more particularly to an active damper device using a shock absorber device.

[0002]

2. Description of the Related Art As one of suspensions mounted on buses, large trucks, etc., one using a shock absorber device as a damper is known. That is, as shown in FIG. 7, a shock absorber device 3 is provided between the vehicle body 1 as an unsprung part of the vehicle and the tire 2 as an unsprung part.

[0003]

By the way, the ordinary shock absorber device has a function of suppressing the vibration of the vehicle body, but if the damping force is made too strong, it has an adverse effect in the high frequency range, and the vehicle body resonance is sufficiently suppressed. I can't hold back. For this reason, conventionally, control for suppressing only the primary resonance (bouncing, pitching, rolling) of the vehicle body has been proposed (Preprint 862, Academic Lecture Meeting, Japan Society of Automotive Engineers of Japan).
See Showa 61-10).

This control is called a pseudo skyhook damper and has the following principle.

[0005]

[Equation 1]

As described above, in the conventional pseudo-skyhook damper, since the shock absorber device controls the damping force to be small during the vibration phase, it is not possible to sufficiently suppress the vibration on the tire side and during braking. However, there is a problem in that the grip force of the tire at the time of turning cannot be secured and the steering stability is impaired. Therefore, in view of the above conventional problems, the present invention suppresses primary resonance on a spring and suppresses vibration under a spring to improve riding comfort and steering stability. It is an issue.

[0007]

Therefore, according to the invention of claim 1, a shock absorber device is provided between a sprung portion and an unsprung portion of a vehicle, and the shock absorber device is attached to the sprung portion or the unsprung portion. An up-and-down speed detecting means for detecting an up-and-down speed on the spring is provided between an end portion and the sprung or unsprung actuator, and an up-and-down stroke operation speed of the actuator is detected. The drive of the actuator is controlled so as to control the expansion / contraction stroke operation speed of the actuator based on the expansion / contraction stroke operation speed detection means, and the detection signals output from the vertical speed detection means and the expansion / contraction stroke operation speed detection means. And a control means.

[0008]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 shows an air suspension device for one wheel of a vehicle, for example, a front left wheel. That is, in this figure, a shock absorber device 13 and a spring 14 are provided between the vehicle body 11 as an unsprung part of the vehicle and the tire 12 as an unsprung part.

In this case, the upper end portion of the shock absorber device 13 is connected to the vehicle body 11 side via the upper mounting bracket 15, and the lower end portion is connected to the axle 17 via the mounting portion 16.
And a bracket 18 of the vehicle body 11 are connected to a free end of a suspension arm 19. Also, the spring 1
4 is interposed and connected between the free ends of the vehicle body 11 and the suspension arm 19.

Here, the shock absorber device 13
An actuator 29 capable of expanding and contracting strokes is interposed between the mounting end portion of the vehicle body 11 or the tire 12 and the vehicle body 11 or the tire 12. The configuration of the shock absorber device 13 will be described in detail with reference to FIG. In this figure, the shock absorber device 13 is
It is composed of a lower shock absorber section 13A and an upper actuator / sensor section 13B.

The shock absorber portion 13A is composed of a pair of upper and lower cylindrical bodies 21, which constitute a shock absorber body.
22 is included. The lower cylinder 22 is the inner cylinder 2
2A and the outer cylinder 22B have an inner-outer double structure, and the peripheral wall of the inner cylinder 22A communicates with the inside of the inner cylinder 22A and the space between the inner cylinder 22A and the outer cylinder 22B. Are formed.

A viscous fluid 24 is filled in the inner cylinder 22A and in the space between the inner cylinder 22A and the outer cylinder 22B. A ring-shaped mounting portion 16 is fixed to the lower end of the lower cylindrical body 22. The upper cylindrical body 21 has a configuration in which the lower end surface is open, and is fitted and inserted into the outer peripheral surface of the upper end portion of the lower cylindrical body 22.

The cylindrical body 21 is provided with a rod 25 penetratingly fixed to the upper end wall thereof. The rod 25 includes a first rod 25A that extends vertically downward from the inner surface of the upper end wall of the cylindrical body 21 through the upper end wall of the cylindrical body 22 and into the inner cylinder 22A of the cylindrical body 22, and the upper end wall of the cylindrical body 21. The second rod 25B extends vertically upward from the outer surface.

The first rod 25A and the second rod 25
B is formed on the upper end portion of the first rod 25A, and the male screw portion 25b formed on the lower end portion of the second rod 25B is fitted to the screw portion 25a, and the nut 26 is tightened on the upper end surface of the cylindrical body 21. To be connected. A piston 27, which is arranged so as to partition the inside of the inner cylinder 22A into upper and lower chambers, is fitted to the lower end of the first rod 25A, and a valve spring 27c on the upper side of the piston 27 and a valve spring 27d on the lower side together with a nut. It is fastened and fixed by 28. The piston 27 has a communication hole 27 for communicating the upper and lower chambers with each other.
a and 27b are formed.

The actuator / sensor section 13B includes
The actuator 29 is included. The main body of the actuator 29 includes an upper small-diameter cylindrical portion 29A, a lower large-diameter cylindrical portion 29B, and an upper small-diameter cylindrical portion 2
9A and a male screw portion 29C that is integrally provided.

The small-diameter cylindrical portion 29A includes a ring-shaped cushion rubber 30 arranged on the lower surface of the upper mounting bracket 15, an upper mounting bracket 15 and a ring-shaped cushion rubber arranged on the upper surface of the upper mounting bracket 15. The male screw portion 29C that penetrates through the cushion rubber 31 and protrudes from the upper surface of the cushion rubber 31 has a nut 33 through a washer 32.
Is tightened.

The second rod 25B penetrating the lower end wall of the large diameter cylindrical portion 29B is inserted into both cylindrical portions 29A and 29B of the main body of the actuator 29, and the large diameter is formed on the outer peripheral surface of the second rod 25B. A piston 34 is provided so as to partition the inside of the cylindrical portion 29B into upper and lower chambers. Further, on the peripheral wall of the large-diameter cylindrical portion 29B, an oil supply / exhaust port 37 is provided in the upper chamber for supplying / discharging oil from the hydraulic pressure supply source 35 shown in FIG. An oil supply / exhaust port 38 for supplying and discharging oil from the hydraulic pressure supply source 35 via the hydraulic pressure control valve 36 is provided in the lower chamber.

A stroke sensor 39 for detecting the stroke of the actuator 29 based on the stroke of the second rod 25B is provided on the outer surface of the peripheral wall of the large diameter cylindrical portion 29B. Here, in the invention according to claim 1, an up-and-down speed detecting means for detecting an up-and-down speed on the spring,
Expansion / contraction stroke operation speed detection means for detecting the expansion / contraction stroke operation speed of the actuator, and control of the expansion / contraction stroke operation speed of the actuator based on the detection signals output from the vertical speed detection means and the expansion / contraction stroke operation speed detection means. In order to do so, a control means for controlling the drive of the actuator is provided.

Specifically, as shown in FIG. 1, the hydraulic control valve 36 described above is controlled by a control signal output from a control unit 41 containing a microcomputer. The control unit 41 includes a vehicle body 11
The vertical acceleration signal from the vertical acceleration sensor 40 and the stroke signal from the stroke sensor 39 are input to the control unit 41.
A control means for switching and controlling the hydraulic control valve 36 based on the vertical acceleration and the stroke is provided by software.

FIG. 3 is a detailed control block diagram. The vertical acceleration signal output from the vertical acceleration sensor 40 is input to the vertical speed calculating means B via the vertical acceleration input means A. The stroke signal output from the stroke sensor 39 is input to the stroke speed calculation means D via the stroke input means C. Further, the signals respectively output from the vertical speed calculation means B and the stroke speed calculation means D are input to the comparison means E, and this comparison means E
The signal output from the hydraulic control valve is input to the control means F of the hydraulic control valve, and the control means F controls the hydraulic control valve 36.

Next, the control contents of the actuator by the control unit 41 will be described with reference to the flow chart shown in FIG.

[0022]

[Equation 2]

In step 6, Δ obtained in step 5 is judged. If Δ> 0, the process proceeds to step 7, where the hydraulic control valve 36 is supplied to the upper chamber of the actuator 29,
Switch to drain oil from the lower chamber. If Δ = 0, the process proceeds to step 8 and the hydraulic pressure control valve 36 is switched so as to stop the oil supply and discharge to the upper chamber and the lower chamber of the actuator 29.

If Δ <0, the routine proceeds to step 9, where the hydraulic control valve 36 is switched so that oil is discharged from the upper chamber of the actuator 29 and oil is supplied to the lower chamber. As is apparent from the above description, in the above control, the vehicle body 11
The vertical velocity is calculated from the vertical acceleration of the shock absorber device 13, and the stroke velocity calculated from the stroke of the shock absorber device 13 is set so that a pseudo expansion / contraction stroke operation by the actuator 29 is added to the shock absorber device 13 in accordance with the vertical velocity. Based on this, the speed of the expansion / contraction stroke operation of the actuator is feedback-controlled.

By such control, the shock absorber device 13 is expanded and contracted as if the vertical movement of the vehicle body 11 is more than the original vertical movement of the vehicle body 11, and a large damping force is generated accordingly. Primary resonance vibration is suppressed, bouncing, pitching, and rolling of the vehicle body 11 are suppressed, and a flat ride comfort is obtained.

On the other hand, even if unsprung, that is, the vibration of the tire 12 occurs, it functions as a normal shock absorber device, so that the vibration of the tire 12 is suppressed as usual, and the vibration of the tire 12 side can be sufficiently suppressed. , The grip force of the tire 12 at the time of braking or turning can be secured, and the steering stability can be improved,
The safety can be improved. FIG. 6 shows the relationship between the conventional movement of the vehicle body, the shock absorber speed, and the generation of the damping force, and FIG. 5 is a characteristic diagram showing the same relationship of the present invention.

As is clear from the characteristic diagram, in the prior art, the speed of the vehicle body and the shock absorber speed are in a proportional relationship, but in the present invention, the shock absorber speed is increased with respect to the speed of the vehicle body and a large damping is achieved. Power is gained.

[0028]

As described above, according to the invention described in claim 1, the primary resonance vibration on the spring is suppressed, and the bouncing, pitching, and rolling on the spring are suppressed, and the ride comfort is flat. In addition, the unsprung side can be sufficiently damped, and, for example, the grip force of the tire (unsprung part) at the time of braking or turning can be secured, the steering stability can be improved, and the safety can be improved. .

[Brief description of drawings]

FIG. 1 is an overall system configuration diagram of an embodiment of the present invention

FIG. 2 is a sectional view of a shock absorber device according to the above embodiment.

FIG. 3 is a control block diagram of the above embodiment.

FIG. 4 is a flowchart illustrating the control content of the above embodiment.

FIG. 5 is a characteristic diagram of the present invention.

FIG. 6 is a characteristic diagram of a conventional technique.

FIG. 7 is a schematic view of a conventional suspension device.

FIG. 8 is a schematic diagram of a vibration system.

FIG. 9 is a schematic diagram of a vibration system.

[Figure 10] Schematic diagram of the vibration system

[Fig. 11] Schematic diagram of vibration system

[Figure 12] Characteristic diagram of conventional technology

[Explanation of symbols]

 11 Vehicle Body 12 Tire 13 Shock Absorber Device 29 Actuator 39 Stroke Sensor 40 Vertical Acceleration Sensor 41 Control Unit

Claims (1)

[Claims] 1. A shock absorber device is provided between a sprung part and an unsprung part of a vehicle, and the shock absorber device extends and contracts between the sprung or unsprung mounting end portion of the shock absorber device. An up-and-down speed detecting means for detecting an up-and-down speed on the spring through an actuator capable of performing a stroke operation, a telescopic stroke operating speed detecting means for detecting an elongating and contracting stroke operating speed of the actuator, the up-and-down speed detecting means and the Based on the detection signal output from the expansion / contraction stroke operation speed detection means, to control the expansion / contraction stroke operation speed of the actuator,
A vehicle suspension device comprising: a control unit that controls driving of the actuator.