JPH0618008U - Suspension damping force control device - Google Patents

Abstract

(57) [Summary] [Object] The present invention aims to provide a suspension damping force control device that improves the riding comfort by changing the suspension damping force in two steps in real time according to the road surface condition. . A sign of a product of an acceleration sensor for vertical acceleration on a spring, a stroke sensor for detecting relative displacement between the sprung and unsprung, and an integrated value of a signal from the acceleration sensor and a signal from the stroke sensor. And a control device for switching the switching valve.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a suspension damping force control device having a shock absorber and provided with a switching valve for switching the flow of oil in the shock absorber between two stages.

[0002]

[Prior art]

 The damping force of the shock absorber provided between the vehicle body and each wheel is switched between two levels depending on the sign of both the upper and lower speeds on the spring and the relative speed between the sprung and unsprung parts to improve the riding center. The technique is known, for example, in USP 3807678.

[0003]

[Problems to be solved by the device]

 However, in the above technology, since the damping force of the shock absorber is switched in real time by the code of the speed signal, if the response delay of switching the damping force becomes large (for example, 20 msec or more), the desired damping force cannot be obtained, and the riding force is changed. The problem of being uncomfortable occurs.

[0004] Also, Japanese Utility Model Application Laid-Open No. 3-118107 disclosed by the applicant of the present application is a technique relating to an active suspension.

[0005] Also, although there is Japanese Utility Model Laid-Open No. 3-78025 by the present applicant, it is a technique for increasing the damping force at the time of braking to reduce the nose dive, and neither is related to the above problem.

Therefore, an object of the present invention is to provide a suspension damping force control device that changes the suspension damping force in two steps in real time according to the road surface condition to improve the riding comfort.

[0007]

According to the present invention, a damping force control device for a suspension is provided in a suspension damping force control device having a shock absorber and provided with a switching valve for switching the flow of oil in the shock absorber between two stages. A sign of the product of an acceleration sensor that detects the upward and downward acceleration, a stroke sensor that detects the relative displacement between the sprung part and the unsprung part, and the integrated value of the signal from the acceleration sensor and the signal from the stroke sensor. When is positive, the switching valve is switched to the soft side, and when negative, it is switched to the hardware side.

[0008]

[Action]

 In the suspension damping force control device configured as described above, the stroke, which is the relative displacement between the sprung and unsprung, was directly input to the control device, so it is correct to input the relative speed, but the vertical direction is correct. In normal vehicle vibration with a road surface input with a repetitive waveform, the phase difference between the relative speed change and the relative displacement change becomes a value that compensates for the delay in the response of damping force switching, so obtain an appropriate damping force. You can

[0009]

【Example】

 Hereinafter, embodiments of the present invention will be described with reference to the drawings.

In FIG. 1, between the vehicle body side B and the wheel side C, for example, in the case of the left front wheel, a shock absorber 1a and a stroke sensor 3a for detecting the stroke of the shock absorber 1a are provided. Is provided with an acceleration sensor 4a for detecting vertical acceleration on the spring.

Further, the shock absorber 1a is provided with a switching valve 2a for switching the damping force by switching the oil flow rate between a hard damping force and a soft damping force.

The switching valve 2a, the acceleration sensor 4a, and the stroke sensor 3a are connected to the control device 5 by an electric circuit.

Each of the other wheels is similarly configured.

FIG. 2 shows a block diagram of the control device 5. The output of each stroke sensor 3 is input to the stroke signal input means 6 and attenuated via the damping force switching determination means 7 and the drive signal output means 10. It is connected to a switching valve 2 that switches the force between two stages.

Further, the acceleration sensor 4 is connected to the damping force switching determination means 7 via an acceleration signal input means 8 and an acceleration signal integration means 9.

The operation will be described below with reference to FIG.

At the time of operation, the stroke signal ZR is read (step S1). Then, the acceleration of the sprung acceleration signal ZA is read (step S2). Then, the acceleration value of ZA is integrated (step S3).

Here, the stroke ZR and the velocity ZA obtained by integrating the acceleration ZA have positive and negative signs, respectively.

The product of the velocity of ZA and ZR is obtained, and its positive or negative is judged (step S4).

Referring also to the control map shown in FIG. 4, a switching signal for switching the damping force to the hard side is output when the value is negative (step S5), and a switching signal for switching the damping force to the software side when the value is positive. Is output (step S6). The above steps S1 to S6 are periodically repeated.

[0021]

[Effect of device]

 Since the present invention is configured as described above, as shown in FIG. 5, when there is a repetitive waveform road surface input, even if the response delay d of the shock absorber is large, the stroke is input and the phase difference is input. Since the response delay of the damping force switching is compensated by this, desired damping force switching close to the ideal state can be performed, and the riding comfort is improved compared to the conventional techniques shown in FIGS. 6 and 7.

[Brief description of drawings]

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

FIG. 2 is a block diagram of the control device shown in FIG.

FIG. 3 is a flowchart of the control of FIG.

FIG. 4 is a control map diagram of FIG. 1.

5 is a diagram showing an example of the operation of FIG.

FIG. 6 is a diagram showing an example of a conventional control map.

FIG. 7 is a diagram showing an example of operation of a conventional technique.

[Explanation of symbols]

 1 ... Shock absorber 2 ... Switching valve 3 ... Stroke sensor 4 ... Acceleration sensor 5 ... Control device

Claims (1)

[Scope of utility model registration request] 1. A suspension damping force control device having a shock absorber, wherein a switching valve for switching the flow of oil in the shock absorber between two stages is provided, and an acceleration sensor and a spring for detecting vertical acceleration on the spring. When the sign of the product of the stroke sensor that detects the relative displacement between the upper and unsprung parts, and the integrated value of the signal from the acceleration sensor and the signal from the stroke sensor is positive, the switching valve is switched to the soft side. A damping force control device for a suspension characterized in that a control device for switching to a hard side when a negative value is provided.