JPH03104726A - Suspension for vehicle - Google Patents

Abstract

PURPOSE:To realize steering stability and comfortable ride by judging the direction of action of attenuation force based on the comparison of codes of speed on top of a spring and relative speed between the top of the spring and the bottom of the spring, judging the direction of stroke based on the code of relative speed at that time, and controlling either of the elongation side and the pressure side to high attenuation force and the other to low attenuation force in accordance with the result of judgement. CONSTITUTION:Speed on the top of a spring which is measured by a speed measuring means 2 on the top of the spring, relative speed between the top and the bottom of the spring which is measured by a relative speed measuring means 3, and the result of judgement of agreement or disagreement between codes of speed on the top of the spring and codes of relative speed in a code judging means 4 are input in a control signal output means 5. When codes of speed on the top of the spring agrees with codes of relative speed and relative speed is positive, it judges that attenuation force of a shock absorber acts in the direction of vibration regulation and is on the elongation side stroke and that the elongation side is a high attenuation force characteristic and the pressure side is a low attenuation force characteristic.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a vehicle suspension, and particularly to variable control of damping force.

(Prior Art) As a conventional vehicle suspension with variable damping force, for example, one described in Japanese Utility Model Application Laid-open No. 63-1'2914 is known.

This conventional suspension detects the relative displacement between the sprung mass and the unsprung mass, and if the displacement is a change in the direction away from the neutral position, the damping force is set to a low damping force characteristic (hereinafter referred to as soft), and the If the change is in the direction of returning to the position, it is considered a high damping force characteristic (hereinafter referred to as hard), and the relative displacement state between the upper and lower parts of the spring changes from hard to soft in a shorter time than the switching time of the shock absorber. When the situation requires switching, the system is configured to force a soft state.

(Problem to be Solved by the Invention) However, in the above-mentioned conventional East Ryoyo The Suspension, when the suspension is made hard, both the extension side and the compression side are made hard, and when it is made soft, the suspension is made hard. Since both the extension side and the compression side were made soft, there were the following problems.

When the damping force is set to hard during low-frequency vibrations, at the same time, if manual force is applied to medium- and high-frequency vibration components due to small irregularities on the road surface, etc., the damping force is set to hard with priority given to the low-frequency vibrations. In such cases, both the extension side component and the compression side component of the high frequency vibration components are affected by the human force of the heavy body, worsening the ride comfort.

Furthermore, if the response to medium and high frequency components is prioritized and the response is forcibly made soft, the vibration input to the vehicle body is suppressed, but the steering stability deteriorates.

In other words, it was not possible to achieve both handling stability and ride comfort.

In addition, during bouncing, the damping force of the shock absorber is repeatedly switched between acting in the excitation direction and acting in the damping direction, and each time, the damping force characteristics can be switched between hard and soft. Therefore, the number of times of switching is large, and there is a problem in terms of durability of the damping force variable means.

The present invention has been made by focusing on the conventional problems as described in -L, and aims to achieve both steering stability and easterly comfort in a state where low frequency vibration and medium/high frequency vibration are simultaneously applied manually. Another object of the present invention is to provide a vehicle suspension that can improve the durability of the damping force variable means by reducing the number of times the damping range is switched.

(Means for Solving the Problems) In order to achieve the above-mentioned objects, in the dual-use suspension of the present invention, as shown in the first leap which is a block diagram showing the basic configuration of the present invention, the control signal is The driving means 1a is driven by an input, and includes a shock absorber l that can change the rebound damping force and pressure damping force to at least a low damping force characteristic and a high damping force characteristic, respectively, and a spring [spring mass for measuring speed]. A speed measurement stage 2, a relative speed measurement f stage 3 that measures the relative speed between the sprung mass and the unsprung mass, and a code publication fixed stage 3 that determines whether the sign of the sprung mass speed and the sign of the relative speed match or do not match. 4, both signs match, and the sign of relative velocity is positive, with high damping force on the rebound side. Pressure (III+) is determined to be a low damping force, and when both signs match and the sign of relative velocity is negative, the rebound side should be a low damping force and the compression side should be a high damping force. On the other hand, when the signs do not match and the sign of the relative velocity is positive, it is determined that the rebound side should have a low damping force and the compression side should have a high damping force. When they do not match and the sign of the relative velocity is negative, it is determined that the rebound side should have a high damping force and the compression side should have a low damping force, and further, L 1:
11 outputs a control signal based on the fixed conduit, and is provided with a control signal output stage 5 in which a predetermined length interval is set from outputting this control signal to outputting the next control signal. .

(for production) The operation of the vehicle suspension of the present invention will be explained.

The control signal output means includes the spring speed measured by the spring L speed measuring means, the relative speed between the sprung mass and the spring foot measured by the relative speed measuring means, and the T11 constant means. , Spring-E The sign of the velocity and the sign of the relative velocity match. 111 results with discrepancies are manually generated.

When the signs of the sprung mass speed and the relative speed match and the relative speed is positive, the damping force of the shock absorber is acting in the damping direction and the t11 cutoff is determined to be in the extension stroke. The rebound side has high damping force characteristics. 1-11 that the compression side should have low damping force characteristics.

Further, the signs of the sprung mass velocity and the relative velocity match, and
When the relative speed is negative, it is determined that the damping force of the shock absorber is acting in the damping direction and the stroke is overwhelming, and the rebound side is set to low damping force characteristics. It is determined that the compression side should have high damping force characteristics. In this way, when the signs of the sprung mass speed and the relative speed match, the damping force of the shock absorber acts in the damping direction, and in this case, by making the damping force in the stroke direction a high damping force characteristic, , increasing the III vibration energy relative to the vibration energy transmitted to the vehicle body,
In addition to improving handling stability, the damping force in the opposite direction to the stroke has a low damping force characteristic, which absorbs the input of medium and high frequency components on the reverse stroke side that is transmitted to the vehicle body, improving ride comfort. It is possible to improve the On the other hand, the signs of the sprung mass velocity and the relative velocity do not match,
When the relative velocity is positive, it is determined that the damping force of the shock absorber is acting in the excitation direction and that the stroke is on the extension side, and the extension side has low damping force characteristics. It is determined that overwhelming should be made into a high/low damping force characteristic.

Also, the signs of the sprung mass speed and relative speed do not match,
In addition, when the relative speed is negative, the damping force of the shock absorber is acting in the excitation direction, and it is determined that the compression side stroke is occurring, and the rebound side has high damping force characteristics. It is determined that the compression side should have low damping force characteristics.

In this way, when the signs of the sprung mass speed and the relative speed do not match, the damping force of the shock absorber acts in the excitation direction, and in this case, the damping force in the stroke direction is treated as a low damping force characteristic, and the damping force is It absorbs the transmitted vibration energy and improves riding comfort. At this time, the side opposite to the stroke direction has a high damping force characteristic.

The III # signal output means that makes such a determination outputs a control signal to the shock absorber driving means based on the determination result, and outputs one control signal and outputs the next control signal. An interval of a predetermined length is set until the above-mentioned determination result is output, and no control signal is output during this interval, no matter how many of the above-mentioned judgment results are obtained.

In addition, in this invention, the high and low damping force characteristics are different between the rebound side and the overwhelm, so if you fall over, the shock absorber will repeat expansion and contraction like when bouncing, and the damping force of the shock absorber will decrease. If the vibration damping direction and the excitation direction are repeated, one of the expansion side and compression side should be set to a high damping force characteristic to damp the vibration, and then the other side should be set to a low damping force characteristic so as not to act in the excitation direction. This control is repeated.

In this case, when damping, the stroke side has a high damping force characteristic, and when excitation, the side opposite to the stroke direction has a low damping force characteristic.In the present invention, both are in the same control mode, and there is no difference between the two. There is no need to switch characteristics.

Therefore, when the damping force repeatedly changes between the state in which it acts in the damping direction and the state in which it acts in the vibration excitation direction, such as during bowing, the number of times of switching can be reduced.

(Example) Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

First, the configuration of the embodiment will be explained.

FIG. 2 is a schematic diagram showing the structure of the suspension according to the embodiment of the present invention. This suspension A includes a strut IO interposed between a vehicle body B and each wheel W, a load sensor it and an acceleration sensor l2 provided at the base end of this strut IO, and both sensors 11 and 12.
Human power signal from d. It consists of a controller l3 that outputs a control signal S based on a.

In addition, in this FIG. 2, there is one vehicle W, and correspondingly one set of struts 10 and both sensors 11. 12, this l set of struts lO and both sensors 11
．． 12 is provided for each wheel W.

Further, I4 in FIG. 2 is a mount insulator.

The strut IO has a variable damping force type shock absorber 20 and a spring 30, and the structure of the shock absorber 20 will be briefly explained based on the main part sectional view of FIG. 3.

In the figure, 2I indicates a cylindrical cylinder.

The cylinder 21 is filled with a fluid such as oil, and is defined into a living chamber 23 and a lower chamber 24 by a slidably mounted piston 22 .

The piston 22 is attached to the tip of a piston rod 25, and the piston 22 is provided with disks 22a on the -1 and 1 side, and an expansion disk valve 22l on the lower surface.

That is, during the compression side stroke, from the compression side communication hole 22h, the inner and outer grooves 22j. 22k, this pressure side disc valve 22
The fluid that opens valve a is allowed to flow, and a damping force is generated. Also, during the extension stroke, the inner and outer grooves 22rx are similarly formed from the extension communication hole 22m. At 22p, fluid flows to open the expansion side disc valve 22b, and a damping force is generated.

In addition, 22C is Ridena, 22d. 22e is Watsusha, 2
2f is a spring seat, and 22g is a spring.

In addition, the piston 22 and the piston rod 25' are formed with a pressure side passage 22q that communicates the groove 22j and the groove 22k (see Fig. 4), and also has a pressure side passage 22q that communicates the groove 22j and the groove 22k.
A growth-side flow path 22r is formed that communicates with the flow path 22r, and an adjustment channel 26 is provided in the middle thereof.

The adjuster 26 is provided rotatably in the circumferential direction, and is formed in a cylindrical shape with a bottom with a hollow portion 26a as shown in the figure. A communication hole 26b is formed, and an expansion side communication hole 26e is formed to correspond to the expansion side flow path 22r.

Both orifice holes 26b and 26e are shown in FIG.
As shown in FIG. 6, which is a cross-section of FIG.

In other words, as shown in the figure, the pressure side communication hole 26 is provided in the pressure side flow path 22q.
In a state in which the compression side passages 22q are connected by matching b, the compression side has a low damping force (hereinafter referred to as soft).
is oriented in the right angle direction, the adjuster 26 blocks the expansion side flow path 22r, and a high damping force (hereinafter referred to as hard) is achieved on the expansion side.

On the other hand, when the growth side communication hole 26c is aligned with the growth side flow path 22r and the growth side is made soft l., the adjuster 26 blocks the compression side flow fi22q and the overwhelm becomes hard.

The adjustment rod 26 is rotated by a control rod 27 provided in the through hole 25a of the piston rod 25. The control rod 27 extends to the upper end of the piston rod 25, and A rotational force is applied by a motor actuator 28 provided at the vehicle body mounting portion of 25 (see Fig. 2, pl<).

The load sensor 1l is fastened together with the mounting part of the piston rod 25 on the vehicle body B, and has a structure with distortion resistance, and outputs an electric signal d corresponding to the load input to the mounting part of the piston rod 25. It has become.

That is, this insect sensor 114;j, is provided as a relative speed measuring means for measuring the relative speed between the upper and lower parts of the spring, and uses the predetermined charge obtained when the shock absorber 20 is in the neutral position as a reference value. The relative speed can be determined depending on whether the detected load is higher or lower than this reference value.In other words, in the case of this embodiment, in the extension stroke where the relative speed is positive, the detected charge is greater than or equal to the reference value, and on the other hand, The mount structure is such that the detected load is less than the standard value in the compression stroke where the relative speed is negative. The acceleration sensor l2 is connected to the motor actuator 2.
8 and outputs an electrical signal a corresponding to the vertical acceleration acting on the upper end of the sprung piston rod 25. That is, the acceleration detected by this acceleration sensor 12 is a differential value of the sprung mass speed, and the acceleration detected by this acceleration sensor 12 is a differential value of the sprung mass speed.
is provided as a sprung speed measuring means 7. still,
In this acceleration sensor l2, the upward acceleration is a "positive" value, and the downward acceleration is a "negative JO" {f
It is obtained as i.

The controller 14 corresponds to the constant means and the control signal output means in the claims, and the controller 14 corresponds to the constant means and control signal output means in the claims.
1 and an input signal from acceleration sensor l2 d. Based on a, in order to give the shock absorber 20 an optimal damping force,
It outputs a control signal S to the actuator 28, and FIG. 7 shows its structure.

That is, the controller 13 includes an interface circuit l3a that inputs signals d and a from both sensors 11 and 12, an A/D conversion circuit 13b that converts the input analog signals into digital signals, and an input signal and a memory circuit 13c that input signals stored in the interface circuit l3a. CPU 1 performs calculations and judgments to be described later based on numerical values.
3d, a drive circuit 13e that outputs a control signal S to the actuator 28 based on the calculation/judgment result of the CPU 13d;
．． 13f.

Next, the operation of this controller 13 will be explained based on the flowchart shown in FIG.

First, in step 101, the signs of the detected load D and the detected acceleration A are set to "positive", and the timer flag is set to rO.
Make initial settings for J. Next, in steps 102 and 103, the A/D conversion circuit 13b performs A/D conversion of the input signal d indicating the load D and the input signal a indicating the acceleration A. Next, in step 104, it is determined whether the acceleration A on the spring is at a maximum. That is, in this judgment step 104 and the next judgment step 105, the state of the sprung mass speed is determined based on the acceleration A on the spring, and from the time when the acceleration A becomes the maximum until the time when the acceleration A becomes the next minimum, It is determined that the sprung mass velocity is "positive", and processing is performed to set the sign of acceleration A to "positive" in processing step 106. On the other hand, during the period from when acceleration A becomes minimum until it becomes maximum next time, ,
It is determined that the sprung mass speed is “negative” and processing step 1 is performed.
In step 07, the sign of acceleration A is set to "negative". Next, in step 108, it is determined whether the load D is greater than or equal to a reference value. That is, as mentioned above, this load D is manually applied to measure the relative speed;
is greater than or equal to the reference value, it means that an extension stroke in which the relative velocity is positive is being completed, and in step 109 the sign of the load D is set to "positive j".

On the other hand, if this load D is less than the reference value, it means that an overwhelming stroke in which the relative velocity is negative is being performed, and the sign of the load is set to "negative" in step 110. Next, in step Ill, as a pre-step for determining whether the signs of the acceleration A and the load D match, a calculation is performed to multiply the acceleration A and the load D. That is, if the signs match, the multiplied value C will be r positive, and if they do not match, the value C will be negative. Then, in the subsequent determination step 112, it is determined whether or not this calculated value C is positive. If it is "positive" (YES), the process proceeds to the next determination step l13, and the load is "
``Correct'' is determined, and then ``Correct J (YE
S), the process proceeds to step 114, where "negative J (N
O), the process advances to step 115.

On the other hand, in step 112, the calculated value C is "negative" (NO
), the process proceeds to step l16, where it is determined whether the load D is "positive" in the same way as step 113. If YES, the process proceeds to step 115; if NO, the process proceeds to step 114. Proceed to. Then, in step 114, the timer flag is set to "0".
”, and if it is “0”, the process proceeds to step 117 and outputs a control signal S to the actuator 28 to set the damping force characteristics of the shock absorber 20 to be soft on the rebound side and hard on the compression side. 6, that is, rotate the adjuster 26 to the state shown in FIG. If the timer flag is "1" (NO), the process proceeds to step 118, where the adjuster 26 is held as it is, and then the process proceeds to step 121.

On the other hand, it is also determined in step 115 whether the timer flag is "O", and if YES, the process proceeds to step 119, in which the actuator 28 A process of outputting the control signal S is performed at step 118, and if the result is N, the process proceeds to step 118.

Then, after performing steps 117 and 119,
Proceeding to step 120, the timer flag is set to "IJ", a process for activating the timer function included in the CPU 1.3d is performed, and the process proceeds to step 121.

In this step 121, it is determined whether the timer flag is "0" or "1.1" to determine whether the timer has timed up. If YES, the process proceeds to step 122, where the timer flag is set to rOJ, and step 102 On the other hand, if the answer is NO, the process proceeds to step 123, where the timer continues counting, and the process returns to step 102.

Next, the operation of the embodiment in each driving situation of the vehicle will be explained.

(a) During roll When turning, the vehicle body B rolls, the right side of the vehicle body displaces upward, and the left side of the vehicle body displaces downward, and then converges to the neutral position while vibrating.

FIG. 9 is a time chart showing the displacement of the sprung mass on the left and right sides of the vehicle body, the sign states of the acceleration A and load D detected on the left and right sides of the vehicle body, and the damping force characteristics of the shock absorbers 20 on the left and right sides of the vehicle body during a right turn. The ■RH displacement and ■Li{displacement in Fig. 9 indicate the displacement states of the right and left sides of the vehicle body, respectively.The solid line indicates the sprung mass displacement, and the dotted line indicates the sprung mass speed. There is. In this case, the road surface is assumed to be flat. In addition, the ORH acceleration A and load D below are calculated by the acceleration sensor l on the right side of the vehicle body corresponding to the displacement shown in ■ and ■.
8 shows the signs of acceleration A and load D given by processing steps 106, 107, 109, and 110 in FIG.

Also, ■LH acceleration A and load D indicate the sign state of similar acceleration A and load D on the left side of the vehicle body.
Note that the first range of @ and ■ indicates the sign corresponding to the initial setting in step 101.

Furthermore, @damping force below indicates the damping force characteristic of the shock absorber 20 determined as a result of the calculation and determination of the controller 13 shown in flowchart 1 in FIG.
}{ indicates the damping force characteristic (H: hard. S: soft) of the shock absorber 20 on the right side of the vehicle body, and LH indicates the damping force characteristic of the shock absorber 20 on the left side of the vehicle body.6 Therefore, such a At the time of rotation, the shock absorber 20 always has its damping force acting in the damping direction (the signs match), and the extension stroke and the compression stroke are alternately repeated.

Therefore, the shock absorber 20 can always keep the stroke direction hard and L7 to suppress roll and obtain steering stability. In addition, in response to this, the reverse stroke side is softly controlled to absorb vibrations in the reverse stroke direction and improve ride comfort when there is medium to high frequency input from the road surface at the same time as this allocation. 6 0]) Dive and Scut When braking or accelerating, a dive or scut occurs.

In this case, as in the case of roll, control is performed to suppress such attitude changes.

Therefore, the operation in this case is the same as the control performed on the left and right sides during a roll, but the same operation is performed for the front and back.In other words, the rebound side is made hard and the compression side is made soft, and the vibrations are damped on the rebound side stroke. This method alternately controls the vibration-suppressing state and a state in which the extension side is soft and the overwhelm is hard, damping the compression side stroke, thereby suppressing scuts and dives.

fc) During bouncing FIG. 10 shows a time chart when driving on a rough road.

When driving on such rough roads, each shock absorber 20 strokes according to the unevenness of the road surface on which each wheel travels.In the same figure @Spring mass displacement, the solid line indicates the sprung mass displacement, and the dotted line indicates the displacement speed. It shows.

And, below that, ■Road surface displacement indicates the condition of the road surface R and the vehicle transport W.

Furthermore, under @relative displacement, the solid line represents the relative displacement,
The dotted line indicates relative velocity.

In such a case, the sign of the acceleration A (corresponding to the sign of the sprung mass speed) and the load D (corresponding to the sign of the relative speed) given by calculation and determination in the controller l3
The symbols are as shown in the same figure @. As a result, the damping force characteristic of the shock absorber 20 controlled by the controller l3 becomes as shown in (2) damping force.

Note that the symbol (■) in the figure shows the stroke direction of the shock absorber 20.

That is, in this time chart, in the range (1), based on the initial setting in step 101, the expansion side or the hard side.
The pressure side is soft. In the range of (2), the overwhelming stroke is completed and the damping force acts in the excitation direction, so control is performed to make the extension side hard and the overwhelming side soft. maintain the state of

Next, in range (3), the stroke direction switches to the extension side and the damping force changes to a state where it acts in the damping direction, so the extension side is made hard and the compression side is made soft. 2)
maintain the state of

Next, in the range (4), the expansion side stroke is in progress and the damping force changes to act in the excitation direction, so the adjuster 26 is rotated to make the expansion side soft and the compression side hard. to switch characteristics.

Next, in the range (5), the stroke direction switches to the compression side and the damping force changes to a state where it acts in the damping direction, so the rebound side becomes soft. The pressure side is hard, (4)
Maintain the state of . Next, in the range (6), the overwhelming stroke is in progress and the damping force changes to act in the excitation direction, so the extension side is hard. In order to soften the overpowering effect, the characteristics are changed by rotating the adjuster 26.

Next, in the range (7), the stroke direction switches to the expansion side and the damping force changes to a state where it acts in the damping direction, so the expansion side is hard and the overpowering is soft. 6)
Maintain the state of . As described above, the damping force of the shock absorber 20 is controlled in a direction that minimizes the rate of change of energy on the spring according to the input from the road surface R and the movement of the spring, thereby damping bouncing.

Furthermore, during this bousing, the damping force mode of the shock absorber 20 changes in seven ways depending on when the damping force of the shock absorber 20 acts in the damping direction and when it acts in the excitation direction, but on the rebound side. Since the control is performed so that one side of the pressure is hard and the other is soft, the actual switching operation is only performed twice at point Cl and point C2 in Figure 10.
It is not necessary to switch the characteristics every time the mode changes, the number of switchings can be reduced, and the durability of the actuator 28, adjuster 26, etc. can be improved.

By the way, the above explanation of the operation is for the operation to obtain the optimum damping force characteristic, and in this embodiment, the control signal is not necessarily output so as to obtain such a characteristic. ．． This can be seen from the fact that steps 114 and 115 for determining the time flag are provided before steps 117 and 119 for performing processing for changing the damping force in the flowchart of FIG.
This is because when switching the damping force, not only the acceleration and the load but also the interval (timer time) from outputting the control signal S to outputting the next control signal S is included as a condition. Note that this timer time is set to be longer than the operation response time of the actuator 28. That is, in Fig. 10, ■ indicates the output state of the control signal S, and like the others, the horizontal axis indicates time. The length of one section on the horizontal axis is the interval Int from outputting the control signal S to outputting the next control signal S.
It shows the length.

As shown in (■), in this embodiment, the first control signal S
After outputting, every time the interval Int elapses,
At that time, a control signal S is output in order to form a damping force characteristic according to the calculation result of the ideal damping force shown in (2).

Therefore, in this embodiment, since there is no possibility that control No. 1 is output faster than the response of the actuator 28,
The embodiments of the present invention have been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and even if the design of the blade is changed within the scope of the gist of the present invention, it is included in the present invention. For example, in the embodiment, an example was shown in which the characteristics were changed by rotating the adjuster, but there are other means to change the damping force, such as a structure in which a subur that changes the aperture opening is slid up and down. It is not limited to this.

Further, the valve structure 6 for generating the damping force may be arbitrarily determined according to the required characteristics, and is not limited to 4° in this embodiment.

In addition, in the embodiment, as a means for measuring the sprung speed,
Although a means for measuring acceleration is provided, other means may be used as long as it is capable of measuring sprung mass speed.

Further, in the embodiment, a load sensor is used as a means for measuring the relative speed, but other means may be used, such as means for measuring relative displacement between the sprung part and the unsprung part.

(Effects of the Invention) As explained above, in the vehicle suspension of the present invention, the direction of action of the damping force is determined based on the sign comparison between the sprung speed and the relative speed between the i-h-unsprung portion. At the same time, the direction of travel is determined based on the sign of the relative velocity at that time, and based on the result of this determination, one of the rebound and compression sides is controlled to have a high damping force and the other to a low damping force.
When allocating high damping force in the stroke direction, low damping force occurs in the reverse stroke direction, which prevents input transmission in the opposite direction to the stroke direction among medium and high frequency components input at the same time, improving steering stability. The effect is that it is possible to achieve both comfort and riding comfort. Furthermore, in the present invention, by having the above-mentioned configuration,
Particularly in the case of bouncing allocation during bouncing, the number of changes in the damping force characteristics can be reduced compared to the conventional method, and the durability of the means for changing the damping force can be improved.

In addition, in the present invention, a predetermined length interval is provided when outputting a control signal, and the control signal is not output during that time, which also reduces the number of changes to the damping force characteristics and improves durability. You can do it. In other words, even if the sampled data from the sensor frequently produces a '#t1 constant result due to disturbances, noise, etc., the damping force characteristics will not change frequently and durability can be improved. be.

In addition, it is possible to prevent problems such as switching the driving means such that the driving means drives in the opposite direction while being driven in one direction, and problems caused by inputting a control signal that exceeds the responsiveness of the driving means.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing the basic configuration of the present invention, Fig. 2 is an overall view showing a suspension A according to an embodiment of the invention, Fig. 3 is a sectional view showing the main parts of a shock absorber of the suspension according to the embodiment, and Fig. FIG. 4 is a sectional view showing the upper end surface of the piston, which is the main part of the embodiment, FIG. 5 is a sectional view taken along the line V-V in FIG. 3, and FIG. FIG. 7 is a block diagram showing the controller of the embodiment suspension;
Fig. 8 is a flowchart showing the operation flow of the controller of the embodiment, Fig. 9 is a time chart showing the operation of the embodiment suspension when turning to the right, and Fig. 10 is a time chart showing the operation of the embodiment suspension when bouncing. It is. l...Shock absorber 2...Spring mass speed measurement 1,000 steps 3...Relative speed measurement 1,000 steps 4...Symbol II constant means 5...Control signal output means

Claims (1)

[Scope of Claims] 1) A shock absorber whose driving means can be driven by input of a control signal to change the rebound damping force and the compression damping force into at least a low damping force characteristic and a high damping force characteristic, respectively; A sprung mass speed measuring means for measuring sprung mass speed;
a relative speed measuring means for measuring the relative speed between unsprung parts; a sign determining means for determining whether the sign of the sprung speed and the sign of the relative speed match; When is positive,
It is determined that the rebound side should have a high damping force and the compression side should have a low damping force, and when both signs match and the sign of the relative velocity is negative, the rebound side should have a low damping force and the compression side should have a high damping force. On the other hand, when the signs do not match and the sign of the relative velocity is positive, it is determined that the rebound side should be a low damping force and the compression side a high damping force. When the signs do not match and the sign of the relative speed is negative, it is determined that the rebound side should have a high damping force and the compression side should have a low damping force, and a control signal is output based on the above judgment result. 1. A vehicle suspension comprising: a control signal output means in which a predetermined interval is set between outputting this control signal and outputting the next control signal;