JPH05169958A - Damping force variable shock absorber and control device thereof - Google Patents

Abstract

PURPOSE:To provide a damping force variable shock absorber which can independently control both extension side damping force and contraction side damping force by a valve means having one movable part, and a damping force variable shock absorber control device which controls the extension side damping force and the contraction side damping force according to various running conditions. CONSTITUTION:The lower end part of a piston rod 103 is formed into a cylinder, a control valve 10, a contraction side exclusive flow passage 11, and an extension side exclusive flow passage 12 are provided in the cylinder, and the contraction side exclusive flow passage 11 and the extension side exclusive flow passage 12 are respectively opened/closed with plate-like check valves 109, 110 provided on the piston rod 103 and communicated to an upper liquid chamber 1a. The control valve 10 is provided with a contraction side exclusive hole 15 and an extension side exclusive hole 16, and a sub-flow passage H in the control valve 10 and the contraction side exclusive flow passage 11 or the extension side exclusive flow passage 12 is communicated or intercepted by rotation of the control valve 10, as shown in the figure (b), (c).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shock absorber capable of switching damping force settings for a vehicle and a control device therefor.

[0002]

2. Description of the Related Art Conventionally, in order to improve the riding comfort and steering stability of a vehicle, skyhook dampers have been devised which generate a damping force proportional to the absolute speed on the spring. This skyhook damper is an ideal damper that suspends a damper from a fixed point in space and suppresses vibration of the vehicle body by this damper so as to prevent road irregularities from being transmitted to the vehicle body.

By the way, Karnopp has proposed a control method for realizing a characteristic close to that of a skyhook damper by a semi-active suspension. Kar
In the nopp method, as shown in FIGS. 29 and 30, the absolute velocity dX2 on the spring and the relative velocity dX2 between the unsprung and unsprung portions.
When the sign of −dX1 is the same, that is, when the vehicle body and the wheels move in opposite directions, and when the vehicle body and the wheels move in the same direction and the vehicle body moving speed is faster than the wheel moving speed (the damping force is When damping the vehicle body), increase the damping force of the shock absorber. Further, when the positive and negative of the two speeds are different, that is, when the vehicle body and the wheel move in the same direction and the moving speed of the wheel is faster than the moving speed of the vehicle body (when the damping force excites the vehicle body). Controls to reduce the damping force.

In one conventional device, a sprung acceleration sensor and a stroke sensor are attached to a vehicle, the absolute signal on the spring is detected by integrating the output signal of the sprung acceleration sensor, and the output signal of the stroke sensor is differentiated. By doing so, the relative speed between the sprung and unsprung parts was detected. Then, the damping force is changed when the positive / negative of the sprung absolute speed changes and when the positive / negative of the relative speed between the sprung unsprung parts changes.

However, in the above apparatus, the damping force is changed, that is, the flow passage area is changed by the valve means in accordance with the positive and negative changes in the sprung absolute velocity and the sprung unsprung relative velocity. The relative speed between the sprung part and the unsprung part here is affected by unsprung vibration, and its frequency is several Hz.
Up to several tens of Hz, and since the flow path area must be changed to follow this, the frequency of operation increases and durability becomes a problem. In addition, high speed response is required for the change.

Therefore, the following apparatus has been proposed as a method for solving the above problems. For example, JP-A-61
In the device disclosed in FIG. 12 of Japanese Patent No. 236938,
The shock absorber has an expansion-side dedicated flow path and a contraction-side dedicated flow path, and has a configuration in which the expansion-side damping force and the contraction-side damping force can be changed by one valve means. According to the above device, it is possible to obtain a characteristic close to that of the skyhook damper without changing the damping force according to the change in the relative speed between the sprung portion and the unsprung portion, but both the extension side damping force and the contraction side damping force can be obtained. There is a problem that both the minimum value and the maximum value cannot be controlled independently. That is, it is not possible to increase both the extension side damping force and the contraction side damping force in order to improve stability during high speed running. Alternatively, the vibration of the vehicle body is very small and stable, and it is impossible to reduce both the expansion-side damping force and the contraction-side damping force in advance in order to cope with a sudden input such as a protrusion.

Further, the apparatus disclosed in FIG. 10 of Japanese Patent Application Laid-Open No. 61-236938 and the apparatus disclosed in Japanese Patent Application Laid-Open No. 61-282108 are provided with two independently movable valve means, and extend. The side damping force and the contraction side damping force can be controlled completely independently, but since there are two valve means, there is a problem that the device configuration becomes complicated and large. That is, since the shock absorber is originally arranged in the limited space between the tire and the vehicle body, considering the arrangement situation, it has been an inevitable requirement from the past that the device be simple and compact. Therefore, although the device of the above publication can independently control the extension side damping force and the contraction side damping force, it cannot be said that the conventional problems have been solved, and further improvement is desired.

[0008]

Therefore, the present invention has been made in view of the above problems, and is close to a skyhook damper without changing the damping force according to the change in the relative speed between the sprung and unsprung portions. While achieving the initial purpose of realizing the characteristics, it has an expansion side dedicated flow path and a contraction side dedicated flow path, and both the expansion side damping force and the compression side damping force can be controlled independently without using multiple valve means. It is a first object to provide a variable damping force shock absorber.

A second object of the present invention is to provide a damping force variable shock absorber control device for controlling the extension side damping force and the contraction side damping force according to various running conditions by using the above damping force variable shock absorber. And

[0010]

In order to solve the above-mentioned problems, a first damping force variable shock absorber of the present invention is provided with a cylinder in which a working fluid is stored, and a slidable inside the cylinder. A piston member that divides the inside of the chamber into an upper chamber and a lower chamber, a first communication passage that allows the working fluid to flow from the upper chamber to the lower chamber, and a working fluid from the lower chamber to the upper chamber. A second communication passage that allows circulation, a first hole that adjusts the flow passage area of the first communication passage, and a second hole that adjusts the flow passage area of the second communication passage are arranged. Position, second position, and valve means for stopping at the third position, and when the valve means stops at the first position, the first hole reduces the flow passage area of the first communication passage. , The second hole is at a position where the flow passage area of the second communication passage is small, and the valve means is at the second position. The first hole when stopping the first
When the valve means is stopped at a position where the flow passage area of the communication passage is small, the second hole is at a position where the flow passage area of the second communication passage is large, and the valve means is stopped at the third position, the first hole is The first hole and the second hole are arranged such that the flow passage area of the first communication passage is large and the second hole is at a position where the flow passage area of the second communication passage is small. Is characterized by.

A second damping force variable shock absorber of the present invention is a cylinder in which a working fluid is stored, and a piston member slidably provided in the cylinder and dividing the inside of the cylinder into an upper chamber and a lower chamber. A first communication passage that allows the working fluid to flow from the upper chamber to the lower chamber; a second communication passage that allows the working fluid to flow from the lower chamber to the upper chamber; A first hole for adjusting the flow passage area of the second communication passage, and a second hole for adjusting the flow passage area of the second communication passage
And a valve means for stopping at the first position, the second position, and the third position, the first hole being at the first position when the valve means is stopped at the first position. When the flow passage area of the communication passage is large, the second hole is at a position where the flow passage area of the second communication passage is large, and when the valve means is stopped at the second position, the first passage is formed.
Of the first communication passage has a small flow passage area, and the second hole has a large flow passage area of the second communication passage.
When stopped at the position, the first hole has a large flow passage area of the first communication passage, and the second hole has a small flow passage area of the second communication passage. The first hole and the second hole are arranged.

In the third damping force variable shock absorber of the present invention, the valve means in the first or second damping force variable shock absorber is stopped at the fourth position, and the valve means is stopped at the fourth position. In this case, the first hole and the second hole are arranged such that the first hole has a large flow passage area and the second hole has a middle position with the flow passage area of the second communication passage. The holes are arranged.

In the fourth damping force variable shock absorber of the present invention, the valve means in any one of the first to third damping force variable shock absorbers stops at the fifth position, and the valve means moves to the fifth position. When stopped, the first hole is positioned so that the flow path area of the first communication passage is in the middle and the second hole is in a position where the flow path area of the second communication passage is large. A second hole is arranged.

In the fifth damping force variable shock absorber of the present invention, the valve means in any one of the first to fourth damping force variable shock absorbers stops at the sixth position, and the valve means moves to the sixth position. When stopped, the first hole has a small flow passage area of the first communication passage, and the second hole has the first passage so that the flow passage area of the second communication passage is in the middle. A second hole is arranged.

In the sixth damping force variable shock absorber of the present invention, the valve means in any one of the first to fifth damping force variable shock absorbers stops at the seventh position, and the valve means moves to the seventh position. When stopped, the first hole is positioned so that the flow path area of the first communication passage is in the middle and the second hole is in a position where the flow path area of the second communication passage is small. A second hole is arranged.

On the other hand, the first damping force variable shock absorber control device of the present invention comprises a speed calculating means for calculating the vertical speed on the spring, a running state detecting means for detecting the running state of the vehicle, and a working fluid pool. And a piston member that is slidably provided in the cylinder and divides the inside of the cylinder into an upper chamber and a lower chamber, and a first fluid passage for allowing working fluid to flow from the upper chamber to the lower chamber. Communication passage, a second communication passage that allows the working fluid to flow from the lower chamber to the upper chamber, a first hole that adjusts the flow passage area of the first communication passage, and a second communication passage. Second to adjust the flow passage area
And a valve means for stopping at the first position, the second position, and the third position, the first hole being at the first position when the valve means is stopped at the first position. When the flow passage area of the communication passage is small, the second hole is at a position where the flow passage area of the second communication passage is small, and when the valve means is stopped at the second position, it is the first position.
Of the first communication passage has a small flow passage area, and the second hole has a large flow passage area of the second communication passage.
When stopped at the position, the first hole has a large flow passage area of the first communication passage, and the second hole has a small flow passage area of the second communication passage. A damping force variable shock absorber characterized in that a first hole and a second hole are arranged, a vertical velocity value on a spring calculated by the speed calculating means, and the traveling state detecting means. A damping force variable shock absorber control device comprising: a changing unit that operates the valve unit according to a traveling state of the vehicle.

A second damping force variable shock absorber control device of the present invention is provided with a speed calculating means for calculating a vertical speed on a spring, a cylinder storing a working fluid, and a slidable inside the cylinder. And a piston member that divides the interior of the cylinder into an upper chamber and a lower chamber, a first communication passage that allows the working fluid to flow from the upper chamber to the lower chamber, and a lower chamber to the upper chamber. A second communication passage that allows the working fluid to flow, a first hole that adjusts the flow passage area of the first communication passage, and a second hole that adjusts the flow passage area of the second communication passage are arranged. , Valve means for stopping at a first position, a second position, and a third position, the valve means being the first
When stopped at the position, the first hole has a large flow passage area of the first communication passage, the second hole has a large flow passage area of the second communication passage, and the valve means has the second flow passage area. When stopped at the position, the first hole reduces the flow passage area of the first communication passage and the second hole decreases the second area.
When the valve means stops at a position where the flow passage area of the communication passage is large and the valve means stops at the third position, the first hole has a large flow passage area and the second hole has a large flow passage area. A damping force variable shock absorber characterized in that the first hole and the second hole are arranged so that the flow passage area of the two communication passages is small, and the damping force variable shock absorber is calculated by the speed calculation means. Changing means for actuating the valve means according to the value of the vertical velocity on the spring and the running state of the vehicle detected by the running state detecting means.

A third damping force variable shock absorber control device of the present invention is, in the second damping force variable shock absorber control device, provided with a running state detecting means for detecting a running state of the vehicle, and the changing means is a speed calculating means. The valve means is operated according to the value of the vertical velocity on the spring calculated by the above and the traveling state of the vehicle detected by the traveling state detecting means.

[0019]

According to the first damping force variable shock absorber of the present invention having the above-mentioned structure, the positions of the first hole and the second hole are different depending on the stop position of the valve means, so that the damping force on the extension side and the contraction side on the contraction side are different. The damping force of is different. That is, when the valve means is stopped at the first position, the first hole has a small flow passage area of the first communication passage, and the second hole has a small flow passage area of the second communication passage. Therefore, the damping force on the extension side and the damping force on the contraction side both increase. When the valve means is stopped at the second position, the first hole is in a position where the flow passage area of the first communication passage is small, and the second hole is in a position where the flow passage area of the second communication passage is large. Therefore, the damping force on the extension side is large and the damping force on the contraction side is small. When the valve means is stopped at the third position, the first hole is at a position where the flow passage area of the first communication passage is large and the second hole is at a position where the flow passage area of the second communication passage is small. Therefore, the damping force on the extension side is small and the damping force on the contraction side is large.

In the second variable damping force shock absorber of the present invention, the positions of the first hole and the second hole differ depending on the stop position of the valve means, so that the damping force on the extension side and the damping force on the contraction side are different. Is different. That is, when the valve means is stopped at the first position, the first hole has a large flow passage area of the first communication passage, and the second hole has a large flow passage area of the second communication passage. Therefore, both the damping force on the extension side and the damping force on the contraction side are small. When the valve means is stopped at the second position, the first hole is in a position where the flow passage area of the first communication passage is small, and the second hole is in a position where the flow passage area of the second communication passage is large. Therefore, the damping force on the extension side is large and the damping force on the contraction side is small. When the valve means is stopped at the third position, the first hole is at a position where the flow passage area of the first communication passage is large and the second hole is at a position where the flow passage area of the second communication passage is small. Therefore, the damping force on the extension side is small and the damping force on the contraction side is large.

In the third damping force variable shock absorber of the present invention, when the valve means is stopped at the fourth position, the first hole has a large flow passage area of the first communication passage and the second hole has Second
Since the flow path area of the communication passage is in the middle, the damping force on the extension side is small and the damping force on the contraction side is medium.

In the fourth damping force variable shock absorber of the present invention, when the valve means stops at the fifth position, the first hole has the flow passage area of the first communication passage, and the second hole has Second
Since the flow path area of the communication passage is large, the damping force on the extension side is moderate and the damping force on the contraction side is small.

In the fifth damping force variable shock absorber of the present invention, when the valve means is stopped at the sixth position, the first hole has a small flow passage area of the first communication passage, and the second hole has Second
Since the flow path area of the communication passage is in the middle, the damping force on the extension side is large and the damping force on the contraction side is medium.

In the sixth damping force variable shock absorber of the present invention, when the valve means is stopped at the seventh position, the first hole has the flow passage area of the first communication passage, and the second hole has Second
Since the flow path area of the communication passage is small, the damping force on the extension side is moderate and the damping force on the contraction side is large.

On the other hand, in the first damping force variable shock absorber control device of the present invention, depending on the vertical speed on the spring calculated by the speed calculating means and the running state of the vehicle detected by the running state detecting means, The modifying means actuates the valve means. Then, when the valve means is stopped at the first position, the first hole makes the flow passage area of the first communication passage small, and the second hole makes the flow passage area of the second communication passage small. Therefore, the damping force on the extension side and the damping force on the contraction side both increase. When the valve means stops at the second position, the first hole reduces the flow passage area of the first communication passage, and the second hole decreases the second area.
Since it is located at a position where the flow passage area of the communication passage is large, the extension side damping force is large and the contraction side damping force is small. When the valve means is stopped at the third position, the first hole is at a position where the flow passage area of the first communication passage is large and the second hole is at a position where the flow passage area of the second communication passage is small. Therefore, the damping force on the extension side is small and the damping force on the contraction side is large.

In the second damping force variable shock absorber controller of the present invention, the changing means actuates the valve means in accordance with the vertical speed on the spring calculated by the speed calculating means. Then, when the valve means is stopped at the first position, the first hole has a large flow passage area of the first communication passage, and the second hole has a large flow passage area of the second communication passage. Therefore, both the damping force on the extension side and the damping force on the contraction side are small.
When the valve means is stopped at the second position, the first hole is in a position where the flow passage area of the first communication passage is small, and the second hole is in a position where the flow passage area of the second communication passage is large. Therefore, the damping force on the extension side is large and the damping force on the contraction side is small. Third valve means
When stopped at the position of, the first hole has a large flow passage area of the first communication passage, and the second hole has a small flow passage area of the second communication passage. The damping force of is small and the damping force on the contracting side is large.

According to the third damping force variable shock absorber control device of the present invention, the second damping force variable shock absorber control device is provided with the traveling state detecting means for detecting the traveling state of the vehicle, and the speed calculating means The changing means actuates the valve means in accordance with the running state of the vehicle detected by the running state detecting means in addition to the calculated vertical speed on the spring.

The above-mentioned position where the flow passage area is small is a position where the flow passage area is substantially minimized and includes the case where the flow passage area is zero. The position where the flow passage area is large is a position where the flow passage area is substantially maximized. The position where the flow path area is in the middle is any position between the position where the flow path area is small and the position where the flow path area is large.

[0029]

Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a block diagram showing the overall configuration of the first embodiment. 1 is a known strain gauge type acceleration sensor,
Each wheel is attached to the vehicle body near the suspension upper support (not shown). This acceleration sensor 1
Detects the vertical acceleration on the spring, and the detection signal is input to the integrating circuit 2 and the high-pass filter 3. The integrating circuit 2 integrates the vertical acceleration signal on the spring from the acceleration sensor 1 to obtain the speed signal V (=
Calculate dx2). When the vertical acceleration on the spring detected by the acceleration sensor 1 is input to the high pass filter 3, a high frequency vibration level Fh, which is a component having a frequency higher than the sprung resonance frequency by a predetermined frequency or more, is extracted. The control unit 5 inputs a signal from the integrating circuit 2 and the high-pass filter 3 and outputs a control signal to the actuator 6, and is configured as an arithmetic logic circuit. Reference numeral 7 is a shock absorber, and 6 is an actuator for driving a control valve 10 provided in the shock absorber 7.

Next, the structure of the shock absorber 7 is shown in FIGS.
This will be described with reference to FIG. (A) in each figure shows the longitudinal cross-sectional view of the shock absorber. In FIG. 2 (a),
The middle space of the cylinder 101 of the shock absorber 7 is vertically divided by the main piston 102 into an upper liquid chamber 1a and a lower liquid chamber 1b, respectively. The main piston 102 is fixed to a piston rod 103 passing through the center.

The main piston 102 has a main flow passage 13 formed through the outer periphery thereof, and the plate check valves 10 are provided on the upper surface and the lower surface of the main piston 102, respectively.
It is opened and closed by 7, 108. Piston rod 103
A sub-flow passage 14 is formed inside to allow the working oil to flow between the upper liquid chamber 1a and the lower liquid chamber 1b.

The spring 112 and the plate 113 are provided inside the housing 111. This plate 11
3, an expansion side damping force hole is provided in the inner peripheral portion, and a contraction side damping force hole is provided in the outer peripheral portion, and moves up and down inside the housing 111 by changing the flow direction of the hydraulic oil. The housing 111, the spring 112, and the plate 113 are means for changing the flow passage area of the sub-flow passage 14 independently and easily on the expansion side and the contraction side. Since it can be realized also by the expansion side dedicated hole 16, it may be omitted.

2 to 6 (b) are transverse sectional views of the contraction side flow passage obtained by cutting the piston member of FIG. 2 (a) in the AA direction, and FIG. 2 (c) is a piston of FIG. 2 (a). The cross-sectional view of the extension side flow path which cut | disconnected the member to BB direction is shown. In addition, the arrow shown by the solid line in the figure represents the flow of hydraulic oil.

The lower end portion of the piston rod 103 is formed in a cylindrical shape, and the control valve 10 and the contraction-side dedicated flow path 1 are provided in the cylinder.
1. The expansion-side dedicated flow path 12 is provided, and the contraction-side dedicated flow path 11 and the expansion-side dedicated flow path 12 are opened and closed by the plate-like check valves 109 and 110 provided on the piston rod 103, respectively, to form the upper liquid chamber. Communicate with.

The control valve 10 is connected to an actuator (not shown), and can be rotated about the central axis of the piston rod 103 by driving the actuator. The control valve 10 is provided with a contraction-side exclusive hole 15 and an expansion-side exclusive hole 16, and the rotation of the control valve 10 causes the inside of the control valve 10 as shown in FIGS. 2B and 2C. Sub-channel 14 and shrink-side channel 1
1. It is possible to connect or cut off the extension-side dedicated flow path 12. The contraction-side dedicated channel 11, the expansion-side dedicated channel 12, the contraction-side dedicated hole 15, and the expansion-side dedicated hole 16 are formed facing each other, and the contraction-side dedicated channel 11 and the expansion-side dedicated channel 12 are opposed to each other. Although it is formed at a position with a rotation angle of 0 °, the contraction side dedicated hole 15 and the extension side dedicated hole 16 have a relative rotation angle of 45 °.
Is formed at the position.

Therefore, the auxiliary flow passage 14 in the control valve 10 and the exclusive flow passage 11 in the contraction side communicate with each other through the exclusive contraction hole 15, and the auxiliary flow passage in the control valve 10 through the exclusive expansion hole 16. 14 and the expansion-side dedicated flow path 12 communicate with each other, the hydraulic oil flows through the main flow path 13 and the sub-flow path 14 as shown in FIG. Condition). Control valve 1 through the contraction side exclusive hole 15
4 shows a case where the sub-flow passage 14 in 0 and the contraction-side dedicated flow passage 11 communicate with each other and the control valve 10 blocks the sub-flow passage 14 in the control valve 10 and the expansion-side dedicated flow passage 12 from each other. As described above, since the hydraulic oil flows, the flow path from the upper liquid chamber 1a to the lower liquid chamber 1b becomes smaller than the flow path from the lower liquid chamber 1b to the upper liquid chamber 1a, and the contraction side damping force is small and the expansion side is small. The damping force increases (state). The control valve 10 allows the sub-flow passage 14 and the contraction-side dedicated flow passage 11 in the control valve 10.
Is shut off, and the control valve 10
When the sub-flow passage 14 in the inside and the extension-side dedicated flow passage 12 are in communication with each other, the hydraulic fluid flows as shown in FIG. 5, so that the flow passage from the lower liquid chamber 1b to the upper liquid chamber 1a is the upper liquid chamber. It becomes smaller than the flow path from 1a to the lower liquid chamber 1b, the extension side damping force is small, and the contraction side damping force is large (state). When the control valve 10 shuts off the sub-flow passage 14 in the control valve 10 and the contraction-side dedicated flow passage 11 and shuts off the sub-flow passage 14 in the control valve 10 and the expansion-side dedicated flow passage 12, As shown in FIG. 6, the hydraulic oil flows through the passage 13 and a large damping force is exerted on both the contraction side and the extension side (state).

In this embodiment, the state of corresponds to the first position of claims 2 and 8, and the state of claim 1 corresponds to the first position.
It corresponds to the second position of 2, 7, and 8, the state of corresponds to the third position of claims 1, 2, 7 and 8, and the state of corresponds to the first position of claims 1 and 8. To do.

These damping forces can be changed by operating the control valve 10 by an actuator to connect or disconnect the sub-flow passage 14 in the control valve 10 with the contraction-side dedicated passage 11 and the extension-side dedicated passage 12. You can

Table 1 shows the relationship between the control valve position 10 and the damping force described above.

[0040]

[Table 1] With the configuration as described above, the control valve 10 is controlled to change the state from the above state to the control valve 10
By rotating, the contraction-side damping force can be arbitrarily controlled while keeping the expansion-side damping force small. By rotating the control valve 10 from this state to the state described above, the expansion-side damping force can be arbitrarily controlled while the contraction-side damping force is increased.

The control by the control unit 5 and the operation of the damping force variable shock absorber by this control in the above configuration will be described with reference to the drawings. Here, each state quantity (displacement of vehicle body and tire, velocity, acceleration) is positive upward.

In the control of this embodiment, the damping force is large when the damping force of the shock absorber exerts a damping action on the movement of the vehicle body, and the damping force is small when the damping force excites the movement of the vehicle body. To do it. Specifically, when the sprung speed is positive, the expansion side damping force of the shock absorber may be increased and the contraction side damping force may be decreased. Therefore, as shown in FIG. Then, the control valve 10 is rotated (state). Further, when the sprung speed is negative, the expansion side damping force of the shock absorber may be made small and the contraction side damping force may be made large. Therefore, as shown in FIG. 10 is rotated (state).

The control by the control unit 5 will be described in detail below with reference to a flow chart. First, step S1 in FIG.
At 0, the control unit 5 is initialized. Step S30
Then, the high frequency vibration level Fh from the high pass filter 3
Take in.

In step S40, it is determined whether the high frequency vibration level Fh calculated in step S30 is higher than the high frequency vibration level threshold f1. Here, if YES is determined, the process proceeds to step S110, and the damping force is reduced on both the contraction side and the extension side so that the unsprung vibration can be efficiently absorbed by the shock absorber. That is, if YES is determined in step S40, the control unit 5 drives the actuator so that the control valve 10 is in the position (state) shown in FIG.

If NO is determined in step S40, the process proceeds to step S50. In step S50, the integration circuit 2
The sprung speed signal V from is taken in. In step S60, the sprung mass velocity signal V is set to the sprung mass velocity threshold value v1 (v1
> 0) is determined. If YES is determined here, the process proceeds to step 100, where the contraction side damping force of the shock absorber is made small and the extension side damping force is made large. That is, the actuator is driven so that the control valve 10 is in the position (state) shown in FIG.

If NO is determined in step S60, the process proceeds to step S70. In step S70, it is determined whether the sprung mass velocity signal V is smaller than the sprung mass velocity threshold value v2 (v2 <0). If YES is determined here, the process proceeds to step S90, where the expansion side damping force of the shock absorber is reduced and the contraction side damping force is increased. That is, the actuator is driven so that the control valve 10 is in the position (state) shown in FIG.

If NO in step S70, the process proceeds to step S80. In step S80, it is possible to determine that the sprung mass is stable when the sprung mass velocity signal V is close to 0. Therefore, even if a sudden external force is applied, the damping force can be absorbed by the shock absorber on both the compression side and the extension side. To be small. That is, the control valve 10 is shown in FIG.
Drive the actuator to the position (state) shown in. Note that steps S40, S60, S70
In the determination of, the threshold is provided with hysteresis in order to prevent the divergence of the control system.

When the processes in steps S80 to S110 are completed, the process returns to step S30. When the above process is executed, the relationship between the absolute speed on the spring and the relative speed between the sprung and unsprung springs is as shown in FIG.

As described above, in the present embodiment, the damping force of the shock absorber can be changed only by the signal from the sprung acceleration sensor 1, and the damping force can be changed only by the vertical speed on the spring. Since it is sufficient to make a determination, it is possible to realize control close to that of a skyhook damper without requiring high-speed followability.

In this embodiment, the integrating circuit 2 corresponds to speed calculating means, the control section 5 corresponds to changing means, the high-pass filter 3 corresponds to running state detecting means, and the control valve 10 corresponds to valve means. However, the expansion-side dedicated channel 11 is the first
Corresponding to the communication passage, the contraction-side dedicated flow path 12 corresponds to the second communication passage, the extension-side dedicated hole 16 corresponds to the first hole, and the contraction-side dedicated hole 15 corresponds to the second hole. ..

Next, a second embodiment will be described. The damping force variable shock absorber of the second embodiment is partially different in structure from the first embodiment, and the second embodiment will be described focusing on the difference in the structure of this shock absorber 7A.

In FIG. 9 (a), the middle space of the cylinder 10 of the shock absorber 7A is vertically divided by the main piston 20 into an upper liquid chamber 2a and a lower liquid chamber 2b, respectively. The main piston 20 is fixed to a piston rod 30 passing through the center.

The main piston 20 has a main flow passage 40 formed through the outer periphery thereof, and plate check valves 48 and 4 provided on the upper and lower surfaces of the main piston 20, respectively.
It is opened and closed by 9. A sub-flow passage 50 is formed in the piston rod 30 to allow the working oil to flow between the upper liquid chamber 2a and the lower liquid chamber 2b.

9 and 12 to 15 (b) are transverse cross-sectional views of the contraction side flow passage obtained by cutting the piston member of FIG. 9 (a) in the AA direction. (C) in each figure is shown in FIG. 9 (a). 4) is a transverse cross-sectional view of the extension side flow path obtained by cutting the piston member of FIG. In addition, the arrow shown by the solid line in the figure represents the flow of hydraulic oil.

The lower end of the piston rod 30 is formed in a tubular shape, and the control valve 60 and the contraction-side dedicated flow path 5 are provided in the inside of the cylinder.
6. The expansion-side dedicated flow path 57 is provided, and the contraction-side dedicated flow path 56 and the expansion-side dedicated flow path 57 are opened and closed by the plate-like check valves 58 and 59 provided on the piston rod 30, respectively.
It communicates with the upper liquid chamber 2a.

The control valve 60 is connected to an actuator (not shown), and can be rotated about the central axis of the piston rod 30 by driving the actuator. 9D is a vertical cross-sectional view of the control valve 60, the lower end of the control valve 60 has a hollow structure as shown in the figure. The control valve 60 is provided with a contraction-side dedicated hole 66 and an extension-side dedicated hole 67, and the rotation of the control valve 60 causes the control valve 60 to rotate, as shown in FIGS.
As shown in FIG. 11, the auxiliary flow passage 50 in the control valve 60, the contraction-side flow passage 56, and the expansion-side flow passage 57 can be connected or disconnected. Another example of the contraction-side dedicated channel 56, the extension-side dedicated channel 57, the contraction-side dedicated hole 66, and the extension-side dedicated hole 67 is shown in FIGS. 10 (a), 10 (b), and 10 (c). Here, the contraction side maximum communication area ST and the extension side maximum communication area SN in FIG. 11 determine the minimum damping force on the flow path side, and the relationship between ST and SN is arbitrary.
In the figure, points a and b, points c and d, points e and f, and points g and h may be connected by a straight line or a curve. The characteristics of FIG. 11 are mainly determined by the shapes of the contraction-side dedicated channel 56, the extension-side dedicated channel 57, the contraction-side dedicated hole 66, the extension-side dedicated hole 67, and the like. As is clear from FIGS. 11A and 11B, it is possible to change the flow passage area of the other communication passage while keeping the flow passage area of the one communication passage at the maximum. Further, in FIG. 11A, when the valve rotation angle is θg or less or θe or more, the flow passage areas of both communication passages can be set to 0.
In this embodiment, in FIG. 11, any position between a and b corresponds to the fourth position in claim 3, and any position between c and d corresponds to the fifth position in claim 4. Corresponding, e, f
Any position in between corresponds to the sixth position in claim 5,
Any position between g and h corresponds to the seventh position in claim 6, any position between e and g corresponds to the first position in claims 1 and 7, and any position between a and h The position corresponds to the third position in claims 1, 2, 7 and 8, any position between b and d corresponds to the first position in claims 2 and 8, and any position between c and f. The position of corresponds to the second position of claims 1, 2, 7 and 8.

Thus, the auxiliary flow passage 50 in the control valve 60 and the exclusive compression flow passage 56 communicate with each other through the contraction-side exclusive hole 66, and the auxiliary flow path inside the control valve 60 through the extension-side exclusive hole 67. When the flow path 50 and the expansion-side dedicated flow path 57 are in communication with each other, the hydraulic oil flows through the main flow path 40 and the sub flow path 50 as shown in FIG. Condition). Control valve 6 through the contraction-side dedicated hole 66
13 shows the case where the sub-flow passage 50 in 0 and the contraction-side dedicated flow passage 56 communicate with each other and the control valve 60 blocks the sub-flow passage 50 in the control valve 60 and the extension-side dedicated flow passage 57. As described above, since the hydraulic fluid flows, the flow path from the upper liquid chamber 2a to the lower liquid chamber 2b becomes smaller than the flow path from the lower liquid chamber 2b to the upper liquid chamber 2a, and the compression force on the contraction side is small and the expansion side is small. The damping force increases (state). By the control valve 60, the sub-flow passage 50 in the control valve 60 and the contraction-side dedicated flow passage 5
6 is cut off, and the control valve 6
When the sub-flow channel 50 in 0 and the extension-side dedicated flow channel 57 are in communication with each other, the hydraulic oil flows as shown in FIG. 14, so that the flow channel from the lower liquid chamber 2b to the upper liquid chamber 2a is the upper liquid. It becomes smaller than the flow path from the chamber 2a to the lower liquid chamber 2b, the expansion-side damping force is small, and the contraction-side damping force is large (state).
By the control valve 60, the sub-flow path 50 in the control valve 60
And the contraction-side dedicated flow path 56 is blocked, and the control valve 60
In the case where the sub-flow passage 50 and the expansion-side dedicated flow passage 57 inside are blocked (FIG. 15), only the hydraulic oil flows through the main flow passage 40, and a large damping force is generated on both the contraction side and the expansion side. (State of). In addition, by moving the valve to any intermediate value between these four states, either the contraction side damping force or the extension side damping force is held at the maximum or minimum, while the other damping force can be taken to the maximum value. It can be arbitrarily selected from between and.

These damping forces can be changed by operating the control valve 60 by an actuator to connect or disconnect the auxiliary flow passage 50, the contraction side dedicated flow passage 56, and the expansion side dedicated flow passage 57 in the control valve 60. You can

Table 2 shows the relationship between the position of the control valve 60 and the damping force explained above.

[0060]

[Table 2] In the above configuration, the control by the control unit 5 and the operation of the damping force variable shock absorber by this control are
It will be described with reference to the drawings. As in the first embodiment, each state quantity (displacement of vehicle body and tire, speed, acceleration) is positive in the upward direction, and each state quantity is positive in the upward direction in the third and subsequent embodiments described below. ..

In the control of the present embodiment, the damping force is increased when the damping force of the shock absorber exerts a damping action on the movement of the vehicle body, and is reduced when the damping force excites the movement of the vehicle body. The point is the same as that of the first embodiment, but in the present embodiment, the magnitude of the damping force when the vibration damping action is further performed is selected according to the situation. Specifically, when the sprung speed is positive, the expansion side damping force of the shock absorber may be increased and the contraction side damping force may be decreased. Therefore, in FIG. 11, the control valve 60 is rotated to the rotation angle plus side. For example, when there is a lot of high-frequency vibration on the spring and a rugged feeling is worrisome, the positive-side rotation angle of the control valve 60 is set to a small value to slightly reduce the extension-side damping force that acts as the vibration damping function. Realizes compatibility with sprung mass damping while weakening high-frequency vibration transmission. Further, when the sprung speed is negative, the compression side damping force of the shock absorber may be increased and the extension side damping force may be decreased. Therefore, in FIG. 11, the control valve 60 is rotated to the minus side of the rotation angle. If there is a lot of high-frequency vibration and you feel uncomfortable, the negative side rotation angle of the control valve 60 is set to a small value to slightly reduce the contraction-side damping force that acts as the above-mentioned vibration suppressing effect, and the high-frequency vibration is transmitted. Achieves both sprung mass damping while weakening.

The control by the control unit 5 will be described in detail below with reference to the flow chart. First, step S in FIG.
At 300, the control unit 5 is initialized. Step S
At 310, the sprung vertical acceleration high frequency component G from the high pass filter 3 is fetched.

In steps S320 to S360, the magnitude of the sprung vertical acceleration high frequency component G is represented by the counter C. The state of this conversion is shown in FIG. Based on the value of the counter C, in step S370, the rotation angle θ + of the control valve 60, which selects one from the maximum and the minimum that can reduce the contraction side damping force and the extension side damping force, and the extension side damping force are selected. The rotation angle θ- of the control valve 60, which is selected from the maximum and the minimum that can take a small contraction damping force, is determined. At this time, the counter C and θ + have a negative correlation, and the counter C and θ− have a positive correlation.

In step S380, the sprung mass velocity signal V from the integrating circuit 2 is fetched. In step S390,
The sprung mass velocity signal V is the sprung mass velocity threshold value v1 (v1>
0) It is determined whether or not it is greater than. If YES is determined here, the process proceeds to step S430, and the control valve 60 is rotated by the rotation angle θ + determined in step S370.

If NO at step S390,
It proceeds to step S400. In step S400, it is determined whether the sprung mass velocity signal V is smaller than the sprung mass velocity threshold value v2 (v2 <0). If YES is determined here, the process proceeds to step S420, and the control valve 60 is rotated by the rotation angle θ− determined in step S370.

If NO at step S400,
It proceeds to step S410. In step S410, it can be determined that the sprung mass is stable when the sprung mass velocity signal V is close to 0. Therefore, even if a sudden external force is applied, the damping force can be absorbed by the shock absorber on both the contraction side and the extension side. To be small. That is, the control valve 6
The rotation angle of 0 is 0 °.

When the processes in steps S410 to S430 are completed, the process returns to step S310. When the above processing is executed, the relationship between the absolute speed on the sprung and the relative speed between the sprung and the unsprung is as shown in FIG. 18. In the present embodiment, the damping force of the damping portion is the high frequency vibration on the spring. It can be changed according to the size of. The state in FIG. 18 is realized by the rotation angle 0 ° of the control valve 60, the state is realized by the rotation angle θ + of the control valve 60, and the state is realized by the rotation angle θ− of the control valve 60. To be realized.

Next, a third embodiment will be described. FIG. 19
FIG. 11 is a block diagram showing the overall configuration of the third embodiment. In the third embodiment, in addition to the first and second embodiments shown in FIG.
It is characterized in that it is provided with a known vehicle speed sensor 8 as a running state detecting means and an input device 9 for the driver to input a preference of hard or soft, and the other configurations are substantially the same as those of the second embodiment. There is. As an example of an input method to the input device 9, a method of selecting one of two of “Normal” for performing control and “Hard” for increasing both the expansion-side damping force and the contraction-side damping force by a switch may be used. .. Therefore, the control unit 5, which is configured as an arithmetic logic circuit, inputs signals from the integration circuit 2, the high-pass filter 3, the vehicle speed sensor 8, and the preference input device 9, and outputs a control signal to the actuator 6.

The control by the control unit 5 and the operation of the damping force variable shock absorber by this control in the above configuration will be described with reference to the drawings. In the control of the present embodiment, as in the first and second embodiments, when the damping force of the shock absorber exerts a damping action on the movement of the vehicle body, the damping force is large, and the damping force excites the movement of the vehicle body. When the vehicle speed is above a certain level,
Alternatively, this is not the case when the high-frequency vibration level is above a predetermined level. Specifically, when the sprung speed is positive, the expansion side damping force of the shock absorber may be made large and the contraction side damping force may be made small. Therefore, in FIG.
0 is rotated to the plus side of the rotation angle, but at this time, the control valve 60 is rotated according to the value of the sprung speed. Further, when the sprung speed is negative, the compression side damping force of the shock absorber may be increased and the extension side damping force may be decreased. Therefore, in FIG. 11, the control valve 60 is rotated to the minus side of the rotation angle. The control valve 60 is rotated according to the value of the upper speed. For example, by making the sprung speed proportional to the rotation angle, when the degree of sprung vibration is large, the damping force is increased to enhance the damping effect, and when the degree of sprung vibration is small, the damping force is compared. It achieves compatibility with sprung mass damping while weakening the transmission of high-frequency vibrations by making it as small as possible.

Also, different control may be performed when the vehicle speed is equal to or higher than a predetermined value or when the driver's preference is "hard". In FIG. 11A, when the vehicle speed is equal to or higher than a predetermined value or when the driver's preference is “hard”, the valve rotation angle is set to θd or θu, and both the extension damping force and the compression damping force are set. It can be increased to improve steering stability. Further, in FIG. 11 (b), the basic position of the valve may be set to θ6 + and the extension side damping force or the contraction side damping force may be reduced according to the value of the high frequency vibration level.

Hereinafter, the control by the control unit 5 when the damping force is switched in 13 stages will be described in detail with reference to the flowcharts of FIGS. 20, 21, and 22 and the damping force setting diagram of FIG. First, in step S500 of FIG. 20, the control unit 5 is initialized. In step S510, whether the driver's preference is "Normal" or "Hard" is acquired. Here, "Normal" means the above "softening", and "Hard" means the above "hardening".

At step S520, whether the preference fetched at step S510 is "Normal" or "Har".
It is determined whether it is "d". If it is determined to be "Hard", the process proceeds to step S800. Step S800
Is further subdivided, and its internal flowchart is shown in FIGS. 21 and 22 will be described later.

If it is determined to be "Normal" in step S520, the process proceeds to step S530. Step S53
At 0, the vehicle speed Vcar, which is the signal from the vehicle speed sensor 8, is fetched. In step S540, it is determined whether the vehicle speed Vcar acquired in step S530 is higher or lower than the vehicle speed threshold value Tcar. If it is determined that the vehicle speed Vcar is greater than the vehicle speed threshold value Tcar, step S
Proceed to 800.

In step S550, the sprung mass velocity signal V from the integrating circuit 2 is fetched. In step S560,
It is determined whether the sprung mass velocity signal V is larger than the sprung mass velocity threshold value Vref3 +. If YES is determined here,
In step S710, the compression side damping force of the shock absorber is set to soft and the extension side damping force is set to hard3. That is, the actuator is driven so that the control valve 60 is at the position of θ3 + shown in FIG.

If NO at step S560,
It proceeds to step S570. In step S570, it is determined whether the sprung mass velocity signal V is larger than the sprung mass velocity threshold Vref2 +. If YES is determined here, the process proceeds to step S720, and the contraction side damping force of the shock absorber is set to soft and the extension side damping force is set to hard 2. That is, the actuator is driven so that the control valve 60 is at the position of θ2 + shown in FIG.

If NO at step S570,
It proceeds to step S580. In step S580, it is determined whether the sprung mass velocity signal V is larger than the sprung mass velocity threshold Vref1 +. If YES is determined here, the process proceeds to step S730, and the contraction side damping force of the shock absorber is set to soft and the extension side damping force is set to hard 1. That is, the actuator is driven so that the control valve 60 is at the position of θ1 + shown in FIG.

If NO at step S580,
It proceeds to step S590. In step S590, it is determined whether the sprung mass velocity signal V is larger than the sprung mass velocity threshold Vref1-. If YES is determined here, the process proceeds to step S740, and both the compression side damping force and the extension side damping force of the shock absorber are made soft. That is, the actuator is driven so that the control valve 60 is at the 0 ° position shown in FIG.

If NO at step S590,
It proceeds to step S600. In step S600, it is determined whether the sprung mass velocity signal V is greater than the sprung mass velocity threshold value Vref2-. If YES is determined here, the process proceeds to step S750, and the contraction side damping force of the shock absorber is set to hard 1 and the extension side damping force is set to soft. That is, the actuator is driven so that the control valve 60 is at the position of θ1- shown in FIG.

If NO at step S600,
It proceeds to step S610. In step S610, it is determined whether the sprung mass velocity signal V is larger than the sprung mass velocity threshold Vref3-. If YES is determined here, the process proceeds to step S760, and the contraction side damping force of the shock absorber is set to hard 2 and the extension side damping force is set to soft. That is, the actuator is driven so that the control valve 60 is at the position of θ2- shown in FIG.

If NO at step S610,
In step S770, the compression side damping force of the shock absorber is set to hard 3 and the extension side damping force is set to soft. That is, the actuator is driven so that the control valve 60 is at the position of θ3- shown in FIG.

By performing the processing of FIG. 20 described above, the extension damping force and the compression damping force are switched according to the magnitude of the sprung mass velocity signal V as shown in FIG.
Specifically, as the sprung speed signal V increases, the contraction-side damping force keeps the minimum state and the extension-side damping force increases, while as the sprung speed signal V decreases (negative side). The larger the value becomes, the smaller the extension-side damping force is, while the contraction-side damping force increases. Therefore, fine damping force control can be realized according to the magnitude of the sprung mass velocity signal V.

Next, step S800 will be described with reference to FIG. In this step S800, the damping force is basically set to be hard in consideration of traveling stability, and the extension side damping force and the contraction side damping force are switched according to the high frequency vibration level Fh.

Step S520 or step S5
If YES is determined in step S40, the process proceeds to step S801 to capture the high frequency vibration level Fh. Then, step S8
Go to 10. In step S810, it is determined whether the high frequency vibration level Fh is higher than the high frequency vibration level threshold Tf2. If YES is determined here, a step S is performed.
In step 830, it is determined whether the sprung mass velocity signal V is larger than the sprung mass velocity threshold Vref1 +. Where YES
If it is determined that the actuator is driven, the process proceeds to step S1010, and the actuator is driven so that the control valve 60 becomes the position of θ4 + shown in FIG. 11 (b).

If NO in step S830,
In step S840, it is determined whether the sprung mass velocity signal V is smaller than the sprung mass velocity threshold value Vref1-. Here, if the determination is YES, the process proceeds to step S1030,
The actuator is driven so that the control valve 60 comes to the position of θ8 + shown in FIG. 11 (b).

If NO at step S840,
Proceeding to step S1000, the control valve 60 is moved to the position shown in FIG.
The actuator is driven to the position of θ6 + shown in (b).

If NO in step S810, the process proceeds to step S820. In step S820, the high frequency vibration level Fh is equal to the high frequency vibration level threshold Tf1 (Tf1
It is determined whether or not it is larger than <Tf2). If YES is determined here, the process proceeds to step S850 to determine whether the sprung mass velocity signal V is larger than the sprung mass velocity threshold Vref1 +. Here, if the determination is YES, step S1
Proceeding to 020, the control valve 60 changes to θ shown in FIG.
Drive the actuator so that it is in the 5+ position.

If NO at step S850,
In step S860, it is determined whether the sprung mass velocity signal V is smaller than the sprung mass velocity threshold value Vref1-. Here, if the determination is YES, the process proceeds to step S1040,
The actuator is driven so that the control valve 60 is at the position of θ7 + shown in FIG. 11 (b).

If NO at step S860,
Proceeding to step S1000, the control valve 60 is moved to the position shown in FIG.
The actuator is driven to the position of θ6 + shown in (b).

If NO in step S820,
Proceeding to step S1000, the control valve 60 is moved to the position shown in FIG.
The actuator is driven to the position of θ6 + shown in (b).

Steps S700 to S770 and S1000
When the processing in S1050 is completed, step S5
Return to 10. By performing the processing of FIG. 21 as described above, even if the damping force should be set hard according to the vehicle speed and the driver's preference, according to the high frequency vibration level Fh that reflects the fine unevenness of the road surface, Switching between extension side damping force and contraction side damping force. Specifically, if the sprung speed signal V is constant, the contraction side damping force or the extension side damping force is decreased as the high frequency vibration level Fh increases. Therefore, it is possible to suppress the transmission of high-frequency vibrations due to the unevenness of the road surface while damping the movement of the vehicle body.

Note that, in FIG. 21, after the determination in step S810 and step S820 is Yes, the case is divided into three stages depending on the sprung speed, but as shown in FIG. 22, it may be divided into five stages. However, the valves may be continuously switched according to the sprung speed. It goes without saying that more detailed control can be realized by these.

In the present embodiment, the high frequency vibration level Fh is taken in, but it is not necessary. In this case, step S520 or step S54
If YES is determined in 0, the process jumps to step S1000.

By using the shock absorber having the above structure, for example, the rotation angle θ of the valve can be changed to θ3 +,
It goes without saying that the same control as that of FIG. 7 of the first embodiment can be realized if the positions are 0 and θ3-.

Next, a fourth embodiment will be described. Fourth in FIG.
The figure explaining the schematic structure of the shock absorber 7B and the flow of hydraulic fluid in an Example is shown. In FIG. 24, the middle space of the cylinder 201 of the shock absorber 7B is the first space.
Similar to the embodiment, the main piston 202 divides the upper and lower parts into an upper liquid chamber 4a and a lower liquid chamber 4b, respectively. In the main piston 202, two expansion-side dedicated flow passages 22a and 22b and two contraction-side dedicated flow passages 21a and 21b penetrating the main piston 202 are formed in the outer peripheral portion. The plate check valve 208 provided and the plate check valve (not shown) provided on the upper surface close and open the valve.
The two dedicated channels have different channel cross-sectional areas, and when the hydraulic oil flows through the one with the larger channel cross-sectional area, it occurs than through the hydraulic oil with the smaller channel cross-sectional area. The damping force is smaller. For example, the extension-side dedicated channel 22a
In the case where the hydraulic oil circulates, the damping force generated becomes larger than that in the case where the hydraulic fluid 22b for the expansion side flows.

A control valve 200 is provided in the main piston 202. The control valve 200 is connected to an actuator (not shown), and is rotatable about the central axis of the main piston 202 when the actuator is driven.

A cross-sectional view of the control valve 200 cut in the CC direction is shown in FIG. The control valve 20 is provided with a crescent-shaped flow hole portion 300 that is capable of communicating and blocking the expansion-side dedicated flow path 22 and the contraction-side dedicated flow path 21 by rotating.

For example, in the state shown in FIG. 25, the working oil flows through the expansion-side dedicated flow path 22a and the contraction-side dedicated flow path 21a as shown in FIG. 24, and has a large damping force on both the expansion side and the contraction side. In the state shown in FIG. 26A, the hydraulic oil is
As shown in (b), it flows through the expansion-side dedicated flow path 22a and the contraction-side dedicated flow path 21b, and the expansion-side damping force is large and the contraction-side damping force is small. In the state shown in FIG. 27 (a), the hydraulic oil flows through the expansion-side dedicated flow path 22b and the contraction-side dedicated flow path 21a as shown in FIG. 27 (b), the expansion-side damping force is small, and the contraction-side damping force is growing. In the state shown in FIG. 28 (a), the hydraulic oil flows through the expansion-side dedicated flow path 22b and the contraction-side dedicated flow path 21b as shown in FIG. 28 (b), and both the expansion side and the contraction side have a small damping force.

With the above-described structure, the actuator is controlled so that the state shown in FIG.
By rotating the control valve 200 to the state shown in FIG. 8, it is possible to arbitrarily control the contraction side damping force while keeping the expansion side damping force small. Further, by rotating the control valve 200 from the state shown in FIG. 25 to the state shown in FIG. 26, it is possible to arbitrarily control the contraction-side damping force while keeping the expansion-side damping force large.

The operation of the damping force variable shock absorber having the above configuration will be described. In this embodiment as well, as in the first embodiment, the damping force is increased when the damping force of the shock absorber exerts a damping action on the vehicle body, and is reduced when the damping force acts on the vehicle body. To do so. Specifically, when the sprung speed is positive, the expansion side damping force of the shock absorber may be made large and the contraction side damping force may be made small. Therefore, as shown in FIG. The control valve 200 is rotated to a position where it flows only through the extension-side dedicated flow path 22a. Further, when the sprung speed is negative, the expansion side damping force of the shock absorber may be decreased and the contraction side damping force may be increased.
As shown in FIG. 7, the control valve 200 is rotated to a position where the operation flows only through the contraction-side dedicated flow passage 21a and the extension-side dedicated flow passage 22b.

Further, the control valve 200 may be rotated to the state shown in FIG. 25 or 28 depending on the running condition of the vehicle. The variable damping force shock absorber of the present invention is not limited to the above embodiment, and various modifications can be made, for example, as follows without departing from the spirit of the invention.

(1) A high-pass filter for extracting a frequency component higher than a predetermined value from the sprung resonance frequency in the sprung acceleration signal detected by the acceleration sensor 1 is provided, and when the output signal from the high-pass filter is a predetermined value or more, For example, control may be performed such that the valve rotation angle does not become θ3 + or θ3- (the damping force does not become high) and the transmission of high frequency vibration is suppressed. Further, for example, when the output signal from the high-pass filter is large, the absolute value of the switching threshold value may be increased according to the magnitude thereof, and the threshold value may be adjusted so that the damping force is hard to increase.

(2) A low-pass filter for extracting a component near the sprung resonance frequency in the sprung acceleration signal detected by the acceleration sensor 1 is provided, and according to the output signal from the low-pass filter, for example, as shown in (1) You may perform various controls.

(3) A high-pass filter for extracting a frequency component of the sprung mass acceleration signal detected by the acceleration sensor 1 that is higher than a sprung mass resonance frequency by a certain level and a low-pass filter for extracting a component near the sprung mass resonance frequency are provided. Depending on the ratio of the output signals from the two filters,
For example, control such as (1) may be performed.

(4) The control based on the sprung vertical direction speed signal may be performed instead of the control based on the vibration frequency. (5) The driver's favorite input device is not the two-step system described in the embodiment, but a system that allows continuous input, and is switched according to the value, for example, when the preference is hard. The threshold value may be adjusted so that the absolute value of the threshold value is reduced and the damping force is likely to increase.

(6) A state quantity such as a lateral acceleration of the vehicle body, a steering angular velocity, a vehicle speed, and the like, which indicates the turning state of the vehicle body, is detected. In the example, Vref1- to Vref3-) are increased so that the compression side damping force tends to increase, and the positive threshold value of the right wheel (Vref1 + to Vref3 + in the above embodiment) is decreased to increase the elongation. Control may be performed so that the side damping force easily increases and the vehicle body roll amount is suppressed.

(7) A state quantity such as the longitudinal acceleration of the vehicle body, the accelerator opening, the brake fluid pressure, etc., which indicates the acceleration / deceleration state of the vehicle body is detected. In the above-described embodiment, Vref1- to Vref3-) are increased so that the compression damping force is likely to increase, and the positive threshold value of the rear wheel (Vref1 + to Vre in the above-described embodiments).
f3 +) may be reduced so that the extension side damping force tends to increase, and control may be performed to suppress the vehicle body dive amount.

(8) The road surface condition may be estimated from the switching frequency of the actuators, and the magnitude of the damping force for damping the vehicle may be switched based on the estimated road surface condition. (9) The damping force shock absorber of the present invention may be controlled independently for each wheel, and it may be possible to control the absolute velocity on the spring and its threshold value according to the magnitude of the roll or pitch motion of the vehicle. Correction may be added to the signal processing in the comparison.

The absolute speed on the spring means the vertical absolute speed of the vehicle body near the suspension upper support of each wheel. Further, the relative speed between the sprung part and the unsprung part may be considered as the shock absorber expansion / contraction speed.

Generally, the damping force of the shock absorber depends on the expansion / contraction speed of the shock absorber, but in the present specification, "the damping force is increased", "the damping force is decreased", "the damping force is changed", etc. The expression of means changing the setting of the damping force in the control.

[0110]

As described in detail above, in the damping force variable shock absorber of the present invention, the flow of the other communication passage is kept constant while the flow passage area of one communication passage is kept constant by one movable portion of the valve means. Since the road area is changed, the damping force can be changed only in accordance with the change in the absolute speed on the spring to realize the characteristics close to those of the skyhook damper, and the extension side damping force and the contraction side damping force can be achieved with a simple device configuration. It has an excellent effect that it can be changed independently.

Further, in the variable damping force shock absorber control device of the present invention, the magnitude of the damping force for damping the movement of the vehicle body can be changed according to the running state of the vehicle. While achieving similar characteristics,
There is an excellent effect that the ride comfort can be secured and improved.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a first embodiment.

FIG. 2 is a cross-sectional view of a shock absorber 7.

FIG. 3 is a cross-sectional view of a shock absorber 7.

FIG. 4 is a cross-sectional view of a shock absorber 7.

FIG. 5 is a cross-sectional view of a shock absorber 7.

FIG. 6 is a cross-sectional view of a shock absorber 7.

FIG. 7 is a flowchart showing a process executed by the control unit 5.

FIG. 8 is a diagram showing the relationship between the absolute speed on the spring and the relative speed between the sprung part and the unsprung part in the first embodiment.

FIG. 9 is a cross-sectional view of a shock absorber 7A.

FIG. 10 is a cross-sectional view of a shock absorber 7A.

FIG. 11 is a relationship diagram between a rotation angle of a control valve and a communication area of a valve portion.

FIG. 12 is a transverse sectional view of a shock absorber 7A.

FIG. 13 is a cross-sectional view of a shock absorber 7A.

FIG. 14 is a transverse sectional view of a shock absorber 7A.

FIG. 15 is a cross-sectional view of a shock absorber 7A.

FIG. 16 is a flowchart showing processing executed by the control unit 5.

17 is a diagram showing signal processing in the flowchart of FIG.

FIG. 18 is a diagram showing the relationship between the absolute speed on the spring and the relative speed between the sprung part and the unsprung part in the second embodiment.

FIG. 19 is a block diagram showing the configuration of the third exemplary embodiment.

FIG. 20 is a flowchart showing a process executed by the control unit 5.

FIG. 21 is a flowchart showing a process executed by the control unit 5.

FIG. 22 is a flowchart showing a process executed by the control unit 5.

FIG. 23 is a diagram showing absolute velocity on the spring and damping force setting in the third embodiment.

FIG. 24 is an explanatory diagram of the fourth embodiment.

FIG. 25 is a sectional view of a shock absorber 7B.

FIG. 26 is an explanatory diagram of the fourth embodiment.

FIG. 27 is an explanatory diagram of the fourth embodiment.

FIG. 28 is an explanatory diagram of the fourth embodiment.

FIG. 29 is an explanatory diagram showing a Karnopp damping force control method.

FIG. 30 is a diagram showing the relationship between the absolute velocity on the spring and the relative velocity between the sprung member and the unsprung member and the damping force in the Karnopp control.

[Explanation of symbols]

 1 Acceleration Sensor 2 Integration Circuit 3 High Pass Filter 5 Control Unit 6 Actuator 7 Shock Absorber 8 Vehicle Speed Sensor 9 Favorite Input Device

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Kinji Hohei, 1-1, Showa-cho, Kariya city, Aichi prefecture

Claims (9)

[Claims] 1. A cylinder in which a working fluid is stored, a piston member which is slidably provided in the cylinder and divides the interior of the cylinder into an upper chamber and a lower chamber, and a cylinder member from the upper chamber to the lower chamber. A first communication passage that allows the working fluid to flow therethrough; a second communication passage that allows the working fluid to flow from the lower chamber to the upper chamber; and a first communication passage that adjusts the flow passage area of the first communication passage. A valve means for arranging the first hole and the second hole for adjusting the flow passage area of the second communication passage, and stopping at the first position, the second position, and the third position. Stop at the first position, the first hole has a small flow passage area of the first communication passage, and the second hole has a small flow passage area of the second communication passage. Is stopped at the second position, the first hole reduces the flow passage area of the first communication passage and increases the flow passage area of the second communication passage. A position, when the valve means is stopped in the third position, the first hole first
Of the first communication path and the second communication path of the second communication path are set so that the flow path area of the communication path is large and the second hole is small.
A shock absorber with variable damping force, characterized in that the holes are arranged. 2. A cylinder in which a working fluid is stored, a piston member which is slidably provided in the cylinder and divides the interior of the cylinder into an upper chamber and a lower chamber, and a piston member from the upper chamber to the lower chamber. A first communication passage that allows the working fluid to flow therethrough; a second communication passage that allows the working fluid to flow from the lower chamber to the upper chamber; and a first communication passage that adjusts the flow passage area of the first communication passage. A valve means for arranging the first hole and the second hole for adjusting the flow passage area of the second communication passage, and stopping at the first position, the second position, and the third position. Is stopped at the first position, the first hole has a large flow passage area of the first communication passage, and the second hole has a large flow passage area of the second communication passage. Is stopped at the second position, the first hole reduces the flow passage area of the first communication passage and increases the flow passage area of the second communication passage. A position, when the valve means is stopped in the third position, the first hole first
Of the first communication path and the second communication path of the second communication path are set so that the flow path area of the communication path is large and the second hole is small.
A shock absorber with variable damping force, characterized in that the holes are arranged. 3. The valve means stops in a fourth position,
When the valve means is stopped at the fourth position, the first hole has a large flow passage area of the first communication passage, and the second hole has a position having a medium flow passage area of the second communication passage. The first hole and the second hole are arranged so that
Alternatively, the damping force variable shock absorber described in 2. 4. The valve means stops in a fifth position,
When the valve means is stopped at the fifth position, the first hole is located at a position where the flow passage area of the first communication passage is medium and the second hole is at a position where the flow passage area of the second communication passage is increased. The first hole and the second hole are arranged so that
4. A variable damping force shock absorber according to any one of 3 to 3. 5. The valve means stops at a sixth position,
When the valve means is stopped at the sixth position, the first hole has a small flow passage area of the first communication passage, and the second hole has a middle position of the flow passage area of the second communication passage. The first hole and the second hole are arranged so that
5. A variable damping force shock absorber according to any one of 4 to 4. 6. The valve means stops in a seventh position,
When the valve means is stopped at the seventh position, the first hole is at a position where the flow passage area of the first communication passage is medium and the second hole is at a position where the flow passage area of the second communication passage is small. The first hole and the second hole are arranged so that
6. A variable damping force shock absorber according to any one of 5 to 5. 7. A speed calculating means for calculating a vertical speed on a spring, a running state detecting means for detecting a running state of a vehicle, a cylinder in which a working fluid is stored, and a slidable inside the cylinder. A piston member that divides the interior of the cylinder into an upper chamber and a lower chamber; a first communication passage that allows the working fluid to flow from the upper chamber to the lower chamber; and a lower communication chamber from the lower chamber to the upper chamber. A second communication passage that allows the working fluid to flow, a first hole that adjusts the flow passage area of the first communication passage, and a second hole that adjusts the flow passage area of the second communication passage are arranged. , Valve means for stopping at the first position, the second position, and the third position, and when the valve means stops at the first position, the first hole has the first position.
Of the communication passage is small, the second hole is at a position where the flow passage area of the second communication passage is small, and when the valve means is stopped at the second position, the first hole is the first hole. The flow passage area of the communication passage is small,
The second hole is at a position where the flow passage area of the second communication passage is large,
When the valve means is stopped at the third position, the first hole is at a position where the flow passage area of the first communication passage is large and the second hole is at a position where the flow passage area of the second communication passage is small. A damping force variable shock absorber characterized in that the first hole and the second hole are arranged so that the value of the vertical velocity on the spring calculated by the velocity calculating means and the traveling state. A damping force variable shock absorber control device comprising: a changing unit that operates the valve unit according to a traveling state of the vehicle detected by the detecting unit. 8. A speed calculation means for calculating a vertical speed on a spring, a cylinder in which a working fluid is stored, and a slidably provided inside the cylinder, and the inside of the cylinder is divided into an upper chamber and a lower chamber. A piston member, a first communication passage that allows the working fluid to flow from the upper chamber to the lower chamber, and a second communication passage that allows the working fluid to flow from the lower chamber to the upper chamber.
Of the first communication passage, the first hole for adjusting the flow passage area of the first communication passage, and the second hole for adjusting the flow passage area of the second communication passage are arranged at the first position, the second position Position, and valve means for stopping at the third position, and when the valve means stops at the first position, the first hole has a large flow passage area of the first communication passage, and the second hole has The first hole is at the first position when the valve means is stopped at the second position at a position where the flow passage area of the second communication passage is large.
When the valve means is stopped at a position where the flow passage area of the communication passage is small, the second hole is at a position where the flow passage area of the second communication passage is large, and the valve means is stopped at the third position, the first hole is The first hole and the second hole are arranged such that the flow passage area of the first communication passage is large and the second hole is at a position where the flow passage area of the second communication passage is small. A damping force variable shock absorber characterized by: and a changing means for operating the valve means according to a value of a vertical velocity on a spring calculated by the velocity calculating means, Variable shock absorber control device. 9. A traveling state detecting means for detecting a traveling state of the vehicle, wherein the changing means is detected by the traveling state detecting means and the value of the vertical speed on the spring calculated by the speed calculating means. 9. The damping force variable shock absorber control device according to claim 8, wherein the valve means is operated according to a running state of the vehicle.