JPH10318323A - Suspension device and control method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the steering stability of a vehicle yet higher than ever before as making improvements in riding quality in time of vehicle running. SOLUTION: This device is so constituted that a rebound spring displaying its resistance force to the extension motion of a shock absorber 2 is installed in this shock absorber 2 being installed in a space between a support member 6 supporting a wheel W and a car body 4. In this case, a spring characteristic in the rebound spring is preconstituted to be variably controllable from the outside of the shock absorber 2, and in time of vehicle running, the spring characteristic in the rebound spring is varied according to the running conditions. With this constitution, a resistance characteristic in the shock absorber 2 at a time when the wheel W rebounds, is thus varied.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a suspension device control method and a suspension device.

[0002]

2. Description of the Related Art Conventionally, an example of a suspension device is disclosed in Japanese Patent Application Laid-Open No. 60-45411. In the suspension device described in the publication, a fluid pressure chamber is formed in a suspension bush for upper support of a shock absorber mounted between a support member for supporting wheels and a vehicle body. According to such a configuration, by allowing oil pressure to flow into and out of the fluid pressure chamber, the spring constant of the suspension bush for upper support can be changed according to running conditions.

As another example of a conventional suspension device, Japanese Utility Model Laid-Open No. 3-43140 and Japanese Utility Model Laid-Open No.
There is one described in 106536. In the suspension devices described in these publications, a rebound spring is provided inside a shock absorber mounted between a support member for supporting wheels and a vehicle body. According to such a configuration, when the piston rod of the shock absorber is extended during the rebound of the wheel, the rebound spring exerts a resistance to the operation thereof, and it is possible to prevent the vehicle body from lifting.

[0004]

However, in the above-mentioned conventional suspension device, the following problems have occurred.

That is, in the above-mentioned conventional suspension device, when the spring constant of the suspension bush for the upper support of the shock absorber is changed, the spring constant of the entire suspension device changes accordingly. Therefore, during turning of the vehicle, when the spring constant of the bush is increased in order to increase the roll rigidity and the vehicle approaches a rough road, the spring constant of the entire suspension apparatus is high, and The grounding of the vehicle deteriorates, and the riding comfort of the vehicle deteriorates. in this way,
In the above-mentioned conventional suspension device, after all, only the spring constant of the suspension device as a whole can be increased or decreased, so that the vehicle stability is improved without adversely affecting the riding comfort of the vehicle. Had become difficult. Furthermore, in order for oil to flow into and out of the fluid pressure chamber of the upper support suspension bush, it is necessary to constantly drive a dedicated oil pump, and the energy loss has been increased.

On the other hand, in the above-mentioned conventional suspension device, the rebound spring exerts a resistance when the wheel rebounds and the shock absorber expands. No resistance to movement. Therefore, with this suspension device, it is possible to increase the roll rigidity only on the rebound side, and unlike the above-mentioned conventional one, it is possible to enhance the vehicle's steerability without affecting the vehicle's ride comfort. Becomes However, in the latter conventional suspension device, the rebound spring is simply housed in the cylinder of the shock absorber. In the suspension device described in Japanese Utility Model Laid-Open No. 4-106536, a plurality of rebound springs having different spring constants are used, but these rebound springs are merely arranged in parallel in the shock absorber. In such a configuration, the rebound spring always exerts only the resilience corresponding to the amount of extension of the shock absorber in response to the extension of the shock absorber. Therefore, in the latter conventional suspension device, the resistance characteristics of the shock absorber cannot be appropriately changed according to the actual running conditions of the vehicle. There was room to be.

The present invention was conceived in view of such circumstances, and is intended to improve the ride comfort of a vehicle and to further enhance the stability of the vehicle than before. Is the task.

[0008]

DISCLOSURE OF THE INVENTION In order to solve the above problems, the present invention employs the following technical means.

According to a first aspect of the present invention, there is provided a control method of a suspension device. The control method of this suspension device includes a shock absorber installed between a support member supporting the wheels and a vehicle body,
A method of controlling a suspension device provided with a rebound spring exhibiting a resistance to an extension operation of the shock absorber, wherein a spring characteristic of the rebound spring is configured to be variably controllable from outside the shock absorber, and By changing the spring characteristics of the rebound spring during running according to the running conditions, the resistance characteristics of the shock absorber when the wheel rebounds are changed.

According to a second aspect of the present invention, there is provided a suspension device. This suspension device
A shock absorber mounted between a support member supporting a wheel and a vehicle body, a suspension device provided with a rebound spring exhibiting a resistance to an extension operation of the shock absorber,
The shock absorber is characterized by having a spring characteristic changing mechanism capable of changing the spring characteristic of the rebound spring from outside the shock absorber.

[0011] The present invention has a novel structure in which the spring characteristics of the rebound spring provided inside the shock absorber are variably controlled from the outside, which has never been seen before, and the following effects are obtained. Can be That is,
According to the present invention, by changing the spring characteristics of the rebound spring according to the vehicle traveling conditions, it is possible to variously change the resistance characteristics of the shock absorber when the wheel rebounds. For example, when the vehicle enters a high-G limit region during or near a high-speed turn of the vehicle, by setting the resistance characteristics of the shock absorber to hard, the roll rigidity of the suspension is increased to suppress the vehicle behavior, The vehicle operability can be improved. Of course, during a normal vehicle running that does not reach the high G limit region, the resistance characteristics of the shock absorber according to the running conditions can be selected. On the other hand, by controlling the spring characteristics of the rebound spring and changing the resistance characteristics of the shock absorber, it is possible to prevent the vehicle body from floating on the rebound side of the wheels. The posture matches the occupant's bodily sensation, and the riding comfort is also good. Moreover, the effect of preventing the vehicle body from being lifted can be controlled by changing the spring characteristics of the rebound spring so as to minimize discomfort to the occupant. Therefore, according to the invention of the present application, there is obtained an effect that it is possible to improve the riding comfort of the vehicle and improve the operability of the vehicle as compared with the conventional case.

According to a third aspect of the present invention, there is provided a suspension device. This suspension device
A rebound spring is provided inside a shock absorber attached between the support member supporting the wheels and the vehicle body, and when the piston rod of the shock absorber is extended, the upper end of the rebound spring is connected to the shock absorber. A suspension device configured to be compressed by contacting an inner upper wall portion, wherein said shock absorber is provided inside said shock absorber by operation of a predetermined driving means provided outside said shock absorber. A movable member reciprocally movable in the axial direction of the absorber is provided, and the movable member includes:
It is characterized by having a supporting portion for supporting the lower end of the rebound spring so that the height of the lower end of the rebound spring is changed by the reciprocation of the movable member.

[0013] Preferably, the piston rod of the shock absorber is formed in a hollow shape, and the movable member is housed therein. According to such a configuration, the piston rod of the shock absorber can be effectively used as a guide member of the movable member. For example, a dedicated member for supporting the movable member and guiding its reciprocating operation is provided by the shock absorber. There is no need to separately provide the inside, which is advantageous in simplifying the entire structure.

According to the present invention, the movable member is moved in the axial direction of the shock absorber by operating the driving means provided outside the shock absorber, so that the rebound supported by the supporting portion of the movable member. Since the height of the lower end of the spring can be changed, the following effects can be obtained. That is, when the movable member is lowered, the height of the entire rebound spring can be reduced.For example, in a normal state where the wheels are not bound or rebound, the upper end of the rebound spring and the inside of the shock absorber are A gap can be provided between the upper wall portion. In the setting state where the gap is provided in this manner, even if the wheel rebounds and the piston rod of the shock absorber starts to extend, the upper end of the rebound spring is immediately pressed by the upper wall of the shock absorber. Therefore, the compression start timing of the rebound spring can be delayed. In addition, when the compression start time of the rebound spring is delayed in this way, the compression amount of the rebound spring at the time of rebound of the wheel can be reduced by that amount, and the resistance of the rebound spring to the elongation operation of the piston rod can be reduced. Is also possible. On the other hand, when the movable member is raised, the height of the entire rebound spring is increased, for example, in a normal state where the wheels are not bound or rebound, the upper end of the rebound spring and the upper part of the inside of the shock absorber are used. It can be set in a state where no gap is provided between the wall portion. With this setting,
When the wheel rebounds and the shock absorber starts to extend, the rebound spring can be compressed immediately, and the compression start time of the rebound spring can be advanced. Further, when the compression start time of the rebound spring is advanced, the amount of compression of the rebound spring at the time of rebound of the wheel can be increased by that amount, and the resistance of the rebound spring to the extension operation of the piston rod can be increased. As described above, in the suspension device provided by the third aspect of the present invention, it is possible to variably control when the rebound spring exerts a resistance when the wheel rebounds and the magnitude of the resistance.
Therefore, it is useful to carry out the control method of the suspension device provided by the first aspect of the present invention.

Further, in the suspension device provided by the third aspect of the present invention, the spring characteristics of the rebound spring can be controlled continuously and steplessly. It becomes more preferable. Further, since the compression amount of the rebound spring is changed by moving the movable member forward and backward in the longitudinal direction of the shock absorber, for example, a motor or the like is used as a driving unit for reciprocating the movable member. Can be. Therefore,
It is possible to eliminate waste such as constantly driving a pressure drive source such as an oil pump.

According to a fourth aspect of the present invention, there is provided a suspension device. This suspension device
A suspension device in which a rebound spring that is compressed when a piston rod of the shock absorber is extended is provided inside a shock absorber attached between a support member supporting a wheel and a vehicle body, wherein the rebound spring is provided. The spring includes a bellows, and the bellows is externally fitted to a hollow member having an opening through which the fluid sealed inside the shock absorber can flow into and out of the bellows, and It is characterized in that a valve element is provided inside the hollow member for opening and closing an opening of the hollow member by the operation of a predetermined driving means provided outside the shock absorber.

Preferably, the piston rod of the shock absorber is formed in a hollow shape, and the piston rod is the hollow member. According to such a configuration, the piston rod of the shock absorber can be effectively used as a hollow member for accommodating the valve body, so that a dedicated hollow member for accommodating the valve body is provided inside the shock absorber. There is no need to provide them separately, which is advantageous in simplifying the entire structure.

In the present invention, when the drive means provided outside the shock absorber is operated to operate the valve body, the opening of the predetermined hollow member is opened and closed, and the valve is sealed inside the shock absorber. Fluid can flow into and out of the bellows. That is, the state can be switched between a state in which the fluid is sealed in the bellows and a state in which the fluid is not sealed. On the other hand, the rebound spring is provided with the above-mentioned bellows, and the entire spring constant differs between when the fluid is sealed inside the bellows and when it is not sealed. Therefore,
By controlling the operation of the valve body from the outside of the shock absorber and switching between the state in which the fluid is sealed in the bellows and the state in which the fluid is not sealed, the resistance characteristics of the shock absorber can be changed. Thus, the method of controlling a suspension device provided by the first aspect of the present invention can be suitably implemented.
Further, the spring constant of the rebound spring can be changed without changing the timing at which the rebound spring is compressed. Further, as a means for operating the valve body, a motor or the like can also be used,
It is possible to eliminate waste such as constantly driving a pressure drive source such as an oil pump.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be specifically described below with reference to the drawings.

FIG. 1 is a sectional view of an essential part showing an example of a suspension device S according to the present invention. FIG. 2 is a cross-sectional view of a main part showing an example of a state in which the suspension device S shown in FIG. 1 is operated. FIG. 3 is an explanatory diagram showing a control system of a vehicle using the suspension device S shown in FIG. FIG.
FIG. 3 is an explanatory diagram showing spring characteristics of the suspension device S shown in FIG.

In FIG. 1, the suspension device S
Comprises a main spring 1, a shock absorber 2, a rebound spring 3, and members or parts described below that constitute a spring characteristic changing mechanism that makes the spring characteristics of the rebound spring 3 variable.

The main spring 1 includes an upper bracket 99 attached to the vehicle body 4 and a cylinder 20 of the shock absorber 2.
It is sandwiched and attached between a lower bracket 98 attached to the outer periphery of the lower part. Above shock absorber 2
The lower part of the cylinder 20 is connected to the support member 6 that supports the wheel W (see FIG. 3). The upper end of the piston rod 21 is fixedly attached to the vehicle body 4 via a bush 97 and a nut 96. The rebound spring 3 is a compression coil spring, and is disposed above the piston 22 in the cylinder 20.

The whole or a part of the piston rod 21 is formed in a hollow shape (pipe shape), and a movable rod 50 is arranged inside the piston rod 21. A cable 53 is connected to the upper part of the movable rod 50, and the cable 53 is connected to the piston rod 2 via a guide tube 54 connected to the upper end of the piston rod 21.
1 has been pulled out. As shown in FIG. 3, the cable 53 drawn out of the piston rod 21
Is wound around a drum 55 that can be driven and rotated by a motor M. Therefore, when the motor M is driven to rotate the drum 55 forward or backward, the cable 53 is wound around the drum 55 or unwound from the drum 55. The movable rod 50
Reciprocates vertically within the piston rod 21 by such a winding operation and an unwinding operation of the cable 53.

Above the piston 22, a hollow disk-shaped movable plate 51 for supporting the lower end 3b of the rebound spring 3 is arranged. The movable plate 51 is connected to a lower end of the movable rod 50 via a stay 52. Therefore, the movable plate 51 moves up and down with the movement of the movable rod 50 up and down. The upper surface of the movable plate 51 is a portion corresponding to an example of a support portion of the movable member according to the present invention. As shown in FIG.
When the rebound spring 3 is lowered, the entire rebound spring 3 can be disposed at a relatively low position, and an appropriate gap h is formed between the upper end portion 3a of the rebound spring 3 and the upper wall portion 26 in the cylinder 20. Can be done. On the other hand, as shown in FIG. 2, when the movable plate 51 is raised, the entire height of the rebound spring 3 can be raised. For example, the upper end 3a of the rebound spring 3 and the upper wall 26 A gap can be prevented from being generated between them. In this embodiment,
Although the rebound spring 3 is merely placed on the upper surface of the movable plate 51, the present invention is not limited to this.
The lower end 3b of the rebound spring 3 and the movable plate 51 may be connected.

An elongate hole 27 is provided in the peripheral wall of the piston rod 21 to allow the stay 52 to move up and down with the up and down operation of the movable rod 50.
The stay 52 is movable along 7. One or more seal members 95 are provided between the outer peripheral surface of the movable rod 50 and the inner peripheral surface of the piston rod 21. The sealing member 95 serves to prevent oil sealed in the cylinder 20 from flowing into the piston rod 21 through the long hole 27 and prevent the oil from leaking above the piston rod 21.

In the configuration shown in FIG. 3, the suspension device S includes front wheels Wf, Wf and rear wheels Wr, Wf of the vehicle.
r is used as a suspension device for suspending the vehicle. However, the present invention is not limited to this. For example, only the front wheels Wf, Wf of the vehicle may be suspended by the suspension device S, and the rear wheels Wr, Wr may be applied with a suspension device having another configuration. The devices for controlling the suspension device S receive signal inputs from a lateral G sensor 8a, a steering wheel angle sensor 8b, a vehicle speed sensor (vehicle speed sensor of four wheels) 8c, and various other sensors (not shown). There is a controller 7. The controller 7 controls the rotation angles of the drive shafts of the two motors M, M via a power supply 70 connected to a power supply 71. Consequently, the spring characteristics of the rebound spring 3 are controlled by the controller 7. The controller 7 stores, for example, data of a model for estimating the motion state of the vehicle, and compares the data with data input from the above various sensors so that the yaw rate of the vehicle becomes a target value. M, M are controlled to change the spring characteristics of the rebound spring 3 by driving M.

In the suspension device S, as shown in FIG. 2, the movable rod 50 and the movable plate 51 are in the raised position, and the movable rod 50 and the movable plate 51 are located between the upper end 3a of the rebound spring 3 and the upper wall 26 in the cylinder 20. When there is no gap, the spring characteristic of the suspension device S is the spring characteristic of the broken line a shown by the solid line in FIG. That is, when the wheel bounces, the rebound spring 3 is not compressed. Therefore, in the region A of FIG. 4 corresponding to the bound region, the spring constant of the suspension device S is the spring constant of the main spring 1. On the other hand, in the setting state shown in FIG. 2, when the wheels rebound, the cylinder 20 of the shock absorber 2 descends relative to the vehicle body 4, so that the upper end 3 a of the rebound spring 3 is attached to the upper wall of the cylinder 20. The rebound spring 3 is immediately pressed downward by the portion 26, and the rebound spring 3 is compressed between the upper wall portion 26 and the movable plate 51. Therefore, in the region B of FIG. 4 corresponding to the rebound region, the spring constant of the suspension device S is
The spring constant is the sum of the main spring 1 and the rebound spring 3.

On the other hand, as shown in FIG.
And the movable plate 51 is lowered, and the rebound spring 3
When the gap h is provided between the upper end portion 3a of the cylinder 20 and the upper wall portion 26 in the cylinder 20, the spring characteristic of the broken line b shown by the broken line in FIG. 4 is obtained at the time of rebound. That is, since the gap h exists above the rebound spring 3, even if the wheel rebounds, the upper end portion 3a of the rebound spring 3 is not immediately pressed by the upper wall portion 26. For a while, the state where the rebound spring 3 is not compressed is maintained. Therefore, in the certain range B 'at the beginning of the rebound start shown in FIG. 4, the resistance of the rebound spring 3 is not exhibited, and the spring constant of the main spring 1 alone is obtained. However, when the rebound stroke of the wheel increases, the upper wall 26 comes into contact with the upper end 3a of the rebound spring 3, and the rebound spring 3 is compressed between the upper wall 26 and the movable plate 51. Thus, the rebound spring 3 and the main spring 1 have a combined spring characteristic.

As described above, in the suspension device S, the movable rod 50 and the movable plate 51 are moved up and down to change the height of the rebound spring 3, thereby starting the compression of the rebound spring 3 when the shock absorber 2 is extended. The timing can be different. That is, the resistance characteristics when the shock absorber 2 extends can be made non-linear.

Further, if the compression start timing of the rebound spring 3 is made different as described above, even if the rebound stroke of the wheel is the same, the rebound spring 3
Are different from each other, and the resistance (resilient force) of the rebound spring 3 can also be changed. Specifically, as shown in FIG. 2, when the rebound spring 3 is compressed almost at the same time as the start of the rebound, the rebound spring 3 has substantially the same size as the relative descending dimension of the cylinder 20 with respect to the vehicle body 4. Therefore, the amount of compression of the rebound spring 3 can be increased, and its resistance can be increased. However,
As shown in FIG. 1, when a gap h is provided above the rebound spring 3 so that the rebound spring 3 is not compressed at the beginning of the rebound, the compression amount of the rebound spring 3 is different from that in FIG. 2. In comparison, the gap h is smaller, and the resistance of the rebound spring 3 is smaller by that amount. Therefore, in the suspension device S, the magnitude of the resistance force when the shock absorber 2 extends can be increased or decreased. Further, the height of the rebound spring 3 can be changed steplessly by moving the movable plate 51 up and down. Therefore, in the suspension device S, the spring characteristics can be freely selected and set in the range C between the broken lines a and b of the two spring characteristics shown in FIG.

In the suspension device S, for example, the following control is performed when the vehicle is running. First, during normal running of the vehicle, as shown in FIG. 1, the movable rod 50 and the movable plate 51 are lowered, and a set state is established in which a gap h is provided above the upper end 3 a of the rebound spring 3. In such a state, the rebound spring 3 is not compressed even if the shock absorber 2 is slightly extended, and the resistance characteristic of the shock absorber 2 can be made soft. Next, when the vehicle turns at a high speed and a very large lateral G is generated, the cable 53 is wound in the direction in which the movable rod 50 and the movable plate 51 rise under the control of the controller 7, and the lower end 3b of the rebound spring 3 is Increase the height. By doing so, the resistance of the rebound spring 3 can be exhibited by bringing the upper end 3a of the rebound spring 3 into contact with the upper wall portion 26 in the cylinder 20, and the roll rigidity of the vehicle can be increased. . Therefore, it is possible to prevent the vehicle body from floating on the rebound side of the wheel. In addition, by increasing the roll rigidity in this way, it is possible to control the vehicle behavior to bring the value of the yaw rate of the vehicle closer to the target yaw rate, thereby improving the operability of the vehicle. As described above, in the suspension device S, the spring characteristics at the time of rebound of the suspension device S are changed within the range indicated by reference numeral C in FIG. Characteristics and resistance characteristics can be selected. Therefore, the operability of the vehicle can be remarkably improved as compared with the conventional one in which the spring characteristics of the rebound spring are constant.

FIG. 5 is a cross-sectional view of a main part showing another example of the suspension device Sa according to the present invention. FIG. 6 is a sectional view of a main part showing the operation state. In these drawings, the same parts as those in the previous embodiment are denoted by the same reference numerals.

The suspension device Sa does not use a compression coil spring as the rebound spring 3A. The rebound spring 3A is composed of two rubbers 33, 33a as elastic members and these rubbers 33, 33.
and a bellows 34 provided between them. Of course, in the present invention, the above two rubbers 3
Instead of 3, 33a, one or more coil springs can be used. The rebound spring 3A is connected to the piston rod 21 of the shock absorber 2A.
A, and the piston 22
It is attached to the upper surface part of.

The piston rod 21A is formed in a hollow shape (pipe shape). The first opening 28 communicating with the inside of the bellows 34 and the opening 90a of the auxiliary member 90 are formed in the peripheral wall. And a second opening 29 that communicates with the oil storage portion in the cylinder 20 through the second opening 29. A rod-shaped valve body 56 is provided inside the piston rod 21A. The valve body 56 has a flow passage 57 that connects the first opening 28 and the second opening 29 to each other. Therefore, as shown in FIG. 5, the first opening 28 and the second opening 29
Are communicated with each other via the flow passage 57, the oil in the cylinder 20 can flow into and out of the bellows 34 through the communication passage 57. The upper portion 56a of the valve body 56 projects above the upper end of the piston rod 21A. Upper part 5 of this valve body 56
Reference numeral 6a is connected to, for example, a drive shaft of a step motor (not shown). When the step motor is driven, the valve body 56 is configured to rotate in the circumferential direction inside the piston rod 21A. ing.
As shown in FIG. 6, when the valve body 56 is rotated so that the flow passage 57 does not allow the first opening 28 and the second opening 29 to communicate with each other, the bellows 34
Is filled with oil. An auxiliary spring 91 is provided inside the bellows 34. The auxiliary spring 91 exerts a resilient force in the direction of separating the two rubbers 33 and 33a from each other. The bellows 34 is constantly subjected to a force that extends in the vertical direction by the auxiliary spring 91 and is compressed by the piston 22. Will have a restoring force after the

In the suspension device Sa having the above configuration, when the valve body 56 is set to the state shown in FIG. 5, the resistance characteristics when the shock absorber 2A extends can be set softly. That is, when the shock absorber 2A extends in the above-described setting state, the piston 22 presses the rebound spring 3A upward. At this time, the oil flowing into the bellows 34 causes the first opening 28, It flows out to the other part in the cylinder 20 through the flow passage 57 and the second opening 29. Therefore, in this case, the bellows 34
Gradually exerts a resistance to the piston 22 when the compression is gradually changed, and the elastic force of the two rubbers 33, 33a also acts as a resistance to the piston 22. In this case, the spring characteristics of the entire suspension device Sa are more specifically in the state of the broken line c shown by the solid line in FIG.
The spring characteristic indicated by the polygonal line c indicates the bounding area A of the wheel.
Is the spring constant of the main spring 1. However, in the constant area Ba at the beginning of the rebound start of the wheel, the spring constant takes into account the resistance force when the bellows 34 is compressed and deformed. Then, in the region Bb after the completion of the compression deformation of the bellows 34, the rubbers 33, 33a are compressed and deformed, and the spring constant of the rubbers 33, 33a and the spring constant of the main spring 1 become a combined spring constant. .

On the other hand, as shown in FIG.
Is rotated to keep the inside of the bellows 34 in a closed state, so that the bellows 34 is prevented from being compressed and deformed when the bellows 34 receives a compressive force by the piston 22. In this case, the spring characteristic of the entire suspension device Sa is more specifically a broken line d shown by a broken line in FIG. The spring characteristic indicated by the broken line d is due to the fact that the bellows 34 is not compressed and deformed, and the spring constant of the main spring 1 and the spring constants of the rubbers 33 and 33a are matched in the entire rebound region B of the wheel. It becomes a constant.

As described above, the suspension device Sa
In, the spring constant of the entire rebound spring 3A can be switched in two ways by rotating the valve body 56. In addition, the timing at which the rebound spring 3A starts compression when the wheel rebounds can be set to be substantially the same in any of the settings shown in FIGS. Therefore, in this suspension device Sa, it is possible to change only the spring constant of the rebound spring 3A without changing the timing at which the rebound spring 3A exerts the resistance to the extension operation of the shock absorber 2A.

In the suspension device Sa, the spring constant of the rebound spring 3A is lowered during normal running, and the resistance characteristics of the shock absorber 2A are set softly. By increasing the spring constant of the shock absorber 3A and setting the resistance characteristics of the shock absorber 2A to be hard, a comfortable ride and excellent maneuverability can be obtained. The controller for controlling the rotation of the valve body 56 may have the same configuration as the controller 7 shown in FIG.

The specific configuration of the control method of the suspension device according to the present invention is not limited to the above embodiment. Similarly, the specific configuration of each part of the suspension device according to the present invention can be variously changed in design. As a spring characteristic changing mechanism for variably controlling the spring characteristic of the rebound spring of the shock absorber from the outside, a mechanism having a configuration different from the above-described mechanism can be adopted.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part showing an example of a suspension device according to the present invention.

FIG. 2 is a cross-sectional view of a main part showing an example of a state in which the suspension device shown in FIG. 1 is operated.

FIG. 3 is an explanatory diagram showing a control system of a vehicle using the suspension device shown in FIG. 1;

FIG. 4 is an explanatory diagram showing spring characteristics of the suspension device shown in FIG.

FIG. 5 is a sectional view of a main part showing another example of the suspension device according to the present invention.

6 is a cross-sectional view of a main part showing an operation state of the suspension device shown in FIG.

FIG. 7 is an explanatory diagram showing spring characteristics of the suspension device shown in FIG.

[Explanation of symbols]

 S, Sa Suspension device 2, 2A Shock absorber 3, 3A Rebound spring 4 Body 6 Support member 20 Cylinder 21, 21A Piston rod 22 Piston 26 Upper wall 28 First opening 29 Second opening 33 Rubber 34 Bellows 50 Movable rod (movable member) 51 Movable plate (movable member) 53 Cable 55 Drum 56 Valve M Motor W Wheel

Claims (4)

[Claims] 1. A method of controlling a suspension device in which a rebound spring is provided inside a shock absorber mounted between a support member supporting a wheel and a vehicle body, the rebound spring exerting a resistance to the extension operation of the shock absorber. The spring characteristics of the rebound spring are configured to be variably controllable from the outside of the shock absorber, and the wheels are changed by changing the spring characteristics of the rebound spring in accordance with the traveling conditions when the vehicle travels. A method of controlling a suspension device, characterized by changing a resistance characteristic of the shock absorber when rebounding. 2. A suspension device in which a rebound spring is provided inside a shock absorber mounted between a support member supporting a wheel and a vehicle body, the rebound spring exerting a resistance to the extension operation of the shock absorber. A suspension device comprising a spring characteristic changing mechanism capable of changing a spring characteristic of the rebound spring from outside the shock absorber. 3. A rebound spring is provided inside a shock absorber mounted between a support member supporting a wheel and a vehicle body, and an upper end of the rebound spring when a piston rod of the shock absorber extends. Is a suspension device configured to abut against an upper wall portion of the inside of the shock absorber, and is provided inside the shock absorber with a predetermined driving means provided outside the shock absorber. The movable member is provided so as to be reciprocable in the axial direction of the shock absorber by the operation of, and the height of the lower end of the rebound spring is changed by the reciprocating movement of the movable member. Having a supporting portion for supporting the lower end of the rebound spring. The butterfly, the suspension device. 4. A suspension device in which a rebound spring which is compressed when a piston rod of the shock absorber is extended is provided inside a shock absorber mounted between a support member supporting a wheel and a vehicle body. The rebound spring includes a bellows, and the bellows is fitted to a hollow member having an opening through which the fluid sealed in the shock absorber can flow into and out of the bellows. And a valve body that opens and closes an opening of the hollow member by operation of a predetermined driving means provided outside the shock absorber is provided inside the hollow member. Suspension device.