Suspension system and rear cushion unit

Abstract

To provide a suspension system which enables improvement of riding quality in a vehicle, and to provide a rear cushion unit.SOLUTION: A suspension system S according to the present invention includes: a suspension spring 30 that supports a vehicle body F of a vehicle M; a movable spring seat 31 that supports one end of the suspension spring 30 and may be displaceable in a direction in which the suspension spring 30 expands or contracts; a housing 32 that forms a pressure chamber P which houses a liquid between the housing 32 and the movable spring seat 31 while allowing for movement of the movable spring seat 31 in the direction in which the suspension spring 30 expands or contracts; a stopper 33 that, when the pressure chamber P is maximized by the movable spring seat 31 moving toward the suspension spring side relative to the housing 32, prevents further movement of the movable spring seat 31 toward the suspension spring side; and elastic pressurization means 34 that can pressurize the inside of the pressure chamber P with elastic force and can adjust the elastic force.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a suspension device and a reaction unit.

Background Art

[0002] A suspension device forms a reaction unit together with a shock absorber body and is used, for example, by being interposed between the vehicle body and the rear wheels of a saddle-riding type vehicle to elastically support the vehicle body.

[0003] Further, the reaction unit includes, for example, a cylinder, a piston that is movably inserted into the cylinder and divides the inside of the cylinder into an extension chamber and a compression chamber filled with hydraulic oil, and a rod that is movably inserted into the cylinder and connected to the piston. And a suspension spring interposed between a spring seat attached to the outer periphery of the cylinder and a spring seat attached to the outer periphery of the tip of the rod. The reaction unit configured in this way elastically supports the vehicle body with the suspension spring when interposed between the vehicle body and the rear wheels, and the shock absorber body generates a damping force for the vertical relative movement between the vehicle body and the rear wheels. Can suppress the vibration of the vehicle body and the rear wheels (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Conventional suspension devices can adjust the vehicle height by changing the support position of the suspension spring on the spring seat on the cylinder side, but since the spring constant of the suspension spring cannot be changed, there is room for improvement in the ride comfort of the vehicle.

[0006] Therefore, the present invention aims to provide a suspension system and a rear cushion unit that can improve ride comfort in a vehicle. [Means for solving the problem]

[0007] To solve the aforementioned problems, the suspension device of the present invention comprises a suspension spring that supports the body of a vehicle, a movable spring support that supports one end of the suspension spring and is displaceable in the direction of expansion and contraction of the suspension spring, a housing that allows the movable spring support to move in the direction of expansion and contraction of the suspension spring and forms a pressure chamber between itself and the movable spring support for containing liquid, a stopper that prevents the movable spring support from moving further toward the suspension spring when the movable spring support moves toward the suspension spring side relative to the housing to maximize the pressure chamber, and an elastic pressurizing means that can pressurize the inside of the pressure chamber by elastic force and can adjust the elastic force.

[0008] In this suspension system, the elastic pressurizing means pressurizes the pressure chamber by elastic force, and one end of the suspension spring is supported by a movable spring support. Therefore, by adjusting the pressure that the elastic pressurizing means applies to the pressure chamber, the movable spring support can be fixed immovably in a position restricted by the stopper, and the movable spring support can be displaced relative to the housing according to the degree of compression of the suspension spring. Furthermore, because the elastic pressurizing means pressurizes the pressure chamber with elastic force, when the movable spring support is displaced relative to the housing, it receives the elastic force of the elastic pressurizing means and functions as a spring together with the suspension spring, thus reducing the spring constant in the suspension system.

[0009] Furthermore, the elastic pressurizing means in the suspension device may include a container, a movable bulkhead that is movably inserted into the container and partitions a space within the container that communicates with a pressure chamber, and a gas and a liquid contained within the container. With a suspension device configured in this way, the elastic pressurizing means functions as an air spring and can adjust the degree of compression of the gas by the displacement of the movable bulkhead within the container, thereby adjusting the elastic force acting in the pressure chamber. Therefore, with the suspension device of this embodiment, since the elastic force can be adjusted by using gas, the elastic pressurizing means can be made small and lightweight, improving its mountability on a vehicle.

[0010] Furthermore, in a state where the elastic pressure means in the suspension system minimizes its elastic force, the elastic force generated by the suspension springs supporting the vehicle body when a predetermined weight is loaded may be balanced by the biasing force that biases the suspension springs while the movement of the movable spring receiver is restricted by a stopper. With a suspension system configured in this way, when a predetermined weight is loaded onto the vehicle body in a state where the elastic pressure means minimizes its elastic force, the movable spring receiver also displaces inward towards the housing when the suspension springs are compressed, so that the spring constant of the suspension system can be made smaller than the spring constant of the suspension springs.

[0011] Furthermore, the rear cushion unit comprises an outer shell, a shock absorber body having an outer shell and a rod inserted axially movably into the outer shell so as to be movable, capable of generating a damping force to suppress relative movement between the outer shell and the rod, a suspension device, and a fixed spring support provided on the rod to support the other end of the suspension spring, with the housing and movable spring support attached to the outer shell. The rear cushion unit configured in this way includes a suspension device, and since the spring constant of the suspension device can be changed, the ride comfort of the vehicle can be improved. In addition, the suspension device can be integrated with the shock absorber body and interposed between the vehicle body and the rear wheels of a saddle-type vehicle, making it easy to mount the suspension device on a saddle-type vehicle.

[0012] Furthermore, the rear cushion unit may include an annular bump cushion mounted on the outer circumference of the rod's non-outer shell end, and a bump stopper attached to the outer shell and axially opposed to the bump cushion. The housing may not restrict the movement of the movable spring receiver toward the suspension spring until the shock absorber body contracts and the bump cushion and bump stopper come into contact. With a rear cushion unit configured in this way, even if the shock absorber body contracts and the bump cushion and bump stopper come into contact when the spring constant of the suspension system is reduced, sufficient stroke length is ensured in the direction of contracting the pressure chamber of the movable spring receiver relative to the housing. As a result, the movable spring receiver and the housing do not collide until the bump cushion and bump stopper come into contact, preventing a sudden increase in the spring constant and causing a bumpy ride that would be unpleasant for the vehicle's occupants. [Effects of the Invention]

[0013] The suspension system and rear cushion unit of the present invention can improve ride comfort in a vehicle. [Brief explanation of the drawing]

[0014] [Figure 1] Figure 1 is a cross-sectional view of a rear cushion unit equipped with a suspension system according to one embodiment. [Figure 2] Figure 2 shows a rear cushion unit attached to a saddle-type vehicle. [Modes for carrying out the invention]

[0015] The present invention will be described based on the embodiments shown in the figures. As shown in Figures 1 and 2, in one embodiment, the suspension device S is integrated with the shock absorber body D to form a rear cushion unit RCU together with the shock absorber body D, and is interposed between the vehicle body F and the rear wheels W of a saddle-type vehicle M such as a motorcycle to elastically support the vehicle body F. In this embodiment, the suspension device S is described using an example in which the suspension device S is applied to the rear cushion unit RCU and interposed between the vehicle body F and the rear wheels W of a saddle-type vehicle M, but the suspension device S may be used in vehicles other than saddle-type vehicles M, either together with the shock absorber body D or separately and independently from the shock absorber body D.

[0016] The following describes in detail the suspension device S and the rear cushion unit RCU equipped with the suspension device S. First, as shown in Figure 1, the shock absorber body D in the rear cushion unit RCU includes a cylinder 1, a cylindrical rod 2 inserted into the cylinder 1 so as to be movable in the axial direction, a piston 3 connected to the rod 2 and inserted into the cylinder 1 so as to be movable in the axial direction, and which divides the inside of the cylinder 1 into an extension chamber R1 and a compression chamber R2, an outer shell 4 that covers the outer circumference of the cylinder 1 and forms an annular gap between it and the cylinder 1, a cap 5 that is attached to the outer circumference of the upper end of the outer shell 4 in Figure 1 and closes the upper end of the cylinder 1 in Figure 1, and a tank 6 held by the cap 5.

[0017] The cylinder 1 includes a flange 1a provided on the outer circumference of the upper end in Figure 1 and abutting against the upper end of the outer shell 4, a flange 1b provided on the outer circumference of the lower end in Figure 1 and fitting onto the inner circumference of the outer shell 4, and a hole 1c provided above the flange 1b and in close proximity to the flange 1b, which communicates the inside and outside of the cylinder 1.

[0018] The inside of cylinder 1 is divided into an extension chamber R1 and a compression chamber R2, which are filled with hydraulic fluid by a piston 3 that is inserted axially so as to be movable. The piston 3 is annular and is mounted on the outer circumference of the tip of a rod 2 that is inserted axially so as to be movable into cylinder 1, and has an extension port 3a and a compression port 3b that connect the extension chamber R1 and the compression chamber R2. An annular extension leaf valve 13 that opens and closes the extension port 3a is stacked on the upper end of piston 3 in Figure 1, and an annular compression leaf valve 14 that opens and closes the compression port 3b is stacked on the lower end of piston 3 in Figure 1. The inner circumference of both the extension leaf valve 13 and the compression leaf valve 14 is fixed to the outer circumference of rod 2, and by bending the outer circumference, they open the corresponding extension port 3a and compression port 3b, respectively, and provide resistance to the flow of hydraulic fluid passing through them.

[0019] Next, the outer shell 4 covers the outer circumference of the cylinder 1, with its upper end in Figure 1 abutting against the lower end of the upper flange 1a of the cylinder 1, and together with the cylinder 1, it forms an annular gap on the outer circumference of the cylinder 1 between flanges 1a and 1b. Furthermore, a hole 4a is provided near the upper end of the outer shell 4, connecting the inside and outside of the outer shell 4 and leading to the annular gap, and a threaded portion 4b is formed on the outer circumference of the outer shell 4 below the hole 4a in Figure 1.

[0020] Furthermore, an annular rod guide 7 is mounted on the inner circumference of the lower end of the outer shell 4 in Figure 1. A rod 2, which is movable in the axial direction within the cylinder 1, is inserted through the rod guide 7. Also mounted on the inner circumference of the rod guide 7 is an annular bush 8 that slides against the outer circumference of the rod 2 to guide its axial movement, and a seal ring 9 that seals the outer circumference of the rod 2. Furthermore, a seal ring 10 that is in close contact with the inner circumference of the outer shell 4 is mounted on the outer circumference of the rod guide 7. In this way, the space between the rod 2 and the rod guide 7 is sealed by the seal ring 9, and the space between the rod guide 7 and the outer shell 4 is sealed by the seal ring 10, thus sealing the inside of the cylinder 1 and the outer shell 4.

[0021] Also, at the lower end of the rod 2 in FIG. 1, a bracket 20 that can be connected to a swing arm SA that holds the rear wheel W in the saddle-type vehicle M is provided. Further, at the lower end of the rod 2 in FIG. 1, which is the outer periphery of the rod 2 and the anti-outer shell side end, an annular bump cushion 21 supported by the bracket 20 is mounted. On the other hand, an annular bump stopper 22 that axially faces the bump cushion 21 is attached to the inner periphery of the lower end of the outer shell 4. Therefore, when the rod 2 approaches the outer shell 4 in the axial direction and the shock absorber body D contracts to near the stroke end on the contraction side, the bump cushion 21 abuts against the bump stopper 22 and is compressed to generate a repulsive force, preventing further contraction of the shock absorber body D.

[0022] The cap 5 has a toped cylindrical shape having a cylindrical portion 5a and a bottom portion 5b, and the cylindrical portion 5a is screwed onto the screw portion 4b of the outer shell 4. When the cap 5 is screwed onto the outer shell 4 in this way, the flange 1a of the cylinder 1 is sandwiched between the outer shell 4 and the bottom portion 5b of the cap 5, and the cylinder 1 is fixed immovably to the outer shell 4 and the cap 5. The outer periphery of the cylindrical portion 5a on the lower end side in FIG. 1 has a smaller diameter than the upper end, and has a stepped portion 5a1 on the outer periphery.

[0023] Also, the cap 5 includes a bracket 5c that can be connected to the vehicle body F of the saddle-type vehicle M at the upper end of the bottom portion 5b, and a tank holding portion 5d that holds the tank 6 on the upper end side of the cylindrical portion 5a in FIG. 1.

[0024] The tank 6, held by the tank holder 5d, is divided into an oil chamber O, which is filled with hydraulic fluid, and a gas chamber G, which is filled with gas, by a free piston 6a housed axially movable inside. The oil chamber O is connected to the pressure chamber R2 by a passage 11 formed from the bottom 5b of the cap 5 to the tank holder 5d, and to the extension chamber R1 by a passage 12 formed from the cylindrical portion 5a of the cap 5 to the tank holder 5d, a hole 4a in the outer shell 4, the annular gap, and a hole 1c in the cylinder 1. The inside of the tank 6 may be divided into the oil chamber O and the gas chamber G by a flexible bladder or bellows instead of the free piston 6a.

[0025] Furthermore, the cap 5 is provided with an extension-side soft valve 15 and a compression-side soft valve 16 arranged in parallel with the passage 12, and an on / off valve 17 arranged in series with the extension-side soft valve 15 and the compression-side soft valve 16. The resistance exerted by the extension-side soft valve 15 on the flow of hydraulic fluid is smaller than the resistance exerted by the extension-side leaf valve 13 on the flow of hydraulic fluid, and the resistance exerted by the compression-side soft valve 16 on the flow of hydraulic fluid is smaller than the resistance exerted by the compression-side leaf valve 14 on the flow of hydraulic fluid. In addition, the on / off valve 17 opens when energized to activate the passage 12, and closes when not energized to block the passage 12.

[0026] The shock absorber body D is configured as described above. When the on / off valve 17 is closed and the shock absorber extends, the hydraulic fluid in the extension chamber R1, which is reduced by the downward movement of the piston 3 in Figure 1, moves through the extension port 3a and the extension leaf valve 13 to the expansion of the compression chamber R2. Since the on / off valve 17 is closed and the hydraulic fluid in the extension chamber R1 cannot pass through the passage 12, the entire flow rate of hydraulic fluid from the extension chamber R1 to the compression chamber R2 flows through the extension leaf valve 13. Therefore, the shock absorber body D generates a hard damping force that hinders the extension operation solely by the extension leaf valve 13. When the shock absorber body D extends, the rod 2 retracts from the cylinder 1, and the amount of hydraulic fluid in the cylinder 1 decreases by the volume of the rod 2 retracting from the cylinder 1. However, the missing amount of hydraulic fluid is supplied from the tank 6 to the cylinder 1 through the passage 11, compensating for the volume of the rod 2.

[0027] On the other hand, when the shock absorber body D contracts while the on / off valve 17 is closed, the hydraulic fluid in the compression chamber R2, which is reduced by the upward movement of the piston 3 in Figure 1, moves through the compression port 3b and the compression leaf valve 14 to the expansion chamber R1, which is expanded. Since the on / off valve 17 is closed and the hydraulic fluid in the compression chamber R2 cannot pass through the passage 12, the entire flow rate of hydraulic fluid from the compression chamber R2 to the expansion chamber R1 flows through the compression leaf valve 14. Therefore, the shock absorber body D generates a hard damping force that prevents contraction by the compression leaf valve 14 alone. When the shock absorber body D contracts, the rod 2 enters the cylinder 1, and the amount of hydraulic fluid in the cylinder 1 is excess by the volume of the rod 2 entering the cylinder 1. However, the excess hydraulic fluid is discharged from the cylinder 1 into the tank 6 through the passage 11, compensating for the volume of the rod 2.

[0028] When the shock absorber body D extends while the on / off valve 17 is open, the hydraulic fluid in the extension chamber R1, which is contracted by the downward movement of the piston 3 in Figure 1, can move not only through the extension port 3a but also through the extension soft valve 15 in the passage 12 to the expanded compression chamber R2. Since the resistance that the extension soft valve 15 exerts on the flow of hydraulic fluid is less than the resistance that the extension leaf valve 13 exerts on the flow of hydraulic fluid, the hydraulic fluid preferentially passes through the extension soft valve 15. Therefore, the shock absorber body D generates a soft damping force that mainly hinders the extension operation due to the extension soft valve 15.

[0029] On the other hand, when the shock absorber body D contracts while the on / off valve 17 is closed, the hydraulic fluid in the compression chamber R2, which is reduced by the upward movement of the piston 3 in Figure 1, can move to the expansion chamber R1, which is expanded not only by passing through the compression port 3b and the compression leaf valve 14 but also by passing through the compression soft valve 16 in the passage 12. Since the resistance that the compression soft valve 16 exerts on the flow of hydraulic fluid is less than the resistance that the compression leaf valve 14 exerts on the flow of hydraulic fluid, the hydraulic fluid preferentially passes through the compression soft valve 16. Therefore, the shock absorber body D generates a soft damping force that mainly hinders the contraction operation by the compression soft valve 16.

[0030] Thus, the shock absorber body D can switch between soft and hard damping force during expansion and contraction by opening and closing the on / off valve 17. The specific structure of the shock absorber body D is just one example, and is not limited to the above structure as long as it can generate damping force during expansion and contraction. Therefore, the shock absorber body D may, for example, have a structure with a reservoir between the outer shell 4 and the cylinder 1, or it may adopt a single-tube type structure in which the cylinder 1 is eliminated and the piston 3 is in sliding contact with the inner circumference of the outer shell 4.

[0031] Next, the suspension device S includes a suspension spring 30, a movable spring support 31 that supports the upper end in Figure 1 which is one end of the suspension spring 30 and is movable in the direction in which the suspension spring 30 expands and contracts, a housing 32 that is attached to the outer circumference of the cap 5 and allows the movable spring support 31 to move in the direction in which the suspension spring 30 expands and contracts, and forms a pressure chamber P between itself and the movable spring support 31 that contains liquid, a stopper 33 that prevents the movable spring support 31 from moving further toward the suspension spring when the movable spring support 31 moves toward the suspension spring side relative to the housing 32 and maximizes the pressure chamber P, and an elastic pressurizing means 34 that can pressurize the inside of the pressure chamber P by elastic force and can adjust the elastic force.

[0032] The suspension spring 30 is a coil spring, with one end, the upper end in Figure 1, supported by a movable spring support 31, and the other end, the lower end in Figure 1, supported by a fixed spring support 25 attached to a bracket 20 provided on the lower end in Figure 1 of the rod 2 of the shock absorber body D. The suspension spring 30 is interposed between the movable spring support 31 and the fixed spring support 25 in a compressed state, constantly biasing the shock absorber body D in the extension direction. When the rear cushion unit RCU is interposed between the body F and the rear wheels W of the saddle-type vehicle M, the suspension spring 30 compresses slightly under the weight of the body F, elastically supporting the body F. Therefore, when the shock absorber body D expands and contracts due to vibrations input from the road surface while the saddle-type vehicle M is running, the suspension spring 30 also expands and contracts together with the shock absorber body D.

[0033] The movable spring support 31 is cylindrical and comprises a large-diameter portion 31a with a larger inner and outer diameter on the suspension spring side, a small-diameter portion 31b with a smaller inner and outer diameter on the opposite side of the suspension spring than the inner and outer diameter of the large-diameter portion 31a, and a flange-shaped pressure-receiving portion 31c connecting the large-diameter portion 31a and the small-diameter portion 31b. The inner diameter of the small-diameter portion 31b, which is the smallest inner diameter of the movable spring support 31, is larger than the outer diameter of the small-diameter portion at the lower end of the cylindrical portion 5a of the outer shell 4 and the cap 5. The movable spring support 31 can move in the vertical direction in Figure 1, which is the direction of expansion and contraction of the suspension spring 30, without interfering with the outer shell 4 and the cap 5. The inner circumference of the small-diameter portion 31b may be brought into sliding contact with the outer circumference of the small-diameter portion of the cylindrical portion 5a of the cap 5. In addition, in the movable spring support 31 of this embodiment, the outer diameter of the pressure-receiving portion 31c is larger than the outer diameter of the large-diameter portion 31a. Furthermore, a seal ring 31d is fitted into an annular groove (not shown) provided on the outer circumference of the pressure-receiving portion 31c of the movable spring receiver 31.

[0034] Furthermore, a seat ring 35 is interposed between the lower end of the large-diameter portion 31a of the movable spring receiver 31 in Figure 1 and the upper end of the suspension spring 30 in Figure 1. The seat ring 35 comprises a fitting portion 35a that fits onto the inner circumference of the suspension spring 30, a flange-shaped seat portion 35b provided on the outer circumference of the upper end of the fitting portion 35a in Figure 1 and contacting the upper end of the suspension spring 30 in Figure 1, and an annular positioning portion 35c that curves from the outer circumference of the seat portion 35b toward the large-diameter portion and is loosely fitted onto the outer circumference of the large-diameter portion 31a. When the seat portion 35b of the seat ring 35 is stacked on the end of the large-diameter portion 31a, rotation in the circumferential direction is permitted relative to the movable spring receiver 31, while the positioning portion 35c faces the outer circumference of the large-diameter portion 31a, preventing it from falling off radially relative to the movable spring receiver 31. Since the suspension spring 30 is a coil spring, its ends rotate slightly in the circumferential direction as it expands and contracts. However, by stacking a circumferentially rotatable seat ring 35 on the movable spring support 31, the rotation of the suspension spring 30 can be prevented from being transmitted to the movable spring support 31. The movable spring support 31 is equipped with a seal ring 31d to form a pressure chamber P together with the housing 32, and is not easily rotated in the circumferential direction. Therefore, by providing the seat ring 35 in this way, the rotation of the movable spring support 31 can be prevented, and deterioration of the seal ring 31d can be prevented. Note that the seat ring 35 can be omitted if it is not needed, and the suspension spring 30 may be directly in contact with the end of the movable spring support 31.

[0035] The housing 32 comprises an annular base 32a that abuts against the stepped portion 5a1 on the outer circumference of the cap 5, and an annular socket 32b that hangs down from the lower outer circumference of the base 32a in Figure 1. When the housing 32 is attached to the cap 5 with the housing 32 positioned on the outer circumference of the cylindrical portion 5a of the cap 5 and in contact with the stepped portion 5a1, it forms an annular gap between the housing 32 and the cylindrical portion 5a of the cap 5 into which the small-diameter portion 31b of the movable spring receiver 31 can be inserted, and also forms an annular space within the socket 32b into which the pressure-receiving portion 31c and the large-diameter portion 31a of the movable spring receiver 31 can be inserted. In this way, the housing 32 and the movable spring receiver 31 are attached to the outer shell 4 via the cap 5. The housing 32 and the movable spring receiver 31 may also be attached to the outer shell 4 via the cap 5 or other parts connected to the outer shell 4, or they may be attached directly to the outer shell 4.

[0036] The base portion 32a is fixed to the cap 5 in contact with the stepped portion 5a1 of the cap 5, with its inner diameter set to a diameter that allows it to slide against the outer circumference of the small diameter portion 31b of the movable spring receiver 31. A seal ring 32c is fitted in an annular groove (not shown) on the inner circumference of the base portion 32a, which slides against the outer circumference of the small diameter portion 31b of the movable spring receiver 31. The pressure-receiving portion 31c of the movable spring receiver 31 is slidably inserted into the socket 32b, and the space between the socket 32b and the pressure-receiving portion 31c is sealed by the seal ring 31d on the outer circumference of the pressure-receiving portion 31c. When the movable spring receiver 31 is inserted into the housing 32, the outer circumference of the pressure-receiving portion 31c slides against the inner circumference of the socket 32b, and the outer circumference of the small diameter portion 31b slides against the inner circumference of the base portion 32a, so that it can move vertically in the axial direction in Figure 1 without axial wobble while being guided by the housing 32. Furthermore, the opposing surface 31c1 of the pressure-receiving portion 31c of the movable spring receiver 31, which is the lower end surface in Figure 1, and the opposing surface 32a2 of the base portion 32a of the housing 31, which is the upper end surface in Figure 1, are opposite each other in the axial direction. When the movable spring receiver 31 moves upward in Figure 1 towards the housing 32 and the opposing surfaces 31c1 and 32a1 come into contact with each other, further upward movement in Figure 1 away from the housing 32 is restricted.

[0037] Furthermore, when the movable spring receiver 31 is inserted into the housing 32, a pressure chamber P is formed between the housing 32 and the movable spring receiver 31 by an annular gap surrounded by the small-diameter portion 31b and pressure-receiving portion 31c of the movable spring receiver 31 and the base portion 32a and socket 32b of the housing 32, which contains liquid. In this embodiment of the suspension device S, the liquid contained in the pressure chamber P is hydraulic fluid, but it may be a liquid other than hydraulic fluid. Since the space between the movable spring receiver 31 and the housing 32 is sealed by the seal rings 31d and 32c, the pressure chamber P is sealed, and leakage of the liquid in the pressure chamber P to the outside of the pressure chamber P is prevented.

[0038] Furthermore, since the pressure inside the pressure chamber P acts on the upper end of the pressure-receiving portion 31c of the movable spring receiver 31 in Figure 1, the movable spring receiver 31 is constantly biased toward the suspension spring side, which is downward in Figure 1, by a force equal to the product of the area of ​​the pressure-receiving portion 31c facing the pressure chamber P in Figure 1 and the pressure inside the pressure chamber P.

[0039] Furthermore, a stopper 33 is attached to the outer circumference of the socket 32b of the housing 32. The stopper 33 comprises a cylindrical portion 33a having a threaded portion on its inner circumference and being screwed onto the outer circumference of the socket 32b, and an annular stopper portion 33b extending radially from the inner circumference of the cylindrical portion 33a. The inner diameter of the stopper portion 33b is larger than the outer diameter of the large diameter portion 31a of the movable spring receiver 31, and smaller than the inner diameter of the socket 32b. When the stopper 33 is attached to the socket 32b of the housing 32, the inner circumference of the stopper portion 33b faces the outer circumference of the lower end of the pressure receiving portion 31c of the movable spring receiver 31 in the axial direction in Figure 1. When the movable spring receiver 31 moves to its maximum extent toward the suspension spring relative to the housing 32, the stopper portion 33b of the stopper 33 comes into contact with the outer circumference of the lower end of the pressure-receiving portion 31c of the movable spring receiver 31, preventing the movable spring receiver 31 from being displaced any further toward the suspension spring, which is lower in Figure 1, relative to the housing 32. In this way, the stopper 33 prevents the movable spring receiver 31 from moving toward the suspension spring relative to the housing 32 and maximizing the pressure chamber P. Therefore, the movable spring receiver 31 can stroke from a position where the pressure-receiving portion 31c comes into contact with the base portion 32a of the housing 32 and minimizes the pressure chamber P, to a position where the pressure-receiving portion 31c comes into contact with the stopper portion 33b of the stopper 33 and maximizes the pressure chamber P.

[0040] As described above, the movable spring receiver 31 has a large diameter portion 31a, a small diameter portion 31b, and a pressure-receiving portion 31c, and the housing 32 has a base portion 32a that slides against the outer circumference of the small diameter portion 31b, and a socket 32b that hangs down from the base portion 32a and into which the pressure-receiving portion 31c is slidably inserted. Therefore, the sliding surfaces of both the housing 32 and the movable spring receiver 31 that moves in and out of the housing 32 are not exposed to the outside of the suspension device S. Thus, with the suspension device S equipped with the movable spring receiver 31 and housing 32 configured as described above, the sliding surfaces of both the movable spring receiver 31 and the housing 32 can be protected, and leakage of liquid from inside the pressure chamber P can be prevented. Furthermore, the inner circumferential surface of the stopper portion 33b of the stopper 33 faces the outer circumferential surface of the large-diameter portion 31a of the movable spring receiver 31. This not only functions as a stopper to restrict the movement of the movable spring receiver 31, but also covers the open end at the lower end of the housing 32 in Figure 1, thus preventing dust and water from entering the housing 32. The movable spring receiver 31 may be mounted on the outer circumference of the housing 32, as long as it can form a pressure chamber P between itself and the housing 32 and move relative to the housing 32 in the direction of expansion and contraction of the suspension spring 30.

[0041] The elastic pressurizing means 34 for adjusting the pressure inside the pressure chamber P comprises a container 37, a movable partition wall 38 that is movably inserted into the container 37 and forms a space that communicates with the pressure chamber P through a pipe 36 inside the container 37, and an elastic partition wall 39 that divides the space into an air chamber A filled with gas and a liquid chamber B that communicates with the pressure chamber P.

[0042] The container 37 is cylindrical, and one end is closed by a cap 40 that holds an elastic partition wall 39 formed by a bladder. The other end of the container 37 is fitted with a screw-on cap 41, which is annular and has a threaded portion on its inner circumference. A screw shaft 42, whose tip protrudes into the container 37, is screwed onto the inner circumference of the screw-on cap 41. Furthermore, a nut 43 is screwed onto the outer circumference of the screw shaft 42. When the nut 43 is rotated relative to the screw shaft 42 and brought into contact with the screw-on cap 41, the nut 43 and the screw-on cap 41 work together in a double-nut manner to prevent the rotation of the screw shaft 42 and fix the screw shaft 42 to the screw-on cap 41. Furthermore, if the nut 43 is loosened while the screw shaft 42 is fixed to the screwed cap 41, rotation of the screw shaft 42 relative to the screwed cap 41 is permitted, and this rotational operation of the screw shaft 42 relative to the screwed cap 41 allows axial movement of the screw shaft 42 relative to the container 37. The rear end of the screw shaft 42 that protrudes outside the container 37 is equipped with a head 42a that allows it to be gripped by a tool, and when it protrudes to its maximum extent into the container 37, the head 42a contacts the lower end of the nut 43 in Figure 1 that abuts the screwed cap 41, preventing it from entering the container 37 any further.

[0043] Furthermore, a movable partition wall 38 is attached to the tip of the screw shaft 42 so as to be axially slidable within the container 37. The movable partition wall 38 forms a space within the container 37 that communicates with the pressure chamber P, and the volume of this space is changed by the displacement of the movable partition wall 38 together with the screw shaft 42 within the container 37 as the screw shaft 42 moves axially relative to the container 37. The means for displacing the movable partition wall 38 relative to the container 37 may be a mechanism other than the feed screw mechanism composed of the screw shaft 42 and the screwed cap 41, and the design can be modified as appropriate. However, by using the feed screw mechanism, the movable partition wall 38 can be displaced steplessly relative to the container 37 with a small torque, and the pressure in the pressure chamber P can be adjusted steplessly by the elastic pressurizing means 34. Alternatively, power from an actuator such as a motor or pneumatic pressure may be used to displace the movable partition wall 38 relative to the container 37. Furthermore, although the movable partition wall 38 is a free piston that is slidably inserted into the container 37, any movable partition wall that can change the volume of the space partitioned by the movable partition wall 38 within the container 37, such as a metal bellows, is acceptable.

[0044] The space within the container 37 is connected to the pressure chamber P via piping 36. An elastic partition wall 39 is housed within the space in the container 37, and the elastic partition wall 39 is filled with gas. The space within the container 37, outside the elastic partition wall 39, is filled with liquid. By inserting the movable partition wall 38 into the container 37, the space partitioned by the movable partition wall 38 is divided by the elastic partition wall 39 into a gas chamber A filled with gas and a liquid chamber B filled with liquid, with liquid chamber B connected to the pressure chamber P via piping 36. The liquid filling liquid chamber B may be the same liquid as the liquid filling the pressure chamber P, and may be, for example, hydraulic oil, an aqueous ethylene glycol solution, or other liquids. The elastic partition wall 39 may also be a diaphragm or a bellows.

[0045] Since compressed gas is filled into the air chamber A within the elastic partition wall 39, the pressure in air chamber A acts on the pressure chamber P via the liquid chamber B. In this way, the elastic pressurizing means 34 functions as an air spring, constantly pressurizing the pressure chamber P with the elastic force generated by the gas in air chamber A. When the movable partition wall 38 is displaced axially within the container 37 by rotating the screw shaft 42, reducing the volume of the space, the gas in air chamber A is compressed, and the gas generates a greater elastic force, which can increase the pressure in the pressure chamber P. Conversely, when the movable partition wall 38 is displaced axially within the container 37 by rotating the screw shaft 42, increasing the volume of the space, air chamber A expands, reducing the degree of gas compression, decreasing the elastic force generated by the gas, and thus lowering the pressure in the pressure chamber P.

[0046] Furthermore, when the movable bulkhead 38 penetrates the container 37 to its maximum extent to minimize the volume of the space, the elastic force of the gas in the air chamber A is maximized, and the pressure exerted by the elastic pressurizing means 34 on the pressure chamber P is maximized. In this state, the force that the movable spring receiver 31 receives from the pressure chamber P in the direction of compressing the suspension spring 30 is set to be greater than the force that the movable spring receiver 31 receives from the suspension spring 30 in the direction of compressing the pressure chamber P when the buffer body D is most compressed and the suspension spring 30 is at its most contracted state. Therefore, when the movable bulkhead 38 penetrates the container 37 to its maximum extent to minimize the volume of the space, the force received from the suspension spring 30 does not cause the movable spring receiver 31 to displace upward in Figure 1, and it always remains at the lowest position where it contacts the stopper 33 and does not displace from that position.

[0047] On the other hand, when the movable bulkhead 38 is retracted to its maximum extent within the container 37 to maximize the volume of the space, the elastic force of the gas in the air chamber A is minimized, and the pressure that the elastic pressurizing means 34 exerts on the pressure chamber P is also minimized. In this state, the force that the movable spring receiver 31 receives from the pressure chamber P in the direction of compressing the suspension spring 30 is balanced by the force that the movable spring receiver 31 receives from the compressed suspension spring 30, which is loaded with a predetermined weight on the body F of the saddle-type vehicle M, in the direction of compressing the pressure chamber P. The predetermined weight is set to a weight approximately equal to the weight of one passenger, for example, in the range of 50 kg to 80 kg. The pressure of the gas in the air chamber A, the pressure receiving area of ​​the pressure chamber P of the movable spring receiver 31, and the specifications of the suspension spring 30 are set so that the force that the movable spring receiver 31 receives from the pressure chamber P and the force that the movable spring receiver 31 receives from the suspension spring 30 are balanced when one passenger is riding in the saddle-type vehicle M.

[0048] In the suspension device S and rear cushion unit RCU configured as described above, an elastic pressurizing means 34 is provided to pressurize the pressure chamber P by elastic force. When the movable bulkhead 38 is positioned in the container 37 to minimize the volume of space, the pressure of the gas in the air chamber A becomes maximum and acts in the pressure chamber P. In this state, as mentioned above, even when the suspension spring 30 is fully contracted within the strokeable range of the shock absorber body D, the elastic force of the suspension spring 30 cannot exceed the force that pushes the movable spring receiver 31 toward the suspension spring 30 due to the pressure in the pressure chamber P. As a result, the movable spring receiver 31 does not displace from the position where it is maximally retracted from the housing 32 by the stopper 33.

[0049] Therefore, when the movable bulkhead 38 is positioned in the container 37 to minimize the volume of space, the position of the movable spring support 31 does not change. As a result, only the suspension spring 30 expands and contracts in conjunction with the expansion and contraction of the shock absorber body D, and the spring constant of the suspension device S becomes the spring constant of the suspension spring 30, taking the largest possible value.

[0050] In contrast, when the movable bulkhead 38 is positioned to maximize the volume of space within the container 37, the pressure of the gas in the air chamber A becomes minimal and acts within the pressure chamber P. In this state, as described above, the force exerted upward by the suspension spring 30, which contracts by supporting the body F of the saddle-type vehicle M loaded with a predetermined weight, on the movable spring receiver 31 balances the force exerted by the movable spring receiver 31 toward the suspension spring 30 due to the pressure in the pressure chamber P. When the suspension spring 30, which has contracted by supporting the body F of the saddle-type vehicle M loaded with a predetermined weight, contracts further due to vibrations input while the saddle-type vehicle M is running, the elastic force generated by the suspension spring 30 increases, and the force exerted upward by the suspension spring 30 on the movable spring receiver 31 becomes greater than the force exerted by the movable spring receiver 31 toward the suspension spring 30 due to the pressure in the pressure chamber P, causing the movable spring receiver 31 to be displaced upward in Figure 1. As the movable spring receiver 31 is displaced upward in Figure 1, the pressure chamber P is reduced, liquid is discharged from the pressure chamber P toward the container 37, the volume of the air chamber A is reduced, and the force pressing the movable spring receiver 31 toward the suspension spring 30 due to the pressure in the pressure chamber P increases. This upward displacement of the movable spring receiver 31 in Figure 1 continues until the force with which the suspension spring 30 pushes the movable spring receiver 31 upward and the force with which the pressure in the pressure chamber P pushes the movable spring receiver 31 toward the suspension spring 30 balance out. Furthermore, even if the shock absorber body D is compressed, the stroke length is ensured so that the opposing surface 31c1, which is the upper end surface in Figure 1 of the pressure-receiving portion 31c of the movable spring receiver 31, does not come into contact with the opposing surface 32a1, which is the lower end surface in Figure 1 of the base portion 32a of the housing 32, until the bump cushion 21 and the bump stopper 22 come into contact. Therefore, when the suspension spring 30, which has contracted by supporting the body F of the saddle-type vehicle M loaded with a predetermined weight, contracts further due to vibrations input during the movement of the saddle-type vehicle M, the movable spring receiver 31 also displaces relative to the housing 32. As a result, the body F is elastically supported by the series-connected suspension spring 30 and the elastic pressurizing means 34 which functions as an air spring. The spring constant of the suspension device S is the sum of the spring constant of the suspension spring 30 and the spring constant of the elastic pressurizing means 34 which functions as an air spring.In this case, if the spring constant of the suspension spring 30 is k1 and the spring constant of the elastic pressurizing means 34 that functions as an air spring is k2, then the spring constant K of the suspension device S is K = k1·k2 / (k1+k2), which is smaller than the spring constant k1 when only the suspension spring 30 is compressed or compressed.

[0051] On the other hand, when the suspension spring 30, which has been compressed by supporting the body F of the saddle-type vehicle M loaded with a predetermined weight, extends due to vibrations input while the saddle-type vehicle M is running, the elastic force of the suspension spring 30 decreases, so the movable spring receiver 31 does not displace from the position positioned by the stopper 33. Therefore, the spring constant of the suspension device S becomes equal to the spring constant of the suspension spring 30.

[0052] In this embodiment, the suspension device S and the rear cushion unit RCU to which the suspension device S is applied can be switched between a state in which only the suspension spring 30 expands and contracts and a state in which not only the suspension spring 30 but also the movable spring receiver 31 can be displaced relative to the housing 32 by adjusting the pressure in the pressure chamber P with the elastic pressurizing means 34, thereby adjusting the spring constant in the suspension device S. When the movable bulkhead 38 is retracted to its maximum extent within the container 37 to maximize the volume of the space, the force that the movable spring receiver 31 receives from the pressure chamber P in the direction of compressing the suspension spring 30 is balanced by the force that the movable spring receiver 31 receives from the compressed suspension spring 30 in the direction of compressing the pressure chamber P when a predetermined weight is loaded on the body F of the saddle-type vehicle M. The setting range of the predetermined load should be set to less than the maximum load that can be supported by the elastic force generated when the suspension spring 30 contracts within the stroke range of the shock absorber body D. If a predetermined load is set within this range, the movable spring support 31 can be displaced within the stroke range of the shock absorber body D, making it possible to change the spring constant of the suspension device S. Furthermore, even if the position of the movable bulkhead 38 is not set to maximize the volume of the space inside the container 37, if the movable spring support 31 is displaced relative to the housing 32 in accordance with the expansion and contraction of the suspension spring 30, the degree of contraction of the suspension spring 30 and the degree of decrease in the spring constant can be adjusted when the spring constant of the suspension device S decreases.

[0053] As described above, the suspension device S of this embodiment includes a suspension spring 30 that supports the body F of a saddle-type vehicle (vehicle) M, a movable spring support 31 that supports one end of the suspension spring 30 and is displaceable in the direction of expansion and contraction of the suspension spring 30, a housing 32 that allows the movable spring support 31 to move in the direction of expansion and contraction of the suspension spring 30 and forms a pressure chamber P for containing liquid between the movable spring support 31 and the movable spring support 31, a stopper 33 that prevents the movable spring support 31 from moving toward the suspension spring side when the movable spring support 31 moves toward the suspension spring side relative to the housing 32 and maximizes the pressure chamber P, and an elastic pressurizing means 34 that can pressurize the inside of the pressure chamber P by elastic force and can adjust the elastic force.

[0054] In the suspension device S configured in this way, the elastic pressurizing means 34 pressurizes the inside of the pressure chamber P with elastic force, and the movable spring support 31 supports one end of the suspension spring 30. Therefore, by adjusting the pressure that the elastic pressurizing means 34 applies to the pressure chamber P, the movable spring support 31 can be fixed immovably in the position restricted by the stopper 33, and the movable spring support 31 can be displaced relative to the housing 32 according to the degree of compression of the suspension spring 30. Furthermore, since the elastic pressurizing means 34 pressurizes the pressure chamber P with elastic force, when the movable spring support 31 is displaced relative to the housing 32, the movable spring support 31 receives the elastic force of the elastic pressurizing means 34 and functions as a spring together with the suspension spring 30, thus reducing the spring constant in the suspension device S.

[0055] As described above, with the suspension system S of this embodiment, the overall spring constant of the suspension system S can be changed by adjusting the elastic force in the elastic pressurizing means 34, thereby improving the ride comfort in the vehicle.

[0056] Furthermore, in the suspension device S of this embodiment, the pressure chamber P contains liquid, and the elastic force of the elastic pressurizing means 34 is transmitted to the movable spring receiver 31 using the liquid as a medium. Therefore, proven liquid seal rings can be used for the seal rings 31d and 32c that seal the inside of the pressure chamber P, improving practicality.

[0057] Furthermore, the elastic pressurizing means 34 in the suspension device S of this embodiment comprises a container 37, a movable partition wall 38 that is movably inserted into the container 37 and partitions a space within the container 37 that communicates with the pressure chamber P, and a gas and a liquid contained within the container 37. With the suspension device S configured in this way, the elastic pressurizing means 34 functions as an air spring and adjusts the degree of compression of the gas by the displacement of the movable partition wall 38 within the container 37, thereby adjusting the elastic force acting in the pressure chamber P. Therefore, with the suspension device S of this embodiment, since the elastic force can be adjusted by utilizing the gas, the elastic pressurizing means 34 can be made small and lightweight, improving its mountability on a vehicle. Alternatively, the elastic pressurizing means 34 may be configured by eliminating the gas chamber A and filling only the space partitioned within the container 37 by the movable partition wall 38 with liquid, and adjusting the pressure acting in the pressure chamber P by biasing the movable partition wall 38 with a coil spring or the like and adjusting the elastic force of the coil spring or the like. Furthermore, the elastic pressurizing means 34 may be configured to include a metal bellows that stores liquid with its inner side communicating with the pressure chamber P, a spring or air spring that biases the metal bellows in a compressive direction, and an adjusting means for adjusting the elastic force of the spring or air spring. The adjusting means can be, for example, one that can displace the end of the spring or air spring on the side opposite the metal bellows, so a feed screw mechanism or the like in the elastic pressurizing means 34 described above can be used.

[0058] Furthermore, the elastic pressurizing means 34 of this embodiment is divided into an air chamber A and a liquid chamber B by an elastic partition wall 39, preventing gas from entering the pressure chamber P. In the suspension device S configured in this way, the elastic force of the gas is used to pressurize the pressure chamber P, but liquid seal rings can be used for the seal rings 31d and 32c that seal the inside of the pressure chamber P, eliminating the need to seal the gas, which is difficult to seal. Therefore, with the suspension device S of this embodiment, even if the pressure inside the pressure chamber P is increased by utilizing the elastic force of the gas, it is possible to use seal rings 31d and 32c that prevent liquid leakage, improving practicality. Note that if the gas inside the container 37 can be prevented from flowing into the pressure chamber P without using the elastic partition wall 39, the elastic partition wall 39 can be omitted, but using the elastic partition wall 39 has the advantage of eliminating concerns about gas entering the pressure chamber P.

[0059] Furthermore, in the suspension device S of this embodiment, when the elastic pressurizing means 34 minimizes its elastic force, the resilient force generated by the suspension spring 30 supporting the vehicle body F when a predetermined weight is loaded is balanced by the biasing force that biases the suspension spring 30 while the movement of the movable spring receiver 31 is restricted by the stopper 33. With the suspension device S configured in this way, when the elastic pressurizing means 34 minimizes its elastic force and a predetermined weight is loaded onto the vehicle body F of the saddle-type vehicle (vehicle) M, the movable spring receiver 31 also displaces inward towards the housing 32 when the suspension spring 30 is compressed, so that the spring constant of the suspension device S can be made smaller than the spring constant of the suspension spring 30. If the predetermined weight is set to approximately the weight of one passenger, the spring constant of the suspension device S installed in the saddle-type vehicle M during vehicle operation can be made smaller than the spring constant of the suspension spring 30, thereby achieving a ride comfort preferred by the passenger of the saddle-type vehicle M.

[0060] Furthermore, the rear cushion unit RCU of this embodiment includes an outer shell 4, a rod 2 inserted into the outer shell 4 so as to be movable in the axial direction, a shock absorber body D capable of generating a damping force to suppress relative movement between the outer shell 4 and the rod 2, a suspension device S, and a fixed spring support 25 provided on the rod 2 to support the other end of the suspension spring 30, with the housing 32 and movable spring support 31 provided on the outer shell 4. With the rear cushion unit RCU configured in this way, the suspension device S is provided, so the spring constant of the suspension device S can be changed, thereby improving the ride comfort in the vehicle. In addition, the suspension device S can be integrated with the shock absorber body D and interposed between the body F and the rear wheels W of a saddle-type vehicle (vehicle) M, making it easy to mount the suspension device S on a saddle-type vehicle (vehicle) M.

[0061] Furthermore, the rear cushion unit RCU of this embodiment includes an annular bump cushion 21 mounted on the outer circumference of the rod 2's end opposite the outer shell, and a bump stopper 22 attached to the outer shell 4 and facing the bump cushion 21 in the axial direction. The housing 32 does not restrict the movement of the movable spring receiver 31 toward the suspension spring side until the shock absorber body D contracts and the bump cushion 21 and bump stopper 22 come into contact. With the rear cushion unit RCU of this embodiment configured in this way, even if the shock absorber body D contracts and the bump cushion 21 and bump stopper 22 come into contact when the spring constant of the suspension device S is reduced, a sufficient stroke length is secured in the direction of contracting the pressure chamber P of the movable spring receiver 31 relative to the housing 32. Therefore, the movable spring receiver 31 and the housing 32 do not collide until the bump cushion 21 and bump stopper 22 come into contact. As a result, the spring constant does not suddenly increase, preventing the occupants of the saddle-type vehicle (vehicle) M from experiencing a bumpy ride and causing discomfort.

[0062] Note that the shape and structure of the movable spring support 31 and housing 32 are examples and can be modified as appropriate. For example, when the suspension device S is applied to the shock absorber body D, the housing 32 may be attached to the outer circumference of the outer shell 4, and the movable spring support 31 may be made to slide against the outer circumference of the outer shell 4 in addition to the housing 32.

[0063] Although preferred embodiments of the present invention have been described in detail above, modifications, alterations, and changes are permitted as long as they do not deviate from the scope of the claims. [Explanation of Symbols]

[0064] 2...Rod, 4...Outer shell, 21...Bump cushion, 22...Bump stopper, 25...Fixed spring receiver, 30...Suspension spring, 31...Movable spring receiver, 32...Housing, 33...Stopper, 34...Elastic pressurizing means, 37...Container, 38...Movable bulkhead, D...Buffer body, F...Vehicle body, M...Saddle-type vehicle (vehicle), P...Pressure chamber, RCU...Rear cushion unit, S...Suspension device, W...Rear wheel

Claims

1. Suspension springs that support the vehicle body, A movable spring support that supports one end of the suspension spring and is displaceable in the direction of expansion and contraction of the suspension spring, A housing that allows the movable spring support to move in the direction of expansion and contraction of the suspension spring, while forming a pressure chamber for containing liquid between the movable spring support and the movable spring support, A stopper prevents the movable spring support from moving any further toward the suspension spring when it moves toward the suspension spring relative to the housing to maximize the pressure chamber, The system comprises elastic pressurizing means capable of pressurizing the pressure chamber by elastic force and capable of adjusting said elastic force. A suspension system characterized by the following features.

2. The elastic pressurizing means is Container and A movable partition wall is movably inserted into the container and divides a space within the container that communicates with the pressure chamber, The container has a gas and a liquid contained within it. The suspension device according to claim 1.

3. When the elastic pressurizing means minimizes the elastic force, the elastic force generated by the suspension spring supporting the vehicle body when a predetermined weight is loaded is balanced by the biasing force that biases the suspension spring while the movement of the movable spring support is restricted by the stopper. The suspension device according to claim 1.

4. A shock absorber body having an outer shell and a rod inserted into the outer shell so as to be movable in the axial direction, and capable of generating a damping force to suppress relative movement between the outer shell and the rod, A suspension device according to any one of claims 1 to 3, The rod is provided with a fixed spring support that supports the other end of the suspension spring, The housing and the movable spring support are attached to the outer shell. A rear cushion unit characterized by the following features.

5. An annular bump cushion is attached to the outer circumference of the end of the rod opposite the outer shell, The outer shell is equipped with a bump stopper that is attached to the bump cushion and faces it in the axial direction, Until the shock absorber body contracts and the bump cushion and the bump stopper come into contact, the housing does not restrict the movement of the movable spring support toward the opposite suspension spring side. The rear cushion unit according to feature 4.

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