WO2020195702A1

WO2020195702A1 - Suspension device

Info

Publication number: WO2020195702A1
Application number: PCT/JP2020/009649
Authority: WO
Inventors: 鈴木　達也; 近藤　卓宏; 隆久望月
Original assignee: Ｋｙｂ株式会社
Priority date: 2019-03-27
Filing date: 2020-03-06
Publication date: 2020-10-01
Also published as: JP2020159504A

Abstract

A suspension device (S1) according to the present invention comprises: a single-rod-type shock absorber main unit (D1) that comprises a cylinder (1), a piston (2) movably inserted into the cylinder (1), an extension-side chamber (R1) and a compression-side chamber (R2) within the cylinder (1), the extension-side chamber (R1) and the compression-side chamber (2) being partitioned by the piston (2), and a piston rod (3) linked to the piston (2) which is movably inserted into the cylinder (1), and that exhibits damping force by fluid entering and exiting the cylinder (1) when the single-rod-type shock absorber main unit (D1) extends and compresses; a suspension spring (8) that biases the shock absorber main unit (D1) in the extending direction; a compression chamber (R3) that communicates with the compression-side chamber (R2) and compresses within inside of the cylinder (1) that is under biasing force from the suspension spring (8); and a fluid supply-and-discharge source (F) that is capable of supplying and discharging fluid to and from the compression chamber (R3).

Description

Suspension device

The present invention relates to a suspension device.

The suspension device is, for example, provided between a shock absorber body that generates a damping force when expanding and contracting, and a suspension spring that urges the shock absorber body in the extension direction, and is interposed between the vehicle body and the axle. Then, the suspension device elastically supports the vehicle body with the suspension spring to alleviate the vibration input from the axle side to the vehicle body side, and damps the vibration of the vehicle body with the shock absorber body.

In addition, some suspension devices are equipped with a jack that drives a spring seat that supports the lower end of the suspension spring provided on the outer periphery of the shock absorber body in the vertical direction in order to adjust the vehicle height. According to such a suspension device, even if the vehicle height fluctuates due to changes in the load capacity loaded on the vehicle body and the number of passengers, the spring seat can be moved up and down to adjust the vehicle height to the optimum value and the passenger's height. When getting on and off, the vehicle height can be lowered to facilitate the getting on and off of passengers (see, for example, Patent Document 1).

JP2014-084972A

The suspension device described above has a structure in which a suspension spring and a jack are arranged on the outer periphery of the shock absorber body, and the thrust of the jack is a value obtained by multiplying the internal pressure by the pressure receiving area of the jack, but the weight of the vehicle body. Depending on the case, it may be difficult to adjust the vehicle height unless a large jack pressure receiving area is secured. If an attempt is made to increase the pressure receiving area of the jack, the outer diameter of the jack becomes large, so that the suspension device becomes large and the weight of the suspension device becomes heavy.

Therefore, an object of the present invention is to provide a small and lightweight suspension device even if the vehicle height can be adjusted.

The suspension device in the problem-solving means of the present invention includes a cylinder, a piston that is movably inserted into the cylinder, an extension side chamber and a compression side chamber that are partitioned by the piston in the cylinder, and a piston that is movably inserted into the cylinder. A shock absorber body that has a piston rod connected to the cylinder and exerts a damping force by allowing liquid to flow in and out of the cylinder during expansion and contraction, and a suspension spring that urges the shock absorber body in the extension direction are communicated with the compression side chamber. It is equipped with a pressurizing chamber that pressurizes the inside of the cylinder by receiving urging force from a suspension spring, and a liquid supply / discharge source that can supply and discharge liquid to the pressurizing chamber. In the suspension device configured in this way, the vehicle height can be adjusted by supplying and discharging the liquid to and from the pressurizing chamber by the liquid supply and discharge source, and the effective pressure receiving area is determined by the pressure receiving area in the pressurizing chamber and the cross-sectional area of the piston rod. A large effective pressure receiving area can be secured as a sum.

Further, the liquid supply / exhaust source in the suspension device may have a constant-capacity pump, and according to the suspension device configured in this way, a vehicle aiming at the vehicle height only by controlling the rotation amount of the pump. Since it can be adjusted to the height, it is easy to adjust the vehicle height.

Further, the pressurizing chamber may be partitioned by a hollow housing and a movable spring seat movably fitted to the housing and urged by a suspension spring, according to the suspension device configured in this way. It is easy to install the pressurizing chamber in the shock absorber body.

Further, the housing may be mounted on the outer circumference of the cylinder, and the movable spring seat may be slidably mounted on both the outer circumference of the cylinder and the inner circumference of the housing. When the suspension device is configured in this way, the cylinder can be used as a forming component of the pressurizing chamber, the pressurizing chamber can be formed on the outer circumference of the cylinder with the minimum number of parts, and the outer diameter is also a double cylinder type buffer having a reservoir on the outer circumference of the cylinder. It only needs to be a cylinder and can be mounted on a vehicle without difficulty.

Further, the housing is attached to the piston rod, the movable spring seat is slidably attached to both the outer circumference of the piston rod and the inner circumference of the housing, and the pressurizing chamber and the compression side chamber are communicated by a passage provided in the piston rod. It may have been. According to the suspension device configured as described above, the piston rod can be used as a forming component of the pressurizing chamber, and the pressurizing chamber can be formed at the upper end of the piston rod with a minimum number of parts. Further, since the pressurizing chamber is provided on the vehicle body side, the suspension device can be mounted even on a vehicle in which it is difficult to provide the pressurizing chamber on the axle side due to the mounting space.

Further, the shock absorber main body has an outer cylinder covering the outer circumference of the cylinder, the housing is mounted on the outer circumference of the outer cylinder, and the movable spring sheet is slidably mounted on both the outer circumference of the outer cylinder and the inner circumference of the housing. May be done. According to the suspension device configured in this way, the provision of the outer cylinder improves the strength and the rigidity against bending and axial load.

According to the suspension device of the present invention, it is small and lightweight even if the vehicle height can be adjusted.

FIG. 1 is a cross-sectional view of the suspension device according to the first embodiment. FIG. 2 is a cross-sectional view of the suspension device according to the first modification of the first embodiment. FIG. 3 is a cross-sectional view of the suspension device according to the second embodiment. FIG. 4 is a cross-sectional view of the suspension device according to the third embodiment.

<First Embodiment>
Hereinafter, the present invention will be described based on the embodiments shown in the figure. As shown in FIG. 1, the suspension device S1 of the first embodiment includes a cylinder 1, a piston 2 movably inserted into the cylinder 1, and an extension chamber R1 partitioned by the piston 2 into the cylinder 1. A single-rod type shock absorber having a compression side chamber R2 and a piston rod 3 connected to a piston 2 movably inserted into the cylinder 1 and allowing liquid to flow in and out of the cylinder 1 during expansion and contraction to exert a damping force. The main body D1, the suspension spring 8 that urges the shock absorber main body D1 in the extension direction, the pressure chamber R3 that is communicated with the compression side chamber R2 and receives the urging force from the suspension spring 8 to pressurize the inside of the cylinder 1, and pressurization. The chamber R3 is provided with a liquid supply / discharge source F capable of supplying / discharging liquid.

In this suspension device S1, the shock absorber main body D1 includes a piston rod 3 that is movably inserted into the cylinder 1 and connected to the piston 2. The other end of the piston rod 3 protrudes outside the cylinder 1, the piston rod 3 is inserted only into the extension side chamber R1, and the shock absorber body D1 is a so-called single rod type shock absorber body. There is. Further, at the tip of the piston rod 3, an annular fixed spring seat 7 is attached to the piston rod 3 in an axially immovable manner, and a mounting shaft 9 is provided so as to be mounted on the vehicle body of a vehicle (not shown). There is. The shape of the fixed spring sheet 7 is not limited to the annular shape, and may be another shape.

A piston 2 is slidably inserted into the cylinder 1, and the inside of the cylinder 1 is divided into an extension side chamber R1 and a compression side chamber R2 by the piston 2. The piston 2 is provided with a damping passage 4 that communicates the extension side chamber R1 and the compression side chamber R2, and the liquid filled in the extension side chamber R1 and the compression side chamber R2 passes through the attenuation passage 4 to the extension side chamber R1 and the compression side chamber R1. It is possible to go back and forth with R2. In the illustrated example, the damping passage 4 allows bidirectional liquid flow and gives resistance to the liquid flow passing through the damping valve 4a provided in the middle, and pressure loss occurs when the liquid passes. Is caused to cause a difference in pressure between the extension side chamber R1 and the compression side chamber R2. The damping valve 4a may be a valve that allows bidirectional flow such as a throttle or a choke, and when a one-way damping valve is adopted, only the flow from the extension side chamber R1 to the compression side chamber R2 is allowed. A damping valve that allows only the flow opposite to the damping valve may be provided in parallel with the damping passage 4. As the liquid filled in the extension side chamber R1 and the compression side chamber R2, a liquid such as water or an aqueous solution can be used in addition to the hydraulic oil.

A tubular housing 5 is provided on the outer periphery of the lower end of FIG. 1 of the cylinder 1, and an annular gap is formed between the cylinder 1 and the housing 5. Further, the housing 5 is attached to the cylinder 1 in a state of being in contact with the flange 1a provided on the outer periphery of the lower end of the cylinder 1, and the lower end opening of the housing 5 is closed.

Further, a cylindrical movable spring seat 6 is slidably mounted on the outer periphery of the cylinder 1. The movable spring seat 6 includes a tubular portion 6a that is in sliding contact with the outer periphery of the cylinder 1 and an annular seat portion 6b provided on the outer periphery of the upper end of the tubular portion 6a. The tubular portion 6a is the outer circumference of the cylinder 1 and a housing. It is in sliding contact with the inner circumference of 5. Therefore, the cylinder portion 6a of the movable spring seat 6 is movably fitted in the annular gap between the housing 5 and the cylinder 1, and the pressurizing chamber R3 is formed in the housing 5. The pressurizing chamber R3 is communicated with the compression side chamber R2 by a through hole 1b provided on the lower side of the cylinder 1, and the pressurizing chamber R3 is filled with a liquid similar to the liquid filled in the cylinder 1. There is. The shape of the sheet portion 6b is not limited to the annular shape, and may be another shape.

Further, a seal ring 6c that is in sliding contact with the outer circumference of the cylinder 1 is provided on the inner circumference of the cylinder portion 6a of the movable spring seat 6, and is slid on the outer circumference of the cylinder portion 6a of the movable spring seat 6 on the inner circumference of the housing 5. A contacting seal ring 5a is provided. Further, a seal ring 5b that is in close contact with the flange 1a of the cylinder 1 is provided at the lower end of the housing 5. The pressurizing chamber R3 is kept liquid-tight by these

seal rings

5a, 5b, and 6c. Instead of providing the flange 1a on the outer circumference of the cylinder 1, an annular bottom may be provided on the inner circumference of the lower end of the housing 5 and the bottom may be fixed to the cylinder 1 by welding or the like. The housing 5 with respect to the cylinder 1 may be provided. The fixed structure of is not limited to the one shown in the figure. Further, instead of providing the seal ring 5a, a seal ring that is in sliding contact with the inner circumference of the housing 5 may be provided on the outer periphery of the tubular portion 6a of the movable spring seat 6.

Although not shown in detail, the movable spring seat 6 may be movably fitted to the outer periphery of the housing 5 to partition the pressurizing chamber R3 between the movable spring seat 6 and the housing 5. Specifically, the cylinder portion 6a of the movable spring seat 6 is slidably contacted with the outer circumference of the housing 5 to be movably fitted, and the inner circumference of the seat portion 6b of the movable spring seat 6 is slidably contacted with the outer circumference of the cylinder 1. The pressure chamber R3 may be formed between the movable spring seat 6 and the housing 5 by being movably fitted.

A coiled suspension spring 8 is interposed between the movable spring seat 6 and the fixed spring seat 7 and on the outer periphery of the shock absorber main body D1, and the shock absorber main body D1 is extended by the suspension spring 8. Being urged in the direction. Further, at the lower end of the cylinder 1, a bracket 10 that can be mounted on the axle of the vehicle described above is provided. Therefore, the suspension device S1 can be mounted between the vehicle body and the axle by using the mounting shaft 9 provided at the upper end of the piston rod 3 and the bracket 10 provided at the lower end of the cylinder 1. When the suspension device S1 is interposed between the vehicle body and the axle in this way, the suspension spring 8 is compressed by the weight of the vehicle body to support and elastically support the vehicle body.

Then, the suspension spring 8 receives a load from the vehicle body and urges the movable spring seat 6 downward in the drawing, and the urging force of the suspension spring 8 is transmitted to the pressurizing chamber R3 via the movable spring seat 6. The pressurizing chamber R3 is pressurized. Since the pressurizing chamber R3 is communicated with the compression side chamber R2 by the through hole 1b provided in the cylinder 1, the extension side chamber R1 and the compression side chamber R2 in the cylinder 1 are similarly pressurized by the urging force of the suspension spring 8. There is.

In the present embodiment, the liquid supply / discharge source F is a tank T for storing liquid, a pipeline H for communicating the tank T with the pressurizing chamber R3, and a constant-capacity pump P provided in the middle of the conduit H. When the pump P is rotated forward by the motor M, the pump 3 sucks the liquid from the tank T and supplies the liquid to the pressurizing chamber R3, and when the pump P is rotated in the reverse direction by the motor M, the pump P is added. The liquid is sucked from the pressure chamber R3 and discharged to the tank T. When the pump P is not driven, the liquid supply / discharge source F cuts off the alternating current of the liquid between the pressurizing chamber R3 and the tank T, and reduces the amount of liquid in the cylinder 1 communicated with the pressurizing chamber R3 and the pressurizing chamber R3. Do not fluctuate. Since the pressurizing chamber R3 and the compression side chamber R2 are communicated with each other, the liquid supply / discharge source F may supply / discharge liquid to the pressurizing chamber R3 via the compression side chamber R2.

When the liquid supply / discharge source F supplies the liquid to the pressurizing chamber R3, the liquid is also supplied to the cylinder 1 communicating with the pressurizing chamber R3. Then, the pressurizing chamber R3 is expanded, the movable spring seat 6 rises in FIG. 1, and the piston rod 3 is pushed away by the volume integral corresponding to the amount of liquid supplied into the cylinder 1, and the piston 2 and the piston rod 3 move. It rises in FIG.

On the other hand, when the liquid supply / discharge source F discharges the liquid from the pressurizing chamber R3, the liquid is also discharged from the cylinder 1 communicating with the pressurizing chamber R3. Then, the pressurizing chamber R3 is reduced, the movable spring seat 6 descends in FIG. 1, and the piston rod 3 invades the cylinder 1 by the volume integral corresponding to the amount of liquid discharged from the cylinder 1, and the piston 2 And the piston rod 3 descends in FIG.

Therefore, the movable spring seat 6 and the piston rod 3 move up and down in FIG. 1 in synchronization with the supply and discharge of the liquid to the pressurizing chamber R3 of the liquid supply / discharge source F, and the vehicle height in the vehicle moves up and down to move the vehicle height. Adjustments are made.

In the case of this embodiment, since the pump P is a constant-capacity pump, the discharge amount per rotation of the pump P is determined, and the lifting amount of the movable spring seat 6 and the piston rod 3 is in the shock absorber main body D1. It is proportional to the amount of liquid supplied to or discharged from the shock absorber body D1. Therefore, since the rotation amount of the pump P is proportional to the lifting amount of the movable spring seat 6 and the piston rod 3, that is, the vehicle height adjustment amount, the vehicle height should be monitored by monitoring the rotation amount of the pump P. Can be done.

If the motor M is equipped with a rotation position sensor, the rotation amount of the pump P may be monitored, and if the motor M does not have the rotation position sensor, the rotation speed of the motor M or the pump P is detected. You may use a sensor that does.

From the above, if the pump P is a fixed-capacity pump, the vehicle height can be grasped from the rotation amount of the pump P, and the vehicle height adjustment becomes very easy. When the pump P is not a constant capacity type, the vehicle height may be grasped by detecting the expansion / contraction displacement of the shock absorber main body D1 and the distance from the road surface of the vehicle body with a sensor.

The pump P may be a piston pump or a gear pump, and the drive source of the pump P may be one that uses the engine power of the vehicle in addition to the motor M. The liquid supply / discharge source F may have a configuration other than the above-described configuration as long as it can supply the liquid into the pressurizing chamber R3 and discharge the liquid from the pressurizing chamber R3. Therefore, for example, it may be configured to include a container provided with a liquid chamber for storing the liquid, a piston movably inserted into the container to change the volume of the liquid chamber, and a drive source for driving the piston. Further, the liquid supply / discharge source F uses the pump P when supplying the liquid to the pressurizing chamber R3, and supplies the liquid to the tank T without going through the pump P when discharging the liquid from the pressurizing chamber R3. A return pipeline may be provided.

As described above, the suspension device S1 is configured, and the operation of the suspension device S1 will be described below. As described above, by the biasing force F _S of the suspension spring 8, the pressure chamber R3 is pressurized. Pressure receiving area (in this case, equal to the cross-sectional area of the cylindrical portion 6a of the movable spring seat 6) of the pressure chamber R3 when the the _{A S,} the pressure _{P C} in the pressurizing chamber R3 _{_{_{is, P C = F S / A}}} S It has become. As described above, since the pressure _CC of the pressurizing chamber R3 is transmitted into the cylinder 1 through the through hole 1b, the pressures of the extension side chamber R1 and the compression side chamber R2 are also equal to the pressure _CC of the pressurization chamber R3. Therefore, when the cross-sectional area of the piston rod 3 and A _R, the vehicle body in the vehicle, the resultant force of the repulsive force A _R × P _C to push the piston rod 3 which is generated by the biasing force F _S and the pressure P _C of the suspension spring 8 is generated Supported by.

When the suspension device S1 is in the extension stroke, the liquid in the extension side chamber R1 compressed by the upward movement of the piston 2 in FIG. 1 passes through the damping passage 4 and the damping valve 4a and is expanded on the compression side. It flows to room R2. Due to the pressure loss when the liquid passes through the damping valve 4a, the pressure in the extension side chamber R1 becomes higher than the pressure in the compression side chamber R2, causing a pressure difference, and the suspension device S1 suppresses the extension in response to this pressure difference. Demonstrates lateral damping force. Further, the volume of the piston rod 3 ejected from the cylinder 1 due to the extension of the suspension device S1 is insufficient in the compression side chamber R2. In contrast, the pressure chamber R3 moves the movable spring seat 6 is pushed downward in FIG. 1 by the biasing force F _S of the suspension spring 8 is compressed, the shortage from the pressure chamber R3 to the compression side chamber R2 The liquid is replenished according to the amount.

When the suspension device S1 is in the process of contracting, the hydraulic oil in the compression side chamber R2 to be compressed is expanded by passing through the damping passage 4 and the damping valve 4a due to the downward movement of the piston 2 in FIG. It flows to the extension chamber R1. Due to the pressure loss when the liquid passes through the damping valve 4a, the pressure in the extension side chamber R1 becomes lower than the pressure in the compression side chamber R2, causing a pressure difference, and the suspension device S1 suppresses contraction in response to this pressure difference. Demonstrates damping force. Further, the volume of the piston rod 3 that invades into the cylinder 1 due to the contraction of the suspension device S1 is pushed out from the cylinder 1 into the pressurizing chamber R3. Due to the inflow of the liquid into the pressurizing chamber R3, the movable spring sheet 6 is pushed upward in FIG. 1, the suspension spring 8 is compressed, the volume of the pressurizing chamber R3 is expanded, and the above-mentioned liquid is discharged by the pressurizing chamber R3. Be absorbed. In this way, the shock absorber main body D1 exerts a damping force by allowing liquid to flow in and out of the cylinder 1 when expanding and contracting.

The amount of expansion and contraction of the suspension spring 8 is not only the stroke amount of the suspension device S1, but also the movement of the movable spring seat 6 due to the change in the push-out volume of the piston rod 3 in the cylinder 1 caused by the displacement of the piston rod 3 with respect to the cylinder 1. The amount is also added. Therefore, when a single spring constant of the suspension spring 8 and K _S, when viewed as a spring exerting a spring force across the vehicle body of the suspension device S1, the spring constant K _E of the spring, K E ₌ K _S ( 1 + _AR / _AS ). In other words, the whole of the suspension device S1 is to function as a spring having a spring constant K _E.

Therefore, since the suspension device S1 can pressurize the inside of the cylinder 1 by the suspension spring 8 and the pressurizing chamber R3 without providing the air chamber in the cylinder 1, the air chamber must be provided in series with the extension side chamber and the compression side chamber. Compared to a suspension device that does not have to be used, the mounting length can be shortened and the mountability on a vehicle is improved.

Next, the operation when the vehicle height is adjusted by the suspension device S1 will be described. When raising the vehicle height, the pump P in the liquid supply / discharge source F is driven in the forward rotation direction to supply the liquid into the pressurizing chamber R3 and the cylinder 1. The liquid is sent into the pressurizing chamber R3 and the cylinder 1, and the movable spring seat 6 is pushed up against the housing 5 by the pressure increase in the pressurizing chamber R3. The push force F1, because equal to a value obtained by multiplying the pressure receiving area _{A S} of the movable spring seat 6 to the pressure _{P C} in the pressurizing chamber R3, the F1 = _{P C} × _{A S.} Further, since the liquid is also sent into the cylinder 1, the pressures in the extension side chamber R1 and the compression side chamber R2 increase, and the piston 2 is pushed up. Since the pressure in the cylinder 1 is equal to the pressure _CC in the pressurizing chamber R3, the force F2 that pushes up the piston 2 is equal to the value obtained by multiplying the pressure in the cylinder 1 by the cross-sectional area of the piston rod 3. = a _{P C} × _{a R.} Therefore, the force F3 of the suspension device S1 is pushed up the vehicle body, since the resultant force of the force F1, F2 to push up the movable spring seat 6 and the piston 2, and _{_{F3 = P C × (A S}} + A R). As described above, in the suspension device S1 of the present embodiment, since the pressurizing chamber R3 and the inside of the cylinder 1 are communicated with each other, it is effective when supplying liquid from the liquid supply / exhaust source F to raise the vehicle height. The pressure receiving area (effective pressure receiving area) is the sum of the pressure receiving area of the movable spring seat 6 and the cross-sectional area of the piston rod 3. Therefore, the suspension device S1 of the present embodiment can secure a large effective pressure receiving area as compared with the conventional suspension device.

As described above, the suspension device S1 of the present embodiment includes the cylinder 1, the piston 2 movably inserted into the cylinder 1, the extension side chamber R1 and the compression side chamber R2 partitioned by the piston 2 into the cylinder 1. A single rod type shock absorber body D1 having a piston rod 3 connected to a piston 2 movably inserted into the cylinder 1 and exerting a damping force by allowing liquid to flow in and out during expansion and contraction, and a shock absorber body. The suspension spring 8 that urges D1 in the extension direction, the pressure chamber R3 that is communicated with the compression side chamber R2 and receives the urging force from the suspension spring 8 to pressurize the inside of the cylinder 1, and the pressure chamber R3 is supplied with liquid. It is equipped with a possible liquid supply / discharge source F. In the suspension device S1 configured in this way, the vehicle height can be adjusted by supplying and discharging the liquid to the pressurizing chamber R3 by the liquid supply / exhaust source F, and the effective pressure receiving area is the pressure receiving area in the pressurizing chamber R3 and the piston rod 3. A large effective pressure receiving area can be secured as the sum of the cross-sectional areas of. Therefore, according to the suspension device S1 configured in this way, it is possible to secure an effective pressure receiving area for adjusting the vehicle height without increasing the pressure receiving area of the pressurizing chamber R3, while avoiding an increase in the size of the pressurizing chamber R3. However, even if the vehicle body weight is heavy, the vehicle height can be adjusted, so even if the vehicle height can be adjusted, the vehicle is compact and lightweight. Further, according to the suspension device S1, since the apparent spring constant can be increased, the spring constant of the suspension spring 8 can be designed to be small, and the suspension spring 8 can be made lighter.

Further, in the suspension device S1 of the present embodiment, since the liquid supply / discharge source F has a constant-capacity pump P, the vehicle height can be adjusted to a target vehicle height only by managing the rotation amount of the pump P. Since it can be done, the vehicle height can be easily adjusted.

Further, in the suspension device S1 of the present embodiment, since the inside of the cylinder 1 can be pressurized by the suspension spring 8 and the pressurizing chamber R3 without providing the air chamber in the cylinder 1, the air chamber is connected in series with the extension side chamber and the compression side chamber. Compared to the suspension device that must be installed in the vehicle, the mounting length can be shortened, the mountability on the vehicle is improved, and the number of parts is reduced.

Further, in the suspension device S1 of the present invention, instead of pressurizing the inside of the cylinder 1 in the air chamber, the inside of the cylinder 1 is pressurized by the suspension spring 8 and the pressurizing chamber R3. In the suspension device that pressurizes the inside of the cylinder 1 with gas, there is a problem that the pressure fluctuates due to the temperature change of the gas and the vehicle height fluctuates. However, in the suspension device S1 of the present invention, such pressure fluctuation does not occur. , There is no problem that the vehicle height changes.

Further, in the suspension device that pressurizes the inside of the cylinder 1 with gas, the pressure in the air chamber may decrease after being used for a long period of time. High reliability can be ensured without the problem that the vehicle height fluctuates and the damping force characteristics do not change even after long-term use.

Further, since the suspension device S1 can pressurize the inside of the cylinder 1 by the suspension spring 8 and the pressurizing chamber R3 without providing an air chamber in the cylinder 1, the volume elastic modulus of the liquid can be secured and the damping force can be responsively applied. Can be demonstrated. Further, in the case of a suspension device in which an air chamber is provided in the shock absorber body to form a gas spring, the gas spring reaction force increases remarkably as the amount of compression of the shock absorber body increases, so that the spring constant of the entire suspension device is displaced. It becomes non-linear with respect to. On the other hand, since the gas spring is not formed in the shock absorber main body D1 of this example, the spring constant does not become non-linear with respect to the displacement when the entire suspension device S1 is viewed as a spring, and the riding comfort in the vehicle is also improved. To do.

Further, in the suspension device S1 of this example, the pressurizing chamber R3 is movably fitted to the hollow housing 5 and the housing 5, and is partitioned by the movable spring seat 6 urged by the suspension spring 8. It is easy to install the pressurizing chamber R3 in the shock absorber body D1.

Further, in the suspension device S1 of this example, the housing 5 is mounted on the outer circumference of the cylinder 1, and the movable spring seat 6 is slidably mounted on both the outer circumference of the cylinder 1 and the inner circumference of the housing 5. When the suspension device S1 is configured in this way, the cylinder 1 can be used as a forming component of the pressurizing chamber R3, the pressurizing chamber R3 can be formed on the outer periphery of the cylinder 1 with the minimum number of parts, and the outer diameter of the reservoir is on the outer periphery of the cylinder. It only needs to have a double-cylinder shock absorber, and can be easily installed in a vehicle.

As in the suspension device S1a shown in FIG. 2, a valve case 11 is provided at the lower end of the cylinder 1, and the valve case 11 is damped on the pressure side to give resistance to the flow of liquid from the pressure side chamber R2 to the pressure chamber R3. The pressurizing chamber R3 may be used as a reservoir by providing a passage 11a and a suction valve 11b that allows only the flow of liquid from the pressurizing chamber R3 to the compression side chamber R2. When the suspension device S1a configured in this way is in the process of extension, the liquid in the extension side chamber R1 to be compressed flows to the compression side chamber R2 which is expanded through the damping passage 4 and the damping valve 4a. Due to the pressure loss when the liquid passes through the damping valve 4a, the pressure in the extension side chamber R1 becomes higher than the pressure in the compression side chamber R2 to cause a pressure difference, and the suspension device S1a suppresses the extension in response to this pressure difference. Demonstrates lateral damping force. Further, the volume of the piston rod 3 ejected from the cylinder 1 due to the extension of the suspension device S1 is insufficient in the compression side chamber R2, but the suspension spring 8 pushes the movable spring seat 6 downward in FIG. R3 is compressed, and the insufficient liquid is replenished from the pressurizing chamber R3 to the compression side chamber R2 via the suction valve 11b.

When the suspension device S1a is in the process of contracting, the hydraulic oil in the compression side chamber R2 to be compressed is expanded by passing through the damping passage 4 and the damping valve 4a due to the downward movement of the piston 2 in FIG. It flows to the extension side chamber R1. Further, the liquid corresponding to the volume of the piston rod 3 that enters the cylinder 1 due to the contraction of the suspension device S1a is discharged from the cylinder 1 to the pressurizing chamber R3 via the compression side damping passage 11a. Due to the pressure loss when the liquid passes through the damping valve 4a and the compression side damping passage 11a, the pressure in the extension side chamber R1 becomes lower than the pressure in the compression side chamber R2, causing a pressure difference, and the suspension device S1a responds to this pressure difference. It exerts a compression side damping force that suppresses contraction. Due to the inflow of the liquid into the pressurizing chamber R3, the movable spring sheet 6 is pushed upward in FIG. 2, the suspension spring 8 is compressed, the volume of the pressurizing chamber R3 is expanded, and the above-mentioned liquid is discharged by the pressurizing chamber R3. Be absorbed.

Further, even in the suspension device S1a configured in this way, if the liquid is supplied from the liquid supply / discharge source F to the pressurizing chamber R3, the liquid is supplied to the pressurizing chamber R3 and the cylinder 1 to raise the vehicle height. If the liquid is discharged from the pressurizing chamber R3 at the liquid supply / discharge source F, the vehicle height can be lowered. The suspension device S1a configured in this way can secure a large effective pressure receiving area (effective pressure receiving area) as the sum of the pressure receiving area in the pressure chamber R3 and the cross-sectional area of the piston rod 3 when adjusting the vehicle height. Therefore, even if the vehicle height can be adjusted, it is compact and lightweight.

<Second embodiment>
In the suspension device S2 of the second embodiment, as shown in FIG. 3, the pressurizing chamber R3 is provided on the outer periphery of the cylinder 1 of the shock absorber main body D1 in the suspension device S1 of the first embodiment. Therefore, it differs from the suspension device S1 in that a pressurizing chamber R3 is provided on the outer periphery of the piston rod 3 of the shock absorber main body D2.

Therefore, in the suspension device S1 of the first embodiment, the housing 5 is provided on the outer periphery of the cylinder 1, but in the suspension device S2 of the second embodiment, the tubular housing is provided on the upper outer periphery of the piston rod 3. 12 is provided.

Further, in the suspension device S1 of the first embodiment, the movable spring seat 6 is mounted on the outer periphery of the cylinder 1, but in the suspension device S2 of the second embodiment, the movable spring seat 6 is movable on the upper outer periphery of the piston rod 3. The spring seat 13 is attached.

Hereinafter, the parts of the suspension device S2 of the second embodiment different from those of the suspension device S1 of the first embodiment will be described in detail, and in order to avoid duplication of description, the same members are designated by the same reference numerals. A detailed description will be omitted.

The housing 12 has a tubular shape, and in this example, it is attached to the outer periphery of the upper end of the piston rod 3. Specifically, the housing 12 is provided with an annular mounting portion 12a on the inner circumference of the upper end, and the mounting portion 12a is mounted on the outer periphery of the piston rod 3. When the housing 12 is attached to the piston rod 3 in this way, an annular gap is formed between the housing 12 and the piston rod 3.

The movable spring seat 13 is slidably mounted on the outer circumference of the piston rod 3. The movable spring seat 13 includes an inner cylinder 13a that is in sliding contact with the outer circumference of the piston rod 3, an outer cylinder 13b provided on the outer circumference of the inner cylinder 13a, and a flange portion 13c that connects the lower end of the inner cylinder 13a and the lower end of the outer cylinder 13b. The outer cylinder 13b is provided with an annular seat portion 13d provided on the outer periphery of the upper end. The shape of the sheet portion 13d is not limited to the annular shape, and may be another shape.

Then, the inner cylinder 13a is slidably contacted with the outer circumference of the piston rod 3 and the inner circumference of the housing 12 to be movably fitted into the annular gap, the annular gap is closed, and the space between the piston rod 3 and the housing 12 is closed. A pressurizing chamber R3 is formed. Further, a seal ring 13e that slides into the outer circumference of the piston rod 3 is provided on the inner circumference of the inner cylinder 13a, and a seal ring 13f that slides into the inner circumference of the housing 12 is provided on the outer circumference of the inner cylinder 13a. .. Further, a seal ring 12b that is in close contact with the outer circumference of the piston rod 3 is provided on the inner circumference of the mounting portion 12a of the housing 12. The pressure chamber R3 is maintained in a liquid-tight state by the seal rings 12b, 13e, and 13f. Further, the pressurizing chamber R3 is communicated with the compression side chamber R2 via a passage 3a provided in the piston rod 3.

Although not shown in detail, the movable spring seat 13 may be movably fitted to the outer periphery of the housing 12 to partition the pressurizing chamber R3 between the movable spring seat 13 and the housing 12. Specifically, the inner cylinder 13a of the movable spring seat 13 is eliminated, the outer cylinder 13b is slidably contacted with the outer circumference of the housing 12 to be movably fitted, and the inner circumference of the flange portion 13c of the movable spring seat 13 is pistoned. The pressure chamber R3 may be formed between the movable spring seat 13 and the housing 12 by sliding contact with the outer periphery of the rod 3 and fitting the rod 3 so as to be movable.

Further, the liquid supply / discharge source F is configured to include a conduit H for communicating the pressurizing chamber R3 in the housing 12 and the tank T, and a pump P provided in the middle of the conduit H, and the pressurizing chamber R3. Supply and discharge liquid to the housing. The liquid supply / discharge source F may supply / discharge liquid to the pressurizing chamber R3 via the compression side chamber R2 by connecting the pipeline H to the compression side chamber R2.

The configuration of the shock absorber main body D2 in the suspension device S2 of the second embodiment is the first except that the piston rod 3 is provided with the passage 3a and the through hole 1b in the cylinder 1 is abolished. This is the same as the shock absorber main body D1 in the suspension device S1.

An annular fixed spring seat 14 is attached to the outer periphery of the cylinder 1 in the suspension device S2 of the second embodiment instead of the housing 5 and the movable spring seat 6. The shape of the fixed spring sheet 14 is not limited to the annular shape, and may be another shape.

A coiled suspension spring 8 is interposed between the movable spring seat 13 and the fixed spring seat 14 and on the outer periphery of the shock absorber main body D2, and the shock absorber main body D2 is extended by the suspension spring 8. Being urged in the direction. Therefore, when the suspension device S2 is interposed between the vehicle body and the axle, the suspension spring 8 is compressed by the weight of the vehicle body to support and elastically support the vehicle body.

Then, the suspension spring 8 receives a load from the vehicle body and urges the movable spring seat 13 upward in the drawing, and the urging force of the suspension spring 8 is transmitted to the pressurizing chamber R3 via the movable spring seat 13. The pressurizing chamber R3 is pressurized. Since the pressurizing chamber R3 is communicated with the compression side chamber R2 by the passage 3a provided in the piston rod 3, the extension side chamber R1 and the compression side chamber R2 in the cylinder 1 are similarly pressurized by the urging force of the suspension spring 8. There is. Therefore, even in the suspension device S2 of the second embodiment, the cylinder 1 is provided by the suspension spring 8 and the pressurizing chamber R3 without providing an air chamber, as in the suspension device S1 of the first embodiment. The inside can be pressurized.

As described above, the suspension device S2 is configured, and the pressurizing chamber R3 is communicated with the compression side chamber R2. Therefore, as in the suspension device S1 of the first embodiment, the pressure in the cylinder 1 is increased. It becomes equal to the pressure _CC of the pressurizing chamber R3. Therefore, when the cross-sectional area of the piston rod 3 and A _R, suspension system S2 is like the suspension system S1 of the first embodiment, the piston rod produced by the biasing force F _S and the pressure P _C of the suspension springs 8 3 support body by the resultant force of the repulsive force a _R × P _C to boost.

When the suspension device S2 is in the extending stroke, the liquid in the extension side chamber R1 compressed by the upward movement of the piston 2 in FIG. 3 passes through the damping passage 4 and the damping valve 4a and is expanded on the compression side. It flows to room R2. Due to the pressure loss when the liquid passes through the damping valve 4a, the pressure in the extension side chamber R1 becomes higher than the pressure in the compression side chamber R2, causing a pressure difference, and the suspension device S2 suppresses the extension in response to this pressure difference. Demonstrates lateral damping force. Further, the compression side chamber R2 lacks the amount of liquid corresponding to the volume of the piston rod 3 that exits from the cylinder 1 due to the extension of the suspension device S2. In contrast, the pressure chamber R3 moves the movable spring seat 13 is pushed upward in FIG. 3 by the biasing force F _S of the suspension spring 8 is compressed, the shortage from the pressure chamber R3 to the compression side chamber R2 The liquid is replenished according to the amount.

When the suspension device S2 is in the process of contracting, the hydraulic oil in the compression side chamber R2 to be compressed is expanded by passing through the damping passage 4 and the damping valve 4a due to the downward movement of the piston 2 in FIG. It flows to the extension side chamber R1. Due to the pressure loss when the liquid passes through the damping valve 4a, the pressure in the extension side chamber R1 becomes lower than the pressure in the compression side chamber R2, causing a pressure difference, and the suspension device S2 suppresses contraction in response to this pressure difference. Demonstrates damping force. Further, the volume of the piston rod 3 that invades into the cylinder 1 due to the contraction of the suspension device S2 is pushed out from the cylinder 1 into the pressurizing chamber R3. Due to the inflow of the liquid into the pressurizing chamber R3, the movable spring seat 13 is pushed downward in FIG. 3, the suspension spring 8 is compressed, the volume of the pressurizing chamber R3 is expanded, and the above-mentioned liquid is discharged by the pressurizing chamber R3. Be absorbed.

As described above, the amount of expansion and contraction of the suspension spring 8 is not only the stroke amount of the suspension device S2, but also the change in the pushing volume of the piston rod 3 in the cylinder 1 caused by the displacement of the piston rod 3 with respect to the cylinder 1. The amount of movement is also added. Accordingly, the pressure receiving area of the pressure chamber R3 A _S, when a single spring constant of the suspension spring 8 and K _S, when viewed as a spring for applying a spring force to the whole of the suspension apparatus S2 to the vehicle body, the spring of the spring constant _{K E} _is a _{_{K E = K S (1 +}} a R / a S). In other words, the whole of the suspension device S2 is like the suspension system S1 of the first embodiment, functions as a spring having a spring constant K _E.

Therefore, since the suspension device S2 can pressurize the inside of the cylinder 1 by the suspension spring 8 and the pressurizing chamber R3 without providing the air chamber, the suspension device S2 must provide the air chamber in series with the extension side chamber and the compression side chamber. In comparison, the mounting length can be shortened and the mountability on the vehicle is improved.

Then, when the vehicle height is raised by the suspension device S2, the pump P in the liquid supply / discharge source F is driven in the forward rotation direction to supply the liquid into the pressurizing chamber R3 and the cylinder 1. The liquid is sent into the pressurizing chamber R3 and the cylinder 1, and the movable spring seat 13 is pushed down against the housing 12 by the pressure increase in the pressurizing chamber R3. The depressing force F1, because equal to a value obtained by multiplying the pressure receiving area _{A S} of the movable spring seat 13 to the pressure _{P C} in the pressurizing chamber R3, the F1 = _{P C} × _{A S.} Further, since the liquid is also sent into the cylinder 1, the pressures in the extension side chamber R1 and the compression side chamber R2 increase, and the piston 2 is pushed up. Since the pressure in the cylinder 1 is equal to the pressure _CC in the pressurizing chamber R3, the force F2 that pushes up the piston 2 is equal to the value obtained by multiplying the pressure in the cylinder 1 by the cross-sectional area of the piston rod 3. = a _{P C} × _{a R.}

Since the force F1 that pushes down the movable spring seat 13 acts as a reaction that pushes up the housing 12 in FIG. 3, the force F3 that pushes up the vehicle body by the suspension device S2 becomes the resultant force of the forces F1 and F2 that push up the housing 12 and the piston 2. , the _{_{F3 = P C × (a S}} + a R). As described above, even in the suspension device S2 of the present embodiment, since the pressurizing chamber R3 and the inside of the cylinder 1 are communicated with each other, when the liquid is supplied from the liquid supply / discharge source F to raise the vehicle height. The effective pressure receiving area (effective pressure receiving area) is the sum of the pressure receiving area of the movable spring seat 13 and the cross-sectional area of the piston rod 3. Therefore, according to the suspension device S2 of the present embodiment, a large effective pressure receiving area can be secured as compared with the conventional suspension device.

Like the suspension device S2 of the present embodiment, the housing 12 is attached to the piston rod 3, and the movable spring seat 13 is slidably attached to both the outer circumference of the piston rod 3 and the inner circumference of the housing 12 to be applied. Even if the compression chamber R3 and the compression side chamber R2 are communicated with each other by the passage 3a provided in the piston rod 3, the vehicle height can be adjusted by supplying and discharging the liquid from the liquid supply / discharge source F to the pressure chamber R3. Further, in the suspension device S2 configured as described above, since the effective pressure receiving area is the sum of the pressure receiving area in the pressurizing chamber R3 and the cross section of the piston rod 3, a large effective pressure receiving area can be secured. Therefore, according to the suspension device S2 configured in this way, it is possible to secure an effective pressure receiving area for adjusting the vehicle height without increasing the pressure receiving area of the pressurizing chamber R3, while avoiding an increase in the size of the pressurizing chamber R3. However, even if the vehicle body weight is heavy, the vehicle height can be adjusted, so even if the vehicle height can be adjusted, the vehicle is compact and lightweight. Further, according to the suspension device S2, since the apparent spring constant can be increased, the spring constant of the suspension spring 8 can be designed to be small, and the suspension spring 8 can be made lighter.

Further, in the suspension device S2 of the present embodiment, since the inside of the cylinder 1 can be pressurized by the suspension spring 8 and the pressurizing chamber R3 without providing the air chamber in the cylinder 1, the air chamber is connected in series with the extension side chamber and the compression side chamber. Compared to the suspension device that must be installed in the vehicle, the mounting length can be shortened, the mountability on the vehicle is improved, and the number of parts is reduced.

Further, in the suspension device S2 of the present invention, instead of pressurizing the inside of the cylinder 1 in the air chamber, the inside of the cylinder 1 is pressurized by the suspension spring 8 and the pressurizing chamber R3. Therefore, the suspension device S2 of the second embodiment does not cause a problem that the vehicle height changes like the suspension device S1 of the first embodiment, and the damping force characteristic changes even after long-term use. High reliability can be ensured without doing so. Further, the suspension device S2 can secure the volume elastic modulus of the liquid, can exert a damping force with good responsiveness, and when the entire suspension device S2 is viewed as a spring, the spring constant does not become non-linear with respect to the displacement, and the vehicle rides on the vehicle. It also improves comfort.

In the suspension device S2 of this example, the housing 12 is attached to the piston rod 3 in the shock absorber main body D2, and the movable spring seat 13 is slidably attached to both the outer circumference of the piston rod 3 and the inner circumference of the housing 12. When the suspension device S2 is configured in this way, the piston rod 3 can be used as a forming component of the pressurizing chamber R3, and the pressurizing chamber R3 can be formed at the upper end of the piston rod 3 with a minimum number of parts. Further, since the pressurizing chamber R3 is provided on the vehicle body side, if it is difficult to mount the suspension device S1 having the pressurizing chamber R3 on the axle side due to the mounting space, the structure of the suspension device S2 is adopted and mounted on the vehicle. it can. On the contrary, when it is difficult to mount the suspension device S2 having the pressurizing chamber R3 on the vehicle body side due to the mounting space, the structure of the suspension device S1 may be adopted and mounted on the vehicle.

<Third embodiment>
As shown in FIG. 4, in the suspension device S3 of the third embodiment, in the shock absorber main body D1 of the suspension device S1 of the first embodiment, a housing 5 is provided on the outer periphery of the cylinder 1 to provide a movable spring seat 6. While the pressurizing chamber R3 is provided by sliding contact, the shock absorber main body D3 is provided with an outer cylinder 15 covering the outer periphery of the cylinder 1 and a pressurizing chamber R3 is provided on the outer periphery of the outer cylinder 15. It is different from S1.

Therefore, in the suspension device S1 of the first embodiment, the housing 5 is provided on the outer periphery of the cylinder 1, but in the suspension device S3 of the third embodiment, the outer circumference of the outer cylinder 15 covering the outer periphery of the cylinder 1 is provided. Is provided with a tubular housing 16.

Further, in the suspension device S1 of the first embodiment, the movable spring seat 6 is mounted on the outer periphery of the cylinder 1, but in the suspension device S3 of the third embodiment, the movable spring is attached to the outer periphery of the outer cylinder 15. The seat 17 is attached.

Hereinafter, the parts of the suspension device S3 of the third embodiment that differ from the suspension device S1 of the first embodiment will be described in detail, and the same members will be designated by the same reference numerals in order to avoid duplication of description. A detailed description will be omitted.

The shock absorber main body D3 in the suspension device S3 of the third embodiment has a structure in which an outer cylinder 15 covering the cylinder 1 is provided on the outer periphery of the cylinder 1 of the shock absorber main body D1 in the suspension device S1 of the first embodiment. It has become. The annular gap G between the cylinder 1 and the outer cylinder 15 is communicated with the compression side chamber R2 through a through hole 1b provided in the cylinder 1 and is filled with a liquid.

Further, the housing 16 provided on the outer periphery of the outer cylinder 15 is attached in a state of being in contact with the flange 15a provided on the outer periphery of the lower end of the outer cylinder 15, and the lower end opening of the housing 16 is closed.

Further, a tubular movable spring sheet 17 is slidably mounted on the outer circumference of the outer cylinder 15. The movable spring sheet 17 includes a tubular portion 17a that is in sliding contact with the outer periphery of the outer cylinder 15 and an annular seat portion 17b provided on the outer periphery of the upper end of the tubular portion 17a. The tubular portion 17a is the outer circumference of the outer cylinder 15. Is in sliding contact with the inner circumference of the housing 16. Therefore, the tubular portion 17a of the movable spring seat 17 is movably fitted in the annular gap between the housing 16 and the outer cylinder 15, and the pressurizing chamber R3 is formed in the housing 16. The pressurizing chamber R3 is communicated with the compression side chamber R2 via a through hole 15b, an annular gap G and a through hole 1b provided on the lower side of the outer cylinder 15, and the pressurizing chamber R3 is filled in the cylinder 1. It is filled with a liquid similar to the liquid to be used. The shape of the sheet portion 17b is not limited to the annular shape, and may be another shape.

Further, the space between the movable spring seat 17 and the housing 16, the space between the outer cylinder 15 and the housing 16, and the space between the movable spring seat 17 and the outer cylinder 15 are sealed by

seal rings

16a, 16b, and 17c, respectively. The pressurizing chamber R3 is kept liquidtight. Instead of providing the flange 15a on the outer circumference of the outer cylinder 15, an annular bottom may be provided on the inner circumference of the lower end of the housing 16 and the bottom may be fixed to the outer cylinder 15 by welding or the like. The fixed structure of the housing 16 with respect to the housing 16 is not limited to that shown in the figure. Further, instead of providing the seal ring 16a, a seal ring that is in sliding contact with the inner circumference of the housing 16 may be provided on the outer periphery of the tubular portion 17a of the movable spring seat 17.

Further, the liquid supply / discharge source F is configured to include a conduit H for communicating the pressurizing chamber R3 in the housing 16 and the tank T, and a pump P provided in the middle of the conduit H, and the pressurizing chamber R3. Supply and discharge liquid to the housing. The liquid supply / discharge source F connects the pipeline H to the annular gap G or the compression side chamber R2, and supplies / discharges the liquid to the pressurizing chamber R3 via the annular gap G or the annular gap G and the compression side chamber R2. May be good.

A suspension spring 8 is interposed between the movable spring seat 17 and the fixed spring seat 7 on the outer periphery of the shock absorber body D3, and the suspension spring 8 urges the shock absorber body D3 in the extension direction. At the same time, the pressurizing chamber R3 is pressurized via the movable spring sheet 17. Since the pressurizing chamber R3 is communicated with the compression side chamber R2 by the through hole 1b provided in the cylinder 1, the extension side chamber R1 and the compression side chamber R2 in the cylinder 1 are similarly pressurized by the urging force of the suspension spring 8. There is. Therefore, even in the suspension device S3 of the third embodiment, the cylinder 1 is provided by the suspension spring 8 and the pressurizing chamber R3 without providing an air chamber, as in the suspension device S1 of the first embodiment. The inside can be pressurized.

As described above, the suspension device S3 is configured, and the pressurizing chamber R3 is communicated with the compression side chamber R2. Therefore, as in the suspension device S1 of the first embodiment, the pressure in the cylinder 1 is increased. It becomes equal to the pressure _CC of the pressurizing chamber R3. Therefore, when the cross-sectional area of the piston rod 3 and A _R, the suspension device S3 is like the suspension system S1 of the first embodiment, the piston rod produced by the biasing force F _S and the pressure P _C of the suspension springs 8 3 support body by the resultant force of the repulsive force a _R × P _C to boost.

As described above, the suspension device S3 has the same structure as the suspension device S1 except that the pressurizing chamber R3 and the compression side chamber R2 are communicated with each other through the annular gap G. Therefore, the suspension device S3 operates in the same manner as the suspension device S1 and exerts a damping force during expansion and contraction. Further, when a single spring constant of the suspension spring 8 and K _S, when viewed as a spring exerting a spring force across the vehicle body of the suspension device S3, the spring constant K _E of the spring, K E ₌ K _S ( 1 + _AR / _AS ). In other words, the whole of the suspension device S3 is functions as a spring having a spring constant K _E.

Therefore, since the suspension device S3 can pressurize the inside of the cylinder 1 by the suspension spring 8 and the pressurizing chamber R3 without providing the air chamber in the cylinder 1, the air chamber must be provided in series with the extension side chamber and the compression side chamber. Compared to a suspension device that does not have to be used, the mounting length can be shortened and the mountability on a vehicle is improved.

Then, when the vehicle height is raised by the suspension device S3, the pump P in the liquid supply / discharge source F is driven in the forward rotation direction to supply the liquid into the pressurizing chamber R3 and the cylinder 1. The liquid is sent into the pressurizing chamber R3 and the cylinder 1, and the movable spring seat 17 is pushed up with respect to the housing 16 by the pressure increase in the pressurizing chamber R3. The push force F1, because equal to a value obtained by multiplying the pressure receiving area _{A S} of the movable spring seat 17 to the pressure _{P C} in the pressurizing chamber R3, the F1 = _{P C} × _{A S.} Further, since the liquid is also sent into the cylinder 1, the pressures in the extension side chamber R1 and the compression side chamber R2 increase, and the piston 2 is pushed up. Since the pressure in the cylinder 1 is equal to the pressure _CC in the pressurizing chamber R3, the force F2 that pushes up the piston 2 is equal to the value obtained by multiplying the pressure in the cylinder 1 by the cross-sectional area of the piston rod 3. = a _{P C} × _{a R.} Therefore, the force F3 of the suspension device S3 is pushing up the vehicle body, since the resultant force of the force F1, F2 to push up the movable spring seat 17 and the piston 2, and _{_{F3 = P C × (A S}} + A R).

As described above, even in the suspension device S3 of the present embodiment, since the pressurizing chamber R3 and the inside of the cylinder 1 are communicated with each other, when the liquid is supplied from the liquid supply / discharge source F to raise the vehicle height. The effective pressure receiving area (effective pressure receiving area) is the sum of the pressure receiving area of the movable spring seat 17 and the cross-sectional area of the piston rod 3. Therefore, according to the suspension device S3 of the present embodiment, a large effective pressure receiving area can be secured as compared with the conventional suspension device.

Like the suspension device S3 of the present embodiment, the outer cylinder 15 is provided on the outer circumference of the cylinder 1, the housing 16 is provided on the outer circumference of the outer cylinder 15, and the movable spring seat 17 is provided on the outer circumference of the outer cylinder 15 and the housing 16. Even if the pressurizing chamber R3 is provided so as to be slidably mounted on both sides, the vehicle height can be adjusted by supplying and discharging the liquid from the liquid supply / discharge source F to the pressurizing chamber R3. Further, in the suspension device S3 configured in this way, the effective pressure receiving area (effective pressure receiving area) at the time of adjusting the vehicle height is the sum of the pressure receiving area in the pressure chamber R3 and the cross-sectional area of the piston rod 3 to increase the effective pressure receiving area. Can be secured. Therefore, according to the suspension device S3 configured in this way, it is possible to secure an effective pressure receiving area for adjusting the vehicle height without increasing the pressure receiving area of the pressurizing chamber R3, while avoiding an increase in the size of the pressurizing chamber R3. However, even if the vehicle body weight is heavy, the vehicle height can be adjusted, so even if the vehicle height can be adjusted, the vehicle is compact and lightweight. Further, according to the suspension device S3, since the apparent spring constant can be increased, the spring constant of the suspension spring 8 can be designed to be small, and the suspension spring 8 can be made lighter.

Further, in the suspension device S3 of the present embodiment, since the inside of the cylinder 1 can be pressurized by the suspension spring 8 and the pressurizing chamber R3 without providing the air chamber in the cylinder 1, the air chamber is connected in series with the extension side chamber and the compression side chamber. Compared to the suspension device that must be installed in the vehicle, the mounting length can be shortened and the mountability on the vehicle is improved. Further, since the outer cylinder 15 covers the outer periphery of the cylinder 1 and the shock absorber main body D3 has a double pipe structure, the strength can be improved and the bending and the rigidity in the axial direction can be increased.

Further, in the suspension device S3 of the present invention, instead of pressurizing the inside of the cylinder 1 in the air chamber, the inside of the cylinder 1 is pressurized by the suspension spring 8 and the pressurizing chamber R3. Therefore, the suspension device S3 of the third embodiment does not cause a problem that the vehicle height changes like the suspension device S1 of the first embodiment, and the damping force characteristic changes even after long-term use. High reliability can be ensured without doing so. Further, the suspension device S3 can secure the volume elastic modulus of the liquid, can exert a damping force with good responsiveness, and when the entire suspension device S3 is viewed as a spring, the spring constant does not become non-linear with respect to the displacement, and the vehicle rides on the vehicle. It also improves comfort.

Although the preferred embodiments of the present invention have been described in detail above, they can be modified, modified, and modified as long as they do not deviate from the claims.

1 ... Cylinder, 2 ... Piston, 3 ... Piston rod, 5,12,16 ... Housing, 6,13,17 ... Movable spring seat, 8 ... Suspension spring, 15. .. outer cylinder, D1, D2, D3 ... shock absorber body, F ... liquid supply / discharge source, P ... pump, S1, S1a, S2, S3 ... suspension device, R1 ... extension Side chamber, R2 ... compression side chamber, R3 ... pressurization chamber

Claims

Suspension device
A cylinder, a piston movably inserted into the cylinder, an extension chamber and a compression side chamber partitioned by the piston in the cylinder, and a piston rod connected to the piston movably inserted into the cylinder. A shock absorber body that exerts a damping force by allowing liquid to enter and exit the cylinder during expansion and contraction.
A suspension spring that urges the shock absorber body in the extension direction,
A pressurizing chamber that communicates with the compression side chamber and receives urging force from the suspension spring to pressurize the inside of the cylinder.
A suspension device provided with a liquid supply / discharge source capable of supplying / discharging liquid to the pressurizing chamber.
The suspension device according to claim 1.
The liquid supply / discharge source is a suspension device having a constant-capacity pump.
The suspension device according to claim 1.
A suspension device in which the pressurizing chamber is partitioned by a hollow housing and a movable spring seat that is movably fitted to the housing and urged by the suspension spring.
The suspension device according to claim 3.
The housing is mounted on the outer circumference of the cylinder.
The movable spring seat is a suspension device that is slidably mounted on both the outer circumference of the cylinder and the inner circumference of the housing.
The suspension device according to claim 3.
The housing is attached to the piston rod and
The movable spring seat is slidably mounted on both the outer circumference of the piston rod and the inner circumference of the housing.
A suspension device in which the pressurizing chamber and the compression side chamber are communicated with each other by a passage provided in the piston rod.
The suspension device according to claim 3.
The shock absorber body has an outer cylinder that covers the outer circumference of the cylinder.
The housing is mounted on the outer circumference of the outer cylinder.
The movable spring seat is a suspension device that is slidably mounted on both the outer circumference of the outer cylinder and the inner circumference of the housing.