Suspension device

Abstract

To suppress a suspension device from being bulky.SOLUTION: A suspension device comprises: a double cylindrical upper base 11; a double cylindrical lower base 12; an inner member 13 connected to an upper end part of a rod 52 of a damper 51; a first elastic body 14 and a second elastic body 15 that independently connect inner cylinders 21, 25 included respectively in the upper base and the lower base, to the inner member; a third elastic body 16 that connects outer cylinders 22, 26 included respectively in the upper base and the lower base, to each other; and a supply / discharge mechanism 17 which supplies / discharges pressurized air to / from an air chamber X surrounded by the upper base, the lower base, the first elastic body, the second elastic body, and the third elastic body. In association with the supply / discharge of pressurized air to / from the air chamber, the first elastic body, the second elastic body, and the third elastic body expand and contract while elastically deforming, to move the upper base and the lower base relatively in a vertical direction. When the supply / discharge mechanism discharges the pressurized air from the air chamber, the upper base and the lower base relative approach in the vertical direction while the first elastic body, the second elastic body, and the third elastic body are compressively deformed.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a suspension system. [Background technology]

[0002] Conventionally, as shown in, for example, FIG. 4 of Patent Document 1 below, there has been known a suspension system that includes an upper base (41a) connected to the vehicle body, a lower base (16) provided below the upper base, an inner member (26, 43) provided between the upper base and the lower base and connected to the upper end of a damper rod (3a), an elastic body (41) connecting the upper base and the inner member to each other, an elastic membrane (17) provided below the lower base, and a supply and exhaust mechanism that supplies and exhausts pressurized air into the elastic membrane, and that is capable of adjusting the vehicle height by supplying and exhausting pressurized air into the elastic membrane to expand and contract the elastic membrane. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2004-314840 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, the conventional suspension system has a problem in that it is difficult to suppress the bulkiness.

[0005] The present invention has been made in consideration of the above circumstances, and has an object to provide a suspension device that can reduce bulk. [Means for solving the problem]

[0006] In order to solve the above problems and achieve the above object, a suspension device of the present invention includes a double-cylindrical upper base connected to a vehicle body, a double-cylindrical lower base that is disposed below the upper base so as to be movable upward relative to the upper base and that supports an upper end of a coil spring, an inner member that is disposed radially inward from the inner cylinders of the upper base and the lower base and that is connected to an upper end of a rod of a damper, a first elastic body and a second elastic body that respectively connect the inner cylinders of the upper base and the lower base and the inner member, and a spring that connects the upper base and the lower base to each other. The device is equipped with a third elastic body that connects each of the outer tubes to each other, and a supply and exhaust mechanism that supplies and exhausts pressurized air to an air chamber surrounded by the upper base, the lower base, the first elastic body, the second elastic body, and the third elastic body, and as the pressurized air is supplied and exhausted, the air chamber expands and contracts while the first elastic body, the second elastic body, and the third elastic body elastically deform, and the upper base and the lower base move relatively in the vertical direction, and when the pressurized air is exhausted from the air chamber by the supply and exhaust mechanism, the first elastic body, the second elastic body, and the third elastic body are compressed and deformed, and the upper base and the lower base move closer to each other in the vertical direction.

[0007] When vibrations are input with pressurized air being supplied to the air chamber by the supply and discharge mechanism, not only the coil spring but also the first elastic body, the second elastic body, and the third elastic body elastically deform, causing the upper base and the lower base to relatively displace, and the damping force of the damper is reduced by being propagated through the first elastic body, the second elastic body, and the third elastic body via the inner member and reaches the vehicle body. As a result, by supplying pressurized air to the air chamber during normal vehicle driving, a comfortable ride can be ensured. When the pressurized air is exhausted from the air chamber by the supply and exhaust mechanism, the first elastic body, the second elastic body, and the third elastic body undergo compressive deformation while the upper base and the lower base move relatively closer to each other in the vertical direction, so that the springs of the first elastic body, the second elastic body, and the third elastic body become taller. As a result, when the vehicle is traveling at high speed, by evacuating the pressurized air from the air chamber, the springs of the first elastic body, the second elastic body, and the third elastic body become taller, and the springiness of the coil springs is mainly exerted, and the damping force of the damper is not easily reduced as it propagates through the first elastic body, the second elastic body, and the third elastic body, and reaches the vehicle body side while remaining high, thereby stabilizing the vehicle. The air chamber is surrounded by the upper base, the lower base, the first elastic body, the second elastic body, and the third elastic body, and no separate member such as an elastic membrane is provided, thereby reducing the bulkiness of the suspension device. Since the suspension device is provided with not only the first and second elastic bodies but also the third elastic body, the spring of the suspension device can be easily adjusted, and since the third elastic body connects the outer tubes of the upper base and the lower base to each other, a large air chamber can be easily secured.

[0008] The air chamber may radially straddle the inner cylinders of the upper base and the lower base.

[0009] Since the air chamber radially straddles the inner cylinders of the upper base and the lower base, the size of the air chamber can be easily ensured.

[0010] A biasing member may be provided between the upper base and the lower base, the biasing member biasing the upper base and the lower base in a direction separating them in the up-down direction.

[0011] Since a biasing member is provided that biases the upper base and the lower base in a direction separating them in the vertical direction, the upper base and the lower base can be easily maintained in a state separated in the vertical direction without excessively increasing the pressure of the pressurized air supplied to the air chamber.

[0012] A guide protrusion protruding radially outward may be provided on the inner tube of either the upper base or the lower base, and when the pressurized air is exhausted from the air chamber by the supply and exhaust mechanism and the upper base and the lower base move relatively closer to each other in the vertical direction, the guide protrusion may abut or come into close proximity to the inner surface of the outer tube of the other of the upper base and the lower base.

[0013] A guide protrusion is provided on the inner tube of either the upper base or the lower base, so that when pressurized air is exhausted from the air chamber, the guide protrusion abuts or comes into close proximity to the inner surface of the outer tube of the other of the upper base or the lower base, thereby preventing the upper base and the lower base from shifting radially relative to each other.

[0014] The upper base has a top wall that integrally closes the upper end openings of the inner tube and the outer tube, and the lower base has a bottom wall that integrally closes the lower end openings of the inner tube and the outer tube, and the first elastic body and the second elastic body may be formed with first elastic protrusions and second elastic protrusions that abut against the top wall and the bottom wall, respectively, when the upper base and the lower base move closer to each other in the vertical direction when pressurized air is exhausted from the air chamber by the supply and exhaust mechanism.

[0015] Since the first elastic body and the second elastic body are respectively formed with the first elastic protrusion and the second elastic protrusion, when the pressurized air is discharged from the air chamber and the upper base and the lower base move relatively closer to each other in the vertical direction, the first elastic body and the second elastic body come into contact with the top wall and the bottom wall via the first elastic protrusion and the second elastic protrusion, respectively, thereby reliably increasing the spring strength of the first elastic body and the second elastic body. As a result, by discharging the pressurized air from the air chamber when the vehicle is traveling at high speed, the vehicle can be reliably stabilized.

[0016] Either the upper base or the lower base may be provided with a third elastic protrusion that abuts against the other of the upper base or the lower base when pressurized air is exhausted from the air chamber by the supply and exhaust mechanism and the upper base and the lower base move closer to each other in the vertical direction.

[0017] Since a third elastic protrusion is provided on either the upper base or the lower base, when pressurized air is exhausted from the air chamber and the upper base and the lower base move closer to each other in the vertical direction, the upper base and the lower base can be butted against each other in the vertical direction via the third elastic protrusion, suppressing the relative movement of the upper base and the lower base.By exhausting the pressurized air from the air chamber when the vehicle is traveling at high speed, the vehicle can be reliably stabilized. Effect of the Invention

[0018] According to this invention, bulkiness can be suppressed. [Brief description of the drawings]

[0019] [Figure 1] 1 is a vertical cross-sectional view of a suspension system according to an embodiment; [Diagram 2] FIG. 2 is a diagram showing a state in which the pressurized air is discharged from the air chamber in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] Hereinafter, one embodiment of a suspension system will be described with reference to FIGS. The suspension device 1 includes an upper base 11 , a lower base 12 , an inner member 13 , a first elastic body 14 , a second elastic body 15 , a third elastic body 16 , and a supply / discharge mechanism 17 . The shape of the suspension device 1 is the same before it is mounted on a vehicle as it is in a state where it is mounted on a vehicle and pressurized air is supplied to an air chamber X, which will be described later.

[0021] The upper base 11 and the lower base 12 are formed in a double cylindrical shape, and the inner member 13, the first elastic body 14, the second elastic body 15, and the third elastic body 16 are formed in a cylindrical shape. The upper base 11, the lower base 12, the inner member 13, the first elastic body 14, the second elastic body 15, and the third elastic body 16 are arranged coaxially with a common axis. Hereinafter, this common axis will be referred to as the central axis O, the direction along the central axis O will be referred to as the vertical direction, the direction that intersects the central axis O when viewed from the vertical direction will be referred to as the radial direction, and the direction that rotates around the central axis O will be referred to as the circumferential direction.

[0022] The suspension device 1 is connected to the upper end of a rod 52 of a damper 51, and supports the upper end of a coil spring 53. The damper 51 and the coil spring 53 extend in the vertical direction. The lower end of a cylinder 54 of the damper 51 is connected to a support device for the axle. The damper 51 is inserted inside the coil spring 53. The damper 51 and the coil spring 53 are arranged coaxially. The rod 52 protrudes upward from the cylinder 54. The portion of the rod 52 protruding upward from the cylinder 54 is surrounded from the radial outside by a bump stopper 55. A male thread portion is formed on the upper end portion of the rod 52 protruding upward from the bump stopper 55.

[0023] The upper base 11 comprises an inner tube (hereinafter referred to as the upper inner tube) 21, an outer tube (hereinafter referred to as the upper outer tube) 22 that surrounds the upper inner tube 21 from the radial outside, and a top wall 23 that integrally closes the upper end openings of the upper inner tube 21 and the upper outer tube 22, and is connected to the vehicle body B. A through hole is formed in the top wall 23 in a portion located radially inward from the upper inner cylinder 21. The through hole is disposed coaxially with the central axis O, and the inner diameter of the through hole is larger than the outer diameter of the inner member 13. The lower end of the upper outer cylinder 22 is located lower than the lower end of the upper inner cylinder 21.

[0024] The lower base 12 is provided below the upper base 11 so as to be movable upward relatively to the upper base 11 , and supports the upper end of the coil spring 53 . The lower base 12 comprises an inner tube (hereinafter referred to as the lower inner tube) 25, an outer tube (hereinafter referred to as the lower outer tube) 26 that surrounds the lower inner tube 25 from the radial outside, and a bottom wall 27 that integrally closes the lower end openings of the lower inner tube 25 and the lower outer tube 26.

[0025] The upper end of the lower outer cylinder 26 is located above the upper end of the lower inner cylinder 25. The lower end of the lower outer cylinder 26 is located below the upper end of the lower inner cylinder 25 and above the lower end of the lower inner cylinder 25. The outer periphery of the bottom wall 27 protrudes radially outward from the lower outer cylinder 26. The portion of the bottom wall 27 located radially outward from the lower inner cylinder 25 is located above the portion located radially inward from the lower inner cylinder 25. A through hole is formed in the portion of the bottom wall 27 located radially inward from the lower inner cylinder 25. The through hole is arranged coaxially with the central axis O, and the inner diameter of the through hole is larger than the outer diameter of the inner member 13.

[0026] The lower base 12 is formed with a mounting tube 12a that protrudes downward from the bottom wall 27. The upper end of the bump stopper 55 is fitted into the mounting tube 12a. The diameter of the mounting tube 12a is equal to the diameter of the lower inner tube 25. The connection portion between the outer circumferential surface of the mounting tube 12a and the lower surface of the bottom wall 27 supports the upper end of the coil spring 53.

[0027] The upper end opening edge of the lower inner cylinder 25 is located below and vertically opposed to the lower end opening edge of the upper inner cylinder 21. The radial positions of the lower inner cylinder 25 and the upper inner cylinder 21 may be different from each other. The lower outer cylinder 26 is located radially inward from the upper outer cylinder 22. The lower outer cylinder 26 may be located radially outward from the upper outer cylinder 22. The upper end of the lower outer cylinder 26 is located higher than the lower end of the upper outer cylinder 22. The upper end of the lower outer cylinder 26 and the lower end of the upper inner cylinder 21 are positioned at the same vertical position. The relative vertical positions of the upper end of the lower outer cylinder 26 and the lower ends of the upper inner cylinder 21 and upper outer cylinder 22 may be changed as appropriate.

[0028] The inner member 13 is provided radially inward from the upper inner cylinder 21 and the lower inner cylinder 25. The upper end of the inner member 13 is located above the lower end of the upper inner cylinder 21. The lower end of the inner member 13 is located below the upper end of the lower inner cylinder 25. The inner member 13 is formed in a cylindrical shape with both vertical ends open. A partition wall 13a that divides the inside of the inner member 13 in the vertical direction is formed in the vertical center of the inner circumferential surface of the inner member 13.

[0029] The upper end of the rod 52 of the damper 51 is inserted into the inner member 13 through a through hole in the bottom wall 27. The upper end of the rod 52 passes through the partition wall 13a in the vertical direction. A nut N is screwed onto the upper end of the rod 52, at a portion that protrudes upward from the partition wall 13a. An upwardly facing step is formed on a portion of the upper end of the rod 52 that is located below the partition wall 13a. The upper end of the rod 52, at a portion that protrudes downward from the underside of the partition wall 13a, is inserted inside a fixing ring 57 that is disposed on the step. A nut N is fastened to the upper end of the rod 52, and the upper end of the rod 52 is fixed to the inner member 13 by sandwiching the partition wall 13a and the fixing ring 57 between the nut N and the step portion in the vertical direction.

[0030] The first elastic body 14 and the second elastic body 15 connect the upper inner tube 21 and the lower inner tube 25 to the inner member 13, respectively. The first elastic body 14 and the second elastic body 15 are formed of, for example, a rubber material or the like so as to be elastically deformable. The first elastic body 14 extends upward from the inside to the outside in the radial direction, and the second elastic body 15 extends downward from the inside to the outside in the radial direction.

[0031] The inner peripheral surface of the first elastic body 14 is bonded to the outer peripheral surface of the first metal tube 14a fitted onto the inner member 13, and the outer peripheral surface of the first elastic body 14 is bonded to the inner peripheral surface of the second metal tube 14b fitted into the upper inner tube 21. The inner peripheral surface of the second elastic body 15 is bonded to the outer peripheral surface of the third metal tube 15a fitted onto the inner member 13, and the outer peripheral surface of the second elastic body 15 is bonded to the inner peripheral surface of the fourth metal tube 15b fitted into the lower inner tube 25. The first metal tube 14a is located above the third metal tube 15a, and the first metal tube 14a and the third metal tube 15a butt against each other in the vertical direction.

[0032] The third elastic body 16 connects the upper outer cylinder 22 and the lower outer cylinder 26 to each other. The third elastic body 16 is made of, for example, a rubber material and is elastically deformable. The third elastic body 16 extends upward from the inside to the outside in the radial direction. The volume of the third elastic body 16 is larger than the volumes of the first elastic body 14 and the second elastic body 15. The inner surface of the third elastic body 16 is adhered to the outer surface of a fifth metal tube 16a fitted onto the lower outer tube 26, and the outer surface of the third elastic body 16 is adhered to the inner surface of a sixth metal tube 16b fitted into the upper outer tube 22.

[0033] Between the top wall 23 of the upper base 11 and the bottom wall 27 of the lower base 12, an air chamber X is provided that is airtightly surrounded by the upper base 11, the lower base 12, the first elastic body 14, the second elastic body 15, and the third elastic body 16. The air chamber X straddles the upper inner tube 21 and the lower inner tube 25 in the radial direction. The air chamber X is formed in an annular shape and is disposed coaxially with the central axis O. The internal volume of the air chamber X at a portion located radially inward relative to the upper inner tube 21 and the lower inner tube 25 is smaller than the internal volume of the portion located radially outward. The portion of the air chamber X located radially inward relative to the upper inner tube 21 and the lower inner tube 25 is provided in the center in the up-down direction between the top wall 23 of the upper base 11 and the bottom wall 27 of the lower base 12.

[0034] The supply and exhaust mechanism 17 supplies and exhausts pressurized air to and from the air chamber X. As the supply and exhaust mechanism 17 supplies and exhausts pressurized air, the first elastic body 14, the second elastic body 15, and the third elastic body 16 elastically deform and expand and contract in the air chamber X, causing the upper base 11 and the lower base 12 to move relative to each other in the vertical direction. This allows the vehicle height to be adjusted. The supply and exhaust mechanism 17 includes an air intake pipe P1, an exhaust pipe P2, an air intake valve V1, an exhaust valve V2, a check valve V3, and a pump (not shown).

[0035] The air intake pipe P1 and the exhaust pipe P2 communicate with the air chamber X, and pressurized air is supplied from the pump to the air chamber X through the air intake pipe P1, and the pressurized air in the air chamber X is exhausted through the exhaust pipe P2. The air intake pipe P1 and the exhaust pipe P2 open into a portion of the air chamber X that is located radially outward from the upper inner cylinder 21 and the lower inner cylinder 25. The air intake valve V1 is provided in the air intake pipe P1 and switches between connecting and blocking communication between the air chamber X and the pump. The exhaust valve V2 is provided in the exhaust pipe P2 and switches between retaining the pressurized air in the air chamber X and exhausting it. The check valve V3 is provided in the air supply pipe P1 at a portion located between the air supply valve V1 and the pump, and allows a flow from the pump to the air chamber X and restricts a flow in the reverse direction. An air tank may be provided in the air supply pipe P1 at a portion located between the check valve V3 and the pump.

[0036] Here, the suspension system 1 includes a speed sensor (not shown) that detects the traveling speed of the vehicle, and a control unit (not shown) that switches the opening and closing of the intake valve V1 and the exhaust valve V2 based on an output signal from the speed sensor.

[0037] When the control unit determines, based on the output signal from the speed sensor, that the vehicle is traveling at a normal speed, it opens the intake valve V1 with the exhaust valve V2 closed, and supplies pressurized air from the pump through the intake pipe P1 to the air chamber X, maintaining the upper base 11 and the lower base 12 spaced apart in the vertical direction, just as they were before the suspension device 1 was attached to the vehicle, as shown in FIG. 1. When the control unit determines, based on the output signal from the speed sensor, that the vehicle is traveling at high speed, it opens the exhaust valve V2 while keeping the intake valve V1 closed, exhausts the pressurized air from the air chamber X, and brings the upper base 11 and the lower base 12 closer together in the vertical direction, as shown in FIG. 2.

[0038] Here, in this embodiment, a guide protrusion 31 protruding radially outward is provided on the inner tube of either the upper base 11 or the lower base 12, and as shown in Figure 2, when pressurized air is exhausted from the air chamber X by the supply and exhaust mechanism 17 and the upper base 11 and the lower base 12 move relatively closer to each other in the vertical direction, the guide protrusion 31 abuts against or comes close to the inner surface of the outer tube of the other of the upper base 11 and the lower base 12.

[0039] In the illustrated example, the guide protrusion 31 is provided on the outer circumferential surface of the upper inner tube 21. When the pressurized air is exhausted from the air chamber X by the supply and exhaust mechanism 17 and the upper base 11 and the lower base 12 are moved relatively closer to each other in the vertical direction, the guide protrusion 31 comes into contact with or comes close to the inner circumferential surface of the lower outer tube 26.

[0040] Furthermore, by positioning the lower outer tube 26 radially outward from the upper outer tube 22 and providing a guide protrusion 31 on the outer peripheral surface of the lower inner tube 25, when the pressurized air is exhausted from the air chamber X by the supply and exhaust mechanism 17 and the upper base 11 and the lower base 12 are moved relatively closer to each other in the vertical direction, the guide protrusion 31 may be brought into contact with or close to the inner peripheral surface of the upper outer tube 22.

[0041] The guide protrusion 31 is formed integrally with the top wall 23 of the upper base 11. The guide protrusion 31 extends continuously over the entire circumferential length. The guide protrusion 31 has a rectangular shape in a vertical cross section, with a pair of sides extending in the vertical direction and the remaining pair of sides extending in the radial direction. The lower end surface of the guide protrusion 31 is located above the lower end opening edge of the upper inner tube 21. The guide protrusion 31 has a chamfered portion 31a at the connection between the lower end surface and the outer circumferential surface.

[0042] Between the upper base 11 and the lower base 12, a biasing member 32 is provided which biases the upper base 11 and the lower base 12 in a direction to separate them in the vertical direction. The biasing member 32 is a coil spring, and is disposed coaxially with the central axis O. The biasing member 32 is inserted between the outer peripheral surface of the lower inner cylinder 25 and the inner peripheral surface of the lower outer cylinder 26. An upper end of the biasing member 32 is supported by a lower end surface of the guide protrusion 31.

[0043] The first elastic body 14 and the second elastic body 15 are formed with a first elastic protrusion 33 and a second elastic protrusion 34 which respectively abut against the top wall 23 of the upper base 11 and the bottom wall 27 of the lower base 12 when pressurized air is exhausted from the air chamber X by the supply and exhaust mechanism 17 and the upper base 11 and the lower base 12 move relatively closer to each other in the vertical direction.

[0044] The first elastic protrusion 33 and the second elastic protrusion 34 extend continuously over the entire circumferential length. The first elastic protrusion 33 protrudes upward from the upper end surface of the first elastic body 14, and the second elastic protrusion 34 protrudes downward from the lower end surface of the second elastic body 15. The first elastic protrusion 33 is provided at the radial center of the upper end surface of the first elastic body 14, and the second elastic protrusion 34 is provided at the radial center of the lower end surface of the second elastic body 15.

[0045] Either the upper base 11 or the lower base 12 is provided with a third elastic protrusion 35 which abuts against the other of the upper base 11 or the lower base 12 when the pressurized air is exhausted from the air chamber X by the supply and exhaust mechanism 17 and the upper base 11 and the lower base 12 move closer to each other in the vertical direction.

[0046] In the illustrated example, the third elastic protrusion 35 is provided on the lower base 12. The third elastic protrusion 35 is provided on the edge of the upper end opening of the lower outer cylinder 26. The third elastic protrusion 35 extends continuously over the entire circumferential length. The third elastic protrusion 35 is formed integrally with the third elastic body 16. The third elastic protrusion 35 may be provided on, for example, the lower inner cylinder 25, the bottom wall 27, the upper base 11, or the like.

[0047] The spring constants of the first elastic body 14, the second elastic body 15, the third elastic body 16, and the biasing member 32 are set so that when the suspension device 1 is mounted on a vehicle and the pressurized air is exhausted from the air chamber X by the supply and exhaust mechanism 17, the upper base 11 and the lower base 12 abut or are close to each other in the vertical direction. At this time, the first elastic body 14 and the top wall 23, the second elastic body 15 and the bottom wall 27, and the third elastic body 16 and the top wall 23 come into contact with or close to each other in the vertical direction.

[0048] Furthermore, in the illustrated example, as shown in Figure 2, the upper end opening edge of the lower outer tube 26 comes close to the underside of the top wall 23 of the upper base 11, the first elastic protrusion 33 and the third elastic protrusion 35 abut against the underside of the top wall 23 and are compressed and deformed in the vertical direction, and the second elastic protrusion 34 abuts against the upper surface of the bottom wall 27 and is compressed and deformed in the vertical direction, so that the lower end opening edge of the upper inner tube 21 and the upper end opening edge of the lower inner tube 25 come close to each other in the vertical direction.

[0049] 1, when vibration is input with pressurized air being supplied to the air chamber X by the supply / discharge mechanism 17, not only the coil spring 53 but also the first elastic body 14, the second elastic body 15, and the third elastic body 16 elastically deform, causing the upper base 11 and the lower base 12 to relatively displace, and the damping force of the damper 51 is reduced by being propagated through the first elastic body 14, the second elastic body 15, and the third elastic body 16 via the inner member 13, and reaches the vehicle body B. As a result, by supplying pressurized air to the air chamber X during normal vehicle driving, a comfortable ride can be ensured.

[0050] 2, when the pressurized air is exhausted from the air chamber X by the supply and exhaust mechanism 17, the first elastic body 14, the second elastic body 15, and the third elastic body 16 are compressed and deformed, and the upper base 11 and the lower base 12 move relatively closer to each other in the vertical direction, so that the springs of the first elastic body 14, the second elastic body 15, and the third elastic body 16 become taller. As a result, when the vehicle is traveling at high speed, by exhausting the pressurized air from the air chamber X, the springs of the first elastic body 14, the second elastic body 15, and the third elastic body 16 become taller, and the spring of the coil spring 53 is mainly exerted, and the damping force of the damper 51 is not easily reduced when propagating through the first elastic body 14, the second elastic body 15, and the third elastic body 16, and reaches the vehicle body B side while remaining high, thereby stabilizing the vehicle.

[0051] The air chamber X is surrounded by the upper base 11, the lower base 12, the first elastic body 14, the second elastic body 15, and the third elastic body 16, and no separate member such as an elastic membrane is provided, so that the bulkiness of the suspension device 1 can be suppressed. Since the suspension device 1 is provided with not only the first elastic body 14 and the second elastic body 15 but also the third elastic body 16, the spring of the suspension device 1 can be easily adjusted, and since the third elastic body 16 connects the upper outer tube 22 and the lower outer tube 26 to each other, a wide air chamber X can be easily secured.

[0052] Since the air chamber X spans the upper inner cylinder 21 and the lower inner cylinder 25 in the radial direction, the size of the air chamber X can be easily ensured.

[0053] Since a biasing member 32 is provided for biasing the upper base 11 and the lower base 12 in a direction to separate them in the vertical direction, the upper base 11 and the lower base 12 can be easily maintained in a state separated in the vertical direction without excessively increasing the pressure of the pressurized air supplied to the air chamber X.

[0054] Since a guide protrusion 31 is provided on the upper inner tube 21, when pressurized air is exhausted from the air chamber X, the guide protrusion 31 abuts or comes into close proximity to the inner surface of the lower outer tube 26, thereby preventing the upper base 11 and the lower base 12 from shifting in their radial position relative to each other.

[0055] Since the first elastic body 14 and the second elastic body 15 are respectively formed with the first elastic protrusion 33 and the second elastic protrusion 34, when the pressurized air is exhausted from the air chamber X and the upper base 11 and the lower base 12 move relatively closer to each other in the vertical direction, the first elastic body 14 and the second elastic body 15 come into contact with the top wall 23 and the bottom wall 27 via the first elastic protrusion 33 and the second elastic protrusion 34, respectively, thereby reliably increasing the spring strength of the first elastic body 14 and the second elastic body 15. As a result, by exhausting the pressurized air from the air chamber X when the vehicle is traveling at high speed, the vehicle can be reliably stabilized.

[0056] Since the lower base 12 is provided with the third elastic protrusion 35, when pressurized air is exhausted from the air chamber X and the upper base 11 and the lower base 12 move relatively closer to each other in the vertical direction, the upper base 11 and the lower base 12 can be abutted against each other in the vertical direction via the third elastic protrusion 35, thereby suppressing the relative movement of the upper base 11 and the lower base 12. By exhausting the pressurized air from the air chamber X when the vehicle is traveling at high speed, the vehicle can be reliably stabilized.

[0057] The technical scope of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

[0058] For example, the air chamber X may be provided only on the outer side or the inner side in the radial direction with respect to the upper inner cylinder 21 and the lower inner cylinder 25. The guide protrusion 31, the first elastic protrusion 33, the second elastic protrusion 34, and the third elastic protrusion 35 do not necessarily have to be provided.

[0059] In addition, within the scope of the spirit of the present invention, it is possible to replace the components in the above-described embodiments with well-known components as appropriate, and the above-described embodiments and variations may be combined as appropriate. [Explanation of symbols]

[0060] 1 Suspension system 11 Upper Base 12 Lower Base 13 Inner member 14 First Elastic Body 15 Second Elastic Body 16 Third Elastic Body 17 Supply / discharge mechanism 21 Upper inner tube (inner tube) 22 Upper outer tube (outer tube) 23 Top Wall 25 Lower inner cylinder (inner cylinder) 26 Lower outer tube (outer tube) 27 Bottom Wall 31 Guide protrusion 32 Pressurizing member 33 First elastic protrusion 34 Second elastic protrusion 35 Third elastic protrusion 51 Damper 52 Rod 53 Coil spring B. Body X Air Chamber

Claims

1. A double-tube upper base connected to the vehicle body; a lower base having a double cylindrical shape, the lower base being disposed below the upper base and movable upward relative to the upper base, and supporting an upper end of a coil spring; an inner member provided radially inward from an inner cylinder of each of the upper base and the lower base and connected to an upper end of a rod of a damper; a first elastic body and a second elastic body respectively connecting the inner cylinders of the upper base and the inner member of the lower base; a third elastic body connecting the outer cylinders of the upper base and the lower base to each other; a supply and exhaust mechanism that supplies and exhausts pressurized air to and from an air chamber surrounded by the upper base, the lower base, the first elastic body, the second elastic body, and the third elastic body, the air chamber expands and contracts while being elastically deformed by the first elastic body, the second elastic body, and the third elastic body in association with the supply and exhaust of the pressurized air, and the upper base and the lower base move relatively in the up-down direction; A suspension device in which, when the pressurized air is exhausted from the air chamber by the supply and exhaust mechanism, the first elastic body, the second elastic body, and the third elastic body are compressed and deformed, while the upper base and the lower base move closer to each other in the vertical direction.

2. The suspension device according to claim 1 , wherein the air chamber radially straddles inner cylinders of the upper base and the lower base.

3. 3. The suspension device according to claim 1, further comprising a biasing member disposed between said upper base and said lower base for biasing said upper base and said lower base in a direction to separate them in the up-down direction.

4. a guide protrusion protruding radially outward is provided on an inner cylinder of either the upper base or the lower base, 4. A suspension device according to claim 1, wherein when pressurized air is exhausted from the air chamber by the supply and exhaust mechanism and the upper base and the lower base move relatively closer to each other in the vertical direction, the guide protrusion abuts against or approaches an inner circumferential surface of an outer tube of the other of the upper base and the lower base.

5. the upper base has a top wall that integrally closes the upper end openings of the inner cylinder and the outer cylinder, the lower base has a bottom wall that integrally closes the lower end openings of the inner cylinder and the outer cylinder, 5. A suspension device as claimed in any one of claims 1 to 4, wherein the first elastic body and the second elastic body are formed with a first elastic protrusion and a second elastic protrusion that respectively abut against the top wall and the bottom wall when the pressurized air is exhausted from the air chamber by the supply and exhaust mechanism and the upper base and the lower base move relatively closer to each other in the vertical direction.

6. 6. A suspension device as claimed in any one of claims 1 to 5, wherein one of the upper base and the lower base is provided with a third elastic protrusion that abuts against the other of the upper base and the lower base when the supply and exhaust mechanism exhausts pressurized air from the air chamber and the upper base and the lower base move closer to each other in the vertical direction.

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