JP6438338B2 - Front fork - Google Patents

Description

  Embodiments of the present invention relate to a front fork.

  In a motorcycle, a front wheel is attached to a front fork connected to a front portion of a vehicle body, and a rear wheel is attached to a rear suspension connected to a rear portion of the vehicle body. When the motorcycle travels, the impact caused by the vertical movement of the front and rear wheels that are in contact with the ground is transmitted to the vehicle body through the front fork and the rear suspension. In order to improve the riding comfort during traveling of a motorcycle, it is required to reduce the impact transmitted from the ground to the vehicle body.

  Some spring legs of conventional front forks do not incorporate a suspension spring made of a metal spring but incorporate a suspension spring made of an air spring. In the spring leg, the vehicle body side tube and the axle side tube are inserted into each other, and a piston rod guide member provided at the center of the axle side tube is inserted into the vehicle body side tube. The vehicle body side tube has a positive air spring chamber formed by the guide member of the piston rod. Further, the vehicle body side tube is a negative air spring chamber (formed between a rod guide provided on the vehicle body side tube for inserting and supporting the piston rod and a guide member for the piston rod inserted into the vehicle body side tube ( Hereinafter, it is also referred to as “rebound air spring chamber”.

  And this spring leg is urged | biased in the direction which expands a vehicle body side tube and an axle side tube with the positive spring force which arises in the positive air spring chamber compressed by the compression side stroke. The spring leg urges the vehicle body side tube and the axle side tube in a contracting direction by a negative spring force (rebound reaction force) generated in the negative air spring chamber compressed in the extension side stroke.

JP-T-2001-501155

  In a spring leg that constitutes a front fork with a built-in suspension spring composed of a conventional air spring, the spring leg is compressed against the load applied to the spring leg during the compression stroke according to the amount of oil charged in the spring leg. The amount, ie the compression rate of the spring leg, is adjusted. When reducing the compression rate of the spring legs, it is necessary to increase the amount of oil filled in the spring legs. In order to increase the amount of oil filled in the spring leg, it is necessary to disassemble the spring leg each time, or to open the oil input portion provided in the spring leg and to supply oil to the spring leg each time. Furthermore, when the desired compression ratio of the spring leg cannot be achieved after the oil is supplied, the oil must be supplied again by disassembling the spring leg or opening the oil input part again. For this reason, the number of work steps consumed for reducing the compression rate of the spring legs is large, and the work time is long. Furthermore, since oil is required to reduce the compression ratio of the spring leg, there is a problem that the working environment is limited.

  An object of this invention is to provide the front fork which can reduce a compression rate easily, in a short time, and without being restrict | limited to a working environment.

The front fork of the embodiment is a front fork including a pair of first legs and second legs, wherein at least one of the first leg and the second leg is provided on a vehicle body side, and an upper end side is closed. A vehicle body side tube that is open on the lower end side, provided on the axle side, is opened on the upper end side, is closed on the lower end side, is connected to the vehicle body side tube, and extends along the axial direction of the vehicle body side tube with respect to the vehicle body side tube A relatively moving axle side tube, a guide cylinder extending along the axial direction, having an upper end attached to the upper end side of the vehicle body side tube and closed, and a lower end opened, and the axial direction A cylindrical piston lock that extends along the axial direction, is attached to the lower end side of the axle-side tube, has an open upper end, and moves relative to the guide cylinder along the axial direction. Provided with a door. Further, at least one of the first leg and the second leg of the front fork is provided at an opening of the guide cylinder, and a rod guide that slidably supports the piston rod, and an opening of the piston rod. A first piston, which is provided while maintaining an opening, is slidably inserted into the guide cylinder, and an upper end portion is attached to the upper end portion side of the guide cylinder, and extends in the axial direction within the guide cylinder. An adjusting rod that is extendable and set to a predetermined length, and is provided at a lower end portion of the adjusting rod, and a space in the guide cylinder above the first piston is defined as a first chamber and the And a second piston that divides into a second chamber below the first chamber. In addition, at least one of the first leg and the second leg further includes a first detection unit that detects the pressure in the first chamber, and a second detection that detects the pressure in the second chamber. A part.

1 is a side view schematically showing a schematic configuration of a motorcycle including a first front fork of an embodiment. It is a longitudinal section showing a schematic structure of the 1st front fork of an embodiment typically. It is a longitudinal cross-sectional view which expands and schematically shows schematic structure of the upper end part of the 1st front fork of embodiment. It is a top view which shows typically schematic structure of the 1st front fork of embodiment.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a side view schematically showing a schematic configuration of a motorcycle 2 provided with a first front fork 10 of an embodiment. The motorcycle 2 includes a body frame 3 constituting a part of a vehicle body, a head pipe 4 attached to a front end portion of the body frame 3, a front fork 1 provided on the head pipe 4, and a lower end of the front fork 1. And a front wheel 6 </ b> A attached to the part via an axle 5. The front fork 1 has a first front fork 10 as a first leg and a second front fork (not shown) as a second leg. In FIG. 1, only the first front fork 10 disposed on the right side of the front wheel 6A in the traveling direction is shown, and the second front fork disposed on the left side of the front wheel 6A in the traveling direction is illustrated. Absent. Here, an example is shown in which the first front fork 10 is provided on the right side in the traveling direction, but the first front fork 10 may be provided on the left side in the traveling direction.

  The motorcycle 2 includes a handle 7 attached to the upper part of the front fork 1, a swing arm 8 attached to the lower part of the vehicle body frame 3 so as to freely swing, and a rear wheel attached to the rear end of the swing arm 8. 6B, and a rear suspension 9 attached between the swing arm 8 and the vehicle body frame 3. The rear suspension 9 has a first rear suspension 9A and a second rear suspension (not shown). In FIG. 1, only the first rear suspension 9A disposed on the right side of the rear wheel 6B in the traveling direction is shown, and the second rear suspension disposed on the left side of the rear wheel 6B in the traveling direction is illustrated. Not shown. Here, an example is shown in which the first rear suspension 9A is provided on the right side in the traveling direction, but the first rear suspension 9A may be provided on the left side in the traveling direction.

  A handle rotation shaft (not shown) provided integrally with the handle 7 and the front fork 1 is inserted into the head pipe 4, and the head pipe 4 rotatably supports the handle rotation shaft. The front wheel 6 </ b> A is a wheel arranged on the front side in the traveling direction of the body frame 3. The handle 7 is a member that is disposed on the front side in the traveling direction of the vehicle body frame 3 and that is gripped by the driver for steering the motorcycle 2. The front fork 1 is a shock absorber that suppresses transmission of an impact received by the front wheels 6A to the vehicle body frame 3 during traveling due to unevenness of the ground.

  The swing arm 8 is a member that is rotatably supported by the vehicle body frame 3 at the front end in the traveling direction, and that supports the rear wheel 6B at the rear end in the traveling direction. The swing arm 8 rotates around the front end in the traveling direction so as to follow the movement of the rear wheel 6B. The rear wheel 6 </ b> B is a wheel disposed on the rear side in the traveling direction of the body frame 3. The rear suspension 9 is a shock absorber that suppresses transmission of an impact received by the rear wheel 6B to the vehicle body frame 3 during traveling due to unevenness of the ground.

  Next, the configuration of the first front fork 10 will be described. FIG. 2 is a longitudinal sectional view schematically showing a schematic configuration of the first front fork 10 of the embodiment. FIG. 3 is a longitudinal sectional view schematically showing an enlarged schematic configuration of the upper end portion of the first front fork of the embodiment. FIG. 4 is a top view schematically showing a schematic configuration of the first front fork 10 of the embodiment. The first front fork 10 is a so-called spring leg that does not incorporate a damping mechanism such as a damper. The first front fork 10 does not include a suspension spring made of a metal spring, but has a suspension spring 40 made of an air spring. The second front fork is a so-called damper leg that incorporates a damping mechanism such as a damper. However, the second front fork may have the same configuration as the first front fork 10.

  The first front fork 10 includes a vehicle body side tube 11 and an axle side tube 12 arranged coaxially. The vehicle body side tube 11 is supported by a head pipe 4 disposed on the vehicle body side via a stem bracket. The axle side tube 12 is coupled to the axle 5 and moves relative to the vehicle body side tube 11 along the axial direction of the vehicle body side tube 11. The vehicle body side tube 11 and the axle side tube 12 are substantially cylindrical members. The upper end side of the vehicle body side tube 11 is closed, and the lower end side is open. The upper end side of the axle side tube 12 is opened, and the lower end side is closed. Hereinafter, the direction of the center line of the vehicle body side tube 11 and the axle side tube 12 may be referred to as “vertical direction”, the vehicle body frame 3 side may be referred to as “upper side”, and the front wheel 6A side may be referred to as “lower side”.

  The upper end portion of the vehicle body side tube 11 is closed and sealed with a cap 30 and a fork bolt 31. The upper end of the guide cylinder 21 is connected to the lower end of the cap 30. As an example, FIGS. 2 to 3 show a configuration in which the guide cylinder 21 and the cap 30 formed by fitting the upper end outer peripheral surface of the lower cylinder 21L to the lower end inner peripheral surface of the upper cylinder 21U are integrated. The guide cylinder 21 is closed at the upper end and extends downward along the axial direction of the vehicle body side tube 11. A rod guide 36 is screwed into an opening formed at the lower end of the guide cylinder 21. An anti-sway collar 25 is attached to the outer peripheral portion on the lower end side of the guide cylinder 21 via an inner peripheral surface of the axle-side tube 12 and an annular gap.

  The axle side tube 12 is hermetically sealed via a bush 13A, a bush 13B, and a seal member 13C, and is slidably inserted into the inner peripheral surface of the vehicle body side tube 11. The lower end portion of the axle tube 12 is screwed and sealed by a fitting portion 32A of the axle bracket 32. The lower end surface of the axle tube 12 is pinched by the inner peripheral surface of the fitting portion 32A and the outer peripheral surface of the bottom piece 33 provided on the bottom surface.

  The lower end portion of the piston rod 22 is connected to the center portion of the axle bracket 32 inside the axle side tube 12. The cylindrical piston rod 22 extends upward along the axial direction of the axle tube 12. The upper end of the piston rod 22 is open. The lower end portion of the piston rod 22 is screwed to a bottom bolt 34 that is provided at the bottom portion of the axle bracket 32 and seals the axle-side tube 12 and is fixed by a lock nut 35 from above. The axle bracket 32 is formed with an axle support hole 32B to which the axle 5 of the front wheel 6A can be attached.

  The piston rod 22 is slidably supported by a bush 37 provided in a rod guide 36 provided at an opening of the guide cylinder 21, and is relatively laid along the axial direction of the vehicle body side tube 11 with respect to the guide cylinder 21. Moving. The piston 23 is screwed into the opening of the piston rod 22 inserted into the guide cylinder 21 while maintaining the opening of the piston rod 22. The piston 23 is slidably inserted into the inner peripheral surface of the guide cylinder 21 between a rod guide 36 provided at the opening of the guide cylinder 21 and the upper end portion of the guide cylinder 21. A piston ring 24 slidably contacting the inner peripheral surface of the guide cylinder 21 is attached to the outer periphery of the piston 23. The rod guide 36 includes a seal retainer 72A and a rubber stopper 72B held by the seal retainer 72A.

  Inside the guide cylinder 21, the first front fork 10 is an inner air formed between a piston 23 provided at the upper end of the piston rod 22 and a fork bolt 31 provided at the upper end of the guide cylinder 21. A spring chamber 50 is provided. Further, the first front fork 10 includes an outer air spring chamber 60 which is an annular space formed between the vehicle body side tube 11 and the axle side tube 12, the guide cylinder 21 and the piston rod 22. The first front fork 10 is inserted into the guide cylinder 21 and a rod guide 36 that is provided in the opening of the guide cylinder 21 inside the guide cylinder 21 and supports the piston rod 22 in a slidable manner. A rebound air spring chamber 70 formed between the piston rod 22 and the piston 23 provided at the opening of the piston rod 22. The rebound air spring chamber 70 is located below the inner air spring chamber 50. The air spring of the inner air spring chamber 50, the air spring of the outer air spring chamber 60, and the air spring of the rebound air spring chamber 70 constitute the suspension spring 40 of the first front fork 10.

  The inner air spring chamber 50 is a space sandwiched between the fork bolt 31 and the piston 23 inside the guide cylinder 21 where the piston rod 22 does not exist. The inner air spring chamber 50 includes seal members 51 and 71 of the piston 23 provided with respect to the inner peripheral surface of the guide cylinder 21, and a seal member 52 of the fork bolt 31 provided with respect to the inner peripheral surface of the cap 30. The upper end portion to be described later is hermetically sealed by the seal member 53 of the fork bolt 31 provided on the outer peripheral surface of the adjustment rod 56 attached to the upper end portion side of the guide cylinder 21. Furthermore, the inner air spring chamber 50 is hermetically sealed by a seal member 21S interposed in a fitting portion between the upper cylinder 21U and the lower cylinder 21L.

  As shown in FIG. 3, a cover 54 is screwed to the fork bolt 31. At the center of the cover 54, an opening 54B having a screw portion 54A is formed. A rotating member 55 having a threaded portion 55A on the outer peripheral surface is screwed into the opening 54B. The lower end of the rotating member 55 connects the inside of the guide cylinder 21 to an adjusting rod 56 that extends downward along the axial direction of the vehicle body side tube 11. The rotating member 55 extends along the axial direction of the vehicle body side tube 11, and the upper end portion of the rotating member 55 is positioned above the upper surface of the cover 54. When the rotating member 55 rotates, the rotating member 55 moves in the axial direction of the vehicle body side tube 11 with respect to the cover 54 while the threaded portion 55A of the rotating member 55 engages with the threaded portion 54A formed on the inner peripheral surface of the cover 54. Along the vertical direction along.

  The adjustment rod 56 is provided in the guide cylinder 21 so as to be able to expand and contract along the axial direction of the vehicle body side tube 11 and is set to a predetermined length in the guide cylinder 21. The adjusting rod 56 includes a first adjusting rod portion 56A located at the upper portion and a second adjusting rod portion 56B located at the lower portion, which are arranged coaxially. The diameter of the first adjusting rod portion 56A is larger than the diameter of the second adjusting rod portion 56B. Further, the lower end portion of the rotating member 55 is fitted on the upper surface of the first adjusting rod portion 56A.

  A piston 57 is provided in the second adjustment rod portion 56B inserted into the inner air spring chamber 50. An inner seal member 58 is loaded in the inner peripheral recess 57 </ b> A of the piston 57. The inner seal member 58 seals between the inner peripheral surface of the piston 57 and the outer peripheral surface of the second adjustment rod portion 56B. An outer seal member 59 is loaded in the outer peripheral annular groove 57 </ b> B of the piston 57. The piston 57 slides freely on the inner peripheral surface of the guide cylinder 21 in the vertical direction along the axial direction of the vehicle body side tube 11 via the outer seal member 59.

  A ring member 62 is provided on the outer peripheral portion of the lower end of the second adjustment rod portion 56B. The outer diameter of the ring member 62 is larger than the inner diameter of the piston 57. Further, the outer diameter of the first adjusting rod portion 56 </ b> A is larger than the inner diameter of the piston 57.

  The piston 57 arranges the inner air spring chamber 50 along the axial direction of the vehicle body side tube 11 on the first inner air spring chamber 50 </ b> A disposed on the upper side of the guide cylinder 21 and on the lower side of the guide cylinder 21. And the second inner air spring chamber 50B. A first adjustment rod portion 56A is disposed in the first inner air spring chamber 50A, and a bottom surface of the second adjustment rod portion 56B is disposed in the second inner air spring chamber 50B.

  As the rotating member 55 rotates, the adjusting rod 56 connected to the rotating member 55 expands and contracts in the guide cylinder 21 in the vertical direction along the axial direction of the vehicle body side tube 11. As the adjusting rod 56 expands and contracts, the piston 57 moves in the vertical direction along the axial direction of the vehicle body side tube 11 in the inner air spring chamber 50 defined above the piston 23. The piston 57 is a piston that arbitrarily moves in the vertical direction in accordance with the rotation of the rotating member 55. If the rotating member 55 does not rotate, the piston 57 does not move.

  When the rotating member 55 rotates clockwise, the adjustment rod 56 advances downward with respect to the inner air spring chamber 50. The piston 57 moves from the first inner air spring chamber 50A against the pressure of the second inner air spring chamber 50B while the lower end surface of the first adjusting rod portion 56A abuts the upper surface near the inner periphery of the piston 57. It moves in the direction of the second inner air spring chamber 50B. As the piston 57 moves in the direction of the second inner air spring chamber 50B, the second inner air spring chamber 50B is compressed, and the pressure in the second inner air spring chamber 50B increases.

  When the rotating member 55 rotates counterclockwise, the adjusting rod 56 retracts upward with respect to the inner air spring chamber 50. The piston 57 moves from the second inner air spring chamber 50B toward the first inner air spring chamber 50A while the upper surface of the ring member 62 abuts against the lower surface near the inner periphery of the piston 57. When the piston 57 moves in the direction of the first inner air spring chamber 50A, the pressure of the second inner air spring chamber 50B acting in the direction of the first inner air spring chamber 50A is also applied to the piston 57. As the piston 57 moves in the direction of the first inner air spring chamber 50A, the second inner air spring chamber 50B is expanded and the pressure in the second inner air spring chamber 50B decreases.

  As shown in FIG. 2, the first front fork 10 includes an inward seal member 51 and an outward seal member in order from the top along the axial direction of the piston 23 on the outer periphery of the piston 23 provided on the piston rod 22. 71 and a piston ring 24 are provided. The outward seal member 71 includes a first outward seal member 71 </ b> A and a second outward seal member 71 </ b> B, and the first outward seal member 71 </ b> A and the second outward seal member 71 </ b> B are the outer periphery of the piston 23. Are provided at two positions in the axial direction. The inward seal member 51, the first outward seal member 71 </ b> A, the second outward seal member 71 </ b> B, and the piston ring 24 are loaded in annular grooves provided at four positions in the axial direction on the outer periphery of the piston 23. Yes. The outward seal member 71 may be composed of three outward seal members, or may be composed of one outward seal member. Further, the inward seal member 51 may be composed of two or more inward seal members.

  The inward seal member 51 has a lip L that is in sliding contact with the inner peripheral surface of the guide cylinder 21 facing the inner air spring chamber 50 that is the upper side. The first outward seal member 71 </ b> A and the second outward seal member 71 </ b> B have the lip L that is in sliding contact with the inner peripheral surface of the guide cylinder 21 facing the rebound air spring chamber 70 that is below.

  As shown in FIG. 3, the first front fork 10 detects the pressure in the first inner air spring chamber 50A, and detects the pressure in the first inner air spring chamber 50B. 2 detection units 42B. The first detector 42A is provided so as to be exposed inside the first inner air spring chamber 50A, and detects the pressure in the first inner air spring chamber 50A. The first detection unit 42A is provided on the bottom surface of the fork bolt 31, for example. The second detector 42B is provided so as to be exposed inside the second inner air spring chamber 50B, and detects the pressure in the second inner air spring chamber 50B. The second detection unit 42B is provided, for example, on the bottom surface of the second adjustment rod unit 56B. The first detection unit 42A and the second detection unit 42B are composed of, for example, an electronic semiconductor pressure sensor. The first detection part 42A and the second detection part 42B provided on the first front fork 10 are installed outside the first front fork 10 via a wiring (not shown) provided in the fork bolt 31. Connected to a display (not shown).

  Then, rotation is performed based on the pressure in the first inner air spring chamber 50A and the pressure in the second inner air spring chamber 50B detected by the first detector 42A and the second detector 42B displayed on the display. The second inner air spring chamber 50B is expanded or compressed by rotating the member 55 to set the adjustment rod 56 in the guide cylinder 21 to a predetermined length and moving the piston 57 in the vertical direction. The pressure in the first inner air spring chamber 50A and the pressure in the second inner air spring chamber 50B can be adjusted as appropriate.

  The upper part of the outer air spring chamber 60 has a seal member 61 </ b> A of the cap 30 provided on the inner peripheral surface of the vehicle body side tube 11 and a seal of the fork bolt 31 provided on the inner peripheral surface of the cap 30. The member 61B is hermetically sealed. The lower part of the outer air spring chamber 60 includes a seal member 63A of the bottom piece 33 provided on the inner peripheral surface of the axle tube 12 and a seal member 63B of the bottom piece 33 provided on the bottom surface of the axle bracket 32. And the sealing members 64 </ b> A and 64 </ b> B of the bottom bolt 34 provided on the inner peripheral surface of the axle bracket 32. Further, the outer air spring chamber 60 is hermetically sealed by a seal member 65 of a rod guide 36 provided on the outer peripheral surface of the piston rod 22.

  The pressure in the outer air spring chamber 60 is adjusted by an outer pressure adjusting unit 67 shown in FIG. The outer pressure adjusting portion 67 is configured by an air valve attached at a position facing the outside of the fork bolt 31. The outer pressure adjusting portion 67 communicates with the outer air spring chamber 60 via a flow path (not shown) provided in the fork bolt 31. Moreover, the outer side pressure adjustment part 67 is provided with the rubber film part which can pierce the injection needle of a pressure injector, for example. For example, by inserting a dedicated device through the rubber film portion of the outer pressure adjusting portion 67 and injecting air into the outer pressure adjusting portion 67 or exhausting air from the outer pressure adjusting portion 67, The pressure of the pressure adjusting unit 67 is adjusted.

  As shown in FIG. 2, the rebound air spring chamber 70 includes a seal member 71 of the piston 23 provided on the inner peripheral surface of the guide cylinder 21 and a rod provided on the outer peripheral surface of the piston rod 22. The seal member 72 of the guide 36 and the seal member 73 of the rod guide 36 provided on the inner peripheral surface of the guide cylinder 21 are hermetically sealed. Further, the rebound air spring chamber 70 is hermetically sealed by a seal member of the piston rod 22 provided on the inner peripheral surface of the bottom bolt 34.

  As shown in FIG. 2, the first front fork 10 is provided with a sub tank 80 having an air chamber 81 communicating with the rebound air spring chamber 70 outside the vehicle body side tube 11 and the axle side tube 12. The sub tank 80 is integrally formed with the fitting portion 32 </ b> A of the axle bracket 32 that is screwed to the lower end portion of the axle side tube 12.

  The sub tank 80 has an air chamber 81 in which a vertical chamber 81A and a horizontal chamber 81B are combined in an L shape. A cap 82 is provided in the opening facing the upper side of the vertical chamber 81A via a seal member, and the vertical chamber 81A is sealed. An adjuster bolt 91 of a volume adjusting device 90 to be described later is provided at the center of the cap 82 via a seal member. A plug bolt is provided through a seal member at the opening facing the side of the side chamber 81B, and the side chamber 81B is sealed.

  The sub tank 80 includes a communication port (not shown) that is orthogonal to the axial direction of the horizontal chamber 81B and is disposed on the inner peripheral surface of the bottom of the horizontal chamber 81B. This communication port is open to a bolt insertion hole 32 </ b> C through which the head 34 </ b> H of the bottom bolt 34 in the axle bracket 32 is inserted.

  Further, the bottom bolt 34 includes a bottomed center hole 34A that communicates with the lower end of the hollow portion 22A of the piston rod 22 at the center, and includes a plurality of radiation holes 34B that extend in the radial direction from the center hole 34A. The outer peripheral portion is provided with an annular groove 34C communicating with the opening at the outer end of the radiation hole 34B. The communication port of the sub tank 80 communicates with the annular groove 34 </ b> C of the bottom bolt 34. In bolt insertion holes 32C of the axle bracket 32 through which the head 34H of the bottom bolt 34 is inserted, seal members 64A and 64B are sealed at the upper and lower portions of the annular groove 34C. The upper end portion of the hollow portion 22A of the piston rod 22 is communicated with the rebound air spring chamber 70 through a communication hole 23A formed in the piston 23 of the piston rod 22.

  In the first front fork 10 configured as described above, the air chamber 81 of the sub tank 80 includes the communication port of the sub tank 80, the annular groove 34C of the bottom bolt 34, the radiation hole 34B, the center hole 34A, and the hollow of the piston rod 22. The rebound air spring chamber 70 communicates with the portion 22 </ b> A and the communication hole 23 </ b> A of the piston 23. The communication port, the annular groove 34C, the radiation hole 34B, the center hole 34A, and the communication hole 23A have a passage area equal to or larger than the hollow portion 22A of the piston rod 22.

  The volume adjusting device 90 provided in the sub tank 80 is provided with an adjuster bolt 91 inserted in the center of the cap 82 by a seal member, and seals the air chamber 81. The adjuster bolt 91 is provided with an upward operation grip projecting to the outer periphery at the upper end facing the outside, and a piston (not shown) inserted through a seal member at the tip of the adjuster bolt 91 inserted into the air chamber 81. Prepare. This piston is fixed by a retaining ring and includes a seal member that is in sliding contact with the inner peripheral surface of the vertical chamber 81A. An air supply / exhaust valve (not shown) is provided in the central hole of the adjuster bolt 91 via a seal member, and the air chamber 81 is sealed. A valve cover that covers the air supply / exhaust valve is provided at a central opening of the adjuster bolt 91 via a seal member. The valve cover includes rotation operation grooves that are radially engraved around the center of the outer surface.

  The volume adjusting device 90 can adjust the volume of the air chamber 81 by screwing the adjuster bolt 91 to advance and retract the piston. Further, the volume adjusting device 90 can adjust by supplying and discharging the pressure of the air chamber 81 using an air supply / exhaust valve.

  Further, the first front fork 10 includes an oil chamber filled with lubricating oil in order to lubricate the sliding portions of the vehicle body side tube 11 and the axle side tube 12 and the sliding portions of the guide cylinder 21 and the piston rod 22. ing. The lubricating oil mixes with the air in the first front fork and exhibits a lubricating function.

In the pressure side stroke of the first front fork 10, the piston rod 22 slides in the direction of insertion into the guide cylinder 21. The first front fork 10 forms an air spring by the inner air spring chamber 50 and the outer air spring chamber 60 that are compressed in the compression side stroke. The spring force F ₂ of the air spring of the inner air spring chamber the spring force of the air spring of 50 F ₁ and the outer air spring chamber 60 urges in a direction to extend the vehicle body side tube 11 and the axle side tube 12.

In the extension side stroke of the first front fork 10, the piston rod 22 slides in the direction of retreating from the guide cylinder 21. The first front fork 10 forms an air spring by the rebound air spring chamber 70 compressed in the extension side stroke. The spring force F ₃ of the air spring of the rebound air spring chamber 70 is urged by the spring forces F ₁ and F ₂ of the air springs of the inner air spring chamber 50 and the outer air spring chamber 60 of the vehicle body side tube 11 and the axle side tube 12. after being in a direction to shrink the vehicle body side tube 11 and the axle side tube 12 against the spring force F ₁ of the air spring of the inner air spring chamber 50 and the spring force F ₂ of the air spring of the outer air spring chamber 60 Energize.

The front fork 1 includes the spring force F ₁ of the air spring of the inner air spring chamber 50 and the outer side that urges the vehicle body side tube 11 and the axle side tube 12 in the extending direction of the first front fork 10. a spring force F ₂ of the air spring of the air spring chamber 60, is the sum of the spring force F ₃ of the air spring of the rebound air spring chamber 70 for biasing in a direction to contract the vehicle body side tube 11 and the axle side tube 12 synthesis A spring force F (F ₁ + F ₂ + F ₃ ) is generated.

  In the front fork 1 configured as described above, the compression rate of the first front fork 10 during the pressure side stroke depends on the pressure of the second inner air spring chamber 50B. By rotating the rotating member 55 and moving the piston 57 in the direction of the piston 23, the second inner air spring chamber 50B is compressed. Then, the compression of the second inner air spring chamber 50B increases the pressure in the second inner air spring chamber 50B, so that the compression ratio of the first front fork 10 during the compression stroke is reduced. Bottoming can be suppressed by reducing the compression ratio of the first front fork 10. Furthermore, the compression ratio of the first front fork 10 is a numerical value of the first inner air spring chamber 50A and the second inner air spring chamber 50B detected by the first detector 42A and the second detector 42B. It can be easily controlled by rotating the rotating member 55 provided outside the front fork while looking at the display that displays. This eliminates the need for the work related to oil injection into the spring legs, which has been conventionally performed to adjust the compression ratio of the spring legs, and the compression ratio of the spring legs is easy, short, and not restricted by the work environment. Can be adjusted.

Further, the first front fork 10 forms an air spring by the inner air spring chamber 50 and the outer air spring chamber 60 that are compressed in the compression side stroke. The spring force F ₂ of the air spring of the inner air spring chamber 50 of the air spring the spring force F ₁ and the outer air spring chamber 60 urges in a direction to extend the vehicle body side tube 11 and the axle side tube 12. Further, the first front fork 10 forms an air spring by the rebound air spring chamber 70 which is compressed in the extension side stroke. The spring force F ₃ of the air spring in the rebound air spring chamber 70 is biased in a direction in which the vehicle body side tube 11 and the axle side tube 12 are contracted against the spring force F ₁ of the air spring in the inner air spring chamber 50. Accordingly, the spring force F ₁ of the air spring of the inner air spring chamber 50 and the outer air spring chamber that urge the vehicle body side tube 11 and the axle side tube 12 in the direction of extending the expansion stroke of the first front fork 10. The combined spring force F ₂ is the sum of the spring force F ₂ of the air spring 60 and the spring force F ₃ of the air spring of the rebound air spring chamber 70 that biases the vehicle body side tube 11 and the axle side tube 12 in the contracting direction. Is produced.

  In the first front fork 10 constituting the front fork 1 of the above-described embodiment, it has been described that the rotating member 55 is rotated clockwise to move the piston 57 in the direction of the second inner air spring chamber 50B. However, the rotation member 55 may be rotated counterclockwise to move the piston 57 in the direction of the second inner air spring chamber 50B. Further, in the first front fork 10 constituting the front fork 1 of the above-described embodiment, the rotation member 55 is rotated counterclockwise to move the piston 57 in the direction of the first inner air spring chamber 50A. However, the rotation member 55 may be rotated clockwise to move the piston 57 in the direction of the first inner air spring chamber 50A.

  In the first front fork 10 constituting the front fork 1 of the above-described embodiment, as a mechanism for adjusting the pressure in the first inner air spring chamber 50A and the second inner air spring chamber 50B, a rotating member 55, an adjustment The mechanism including the rod 56, the piston 57, and the ring member 62 has been described. If the first inner air spring chamber 50A and the second inner air spring chamber 50B can be adjusted to desired pressures, the structure of the mechanism is as follows. It is not limited.

  In the first front fork 10 constituting the front fork 1 of the above-described embodiment, it has been described that the axle side tube 12 is slidably inserted into the inner peripheral surface of the vehicle body side tube 11. The tube 11 may be slidably inserted into the inner peripheral surface of the axle tube 12.

  In the first front fork 10 constituting the front fork 1 of the above-described embodiment, the vehicle body side tube 11 includes the guide cylinder 21 provided with the rod guide 36, and the axle side tube 12 includes the piston 23 provided with the piston 23. Although it has been described that the rod 22 is provided, the vehicle body side tube 11 may include the piston rod 22 provided with the piston 23, and the axle side tube 12 may include the guide cylinder 21 provided with the rod guide 36. When the vehicle body side tube 11 includes the piston rod 22 and the axle side tube 12 includes the guide cylinder 21, the configuration provided in the first front fork 10 is appropriately disposed upside down.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

  DESCRIPTION OF SYMBOLS 1 ... Front fork, 2 ... Motorcycle, 3 ... Body frame, 4 ... Head pipe, 5 ... Axle, 6A ... Front wheel, 6B ... Rear wheel, 7 ... Handle, 8 ... Swing arm, 9 ... Rear suspension, 9A ... No. DESCRIPTION OF SYMBOLS 1 Rear suspension, 10 ... 1st front fork, 11 ... Car body side tube, 12 ... Axle side tube, 13A, 13B ... Bush, 13C ... Seal member, 21 ... Guide cylinder, 21L ... Lower cylinder, 21S ... Seal member 21U: Upper cylinder, 22: Piston rod, 22A: Hollow part, 23 ... Piston, 23A ... Communication hole, 24 ... Piston ring, 25 ... Stabilizing collar, 30 ... Cap, 31 ... Fork bolt, 32 ... Axle bracket, 32A ... Fitting portion, 32B ... Axle support hole, 32C ... Bolt insertion hole, 33 ... Bottom piece, 34 ... Bottom bolt 34A ... Center hole 34B ... Radiation hole 34C ... Annular groove 34H ... Head, 35 ... Lock nut 36 ... Rod guide 37 ... Bush 40 ... Suspension spring 42A ... First detector 42B 2nd detector, 50 ... inner air spring chamber, 50A ... first inner air spring chamber, 50B ... second inner air spring chamber, 51, 52, 53 ... seal member, 54 ... cover, 54A ... screw , 54B ... opening, 55 ... rotating member, 55A ... threaded part, 56 ... adjusting rod, 56A ... first adjusting rod part, 56B ... second adjusting rod part, 57 ... piston, 57A ... inner peripheral recess, 57B ... Outer peripheral annular groove, 58 ... inner seal member, 59 ... outer seal member, 60 ... outer air spring chamber, 61A, 61B ... seal member, 62 ... ring member, 63A, 63B ... seal member, 64A, 6 B ... Seal member, 65 ... Seal member, 67 ... Outer pressure adjusting part, 70 ... Rebound air spring chamber, 71 ... Outward seal member, 71A ... First outward seal member, 71B ... Second outward seal member 72 ... Seal member, 72A ... Seal presser, 72B ... Rubber stopper, 73 ... Seal member, 80 ... Sub tank, 81 ... Air chamber, 81A ... Vertical chamber, 81B ... Horizontal chamber, 82 ... Cap, 90 ... Volume adjusting device, 91: Adjuster bolt.

Claims (5)

A front fork comprising a pair of first legs and second legs,
At least one of the first leg and the second leg is
A vehicle body side tube provided on the vehicle body side, closed at the upper end side and opened at the lower end side;
An axle side tube provided on the axle side, having an upper end side opened, a lower end side closed, connected to the vehicle body side tube, and relatively moved along an axial direction of the vehicle body side tube with respect to the vehicle body side tube; ,
A guide cylinder extending along the axial direction, with an upper end attached to the upper end of the vehicle body side tube and closed, and a lower end opened;
A cylindrical shape that extends along the axial direction, has a lower end attached to the lower end side of the axle-side tube, has an upper end opened, and moves relative to the guide cylinder along the axial direction. Piston rod,
A rod guide provided at an opening of the guide cylinder and slidably supporting the piston rod;
A first piston which is provided while maintaining an opening in the opening of the piston rod, and is slidably inserted into the guide cylinder;
An adjustment rod that is attached to the upper end portion side of the guide cylinder, is provided so as to be expandable and contractable along the axial direction in the guide cylinder, and is set to a predetermined length;
A second piston provided at a lower end portion of the adjustment rod, which divides a space in the guide cylinder above the first piston into a first chamber and a second chamber below the first chamber ; With
At least one of the first leg and the second leg further comprises:
A first detector for detecting the pressure in the first chamber;
A second detector for detecting the pressure in the second chamber;
A front fork comprising: A front fork comprising a pair of first legs and second legs,
At least one of the first leg and the second leg is
A vehicle body side tube provided on the vehicle body side, closed at the upper end side and opened at the lower end side;
An axle side tube provided on the axle side, having an upper end side opened, a lower end side closed, connected to the vehicle body side tube, and relatively moved along an axial direction of the vehicle body side tube with respect to the vehicle body side tube; ,
A piston rod extending along the axial direction, with an upper end attached to the upper end of the vehicle body side tube, and a lower end opened;
Extending along the axial direction, the lower end is attached to the lower end of the axle side tube and closed, the upper end opens, and moves relative to the piston rod along the axial direction. A cylindrical guide cylinder,
A rod guide provided at an opening of the guide cylinder and slidably supporting the piston rod;
A first piston which is provided while maintaining an opening in the opening of the piston rod, and is slidably inserted into the guide cylinder;
An adjustment rod attached to the lower end side of the guide cylinder and extending and contracting along the axial direction in the guide cylinder and set to a predetermined length;
A second piston that is provided at an upper end portion of the adjustment rod and divides a space in the guide cylinder below the first piston into a first chamber and a second chamber above the first chamber ; With
At least one of the first leg and the second leg further comprises:
A first detector for detecting the pressure in the first chamber;
A second detector for detecting the pressure in the second chamber;
A front fork comprising:   The front fork according to claim 1 or 2, wherein the pressure in the second chamber is increased by moving the second piston in the direction of the second chamber.   The front fork according to any one of claims 1 to 3, wherein the pressure in the second chamber is lowered by moving the second piston in the direction of the first chamber. At least one of the first leg and the second leg further comprises:
A third chamber formed between the vehicle body side tube and the axle side tube, the guide cylinder and the piston rod;
5. The apparatus according to claim 1, further comprising a fourth chamber formed between the rod guide provided in the guide cylinder and the first piston provided in the piston rod. The front fork described in the section.

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