JP2015197117A - front fork - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a front fork, in which an excessive pressure is not applied to a buffer chamber thereby to suppress the deterioration of a piston outer circumference and to acquire desired reaction characteristics.SOLUTION: A front fork comprises: a buffer chamber B, in which a piston 3 is slidably accommodated; a ring-shaped outer buffer chamber M positioned on the outer circumference side of that buffer chamber B; and a ring piston member 14 accommodated in that outer buffer chamber M, where the ring piston member 14 is constituted of a ring body 15 for hermetically sliding between the inner circumference and the outer circumference of the outer buffer chamber M, and where a slide member 41 is pushed toward a compression chamber 17A by the ring body 15 at the time when the ring body 15 descends by a predetermined distance.

Description

  The present invention relates to a front fork, and more particularly, to an air spring type front fork.

Conventionally, an air spring type device disclosed in Patent Document 1 is known as a shock absorber for a motorcycle. In this case, the casing is partitioned into two upper and lower buffer chambers by a piston. According to this, the air on the one buffer chamber side is compressed by the pressing force of the piston, and at this time, the air on the other buffer chamber side is in a negative pressure state, so that a buffer force is obtained as a result.
However, when the air on one buffer chamber side is compressed, a large internal pressure is repeatedly generated on the buffer chamber side, and this internal pressure is repeatedly applied to a sealing member such as an air packing normally provided on the outer periphery of the piston. It has the possibility of incurring durability deterioration of the sealing member, and has the possibility of causing the buffer performance deterioration. In addition, the reaction force characteristics are unambiguous due to the structure in which the reaction force is obtained by simply pressing the air on the buffer chamber side of one predetermined volume with the piston in the compression side stroke, and the weight of the vehicle body is large and small. There was a drawback that it was not easy to obtain reaction force characteristics corresponding to running performance.

Japanese Examined Patent Publication No. 4-27413

  The present invention has been made in view of these problems, and prevents deterioration of piston performance so that excessive pressure is not applied to the buffer chamber, and in addition, makes it possible to adjust the reaction force characteristic in the compression side stroke. Objective.

  As a configuration of a front fork according to the present invention for solving the above-mentioned problems, a holder member provided on a wheel side, a long inner cylinder protruding from the holder member and forming a buffer chamber, and an upper end of the inner cylinder A rod guide provided on the rod, a piston attached to the rod and accommodated in the inner cylinder, an outer cylinder projecting from the holder member so as to form a gap between the outer periphery of the inner cylinder, and the outer It protrudes from the holder member so as to form an outer buffer chamber consisting of a space of a constant interval with the outer periphery of the cylinder, and the outermost cylinder that is longer than the inner cylinder and the outer cylinder, A sliding cylinder that protrudes from the vehicle body side toward the holder member and slides on the outer periphery of the outermost cylinder; and A cap member on the vehicle body side that seals the end opening and holds one end of the rod; a holding cylinder that protrudes from the cap member and is positioned between the inner periphery of the outermost cylinder and the outer periphery of the outer cylinder; A front fork having a ring piston member held on the tip side of the holding cylinder, wherein the ring piston slides on the outer periphery or the inner periphery of the outer buffer chamber or both in an airtight manner. The outer buffer chamber is divided into an upper space and a lower space by the ring body, and an air flow path that connects the upper space and the lower space is provided in the ring body, and an inner periphery of the lower space is provided. And a ring-shaped sliding member that is in close contact with the outer periphery and a pressurizing chamber that is pressurized by the sliding member, and a regulating means that regulates the distance of the sliding member to the rod guide at a fixed position. And a configuration allowing pushing the sliding member in the pressure chamber direction by the ring member. With this configuration, in the compression side stroke, the sliding member is pressed from the time when the ring body slides for a certain length so that the pressure chamber is pressurized and a reaction force is generated. Desired reaction force characteristics can be obtained by adjusting the pressure in the pressurizing chamber.

  Further, as another configuration of the front fork according to the present invention, the air flow path is formed on the inner periphery of the ring body and includes a concave groove extending in the upper space and lower space directions. With this structure, the ring body can be lowered in the pressure side direction without any trouble by air ventilation through the air flow path, and the extension side stroke can be easily performed.

  As another configuration, the sliding member has a seal member that is fitted in a concave groove provided on the inner and outer circumferences of the sliding member. Can be pressurized.

  Further, as another configuration, the restriction means has a simple configuration because one end side is attached to the rod guide, and the other end side is formed of a cylindrical body having a predetermined length extending beyond the ring body toward the sliding member. The position of the sliding member can be regulated.

It is sectional drawing of a front fork. It is a principal part expanded sectional view of a front fork. It is a principal part perspective view of a front fork.

FIG. 1 is a sectional view showing an embodiment of a front fork according to the present invention. In the figure, reference numeral 1 denotes a holder member attached to the axle side. The holder member 1 has a fastening bolt 1b for fastening the axle penetrating through the axle attachment hole 1a. A cylindrical air chamber 1c having a capacity and a plug portion 1d for sealing the air chamber 1c are provided. The plug portion 1d is provided with a valve 1k that allows air to enter and exit from the air chamber 1c. The air that enters and exits through the valve 1k allows the air to enter and exit from the inside of the front fork main body S, which will be described later, together with the air chamber 1c through a tube 1j connected to a tube holding portion 1f attached to the plug portion 1d. Composed.
Further, on the side portion, the brake caliper mounting portion 1i and the vehicle speed sensor mounting portions 1t and 27 are formed in a pair of upper and lower so as to protrude from the side portion of the holder member 1 and cover and protect a part of the outer periphery of the wheel. It includes a fender mounting part for fixing. Note that 1y is a split part.
A stretchable longitudinal front fork main body S is held between the holder member 1 and the vehicle body.

  In the center of the front fork body S, a rod 2 made of a thin cylindrical body is located. The distal end side of the rod 2 is inserted through an opening of a cylinder 4 described later. A piston 3 is fixed to the tip of the rod 2. The cylinder 4 has a lower portion fixed to the holder member 1 in a sealed state, and a tip end projecting upward to form a space for accommodating the piston 3. The piston 3 is operated by a rod 2 provided at the upper part so as to slide up and down on the inner periphery of the cylinder 4.

  As shown in FIG. 2, the piston 3 has a hole 3 a that opens in the direction of the holder member 1 (axle direction) in the lower part, and ring grooves 3 b and 3 c that are provided adjacent to each other in the vertical direction on the outer periphery. A ring seal 3d is fitted in the ring grooves 3b and 3c, and the outer periphery of the piston 3 slides in the vertical direction while maintaining airtightness with the inner periphery of the cylinder 4.

  On the upper surface of the top portion 3e of the piston 3, a tapered convex portion 3h whose outer periphery is tapered toward the upper side is formed. On the top 3e side of the protrusion 3h, an opening 3f that penetrates in the diameter direction of the protrusion 3h and opens to the side of the protrusion 3h is provided in a cross shape. Further, the convex portion 3h is provided with a rod attachment hole 3k for extending in the vertical direction from the upper end to the middle portion and for attaching the piston 3 to the lower end side of the rod 2. The inner periphery of the rod mounting hole 3k is formed as a screw hole for fixing the piston 3 by screwing the outer periphery on the lower end side of the rod 2 described above. The bottom of the rod mounting hole 3k is provided with a hole 3g communicating with the opening hole 3f. Therefore, in the state where the piston 3 is attached, the through hole 2a of the rod 2 has a hole 3g, an opening hole 3f opened from the side of the convex portion 3h, a space 2b on the outer periphery of the spring 25 described later, and a hole 4b at the upper end of the cylinder 4. Is communicated with a gap 5 between an outer periphery 4a of the cylinder 4 and an inner periphery 7b of an outer cylinder 7 described later. The outer periphery of the convex portion 3h functions as a spring seat 3m on which a spring 25 described later is seated.

The bottom of the cylinder 4, that is, the holder member 1 side, is airtightly fixed by a ring-shaped cylinder mounting frame 1g. The air chamber 1c is formed so as to be parallel to the cylinder 4 by machining a part of the holder member 1, and is connected to the inside of the cylinder 4 via a communication path 1h formed below the cylinder mounting frame 1g. Communicate. A buffer chamber B is formed by a space 31 surrounded by the air chamber 1 c and the holder member 1 in the cylinder 4 below the piston 3. An oil inlet / outlet valve 1 u made of, for example, a one-touch coupler that allows oil to flow into and out of the space 31 is attached to the communication path 1 h so as to be exposed to the outside of the holder member 1. The volume of the buffer chamber B can be adjusted by injecting incompressible oil into the buffer chamber B through the oil inlet / outlet valve 1u.
Further, the other end of the tube 1j whose one end is connected to the plug portion 1d of the air chamber 1c is inserted so as to be positioned at a predetermined height inside the cylinder 4 via the air chamber 1c and the communication passage 1h. This tube 1j is provided to prevent oil injected into the buffer chamber B from the oil inlet / outlet valve 1u to change the volume in the buffer chamber B from being discharged when adjusting the air pressure in the buffer chamber B. It has been.
In addition, 1m is an O-ring. The cylinder 4 has a length that extends from the holder member 1 side to the vicinity of the center of the entire length of the front fork main body S that is the longest in the extension stroke.

The holder member 1 is provided with a holding cylinder 1n that protrudes upward as an inclined surface 1o whose inner circumference gradually increases in diameter in the upward direction, and at the bottom of the inner circumference of the holding cylinder 1n, the root of the outer cylinder 7 is provided. A side outer periphery is fitted. The outer cylinder 7 is coaxial with the cylinder 4, and the inner periphery 7 b extends upward while maintaining a gap 5 with the outer periphery 4 a of the cylinder 4. That is, the cylinder 4 is an inner cylinder located on the inner peripheral side of the outer cylinder 7.
On the inner periphery of the holder member 1 below the lower end of the outer cylinder 7, a hole 1 w extends from a part of the ring groove 43 formed in a ring shape to the side surface of the holder member 1. An oil inlet / outlet valve 1v made of, for example, a one-touch coupler is attached to the hole 1w so as to be exposed to the outside of the holder member 1. As a result, oil can be injected and discharged from the oil inlet / outlet valve 1v through the hole 1w and the ring groove 43 into the gap 5 and the inner buffer chamber Z described later, and incompressible oil is injected into the inner buffer chamber Z. Thus, the volume of the inner buffer chamber Z can be adjusted.

  Further, the inner circumference of the outermost cylinder 9 is fitted on the outer circumference of the holding cylinder 1n so as to form a space 8 having a constant gap with the outer circumference 7a of the outer cylinder 7. The space 8 forms the outer buffer chamber M of the present application. In addition, 1q is an O-ring and 1z is a thread part. In this case, the outer cylinder 7 extends slightly above the cylinder 4, but the outermost cylinder 9 is set to be considerably longer than the cylinder 4 and the outer cylinder 7.

  11 is a sliding cylinder having a diameter larger than that of the outermost cylinder 9, and the sliding cylinder 11 extends from the cap member 12 side on the vehicle body side toward the holder member 1 so as to surround the outer periphery 9 a of the outermost cylinder 9. . Bearings 11a and 11b that support each other slidably while maintaining a sealed state with the outermost cylinder 9 are provided on the inner circumference of the sliding cylinder 11 on the upper side and the lower side, respectively. Thereby, the outermost cylinder 9 as an axle side tube attached to the holder member 1 and the sliding cylinder 11 as a body side tube attached to the vehicle body side are configured to be slidable with respect to each other. In addition, a sealing member 10 that maintains airtightness with the outer periphery 9 a of the outermost cylinder 9 is provided on the inner periphery on the front end side of the sliding cylinder 11.

  The upper end opening of the sliding cylinder 11 is sealed with the cap member 12. On the outer peripheral side of the cylindrical base portion 12 a on the upper side of the cap member 12, a screw portion 12 b that is screwed onto the upper inner periphery of the sliding tube 11 and an O-ring 12 c as a sealing member are provided. The lower side of the base 12a is narrowed to a small diameter, and the upper outer periphery of the rod holder 12e is screwed to the inner periphery of the small diameter cylinder 12d. The outer periphery of the upper end of the rod 2 is screwed to the inner periphery of the lower portion of the rod holder 12e via the screw portion 12y, and the rod 2 extends from the cap member 12 side toward the holder member 1. A hat-shaped holding body 12f is attached between the lower end of the small diameter cylinder 12d and the flange 12x of the rod holding body 12e, and the inner circumference of the upper end side of the holding cylinder 13 is screwed to the outer periphery of the holding body 12f. Is done. Accordingly, the holding cylinder 13 extends in the direction of the holder member 1 from the cap member 12 side while maintaining the same axis as the rod 2. The holding cylinder 13 is formed with a long hole 13m for weight reduction, and its lower end is dimensioned to extend to substantially the same position as the piston 3.

  Further, the cap member 12 communicates with the inner circumferential space (through hole 2a) of the rod 2, and a valve 12v for injecting air into the inner buffer chamber Z described later, and air into the outer buffer chamber M described later. A valve 12w for injecting is provided so that the air pressure in the inner buffer chamber Z and the air pressure in the outer buffer chamber M can be adjusted.

Reference numeral 6 denotes a rod guide, which has a cylindrical body 6b protruding downward from the outer peripheral side of the cylindrical upper base 6a. The rod guide 6 is attached to the outer cylinder 7 by screwing the outer periphery of the cylindrical body 6b to the inner periphery of the upper end of the outer cylinder 7, and the airtightness with the outer cylinder 7 is maintained by a sealing member provided on the outer periphery. . When the rod guide 6 is attached to the outer cylinder 7, the lower end of the cylindrical body 6b comes into contact with the upper end of the cylinder 4 to support the cylinder 4 from the upper end side. Further, on the inner peripheral side of the cylindrical body 6b, a seal holding cylinder 6d having a ring-shaped partition piece 6c through which the rod 2 passes is provided at the inner peripheral center. Ring-shaped sealing materials 6s are fitted in the upper and lower ring-shaped grooves of the partition piece 6c on the inner peripheral side of the seal holding cylinder 6d, with the sealing directions opposite to each other. As a result, the rod 2 is slidable in the vertical direction while being kept airtight by the sealing material 6s. In this manner, the rod guide 6 is attached so as to maintain an airtight state with the outer cylinder 7 and the rod 2, and thus a space formed by the gap 5 formed by the inner periphery of the outer cylinder 7 and the outer periphery of the cylinder 4, The space formed by the through hole 2a of the rod 2 and the space formed by the space 2b in which the spring 25 is accommodated constitute one air chamber, which is formed as an inner buffer chamber Z in the buffering operation of the front fork main body S.
A seal stopper piece 6e for holding the lower seal material 6s is provided on the opening end face of the lower part of the seal holding cylinder 6d. On the lower surface side of the seal stopper piece 6e, a spring seat 6f that is paired with a spring seat 3m formed on the outer periphery of the convex portion 3h of the piston 3 is provided.

Two springs 25; 25 are provided between the spring seat 6f and the spring seat 3m. A ring-shaped pedestal 6m is provided between the upper spring 25 and the lower spring 25, thereby holding the inner circumference of the upper and lower springs 25 and preventing the upper and lower springs 25 from being deformed.
The upper end of the upper spring 25 is attached to the spring seat 6f, and the lower end of the lower spring 25 is attached to the spring seat 3m. Thereby, as the piston 3 moves in the direction of the cap member 12 (upward), the spring 25 is gradually compressed and functions as a rebound spring that biases the force in a direction to push the piston 3 downward. A stopper 2g is positioned on the outer periphery of the rod 2 at a predetermined position. The stopper 2g is held on the lower surface of the stopper 2m screwed to the outer periphery of the fixing tool 2n. When the rod 2 slides downward, the stopper 2g comes into contact with the upper end of the rod guide 6 when the piston 3 moves to a certain position, thereby moving the piston 3, the rod 2 and the holding cylinder 13 downward. Has the function of regulating.

2 and 3, a ring piston member 14 is provided on the lower end side of the holding cylinder 13. The ring piston member 14 includes a ring body 15 that divides a space 8 between an outer periphery 7 a of the outer cylinder 7 and an inner periphery 9 b of the outermost cylinder 9 into an upper space 16 and a lower space 17. The ring body 15 has a threaded portion 15x that is screwed into the inner periphery on the front end side of the holding cylinder 13. The ring body 15 has a lower end protruding from the lower end of the holding cylinder 13, and a seal member on the outer periphery of the protruding portion. 15e. Thereby, the ring body 15 slides up and down along the inner circumference of the outermost cylinder 9 while maintaining the same positional relationship as the piston 3 by the vertical movement of the holding cylinder 13.
The ring body 15 of the ring piston member 14 is provided with an air flow path 40 that communicates the upper space 16 and the lower space 17. For example, the air flow path 40 is formed by forming a concave groove 40 a extending from the upper space 16 toward the lower space 17 on the inner periphery of the ring body 15.

The lower space 17 is provided with a ring-shaped sliding member 41 that is in close contact with the inner periphery and the outer periphery of the lower space 17. The sliding member 41 has a seal member 41c fitted into ring-shaped concave grooves 41a and 41b provided on the inner and outer circumferences, and divides the lower space 17 in the vertical direction and in the lower space 17 in the vertical direction. It functions as a free piston that can be moved.
The sliding member 41 is regulated so that the dimension to the lower end of the rod guide 6 is a distance L by abutting against the tip of the regulating means 42 made of a cylindrical body. The regulating means 42 is attached to the rod guide 6 at one end, and the other end faces the holder member 1 so that the outer side of the outer cylinder 7 extends along the axis of the outer cylinder 7 to the sliding member 41 beyond the ring body 15. It consists of a cylinder that extends. A lower portion of the lower space 17 is partitioned by the sliding member 41 as a pressure chamber 17A. Air from an air valve 1A provided on the holder member 1 side is sent to the pressure chamber 17A through the communication path 1N on the inner peripheral side of the holding cylinder 1n, and the internal pressure is set to a predetermined magnitude. The air valve 1A has an opening / closing plug, and air is injected into the pressure chamber 17A via the communication path 1N by injecting air while pressing the opening / closing plug from an air injection tool (not shown) to open the pressure chamber. The pressure of 17A can be set to a predetermined value. The sliding member 41 is always pressed upward by this pressure (air spring force). The pressure of the air in the pressure chamber 17A is set so that, for example, the sliding member 41 comes into contact with the tip of the regulating means 42.

In the above configuration, an inner buffer chamber Z is formed in the front fork main body S by the space formed by the inner periphery of the through hole 2 a of the rod 2, the space 2 b, and the gap 5. A buffer chamber B is formed by the space 31 and the air chamber 1 c, and the outer buffer chamber is formed by the ring-shaped space 8 between the outer cylinder 7 and the outermost cylinder 9 and the space between the sliding cylinder 11 and the outer cylinder 7. M is formed. Further, the outer buffer chamber M is formed in a pressure chamber 17A partitioned on the lower side of the sliding member 41 and a pressure chamber upper chamber 17B.
That is, in the front fork main body S, four air spring chambers of the inner buffer chamber Z, the buffer chamber B, the pressure chamber 17A, and the pressure chamber upper chamber 17B are formed. Among these four chambers, the buffer chamber B, the pressure chamber 17A, and the pressure chamber upper chamber 17B mainly exert an air spring force in the extending direction of the front fork main body S, and the inner buffer chamber Z air in the compression direction of the front fork main body S. Spring force is applied.

The operation of the compression side stroke and the extension side stroke of the front fork main body S in such a configuration is as follows.
[Pressure side stroke]
First, a case where a force in the compression direction acts on the front fork main body S attached between the vehicle body and the axle, and a downward pressing force (in the direction of the holder member 1) acts from the cap member 12 side will be described.
In this case, the downward movement of the cap member 12 on the vehicle body side causes the rod 2 and the piston 3 to move downward (axle direction), and at the same time, the sliding cylinder 11 and the holding cylinder 13 move downward. As a result, the air in the space 31 (buffer chamber B) is compressed by the piston 3, and a reaction force acts on the movement of the piston 3 and the like to apply braking.

The holding cylinder 13 also moves in the same direction as the rod 2, piston 3, etc., and the ring body 15 of the ring piston member 14 descends in the space 8 of the outer buffer chamber M. By lowering the ring body 15, the air in the pressure chamber upper chamber 17 </ b> B in the lower space 17 is compressed while being released to the upper space 16 side through the air flow path 40 of the ring body 15. Further, when the ring body 15 is lowered and all of the air in the pressure chamber upper chamber 17B moves to the upper space 16 and the lower end of the ring body 15 protrudes from the tip of the regulating means 42, the ring body 15 comes into contact with the sliding member 41 and slides. The moving member 41 is pressed downward.
When the lower end of the ring body 15 comes into contact with the upper surface of the sliding member 41 after the ring body 15 has been lowered by a certain distance, the reaction body starts from the pressure chamber 17A, and the ring body 15 continues to descend. Falls while receiving the reaction force of the pressure chamber 17A. Thus, in the outer buffer chamber M, the reaction force until the ring body 15 comes into contact with the sliding member 41 in the compression side stroke, and the new reaction force from the reaction force start position after the contact with the sliding member 41 By receiving, a two-stage reaction force characteristic can be obtained.
Therefore, the length of the regulating means 42 is adjusted by adjusting the dimension of the distance L described above, that is, the protruding length from the lower end of the ring body 15 until the ring body 15 contacts the sliding member 41. The reaction force before pressurizing 17A and the reaction force after pressurizing the pressure chamber 17A are obtained, and the reaction force characteristic can be set in the compression side stroke. Note that the reaction force received from the pressure chamber 17A can be adjusted by the amount of air injected into the pressure chamber 17A.

Further, the air received from the space 31 of the buffer chamber B due to the lowering of the piston 3 is reduced, so that the air in the inner buffer chamber Z expands and acts to promote the lowering of the piston 3.
Therefore, in the compression side stroke in which the front fork main body S in which the piston 3 and the ring body 15 move in the direction of the holder member 1 is compressed, the compression force of the buffer chamber B, the pressure chamber until the ring body 15 comes into contact with the sliding member 41. The cushioning performance that gives the reaction force to the downward movement of the rod 2 and the like due to the compression force of the air in the upper chamber 17B and the expansion force of the air in the inner buffer chamber Z, the compression force of the buffer chamber B, and the ring body 15 Shock absorbing performance that gives a reaction force to the downward movement of the rod 2 and the like, in which the compressive force of the pressure chamber 17A after the air strikes the sliding member 41 and the expansion force of the air in the inner buffer chamber Z are combined. The reaction force characteristics can be adjusted by providing the two-stage buffer characteristics.
Further, since the buffer performance in the buffer chamber B can be shared with the outer buffer chamber M, the force applied to the sealing member on the outer periphery of the piston 3 can be reduced, and the durability can be improved.

[Stretching process]
A front fork body in which a force in the extending direction acts on the front fork main body S and the cap member 12 side moves relative to the holder member 1 upward, that is, the cap member 12 moves relatively away from the holder member 1. A case where S expands will be described.
When the front fork main body S extends from the state in which the pressure chamber 17A is compressed by the sliding member 41, the ring body 15 is pushed upward via the sliding member 41 by the pressure of the pressure chamber 17A. Further, the rod 2 and the piston 3 move upward by the pressure in the buffer chamber B. On the other hand, the air in the inner buffer chamber Z is compressed by the rise of the piston 3, so that a reaction force that prevents the rise of the piston 3 acts.

Then, when the ring body 15 is further inserted into the cap member 12 side from the tip of the restricting means 42 by further rising of the ring body 15, the sliding member 41 comes into contact with the tip of the restricting means 42, and the distance L from the lower end of the rod guide 6 is reached. Ascent is restricted to position.
When the ring body 15 further rises from a state in which the sliding member 41 is restricted from being lifted by the restricting means 42, the pressure in the upper space 16 and the pressure in the lower space 17 are increased in the pressure chamber upper chamber 17B of the outer buffer chamber M. The air in the upper space 16 is vented from the upper space 16 to the lower space 17 through the air flow path 40 of the ring body 15 so that the pressure difference between the upper space 16 and the lower space 17 is reduced. The resistance acts on the rise by the resistance of the flowing air flow path 40.
In addition, the piston 3 that rises together with the ring body 15 rises so that the pressure of the air in the inner buffer chamber Z increases due to this rise, and the difference from the pressure of the air in the buffer chamber B gradually decreases. A braking force is applied to.
As described above, the piston 3 and the ring body 15 are lifted in a well-balanced manner in the extension side stroke, so that the responsiveness in the extension side stroke can also be improved.

  As described above, according to the present invention, by providing the outer buffer chamber M with respect to the buffer chamber B, the pressure from the piston 3 acting on the buffer chamber B is applied to the outer buffer chamber M side by the ring piston member 14. Therefore, it is possible to prevent the load received on the buffer chamber B side, for example, the deterioration of the durability of the sealing member, the seal, and the like provided on the outer peripheral side of the piston 3. In addition, by providing the sliding member 41 whose movement start position is regulated by the regulating means 42 in the outer buffer chamber M so as to be displaceable, it is possible to change the reaction force characteristic in the compression side stroke in two stages. The reaction force characteristics can be adjusted according to the traveling state when the front fork body S is attached to the vehicle.

Further, in the present embodiment, the inside of the buffer chamber B and the inside buffer chamber Z has been described as a simple cavity, but the inside of the buffer chamber B and the inside buffer chamber Z via the oil inlet / outlet valve 1u and the oil inlet / outlet valve 1v described above. By injecting an appropriate amount of hydraulic oil, the compression ratio at the time of the stroke of the pressure chamber upper chamber 17B, buffer chamber B and inner buffer chamber Z of the outer buffer chamber M can be adjusted, and the pressure chamber upper chamber 17B, buffer chamber B and An optimum reaction force characteristic can be obtained by freely changing the mutual influence of the reaction force obtained by the inner buffer chamber Z.
Further, by adjusting the respective air pressures of the pressure chamber 17A of the outer buffer chamber M, the pressure chamber upper chamber 17B of the outer buffer chamber M, the buffer chamber B, and the inner buffer chamber Z, the pressure chamber 17A of the outer buffer chamber M, the outer The air spring force by the pressure chamber upper chamber 17B, the buffer chamber B, and the inner buffer chamber Z of the buffer chamber M can be freely set, and the response characteristics not only in the pressure side stroke but also in the extension side stroke can be improved.

  In the above embodiment, the air channel 40 communicating with the upper space 16 and the lower space 17 formed in the ring body 15 has been described as the concave groove 40a extending from the upper space 16 toward the lower space 17, but this The groove 40a may be formed on the outer periphery of the ring body 15 or may be formed by a through-hole penetrating the ring body 15. In the case where the concave groove 40a as the air flow path 40 is formed on the outer periphery of the ring body 15, the inner periphery of the ring body 15 may be configured to be in sliding contact with the outer periphery of the regulating means 42 described later via a seal member. . Further, when the air flow path 40 is formed by a through hole, the inner periphery and the outer periphery of the ring body 15 are in sliding contact with the outer periphery of the regulating means 42 and the inner periphery of the outermost cylinder 9, which will be described later, via the seal member, respectively. What is necessary is just to comprise. Further, the air flow path 40 is not limited to a concave groove or a through-hole, and an annular gap that provides a predetermined resistance when the ring body 15 moves up and down in the space 8 is provided on the outer periphery of the regulating means 42. Alternatively, it may be configured to be formed with the inner periphery of the outermost cylinder 9.

In the above embodiment, the description has been given on the assumption that one pressure chamber 17A is formed in the outer buffer chamber M. However, the plurality of pressure chambers 17A are slid into the lower space 17 by the above-described sliding member 41, and the above-described sliding is performed. It is also possible to finely change the reaction force characteristics in the pressure side stroke by providing a plurality of members 41, dividing a plurality of pressure chambers, and appropriately adjusting the air pressure between the pressure chambers.
In addition, since this embodiment is a type which obtains damping force with air, the front fork main body S can also be used upside down.

1 holder member, 2 rod, 3 piston, 4 cylinder, 7 outer cylinder,
9 outermost cylinder, 11 sliding cylinder, 12 cap member, 13 holding cylinder,
14 ring piston member, 15 ring body, 16 upper space, 17 lower space,
18 throttle member, 40 air flow path, 41 sliding member, 42 regulating means, B buffer chamber,
M external buffer chamber, S front fork body.

Claims (4)

A holder member provided on the wheel side;
A long inner cylinder that protrudes from the holder member and forms a buffer chamber;
A rod guide provided at the upper end of the inner cylinder;
A piston attached to the rod and housed in the inner cylinder;
An outer cylinder protruding from the holder member so as to form a gap with the outer periphery of the inner cylinder;
An outer cylinder that protrudes from the holder member so as to form an outer buffer chamber consisting of a space at a constant interval with the outer periphery of the outer cylinder, and is longer than the inner cylinder and the outer cylinder;
A sliding cylinder that covers the outer periphery of the outermost cylinder and protrudes toward the holder member from the vehicle body side and slides on the outer periphery of the outermost cylinder;
A cap member on the vehicle body side that seals one end opening of the sliding cylinder and holds one end of the rod;
A holding cylinder protruding from the cap member and positioned between the inner circumference of the outermost cylinder and the outer circumference of the outer cylinder;
A front fork comprising a ring piston member held on the tip side of the holding cylinder,
The ring piston member is formed of a ring body that slides while maintaining airtightness on the outer periphery or inner periphery of the outer buffer chamber, or both, and the outer buffer chamber is partitioned into an upper space and a lower space by the ring body. An air flow path communicating with the upper space and the lower space is provided in the ring body, and a ring-shaped sliding member that is in close contact with an inner periphery and an outer periphery of the lower space, and a pressure is applied by the sliding member. A pressurizing chamber is provided, a regulating means for regulating the distance of the sliding member to the rod guide at a fixed position is provided, and the sliding member can be pressed in the direction of the pressurizing chamber by the ring body. And front fork.   2. The front fork according to claim 1, wherein the air flow path is formed of a concave groove formed on an inner periphery of the ring body and extending in a direction of the upper space and the lower space.   The front fork according to claim 1 or 2, wherein the sliding member includes a seal member fitted in a concave groove provided on an inner and outer periphery of the sliding member.   4. The control means according to claim 1, wherein one end side is attached to the rod guide, and the other end side includes a cylindrical body having a predetermined length extending beyond the ring body in the direction of the sliding member. Front fork.

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