JP2015197127A - front fork - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a front fork capable of attaining a proper attenuation force irrespective of a running state at a braking time or at a steady running time.SOLUTION: An air passage 40 for communicating an upper space 16 and a lower space 17 defined by a ring body 15 is formed in the ring body 15, and there is formed a ring-shaped slide member 41 which is made to contact closely with the inner circumference and the outer circumference of the lower space 17. There is provided regulation means 49 for regulating the distance to a rod guide 6 of that slide member 41 at a constant position. Moreover, a spring 60 to be interposed between the ring body 15 and the slide member 41 is disposed in a spring chamber 17B over the slide member 41 in the lower space 17.

Description

  The present invention relates to a front fork, and more particularly, to a front fork that improves braking stability and ride comfort.

Conventionally, what is disclosed by patent document 1 is known for the front fork of a two-wheeled vehicle. This is a suspension spring built in a front fork main body in which a vehicle body side tube and a wheel side tube are slidably fitted, and the spring load of the suspension spring can be adjusted by an adjuster member.
However, according to the suspension spring of Patent Document 1, a mechanism for adjusting the spring rate is employed to obtain the desired reaction force characteristics against the stroke change in the compression side stroke and the extension side process. It is difficult to accurately obtain the reaction force characteristics at the road. Especially, the reaction force increases due to the spring load at the back of the stroke and the air spring effect of the compressed air in the front fork, and the shock absorption from the road surface deteriorates. However, it has a drawback that it gives a hard feeling to the ride comfort at the back of the stroke.

JP 2013-177937 A

  The present invention has been made in view of such problems, and is suitable for obtaining a reaction force characteristic corresponding to a change in stroke, and in particular, setting the reaction force characteristic at the back of the stroke to an appropriate state regardless of the running state. An object of the present invention is to provide a front fork that can obtain a sufficient damping force.

  As a configuration of a front fork according to the present invention for solving the above-described problems, a piston, a rod for supporting the piston, the piston is slidably accommodated, and the first oil storage chamber and the second oil are accommodated by the piston. A longitudinal cylinder space partitioned into a storage chamber, an oil passage chamber formed on the outer periphery of the cylinder space, and provided in the upper part of the cylinder, and communicates the first oil storage chamber and the oil passage chamber. A communicating hole, a holder member that seals and fixes a lower portion of the cylinder space and the oil passage chamber, a cap member that supports the rod, a first lower opening of the second oil storage chamber, and the oil passage. Damping force generating means connected on both sides to the second lower opening of the chamber, and the hydraulic oil pushed out from the first lower opening by the pressing force of the piston during compression passes through the damping force generating means to reduce the damping force. Second after granting The oil passage is circulated from the opening, the oil passage chamber to the first oil storage chamber through the communication hole, and the hydraulic oil in the first oil storage chamber is passed through the communication hole by the pressing force of the piston when extended. The hydraulic oil pushed out from the second lower opening through the chamber passes through the damping force generation means, and after applying the damping force, the hydraulic oil is circulated from the first lower opening to the second oil storage chamber, and the outer peripheral side of the oil flow channel chamber A ring-shaped outer buffer chamber is formed on the inner and outer peripheries of the outer buffer chamber, and a ring piston member made of a cylindrical ring body that slides in an airtight manner is accommodated in the outer buffer chamber. In the front fork configured to extend in the direction of the buffer chamber and hold the ring body on the tip side so as to apply a compressive force to the outer buffer chamber by the ring body, the front fork is partitioned by the ring body. Top space and bottom The ring body is provided with an air flow path communicating with the ring body, and a ring-shaped sliding member is provided in close contact with the inner and outer circumferences of the lower space, and the distance of the sliding member to the rod guide is set. Since a restricting means for restricting to a fixed position is provided and a spring interposed between the ring body and the sliding member is provided in the spring chamber above the sliding member in the lower space, a damping force is generated. A sufficient damping force can be obtained by the means. In the compression stroke, the reaction force is received by the compression of the spring, and the reaction force due to the compression force of the spring and the pressure chamber can be transmitted to the ring body. Braking can be provided. Further, in the extension side stroke, air escapes to the upper space side through the air flow path, so that the ring body and the piston are immediately restored, and the responsiveness is improved.

  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 is formed by a concave groove extending to the upper space and the lower space. The desired buffer performance can be obtained by applying the desired pressure to the ring body while restricting the flow of air flowing through the air flow path in accordance with the pressure.

  Further, as another configuration of the front fork according to the present invention, the sliding member has a sealing material fitted in a concave groove provided on the inner and outer circumferences, so that an air spring is provided between the holder member and the sliding member. The pressure chamber which acts as the above can be formed, and a suitable buffering performance can be configured with the spring.

  Further, as another configuration of the front fork according to the present invention, the restriction means includes a cylindrical body having one end attached to the rod guide and the tip side extending beyond the ring body to the sliding member. The initial buffer performance when the chamber is operating can be set.

It is sectional drawing of a front fork. It is an expanded sectional view of a front fork. It is a principal part perspective view of a front fork. It is a principal part expanded sectional view of a front fork. It is sectional drawing of a damping force generation mechanism and a temperature compensation mechanism.

  1 is a cross-sectional view showing an embodiment of a front fork according to the present invention, FIG. 2 is an enlarged cross-sectional view of the main part, FIG. 3 is a perspective view of the main part, and FIG. 4 is an enlarged cross-sectional view of the main part. is there. In each figure, 1 is a holder member attached to the axle side, and this holder member 1 has a tightening bolt 1b for fastening the axle penetrating through the axle attachment hole 1a, and on the side portion side of the holder member 1, A damping force generation mechanism 70 and a temperature compensation mechanism 130 described later are included. In addition, 1i is a brake caliper mounting portion, 1t is a vehicle speed sensor mounting portion, and 1y is a split portion. An axle shaft (not shown) is inserted into the axle mounting hole 1 a and tightened with a bolt 1 b to narrow the split portion 1 y and fix the axle shaft to the holder member 1. A longitudinal front fork main body S that can be expanded and contracted is held between the holder member 1 and the cap member 12 on the vehicle body side. The holder member 1 is provided with a plug portion 53 for injecting hydraulic oil, and the hydraulic oil passes through the plug portion 53 to be described later in an upper oil chamber F1, a lower oil chamber F2, a gap 5, a damping force generation mechanism 70, and temperature compensation. It is injected into the mechanism 130 or the like in advance. In addition, 27 is a fender attachment part for fixing the fender which is formed in a pair on the upper and lower sides so that it may protrude in the side part of the holder member 1, and covers and protects a part of wheel outer periphery.

  In the center of the front fork main body S, a rod 2 made of a thin cylindrical body is positioned along the central axis. The piston 3 is attached to the tip end side of the rod 2, and the rod 2 is inserted through the upper opening of the cylinder 4. The lower end of the rod 2 is fixed to the upper hole 3a of the piston 3 by screwing. Since the slide sealing member 3g is attached to the outer periphery of the lower end of the piston 3, the piston 3 can slide up and down while maintaining a sealed state with the inner periphery 4b of the cylinder 4 as an inner cylinder. The piston 3 divides the internal space (cylinder space) F of the cylinder 4 into an upper oil chamber F1 as a first oil storage chamber and a lower oil chamber F2 as a second oil storage chamber.

  Reference numeral 20 denotes a guide cylinder. The lower end of the guide cylinder 20 is fitted in the hole 1n of the holder member 1 in a sealed state and protrudes upward, and a cylindrical guide 21 is screwed to the outer periphery of the upper end by a screw portion 22. Then, a seal member 24 is attached to the groove 23 in the upper inner periphery of the guide 21, and the guide 21 allows the guide rod 25, which is separate from the rod 2, to advance and retract in the guide cylinder 20. The guide rod 25 is guided by the guide 21 and moves up and down in the guide tube 20 to guide the piston 3 together with the rod 2 linearly along the central axis. Since the hydraulic oil flow passage 30 is formed on the outer periphery of the guide 21, the hydraulic oil in the lower oil chamber F <b> 2 is under pressure from the piston 3 and on the outer periphery of the guide rod 25 and the outer periphery of the guide cylinder 20. There is no change.

The cylinder 4 has a larger diameter than the guide 21, and its lower end side is screwed into the hole 1 x of the holder member 1 in a sealed state, and has a communication hole J on its upper end side. The lower end side of the outer cylinder 7 is fitted in a sealed state on the inner periphery of the holding cylinder 40m protruding from the holder member 1. A gap 5 is formed between the outer periphery 4 a of the cylinder 4 as the inner cylinder and the inner periphery 7 b of the outer cylinder 7. The gap 5 functions as an oil passage chamber R for allowing the hydraulic oil in the upper oil chamber F1 to flow through a damping force generation mechanism 70 described later via the communication hole J. Further, a first lower opening 42 is formed on the bottom side of the lower oil chamber F <b> 2 below the piston 3, and a second lower opening 43 is formed on the bottom side of the gap 5.
The first lower opening 42 is one end of the damping force generating mechanism 70 through a hole 44 extending from a part of a ring groove 42 a formed in a ring shape below the lower end of the cylinder 4 on the inner periphery of the holder member 1. The second lower opening 43 is connected to the other end 48 side of the damping force generating mechanism 70 from the ring groove 43 a through the hole 47.

  The lower outer periphery of the rod guide 6 is screwed and fixed to the upper end inner periphery 7b side of the outer cylinder 7. A slide seal 6a is provided on the inner peripheral side of the rod guide 6, and the outer periphery of the rod 2 is sealed in a sliding state by the slide seal 6a. 6 b is a seal for sealing the outer periphery of the rod guide 6 and the inner periphery 7 b of the outer cylinder 7. A ring-shaped slide sleeve 6 d that supports sliding with the outer periphery of the rod 2 is press-fitted and attached to the lower inner periphery of the rod guide 6. A ring material 6 c is positioned on the lower surface of the rod guide 6. A spring seat 6f is provided at the lower end of the ring material 6c. A slide sleeve 6e is press-fitted and attached to the inner periphery of the spring seat 6f, and the spring seat 6f is configured to be slidable on the outer periphery of the rod 2.

  A stopper 2g is positioned on the outer periphery of the rod 2 at a predetermined position. The stopper 2g is integrated with a stopper 2m that is screwed into a stopper holder 2n that is fixed to the outer periphery of the rod 2 by fixing means (not shown). 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 restricting the downward movement of the piston 3 and the rod 2.

  The outer periphery on the upper side of the piston 3 located slightly on the lower side of the rod guide 6 is tapered, and this portion is a spring seat 3b. A spring 50 is mounted between the spring seat 6f and the spring seat 3b. In this case, the lower part of the spring 50 is attached to the outer periphery of the spring seat 3 b to buffer the collision between the piston 3 and the rod guide 6. Note that the outer periphery of the upper end of the guide rod 25 is fitted into the hole 3d on the lower side of the piston 3 by screwing, and the guide rod 25 is integrated with the rod 2 through the piston 3 in a coaxial manner.

  Further, the base side inner periphery 9b of the outermost cylinder 9 is sealed and fitted so that a space 8 having a constant interval is formed between the outer periphery 7a of the outer cylinder 7 and the outer periphery of the holding cylinder 40m. The space 8 forms an outer buffer chamber M, and is divided into an upper space 16 and a lower space 17 by a ring piston member 14 described later. Reference numeral 1q denotes an O-ring that seals the inner periphery 9b of the outermost cylinder 9 and the outer periphery of the holding cylinder 40m. In this case, the outer cylinder 7 extends slightly above the cylinder 4, but the outermost cylinder 9 is dimensioned to extend upwards considerably longer than the cylinder 4 and the outer cylinder 7.

  11 is a large-diameter cylindrical sliding cylinder extending from the upper end side of the outermost cylinder 9 toward the holder member 1 so as to surround the outer periphery 9a of the outermost cylinder 9, It has the sealing member 10 which keeps airtight with the outer periphery 9a of the outermost cylinder 9. As shown in FIG. Bearings 11 a and 11 b that support each other so as to be slidable with the outermost cylinder 9 are provided on the inner periphery of the sliding cylinder 11 on each of the upper side and the lower side. 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.

The inner periphery of the upper end of the sliding tube 11 is screwed to the outer periphery of the tube portion 12f protruding from the base portion 12n of the cap member 12. An adjustment bolt (support) 12b is attached to the hole 12a of the base 12n in an idle state. Reference numeral 12m denotes an adjustment bolt positioning ring that biases the adjustment bolt 12b upward by the biasing force of the spring 12o to position the adjustment bolt 12b.
A cylindrical cylinder 12s that rotates with the rotation of the adjustment bolt 12b is attached to the outer periphery of the upper part of the cylinder 12c of the adjustment bolt 12b. A groove (not shown) extending along the axial direction of the cylindrical body 12s is formed on the outer periphery of the cylindrical body 12s. Further, an annular ring body 12t having a convex portion formed on the inner peripheral side so as to be movable along the extending direction of the groove is provided on the outer periphery of the cylindrical body 12s. On the outer periphery of the ring body 12t, a thread groove that is screwed with a thread groove formed on the inner periphery of the cylindrical portion 12f is formed.
The upper inner periphery of the suspension cylinder 12e having the partitioning piece 12d is screwed to the threaded portion of the lower outer periphery of the cylinder 12c of the adjustment bolt 12b. The upper end outer periphery of the rod 2 is screwed to the inner periphery of the lower cylinder 12g from the partition piece 12d of the suspension cylinder 12e via the screw portion 12k. The outer periphery of the suspension cylinder 12e is provided with a ring-shaped flange 12i that moves along the axial direction on the periphery of the suspension cylinder 12e. A hat-shaped holding body 12j is provided on the lower surface side of the flange portion 12i, and the inner periphery of the upper end of the holding cylinder 13 is screwed onto the outer periphery of the holding body 12j. The holding cylinder 13 extends in the space 8 direction, and a ring piston member 14 is provided on the tip side. In addition, 13m is a long hole formed in the holding cylinder 13 for weight reduction and air circulation.

Between the ring body 12t and the flange portion 12i, a cylindrical holding cylinder pressing body 12p for enabling the holding cylinder 13 to move in the vertical direction and a cylindrical pressing body support ring 12q are provided. It is done. The holding cylinder pressing body 12p is provided on the inner peripheral side of the pressing body support ring 12q, and the inner periphery of the pressing body support ring 12q and the outer periphery of the pressing body support ring 12q are integrated with the pressing body support ring 12q. The holding means provided therebetween can rotate with respect to each other along the circumferential direction, but are held immovable in the axial direction. In the holding cylinder pressing body 12p and the pressing body support ring 12q that are integrated, the open end surface of the pressing body support ring 12q comes into contact with the lower surface of the ring body 12t, and the open end surface of the holding cylinder pressing body 12p is in contact with the upper surface of the flange portion 12i. Abut.
As a result, by rotating the adjustment bolt 12b, the ring body 12t rotates along the screw on the inner periphery of the cylinder portion 12f and moves in the vertical direction, thereby moving the holding cylinder pressing body 12p and the pressing body support ring 12q up and down. Thus, the vertical position of the holding cylinder 13 is adjusted by displacing the vertical position of the flange 12i and the holding body 12j.

2 and 3, the ring piston member 14 is provided on the lower end side of the holding cylinder 13 so as to be located slightly below the position of the piston 3. 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 is attached by screwing the base portion 15c through a threaded portion 15x on the inner periphery of the distal end side 15w of the holding cylinder 13, and the lower end side of the base portion 15c protrudes from the distal end of the holding cylinder 13 and is the outermost side thereof. An outer seal 15e is provided in sliding contact with the inner periphery 9b of the outer cylinder 9. Thus, as the holding cylinder 13 moves up and down, the ring body 15 slides up and down the inner periphery 9 b of the outermost cylinder 9 while maintaining the same positional relationship as the piston 3.

  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. This air flow path 40 is formed, for example, on the inner periphery of the ring body 15 by forming a concave groove 40 a extending in the direction of the upper space 16 and the lower space 17.

  Further, in the lower space 17 below the ring body 15, a ring-shaped sliding member 41 that is in close contact with the inner periphery and outer periphery of the lower space 17 is provided. The sliding member 41 has a sealing material 41c fitted into concave grooves 41a and 41b provided on the inner and outer circumferences. The sliding member 41 is in contact with the leading end of the restricting means 49, so that the position where the sliding member 41 reaches a certain distance to the leading end of the rod guide 6 is restricted. The restricting means 49 is formed of a cylindrical body having one end attached to the rod guide 6 and the other end extending so as to protrude from the lower end of the ring body 15 by a predetermined length, for example.

  The lower space 17 is partitioned by the sliding member 41 into an upper spring chamber 17B and a lower 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, and the internal pressure is set to a predetermined magnitude in advance. The spring chamber 17B is provided with a spring 60 on the upper side of the sliding member 41.

The spring 60 rotates the adjustment bolt 12b provided on the cap member 12 to move the holding cylinder 13 up and down, and the vertical position of the ring piston member 14 with respect to the ring body 15 is adjusted. For example, when the upper end of the spring 60 is in contact with the lower surface of the ring body 15, the initial spring force of the spring 60 can be set by adjusting the position of the ring piston member 14.
Further, when the ring body 15 moves in the direction of the holder member 1 in the buffering operation of the fork main body S, the lower end of the ring body 15 comes into contact with the upper end of the spring 60 at a fixed position adjusted by the adjustment bolt 12b. The spring 60 is compressed. After the spring 60 is compressed by a predetermined length, the sliding member 41 is pressed toward the holder member 1 through the spring 60. That is, the pressure of the air in the pressure chamber 17 </ b> A is set so as to move downward when a predetermined load is applied to the spring 60.

  With the above configuration, the buffer chamber B is formed by the internal space of the cylinder 4 that accommodates the piston 3, and the outer buffer chamber M having a ring shape is formed by the space 8 between the outer cylinder 7 and the outermost cylinder 9. The

Next, the configuration of the damping force generation mechanism 70 and the temperature compensation mechanism 130 will be described. FIG. 5 is an enlarged cross-sectional view of the main part showing the damping force generation mechanism 70 and the temperature compensation mechanism 130.
The damping force generating mechanism 70 applies a damping force to the hydraulic oil from the one end 45 side in the compression side stroke and causes the hydraulic oil to flow out from the other end 48 side, and applies a damping force to the hydraulic oil from the other end 48 side in the extension side stroke. By flowing out from the one end 45 side, a damping force is applied to the operation of the fork main body S in the compression side and extension side strokes.

  The damping force generation mechanism 70 includes a central cylindrical body 70a, disc-shaped partition plates 70b and 70c fixed to the outer periphery of both sides of the central cylindrical body 70a, and a through hole 70d formed in the partition plate 70b on the one end 45 side. A pressure-side damping valve 70e attached to the other end 48 side of the partition plate 70b so as to close and a through hole 70g formed in the partition plate 70c on the other end 48 side are attached to one end 45 side of the partition plate 70c. The expansion side damping valve 70h, the intermediate chamber 70i formed by the space between the compression side damping valve 70e and the extension side damping valve 70h, and the needle valve 70j positioned at the center of the central cylinder 70a are provided.

  A disc-shaped ring body 80a is provided between the compression side damping valve 70e and the extension side damping valve 70h. In the ring body 80a, a plurality of through holes 80b penetrating in the radial direction from the inner periphery to the outer periphery are radially formed in the central portion in the thickness direction. In addition, a through-hole 80c that penetrates the central cylinder 70a in the radial direction is provided in the central cylinder 70a so as to correspond to the through-hole 80b. The central hole 80d of the central cylinder 70a has a small diameter hole 80e on one end 45 side, a large diameter hole 80f on the opposite side, and an angle forming a gap 90a with the taper 80g at the tip of the needle valve 70j on the other end 48 side of the small diameter hole 80e. A portion 90b is formed. Further, a taper member 90f is provided on the base side of the needle valve 70j, and a corner portion 90d that forms a gap 90c is formed by the taper of the taper member 90f.

  The needle valve 70j is finely adjusted by the adjusting mechanism 90e so as to freely advance and retract. 91a is a check valve for closing the through hole 70m from the one end 45 side, and 91b is a check valve for closing the through hole 70n from the other end 48 side. Each of the compression side damping valve 70e, the extension side damping valve 70h, and the check valves 91a and 91b is configured by laminating a plurality of elastic thin plates. Such a damping force generation mechanism 70 is provided on the side of the holder member 1 so as to be inclined with respect to the front fork main body S.

According to the above configuration, in the pressure side stroke, the hydraulic oil L1 from the one end 45 side flows into the through hole 70d, pushes and opens the pressure side damping valve 70e, and is supplied to the intermediate chamber 70i. From the through hole 80c of the central hole 80d through the gap 90a and supplied to the intermediate chamber 70i through the through hole 80b of the ring body 80a. The hydraulic oil in the intermediate chamber 70i pushes open the check valve 91b through the through hole 70n, is supplied in the direction of the other end 48, and is led from the hole 47 and the gap 5 to the upper oil chamber F1 through the communication hole J. Circulate.
Further, during the extension side stroke, the hydraulic oil L2 from the other end 48 side flows in through the through hole 70g, pushes the extension side damping valve 70h open, is supplied to the intermediate chamber 70i, and communicates with the large diameter hole 80f. It is supplied from the hole 93 to the intermediate chamber 70i through the through hole 80c of the central hole 80d. The hydraulic oil in the intermediate chamber 70i is supplied in the direction of the one end 45 by pushing the check valve 91a through the through hole 70m and is circulated by being guided to the lower oil chamber F2.

  In the operation of generating the damping force by the damping force generating mechanism 70 described above, the volume change of the hydraulic oil due to the temperature change of the hydraulic oil is guided to the temperature compensation mechanism 130 via the passage 115 opened to the intermediate chamber 70i. Compensation is made. The temperature compensation mechanism 130 includes an oil reservoir chamber 132 in which a passage 115 opens and a pressurizing chamber 134 defined by a free piston 133 whose position is freely displaceable, and is enclosed in the pressurizing chamber 134. Displacement of the free piston 133 causes the balance between the gas pressure and the hydraulic oil pressure on the damping force generation mechanism 70 side to displace the hydraulic oil into and out of the oil reservoir 132, thereby operating the damping force generation mechanism 70 side. The oil volume is maintained constant, and a stable damping force that does not depend on the outside air temperature or the temperature rise of the hydraulic oil due to the operation of the front fork main body S can be obtained.

  The operation of the front fork main body S in the above configuration will be described below. In this case, the upper oil chamber F1, the lower oil chamber F2, the gap 5, the damping force generation mechanism 70, and the buffer chamber B including the oil reservoir chamber 132 are filled with hydraulic oil, and the upper space 16 and the lower portion constituting the outer buffer chamber M are filled. It is assumed that only the space 17 is hollow. Further, it is assumed that the air pressure in the pressure chamber 17A of the lower space 17 is set to a predetermined pressure level by the air valve 1A.

[Pressure side stroke]
In the compression side stroke in which the front fork main body S attached to the vehicle body side and the axle side contracts, a buffering operation by hydraulic pressure is performed by the damping force control of the hydraulic oil of the damping force generation mechanism 70 as described above. On the other hand, when the cap member 12 relatively moves in the direction of the holder member 1, the holding cylinder 13 is lowered, the ring body 15 is lowered, and the spring 60 in the spring chamber 17B is compressed. Further, the ring body 15 is lowered to a certain distance while compressing the spring 60. When the ring body 15 continues to descend and a load is applied from the ring body 15 to the spring 60 to start air compression in the pressure chamber 17A, the spring 60 further presses against the sliding member 41 while being compressed. Start compressing the air in chamber 17A. In this case, when the ring body 15 is lowered, the compressed air from the upper part on the cap member 12 side is also sent to the spring chamber 17B via the air flow path 40, so that the sliding member is also affected by the air pressure in the spring chamber 17B. It contributes to pressing 41 possible.

  That is, when the ring body 15 descends while sliding on the inner periphery 9b of the outermost cylinder 9, first, the spring 60 is compressed, and further, a load for compressing the air in the pressure chamber 17A is applied to the spring 60. The spring 60 compresses the pressure chamber 17A by pressing the sliding member 41 downward while being further compressed. As described above, in the present embodiment, a two-stage reaction force is applied, which is a reaction force due to the compression of the spring 60 and a combined reaction force combining the reaction force due to the compression of the spring 60 and the reaction force due to the compression of the pressure chamber 17A. Therefore, based on the adjustment of the spring force of the spring 60 and the adjustment of the air spring force of the pressure chamber 17A, a desired reaction force characteristic at each stroke length can be obtained. Moreover, the sliding member 41 is stopped at the tip of the restricting means 49, and is pressed from the position of the tip to compress the pressure chamber 17A. Therefore, the length of the restricting means 49 is set in advance. Thus, the compression ratio of the pressure chamber 17A can be changed, the spring characteristic at the back of the stroke on which the sliding member 41 slides can be changed, and the riding comfort that normally occurs at the back of the stroke can be improved.

[Stretching process]
Also in this case, the buffering operation by hydraulic pressure is performed by the damping force control of the damping force generation mechanism 70. On the other hand, as the rod 2 rises, the sliding member 41 rises while receiving the reaction force contained in the spring 60 during the compression stroke and the reaction force contained in the pressure chamber 17A, and comes into contact with the tip of the regulating means 49. Stop. Thereafter, the ring body 15 is subjected to a reaction force by the spring 60 and a resistance force acting when air in the upper space 16 opposite to the reaction force flows to the spring chamber 17B side through the air flow path 40. Since the extension side stroke is performed, the damping force can be applied while ensuring the responsiveness of the extension operation of the front fork main body S.

  As described above, the front fork main body S according to the present invention includes the spring 60 that functions as a buffer against the outer buffer chamber M formed as an air spring chamber, and the ring piston member 14 that presses the spring 60 from one end side. A pressure member 17A to which a predetermined air pressure is applied so as to support the spring 60 pressed from the ring piston member 14 from the other end side, and a sliding member 41 whose movement range is restricted by the restriction means 49; And the internal pressure of the pressure chamber 17A is applied so that the sliding member 41 moves when the load acting on the spring 60 becomes equal to or greater than the set load. Then, when a predetermined shock-absorbing characteristic is obtained by the spring 60 and a load exceeding the set load is applied to the spring 60, the spring is applied. 60 and for the combined spring characteristics due to air spring pressure chamber 17A is obtained, it is possible to improve the shock absorption performance of the stroke back. That is, when absorbing an impact from a small road surface, the shock is absorbed only by the spring 60, and when passing through a gap that requires a large stroke amount, the impact is absorbed by the combined spring characteristics of the spring 60 and the air spring of the pressure chamber 17A. Therefore, it is possible to improve ride comfort and shock absorption performance at the back of the stroke.

  In addition, according to the configuration of the present invention, the volume of the outer buffer chamber M other than the pressure chamber 17A can be increased, and therefore the pressure fluctuation of the air in the outer buffer chamber M other than the pressure chamber 17A is changed during the operation of the front fork main body S. Since the size can be reduced, the response of the buffering operation can be improved. In particular, since the reaction force due to the air spring effect of the air compressed in the outer buffer chamber M other than the pressure chamber 17A at the back of the stroke in the compression side stroke does not increase, the shock absorption from the road surface is improved, and the Ride comfort 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. When 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 in sliding contact with the outer periphery of the restricting means 49 via the seal member. 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 a restricting means 49 described later and the inner periphery 9b of the outermost cylinder 9 via a 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 49. Alternatively, the outermost cylinder 9 may be formed with the inner periphery 9b.

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 14 ring body, 16 upper space, 17 lower space,
17A pressure chamber, 17B spring chamber, 40 air flow path, 41 sliding member,
49 regulating means, 60 spring, 70 damping force generation mechanism, 130 temperature compensation mechanism,
F cylinder space, F1 first oil storage chamber, F2 second oil storage chamber, J communication hole,
M outer buffer chamber, R oil passage chamber, S front fork body.

Claims (4)

A piston and a rod supporting the piston;
A longitudinal cylinder space in which the piston is slidably housed and partitioned by the piston into a first oil storage chamber and a second oil storage chamber;
An oil passage chamber formed on the outer periphery of the cylinder space;
A communication hole provided in the upper part of the cylinder and communicating the first oil storage chamber and the oil passage chamber;
A holder member for sealing and fixing a lower portion of the cylinder space and the oil flow path chamber;
A cap member for supporting the rod;
A damping force generating means connected on both sides to the first lower opening of the second oil storage chamber and the second lower opening of the oil passage chamber;
The hydraulic oil pushed out from the first lower opening by the pressing force of the piston at the time of compression passes through the damping force generating means, and after giving the damping force, from the second lower opening and the oil passage chamber through the communication hole. Circulating to the first oil reservoir,
When the hydraulic oil in the first oil storage chamber is pushed out from the oil flow passage chamber through the communication hole through the second lower opening by the pressing force of the piston at the time of extension, the damping force is generated via the damping force generating means. And then circulate from the first lower opening to the second oil reservoir.
A ring-shaped outer buffer chamber is formed on the outer peripheral side of the oil channel chamber, and a ring piston member made of a cylindrical ring body that slides while maintaining airtightness on the inner and outer periphery of the outer buffer chamber is housed, and A front fork configured to extend in the direction of the outer buffer chamber from the cap member side and to hold the ring body on the tip side so as to apply a compressive force to the outer buffer chamber by the ring body. ,
The ring body is provided with an air flow path that communicates the upper space and the lower space partitioned by the ring body, and a ring-shaped sliding member that is in close contact with the inner and outer circumferences of the lower space is provided. Providing a regulating means for regulating the distance of the sliding member to the rod guide at a certain position,
The front fork further comprises a spring interposed between the ring body and the sliding member in a spring chamber above the sliding member in the lower space.   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 to the upper space and the lower space.   The front fork according to claim 1, wherein the sliding member has a sealing material fitted in a concave groove provided on an inner and outer periphery.   The front fork according to any one of claims 1 to 3, wherein the regulating means includes a cylindrical body having one end attached to the rod guide and a distal end extending beyond the ring body to the sliding member.