JP2015218897A - Front fork - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve setting of load characteristic change and workability by easily adjusting a load characteristic in an extension side stroke.SOLUTION: A front fork includes working fluid, a cylinder housing a piston, and oil pressure attenuation force generation means. In the front fork, at the upper part of the piston, a first cylindrical body 60 is provided; a second cylindrical body 61 slidable to the first cylindrical part and slidable on a rod 2 is provided; an air chamber P is formed between the first cylindrical body 60 and the second cylindrical body 61; and the air chamber P is compressed in an extension side stroke.

Description

  The present invention relates to a front fork, and more particularly to adjustment of load characteristics in an extension stroke.

  Conventionally, in hydraulic shock absorbers such as front forks and rear cushions of motorcycles, as shown in Patent Document 1, the extension speed when the transition from the compression side stroke to the extension side stroke is reduced by the urging force of the suspension spring is reduced in the extension direction. The urging force is received by a rebound spring.

JP 2012-92944 A

  However, since the load received by the rebound spring is constant regardless of the extension speed of the front fork during travel, it is necessary to replace the rebound spring with the specified characteristics in order to improve the load characteristics. It had the disadvantage of poor setting and work efficiency.

  The present invention has been made in view of these problems, and is capable of easily changing the load characteristics of the front fork in the extension side stroke, and improving the setting and work efficiency of changing the load characteristics. Objective.

  As a configuration of the present invention for solving the above problems, a piston, a rod supporting the piston, the piston is slidably accommodated, and the upper first oil storage chamber and the lower second oil are accommodated by the piston. A cylinder space composed of a longitudinal cylinder partitioned into a storage chamber, a rod guide provided at the top of the cylinder and penetrating the rod to guide the movement of the rod, and formed on the outer periphery of the cylinder space An oil passage chamber, a communication hole that communicates the first oil storage chamber and the oil passage chamber provided in the upper portion of the cylinder, and a holder that seals and fixes the lower portion of the cylinder space and the oil passage chamber A member, a cap member that supports the rod, and a damping force generating means that is connected to both the first lower opening of the second oil storage chamber and the second lower opening of the oil passage chamber, and at the time of compression Above The hydraulic oil pushed out from the first lower opening by the pressing force of ton is passed through the damping force generating means, and after the damping force is applied, the first oil passes from the second lower opening and the oil passage chamber through the communication hole. Circulating through the storage chamber, when the extension is extended, the hydraulic oil in the first oil storage chamber is pushed out of the second lower opening from the oil passage chamber through the communication hole by the pulling force of the piston, and passes through the damping force generating means. A front fork configured to circulate from the first lower opening to the second oil storage chamber after applying a damping force, the first fork having an upward opening provided at the upper part of the piston, and A second cylinder having a downward opening that slides in an expandable manner on the upward opening side of the first cylinder is provided, and air is supplied to an air chamber formed between the first cylinder and the second cylinder. An air valve for injection is provided, and the piston rises when extended In conjunction with this, the first cylinder rises, the second cylinder presses and rises due to the compression force of the air chamber, and the compression force of the air chamber comes into contact with the rod guide against the rod guide. Therefore, the load characteristics can be adjusted simply by adjusting the compression force of the air in the air chamber from the air valve. The desired load characteristic in the extension side stroke can be obtained efficiently.

  Further, as another configuration of the front fork according to the present invention, the upward opening of the first cylinder and the downward opening of the second cylinder are made slidable through the seal member, so that the structure is relatively simple. An air spring comprising an air chamber can be formed.

  Further, as another configuration of the front fork according to the present invention, since the first cylindrical body is integrally provided on the upper end side of the piston, the first cylindrical body can be easily assembled and the overall size and weight can be reduced.

  Further, as another configuration of the front fork according to the present invention, a spring is provided on the upper end side of the rod guide to provide a reaction force against the lowering of the piston rod in the pressure side stroke, so that load characteristics in the pressure side stroke can be simplified. Can be obtained with a simple configuration.

  Further, as another configuration of the front fork according to the present invention, the rod guide is provided at a position separated by a distance L from the second cylindrical body, so that a predetermined performance corresponding to the length of the distance L is obtained during the extension stroke. Load characteristics can be obtained.

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 enlarged view of a front fork. It is sectional drawing of operation | movement description of a front fork.

  FIG. 1 is a cross-sectional view showing an embodiment of a front fork according to the present invention, and FIGS. 2 and 3 are enlarged cross-sectional views of the main part thereof. In each figure, 1 is a holder member attached to the axle side, and this holder member 1 has a fastening bolt 1b for fastening the axle penetrating through the axle attachment hole 1a on the lower side, and a side portion of the holder member 1 On the side, a damping force generation mechanism 70 and a temperature compensation mechanism 130 described later are provided. 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 (not shown) is inserted into the axle mounting hole 1a and tightened with a tightening bolt 1b to narrow the split portion 1y and fix the axle 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.

  Inside 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 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 cylinder 20, and the lower end side of the cylinder 4 is fitted in a sealed state to the lower inner periphery 1 x of the holding cylinder 40 protruding from the holder member 1. An outermost cylinder 9 is erected on the outer periphery of the holding cylinder 40 so as to be concentric with the cylinder 4 on the outer periphery 4 a of the cylinder 4. The lower end inner periphery 41 of the outermost cylinder 9 is screwed to the outer periphery of the holding cylinder 40 via a threaded portion 41m and an O-ring 41n. The cylinder 4 is an inner cylinder provided on the inner side of the outermost cylinder 9 with respect to the outermost cylinder 9.
The outer periphery of the cylinder 4 described above is covered with a thick cylindrical spacer 90, and a gap 5 is formed between the outer periphery of the spacer 90 and the inner periphery 9 b of the outermost cylinder 9. The gap 5 functions as an oil passage chamber R for allowing the hydraulic oil in the upper oil chamber F1 through the communication hole J, which will be described later, to flow to the other end 48 side of the damping force generating mechanism 70, which will be described later. A first lower opening 42 is formed on the bottom side of the lower oil chamber F2 below the piston 3, a groove 5m is formed below the gap 5, and a second lower opening 43 is formed on the bottom side. It is formed. The lower part of the gap 5 communicates with the second lower opening 43 through a minute groove 5m between the cylinder 4 and the holding cylinder 40.
The first lower opening 42 has a ring groove 42a below the lower end of the cylinder 4 on the inner periphery of the holder member 1, and a damping force generation mechanism 70 via a hole 44 extending from a part of the ring groove 42a. The second lower opening 43 is connected from the ring groove 43 a through the hole 47 to the other end 48 side of the damping force generating mechanism 70.

  A stopper 2g is positioned on the outer periphery of the rod 2 at a slightly upper position. The stopper 2g is held by a stopper 2m that is screwed into a stopper holder 2n fixed to the outer periphery of the rod 2 by a 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.

  A cylindrical first cylinder 60 protrudes integrally from the upper outer peripheral side of the piston 3, and a downward opening 61c of the second cylinder 61 having a slightly smaller diameter is formed on the inner periphery of the upward opening 60c of the first cylinder 60. The outer periphery on the side is slidably accommodated via a seal member 62 such as an O-ring 62a, and the first cylindrical body 60 and the second cylindrical body 61 can be expanded and contracted with each other. As shown in FIG. 3, the tip of the upward opening 60 c of the first cylinder 60 is bent at a right angle in the inner direction, that is, the outer peripheral direction of the second cylinder 61, to become a bent portion 60 m. The tip of the downward opening 61c is bent in the outer direction, that is, the outer circumferential direction of the first cylinder 60 to form a bent portion, and both can be locked together, and the second cylinder 61 and the first cylinder 60 is configured not to deviate from the longest state.

In FIG. 1, the top portion 63 of the second cylinder 61 is provided with a through hole 63c that slides on the outer periphery of the rod 2 via a sealing member 63a as a sealing member. An air chamber P is formed by a facing space between the first cylinder 60 and the second cylinder 61, and the air chamber P is moved forward and backward relative to the second cylinder 61. Since the volume is reduced or increased, the air pressure in the air chamber P is increased or decreased and acts as an air spring.
The piston 3 has a small-diameter fixed cylinder 64 protruding from the center of the upper part, and the tip outer periphery of the rod 2 is screwed into the inner periphery of the fixed cylinder 64 in a sealed state. Fixed to the tip. In this case, a hole 65 extending at a right angle to the central axis of the rod 2 is formed in the thick part of the outer periphery of the rod 2 made of a thin cylinder, and the hole 66 communicating with the hole 65 in opposition to the hole 65 is a fixed cylinder. It is formed on the outer peripheral side of the tip of the body 64. Therefore, the inside of the rod 2 communicates with the air chamber P formed by the first cylindrical body 60 and the second cylindrical body 61 through the holes 65 and 66.

As the piston 3 rises during the extension side stroke, the first cylindrical body 60 moves upward. On the other hand, an air valve 19 is provided on the cap member 12 side on the upper end side of the rod 2. Normally, the hollow portion of the rod 2 is sealed with the air valve 19. Accordingly, the plug portion 19N inside the air valve 19 is pressed with an air injection tool (not shown), and air is pressed into the air valve 19 while the air valve 19 is opened. Is supplied to the air chamber P. With such a configuration, the air pressure in the air chamber P can be set to a predetermined height. When the first cylinder 60 rises together with the rod 2, the second cylinder 61 rises together with the rod 2 due to the air pressure in the air chamber P. That is, as shown in the state shown in the figure, the first cylinder 60 and the second cylinder 61 rise while maintaining the longest length.
Since the upper surface 61m of the second cylinder 61 and the lower end portion 6m of the rod guide 6 are separated by a distance L, the second cylinder that has risen in conjunction with the upward movement of the piston 3 during the extension stroke. When the upper surface 61m of the body 61 moves a distance L, as shown in FIG. 4B, the second cylinder 61 is brought into contact with the lower end 6m of the rod guide 6, and the first cylinder 60 is further stopped. When it rises, in this ascending process, the air in the air chamber P is compressed more than the desired pressure, and a further reaction force is generated.
The above is a case where the pressure in the air chamber P is high. When this pressure is relatively low, the second cylinder 61 is somewhat contracted by the pressure received from the hydraulic oil by the rising of the first cylinder 60. Thus, the volume of the air chamber P is reduced. That is, both the first cylindrical body 60 and the second cylindrical body 61 are raised while the total length is reduced. However, in this case as well, when the second cylinder 61 comes into contact with the lower end 6m of the rod guide 6 and stops, the inside of the air chamber P against the ascent of the rod 2 and piston 3 in the extension side stroke as in the case described above. Reaction force is generated by the pressure of.

The lower end inner periphery of the support cylinder 68 having the communication hole J is screwed and fixed to the outer periphery on the tip side of the cylinder 4 in a sealed state. The upper outer periphery of the support cylinder 68 is slidably attached to the inner periphery of the cylinder 4 via a sealing member 69 such as an O-ring. The outer periphery of the rod guide 6 is a threaded portion on the inner periphery of the upper end of the support cylinder 68, and the O-ring. Sealed and fixed with 71 etc. The rod 2 is held by the inner periphery of the rod guide 6 so as to be slidable in the vertical direction via the sealing member 72 and the slide member 73.
A ring-shaped lower receiving portion 74 is positioned at the upper end of the rod guide 6, and a lower end of the cylindrical spacer 75 having a predetermined length is supported by a stepped portion 74 a formed on the inner periphery of the lower receiving portion 74. At the upper end of the spacer 75, a ring-shaped upper receiving portion 76 is supported by a downward stepped portion 76 a, and a spring seat 78 is attached to the upper surface side of the upper receiving portion 76. The lower end of the buffer coil spring 79 positioned so as to wind around the outer periphery of the rod 2 is supported by the spring seat 78, and the upper end of the buffer coil spring 79 is supported by the spring seat 81 described later provided on the cap member 12. Is done. Therefore, the buffer coil spring 79 is seated on the rod guide 6 via the spring seat 78, the upper receiving portion 76, the cylindrical spacer 75, and the lower receiving portion 74.

  On the inner periphery of the buffer coil spring 79, a base portion 80 that contacts the inner periphery of the buffer coil spring 79 and prevents the buffer coil spring 79 from being deformed is positioned. The base 80 is attached so as to surround the outer periphery of the rod 2.

  Reference numeral 11 denotes a large-diameter 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, and on the inner peripheral side of the tip, It has the sealing member 10 which maintains airtight with the outer periphery 9a. 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.

A cylindrical connection tube 12u is attached to the inner periphery of the lower end side of the cylinder 12c of the adjustment bolt 12b. The connecting cylinder 12u includes a flange portion at the center of the outer periphery, and seal members are provided on the upper and lower sides of the flange portion, respectively. The connection cylinder 12u is attached to the adjustment bolt 12b so that the flange portion is attached to the lower end surface of the cylinder body 12c and is in close contact with the inner periphery of the cylinder body 12c by a sealing member on the upper side of the flange section.
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 suspension cylinder 12e is attached to the adjustment bolt 12b so as to sandwich the flange portion of the connection cylinder 12u between the partition piece 12d and the lower end surface 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. At this time, the outer periphery of the rod 2 is in close contact with the seal member below the flange portion of the connecting cylinder 12u, and the inner peripheral space of the adjusting bolt 12b and the inner peripheral space of the rod 2 communicate with each other in a liquid-tight state. A ring-shaped spring seat 81 that moves along the axial direction of the outer periphery of the suspension cylinder 12e is provided on the outer periphery of the suspension cylinder 12e.

Between the above-described ring body 12t and the spring seat 81, a cylindrical spring seat pressing body 12p and a cylindrical pressing body support ring 12q for changing the initial load on the spring 79 are provided. It is done. The spring seat pressing body 12p is provided on the inner peripheral side of the pressing body support ring 12q, and in the circumferential direction by holding means provided between the outer periphery of the spring seat pressing body 12p and the inner periphery of the pressing body support ring 12q. The pressure body support ring 12q is integrated with the pressing body support ring 12q so as to be rotatable with respect to each other but not movable in the axial direction. The integrated spring seat pressing body 12p and the pressing body support ring 12q are such that the open end surface of the pressing body support ring 12q contacts the lower surface of the ring body 12t, and the open end surface of the spring seat pressing body 12p contacts the upper surface of the spring seat 81. Touch.
As a result, by rotating the adjustment bolt 12b, the ring body 12t rotates along the screw on the inner periphery of the cylindrical portion 12f and moves up and down, thereby moving the spring seat pressing body 12p and the pressing body support ring 12q up and down. As a result, the vertical position of the spring seat 81 is displaced and the spring 79 is pressed to adjust the initial spring force.

Next, the configuration of the damping force generation mechanism 70 and the temperature compensation mechanism 130 will be described. FIG. 2 is an enlarged cross-sectional view of a 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 front 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 axis of the front fork main body S, for example.

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 fluid 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 guided from the hole 47 and the gap 5 to the upper oil chamber F1 through the communication hole J. .
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 pushes open the check valve 91a from the through hole 70m, is supplied in the direction of one end 45, and is 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 generating mechanism 70 side to displace part of the hydraulic oil into and out of the oil reservoir chamber 132, and the damping force generating mechanism 70. The volume of the hydraulic oil on the side 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 according to the present invention will be described below. In this case, the hydraulic oil is filled in the buffer chamber B including the upper oil chamber F1, the lower oil chamber F2, the gap 5, the damping force generation mechanism 70, and the oil reservoir chamber 132, and the other spaces are hollow. In this cavity, lubricating oil for lubricating the sliding of the outermost cylinder 9 and the sliding cylinder 11 is injected.

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 oil reservoir chamber 132 are filled with hydraulic oil.
[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, the sliding cylinder 11, the rod 2 and the piston 3 are lowered so that the cap member 12 side is relatively close to the holder member 1 direction. The piston 3 pressurizes the hydraulic oil in the lower oil chamber F2 as the second oil storage reservoir, and supplies it to the one end 45 of the damping force generation mechanism 70 through the ring groove 42a and the hole 44 from the first lower opening 42. And passed from one end 45 toward the other end 48.

In the process of passing through the damping force generating mechanism 70, the hydraulic oil receives a certain resistance (damping force) to the flow, and then the ring groove 43a, the second lower opening 43, the groove 5m, It circulates through the gap 5 and the communication hole J to the upper oil chamber F1 as the first oil storage chamber. As described above, the damping performance due to the damping can be obtained by the operation of the damping force generating mechanism 70 in the compression side stroke of the piston 3 or the like.
Note that the hydraulic oil in the damping force generation mechanism 70 partially flows in the direction of the oil reservoir chamber 132 of the temperature compensation mechanism 130 based on the change in the oil temperature in the operating state of the front fork main body S. The accompanying change in volume of the hydraulic oil due to expansion is absorbed, and the temperature of the hydraulic oil is compensated.

Next, the first cylinder body 60 and the second cylinder body 61 when the compression side stroke is maximum will be described.
When the rod 2 descends following the descending of the cap member 12, the relationship between the rod guide 6 and the second cylinder 61 is a positional relationship separated by a distance L as shown in FIG. Since the air pressure inside the cylindrical body 60 and the second cylindrical body 61 is set high, both of them maintain the longest state.

[Stretching process]
In the extension side stroke in which the front fork main body S extends, the piston 3 rises and the oil in the upper oil chamber F1 receives pressure, and the hydraulic oil in the interior passes through the communication hole J through the gap 5 and the second lower opening 43. The hydraulic oil reaches the other end 48 of the damping force generation mechanism 70, and the hydraulic oil receives the damping force in the damping force generation mechanism 70 and passes through the one end 45, the hole 44, the ring groove 42a, and the first lower opening 42, and the lower oil chamber F2. It circulates to. A predetermined buffer performance is obtained by the damping force. In addition, the hydraulic oil corresponding to the volume expanded due to the temperature rise is supplied to the oil reservoir chamber 132, and temperature compensation for the expansion of the hydraulic oil is performed. Further, when the front fork body S is not operating or when the temperature of the hydraulic oil is lowered, the hydraulic oil is pushed back from the oil reservoir chamber 132 into the cylinder oil chamber F by the pressure of the pressurizing chamber 134 as the volume of the hydraulic oil contracts. It is.

Next, the first cylinder body 60 and the second cylinder body 61 when the compression stroke is maximum will be described.
In addition, air is injected into the hollow portion of the rod 2 from the air valve 19 at the rear end of the rod 2, and this air is injected into the air chamber P through the holes 65 and 66 and is set to a predetermined chamber pressure. And
In this extension side stroke, the piston 3 rises in the cylinder 4 as the rod 2 rises, and the first cylinder 60 integrated with the piston 3 rises, whereby the spring force of the compressed air in the air chamber P is increased. Thus, the second cylinder 61 also moves up (see FIG. 4B).

  Thus, the 1st cylinder 60 and the 2nd cylinder 61 raise, maintaining substantially a series of states. Here, as shown in FIG. 4B, when the second cylinder 61 side moves up by a distance L and the upper surface 61m abuts against the lower end portion 6m of the rod guide, the second cylinder 61 is almost stopped. However, when the rod 2 further rises, the first cylinder 60 rises while compressing the air in the air chamber P, as shown in FIG. As described above, since the air in the air chamber P is compressed, the reaction force at this time restricts the rise of the first cylindrical body 60, and this causes the rod 2 and the piston 3 to extend on the extension side stroke. Since a certain limit is given to the movement of the first stroke, the desired buffer performance is provided almost before the end of the extension stroke.

  Thus, when the extension side stroke proceeds to an appropriate position, a reaction force based on the buffer coil spring 79 and a reaction force based on the air spring of the air chamber P formed by the first cylinder body 60 and the second cylinder body 61 act. Therefore, it is possible to give further cushioning performance over the entire length of the extension side stroke, particularly before the later stage.

The rod 2 is lowered in the contraction side stroke again, whereby the first cylinder 60 and the second cylinder 61 are separated from the rod guide 6 by the second cylinder 61 as shown in FIG. 1 and FIG. It returns to the state separated by L.
In addition, since how much the magnitude of the air spring force by the air chamber P is set depends on how much the air pressure of the air chamber P is set, the reaction force adjustment in the extension side stroke becomes easy. .

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration of the present invention is not limited to this example, and even if there is a design change or the like without departing from the gist of the present invention. It is included in the present invention.

1 Holder member, 2 Rod, 3 Piston, 4 Cylinder, 6 Rod guide,
12 cap member, 19 air valve, 42 first lower opening, 43 second lower opening,
60 first cylinder, 61 second cylinder, 70 damping force generating means,
F Internal space (cylinder space),
F1 upper oil chamber (first oil storage chamber), F2 lower oil chamber (second oil storage chamber), J communication hole,
P air chamber, R oil passage chamber, S front fork body.

Claims (5)

A piston and a rod supporting the piston;
A cylinder space comprising a longitudinal cylinder in which the piston is slidably housed and partitioned into an upper first oil reservoir and a lower second oil reservoir by the piston;
A rod guide provided at an upper portion of the cylinder and guiding the movement of the rod through the rod;
An oil passage chamber formed on the outer periphery of the cylinder space;
A communication hole that communicates the first oil storage chamber and the oil passage chamber provided in the upper part of the cylinder;
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 is passed 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,
At the time of extension, the hydraulic oil in the first oil storage chamber is pushed out from the oil passage chamber through the communication hole by the pulling pressure of the piston from the second lower opening through the damping force generating means, and the damping force is applied. And a front fork configured to circulate from the first lower opening to the second oil storage chamber,
A first cylinder having an upward opening is provided at an upper portion of the piston, and a second cylinder having a downward opening that slides in an expandable manner on the upward opening side of the first cylinder is provided. An air valve for injecting air is provided in an air chamber formed between the first cylinder and the second cylinder, the first cylinder rises in conjunction with the rise of the piston during extension, and the second cylinder A front fork in which the compression force of the air chamber is increased by being pressed and raised by the compression force of the air chamber, and the second cylindrical body comes into contact with the rod guide.   The front fork according to claim 1, wherein the upward opening of the first cylinder and the downward opening of the second cylinder are slidable via a seal member.   The front fork according to claim 1, wherein the first cylindrical body is integrally provided on an upper end side of the piston.   The front fork according to any one of claims 1 to 3, wherein a spring is provided on the upper end side of the rod guide to give a reaction force to the lowering of the piston rod in the pressure side stroke.   The front fork according to any one of claims 1 to 4, wherein the rod guide is provided at a position separated from the second cylindrical body by a distance L.

Images