JP2024053137A - Front fork - Google Patents

Abstract

[Problem] To provide a front fork with reduced manufacturing costs. [Solution] A bracket 16 capable of holding an axle side end 11a of a telescopic body 11 is provided with a pressurizing device 60 capable of pressurizing oil inside a control valve 50. A pressurizing member 61 and a pressurizing source 62 of the pressurizing device 60 are housed in a housing hole 64 formed integrally with the bracket 16. A center line Cp of the pressurizing device 60 is at a different position from an axis C of the telescopic body 11. [Selected Figure] Fig. 3

Description

The present invention relates to a front fork equipped with a damping force generating device and a pressure applying device.

Saddle-type vehicles, such as motorcycles and three-wheeled vehicles, are equipped with hydraulic shock absorbers that connect the axles to the vehicle body and absorb vibrations from the road surface. Prior art related to such hydraulic shock absorbers is disclosed in Patent Document 1.

The hydraulic shock absorber disclosed in Patent Document 1 is a front fork that is provided on a motorcycle. This front fork is equipped with a telescopic body that can expand and contract as a whole, including an outer tube and an inner tube that is partially arranged within the outer tube so that it can advance and retreat.

Inside the telescopic body are a cylinder, a piston that divides the inside of the cylinder into an upper first oil chamber and a lower second oil chamber, and a rod fixed to the piston.

When an impact is applied to the telescopic body from the wheel, the piston moves and oil (hydraulic oil) flows between the first and second oil chambers through a communication hole formed in the piston, generating a damping force due to the resistance of the oil flow path, and the front fork absorbs the impact.

JP 2017-180692 A

The front fork further includes a damping force generating device that is connected to the second oil chamber on the lower side and is capable of generating a damping force, and a pressurizing device that is capable of pressurizing the oil in the damping force generating device. By including the damping force generating device and the pressurizing device, the responsiveness of the damping force can be improved. However, the manufacturing costs of a front fork that includes a damping force generating device and a pressurizing device are high.

The present invention aims to provide a front fork that can reduce manufacturing costs.

After extensive research, the inventor has discovered that it is possible to provide a front fork that can reduce manufacturing costs, comprising a bracket that holds the axle-side end of the telescopic body, a control valve that communicates with the second oil chamber of the cylinder, and a pressurizing device that can pressurize the oil inside the control valve, the pressurizing device comprising a pressurizing member that can pressurize the oil by contacting the oil, and a pressurizing source that applies force to the pressurizing member so that the pressurizing member can apply pressure to the oil, the pressurizing member and the pressurizing source being stored in a storage hole that is integrally formed with the bracket, and the center line of the pressurizing device being in a different position relative to the axis of the telescopic body. The present invention was completed based on these findings.

According to the present disclosure, there is provided a front fork having an outer tube, an inner tube partially disposed within the outer tube, a cylinder disposed inside the outer tube and the inner tube, a piston dividing the interior of the cylinder into an upper first oil chamber and a lower second oil chamber, and a rod fixed to the piston, in which the outer tube and the inner tube move forward and backward relative to each other, and the outer tube and the inner tube expand and contract as a whole, thereby moving the piston in the cylinder to generate a damping force, a bracket holding the axle side end of the telescopic body, a control valve communicating with the second oil chamber, and a pressurizing device capable of pressurizing the oil inside the control valve, the pressurizing device comprising a pressurizing member capable of pressurizing the oil by contacting the oil, and a pressurizing source that applies a force to the pressurizing member so that the pressurizing member can apply pressure to the oil, the pressurizing member and the pressurizing source being housed in a housing hole formed integrally with the bracket, and the center line of the pressurizing device being at a different position relative to the axis line of the telescopic body.

This disclosure makes it possible to provide a front fork that is easily attached to the vehicle body.

1 is a side view of a motorcycle equipped with a front fork according to an embodiment. 2 is a cross-sectional view of the vicinity of the front wheel axle of the motorcycle shown in FIG. 1. 1 illustrates the location of the control valve and the pressure device relative to the bracket holding the telescopic body.

The embodiment of the present invention will be described below with reference to the attached drawings. In the drawings, Up indicates the top and Dn indicates the bottom.

Example 1
Please refer to Fig. 1. The shock absorber 10 is, for example, a front fork used in an off-road type two-wheeled vehicle 100 (saddle-ride type vehicle 100). Hereinafter, the shock absorber 10 will be referred to as a front fork 10 for explanation.

The motorcycle 100 has a body 111, an engine 112 as a power source supported at the center of the body 111, left and right front forks 10 (only the right front fork 10 is shown in FIG. 1) that are provided on the left and right sides of the front of the body 111 and absorb shocks from unevenness in the road surface, a front wheel 114 that is sandwiched between the lower ends of the front forks 10 and supported rotatably, a handle pipe 115 that is provided on the upper part of the front fork 113 and steers the front wheel 114, a seat 116 that is provided above the engine 112 and on which a rider sits, a swing arm 117 that extends rearward from the rear of the body 111 and can swing relative to the body 111, a rear wheel 118 that is supported rotatably by the rear end of the swing arm 117, and left and right rear suspensions 113 that are stretched from the rear of the body 111 to the swing arm 117 (only the right rear suspension 113 is shown in FIG. 1).

The left and right front forks 10 have the same configuration. Below, the right front fork 10 will be explained, and an explanation of the left front fork will be omitted. Note that the left and right front forks 10 can also have different configurations depending on the purpose.

[Stretchable body, outer tube, inner tube]
Please refer to Fig. 2. The front fork 10 is equipped with a telescopic body 11 that can expand and contract in the vertical direction. The telescopic body 11 is equipped with a cylindrical outer tube 12 that extends in the vertical direction, and a cylindrical inner tube 13 that is partially disposed within the outer tube 12. The total length (dimension in the vertical direction) of the telescopic body 11 changes as the outer tube 12 and the inner tube 13 advance and retreat relative to each other in the vertical direction.

[Cylinder, piston, rod]
The telescopic body 11 comprises a cylindrical cylinder 21 provided inside the inner tube 13, a piston 24 dividing the inside of the cylinder 21 into a first oil chamber 22 at the top (vehicle body side) and a second oil chamber 23 at the bottom (axle side), and a rod 25 extending upward from the piston 24.

Between the inner circumferential surface of the inner tube 13 and the outer circumferential surface of the cylinder 21, there is arranged a compression coil spring 14 that applies forces to the inner tube 13 and the outer tube 12 to move them in opposite directions, and a cylindrical support member 15 that supports the compression coil spring 14.

The lower end of the cylinder 21 is blocked by a first blocking member 26. The first blocking member 26 has an extension 27 that extends downward. The lower end of the inner tube 13 is blocked by a second blocking member 28. The extension 27 of the first blocking member 26 passes through the second blocking member 28 and is supported by the second blocking member 28.

[Stretching function]
When the telescopic body 11 expands and contracts due to the impact from the wheels and the force of the compression coil spring 14, the piston 24 in the cylinder 21 moves. Oil (hydraulic oil) flows between the first oil chamber 22 and the second oil chamber 23 through a communication hole formed in the piston 24, generating a damping force due to the flow resistance of the oil.

As long as the damping force can be generated by the expansion and contraction of the expansion body 11, the internal configuration of the expansion body 11 is not limited to that of the embodiment. Furthermore, in the embodiment, an inverted front fork in which the inner tube 13 is located below the outer tube 12 is shown, but the configuration of the present invention may be adopted in an upright front fork in which the outer tube 12 is located below the inner tube 13.

[bracket]
The axle side end 11a of the telescopic body 11 is held by a bracket 16. The bracket 16 has a first retaining hole 31 that holds the axle side end 11a and a support hole 32 that can support the axle (the bracket 16 can also be said to be a member that connects the telescopic body 11 and the axle). An internal thread is formed on the end face of the extension part 27 that protrudes from the second blocking member 28. The axle side end 11a is fixed to the bracket 16 by fastening the internal thread to a bolt 29.

The caliper support portion 40 is equipped with a control valve 50 whose interior is connected to the second oil chamber 23, and a pressure device 60 capable of pressurizing the oil in the control valve 50.

[Control valve]
The control valve 50 may have a known configuration, for example, a damping force generating valve that generates a damping force by moving oil between the oil chambers in the control valve 50 as the telescopic body 11 expands and contracts, a damping force adjustment valve, a flow control valve, a switching valve, or the like, as long as the inside is in communication with the second oil chamber. The control valve 50 is held in a second holding hole 41 formed in the bracket 16. An opening 41a of the second holding hole 41 faces the same direction as support surfaces 43, 46 described below.

[Pressure device]
The pressurizing device 60 includes a free piston 61 (pressurizing member) that contacts the oil and applies pressure to the oil, and a gas 62 (pressurizing source) that applies force to the pressurizing member so that the free piston 61 applies pressure to the oil.

The free piston 61 and the gas 62 are stored in a generally cylindrical storage hole 64 that is formed integrally with the bracket 16. The inner peripheral surface 65 of the storage hole 64 is a surface on which the outer peripheral surface of the free piston 61 can slide. The space defined by the inner peripheral surface 65 of the storage hole 64 is a space that can be filled with the gas 62.

The opening 64a of the storage hole 64 faces the same direction as the support surfaces 43 and 46 described below. The opening 64a of the storage hole 64 is closed by a cap 63. The cap 63 has an injection valve 66 that can inject gas 62 into the inside of the storage hole 64.

The pressure device 60 may be a combination of a bladder (pressure member) and gas 62, or a combination of a free piston 61 and a compression coil spring (pressure source), and the configuration is not limited to the embodiment.

[Support surface]
The bracket 16 is provided with a caliper support portion 40 capable of supporting a brake caliper 70. The caliper support portion 40 is composed of an upper first protruding portion 42 and a lower second protruding portion 45, which protrude from the edge of the bracket 16 toward the outside in the radial direction of the axle. The first protruding portion 42 and the second protruding portion 45 are spaced apart from each other by a predetermined distance so as to be able to support a first end portion 71 and a second end portion 72 located at both ends of the brake caliper 70.

The first end 71 is fixed to the first protrusion 42 by a bolt 73 (fastening member). In detail, the first protrusion 42 has a first support surface 43 that can contact the first end 71 and support the brake caliper 70. The first support surface 43 has a first fastening hole 44 that is fastened to the bolt 73.

The second end 72 is fixed to the second protrusion 45 by a bolt 73 (fastening member). In detail, the second protrusion 45 has a second support surface 46 that can contact the brake caliper 70 and support the brake caliper 70. The second support surface 46 has a second fastening hole 47 that is fastened to the bolt 73.

[Position of control valve and pressurizing device relative to the boundary surface]
3, a plane including the first support surface 43 and the second support surface 46 is referred to as boundary surface B. With boundary surface B as a boundary, the side on which the caliper support portion 40 is located is referred to as the support portion side, and the side on which the brake caliper 70 is located is referred to as the caliper side. Both the control valve 50 and the pressurizing device 60 are located entirely on the support portion side.

[Location of control valve and pressure device relative to centerline of fastening hole]
The control valve 50 and the pressurizing device 60 are located between the first center line C1 of the first fastening hole 44 and the second center line C2 of the second fastening hole 47.

[Location of control valve and pressure device]
The pressurizing device 60 and the control valve 50 are arranged in parallel. For example, as shown in Fig. 3, when viewed from a direction along the axis line AX of the axle, the pressurizing device 60 and the control valve 50 are arranged in a direction D perpendicular to the pressurizing direction of the pressurizing device 60. The control valve 50 is located above the pressurizing device 60. Note that the center line Cp of the pressurizing device 60 (a line extending in the pressurizing direction) and the center line Cd of the control valve 50 (a center line of a cylindrical case) are not necessarily located on the same plane.

Furthermore, the center line Cp of the pressurizing device 60 and the center line Cd of the control valve 50 are parallel to the first center line C1 and the second center line C2, but the control valve 50 and the pressurizing device 60 may be arranged so as to be oblique to the first center line C1 and the second center line C2.

A part of the control valve 50 is located below the telescopic body 11. That is, the control valve 50 extends into the space below the telescopic body 11 inside the bracket 16.

[Effects of the embodiment]
First, the bracket 16 has a storage hole 64. The outer peripheral surface of the free piston 61 is slidable against the inner peripheral surface 65 of the storage hole 64. Gas 62 is filled in the space defined by the inner peripheral surface 65 of the storage hole 64. The pressurizing device of the prior art includes a pipe that stores the free piston and can be filled with gas. The pressurizing device 60 of the embodiment does not require such a pipe. The number of parts constituting the pressurizing device 60 can be reduced, and the manufacturing costs of the front fork can be suppressed.

The brackets of the prior art require an insertion hole into which the lower end of the pipe is inserted. Even if the storage hole 64 is integrally formed when manufacturing the bracket 16 by casting or forging, the manufacturing cost of the bracket 16 does not increase compared to the brackets of the prior art.

In addition, the center line Cd of the pressure device 60 is at a different position relative to the axis C of the telescopic body 11. In other words, the pressure device 60 is not built into the telescopic body 11. Generally, there are front forks in which the center line of the pressure device overlaps with the axis of the telescopic body and the pressure device is built into the end of the telescopic body. Compared to such front forks, in the embodiment, the axial dimension of the telescopic body 11 can be shortened, so the front fork 10 can be made smaller.

Secondly, the control valve 50 is provided on the bracket 16. Compared to a telescopic body that has a built-in control valve, the dimensions of the telescopic body 11 can be made shorter.

Thirdly, the control valve 50 and the pressurizing device 60 are both located entirely on the caliper support side, with boundary surface B as the boundary. In other words, the control valve 50 and the pressurizing device 60 do not protrude toward the caliper side. The control valve 50 and the pressurizing device 60 do not interfere with the installation of the brake caliper 70.

The positions of the control valve 50 and the pressure device 60 are not limited to the example shown in FIG. 3, as long as they are both positioned entirely on the support side. The orientation of the control valve 50 and the pressure device 60 (the direction in which the center lines Cp and Cd extend) can be changed as appropriate, and the control valve 50 and the pressure device 60 can also be arranged in the direction along the axis AX of the shaft member (the front-to-back direction in FIG. 3).

Fourth, the pressurizing device 60 and the control valve 50 are arranged in parallel. If the control valve 50 were arranged in series along the pressurizing direction of the pressurizing device 60, the pressurizing device 60 and the control valve 50 would become longer overall. On the other hand, if the pressurizing device 60 and the control valve 50 are arranged in parallel, they are less likely to overlap with other devices or parts.

In detail, the control valve 50 and the pressurizing device 60 are located between the center line C1 of the first fastening hole 44 and the center line C2 of the second fastening hole 47. The first protrusion 42 and the second protrusion 45 are spaced apart so that they can support both ends 71, 72 of the brake caliper 70. By arranging the control valve 50 and the pressurizing device 60 in the space created by this gap, the space can be used effectively.

As long as the present invention has the functions and effects, it is not limited to the embodiment. In the embodiment, the bracket 16 is equipped with a caliper support portion 40, but the configuration of the present invention can also be used in a bracket that does not have a caliper support portion 40 for a model with a one-sided brake.

The front fork of the present invention is suitable for use as a hydraulic shock absorber for a motorcycle.

10...Front fork 11...Telescopic body 11a...Axle side end portion 12...Outer tube 13...Inner tube 21...Cylinder 22...First oil chamber 23...Second oil chamber 24...Piston 25...Rod 40...Caliper support portion 43...First support surface 44...First fastening hole 46...Second support surface 47...Second fastening hole 50...Control valve 60...Pressurizing device 61...Free piston (pressurizing member)
62...Gas (pressurization source)
64...housing hole 70...brake caliper 73...bolt (fastening member)
AX...axis line of the axle B...boundary surface C...axis line of the telescopic body C1...center line of the first fastening hole C2...center line of the second fastening hole Cp...center line of the pressure device D...direction perpendicular to the pressure direction

Claims (5)

an expandable body having an outer tube, an inner tube partially disposed within the outer tube, a cylinder disposed inside the outer tube and the inner tube, a piston dividing the interior of the cylinder into an upper first oil chamber and a lower second oil chamber, and a rod fixed to the piston, wherein the outer tube and the inner tube advance and retreat relative to each other, and the outer tube and the inner tube expand and contract as a whole, thereby moving the piston in the cylinder and generating a damping force;
A bracket that holds the axle side end of the telescopic body;
a control valve communicating with the second oil chamber;
a pressure device capable of pressurizing the oil inside the control valve,
the pressurizing device includes a pressurizing member capable of contacting the oil to pressurize the oil, and a pressurization source that applies a force to the pressurizing member so that the pressurizing member can apply pressure to the oil,
the pressure member and the pressure source are housed in a housing hole formed integrally with the bracket,
A front fork, wherein a center line of the pressure applying device is at a different position relative to an axis line of the telescopic body. The front fork of claim 1, wherein the control valve is provided on the bracket. The bracket includes a caliper support portion capable of supporting a brake caliper,
the caliper support portion has a support surface capable of contacting the brake caliper and supporting the brake caliper,
3. The front fork according to claim 2, wherein a plane including the support surface is defined as a boundary surface, and the control valve and the pressurizing device are located on the caliper support portion side of the boundary surface. The front fork according to claim 3, wherein the control valve and the pressure device are arranged in parallel. an expandable body having an outer tube, an inner tube partially disposed within the outer tube, a cylinder disposed inside the outer tube and the inner tube, a piston dividing the interior of the cylinder into an upper first oil chamber and a lower second oil chamber, and a rod fixed to the piston, wherein the outer tube and the inner tube advance and retreat relative to each other, and the outer tube and the inner tube expand and contract as a whole, thereby moving the piston in the cylinder and generating a damping force;
A bracket that holds the axle side end of the telescopic body;
a control valve communicating with the second oil chamber;
a pressure device capable of pressurizing the oil inside the control valve,
The pressurizing device includes a pressurizing member capable of contacting the oil to pressurize the oil, and a pressurization source that applies a force to the pressurizing member so that the pressurizing member can apply pressure to the oil,
the pressure member and the pressure source are housed in a housing hole formed integrally with the bracket,
The center line of the pressure device is at a different position relative to the axis of the stretchable body,
The control valve is provided on the bracket,
The bracket includes a caliper support portion capable of supporting a brake caliper,
the caliper support portion has a first support surface and a second support surface capable of contacting the brake caliper and supporting the brake caliper,
a plane including the first support surface and the second support surface is defined as a boundary surface, and the control valve and the pressurizing device are located closer to the caliper support portion than the boundary surface,
The control valve and the pressurizing device are arranged in parallel,
The first support surface has a first fastening hole capable of being fastened with a fastening member capable of fixing the brake caliper,
The second support surface has a second fastening hole capable of being fastened with a fastening member capable of fixing the brake caliper,
an inverted front fork, wherein the control valve and the pressurizing device are located between a first center line of the first fastening hole and a second center line of the second fastening hole;

Images