Front fork
The front fork design integrates a bracket with a control valve and pressurizing device, offset from the axis, to reduce manufacturing costs and complexity, enhancing responsiveness and ease of attachment, while minimizing interference with other components.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- ASTEMO LTD
- Filing Date
- 2022-10-03
- Publication Date
- 2026-05-19
AI Technical Summary
Front forks with damping force generating devices and pressurizing devices have higher manufacturing costs due to complex structures and additional components.
The front fork design incorporates a bracket with a control valve and a pressurizing device, where the pressurizing member and source are housed in a storage hole formed integrally with the bracket, and the centerline of the pressurizing device is offset from the axis of the extendable body, reducing the number of parts and overall size.
This design reduces manufacturing costs and allows for easier attachment to the vehicle body while maintaining responsiveness, without interfering with other components like the brake caliper.
Smart Images
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Abstract
Description
Technical Field
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[0001] The present invention relates to a front fork provided with a damping force generating device and a pressurizing device.
Background Art
[0002] Saddle-riding type vehicles typified by motorcycles and three-wheeled vehicles are provided with a hydraulic shock absorber that connects the axle and the vehicle body to absorb vibrations from the road surface. The prior art related to such a hydraulic shock absorber is disclosed in Patent Document 1.
[0003] The hydraulic shock absorber disclosed in Patent Document 1 is a front fork provided on a motorcycle. This front fork includes an outer tube and an inner tube that is partially arranged to be able to advance and retreat inside the outer tube, and is provided with a telescopic body that can be telescoped as a whole.
[0004] Inside the telescopic body, 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 are arranged.
[0005] When an impact is applied from the wheel to the telescopic body, the piston moves, and oil (hydraulic oil) flows back and forth between the first oil chamber and the second oil chamber through the communication holes formed in the piston, thereby generating a damping force due to the flow path resistance of the oil, and the front fork absorbs the impact.
Prior Art Documents
Patent Documents
[0006]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0007] The front fork further includes a damping force generating device that communicates with a lower second oil chamber and is capable of generating damping force, and a pressurizing device that can pressurize the oil in the damping force generating device. By including the damping force generating device and pressurizing device, the responsiveness of the damping force can be improved. However, a front fork equipped with a damping force generating device and pressurizing device has a higher manufacturing cost.
[0008] The present invention aims to provide a front fork that can reduce manufacturing costs. [Means for solving the problem]
[0009] As a result of diligent research, the inventors have found that a front fork can be provided that includes a bracket holding the axle-side end of an extendable body, a control valve communicating with the second oil chamber of a cylinder, and a pressurizing device capable of pressurizing the oil inside the control valve, wherein the pressurizing device includes a pressurizing member capable of pressurizing the oil by contacting it, and a pressurizing source that applies force to the pressurizing member so that the pressurizing member can pressurize the oil, the pressurizing member and the pressurizing source are housed in a storage hole formed integrally with the bracket, the centerline of the pressurizing device is at a different position from the axis of the extendable body, and manufacturing costs can be reduced. The present invention was completed based on these findings.
[0010] According to this disclosure, a front fork is provided, comprising: 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 inside 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 move back and forth relative to each other, and the outer tube and the inner tube as a whole expand and contract, causing the piston in the cylinder to move and generate a damping force; a bracket holding the axle-side end of the expandable body; a control valve communicating with the second oil chamber; and a pressurizing device capable of pressurizing the oil inside the control valve, wherein the pressurizing device comprises a pressurizing member capable of contacting and pressurizing the oil, and a pressurizing source that applies force to the pressurizing member so that the pressurizing member pressurizes the oil, wherein the pressurizing member and the pressurizing source are housed in a housing hole formed integrally with the bracket, and the centerline of the pressurizing device is at a different position from the axis of the expandable body. [Effects of the Invention]
[0011] According to this disclosure, it is possible to provide a front fork that is easy to attach to the vehicle body. [Brief explanation of the drawing]
[0012] [Figure 1] This is a side view of a motorcycle equipped with a front fork according to an embodiment. [Figure 2] Figure 1 is a cross-sectional view of the area around the front wheel axle of a two-wheeled vehicle. [Figure 3] This describes the position of the control valve and pressurizing device relative to the bracket that holds the expandable body. [Modes for carrying out the invention]
[0013] Embodiments 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.
[0014] <Example 1> Refer to Figure 1. The shock absorber 10 is, for example, a front fork used in an off-road type motorcycle 100 (saddle-type vehicle 100). Hereafter, the shock absorber 10 will be referred to as the front fork 10 in the explanation.
[0015] The motorcycle 100 comprises a body 111, an engine 112 as a power source supported at the lower center of the body 111, left and right front forks 10 (only the right front fork 10 is shown in Figure 1) provided on the left and right front of the body 111 to absorb shocks from uneven road surfaces, a front wheel 114 sandwiched between the lower ends of these front forks 10 and rotatably supported, a handle pipe 115 positioned above the front forks 113 to steer the front wheel 114, a seat 116 provided above the engine 112 where the rider sits, a swing arm 117 extending from the rear of the body 111 toward the rear and swingable relative to the body 111, a rear wheel 118 rotatably supported by the rear end of the swing arm 117, and left and right rear suspensions 113 (only the right rear suspension 113 is shown in Figure 1) spanning from the rear of the body 111 to the swing arm 117.
[0016] The left and right front forks 10 have the same configuration. The following description focuses on the right front fork 10; the description of the left front fork will be omitted. Note that the left and right front forks 10 can have different configurations depending on the purpose.
[0017] [Stretchable body, outer tube, inner tube] Refer to Figure 2. The front fork 10 is equipped with a telescopic body 11 that can extend and retract in the vertical direction. The telescopic body 11 comprises a cylindrical outer tube 12 that extends in the vertical direction and a cylindrical inner tube 13 that is partially located inside the outer tube 12. The overall length (vertical dimension) of the telescopic body 11 changes as the outer tube 12 and the inner tube 13 move back and forth in the vertical direction relative to each other.
[0018] [Cylinder, piston, rod] The telescopic body 11 includes a cylindrical cylinder 21 provided inside the inner tube 13, a piston 24 that divides the inside of the cylinder 21 into an upper (vehicle body side) first oil chamber 22 and a lower (axle side) second oil chamber 23, and a rod 25 that extends upward from the piston 24.
[0019] Between the inner peripheral surface of the inner tube 13 and the outer peripheral surface of the cylinder 21, a compression coil spring 14 that applies a force to move in opposite directions with respect to the inner tube 13 and the outer tube 12, and a cylindrical support member 15 that supports the compression coil spring 14 are arranged.
[0020] The lower end of the cylinder 21 is closed by a first closing member 26. The first closing member 26 has an extension portion 27 that extends downward. The lower end of the inner tube 13 is closed by a second closing member 28. The extension portion 27 of the first closing member 26 penetrates the second closing member 28 and is supported by the second closing member 28.
[0021] [Function of the telescopic body] When the telescopic body 11 expands and contracts due to the impact from the wheel and the force of the compression coil spring 14, the piston 24 inside the cylinder 21 moves. Oil (hydraulic oil) flows between the first oil chamber 22 and the second oil chamber 23 through the communication holes formed in the piston 24, thereby generating a damping force due to the flow path resistance of the oil.
[0022] If a damping force can be generated by the expansion and contraction of the telescopic body 11, the internal configuration of the telescopic body 11 is not limited to the embodiment. Further, 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 for a conventional front fork in which the outer tube 12 is located below the inner tube 13.
[0023] [Bracket] The axle-side end 11a of the telescopic body 11 is held by a bracket 16. The bracket 16 has a first holding hole 31 for holding the axle-side end 11a and a support hole 32 capable of supporting the axle (the bracket 16 can also be said to be a member that connects the telescopic body 11 and the axle). A female thread is formed on the end face of the extension 27 that protrudes from the second closing member 28. The axle-side end 11a is fixed to the bracket 16 by fastening this female thread with a bolt 29.
[0024] The caliper support section 40 includes a control valve 50 whose interior is in communication with the second oil chamber 23, and a pressurizing device 60 capable of pressurizing the oil inside the control valve 50.
[0025] [Control valve] The control valve 50 can employ a well-known configuration as long as its interior is in communication with the second oil chamber, such as a damping force generating valve, a damping force adjustment valve, a flow control valve, or a switching valve, which generates a damping force by causing oil to move between the oil chambers in the control valve 50 as the expandable body 11 expands and contracts. The control valve 50 is held in a second retaining hole 41 formed in the bracket 16. The opening 41a of the second retaining hole 41 faces the same direction as the support surfaces 43 and 46, which will be described later.
[0026] [Pressurizing device] The pressurizing device 60 includes a free piston 61 (pressurizing member) that comes into contact with 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 can apply pressure to the oil.
[0027] The free piston 61 and the gas 62 are housed in a roughly cylindrical storage hole 64 formed integrally with the bracket 16. The inner circumferential surface 65 of the storage hole 64 is a surface on which the outer circumferential surface of the free piston 61 can slide. The space defined by the inner circumferential surface 65 of the storage hole 64 is a space in which the gas 62 can be filled.
[0028] The opening 64a of the storage hole 64 faces the same direction as the support surfaces 43 and 46, which will be described later. This opening 64a of the storage hole 64 is closed by a cap 63. The cap 63 has an injection valve 66 into which gas 62 can be injected into the inside of the storage hole 64.
[0029] The pressurizing device 60 may be a combination of a bladder (pressurizing member) and gas 62, or a combination of a free piston 61 and a compression coil spring (pressurizing source), and its configuration is not limited to the embodiment.
[0030] [Support surface] The bracket 16 is equipped with a caliper support portion 40 capable of supporting a brake caliper 70. The caliper support portion 40 consists of an upper first projection 42 and a lower second projection 45 that project radially outward from the edge of the bracket 16 toward the axle. The first projection 42 and the second projection 45 are spaced apart from each other so as to support the first end 71 and the second end 72 located at both ends of the brake caliper 70.
[0031] The first end portion 71 is fixed to the first projection 42 by a bolt 73 (fastening member). More specifically, the first projection 42 has a first support surface 43 that contacts the first end portion 71 and is capable of supporting the brake caliper 70. The first support surface 43 has a first fastening hole 44 that is fastened with the bolt 73.
[0032] The second end portion 72 is fixed to the second projection 45 by a bolt 73 (fastening member). More specifically, the second projection 45 has a second support surface 46 that contacts the brake caliper 70 and is capable of supporting the brake caliper 70. The second support surface 46 has a second fastening hole 47 that is fastened with the bolt 73.
[0033] [Position of control valve and pressurizing device relative to the interface] Refer to Figure 3. The plane including the first support surface 43 and the second support surface 46 is referred to as the boundary surface B. With boundary surface B as the boundary, the side where the caliper support portion 40 is located is referred to as the support portion side, and the side where 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.
[0034] [Position of control valve and pressurizing device relative to the center line of the fastening hole] The control valve 50 and the pressurizing device 60 are located between the first centerline C1 of the first fastening hole 44 and the second centerline C2 of the second fastening hole 47.
[0035] [Location of control valve and pressurizer] The pressurizing device 60 and the control valve 50 are arranged in parallel. For example, as shown in Figure 3, when viewed from a direction along the axis AX of the axle, the pressurizing device 60 and the control valve 50 are aligned 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 (the line extending in the pressurizing direction) and the center line Cd of the control valve 50 (the center line of the cylindrical case) are not necessarily located on the same plane.
[0036] 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 such that they are oblique to the first center line C1 and the second center line C2.
[0037] A portion of the control valve 50 is located below the expandable body 11. That is, the control valve 50 extends into the space below the expandable body 11 within the bracket 16.
[0038] [Effects of the Example] Firstly, the bracket 16 has a storage hole 64. The outer circumferential surface of the free piston 61 is slidable against the inner circumferential surface 65 of the storage hole 64. Gas 62 is filled into the space defined by the inner circumferential surface 65 of the storage hole 64. Prior art pressurizing devices include a pipe that houses the free piston and into which gas can be filled. The pressurizing device 60 of this embodiment does not require such a pipe. This reduces the number of parts that make up the pressurizing device 60 and lowers the manufacturing cost of the front fork.
[0039] Furthermore, the bracket of the prior art requires an insertion hole for inserting the lower end of the pipe. 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 will not be higher compared to the bracket of the prior art.
[0040] In addition, the centerline Cd of the pressurizing device 60 is located at a different position from the axis C of the telescopic body 11. That is, the pressurizing device 60 is not built into the telescopic body 11. Generally, some front forks have the centerline of the pressurizing device overlapping with the axis of the telescopic body, and the pressurizing device is built into the end of the telescopic body. Compared with such a front fork, in this embodiment, the axial dimension of the telescopic body 11 can be shortened, thus making the front fork 10 smaller.
[0041] Secondly, the control valve 50 is provided on the bracket 16. Compared to an expandable body that incorporates the control valve, the dimensions of the expandable body 11 can be shortened.
[0042] Thirdly, both the control valve 50 and the pressurizing device 60 are located entirely on the caliper support side, with the interface B as the boundary. That is, neither the control valve 50 nor the pressurizing device 60 protrudes toward the caliper side. Neither the control valve 50 nor the pressurizing device 60 interferes with the mounting of the brake caliper 70.
[0043] Note that the positions of the control valve 50 and the pressurizing device 60 are not limited to the example shown in Figure 3, as long as the entire structure is located on the support side. The orientation of the control valve 50 and the pressurizing device 60 (the direction in which the centerlines Cp and Cd extend) can be changed as appropriate, and the control valve 50 and the pressurizing device 60 may also be arranged in a direction along the axis AX of the shaft member (the front and back direction in Figure 3).
[0044] Fourth, the pressurizing device 60 and the control valve 50 are arranged in parallel. If the control valve 50 were arranged along the pressurizing direction of the pressurizing device 60 (arranged in series), the pressurizing device 60 and the control valve 50 as a whole would become longer. On the other hand, arranging the pressurizing device 60 and the control valve 50 in parallel makes them less likely to overlap with other devices or components.
[0045] 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 projection 42 and the second projection 45 are spaced apart from each other so as to support both ends 71 and 72 of the brake caliper 70. By arranging the control valve 50 and the pressurizing device 60 in the space created by this spacing, the space can be used effectively.
[0046] Furthermore, the present invention is not limited to the embodiments, provided that it achieves the function and effects of the present invention. In the embodiments, the bracket 16 is equipped with a caliper support portion 40, but the configuration of the present invention can also be applied to brackets without a caliper support portion 40 in single-sided brake models. [Industrial applicability]
[0047] The front fork of the present invention is suitable for use as a hydraulic shock absorber in a motorcycle. [Explanation of symbols]
[0048] 10…Front fork 11...Stretchable body 11a...Axle side end 12...Outer tube 13... Inner tube 21... Cylinder 22...No. 1 oil room 23…Second oil chamber 24... Piston 25… Rod 40... Caliper support 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 (pressure component) 62...Gas (pressure source) 64…Storage holes 70...Brake caliper 73... Bolt (fastening component) AX... Axle axis B…Boundary surface C...Axis of the expandable body C1...Centerline of the first fastening hole C2...Centerline of the second fastening hole Cp...Centerline of the pressurizing device D... Direction perpendicular to the direction of pressure
Claims
1. An expandable and contractible body comprising 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 inside 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 move back and forth relative to each other, and the outer tube and the inner tube as a whole expand and contract, causing the piston inside the cylinder to move and generating damping force, A bracket that holds the axle-side end of the aforementioned expandable body, A control valve communicating with the second oil chamber, The control valve is equipped with a pressurizing device capable of pressurizing the oil inside the control valve, The pressurizing device comprises a pressurizing member capable of pressurizing 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 are housed in a storage hole formed integrally with the bracket. The center line of the pressurizing device is at a different position from the axis of the expandable body. The control valve is provided on the bracket. The bracket is equipped with a caliper support portion capable of supporting a brake caliper, The caliper support portion has a support surface that contacts the brake caliper and is capable of supporting the brake caliper. A front fork in which the control valve and the pressurizing device are located on the caliper support side of the plane including the support surface, with the plane including the support surface serving as the boundary surface.
2. The front fork according to claim 1, wherein the control valve and the pressurizing device are arranged in parallel.
3. An expandable and contractible body comprising 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 inside 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 move back and forth relative to each other, and the outer tube and the inner tube as a whole expand and contract, causing the piston inside the cylinder to move and generating damping force, A bracket that holds the axle-side end of the aforementioned expandable body, A control valve communicating with the second oil chamber, The control valve is equipped with a pressurizing device capable of pressurizing the oil inside the control valve, The pressurizing device comprises a pressurizing member capable of pressurizing 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 are housed in a storage hole formed integrally with the bracket. The center line of the pressurizing device is at a different position from the axis of the expandable body. The control valve is provided on the bracket. The bracket is equipped with a caliper support portion capable of supporting a brake caliper, The caliper support portion has a first support surface and a second support surface that are in contact with the brake caliper and capable of supporting the brake caliper. With the plane including the first support surface and the second support surface as the boundary surface, the control valve and the pressurizing device are located on the caliper support side of the boundary surface. The control valve and the pressurizing device are arranged in parallel. The first support surface has a first fastening hole into which a fastening member capable of fixing the brake caliper can be fastened. The second support surface has a second fastening hole into which a fastening member capable of fixing the brake caliper can be fastened. An inverted front fork in which the control valve and the pressurizing device are located between the first center line of the first fastening hole and the second center line of the second fastening hole.