JPH0738775U - Damper device - Google Patents

Abstract

(57) [Abstract] [Purpose] To simplify the structure of the damping force generation mechanism and reduce the number of parts to reduce the cost. [Structure] Guide bushes 31 and 30 are provided on the inner peripheral portion of the outer tube 16 and the outer peripheral portion of the inner tube 15.
Are installed so that both tubes are slidable, the outer tube is provided with a taper pipe 41 formed in a taper shape toward the tip, and the inner tube tip inner peripheral portion is provided with a tapered tube free play. A piston body 38 to be fitted is installed, and this piston body is arranged corresponding to the tip end portion of the taper pipe in the stationary 1G state of the vehicle, and the first oil chamber 22A and the second oil chamber 22B are provided between the piston body and the taper pipe. The contraction-side flow path 43 communicating with the inner tube is formed, and the second side is formed on the inner tube.
The extension side flow path 45 that connects the oil chamber and the third oil chamber 22C is formed.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a damper device, and more particularly to a damper device suitable for being applied to a bicycle front fork assembly or a rear cushion unit.

[0002]

[Prior art]

 Some conventional mountain bicycles have front wheels supported by a front fork equipped with a cushioning mechanism and a damping force generating mechanism. This front fork connects a pair of left and right front fork assemblies with a steering bracket and supports the front wheels with both front fork assemblies.The front fork assembly has a built-in shock absorbing mechanism and damping force generating mechanism. ing.

As described in Japanese Patent Application Laid-Open No. 4-290626, the damping force generating mechanism is configured such that the outer tube and the inner tube forming the front fork assembly are filled with hydraulic oil and the inside of the tip of the inner tube is filled. A piston body is installed around the circumference, a compression side port and an expansion side port are formed in this piston body, and a compression side valve and an expansion side valve are installed at one open end of these ports, respectively. When hydraulic oil flows through the expansion side valve or the contraction side valve when the front fork assembly expands or contracts, the fluid resistance at this time generates a damping force.

[0004]

[Problems to be solved by the device]

 However, the conventional damping force generating mechanism described in the above publication requires a piston body, a compression side valve, an expansion side valve, a valve spring, and the like, which complicates the structure and therefore increases the number of parts. Furthermore, the piston body must be provided with the expansion side port and the contraction side port, which increases the mold cost or the processing cost. Moreover, since an expensive disc valve is used as the expansion side valve, the cost further increases.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a damper device that simplifies the structure of the damping force generation mechanism, reduces the number of parts, and reduces the cost. To do.

[0006]

[Means for Solving the Problems]

 According to this invention, a guide member is installed on the inner peripheral portion of the outer tube tip and the outer peripheral portion of the inner tube, and both tubes are slidably provided. The outer tube and the inner tube are filled with a working fluid. In addition, in the damper device that is provided with the damping force generation mechanism and can be arranged between the vehicle body and the axle, the outer tube is provided with a taper member that is tapered toward the tip. A piston body that is loosely fitted to the taper member is installed on the inner peripheral portion of the tip of the inner tube, and the piston body is arranged corresponding to the tip portion of the taper member when the vehicle is stationary. A first oil chamber is formed surrounded by the piston body and the outer tube, and a second oil chamber is formed surrounded by the inner tube. A third oil chamber is formed by being surrounded by the tube, the inner tube and the guide members, and a compression-side flow path is formed between the piston body and the taper member to connect the first and second oil chambers. The expansion tube that connects the second and third oil chambers is formed in the inner tube.

[0007]

[Action]

 Therefore, according to the damper device of the present invention, in the compression process of the damper device, the fluid resistance of the working fluid flowing from the first oil chamber to the second oil chamber is generated in the contraction side flow path between the taper member and the piston body. The contraction-side damping force is generated by the expansion device. Also, in the expansion process of the damper device, the expansion-side damping force is generated in the expansion-side flow path of the inner tube by the fluid resistance of the working fluid flowing from the third oil chamber to the second oil chamber. Occur.

As described above, the damping force generating mechanism of the damper device is a compression member formed of a taper member installed on the outer tube and a piston body installed on the inner circumference of the inner tube tip and loosely fitted to the taper member. Since it is composed of the side flow path and the expansion side flow path formed in the inner tube, the structure of the damping force generation mechanism is simple and easy to process, the number of parts is small, and no expensive disc valve is used. Therefore, the cost can be reduced.

[0009]

【Example】

 An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a front view showing a front fork to which an embodiment of the damper device according to the present invention is applied. FIG. 2 is a half sectional view showing a fork assembly of the front fork of FIG. FIG. 3 is an enlarged view showing a part of FIG. 2 in an enlarged manner.

As shown in FIG. 1, a front fork 10 is formed by connecting two front fork assemblies 11 by using a steering bracket 12 and a cross member 13, and at the lower end of each front fork assembly 11, an axle of a front wheel ( Both are not shown). The steering bracket 12 is provided with a steering shaft 14, and the steering shaft 14 is rotatably supported by a head pipe (not shown) of the vehicle body to be steerable. A handlebar (not shown) is fixed to the upper end of the steering shaft 14.

As shown in FIGS. 1 and 2, the front fork assembly 11 has an inner tube 15 and an outer tube 16 slidably configured. An axle support portion 17 that supports the axle of the front wheels is provided at the lower end portion (base end portion) of the outer tube 16. The upper end portion (base end portion) of the inner tube 15 is inserted into the insertion hole of the steering bracket 12 and then fixed by bolts to be joined to the steering bracket 12.

An enlarged diameter portion 18 is formed at the upper end portion (tip portion) of the outer tube 16, and a cross member holder 19 is provided below the enlarged diameter portion 18. The U-shaped cross member 13 is bridged over the cross member holder 19 of the two front fork assemblies 11. A brake lever (both not shown) provided with a brake pad is pivotally supported by the brake holder 21 on the cross member 13. The cross member 13 reinforces the lack of rigidity due to the front fork assembly 11 being divided into the inner tube 15 and the outer tube 16, and further supports the brake reaction force acting on the brake lever.

As shown in FIG. 2, the front fork assembly 11 has an inner tube 15 and an outer tube 16 each having an oil chamber 22 filled with working oil as a working fluid and an air chamber 23 filled with air. It is formed. The oil chamber 22 is divided into a first oil chamber 22A, a second oil chamber 22B, and a third oil chamber 22C as described later. A lower end portion of the oil chamber 22 is defined by a partition member 24 that is liquid-tightly installed at a substantially central portion of the outer tube 16 in the axial direction. The upper end of the air chamber 23 is closed by the closing member 25. Reference symbol L is an oil surface indicating the boundary between the oil chamber 22 and the air chamber 23.

The closing member 25 is fixed to the inner circumference of the upper portion of the inner tube 15, and the air valve 26 is screwed to the closing member 25. Air is supplied into the air chamber 23 or discharged from the air chamber 23 by using the air valve 26, and the initial spring load of the air spring reaction force is adjusted. The O-ring 27 is interposed between the inner tube 15 and the closing member 25, and the air chamber 23 is airtightly configured. Further, the valve cap 29 is fitted into the cap support 28 mounted on the upper end portion of the inner tube 15 to protect the air valve 26.

As shown in FIG. 3, a guide bush 30 as a guide member is fixed to the outer peripheral portion of the lower end of the inner tube 15 by a stopper ring 32. Further, a guide bush 31 as a guide member is press-fitted into the expanded diameter portion 18 of the outer tube 16. The inner bush 15 and the outer tube 16 are slidable by the guide bush 30 slidingly contacting the inner peripheral surface of the outer tube 16 and the guide bush 31 slidingly contacting the outer peripheral surface of the inner tube 15. The third oil chamber 22C is configured by being surrounded by both of the guide bushes 30 and 31, the inner tube 15 and the outer tube 16.

An oil seal 33 and a dust seal 34 are attached to the inner peripheral portion of the expanded diameter portion 18 of the outer tube 16. The oil seal 33 is locked by the seal washer 35 and the seal stopper ring 36. The oil seal 33 prevents oil from leaking from the third oil chamber 22C, and the dust seal 34 prevents dust from entering the third oil chamber 22C.

A bump rubber 37 is arranged on the upper surface of the partition member 24 installed on the outer tube 16. On the other hand, the piston body 38 is attached to the inner peripheral portion of the lower end of the inner tube 15. During the compression process of the front fork assembly 11, the lower end of the inner tube 15 and the piston body 18 contact the partition member 24 via the bump rubber 37, thereby defining the final end of the compression process. A rebound sheet 39 is fixed to the outer periphery of the axially central portion of the inner tube 15 by using a stopper ring 32, and the inner peripheral portion of the enlarged diameter portion 18 of the outer tube 16 and the guide bush 31. A rebound rubber 40 is attached below the. During the expansion process of the front fork assembly 11, the rebound seat 39 contacts the guide bush 31 via the rebound rubber 40, thereby defining the final end of this expansion process.

The partition wall member 24 is integrally formed with a tapered tube 41 as a tapered member. The taper pipe 41 is formed in a taper shape that is tapered toward the upper end (tip) of the outer tube 16, that is, its outer shape is gradually enlarged toward the lower end (base end) of the outer tube 16. In the stationary 1G state of the bicycle (gravity state when one rider rides with the vehicle stationary), the piston body 38 is loosely fitted to the upper end portion (tip portion) of the taper pipe 41, and these The first oil chamber 23 is formed by being surrounded by the outer peripheral surface of the taper pipe 41, the piston body 38 and the outer tube 16. Further, the second oil chamber 23B is formed by being surrounded by the inner tube 15, the piston body 38, and the taper pipe 38. Here, the inside 42 of the tapered pipe 41 is configured to communicate with the second oil chamber 23B.

A ring-shaped region between the outer peripheral surface of the taper pipe 41 and the inner peripheral surface of the piston body 38 is configured as a compression-side flow passage 43 that connects the first oil chamber 23A and the second oil chamber 23B. During the compression process of the front fork assembly 11, the volume of the first oil chamber 23A decreases and the pressure in the first oil chamber 23A rises, whereby the first oil chamber 23A contracts to the second oil chamber 23B. The hydraulic oil flows through the side flow path 43 (solid line arrow), and the fluid resistance at this time generates a damping force on the compression side.

The damping force by the contraction-side flow passage 43 has a speed-dependent characteristic that increases in proportion to the speed of the piston body 38, and the piston body 38 moves toward the base end (lower end) side of the taper pipe 41. The greater the position, the greater the position-dependent characteristic. Therefore, the damping force by the contraction side flow path 43 increases as the expansion and contraction movement of the front fork assembly 11 is fast and the expansion and contraction width is large.

The taper pipe 41 is further formed with a contraction side orifice 44 that connects the pipe interior 42 and the first oil chamber 23A. The contraction-side orifice 44 is formed so as to penetrate in the radial direction of the tapered pipe 41, and connects the first oil chamber 23A and the second oil chamber 23B via the pipe interior 42. During the compression process of the front fork assembly 11, the damping force on the compression side is also generated by the fluid resistance of the hydraulic oil (solid arrow) flowing from the first oil chamber 23A toward the pipe interior 42 through the compression side orifice 44.

As described above, during the compression process of the front fork assembly 11, the hydraulic oil in the first oil chamber 22A flows into the second oil chamber 23B through the compression side flow passage 43 and the compression side orifice 44, and the air chamber 23 is compressed and an air spring reaction force is generated. The compression process of the front fork assembly 11 is when an impact force acts on the front wheels to raise the outer tube 16, and the impact force is absorbed by the air spring reaction force.

Further, in the inner tube 15, an orifice that connects the third oil chamber 22C and the second oil chamber 22B is opened as an extension side flow passage 45. Since the volume of the third oil chamber 22C decreases during the expansion process of the front fork assembly 11, the pressure increase in the third oil chamber 22C causes the hydraulic oil to flow from the third oil chamber 22C to the second oil chamber 22B. Flow and fluid resistance at this time generate damping force on the extension side.

According to the above-described embodiment, in the compression process of the front fork assembly 11, the compression-side flow passage 43 between the taper pipe 41 and the piston body 38 flows from the first oil chamber 23A to the second oil chamber 23B. A damping force on the contraction side is generated by the fluid resistance of the hydraulic oil and the fluid resistance of the hydraulic oil flowing through the contraction-side orifice 44. Further, in the expansion process of the front fork assembly 11, the expansion-side passage 45 of the inner tube 15 is The extension side damping force is generated by the fluid resistance of the hydraulic oil flowing from the third oil chamber 22C to the second oil chamber 22B.

As described above, the damping force generating mechanism of the front fork assembly 11 is formed in the taper tube 41 and the contraction side flow passage 43 formed of the piston body 38 loosely fitted in the taper tube 41. Since it is composed of the contraction side orifice 44 and the expansion side flow passage 45 formed in the inner tube 15, the structure of the damping force generating mechanism is simple and easy to process, the number of parts is small, and the expensive disc is expensive. Since no valve is used, the cost can be reduced.

In the above embodiment, the contraction-side orifice 44 is formed in the taper pipe 41, but the contraction-side orifice 44 may be omitted. Further, in the above-mentioned embodiment, the front fork assembly 11 in which the front fork assembly 11 supports the axle by the outer tube 16 is described, but it is an inverted front fork in which the inner tube 15 supports the axle. Is also good. Furthermore, although the damper device according to the present invention is applied to the front fork in the above embodiment, it may be applied to the rear cushion unit.

[0027]

[Effect of device]

 As described above, according to the damper device of the present invention, the structure of the damping force generating mechanism can be simplified, the number of parts can be reduced, and the cost can be reduced.

[Brief description of drawings]

FIG. 1 is a front view showing a front fork to which an embodiment of a damper device according to the present invention is applied.

FIG. 2 is a half sectional view showing a fork assembly of the front fork of FIG.

FIG. 3 is an enlarged view showing a part of FIG. 2 in an enlarged manner.

[Explanation of symbols]

 10 front fork 11 front fork assembly 15 inner tube 16 outer tube 17 axle support 22 oil chamber 22A first oil chamber 22B second oil chamber 22C third oil chamber 23 air chamber 24 partition wall member 30 guide bush 31 guide bush 38 piston body 41 taper pipe 42 inside of tapered pipe 43 compression side flow path 44 compression side orifice 45 expansion side flow path

Claims (2)

[Scope of utility model registration request] 1. A guide member is installed on the inner peripheral portion of the tip of the outer tube and the outer peripheral portion of the tip of the inner tube so that both tubes are slidably provided, and the outer tube and the inner tube are filled with a working fluid. Along with
In a damper device in which a damping force generating mechanism is installed and can be arranged between a vehicle body and an axle, a taper member that is tapered toward the tip is installed on the outer tube, and A piston body that is loosely fitted to the taper member is installed in the peripheral portion, and the piston body is arranged corresponding to the tip end portion of the taper member in the stationary 1G state of the vehicle, and the taper member, the piston body, and the outer tube. To form a first oil chamber, surrounded by the inner tube to form a second oil chamber, and surrounded by the outer tube, the inner tube, and both guide members to form a third oil chamber. A compression-side flow path that connects the first and second oil chambers is formed between the piston body and the taper member, and the inner tube has the second and third oil chambers. Damper apparatus characterized by extension side flow path which communicates is formed. 2. The taper member has a tubular shape, and a through passage extending in the radial direction is formed in the taper member, and the first and second oil passages are connected to each other through the through passage. The damper device described in.