JP2006057781A - Front fork with built-in damper - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To permanently secure workability and stable damping force generating state in a double rod damper incorporated in an axial part. <P>SOLUTION: In this front fork with a buit-in damper wherein a tip of one rod 13 of a pair of rod bodies 13, 14 connected at their base ends with both sides of a piston body 12 incorporating slidably the double rod damper 10 mounted on the axial part in a cylinder body 11 and projecting their distal ends to the external in the axial direction of the cylinder body 11 is connected with a closed end-side of an outer cylinder 1, and a tip of the other rod body 14 is separated from a closed end side of an inner cylinder 2, the sylinder body 11 connects an end part 11a where one rod body 13 is penetrated, with an opened end part 2b of the inner cylinder 2 in such a state that the end part where the other rod body 14 is penetrated, is separated from the inner cylinder 2. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an improvement of a damper built-in front fork.

  For example, as disclosed in Patent Document 1, when a front fork mounted on the front wheel side of a two-wheeled vehicle incorporates a double rod type damper, this damper is, in principle, a single rod. Compared to a type damper, a reservoir is not required, so a stable damping force can be expected without fear of aeration.

Therefore, in a damper built-in front fork in which this double rod type damper is housed in a shaft core inside a so-called fork main body formed of an outer cylinder and an inner cylinder, the inner cylinder with respect to the outer cylinder The road surface vibration can be absorbed by the operation of the above-described damper at the time of the expansion / contraction operation in which the stagnation occurs.
Japanese Utility Model Publication No. 1-80842

  However, in the damper built-in front fork disclosed in Patent Document 1 described above, it may be pointed out that there is a risk that the operating performance of the double rod type damper may not be ensured due to continued use.

  That is, when the front fork is mounted on a two-wheeled vehicle, the upper end side is the fixed side, while the lower end is the free end. In a state where the lower end is always pushed forward, that is, the inner cylinder projecting from the outer cylinder is expanded and contracted under a situation where the inner cylinder is bent more greatly than the outer cylinder.

  Therefore, for example, when an external force is input that threatens the mechanical strength of the inner cylinder and the inner cylinder is greatly bent, the sealing performance of the fork main body is reduced due to the bending, or the outer cylinder is The slidability with respect to the cylinder may be deteriorated.

  Not only when the inner cylinder is bent, but it is connected to the double rod type damper that is housed in the shaft core portion of the fork main body, that is, one end is connected to either the outer cylinder or the inner cylinder and the other. If the damper is connected to either the outer cylinder or the inner cylinder, the end of the shaft core is bent, the slidability of the damper may be hindered, and the damping characteristics may not be stabilized.

  The present invention was devised in view of such a current situation, and the object of the present invention is that even if the inner cylinder is bent due to continuation of use or the like, the shaft core portion is accommodated. The objective is to provide a damper built-in front fork that is guaranteed to ensure the operational performance of a double rod type damper and to improve its versatility.

  In order to achieve the above object, the structure of the damper built-in type front fork according to the present invention is basically in claim 1 and the opening end side of the inner cylinder can be projected and retracted in the opening end side of the outer cylinder. And a double rod type damper is accommodated in the inner shaft core portion formed by the outer cylinder and the inner cylinder, and the damper is slidably accommodated in the cylinder body and the cylinder body. Each of the piston bodies to be mounted has a pair of rod bodies whose respective base ends are connected to each other and projecting to the outside in the axial direction of the cylinder body. In the damper built-in front fork in which the tip of the rod body is connected to the closed end side of the outer cylinder and the tip of the other rod body is separated from the closed end side of the inner cylinder, the cylinder body is connected to the other rod body. Penetration Thereby to interlocking the open end of the inner cylinder end portion through which the one of the rod member under a state of being separated from the inner tube ends and composed.

  More specifically, in claim 2, an extending portion that is coaxial with the cylinder body is extended to an end portion that penetrates one rod body in the cylinder body. It is assumed that the end is connected to the open end of the inner cylinder.

  Therefore, in the first aspect of the invention, when the inner cylinder is bent with respect to the outer cylinder in the fork body, the inner cylinder is bent because the portion protruding from the outer cylinder is larger than the outer cylinder. However, the opening end portion of the inner cylinder that is inserted inside the opening end side of the outer cylinder is maintained in a state along the outer cylinder.

  Therefore, the shaft core wire in the double rod type damper having the cylinder body connected to the opening end portion of the inner cylinder is maintained in a state of being coincident with the shaft core line of the outer cylinder without being bent. Even if it becomes in a state where it is inclined with respect to the axial line of the inner cylinder which is bent, the axial line in the damper is not bent and the operation performance is guaranteed.

  In the invention of claim 2, since the end of the cylinder body is connected to the open end of the inner cylinder via the extension, the suspension spring is compared with the case where there is no extension. As a result, it is possible to sufficiently secure the space in which the coil is disposed, and it is possible to absorb the influence of the bending that is generated in the inner cylinder by the extending portion, and it is possible to reduce the influence of the bending on the damper.

  As a result, according to the present invention, in the fork main body, even if the inner cylinder is greatly bent due to continued use or the like, the operation performance of the double rod type damper that is accommodated in the shaft core portion is guaranteed. It will be.

  Hereinafter, the present invention will be described based on the illustrated embodiment. In the damper built-in front fork according to the present invention, as shown in FIG. 1, the so-called fork main body uses the outer cylinder 1 as a vehicle body side tube, The inner cylinder 2 is used as a wheel side tube, and the inner cylinder 2 is set to be an inverted type in which the opening end side of the inner cylinder 2 is inserted into the opening end side of the outer cylinder 1 so as to be able to protrude and retract.

  At this time, a suspension spring 3 is arranged between the outer cylinder 1 and the inner cylinder 2 and the fork main body is urged in the extending direction by the urging force of the suspension spring 3. One end of the suspension spring 3 is carried by a cylinder body 11 in a double rod type damper 10 which will be described later, and the other end is locked via a spring receiver 4 to a head portion 1a on the closed end side of the outer cylinder 1. It is supposed to.

  Incidentally, when this fork body is mounted on the front wheel side of the two-wheeled vehicle, a handle is connected to the upper end side of the outer cylinder 1 via a bracket and the front wheel is connected to the lower end side of the inner cylinder 2 (not shown). become.

  In this front fork, the inner side of the fork main body has a configuration of a double rod type damper that is accommodated in a shaft core portion to be described later, and is set in a reservoir chamber R. The reservoir chamber R is an oil surface. It has an air chamber A bordering on O.

  By the way, in this damper built-in type front fork, the double rod type damper 10 is accommodated in the shaft core portion of the fork main body, that is, the inner shaft core portion formed by the outer cylinder 1 and the inner cylinder 2. However, the damper 10 has a cylinder body 11 and a piston body 12 slidably housed in the cylinder body 11, and the base ends of the damper body 10 are connected to both sides of the cylinder body 11. It has a pair of rod bodies 13 and 14 protruding outside in the axial direction.

  At this time, in the damper 10, the tip of one rod body 13 forming the pair of rod bodies 13, 14 is on the closed end side of the outer cylinder 1, that is, in the drawing, the head portion of the outer cylinder 1. While being connected to 1a, the tip of the other rod body 14 is separated from the closed end side of the inner cylinder 2, that is, from the bottom portion 2a of the inner cylinder 2 in the drawing.

  Incidentally, the piston body 12 that is slidably accommodated in the cylinder body 11 defines one oil chamber R1 and the other oil chamber R2 in the cylinder body 11, and communicates both of these oil chambers R1 and R2. A damping valve 12a that generates a damping force having a predetermined magnitude when the hydraulic oil passes while being allowed is provided.

  By the way, in this invention, the above-described double rod type damper 10 separates the end portion through which the cylinder body 11 penetrates the other rod body 14 from the inner cylinder 2, that is, from the bottom portion 2a of the inner cylinder 2. In the separated state, the end 11a of the cylinder body 11 that penetrates one rod body 13 is linked to the open end 2b of the inner cylinder 2.

  That is, as shown in the figure, an extension portion 15 that is coaxial with the cylinder body 11 is extended to an end portion 11 a that penetrates one rod body 13 in the cylinder body 11, and an end portion of the extension portion 15 is provided. Is connected to the open end 2b of the inner cylinder 2.

  In this way, the end 11a of the cylinder body 11 is connected to the opening end 2b of the inner cylinder 2 via the extending portion 15, so that the end of the cylinder body 11 does not have the extending portion 15. Compared to the case where the portion 11a is connected to the opening end 2b of the inner cylinder 2, the cylinder body 11 can be separated from the opening end 2b of the inner cylinder 2, and the portion is expressed in the inner cylinder 2 accordingly. It is possible to prevent the cylinder body 11 from being affected by the bending.

  From the above, the opening end 2b of the inner cylinder 2 does not protrude from the outer cylinder 1 to the outside. Therefore, even if the inner cylinder 2 is bent, the opening end 2b of the inner cylinder 2 is bent. Therefore, even if the cylinder body 11 is directly connected to the opening end portion 2b of the inner cylinder 2 without the extending portion 15 interposed, there is no problem in principle.

  However, in the case where the cylinder body 11 is set to be directly linked to the opening end 2b of the inner cylinder 2 without the extending portion 15, there is a concern that the location of the suspension spring 3 cannot be secured. There may be disadvantages that cannot be described as realistic methods.

  Incidentally, although the extending portion 15 is formed in a cylindrical shape in the drawing, a plurality of holes 15 a that penetrate the wall and allow internal and external communication are opened in the axial direction of the extending portion 15. It is supposed to be worn.

  Therefore, as shown in the drawing, when the damper 10 is in the standard expansion / contraction state, that is, when the fork main body is in the standard expansion / contraction state, the oil level O is positioned inside the extension portion 15. In this case, the oil level O is also positioned outside the extended portion 15, that is, outside the damper 10.

  Incidentally, since this damper 10 is configured as a double rod type damper, in principle, a reservoir is not required as compared with the case where it is configured as a single rod type damper. However, from the viewpoint of so-called oil temperature compensation, the end portion of the cylinder body 11 through which the rod bodies 13 and 14 pass is the cylinder body of the hydraulic oil having an increased volume due to the rise in the oil temperature in the cylinder body 11. 11 is allowed to leak to the outside. Therefore, in the illustrated case, the outside of the damper 10 is a so-called reservoir chamber R.

  In this reservoir chamber R, an air chamber portion (not shown) bordering on the oil surface O is located on the upper end side of the outer cylinder 1 through a through hole (not shown) in the upper end portion of the extending portion 15. It is assumed that the main air chamber A formed inside communicates with the main air chamber A, but the air chamber portion (not shown) bordering on the oil surface O inside the extending portion 15 is connected to the outer periphery of the spring receiver 4 and the extending portion 15. It is assumed that the air chamber A communicates with the air chamber A through a gap that appears between the inner periphery of the fork body and the air chamber A is expected to exhibit an air spring effect when the fork body is extended and contracted.

  Therefore, in the above-described damper built-in front fork, a predetermined damping force is generated by the operation of the built-in double rod type damper 10 when the fork main body is extended and contracted.

  At this time, in the present invention, the damper 10 is held in a state suspended from the upper end portion which is the open end 2b of the inner cylinder 2 in the illustrated case. Even if the bending phenomenon appears in the portion protruding from 1, the opening end 2b of the inner cylinder 2 inserted through the outer cylinder 1 is maintained in a state along the outer cylinder 1. The shaft core line in the damper 10 connected to the open end 2b of the inner cylinder 2 is maintained in a state where the axis core line of the outer cylinder 1 does not bend without being bent, and the shaft core line in the damper 10 does not bend and operates. Performance is guaranteed.

  In the above description, the fork body in the front fork according to the present invention is formed in an inverted type in which the outer cylinder 1 is a vehicle body side tube and the inner cylinder 2 is a wheel side tube. In this case, although not shown, the outer cylinder 1 may be formed as an upright type in which the outer cylinder 1 is a wheel-side tube and the inner cylinder 2 is a vehicle-body-side tube. is there.

  At this time, in the double rod type damper 10 according to the present invention, one rod body 13 is connected to a so-called bottom portion which is a closed end portion of the outer cylinder 1, and the cylinder body 11 is an open end portion of the inner cylinder 2. The cylinder body 11 is separated so that the end portion from which the other rod body 14 projects is opposed to the head portion of the inner cylinder 2. It will be.

It is a figure which shows in principle the damper built-in type front fork by one Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Outer cylinder 2 Inner cylinder 2b Open end part 3 Suspension spring 4 Spring receiver 10 Damper 11 Cylinder body 11a End part 12 Piston body 13,14 Rod body 15 Extension part

Claims (3)

The open end side of the inner cylinder is inserted in the open end side of the outer cylinder so as to be able to protrude and retract, and a double rod type damper is accommodated in the inner shaft core portion formed by the outer cylinder and the inner cylinder, The damper has a pair of rods whose base ends are projected to the outside in the axial direction of the cylinder body while the base ends are connected to both sides of the cylinder body and the piston body slidably accommodated in the cylinder body. And the tip of one rod body forming the pair of rod bodies is connected to the closed end side of the outer cylinder, and the tip of the other rod body is separated from the closed end side of the inner cylinder. In the damper built-in type front fork, the end portion through which one rod body penetrates the cylinder body is connected to the opening end portion of the inner cylinder with the end portion through which the cylinder body penetrates the other rod body separated from the inner cylinder. It is characterized by That damper built-in front fork An extension portion that is coaxial with the cylinder body is extended at an end portion that penetrates one rod body in the cylinder body, and an end portion of the extension portion is connected to an opening end portion of the inner cylinder. Item 1. A damper-equipped front fork according to item 1. 2. The damper built-in front fork according to claim 1, wherein an end of the cylinder body through which the rod body penetrates allows leakage of hydraulic oil of an increased volume due to an increase in oil temperature inside the cylinder body to the outside of the cylinder body.

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