JPH0714241U - Front fork body mounting structure - Google Patents

Abstract

(57) [Abstract] [Purpose] Disperses the shear stress at the lower end of the vehicle body side bracket and prevents the bending rigidity of the CFRP tube from decreasing. [Structure] The upper and middle portions of the outer peripheral surface of a CFRP tube 13 forming the outer peripheral surface of the outer tube 1 are provided with a collar member 1.
It is held by the upper bracket 17 and the under bracket 18 via 5, 16 and the skirt portion 16c of the collar member 16 is formed shorter than the width of the under bracket 18.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a mounting structure for mounting a front fork of a motorcycle on a vehicle body side, and more particularly to a vehicle mounting structure for a front fork having a carbon fiber reinforced plastic (hereinafter referred to as “CFRP”) tube provided on an outer peripheral surface of an outer tube.

[0002]

[Prior art]

 Conventionally, the front fork of a motorcycle has been configured such that the upper fork and the middle of the front fork's outer tube are inserted through the holding parts of the upper bracket and the under bracket where the central part is attached to the steering shaft, and the front part of each bracket is It is attached to the vehicle body by tightening and holding the outer tube.

By the way, in the front fork, an axial load and a bending load in a direction orthogonal to the axial direction are applied to the axle mounting portion as disclosed in Japanese Patent Publication No. 59-46832, so that the outer peripheral surface of the front fork is applied. When an outer tube provided with a CFRP tube (see Japanese Patent Laid-Open No. 59-53288) is used, the CFRP tube has fibers arranged in the axial direction in order to increase the bending load.

By the way, the bending load causes compressive stress on the front surface of the tube attached to the vehicle body side, tensile stress on the rear surface, and shear stress in the direction orthogonal to the axial direction on the portion held by the bracket. Is extremely weak against shear loads, there is a risk of shear stress concentrating on the lower front edge of the bracket and breaking the tube.

Further, as disclosed in Japanese Utility Model Publication No. 44-180, a metal cylinder is fitted between the bracket and the tube, and the metal cylinder is projected from the lower portion of the bracket for a considerable length of time. , It is known to disperse the stress concentration just below the bracket.

[0006]

[Problems to be solved by the device]

 By the way, it is known that when the L / d value (span / diameter) becomes smaller, the bending rigidity and bending strength of a CFRP tube are greatly reduced due to the influence of shearing force. If it is projected much longer than the bracket like a metal tube interposed between the CFRP tube and the CFRP tube, it will be weak against bending, depending on the rigidity of the collar.

[0007]

[Means for Solving the Problems]

 In order to solve the above problems, the present invention provides a CFRP tube on at least an outer peripheral surface of an outer tube, holds the outer peripheral surface of the CFRP tube by a vehicle body bracket via a collar member, and at the same time, mounts a skirt portion of the collar member. The width is smaller than the width of the bracket on the vehicle body side.

[0008]

[Action]

 The outer peripheral surface of the CFRP tube is held by the bracket on the vehicle body side through the collar member, and the skirt member of the color member is formed to be shorter than the width of the bracket on the vehicle body side. Prevent the decrease of.

[0009]

【Example】

 Embodiments of the present invention will be described below with reference to the accompanying drawings. Here, FIG. 1 is a half cross-sectional view of a front fork to which the vehicle mounting structure for a front fork according to the present invention is applied, FIG. 2 is a perspective view of a collar member of FIG. 1, and FIG. 3 is an enlarged view of a main part of the outer tube of FIG. A sectional view and FIG. 4 are enlarged sectional views of a CFRP tube of the outer tube.

In the front fork 1, an inner tube 3 is slidably inserted into the outer tube 2 from below, an axle mounting bracket 4 is screwed to a lower end portion of the inner tube 3, and a bottom portion is further inserted into the inner tube 3. The rod tube 5 is installed upright, the upper end of the guide tube 7 is attached to the upper cap 6 screwed to the upper end of the outer tube 2, and the upper cylinder tube 8 is hung from the lower end of the guide tube 7 to lower the bottom tube. It faces the outer circumference of the rod tube 5.

A hollow rod 9 having an upper end attached to the upper cap 6 faces the inside of the upper cylinder tube 8, a damping force generating piston 10 is attached to a lower end of the hollow rod 9, and a bottom rod tube A damping force generating piston 11 which is in sliding contact with the inner peripheral surface of the upper cylinder tube 8 is mounted on the upper end of the upper cylinder 5.

The outer tube 2 is provided with a CFRP tube 13 formed by winding and adhering a sheet-shaped CFRP around the outer peripheral surface of an inner pipe 12 made of an Mg alloy. The front fork 1 holds the upper end portion and the intermediate portion of the CFR P tube 13 forming the outer peripheral surface of the outer tube 2 by sandwiching them between the upper bracket 17 and the under bracket 18 via the collar members 15 and 16, and It is installed on the side. The collar members 15 and 16 may be fitted or adhered to the outer peripheral surface of the CFRP tube 13.

The collar member 15 has a slit (not shown) formed in the axial direction, and a collar 15a for positioning the mounting position of the upper bracket 17 on the outer peripheral portion. Further, as shown in FIG. 2, a slit 16a is formed in the collar member 16 in the axial direction, and a collar 16b for positioning the mounting position of the under bracket 18 is formed on the outer peripheral portion. Is formed such that the axial length of the skirt portion 16c projecting from the lower end of the under bracket 18 is shorter than the width (axial length) of the under bracket 18, and the axial thickness of the lower end portion of the skirt portion 16c becomes thin. The inclined portion 16d is formed.

Further, as shown in FIG. 3, the CFRP tube 13 of the outer tube 1 has a taper portion 13 a formed in an axial direction at a lower end portion which is an axial end portion, and a taper portion also at a corresponding portion of the inner pipe 12. 12a is formed so that the sheet-shaped CFRP can be bonded to the outer peripheral surface of the inner pipe 12 reliably and without a gap.

As shown in FIG. 4, this CFRP tube 13 has a self-adhesive glass fiber (GF) layer 21 from the innermost peripheral side, four 0 ° layers 22 to 25, and three 90 ° layers. 26 to 28 and a carbon fiber (CF) fabric layer 29 containing a fabric are sequentially laminated.

As described above, the CFR tube 13 forming the outer peripheral surface of the outer tube 2 is held by the brackets 17 and 18 via the collar members 15 and 16, and particularly, the collar member interposed between the CFR tube 13 and the under bracket 18 is provided. Since the skirt portion 16c is formed to be shorter than the width of the under bracket 18 in the axial direction, the shear stress applied to the lower end portion of the under bracket 18 can be dispersed and the bending rigidity is not reduced.

[0017]

[Effect of device]

 As described above, according to the present invention, the outer peripheral surface of the CFRP tube is held by the bracket on the vehicle body side through the collar member, and the skirt member of the collar member is formed shorter than the width of the bracket on the vehicle body side. Disperses the shear stress of the part and prevents the decrease of bending rigidity, which improves the durability.

[Brief description of drawings]

FIG. 1 is a half sectional view of a front fork to which a vehicle mounting structure for a front fork according to the present invention is applied.

FIG. 2 is a perspective view of the collar member of FIG.

FIG. 3 is an enlarged sectional view of a main part of the outer tube of FIG.

FIG. 4 is an enlarged sectional view of a CFRP tube as an outer tube.

[Explanation of symbols]

1 ... Front fork, 2 ... Outer tube, 3 ... Inner tube, 12 ... Inner pipe, 13 ... CFRP tube, 15, 16 ... Collar member, 16c ... Skirt part,
16d ... inclined part, 17 ... upper bracket, 18 ... under bracket.

Claims (2)

[Scope of utility model registration request] 1. A vehicle body mounting structure for a front fork in which an outer tube is slidably inserted into an outer tube and the front fork is mounted on a vehicle body while holding an outer peripheral surface of the outer tube by a vehicle body side bracket. A carbon fiber reinforced plastic tube is provided on at least an outer peripheral surface of the outer tube, and the outer peripheral surface of the carbon fiber reinforced plastic tube is held by the vehicle body side bracket via a collar member, and a skirt portion of the collar member. Is formed to be shorter than the width of the bracket on the vehicle body side. 2. The vehicle body mounting structure for a front fork according to claim 1, wherein an inclined portion whose thickness is reduced in the axial direction is formed at an end portion of the collar member.