JP2009008128A - Bolt - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bolt with a square hole free of stagnation of rubbish, water, etc. and resistant to a tool abutting flaw that may be present. <P>SOLUTION: The bolt 20 is furnished with a groove 23 at each corner of the square hole 22 having inner peripheral surfaces in a regular polygonal shape in such a manner as to range over the whole depth of the hole and penetrating from the inner peripheral surface to the outside. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a bolt suitable for use as a fork bolt for a front fork of a motorcycle or the like.

  Conventionally, fork bolts for front forks include those having a hexagonal portion for a tightening tool on the outer periphery and those having a hexagonal hole.

  Fork bolts having a hexagonal portion on the outer periphery tend to be scratched (indentation) due to the tightening torque on the hexagonal portion during tightening with a tool, which may impair the appearance merchandise. Even if a tool made of resin or the like is used, it is difficult to prevent complete scratches if a certain tightening torque is applied. Furthermore, this problem of appearance merchantability is more pronounced with fork bolts that have been treated with colored anodized. Become.

  Fork bolts with hexagonal holes may cause inconveniences such as dust and water collecting in the hexagonal holes and deteriorating the appearance merchandise, and the hexagonal holes corroding due to the accumulated water. Yes. There is a disadvantage of unit price of fork cap and assembly work cost.

In addition, in the bolt described in Patent Document 1, as a hexagon socket head bolt that does not require a fork cap, several holes are provided on the side surface of the hexagon socket, and dust, water, and the like that enter the hexagon socket are discharged from this hole. The thing is disclosed.
62-92313

  In the bolt described in Patent Document 1, it is insufficient to discharge dust, water, or the like that has entered the bottom of the square hole by the hole provided on the side surface of the hexagonal hole. In addition, when tightening with a tool, the corners of the tool easily damage the side surface of the hexagonal hole (indentation), which impairs the appearance merchandise.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a bolt with a square hole that does not collect dust, water, or the like, and is not easily damaged by a tool.

  Another object of the present invention is to make it possible to use not only an inner diameter tool but also an outer diameter tool in a square hole bolt, thereby expanding the selection range of tightening and disassembling tools.

  The invention of claim 1 is a bolt in which a groove penetrating from the inner periphery to the outer periphery is provided in each corner portion of a square hole having a regular polygonal inner periphery over the entire hole depth.

  According to a second aspect of the present invention, in the first aspect of the present invention, the intermediate point of each surface forming the square hole is positioned closer to the center of the hole with respect to a straight line connecting both end points of the surface, and The plane including each and the intermediate point is used as the tool contact surface.

  According to a third aspect of the invention, in the first or second aspect of the invention, the outer periphery also forms a regular polygon.

  The invention of claim 4 is the fork bolt for a front fork according to any one of claims 1 to 3.

(Claim 1)
(a) In the bolt, a groove penetrating from the inner circumference to the outer circumference was provided at each corner of the square hole over the entire depth of the hole. Accordingly, dust, water, etc. entering the bottom of the square hole can be safely discharged via the groove. In addition, when tightening with a tool, the corner of the tool is positioned in the groove of the square hole, and the scratch is difficult to notice, but the corner of the tool hits the surface of the square hole. Can be avoided.

(Claim 2)
(b) In the bolt, the midpoint of each surface forming the square hole is positioned closer to the center of the hole with respect to the straight line connecting the both end points of the surface, and the plane including the midpoint and each of the end points of each surface A surface. Accordingly, when an appropriate clearance for facilitating insertion of the tool is formed between the tool and the square hole of the bolt, the tool is rotated by the clearance in the square hole, and then the tool is a square hole tool. The contact surface can be in surface contact and strong tightening can be performed, and the surface pressure between the tool surface and the square hole surface due to the tightening torque can be reduced, and the contact of the tool surface with the square hole surface can be reduced. Generation can be suppressed.

(Claim 3)
(c) In the bolt with a square hole, if the outer periphery is also a regular polygon, not only the inner diameter tool but also the outer diameter tool can be used, and the selection range of assembly and disassembly tools can be expanded. For example, at the factory assembly stage, an inner diameter tool such as an inner diameter wrench is used for the square hole so that the scratches are not noticeable. On the other hand, an outer diameter tool such as a spanner that is easily available can be used at the disassembly and assembly stage by the user.

(Claim 4)
(d) In the fork bolt for a front fork such as a motorcycle, the above (a) to (c) can be realized. In front forks for motorcycles, the center axis of the fork is usually arranged at an inclination angle of about 60 degrees with respect to the ground. Therefore, the bottom of the square hole of the bolt is inclined so that dust, water, etc. Can fall.

  1 shows a fork bolt provided on a front fork, (A) is a partially broken side view, (B) is a perspective view, FIG. 2 shows a fork bolt, (A) is a partially broken side view, (B) is a plan view, FIG. 3 shows a square hole component of a fork bolt, (A) is a plan view of the square hole component, (B) is a plan view of a square hole component having a tool contact surface, FIG. 4 is a plan view showing a contact state between the contact surface of the tool and the square hole.

  As shown in FIG. 1, the front fork 10 has an inner cylinder (or outer cylinder) 11 on the vehicle body side inserted into an outer cylinder (or inner cylinder) (not shown) on the wheel side. The male thread portion of the fork bolt 20 that is integrally formed into a single body by aluminum forging or the like is screwed. The fork bolt 20 seals the upper end opening of the inner cylinder 11 via the O-ring 12 and has a hydraulic shock absorbing structure built in the inner cylinder 11 and the outer cylinder.

  As shown in FIG. 1 and FIG. 2, the head 21 of the fork bolt 20 has the entire hole depth (the bottom surface of the square hole 22) at each corner of the square hole 22 having a regular hexagonal inner periphery. The groove 23 penetrating from the inner periphery to the outer periphery is formed over a range extending from 22A to the upper end surface 22B. At this time, the head 21 of the fork bolt 20 is divided into six in the circumferential direction by a groove 23 and is composed of six short pillar-shaped square hole components 24, and the square holes 22 are formed by the inner surface 25 of each square hole component 24. It forms one side of each of the six sides. The groove 23 becomes a discharge groove for dust or water entering the bottom of the square hole 22.

  The fork bolt 20 is screwed by inserting an inner diameter tool 1 (FIG. 4) such as a hexagon wrench into the square hole 22. At this time, the inner diameter tool 1 forms a clearance between the square hole 22 and the tool 1 can be easily inserted into the square hole 22.

  More specifically, the fork bolt 20 has, as shown in FIG. 3, each surface that forms one side of the six sides of the square hole 22, in other words, an inner side surface 25 that forms the square hole 22 of each square hole component 24. The intermediate point 26 </ b> C is positioned closer to the center of the square hole 22 with respect to the straight line connecting the left and right end points 26 </ b> A and 26 </ b> B of the inner surface 25. And in the inner surface 25, the left and right planes including the both end points 26A and 26B and the intermediate point 26C are defined as the left and right tool contact surfaces 25L and 25R. That is, the inner side surface 25 of each square hole component 24 is composed of left and right tool contact surfaces 25L, 25R. In each square hole component 24, the angle formed by the tool contact surfaces 25L and 25R with respect to the straight line connecting both end points 26A and 26B is preferably, for example, 0.5 to 1.5 degrees. The bending angle at the intermediate point 26C where 25R intersects is very small, and the tool contact surface 25L and the tool contact surface 25R together form one of the six sides of the square hole 22. At this time, each of the regular hexagonal tightening surfaces 1A of the inner diameter tool 1 forms the above-described clearance with each inner side surface 25 (tool contact surface 25L and tool contact surface 25R) of the square hole 22 of the fork bolt 20. When the inner diameter tool 1 is rotated by the clearance, the tightening surface 1A of the tool 1 contacts the tool contact surface 25L or the tool contact surface 25R (FIG. 4). The left tool contact surface 25L is a contact surface that the tool 1 contacts when the tool 1 is rotated clockwise, and the right tool contact surface 25R is a contact surface that the tool 1 contacts when the tool 1 is rotated counterclockwise.

  As shown in FIGS. 1 and 2, the fork bolt 20 has a regular hexagonal shape on the outer periphery of the head 21. In the present embodiment, the grooves 23 provided in the head portion 21 extend so as to form a straight line from each corner portion of the square hole 22 toward each corner portion of the outer periphery. Thereby, each square hole component 24 of the head 21 forms a pentagon (FIG. 3 (A)), and one side of the five sides of the square hole component 24 is defined as the inner side surface 25 (tool contact surface). 25L, 25R), the groove 23 is formed by two sides on both sides of the inner side surface 25, and the remaining two outer sides are outer side surfaces 27A, 27B intersecting each other at 120 degrees. One outer surface 27A and the other outer surface 27B of adjacent square hole components 24 are flush with each other across the groove 23, and each fastening surface forms one side of a regular hexagon of an outer diameter tool such as a spanner. It becomes the tool contact surface that hits.

According to the present embodiment, the following operational effects can be obtained.
(a) In the bolt 20, grooves 23 penetrating from the inner periphery to the outer periphery are provided at each corner of the square hole 22 over the entire hole depth. Therefore, dust, water, etc. entering the bottom of the square hole 22 can be safely discharged via the groove 23. In addition, when the tool 1 is tightened, the corner portion of the tool 1 is positioned in the groove 23 of the square hole 22, and the corner portion of the tool 1 is a square hole although the scratch is less noticeable. It is possible to avoid the occurrence of scratches on the 22 surfaces.

  (b) In the bolt 20, an intermediate point 26C of each surface 25 forming the square hole 22 is positioned closer to the center of the hole with respect to a straight line connecting both end points 26A, 26B of the surface 25, and both end points 26A of each surface 25, A plane including each of 26B and the intermediate point 26C is defined as a tool contact surface 25L, 25R. Therefore, when an appropriate clearance for facilitating insertion of the tool 1 is formed between the tool 1 and the square hole 22 of the bolt 20, after the tool 1 is rotated by the clearance in the square hole 22, The tool 1 comes into surface contact with the tool contact surfaces 25L and 25R of the square hole 22 to perform strong tightening, and the tightening surface 1A of the tool 1 and the tool contact surfaces 25L and 25R of the square hole 22 caused by the tightening torque. And the occurrence of contact scratches on the inner side surface 25 (tool contact surfaces 25L, 25R) of the square hole 22 by the tightening surface 1A of the tool 1 can be suppressed.

  (c) By making the outer periphery of the square hole bolt 20 have a regular hexagonal shape, not only the inner diameter tool 1 but also the outer diameter tool can be used, and the selection range of assembly and disassembly tools can be expanded. it can. For example, in the factory assembly stage, an inner diameter tool 1 such as an inner diameter wrench is used for the square hole 22 so as to make the scratches inconspicuous. On the other hand, an outer diameter tool such as a spanner that is easily available can be used at the disassembly and assembly stage by the user.

  (d) In the fork bolt 20 for a front fork such as a motorcycle, the above (a) to (c) can be realized. In the front fork 10 for a motorcycle, the center axis of the fork is usually arranged at an inclination angle of about 60 degrees with respect to the ground. Therefore, the bottom surface of the square hole 22 of the bolt 20 is inclined so that dust, water, etc. It becomes possible to drop from the groove 23.

  Although the embodiments of the present invention have been described in detail with reference to the drawings, the specific configuration of the present invention is not limited to these embodiments, and even if there is a design change or the like without departing from the gist of the present invention. It is included in the present invention. The present invention can be widely applied to polygonal bolts other than hexagon bolts.

1A and 1B show fork bolts provided on a front fork, in which FIG. 1A is a partially broken side view, and FIG. 1B is a perspective view. FIG. 2 shows a fork bolt, (A) is a partially broken side view, and (B) is a plan view. 3A and 3B show a square hole component of a fork bolt. FIG. 3A is a plan view of the square hole component, and FIG. 3B is a plan view of the square hole component having a tool contact surface. FIG. 4 is a plan view showing a contact state between the contact surface of the tool and the square hole.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Front fork 20 Fork bolt 22 Square hole 23 Groove 24 Square hole component 25 Inner side surface 25L, 25R Tool contact surface 26A, 26B Both end points 26C Intermediate point 27A, 27B Outer side surface

Claims (4)

  A bolt provided with a groove penetrating from the inner periphery to the outer periphery over the entire depth of the hole at each corner of a square hole having a regular polygonal inner periphery.   The intermediate point of each surface forming the square hole is positioned near the center of the hole with respect to a straight line connecting both end points of the surface, and a plane including each of both end points of each surface and the intermediate point is used as a tool contact surface. The bolt according to 1.   The bolt according to claim 1 or 2, wherein the outer periphery also forms a regular polygon.   A fork bolt for a front fork according to any one of claims 1 to 3.

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