JP2552693Y2 - Hump structure on bicycle rim - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a bicycle rim, and particularly to a hump structure provided on a bicycle rim to which a tubeless tire is mounted.

[Prior Art and Problems] When a tubeless tire is mounted on a bicycle rim, a protrusion called a hump is provided on the rim bead portion to prevent air leakage and is provided on the entire periphery of the rim to prevent air leakage and tire dropping. Was prevented from falling off.

However, the rim bead portion of the bicycle rim has a narrow width, and it is technically difficult to provide the above-described hump. Further, since the hump protrudes from the surface of the rim bead portion, there is a disadvantage that the workability of mounting the tubeless tire is poor.

[Technical problem] The present invention can easily provide a hump in a bicycle rim to which the above-mentioned tubeless tire is mounted,
It is another technical object of the present invention to provide a hump structure capable of easily mounting a tubeless tire and preventing a tire bead from falling off from a rim bead.

[Means for Solving the Problems] In a bicycle rim in which a hump groove 5 is provided around the entire circumference of a rim bead portion 2 on which a tire bead portion 3 is placed, a shape memory alloy which changes into a memory shape at a predetermined transformation point temperature. And an annular hump material 1 having a tip portion 1a protruding from a hump groove 5. The tip portion 1a of the hump material 1 is transformed when the tire 4 is mounted on a rim of a tire bead portion 3. Without being heated to the point temperature, it is bent inward of the rim cross section, and is heated to the transformation point temperature, whereby the tip 1a
Has a posture in which the tire bead portion 3 is sandwiched toward the rim flange portion 6 and is fixed to the hump groove 5.

[Operation] The hump structure of the present invention operates as follows.

With the hump material 1 bent toward the inside of the rim section,
The tire bead portion 3 of the tubeless tire is placed on the rim bead portion 2. After the tire is mounted, the hump material 1 is raised to the transformation temperature, so that the hump material 1 rises to the rising angle in the memorized state, and the tire bead portion 3 is sandwiched by the hump material 1, so that the rim bead portion 2 at a predetermined position.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

As shown in FIGS. 1 and 2, the rim 1 using the hump structure of the present invention includes a rim bead portion 2, a rim flange portion 6, and a drop portion 7, and a tire 4 mounted on the rim 1 is provided. Has a tire bead portion mounted on the rim bead portion.

Further, the rim bead portion 2 is provided with a hump groove all around the rim, and a hump material is mounted in this groove. It is better that the hump material does not protrude from the rim bead portion when the tire is mounted, and it is better that the hump material protrudes from the rim bead portion after the tire is mounted so as to serve as a hump. Use a shape memory alloy.

Next, the operation of the hump structure of the present invention will be described. First, a flat plate of a shape memory alloy as the hump material 1 is deformed as shown in FIGS. 8 (a) and 8 (b).

That is, the internal angle α is set to 100 degrees or more, and heating is performed to the transformation temperature in order to memorize this shape. Thereafter, the hump material 1 is bent inward to the inside of the rim cross section so that the internal angle α is 90 degrees or less, and as shown in FIG. The material is mounted in the hump groove 5. (FIG. 3) Next, a tubeless tire is mounted, and the tire bead portion in this state is in a state of being mounted on a hump material. (FIG. 4) Further, the hump material having an internal angle α of 90 degrees or less is heated to the transformation temperature, and the angle of the memorized state is returned to 100 degrees or more. Hump 1
At this time, the tire bead portion 3 is pressed to the rim flange portion side by the hump material, and is placed at a predetermined position of the rim bead portion. (FIG. 1) As means for joining the hump material cut into dimensions, a fifth type is used.
Means as shown in FIGS.

That is, as shown in FIG. 5, the concave portion 10 is formed by pressing the portion of the rim bead portion 2 located on the side surface of the joint portion 12 between the one end portion 8 and the other end portion 9 of the hump material 1 inserted into the hump groove 5. I do. As a result of the formation of the concave portion 10, the portion of the hump groove 5 where the joint portion 12 is located is squeezed. This results in a joint
12 is pressed and fixed at the narrowed portion of the hump groove 5.

In FIG. 6, the one end portion 8 and the other end portion 9 of the hump material are joined by a rivet 11 to the overlapping portion 15 where the hump material is overlapped.

FIG. 7 shows a case where the cross-sectional shape of the hump groove is formed inside the hump groove 14 having a larger width than the hump groove insertion opening 13 and a hump material is inserted therein.

That is, first, the hump material 1 is heated to the transformation temperature, and the shape matching the shape of the hump groove is stored in the hump material 1 as shown in FIG.

Next, the hump material having this shape stored is shown in FIG. 7 (b).
The hump material is deformed into a shape that can pass through the hump groove insertion opening 13 as described above, and the hump material is inserted into the hump groove.

Finally, when the hump material is heated in the hump groove, the hump material returns to a shape conforming to the shape of the hump groove as shown in FIG. That is,
Immediately after the hump material 1 is mounted on the rim of the tire bead portion 3, the tip 1a protruding from the hump groove 5 is bent inward of the rim section. After the mounting of the tire bead portion 3 to the rim is completed, the tip portion 1a of the hump material 1 is heated to the transformation point temperature, so that the tire bead portion 3 stands up so as to be clamped toward the rim flange portion 6. .

FIG. 9 shows a case in which the state before cutting the dimensions of the hump material is spiral.

[Effects of the Invention] The present invention has the above configuration, and thus has the following unique effects.

(A) Since the hump can be provided by mounting the hump material 1 in the hump groove 5, molding is facilitated.

(B) When the tire 4 is mounted, the hump material 1 is bent by the inner side of the rim section and does not stand up from the rim bead portion 2, so that the mounting is simplified. Then, since the hump material rises, the tire bead portion 2 is pushed by the flange portion 6 of the rim,
It is firmly fixed to the rim bead part 2.

(C) Since the rising length can be made longer than that of the conventional hump, the effect of preventing the tire from falling off is great.

[Brief description of the drawings]

FIG. 1 is a sectional view of an essential part of an embodiment of the present invention, FIG. 2 is a sectional view when a hump groove is provided, FIG. 3 is a sectional view when a hump material is inserted into the hump groove, and FIG. 5 and 6 are perspective views of an embodiment of the joining means for the hump material, FIG. 7 is a sectional view when the inside width of the hump groove is larger than the insertion opening, 7 (a), 7 (b) and 7 (c) are explanatory views of the operation, FIG. 8 (a) is an explanatory view of a hump material in a stored state, FIG. 8 (b) is an explanatory view of a hump material before mounting a tire, FIG. 9 is an explanatory view when the hump material is in a spiral state, 1: hump material, 1a: tip portion, 2: rim bead portion, 3: tire bead portion, 4: tire, 5: hump groove, 6: rim flange. Part 7, 7:
Drop part, 8: one end, 9: the other end, 10: recess, 11: rivet, 12: joint, 13: hump groove insertion port, 14: inside the hump groove, 15: overlapping part.

Claims (3)

(57) [Scope of request for utility model registration] 1. A bicycle rim in which a hump groove 5 is provided around the entire circumference of a rim bead portion 2 on which a tire bead portion 3 is placed, comprising a shape memory alloy which changes into a memory shape at a predetermined transformation point temperature. An annular hump material 1 having a tip portion 1a protruding from the groove 5 is provided. The tip portion 1a of the hump material 1 is heated to the transformation point temperature when the tire 4 is mounted on the rim of the tire bead portion 3. Without being bent, it is bent inward of the rim section, and by being heated to the transformation point temperature, the tip 1a is
A hump structure characterized in that the tire bead portion (3) is fixed to the hump groove (5) in a posture sandwiching the rim flange portion (6) toward the rim flange portion (6). 2. A joint between one end 8 and the other end 9 of the hump material 1.
Press the part of the rim bead part 2 located on the side of 12 and
A recess 10 is formed, and as a result of the formation of the recess 10,
The hump structure according to claim 1, wherein a portion of the hump groove where the twelve is located is squeezed, and the joint portion is fixed to a squeezed portion formed in the hump groove. 3. The hump structure according to claim 1, wherein the width of the inside of the hump groove is set to be larger than the width of the hump groove insertion opening.