JPH09290601A - Wheel for bicycle and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stabilize strength by uniforming wall thickness of a hollow spoke part by forming a plural number of through holes through which each cavity of the hollow spoke parts is communicated on a ring rim part and providing a cap to prevent bulging of a tube to each of the through holes on each of the through holes. SOLUTION: A plural number of hollow spoke parts 3 are extended outward from a hub part 2 axially supported on an axle of a bicycle, and a ring rim part 4 furnished with a sectionally roughly U shaped peripheral groove 11 is connected to each outer end of these hollow spoke parts 3 and it is integrally formed. Thereafter, a through hole 9 through which each cavity 8 of each of the spoke parts 3 is communicated is formed on the rim part 4, the through hole 9 and a through hole 12 of a peripheral groove bottom part 11A of the rim part 4 are made on the same level on an inner surface of the cavity 8 of the hollow spoke part 3 and in the diametrical direction of a wheel 1, and a cap 15 for tube support to prevent bulging of a tire tube is fit on the through hole 12 of the peripheral groove bottom part 11A of the rim part 4. Consequently, it is possible to uniform wall thickness of each of the hollow spoke parts 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bicycle wheel made of hard synthetic resin or light metal.

[0002]

2. Description of the Related Art A bicycle wheel of this type is connected to a hub portion pivotally supported by a bicycle axle, a plurality of spoke portions extending radially outward from the hub portion, and outer ends of the spoke portions. In addition, there is an annular rim portion into which a tire including a tube is fitted and which is injection-molded with a synthetic resin material.

Some conventional spokes are hollow so as to reduce their weight. The hollows are formed by blow molding, or the wheels are divided into left and right parts and the spokes are formed. A recess is formed in the portion, and later, the left and right are bonded to each other so that the recess is abutted to form a hollow inside of the spoke portion.

[0004]

By the way, among the above-mentioned conventional techniques, in the method of hollowing the spokes by blow molding, the wall thickness may not be uniform and the strength may be unstable. In the method of separately molding, there is a problem that the number of steps such as the step of adhering the left and right is increased and the manufacturing cost is increased.

The present invention has been made in view of the above situation, and an object thereof is to facilitate the integral molding of a wheel and to make the thickness of the spokes uniform to stabilize the strength. (EN) Provided are a bicycle wheel and a method for manufacturing the same, which are capable of achieving cost reduction.

[0006]

According to the present invention, the following technical measures have been taken in order to achieve the above object. That is, according to the present invention, a hub portion axially supported by a bicycle axle, a plurality of hollow spoke portions radially extending outward from the hub portion, and a tube that is connected to the outer ends of the spoke portions and includes a tube are included. A ring-shaped rim portion into which the tire is fitted is integrally molded, and a through hole is formed in the rim portion, the through holes communicating with the respective cavities of the hollow spoke portion, and the through hole is connected to the through hole of the tube. The feature is that a cap is provided in order to prevent the bulge. In this way, by making each cavity of the spoke part communicate with the through hole provided in the rim part, it becomes possible to integrally form by injection molding method using a core or casting method such as die casting, and the wall thickness of the hollow part Is uniform and molding is easy. Furthermore, by providing the cap in the through hole, the tube does not bulge from the through hole into the cavity, and it is possible to prevent the tube from being deformed or damaged (claim 1).

Further, the present invention is characterized in that the hub portion, the spoke portion and the rim portion are integrally molded by a hard synthetic resin, whereby the bicycle can be easily integrally molded by injection molding with good mass productivity. It is possible to obtain a bicycle wheel and a lightweight bicycle wheel (claim 2). Further, the present invention is characterized in that the hub portion, the spoke portion, and the rim portion are integrally molded with a light metal, whereby a bicycle wheel is cast, for example, cooling strain during molding when the wheel is molded by die casting. It is possible to obtain a well-balanced wheel, and it is possible to obtain a wheel that is lighter in weight while maintaining the necessary strength and making the wheel thinner. 3).

Further, the present invention is characterized in that each of the cavities of the spoke portion is formed in a taper shape whose cross-sectional area is gradually increased outward in the radial direction. The work of removing the core mold becomes easy (claim 4). Further, in the present invention, each cavity of the spoke portion and the through hole are formed in a modified elliptical shape having a major axis parallel to the circumferential direction of the rim portion, and the outer peripheral contour of the spoke portion is a streamline shape of a modified ellipse. Therefore, the air resistance accompanying the rotation of the wheel is reduced, the running resistance of the bicycle is reduced, and the bicycle can be driven lightly (claim 5).

The present invention is characterized in that the outer surface of the cap is flush with the inner surface of the rim portion.
The tube in the tire is securely prevented from being deformed or damaged (claim 6). Further, the present invention is characterized in that a reinforcing rib that fits into the through hole is provided on an inner surface of the cap, whereby the cap is not damaged by air pressure of the tube, and the through hole is surely provided. And the reinforcing rib facilitates positioning of the cap with respect to the through hole (claim 7).

The reinforcing ribs of the cap are vertical ribs fitted between both ends of the through hole in the circumferential direction of the rim,
It is characterized in that it comprises a lateral rib fitted between both ends in the axial direction, so that the positioning of the cap in the circumferential direction and the axial direction with respect to the through hole is ensured (claim 8). A wheel manufacturing method according to the present invention is a manufacturing method of integrally molding a bicycle wheel by mold molding,
The core mold that forms each cavity of the spoke part and the through hole, the radially inner end side is supported by a molding die between the molding spaces of the inner cylinder body and the outer cylinder body that form the hub portion, It is characterized in that the radially outer end side is supported by a split mold forming a rim portion.

In this case, both ends of the core forming the respective cavities of the spoke portion are surely positioned and supported by the molding die, so that the wall thickness becomes uniform. After molding, the core can be pulled out radially outwardly prior to or at the same time as the separation of the split molds to separate the molds, which makes the manufacturing extremely simple (claim 9).

[0012]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 16 show a first embodiment of a bicycle wheel 1 according to the present invention. The wheel 1 includes a hub portion 2 that is axially supported by a bicycle axle (not shown), a plurality of hollow spoke portions 3 (five in this example) that extend radially outward from the hub portion 2, and It comprises an annular rim portion 4 connected to each outer end of the spoke portion 3.

The hub portion 2, the hollow spoke portion 3 and the rim portion 4 are injection molded by using a hard synthetic resin containing a reinforcing material such as glass fiber, carbon fiber and reinforcing powder, for example, glass fiber containing nylon resin. Alternatively, they are integrally formed by a casting method such as die casting using a light metal such as magnesium, aluminum, titanium, or an alloy thereof.

When mass production is carried out by a die casting method using a light metal as a magnesium alloy, (Mg) 9
0.4 wt%, (Al) 8.7 wt%, (Zn) 0.7
It is preferable to use a die casting alloy having a weight percentage of (Mn) of 0.2 wt%. The hub portion 2 has an inner cylindrical body 5 that is fitted onto the axle, an outer cylindrical body 6 that concentrically surrounds the inner cylindrical body 5 and connects the spokes 3, and inner and outer cylinders 5, 5. It is composed of a plurality of (five in this example) connecting bodies 7 arranged radially between the two tubular bodies 5, 6 so as to connect the six in the radial direction. When the wheel 1 is molded from synthetic resin, a hub shaft (not shown) serving as a mounting portion on the bicycle side is insert-molded inside the inner tubular body 5.

The spoke portion 3 has a wheel rotation direction R.
So that a part of the front end edge 3A of the same matches the tangent line of the outer cylindrical body 6 of the hub portion 2 and the rear end edge 3B of the wheel rotation direction R matches the straight line passing through the center of the hub portion 2. The cross-sectional area inside each cavity 8 (the area of the cross section orthogonal to the radial direction of the spoke portion 3) extending from the outer cylindrical body 6 is gradually increased outward in the radial direction (radial direction). There is. The end of each cavity 8 on the center side of the wheel 1 communicates with a through hole 9 formed in the outer cylindrical body 6 of the hub portion 2 between the connecting bodies 7 and radially extending therethrough (Fig. 2, FIG. 4 and FIG. 5).

The cross-sectional shape of the spoke portion 3 is
As shown in FIGS. 6 to 8, the axial dimension is smaller than the circumferential dimension (the major axis is parallel to the circumferential direction) and has a modified elliptical shape, and the outer peripheral contour is tapered on the leading side in the wheel rotation direction R. It has a streamlined shape and is designed to reduce air resistance when the wheel 1 rotates. And
Ribs 1 are provided on both sides in the axial direction of the hub 2 side base of the spokes 3.
0 is provided respectively.

As shown in FIGS. 2 and 9, the rim portion 4 is provided with a peripheral groove 11 having a substantially U-shaped cross section, and the outer peripheral portion of the peripheral groove bottom portion 11A is outside the spoke portions 3. The ends are connected and integrated, and a tire (not shown) is fitted between the flanges 11B on both sides in the axial direction, and a tire tube (also not shown) is included in the tire. There is.

The peripheral groove bottom portion 11A of the rim portion 4 is
A through hole 12 that communicates with the cavity 8 of each spoke portion 3 is provided. The through hole 12 and the through hole 9 of the hub portion 2
Is a taper surface that is flush with the inner surface of the cavity 8 of the spoke portion 3 in the radial direction of the wheel 1, and the cavity-forming core (described later) during molding of the wheel 1 can be easily outward in the radial direction. It can be pulled out.

Further, on the inner surface of the peripheral groove bottom portion 11A of the rim portion 4, as shown in FIG. 3, modified elliptical concave portions 13 for cap fitting are formed on the outer peripheral side of the through holes 12, respectively. The cap locking holes 14 are provided on both sides of the through hole 12 in the circumferential direction of the rim portion 4 (see FIGS. 3, 10, and 11). A tube supporting cap 15 for preventing a tire tube (not shown) from bulging into the through hole 12 after the wheel 1 is molded is fitted into the recess 13.

The cap 15 has the shape shown in FIGS. 12 to 16 and is made of the same material as the wheel 1 (hard synthetic resin, light metal, etc.), and its planar shape is a modified elliptical shape having the same shape as the recess 13. The outer surface is a concave curved surface 15A that is flush with the inner surface of the circumferential groove bottom portion 11A. On the inner side surface 15B (center side of the wheel 1) of the cap 15, locking projections 16 that fit into the cap locking holes 14 are provided at both ends in the longitudinal direction, respectively. Substantially cruciform ribs 17 are provided so as to project in the longitudinal direction of the cap 15 and the direction orthogonal thereto.

The ribs 17 are composed of vertical ribs 17A which are parallel to the circumferential direction of the wheel, and horizontal ribs 17B which are parallel to the axial direction. The outer ends of the vertical and horizontal ribs 17A and 17B respectively have the circumferential groove bottom 11A. The inner surface of both end portions of the through hole 12 in the circumferential direction and the inner surface of both end portions in the axial direction are brought into contact with each other to exert the positioning function of the cap 15, and the pressure of the air enclosed in the tube is adjusted by the ribs 17A and B. It is configured to be transmitted to the circumferential groove bottom portion 11A via the circumferential surface, and has sufficient strength to support the air pressure in the tube.

Molding of the wheel 1 of the first embodiment is as follows.
This is performed by the manufacturing method according to the present invention. FIG. 17 shows a half of a cross section of a molding die for injection molding or casting adopted in the implementation of the manufacturing method according to the present invention. The die 18 includes an upper die 19, a lower die 20, and the rim portion. No. 4 flange 11B outer peripheral end and a plurality of circumferentially divided molds 21 that form the circumferential groove 11, and a plurality of cores that form the cavity 8 of the spoke portion 3 and the through holes 9 and 12 in a communicating manner. And the mold 22.

Each core die 22 has a die space side end 22A (inner end in the wheel radial direction) forming the hub portion 2.
Between the inner and outer cylindrical bodies 5 and 6 forming spaces 23 and 24 forming the hub portion 2 of the upper and lower molds 19 and 20, that is, the arc-shaped projection 2
5, 26 supported by the wheel radial outer end 22B
However, the taper that penetrates the space 27 forming the rim portion 4 and is supported by each of the split molds 21 has a cross-sectional area that gradually increases from the wheel radial inner end 22A to the outer end 22B. Has been granted.

When the molding material is flowed into the molding space (cavity) of the mold 1, that is, the reinforcing material-containing nylon or the like is injection-injected or the magnesium alloy or the like is press-fitted, and when the cooling and solidification of the molding material is completed, The wheel 1 is integrated by pulling out the core mold 22 to the outside in the radial direction of the wheel 1, separating each split mold 21 to the outside in the radial direction, and then separating and opening the upper and lower molds 19 and 20. The hollow portion 8 of the hollow spoke portion 3 and the through holes 9 and 12 are formed to communicate with each other, and the thickness of the spoke portion 3 becomes uniform.

According to the method of the present invention, the core mold 22 is accurately positioned and supported by the upper and lower molds 19 and 20 and the split mold 21, so that when the molding material flows into the mold cavity, Since the mold 22 does not move due to the flow of the molding material, the wall thickness of the hollow spoke portions 3 becomes uniform as designed, and the good quality wheel 1 can be integrally molded by injection molding.

When the wheel 1 is made of light metal, dimensional distortion due to cooling or the like is less likely to occur during molding after casting, as compared with the case where it is made of hard synthetic resin, and warpage and load are prevented. Since it is possible to form a wheel without imbalance and has the advantage that it is possible to reduce the thickness while maintaining the required strength, it is possible to further reduce the weight. .

In the above embodiment of the method of the present invention, the number of divisions of the division die 21 of the forming die 18 is set to the core die 22.
By setting the number to be the same, the split molds 21 and the core mold 22 can be removed at the same time. 18 to 21
Shows a second embodiment of the bicycle wheel 1 according to the present invention. The difference from the first embodiment is that the center of the spoke portion 3 is radially aligned with the straight line passing through the axial center of the hub portion 2. The cross section of the spoke portion 3 is a true ellipse, and the cap 15 has no rib and bulges outward in the radial direction of the wheel 1, which is equivalent to that of the first embodiment. It is possible to expect an effect. Therefore, the reference numerals of FIGS. 18 to 21 are given the same reference numerals as those of FIGS. 1 to 16, and detailed description thereof will be omitted.

Incidentally, the cap 15 in the second embodiment.
Is designed to be deformed by the air pressure of the tire tube fitted to the rim portion 4 so as to be flush with the inner surface of the circumferential groove bottom portion 11A, and to maintain the proper shape of the tire tube. Reference numeral 28 in FIG. 18 denotes an air valve mounting hole.
The wheel 1 of the second embodiment is also integrally formed by the method of the present invention as in the first embodiment.

The present invention is not limited to the above-mentioned embodiment, but the design can be changed as appropriate.

[0030]

As described above, the bicycle wheel according to the present invention has a hub portion axially supported by a bicycle axle, a plurality of hollow spoke portions extending radially outward from the hub portion, and An annular rim that is connected to the outer ends of the spokes and into which a tire containing a tube is fitted is integrally formed, and a through hole that communicates with each cavity of the hollow spokes is formed in the rim. Since a cap is provided in the through hole to prevent the tube from bulging into the through hole, it is possible to integrally form hollow spokes with a uniform wall thickness by injection molding or casting, and the strength is stable. However, it is possible to improve the quality and reduce the manufacturing cost. Furthermore, by providing the cap in the through hole, the tube does not bulge from the through hole into the cavity, and it is possible to prevent the tube from being deformed or damaged (claim 1).

According to the second aspect of the present invention,
Since the hub portion, the spoke portion, and the rim portion are integrally formed of hard synthetic resin, it is possible to obtain a bicycle wheel which is easily integrally formed by injection molding and has good mass productivity, and a lightweight bicycle wheel. According to the invention as set forth in claim 3, since the hub portion, the spoke portion and the rim portion are integrally molded with a light metal, there is little cooling strain during molding when the wheel is molded by casting such as die casting. Therefore, it is possible to obtain a well-balanced wheel, and it is also possible to obtain a wheel that is lighter in weight, while maintaining the necessary strength and making the wheel thinner.

Further, according to the invention as set forth in claim 4, since each cavity and the through hole of the spoke portion are formed in a taper shape whose cross-sectional area is gradually increased outward in the radial direction, This facilitates the work of detaching the core mold during molding. Further, according to the invention of claim 5, each cavity of the spoke portion and the through hole are formed in a modified elliptical shape having a major axis parallel to the circumferential direction of the rim portion, and the outer peripheral contour of the spoke portion is Since it is a streamlined shape of a deformed ellipse, air resistance due to wheel rotation decreases,
The running resistance of the bicycle is reduced and you can drive lightly.

Further, according to the invention of claim 6,
Since the outer surface of the cap is flush with the inner surface of the rim portion, deformation and damage of the tube inside the tire are reliably prevented. Further, according to the invention as set forth in claim 7, since the reinforcing rib fitted into the through hole is provided on the inner surface of the cap, the cap is not damaged by the air pressure of the tube. The through hole can be surely closed, and the reinforcing rib facilitates the positioning of the cap with respect to the through hole.

According to the invention described in claim 8,
Since the reinforcing ribs of the cap are composed of vertical ribs fitted between both ends of the through hole in the circumferential direction of the rim and lateral ribs fitted between both ends of the axial direction, the circumferential direction and the axial direction with respect to the through hole. Positioning of the cap with respect to is assured. The wheel manufacturing method according to the present invention is a manufacturing method in which a bicycle wheel is integrally molded by molding, and the core mold for forming each cavity of the spoke portion and the through hole is
The radially inner end side is supported by a molding die between the inner cylinder body and the outer cylinder body forming the hub portion, and the radially outer end side is supported by a split die forming a rim portion. Therefore, the thickness of the spoke portion is uniform, and it is possible to improve the quality and significantly reduce the manufacturing cost (claim 9).

[Brief description of drawings]

FIG. 1 is a front view showing a first embodiment of a wheel of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is an enlarged view taken along the arrow B of FIG.

FIG. 4 is an enlarged front view of the hub portion of the same embodiment.

FIG. 5 is a sectional view taken along line CC of FIG. 4;

6 is an enlarged cross-sectional view taken along the line DD of FIG.

7 is an enlarged cross-sectional view taken along the line EE of FIG.

FIG. 8 is an enlarged cross-sectional view taken along line FF of FIG.

9 is an enlarged cross-sectional view taken along the line GG of FIG.

10 is a cross-sectional view taken along the line HH of FIG.

FIG. 11 is a sectional view taken along line II of FIG. 10;

FIG. 12 is a plan view of the cap according to the first embodiment.

FIG. 13 is a front view of FIG.

FIG. 14 is a rear view of FIG.

FIG. 15 is a right side view of FIG.

16 is a sectional view taken along line JJ of FIG.

FIG. 17 is a partial sectional view of a molding die used for carrying out the method of the present invention.

FIG. 18 is a partially cutaway front view showing a second embodiment of the wheel of the present invention.

FIG. 19 is a sectional view taken along line LL of FIG. 18;

20 is an enlarged view of portion K in FIG.

FIG. 21 is a sectional view taken along line MM of FIG. 19;

[Explanation of symbols]

 1 Bicycle Wheel 2 Hub Part 3 Spoke Part 4 Rim Part 5 Inner Cylinder 6 Outer Cylinder 7 Coupling 8 Cavity 9 Through Hole 12 Through Hole 15 Cap 17 Rib 18 Molding Die 19 Upper Die 20 Lower Die 21 Split Die 22 Core type 22A Core inner end side 22B Core outer end side 23 Inner cylinder forming space 24 Outer cylinder forming space

Claims (9)

[Claims] 1. A hub portion axially supported by a bicycle axle, a plurality of hollow spoke portions radially extending outward from the hub portion, and a tube which is connected to the outer ends of the spoke portions and includes a tube. An annular rim portion into which a tire is fitted is integrally formed, and a through hole is formed in the rim portion, in which each cavity of the hollow spoke portion communicates, and the through hole,
A bicycle wheel, wherein a cap is provided to prevent the tube from bulging into the through hole. 2. The bicycle wheel according to claim 1, wherein the hub portion, the spoke portion, and the rim portion are integrally formed of hard synthetic resin. 3. The bicycle wheel according to claim 1, wherein the hub portion, the spoke portion, and the rim portion are integrally formed of light metal. 4. The spokes according to claim 1, wherein each of the cavities of the spoke portion is formed in a taper shape in which a cross-sectional area thereof gradually increases outward in a radial direction. Bicycle wheel. 5. The cavities of the spoke portion and the through hole are formed in a modified elliptical shape having a major axis parallel to the circumferential direction of the rim portion, and the outer peripheral contour of the spoke portion is streamlined. The bicycle wheel according to any one of claims 1 to 4, characterized in that: 6. The bicycle wheel according to claim 1, wherein an outer surface of the cap is flush with an inner surface of the rim portion. 7. The bicycle wheel according to claim 1, wherein a reinforcing rib that fits into the through hole is provided on an inner surface of the cap. 8. The reinforcing rib of the cap comprises a vertical rib fitted between both ends of the through hole in the circumferential direction of the rim portion, and a horizontal rib fitted between both ends of the through hole in the axial direction. The bicycle wheel according to claim 7. 9. The manufacturing method for integrally molding the bicycle wheel according to claim 1 by molding, wherein a core mold for forming each cavity of the spoke portion and the through hole has a radially inner end thereof. The side is supported by a molding die between the molding spaces of the inner cylinder and the outer cylinder forming the hub portion, and the radial outer end side is supported by a split mold forming a rim portion. Method for manufacturing bicycle wheel.