A bicycle inner tube mold

Abstract

This utility model provides a bicycle inner tube mold for forming a bicycle inner tube, including an inner cavity for receiving a green tire. A valve stem is disposed on the inner side of the green tire, and the valve stem includes a valve stem body and an air cushion. The inner cavity includes an inner ring wall and an outer ring wall, and includes a valve stem forming section. An insertion hole is provided on the inner ring wall of the valve stem forming section for receiving the valve stem body. The radial dimension of the outer ring wall of the valve stem forming section gradually decreases from its two sides towards the center, with the center of the outer ring wall corresponding to the insertion hole. Applying this technical solution can provide a bicycle inner tube mold that improves poor edge cracking of the valve stem.

Description

Technical Field

[0001] This utility model relates to equipment for forming bicycle tires, specifically a bicycle inner tube mold. Background Technology

[0002] During the manufacturing process of bicycle inner tubes, a specific defect known as "valve edge cracking" exists. This problem manifests as cracking at the edge of the area where the inner tube valve meets the tire carcass rubber. Its root cause is closely related to the inner tube molding process. For details, please refer to... Figure 1 During the molding stage of the green tire 30 (the uncured inner tube semi-finished product), when the green tire 30 is inflated and shaped by gas, the tire body changes from a flat shape to a ring shape. This morphological change causes significant stress concentration in the edge area of ​​the air cushion 20 (or gasket, valve base) that is originally attached to the valve stem 10 of the green tire. Under this stress, the edge of the air cushion 20 is prone to developing tiny cracks 40. Once such micro-cracks appear, during subsequent processing or storage, contaminants such as dust, oil, moisture, or mold release agents in the environment may penetrate the crack and directly contact the bonding interface between the valve stem and the tire body rubber, resulting in cracking at the valve stem edge and forming a "valve edge crack" defect. This problem directly affects the airtightness and service life of the inner tube and is a key technical challenge that needs to be carefully controlled during the manufacturing process. Utility Model Content

[0003] The purpose of this invention is to overcome the shortcomings of the prior art and provide a bicycle inner tube mold that can improve the poor edge cracking of the nozzle.

[0004] To solve the above-mentioned technical problems, this utility model provides a bicycle inner tube mold for forming a bicycle inner tube, including an inner cavity for receiving a green tire, wherein a valve stem is provided on the inner side of the green tire, and the valve stem includes a valve stem body and an air cushion.

[0005] The inner cavity includes an inner ring wall and an outer ring wall. The inner cavity includes a valve stem forming section. The inner ring wall of the valve stem forming section is provided with an insertion hole for receiving the valve stem body. The radial dimension of the outer ring wall of the valve stem forming section gradually decreases from its two sides to the middle position. The middle position of the outer ring wall of the valve stem forming section corresponds to the insertion hole.

[0006] In some embodiments, the inner cavity further includes a main body forming section, wherein the curvature of the outer ring wall of the main body forming section is greater than the curvature of the outer ring wall of the valve stem forming section.

[0007] In some embodiments, the outer ring wall of the valve stem forming section extends in a smooth curve.

[0008] In some embodiments, an upper mold base and a lower mold base are included, the upper surface of the lower mold base includes a first mold cavity, and the lower surface of the upper mold base includes a second mold cavity. The upper mold base and the lower mold base can be opened and closed vertically to form the inner cavity by the first mold cavity and the second mold cavity.

[0009] In some embodiments, the lower mold base includes a first half-groove connecting the first mold cavity, and the upper mold base includes a second half-groove connecting the second mold cavity, wherein the first half-groove and the second half-groove can be connected to define the insertion hole.

[0010] Compared with the prior art, the technical solution of this utility model has the following beneficial effects:

[0011] During the inflation and shaping process, the green tire expands. Since the radial dimension of the outer ring wall of the valve stem forming section gradually decreases from its sides towards the center, and the center of the outer ring wall corresponds to the insertion hole, the green tire is compressed by the inner and outer ring walls of the valve stem forming section. This results in an overall elliptical cross-section of the green tire, ensuring the air cushion of the valve stem adheres tightly to the green tire. This prevents the edges of the air cushion from opening up, thereby reducing poor edge adhesion. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the forming process of a green mold and a die in the background art;

[0013] Figure 2 This is a schematic diagram of the inner cavity of the bicycle inner tube mold of this utility model;

[0014] Figure 3 This is a schematic diagram of the lower mold base and the green mold of this utility model. Detailed Implementation

[0015] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0016] See Figure 2-3 A bicycle inner tube mold for forming a bicycle inner tube, the bicycle inner tube mold including an inner cavity 1 for receiving a green tire 2, the inner side of which is provided with a valve stem, the valve stem including a valve stem body 211 and an air cushion 212.

[0017] The inner cavity 1 includes an inner ring wall 11 and an outer ring wall 12. The inner cavity 1 includes a valve stem forming section 13. The inner ring wall 11 of the valve stem forming section 13 is provided with an insertion hole 131 for receiving the valve stem body. The radial dimension of the outer ring wall 12 of the valve stem forming section 13 gradually decreases from its two sides to the middle position. The middle position of the outer ring wall 12 of the valve stem forming section 13 corresponds to the insertion hole 131.

[0018] During the molding process, the green tire 2 is first placed in the inner cavity 1, and the valve body 211 of the green tire 2 is inserted into the corresponding insertion hole 131. Subsequently, during the inflation and shaping process, the green tire 2 inflates and expands. Since the radial dimension of the outer ring wall 12 of the valve forming section 13 gradually decreases from its two sides to the middle position, and the middle position of the outer ring wall 12 of the valve forming section 13 corresponds to the insertion hole 131, the green tire 2 is compressed by the inner ring wall 11 and the outer ring wall 12 of the valve forming section 13, making the overall cross-section of the green tire 2 elliptical. This ensures that the air cushion 212 of the valve is tightly attached to the green tire 2, thereby preventing the edges of the air cushion 212 from opening and reducing poor edge cracking of the valve.

[0019] In this embodiment, the inner cavity 1 further includes a main body forming section 14, which is used to form the remaining part of the green tire 2. The curvature of the outer ring wall 12 of the main body forming section 14 is greater than the curvature of the outer ring wall 12 of the valve stem forming section 13, so that the outer ring wall 12 of the valve stem forming section 13 is closer to the inner ring wall 11 than other parts, and the outer ring wall 12 of the valve stem forming section 13 is arc-shaped, more specifically, it is an arc corresponding to the major axis of an ellipse, so that the outer ring wall 12 of the valve stem forming section 13 extends in a smooth curve.

[0020] The bicycle inner tube mold includes an upper mold base and a lower mold base 3. The upper surface of the lower mold base 3 includes a first mold cavity 31, and the lower surface of the upper mold base includes a second mold cavity. The upper and lower mold bases 3 can open and close vertically to form the inner cavity 1 by the first mold cavity 31 and the second mold cavity. The lower mold base 3 includes a first half-groove 32 connecting the first mold cavity 31, and the upper mold base includes a second half-groove connecting the second mold cavity. The first half-groove 32 and the second half-groove can connect to define the insertion hole 131. During the molding process, the upper and lower mold bases 3 are opened and closed first, then the green tire 2 is placed on the first mold cavity 31, so that the valve stem body 211 is placed on the first half-groove 32. Then the upper mold base is closed, and then inflation molding is performed.

[0021] The above description is only a preferred embodiment of the present utility model, but the design concept of the present utility model is not limited thereto. Any non-substantial modifications made to the present utility model by those skilled in the art within the scope of the technology disclosed in the present utility model using this concept shall be deemed as an infringement of the protection scope of the present utility model.

Claims

1. A bicycle inner tube mold for forming a bicycle inner tube, characterized in that, It includes an inner cavity for receiving a live fetus, the inner side of which is provided with a valve stem, the valve stem including a valve stem body and an air cushion; The inner cavity includes an inner ring wall and an outer ring wall. The inner cavity includes a valve stem forming section. The inner ring wall of the valve stem forming section is provided with an insertion hole for receiving the valve stem body. The radial dimension of the outer ring wall of the valve stem forming section gradually decreases from its two sides to the middle position. The middle position of the outer ring wall of the valve stem forming section corresponds to the insertion hole.

2. The bicycle inner tube mold as described in claim 1, characterized in that: The inner cavity also includes a main body forming section, the curvature of the outer ring wall of the main body forming section being greater than the curvature of the outer ring wall of the valve stem forming section.

3. A bicycle inner tube mold as described in claim 2, characterized in that: The outer ring wall of the valve stem forming section extends in a smooth curve.

4. A bicycle inner tube mold as described in claim 3, characterized in that: It includes an upper mold base and a lower mold base. The upper surface of the lower mold base includes a first mold cavity, and the lower surface of the upper mold base includes a second mold cavity. The upper mold base and the lower mold base can be opened and closed vertically to form the inner cavity with the first mold cavity and the second mold cavity.

5. A bicycle inner tube mold as described in claim 4, characterized in that: The lower mold base includes a first half-groove connecting the first mold cavity, and the upper mold base includes a second half-groove connecting the second mold cavity. The first half-groove and the second half-groove can be connected to define the insertion hole.

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