Polyurethane pneumatic-free tire centrifugal mold

Abstract

The utility model discloses a kind of polyurethane inflating-free tire centrifugal mould, including lower mould and upper mould, the upper surface of lower mould is provided with first annular groove, the lower surface of upper mould is provided with the second annular groove corresponding with first annular groove, a mould cavity is enclosed between first annular groove and second annular groove, the middle part of upper mould is provided with injection hole, the lower surface of upper mould has the transition surface between injection hole and second annular groove, transition surface and lower mould form feeding gap, upper mould and lower mould are also provided with the burr gap that is around the outside of mould cavity and is communicated with mould cavity. Burr can be formed in feeding gap and burr gap, by setting the width of the two gaps, the thickness of burr can be controlled, so that burr can be in straight state, convenient to remove burr.

Description

Technical Field

[0001] This utility model relates to the field of production technology of airless tires, and in particular to a centrifugal mold for polyurethane airless tires. Background Technology

[0002] Traditional electric wheelchairs use tires consisting of a rubber outer tire and a rubber inner tire. Before use, the inner tire needs to be filled with air from the valve stem, which can lead to problems such as tire blowouts, punctures, and leaks at the valve stem.

[0003] To address these issues, some airless tires made of polyurethane foam and foam molds used to make these tires have appeared on the market. These foam molds generally include an upper mold and a lower mold, with a cavity between them. After the polyurethane tire is formed, burrs will form at the parting surface between the upper and lower molds. These burrs are thin and soft, and are difficult to remove with a blade. Utility Model Content

[0004] Therefore, the purpose of this utility model is to provide a polyurethane centrifugal mold for tires that is easy to remove burrs from.

[0005] The technical solution adopted by this utility model to solve its technical problem is as follows:

[0006] A centrifugal mold for a polyurethane pneumatic tire includes a lower mold and an upper mold. The upper surface of the lower mold is provided with a first annular groove, and the lower surface of the upper mold is provided with a second annular groove corresponding to the first annular groove. The first annular groove and the second annular groove form a mold cavity. An injection hole is provided in the middle of the upper mold. The lower surface of the upper mold has a transition surface located between the injection hole and the second annular groove. A feeding gap is formed between the transition surface and the lower mold. A rough edge gap is also provided between the upper mold and the lower mold, surrounding the outside of the mold cavity and communicating with the mold cavity.

[0007] In a preferred embodiment of this utility model, the width of the rough edge gap is smaller than the width of the feed gap, and the width of the rough edge gap is 0.1 to 0.8 mm.

[0008] In a preferred embodiment of the present invention, the edge of the upper surface of the lower mold is provided with an upwardly protruding first annular platform, the inner side of the first annular platform being a conical surface, and the lower surface of the upper mold is provided with a second annular platform surrounding the second annular groove, the outer side of the second annular platform having a conical surface that mates with the inner side of the first annular platform.

[0009] In a preferred embodiment of the present invention, the upper surface of the lower mold has a reference surface located between the first annular platform and the first annular groove, the lower surface of the second annular platform is in contact with the reference surface, a countersunk platform is provided between the reference surface and the first annular platform, and the upper surface of the countersunk platform and the lower surface of the second annular platform form the rough edge gap.

[0010] In a preferred embodiment of this utility model, the injection hole is a conical hole that gradually expands from top to bottom, or the injection hole is an inverted funnel-shaped hole.

[0011] In a preferred embodiment of this utility model, the upper or lower mold is provided with an exhaust hole that communicates with the rough edge gap.

[0012] In a preferred embodiment of this utility model, the vent hole is a stepped hole provided on the upper mold, which is larger at the top and smaller at the bottom, and the lower end of the stepped hole is connected to the rough edge gap.

[0013] The beneficial effects of this utility model are: the foamed material in the mold cavity will form the tire matrix, and the foamed material in the feed gap and the burr gap will form burrs. By setting the width of these two gaps, the thickness of the burrs can be controlled, so that the burrs can be in a straight state, making it easy to remove the burrs. Attached Figure Description

[0014] Figure 1 This is a cross-sectional view of Embodiment 1 of this utility model;

[0015] Figure 2 yes Figure 1 Enlarged view of section A;

[0016] Figure 3 This is an exploded view of Embodiment 1 of this utility model;

[0017] Figure 4 This is a cross-sectional view of Embodiment 2 of this utility model;

[0018] Figure 5 yes Figure 4 Enlarged view of section B. Detailed Implementation

[0019] The technical solution of this utility model will now be clearly and completely described with reference to the accompanying drawings.

[0020] It should be noted that all directional indicators (such as up, down, left, right, front, back, etc.) in this utility model are only used to explain the relative positional relationship and movement of the components in a specific posture (as shown in the attached figure). If the specific posture changes, the directional indicator will also change accordingly. Furthermore, descriptions involving "preferred," "second-preferred," etc., in this utility model are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "preferred" or "second-preferred" may explicitly or implicitly include at least one of those features.

[0021] Reference Figures 1 to 5 This utility model proposes a polyurethane pneumatic tire centrifugal mold, including a lower mold 1 and an upper mold 2. The upper surface of the lower mold 1 is provided with a first annular groove 11, and the lower surface of the upper mold 2 is provided with a second annular groove 21 corresponding to the first annular groove 11. The first annular groove 11 and the second annular groove 21 form a mold cavity 3. The middle part of the upper mold 2 is provided with an injection hole 22. The lower surface of the upper mold 2 has a transition surface 201 located between the injection hole 22 and the second annular groove 21. A feeding gap 4 is formed between the transition surface 201 and the lower mold 1. A rough edge gap 5 is also provided between the upper mold 2 and the lower mold 1, which surrounds the outside of the mold cavity 3 and communicates with the mold cavity 3.

[0022] Preferably, the width of the rough edge gap 5 is smaller than the width of the feed gap 4. The width of the rough edge gap 5 is 0.1 to 0.8 mm, such as 0.15 mm, 0.3 mm, 0.5 mm, 0.7 mm, etc., and the width of the feed gap 4 is 0.8 to 3 mm, such as 0.8 mm, 1.3 mm, 2 mm, 2.5 mm, etc.

[0023] Injection hole 22 is generally a round hole used for pouring polyurethane foam material. When using this mold, the lower mold 1 is typically fixed to a turntable using bolts or other fasteners. A motor drives the centrifugal mold to rotate. The centrifugal force of the rotation throws the polyurethane foam material injected from injection hole 22 into mold cavity 3, feed gap 4, and burr gap 5. After heating, the foam material in mold cavity 3 forms the tire matrix, while the foam material in feed gap 4 and burr gap 5 forms burrs. By setting the width of these two gaps, the thickness of the burrs can be controlled, ensuring the burrs remain straight and easy to remove. Furthermore, the burr gap 5 also serves as a venting mechanism. When the polyurethane foam material enters mold cavity 3, most of the air in mold cavity 3 is discharged through feed gap 4. When mold cavity 3 is almost full of polyurethane foam material, feed gap 4 may be blocked, allowing the remaining small amount of gas to be squeezed into burr gap 5. Without a sealing structure between the upper mold 2 and the lower mold 1, the material can eventually be discharged from the tiny gap between the upper mold 2 and the lower mold 1.

[0024] After the tire substrate in the mold cavity 3 has been heated and cured, the upper mold 2 can be opened and the tire substrate can be removed. To prevent the upper mold 2 from separating from the lower mold after it is opened, the upper mold 2 and the lower mold 1 can be connected on one side by a hinge, while the upper mold 2 and the lower mold 1 can be locked on the other side by a pin, screw or fastener assembly.

[0025] Example 1

[0026] Reference Figures 1 to 3 In this embodiment, the upper surface of the lower mold 1 has an upwardly protruding first annular platform 12 at its edge. The inner surface of the first annular platform 12 is a conical surface. The lower surface of the upper mold 2 has a second annular platform 23 surrounding the second annular groove 21. The outer surface of the second annular platform 23 has a conical surface that mates with the inner surface of the first annular platform 12. The upper surface of the lower mold 1 has a reference surface 13 located between the first annular platform 12 and the first annular groove 11. The lower surface of the second annular platform 23 is in contact with the reference surface 13. A countersunk platform 14 is provided between the reference surface 13 and the first annular platform 12. The upper surface of the countersunk platform 14 and the lower surface of the second annular platform 23 form a rough edge gap 5.

[0027] The injection hole 22 is a conical hole that gradually expands from top to bottom, or the injection hole 22 is an inverted funnel shape. The inverted funnel shape is the best, because with this design, the liquid polyurethane foam material can easily enter the mold cavity 3 through the feed gap 4 when the mold rotates.

[0028] Example 2

[0029] Figures 4 to 5 Embodiment 2 of this utility model is disclosed. This embodiment has a similar structure to Embodiment 1, the only difference being that an exhaust hole 6 communicating with the rough edge gap 5 is added in this embodiment. The exhaust hole 6 can be set in the upper mold 2 or the lower mold 1. The design of the exhaust hole 6 can improve the exhaust efficiency and make the exhaust smoother.

[0030] Preferably, the vent 6 is a stepped hole located on the upper mold 2, wider at the top and narrower at the bottom, with the lower end of the stepped hole communicating with the rough edge gap 5. This design results in a larger outlet end of the vent 6, which further improves venting efficiency. In addition, the section connecting the stepped hole to the rough edge gap 5 is the smaller end, which effectively prevents polyurethane foam material from flowing out along the vent 6.

[0031] The above are merely preferred embodiments of this utility model and do not limit the patent scope of this utility model. Any equivalent structural transformations made based on the inventive concept of this utility model and the contents of this utility model specification and drawings, or direct or indirect applications in other related technical fields, are included within the patent protection scope of this utility model.

Claims

1. A polyurethane pneumatic tire centrifugal mold, characterized in that, The mold includes a lower mold (1) and an upper mold (2). The upper surface of the lower mold (1) is provided with a first annular groove (11), and the lower surface of the upper mold (2) is provided with a second annular groove (21) corresponding to the first annular groove (11). The first annular groove (11) and the second annular groove (21) form a mold cavity (3). The upper mold (2) is provided with an injection hole (22) in the middle. The lower surface of the upper mold (2) has a transition surface (201) located between the injection hole (22) and the second annular groove (21). A feeding gap (4) is formed between the transition surface (201) and the lower mold (1). A rough edge gap (5) is also provided between the upper mold (2) and the lower mold (1) and surrounds the outside of the mold cavity (3) and communicates with the mold cavity (3).

2. The polyurethane pneumatic tire centrifugal mold according to claim 1, characterized in that, The width of the rough edge gap (5) is smaller than the width of the feed gap (4), and the width of the rough edge gap (5) is 0.1 to 0.8 mm.

3. The polyurethane pneumatic tire centrifugal mold according to claim 1, characterized in that, The upper surface of the lower mold (1) is provided with an upwardly protruding first annular platform (12), the inner side of the first annular platform (12) is a conical surface, and the lower surface of the upper mold (2) is provided with a second annular platform (23) surrounding the second annular groove (21), the outer side of the second annular platform (23) has a conical surface that mates with the inner side of the first annular platform (12).

4. The polyurethane pneumatic tire centrifugal mold according to claim 3, characterized in that, The upper surface of the lower mold (1) has a reference surface (13) located between the first annular platform (12) and the first annular groove (11). The lower surface of the second annular platform (23) is in contact with the reference surface (13). A countersunk platform (14) is provided between the reference surface (13) and the first annular platform (12). The upper surface of the countersunk platform (14) and the lower surface of the second annular platform (23) form the rough edge gap (5).

5. The polyurethane pneumatic tire centrifugal mold according to claim 1, characterized in that, The injection hole (22) is a conical hole that gradually expands from top to bottom, or the injection hole (22) is an inverted funnel-shaped hole.

6. The polyurethane pneumatic tire centrifugal mold according to claim 1, characterized in that, The upper mold (2) or lower mold (1) is provided with an exhaust hole (6) that communicates with the rough edge gap (5).

7. A polyurethane pneumatic tire centrifugal mold according to claim 6, characterized in that, The vent (6) is a stepped hole that is larger at the top and smaller at the bottom, located on the upper mold (2). The lower end of the stepped hole is connected to the rough edge gap (5).

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