An automatic inflatable rubber ball and a method for manufacturing the same

Abstract

The application discloses to the technical field of rubber ball production, in particular to an automatic inflatable rubber ball and a preparation method thereof. The automatic inflatable rubber ball comprises a hollow spherical body and an elastic inflation valve arranged on the spherical surface of the hollow spherical body. The resilience of the rubber ball after automatic inflation is 60-80%, the average wall thickness of the hollow spherical body is 1.5-6 mm, and the average external diameter is 100-200 mm. The elastic inflation valve comprises a valve body and a ventilation hole penetrating through the valve body in the thickness direction of the hollow spherical body. The cross-sectional diameter of the ventilation hole is 0.01-2 mm. The automatic inflatable rubber ball of the application can realize automatic inflation by directly inserting a pumping needle when inflation is needed, without using a pump.

Description

Technical Field

[0001] This application relates to the field of rubber ball production technology, and in particular to an automatically inflatable rubber ball and its preparation method. Background Technology

[0002] There are two main types of rubber balls on the market. One type is an inflatable rubber ball similar to a soccer ball or basketball. It has a valve on the ball, and when the air inside the ball is insufficient, an air pump is needed to inflate the ball. The other type is a sealed rubber ball, which has a one-piece structure without a valve. If it leaks air, it cannot be inflated and cannot be used.

[0003] Rubber balls, including toy rubber balls, are usually flattened to reduce their volume in order to save on transportation costs. However, they need to be inflated before being sold or acquired by the buyer. Additionally, inflated toy balls need to be re-inflated if they leak air.

[0004] The existing inflatable rubber balls have the following problems in inflation: (1) They require an air pump, which increases costs; (2) The air pump is not frequently used and may be lost, affecting subsequent inflation; (3) The air pump is not suitable for children to use, which reduces the children's experience of playing with rubber balls.

[0005] Therefore, developing an automatically inflatable rubber ball has significant practical implications. Summary of the Invention

[0006] To address the issues of existing inflatable rubber balls requiring an air pump for inflation and sealed rubber balls being unable to be flattened during transport, the inventors, through extensive experimentation, discovered that the rubber ball's resilience and structural design are two key factors for achieving automatic inflation. Therefore, this application provides an automatically inflatable rubber ball and its preparation method.

[0007] The present invention adopts the following technical solution: An automatically inflatable rubber ball, the rubber ball comprising a hollow sphere and an elastic inflation valve disposed on the spherical surface of the hollow sphere; The elasticity of the rubber ball after automatic inflation is 60-80%. The hollow sphere has an average wall thickness of 1.5-6 mm and an average outer diameter of 100-200 mm. The elastic inflation valve includes a valve body and a vent hole that penetrates the valve body along the wall thickness direction of the hollow sphere. The cross-sectional diameter of the vent hole is 0.01-2 mm.

[0008] Preferably, the ratio of the average wall thickness to the average outer diameter of the hollow sphere is 0.015-0.06.

[0009] Preferably, the ratio of the average wall thickness to the average outer diameter of the hollow sphere is 0.025-0.045.

[0010] Preferably, the average dimension of the valve body along the surface of the hollow sphere is 0.05-0.1 times the average outer diameter of the hollow sphere.

[0011] Preferably, the valve body includes a protruding portion that protrudes toward the center of the hollow sphere.

[0012] More preferably, the height of the protruding portion is 0.5-1.5cm.

[0013] More preferably, the protruding portion has a recessed structure in the middle.

[0014] More preferably, the middle part of the protruding portion has a flat structure.

[0015] More preferably, a shrinking member is fitted over the protruding portion to cause the protruding portion to shrink and deform.

[0016] More preferably, the tightening element is selected from O-rings or rubber bands.

[0017] More preferably, the tightening element is selected from clamps.

[0018] A method for preparing an automatically inflatable rubber ball according to any of the above embodiments includes the following steps: S1: The first rubber sheet is placed in a mold and hot-pressed for vulcanization to form the first hemisphere; the second rubber sheet is placed in a mold and hot-pressed for vulcanization to form the second hemisphere; S2: Grind the open end faces of the first and second hemispheres obtained in step S1 to form rough surfaces; S3: Install the elastic inflation valve on the first hemisphere, and apply glue to the rough surfaces of the first hemisphere and the second hemisphere respectively, and then bond the rough surfaces of the first hemisphere and the second hemisphere together to obtain a spherical blank. S4: Place the ball blank obtained in step S3 into a mold for secondary vulcanization molding to obtain the automatically inflatable rubber ball.

[0019] Preferably, in step S1, the first rubber sheet and the second rubber sheet are prepared by weight of the following raw materials: 60-80 parts natural rubber, 10-20 parts butadiene rubber, 5-15 parts reinforcing agent, 1-5 parts antioxidant, 1-2 parts accelerator, 0.5-3 parts colorant, and 0.5-1 part sulfur.

[0020] Preferably, in step S1, the hot-press vulcanization of the first rubber sheet and the hot-press vulcanization of the second rubber sheet each include two stages of hot-press vulcanization: the first stage of hot-press vulcanization is vulcanization at 90-100℃ for 3-5 minutes, and the second stage of hot-press vulcanization is vulcanization at 120-130℃ for 3-5 minutes.

[0021] Preferably, after the elastic inflation valve described in step S3 is installed on the first hemisphere, glue is applied to the installation position and left to dry for 0.5-24 hours.

[0022] Preferably, the secondary vulcanization molding in step S4 is vulcanization at 160-180℃ for 5-10 minutes.

[0023] In summary, this application includes at least one of the following beneficial technical effects: (1) This invention proposes an automatically inflatable rubber ball. By designing the elasticity and structure of the rubber ball and using a straight-through elastic inflation valve, when the rubber ball is not fully inflated, an air injection needle can be directly inserted to achieve automatic inflation of the rubber ball without the need for an air pump, providing a superior user experience.

[0024] (2) The rubber ball of the present invention can release the air inside the ball during transportation, making it deflated and reducing the volume of the ball by a lot, saving at least 30% of the transportation space, which can significantly save transportation costs, reduce costs, and make it more competitive in the market.

[0025] (3) The rubber ball of the present invention has good resilience after automatic inflation, making it suitable for use as a toy ball. Moreover, through the structural design of the elastic inflation valve, the rubber ball can maintain its inflation state for a long time after inflation, and it is easy to inflate when the air is insufficient. Attached Figure Description

[0026] Figure 1 This is a frontal view of the rubber ball in Example 1; Figure 2 This is a schematic diagram of the first hemisphere of the rubber ball in Example 1 with a reverse convex shape; Figure 3 This is a cross-sectional schematic diagram showing the reverse convexity of the first hemisphere of the rubber ball in Example 1; Figure 4 This is a diagram showing the state changes during the automatic inflation process of the rubber ball in Example 1.

[0027] Explanation of reference numerals in the attached figures: 1. Hollow sphere; 2. Valve body; 3. Vent hole; 4. Protruding part; 5. Middle part; 6. Tightening part. Detailed Implementation

[0028] The present invention provides an automatically inflatable rubber ball, the rubber ball comprising a hollow sphere and an elastic inflation valve disposed on the surface of the hollow sphere; The elasticity of a rubber ball after automatic inflation is 60-80%. The average wall thickness of the hollow sphere is 1.5-6 mm, and the average outer diameter is 100-200 mm. The flexible inflation valve includes a valve body and a vent hole that penetrates the valve body along the wall thickness direction of the hollow sphere. The cross-sectional diameter of the vent hole is 0.01-2 mm.

[0029] In this invention, automatic inflation of the rubber ball refers to the process where, after a flattened or underinflated rubber ball is inflated and an air inflator is inserted into the elastic inflation valve, external gas automatically enters the rubber ball, and the gas pressure inside the rubber ball gradually approaches the external pressure (such as atmospheric pressure) until the gas pressure inside the rubber ball reaches or approaches the external pressure. Using a conventional air inflator with an inner diameter of 2mm, this automatic inflation process usually takes less than 30 seconds. For larger rubber balls, such as those with an outer diameter of 190mm, automatic inflation takes approximately 25 seconds; for smaller rubber balls, such as those with an outer diameter of 120mm, automatic inflation takes approximately 10 seconds.

[0030] In this invention, the test method for resilience is as follows: place an automatically inflated rubber ball at a height of 1.8m above the ground and let it fall freely. After landing on a tiled floor, the rubber ball rebounds to a certain height h. Then, the resilience = h / 1.8×100%.

[0031] The resilience of the rubber ball in this invention serves two purposes: first, since the internal pressure of the rubber ball cannot reach the same level as that of a rubber ball inflated by an air pump, the ball needs to have good resilience in order to have good elasticity; second, good resilience of the rubber ball makes it easier to automatically inflate when flattened using an air pump.

[0032] In this invention, the cross-sectional diameter of the vent hole in the elastic vent valve is more preferably 0.01-1 mm. The vent hole can be straight (with the same or approximately the same cross-sectional diameter at all points), or it can be wider at the top and narrower at the bottom, with a smaller cross-sectional diameter near the center of the rubber ball, such as 0.02 mm, and a larger cross-sectional diameter further away from the center, such as 0.9 mm. Alternatively, it can be narrower at the top and wider at the bottom, with a larger cross-sectional diameter near the center of the rubber ball, such as 1 mm, and a smaller cross-sectional diameter further away from the center, such as 0.3 mm. The cross-sectional diameter of the vent hole in the elastic inflation valve is related to the leakage rate of the rubber ball; the larger the cross-sectional diameter, the faster the rubber ball leaks air, and the smaller the cross-sectional diameter, the slower the leakage. The inventors have found that when the cross-sectional diameter of the vent hole in the elastic inflation valve is 0.01-0.05 mm, the rubber ball can be maintained for 15-30 days of use with a single inflation.

[0033] In this invention, the material of the elastic inflation valve can be rubber, such as butadiene rubber, EPDM rubber, styrene-butadiene rubber, etc.

[0034] In a preferred embodiment of the present invention, the ratio of the average wall thickness of the hollow sphere to the average outer diameter is 0.015-0.06.

[0035] In a preferred embodiment of the present invention, the ratio of the average wall thickness of the hollow sphere to the average outer diameter is 0.025-0.045.

[0036] The inventors discovered that the ratio of the average wall thickness to the average outer diameter of the hollow sphere also affects the self-inflation performance of the rubber ball. A low ratio results in a soft rubber ball that is difficult to inflate automatically; a high ratio makes the rubber ball difficult to flatten and also results in high hardness, making it difficult to recover after being forcibly flattened and thus hindering self-inflation. Therefore, a suitable ratio of the average wall thickness to the average outer diameter of the hollow sphere improves the self-inflation performance of the rubber ball.

[0037] In a preferred embodiment of the present invention, the average dimension of the valve body along the surface of the hollow sphere is 0.05-0.1 times the average outer diameter of the hollow sphere.

[0038] The inventors discovered that adopting the above technical solution is advantageous for using elastic inflation valves of the same specification, which is beneficial for the production of rubber balls.

[0039] In a preferred embodiment of the present invention, the valve body includes a protruding portion that protrudes toward the center of the hollow sphere.

[0040] In a more preferred embodiment of the present invention, the height of the protruding portion is 0.5-1.5 cm.

[0041] The protruding part on the valve body makes production more convenient and allows for further adjustment of the cross-sectional diameter of the vent hole and the leakage rate after the rubber ball is inflated.

[0042] In a more preferred embodiment of the present invention, a recessed structure is present in the middle of the protruding portion.

[0043] In this invention, the protruding part can be roughly divided into three specific positions according to its location: the position near the center of the ball, the position near the valve body, and the middle position between the two positions.

[0044] The presence of a concave structure in the middle of the protruding part indicates that the outer surface curve of the longitudinal section at the middle point has a lowest point.

[0045] In a more preferred embodiment of the present invention, the middle part of the protruding portion has a flat structure.

[0046] The presence of a straight structure in the middle of the protruding part means that the outer surface curve of the longitudinal section in the middle is a straight line.

[0047] In a more preferred embodiment of the present invention, a tightening member is fitted over the protruding portion to cause the protruding portion to shrink and deform.

[0048] A shrink-fit element is fitted over the protruding part, typically positioned in the middle of the protruding part. This shrink-fit element causes the protruding part to contract and deform, reducing the diameter of the vent hole in the valve body. Since the valve body is elastic, this does not affect the insertion of the air injection needle or the automatic inflation via the needle, but it does reduce the leakage rate of the rubber bulb.

[0049] In a further preferred embodiment of the invention, the tightening element is selected from O-rings or rubber bands.

[0050] The elasticity of O-rings or rubber bands can be used to tighten and deform protruding parts, reducing the diameter of the vent hole in the valve body, and is also convenient to use. In this case, the inner diameter of the O-ring or rubber band is lower than the outer diameter of the protruding part's recessed or straight structure; for example, the inner diameter of the O-ring or rubber band is 85%, 90%, 93%, or 95% of the outer diameter of the protruding part's recessed or straight structure.

[0051] In a further preferred embodiment of the invention, the tightening element is selected from clamps.

[0052] Using clamps, protruding parts can be directly tightened and deformed, resulting in a smaller diameter of the valve body's vent hole, which improves stability and extends service life. The clamps can be adjusted in circumference, allowing for different degrees of tightening and deformation of the protruding parts, thus achieving the purpose of adjusting the diameter of the valve body's vent hole.

[0053] In another aspect, the present invention also provides a method for preparing an automatically inflatable rubber ball according to any of the above embodiments, comprising the following steps: S1: The first rubber sheet is placed in a mold and hot-pressed for vulcanization to form the first hemisphere; the second rubber sheet is placed in a mold and hot-pressed for vulcanization to form the second hemisphere; S2: Grind the open end faces of the first and second hemispheres obtained in step S1 to form rough surfaces; S3: Install the elastic inflation valve on the first hemisphere, apply glue to the rough surfaces of the first and second hemispheres respectively, and bond the rough surfaces of the first and second hemispheres together to obtain a spherical blank. S4: Place the ball blank obtained in step S3 into a mold for secondary vulcanization molding to obtain an automatically inflatable rubber ball.

[0054] First, prepare two hemispheres, then install an elastic inflation valve on one of the hemispheres. The process is simple, controllable, and more conducive to the operation of fitting a tightening component on the outside of the protruding part.

[0055] In a preferred embodiment of the present invention, the first rubber sheet and the second rubber sheet in step S1 are prepared by weight of the following raw materials: 60-80 parts natural rubber, 10-20 parts butadiene rubber, 5-15 parts reinforcing agent, 1-5 parts antioxidant, 1-2 parts accelerator, 0.5-3 parts colorant, and 0.5-1 part sulfur.

[0056] In this invention, both natural rubber and butadiene rubber are selected from commercially available conventional specifications; there are no particular restrictions on the reinforcing agent, which can be selected from commonly used reinforcing agents for natural rubber, such as carbon black, silica, activated calcium carbonate, hardening clay, etc.; there are no particular restrictions on the antioxidant, which can be selected from commonly used antioxidants for natural rubber, such as antioxidant AW, antioxidant A, antioxidant RD / TMQ, antioxidant D, antioxidant 4010NA, antioxidant 4010, antioxidant 4040, antioxidant ODA, etc.; there are no particular restrictions on the accelerator, which can be selected from commonly used accelerators for natural rubber, such as accelerator M, accelerator DM, accelerator TMTD, accelerator TMTM, accelerator TETD, accelerator ZDC, accelerator BZ, and accelerator D, etc.; there are no particular restrictions on the color powder, which can be selected from commonly used color powders for natural rubber, or it can be added in the form of color masterbatch.

[0057] In the above technical solution, natural rubber is used as the main rubber and cis-butadiene rubber with high flexibility is used as the auxiliary rubber, resulting in rubber balls with better resilience.

[0058] Because of the method of bonding two hemispheres together, the formulations of the first and second rubber sheets can be the same or different. Typically, the first and second rubber sheets are the same type of rubber, which is more convenient for production. Alternatively, the first and second rubber sheets can have different formulations, resulting in rubber balls with different properties such as elasticity and hardness, leading to different characteristics and a different feel on each side.

[0059] In a preferred embodiment of the present invention, the hot-press vulcanization of the first rubber sheet and the hot-press vulcanization of the second rubber sheet in step S1 each include two stages of hot-press vulcanization. The first stage of hot-press vulcanization is vulcanization at 90-100°C for 3-5 minutes, and the second stage of hot-press vulcanization is vulcanization at 120-130°C for 3-5 minutes.

[0060] The inventors discovered through experiments that using a two-stage vulcanization process during hot-press vulcanization results in rubber balls with higher resilience. This may be related to the different cross-linking states of the rubber balls obtained by the two-stage vulcanization process compared to a one-stage vulcanization process.

[0061] In a preferred embodiment of the present invention, after the elastic inflation valve is installed in the first hemisphere in step S3, glue is applied to the installation position and left to dry for 0.5-24 hours.

[0062] Applying adhesive to the mounting location of the flexible inflation valve and allowing it to air dry improves the valve's sealing performance, preventing air leakage at the connection point between the valve and the rubber bulb. This is a major cause of leakage in conventional inflatable rubber bulbs. Because the flexible inflation valve in this invention is installed on a hemisphere, installation is convenient, adhesive application is easy, and the sealing performance is better.

[0063] In a preferred embodiment of the present invention, the secondary vulcanization molding in step S4 is vulcanization at 160-180°C for 5-10 minutes.

[0064] In this invention, secondary vulcanization molding allows the rubber ball to be vulcanized more completely, resulting in stable performance.

[0065] The present invention will be further described below with reference to specific embodiments.

[0066] Example 1 Based on the weight proportions of each raw material component: 80 parts natural rubber, 15 parts butadiene rubber, and 10 parts BET with a specific surface area of ​​150 g / m². 2 The composition includes 1.5 parts silica, 1.5 parts antioxidant D, 1 part accelerator DM, 1 part phthalocyanine blue, 0.8 parts sulfur, 1.5 parts active zinc oxide, and 1 part tributyl acetylacetate. Pour natural rubber and butadiene rubber into a mixer, and control the mixing pressure at 5 kg / cm². 2 The mixing temperature is 100-110℃, and the mixing time is 6 minutes. Silica, antioxidant D, accelerator DM, phthalocyanine blue, and tributyl acetyl citrate were added to an internal mixer, and the mixing pressure was controlled at 4.5 kg / cm². 2 The mixing temperature is 110-120℃ and the mixing time is 5 minutes to obtain the mixed rubber. The intensively mixed rubber is placed into a two-roll mill and extruded repeatedly 6 times. After standing and cooling for 24 hours, it is sent back into the two-roll mill for further processing. Sulfur and zinc oxide are added, and the mixture is extruded repeatedly 7 times to obtain rubber sheets. A portion of the rubber sheet is placed in a mold and hot-pressed for vulcanization to form the first hemisphere; another portion of the rubber sheet is placed in a mold and hot-pressed for vulcanization to form the second hemisphere; Hot-press vulcanization employs a two-stage vulcanization process. The first stage involves vulcanization at 90°C for 5 minutes, while the second stage involves vulcanization at 120°C for 5 minutes, with a pressure of 12 MPa.

[0067] The open end faces of the first and second hemispheres are respectively polished to form rough surfaces; Install the elastic inflation valve in the middle of the first hemisphere and apply glue to the installation position. Let it dry at room temperature for 12 hours. Then apply glue to the rough surfaces of the first and second hemispheres and bond the rough surfaces of the first and second hemispheres together. Let it stand at room temperature for 2 hours to obtain the sphere blank. Place the ball blank in a mold and vulcanize it at 180°C for 8 minutes for secondary vulcanization molding. Remove it, cool it at room temperature for 24 hours, trim the edges, and you will get an automatically inflatable rubber ball.

[0068] The following is in conjunction with the appendix Figure 1-4 The structure of the self-inflating rubber ball is explained. Please see the appendix. Figure 1-3 The rubber ball includes a hollow sphere (1) and an elastic air valve disposed on the spherical surface of the hollow sphere (1). The elastic air valve is made of styrene-butadiene rubber. The elastic air valve includes a valve body (2) and an air vent (3) penetrating the valve body along the wall thickness direction of the hollow sphere (1). The air vent (3) is straight and has a cross-sectional diameter of 0.8 mm. The average wall thickness of the hollow sphere (1) is 4 mm, and the average outer diameter is 150 mm. The average dimension of the valve body along the spherical surface of the hollow sphere is 10 mm.

[0069] The valve body (2) also includes a protruding part (4) protruding towards the center of the hollow sphere (1). The height of the protruding part (4) is 0.9cm. The middle part (5) of the protruding part (4) is a concave structure with a circular cross-section. An O-ring (6) is fitted at the concave structure. The inner diameter of the O-ring (6) is 93% of the cross-sectional diameter of the concave structure at the corresponding fitting location.

[0070] Please see attached. Figure 4 After being deflated, the rubber ball is automatically inflated when inserted into the air syringe. The rubber ball gradually inflates and expands until it is full of gas. After 20 seconds of inflation, the rubber ball appears to be fully inflated. When placed at a height of 1.8m above the ground and allowed to fall freely, it bounces back to a height of 1.28m after hitting the tile floor, exhibiting a resilience of 71.1%.

[0071] After the rubber ball automatically filled with gas and was left to stand at room temperature for 15 days, the resilience was tested and found to be 70.4%. This indicates that the rubber ball of the present invention leaks very little gas when left to stand.

[0072] After the rubber ball was automatically inflated and tapped 200 times a day for 15 consecutive days, the resilience was tested at 64.3%. This indicates that after being tapped, the gas inside the rubber ball is expelled due to the compression and deformation of the ball, resulting in a decrease in gas pressure inside the ball. After continued automatic inflation with the air syringe inserted, the resilience of the rubber ball was tested at 70.7%. This demonstrates that the automatically inflatable rubber ball of this invention can regain its resilience after repeated automatic inflation.

[0073] Example 2 In Example 1, the hot-press vulcanization was carried out in a single stage, with the hot-press vulcanization temperature being 90°C for 10 minutes and the pressure being 12 MPa. The remaining steps remained unchanged, and the elasticity of the rubber ball after automatic inflation was 68.3%.

[0074] Example 3 In Example 1, the hot-press vulcanization was carried out in a single stage, with the hot-press vulcanization being carried out at 120°C for 10 minutes at a pressure of 12 MPa. The remaining steps remained unchanged, and the elasticity of the rubber ball after automatic inflation was 69.6%.

[0075] Example 4 The rubber sheet obtained in Example 1 is used. A portion of the rubber sheet is placed in a mold and hot-pressed and vulcanized to form a first hemisphere; another portion of the rubber sheet is placed in a mold and hot-pressed and vulcanized to form a second hemisphere; the surface of the second hemisphere has a through hole penetrating the second hemisphere, and the cross-sectional diameter of the through hole is 0.04 mm.

[0076] Hot-press vulcanization employs a two-stage vulcanization process. The first stage involves vulcanization at 90°C for 5 minutes, while the second stage involves vulcanization at 120°C for 5 minutes, with a pressure of 12 MPa.

[0077] The open end faces of the first and second hemispheres are polished to form rough surfaces; glue is applied to the rough surfaces of the first and second hemispheres, and the rough surfaces of the first and second hemispheres are joined and bonded together. The mixture is left at room temperature for 2 hours to obtain a sphere blank. Place the ball blank in a mold and vulcanize it at 180℃ for 9 minutes for secondary vulcanization molding. Remove it, cool it at room temperature for 24 hours, trim the edges, and obtain an automatically inflatable rubber ball.

[0078] The hollow sphere (1) of the rubber ball in this embodiment has an average wall thickness of 3 mm and an average outer diameter of 160 mm. It is automatically inflated by inserting an air needle into the through-hole. After being fully inflated, the resilience of the rubber ball is tested to be 63.5%.

[0079] Example 5 An automatically inflatable rubber ball was prepared according to the preparation method in Example 1. When the rubber sheet was hot-pressed and vulcanized to form the first and second hemispheres, the hot-pressing vulcanization was performed at 100°C for 10 minutes at a pressure of 15 MPa. The rubber ball includes a hollow sphere (1) and an elastic inflation valve disposed on the spherical surface of the hollow sphere (1). The elastic inflation valve is made of styrene-butadiene rubber. The elastic inflation valve includes a valve body (2) and a vent hole (3) penetrating the valve body along the wall thickness direction of the hollow sphere (1). The vent hole (3) has a shape that is wider at the top and narrower at the bottom, with a cross-sectional diameter of 0.08 mm near the center of the rubber ball and a cross-sectional diameter of 1.5 mm away from the center. The average wall thickness of the hollow sphere (1) is 3 mm, and the average outer diameter is 110 mm. The average dimension of the valve body along the spherical surface of the hollow sphere is 10 mm.

[0080] The valve body (2) also includes a protruding part (4) protruding towards the center of the hollow sphere (1). The height of the protruding part (4) is 1cm. The middle part (5) of the protruding part (4) is a concave structure with a circular cross-section. An O-ring (6) is fitted at the concave structure. The inner diameter of the O-ring (6) is 90% of the cross-sectional diameter of the concave structure at the corresponding fitting location.

[0081] After being deflated, the rubber ball is automatically inflated when inserted into the air syringe. The rubber ball gradually inflates and expands until it is full of gas. After 12 seconds of inflation, the rubber ball appears to be fully inflated. When placed at a height of 1.8m above the ground and allowed to fall freely, it bounces back to a height of 1.34m after hitting the tiled floor, exhibiting a resilience of 74.7%.

[0082] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A self-inflating rubber ball, characterized in that, The rubber ball includes a hollow sphere (1) and an elastic inflation valve disposed on the spherical surface of the hollow sphere (1); The elasticity of the rubber ball after automatic inflation is 60%. 80%; The average wall thickness of the hollow sphere is 1.

5. 6mm, with an average outer diameter of 100. 200mm; The elastic inflation valve includes a valve body (2) and a vent (3) penetrating the valve body (2) along the wall thickness direction of the hollow sphere (1), wherein the cross-sectional diameter of the vent (3) is 0.

01. 2mm; The automatic inflation refers to the following: after a deflated ball or an inflatable ball is inserted into a conventional air injection needle, external gas automatically enters through the vent (3), making the pressure inside the ball close to atmospheric pressure, without the need for an air pump.

2. The automatically inflatable rubber ball according to claim 1, characterized in that, The ratio of the average wall thickness to the average outer diameter of the hollow sphere (1) is 0.

015. 0.

06.

3. The automatically inflatable rubber ball according to claim 1, characterized in that, The ratio of the average wall thickness to the average outer diameter of the hollow sphere (1) is 0.

025. 0.

045.

4. The automatically inflatable rubber ball according to claim 1, characterized in that, The average dimension of the valve body (2) along the spherical surface of the hollow sphere (1) is 0.05 times the average outer diameter of the hollow sphere (1). 0.

1.

5. The automatically inflatable rubber ball according to claim 1, characterized in that, The valve body (2) includes a protruding part (4) that protrudes toward the center of the hollow sphere (1).

6. The automatically inflatable rubber ball according to claim 5, characterized in that, The height of the protruding part (4) is 0.

5. 1.5cm.

7. The automatically inflatable rubber ball according to claim 5, characterized in that, There is a recessed structure in the middle (5) of the protruding part (4).

8. The automatically inflatable rubber ball according to claim 5, characterized in that, The middle part (5) of the protruding part (4) is a flat structure.

9. The automatically inflatable rubber ball according to claim 5, characterized in that, The protruding part (4) is fitted with a shrinking member (6) to cause the protruding part (4) to shrink and deform.

10. The automatically inflatable rubber ball according to claim 9, characterized in that, The tightening element (6) is selected from O-rings or rubber bands.

11. The automatically inflatable rubber ball according to claim 9, characterized in that, The tightening component (6) is selected from clamps.

12. A claim 1 The method for preparing an automatically inflatable rubber ball according to any one of the 11 claims is characterized in that, Includes the following steps, S1: The first rubber sheet is placed in a mold and hot-pressed for vulcanization to form the first hemisphere; the second rubber sheet is placed in a mold and hot-pressed for vulcanization to form the second hemisphere; S2: Grind the open end faces of the first and second hemispheres obtained in step S1 to form rough surfaces; S3: Install the elastic inflation valve on the first hemisphere, and apply glue to the rough surfaces of the first hemisphere and the second hemisphere respectively, and then bond the rough surfaces of the first hemisphere and the second hemisphere together to obtain a spherical blank. S4: Place the ball blank obtained in step S3 into a mold for secondary vulcanization molding to obtain the automatically inflatable rubber ball.

13. The preparation method according to claim 12, characterized in that, In step S1, the first rubber sheet and the second rubber sheet are prepared individually from the following raw materials in parts by weight: 60 80 parts natural rubber, 10 20 parts butadiene rubber, 5 15 portions of reinforcing agent, 1 5 parts anti-aging agent, 1 2 parts accelerator, 0.5 3 parts color powder, 0.5 1 part sulfur.

14. The preparation method according to claim 12, characterized in that, Step S1, the hot-press vulcanization of the first rubber sheet and the hot-press vulcanization of the second rubber sheet each include two stages of hot-press vulcanization. The first stage of hot-press vulcanization is 90°C. 100℃ vulcanization 3 5 minutes, the second stage of hot-press vulcanization is 120 130℃ vulcanization 3 5 minutes.

15. The preparation method according to claim 12, characterized in that, After the elastic inflation valve described in step S3 is installed on the first hemisphere, glue is applied to the installation position, and it is left to dry for 0.5 seconds. 24 hours.

16. The preparation method according to claim 12, characterized in that, The secondary vulcanization molding described in step S4 is 160. 180℃ vulcanization 5 10 minutes.

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