A ball wear-resistant sheet

Abstract

The present invention provides a ball wear-resistant sheet, which belongs to the field of mold technology. It solves the problems of high installation precision requirements and easy rolling jam of balls in existing ball sheets. The ball wear-resistant sheet includes a base plate and a cover plate, and a plurality of balls are installed between the base plate and the cover plate. Through holes corresponding to the balls are provided on the cover plate, and the tops of the balls extend out of the cover plate from the corresponding through holes. A sponge layer for absorbing lubricants is also fixed between the base plate and the cover plate, and mounting holes corresponding to the balls are provided on the sponge layer, and the balls are interference fitted in the mounting holes. The ball wear-resistant sheet reduces the installation precision requirements and can make the balls roll smoothly.

Description

Technical Field

[0001] The invention belongs to the technical field of molds and relates to a ball wear-resistant sheet. Background Art

[0002] Most plastic products are molded by injection molding. The injection mold includes a fixed mold and a movable mold. When the fixed mold and the movable mold are closed, a cavity is formed, and the plastic product is molded in the cavity. In order to accurately position the fixed mold and the movable mold when closing the mold and prevent shaking after closing the mold, a locking structure is set between the fixed mold and the movable mold. The locking structure includes a notch set on the fixed mold and a positioning block set on the movable mold. The side of the notch is inclined, and the positioning block is inserted into the notch to form a conical matching structure, so that the fixed mold and the movable mold are locked and stable after closing the mold. In order to reduce friction and wear during the closing process, a wear-resistant sheet is generally fixed on the side of the notch.

[0003] The mold will be heated during injection molding, which will cause the wear-resistant sheet to deform or change in accuracy after being heated. In this way, the wear-resistant sheet will often get stuck and make abnormal noises when the mold is opened, resulting in strain and iron powder falling into the cavity due to friction, causing the product to be scrapped. In order to reduce the impact of heating, the material of the wear-resistant sheet is generally upgraded to use heat-resistant alloy materials, but this will increase the material cost, or reduce the heating temperature of injection molding, but this will affect the molding quality of the product, or increase the inclination angle of the wear-resistant sheet installation, but the increase in the inclination angle will lead to a decrease in the stability of the clamping positioning, which will also affect the molding quality of the product.

[0004] Designers have also considered replacing the wear-resistant sheet with a ball sheet. Ordinary ball sheets include a base plate, a cover plate, and a ball. In order to install and position the ball, a hemispherical bottom groove is opened on the base plate, and a hemispherical top groove is set on the cover plate. After the base plate and the cover plate are covered, the hemispherical bottom groove and the hemispherical top groove are combined into a spherical cavity. The ball is installed in the spherical cavity, and the top of the ball extends out of the cover plate. A ball sheet is often arranged with several balls, so it is necessary to accurately align the hemispherical bottom grooves and hemispherical top grooves corresponding to the balls, that is, the installation accuracy is high. Once the installation accuracy is insufficient, there will be a position error between the hemispherical bottom groove and the hemispherical top groove, which will cause the ball to be stuck in the spherical cavity and unable to rotate. In addition, since the injection mold is still in a special working condition such as heating, the installation accuracy of the ordinary ball sheet will deteriorate after being heated, which will also cause the ball to be stuck in the spherical cavity and unable to rotate, and finally it will still cause mold opening strain and abnormal noise. Summary of the invention

[0005] The purpose of the present invention is to solve the above problems existing in the prior art and propose a ball wear-resistant sheet to solve the technical problems of high installation accuracy requirements and easy rolling jam of the ball in the existing ball sheets.

[0006] The purpose of the present invention can be achieved by the following technical solutions:

[0007] A ball wear-resistant sheet comprises a base plate and a cover plate, a plurality of balls are installed between the base plate and the cover plate, through holes corresponding to the balls are opened on the cover plate, and the tops of the balls extend out of the cover plate from the corresponding through holes. The sheet is characterized in that a sponge layer for absorbing lubricant is fixed between the base plate and the cover plate, mounting holes corresponding to the balls are opened on the sponge layer, and the balls are interference fitted in the mounting holes.

[0008] Since the mounting hole of the sponge layer is fitted with the ball by interference fit, and the sponge layer has a certain elasticity, the sponge layer and the ball are elastically pressed against each other, so that the lubricant adsorbed on the sponge layer is in full contact with the ball. As the ball rolls, the sponge layer can fully apply the lubricant to the outer surface of the ball, so that the lubricant fully lubricates the outer surface of the ball, reducing the friction coefficient and friction force, and reducing the possibility of the ball getting stuck when the wear-resistant sheet is in use. In the process of assembling the ball wear-resistant sheet, the ball can be positioned and installed in the mounting hole of the sponge layer first, and then the sponge layer can be installed between the cover plate and the bottom plate. Even if there is a position error between the through hole of the cover plate and the mounting hole of the sponge layer due to insufficient installation accuracy, the sponge layer has a certain elasticity, and the ball can be adaptively moved in the sponge layer, so that the ball is accurately embedded in the through hole of the cover plate, avoiding the ball from getting stuck and unable to roll. At the same time, after the ball moves adaptively, it can also be pressed against the hole wall of the mounting hole for positioning and lubrication by utilizing the interference fit state with the sponge layer and the elasticity of the sponge layer. Moreover, the lubricant and sponge layer also have a certain heat insulation effect, reducing the heat transfer to the cover plate to cause the cover plate to be overheated and deformed, preventing the cover plate from being too deformed and causing the ball to be stuck, so that the ball can roll smoothly in the wear-resistant sheet. Therefore, the ball wear-resistant sheet reduces the installation accuracy requirements and can make the ball roll smoothly.

[0009] In addition, sponges are generally used for collision prevention, but the present invention applies sponges to ball wear-resistant sheets for lubrication and installation positioning, so as to reduce the installation accuracy requirements of ball wear-resistant sheets and improve the rolling smoothness of the balls, thus expanding the application scope of sponges. Interference fitting is generally used for fixing two parts, but the present invention uses interference fitting to improve the rolling smoothness of the balls, thus expanding the application scope of interference fitting.

[0010] In the above-mentioned ball wear-resistant sheet, a groove is provided on the bottom surface of the cover plate, the sponge layer is embedded in the groove, and the outer side surface of the sponge layer is in contact with the side surface of the groove.

[0011] The groove has a positioning effect on the sponge layer. During the assembly of the wear-resistant sheet, when the ball moves adaptively, the sponge layer can be prevented from moving, thereby avoiding excessive relative movement between the ball and the sponge layer, which may cause a part of the ball surface to separate from the wall of the mounting hole. This ensures that the ball and the wall of the mounting hole are fully in contact for positioning and lubrication, which is beneficial to ensure smooth rolling of the ball.

[0012] In the above-mentioned ball wear-resistant sheet, the top surface of the sponge layer elastically sticks to the bottom surface of the groove, the bottom surface of the sponge layer elastically sticks to the top surface of the bottom plate, and the bottom of the ball sticks to the bottom plate.

[0013] During the process of covering the cover plate and the bottom plate, the cover plate and the bottom plate clamp the sponge layer to cause elastic compression of the sponge layer. After the cover plate and the bottom plate are fixed, the sponge layer can be elastically pressed against the cover plate and the bottom plate, and at the same time, the bottom of the ball can be exposed to form a rigid contact with the sponge layer and the bottom plate, thereby ensuring the positioning stability and accuracy of the ball wear-resistant sheet when used for clamping in the injection mold.

[0014] In the above-mentioned ball wear-resistant sheet, the hole wall of the mounting hole is a spherical surface, and the middle of the ball is located in the mounting hole. When the ball is not installed, the diameter of the mounting hole is smaller than the diameter of the ball. In this way, the ball and the mounting hole can form an interference fit, and the entire mounting hole fits the ball, which can more fully apply lubricating oil to the ball, so that the ball rolls smoothly; the hole wall of the mounting hole is a spherical surface, which can also make the elastic force of the sponge layer on the ball toward the center of the ball, forming a lifting force on the ball toward the cover plate, so that the ball is stably positioned in the through hole of the cover plate. The middle of the ball is located in the mounting hole, which can also prevent the ball from being unable to be embedded in the through hole of the cover plate.

[0015] In the above-mentioned ball wear-resistant sheet, the hole wall of the mounting hole is a cylindrical surface, the diameter of the mounting hole is smaller than the diameter of the ball, and the middle of the ball is located in the mounting hole and has interference fit. This can reduce the resistance of the ball when it moves adaptively during the assembly of the wear-resistant sheet, so that the ball can smoothly complete the adaptive movement and the ball can rotate smoothly.

[0016] In the above-mentioned ball wear-resistant sheet, the bottom surface of the cover plate is provided with several protruding positioning columns, the sponge layer is provided with perforations corresponding to the positioning columns one by one, and the bottom plate is provided with positioning holes corresponding to the positioning columns one by one. The positioning columns are inserted into and fixed in the corresponding positioning holes after passing through the corresponding perforations.

[0017] The positioning column can prevent the sponge layer from rotating between the cover plate and the bottom plate, so that the through hole of the cover plate can be aligned with the mounting hole for installation, avoiding the large position deviation between the through hole and the mounting hole caused by the sponge layer rotating too much during the assembly of the wear-resistant sheet, which is conducive to ensuring the smooth rolling of the ball. In addition, the positioning column can simultaneously position the sponge layer and fix the cover plate and the bottom plate, making the assembly of the ball wear-resistant sheet convenient.

[0018] In the above-mentioned ball wear-resistant sheet, the top surface of the bottom plate is a plane, and the bottom of the ball abuts against the top surface of the bottom plate.

[0019] At this time, the ball and the base plate form point contact, and the ball will not be restricted by the base plate when it performs adaptive movement during the assembly of the wear-resistant plate, which is conducive to smooth rolling of the ball. At the same time, this setting does not require any requirements on the installation accuracy of the through holes of the base plate and the cover plate, and also reduces the installation accuracy requirements.

[0020] In the above-mentioned ball wear-resistant sheet, the thickness of the bottom plate is greater than the diameter of the ball. The thickness of the bottom plate is the distance between the top surface and the bottom surface of the bottom plate. Increasing the thickness of the bottom plate can reduce the deformation of the bottom plate caused by heat, so that the ball rolls smoothly.

[0021] In the above-mentioned ball wear-resistant sheet, the positioning column is provided with a stepped bolt hole. Bolts can be inserted into the bolt holes to facilitate the installation and fixing of the ball wear-resistant sheet to the injection mold. The bolt holes are provided in the positioning column, which can also reduce the damage to the sponge layer structure when the bolt holes are provided in other positions, thereby ensuring that the function of the sponge layer can be realized.

[0022] Compared with the prior art, the present invention has the following advantages:

[0023] A sponge layer for absorbing lubricant is set between the bottom plate and the cover plate, and the ball is embedded in the installation hole of the sponge layer and interference fit. The adaptive movement of the ball during the assembly of the wear-resistant sheet can reduce the installation accuracy requirements while allowing the ball to roll smoothly. A groove is set on the cover plate, and the sponge layer is embedded in the groove for positioning to prevent the sponge layer from moving during the assembly of the wear-resistant sheet, so that the assembly process goes smoothly and the smoothness of the ball rolling is guaranteed. A positioning column is set on the cover plate, which can not only position the sponge layer to prevent the sponge layer from rotating, but also fix the cover plate and the bottom plate. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a three-dimensional diagram of the first embodiment of the ball wear-resistant sheet.

[0025] Figure 2 It is a cross-sectional view of the first embodiment of the ball wear-resistant sheet.

[0026] Figure 3 It is a cross-sectional view of the second embodiment of the ball wear-resistant sheet.

[0027] In the figure, 1, base plate; 1a, positioning hole; 1b, embedding groove; 2, cover plate; 2a, through hole; 2b, groove; 2c, positioning column; 2d, bolt hole; 3, ball bearing; 4, sponge layer; 4a, mounting hole; 4b, through hole; 5, bolt. DETAILED DESCRIPTION

[0028] The following are specific embodiments of the present invention and the accompanying drawings to further describe the technical solution of the present invention, but the present invention is not limited to these embodiments.

[0029] Embodiment 1

[0030] like Figure 1 and Figure 2 As shown, a ball wear-resistant sheet includes a base plate 1 and a cover plate 2, and a plurality of balls 3 are installed between the base plate 1 and the cover plate 2, and all the balls 3 are arranged in an array. The cover plate 2 is provided with through holes 2a corresponding to the balls 3 one by one, and the tops of the balls 3 extend out of the cover plate 2 from the corresponding through holes 2a. The wall surface of the through hole 2a can be a spherical surface, a conical surface, or a cylindrical surface. When the wall surface of the through hole 2a is a spherical surface, the spherical diameter of the through hole 2a is greater than or equal to the diameter of the ball 3, and the aperture diameter of the through hole 2a at the top surface of the cover plate 2 is smaller than the diameter of the ball 3; when the wall surface of the through hole 2a is a conical surface, the minimum diameter of the through hole 2a is smaller than the diameter of the ball 3; when the wall surface of the through hole 2a is a cylindrical surface, the diameter of the through hole 2a is smaller than the diameter of the ball 3. The base plate 1 and the cover plate 2 are both symmetrical structures.

[0031] like Figure 2 As shown, the bottom surface of the cover plate 2 is in contact with the top surface of the base plate 1, and the outer side surface of the cover plate 2 is flush with the outer side surface of the base plate 1. A sponge layer 4 for absorbing lubricant is also fixed between the base plate 1 and the cover plate 2. The lubricant can be lubricating oil or grease. The sponge layer 4 is provided with mounting holes 4a corresponding to the balls 3 one by one, and the balls 3 are embedded in the mounting holes 4a, and the mounting holes 4a and the balls 3 are interference fitted. The hole wall surface of the mounting hole 4a is a spherical surface, and the middle part of the balls 3 is located in the mounting hole 4a. When the balls 3 are not installed, the diameter of the mounting hole 4a is smaller than the diameter of the balls 3. A groove 2b is provided on the bottom surface of the cover plate 2, and the sponge layer 4 is embedded in the groove 2b, and the outer side surface of the sponge layer 4 is all in contact with the side surface of the groove 2b. The top surface of the sponge layer 4 elastically contacts the bottom surface of the groove 2b, and the bottom surface of the sponge layer 4 elastically contacts the top surface of the base plate 1, and the bottom of the balls 3 contacts the base plate 1. The top surface of the bottom plate 1 is a plane, and the bottom of the ball 3 abuts against the top surface of the bottom plate 1, so that point contact is formed between the ball 3 and the bottom plate 1. In order to reduce the deformation of the bottom plate 1 due to heat, the thickness of the bottom plate 1 is greater than the diameter of the ball 3, and the thickness of the bottom plate 1 is generally greater than twice the diameter of the ball 3. There are several protruding positioning columns 2c on the bottom surface of the cover plate 2, and the sponge layer 4 is provided with perforations 4b corresponding to the positioning columns 2c. The bottom plate 1 is provided with positioning holes 1a corresponding to the positioning columns 2c. The positioning columns 2c are inserted and fixed in the corresponding positioning holes 1a after passing through the corresponding perforations 4b. The positioning columns 2c and the perforations 4b can be interference fit or clearance fit. The positioning columns 2c and the positioning holes 1a are fixed by interference fit or the positioning columns 2c are fixed by welding after being inserted into the positioning holes 1a. In this embodiment, two positioning columns 2c are provided, and the two positioning columns 2c are symmetrically arranged. A stepped bolt hole 2d is provided in the positioning column 2c, and a bolt 5 is passed through the bolt hole 2d, so as to facilitate the installation of the ball wear-resistant sheet on the injection mold.

[0032] The ball wear-resistant sheet can be fixed to the side of the notch of the fixed mold of the injection mold with bolts 5, the bottom plate 1 is against the side of the notch, and the top of the ball 3 faces the notch. When closing the mold, the positioning block of the movable mold is inserted into the notch, and the side of the positioning block is against the top of the ball 3. When opening the mold, the positioning block is pulled out of the notch. During the mold opening and closing process, there is rolling friction between the positioning block and the ball 3, and there is point contact between the positioning block and the ball 3, which reduces the friction coefficient and friction area, thereby reducing the friction force, which is conducive to avoiding mold opening jamming and abnormal noise.

[0033] Since the mounting hole 4a of the sponge layer 4 is kept in close contact with the ball 3 due to the interference fit, the lubricant absorbed on the sponge layer 4 can fully contact the ball 3. As the ball 3 rolls, the sponge layer 4 can fully apply the lubricant to the outer surface of the ball 3, so that the lubricant can fully lubricate the outer surface of the ball 3, reducing the friction and reducing the possibility of the ball 3 getting stuck when the wear-resistant sheet is in use.

[0034] In the process of assembling the ball wear-resistant sheet, the ball 3 can be first positioned and installed in the mounting hole 4a of the sponge layer 4, and then the sponge layer 4 can be embedded in the groove 2b for positioning to prevent the sponge layer 4 from moving as a whole. At this time, since the sponge layer 4 has a certain elasticity, even if there is a position error between the through hole 2a of the cover plate 2 and the mounting hole 4a of the sponge layer 4 due to insufficient installation accuracy, the ball 3 can also move adaptively in the sponge layer 4, so that the ball 3 is accurately embedded in the through hole 2a of the cover plate 2, avoiding the ball 3 from being stuck and unable to roll due to insufficient accuracy. Moreover, after the ball 3 moves adaptively, the interference fit state with the sponge layer 4 and the elasticity of the sponge layer 4 can be utilized to keep the ball 3 in contact with the hole wall of the mounting hole 4a for positioning and lubrication; then lubricant is added to the sponge layer 4, and then the base plate 1 is placed against the bottom surface of the cover plate 2, the positioning column 2c is inserted into the positioning hole 1a and fixed, and the base plate 1 presses the sponge layer 4 so that the bottom of the ball 3 is exposed through the mounting hole 4a and rests on the base plate 1. In addition, the lubricant and the sponge layer 4 also have a certain heat insulation effect, reducing the heat transfer to the cover plate 2 causing the overheating deformation of the cover plate 2, preventing the cover plate 2 from deforming too much and causing the ball 3 to be stuck, so that the ball 3 can roll smoothly in the wear-resistant sheet. Therefore, the ball wear-resistant sheet reduces the installation accuracy requirements and can make the ball 3 roll smoothly.

[0035] Embodiment 2

[0036] like Figure 3As shown, the difference from the first embodiment is that: the hole wall surface of the mounting hole 4a is a cylindrical surface, and the diameter of the mounting hole 4a is smaller than the diameter of the ball 3 when the ball 3 is not installed; after the ball 3 is installed in the mounting hole 4a, the middle of the ball 3 is located in the mounting hole 4a and interferes. A groove 1b corresponding to the ball 3 is provided on the top surface of the bottom plate 1, and the bottom of the ball 3 is embedded in the groove 1b. The groove wall surface of the groove 1b is a spherical surface, and the spherical diameter of the groove 1b is greater than or equal to the diameter of the ball 3; in order to reduce the installation accuracy requirement, it is preferred to set the spherical diameter of the groove 1b to be greater than the diameter of the ball 3. In order to further reduce the installation accuracy requirement, the groove 1b is set as a rectangular parallelepiped groove, so that the bottom of the ball 3 abuts against the bottom surface of the groove 1b to form a point contact. The other structures are the same as the first embodiment.

[0037] The specific embodiments described herein are merely examples of the spirit of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in similar ways, but they will not deviate from the spirit of the present invention or exceed the scope defined by the appended claims.

Claims

1. A ball wear-resistant sheet, comprising a base plate (1) and a cover plate (2), wherein a plurality of balls (3) are mounted between the base plate (1) and the cover plate (2), wherein the cover plate (2) is provided with through holes (2a) corresponding to the balls (3) one by one, and the tops of the balls (3) extend out of the cover plate (2) from the corresponding through holes (2a), wherein: A sponge layer (4) for absorbing lubricant is also fixed between the base plate (1) and the cover plate (2), and mounting holes (4a) corresponding one to one with the balls (3) are provided on the sponge layer (4), and the balls (3) are interference-fitted in the mounting holes (4a).

2. The ball wear-resistant sheet according to claim 1, characterized in that: A groove (2b) is provided on the bottom surface of the cover plate (2), the sponge layer (4) is embedded in the groove (2b), and the outer side surface of the sponge layer (4) is in contact with the side surface of the groove (2b).

3. The ball wear-resistant sheet according to claim 2, characterized in that: The top surface of the sponge layer (4) elastically abuts against the bottom surface of the groove (2b), the bottom surface of the sponge layer (4) elastically abuts against the top surface of the bottom plate (1), and the bottom of the ball (3) abuts against the bottom plate (1).

4. The ball wear-resistant sheet according to any one of claims 1 to 3, characterized in that: The wall surface of the mounting hole (4a) is a spherical surface, and the middle of the ball (3) is located in the mounting hole (4a); when the ball (3) is not installed, the diameter of the mounting hole (4a) is smaller than the diameter of the ball (3).

5. The ball wear-resistant sheet according to any one of claims 1 to 3, characterized in that: The wall surface of the mounting hole (4a) is a cylindrical surface, the diameter of the mounting hole (4a) is smaller than the diameter of the ball (3), and the middle of the ball (3) is located in the mounting hole (4a) and has interference fit.

6. The ball wear-resistant sheet according to any one of claims 1 to 3, characterized in that: The bottom surface of the cover plate (2) is provided with a plurality of protruding positioning posts (2c); the sponge layer (4) is provided with perforations (4b) corresponding one-to-one to the positioning posts (2c); the bottom plate (1) is provided with positioning holes (1a) corresponding one-to-one to the positioning posts (2c); the positioning posts (2c) are inserted into and fixed in the corresponding positioning holes (1a) after passing through the corresponding perforations (4b).

7. The ball wear-resistant sheet according to any one of claims 1 to 3, characterized in that: The top surface of the bottom plate (1) is a plane, and the bottom of the ball (3) abuts against the top surface of the bottom plate (1).

8. The ball wear-resistant sheet according to any one of claims 1 to 3, characterized in that: The thickness of the bottom plate (1) is greater than the diameter of the ball (3).

9. The ball wear-resistant sheet according to claim 6, characterized in that: The positioning column (2c) is provided with a stepped bolt hole (2d).

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