Large-friction-force spherical tooth-shaped pressing head for clamp
By designing a high-friction spherical toothed indenter, the problem of insufficient clamping force in machining fixtures was solved, achieving uniform clamping force distribution on different workpiece surfaces and improving machining accuracy and safety.
Patent Information
- Application Number
- CN202520201926.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-10
- Publication Date
- 2026-02-10
- Estimated Expiration
- 2035-02-10
AI Technical Summary
Existing machining fixtures have insufficient clamping force in steering knuckle machining, which leads to the displacement of the vibrating cutter or workpiece, affecting machining accuracy and safety. In addition, traditional pressure heads have insufficient friction on uneven surfaces, making it difficult to clamp effectively.
A high-friction spherical toothed indenter is designed with a spherical bottom surface divided into multiple clamping zones, including a central clamping zone, a first auxiliary clamping zone, a second auxiliary clamping zone, and a third auxiliary clamping zone. The tooth shape gradually increases to provide uniform clamping force and adapt to different workpiece surfaces.
It increases clamping force, reduces clamping deformation, and is suitable for flat, inclined, and curved surfaces, ensuring machining accuracy and safety, and enhancing the adaptability and stability of the fixture.
Smart Images
Figure CN223889799U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of clamping technology in machining, and in particular to a high-friction spherical toothed indenter for clamping, which can improve clamping force, reduce clamping deformation, and is suitable for effective clamping of various surfaces such as planes, inclined planes, and curved surfaces. Background Technology
[0002] In the machining workshop of a steering knuckle factory, there is a large demand for the production and processing of various steering knuckles. To efficiently produce qualified products, cutting efficiency must be increased, which usually involves generating greater cutting forces. When the clamping force of the machining fixture is insufficient to resist these forces, unacceptable vibrations or workpiece misalignment may occur. This can not only lead to defective products but also potentially cause machining accidents.
[0003] Traditional methods to improve the clamping force of machining fixtures include increasing hydraulic pressure or using larger, more efficient cylinders. However, the size of the cylinders and the structure of the pressure plate used in machining fixture design are greatly limited by the characteristics of machining equipment and steering knuckle products. This is especially true in machining fixtures completed on five-axis machining centers used in factories, where the space is very limited, making the use of larger cylinders difficult and uneconomical. Furthermore, an excessive pursuit of longitudinal clamping force can easily lead to product deformation during clamping.
[0004] The machining characteristics of a steering knuckle exist in all directions, especially the cutting force perpendicular to the clamping direction, which is very large. Therefore, under normal circumstances, the longitudinal clamping force is sufficient, but the lateral clamping force (friction) is lacking. The longitudinal clamping force is provided by the hydraulic cylinder clamping force, which is determined by the size of the hydraulic cylinder and the type of cylinder used. The lateral clamping force is static friction, mainly determined by the longitudinal clamping force and the contact surface between the pressure head and the workpiece. Figure 6 A schematic diagram is given of the hydraulic cylinder clamping force, longitudinal clamping force, and lateral clamping force.
[0005] To reduce product clamping deformation and increase lateral clamping force under limited conditions, a pressure head with a larger contact surface and coefficient of friction is needed. In the design of machining fixtures, to ensure accurate workpiece positioning and clamping, the support point and clamping point need to be on the same axis, which is determined by the positioning and clamping principle of machining fixtures. For OP10 fixtures, the support point and clamping point are usually located on the workpiece's blank surface. To ensure the positioning accuracy of the machining fixture, the design of the support point and clamping point needs to be as small as possible to reduce interference with the workpiece machining area. Typically, the diameter of these points is designed to be D6, a common size used to ensure that the contact between the machining fixture and the workpiece is both sufficiently stable and not too large to affect machining accuracy. At the same time, the clamping surface should not exceed the support surface. If the clamping surface exceeds the support surface, the workpiece may undergo unnecessary clamping deformation under clamping force, which will directly affect machining accuracy and product quality.
[0006] Common clamping head designs are mostly flat, which results in relatively low friction. When the size of the clamping surface is fixed, a planar toothed clamping head is sometimes used to increase friction. Planar toothed clamping heads improve the coefficient of friction by increasing the texture of the contact surface, thus providing a better clamping effect. However, both flat and planar toothed clamping heads are prone to localized stress concentration when clamping uneven workpiece surfaces, leading to clamping deformation and affecting machining accuracy. Although planar toothed clamping heads can increase friction, when the clamping surface size is fixed, due to potential irregularities on the workpiece surface and manufacturing errors in the clamping mechanism itself, the actual effective clamping area may be limited to a small corner of the workpiece, failing to fully utilize the advantages of the toothed design. This is especially true on inclined surfaces with large angles or curved surfaces with high curvature, where the increase in friction is not significant.
[0007] To ensure the clamping point is aligned as closely as possible with the axis of the support point and to minimize workpiece deformation caused by clamping force, spherical indenters are sometimes used. Spherical indenters can better adapt to irregularities on the workpiece surface, thus reducing clamping deformation and increasing friction to some extent. However, spherical indenters may not provide as much friction as toothed indenters, especially on inclined surfaces with large angles or curved surfaces with high curvature. The clamping effect of spherical indenters is poor because the spherical design is primarily intended to accommodate and accommodate surface irregularities rather than to increase friction. Summary of the Invention
[0008] The technical problem to be solved by this utility model is to provide a high-friction spherical toothed pressure head for clamps, which can increase friction to improve clamping force, reduce clamping deformation, and is suitable for effective clamping of various surfaces such as planes, inclined planes, and curved surfaces.
[0009] The technical solution adopted by this utility model to solve the above-mentioned technical problems is as follows: a high-friction spherical toothed pressure head for clamping, comprising a pressure head body, the bottom surface of which is spherical, characterized in that: the spherical surface is divided from the center outward into a central clamping area, a first auxiliary clamping area, a second auxiliary clamping area, and a third auxiliary clamping area; the central clamping area includes a central tooth; the first auxiliary clamping area includes multiple first auxiliary teeth, and these first auxiliary teeth are distributed around the periphery of the central tooth to form a cross-shaped structure; the second auxiliary clamping area includes multiple second auxiliary teeth, and these second auxiliary teeth are located on the corner areas of the cross-shaped structure, forming a square-shaped distribution structure together with the first auxiliary teeth; the third auxiliary clamping area includes multiple third auxiliary teeth, and these third auxiliary teeth are located on the periphery of the square-shaped distribution structure.
[0010] The spherical surface has a set radius of curvature, which can be selected according to the shape of the workpiece surface and clamping requirements to ensure that the clamping point is always located near the central axis of the support point. Preferably, the radius of curvature is 10mm to 50mm. For relatively flat workpiece surfaces, a larger radius of curvature (e.g., 30mm to 50mm) can provide a wider contact area, ensuring a uniform distribution of clamping force. For inclined surfaces with an angle of less than 8 degrees, a medium radius of curvature (e.g., 20mm to 30mm) can be used to ensure that the pressure head can adapt to the angle changes of the inclined surface and keep the clamping point close to the support point. The center axis near the support point; for curved surfaces with a large radius (e.g., a radius greater than 20mm), a larger radius of curvature (e.g., 20mm to 50mm) can be used to ensure that the indenter can fit well against the curved surface and reduce clamping deformation; for curved surfaces with a small radius of curvature (e.g., 10mm to 20mm), a smaller radius of curvature can be selected to ensure that the indenter can better adapt to the curvature changes of the curved surface; in specific implementation, the radius of curvature of the sphere can be designed to be 20mm, which can be used for clamping flat surfaces, as well as for clamping inclined surfaces with an angle of less than 8 degrees and curved surfaces with a radius greater than 20mm.
[0011] The central tooth, the first auxiliary tooth, the second auxiliary tooth, and the third auxiliary tooth form a row and column structure. A triangular notch between adjacent teeth results in each tooth having a small tip and a large base. The tip area of the central tooth, the first auxiliary tooth, the second auxiliary tooth, and the third auxiliary tooth increases sequentially. As the pressing depth increases, the central tooth first contacts the workpiece and forms an initial clamping point. Subsequently, the first, second, and third auxiliary teeth gradually participate in the contact and clamping. Because the tip area increases sequentially, the clamping force can gradually expand from the center outwards, avoiding localized stress concentration and ensuring a uniform distribution of clamping force.
[0012] The area between the third auxiliary clamping area and the edge of the sphere is divided by an edge transition region. The edge transition region acts as a buffer zone, reducing stress concentration from the third auxiliary clamping area to the edge of the sphere, thereby reducing the risk of damage to the workpiece or fixture in high-stress areas. At the same time, the presence of the edge transition region provides smoother force transmission, which helps to evenly distribute the clamping force throughout the entire sphere and improves clamping stability.
[0013] The included angle between the two opposite sides of the center tooth is 90 degrees to ensure that the center tooth can provide a stable initial clamping force when pressing into the workpiece.
[0014] Compared with the prior art, the advantages of this utility model are:
[0015] 1) The bottom surface of the pressure head body is designed as a spherical surface, which can automatically adapt to the unevenness of the workpiece surface and ensure that the clamping point is always located near the central axis of the support point. Compared with a planar pressure head, a spherical pressure head can evenly distribute the clamping force in multiple directions, reducing clamping deformation caused by excessive local pressure.
[0016] 2) This invention proposes a multi-stage tooth profile design. The spherical surface is divided sequentially from the center outwards into a central clamping area, a first auxiliary clamping area, a second auxiliary clamping area, and a third auxiliary clamping area. Because the bottom surface of the pressure head body is spherical, the tooth structure in each area has a different height. This design allows the pressure head to gradually increase the contact area at different pressing depths, thereby significantly improving the lateral clamping force. As the pressing depth increases, the central tooth first contacts the workpiece and forms an initial clamping point. Subsequently, the first, second, and third auxiliary teeth gradually participate in the contact clamping. With a constant clamping area, this gradual addition not only increases the clamping friction but also allows the clamping force to gradually expand from the center outwards, avoiding localized stress concentration and ensuring a uniform distribution of clamping force. Especially on uneven blank surfaces, it can better adapt to changes in the workpiece surface, providing a stable clamping effect.
[0017] 3) The multi-stage toothed design on the spherical surface allows this clamping head to adapt to different types of workpiece surfaces. It is primarily used for effective clamping of aluminum alloy or flat iron blanks. Due to the characteristics of its spherical surface, it can also be used for effective clamping of inclined and curved surfaces, exhibiting good versatility and adaptability. Even when the support surface is D6, it ensures that most of the clamping force remains within the support surface range, reducing clamping deformation. By adjusting the radius of curvature of the spherical surface, this clamping head can achieve optimal clamping results under different working conditions, ensuring that the clamping point is always located near the central axis of the support point, reducing clamping deformation. The multi-stage toothed design provides additional friction, ensuring stable and reliable clamping performance.
[0018] 4) This spherical toothed pressure head can be used in situations where corner cylinders or lever cylinders are used for clamping. The spherical toothed pressure head is connected to the pressure plate to position and fix the workpiece and maintain it in this state. Attached Figure Description
[0019] Figure 1 This is a schematic diagram of the spherical toothed indenter of this utility model;
[0020] Figure 2 This is an axial side view of the spherical toothed indenter of this utility model;
[0021] Figure 3 This is a schematic diagram of the spherical toothed indenter of this utility model;
[0022] Figure 4 This is a schematic diagram illustrating the application of the spherical toothed indenter of this utility model. Figure 1 ;
[0023] Figure 5 This is a schematic diagram illustrating the application of the spherical toothed indenter of this utility model. Figure 2 ;
[0024] Figure 6 This is a schematic diagram showing the clamping force of the hydraulic cylinder, the longitudinal clamping force, and the lateral clamping force. Detailed Implementation
[0025] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.
[0026] This utility model proposes a high-friction spherical toothed indenter for clamps, such as... Figure 1 , Figure 2 and Figure 3 As shown, it includes a pressure head body 1, the bottom surface of which is spherical. The spherical surface is divided into a central clamping area A, a first auxiliary clamping area B, a second auxiliary clamping area C, and a third auxiliary clamping area D from the center outwards. The central clamping area A includes a central tooth 21. The first auxiliary clamping area B includes multiple first auxiliary teeth 22, which are distributed around the central tooth 21 to form a cross-shaped structure. The second auxiliary clamping area C includes multiple second auxiliary teeth 23, which are located at the corners of the cross-shaped structure and together with the first auxiliary teeth 22 form a square-shaped distribution structure. The third auxiliary clamping area D includes multiple third auxiliary teeth 24, which are located around the square-shaped distribution structure.
[0027] Preferably, the spherical surface has a set radius of curvature SR. The radius of curvature SR can be selected according to the shape of the workpiece surface and the clamping requirements to ensure that the clamping point is always located near the central axis of the support point. Preferably, the radius of curvature SR is 10mm to 50mm. For relatively flat workpiece surfaces, a larger radius of curvature SR (such as 30mm to 50mm) can provide a wider contact area, ensuring a uniform distribution of clamping force. For inclined surfaces with an angle of less than 8 degrees, a medium radius of curvature SR (such as 20mm to 30mm) can be used to ensure that the indenter can adapt to the angle change of the inclined surface and maintain... The clamping point is close to the central axis of the support point. For curved surfaces with a large radius (e.g., a radius greater than 20mm), a larger radius of curvature SR (e.g., 20mm to 50mm) can be used to ensure that the indenter can fit the curved surface well and reduce clamping deformation. For curved surfaces with a small radius, a smaller radius of curvature SR (e.g., 10mm to 20mm) can be selected to ensure that the indenter can better adapt to the curvature changes of the curved surface. In specific implementation, the radius of curvature SR of the sphere can be designed to be 20mm, which can be used for clamping flat surfaces, as well as for clamping inclined surfaces with an angle of less than 8 degrees and curved surfaces with a radius greater than 20mm.
[0028] Further defined, the central tooth 21, the first auxiliary tooth 22, the second auxiliary tooth 23, and the third auxiliary tooth 24 form a row structure, with a triangular cutting notch 3 between adjacent teeth, making the tooth tip small and the tooth base large for each tooth. The tooth tip area of the central tooth 21, the first auxiliary tooth 22, the second auxiliary tooth 23, and the third auxiliary tooth 24 increases sequentially. As the pressing depth increases, the central tooth 21 first contacts the workpiece and forms an initial clamping point. Subsequently, the first auxiliary tooth 22, the second auxiliary tooth 23, and the third auxiliary tooth 24 gradually participate in contact clamping. Because the tooth tip area increases sequentially, the clamping force can gradually expand from the center outward, avoiding local stress concentration and ensuring uniform distribution of clamping force.
[0029] Preferably, the area between the third auxiliary clamping region D and the edge of the sphere is divided by an edge transition region E. The edge transition region E can act as a buffer zone, reducing stress concentration from the third auxiliary clamping region D to the edge of the sphere, thereby reducing the risk of damage to the workpiece or fixture in high-stress areas; at the same time, the presence of the edge transition region E can provide smoother force transmission, which helps to evenly distribute the clamping force throughout the entire sphere and improve the stability of clamping.
[0030] Preferably, the included angle between the two opposing sides 211 of the center tooth 21 is 90 degrees to ensure that the center tooth 21 can provide a stable initial clamping force when pressing into the workpiece.
[0031] This spherical toothed indenter is particularly suitable for clamping surfaces smaller than D10, such as... Figure 2As shown, the arc surface containing the spherical surface is the theoretical clamping arc surface of the indenter, and the plane containing the tooth tip of the central tooth 21 is the theoretical clamping plane of the workpiece. Due to the characteristics of the spherical tooth indenter, the maximum deviation angle that can be clamped in the theoretical clamping area of the indenter D6 is 8.6 degrees, and the height difference in the theoretical clamping area of the indenter D6 is 0.23mm (the height difference between the highest and lowest points of the tooth tip in the theoretical clamping area of D6). When the workpiece is clamped, there is only one central tooth 21 in the central clamping area A, which makes it easy to clamp. The tooth is inserted into the workpiece to form a pit. Then, the four larger first auxiliary teeth 22 in the first auxiliary clamping area B engage in contact clamping, followed by the four larger second auxiliary teeth 23 in the second auxiliary clamping area C, thereby obtaining a large frictional force. When the indentation exceeds 0.23mm and the contact clamping exceeds the second auxiliary clamping area C, twelve extra-large third auxiliary teeth 24 engage in contact clamping. The multiplied contact clamping area can effectively increase the frictional force, while preventing the teeth from being pressed too deeply into the workpiece, thus reducing tooth marks.
[0032] Figure 4 and Figure 5 A schematic diagram illustrating the application of a spherical toothed indenter is provided.
Claims
1. A high-friction spherical toothed indenter for a clamp, comprising an indenter body, wherein the bottom surface of the indenter body is spherical, characterized in that: The spherical surface is divided into a central clamping region, a first auxiliary clamping region, a second auxiliary clamping region, and a third auxiliary clamping region from the center outwards. The central clamping region includes a central tooth. The first auxiliary clamping region includes multiple first auxiliary teeth, which are distributed around the central tooth to form a cross-shaped structure. The second auxiliary clamping region includes multiple second auxiliary teeth, which are located at the corners of the cross-shaped structure and together with the first auxiliary teeth form a square-shaped distribution structure. The third auxiliary clamping region includes multiple third auxiliary teeth, which are located around the square-shaped distribution structure.
2. The high-friction spherical toothed indenter for a clamp according to claim 1, characterized in that: The sphere has a set radius of curvature.
3. The high-friction spherical toothed indenter for a clamp according to claim 1, characterized in that: The central tooth, the first auxiliary tooth, the second auxiliary tooth, and the third auxiliary tooth form a row and column structure. There is a triangular cut between two adjacent teeth so that the tooth tip of each tooth is small and the tooth base is large. The tooth tip area of the central tooth, the first auxiliary tooth, the second auxiliary tooth, and the third auxiliary tooth increases sequentially.
4. A high-friction spherical toothed indenter for a clamp according to claim 3, characterized in that: The area between the third auxiliary clamping area and the edge of the sphere is divided into an edge transition area.
5. A high-friction spherical toothed indenter for a clamp according to any one of claims 1 to 4, characterized in that: The included angle between the two opposite sides of the central tooth is 90 degrees.