Machining clamp applied to sleeve parts
By combining a double-tapered mandrel and an expansion collet, the problems of insufficient precision and deformation in the machining fixtures for sleeve-type tungsten steel parts are solved, enabling high-precision positioning and machining of sleeve-type parts, and meeting the requirements for high coaxiality and perpendicularity.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- KUNSHAN DONG DACHANGYING NEW MATERIALS TECHNOLOGY CO LTD
- Filing Date
- 2025-05-28
- Publication Date
- 2026-04-28
AI Technical Summary
Existing machining fixtures for sleeve-type tungsten carbide parts suffer from insufficient precision, easy deformation during clamping, and cumbersome operation, making it difficult to meet the requirements for high coaxiality and perpendicularity.
The combination structure of double-tapered mandrel and expansion collet is adopted. The expansion collet's inner wall is in contact with the tapered surface and moves axially under the action of the locking element, so as to achieve uniform tension of sleeve-type parts. Combined with the high-precision ground center hole, the positioning accuracy is guaranteed, and the requirements of coaxiality of inner and outer diameters and perpendicularity of end face are met.
It achieves high-precision clamping, avoids damage to parts, ensures the coaxiality of the inner and outer diameters and the perpendicularity of the end faces of sleeve-type parts, and improves machining accuracy and stability.
Smart Images
Figure CN224169546U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of tooling and fixture technology, and in particular to a machining fixture for sleeve-type parts. Background Technology
[0002] Tungsten carbide sleeve-type parts typically require extremely high dimensional accuracy and geometric tolerances, especially the coaxiality of the inner and outer diameters and the perpendicularity of the end face to the inner diameter. Traditionally, the following clamping method is used when machining such parts:
[0003] Three-jaw chuck clamping has low repeatability (usually ≥0.02mm) and is prone to deformation of thin-walled sleeves during clamping, making it difficult to meet the requirements for high coaxiality and perpendicularity.
[0004] Elastic collets or spring collets offer higher precision than three-jaw chucks, but their limited expansion capacity makes them less adaptable to parts with different inner diameters. Furthermore, prolonged use can lead to uneven clamping force due to elastic failure.
[0005] The mandrel positioning uses interference fit or cold pressing clamping, which has high positioning accuracy, but is inconvenient to install and remove, and can easily scratch the inner hole surface of the parts.
[0006] Liquid plastic clamps utilize the fluidity of liquid plastic to achieve uniform expansion and tightening, but their structure is complex, adjustment is difficult, and the plastic is prone to aging, affecting long-term stability.
[0007] The existing clamping methods have problems such as insufficient accuracy, easy deformation during clamping, and cumbersome operation. Therefore, this utility model develops a machining fixture for sleeve-type parts. Utility Model Content
[0008] The purpose of this invention is to provide a machining fixture for sleeve-type parts, so as to solve the problem that the machining fixture in the prior art has limited clamping capacity, resulting in low machining accuracy and easy damage to the parts.
[0009] The technical solution of this utility model is: a machining fixture for sleeve-type parts, comprising:
[0010] A double-tapered mandrel, wherein the double-tapered mandrel has a set of symmetrically arranged tapered surfaces, and the large-diameter ends of the set of tapered surfaces are arranged opposite each other;
[0011] The expansion collets are arranged in pairs, with the inner walls of each pair of expansion collets respectively conforming to a set of conical surfaces, and the outer walls being constructed as positioning surfaces.
[0012] A locking element acts on the expansion collet, pushing the expansion collet to move axially and be positioned, and adjusting the radial dimension of the positioning surface.
[0013] Preferably, the double-tapered mandrel has an integral structure, including a connecting section in the middle, tapered sections on both sides of the connecting section, and a shaft body connected to the tapered sections; the outer wall of the tapered section is configured as the tapered surface; the outer diameter of the connecting section is larger than the outer diameter of the shaft body.
[0014] Preferably, the axial dimension of the tapered segment is larger than the axial dimension of the expansion collet.
[0015] Preferably, the outer wall of the shaft body is threaded, the locking member is threadedly connected to the shaft body, and always abuts against the end face of the expansion collet.
[0016] Preferably, the locking component includes a clamping nut and a clamping washer; the clamping nut is threadedly connected to the shaft body, and the clamping washer is located between the clamping nut and the expansion collet, and is always pressed against the end face of the expansion collet by the action of the clamping nut.
[0017] Preferably, the inner diameter of the clamping pad is larger than the outer diameter of the shaft body.
[0018] Preferably, the parallelism of the two end faces of the clamping pad along the axial direction is less than 0.002 mm.
[0019] Preferably, the double-tapered mandrel has a ground-formed center hole on both end faces along the axial direction for clamping the center; the coaxiality between the tapered surface and the reference center is less than 0.002 mm.
[0020] Preferably, in the clamping state, the axial dimension between the outer end faces of the pair of expansion collets is smaller than the axial dimension of the sleeve-type part to be processed.
[0021] Compared with the prior art, the advantages of this utility model are:
[0022] (1) Applied to the processing of sleeve-type tungsten steel parts, the inner wall of the expansion collet fits with the conical surface and can move axially under the action of the locking element. In the clamping state, the outer radial direction of the expansion collet expands evenly, which can realize the clamping of sleeve-type parts. The clamping accuracy is high and it will not damage the parts.
[0023] (2) The double taper mandrel has a center hole formed by high precision grinding on both sides of the axial direction for the center to be clamped, thereby ensuring that the coaxiality requirement of the inner and outer diameters of the sleeve-type parts can be effectively guaranteed under the condition of high positioning accuracy, and the perpendicularity requirement of the end face relative to the inner diameter can be guaranteed. Attached Figure Description
[0024] The present invention will be further described below with reference to the accompanying drawings and embodiments:
[0025] Figure 1 This is a cross-sectional view of the machining fixture described in this utility model;
[0026] Figure 2 This is a cross-sectional view of the machining fixture described in this utility model in another application state;
[0027] Figure 3 This is a cross-sectional view of the machining fixture described in this utility model, which clamps a sleeve-type part.
[0028] Among them: 1. Double taper mandrel, 11. Connecting section, 12. Tapered section, 121. Tapered surface, 13. Shaft body, 14. Center hole;
[0029] 2. Expansion collet; 21. Positioning surface;
[0030] 3. Locking components; 31. Compression nut; 32. Compression washer;
[0031] 4. Sleeve-type parts, 41. Using a dial indicator to calibrate the position. Detailed Implementation
[0032] The present invention will be further described in detail below with reference to specific embodiments:
[0033] like Figure 1 As shown, a machining fixture for sleeve-type parts includes a double-tapered mandrel 1, an expansion collet 2, and a locking element 3.
[0034] The double-tapered mandrel 1 has a set of symmetrically arranged tapered surfaces 121, with the larger diameter ends of the tapered surfaces 121 facing each other. Specifically, the double-tapered mandrel 1 is an integral structure, including a connecting section 11 in the middle, tapered sections 12 on both sides of the connecting section 11, and a shaft body 13 connected to the tapered sections 12; the outer wall of the tapered section 12 is configured as a tapered surface 121; the outer diameter of the connecting section 11 is larger than the outer diameter of the shaft body 13.
[0035] The double-tapered mandrel 1 has a high-precision ground center hole 14 on both end faces along the axial direction for clamping the center. The coaxiality between the tapered surface 121 and the reference of the center is less than 0.002 mm.
[0036] The expansion collets 2 are arranged in pairs, each pair having a tapered inner hole. The inner walls of each collet 2 are respectively fitted with a set of tapered surfaces 121, and the outer wall is constructed as a positioning surface 21. In the clamped state, the positioning surface 21 is used to fit against the inner wall of the sleeve-like part 4, achieving clamping and positioning of the sleeve-like part 4. The inner and outer wall surfaces of the expansion collets 2 are coaxial, and the two end faces along the axial direction are perpendicular to the radial direction. In one embodiment, to ensure stability, the inner wall surface of the expansion collets 2 can be fully fitted against the tapered surface 121, combined with... Figure 1As shown, the axial dimension L1 of the conical segment 12 is larger than the axial dimension L2 of the expansion collet 2. In this case, the expansion collet 2 can always move fully against the conical surface 121, meaning the expansion collet 2 always moves within the dimension space corresponding to L1. Of course, under the same structure, to improve applicability, the expansion collet 2 may not completely conform to the conical surface 121, i.e. Figure 2 As shown, as long as there is a contact between the inner wall surface of the expansion collet 2 and the conical surface 121, the expansion collet 2 can act on sleeve-type parts 4 with larger inner diameters.
[0037] Of course, in other embodiments, the axial dimension of the tapered segment 12 can be less than or equal to the axial dimension of the expansion collet 2. In this case, the inner wall surface of the expansion collet 2 and the tapered surface 121 are partially in contact, but this has a certain impact on the stability and accuracy of the structure. Therefore, in practical applications, the axial dimension of the tapered segment 12 can be greater than the axial dimension of the expansion collet 2.
[0038] The locking element 3 acts on the expansion collet 2, pushing the expansion collet 2 to move axially and position it, adjusting the radial dimension of the positioning surface 21. The outer wall of the shaft body 13 is threaded, and the locking element 3 is threadedly connected to the shaft body 13 and always abuts against the end face of the expansion collet 2. To ensure accuracy, the outer wall of the shaft body 13 is made of fine thread.
[0039] In this embodiment, the locking component 3 includes a clamping nut 31 and a clamping washer 32; the clamping nut 31 is a fine-thread nut and is threadedly connected to the shaft body 13; the clamping washer 32 is located between the clamping nut 31 and the expansion collet 2, and is always pressed against the end face of the expansion collet 2 by the action of the clamping nut 31.
[0040] The inner diameter of the clamping pad 32 is larger than the outer diameter of the shaft body 13, which can accommodate the axial displacement adjustment of the expansion collet 2 and ensure that the end of the clamping pad 32 can abut against the end face of the expansion collet 2 in any axial position, without being stopped by the conical surface 121.
[0041] The parallelism of the two end faces of the clamping shim 32 along the axial direction is less than 0.002 mm, which is also used to ensure clamping accuracy.
[0042] like Figure 3 As shown, in the clamping state, the axial dimension between the outer end faces of a pair of expansion collets 2 is smaller than the axial dimension of the sleeve-type part 4 to be processed, which is used to facilitate dial indicator calibration. The positions exposed at both ends of the sleeve-type part 4 relative to the expansion collets 2 are defined as the dial indicator calibration positions 41.
[0043] Based on the disclosure of the above structure, the specific clamping method is as follows:
[0044] S1. Place the expansion collet 2 and the clamping pad 32 on the double taper spindle 1, and lock the clamping nut 31 onto the shaft body 13. At this time, the clamping nut 31 is in a non-clamped state, that is, the expansion collet 2 is not opened.
[0045] S2. Place the sleeve-type part 4 on the outer diameter of the expansion collet 2, and make the distance between the two ends of the sleeve-type part 4 and the expansion collet 2 the same, so as to facilitate the dial indicator calibration.
[0046] S3. Tighten the clamping nuts 31 at both ends, tighten the clamping pads 32, push the inner wall of the expansion collet 2 to fit against the conical surface 121, so that the outer radial direction of the expansion collet 2 expands evenly around the periphery, and supports the sleeve-like parts 4. At this time, the outer diameter of the positioning surface 21 is enlarged and fits against the inner wall of the sleeve-like parts 4.
[0047] S4. Use a dial indicator to calibrate the inner holes on both sides of the sleeve-type part 4;
[0048] S5. Mount the entire structure on the center of a high-precision cylindrical grinding machine, positioning the center at the center hole 14. Simultaneously machine the outer diameter and two end faces of the sleeve-type part 4 to ensure coaxiality and perpendicularity requirements. The final machined product can meet the coaxiality requirement of 0.01mm between the inner and outer diameters and the perpendicularity requirement of 0.005mm between the two end faces and the inner diameter.
[0049] The above embodiments are only for illustrating the technical concept and features of this utility model, and are intended to enable those skilled in the art to understand the content of this utility model and implement it accordingly. They should not be construed as limiting the scope of protection of this utility model. It is obvious to those skilled in the art that this utility model is not limited to the details of the above exemplary embodiments, and that it can be implemented in other specific forms without departing from the spirit or basic characteristics of this utility model. Therefore, the embodiments should be considered exemplary and non-limiting in all respects. The scope of this utility model is defined by the appended claims rather than the foregoing description, and therefore, all changes falling within the meaning and scope of the equivalents of the claims are intended to be included within this utility model.
Claims
1. A machining fixture for sleeve-type parts, characterized in that, include: A double-tapered mandrel (1) has a set of symmetrically arranged tapered surfaces (121) on it, with the large-diameter ends of the set of tapered surfaces (121) arranged opposite each other; The expansion collets (2) are arranged in pairs, with the inner walls of each pair of expansion collets (2) respectively attached to a set of conical surfaces (121), and the outer walls are constructed as positioning surfaces (21). The locking element (3) acts on the expansion collet (2), pushing the expansion collet (2) to move axially and be positioned, and adjusting the radial dimension of the positioning surface (21).
2. The machining fixture for sleeve-type parts according to claim 1, characterized in that: The double-tapered mandrel (1) has an integral structure, including a connecting section (11) in the middle, tapered sections (12) on both sides of the connecting section (11), and a shaft body (13) connected to the tapered sections (12); the outer wall of the tapered section (12) is configured as the tapered surface (121); the outer diameter of the connecting section (11) is larger than the outer diameter of the shaft body (13).
3. The machining fixture for sleeve-type parts according to claim 2, characterized in that: The axial dimension of the tapered segment (12) is greater than the axial dimension of the expansion collet (2).
4. The machining fixture for sleeve-type parts according to claim 2, characterized in that: The outer wall of the shaft body (13) is threaded, and the locking member (3) is threadedly connected to the shaft body (13) and always abuts against the end face of the expansion collet (2).
5. The machining fixture for sleeve-type parts according to claim 4, characterized in that: The locking component (3) includes a clamping nut (31) and a clamping washer (32); the clamping nut (31) is threadedly connected to the shaft body (13), and the clamping washer (32) is located between the clamping nut (31) and the expansion collet (2), and is always pressed against the end face of the expansion collet (2) by the action of the clamping nut (31).
6. The machining fixture for sleeve-type parts according to claim 5, characterized in that: The inner diameter of the clamping pad (32) is larger than the outer diameter of the shaft body (13).
7. The machining fixture for sleeve-type parts according to claim 5, characterized in that: The parallelism of the two end faces of the compression pad (32) along the axial direction is less than 0.002 mm.
8. The machining fixture for sleeve-type parts according to claim 1, characterized in that: The double-tapered mandrel (1) has a ground-formed center hole (14) on both end faces along the axial direction for clamping the center; the coaxiality between the tapered surface (121) and the reference center is less than 0.002 mm.
9. The machining fixture for sleeve-type parts according to any one of claims 1-8, characterized in that: In the clamping state, the axial dimension between the outer end faces of the pair of expansion collets (2) is smaller than the axial dimension of the sleeve-type part (4) to be processed.