Pre-tensioning pull-down clamping device

Abstract

The utility model relates to a clamping device, in particular to a pre-tensioning pull-down clamping device, which comprises a clamping seat provided with a piston hole and a tensioning hole communicated with the piston hole; the positioning seat is arranged at the top of the tensioning hole and is provided with a positioning hole; the tensioning sleeve is movably arranged in the positioning hole and is provided with a plurality of tensioning taper holes and a plurality of tensioning grooves communicated with the tensioning taper holes; the tensioning pull rod is provided with a tensioning conical surface, the tensioning pull rod is movably inserted into the tensioning conical hole, and the tensioning conical surface abuts against the tensioning conical hole in a sliding mode; the elastic limiting assembly is movably arranged in the tensioning hole, connected with the tensioning sleeve and used for limiting the axial position of the tensioning sleeve when the workpiece is pre-tensioned; and the tensioning piston is movably arranged in the piston hole and is connected with the tensioning pull rod. According to the pre-tensioning pull-down clamping device, the tensioning sleeve does not move in the axial direction when the workpiece is preliminarily tensioned through the elastic limiting assembly, then the position change of the workpiece is avoided, meanwhile, the tensioning sleeve and the surface of the workpiece do not slide relatively, indentations are not likely to be left, and the inner circle face of the workpiece is effectively protected.

Description

Technical Field

[0001] This utility model relates to a clamping device, and more particularly to a pre-tensioned pull-down clamping device. Background Technology

[0002] To facilitate the clamping and positioning of parts during machining, hydraulic cylinders are typically used for workpiece positioning and clamping. For example, CN 220547910 U discloses a hydraulic tensioning pull-down positioning clamping device. This device uses a frustum-shaped column to facilitate the installation of the expansion sleeve structure, a piston rod to drive a pull rod up and down, upper and lower pressure blocks on the upper end of the pull rod to push the expansion sleeve structure down, and the frustum-shaped column to control the expansion sleeve structure's expansion for clamping. A return spring is installed to reset the expansion sleeve structure, and an air tightness detection module is installed to check the airtightness of the clamping position, ensuring the positioning accuracy of the clamping device. However, during use, the expansion sleeve expansion causes the workpiece to move axially, leading to changes in workpiece positioning and affecting machining. Furthermore, since the expansion sleeve can only tighten by moving axially, it still needs to move axially after initially pressing onto the workpiece, easily leaving indentations. Utility Model Content

[0003] To address the issues of workpiece positioning changes and indentations, this invention provides a pre-tensioned pull-down clamping device. The specific technical solution is as follows:

[0004] A pre-tensioning pull-down clamping device includes: a clamping seat having a piston hole and a tensioning hole communicating with the piston hole; a positioning seat having a positioning hole at the top of the tensioning hole; a tensioning sleeve having a tensioning conical hole and a tensioning groove communicating with a plurality of tensioning conical holes; a tensioning rod having a tensioning conical surface, the tensioning rod being movably inserted into the tensioning conical hole, the tensioning conical surface sliding against the tensioning conical hole; an elastic limiting component having a movable position in the tensioning hole and connected to the tensioning sleeve, used to limit the axial position of the tensioning sleeve when pre-tensioning the workpiece; and a tensioning piston having a movable position in the piston hole and connected to the tensioning rod.

[0005] Preferably, the elastic limiting component includes a spring, which is movably sleeved on the tensioning rod, and its two ends are respectively connected to the tensioning hole and the tensioning sleeve.

[0006] Furthermore, the elastic limiting component also includes: a gasket, the gasket being movably inserted into the tensioning rod, and the gasket being respectively disposed between the bottom of the spring and the tensioning hole and between the spring and the tensioning sleeve.

[0007] Preferably, the positioning seat is further provided with a limiting groove communicating with the positioning hole, and the tensioning sleeve is provided with a limiting ring, which is movably inserted into the limiting groove.

[0008] Preferably, the tensioning grooves are arranged in a ring array.

[0009] Preferably, the tensioning rod includes a tensioning rod, a limiting rod, and a connecting rod arranged in sequence. The tensioning rod is provided with a tensioning conical surface. The limiting rod is movably inserted into the elastic limiting assembly. The connecting rod is connected to the tensioning piston.

[0010] Furthermore, the top of the tensioning rod is also provided with a tightening hole for inserting a tool.

[0011] Furthermore, the tensioning piston is provided with a limiting hole and a connecting screw hole located at the bottom of the limiting hole, the limiting rod is inserted into the limiting hole, and the connecting screw hole is connected to the connecting rod.

[0012] Preferably, it also includes an elastic adhesive, which is disposed within the tensioning groove.

[0013] Compared with the prior art, the present invention has the following beneficial effects:

[0014] The present invention provides a pre-tensioning pull-down clamping device that, through the elastic limiting component, prevents the tensioning sleeve from moving axially during the initial tensioning of the workpiece, thereby avoiding changes in the position of the workpiece. At the same time, the tensioning sleeve and the workpiece surface will not slide relative to each other, making it less likely to leave indentations and effectively protecting the inner circular surface of the workpiece. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the structure of this application;

[0016] Figure 2 This is a cross-sectional view of this application;

[0017] Figure 3 This is a schematic diagram of the tensioning sleeve structure;

[0018] Figure 4 This is a top view of the tensioning sleeve;

[0019] Figure 5 This is a schematic diagram of the tensioning rod.

[0020] Figure 6 This is a front view of the tension rod;

[0021] Figure 7 This is a schematic diagram of the tensioning piston structure;

[0022] Figure 8 This is a schematic diagram of the positioning seat. Detailed Implementation

[0023] The present invention will now be further described with reference to the accompanying drawings.

[0024] like Figures 1 to 8 As shown, a pre-tensioned pull-down clamping device includes a clamping seat 1, a positioning seat 4, a tensioning sleeve 2, a tensioning rod 3, an elastic limiting component 5, and a tensioning piston 7. The clamping seat 1 has a piston hole 11 at its bottom and a tensioning hole 13 at its top. The tensioning hole 13 is coaxially aligned with the piston hole 11 and communicates with it through a connecting hole. The clamping seat 1 also has a first oil hole and a second oil hole communicating with the top and bottom of the piston hole 11, respectively. The tensioning piston 7 is movably inserted into the piston hole 11, and its piston rod is movably inserted into the connecting hole. The piston rod is connected to the tensioning rod 3, and the top of the tensioning rod 3 has a tensioning conical surface 30, making the top of the tensioning rod 3 frustum-shaped. The positioning seat 4 is installed on the top of the tensioning hole 13, and the top of the positioning seat 4 serves as a support surface for the workpiece. The positioning seat 4 has a positioning hole 41, which is coaxially aligned with the tensioning piston 7. The tensioning sleeve 2 has multiple tensioning grooves 23 arranged in a ring array. The number of tensioning grooves 23 can be set as needed, and can be set to three. The tensioning grooves 23 are through grooves. The tensioning sleeve 2 also has a tensioning conical hole 22, which communicates with the tensioning grooves 23. The tensioning grooves 23 divide the tensioning sleeve 2 into three tensioning blocks 21. The tensioning sleeve 2 is movably inserted into the positioning hole 41. The tensioning conical hole 22 matches the tensioning conical surface 30, and the tensioning conical hole 22 slides against the tensioning conical surface 30 to form an inclined surface drive. The elastic limiting component 5 is movably installed in the tensioning hole 13 and connected to the bottom of the tensioning sleeve 2. The elastic limiting component 5 is used to limit the axial position of the tensioning sleeve 2 when pre-tensioning the workpiece.

[0025] The workpiece is clamped and its inner hole is inserted into the tensioning sleeve 2. The bottom of the workpiece rests against the top of the positioning seat 4. The top of the positioning seat 4 supports the workpiece and achieves axial positioning of the workpiece. Then, oil enters through the first oil hole, and the hydraulic oil pushes the tensioning piston 7 to move downward. The tensioning piston 7 drives the tensioning rod 3 to move downward. The tensioning cone surface 30 pushes the tensioning sleeve 2 to expand its diameter through the tensioning cone hole 22, which means it pushes the tensioning block 21 to move radially. At this time, because the elastic limiting component 5 will hold the tensioning sleeve 2, the tensioning sleeve 2 will not move downward until the tensioning sleeve 2 is pressed against the inner hole of the workpiece, achieving positioning during pre-tensioning of the workpiece. This ensures that neither the workpiece nor the tensioning sleeve 2 will move axially during pre-tensioning, achieving reliable positioning. Then, the tensioning sleeve 2 moves the workpiece towards the top of the positioning seat 4, pressing the workpiece against the support surface at the top of the positioning seat 4. During this process, the tensioning sleeve 2 will also have a small axial movement in the inner hole of the workpiece, but it is much smaller than the movement length of the tensioning sleeve 2 in the inner hole of the workpiece in the prior art. Therefore, the tensioning sleeve 2 is not likely to leave indentations in the inner hole of the workpiece. When the workpiece is released, oil enters through the second oil hole, the tensioning piston 7 moves upward, and the tensioning rod 3 moves upward with the tensioning piston 7. The tensioning cone surface 30 separates from the tensioning cone hole 22, and the tensioning block 21 is in a free state. At this time, the workpiece can be removed.

[0026] Since the workpiece is basically tightened during the pre-tightening stage, the axial movement distance of the tensioning sleeve 2 relative to the workpiece can be effectively reduced during the entire tightening process, which can effectively improve the reliability of positioning and avoid indentation on the inner hole of the workpiece.

[0027] The elastic limiting component 5 includes a spring 51, which is movably sleeved on the tensioning rod 3. The two ends of the spring 51 abut against the bottom of the tensioning hole 13 and the bottom of the tensioning sleeve 2, respectively. The spring 51 has a simple structure and low cost. The spring 51 can be a cylindrical compression spring or a disc spring. To facilitate the fixing of the spring 51, the elastic limiting component 5 also includes two washers 52. Each washer 52 is annular and movably inserted into the tensioning rod 3, located at both ends of the spring 51. The washers 52 also abut against the bottom of the tensioning hole 13 and the bottom of the tensioning sleeve 2, respectively.

[0028] To limit the axial movement of the tensioning sleeve 2, a limiting groove 42 is provided at the bottom of the positioning seat 4. The limiting groove 42 communicates with the positioning hole 41 and is a circular groove. A limiting ring 24 is provided at the bottom of the tensioning sleeve 2. The limiting ring 24 is movably inserted into the limiting groove 42. The thickness of the limiting ring 24 is close to the depth of the limiting groove 42, which can prevent the tensioning sleeve 2 from moving freely upward along the axis within the positioning hole 41.

[0029] To facilitate the processing and assembly of the tensioning rod 3, the tensioning rod 3 includes a tensioning rod 31, a limiting rod 32, and a connecting rod 33 arranged sequentially. The diameters of the tensioning rod 31, the limiting rod 32, and the connecting rod 33 decrease sequentially, forming a stepped shaft. The tensioning rod 31 is provided with a tensioning conical surface 30, which makes the tensioning rod 31 form a frustum shape. The limiting rod 32 is movably inserted into the elastic limiting assembly 5, and the connecting rod 33 is connected to the tensioning piston 7.

[0030] To facilitate the axial positioning of the tensioning rod 3, the top of the tensioning piston 7 is provided with a limiting hole 71 and a connecting screw hole 72 from top to bottom. The limiting hole 71 and the connecting screw hole 72 are coaxially aligned and communicate with each other. The limiting hole 71 matches the limiting rod 32, which is inserted into the limiting hole 71. The shoulder of the limiting rod 32 abuts against the bottom of the limiting hole 71, thus achieving axial positioning of the limiting rod 32. The outer surface of the connecting rod 33 is provided with an external thread, which connects to the connecting screw hole 72, thus connecting the tensioning rod 3 and the tensioning piston 7.

[0031] To facilitate the installation of the tensioning rod 3, the top of the tensioning rod 31 is also provided with a tightening hole 34 for inserting tools. The tightening hole 34 can be a conventional hexagonal hole, flat hole, cross hole, etc.

[0032] To prevent foreign objects from entering the tension groove 23, an elastic adhesive is provided inside the tension groove 23. The elastic adhesive can not only seal the tension groove 23, but also not affect the contraction and expansion of the tension groove 23, thus not affecting the tension of the workpiece, and can also effectively protect the tension cone surface 30 and the tension cone hole 22.

[0033] The disc spring has a certain pre-compression amount at the initial clamping stage to prevent axial movement of the tensioning sleeve during the initial operation, resulting in a compact overall structure.

[0034] The technical principles of this utility model have been described above with reference to specific embodiments. These descriptions are merely for explaining the principles of this utility model and should not be construed as limiting the scope of protection of this utility model in any way. Based on this explanation, those skilled in the art can readily conceive of other specific embodiments of this utility model without inventive effort, and these embodiments will all fall within the protection scope of the claims of this utility model.

Claims

1. A pre-tensioned pull-down clamping device, characterized in that, include: The clamping seat (1) is provided with a piston hole (11) and a tensioning hole (13) communicating with the piston hole (11); A positioning seat (4) is provided on the top of the tensioning hole (13) and has a positioning hole (41); The tensioning sleeve (2) is movably disposed in the positioning hole (41) and is provided with a tensioning cone hole (22) and a tensioning groove (23) communicating with a plurality of the tensioning cone holes (22); The tensioning rod (3) is provided with a tensioning cone surface (30). The tensioning rod (3) is movably inserted into the tensioning cone hole (22), and the tensioning cone surface (30) slides against the tensioning cone hole (22). The elastic limiting component (5) is movably disposed in the tensioning hole (13) and connected to the tensioning sleeve (2) to limit the axial position of the tensioning sleeve (2) when pre-tensioning the workpiece; as well as The tension piston (7) is movably disposed within the piston hole (11) and connected to the tensioning rod (3).

2. The pre-tensioning pull-down clamping device according to claim 1, characterized in that, The elastic limiting component (5) includes a spring (51), which is movably sleeved on the tensioning rod (3) and its two ends are respectively connected to the tensioning hole (13) and the tensioning sleeve (2).

3. The pre-tensioning pull-down clamping device according to claim 2, characterized in that, The elastic limiting component (5) further includes: a gasket (52), which is movably inserted into the tensioning rod (3), and the gasket (52) is respectively disposed between the bottom of the spring (51) and the tensioning hole (13) and between the spring (51) and the tensioning sleeve (2).

4. The pre-tensioning pull-down clamping device according to claim 1, characterized in that, The positioning seat (4) is also provided with a limiting groove (42) communicating with the positioning hole (41), and the tensioning sleeve (2) is provided with a limiting ring (24), which is movably inserted into the limiting groove (42).

5. The pre-tensioning pull-down clamping device according to claim 1, characterized in that, The tensioning grooves (23) are arranged in a ring array.

6. The pre-tensioned pull-down clamping device according to claim 1, characterized in that, The tensioning rod (3) includes a tensioning rod (31), a limiting rod (32) and a connecting rod (33) arranged in sequence. The tensioning rod (31) is provided with a tensioning cone surface (30). The limiting rod (32) is movably inserted into the elastic limiting assembly (5). The connecting rod (33) is connected to the tensioning piston (7).

7. The pre-tensioning pull-down clamping device according to claim 6, characterized in that, The top of the tensioning rod (31) is also provided with a tightening hole (34) for inserting a tool.

8. The pre-tensioning pull-down clamping device according to claim 6, characterized in that, The tensioning piston (7) is provided with a limiting hole (71) and a connecting screw hole (72) located at the bottom of the limiting hole (71). The limiting rod (32) is inserted into the limiting hole (71), and the connecting screw hole (72) is connected to the connecting rod (33).

9. The pre-tensioning pull-down clamping device according to claim 1, characterized in that, It also includes an elastic adhesive, which is disposed in the tensioning groove (23).

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