Machining and clamping device for thin-wall cylindrical part

Abstract

The invention discloses a machining and clamping device for a thin-wall cylindrical part, and relates to the technical field of part machining. The machining and clamping device comprises a tool main body, a positioning sleeve, filler and a pressing cover; a positioning sleeve is arranged in the tool main body, the positioning sleeve and the tool main body are coaxially arranged, the matching surface of the tool main body and the positioning sleeve is a conical surface, the end part of the tool main body is in threaded connection with a pressing cover, and the pressing cover is used for fixing the positioning sleeve; a filling groove is formed in the inner wall of the positioning sleeve, and the filler is arranged in the filling groove; an elastic layer is arranged on the inner wall surface of the positioning sleeve. Under the condition that the positioning precision and clamping of the part are guaranteed, multi-point distributed clamping of the thin-wall cylindrical part in the full length range is achieved, it is guaranteed that the appearance of the thin-wall cylindrical part is free of clamping marks and clamping deformation, self-centering of the thin-wall cylindrical part during clamping is achieved, the clamping efficiency is improved, vibration is avoided in the machining process of the thin-wall cylindrical part, and the machining quality of the thin-wall cylindrical part is improved. And the part machining precision and quality are effectively improved.

Description

Technical Field

[0001] This invention relates to the field of parts processing technology, and in particular to a clamping device for processing thin-walled cylindrical parts. Background Technology

[0002] Thin-walled cylindrical parts are characterized by thin walls, poor rigidity, and high dimensional accuracy. They are prone to large clamping deformation and vibration during processing, which can affect the dimensional accuracy and surface quality of the product. This is especially true for cylindrical missile structures used in aerospace products, which have complex internal structures and high dimensional accuracy, with the thinnest walls reaching 1 mm and a material removal rate of over 80%. This poses a huge challenge to the processing of these parts.

[0003] Currently, these cylindrical parts are machined on CNC lathes using three-jaw soft jaws for clamping. First, the clamping length of the soft jaws in this clamping method is generally between 20mm and 50mm, which cannot achieve clamping over a longer range of parts. When the soft jaws are too long, they tend to create a flared opening after clamping, resulting in line contact between the soft jaws and the parts. This can lead to the parts not being clamped securely, and can also cause damage to the parts' shape, or even deformation. Second, because the soft jaws clamp the parts radially, no axial clamping force is applied during the clamping process. In addition, the clamping distance of the soft jaws is short. When the overhang ratio of the parts is too long, the parts are prone to axial movement when the tool is machining in the reverse direction (from left to right), and the machining process generates significant vibration, thus affecting product quality.

[0004] A search of existing technologies revealed Chinese invention patent publication number CN102886752A, which discloses a clamping device for thin-walled parts. The device includes a flange cover, a sealing ring, a pressure ring, a spacer ring, and a chuck sleeve. The flange cover is fixedly connected to the chuck sleeve. Within the hole of the chuck sleeve, the pressure ring, sealing ring, spacer ring, and sealing ring are arranged sequentially from the outside in, with the pressure ring located at one end of the flange cover. This patent utilizes the flexible deformation of the sealing ring to clamp the outer diameter of the thin-walled part; however, it suffers from the aforementioned problems.

[0005] Chinese invention patent publication number CN102581759A discloses a thin-walled machining fixture, including a positioning sleeve, a fixing sleeve, and a mandrel. The fixing sleeve is used to fully enclose and clamp the thin-walled part. This full-enclosure clamping has very high requirements for the outer circle of the part. If the outer circle of the part has a local ellipse or a certain taper, firstly, this clamping will cause the part to deform, and secondly, the fixing sleeve cannot fully fit the part. This will cause vibration during machining and damage to the surface of the part when the fixing sleeve is screwed into the thread of the positioning sleeve. Summary of the Invention

[0006] The purpose of this invention is to address the deficiencies in the existing technology by proposing a machining and clamping device for thin-walled cylindrical parts.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: A clamping device for machining thin-walled cylindrical parts includes a fixture body, a positioning sleeve, a filler, and a clamping cap. The positioning sleeve is disposed inside the fixture body and is coaxially arranged with the fixture body. The mating surface between the fixture body and the positioning sleeve is a conical surface. The end of the fixture body is threadedly connected to a clamping cap for fixing the positioning sleeve. A filling groove is formed on the inner wall of the positioning sleeve, and the filler is disposed in the filling groove. An elastic layer is provided on the inner wall surface of the positioning sleeve.

[0008] Furthermore, the tooling body has an open structure on one side and a closed structure on the other side. The clamping cover is located on the open side and is threaded with the outer wall of the tooling body. The closed side of the tooling body is provided with a flange and a boss. A connecting hole is provided on the flange. The tooling body is connected to the end face of the lathe spindle through the connecting hole. The boss is adapted to the positioning hole on the end face of the lathe spindle.

[0009] Furthermore, the inner wall of the tooling body is provided with at least one weight-reducing annular groove, which is located adjacent to the filling groove.

[0010] Furthermore, the positioning sleeve has a conical structure and a straight inner diameter; the filling groove on the positioning sleeve is an annular groove, and the filling material is flush with the height of the elastic layer.

[0011] Furthermore, the positioning sleeve is provided with multiple filling grooves; the filling material is an EPP shockproof foam block, which is embedded in the filling grooves of the positioning sleeve.

[0012] Furthermore, the elastic layer is made of nitrile rubber, and the inner diameter of the elastic layer is larger than the outer diameter of the workpiece.

[0013] Furthermore, the clamping cover has a through hole, the diameter of which is greater than the outer diameter of the workpiece but less than the maximum outer diameter of the positioning sleeve on the side away from the lathe spindle end face.

[0014] Beneficial effects

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: The machining and clamping device for thin-walled cylindrical parts of the present invention adopts a fixture body fixed on the end face of the lathe spindle and a positioning sleeve assembly. The positioning sleeve assembly is pressed to the left by the threaded engagement of the clamping cover with the fixture body, so that the elastic layer is in close contact with the workpiece. An axial force and a radial force are applied to the workpiece to clamp it. The filler between the workpiece and the positioning sleeve avoids the influence of machining vibration on the machining accuracy and quality of the workpiece. At the same time, the multi-point distributed clamping along the entire length of the workpiece greatly increases the rigidity of the machining system, avoids the influence of outer circle deformation on the clamping, realizes the self-centering of the part clamping, avoids damage to the outer circle of the workpiece caused by clamping, improves the machining accuracy and quality of the workpiece, is easy to disassemble and assemble, and greatly improves the machining efficiency. Attached Figure Description

[0016] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the embodiments of the invention to explain the invention and do not constitute a limitation thereof.

[0017] Appendix Figure 1 This is a schematic diagram of the machining and clamping device for thin-walled cylindrical parts according to the present invention; Appendix Figure 2 Right view of the main body of the tooling; Appendix Figure 3 This is a sectional view of the main body of the tooling; Appendix Figure 4 This is a sectional view of the end face structure of a lathe spindle; Appendix Figure 5 This is a sectional view of the positioning sleeve structure; Appendix Figure 6 This is a cross-sectional view of the clamping cap structure; In the diagram: 1. Lathe spindle end face; 2. Fixture body; 3. Positioning sleeve; 4. Filler; 5. Pressure cap; 6. Workpiece; 7. Socket head screw; 101. Center hole; 102. Threaded hole on lathe spindle end face; 201. Cylindrical boss; 202. Weight-reducing annular groove; 203. External thread; 204. Bottom of fixture body; 301. Elastic layer; 302. Annular groove; 501. Through hole; 502. Internal thread of pressure cap. Detailed Implementation

[0018] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0019] In the description of this invention, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0020] Reference Figures 1-6 A machining and clamping device for thin-walled cylindrical parts includes a tooling body 2, a positioning sleeve 3, a filler 4, and a clamping cover 5. The positioning sleeve 3 is disposed inside the tooling body 2 and is coaxially disposed with the tooling body 2. The mating surfaces of the tooling body 2 and the positioning sleeve 3 are conical surfaces. The end of the tooling body 2 is threadedly connected to the clamping cover 5, which is used to fix the positioning sleeve 3. A filling groove is opened on the inner wall of the positioning sleeve 3, and the filler 4 is disposed in the filling groove. An elastic layer 301 is disposed on the inner wall surface of the positioning sleeve 3.

[0021] The tooling body 2 and positioning sleeve 3 are fixed on the end face 1 of the lathe spindle. The positioning sleeve 3 is pressed to the left by the threaded engagement of the clamping cover 5 with the tooling body 2, so that the elastic layer 301 is in close contact with the workpiece 6. An axial force and a radial force are applied to the workpiece 6 to clamp it. The filler 4 between the workpiece 6 and the positioning sleeve 3 avoids the influence of machining vibration on the machining accuracy and quality of the workpiece 6. At the same time, the multi-point distributed clamping along the entire length of the workpiece 6 greatly increases the rigidity of the tooling system, avoids the influence of outer diameter deformation on the clamping, realizes the self-centering of the workpiece clamping, avoids damage to the outer diameter of the workpiece 6 due to clamping, improves the machining accuracy and quality of the workpiece 6, is easy to disassemble and assemble, and greatly improves the machining efficiency.

[0022] In other preferred embodiments, the tooling body 2 has an open structure on one side and a closed structure on the other side. The clamping cover 5 is disposed on the open side and mates with the external thread 203 on the outer wall of the tooling body 2. The closed side of the tooling body 2 is provided with a flange and a boss. A connecting hole is provided on the flange. The tooling body 2 is connected to the lathe spindle end face 1 through the connecting hole. The boss is adapted to the positioning hole of the lathe spindle end face 1.

[0023] Specifically, the inner surface of the tooling body 2 is a conical surface, the inner cavity is provided with a weight-reducing annular groove 202, the left end is a cylindrical boss 201, and the outer circle of the right end is provided with an external thread 203. The cylindrical boss 201 at the left end is matched with the center hole 101 of the lathe spindle end face 1 for positioning, ensuring that the tooling body 2 is concentric with the lathe spindle. Then, six cylindrical head hexagon socket screws 7 are used to fix it on the threaded hole 102 of the lathe spindle end face.

[0024] In other preferred embodiments, at least one weight-reducing annular groove 202 is provided on the inner wall of the tooling body 2, and the weight-reducing annular groove 202 is located adjacent to the filling groove.

[0025] In other preferred embodiments, the positioning sleeve 3 has a conical structure and an inner diameter of a straight cylinder; the filling groove on the positioning sleeve 3 is an annular groove 302, and the filler 4 is flush with the height of the elastic layer 301.

[0026] In other preferred embodiments, the positioning sleeve 3 is provided with multiple filling grooves; the filler 4 is an EPP shockproof foam block, which is embedded in the filling grooves of the positioning sleeve 3.

[0027] In other preferred embodiments, the elastic layer 301 is made of nitrile rubber, and its inner diameter is larger than the outer diameter of the workpiece 6. Specifically, the elastic layer 301 is glued to the cylindrical surface of the positioning sleeve 3, and its inner diameter is slightly larger than the outer diameter of the workpiece 6 by 1 mm, facilitating the insertion and clamping of the workpiece 6.

[0028] In other preferred embodiments, the clamping cover 5 has a through hole 501. The diameter of the through hole 501 is larger than the outer diameter of the workpiece 6 and smaller than the maximum outer diameter of the positioning sleeve 3 on the side away from the lathe spindle end face 1. The clamping cover 5 has a through hole 501 in the middle so that the workpiece 6 can be properly placed into the positioning sleeve 3. The inner hole at the left end of the clamping cover 5 has an internal thread 502, which cooperates with the external thread 203 at the right end of the tooling body 2 to press the positioning sleeve 3 to the left. This makes the outer conical surface of the positioning sleeve 3 fit tightly against the conical surface of the tooling body 2, the elastic layer 301, and the workpiece 6, applying a leftward and downward force to the workpiece 6, thereby fixing the workpiece 6 and ensuring that the workpiece 6 is concentric with the spindle.

[0029] Working principle and usage process of this invention: Workpiece 6 is placed inside fixture body 2, with its left end face as close as possible to the bottom 204 of fixture body 2. Then, by tightening the clamping cap 5, the positioning sleeve 3 is pushed forward. Due to the taper, the elastic layer 301 adheres to workpiece 6 and undergoes a certain deformation, applying a normal force towards the center of workpiece 6 to hold it in place. Simultaneously, a force is applied to the left, ensuring tight contact with the bottom surface of fixture body 2, preventing workpiece 6 from escaping to the right, thus achieving self-centering clamping of workpiece 6. After workpiece 6 is clamped, the filler 4 located between the positioning sleeve 3 and workpiece 6 deforms and comes into contact with workpiece 6, absorbing vibrations during the machining process.

[0030] In this embodiment, the multi-point distributed elastic layer 301 is used to press the workpiece 6, realizing clamping of the workpiece 6 along its entire length. This not only increases the rigidity and reliability of the processing process, but also avoids deformation and vibration of the workpiece 6 during processing. Compared with full-coverage clamping of the workpiece 6 along its entire length, this structure greatly reduces clamping deformation caused by the non-circularity of the outer circle of the workpiece 6, improves the processing accuracy and quality of the workpiece 6, and increases processing efficiency.

[0031] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A machining and clamping device for thin-walled cylindrical parts, characterized in that, The fixture includes a main body, a positioning sleeve, a filler, and a clamping cap. The positioning sleeve is disposed inside the main body and is coaxially arranged with the main body. The mating surface between the main body and the positioning sleeve is a conical surface. A clamping cap is threaded to the end of the main body and is used to fix the positioning sleeve. A filling groove is formed on the inner wall of the positioning sleeve, and the filler is disposed in the filling groove. An elastic layer is provided on the inner wall surface of the positioning sleeve.

2. The machining and clamping device for thin-walled cylindrical parts according to claim 1, characterized in that, The fixture body has an open structure on one side and a closed structure on the other side. The clamping cover is located on the open side and is threaded with the outer wall of the fixture body. The closed side of the fixture body is provided with a flange and a boss. The flange has a connecting hole. The fixture body is connected to the end face of the lathe spindle through the connecting hole. The boss is adapted to the positioning hole of the end face of the lathe spindle.

3. The machining and clamping device for thin-walled cylindrical parts according to claim 1, characterized in that, At least one weight-reducing annular groove is provided on the inner wall of the tooling body, and the weight-reducing annular groove is located adjacent to the filling groove.

4. The machining and clamping device for thin-walled cylindrical parts according to claim 1, characterized in that, The positioning sleeve has a conical structure and a straight inner diameter; the filling groove on the positioning sleeve is an annular groove, and the filling material is flush with the height of the elastic layer.

5. The machining and clamping device for thin-walled cylindrical parts according to claim 1, characterized in that, The positioning sleeve is provided with multiple filling slots; the filling material is EPP shockproof foam block, which is embedded in the filling slots of the positioning sleeve.

6. The machining and clamping device for thin-walled cylindrical parts according to claim 1, characterized in that, The elastic layer is made of nitrile rubber, and the inner diameter of the elastic layer is larger than the outer diameter of the workpiece.

7. The machining and clamping device for thin-walled cylindrical parts according to claim 1, characterized in that, The clamping cover has a through hole, the diameter of which is greater than the outer diameter of the workpiece but less than the maximum outer diameter of the positioning sleeve on the side away from the lathe spindle end face.

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