A clamping fixture for deep hole processing of thin-walled workpieces

Abstract

The present invention relates to a clamping jig for deep hole processing of thin-walled workpieces. The clamping jig comprises a first positioning seat fixedly connected to a machine tool spindle, a second positioning seat docked with a rotating shaft of an oiler, a first fastening mechanism located on the side where the first positioning seat is located and used to fix one end of the workpiece relative to the first positioning seat, and a second fastening mechanism located on the side where the second positioning seat is located and used to fix the other end of the workpiece relative to the second positioning seat; and when the workpiece is clamped on the clamping jig, the workpiece abuts between the first positioning seat and the second positioning seat; the clamping jig for deep hole processing of thin-walled workpieces of the present invention clamps the workpiece in a double-locking manner at both ends, so that the workpiece has little deformation and high positioning accuracy, and the clamping does not generate axial force on the workpiece, thus avoiding bending and deformation of the workpiece, which is beneficial to the stability of the workpiece processing accuracy.

Description

Technical Field

[0001] The invention relates to a clamping jig for deep hole processing of thin-walled workpieces. Background Art

[0002] Deep hole boring and drilling machines are used to process deep holes with a hole diameter ratio (D / L) of 1:6 or more, such as deep holes in parts such as gun barrels, cannon barrels and machine tool spindles. There are general deep hole drilling machines, special deep hole drilling machines and those modified from ordinary lathes. In order to facilitate cooling and chip removal, the layout of deep hole drilling machines is horizontal, that is, the workpiece to be processed (mainly long rods) lies horizontally and is fixed on the machine tool. Under normal circumstances, when deep hole boring and drilling machines are processed, it is mainly the workpiece that rotates through the spindle, not the tool (drill bit). For workpieces with higher wall thickness after drilling, double-sided taper disks (female center sleeves) are usually used for automatic centering, that is, the workpiece is supported and fixed from both ends of the workpiece by the taper disks on both sides. Compared with the chuck, this fixing method has higher concentricity at both ends of the workpiece, higher positioning accuracy, and smaller repeatability error. It is an efficient and reliable clamping method. However, for workpieces with low wall thickness after processing, or workpieces that are easy to deform and have thin wall thickness before processing, if the above clamping method is adopted, the workpiece to be processed will be subjected to large axial force due to its low strength when subjected to resistance at both ends, and it is very easy to bend and deform. In addition, due to the heat of the workpiece during the processing, thermal deformation and elongation will occur, which will further increase the axial force on the workpiece, affect the processing accuracy of the workpiece, and even cause the workpiece to be deformed and scrapped. Summary of the invention

[0003] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide a clamping fixture for deep hole processing of thin-walled workpieces.

[0004] In order to solve the above technical problems, the technical solution adopted by the present invention is as follows:

[0005] A clamping fixture for deep hole processing of thin-walled workpieces, the clamping fixture includes a first positioning seat fixedly connected to a machine tool spindle, a second positioning seat docked with a rotating shaft of an oiler, a first fastening mechanism located on the side where the first positioning seat is located and used to fix one end of the workpiece relative to the first positioning seat, and a second fastening mechanism located on the side where the second positioning seat is located and used to fix the other end of the workpiece relative to the second positioning seat; and when the workpiece is clamped on the clamping fixture, the workpiece abuts between the first positioning seat and the second positioning seat.

[0006] Preferably, the clamping fixture further comprises a buffer mechanism for providing a buffer force to the workpiece axially when the workpiece is clamped on the clamping fixture.

[0007] Preferably, the buffer mechanism comprises an elastic buffer pad provided on an end surface of the second positioning seat close to the first positioning seat.

[0008] Preferably, the first fastening mechanism comprises an elastic sleeve fixedly connected to the first positioning seat and a tightening mechanism for tightening the elastic sleeve. When the tightening mechanism tightens the elastic sleeve, the end of the workpiece can be fixed on the inner circumference of the elastic sleeve.

[0009] Preferably, the elastic sleeve has a connecting portion fixedly connected to the first positioning seat and a clamping claw portion integrally provided with the connecting portion for clamping the workpiece.

[0010] Preferably, the tightening mechanism includes a tightening sleeve movably arranged along the axial direction of the workpiece, the inner circumference of the tightening sleeve is formed with a first conical inclined surface, and the outer circumference of the clamping jaw part is formed with a second conical inclined surface arranged to cooperate with the first conical inclined surface. When the tightening sleeve moves, the tightening sleeve can press the first conical inclined surface against the second conical inclined surface to make the inner circumference of the clamping jaw part fit closely against the workpiece and clamp the workpiece.

[0011] Preferably, the tightening mechanism further comprises a driver for driving the tightening sleeve to move axially along the workpiece.

[0012] Preferably, the second fastening mechanism is arranged symmetrically to the first fastening mechanism.

[0013] Preferably, the elastic buffer pad is made of polyurethane

[0014] Preferably, the inner edge of the opening of the clamping jaw portion is chamfered.

[0015] Due to the implementation of the above technical solution, the present invention has the following advantages compared with the prior art:

[0016] The clamping fixture for deep hole processing of thin-walled workpieces of the present invention clamps the workpiece in a double-locking manner at both ends, resulting in small deformation of the workpiece and high positioning accuracy. The clamping does not generate axial force on the workpiece, thus avoiding bending and deformation of the workpiece, which is beneficial to the stability of the workpiece processing accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the cross-sectional structure of the clamping fixture of the present invention;

[0018] Wherein: 100, workpiece; 10, first positioning seat; 20, second positioning seat; 30, elastic buffer pad; 31, elastic clamping sleeve; 32, tightening sleeve. DETAILED DESCRIPTION

[0019] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0020] like Figure 1As shown, a clamping fixture for deep hole processing of a thin-walled workpiece 100 is shown. The clamping fixture includes a first locating seat 10 fixedly connected to the spindle of a machine tool, a second locating seat 20 docked with the rotating shaft of an oiler, a first fastening mechanism located on the side of the first locating seat 10 for fixing one end of the workpiece 100 relative to the first locating seat 10, and a second fastening mechanism located on the side of the second locating seat 20 for fixing the other end of the workpiece 100 relative to the second locating seat 20; and when the workpiece 100 is clamped on the clamping fixture, the workpiece 100 is in contact between the first locating seat 10 and the second locating seat 20.

[0021] In this example, the clamping fixture also includes a buffer mechanism that provides a buffer force axially to the workpiece 100 when the workpiece 100 is clamped on the clamping fixture. The buffer mechanism mainly includes an elastic buffer pad 30 provided on an end surface of the second positioning seat 20 close to the first positioning seat 10; the elastic buffer pad 30 is made of polyurethane.

[0022] In addition, the first fastening mechanism includes an elastic sleeve 31 fixedly connected to the first positioning seat 10, and a tightening mechanism for tightening the elastic sleeve 31. The elastic sleeve 31 has a connection portion fixedly connected to the first positioning seat 10 and a clamping jaw portion integrally provided with the connection portion for clamping the workpiece 100 (the inner edge of the opening of the clamping jaw portion is provided with a chamfer, and the chamfer can guide the workpiece 100, so as to facilitate the end of the workpiece 100 to enter the inner periphery of the clamping jaw portion). The tightening mechanism includes a tightening sleeve 32 movably arranged along the axial direction of the workpiece 100, and a driver driving the tightening sleeve 32 to move along the axial direction of the workpiece 100. The inner periphery of the tightening sleeve 32 is formed with a first conical inclined surface, and the outer periphery of the clamping jaw portion is formed with a second conical inclined surface arranged in cooperation with the first conical inclined surface. When the tightening sleeve 32 moves, the tightening sleeve 32 can make the inner periphery of the clamping jaw portion fit closely to the workpiece 100 through the pressure of the first conical inclined surface against the second conical inclined surface, so that the end of the workpiece 100 can be fixed to the inner periphery of the elastic sleeve 31.

[0023] In this example, the elastic sleeve 31 is made of metal material, and reference may be made to some common clamping sleeves in the prior art, such as the sleeve for clamping tools on the milling cutter handle. The connecting portion of the elastic sleeve 31 is a whole circular ring body, which is fixedly connected to the first positioning seat 10, and the clamping jaw portion is in the shape of a petal, that is, each clamping jaw is distributed along the circumference and is fixed to the connecting portion, and there is a gap between each clamping jaw. Before clamping the workpiece 100, each clamping jaw is separated from each other, so its internal space is also larger. When clamping the workpiece 100, each clamping jaw is close to each other, thereby clamping the workpiece 100.

[0024] The driver for driving the tightening sleeve 32 to move back and forth is a cylinder (not shown in the figure). When the workpiece 100 is processed, the workpiece 100 is driven by the main shaft and rotates around its own axis, so the fixture clamping it also needs to rotate. Therefore, the cylinder is fixed on the rotating shaft of the oiler like the first positioning seat 10, and the power output shaft of the cylinder is annular, and the first positioning seat 10 is located on its inner circumference.

[0025] The specific structure of the first fastening mechanism is described above. Since the first fastening mechanism and the second fastening mechanism are symmetrically arranged, that is, the specific structural arrangement of the second fastening mechanism is the same as the specific structural arrangement of the first fastening mechanism, it will not be repeated.

[0026] The oiler is arranged on the frame of the deep hole drilling and boring machine to slide along the axial direction of the workpiece 100, and is moved by a servo motor driver, so that the second positioning seat 20 and the second fastening mechanism installed on the oiler move with the movement of the oiler. When clamping the workpiece 100, the oiler drives the second positioning seat 20 and the second fastening mechanism to move toward the side of the main shaft, so that the workpiece 100 is pressed between the first positioning seat 10 and the second positioning seat 20, and finally the two ends are clamped by the first fastening mechanism and the second fastening mechanism; when the processing is completed, the first fastening mechanism is released, the oiler moves to the side away from the main shaft, and then the workpiece 100 falls off from the first fastening mechanism, and then the second fastening mechanism is released to remove the workpiece 100.

[0027] In summary, the clamping fixture for deep hole processing of thin-walled workpieces of the present invention clamps the workpiece in a double-locking manner at both ends, resulting in small deformation of the workpiece and high positioning accuracy. The clamping does not generate axial force on the workpiece, thus avoiding bending and deformation of the workpiece, which is beneficial to the stability of the workpiece processing accuracy.

[0028] When the second positioning seat moves to push the workpiece between the first positioning seat and the second positioning seat, the buffering effect of the elastic buffer pad compensates for the influence of the workpiece length error, ensures the stability and reliability of the axial positioning, and avoids the excessive collision between the two ends of the workpiece and the first positioning seat and the second positioning seat. At the same time, the elastic buffer pad can reduce the axial force generated by the thermal deformation and elongation of the workpiece, which is beneficial to ensure the processing accuracy.

[0029] The above detailed description of the present invention is intended to enable persons familiar with the art to understand the contents of the present invention and implement them. It does not limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A clamping fixture for deep hole processing of thin-walled workpieces, characterized in that: The clamping fixture comprises a first positioning seat fixedly connected to the main shaft of the machine tool, a second positioning seat docked with the rotating shaft of the oiler, a first fastening mechanism located on the side where the first positioning seat is located and used to fix one end of the workpiece relative to the first positioning seat, and a second fastening mechanism located on the side where the second positioning seat is located and used to fix the other end of the workpiece relative to the second positioning seat; and when the workpiece is clamped on the clamping fixture, the workpiece abuts between the first positioning seat and the second positioning seat; The second fastening mechanism is symmetrically arranged with respect to the first fastening mechanism; The first fastening mechanism comprises an elastic sleeve fixedly connected to the first positioning seat and a tightening mechanism for tightening the elastic sleeve; when the tightening mechanism of the first fastening mechanism tightens the elastic sleeve of the first fastening mechanism, one end of the workpiece can be fixed on the inner periphery of the elastic sleeve of the first fastening mechanism; The second fastening mechanism comprises an elastic sleeve fixedly connected to the second positioning seat and a tightening mechanism for tightening the elastic sleeve, and when the tightening mechanism of the second fastening mechanism tightens the elastic sleeve of the second fastening mechanism, the other end of the workpiece can be fixed to the inner circumference of the elastic sleeve of the second fastening mechanism; The elastic sleeves of the first fastening mechanism and the second fastening mechanism respectively have a connecting portion fixedly connected to the first positioning seat or the second positioning seat and a clamping claw portion integrally provided with the connecting portion for clamping the workpiece; The tightening mechanism of the first tightening mechanism and the second tightening mechanism comprises a tightening sleeve movably arranged along the axial direction of the workpiece, the inner circumference of the tightening sleeve is formed with a first conical inclined surface, and the outer circumference of the clamping jaw part is formed with a second conical inclined surface arranged to cooperate with the first conical inclined surface. When the tightening sleeve moves, the tightening sleeve can make the inner circumference of the clamping jaw part fit closely to the workpiece and clamp the workpiece by pressing the first conical inclined surface against the second conical inclined surface. The tightening mechanisms of the first and second tightening mechanisms further include a driver for driving the tightening sleeve to move along the axial direction of the workpiece.

2. The clamping fixture for deep hole processing of thin-walled workpieces according to claim 1 is characterized in that: The clamping fixture further comprises a buffer mechanism for providing a buffer force to the workpiece axially when the workpiece is clamped on the clamping fixture.

3. The clamping fixture for deep hole processing of thin-walled workpieces according to claim 2 is characterized in that: The buffer mechanism includes an elastic buffer pad arranged on an end surface of the second positioning seat close to the first positioning seat.

4. The clamping fixture for deep hole processing of thin-walled workpieces according to claim 3 is characterized in that: The elastic buffer pad is made of polyurethane.

5. The clamping fixture for deep hole processing of thin-walled workpieces according to claim 1, characterized in that: The inner edge of the opening of the clamping claw part is chamfered.

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