RU2745597C1 - Method of clamping a thin-walled cylindrical part - Google Patents

Abstract

FIELD: mechanical engineering.

SUBSTANCE: invention relates to mechanical and heat treatment of a metal thin-walled cylindrical part. One should carry out either cryogenic treatment or stress relieving treatment of a pipe and a band. The inside diameter of the band is machined to the outer diameter of the pipe. To produce a workpiece, one should screw two bands onto pipe ends. The workpiece is fixed along the external surface generator of the band into a chuck. The workpiece is fixed with a clamp. After that one should check coaxiality tolerance of the workpiece relative to the axis of the machine chuck. It's necessary to ensure that the axis of the chuck is aligned with the axis of the workpiece. The outer forming surface of the band, which is not clamped in the chuck, is machined to achieve a circular shape. The workpiece is placed on the steady rest. The clamp is removed from the workpiece for further machining of the workpiece.

EFFECT: invention makes it possible to achieve the target geometric parameters of the thin-walled pipe and to machine long thin-walled pipes as a result of a uniform external load on the outer wall of the pipe, uniform compression of the pipe during tightening, the absence of pipe deformation, increased pipe rigidity and increased positioning accuracy.

6 cl, 3 dwg

Description

Technology area

This technical solution relates to the field of mechanical and thermal processing of metals. More specifically, to chucks and expanding mandrels. It can be used when processing thin-walled cylindrical parts.

Prior art

You know the device described in the author's certificate of the USSR No. 1834754 "Method of clamping thin-walled tubular parts" IPC: В23В 31/00; priority 06.09.1990, published 15.08.1993, authors: Mazanik O.N., Pavlovsky A.N. (SU).

A method of clamping thin-walled tubular parts, in which the part is clamped along the outer and inner surfaces by cams installed opposite each other, characterized in that, in order to expand technological capabilities by fixing short and long parts, the part is installed in the chuck of the machine, then a quill is inserted into its hole with tailstock cams and simultaneously clamp with all cams.

Features that coincide with the essential features of the invention - a method of clamping thin-walled tubular parts, in which the part is clamped along the inner surface; the part is installed in the chuck of the machine.

The disadvantages of this method include the inability to process the inner diameter of the workpiece, as well as the impossibility of processing workpieces and parts of large diameter. Complexity of the process, low productivity, deformation from compression forces.

As a prototype for the method was chosen USSR inventor's certificate No. 487719 "Method of clamping thin-walled cylindrical parts" IPC: В23В 31/40; priority 27.06.1973, published 15.10.1975, authors: Pashkov E.V. and Yakhimovich V.A. (SU).

A method of clamping thin-walled cylindrical parts by radially directed forces, characterized in that, in order to reduce the deformation of the part, the latter is preliminarily compressed (unclenched) along the entire contour in the clamping plane, after which the part is fixed by applying clamping forces from the opposite side.

Features that coincide with the essential features of the invention - a method of clamping thin-walled cylindrical parts by radially directed forces; the latter is preliminarily compressed along the entire contour in the clamping plane; fix the part by applying clamping forces.

The disadvantages of this method include: uneven external load on the outer walls of the part due to the variable section of the device; uneven compression of the part during tightening (an ellipse is formed); the impact from the forces of clamping the cartridge on the inner walls of the part will lead to deformation of the part; the design of the device does not allow installing long parts in the steady rest.

Disclosure of invention

The problem to be solved by the claimed invention is the development of a method for clamping a thin-walled cylindrical part, in which the specified geometric parameters of a thin-walled part are preserved, and processing of a long thin-walled part is possible.

The technical result consists in a uniform external load on the outer wall of the part, uniform compression of the part during tightening, no deformation of the part, increasing the rigidity of the part, increasing the positioning accuracy, changing the design of the band.

The technical result is achieved by the fact that in the method of clamping a thin-walled cylindrical part, containing the compression of a thin-walled part by radially directed forces with a bandage along the entire contour in the clamping plane to obtain a workpiece, fixing the workpiece with the application of a clamping force, according to the invention, heat treatment of the part is carried out, the inner diameter of the band is machined to the actual minimum outside diameter of the part. Mount the bandage on the part. The workpiece is fixed along the outer generating surface of the band in the chuck of the machine, applying forces in the direction of the radially directed forces of compression of the band. The workpiece is fixed with a clamp, the tolerance of the workpiece coaxiality relative to the axis of the machine chuck is verified. The outer forming surface of the band is machined, the workpiece is placed on the steady rest of the machine, the clamp is removed from the workpiece, for further processing of the workpiece.

The set of essential features provides a technical result, which consists in a uniform external load on the outer walls of the part, uniform compression of the part during tightening, no deformation of the part, increasing the rigidity of the workpiece, increasing the positioning accuracy and changing the design of the band.

This makes it possible to solve the problem of developing a method for clamping a thin-walled cylindrical part, in which the specified geometric parameters of the part are preserved, and it is also possible to process a long part.

The achieved result is provided not only by the presence of known distinctive features, but also depends on their interaction with other essential features of the proposed method. This allows you to expand the functionality of the method, to provide a solution to the problem.

The expanded function provided by the known and distinctive features, and obtaining a non-obvious result from the use of these features in the form of obtaining a balance of the workpiece in conjunction with other features, indicates the compliance of the proposed technical solution with the criterion of "inventive step".

Brief Description of Drawing Figures

FIG. 1 shows the appearance of the installed bandages.

FIG. 2 shows a diagram of the installation of a workpiece for turning.

FIG. 3 shows a diagram of radially directed compression forces.

Embodiments of the invention

The embodiment considered here is not the only one, but allows other options that do not contradict the claims.

As shown in FIG. 1, the workpiece 1 consists of a thin-walled part in the form of a pipe 2, which is compressed by the bandages 3 along the contour.

The method is implemented as follows. Heat treatment of pipe 2 and band 3 is carried out. It is possible to perform a strengthening heat treatment of pipe 2. In this case, the material of pipe 2 acquires the specified mechanical characteristics. The plasticity of the material becomes lower, characteristics such as strength and hardness increase.

This allows you to obtain the technical result of increasing the rigidity of the pipe 2 while maintaining its specified geometric parameters.

It is possible to perform heat treatment of the pipe material 2 without hardening, but to relieve internal stresses. For any heat treatment of pipe 2, a hardening heat treatment of the bandages 3 is carried out.

This allows you to obtain the technical result of the absence of deformation of the pipe 2 while maintaining its specified geometric parameters.

Initially, the bandage 3 is made with an inner diametrical dimension with a machining allowance. The inner diameter of the band 3 is machined to the actual minimum outer diameter of the pipe 2.

This allows you to obtain a technical result in the form of uniform compression and fit of the band 3, which allows you to maintain the specified geometric parameters of the pipe 2 during further processing.

Installation of two bandages 3 on the pipe 2 is carried out.

This allows you to obtain the technical result - increasing the rigidity of the structure of the workpiece 1 in the absence of deformation of the pipe 2. This allows you to solve the problem of maintaining the specified geometric parameters of the part.

To simplify the installation process, the bandage 3 is screwed onto the pipe 2. This allows for uniform compression while maintaining the diametrical size of the pipe 2, which improves the quality and accuracy of the pipe 2.

Thin-walled pipe 2 is compressed from two ends with two bandages 3 along the entire contour in the clamping plane to obtain a workpiece 1. The clamping plane coincides with the section plane A-A (Fig. 2, Fig. 3).

The number of installed bandages 3 is not limited, and depends on the length of the pipe 2. The longer the pipe 2, the more bands 3 can be installed on its outer surface. This makes it possible to increase the rigidity of the pipe 2 and the possibility of processing the long pipe 2 while maintaining its specified geometric parameters.

As shown in FIG. 2 and FIG. 3, the workpiece 1 with two bands 3 is fixed along the outer generating surface of the band 3 into the chuck 4 of the machine, applying the clamping forces 5 in the direction of the radially directed compression forces 6 of the band 3. The workpiece 1 is fixed with the clamp 7. In this case, as shown in FIG. 3, the clamping forces 6 act on the pipe 2 evenly, and the clamping forces 5 act only on the band 3.

This makes it possible to exclude deformation of the pipe 2 while maintaining the specified geometric parameters, since mechanical influences from the clamping force 5 of the machine tools on the walls of the pipe 2 are excluded.

Align the tolerance of the coaxiality of the workpiece 1 relative to the axis of the chuck 4 of the machine at four evenly spaced points on the workpiece 1. Ensure the coincidence of the axis of the chuck 4 with the axis 8 of the workpiece 1.

This makes it possible to increase the positioning accuracy of the workpiece on the machine, which makes it possible to process a long, thin-walled workpiece 1 while maintaining its specified geometric parameters.

The outer forming surface of the band 3, which is in a free state, not clamped in the chuck 4, is mechanically processed before being installed in the steady 9 to achieve a circular shape. The workpiece 1 is installed in the steady 9, the clamp 7 is removed from the workpiece 1 for further processing of the workpiece 1.

This allows you to eliminate beating and vibration during the rotation of the workpiece 1 in the steady 9. This allows you to solve the problem of processing a long thin-walled workpiece 1 by changing the design of the band 3 while maintaining its specified geometric parameters.

Thus, the combination of essential features in the claims allows obtaining the technical result - uniform external load on the outer walls of the pipe, uniform compression of the pipe during tightening, no pipe deformation, increase in pipe stiffness, increase in positioning accuracy, change in design, which makes it possible to solve the problem of maintaining the specified geometric parameters of a thin-walled pipe, the ability to process a long thin-walled pipe.

Industrial applicability

The proposed invention can be used for the manufacture of thin-walled, low-rigid, cylindrical bodies, pipes, closed vessels in nuclear power, oil and gas industry, mechanical engineering, space and other industries, where increased requirements are imposed on physical and mechanical, geometric parameters, etc. ...

Were tested the proposed version of the method of clamping a thin-walled cylindrical part on existing equipment using available materials. The results obtained prove its efficiency and confirm its industrial applicability.

Claims (6)

1. A method of clamping a thin-walled cylindrical part for its machining, comprising compressing a thin-walled part by radially directed forces by a bandage along the entire contour in the clamping plane to obtain a workpiece, securing the workpiece with the application of a clamping force, characterized in that heat treatment of the part is carried out, the inner diameter of the bandage is ground to the actual minimum outer diameter of the part, the band is mounted on the part, the workpiece is fixed along the outer generating surface of the band into the chuck of the machine, applying forces in the direction of the radially directed forces of compression of the band, the workpiece is fixed with a clamp, the tolerance of the coaxiality of the workpiece relative to the axis of the chuck of the machine is verified, the outer forming surface of the band machining, placing the workpiece in the steady rest of the machine, removing the clamp from the workpiece for subsequent machining of the thin-walled cylindrical part. 2. The method according to claim 1, characterized in that a hardening heat treatment of the thin-walled cylindrical part is carried out. 3. The method according to claim 1, characterized in that heat treatment of the thin-walled cylindrical part is carried out to relieve internal stress. 4. The method according to claim 1, characterized in that a hardening heat treatment of the bandage is carried out. 5. The method according to claim 1, characterized in that during installation, the bandage is screwed onto a thin-walled cylindrical part. 6. The method according to claim 1, characterized in that the tolerance of the workpiece alignment relative to the axis of the chuck of the machine is verified at four evenly spaced points on the workpiece.

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