Clamping device for turning outer circle of part with large length-diameter ratio

Abstract

The utility model relates to the technical field of aviation machining, in particular to a clamping device for turning the outer circle of a part with a large length-diameter ratio. Comprising a machine tool chuck, a center and a counter center, the center is a cone, and a coaxial threaded hole is formed in the center; the counter center is a step shaft, a taper hole is formed in the counter center, and the taper hole is in clearance fit with the cone in appearance. One end of the large-length-diameter-ratio part is fixed through a machine tool chuck, and the other end of the large-length-diameter-ratio part is in threaded connection with the center which is arranged in the counter center.

Description

Technical Field

[0001] The utility model relates to the technical field of aviation mechanical processing, in particular to a clamping device for turning the outer circle of parts with a large aspect ratio. Background Art

[0002] As a key part of hydraulic servo valve, the flexible rod connects multiple components in series and plays an important connecting role. Its small size and shape changes will cause the performance of the hydraulic servo valve to change. The length of the flexible rod ranges from 200 to 300, and the aspect ratio is about 80 or even as high as 100. It is an extremely weak rigidity part, and its processing deformation problem has always been a difficult problem in the field of mechanical processing.

[0003] When turning is performed using the traditional center clamping method, the flexible rod is easily bent and deformed along the axis due to the top clamping force, resulting in the phenomenon of "cutting off the tool", which leads to low processing accuracy, poor straightness, difficult to ensure product consistency, and low qualified rate of adjustment. In addition, the processing requirements are extremely high, and it is extremely sensitive to the top clamping force of the equipment and the skill level of the processor. Most of the processing is done on manual lathes with small top clamping force, which makes it difficult to improve the processing efficiency. Utility Model Content

[0004] The utility model aims to provide a clamping device for external turning of parts with large aspect ratio, which has high processing efficiency and stable and reliable processing quality.

[0005] The technical solution of the utility model is: the utility model provides a clamping tool for turning the outer circle of a product with a large aspect ratio on a general purpose CNC lathe. Taking a flexible rod part as an example, by clamping the tapered outer circle of the tool on the CNC lathe, external threads for matching are pre-processed at both ends of the flexible rod, and the tool internal threads are connected with the flexible rod at the same time, thereby reducing the bending deformation of the flexible rod caused by the top tightening force during the clamping process.

[0006] A clamping device for external turning of parts with large aspect ratio, comprising: a machine tool chuck, a center, and a counter center;

[0007] The top is a cone with a coaxial threaded hole inside;

[0008] The reverse tip is a stepped shaft with a tapered hole inside, and the tapered hole is in clearance with the cone shape;

[0009] One end of the part with a large aspect ratio is fixed by a machine tool chuck, and the other end is screwed into the center, and the center is set in the counter center.

[0010] Furthermore, the depth of the threaded hole at the top is not less than 20 mm, which increases the connection strength and support rigidity.

[0011] Furthermore, the clearance value between the tapered holes of the top and the counter-top is within 0.002 mm.

[0012] Furthermore, the taper of the reverse center taper hole is 12°±1°.

[0013] Furthermore, the coaxiality between the tapered holes of the top and the counter-top is within 0.02 mm.

[0014] Furthermore, the top material is brass and the counter-top material is tool steel.

[0015] Beneficial technical effects:

[0016] The utility model provides a clamping device for external turning of parts with large aspect ratio. By changing the clamping method, the contact method of part processing is changed from the previous "point contact" to "surface contact" by adopting the "top support" clamping method, which greatly suppresses the deformation of the parts. In addition, due to the greatly improved rigidity of the parts after adopting the new clamping tooling, the number of processing steps is reduced, and the processing efficiency of the parts is improved by more than 30%. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solution of the embodiments of the utility model, the following is a brief introduction to the drawings required for use in the embodiments of the utility model. It is obvious that the drawings described below are only some embodiments of the utility model. For those skilled in the art, other drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 It is a schematic diagram of a clamping tooling structure for external turning of parts with a large aspect ratio provided in an embodiment of the present application;

[0019] Figure 2 It is a schematic diagram of a clamping tooling application part for external turning of parts with a large aspect ratio provided in an embodiment of the present application;

[0020] Figure 3 It is a cross-sectional view of a clamping tool for external turning of parts with a large aspect ratio provided in an embodiment of the present application;

[0021] Figure 4 It is a schematic diagram of a machine tool tailstock reverse center for clamping tooling for external turning of parts with a large aspect ratio, provided in an embodiment of the present application.

[0022] Among them: 1-machine tool chuck; 2-flexible rod part; 3-clamping tool; 4-counter-center; 5-external thread; 6-internal thread; 7-tool friction surface; 8-counter-center friction surface. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solution and advantages of the embodiment of the utility model clearer, the technical solution in the embodiment of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiment of the utility model. Obviously, the described embodiment is a part of the embodiment of the utility model, not all of the embodiments. Based on the embodiment of the utility model, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the utility model.

[0024] The features and illustrative embodiments of various aspects of the utility model will be described in detail below. In the detailed description below, many specific details are proposed in order to provide a comprehensive understanding of the utility model. However, it is obvious to those skilled in the art that the utility model can be implemented without the need for some of these specific details. The following description of the embodiments is only to provide a better understanding of the utility model by illustrating examples of the utility model. The utility model is by no means limited to any specific settings and methods proposed below, but covers any improvements, replacements and modifications of structures, methods, devices without departing from the spirit of the utility model. In the accompanying drawings and the following description, known structures and technologies are not shown to avoid unnecessary ambiguity in the utility model.

[0025] A clamping device for external turning of parts with large aspect ratio, such as Figure 1-Figure 4 The structure mainly includes: a machine tool chuck, a center, and a counter center; wherein the center is a cone with a coaxial threaded hole inside; wherein the counter center is a stepped shaft with a tapered hole inside, and the tapered hole and the cone shape have a clearance fit; one end of the part with a large aspect ratio is fixed by the machine tool chuck, and the other end is screwed in the center, and the center is set in the counter center.

[0026] A clamping tool for external turning of parts with a large aspect ratio, the use of which includes the following steps:

[0027] Take the flexible rod as an example, the external threads are pre-processed on both ends of the part, the flexible rod is placed horizontally, the internal threads of the tooling are matched with the external threads at the ends of the flexible rod, and the tooling is connected to the machine tool through the tailstock of the machine tool;

[0028] The outer circle of the machine tool clamping fixture should be maintained at a reasonable clamping depth to avoid bending caused by inertial motion of the extended part during processing;

[0029] The clamping tool drives the parts and the tailstock counter-center to rotate together through friction, and the threaded connection provides support area and multi-directional support to reduce the bending of the parts.

[0030] The processing method using the tooling may include the following steps:

[0031] S1, place the 2 flexible rod parts horizontally and clamp one end of them to the chuck of the 1 machine tool;

[0032] S2, tighten the other end of the flexible rod-like part 2 to the thread 6 of the clamping fixture 3 through the thread 5;

[0033] S3, clamping the conical outer friction surface 7 of the tool 3 through the anti-center friction surface 8 of the tailstock of the machine tool 4;

[0034] S4, adjust the machine tool so that 1 machine tool chuck, 2 flexible rod part, 3 clamping tool, 4 machine tool tailstock counter center are kept horizontal and coaxial.

[0035] The utility model solves the problem that typical flexible rod products are prone to bending and deformation during the turning process. The tooling adopts a "top support" clamping method, and changes the contact method of the flexible rod fine turning from the previous "point contact" to "surface contact", which greatly reduces the compressive stress on the flexible rod at the local position. The increase in the contact area between the tooling and the workpiece can provide axial and radial support for the parts, and suppress the deformation of the parts. In addition, since the rigidity of the parts is greatly improved after the new clamping tooling is adopted, the number of processing steps can be reduced from 5 to 3 when processing the thin ribs of the flexible rod, which greatly improves the processing efficiency of the parts. The utility model solves the problem of bending and deformation of flexible rod parts during the processing. The parts processed by the embodiment method of the utility model have good consistency, high processing efficiency, and very high product precision. It also realizes the "manual to CNC" processing of this type of large aspect ratio parts, and the processing efficiency is significantly improved.

[0036] It should be noted that, in the absence of conflicts, those skilled in the art may flexibly adjust the order of the above-mentioned operating steps according to actual needs, or flexibly combine the above-mentioned steps.

[0037] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the utility model, but the protection scope of the utility model is not limited thereto. Any technician familiar with the field can easily think of various equivalent modifications or substitutions within the technical scope disclosed in the utility model, and these modifications or substitutions should be included in the protection scope of the utility model.

Claims

1. A clamping device for external turning of parts with large aspect ratio, characterized in that: The device comprises: a machine tool chuck, a center, and a counter center; The top is a cone with a coaxial threaded hole inside; The reverse tip is a stepped shaft with a tapered hole inside, and the tapered hole is in clearance with the cone shape; One end of the part with a large aspect ratio is fixed by a machine tool chuck, and the other end is screwed into the center, and the center is set in the counter center.

2. The device according to claim 1, characterized in that: The depth of the threaded hole at the top shall not be less than 20mm.

3. The device according to claim 1, characterized in that: The clearance between the tapered holes of the top and the counter-top is within 0.002mm.

4. The device according to claim 1, characterized in that: The taper of the reverse center cone hole is 12°±1°.

5. The device according to claim 1, characterized in that: The coaxiality between the tapered holes of the top and the counter-top is within 0.02mm.

6. The device according to claim 1, characterized in that: The tip is made of brass and the counter tip is made of tool steel.

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