A method for post-heat cutting of a combined forging of a thin-walled bearing ring

Abstract

The present invention relates to the field of manufacturing special metal articles, and particularly to a post-heat cutting method for a combined forging of a thin-walled bearing ring. This method is used to solve the problem that the existing methods are prone to generate large cutting stresses when cutting the combined forging, which affects the accuracy of the thin-walled bearing ring. The method includes the following steps: 1) Fix the combined forging on a lathe; 2) The turning tool turns from the radial two sides of the combined forging respectively. The feed position of the turning is at a certain axial distance from the dividing line, and feeds gradually closer to the dividing line along a path including an oblique line segment or an arc segment. When turning to the dividing line, it feeds gradually away from the dividing line along a path including an oblique line segment or an arc segment. The turning thickness on both sides is not less than the remaining thickness at the dividing line; 3) Use a cutting tool to perform radial cutting at the dividing line. Certain axial forces are generated when the turning tool feeds and retracts, reducing the radial cutting stress to a certain extent and reducing the possibility of deformation of the combined forging during cutting.

Description

Technical Field

[0001] The present invention relates to the field of manufacturing special metal articles, and particularly to a post-heat cutting method for a combined forging of a thin-walled bearing ring. Background Art

[0002] Thin-walled bearings have the characteristics of a small length-to-diameter ratio and a thin wall thickness, which helps to reduce the volume, mass, and total cost of instruments and equipment. They are widely used in host component units such as robots, aviation, and aerospace where installation space is limited, and there are high requirements for integration and lightweight. In order to shorten the production cycle of thin-walled bearings and improve production efficiency, a process of combined forging of multiple blanks is usually adopted during forging to obtain a combined forging, and then the combined forging is subjected to turning, heat treatment, and cutting. For example, a method for machining a narrow series of thin-walled bearing rings in two-in-one disclosed in the Chinese invention patent with the authorization announcement number CN101109415B first clamps the combined forging, and then performs machining and heat treatment on the combined forging. After heat treatment, the combined forging is cut to obtain the corresponding number of bearing rings. When cutting the combined forging, a cutting tool is usually used to radially cut the combined forging at the dividing line of the bearing rings of the combined forging. Since the cutting tool cuts in deeply, it is difficult for the tool to discharge chips, and the combined forging has a high hardness after heat treatment, so the conventional cutting tool is easily damaged during cutting. At the same time, a large radial cutting stress will also be generated on the combined forging during cutting, thus easily causing deformation of the combined forging and affecting the dimensional accuracy of the thin-walled bearing ring. Summary of the Invention

[0003] The purpose of the present invention is to provide a post-heat cutting method for a combined forging of a thin-walled bearing ring to solve the problem that the existing cutting method is prone to generate a large radial cutting stress when cutting the combined forging, resulting in deformation of the bearing ring and affecting the accuracy of the bearing ring.

[0004] A post-heat cutting method for a combined forging of a thin-walled bearing ring of the present invention includes the following steps: 1) Fix the combined forging on the lathe workbench; 2) The turning tools perform turning from the radial two sides of the combined forging respectively. The starting position of the feed for turning is at a certain axial distance from the dividing line between adjacent two rings, and the turning path including an oblique line segment or an arc line segment is used to gradually approach the dividing line for feed turning. When turning to the dividing line, the turning path including an oblique line segment or an arc line segment is used to gradually move away from the dividing line for cutting. The turning thickness on both radial sides is not less than the remaining thickness of the combined forging at the dividing line after turning on both radial sides; 3) Use a cutting tool to perform radial cutting at the dividing line of the combined forging.

[0005] Further, the feed turning path and the cutting path of the turning tool are symmetric with respect to the dividing line.

[0006] Further, after turning, an isosceles trapezoidal ring groove structure is turned on the combined forging.

[0007] Furthermore, the turning thickness on both radial sides of the combined forging is 2 / 5 of the thickness of the combined forging at the dividing line between two adjacent raceways.

[0008] Furthermore, when turning the outer ring combined forging, first turn from the radial outer side of the combined forging, and then turn the radial inner side of the combined forging.

[0009] Furthermore, the turning tool is a square ceramic tool.

[0010] Furthermore, the cutting tool is a rhombic ceramic tool.

[0011] Furthermore, the rhombic ceramic tool is a 35-degree rhombic tool.

[0012] Furthermore, before step 2), turn the end face and outer diameter of the combined forging to eliminate the end face curvature and outer diameter ovality respectively.

[0013] Furthermore, the cutting tool in step 3) cuts the combined forging from the radial inner side to the radial outer side, and before cutting, wind the turned part of the outer diameter with adhesive tape.

[0014] The present invention proposes a completely new technical solution. The turning tool is used to turn from both radial sides of the combined forging respectively. The starting position of the turning feed is at a certain axial distance from the dividing line between two adjacent raceways, and the turning path including an oblique line segment or an arc segment is used to gradually approach the dividing line for turning feed. When turning to the dividing line, the turning path including an oblique line segment or an arc segment is used to gradually move away from the dividing line for turning out. The turning thickness on both radial sides is not less than the remaining thickness of the combined forging at the dividing line after turning on both radial sides; finally, the cutting tool is used to perform radial cutting at the dividing line of the combined forging. Since the turning feed path and the turning out path of the turning tool respectively include oblique line segments and arc segments that gradually approach and gradually move away from the dividing line, a certain axial component force will be generated during turning, reducing the radial cutting stress; and finally, only the remaining thickness at the dividing line of the combined forging after profiling turning is radially cut. Compared with the overall radial cutting method, this method greatly reduces the radial cutting stress, reduces the possibility of cutting deformation of the combined forging, and ensures the dimensional accuracy of the thin-walled bearing raceway. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 FIG. is a cutting path diagram for cutting a tapered roller bearing outer ring using the post-heat cutting method for a combined forging of a thin-walled bearing raceway of the present invention;

[0016] Figure 2 FIG. is a cutting path diagram for cutting a second bearing outer ring using the post-heat cutting method for a combined forging of a thin-walled bearing raceway of the present invention.

[0017] In the figure: 1. Combined forging; 2. Raceway; 3. Outer diameter; 4. Dividing line; 5. Turning path of the turning tool on the radial outer side of the combined forging; 6. Turning path of the turning tool on the radial inner side of the combined forging; 7. Cutting direction of the cutting tool. Specific implementation mode

[0018] The present invention proposes a brand-new technical solution for the problems existing in the above technical solutions. The turning tool is used to perform turning from the radial two sides of the combined forging respectively. The starting position of the turning feed is at a certain axial distance from the dividing line between two adjacent rings, and the turning path containing an oblique line segment or an arc line segment is used to gradually approach the dividing line for turning. When turning to the dividing line, the turning path containing an oblique line segment or an arc line segment is used to gradually move away from the dividing line for turning out. The turning thickness on both radial sides is not less than the remaining thickness of the combined forging at the dividing line after turning on both radial sides; finally, the cutting tool is used to perform radial cutting at the dividing line of the combined forging. Since the turning feed path and the turning out path of the turning tool respectively contain oblique line segments and arc line segments that gradually approach and gradually move away from the dividing line, a certain axial component force will be generated during turning, reducing the radial cutting stress; and finally, only the remaining thickness at the dividing line of the combined forging after profiling turning is radially cut. Compared with the overall radial cutting method, this method greatly reduces the radial cutting stress, reduces the possibility of cutting deformation of the combined forging, and ensures the dimensional accuracy of the thin-walled bearing ring.

[0019] In view of the above concept, a post-heat cutting method for a combined forging of a thin-walled bearing ring of the present invention includes the following steps:

[0020] 1) Fix the heat-treated combined forging 1 on the lathe workbench (clamping with pneumatic chuck six-lobe soft jaws). 2) The turning tool performs turning from the radial two sides of the combined forging 1 respectively. The starting position of the turning feed is at a certain axial distance from the dividing line 4 between two adjacent rings, and the turning path containing an oblique line segment or an arc line segment is used to gradually approach the dividing line 4 for turning. When turning to the dividing line 4, the turning path containing an oblique line segment or an arc line segment is used to gradually move away from the dividing line 4 for turning out. The turning thickness on both radial sides is not less than the remaining thickness of the combined forging 1 at the dividing line 4 after turning on both radial sides; 3) Use the cutting tool to perform radial cutting at the dividing line 4 of the combined forging 1. After cutting is completed, the cutting surface of the combined forging 1 is turned flat to obtain the finished bearing ring. Since the turning feed trajectory and the turning out trajectory of the turning tool respectively contain oblique line segments and arc line segments that gradually approach and gradually move away from the dividing line 4, a certain axial component force will be generated during turning, reducing the radial cutting stress; and finally, only the remaining thickness at the dividing line 4 of the combined forging 1 after profiling turning is radially cut. The cutting direction 7 of the cutting tool is as Figure 1 、 2As shown, compared with the way of overall radial cutting, this method reduces the radial cutting stress to a certain extent, reduces the possibility of cutting deformation of the combined forging 1, and ensures the dimensional accuracy of the thin-walled bearing ring. At the same time, after using this cutting method, a set of tools can separately process 5-10 products. Compared with the original process where each cutting tool could often only process 1-2 products, the tool durability is greatly improved.

[0021] In this embodiment, the feed turning path and the outfeed turning path of the turning tool are symmetrical with respect to the dividing line 4. In this way, the turning degree on both sides of the dividing line 4 can be ensured to be the same, and the structural stability of the combined forging 1 after cutting is ensured. In addition, in other embodiments, the feed turning path and the outfeed turning path of the turning tool may also be asymmetrically arranged with respect to the dividing line, as long as it is ensured that the turning trajectory of the turning tool can generate a certain axial component force on the combined forging during turning to reduce the radial cutting stress.

[0022] In this embodiment, after turning, an isosceles trapezoidal ring groove structure is turned on the combined forging. The turning path of the turning tool is consistent with the contour line of the ring groove structure. This method facilitates the setting of the running trajectory of the turning tool. During turning, 4-5 feeds are required, with a back engagement of 1.5 mm each time, a cutting speed of the turning tool of 58 m / min, and a feed rate of 0.4 mm / r, and finally an isosceles trapezoidal ring groove structure is turned. In addition, in other embodiments, after turning, an isosceles triangular ring groove structure may also be turned on the combined forging; of course, in another embodiment, a ring groove structure with a bowl-shaped cross-section may also be turned on the combined forging; it is easy to think that a ring groove structure with an arc-shaped (including semi-circular) cross-section may also be turned, and of course, the turning path of the turning tool is consistent with the contour line of the ring groove structure.

[0023] As Figure 1 、 Figure 2 In the embodiment shown, the turning path 5 of the turning tool on the radial outer side of the combined forging is the same as the turning path 6 of the turning tool on the radial inner side of the combined forging. Figure 1 For machining the combined forging of the outer ring of a tapered roller bearing, a straight cylinder section is reserved between the raceways 2 of adjacent rings. When turning the radial inner side of the bearing outer ring, the turning tool feeds at the end of this straight cylinder section and exits at the other end of this straight cylinder section. Therefore, the turning paths of the turning tool on the radial two sides can be the same. Of course, in other embodiments, the turning paths of the turning tool on the radial two sides may also be different.

[0024] In this embodiment, as Figure 1 、 Figure 2As shown, the thickness L of the combined forging at the dividing line 4 between two adjacent rings is L = L1 + L2 + L3. Here, L1 is the turning thickness on the radial outer side of the combined forging, L2 is the turning thickness on the radial inner side of the combined forging, and L3 is the remaining thickness after turning the combined forging. The turning thicknesses L1 and L2 on both radial sides of the combined forging 1 are both 2 / 5 of the thickness L of the combined forging 1 at the dividing line 4 between two adjacent rings. In this way, the cutting tool only needs to radially cut 1 / 5 of the remaining thickness L3 of the combined forging 1, reducing the radial cutting stress and ensuring the cutting effect. In addition, in other embodiments, the turning thicknesses on both radial sides of the combined forging can also be 1 / 3 of the thickness of the combined forging. Of course, in other embodiments, the turning thickness of each profile turning can also be set to other values as needed, as long as it is ensured that the turning thicknesses on both radial sides are not less than the remaining thickness of the combined forging at the dividing line after turning on both radial sides.

[0025] In a preferred embodiment, when turning the outer ring combined forging, first turn from the radial outer side of the combined forging 1, and then turn the radial inner side of the combined forging 1. In another embodiment, it is also possible to first turn from the radial inner side of the combined forging and then turn the radial outer side of the combined forging.

[0026] In this embodiment, the turning tool is a square ceramic tool. Ceramic tools have the advantages of high hardness and high wear resistance, and can still maintain good hardness and cutting performance at high temperatures. The design of the square ceramic tool enables it to better adapt to turning complex profiles and can complete turning efficiently. In addition, in other embodiments, the turning tool can also be a rhombic ceramic tool, as long as it can meet the requirements of turning. Of course, in another embodiment, the turning tool can also be an ordinary cemented carbide tool.

[0027] In this embodiment, the cutting tool is a rhombic ceramic tool. The rhombic ceramic tool helps to disperse the cutting force during the processing, helps to reduce the wear of the tool, and can also improve the processing accuracy. In addition, in other embodiments, the cutting tool can also be a triangular ceramic tool, as long as it can achieve radial cutting of the combined forging.

[0028] In a preferred embodiment, the rhombic ceramic tool is a 35-degree rhombic tool.

[0029] In this embodiment, before step 2), turn the end face and outer diameter 3 of the combined forging 1 to eliminate the end face curvature and the ovality of the outer diameter 3 respectively. At this time, the height parallelism of the end face and the ovality of the outer diameter 3 need to be controlled within 0.2 mm. In this way, the cutting reference, that is, the position of the dividing line 4 of the combined forging 1, can be determined more accurately, facilitating subsequent cutting of the combined forging 1.

[0030] In this embodiment, the cutting tool in step 3) cuts the combined forging 1 from the radially inner side to the radially outer side of the combined forging 1, and the turning part of the outer diameter 3 is wound with tape before cutting. In this way, it is possible to prevent the corresponding bearing ring from slipping due to lack of support after cutting the combined forging 1. In addition, in other embodiments, the cutting tool may also cut the combined forging 1 from the radially outer side to the radially inner side of the combined forging 1.

[0031] The above is only a preferred embodiment of the present invention and is not intended to limit the present invention. The scope of patent protection of the present invention is subject to the claims. All equivalent structural changes made by using the content of the specification and drawings of the present invention should, by the same token, be included in the protection scope of the present invention.

Claims

1. A method for post-heat cutting of a combined forging of a thin-wall bearing ring, characterized in that: It includes the following steps: 1) Fix the combined forging on the lathe workbench; 2) The turning tools perform turning from the radial two sides of the combined forging respectively. The starting position of the cutting feed is at a certain axial distance from the dividing line between two adjacent rings, and the cutting feed is gradually close to the dividing line with a turning path including an oblique line segment or an arc line segment. When turning to the dividing line, the cutting feed is gradually away from the dividing line with a turning path including an oblique line segment or an arc line segment. The turning thickness on both radial sides is not less than the remaining thickness of the combined forging at the dividing line after turning on both radial sides; 3) Use a cutting-off tool to perform radial cutting at the dividing line of the combined forging.

2. The hot cutting method for the forging of the thin-walled bearing ring according to claim 1, characterized in that: The cutting feed turning path and the cutting-out turning path of the turning tool are symmetrical with respect to the dividing line.

3. The post-heat cutting method for the forged combination of thin-walled bearing rings according to claim 2, characterized in that: After turning, a ring groove structure in the shape of an isosceles trapezoid is turned on the combined forging.

4. The post-heat cutting method for the forged blank of the thin-walled bearing ring according to any one of claims 1-3, characterized in that: The turning thickness on both radial sides of the combined forging is 2 / 5 of the thickness of the combined forging at the dividing line between two adjacent rings.

5. The post-heat cutting method for the forged assembly of the thin-wall bearing ring according to any one of claims 1-3, characterized in that: When turning the outer ring combined forging, first turn from the radial outside of the combined forging, and then turn the radial inside of the combined forging.

6. The hot cutting method for the forged blank of the thin-wall bearing ring according to any one of claims 1-3, characterized in that: The turning tool is a square ceramic tool.

7. The hot cutting method for the forged assembly of thin-walled bearing rings according to any one of claims 1-3, characterized in that: The cutting-off tool is a rhombic ceramic tool.

8. The post-heat cutting method for the forged blank of the thin-walled bearing ring according to claim 7, characterized in that: The rhombic ceramic tool is a 35-degree rhombic tool.

9. The hot cutting method for the forged blank of the thin-walled bearing ring according to any one of claims 1-3, characterized in that: Before step 2), turn the end face and outer diameter of the combined forging to eliminate the end face curvature and outer diameter ovality respectively.

10. The hot cutting method for the forged blank of the thin-walled bearing ring according to any one of claims 1-3, characterized in that: The cutting-off tool in step 3) cuts the combined forging from the radial inside to the radial outside direction of the combined forging, and before cutting, wind the turned part of the outer diameter with tape.

Images