Post-heating cut-off method for combined forging piece of thin-wall bearing ring

Abstract

The invention relates to the field of manufacturing of special metal articles, in particular to a post-heating cutting method for a combined forging piece of a thin-wall bearing ring. The method is used for solving the problem that the precision of the thin-wall bearing ring is affected due to the fact that large cutting stress is easily generated when a combined forging piece is cut off in an existing method. The method comprises the following steps: (1) fixing a combined forging on a lathe; (2) a turning tool conducts turning from the two radial sides of the combined forging piece, a certain axial distance exists between the cutting feed position of turning and the parting line, cutting feed turning is conducted gradually close to the parting line through the path containing the oblique line section or the arc line section, and when turning is conducted to the parting line, cutting discharge turning is conducted gradually away from the parting line through the path containing the oblique line section or the arc line section, the turning thicknesses of the two sides are not smaller than the residual thickness at the parting line; and (3) a cut-off tool is used for conducting radial cutting at the parting line, a certain axial force can be generated when the turning tool is fed and discharged, the radial cutting stress is reduced to a certain degree, and the possibility of cutting-off deformation of the combined forge piece is reduced.

Description

Technical Field

[0001] The invention relates to the field of manufacturing special metal articles, in particular to a method for hot-post cutting of a forged piece of a thin-walled bearing ring. Background Art

[0002] Thin-walled bearings have the characteristics of small aspect ratio and 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 with limited installation space, high integration and lightweight requirements in robots, aviation, aerospace, etc. In order to improve the production cycle of thin-walled bearings and improve production efficiency, a process of forging multiple blanks is usually adopted in the forging process to obtain forgings, and then the forgings are turned, heat treated and cut. For example, a two-in-one processing method for a narrow series of thin-walled bearing rings published in the Chinese invention patent with authorization announcement number CN101109415B first clamps the forgings, then machine and heat treat the forgings, and cut the forgings after heat treatment to obtain the corresponding number of bearing rings. When cutting the forgings, a cutting tool is usually used to radially cut the forgings at the dividing line of the bearing rings of the forgings. Because the cutting tool cuts deep, it is difficult to remove chips from the tool, and the hardness of the forgings is high after heat treatment, and the conventional cutting tool is easily damaged during cutting. At the same time, a large radial cutting stress will be generated on the forging during cutting, which can easily cause deformation of the forging and affect the dimensional accuracy of the thin-walled bearing ring. Summary of the invention

[0003] The purpose of the present invention is to provide a method for hot post-cutting of forged thin-walled bearing rings to solve the problem that the existing cutting method is prone to generate large radial cutting stress when cutting forged parts, causing deformation of the bearing rings and affecting the accuracy of the bearing rings.

[0004] A method for hot cutting of a thin-walled bearing ring forging of the present invention comprises the following steps: 1) fixing the forging on a lathe workbench; 2) using a turning tool to perform turning from both radial sides of the forging, wherein the starting position of the turning feed is at a certain axial distance from the dividing line between two adjacent rings, and the turning feed is gradually approached to the dividing line using a turning path including an oblique line segment or an arc line segment, and when turning to the dividing line, the turning feed is gradually moved away from the dividing line using a turning path including an oblique line segment or an arc line segment, and the turning thickness on both radial sides is not less than the remaining thickness of the forging at the dividing line after the turning on both radial sides is completed; 3) using a cutting tool to perform radial cutting at the dividing line of the forging.

[0005] Furthermore, the infeed turning path and the outfeed turning path of the turning tool are symmetrical with respect to the dividing line.

[0006] Furthermore, after turning is completed, an isosceles trapezoidal annular groove structure is machined on the forged piece.

[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 rings.

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

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

[0010] Furthermore, the cutting tool is a diamond-shaped ceramic tool.

[0011] Furthermore, the diamond-shaped ceramic knife is a 35-degree diamond-shaped knife.

[0012] Furthermore, before step 2), the end face and outer diameter of the forged part are turned to eliminate the end face curvature and the outer diameter ovality respectively.

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

[0014] The present invention proposes a brand-new technical solution, using a turning tool to turn from both radial sides of the forged part, the starting position of the turning feed has a certain axial distance from the dividing line of the two adjacent rings, and the turning path containing an oblique line segment or an arc segment gradually approaches the dividing line for turning, and when turning to the dividing line, the turning path containing an oblique line segment or an arc segment gradually moves away from the dividing line for turning, and the turning thickness on both radial sides is not less than the remaining thickness of the forged part at the dividing line after the turning on both radial sides is completed; finally, a cutting tool is used to perform radial cutting at the dividing line of the forged part. Because the turning tool's feed turning path and the tool exit turning path respectively contain oblique line segments and arc segments that gradually approach and gradually move away from the dividing line, a certain axial force component will be generated during turning, reducing the radial cutting stress; and finally, only the remaining thickness at the dividing line of the forged part after the deformed 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 forged part, and ensures the dimensional accuracy of the thin-walled bearing ring. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 A cutting path diagram for cutting the outer ring of a tapered roller bearing using a method for hot-post cutting of a thin-walled bearing ring forging of the present invention; Figure 2 The present invention is a cutting path diagram for cutting the second bearing outer ring using a method for hot-post cutting of a thin-walled bearing ring forging of the present invention.

[0016] In the figure: 1, combined forging; 2, raceway; 3, outer diameter; 4, dividing line; 5, turning path of the turning tool on the radial outside of the combined forging; 6, turning path of the turning tool on the radial inside of the combined forging; 7, cutting direction of the cutting tool. DETAILED DESCRIPTION

[0017] The present invention proposes a new technical solution to the problems existing in the above-mentioned technical solutions, in which a turning tool is used to perform turning 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 of the two adjacent rings, and the turning feed is gradually approached to the dividing line with a turning path containing an oblique line segment or an arc line segment. When turning to the dividing line, the turning is gradually moved away from the dividing line with a turning path containing 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 is completed; finally, a cutting tool is used to perform radial cutting at the dividing line of the combined forging. Because the infeed turning path and the outfeed turning 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 force component will be generated during turning, reducing the radial cutting stress; and finally, only the remaining thickness at the dividing line of the forging after contour 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 forging, and ensures the dimensional accuracy of the thin-walled bearing ring.

[0018] In view of the above concept, a method for hot-cutting a forged thin-walled bearing ring of the present invention comprises the following steps: 1) Fix the heat-treated forging 1 on the lathe workbench (clamped with a pneumatic chuck and six-petal soft jaws). 2) The turning tool turns the forging 1 from both radial sides, and the starting position of the turning feed is at a certain axial distance from the dividing line 4 of the two adjacent rings. The turning path containing an oblique line segment or an arc segment gradually approaches the dividing line 4 for turning. When turning to the dividing line 4, the turning path containing an oblique line segment or an arc segment gradually moves away from the dividing line 4 for turning. The turning thickness on both radial sides is not less than the remaining thickness of the forging 1 at the dividing line 4 after the turning on both radial sides is completed; 3) Use a cutting tool to perform radial cutting at the dividing line 4 of the forging 1. After cutting, the cutting surface of the forging 1 is flattened to obtain a finished bearing ring. Since the infeed turning trajectory and the outfeed turning trajectory of the turning tool respectively include oblique line segments and arc segments gradually approaching and gradually moving away from the dividing line 4, a certain axial force component will be generated during turning, reducing the radial cutting stress; and finally, only the remaining thickness at the dividing line 4 of the forged part 1 after the contour turning is radially cut, and the cutting direction 7 of the cutting tool is as follows: Figure 1 , 2As shown, compared with the overall radial cutting method, this method reduces the radial cutting stress to a certain extent, reduces the possibility of cutting deformation of the forged part 1, and ensures the dimensional accuracy of the thin-walled bearing ring; at the same time, after using this cutting method, a pair of tools can be used to process 5-10 products separately, and the tool durability is greatly improved compared with the original process in which each cutting tool can only process 1-2 products.

[0019] In this embodiment, the inlet turning path and the outlet turning path of the turning tool are symmetrical with respect to the dividing line 4. In this way, the degree of turning on both sides of the dividing line 4 can be ensured to be consistent, and the structural stability of the forged part 1 after cutting can be ensured. In addition, in other embodiments, the inlet turning path and the outlet turning path of the turning tool can also be set asymmetrically with respect to the dividing line, as long as the turning trajectory of the turning tool can generate a certain axial force component on the forged part during turning to reduce the radial cutting stress.

[0020] In this embodiment, after turning, an isosceles trapezoidal annular groove structure is turned on the combined forging. The turning path of the turning tool is consistent with the contour line of the annular groove structure. This method is convenient for setting the running trajectory of the turning tool. During turning, 4 to 5 feeds are required, each back cutting amount is 1.5mm, the turning tool cutting speed is 58m / min, and the feed rate is 0.4mm / r. Finally, an isosceles trapezoidal annular groove structure is turned. In addition, in other embodiments, after turning, an isosceles triangle annular groove structure can also be turned on the combined forging; of course, in another embodiment, an annular groove structure with a bowl-shaped cross section can also be turned on the combined forging; it is easy to think that an annular groove structure with an arc-shaped cross section (including a semicircular) can also be turned. Of course, the turning path of the turning tool is consistent with the contour line of the annular groove structure.

[0021] like Figure 1 , Figure 2 In the illustrated embodiment, the turning path 5 of the turning tool on the radially outer side of the combined forging is consistent with the turning path 6 of the turning tool on the radially inner side of the combined forging. Figure 1 In order to process the forged parts of the outer ring of the tapered roller bearing, a straight section is reserved between the raceways 2 of the adjacent rings. When turning the radial inner side of the outer ring of the bearing, the turning tool enters at the end of the straight section and exits from the other end of the straight section, so the turning paths of the turning tool on both sides of the radial direction can be consistent. Of course, in other embodiments, the turning paths of the turning tool on both sides of the radial direction may also be inconsistent.

[0022] In this embodiment, if Figure 1 , Figure 2As shown, the thickness L of the combined forging at the dividing line 4 between two adjacent rings is L1+L2+L3, where L1 is the turning thickness of the combined forging on the radial outer side, L2 is the turning thickness of the combined forging on the radial inner side, and L3 is the remaining thickness of the combined forging after turning. 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 thickness 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 contour turning can also be set to other values ​​as needed, and it is only necessary to ensure that 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 is completed.

[0023] In a preferred embodiment, when turning the outer ring forging, turning is first performed from the radial outer side of the forging 1, and then turning is performed on the radial inner side of the forging 1. In another embodiment, turning may also be performed from the radial inner side of the forging first, and then turning is performed on the radial outer side of the forging.

[0024] In this embodiment, the turning tool is a square ceramic knife. Ceramic knives 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 knife enables it to better adapt to the turning of complex contours and can efficiently complete the turning. In addition, in other embodiments, the turning tool can also be a diamond-shaped ceramic knife, as long as it can meet the requirements of turning. Of course, in another embodiment, the turning tool can also be an ordinary carbide tool.

[0025] In this embodiment, the cutting tool is a diamond-shaped ceramic knife. The diamond-shaped ceramic knife 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 knife, as long as it can achieve radial cutting of the forged parts.

[0026] In a preferred embodiment, the diamond-shaped ceramic knife is a 35-degree diamond-shaped knife.

[0027] In this embodiment, the end face and the outer diameter 3 of the forged part 1 are turned before step 2) to eliminate the curvature of the end face and the ovality of the outer diameter 3 respectively. At this time, the height parallelism difference of the end face and the ovality of the outer diameter 3 need to be controlled within 0.2 mm. In this way, the position of the cutting reference, i.e., the cutting line 4 of the forged part 1, can be determined more accurately, which is convenient for the subsequent cutting of the forged part 1.

[0028] In this embodiment, the cutting tool in step 3) cuts the forged part 1 from the radial inner side to the radial outer side of the forged part 1, and the turned part of the outer diameter 3 is wrapped with tape before cutting. In this way, the corresponding bearing ring can be prevented from sliding off due to lack of support after cutting the forged part 1. In addition, in other embodiments, the cutting tool can also cut the forged part 1 from the radial outer side to the radial inner side of the forged part 1.

[0029] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. The patent protection scope of the present invention shall be based on the claims. All equivalent structural changes made using the contents of the description and drawings of the present invention should also be included in the protection scope of the present invention.

Claims

1. A method for hot-cutting a forged thin-walled bearing ring, characterized in that: The following steps are involved: 1) Fix the forging on the lathe workbench; 2) The turning tool turns the forging from both radial sides respectively, the starting position of the turning feed has a certain axial distance from the dividing line of the two adjacent rings, and the turning path containing an oblique line segment or an arc segment gradually approaches the dividing line for turning, and when turning to the dividing line, the turning path containing an oblique line segment or an arc segment gradually moves away from the dividing line for turning, and the turning thickness on both radial sides is not less than the remaining thickness of the forging at the dividing line after the turning on both radial sides is completed; 3) Use a cutting tool to perform radial cutting at the dividing line of the forging.

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

3. The method for hot cutting of forged thin-walled bearing rings according to claim 2, characterized in that: After turning is completed, an isosceles trapezoidal ring groove structure is machined on the forged part.

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

5. The method for hot cutting of a thin-walled bearing ring forging according to any one of claims 1 to 3, characterized in that: When turning the outer ring forging, first turn from the radial outer side of the forging, and then turn the radial inner side of the forging.

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

7. The method for hot cutting of a thin-walled bearing ring forging according to any one of claims 1 to 3, characterized in that: The cutting tool is a diamond-shaped ceramic tool.

8. The method for hot cutting of a forged thin-walled bearing ring according to claim 7, characterized in that: The diamond-shaped ceramic knife is a 35-degree diamond-shaped knife.

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

10. The method for hot cutting of a forged thin-walled bearing ring according to any one of claims 1 to 3, characterized in that: The cutting tool in step 3) cuts the forged part from the radial inner side to the radial outer side of the forged part, and the turned part of the outer diameter is wrapped with an adhesive tape before cutting.

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