Crossed roller bearing and manufacturing method thereof

Abstract

The invention relates to the technical field of bearings, and particularly discloses a crossed roller bearing and a manufacturing method thereof.The manufacturing method comprises the steps that S10, a bearing ring and a plug are preprocessed; s20, preassembling is carried out; s30, rough machining is conducted; s40, heat treatment; s50, finish machining is conducted; s60, assembling is conducted; and S70, welding is conducted. According to the crossed roller bearing and the manufacturing method thereof, through the special design of the plug and the filling hole, the traditional structural form that the plug is positioned and fixed through a conical pin is changed, the plug can be effectively prevented from moving in any direction in the filling hole, the repeated positioning precision of assembling and returning to the original position after the plug is disassembled is avoided, and the production efficiency is improved. And the yield of one-time assembly of the bearing is greatly improved. A structural mistake proofing mechanism is constructed, the problem that the plug is reversely installed in the assembling process can be effectively prevented, and the assembling efficiency and the assembling accuracy are improved; and the structural stability after assembly is remarkably improved, and the problem of bearing clamping stagnation or abnormal sound caused by displacement of the plug due to vibration or operation impact is effectively prevented.

Description

Technical Field

[0001] The present invention relates to the technical field of bearings, and particularly to an angular contact ball bearing and a manufacturing method thereof. Background Art

[0002] Angular contact ball bearings are widely used in high-precision robots, numerical control machine tools and other fields because they can simultaneously bear radial, axial and tilting moments. In a traditional angular contact ball bearing, roller loading holes are usually pre-opened on the inner ring or outer ring of the bearing, and plugs adapted to the roller loading holes are preset. A tapered hole extending radially is provided on the plug, and a pin hole corresponding to the position of the tapered hole is provided on the end face of the inner ring or outer ring of the bearing. For example, the rotary rolling bearing disclosed in the Chinese utility model patent with the publication number CN2607464Y. During assembly, rollers are filled through the roller loading holes. After the filling is completed, the plug is placed into the roller loading hole, and a tapered pin is inserted into the pin hole and the tapered hole from the end face of the bearing, so as to position and fix the plug.

[0003] The above-mentioned traditional angular contact ball bearing structure and its assembly method have the following technical defects: (1) The assembly process is cumbersome: During the assembly process, the plug and the tapered pin need to be assembled first. After the assembly is completed, turning processing is performed on the tapered pin and the plug. After the turning processing is completed, the tapered pin and the plug are removed for roller filling. After the filling is completed, the plug and the tapered pin are installed again. Since the tapered pin and the plug need to be turned simultaneously, there are many turning surfaces. During the assembly process, multiple disassembly and assembly operations are likely to cause damage to the mating surfaces and reduce the accuracy.

[0004] (2) Poor precision consistency: The plug is processed separately from the inner and outer rings. Affected by manufacturing tolerances, there are often gaps at the raceway after assembly, and the rollers will generate vibration and uneven loads during operation.

[0005] (3) Low yield rate: The assembly dimensions are limited by the cumulative errors of multiple part dimensions (such as plugs, tapered pins, pin holes, tapered holes), with poor robustness, and it is easy to generate assembly interference or looseness, making quality control difficult.

[0006] (4) Great influence of heat treatment: The inner and outer rings of the bearing or the pin holes and tapered holes may be deformed after heat treatment, making it difficult to assemble the plug or the fit clearance not reaching the preset precision, further reducing the product qualification rate.

[0007] In addition, the Chinese invention patent with publication number CN104295598A discloses a slewing bearing with a through hole and a plug. In the solution disclosed in the patent, a through hole for inserting a roller for assembly and maintenance is provided on a ring serving as the inner ring or outer ring of the bearing, and a plug for closing the through hole is provided, wherein the through hole is a stepped hole, and the plug is a stepped shaft structure adapted to the stepped hole. In the solution disclosed in the patent, although the plug has a different structure than the traditional cross roller bearing, and there is one less tapered pin structure, which reduces the number of parts and turning surfaces, and improves the cumulative assembly error, the solution still has the following technical defects: (1) The clearance between the through hole and the plug makes it easy to insert manually, but it also makes it difficult to stably position the plug before assembly is completed. Before the raceway is completely closed or fixed with pins / screws in time, the plug is very likely to loosen or fall off during transportation, flipping or slight vibration, which may potentially interfere with the subsequent assembly process and affect assembly efficiency and safety.

[0008] (2) The large diameter section and the small diameter section of the through hole are concentric. Correspondingly, the large diameter section and the small diameter section of the plug are coaxial. There is a lack of anti-rotation design in the circumferential direction. After assembly, the plug may rotate due to vibration or force during operation, which may cause misalignment or interference with the contact surface of the raceway.

[0009] (3) There is no tapered guide section at the connection between the plug and the through hole, which results in poor centering during the assembly process. Especially under small clearance fit, the lack of a guide taper makes it easy for "edge jamming" or "repeated trial assembly" to occur, resulting in poor assembly efficiency and consistency, increasing the difficulty of assembly, requiring a high level of operator proficiency, and not conducive to subsequent automated assembly.

[0010] (4) The large diameter section and small diameter section of the through hole are concentric, and the large diameter section and small diameter section of the plug are coaxial, presenting a completely symmetrical design. There is a lack of assembly error prevention mechanism, and there is a risk of wrong installation. After the raceway is processed, even if the plug is installed 180° in reverse, it cannot be identified by appearance or assembly resistance, and it is very easy to make a "reverse assembly" error. Once the plug is installed in reverse, the raceway surface will have a step misalignment, which seriously affects the smoothness of the roller operation and the overall service life. Summary of the invention

[0011] The technical problem to be solved by the present invention is to provide an improved cross roller bearing and a manufacturing method thereof, so as to solve the technical defects existing in the structure and assembly method of the cross roller bearing in the prior art.

[0012] In order to solve the above technical problems, the present invention provides the following technical solutions: A method for manufacturing a cross roller bearing, comprising the following steps: S10: pre-processing the bearing ring and the plug, wherein the bearing ring and the plug are made of the same material; Among them, the plug includes a columnar section and a lug structure located at one end of the columnar section. A first positioning step is formed between the columnar section and the lug structure, and the projection of the lug structure in the axial direction of the columnar section is asymmetrically designed based on the axis of the columnar section; Among them, the bearing ring is provided with a loading hole adapted to the plug. The loading hole includes a circular hole adapted to the columnar section and a slot hole adapted to the lug structure. A second positioning step adapted to the first positioning step is formed between the slot hole and the circular hole; Among them, a small taper fit is formed between the lug structure and the slot hole; S20: Pre-assembly. Press the plug into the loading hole. By upsetting the outer end surface of the lug structure on the plug, the lug structure and the slot hole are in a slightly interference fit; S30: Rough machining. Rough machine the inner ring surface and the outer ring surface of the assembly formed in S20 by turning; S40: Heat treatment. Heat treat and harden the assembly obtained in S30 to obtain the required hardness; S50: Finish machining. Finish machine the inner ring surface and the outer ring surface of the assembly obtained in S40 to the required precision; S60: Assembly, including at least the following steps: S61: Remove the plug from the assembly obtained by finish machining in S50; S62: Load the rollers and the spacer blocks into the raceway between the bearing inner ring and the bearing outer ring through the loading hole; S63: After the rollers and the spacer blocks are installed, install the plug into the loading hole; S70: Weld and fix the plug and the bearing ring.

[0013] In a preferred embodiment, the interference amount between the lug structure and the slot hole is 5 μm - 50 μm.

[0014] In a preferred embodiment, the taper angle between the lug structure and the slot hole is 0.5° - 7°.

[0015] In a preferred embodiment, the bearing ring provided with the loading hole is a bearing inner ring or a bearing outer ring.

[0016] In a preferred embodiment, at least one plane is provided in the circumferential direction of the lug structure.

[0017] In a preferred embodiment, in S70, laser welding process is used for welding.

[0018] The present invention also discloses an angular contact ball bearing processed by the manufacturing method.

[0019] The crossed roller bearing of the present invention and its manufacturing method have the following beneficial effects compared with the prior art: (1) The first step and the second step achieve precise positioning in the axial direction of the loading hole, which can effectively prevent the plug from moving axially in the loading hole. At the same time, it also provides stable support for the subsequent welding process of the plug.

[0020] (2) The lug structure has a structural form with an asymmetric design in the projection of the axis direction of the columnar section based on the axis of the columnar section, constructing a structural anti-misalignment mechanism, enabling the plug to be inserted into the loading hole in only one correct posture, avoiding assembly errors from the source, ensuring the repeat positioning accuracy of the plug when disassembled and then reassembled back to the original position, and greatly improving the qualification rate of the first assembly of the crossed roller bearing.

[0021] (3) The lug structure has a structural form with an asymmetric design in the projection of the axis direction of the columnar section based on the axis of the columnar section, realizing the circumferential locking fit between the plug and the loading hole, eliminating the risk of the plug rotating, significantly improving the structural stability after assembly, and effectively preventing problems such as bearing jamming or abnormal noise caused by the displacement of the plug due to vibration or operating impact.

[0022] (4) The lug structure of the plug has a slightly interference fit with the slot hole of the loading hole. While ensuring reliable fixation, it does not affect the operability during the assembly process, and is also convenient for realizing the simulation assembly and fit adjustment before subsequent heat treatment.

[0023] (5) The lug structure of the plug has a small taper fit with the slot hole of the loading hole, with functions of guiding assembly, initial positioning and self-locking. After the conical angle is less than the friction self-locking angle, the plug will not loosen by itself after the press-fitting is completed. The combination of the taper fit design and the interference fit design keeps the plug stable before welding, significantly improving the process robustness.

[0024] (6) The combination of the step positioning and interference fit between the plug and the loading hole can effectively avoid the axial movement and rotational misalignment of the plug. At the same time, the self-aligning ability of the plug during the insertion process is further enhanced through the taper fit design, which can effectively prevent the plug from moving in any direction in the loading hole, thereby improving the overall positioning accuracy.

[0025] (7) The special design of the plug and the loading hole changes the traditional structural form of positioning and fixing the plug through a tapered pin, reducing the number of traditional turning surfaces. The disassembly process is more streamlined. The assembly personnel only need to press the plug into the position to complete the assembly, significantly shortening the assembly cycle and reducing the labor cost; there is no need to machine additional structures such as tapered pin holes on the plug and the bearing ring, effectively reducing the processing procedures, reducing the complexity of the mold and the difficulty of numerical control programming, and is suitable for mass production.

[0026] (8) The overall heat treatment of the structure after the plug is assembled with the filling hole. Based on the special structural design of the plug and the filling hole, it can effectively adapt to the geometric changes during the heat treatment and processing. The plug fit has good tolerance compensation ability, showing higher qualification rate and reliability in actual manufacturing.

[0027] (9) The special design of the plug and the filling hole improves the modularity and standardization of the bearing structure, making it very suitable for integration into an automated assembly production line, which helps to improve the production efficiency and consistency of the robot or precision equipment industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic structural diagram of the outer ring of the bearing in this embodiment; Figure 2 is Figure 1 The partial enlarged schematic diagram of part A shown; Figure 3 It is a schematic structural diagram of the plug in this embodiment; Figure 4 is Figure 3 The axial projection schematic diagram of the plug shown; Figure 5 It is a schematic structural diagram of the assembled and turned outer ring of the bearing and the plug in this embodiment; Figure 6 is Figure 5 The sectional view taken along line B-B shown; Figure 7 is Figure 6 The partial enlarged schematic diagram of part D shown; Figure 8 is Figure 5 The partial enlarged schematic diagram of part C shown; Figure 9 It is a schematic process flow diagram of the manufacturing method of the crossed roller bearing in this embodiment. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0029] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0030] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "front", "rear", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0031] In the description of the present invention, it should be noted that unless otherwise clearly specified and defined, the terms "installation", "connection", and "coupling" should be understood in a broad sense. For example, it can be a fixed connection, an integral connection, or a detachable connection; it can be the communication inside two components; it can be directly connected or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0032] A manufacturing method of a crossed roller bearing according to this embodiment is as Figure 9 shown, and includes the following steps: S10: Preprocess the bearing ring and the plug 30, where the bearing ring and the plug 30 are made of the same material.

[0033] Among them, the structure of the plug 30 of this embodiment is as Figure 3 , Figure 4 shown, and includes a columnar section 31 and a lug structure 32 located at one end of the columnar section 31. A first positioning step 33 is formed between the columnar section 31 and the lug structure 32.

[0034] As a special feature of this embodiment, among them, as Figure 3 , Figure 4 shown, the projection of the lug structure 32 in the axial direction of the columnar section 31 is asymmetrically designed based on the axis of the columnar section 31. It should be noted that in this embodiment, no limitation is imposed on the specific shape of the asymmetry.

[0035] In this embodiment, taking the outer bearing ring 10 as an example, the structure of the bearing ring is described. Among them, as Figure 1 , Figure 2 shown, a loading hole 20 adapted to the plug 30 is provided on the outer bearing ring 10. Among them, the loading hole 20 includes a round hole 21 adapted to the columnar section 31 and a slot hole 22 adapted to the lug structure 32, and a second positioning step 12 adapted to the first positioning step 33 is formed between the slot hole 22 and the round hole 21.

[0036] As a special feature of this embodiment, among them, the lug structure 32 and the slot hole are in a small taper fit. Preferably, the taper angle α is 0.5°–7°.

[0037] Preferably, in this embodiment, as Figure 3 , Figure 4As shown, at least one flat surface 34 is provided in the circumferential direction of the lug structure. In this embodiment, four flat surfaces 34 are provided. Correspondingly, a flat surface structure adapted to the above flat surface 34 is provided on the circumferential wall of the slot hole 22. In this embodiment, the provision of the flat surface 34 increases the stability between the plug and the circumferential direction of the loading hole, effectively preventing rotational misalignment caused by vibration or operating shock.

[0038] S20: Pre-assembly. Press the plug 30 into the loading hole 20, and by upsetting the outer end surface of the lug structure 32 on the plug 30, make the lug structure 32 and the slot hole 22 in a slightly interference fit.

[0039] Preferably, in this embodiment, the interference amount between the lug structure 32 and the slot hole 22 is 5μm - 50μm.

[0040] S30: Rough machining, rough machine the inner ring surface and the outer ring surface of the assembly formed in S20 by turning. As Figures 5 - 8 shown, by rough machining with turning, a groove 11 for accommodating rollers is machined at the free end of the cylindrical section 31 of the plug 30.

[0041] In this embodiment, based on the interference fit between the lug structure and the slot hole and the axial positioning of the first positioning step and the second positioning step, during the rough machining process, the position of the plug in the loading hole is relatively stable and will not shift, and the machining accuracy is relatively high.

[0042] S40: Heat treatment, heat treat and harden the assembly obtained in S30 to obtain the required hardness. Among them, according to the functional requirements of the bearing, select an appropriate heat treatment process to heat treat the assembly composed of the plug and the bearing ring. It should be noted that this embodiment does not limit the specific heat treatment process, which is determined according to the material and application scenario requirements.

[0043] S50: Finish machining, finish machine the inner ring surface and the outer ring surface of the assembly obtained in S40 to the required precision. It should be noted that in this embodiment, the finish machining process can adopt a finish turning or finish grinding or a finish machining process combining finish turning and finish grinding. This embodiment does not limit its specific finish machining process.

[0044] S60: Assembly. In this embodiment, the assembly process at least includes the following steps: S61: Remove the plug 30 from the assembly obtained by finish machining in S50.

[0045] S62: Install the rollers and the spacer blocks into the grooves between the bearing inner ring and the bearing outer ring through the loading hole 20.

[0046] S63. After the roller and the spacer are installed, install the plug 30 into the filling hole 20.

[0047] S70: Welding. Weld and fix the plug 30 to the outer ring 10 of the bearing. Preferably, the welding process uses laser welding. After welding, the plug and the outer ring of the bearing form an integral body.

[0048] It should be noted that in this embodiment, the filling hole is set on the outer ring of the bearing as an example for illustration. Those skilled in the art should understand that the filling hole can also be set on the inner ring of the bearing.

[0049] A cross roller bearing of this embodiment is processed by the manufacturing method of the above cross roller bearing.

[0050] In summary, the above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A manufacturing method of a crossed roller bearing, characterized in that, It includes the following steps: S10: Pre-process the bearing ring and the plug, where the bearing ring and the plug are made of the same material; Among them, the plug includes a columnar section and a lug structure located at one end of the columnar section. A first positioning step is formed between the columnar section and the lug structure, and the projection of the lug structure in the axial direction of the columnar section is asymmetrically designed based on the axis of the columnar section; Among them, the bearing ring is provided with a loading hole adapted to the plug. The loading hole includes a round hole adapted to the columnar section and a slot hole adapted to the lug structure. A second positioning step adapted to the first positioning step is formed between the slot hole and the round hole; Among them, a small taper fit is formed between the lug structure and the slot hole; S20: Pre-assembly, press the plug into the loading hole, and by upsetting the outer end face of the lug structure on the plug, make the lug structure and the slot hole in a slightly interference fit; S30: Rough machining, rough machine the inner ring surface and the outer ring surface of the assembly formed in S20 by turning; S40: Heat treatment, perform heat treatment hardening on the assembly obtained in S30 to obtain the required hardness; S50: Finish machining, finish machine the inner ring surface and the outer ring surface of the assembly obtained in S40 to the required precision; S60: Assembly, at least includes the following steps: S61: Remove the plug from the assembly obtained by finish machining in S50; S62: Load the rollers and the spacer blocks into the raceway between the bearing inner ring and the bearing outer ring through the loading hole; S63: After the installation of the rollers and the spacer blocks is completed, install the plug into the loading hole; S70: Welding, weld and fix the plug and the bearing ring; 2. The manufacturing method according to claim 1, characterized in that, The interference amount between the lug structure and the slot hole is 5μm - 50μm.

3. The manufacturing method according to claim 1, characterized in that, The taper angle between the lug structure and the slot hole is 0.5° - 7°.

4. The manufacturing method according to claim 1, wherein The bearing ring provided with the loading hole is a bearing inner ring or a bearing outer ring.

5. The manufacturing method according to claim 1, characterized in that, At least one plane is provided in the circumferential direction of the lug structure.

6. The manufacturing method according to claim 1, characterized in that In S70, laser welding process is adopted for welding.

7. A cross roller bearing, characterized in that, It is processed by the manufacturing method according to any one of claims 1 - 6.

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