A machining process for a high-precision robot cross roller bearing integrated with a gear ring

Abstract

The application relates to the field of robot component processing, and discloses a high-precision robot gear ring integrated cross-roller bearing machining process. In the machining, a rough machining completed integrated blank is subjected to high-frequency local heat treatment process hardening treatment on a bearing raceway part by using a first clamp and a heating device, so that the hardness of the raceway is accurately controlled at HRC55-60; wherein the temperature of the gear ring part is less than or equal to 200 DEG C; in step five, the workpiece after the local heat treatment of the bearing raceway is subjected to high-precision semi-finishing machining, and the machining content includes an end face of the bearing part and an outer circle of the bearing part; a finishing machining allowance is reserved in the semi-finishing process, and the allowance contains a deformation compensation amount generated after gear part machining. The product adopting the machining process has the advantages of high precision, long service life and high strength.

Description

Technical Field

[0001] This invention relates to the field of robot component processing, and in particular to a high-precision machining process for an integrated cross roller bearing for robot gear rings. Background Technology

[0002] Crossed roller bearings, with their high precision and rigidity, are core components of high-end equipment and are widely used in applications with stringent requirements for rotational accuracy, structural rigidity, and transmission stability. Currently, the industry commonly uses a traditional "separate machining + subsequent assembly" approach for combining gear rings and crossed roller bearings. This involves independently machining the gear ring and crossed roller bearings, then connecting them using screws, interference fits, or other methods. However, with changing application scenarios and the demands of high-end equipment, especially robotics, this approach suffers from the following unavoidable technical drawbacks: 1. Uncontrollable assembly errors can easily lead to deviations in the concentricity of the gear ring and bearing raceway, directly reducing the overall rotational accuracy of the bearing and the meshing transmission accuracy of the gears, thus affecting the operational stability of the equipment. 2. The joint strength of the split connection structure is limited. Under harsh working conditions such as high-speed operation and strong impact, the connection is prone to loosening, which greatly shortens the service life of the bearing. If the interference fit press-fit process is used, the gear ring is very likely to fall off from the bearing body under strong impact conditions, which directly leads to equipment failure and poses a safety hazard. 3. The modular processing is cumbersome, requiring additional assembly and inspection steps, resulting in low processing efficiency and high assembly costs, which is not conducive to large-scale mass production.

[0003] To address the inherent defects of the aforementioned split structure, an attempt was made to develop an integrated machining process for the gear ring and crossed roller bearing. This involves machining a single base material as a whole to directly form an integrated structure of the crossed roller bearing with the gear ring. However, existing integrated machining technologies suffer from interference between the gear ring and bearing raceway during processing due to their high integration. Furthermore, the reliance on general machining and heat treatment processes has resulted in a lack of targeted technical solutions, leading to a series of key technical challenges, as follows: 1. The positioning of the gear part is difficult. During the machining of the integrated structure, the gear ring is prone to deformation, which causes deviations in the accuracy of the tooth profile and the tooth direction, and cannot meet the accuracy requirements of high-end equipment. 2. There is an essential difference in the heat treatment hardness requirements between the gear ring and the bearing raceway. Existing technology requires at least two heat treatments to achieve different hardness requirements. During the heat treatment process, the gear ring and the bearing raceway are prone to positional misalignment, and this misalignment cannot be corrected in subsequent processing, ultimately leading to excessive concentricity between the two. 3. The processing sequence is not planned reasonably. The teeth or bearing raceways that are processed first are easily disturbed during the processing of other parts in the subsequent process, making it difficult to maintain the accuracy of the processed parts and causing the overall accuracy to be lost.

[0004] A search revealed that current technologies lack a dedicated machining process for integrated gear ring and crossed roller bearing structures. This fails to effectively resolve the core contradiction between "high structural integration" and "end-to-end precision assurance," and also hinders the simultaneous improvement of tooth precision, overall rigidity, and machining efficiency. Therefore, there is an urgent need to develop a machining process for integrated gear ring and crossed roller bearings that can simultaneously guarantee tooth precision, bearing raceway precision, and overall assembly precision to meet the application requirements of high-end equipment. Summary of the Invention

[0005] This invention addresses the current lack of a dedicated machining process for integrated gear ring and crossed roller bearing structures in existing technologies. This process fails to effectively resolve the core contradiction between "high structural integration" and "end-to-end precision assurance," and also fails to simultaneously improve tooth precision, overall rigidity, and machining efficiency. Therefore, the inventors have creatively designed a high-precision machining process for integrated gear ring and crossed roller bearings used in robots.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution: A high-precision machining process for an integrated cross roller bearing for robots includes an integrally formed gear ring portion and a bearing portion, which are coaxially arranged. The bearing portion is located at the end of the gear ring portion, and the gear ring portion has an internal gear ring structure. The bearing portion has a first cavity inside, which is connected to the inside of the gear ring portion. The outer ring of the bearing portion has a raceway for mounting rollers. The processing technology includes the following steps: Step 1: Select 42CrMo alloy structural steel as the base material for integrated processing; first, use hot forging to process the base material into a blank, and then perform normalizing treatment at a temperature of 860-880℃, hold for 2 hours, and air cool to room temperature. Step 2: After normalizing, the blank is subjected to quenching and tempering heat treatment. First, the quenching temperature is 840℃, held for 1.5 hours, and then oil-cooled to room temperature; then the tempering temperature is 580℃, held for 3 hours, and then air-cooled. Step 3: Perform rough machining on a CNC lathe on the tempered blank to complete the initial shape of the integrated bearing and reserve machining allowance; the outer diameter of the bearing part is reserved by 3-4mm, and the teeth of the gear ring part are reserved by 2-3mm; during the machining process, high-precision measuring instruments are used to detect the outer dimensions in real time to ensure that the rough machining dimension deviation is within ±0.04mm. Step 4: For the integrated blank part that has been rough-machined, use the first fixture and heating device to perform high-frequency local heat treatment hardening process on the bearing raceway part, and accurately control the raceway hardness to HRC55-60; the temperature of the gear ring part is ≤200℃. Step 5: Perform high-precision semi-finish grinding on the workpiece after local heat treatment of the bearing raceway. The machining includes the end face of the bearing part and the outer circle of the bearing part. During the semi-finish grinding process, a fine grinding allowance is reserved, and the allowance includes the deformation compensation amount generated after the gear part is machined. Step 6: Perform precision grinding on the gear ring, controlling the tooth accuracy to level 7 or above; Step 7: After the gear machining is completed, the integrated bearing is precision ground to achieve the final precision forming of the bearing raceway, end face, and outer circle.

[0007] Preferably, in steps five, six, and seven, the end face of the bearing portion is used as the first reference surface, and the outer ring of the bearing portion is used as the second reference surface.

[0008] Preferably, the first clamp includes a fixed base, the fixed base includes a base plate and an annular sleeve on the base plate, the inner ring of the annular sleeve is a second cavity, the upper end face of the annular sleeve is provided with a downwardly extending assembly groove, the assembly groove divides the annular sleeve into an outer ring and an inner ring, the outer side surface of the inner ring is provided with a tooth groove that mates with the tooth of the toothed ring, and the inner side surface of the outer ring fits against the outer side surface of the toothed ring.

[0009] Preferably, the device also includes a heating device, which includes a heating ring distributed on the outside of the channel. The heating ring is an induction coil heating device.

[0010] Preferably, the upper side of the outer ring is provided with a high-temperature resistant ceramic protective edge, and the outer side of the outer ring is provided with multiple sets of heat dissipation grooves. The fitting gap between the outer side of the toothed ring and the inner side of the outer ring is less than or equal to 0.015mm, and the fitting gap between the tooth and the tooth groove of the toothed ring is less than or equal to 0.02mm.

[0011] Preferably, in step six, the tooth machining tool for the gear ring includes a cylindrical tool holder and a toothed tool body located at the lower end of the tool holder. The tool body is a frustum-shaped shape with a smaller upper part and a larger lower part, and multiple toothed cutting edges are provided on the circumferential side of the tool body. The toothed cutting edges adopt a double pressure angle design with parameters of a working pressure angle of 20°, a non-working pressure angle of 15°, and a tooth tip radius of R0.3mm. The cutting edge parameters are a rake angle of 11°, a top edge clearance angle of 8°, and a cutting edge chamfer of 0.05×45°. The tool body is coated with a TiAIN coating with a thickness of 3μm.

[0012] As a preferred option, the allowance for precision grinding is specifically 0.04-0.06mm for the outer diameter of the bearing part and 0.03-0.05mm for the end face height of the bearing part; the flatness of the end face of the workpiece is ≤0.002mm and the runout of the outer diameter is ≤0.002mm through semi-precision grinding.

[0013] Because the present invention adopts the above technical solution, it has the following significant technical effects: The innovation of this solution lies in the following effects achieved through the above process: Compared with the prior art, the processing technology of this invention has outstanding substantive features and significant progress. All effects can be quantitatively verified through actual test data, as detailed below: 1. Significantly improved accuracy, effectively resolving core contradictions. Through collaborative innovation of "unified benchmark positioning, local heat treatment protection, and precise process planning," key technical problems such as tooth deformation, concentricity deviation, easy loss of precision, and hardness conflict between the tooth and raceway in existing integrated machining have been completely solved. The machining accuracy of the HZC327523 integrated gear ring bearing has been stably achieved to level 7, which is 2 levels higher than the traditional split machining process. The concentricity deviation between the gear ring and the bearing raceway is controlled within 0.005mm, and the overall rotational accuracy of the bearing is ≤0.003mm, meeting the stringent requirements of high-end robots and precision machine tools, and filling the gap in the existing technology of "dedicated machining process for integrated structures".

[0014] 2. Enhanced structural rigidity significantly improves adaptability to various working conditions. The integrated molding structure of the gear ring and crossed roller bearing completely eliminates the connection gap of traditional separate assembly. For the HZC327523 bearing, the overall structural rigidity is increased by more than 50% compared with the separate assembly structure. Under harsh working conditions of heavy load, high speed and strong impact, the bearing's operating stability is greatly improved, with no risk of interference fit failure or loose connection. The service life is extended by more than 30% compared with the separate structure, significantly improving the operational reliability of high-end equipment.

[0015] 3. Improved processing efficiency and significantly reduced manufacturing costs The integrated processing technology directly eliminates the cumbersome process of traditional "separate processing + assembly + assembly inspection", greatly simplifying the production process and increasing processing efficiency by 30%. At the same time, it eliminates the need for additional assembly parts and assembly labor costs, reducing the overall manufacturing cost by 20%, and has significant economic benefits for large-scale mass production, solving the pain points of "low efficiency and high cost" of traditional processes.

[0016] 4. Highly adaptable and widely applicable. The process design, parameter control, and fixture matching of this technology are universal, and it can be adapted to the integrated machining of gear ring-crossed roller bearings of different specifications and tooth profiles. The machining accuracy is stable and controllable. It can be widely used in high-end equipment fields such as industrial robots, precision machine tools, aerospace precision instruments, and CNC rotary tables, which have high requirements for bearing accuracy, rigidity, and reliability. It has strong practicality and broad market application prospects. Attached Figure Description

[0017] Figure 1 This is a structural diagram of the product.

[0018] Figure 2 yes Figure 1 A sectional view.

[0019] Figure 3 This is a schematic diagram of the first fixture.

[0020] Figure 4 This is a schematic diagram showing the combination of the product, the first fixture, and the heating device.

[0021] Figure 5 This is a schematic diagram of the cutting tool.

[0022] Figure 6 Example 2 is a schematic diagram showing the cooperation between the product, the first clamp, and the heating device.

[0023] Figure 7 Example 3 is a schematic diagram showing the cooperation between the product, the first clamp, and the heating device.

[0024] The reference numerals in the figure represent the following technical features: 1—gear ring, 2—bearing part, 3—end face, 4—first cavity, 5—raceway, 6—outer ring, 7—base plate, 8—annular sleeve, 9—second cavity, 10—assembly groove, 11—outer ring, 12—inner ring, 13—gear groove, 14—heating device, 15—protective edge, 16—tool handle, 17—tool body, 18—blade, 19—first reference surface, 20—second reference surface. Detailed Implementation

[0025] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments.

[0026] Example 1 In response to the above problems, the inventors disclosed the following process to solve the aforementioned technical issues.

[0027] like Figure 1 and Figure 2 As shown, a high-precision robotic integrated gear ring crossed roller bearing manufacturing process includes an integrally formed gear ring portion 1 and a bearing portion 2, which are coaxially arranged. The bearing portion 2 is located at the end of the gear ring portion 1. The gear ring portion 1 has an internal gear ring structure. The bearing portion 2 has a first cavity 4 inside, which communicates with the inside of the gear ring portion 1. The outer ring 6 of the bearing portion 2 has raceways 5 for mounting rollers. The outer surface of the bearing portion 2 serves as the inner ring of the bearing, and the raceways are used to mate with the outer ring 6 of the bearing to mount rollers. The specific manufacturing process of this integrated gear ring structure is as follows.

[0028] This embodiment takes the inventor's product model HZC327523 high-precision cross roller bearing for robot joints with internal gear ring as an example. The bearing has an inner diameter of 32mm, an outer diameter of 75mm, and a width of 23mm. It is suitable for the rotary joints of humanoid robots and quadruped robots. The requirements are that the precision of tooth 21 is grade 7, the hardness of raceway 5 is HZC55-60, the hardness of tooth 21 is HRC25-30, and the concentricity between the gear ring and raceway 5 is ≤0.005mm.

[0029] The processing technology includes the following steps: Step 1: Select 42CrMo alloy structural steel as the base material for integrated machining. This material combines the wear resistance of gear rings with the fatigue and impact resistance of bearings, meeting the comprehensive performance requirements of integrated structures. First, use hot forging to process the base material into a blank. After forging, normalize it at a temperature of 860-880℃ for 2 hours, then air cool it to room temperature. This completely eliminates the internal stress generated during forging. The internal stress value after normalizing is ≤80MPa to prevent deformation during subsequent machining. Step 2: After normalizing, the blank is subjected to quenching and tempering heat treatment. First, the quenching temperature is 840℃, held for 1.5 hours, and then oil-cooled to room temperature; the tempering temperature is 580℃, held for 3 hours, and then air-cooled. The hardness of the base material is precisely controlled at HRC25-30, which not only meets the hardness requirements of the gear ring, but also avoids the increased difficulty of subsequent machining and excessive tool wear due to excessive hardness.

[0030] Step 3: Rough turning of the tempered blank on a CNC lathe to complete the initial shape of the integrated bearing and leave machining allowance; the outer diameter of bearing part 2 is reserved by 3-4mm, and the tooth 21 of gear ring part 1 is reserved by 2-3mm; during the machining process, high-precision measuring instruments are used to detect the outer dimensions in real time to ensure that the rough machining dimensional deviation is within ±0.04mm; laying the precision foundation for subsequent processes. Step 4: After rough machining, the blank needs to be finished. Since the bearing section 2 and gear ring section 1 have different required parameters, their heat treatment methods are also different. Furthermore, to ensure consistent positioning and avoid the earlier heat treatment affecting the later heat treatment of gear section 21, this solution involves the following steps for heat treatment and finishing: Specifically, for the integrated blank after rough machining, the bearing raceway 5 is subjected to high-frequency local heat treatment hardening using the first fixture and heating device 14, precisely controlling the hardness of raceway 5 to HRC55-60; the temperature of gear ring section 1 is ≤200℃. To achieve successful heating of this part in one go without affecting the performance of the gear ring 1, the inventors developed a positioning device and a heating device 14 to achieve this goal, such as... Figure 3 and Figure 4 As shown, specifically: The first fixture includes a fixed base, which is a circular plate with multiple fixing holes for fixing to other components. The fixed base includes a base plate 7 and an annular sleeve 8 on the base plate 7. The inner ring of the annular sleeve 8 is a second cavity 9. The upper end face 3 of the annular sleeve 8 has a downwardly extending assembly groove 10, which divides the annular sleeve 8 into an outer ring 11 and an inner ring 12. The outer surface of the inner ring 12 has a toothed groove 13 that meshes with the teeth 21 of the gear ring 1. The inner surface of the outer ring 11 fits against the outer surface of the gear ring 1. The annular sleeve 8 functions to position the workpiece and simultaneously contacts the gear ring on both sides. With the help of the fixed base, the heat dissipation efficiency of the gear ring 1 is greatly accelerated. This prevents the gear ring 1 from exceeding 200°C during the heating of the raceway 5 of the bearing 2. In this design, for ease of processing, the first fixture is made of 45# steel with a heat treatment process of HRC25-32. Clearly, the raceway 5 protrudes outside the annular sleeve 8, facilitating contact with the heating element for heating. The first clamp facilitates heat dissipation from the gear ring 1 and also ensures the positional relationship between the raceway 5 and the heating element, guaranteeing consistent heating across the raceway 5 and ensuring product consistency. In this design, the heating device 14 includes a heating ring distributed on the outer side of the raceway, and the heating ring is an induction coil heating device 14.

[0031] To further isolate the radiant heat from induction heating and prevent the heat from the raceway 5 from spreading to the gear ring, a high-temperature resistant ceramic protective edge 15 is provided on the upper side or / and the upper end of the outer side of the outer ring 11. Multiple sets of heat dissipation grooves are provided on the outer side of the outer ring 11. The fitting gap between the outer side of the gear ring 1 and the inner side of the outer ring 11 is less than or equal to 0.015 mm, and the fitting gap between the tooth 21 of the gear ring 1 and the tooth groove 13 is less than or equal to 0.02 mm.

[0032] This solution differs from the existing "overall heat treatment + secondary processing" model. This step uses a special positioning fixture to ensure the position of the blank is fixed, and a customized copper heat absorption device is added to provide heat insulation protection for position 1 of the gear ring. The heating area is strictly limited to the bearing raceway 5, ensuring that the temperature of position 1 of the gear ring is ≤200℃. This prevents heat from affecting the gear ring and causing its hardness to rise abnormally, thus avoiding the inability to achieve mass production efficiency in the subsequent processing of gear 21. This effectively solves the technical problem of "hardness conflict between gear 21 and raceway 5".

[0033] Step 5: Perform high-precision semi-finish grinding on the bearing raceway 5 after local heat treatment. The machining includes the end face 3 of the bearing part 2 and the outer circle of the bearing part 2. During the semi-finish grinding process, a finishing machining allowance is reserved, and the allowance includes the deformation compensation amount generated after the machining of the gear part 21. Specific allowance parameters: outer circle allowance 0.04-0.06mm, end face 3 height allowance 0.03-0.05mm. Through semi-finish grinding, the high-precision forming of the workpiece shape is achieved. The flatness of the end face 3 is ≤0.002mm, and the outer circle runout is ≤0.002mm, providing a precise and stable positioning reference for the machining of the gear part 21.

[0034] Step 6: Perform precision grinding on the gear ring 1, and control the precision of the gear 21 to level 7 or above. To achieve this precision, the inventors designed a cutting tool and machining process. This tool, in conjunction with a Y5132 gear shaper, performs precision grinding of the gear ring. Through tool optimization, parameter design, and fixture matching, the precision control of the gear section 21 is achieved. Specific requirements are as follows: Figure 5 As shown: a. The cutting tool is a carbide gear shaper. The surface of the tool body 17 is treated with a TiAlN coating with a coating thickness of 3μm and a coating hardness of HV2800, which improves the surface hardness, wear resistance and anti-adhesion of the tool. The wear status of the cutting edge is monitored in real time during the processing. When the wear is ≥0.01mm, the tool is replaced or re-grinded in time to avoid the decrease in tooth profile accuracy due to tool wear. b. Optimized design of tool body parameters 17: The rake angle is set to 10°-12°, the back angle of the top cutting edge is set to 7°-9°, and a double pressure angle structure is adopted with a working pressure angle of 20° and a non-working pressure angle of 15°. The cutting flow field is optimized to reduce the extrusion deformation of the tooth blank during the cutting process and ensure the accuracy of the tooth profile.

[0035] Specifically, the toothed part 21 of the gear ring part 1 includes a columnar tool holder 16 and a toothed tool body 17 located at the lower end of the tool holder 16. The tool body 17 is a frustum-shaped shape with a smaller upper part and a larger lower part. Multiple toothed cutting edges 18 are provided on the circumferential side of the tool body 17. ① Tool body 17: Made of solid carbide, the tool body 17 has a diameter of ∅80mm and a length of 120mm, and the tool holder 16 has a diameter of ∅32mm, which is compatible with the spindle of the Y5132 gear shaping machine.

[0036] ② The tooth shape of the toothed blade 18: adopts a double pressure angle design, with a working pressure angle of 20° and a non-working pressure angle of 15°, and a tooth tip radius of R0.3mm to avoid tooth tip breakage.

[0037] ③ Cutting edge: Rake angle 11°, top edge clearance angle 8°, cutting edge chamfer 0.05×45°, to improve cutting sharpness and reduce chip force.

[0038] ④ Coating: Surface TiAIN coating, 3μm thick, uniformly covers the cutting edge and tooth surface, with a coating hardness of HC2800 and an adhesion of ≥100N; c. Positioning fixture matching: The positioning fixture is adopted, with the semi-finished bearing outer ring and bearing 2 end face 3 as the sole positioning reference. The positioning accuracy of the fixture itself is ≤0.002mm, and the workpiece runout after clamping is ≤0.002mm, ensuring the positioning accuracy of the gear 21 machining and avoiding positioning deviation that causes the concentricity of the gear ring and raceway 5 to exceed the tolerance. d. Gear shaping process parameters: Based on the material properties of 42CrMo and the precision requirements of tooth 21, a suitable cutting speed of 12m / min, a feed rate of 0.08mm / tooth, and a cutting depth of 0.3mm are matched and fed in 8 batches to achieve efficient and precise machining of tooth 21.

[0039] Step 7: After the tooth 21 is machined, the integrated bearing is precision ground to achieve the final precision forming of the bearing raceway 5, end face 3, and outer circle. The core technical points are: the semi-precision grinding, tooth 21 machining, and precision grinding all use the same positioning datum, namely the outer circle of bearing part 2 + the end face 3 of bearing part 2. This differs from the "multi-datum switching" machining mode in existing technologies, avoiding machining deviations caused by datum switching. It ensures that the precision of the previously machined tooth 21 and raceway 5 is not damaged during precision grinding, achieving a high-precision concentricity of the gear ring and bearing raceway 5 ≤ 0.005mm, guaranteeing the overall rotational accuracy of the integrated bearing.

[0040] That is, in steps five, six and seven, the end face 3 of the bearing part 2 is used as the first reference surface 19 and the outer ring 6 of the bearing part 2 is used as the second reference surface 20.

[0041] The outer ring 11 has a high-temperature resistant ceramic protective edge 15 on its upper side and multiple heat dissipation grooves on its outer side. The fitting gap between the outer side of the toothed ring 1 and the inner side of the outer ring 11 is less than or equal to 0.015 mm, and the fitting gap between the tooth 21 of the toothed ring 1 and the tooth groove 13 is less than or equal to 0.02 mm.

[0042] Compared with the prior art, the processing technology of this invention has outstanding substantive features and significant progress. All effects can be quantitatively verified through actual test data, as detailed below: 1. Significantly improved accuracy, effectively resolving core contradictions. Through collaborative innovation of "unified benchmark positioning, local heat treatment protection, and precise process planning," key technical problems such as deformation of tooth 21, excessive concentricity, easy loss of precision, and hardness conflict between tooth 21 and raceway 5 in existing integrated machining have been completely solved. The machining accuracy of tooth 21 of HZC327523 integrated gear ring bearing has been stably achieved to level 7, which is 2 levels higher than the traditional split machining process. The concentricity deviation between the gear ring and the bearing raceway 5 is controlled within 0.005mm, and the overall rotational accuracy of the bearing is ≤0.003mm, which meets the stringent requirements of high-end robots and precision machine tools and fills the gap in the existing technology of "dedicated machining process for integrated structure".

[0043] 2. Enhanced structural rigidity significantly improves adaptability to various working conditions. The integrated molding structure of the gear ring and crossed roller bearing completely eliminates the connection gap of traditional separate assembly. For the HZC327523 bearing, the overall structural rigidity is increased by more than 50% compared with the separate assembly structure. Under harsh working conditions of heavy load, high speed and strong impact, the bearing's operating stability is greatly improved, with no risk of interference fit failure or loose connection. The service life is extended by more than 30% compared with the separate structure, significantly improving the operational reliability of high-end equipment.

[0044] 3. Improved processing efficiency and significantly reduced manufacturing costs The integrated processing technology directly eliminates the cumbersome process of traditional "separate processing + assembly + assembly inspection", greatly simplifying the production process and increasing processing efficiency by 30%. At the same time, it eliminates the need for additional assembly parts such as screws and positioning pins, as well as assembly labor costs, reducing the overall manufacturing cost by 20%. It has significant economic benefits for large-scale mass production and solves the pain points of "low efficiency and high cost" of traditional processes.

[0045] 4. Highly adaptable and widely applicable. This process features versatile process design, parameter control, and fixture matching, making it suitable for integrated machining of gear ring-crossed roller bearings of different specifications and tooth profiles, including spur and helical teeth. The machining accuracy is stable and controllable. It can be widely applied in high-end equipment fields such as industrial robots, precision machine tools, aerospace precision instruments, and CNC rotary tables, where high precision, rigidity, and reliability of bearings are required. It is highly practical and has broad market application prospects. Example 2 The difference from Example 1 is that: Figure 6 As shown, the upper side and the upper end of the outer side of the outer ring 11 are provided with a high-temperature resistant ceramic protective edge 15 with a width of 3mm, which does not affect the overall heat dissipation and can isolate the heat close to the heating device 14.

[0046] Example 3 The difference from Example 1 is that: Figure 7As shown, the upper end of the outer side of the outer ring 11 is provided with a high-temperature resistant ceramic protective edge 15, which is 3mm wide. This does not affect the overall heat dissipation and can also isolate the heat from the heating device 14.

Claims

1. A high-precision machining process for an integrated cross roller bearing for robot gear rings, characterized in that: It includes an integrally formed gear ring portion (1) and a bearing portion (2), the gear ring portion (1) and the bearing portion (2) are arranged on the same axis, the bearing portion (2) is located at the end of the gear ring portion (1), the gear ring portion (1) is an internal gear ring structure, the bearing portion (2) has a first cavity (4) inside, the first cavity (4) and the interior of the gear ring portion (1) are connected; the outer ring (6) of the bearing portion (2) has a raceway (5) for mounting rollers; The processing technology includes the following steps: Step 1: Select 42CrMo alloy structural steel as the base material for integrated processing; first, use hot forging to process the base material into a blank, and then perform normalizing treatment at a temperature of 860-880℃, hold for 2 hours, and air cool to room temperature. Step 2: After normalizing, the blank is subjected to quenching and tempering heat treatment. First, the quenching temperature is 840℃, held for 1.5 hours, and then oil-cooled to room temperature; then the tempering temperature is 580℃, held for 3 hours, and then air-cooled. Step 3: Perform rough machining on a CNC lathe on the tempered blank to complete the initial shape of the integrated bearing and reserve machining allowance; the outer circle of the bearing part (2) is reserved by 3-4mm, and the tooth part of the gear ring part (1) is reserved by 2-3mm; during the machining process, a high-precision detection instrument is used to detect the outer dimensions in real time to ensure that the rough machining dimension deviation is within ±0.04mm. Step 4: For the integrated blank that has been rough-machined, use the first fixture and heating device (14) to perform high-frequency local heat treatment hardening process on the bearing raceway (5) to accurately control the hardness of the raceway (5) to HRC55-60; wherein the temperature of the gear ring (1) part during the heating process is ≤200℃. Step 5: Perform high-precision semi-finish grinding on the workpiece after local heat treatment of the bearing raceway (5). The processing includes the end face (3) of the bearing part (2) and the outer circle of the bearing part (2). During the semi-finish grinding process, a fine grinding allowance is reserved, and the allowance includes the deformation compensation amount generated after the tooth processing. Step 6: Perform precision grinding on the gear ring (1), and control the precision of the gears to level 7 or above. Step 7: After the gear part is processed, the integrated bearing is precision ground to complete the final precision forming of the bearing raceway (5), end face (3) and outer circle.

2. The machining process for a high-precision robot gear ring integrated crossed roller bearing according to claim 1, characterized in that: In steps five, six and seven, the end face (3) of the bearing part (2) is used as the first reference surface (19), and the outer ring (6) of the bearing part (2) is used as the second reference surface (20).

3. The machining process for a high-precision robot gear ring integrated crossed roller bearing according to claim 1, characterized in that: The first fixture includes a fixed base, which includes a base plate (7) and an annular sleeve (8) on the base plate (7). The inner ring of the annular sleeve (8) is a second cavity (9). The upper end face (3) of the annular sleeve (8) is provided with a downwardly extending assembly groove (10). The assembly groove (10) divides the annular sleeve (8) into an outer ring (11) and an inner ring (12). The outer side surface of the inner ring (12) is provided with a tooth groove (13) that mates with the tooth of the toothed part (1). The inner side surface of the outer ring (11) is in contact with the outer side surface of the toothed part (1).

4. The machining process for a high-precision robot gear ring integrated crossed roller bearing according to claim 3, characterized in that: It also includes a heating device (14), which includes a heating ring distributed on the outside of the channel. The heating ring is an induction coil heating device (14).

5. The machining process for a high-precision robot gear ring integrated crossed roller bearing according to claim 3, characterized in that: The upper side of the outer ring (11) is provided with a high-temperature resistant ceramic protective edge (15), and the outer side of the outer ring (11) is provided with multiple heat dissipation grooves. The fitting gap between the outer side of the toothed ring (1) and the inner side of the outer ring (11) is less than or equal to 0.015 mm, and the fitting gap between the tooth of the toothed ring (1) and the tooth groove (13) is less than or equal to 0.02 mm.

6. The machining process for a high-precision robot gear ring integrated crossed roller bearing according to claim 1, characterized in that: In step six, the tooth machining tool of the gear ring part (1) includes a columnar tool holder (16) and a toothed tool body (17) located at the lower end of the tool holder (16). The tool body (17) is a frustum shape with a smaller upper part and a larger lower part. Multiple toothed cutting edges (18) are provided on the circumferential side of the tool body (17). The toothed cutting edges (18) adopt a double pressure angle design with parameters of 20° working pressure angle, 15° non-working pressure angle, and R0.3mm tooth tip radius. The cutting edge parameters are 11° front angle, 8° back angle of the top edge, and 0.05×45° chamfer on the cutting edge. The tool body (17) is coated with TiAIN coating with a thickness of 3μm.

7. The machining process for a high-precision robot gear ring integrated crossed roller bearing according to claim 1, characterized in that: The allowance for precision grinding is specifically 0.04-0.06mm for the outer diameter of the bearing part (2) and 0.03-0.05mm for the height of the end face (3) of the bearing part (2); the flatness of the end face (3) of the workpiece is ≤0.002mm and the runout of the outer diameter is ≤0.002mm through semi-precision grinding.

8. The machining process for a high-precision robot gear ring integrated crossed roller bearing according to claim 1, characterized in that: In step six, a gear shaper is used to complete the precision grinding of the gear ring. The specific processing requirements are as follows: a. Carbide gear shaper cutters are used, and the tool surface is treated with TiAlN coating. b. Tool parameter optimization design: the rake angle is set to 10°-12°, the top edge clearance angle is set to 7°-9°, and a double pressure angle structure design is adopted with a working pressure angle of 20° and a non-working pressure angle of 15°. c. Positioning fixture matching: The outer ring (6) of the bearing part that has been semi-finished is used as the second reference surface (20), and the end face (3) of the bearing part (2) is used as the first reference surface (19) for positioning. The positioning accuracy of the fixture is ≤0.002mm, and the runout of the workpiece after clamping is ≤0.002mm. d. Gear shaping process parameters: cutting speed 12m / min, feed rate 0.08mm / tooth and cutting depth 0.3mm, fed in 8 passes.

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