Preparation process of non-standard thin-walled bearing and cross-roller bearing

Abstract

The application discloses a preparation process of a non-standard thin-wall bearing and a cross-roller bearing and relates to the technical field of harmonic reducers.The preparation process comprises the following steps: S1, blank forming;S2, normalizing treatment;S3, rough turning;S4, structure processing;S5, quenching processing;S6, hardness detection;S7, fine turning;S8, grinding processing;S9, groove grinding;S10, pin hole fine processing;S11, assembly and debugging; and S12, final inspection and packaging.The preparation process of the non-standard thin-wall bearing is characterized in that, before heat treatment is performed on the inner ring, a bottom hole with a diameter smaller than that of a finished pin hole is pre-drilled at the position of the pin hole; after the heat treatment and all grinding processes are completed, the hole is expanded and fine processed to the size of the finished pin hole, so that the adverse effect of heat treatment deformation on the precision of the pin hole is effectively avoided, the qualified rate of the finished product and the assembly precision are improved, the subsequent fine processing allowance is reduced, and the overall machining efficiency is improved.

Description

Technical Field

[0001] This invention relates to the field of harmonic reducer technology, to harmonic reducer transmission devices, and particularly to the manufacturing process of non-standard thin-walled bearings and crossed roller bearings. Background Technology

[0002] Harmonic reducers, as crucial components in modern industrial transmission, possess significant advantages such as small size, light weight, large transmission ratio, high precision, and strong load-bearing capacity. Among these advantages, a design integrating crossed roller bearings and rigid wheels has been proposed, achieving both compact structure and high transmission precision.

[0003] In emerging applications such as embodied intelligent robots and collaborative robots, there are higher requirements for the lightweight design of harmonic reducers. To further reduce weight and improve transmission efficiency, existing technologies often design the inner ring as a thin-walled structure while retaining precision features such as the tooth surface and pin holes. However, in the manufacturing process, a process of drilling, heat treatment, and grinding is usually adopted. The thin-walled structure is prone to deformation during heat treatment and grinding, making it difficult to guarantee the accuracy of the tooth surface and the position of the pin holes, thus affecting the overall assembly accuracy and transmission performance.

[0004] To improve the positional accuracy of pin holes, deformation is typically reserved during drilling, which is then corrected through subsequent grinding. However, the deformation of thin-walled structures after heat treatment is random, and the reserved amount is difficult to control precisely, making it difficult to keep the pin hole positional deviation within the preset range. Furthermore, if a finishing process is added after heat treatment, the high overall hardness makes machining difficult, causes severe tool wear, and easily generates microcracks, affecting the service life and reliability of the bearing. Summary of the Invention

[0005] The technical problem to be solved by this invention is that in the prior art, the pin hole position of thin-walled bearings is difficult to control accurately after heat treatment and the processing is difficult. This invention provides a manufacturing process for non-standard thin-walled bearings. Before heat treatment of the bearing rings, a bottom hole with a diameter smaller than the finished pin hole diameter is pre-drilled at the pin hole position. After heat treatment and all grinding processes are completed, the bottom hole is finally enlarged and finished to the finished pin hole size, thus completely eliminating the influence of thermal deformation on the position.

[0006] The technical solution adopted by this invention to solve its technical problem is: a manufacturing process for a non-standard thin-walled bearing, comprising the following steps: S1: Bearing blank forming: Outer ring blank, inner ring blank and plug blank are manufactured by forging process; S2: Normalizing treatment: The outer ring blank, inner ring blank and plug blank are normalized separately to eliminate internal stress, refine grains and improve the stability of subsequent processing; S3: Rough turning: Rough turning is performed on the outer ring blank, inner ring blank and plug blank to initially shape them and leave room for finishing. S4: Structural machining: Machining the inter-hole structural features of the outer ring blank, inner ring blank, and plug blank; S5: High-frequency induction hardening: Segmented hardening of outer ring blank, inner ring blank and plug blank; S6: Hardness test: Perform hardness test on each billet after quenching to ensure that the hardness meets the design requirements; S7: Finish turning: Finish turning is performed on outer and inner ring blanks with qualified hardness; this reduces the machining allowance and machining time of the grinding machine and improves work efficiency. S8: Grinding process: Perform internal and external cylindrical grinding on the outer ring blank and the inner ring blank to make its inner diameter, outer diameter and roughness meet the requirements of the finished product; S9: Raceway grinding: High-precision CNC raceway grinding machine is used to precisely grind the raceways of the outer ring blank, inner ring blank and plug blank; S10: Pin hole finishing: Perform pin hole finishing on the inner ring that has been quenched and has had its grooves ground. S11: Assembly and Adjustment: Precision assembly of the outer ring, inner ring, plug and roller, and adjustment of preload and rotational accuracy. S12: Final Inspection and Packaging: Perform full-size inspection, vibration and noise testing, and sealing verification on the assembled bearings. Qualified products are then subjected to rust prevention treatment, vacuum packaging, and warehousing.

[0007] Therefore, this invention adopts a process route of first pre-drilling the pilot hole and then finishing the pin hole. The high-frequency induction hardening is carried out in stages to ensure that the hardness of key parts such as the pilot hole and the tooth surface does not exceed 30HRC, which provides good machinability for subsequent finishing. At the same time, the pilot hole is retained as a position reference after heat treatment deformation, which can accurately correct the position deviation during the final hole enlargement and ensure that the pin hole position meets the design requirements.

[0008] Furthermore, in step S3, the inner ring blank is rough-machined to obtain a rough outline, leaving allowance for subsequent machining. That is, the groove and tooth surface are rough-machined with allowance, the tooth surface is not machined to the final tooth shape for the time being, and after the groove is rough-machined, a finishing allowance of 0.5-0.8mm is left on each side.

[0009] Furthermore, in step S4, a pilot hole is pre-drilled at the position corresponding to the pin hole of the inner ring blank; the diameter of the pilot hole is 0.3 to 0.7 mm smaller than the diameter of the final pin hole, preferably 0.5 mm; thereby, a hole enlargement allowance is reserved to compensate for subsequent thermal deformation, ensuring that the deformation is controllable at high frequencies, and indirectly reducing tool wear during subsequent precision drilling of the pin hole.

[0010] Furthermore, in step S5, an improved high-frequency quenching device is used to perform segmented quenching on the outer ring blank and the inner ring blank, so that different parts of them obtain different hardness distributions. The hardness of the pin hole area and tooth surface area of ​​the inner ring blank is controlled below 30HRC, which provides good cutting performance and dimensional stability for subsequent processing.

[0011] Furthermore, the improved high-frequency quenching device includes a quenching unit, a cooling unit, and a positioning unit. The quenching unit is used to heat the billet in sections. The cooling unit uses water cooling to rapidly cool the heated area and is used to rapidly cool the heated billet. The positioning unit is used to gradually move the billet to the quenching station. The quenching unit includes an induction coil and a magnetic conductor. The induction coil is a ring structure with a rectangular cross-section, and the axial thickness of the induction coil is less than the axial width of the channel. The magnetic conductor partially covers the outside of the induction coil to maintain the shape of the induction coil and enhance its magnetic field concentration.

[0012] Furthermore, the vertical cross-section of the magnetic conductor is U-shaped, with the U-shaped opening facing outwards. The induction coil is embedded in the U-shaped groove of the magnetic conductor, and the thickness of the upper horizontal arm of the magnetic conductor is greater than that of the lower horizontal arm. This thickness difference naturally creates an axial magnetic field gradient that is stronger at the bottom and weaker at the top, allowing for continuous zoned quenching without complex control. When the workpiece first enters the workstation, its top end face faces the lower layer's strong axial leakage magnetic field zone, prioritizing end face quenching. As the workpiece continues to move upwards, the outer cylindrical surface enters the effective radial heating zone of the coil, completing sidewall quenching. Simultaneously, due to the extremely weak leakage magnetic field in the upper layer, the heating intensity rapidly decays, preventing overheating of the already quenched area and avoiding contact with the inner wall's quench-avoidance zone.

[0013] Furthermore, the horizontal cross-section of the magnetic conductor is C-shaped, and the positive and negative poles of the induction coil are located within the C-shaped opening of the magnetic conductor.

[0014] Furthermore, both the upper and lower surfaces of the magnetic conductor are conical structures, with the taper directions of the upper and lower surfaces being opposite, and the upper and lower surfaces forming an angle α, the value of which is in the range of 15° to 20°; thereby achieving three functions: converging and controlling the direction of the magnetic field, changing the current distribution, and improving efficiency and heating uniformity.

[0015] Furthermore, the cooling unit includes a central spray assembly, a peripheral spray assembly, a liquid supply assembly, and a recovery assembly. The central spray assembly is located inside the induction coil and is movably arranged along the axial direction of the induction coil. The input end of the central spray assembly is connected to the liquid supply assembly. The peripheral spray assembly is located outside the induction coil and is arranged circumferentially around the induction coil. The input ends of the peripheral spray assembly are connected to both the liquid supply assembly and the recovery assembly. The recovery assembly filters and cools the recovered coolant before supplying it to the peripheral spray assembly for recycling. Thus, through a zoned cooling strategy, the depth and hardness of the hardened layer in the groove area are ensured, while deformation or structural abnormalities in the tooth and pin hole areas due to overheating are avoided. This achieves precise thermal management of critical areas, further improving the overall machining quality and service life of the inner ring.

[0016] Furthermore, the central spray assembly includes a main rod, a first spray assembly, and a second spray assembly. The axis of the main rod is on the same straight line as the axis of the induction coil, and one end of the main rod is connected to the output end of the liquid supply assembly. The first spray assembly and the second spray assembly are arranged at intervals along the axial direction of the main rod, and multiple first spray assemblies and second spray assemblies are provided and arranged circumferentially along the axis of the main rod.

[0017] Furthermore, the spray assembly includes a support rod and a spray element. One end of the support rod is fixedly connected to the outer wall of the main tube, and the other end of the support rod is fixedly connected to the spray element. The spray direction of the spray element is perpendicular to the axis of the support rod, and the spray direction of the spray element is at an acute angle to the tangent of the support rod. Thus, the spray liquid is incident at an inclined angle, forming a spiral cooling flow field on the end face of the billet. This spiral flow field can effectively extend the contact path between the coolant and the end face, improve the heat exchange efficiency, and at the same time avoid local accumulation of coolant on the end face, ensuring cooling uniformity.

[0018] Furthermore, the second spray assembly includes a second support rod and a second spray element. One end of the second support rod is fixedly connected to the outer wall of the main rod tube, and the other end of the second support rod is fixedly connected to the second spray element. The spray direction of the second spray element is perpendicular to the axis of the second support rod, and the spray direction of the second spray element is perpendicular to the tangent of the second support rod. Thus, the spray liquid is vertically injected into the preset hole, forming a vertically downward columnar cooling flow, ensuring that the inner wall of the hole obtains a uniform and concentrated cooling effect.

[0019] Furthermore, the axial length of the first support rod is less than the axial length of the second support rod, and the axial length of the second support rod is less than the radius of the induction coil.

[0020] Furthermore, the peripheral spray assembly includes an upper ring, a lower ring, and a bracket. The upper and lower rings are coaxially arranged with the induction coil, and the induction coil is located between the upper and lower rings. The inner side of the bracket is fixedly connected to the outer side of the upper ring and the outer side of the lower ring. The input end of the upper ring and the input end of the lower ring are respectively connected to the output end of the recycling assembly.

[0021] Furthermore, the inner wall of the upper ring is provided with a plurality of spray elements three, which are evenly spaced along the circumference of the upper ring. The spray direction of the spray elements three is inward and obliquely downward. The inner wall of the lower ring is provided with a plurality of spray elements four, which are evenly spaced along the circumference of the lower ring. The spray direction of the spray elements four is inward and obliquely upward. Thus, the upper ring and the lower ring work together to form opposing inclined jet streams on the upper and lower sides of the induction coil.

[0022] Furthermore, the inner diameter of both the upper and lower ring components is larger than the outer diameter of the induction coil.

[0023] Furthermore, the improved high-frequency quenching device also includes a control system, which includes a time control module, a position detection module, and a logic control module. The time control module is used to set the quenching heating time and cooling sequence. The position detection module monitors the relative position of the induction coil and the billet in real time. The logic control module coordinates and controls the start and stop sequence of the quenching unit and the cooling unit according to the signal fed back by the position detection module, so as to achieve precise linkage between heating and cooling, avoid fluctuations in quenching quality due to timing deviations, and thus improve the automation level and repeatability of the process.

[0024] Furthermore, step S5 specifically includes the following sub-steps: S5.1 The inner ring blank is placed on the positioning unit and moved to the first quenching station through the positioning unit. The quenching unit, cooling unit and control unit quench the top of the inner ring blank. S5.2 Move the inner ring blank to the second quenching station, where the quenching unit, cooling unit and control unit quench the upper half of the sidewall located in the groove area. S5.3 moves the inner ring blank to the third quenching station, where the quenching unit, cooling unit, and control unit quench the groove area. S5.4 Move the inner ring blank to the fourth quenching station, where the quenching unit, cooling unit, and control unit quench the lower half of the sidewall located in the groove area. The S5.5 positioning unit moves the inner ring blank downwards and out of the quenching station, completing the entire quenching process.

[0025] In step S6, blanks with unacceptable hardness are screened out to prevent them from flowing into subsequent processes, thus saving rework and scrap costs caused by unacceptable hardness.

[0026] Furthermore, in step S8, the grinding number of the inner and outer cylindrical grinding is not less than 4 times, preferably 4 to 5 times; in order to gradually reduce the dimensional allowance and eliminate the residual stress of the previous processing, so as to meet the requirements of finished product dimensional tolerance and surface roughness; through the multi-pass grinding process, tool wear is reduced while avoiding thermal damage caused by a large feed rate at one time, ensuring that the surface quality of the inner ring raceway is stable and controllable.

[0027] Furthermore, in step S10, a positioning fixture is used to determine the machining position of the pin hole before precision machining, and each inner ring sample needs to be calibrated; thus, high positional accuracy is ensured by using a positioning fixture and calibrating each piece individually.

[0028] Furthermore, in step S10, after the first piece completes the pin hole finishing, it must be sent to the testing center to conduct a full-size inspection of the pin hole position, diameter, and surface quality using a coordinate measuring machine. Only after passing the inspection can batch processing continue. During batch processing, process sampling inspections are carried out at the prescribed frequency.

[0029] Secondly, the crossed roller bearing manufactured using the aforementioned non-standard thin-walled bearing manufacturing process includes an outer ring, an inner ring, crossed rollers, and a plug; the raceways of the outer ring and the inner ring are arranged at 90° to cross each other, the rollers are embedded in the raceways of the outer ring and the inner ring in a cross shape, and the plug is an elastic retaining ring structure, which is embedded in the annular groove on the end face of the inner ring to restrict the axial movement of the rollers and provide preload; the inner wall of the inner ring is provided with a toothed surface.

[0030] The beneficial effects of this invention are: 1. The manufacturing process of the non-standard thin-walled bearing of the present invention involves pre-drilling a bottom hole with a diameter smaller than the finished diameter of the pin hole at the pin hole position before heat treatment of the inner ring; after heat treatment and all grinding processes are completed, the hole is enlarged and precision machined to the finished size of the pin hole. This effectively avoids the adverse effects of heat treatment deformation on the pin hole accuracy, improves the finished product qualification rate and assembly accuracy, and reduces the subsequent finishing allowance, thereby improving the overall processing efficiency.

[0031] 2. The manufacturing process of the non-standard thin-walled bearing of the present invention uses an improved high-frequency coil device to perform segmented quenching treatment on the inner ring, and achieves magnetic line concentration through the optimization of the magnetic conductor structure, which effectively prevents deformation or abnormal hardness in the pin hole area due to overheating. Attached Figure Description

[0032] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0033] Figure 1 This is a front view of the bearing inner ring.

[0034] Figure 2 yes Figure 1 A cross-sectional view of the inner ring AA of the intermediate bearing.

[0035] Figure 3 This is a flowchart of the manufacturing process for non-standard thin-walled bearings.

[0036] Figure 4 This is a schematic diagram of the structure of the improved high-frequency coil device.

[0037] Figure 5 This is a cooling path diagram for an improved high-frequency coil device.

[0038] Figure 6 This is a schematic diagram of the assembly of the induction coil and the magnetic conductor.

[0039] Figure 7 This is a schematic diagram of a partial cross-section of a magnetic conductor.

[0040] Figure 8 This is a schematic diagram of the central sprinkler system.

[0041] Figure 9 This is a schematic diagram of the external spray system.

[0042] In the diagram: 1. Quenching unit; 11. Induction coil; 12. Magnetic conductor; 2. Cooling unit; 21. Central spray assembly; 211. Main rod; 212. Spray assembly one; 213. Spray assembly two; 22. Peripheral spray assembly; 221. Bracket; 222. Upper ring; 223. Lower ring; 3. Positioning unit; 31. Moving seat; 32. Fixture. Detailed Implementation

[0043] The present invention will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic diagrams, illustrating only the basic structure of the invention, and therefore only show the components relevant to the invention.

[0044] Example 1: like Figure 1 , Figure 2 As shown, the inner ring of the bearing has a thin-walled annular structure. The inner ring includes component one and component two, which are integral components. Component one is... Figure 2 The section marked with fine cross-section lines, component two is Figure 2 The section with medium-coarse cross-section lines is marked; the inner wall of component one is provided with toothed surfaces, and a pin hole and a fixing hole are opened at the end of component one away from component two. The shaft length of the pin hole is greater than the shaft length of component one; the outer wall of component two is provided with a groove, and the longest width of the groove is 4.15mm.

[0045] The relevant parameters of the inner ring finished product are as follows: the tip circle diameter of the inner gear ring is 50.69mm, the root circle diameter of the inner gear ring is 53mm, the shaft length of the inner gear ring is 8mm, the total shaft length of the inner ring is 10mm, the diameter of the circle containing the pin hole center is 42.5mm, the diameter of the pin hole is 2.5mm, and the positional accuracy of the pin hole is 0.02mm.

[0046] like Figure 3 As shown, this embodiment uses a non-standard thin-walled bearing manufacturing process to manufacture a crossed roller bearing, including the following steps: S1: Bearing blank forming: Outer ring blank, inner ring blank and plug blank are manufactured separately through forging process; S2: Normalizing treatment: The outer ring blank, inner ring blank and plug blank are normalized separately to eliminate internal stress, refine grains and improve the stability of subsequent processing; S3: Rough turning: Rough turning is performed on the outer ring blank, inner ring blank, and plug blank to initially shape them and leave room for finishing; among them, the rough turning of the inner ring blank only needs to form a contour; S4: Structural Machining: Machining the inter-hole structural features of the outer ring blank, inner ring blank, and plug blank; wherein, the pin hole position is determined by tooling / CNC, and a drilling device is used to pre-drill a bottom hole at the corresponding position of the pin hole on the inner ring blank. The bottom hole is a blind hole with a diameter of 2mm and a depth of 6.1mm. S5: High-frequency induction hardening: High-frequency induction hardening is performed on the outer ring blank, inner ring blank and plug blank; an improved high-frequency coil device is used to perform segmented hardening on the outer ring blank and inner ring blank, wherein the hardness of the groove surface of the inner ring blank is 61HRC, the hardness of each surface is 45HRC, and the hardness of the pin hole position and the corresponding area of ​​the tooth position is not higher than 30HRC. S6: Hardness Testing: The hardness of each quenched billet was tested using a Vickers hardness tester to ensure that the hardness met the design requirements; multiple samples were taken from the billet surface for testing, and the results are as follows: Outer rings: 62.5, 63, 62.8, 63.5 (outer rings are tempered to 61-65hrc); Inner rings: 44.5, 44.3, 44.5, 44.2; Stopper: 44.3; S7: Finish turning: Finish turning is performed on outer and inner ring blanks with qualified hardness; this reduces the machining allowance and machining time of the grinding machine and improves work efficiency. S8: Grinding process: Perform internal and external cylindrical grinding on the outer ring blank and the inner ring blank. The grinding allowance is controlled at 0.1mm~0.05mm each time. After 4 to 5 times, the qualified size is achieved and the surface roughness Ra≤0.1μm, so that the inner diameter, outer diameter and roughness meet the finished product requirements. S9: Raceway grinding: High-precision CNC raceway grinding machine is used to precisely grind the raceways of the outer ring blank, inner ring blank and plug blank; S10: Pin hole finishing: Perform pin hole finishing on the inner ring that has been quenched and has had its grooves ground. S11: Assembly and Adjustment: Precision assembly of the outer ring, inner ring, plug and roller, and adjustment of preload and rotational accuracy. S12: Final Inspection and Packaging: Perform full-size inspection, vibration and noise testing, and sealing verification on the assembled bearings. Qualified products are then subjected to rust prevention treatment, vacuum packaging, and warehousing.

[0047] in: In step S10, a positioning fixture is used to determine the machining position of the pin hole before precision turning, and each inner ring sample needs to be calibrated. After the pin hole of the first piece is finished, it must be sent to the testing center to use a coordinate measuring machine to conduct a full-size inspection of the pin hole position, diameter and surface quality. Only after the inspection is qualified can batch processing continue. During batch processing, process sampling inspection is carried out at the prescribed frequency.

[0048] Reference Figure 4 The improved high-frequency quenching device includes a machine tool, a quenching unit 1, a cooling unit 2, and a positioning unit 3. The machine tool includes a water tank and a side wall. The side wall is located on one side of the water tank. The quenching unit 1 is detachably mounted on the side wall, and the cooling unit 2 is located at one end of the quenching unit 1. The positioning unit 3 is located inside the water tank and below the quenching unit 1. The quenching unit 1 is used for segmented heating of the billet. The cooling unit 2 uses water cooling to rapidly cool the heated area, and the positioning unit 3 is used to gradually move the billet to the quenching station.

[0049] Reference Figure 4 , Figure 6 The quenching unit 1 includes a frame, an induction coil 11, and a magnetic conductor 12. One end of the frame is snapped into the side wall. The positive and negative poles of the induction coil 11 are fixedly connected to the bottom of the frame, and the positive and negative ends of the induction coil 11 are connected to a high-frequency power supply. The induction coil 11 is located below the frame and has a rectangular cross-section. The axial thickness of the induction coil 11 is less than the axial width of the channel. In this embodiment, the axial thickness of the induction coil 11 is 2 mm. The magnetic conductor 12 partially covers the outside of the induction coil 11 to maintain the shape of the induction coil 11 and enhance its magnetic field concentration.

[0050] Refer to Figure 6 , Figure 7The magnetic conductor 12 has a U-shaped vertical cross-section with the U-shaped opening facing outwards. The induction coil 11 is embedded in the U-shaped groove of the magnetic conductor 12, and the thickness of the upper horizontal arm of the magnetic conductor 12 is greater than the thickness of the lower horizontal arm. The magnetic conductor 12 has a C-shaped horizontal cross-section, and the positive and negative poles of the induction coil 11 are located in the C-shaped opening of the magnetic conductor 12.

[0051] Reference Figure 7 The upper and lower surfaces of the magnetic conductor 12 are both conical structures. The taper directions of the upper and lower surfaces of the magnetic conductor 12 are opposite, and the upper and lower surfaces form an angle α, which ranges from 15° to 20°.

[0052] Reference Figure 4 , Figure 5 The cooling unit 2 includes a central spray assembly 21, a peripheral spray assembly 22, a control assembly, a liquid supply assembly, and a recovery assembly. The control assembly is mounted on the frame. The central spray assembly 21 is located inside the induction coil 11. The control assembly controls the central spray assembly 21 to move along the axial direction of the induction coil 11. The input end of the central spray assembly 21 is connected to the liquid supply assembly. The peripheral spray assembly 22 is located outside the induction coil 11 and is arranged circumferentially around the induction coil 11. The input end of the peripheral spray assembly 22 is connected to the recovery assembly. The recovery assembly filters and cools the recovered coolant before supplying it to the peripheral spray assembly 22 for recycling. The recovery assembly and the liquid supply assembly are existing technologies and will not be described in detail here.

[0053] Reference Figure 5 , Figure 9 The central spray assembly 21 includes a main rod 211, a first spray assembly 212, and a second spray assembly 213. The axis of the main rod 211 is on the same straight line as the axis of the induction coil 11, and one end of the main rod 211 is connected to the output end of the liquid supply assembly. The first spray assembly 212 and the second spray assembly 213 are arranged at intervals along the axial direction of the main rod 211, with multiple units of each type, arranged circumferentially along the axis of the main rod 211. The end of the frame away from the side wall is U-shaped, with the main rod 211 located inside the U-shaped opening and fitted with a clearance. The control assembly is existing technology, using a servo motor to drive a lead screw to move a control board. The end of the control board away from the lead screw is fixedly connected to the main rod 211, thereby driving the central spray assembly 21 to move axially along the induction coil 11.

[0054] Reference Figure 8 The spray assembly 212 includes a support rod and a spray element. One end of the support rod is fixedly connected to the outer wall of the main rod 211 pipe, and the other end of the support rod is fixedly connected to the spray element. The spraying direction of the spray element is perpendicular to the axis of the support rod, and the spraying direction of the spray element is at an acute angle to the tangent of the support rod.

[0055] The second spray assembly 213 includes a second support rod and a second spray element. One end of the second support rod is fixedly connected to the outer wall of the main rod 211 pipe, and the other end of the second support rod is fixedly connected to the second spray element. The spray direction of the second spray element is perpendicular to the axis of the second support rod, and the spray direction of the second spray element is perpendicular to the tangent of the second support rod. The axial length of the first support rod is less than the axial length of the second support rod, and the axial length of the second support rod is less than the radius of the induction coil 11.

[0056] Reference Figure 4 , Figure 5 and Figure 9 The peripheral spray assembly 22 includes an upper ring 222, a lower ring 223, and a bracket 221. The upper ring 222 and the lower ring 223 are both coaxially arranged with the induction coil 11. The induction coil 11 is located between the upper ring 222 and the lower ring 223. The inner side of the bracket 221 is fixedly connected to the outer side of the upper ring 222 and the outer side of the lower ring 223. The input end of the upper ring 222 and the input end of the lower ring 223 are respectively connected to the output end of the recycling assembly. The inner diameter of the upper ring 222 and the inner diameter of the lower ring 223 are both larger than the outer diameter of the induction coil 11.

[0057] The inner wall of the upper ring 222 is provided with a plurality of spray elements three, which are evenly spaced along the circumference of the upper ring 222. The spraying direction of the spray elements three is inward and obliquely downward. The inner wall of the lower ring 223 is provided with a plurality of spray elements four, which are evenly spaced along the circumference of the lower ring 223. The spraying direction of the spray elements four is inward and obliquely upward.

[0058] Reference Figure 4 The positioning unit 3 includes a lifting device, a movable seat 31, and a fixed fixture 32. The lifting device is existing technology and includes a movable seat. The movable seat is fixedly connected to the movable seat 31. The fixed fixture 32 is detachably installed on the movable seat 31. The inner ring blank is placed on the fixed fixture 32 and is coaxially arranged with the fixed fixture 32. Component 1 is located above component 2. The lifting device adjusts the height of the movable seat 31, thereby adjusting the distance between the inner ring blank and the induction coil 11.

[0059] The fixed fixture 32 has a flow channel, one end of which extends through the top of the fixed fixture 32. The movable seat 31 also has a flow channel, one end of which is connected to the flow channel in the fixed fixture 32, and the other end is connected to the input end of the recycling component. The recycling component has two output ends, which are connected to the input end of the upper ring 222 and the input end of the lower ring 223, respectively.

[0060] The improved high-frequency quenching device also includes a control system, which includes a time control module, a position detection module, and a logic control module. The time control module is used to set the quenching heating time and cooling sequence. The position detection module monitors the relative position of the induction coil 11 and the billet in real time. The logic control module coordinates and controls the start and stop sequence of the quenching unit 1 and the cooling unit 2 based on the signal fed back by the position detection module, so as to achieve precise linkage between heating and cooling, avoid fluctuations in quenching quality due to timing deviations, and thus improve the automation level and repeatability of the process.

[0061] The working process of the above-mentioned improved high-frequency quenching device is as follows: The inner ring blank is placed on the positioning unit 3, and the control system moves it to the first quenching station through the positioning unit 3. Component 1 is located below the induction coil 11. The control system starts the quenching unit 1 and the cooling unit 2. The induction coil 11 heats the top of the inner ring blank, while the spray assembly 1 212 sprays and cools the inner tooth surface of component 1. The spray assembly 213 sprays and cools the fixing hole and bottom hole of component 1. The flow channel in the positioning unit 3 recovers the coolant to the recovery assembly. After processing, it is supplied to the upper ring 222 and the lower ring 223 respectively. The upper ring 222 cools the outer top of component 1, and the lower ring 223 cools the connection between component 1 and component 2, thus completing the quenching process of the first quenching station.

[0062] Subsequently, according to the timing sequence set by the time control module, the control system controls the positioning unit 3 to move the inner ring blank upwards, and simultaneously controls the adjustment component to move the main rod 211 upwards, so that the main rod 211 and the fixed fixture 32 always maintain a constant relative position. Based on the signal feedback from the position detection module, the control system confirms that the inner ring blank has reached the second quenching station, and then the positioning unit 3 pauses, immediately increasing the power of the induction coil 11 to concentrate heating on the upper half of the groove area's sidewall; the first spray assembly 212 provides enhanced cooling to the inner tooth surface, the second spray assembly 213 continuously cools the fixing hole and bottom hole, the upper ring 222 cools the outer side of component one, and the lower ring 223 cools the groove of component two. When the specified timing sequence is reached, the quenching process of the second quenching station is completed.

[0063] Subsequently, the control system controls the positioning unit 3 to move the inner ring blank upwards, and simultaneously controls the regulating component to move the main rod 211 upwards; based on the signal fed back by the position detection module, the control system confirms that the inner ring blank has reached the third quenching station, the positioning unit 3 pauses, and then increases the power of the induction coil 11 again to concentrate the heating of the channel area; at this time, the control system controls the liquid supply component to reduce the flow rate of the central spray component 21 and increase the flow rate of the peripheral spray component 22; the upper ring 222 cools the upper half of the side wall of component two, and the lower ring 223 cools the lower half of the side wall of component two. When the specified sequence is reached, the quenching treatment of the third quenching station is completed.

[0064] Subsequently, the control system controls the positioning unit 3 to move the inner ring blank upwards, while simultaneously controlling the regulating component to move the main rod 211 upwards. Based on feedback from the position detection module, the control system confirms that the inner ring blank has reached the fourth quenching station. The positioning unit 3 then pauses and reduces the power of the induction coil 11 to supplement the heating of the lower half of the sidewall of the channel area. At the same time, the control system controls the liquid supply component to further reduce the flow rate of the central spray component 21 and increase the flow rate of the peripheral spray component 22. The upper ring 222 cools the channel of component two, and the lower ring 223 cools the lower end face of component two. When the specified sequence is reached, the quenching process of the fourth quenching station is completed.

[0065] Finally, the control system controls the positioning unit 3 to move the inner ring blank downwards, returning it to its initial position, while simultaneously shutting off the induction coil 11 and all spray components.

[0066] Compared to samples manufactured using conventional processes:

[0067] As can be seen from the table above, compared with conventional manufacturing processes, this process significantly reduces the positional error rate and scrap rate by combining segmented quenching and precise cooling, while greatly improving the hardness compliance.

[0068] Example 2: This example is a variation, and its difference from Example 1 is as follows: In step S5, a comparative experiment was conducted using a high-frequency quenching device with only a thin coil and no magnetic conductor, a high-frequency quenching device with a flat magnetic conductor, and the improved high-frequency quenching device used in Example 1. The experimental results are as follows:

[0069] As can be seen from the table, the improved high-frequency quenching device (i.e., the device used in Example 1) employs an angled magnetic conductor structure, which effectively guides magnetic lines of force to concentrate in the channel area, achieving precise heating and thus significantly improving quenching quality and yield. In contrast, the scheme without a magnetic conductor cannot complete quenching due to coil deformation, while the scheme with a straight magnetic conductor suffers from poor heating uniformity due to insufficient magnetic focusing effect.

[0070] Example 3: This example is a variation, and its difference from Example 1 is as follows: In step S4, the diameters of the roughing bore were 2.3 mm, 2.2 mm, 1.8 mm, and 1.7 mm, respectively, and compared with the 2 mm bore in Example 1. The experimental results are as follows:

[0071] As can be seen from the table, when the bottom hole diameter is 2mm, the position accuracy is optimal and the tool wear is controllable. When the diameter is less than 2mm, the position accuracy is similar but the tool wear increases significantly. When the diameter is greater than 2mm, the position accuracy deteriorates significantly.

[0072] Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A manufacturing process for a non-standard thin-walled bearing, characterized in that, Includes the following steps: S1. Blank forming: Obtain outer ring blank, inner ring blank and plug blank through forging process, and leave machining allowance for subsequent processes; S2. Normalizing treatment: The outer ring billet, inner ring billet and plug billet are normalized separately; S3. Rough turning: Rough turning is performed on the outer ring blank, inner ring blank and plug blank to initially shape them and leave room for finishing. S4: Structural machining: Machining the inter-hole structural features of the outer ring blank, inner ring blank, and plug blank; S5: Quenching process: High-frequency induction quenching is performed on the outer ring blank, inner ring blank and plug blank; S6: Hardness test: Perform hardness test on each billet after quenching to ensure that the hardness meets the design requirements; S7: Finish turning: Finish turning is performed on the outer ring blank and inner ring blank with qualified hardness. S8: Grinding process: Internal and external cylindrical grinding of outer ring blanks and inner ring blanks; S9: Groove grinding: Groove grinding of outer ring blanks, inner ring blanks and plug blanks; S10: Pin hole finishing: finish machining of the pin holes on the inner ring; S11: Assembly and Adjustment: Precision assembly of the outer ring, inner ring, plug and roller, and adjustment of preload and rotational accuracy. S12: Final Inspection and Packaging: Perform full-size inspection, vibration and noise testing, and sealing verification on the assembled bearings. Qualified products are then subjected to rust prevention treatment, vacuum packaging, and warehousing.

2. The manufacturing process of the non-standard thin-walled bearing according to claim 1, characterized in that: In step S3, the approximate outline of the outer groove of the inner ring blank is rough-machined, and the approximate outline of the inner tooth surface is rough-machined.

3. The manufacturing process of the non-standard thin-walled bearing according to claim 1, characterized in that: In step S4, a pilot hole is pre-drilled at the position corresponding to the pin hole of the inner ring blank; the diameter of the pilot hole is 0.3 to 0.7 mm smaller than the diameter of the final pin hole.

4. The manufacturing process of the non-standard thin-walled bearing according to claim 1, characterized in that: In step S5, an improved high-frequency quenching device is used to perform high-frequency induction quenching on the inner ring. The improved high-frequency quenching device can precisely prevent the pin hole position and tooth position area from being hardened during the quenching process.

5. The manufacturing process of the non-standard thin-walled bearing according to claim 4, characterized in that: The improved high-frequency quenching device includes: Quenching unit (1), the quenching unit (1) is used to heat the billet in sections, the quenching unit (1) includes an induction coil (11) and a magnetic conductor (12), the induction coil (11) is a ring structure, the magnetic conductor (12) is partially covered on the outside of the induction coil (11), and the axial thickness of the induction coil (11) is less than the axial width of the bearing channel; The cooling unit (2) includes a central spray assembly (21), a peripheral spray assembly (22), a liquid supply assembly, and a recovery assembly. The central spray assembly (21) is located inside the induction coil (11) and is movably arranged along the axial direction of the induction coil (11). The input end of the central spray assembly (21) is connected to the liquid supply assembly. The peripheral spray assembly (22) is located outside the induction coil (11) and is arranged in the circumferential direction of the induction coil (11). The input end of the peripheral spray assembly (22) is connected to the liquid supply assembly and the recovery assembly, respectively. Positioning unit (3), located below induction coil (11), is used to carry and position the bearing blank to be quenched and move it step by step to the quenching station.

6. The manufacturing process of the non-standard thin-walled bearing according to claim 5, characterized in that: The horizontal cross-section of the magnetic conductor (12) is C-shaped, the vertical cross-section of the magnetic conductor (12) is U-shaped, the U-shaped opening of the magnetic conductor (12) faces outward, the induction coil (11) is embedded in the U-shaped groove of the magnetic conductor (12), and the thickness of the upper horizontal arm of the magnetic conductor (12) is greater than the thickness of the lower horizontal arm. The upper and lower surfaces of the magnetic conductor (12) are both conical structures. The upper and lower surfaces of the magnetic conductor (12) have opposite taper directions and form an angle α. The value of the angle α ranges from 15° to 20°.

7. The manufacturing process of the non-standard thin-walled bearing according to claim 5, characterized in that: The central spray assembly (21) includes a main rod (211), a first spray assembly (212), and a second spray assembly (213). The main rod (211) can move up and down along the axis of the induction coil (11), and one end of the main rod (211) is connected to the output end of the liquid supply assembly. The first spray assembly (212) and the second spray assembly (213) are arranged at intervals along the axial direction of the main rod (211). There are multiple first spray assemblies (212) and second spray assemblies (213), and they are arranged circumferentially along the axis of the main rod (211). The peripheral spray assembly (22) includes an upper ring (222), a lower ring (223), and a bracket (221). The upper ring (222) and the lower ring (223) are both coaxially arranged with the induction coil (11). The induction coil (11) is located between the upper ring (222) and the lower ring (223). The inner side of the bracket (221) is fixedly connected to the outer side of the upper ring (222) and the outer side of the lower ring (223). The input end of the upper ring (222) and the input end of the lower ring (223) are respectively connected to the output end of the recycling assembly.

8. The manufacturing process of the non-standard thin-walled bearing according to claim 5, characterized in that: Step S5 further includes the following sub-steps: S5.1 Place the inner ring blank on the positioning unit (3) and move it to the first quenching station through the positioning unit (3). The quenching unit (1), cooling unit (2) and control unit work together to quench the top of the inner ring blank. S5.

2. Move the inner ring blank to the second quenching station. The quenching unit (1), cooling unit (2) and control unit quench the upper half of the sidewall located in the groove area. S5.

3. Move the inner ring blank to the third quenching station, and the quenching unit (1), cooling unit (2) and control unit quench the channel area. S5.

4. Move the inner ring blank to the fourth quenching station. The quenching unit (1), cooling unit (2) and control unit quench the lower half of the sidewall located in the groove area. S5.5, Positioning unit (3) moves the inner ring blank down and out of the quenching station to complete the entire quenching process.

9. The manufacturing process of the non-standard thin-walled bearing according to claim 1, characterized in that: In step S6, a Vickers hardness tester is used to perform deep hardness testing on each blank after quenching to confirm that the surface and subsurface hardness of each component is 40HRC to 45HRC; and the hardness of the pin hole position and the corresponding area of ​​the tooth position is less than or equal to 30HRC, and the hardness of the groove surface is 61HRC to 65HRC.

10. The manufacturing process of the non-standard thin-walled bearing according to claim 1, characterized in that: In step S8, the grinding of the inner and outer cylindrical grinding processes is no less than 4 times.

11. The manufacturing process of the non-standard thin-walled bearing according to claim 1, characterized in that: In step S10, the machining position of the pin hole is determined before precision turning by using a positioning fixture; after the pin hole is precision machined on the first piece, it is sent to the inspection center to conduct a full-size inspection of the pin hole position, diameter and surface quality using a coordinate measuring machine. Only after the inspection is qualified can batch processing continue; during batch processing, process sampling inspection is carried out at the prescribed frequency.

12. A crossed roller bearing manufactured according to the preparation process of any one of claims 1-11, characterized in that: Includes outer ring, inner ring, cross-arranged rollers and plugs; The raceways of the outer ring and the inner ring are arranged at a 90° angle. The rollers are embedded in the raceways of the outer and inner rings in a cross shape. The plug is an elastic retaining ring structure and is embedded in the annular groove on the end face of the inner ring. The inner ring has a toothed surface on its inner wall; the surface hardness of the inner ring is 40HRC~45HRC; the end face of the inner ring has a pin hole with a pin hole position tolerance of 0.02-0.08mm.

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