A high-nitrogen stainless steel tapered roller bearing outer ring induction quenching device and method

Abstract

The application relates to a high-nitrogen stainless steel conical roller bearing outer ring induction quenching device and method, and belongs to the technical field of heat treatment. The device comprises a rack and an inductor arranged at the lower end of the rack. The inductor is in the shape of a conical ring. The inductor is arranged in a conical roller bearing outer ring and used for quenching a raceway in the conical roller bearing outer ring. The outer surface of the inductor is provided with a conical ring-shaped groove facing the raceway. The taper of the conical ring-shaped groove is the same as that of the raceway. A liquid spraying device for spraying quenching liquid is arranged at the lower end of the inductor. The liquid spraying device can spray quenching liquid to the raceway. The application can solve the problems of the uneven depth of the hardened layer of the raceway of the conical roller bearing outer ring and the overheating of the metallographic structure in the middle of the raceway of the conical roller bearing outer ring caused by the existing induction quenching device.

Description

Technical Field

[0001] This invention relates to the field of heat treatment technology, and in particular to an induction hardening apparatus and method for the outer ring of a high-nitrogen stainless steel tapered roller bearing. Background Technology

[0002] Induction hardening utilizes the electromagnetic induction effect, using a heating inductor to generate an induced current on the workpiece surface. The surface layer is rapidly heated by the thermal effect of this current, and then hardened by a cooling medium. For high-nitrogen stainless steel tapered bearing outer rings, induction hardening should achieve a uniform and sufficiently deep hardened layer on the raceway. The surface hardness of this hardened layer should reach 58-62 HRC to meet the bearing design requirements, and the hardened layer should not exhibit abnormal structures such as overheating or underheating. Therefore, for high-nitrogen stainless steel tapered bearing outer rings with irregular structures, suitable induction hardening methods and compatible inductors need to be developed to meet these technical requirements.

[0003] Existing induction hardening equipment such as Figure 8 As shown, the inductor extends into the outer ring of the bearing to perform induction hardening on the raceway inside the outer ring. However, after use, it was found that after induction hardening, as... Figure 9 and Figure 10 As shown, this not only easily leads to uneven hardened layer depths in the raceway of the outer ring of tapered roller bearings, but also... Figure 11 As shown, this can easily lead to an overheated state in the intermediate metallographic structure of the outer ring raceway of the tapered roller bearing, making it difficult to meet the bearing design requirements. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide an induction hardening device and method for the outer ring of a high-nitrogen stainless steel tapered roller bearing, so as to solve the problems of inconsistent morphology of the hardened layer in the raceway of the outer ring of the tapered roller bearing and overheating of the metallographic structure in the middle of the raceway of the outer ring of the tapered roller bearing caused by the existing induction hardening device.

[0005] The technical solution adopted by the present invention to solve the above-mentioned technical problems is: an induction hardening device for the outer ring of a high-nitrogen stainless steel tapered roller bearing, comprising a frame and an inductor disposed at the lower end of the frame. The inductor is in the shape of a conical ring and is placed inside the outer ring of the tapered roller bearing for quenching the raceway inside the outer ring of the tapered roller bearing. The outer surface of the inductor is provided with a conical annular groove facing the raceway, and the taper of the conical annular groove is the same as the taper of the raceway. The lower end of the inductor is provided with a spraying device for spraying quenching liquid, which can spray quenching liquid onto the raceway.

[0006] Preferably, the cross-sectional shape of the conical annular groove is an isosceles trapezoid.

[0007] Preferably, the spraying device includes a spraying ring with a rectangular cross-sectional shape and a notched annular shape. Multiple spraying holes are provided on the outer circumference of the spraying ring. The spraying ring is connected to an inlet pipe for receiving external quenching liquid.

[0008] Preferably, the frame includes a fixed insulating plate, the fixed insulating plate and the spray ring are connected by a connecting assembly, the sensor is sleeved on the outside of the connecting assembly, and the sensor is connected to the connecting assembly by a positioning assembly.

[0009] Preferably, the connecting assembly includes multiple screws disposed on the spray ring, with two locking nuts threaded on the screws, and the screws pass through the fixed insulating plate and are clamped and fixed by the two locking nuts.

[0010] Preferably, the inner ring of the sensor is provided with multiple connecting plates. The upper end of the connecting plates is arranged in layers from bottom to top with an upper insulating block and a clamping nut. A lower insulating block is provided between the connecting plates and the spray ring. The screw passes through the lower insulating block, the connecting plates, the upper insulating block and the clamping nut in sequence. The clamping nut is threadedly engaged with the screw. The connecting plate is provided with a positioning hole for the screw to pass through. The lower end of the upper insulating block is provided with an annular protrusion that extends into the positioning hole and is inserted into the positioning hole.

[0011] Preferably, the sensor further includes a sensor power board connected to the sensor, the sensor power board is disposed at the lower end of the fixed insulating plate, and magnetic conductors are respectively provided at the upper and lower ends of the sensor.

[0012] This application also provides a method for induction hardening of the outer ring of a high-nitrogen stainless steel tapered roller bearing, using the aforementioned induction hardening apparatus for the outer ring of a high-nitrogen stainless steel tapered roller bearing, comprising the following steps:

[0013] S1. Install a lifting sleeve on the rotary table of the quenching machine tool. The lifting sleeve has a stepped groove. Place the outer ring of the tapered roller bearing on the stepped groove.

[0014] S2. Install the frame at the lower end of the lifting worktable of the quenching machine tool. The lifting worktable drives the frame to descend, which in turn moves the sensor to the outer ring of the tapered roller bearing and aligns the sensor with the raceway. The sensor then performs induction quenching on the raceway.

[0015] S3. After quenching, the lifting worktable drives the frame to rise. When the spraying device moves to the position facing the roller track, it stops rising and sprays quenching liquid onto the roller track to cool it.

[0016] S4. After cooling is complete, the lifting worktable drives the frame to rise, so that the liquid spraying device is completely separated from the outer ring of the tapered roller bearing, and the raceway quenching heat treatment is completed.

[0017] Furthermore, in step S2, the frequency of induction hardening is 12-16 kHz, the power is 150-152 kW, the heating time is 4-10 s, and the rotation speed of the rotary table is 160 r / min-180 r / min; in step S3, the cooling time is 28-30 s.

[0018] Furthermore, in step S1, the cross-sectional shape of the lifting sleeve is concave, and the sensor can extend into the lifting sleeve. The outer ring of the tapered roller bearing has an assembly mating surface, and the connection between the assembly mating surface and the raceway is the boundary area. In step S2, when the sensor corresponds to the raceway, the lower part of the sensor protrudes out of the outer ring of the tapered roller bearing, and the upper part of the sensor is higher than the boundary area.

[0019] The beneficial effects of this application are as follows: 1. The sensor of this application has a conical annular groove on the inclined surface area of ​​the product raceway, which effectively improves the problem of overheating in the middle of the product raceway; and when the sensor corresponds to the raceway, the lower part of the sensor protrudes from the outer ring of the tapered roller bearing, and the upper part of the sensor is higher than the junction area, so that the sensor covers the large end face of the raceway and the junction area between the raceway and the assembly mating surface. By utilizing the two sharp corner effects of the large end face and the junction area between the raceway and the assembly mating surface, the heating intensity at both ends of the raceway is increased, the problem of insufficient heating is improved, and finally the consistency of the structure and hardness of the hardened layer area on both sides and in the middle of the raceway is achieved.

[0020] 2. This application ensures the stability and consistency of the quenching quality of the bearing outer ring by setting process parameters such as heating frequency, heating power, heating time, rotation speed and cooling time.

[0021] 3. This application ensures the stable connection, fixation, and electrical insulation of the sensor, spray ring, and fixed insulating plate by setting up an upper insulating block, a clamping nut, a lower insulating block, a screw, and a locking nut. The structure is simple and the installation and adjustment are convenient. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the structure of the present invention.

[0023] Figure 2 This is a top view of the present invention.

[0024] Figure 3 This is a schematic diagram of the processing of the present invention.

[0025] Figure 4 This is a schematic diagram of the hardened layer morphology of the outer ring raceway of the tapered roller bearing of the present invention after induction hardening.

[0026] Figure 5 The metallographic structure of the raceway hardened layer after induction hardening of the outer ring of the tapered roller bearing of the present invention is described.

[0027] Figure 6 This is a schematic diagram of the three parts of the raceway selected in this invention.

[0028] Figure 7 This is a schematic diagram showing the hardness gradient of three parts of the raceway after induction hardening of the outer ring of the tapered roller bearing of the present invention.

[0029] Figure 8 This is a schematic diagram of induction hardening of the outer ring of an existing tapered roller bearing.

[0030] Figure 9 This is a schematic diagram showing the varying depths of the hardened layer on the outer ring raceway of an existing induction-hardened tapered roller bearing.

[0031] Figure 10 The image shows actual photographs of tapered roller bearings with varying depths of hardened layers on the outer ring raceway after induction hardening.

[0032] Figure 11 This is a schematic diagram of the overheated metallographic structure in the middle of the raceway of the outer ring of an existing induction hardened tapered roller bearing.

[0033] Illustration markings: 1. Outer ring of tapered roller bearing; 11. Raceway; 12. Assembly mating surface; 13. Boundary area; 2. Sensor; 21. Conical annular groove; 22. Sensor energizing plate; 23. Magnetic conductor; 24. Connecting plate; 3. Spray ring; 31. Spray hole; 32. Inlet pipe; 4. Fixed insulating plate; 5. Screw; 51. Locking nut; 52. Compression nut; 6. Upper insulating block; 61. Annular protrusion; 7. Lower insulating block; 8. Lifting sleeve; 81. Stepped groove; A. Raceway near the large end face; B. Raceway middle position; C. Raceway near the small end face. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that, in the description of this invention, unless otherwise stated, "a plurality of" means two or more; the terms "upper," "lower," "left," "right," "inner," "outer," "front end," "rear end," "head," "tail," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0035] Please see Figure 1-3This invention provides an induction hardening device for the outer ring of a high-nitrogen stainless steel tapered roller bearing, comprising a frame and an inductor 2 disposed at the lower end of the frame. The inductor 2 is in the shape of a conical ring and is placed inside the outer ring 1 of the tapered roller bearing for hardening the raceway 11 inside the outer ring 1. The taper of the inductor 2 is the same as the taper of the raceway 11. The outer surface of the inductor 2 is provided with a conical annular groove 21 facing the raceway 11, and the taper of the conical annular groove 21 is the same as the taper of the raceway 11. The lower end of the inductor 2 is provided with a spraying device for spraying quenching liquid, which can spray quenching liquid onto the raceway 11 for cooling.

[0036] The conical annular groove 21 has an isosceles trapezoidal cross-section. The spraying device includes a spraying ring 3 with a rectangular cross-section. Multiple spraying holes 31 are provided on the outer circumference of the spraying ring 3. The spraying ring 3 is connected to an inlet pipe 32, which is used to connect to an external quenching liquid source. Multiple inlet pipes 32 are evenly distributed along the circumference of the spraying ring 3 on its inner side. The multiple spraying holes 31 are evenly distributed along the outer circumference of the spraying ring 3, ensuring uniform cooling. The spraying ring 3 is a notched annular shape and is made of copper. If the spray ring 3 is a complete circular ring, when the complete circular ring is placed in the magnetic field of the sensor 2, the magnetic field will preferentially act on the metal with lower resistance, thereby generating an induced current, i.e., eddy current, inside the complete circular ring. Since copper has low resistance, the eddy current is large, and the complete circular ring will heat up significantly, affecting the cooling effect. Furthermore, at this time, the complete circular ring forms a loop, which will weaken the magnetic field acting on one side of the large end face of the raceway 11, affecting the heating effect of the sensor 2 on the raceway 11.

[0037] Specifically, the frame includes a fixed insulating plate 4, which is connected to the spray ring 3 via a connecting assembly. A sensor 2 is sleeved on the outside of the connecting assembly and is connected to the connecting assembly via a positioning assembly. The connecting assembly includes multiple screws 5 mounted on the spray ring 3. Two locking nuts 51 are threaded onto each screw 5. The screws 5 pass through the fixed insulating plate 4 and are clamped and fixed by the two locking nuts 51, thereby connecting and fixing the spray ring 3 to the fixed insulating plate 4 together. During clamping, the two locking nuts 51 are located on the upper and lower sides of the fixed insulating plate 4, respectively.

[0038] Furthermore, the inner ring of the sensor 2 is provided with multiple connecting plates 24. From bottom to top, upper insulating blocks 6 and clamping nuts 52 are stacked on the upper end of the connecting plates 24. A lower insulating block 7 is provided between the connecting plates 24 and the spray ring 3. The screw 5 passes through the lower insulating block 7, connecting plates 24, upper insulating blocks 6, and clamping nuts 52 in sequence, with the clamping nuts 52 threadedly engaged with the screw 5. The connecting plates 24 have positioning holes for the screw 5 to pass through. The lower end of the upper insulating block 6 has an annular protrusion 61 that extends into and engages with the positioning hole. By tightening the clamping nuts 52, the connecting plates 24 can be pressed between the upper insulating blocks 6 and the lower insulating blocks 7, thereby achieving the connection and fixation between the sensor 2 and the spray ring 3. The connecting plates 24 are made of copper and are welded to the sensor 2. By setting the upper insulating blocks 6 and the lower insulating blocks 7, the high-frequency current of the sensor 2 is prevented from being conducted to other components through the connecting assembly.

[0039] The sensor 2 also includes a sensor power board 22 connected to the sensor 2. The sensor power board 22 is located at the lower end of the fixed insulating plate 4, and magnetic conductors 23 are respectively provided at the upper and lower ends of the sensor 2. The sensor power board 22 is connected to an external power source. The sensor power board 22 is provided with a cooling pipe that passes through the sensor power board 22 and is used to cool the sensor 2. One end of the cooling pipe is a water inlet, and the other end is a water outlet. The water inlet is connected to a water source.

[0040] This application embodiment also provides a method for induction hardening of the outer ring of a high-nitrogen stainless steel tapered roller bearing, using the above-mentioned induction hardening device for the outer ring of a high-nitrogen stainless steel tapered roller bearing, including the following steps:

[0041] S1. A lifting sleeve 8 is installed on the rotary table of the quenching machine. The lifting sleeve 8 has a stepped groove 81. The outer ring 1 of the tapered roller bearing is placed on the stepped groove 81. The cross-sectional shape of the lifting sleeve 8 is concave, allowing the sensor 2 to extend into the lifting sleeve 8. The outer ring 1 of the tapered roller bearing is made of high-nitrogen stainless steel, grade 40Cr15Mo2VN.

[0042] S2. The frame is installed at the lower end of the lifting worktable of the quenching machine. The lifting worktable lowers the frame, moving the inductor 2 into the outer ring 1 of the tapered roller bearing, aligning the inductor 2 with the raceway 11. The inductor 2 performs induction quenching on the raceway 11. The induction quenching frequency is 12-16 kHz, the power is 150-152 kW, the heating time is 4-10 seconds, and the rotation speed of the rotary worktable is 160-180 r / min. Preferably, the induction quenching frequency is 14 kHz.

[0043] S3. After quenching, the lifting worktable raises the frame. When the spraying device moves to a position facing the raceway 11, it stops rising. The spraying device sprays quenching liquid onto the raceway 11 for cooling, with a cooling time of 28-30 seconds. The quenching liquid enters the spraying ring 3 through the inlet pipe 32 and is then evenly sprayed onto the surface of the raceway 11 from the spraying hole 31 for rapid cooling. The outer ring 1 of the tapered roller bearing has an assembly mating surface 12. The junction between the assembly mating surface 12 and the raceway 11 is the boundary area 13. In step S2, when the sensor 2 corresponds to the raceway 11, the lower part of the sensor 2 protrudes from the outer ring 1 of the tapered roller bearing, and the upper part of the sensor 2 is higher than the boundary area 13.

[0044] S4. After cooling is complete, the lifting platform raises the frame, causing the sensor 2 and the liquid spray ring 3 to completely detach from the outer ring 1 of the tapered roller bearing, completing the quenching heat treatment of the raceway 11. Then, the quenched outer ring 1 of the tapered roller bearing can be removed.

[0045] The surface of the raceway 11 of the outer ring 1 of the quenched tapered roller bearing is inspected, such as... Figure 4 As shown, the morphology of raceway 11 reveals a uniformly distributed hardened layer without variations in depth. Figure 5 As shown, the hardened layer microstructure of raceway 11 consists of uniform and fine martensite and carbides. Figure 6 As shown, hardness tests were performed on three locations on raceway 11: location A near the large end face, location B in the middle of the raceway, and location C near the small end face. The surface hardnesses of locations A, B, and C were 60.3 HRC, 60.1 HRC, and 61.1 HRC, respectively, with hardened layer depths of 2.7 mm, 2.6 mm, and 2.6 mm. All three locations met the requirement of 58-62 HRC, exhibiting minimal hardness fluctuations and uniform hardened layer depth. The hardness gradient of the three locations on raceway 11 is shown below. Figure 7 As shown, the hardness of the three parts changes gradually with depth, and the transition layer is uniform.

[0046] It should be noted that the above embodiments are only used to illustrate the present invention, but the present invention is not limited to the above embodiments. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A method for induction hardening of the outer ring of a high-nitrogen stainless steel tapered roller bearing, comprising an induction hardening device for the outer ring of a high-nitrogen stainless steel tapered roller bearing, the device including a frame and an inductor (2) disposed at the lower end of the frame, the inductor (2) being conical in shape, the inductor (2) being inserted into the outer ring (1) of the tapered roller bearing for hardening the raceway (11) within the outer ring (1), characterized in that, The outer surface of the sensor (2) is provided with a conical annular groove (21) facing the raceway (11). The taper of the conical annular groove (21) is the same as the taper of the raceway (11). The lower end of the sensor (2) is provided with a spraying device for spraying quenching liquid. The spraying device can spray quenching liquid onto the raceway (11). The cross-sectional shape of the conical annular groove (21) is an isosceles trapezoid. The spraying device includes a spraying ring (3). The cross-sectional shape of the spraying ring (3) is rectangular. The spraying ring (3) is a notched annular shape. Multiple spraying holes (31) are provided on the outer circumference of the spraying ring (3). The spraying ring (3) is connected to the liquid inlet pipe (32). The liquid inlet pipe (32) is used to connect to the external quenching liquid. The quenching method includes the following steps: S1. Install a lifting sleeve (8) on the rotary table of the quenching machine tool. The lifting sleeve (8) has a stepped groove (81). Place the outer ring (1) of the tapered roller bearing on the stepped groove (81). S2. Install the frame at the lower end of the lifting worktable of the quenching machine tool. The lifting worktable drives the frame to descend, which in turn moves the sensor (2) to the outer ring (1) of the tapered roller bearing and makes the sensor (2) correspond to the raceway (11). The sensor (2) performs induction quenching on the raceway (11). S3. After quenching, the lifting worktable drives the frame to rise. When the spraying device moves to the position facing the roller (11), it stops rising and sprays quenching liquid onto the roller (11) to cool it. S4. After cooling is completed, the lifting worktable drives the frame to rise, so that the spraying device is completely separated from the outer ring (1) of the tapered roller bearing, and the raceway (11) quenching heat treatment is completed. In step S1, the cross-sectional shape of the lifting sleeve (8) is concave, and the sensor (2) can extend into the lifting sleeve (8). The outer ring (1) of the tapered roller bearing has an assembly mating surface (12). The connection between the assembly mating surface (12) and the raceway (11) is the boundary area (13). In step S2, when the sensor (2) corresponds to the raceway (11), the lower part of the sensor (2) protrudes out of the outer ring (1) of the tapered roller bearing, and the upper part of the sensor (2) is higher than the boundary area (13).

2. The method for induction hardening of the outer ring of a high-nitrogen stainless steel tapered roller bearing according to claim 1, characterized in that, The frame includes a fixed insulating plate (4), the fixed insulating plate (4) and the spray ring (3) are connected by a connecting assembly, the sensor (2) is sleeved on the outside of the connecting assembly, and the sensor (2) is connected to the connecting assembly by a positioning assembly.

3. The method for induction hardening of the outer ring of a high-nitrogen stainless steel tapered roller bearing according to claim 2, characterized in that, The connecting assembly includes multiple screws (5) disposed on the spray ring (3), and two locking nuts (51) are threaded on the screws (5). The screws (5) pass through the fixed insulating plate (4) and are clamped and fixed by the two locking nuts (51).

4. The method for induction hardening of the outer ring of a high-nitrogen stainless steel tapered roller bearing according to claim 3, characterized in that, The sensor (2) has multiple connecting plates (24) in its inner ring. The upper end of the connecting plate (24) is arranged with an upper insulating block (6) and a clamping nut (52) stacked from bottom to top. A lower insulating block (7) is provided between the connecting plate (24) and the spray ring (3). The screw (5) passes through the lower insulating block (7), the connecting plate (24), the upper insulating block (6) and the clamping nut (52) in sequence. The clamping nut (52) is threadedly engaged with the screw (5). The connecting plate (24) is provided with a positioning hole for the screw (5) to pass through. The lower end of the upper insulating block (6) is provided with an annular protrusion (61) that extends into the positioning hole and is inserted into the positioning hole.

5. The method for induction hardening of the outer ring of a high-nitrogen stainless steel tapered roller bearing according to claim 4, characterized in that, The sensor (2) also includes a sensor power board (22) connected to the sensor (2). The sensor power board (22) is located at the lower end of the fixed insulating plate (4). The upper and lower ends of the sensor (2) are respectively provided with magnetic conductors (23).

6. The method for induction hardening of the outer ring of a high-nitrogen stainless steel tapered roller bearing according to claim 1, characterized in that, In step S2, the frequency of induction hardening is 12-16 kHz, the power is 150-152 KW, the heating time is 4-10 s, and the rotation speed of the rotary table is 160 r / min-180 r / min; in step S3, the cooling time is 28-30 s.

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