Four-point contact ball rotary table bearing raceway processing tool and processing method

Abstract

The application discloses a four-point contact ball rotary disc bearing raceway machining tool and a machining method, which comprises a platform, a bearing outer ring to be machined, an upper half pre-tightening inner ring and a lower half pre-tightening inner ring; the upper half pre-tightening inner ring and the lower half pre-tightening inner ring are connected together through pre-tightening force screws, and a guide pin is arranged between the upper half pre-tightening inner ring and the lower half pre-tightening inner ring; the four-point contact ball rotary disc bearing raceway machining tool and the machining method gradually pressurize the bearing raceway through the designed tool mechanism, the rolling body steel ball is subjected to the grinding and surface cold rolling process on the raceway, the micro quality of the surface of the bearing raceway and the raceway profile are improved, the roughness problem is solved, the corrugation of the raceway is greatly improved, the formed raceway contact state, tightness and other indexes are closer to the actual application working condition through the micro improvement and surface extrusion deformation of the surface, and the running stiffness, stability and fatigue life of the bearing are improved.

Description

Technical Field

[0001] This application relates to the field of machining technology for improving the waviness and roughness of raceways in four-point contact ball slewing bearings, specifically to machining tooling and machining methods for raceways of four-point contact ball slewing bearings. Background Technology

[0002] Four-point contact ball slewing bearings are a common and widely used type of slewing bearing, widely used in various engineering machinery and equipment. However, in some high-end applications, such as medical CT, MRI, and precision turntables, there are strict requirements for noise and vibration control during high-speed applications. The existing four-point contact ball slewing bearing products have a low qualification rate, and the failure rate and rework rate of the applied products are high, which has become a bottleneck in the manufacturing of high-end equipment.

[0003] Bearing noise is mainly determined by the roughness, waviness, and roundness of the bearing rings, as well as the precision of the rolling elements and cage. Currently, the industry has sufficient capability to solve the problem of high-precision rolling element bearing processing. However, there are still significant technical and process bottlenecks in the processing precision of large-diameter bearing rings. Moreover, the processing of existing large-diameter bearing rings requires the use of high-end grinding and ultra-precision grinding machines, which involves complex operation processes. At the same time, the bearing rings manufactured in this way have large errors in roundness, waviness, and roughness, which has a significant impact on the control of bearing noise and vibration. Summary of the Invention

[0004] This application provides a machining fixture and method for the raceway of a four-point contact ball slewing bearing. The designed fixture mechanism applies progressive pressure to the bearing raceway, causing the rolling steel balls to grind and cold roll the raceway surface. This process improves the microscopic quality and raceway profile of the bearing raceway surface, not only solving the roughness problem but also significantly improving the raceway waviness. Furthermore, through microscopic surface improvement and surface extrusion deformation, the resulting raceway contact state and tightness indicators are closer to actual application conditions, improving the bearing's operating stiffness, stability, and fatigue life. Moreover, the surface quality of the machined raceway is superior to that of precision grinding and ultra-precision grinding, effectively solving the problems in the prior art.

[0005] To achieve the above objectives, this application provides the following technical solution: a four-point contact ball swivel bearing raceway machining fixture, including a platform, the outer ring of the bearing to be machined, an upper preloaded inner ring, and a lower preloaded inner ring; the upper preloaded inner ring and the lower preloaded inner ring are connected together by preload screws, and a guide pin is provided between the upper preloaded inner ring and the lower preloaded inner ring.

[0006] The upper and lower preloaded inner rings are connected by preload screws to form a single simulated inner ring, which is then assembled with the outer ring of the bearing being machined and the rolled steel balls.

[0007] After assembly, a reserved gap is designed between the upper half preloaded inner ring and the lower half preloaded inner ring. Axial force is applied by the preload tightening screw to form pressure between the rolled steel ball and the raceway of the machined bearing outer ring.

[0008] The lower preloaded inner ring is fixed to the platform by connecting screws and connecting sliders.

[0009] A motor is installed on the platform, and the output shaft of the motor is connected to a drive gear. The outer ring of the machined bearing is connected to the gear plate by connecting screws, and the drive gear meshes with the gear plate.

[0010] Preferably, the number of guide pins is not less than two, and the not less than two guide pins are circumferentially distributed between the upper half of the preload inner ring and the lower half of the preload inner ring.

[0011] Preferably, the platform is provided with an X-shaped slide rail, and four sliders are evenly distributed inside the X-shaped slide rail. The sliders are connected to the lower half of the pre-tightening inner ring.

[0012] Preferably, a sealing ring is provided on the outer side of the lower half preloaded inner ring near the outer ring of the machined bearing.

[0013] The method for machining the raceway of a four-point contact ball slewing bearing utilizes the aforementioned machining fixtures for the raceway of a four-point contact ball slewing bearing, including:

[0014] Step 1: Install the outer ring of the bearing to be machined, which requires raceway precision grinding, onto the four-point contact ball slewing bearing raceway machining fixture.

[0015] Step 2: Fill the raceway of the outer ring of the bearing being machined with grinding grease.

[0016] Step 3: Apply pressure for the first time by tightening the preload screw. After the pressure is applied, start the motor to drive the gear plate to rotate. The gear plate drives the outer ring of the bearing to be processed to rotate, and the rolling steel balls perform rotary rolling and grinding on the raceway.

[0017] Step 4: After the first pressurized rotary rolling and grinding, the outer ring of the bearing to be machined is removed, and then its raceway roughness and waviness are measured.

[0018] Step 5: Adjust the pressure of the pre-tightening screw according to the measurement results in Step 4, and then perform a second pressurized rotary rolling and grinding.

[0019] Step Six: Repeat Steps Four and Five until the raceway roughness and waviness meet the standards.

[0020] Compared with the prior art, the beneficial effects of this application are:

[0021] 1. This four-point contact ball slewing bearing raceway machining fixture and machining method uses a designed fixture mechanism to gradually pressurize the bearing raceway, causing the rolling steel balls to grind and cold roll the raceway surface. This process improves the microscopic quality and raceway profile of the bearing raceway surface, not only solving the roughness problem but also significantly improving the waviness of the raceway. Furthermore, through microscopic surface improvement and surface extrusion deformation, the resulting raceway contact state, tightness, and other indicators will be closer to the actual application conditions, improving the bearing's running stiffness, stability, and fatigue life. Moreover, the surface quality of the machined raceway is superior to that of precision grinding and ultra-precision grinding of the raceway.

[0022] 2. This process applies a preload to the outer ring and rolling elements of the bearing, thereby improving the roughness and waviness of the raceway of the outer ring under certain pressure through grinding and rolling of the rolling elements. The raceway rolled and ground by this process will have improved contact and tightness with the steel balls, conforming to the contact state under actual working conditions, thus improving the smoothness of operation. The design ensures that there is a certain gap between the mating surfaces of the upper and lower preloaded inner rings after assembly, which guarantees the transmission of the tension of the preload screw during operation.

[0023] 3. The upper and lower preloaded inner rings are guided and positioned by four circumferentially distributed guide pins to prevent misalignment and ensure the balance of circumferential force. The rolling force of the bearing outer ring raceway is applied in stages by the preload screws as the rolling surface quality profile changes. The upper and lower preloaded inner rings are made of GCr15SiMn material with a hardness ≥60HRC to ensure long service life and high surface strength. The drive gear and gear plate are made of PA66, which has good vibration damping and impact reduction effects, improving the rolling and grinding quality of the machined bearing outer ring 5. Attached Figure Description

[0024] Figure 1 This is a cross-sectional view of this application;

[0025] Figure 2 This is a top view of this application;

[0026] Figure 3 This is a diagram showing the clearance between the mating surfaces of the upper and lower preloaded inner rings after assembly.

[0027] In the diagram: 1 platform, 2 drive motor, 3 drive gear, 4 gear disc, 5 outer ring of the machined bearing, 6 connecting screw, 7 rolled steel ball, 8 preload screw, 9 upper preload inner ring, 10 guide pin, 11 sealing ring, 12 lower preload inner ring, 13 connecting screw, 14 connecting slider. Detailed Implementation

[0028] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0029] In the description of this application, when a feature is referred to as "setting", "fixing", or "connecting" to another feature, it can be set, fixed, or connected to the other feature directly, or it can be set, fixed, or connected to the other feature indirectly.

[0030] Please see Figure 1-3 This application provides the following technical solution: a four-point contact ball swivel bearing raceway machining fixture, including a platform 1, a bearing outer ring 5 to be machined, an upper preloaded inner ring 9 and a lower preloaded inner ring 12; the upper preloaded inner ring 9 and the lower preloaded inner ring 12 are connected together by a preload screw 8, and a guide pin 10 is provided between the upper preloaded inner ring 9 and the lower preloaded inner ring 12.

[0031] Specifically, the upper preload inner ring 9 and the lower preload inner ring 12 are connected and axially stressed by the preload screw 8, and are precisely positioned by four circumferentially distributed guide pins 10.

[0032] The upper preloaded inner ring 9 and the lower preloaded inner ring 12 are connected by a preload screw 8 to form an integral simulated inner ring, which is then assembled with the outer ring 5 of the bearing being machined and the rolled steel ball 7.

[0033] After assembly, a reserved gap is designed between the upper half preloaded inner ring 9 and the lower half preloaded inner ring 12. Axial force is applied by the preload tightening screw 8, forming pressure between the rolled steel ball 7 and the raceway of the machined bearing outer ring 5.

[0034] The lower pre-tightened inner ring 12 is fixed to the platform 1 by connecting screws 13 and connecting sliders 14.

[0035] Specifically, platform 1 can be used to process bearing outer rings of different sizes.

[0036] A motor 2 is installed on platform 1. The output shaft of motor 2 is connected to a drive gear 3. The outer ring 5 of the machined bearing is connected to the gear plate 4 by a connecting screw 6. The drive gear 3 meshes with the gear plate 4.

[0037] Furthermore, the number of guide pins 10 is no less than two, and the no less than two guide pins 10 are circumferentially distributed between the upper half preload inner ring 9 and the lower half preload inner ring 12.

[0038] Specifically, there are four guide pins 10, which are evenly distributed in a ring between the upper preload inner ring 9 and the lower preload inner ring 12.

[0039] Furthermore, the platform 1 is provided with an X-shaped slide rail, and four sliders 14 are evenly distributed inside the X-shaped slide rail. The sliders 14 are connected to the lower half of the pre-tightening inner ring 12.

[0040] Specifically, the X-shaped slide rail, together with the four sliders 14 on its four rails, can be used to fix the lower half preloaded inner ring 12 of different sizes.

[0041] Furthermore, a sealing ring 11 is provided on the outer side of the lower preload inner ring 12 near the outer ring 5 of the machined bearing.

[0042] Specifically, the sealing ring 11 prevents the abrasive from leaking between the outer ring 5 of the bearing being machined and the lower preloaded inner ring 12 during operation.

[0043] The method for machining the raceway of a four-point contact ball slewing bearing utilizes the aforementioned machining fixtures for the raceway of a four-point contact ball slewing bearing, including:

[0044] Step 1: Install the outer ring 5 of the bearing to be machined, which requires raceway precision grinding, onto the four-point contact ball slewing bearing raceway machining fixture.

[0045] Step 2: Fill the raceway of the outer ring 5 of the bearing being machined with grinding grease.

[0046] Step 3: Apply pressure for the first time by tightening the preload screw 8. After the pressure is applied, the motor 2 starts and drives the gear plate 4 to rotate. The gear plate 4 drives the outer ring 5 of the bearing to be processed to rotate, and the rolling steel balls 7 perform rotary rolling and grinding on the raceway.

[0047] Step 4: After the first pressurized rotary rolling and grinding, the outer ring 5 of the bearing to be machined is removed, and then its raceway roughness and waviness are measured.

[0048] Step 5: Adjust the pressure of the pre-tightening screw 8 according to the measurement results in Step 4, and then perform a second pressurized rotary rolling and grinding.

[0049] Step Six: Repeat Steps Four and Five until the raceway roughness and waviness meet the standards.

[0050] Specifically, this process applies a preload to the outer ring and rolling elements of the bearing, thereby improving the roughness and waviness of the raceway of the outer ring under certain pressure through grinding and rolling of the rolling elements.

[0051] The raceway, produced by this rolling and grinding process, will have improved contact and tightness with the steel balls, conforming to the contact condition under actual working conditions and improving operational stability.

[0052] The upper preload inner ring 9 and the lower preload inner ring 12 have a certain gap after assembly. This gap can ensure the transmission of the tensile force of the preload screw 8 during operation.

[0053] The design incorporates four circumferentially distributed guide pins 10 to guide and position the upper preloaded inner ring 9 and the lower preloaded inner ring 12, preventing misalignment of the rings and ensuring the balance of the circumferential force.

[0054] The rolling force of the bearing outer ring raceway is applied in stages by the preload screw 8 as the rolling surface quality profile changes;

[0055] The upper preload inner ring 9 and the lower preload inner ring 12 are made of GCr15SiMn material with a hardness ≥60HRC to ensure long service life and high surface strength.

[0056] The drive gear 3 and the gear disc 4 are made of PA66, which has a good damping and impact reduction effect, and improves the rolling and grinding quality of the outer ring 5 of the machined bearing.

[0057] In use: The outer ring 5 of the bearing to be processed is assembled onto the platform 1. The drive motor 2 drives the outer ring 5 of the bearing to be processed to rotate through the gear transmission mechanism. The axial tension is gradually applied to the upper half preloaded inner ring 9 and the lower half preloaded inner ring 12 by the preload screw 8. Since there is a reserved gap between the upper half preloaded inner ring 9 and the lower half preloaded inner ring 12, the upper half preloaded inner ring 9 and the lower half preloaded inner ring 12 will apply a preload to the rolling steel ball 7. At this time, the rolling steel ball 7 applies a preload to the raceway of the outer ring 5 of the bearing to be processed. This allows the raceway of the outer ring 5 of the bearing to be processed to rotate under preload, so as to achieve preloaded rolling and grinding.

[0058] Although embodiments of this application have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A tooling for machining the raceway of a four-point contact ball slewing bearing, characterized in that: It includes a platform (1), a bearing outer ring (5) to be processed, an upper preload inner ring (9) and a lower preload inner ring (12); the upper preload inner ring (9) and the lower preload inner ring (12) are connected together by a preload screw (8), and a guide pin (10) is provided between the upper preload inner ring (9) and the lower preload inner ring (12). The upper half preloaded inner ring (9) and the lower half preloaded inner ring (12) are connected by a preload screw (8) to form an integral simulated inner ring, which is then assembled with the outer ring (5) of the bearing to be machined and the rolled steel ball (7). After assembly, a reserved gap is designed between the upper half preloaded inner ring (9) and the lower half preloaded inner ring (12). Axial force is applied by the preload tightening screw (8) to form pressure between the rolled steel ball (7) and the raceway of the machined bearing outer ring (5). The lower half pre-tightened inner ring (12) is fixed to the platform (1) by connecting screws (13) and connecting sliders (14); A motor (2) is installed on the platform (1). The output shaft of the motor (2) is connected to a drive gear (3). The outer ring (5) of the machined bearing is connected to the gear plate (4) by a connecting screw (6). The drive gear (3) meshes with the gear plate (4).

2. The tooling for machining the raceway of a four-point contact ball slewing bearing according to claim 1, characterized in that: The number of guide pins (10) is no less than two, and the guide pins (10) are circumferentially distributed between the upper half preload inner ring (9) and the lower half preload inner ring (12).

3. The machining fixture for the raceway of a four-point contact ball slewing bearing according to claim 1, characterized in that: The platform (1) is provided with an X-shaped slide rail, and four sliders (14) are evenly distributed inside the X-shaped slide rail. The sliders (14) are connected to the lower half pre-tightening inner ring (12).

4. The tooling for machining the raceway of a four-point contact ball slewing bearing according to claim 1, characterized in that: A sealing ring (11) is provided on the outer side of the lower half preloaded inner ring (12) near the outer ring (5) of the bearing being machined.

5. A method for machining the raceway of a four-point contact ball slewing bearing, using the machining fixture for the raceway of a four-point contact ball slewing bearing as described in any one of claims 1 to 4, characterized in that, include: Step 1: Install the outer ring (5) of the bearing to be machined, which requires raceway fine grinding, onto the four-point contact ball slewing bearing raceway machining fixture; Step 2: Fill the raceway of the outer ring (5) of the bearing being machined with grinding grease; Step 3: Apply pressure for the first time by tightening the pre-tightening screw (8). After the pressure is applied, the motor (2) is started to drive the gear plate (4) to rotate. The gear plate (4) drives the outer ring (5) of the bearing to be processed to rotate. The rolling steel ball (7) performs rotary rolling and grinding on the raceway. Step 4: After the first pressurized rotary rolling and grinding, the outer ring (5) of the bearing to be machined is removed, and then its raceway roughness and waviness are measured. Step 5: Adjust the pressure of the pre-tightening screw (8) according to the measurement results of Step 4, and then perform a second pressurized rotary rolling and grinding; Step Six: Repeat Steps Four and Five until the raceway roughness and waviness meet the standards.

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