A method for machining the inner ring of a bearing and its overrun groove

Abstract

This invention discloses a method for machining the inner ring of a bearing and its runout groove. The specific machining steps are as follows: Step 1: Technicians set the working parameters of the PLC controller, estimate the number of I / O points according to actual application requirements, consider appropriate margins, and test-run the CNC lathe; Step 2: The bar stock is clamped and fixed by a three-jaw chuck, and the PLC controller controls the milling cutter to cut off the excess outer edge of the bar stock so that the outer diameter of the bar stock is the required size of the bearing inner ring; Step 3: The cut bar stock is then axially cut into a shaft hole on a CNC lathe, with the hole diameter being the inner diameter of the bearing inner ring. The bar stock is then radially cut according to the required size to obtain the bearing inner ring blank; Step 4: The inner ring blank is mounted on a five-axis rotary table using a three-jaw chuck. Using a V-shaped vertical cutter to hard-machine the runout groove between the stepped surface and the bearing inner ring can minimize the turning blind zone and improve the machining efficiency and quality of the runout groove.

Description

Technical Field

[0001] This invention belongs to the field of bearing processing technology, specifically relating to a method for processing the inner ring of a bearing and its overrun groove. Background Technology

[0002] Bearings are essential components in modern machinery. Their primary function is to support rotating mechanical parts, reduce the coefficient of friction during movement, and ensure rotational accuracy. The bearing manufacturing process mainly includes raw material preparation, inner and outer ring machining, steel ball or roller machining, cage machining, and bearing assembly. A runout groove is typically provided between the stepped surface of the inner ring and the inner ring itself. This runout groove is an annular groove cut into a portion of the inner ring. This design primarily serves to optimize bearing performance and facilitate installation. The presence of the runout groove enhances the structural strength of the inner ring, reducing the likelihood of deformation and damage when facing large radial or axial forces. It requires specialized manufacturing methods for the bearing inner ring and its runout groove.

[0003] Existing methods for machining bearing inner rings and their runout grooves often result in blind spots during machining, leading to low machining efficiency, poor quality, inability to resist higher radial forces, weak deformation resistance, inconvenience in operation, and poor applicability. Summary of the Invention

[0004] The purpose of this invention is to provide a method for machining bearing inner rings and their runout grooves, in order to solve the problems mentioned in the background art regarding the existing methods for machining bearing inner rings and their runout grooves. These methods are prone to generating turning blind zones during the machining process, resulting in low machining efficiency and poor quality. Furthermore, they cannot resist higher radial forces, have insignificant anti-deformation effects, are inconvenient to operate, and have poor applicability.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a method for machining a bearing inner ring and its overrun groove, wherein the specific machining steps are as follows: Step 1: Technicians set the operating parameters of the PLC controller, estimate the number of I / O points according to the actual application requirements, consider appropriate margins, and conduct trial runs on the CNC lathe; Step 2: The bar stock is clamped and fixed by a three-jaw chuck, and the milling cutter is controlled by the PLC controller to cut off the excess outer edge of the bar stock so that the outer diameter of the bar stock is the required size of the inner ring of the bearing; Step 3: Next, use a CNC lathe to axially cut shaft holes into the cut bar stock. The hole diameter is the inner diameter of the bearing inner ring. Then, according to the required dimensions, radially cut the bar stock to obtain the bearing inner ring blank. Step 4: Mount the inner ring blank on the five-axis rotary table using a three-jaw chuck. Use a D-type end mill to machine steps, raceways, and flanges on both sides of the inner ring of the bearing inner ring blank. Use a C-type external turning cutter to machine the outer circle at the outer edge of the steps. Step 5: Next, use a C-type external turning tool to turn the end face of the bearing inner ring blank, then turn the outer circle, automatically adjust the dimensions with tool setting, use a Renishaw probe to measure the internal teeth and align the teeth position, and use a tooth scraper to forcefully scrape the teeth to form a gear groove on one side of the step. Step Six: Fine grind the inner ring plane of the bearing from Step Five, demagnetize the bearing, and then fine grind the outer diameter of the bearing, the inner diameter of the outer ring, the flange of the bearing, and the raceway of the bearing in sequence. Step 7: Make the inner diameter of the bearing inner ring contact with the fan-shaped surface of the chuck, and use a V-shaped vertical cutter to hard-machine the runout groove between the stepped surface and the bearing inner ring. Hard-machine parameters: cutting speed is 45m / min, feed rate is 0.02mm / r. Step 8: Place the processed bearing inner ring into an ultrasonic cleaner, add solvent for cleaning, and after a period of time, remove the bearing inner ring and place it on the worktable. Turn on the motor to drive the hard brush to rotate and clean the surface and gaps of the bearing inner ring. Step 9: Finally, place the cleaned bearing inner ring into an ultrasonic cleaner, add clean water for cleaning, and then dry the semi-finished bearing inner ring in a dryer at 65-85℃. Step 10: Use a high-frequency heating furnace to heat the surface of the bearing inner ring semi-finished product at the fastest possible heating speed, generally greater than 580℃ / second, to rapidly heat to 990℃~1100℃, and then quench it; after quenching, allow the bearing ring semi-finished product to cool naturally, thereby manufacturing the finished bearing inner ring with overrun groove.

[0006] Furthermore, in step one, the specific machine tool model used is the Hermle C52U five-axis linkage machining center, and in step five, the specific Renishaw probe model used is MH20i. The MH20i is suitable for the repeatable positioning probe base of the TP20 probe module.

[0007] Furthermore, in step two, the cutting speed is 90–100 m / min and the feed rate is 0.08–0.1 mm / r.

[0008] Furthermore, in step three, the cutting speed is 60–70 m / min and the feed rate is 0.02–0.03 mm / r.

[0009] Furthermore, in step eight, the bearing inner ring semi-finished product is placed in an ultrasonic cleaner, and solvent is added for 4 minutes of cleaning. In step nine, the bearing inner ring semi-finished product is placed in an ultrasonic cleaner, and water is added for 5 minutes of cleaning. The time for brushing the substrate surface with a hard brush should be 2 to 3 minutes.

[0010] Furthermore, in step ten, the surface temperature of the bearing inner ring semi-finished product must exceed the temperature range of the austenitic region, i.e., 723℃~830℃.

[0011] Furthermore, in step ten, the quenching treatment involves spraying a quenching medium for crystallization annealing for 50-80 minutes followed by multiple unidirectional rolling processes, with each unidirectional rolling process having an equivalent variable of 1.8-3.

[0012] Compared with the prior art, the beneficial effects of the present invention are: (1) The method for machining the bearing inner ring and its overrun groove uses a D-type end mill to machine steps, raceways and flanges on both sides of the bearing inner ring blank. It does not require multiple clamping of the workpiece. The double-sided steps can improve the bearing inner ring's resistance to higher radial forces and significantly enhance its anti-deformation effect. Power scraping is an efficient gear machining method that combines hobbing and gear shaping processes. It allows for high-speed continuous cutting on a five-axis machine tool. Its main advantages are high productivity and flexibility, which improves the production efficiency of bearing inner rings. The resulting bearing inner ring is hardened to achieve grain refinement, obtain high strength characteristics, greatly improve yield strength, is not easily deformed, and is durable, effectively extending the service life of the bearing ring.

[0013] (2) The method for machining the inner ring of a bearing and its overrun groove. The Renishaw probe is known for its high precision and repeatability. It can measure at multiple angles and reposition without recalibration, thereby saving operation time and improving measurement accuracy. The produced gear groove is easy to use with the active bevel gear, expanding the application range. The overrun groove is hard-machined between the step surface and the inner ring of the bearing using a V-shaped vertical cutter, which can minimize the turning blind zone and improve the machining efficiency and quality of the overrun groove. Before quenching, the surface and gap of the inner ring of the bearing are cleaned by an ultrasonic cleaner, which has a high cleaning effect and avoids the surface metal particles from adhering to the workpiece surface at high temperature, affecting product quality. The overall production steps are easy to operate, highly creative, and suitable for widespread use. Detailed Implementation

[0014] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0015] A method for machining the inner ring of a bearing and its runout groove, the specific machining steps are as follows: Step 1: Technicians set the operating parameters of the PLC controller, estimate the number of I / O points according to the actual application requirements, consider appropriate margins, and conduct trial runs on the CNC lathe; Step 2: The bar stock is clamped and fixed by a three-jaw chuck, and the milling cutter is controlled by the PLC controller to cut off the excess outer edge of the bar stock so that the outer diameter of the bar stock is the required size of the inner ring of the bearing; Step 3: Next, use a CNC lathe to axially cut shaft holes into the cut bar stock. The hole diameter is the inner diameter of the bearing inner ring. Then, according to the required dimensions, radially cut the bar stock to obtain the bearing inner ring blank. Step 4: Mount the inner ring blank on the five-axis rotary table using a three-jaw chuck. Use a D-type end mill to machine steps, raceways, and flanges on both sides of the inner ring of the bearing inner ring blank. Use a C-type external turning cutter to machine the outer circle at the outer edge of the steps. Step 5: Next, use a C-type external turning tool to turn the end face of the bearing inner ring blank, then turn the outer circle, automatically adjust the dimensions with tool setting, use a Renishaw probe to measure the internal teeth and align the teeth position, and use a tooth scraper to forcefully scrape the teeth to form a gear groove on one side of the step. Step Six: Fine grind the inner ring plane of the bearing from Step Five, demagnetize the bearing, and then fine grind the outer diameter of the bearing, the inner diameter of the outer ring, the flange of the bearing, and the raceway of the bearing in sequence. Step 7: Make the inner diameter of the bearing inner ring contact with the fan-shaped surface of the chuck, and use a V-shaped vertical cutter to hard-machine the runout groove between the stepped surface and the bearing inner ring. Hard-machine parameters: cutting speed is 45m / min, feed rate is 0.02mm / r. Step 8: Place the processed bearing inner ring into an ultrasonic cleaner, add solvent for cleaning, and after a period of time, remove the bearing inner ring and place it on the worktable. Turn on the motor to drive the hard brush to rotate and clean the surface and gaps of the bearing inner ring. Step 9: Finally, place the cleaned bearing inner ring into an ultrasonic cleaner, add clean water for cleaning, and then dry the semi-finished bearing inner ring in a dryer at 65-85℃. Step 10: Use a high-frequency heating furnace to heat the surface of the bearing inner ring semi-finished product at the fastest possible heating speed, generally greater than 580℃ / second, to rapidly heat to 990℃~1100℃, and then quench it; after quenching, allow the bearing ring semi-finished product to cool naturally, thereby manufacturing the finished bearing inner ring with overrun groove.

[0016] In step one, the specific machine tool model used is the Hermle C52U five-axis linkage machining center, and in step five, the specific Renishaw probe model used is MH20i. MH20i is suitable for the repeatable positioning probe base of the TP20 probe module.

[0017] In step two, the cutting speed is 90-100 m / min and the feed rate is 0.08-0.1 mm / r.

[0018] In step three, the cutting speed is 60-70 m / min and the feed rate is 0.02-0.03 mm / r.

[0019] In step eight, the bearing inner ring semi-finished product is placed in an ultrasonic cleaner, and solvent is added for 4 minutes of cleaning. In step nine, the bearing inner ring semi-finished product is placed in an ultrasonic cleaner, and water is added for 5 minutes of cleaning. The time for brushing the substrate surface with a hard brush should be 2 to 3 minutes.

[0020] In step ten, the surface temperature of the bearing inner ring semi-finished product must be heated to exceed the temperature range of the austenitic region, i.e., 723℃~830℃.

[0021] In step ten, the quenching process involves spraying a quenching medium for crystallization annealing for 50-80 minutes followed by multiple unidirectional rolling processes. The equivalent variable for each unidirectional rolling process is 1.8-3.

[0022] In operation, this invention utilizes a D-type end mill to machine steps, raceways, and flanges on both sides of the inner ring of the bearing inner ring blank, eliminating the need for multiple workpiece clamping. The double-sided steps enhance the bearing inner ring's resistance to higher radial forces and significantly improve its deformation resistance. Powerful gear scraping is a highly efficient gear machining method that combines hobbing and gear shaping processes, allowing for high-speed continuous cutting on a five-axis machine tool. Its main advantages lie in its high productivity and flexibility, improving the production efficiency of bearing inner rings. The resulting bearing inner ring undergoes quenching treatment, achieving grain refinement, high strength characteristics, significantly increased yield strength, reduced deformation, and durability, effectively extending the service life of the bearing rings. Renishaw probes are renowned for their high precision and repeatability, capable of measuring at multiple angles and repositioning without recalibration, saving operation time and improving measurement accuracy. The resulting gear grooves are easily integrated with drive bevel gears, expanding their application range. Using a V-shaped vertical cutter to hard-machine runout grooves between the stepped surface and the bearing inner ring minimizes blind spots, improving machining efficiency and quality. Before quenching, ultrasonic cleaning of the bearing inner ring surface and gaps ensures high cleaning effectiveness and prevents surface metal particles from adhering to the workpiece surface at high temperatures, thus affecting product quality. The overall production process is easy to operate, highly innovative, and suitable for widespread use.

[0023] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for machining the inner ring of a bearing and its overrun groove, characterized in that, The specific processing steps are as follows: Step 1: Technicians set the operating parameters of the PLC controller, estimate the number of I / O points according to the actual application requirements, consider appropriate margins, and conduct trial runs on the CNC lathe; Step 2: The bar stock is clamped and fixed by a three-jaw chuck, and the milling cutter is controlled by the PLC controller to cut off the excess outer edge of the bar stock so that the outer diameter of the bar stock is the required size of the inner ring of the bearing; Step 3: Next, use a CNC lathe to axially cut shaft holes into the cut bar stock. The hole diameter is the inner diameter of the bearing inner ring. Then, according to the required dimensions, radially cut the bar stock to obtain the bearing inner ring blank. Step 4: Mount the inner ring blank on the five-axis rotary table using a three-jaw chuck. Use a D-type end mill to machine steps, raceways, and flanges on both sides of the inner ring of the bearing inner ring blank. Use a C-type external turning cutter to machine the outer circle at the outer edge of the steps. Step 5: Next, use a C-type external turning tool to turn the end face of the bearing inner ring blank, then turn the outer circle, automatically adjust the dimensions with tool setting, use a Renishaw probe to measure the internal teeth and align the teeth position, and use a tooth scraper to forcefully scrape the teeth to form a gear groove on one side of the step. Step Six: Fine grind the inner ring plane of the bearing from Step Five, demagnetize the bearing, and then fine grind the outer diameter of the bearing, the inner diameter of the outer ring, the flange of the bearing, and the raceway of the bearing in sequence. Step 7: Make the inner diameter of the bearing inner ring contact with the fan-shaped surface of the chuck, and use a V-shaped vertical cutter to hard-machine the runout groove between the stepped surface and the bearing inner ring. Hard-machine parameters: cutting speed is 45m / min, feed rate is 0.02mm / r. Step 8: Place the processed bearing inner ring into an ultrasonic cleaner, add solvent for cleaning, and after a period of time, remove the bearing inner ring and place it on the worktable. Turn on the motor to drive the hard brush to rotate and clean the surface and gaps of the bearing inner ring. Step 9: Finally, place the cleaned bearing inner ring into an ultrasonic cleaner, add clean water for cleaning, and then dry the semi-finished bearing inner ring in a dryer at 65-85℃. Step 10: Use a high-frequency heating furnace to heat the surface of the bearing inner ring semi-finished product at the fastest possible heating speed, greater than 580℃ / second, to rapidly heat to 990℃~1100℃, and then quench it; after quenching, allow the bearing ring semi-finished product to cool naturally, thereby manufacturing the finished bearing inner ring with overrun groove.

2. The method for machining a bearing inner ring and its overrun groove according to claim 1, characterized in that: In step one, the specific machine tool model used is the Hermle C52U five-axis linkage machining center. In step five, the specific Renishaw probe model used is MH20i. MH20i is suitable for the repeatable positioning probe base of the TP20 probe module.

3. The method for machining a bearing inner ring and its overrun groove according to claim 1, characterized in that: In step two, the cutting speed is 90-100 m / min and the feed rate is 0.08-0.1 mm / r.

4. The method for machining a bearing inner ring and its overrun groove according to claim 1, characterized in that: In step three, the cutting speed is 60-70 m / min and the feed rate is 0.02-0.03 mm / r.

5. The method for machining a bearing inner ring and its overrun groove according to claim 1, characterized in that: In step eight, the bearing inner ring semi-finished product is placed in an ultrasonic cleaner, and solvent is added for 4 minutes of cleaning. In step nine, the bearing inner ring semi-finished product is placed in an ultrasonic cleaner, and water is added for 5 minutes of cleaning. The time for brushing the substrate surface with a hard brush should be 2 to 3 minutes.

6. The method for machining a bearing inner ring and its overrun groove according to claim 1, characterized in that: In step ten, the surface temperature of the bearing inner ring semi-finished product must be heated to exceed the temperature range of the austenitic region, i.e., 723℃~830℃.

7. The method for machining a bearing inner ring and its overrun groove according to claim 1, characterized in that: In step ten, the quenching process involves spraying a quenching medium for crystallization annealing for 50-80 minutes, followed by multiple unidirectional rolling processes. The equivalent variable for each unidirectional rolling process is 1.8-3.