Machining method for extra-large ball loading notch on outer ring of thin-walled bearing

Abstract

This invention relates to the field of bearing machining and relates to a method for machining extra-large ball loading notches on the outer ring of thin-walled bearings. The invention addresses the technical problems in current bearing machining, such as large grinding amounts, poor dimensional consistency, impact on locking point height control, low machining efficiency, poor quality, and deformation during subsequent machining. The method involves: precision grinding of the outer raceway, hard milling of the notch, supplementary tempering, grinding of the notch, and removal of the notch's sharp angles. This invention effectively solves the problem of unstable control over raceway accuracy and locking point dimensions due to extra-large notches, improving both product quality and consistency. Because hard milling provides better control over milling force, subsequent tempering does not cause deformation, ensuring product quality. This invention is used for machining extra-large ball loading notches on the outer ring of thin-walled bearings.

Description

Technical Field

[0001] This invention relates to the field of bearing machining. Background Technology

[0002] According to requirements, the outer ring of a certain type of bearing has an arc locking point height of 0.2–0.25 mm, a notch radius of 12 mm, a radial depth slightly exceeding half the ring wall thickness, an axial height close to half the outer ring width, and a maximum chord length of 19 mm at the notch. Because the ring is a thin and light series, the excessively large notch necessitates linear interpolation hard milling, which results in high machining resistance. During subsequent machining, stress release can easily lead to deformation, exceeding ellipticity tolerances, and producing waste products. Furthermore, the wear of the tool radius curvature R causes significant changes in the radius of curvature, affecting subsequent notch grinding. This results in technical problems such as large grinding volume, poor dimensional consistency, difficulty in controlling the locking point height, low machining efficiency, and poor quality. Summary of the Invention

[0003] This invention addresses the technical problems in current bearing processing, such as large grinding volume, poor dimensional consistency, impact on locking point height control, low processing efficiency, poor quality, and deformation during subsequent processing. It provides a method for machining ultra-large ball loading notches on the outer ring of thin-walled bearings.

[0004] The machining method for the extra-large ball filling notch on the outer ring of a thin-walled bearing is carried out according to the following steps:

[0005] 1. Grind the outer raceway of the bearing workpiece.

[0006] 2. After the bearing workpiece is processed in step one, the notch is hard-milled using the helical interpolation milling method. The tool is a D16 carbide end mill. First, the tool is brought to the machining starting point, then tilted at a 4° angle. The helical interpolation milling program is used. The tool interpolates in the plane and moves out of an arc with a radius of 12mm. At the same time, it slowly descends along the Z-axis to the machining end point, and then returns to the initial position.

[0007] Third, perform supplementary tempering on the bearing workpiece after step two, controlling the tempering temperature to be 125-135℃.

[0008] 4. Grind the bearing workpiece after step 3 to make it notch, and control the grinding wheel linear speed to be 20-25m / s, the transverse feed speed to be 2-3μm / s, and the number of reciprocating cycles of the worktable to be 120-180 times / min.

[0009] 5. Remove the notches and sharp angles from the bearing workpiece processed in step 4 to complete the process.

[0010] Furthermore, step two involves hard milling the notch at a machining center.

[0011] Furthermore, the cutting length of the tool described in step two is 25mm.

[0012] Further, in step two, set the CNC machining program parameters: spindle clockwise rotation, speed 1000 r / min, feed 40 mm / min; tool returns to the program starting point, 100 mm from the workpiece plane; tool rotates 4° around the Y-axis; coordinate system rotates 4° around the Y-axis; tool rapidly approaches the entry point, entry point coordinates X 38, Y 0, Z 3.2; tool rotates clockwise, performing 20 full circles in a spiral pattern from the starting position, 0.45 mm per circle, milling to the Z-6X80 position; tool returns to the program starting point, program ends.

[0013] Furthermore, in step three, the tempering temperature is controlled at 130℃.

[0014] Furthermore, in step four, a notching machine is used to grind the notch.

[0015] Furthermore, in step four, the grinding amount is controlled to be 0.05 mm.

[0016] Furthermore, in step four, the locking ball height of the channel and the notch is controlled to be 0.05–0.2 mm.

[0017] Furthermore, step four uses an MA80KV grinding wheel.

[0018] Beneficial effects of this invention:

[0019] Currently, the common machining method for thin-walled bearings is soft milling followed by heat treatment and then grinding the notch. Due to the large notch, stress release at the notch during heat treatment is significant, leading to large elliptical deformation. This affects subsequent groove grinding and finishing, causing intermittent grinding and finishing, resulting in groove accuracy and dimensional deviations. The present invention, which uses hard milling after finishing the groove, effectively solves the problem of intermittent cutting. However, it places high demands on the hard milling of the notch, requiring strict control of the cutting force generated by hard milling to ensure no deformation occurs.

[0020] This invention employs a carbide end mill and utilizes a helical interpolation milling method for machining. This method differs from traditional linear interpolation; it uses only the bottom edge of the end mill for cutting, resulting in high cutting force. Helical milling uses the side edge of the end mill, maintaining a constant cutting speed. The end mill radius is smaller than the notch radius. Simultaneously, linear interpolation feed is performed axially while circular interpolation is conducted, with each axial depth of cut being 0.45mm. The workpiece experiences minimal axial and radial forces, preventing milling deformation and controlling dimensional tolerances within 0.05mm, minimizing variation and preparing for subsequent grinding. The milling clamping method uses outer diameter and end face positioning; the end face clamping method prevents clamping deformation.

[0021] Experimental verification shows that the thin-walled bearings processed using the method of this invention reduce the amount of grinding during the machining process, improve the consistency of the locking point height dimensions, ensure that all dimensions and ovality of the outer ring are within acceptable limits, and meet the appearance quality requirements. It solves the problem of deformation caused by notches, achieving a product qualification rate of over 95%, providing a reference for future processing of products with similar structures. This invention effectively solves the problem of unstable control of groove accuracy and locking point dimensions due to ultra-large notches, improving both product quality and consistency. Because hard milling provides better control of the milling force, subsequent tempering does not cause deformation, ensuring product quality.

[0022] This invention is used for machining extra-large ball loading notches on the outer ring of thin-walled bearings. Attached Figure Description

[0023] Figure 1 This is a photograph of the actual object of the machined thin-walled bearing outer ring with an extra-large ball filling notch, as shown in Example 1.

[0024] Figure 2 This is a simplified diagram of the outer ring structure of the thin-walled bearing with an extra-large ball loading notch, as shown in Example 1.

[0025] Figure 3 for Figure 2 A simplified diagram of the local structure in direction A. Detailed Implementation

[0026] Specific Implementation Method 1: This implementation method differs from Specific Implementation Method 1 in that the method for machining the extra-large ball loading notch on the outer ring of a thin-walled bearing is characterized by the following steps:

[0027] 1. Grind the outer raceway of the bearing workpiece.

[0028] 2. After the bearing workpiece is processed in step one, the notch is hard-milled using the helical interpolation milling method. The tool is a D16 carbide end mill. First, the tool is brought to the machining starting point, then tilted at a 4° angle. The helical interpolation milling program is used. The tool interpolates in the plane and moves out of an arc with a radius of 12mm. At the same time, it slowly descends along the Z-axis to the machining end point, and then returns to the initial position.

[0029] Third, perform supplementary tempering on the bearing workpiece after step two, controlling the tempering temperature to be 125-135℃.

[0030] 4. Grind the bearing workpiece after step 3 to make it notch, and control the grinding wheel linear speed to be 20-25m / s, the transverse feed speed to be 2-3μm / s, and the number of reciprocating cycles of the worktable to be 120-180 times / min.

[0031] 5. Remove the notches and sharp angles from the bearing workpiece processed in step 4 to complete the process.

[0032] Specific Implementation Method Two: This implementation method differs from Specific Implementation Method One in that step two, the hard milling of the notch, is performed in a machining center. Everything else is the same as in Specific Implementation Method One.

[0033] Specific Implementation Method Three: This implementation method differs from Specific Implementation Method One or Two in that the cutting length of the tool described in step two is 25mm. Everything else is the same as in Specific Implementation Method One or Two.

[0034] Specific Implementation Method Four: This implementation method differs from Specific Implementation Methods One to Three in the following ways: Step Two sets the CNC machining program parameters: spindle clockwise rotation, speed 1000 r / min, feed 40 mm / min; tool returns to the program starting point, 100 mm from the workpiece plane; tool rotates 4° around the Y-axis; coordinate system rotates 4° around the Y-axis; tool rapidly approaches the entry point, entry point coordinates X38, Y0, Z3.2; tool rotates clockwise, performing 20 full circles in a helical pattern from the starting position, 0.45 mm per circle, milling to the Z-6X80 position; tool returns to the program starting point, program ends. Everything else is the same as in Specific Implementation Methods One to Three.

[0035] Specific Implementation Method Five: This implementation method differs from Specific Implementation Methods One to Four in that the tempering temperature in step three is controlled at 130°C. Everything else is the same as in Specific Implementation Methods One to Four.

[0036] Specific Implementation Method Six: This implementation method differs from Specific Implementation Methods One to Five in that step four involves using a notching machine to grind the notch. Everything else is the same as in Specific Implementation Methods One to Five.

[0037] Specific Implementation Method Seven: This implementation method differs from Specific Implementation Methods One to Six in that: in step four, the grinding amount is controlled to be 0.05 mm. Everything else is the same as in Specific Implementation Methods One to Six.

[0038] Specific Implementation Method Eight: This implementation method differs from Specific Implementation Methods One to Seven in that: in step four, the height of the locking ball between the channel and the notch is controlled to be 0.05–0.2 mm. Everything else is the same as in Specific Implementation Methods One to Seven.

[0039] Specific Implementation Method Nine: This implementation method differs from Specific Implementation Methods One to Eight in that step four uses an MA80KV grinding wheel. Everything else is the same as in Specific Implementation Methods One to Eight.

[0040] Specific Implementation Method Ten: This implementation method differs from Specific Implementation Methods One to Nine in that the number of reciprocating motions of the workbench in step four is 130-170 times / minute. Everything else is the same as in Specific Implementation Methods One to Nine.

[0041] The scope of this invention is not limited to the above-described embodiments; a combination of one or more specific embodiments can also achieve the purpose of the invention.

[0042] Example:

[0043] A method for machining an extra-large ball loading notch on the outer ring of a thin-walled bearing, characterized by the following specific steps:

[0044] 1. Grind the outer raceway of the bearing workpiece.

[0045] 2. After the bearing workpiece is processed in step one, the notch is hard-milled in the machining center. The spiral interpolation milling method is used. The tool is a D16 carbide end mill with a cutting edge length of 25mm. First, the tool is brought to the machining starting point, then tilted at a 4° angle. The spiral interpolation milling program is used. The tool interpolates in the plane and walks out an arc with a radius of 12mm. At the same time, it slowly descends along the Z-axis to the machining end point, and then returns to the initial position.

[0046] Set the CNC machining program parameters: spindle forward rotation, speed 1000 r / min, feed 40 mm / min; tool returns to the program start point, 100 mm from the workpiece plane; tool rotates 4° around the Y-axis; coordinate system rotates 4° around the Y-axis; tool rapidly approaches the entry point, entry point coordinates X 38, Y 0, Z 3.2; tool rotates clockwise, performing 20 full circles in a helical pattern from the starting position, 0.45 mm per circle, milling to the Z-6X80 position, tool returns to the program start point, program ends;

[0047] Third, perform supplementary tempering on the bearing workpiece after step two, controlling the tempering temperature to 130℃.

[0048] Fourth, perform grinding notch treatment on the bearing workpiece after step three. Use an MA80KV grinding wheel, control the grinding wheel linear speed to be 20-25m / s, the transverse feed speed to be 2-3μm / s, the table reciprocating frequency to be 120-180 times / min, the grinding amount to be 0.05mm, and the locking ball height between the groove and the notch to be 0.05-0.2mm.

[0049] 5. Remove the notches and sharp angles from the bearing workpiece processed in step 4 to complete the process.

[0050] The thin-walled bearings processed using the method described in this embodiment reduce the amount of grinding involved in the machining process, improve the consistency of the locking point height dimensions, ensure that all dimensions and ovality of the outer ring are within acceptable limits, and meet the appearance quality requirements. The method also solves the problem of deformation caused by notches, achieving a product qualification rate of over 95%, and provides a reference for future processing of similar structures.

Claims

1. A method for machining an extra-large ball-filling notch on the outer ring of a thin-walled bearing, characterized in that... This method is specifically carried out in the following steps:

1. Grind the outer raceway of the bearing workpiece.

2. After the bearing workpiece is processed in step one, the notch is hard-milled using the helical interpolation milling method. The tool is a D16 carbide end mill. First, the tool is brought to the machining starting point, then tilted at a 4° angle. The helical interpolation milling program is used. The tool interpolates in the plane and moves out of an arc with a radius of 12mm. At the same time, it slowly descends along the Z-axis to the machining end point, and then returns to the initial position. Third, perform supplementary tempering on the bearing workpiece after step two, controlling the tempering temperature to be 125-135℃.

4. Grind the bearing workpiece after step 3 to make it notch, and control the grinding wheel linear speed to be 20-25m / s, the transverse feed speed to be 2-3μm / s, and the number of reciprocating cycles of the worktable to be 120-180 times / min.

5. Remove the notches and sharp angles from the bearing workpiece processed in step 4 to complete the process.

2. The method for machining the extra-large ball-filling notch on the outer ring of a thin-walled bearing according to claim 1, characterized in that... Step 2: Hard mill the notch at the machining center.

3. The method for machining the extra-large ball-filling notch on the outer ring of a thin-walled bearing according to claim 1, characterized in that... The cutting length of the tool mentioned in step two is 25mm.

4. The method for machining the extra-large ball-filling notch on the outer ring of a thin-walled bearing according to claim 1, characterized in that... Step 2: Set the CNC machining program parameters: Spindle forward rotation, speed 1000 r / min, feed 40 mm / min; Tool returns to the program start point, 100 mm from the workpiece plane; Tool rotates 4° around the Y-axis; Coordinate system rotates 4° around the Y-axis; Tool rapidly approaches the entry point, entry point coordinates X38, Y0, Z3.2; Tool rotates clockwise, performing 20 full circles in a spiral motion from the starting position, 0.45 mm per circle, milling to the Z-6X80 position; Tool returns to the program start point, program ends.

5. The method for machining the extra-large ball-filling notch on the outer ring of a thin-walled bearing according to claim 1, characterized in that... Step 3: Control the tempering temperature to 130℃.

6. The method for machining the extra-large ball-filling notch on the outer ring of a thin-walled bearing according to claim 1, characterized in that... Step four involves using a notching machine to grind the notch.

7. The method for machining the extra-large ball-filling notch on the outer ring of a thin-walled bearing according to claim 1, characterized in that... Step four: Control the grinding amount to 0.05mm.

8. The method for machining the extra-large ball-filling notch on the outer ring of a thin-walled bearing according to claim 1, characterized in that... Step four: Control the height of the locking ball between the channel and the notch to be 0.05–0.2 mm.

9. The method for machining the extra-large ball-filling notch on the outer ring of a thin-walled bearing according to claim 1, characterized in that... Step four uses an MA80KV grinding wheel.

10. The method for machining the extra-large ball-filling notch on the outer ring of a thin-walled bearing according to claim 1, characterized in that... Step four: The number of reciprocating motions of the workbench is 130-170 times per minute.

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