A method and fixture for polishing worm gear tooth surface using CNC lathe

Abstract

The present invention discloses a method and a fixture for polishing the tooth surface of a worm by using a numerically controlled lathe. The present invention is to clamp the worm on the tool holder of the numerically controlled lathe through the fixture, and then clamp the polishing wheel on the headstock of the numerically controlled lathe, and the numerically controlled lathe drives the polishing wheel to rotate; then the tool holder is controlled to translate the worm to contact the high-speed rotating polishing wheel, and the tooth surface of the worm is polished by the friction between the polishing wheel and the tooth surface of the worm. The present invention clamps worms with different parameters by replacing different axles to perform polishing operations; the operator does not need to fix the worm by hand, which can eliminate safety hazards; the numerically controlled lathe can control the polishing time and improve efficiency, and the polishing wheel drives the worm to rotate to ensure uniform polishing of the tooth surface, improve quality stability, and facilitate promotion.

Description

Technical Field

[0001] The invention relates to a method and a fixture for polishing a worm tooth surface by using a numerically controlled lathe, and belongs to the technical field of mechanical processing. Background Art

[0002] Noise has become an important indicator for evaluating worm gear transmission mechanisms. The roughness of the worm tooth surface is closely related to the transmission noise. Improving the tooth surface roughness can significantly reduce the noise of the worm gear transmission mechanism. Most of the existing worm tooth surface finishing uses a thread grinder, and the surface roughness of the machined worm is between Ra0.6-Ra0.8. In order to improve the tooth surface roughness, the method in the prior art is to hold the worm by hand and polish the tooth surface of the worm against the polishing wheel. After polishing, the tooth surface roughness is Ra0.2-Ra0.4. However, the method of the prior art has safety hazards, uneven tooth surface polishing, low efficiency, and relies on operator experience for processing, which is not conducive to promotion. Therefore, the prior art still has shortcomings and needs to be further improved. Summary of the invention

[0003] The purpose of the present invention is to provide a method and a fixture for polishing the tooth surface of a worm using a CNC lathe, so as to improve the efficiency of polishing the tooth surface of the worm, ensure uniform polishing of the tooth surface, improve product quality and facilitate promotion, thereby solving the shortcomings of the prior art.

[0004] To achieve the above object, the present invention adopts the following technical solution:

[0005] The present invention discloses a method for polishing a worm tooth surface by using a numerically controlled lathe. The method comprises the following steps: clamping the worm on a tool holder of the numerically controlled lathe through a fixture, and then clamping a polishing wheel on a headstock of the numerically controlled lathe, and the numerically controlled lathe drives the polishing wheel to rotate; then controlling the tool holder to translate the worm into contact with the high-speed rotating polishing wheel, and polishing the worm tooth surface through friction between the polishing wheel and the worm tooth surface.

[0006] In the above method, after the worm clamped on the tool holder of the CNC lathe contacts the polishing wheel, the worm rotates relative to the polishing wheel under the friction force of the polishing wheel. The linear speed of the worm rotation is less than the linear speed of the polishing wheel. There is a linear speed difference between the linear speed of the worm and the linear speed of the polishing wheel. The linear speed difference is determined by the friction force between the friction wheel at one end of the fixture and the belt.

[0007] In the above method, both ends of the belt are connected to the hanging plate by bolts, and the hanging plate is provided with an adjustment bolt. The pressure between the belt and the friction wheel is adjusted by the adjustment bolt. The pressure between the belt and the friction wheel is proportional to the linear speed difference.

[0008] A fixture for polishing the tooth surface of a worm gear using a CNC lathe of the present invention, which is constructed according to the above method and used for the above method, includes a base; a pair of bearing seats are fixed on the base; a deep groove ball bearing is installed in the bearing seat; the inner ring of the deep groove ball bearing is connected to the wheel axle; the wheel axle is connected to the friction wheel through a flat key; a tailstock is provided at one end of the base; a center is provided on the tailstock, and the processed worm gear is connected between the wheel axle and the center.

[0009] In the aforementioned clamp, a belt is sleeved on the friction wheel, and both ends of the belt are fixedly connected to a hanging plate located at the bottom of the base; an adjusting bolt is provided on the hanging plate.

[0010] In the aforementioned clamp, one end of the wheel shaft connected to the worm is provided with a convex key or a concave key; the convex key or the concave key is transmission-connected to the keyway or flat position at one end of the worm; the other end of the worm is provided with a center hole; the center hole is rotationally connected to the top.

[0011] Due to the adoption of the above technical scheme, compared with the prior art, the present invention performs polishing operations by replacing different axles to clamp worms with different parameters; the operator does not need to fix the worm by hand, which can eliminate safety hazards; the CNC lathe can control the polishing time and improve efficiency; the polishing wheel drives the worm to rotate, ensuring uniform polishing of the tooth surface, improving quality stability, and facilitating promotion. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a schematic diagram of the principle of the present invention when it is used;

[0013] Figure 2 It is a schematic structural diagram of the clamp of the present invention.

[0014] The markings in the accompanying drawings are: 1-base, 2-bearing seat, 3-deep groove ball bearing, 4-axle, 5-flat key, 6-friction wheel, 7-tail stock, 8-top, 9-belt, 10-hanging plate, 11-adjusting bolt, 12-worm, 13-convex key or concave key, 14-polishing wheel. DETAILED DESCRIPTION

[0015] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0016] A method for polishing a worm gear surface using a numerically controlled lathe according to the present invention, Figure 1As shown, the method is to clamp the worm 12 on the tool post of the CNC lathe through a fixture, and then clamp the polishing wheel 14 on the headstock of the CNC lathe, and the CNC lathe drives the polishing wheel 14 to rotate; then the tool post is controlled to translate the worm 12 to contact the high-speed rotating polishing wheel 14, and the tooth surface of the worm 12 is polished by the friction between the polishing wheel 14 and the tooth surface of the worm 12. After the worm 12 clamped on the tool post of the CNC lathe contacts with the polishing wheel 14, the worm 12 rotates relative to the polishing wheel 14 under the friction force of the polishing wheel 14, and the linear speed of the worm 12 is less than the linear speed of the polishing wheel 14, and there is a linear speed difference between the linear speed of the worm 12 and the linear speed of the polishing wheel 14; the linear speed difference is determined by the friction between the friction wheel 6 and the belt 9 provided at one end of the fixture. Both ends of the belt 9 are connected to the hanging plate 10 by bolts. The hanging plate 10 is provided with an adjusting bolt 11. The pressure between the belt 9 and the friction wheel 6 is adjusted by adjusting the bolt 11. The pressure between the belt 9 and the friction wheel 6 is proportional to the linear speed difference.

[0017] A fixture for polishing the tooth surface of a worm gear by using a numerically controlled lathe according to the above method and used in the above method, such as Figure 1 and Figure 2 As shown, the fixture includes a base 1; a pair of bearing seats 2 are fixed on the base 1; a deep groove ball bearing 3 is installed in the bearing seat 2; the inner ring of the deep groove ball bearing 3 is rotatably connected to the wheel shaft 4; the wheel shaft 4 is transmission-connected to the friction wheel 6 via a flat key 5; a tailstock 7 is provided at one end of the base 1; a top 8 is provided on the tailstock 7, and the processed worm 12 is connected between the wheel shaft 4 and the top 8. A belt 9 is sleeved on the friction wheel 6, and both ends of the belt 9 are fixedly connected to the hanging plate 10 located at the bottom of the base 4; an adjusting bolt 11 is provided on the hanging plate 10. A convex key or concave key 13 is provided at one end of the wheel shaft 4 connected to the worm 12; the convex key or concave key 13 is transmission-connected to the keyway or flat position at one end of the worm 12; a center hole is provided at the other end of the worm 12; the center hole is rotatably connected to the top 8.

[0018] The working process and principle of the present invention are further described below:

[0019] When polishing, Figure 1 As shown, the worm 12 is clamped on the fixture. When clamping, the keyway or flat position at one end of the worm 12 is connected to the convex key or concave key 13 at one end of the wheel shaft 4 on the fixture, and the top 8 on the fixture is pressed against the center hole at the other end of the worm 12. Then the base 1 of the fixture is clamped on the tool holder of the CNC lathe. In addition, the polishing wheel 14 is clamped on the headstock of the CNC lathe, and the CNC lathe drives the polishing wheel 14 to rotate and controls the speed of the polishing wheel 14. Then the tool holder is controlled so that the tooth surface of the worm 12 on the fixture is translated and contacts the outer edge of the polishing wheel 14. The worm 12 rotates together with the polishing wheel 14 under the friction force of the polishing wheel 14. The rotation direction of the worm 12 and the rotation direction of the polishing wheel 14 are as shown in Figure 1The rotation direction is opposite. Since one end of the worm 12 is connected to the friction wheel 6 through the axle 4, the friction wheel 6 rotates simultaneously when the worm 12 rotates. A belt 9 is provided on the friction wheel 6, and the belt 9 is wrapped on the arc of the upper half of the friction wheel 6. Both ends of the belt 9 are connected to the hanging plate 10 located at the bottom of the base 1, and the arc at the top of the belt 9 is slidably connected with the friction wheel 6. An adjusting bolt 11 is provided on the hanging plate 10, and the adjusting bolt 11 passes through the threaded hole on the hanging plate 10 and is pressed against the bottom of the base 1. When the adjusting bolt 11 is adjusted, the pressure of the belt 9 on the friction wheel 6 can be adjusted. The belt 9 has a braking function to limit the rotation of the friction wheel 6. The linear velocity of the rotation of the worm 12 lags behind the linear velocity of the rotation of the polishing wheel 14, so there is sliding friction between the worm 12 and the polishing wheel 14; the polishing of the tooth surface of the worm 12 is completed by the sliding friction between the worm 12 and the polishing wheel 14.

[0020] When the adjusting bolt 11 is not in contact with the bottom of the base 1, the friction between the worm 12 and the polishing wheel 14 is minimal, and the linear velocity of the worm 12 lags behind the linear velocity of the polishing wheel 14. When the adjusting bolt 11 is pressed against the bottom of the base 1, the belt 9 is tightened downward by the hanging plate 10, and the pressure between the belt 9 and the friction wheel 6 gradually increases, and the linear velocity difference between the worm 12 and the polishing wheel 14 also increases accordingly, and the polishing speed is the fastest at this time. The polishing pressure between the worm 12 and the polishing wheel 14 is determined by the pressure of the worm 12 against the polishing wheel 14, that is, the feed amount of the tool holder.

[0021] After polishing is completed, the tool holder is moved outward to make the worm 12 leave the polishing wheel 14, the friction wheel 6 stops rotating under the braking force of the belt, and the polished worm 12 is removed from the fixture. Repeat the above process to polish the next worm 12.

[0022] The present invention performs polishing operations by replacing different wheel axles to clamp worms with different parameters; the operator does not need to fix the worm by hand, which can eliminate potential safety hazards; the CNC lathe can control the polishing time and improve efficiency; the polishing wheel drives the worm to rotate, ensuring uniform polishing of the tooth surface, improving quality stability, and facilitating promotion.

Claims

1. A method for polishing a worm gear tooth surface using a CNC lathe, characterized in that: The method is to clamp the worm on the tool holder of a numerically controlled lathe through a fixture, and then clamp the polishing wheel on the headstock of the numerically controlled lathe, and the numerically controlled lathe drives the polishing wheel to rotate; then the tool holder is controlled to translate the worm into contact with the high-speed rotating polishing wheel, and the tooth surface of the worm is polished by the friction between the polishing wheel and the tooth surface of the worm; after the worm clamped on the tool holder of the numerically controlled lathe contacts with the polishing wheel, the worm rotates relative to the polishing wheel under the friction force of the polishing wheel, the linear speed of the worm rotation is less than the linear speed of the polishing wheel rotation, and there is a linear speed difference between the linear speed of the worm and the linear speed of the polishing wheel; the linear speed difference is determined by the friction force between the friction wheel and the belt provided at one end of the fixture; the two ends of the belt are connected to a hanging plate through bolts, and the hanging plate is provided with an adjusting bolt, and the pressure between the belt and the friction wheel is adjusted by the adjusting bolt, and the pressure between the belt and the friction wheel is proportional to the linear speed difference; the fixture comprises a base (1); A pair of bearing seats (2) are fixed on the base (1); a deep groove ball bearing (3) is installed in the bearing seat (2); the inner ring of the deep groove ball bearing (3) is connected to the wheel shaft (4); the wheel shaft (4) is connected to the friction wheel (6) through a flat key (5); a tailstock (7) is provided at one end of the base (1); a top (8) is provided on the tailstock (7); a processed worm (12) is connected between the wheel shaft (4) and the top (8); a belt (9) is sleeved on the friction wheel (6); both ends of the belt (9) are fixedly connected to a hanging plate (10) located at the bottom of the base (1); an adjusting bolt (11) is provided on the hanging plate (10); a convex key or a concave key (13) is provided at one end of the wheel shaft (4) connected to the worm (12); the convex key or the concave key (13) is connected to the keyway or flat position at one end of the worm (12); a center hole is provided at the other end of the worm (12); the center hole is connected to the top (8) in rotation.

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