Gear tooth surface machining device and gear tooth surface machining method

Abstract

This invention provides a tooth surface machining apparatus and a tooth surface machining method. The tooth surface machining apparatus (10) includes a first motor (16), a predetermined sensor (18), a second motor (22), and a control device (26). The first motor (16) rotates a grinding tool (12) having tool teeth (28) having a tooth thickness (W28) smaller than the width (W102) of the tooth groove (102) of the gear (100) to be machined. The predetermined sensor (18) outputs a detection signal corresponding to the load of the first motor. The second motor (22) rotates the gear to be machined. The control device (26) controls the second motor according to the detection signal to adjust the lead angle of the gear to be machined so that the load when grinding the tooth surface (104) forming the tooth groove through the tool teeth is kept within a predetermined allowable range. Accordingly, better machining accuracy can be achieved.

Description

Technical Field

[0001] This invention relates to a tooth surface machining apparatus and a tooth surface machining method. Background Technology

[0002] Japanese Patent Publication No. 6030857 discloses a technology relating to a tooth surface machining apparatus. According to Japanese Patent Publication No. 6030857, the tooth surface machining apparatus uses a helical toothed abrasive stone (spiral gear abrasive) to finish the tooth surface of a high-hardness gear. Summary of the Invention

[0003] Recently, there has been a desire for more advanced technology in gear surface machining devices equipped with helical tooth grinding stones for grinding gears.

[0004] The purpose of this invention is to solve the above-mentioned technical problems.

[0005] A first aspect of the present invention is a tooth surface machining apparatus for grinding the tooth surface of a tooth groove forming a gear to be machined. The apparatus includes a first motor, a predetermined sensor, a second motor, and a control device. The first motor rotates a grinding tool having tool teeth with a tooth thickness smaller than the width of the tooth groove. The predetermined sensor outputs a detection signal corresponding to the load of the first motor. The second motor rotates the gear to be machined. The control device controls the second motor based on the detection signal, adjusting the lead angle of the gear to be machined relative to the grinding tool, so that the load during grinding of the tooth surface by the rotating tool teeth remains within a predetermined allowable range.

[0006] The second aspect of the present invention is a tooth surface machining method for grinding the tooth surface of a gear forming a tooth groove using a tooth surface machining device. The tooth surface machining device includes a first motor, a predetermined sensor, a second motor, and a control device. The first motor rotates a grinding tool having tool teeth with a tooth thickness smaller than the width of the tooth groove. The predetermined sensor outputs a detection signal corresponding to the load of the first motor. The second motor rotates the gear to be machined. The control device controls the second motor. The tooth surface machining method includes a signal acquisition step and a lead angle adjustment step. In the signal acquisition step, the control device acquires the detection signal. In the lead angle adjustment step, the second motor is controlled according to the detection signal to adjust the lead angle of the gear to be machined relative to the grinding tool, so that the load when grinding the tooth surface by the rotating tool teeth of the grinding tool is kept within a predetermined allowable range.

[0007] According to the present invention, better tooth surface machining apparatus and tooth surface machining methods can be provided.

[0008] The above-described objectives, features, and advantages should be readily understood through the description of the following embodiments with reference to the accompanying drawings. Attached Figure Description

[0009] Figure 1 This is a structural diagram of a tooth surface machining apparatus according to one embodiment.

[0010] Figure 2 yes Figure 1 A magnified view of a portion of the frame.

[0011] Figure 3 This is a flowchart of a tooth surface machining method according to one embodiment. Detailed Implementation

[0012] There is a desired technique for achieving stable finishing, which can machine the surface roughness of the tooth surface with higher precision and less fluctuation while maintaining the tooth shape formed in the previous process. The load applied to the tooth surface during machining has a significant impact on both machining accuracy and surface roughness fluctuations. Therefore, it is desirable to stably maintain this load. Furthermore, according to Japanese Patent Publication No. 6030857, the lead angle of the machined gear relative to the helical grinding stone is controlled based on the rotational torque of the gear's rotating shaft. However, intermediate components such as a torsion buffer, position encoder, and timing belt are provided between this rotating shaft and the drive servo motor that drives the rotating shaft. The presence of these intermediate components may degrade the accuracy of the rotational torque detection. This degraded accuracy of the rotational torque detection adversely affects the machining accuracy of the gear.

[0013] Based on the above preparatory explanation, an implementation method will be described below. Furthermore, the program (computer program, computer software) mentioned in the following description is also referred to as a computer program product. A computer program product is not limited to programs stored on storage media, but also includes programs transmitted, distributed, and downloaded via networks such as the Internet.

[0014] (One implementation method) Figure 1 This is a structural diagram of a tooth surface machining apparatus 10 according to one embodiment. Figure 2 yes Figure 1 A magnified view of a portion of the frame. Figure 2 express Figure 1 Enlarged view of frame II.

[0015] The tooth surface machining device 10 is a machining device for grinding the tooth surface 104 of the gear 100 to be machined. For example... Figure 1As shown, the tooth surface machining apparatus 10 includes a grinding tool 12, a first shaft 14, a first motor 16, a specified sensor 18, a second shaft 20, a second motor 22, one or more intermediate components 24, and a control device 26.

[0016] The gear to be machined 100 is a workpiece that has been ground by the tooth surface machining device 10. For example, spur gears, helical gears, and other gears are included in the gear to be machined 100. Figure 2 As shown, the gear 100 to be processed has a plurality of teeth 106 to be processed. Each of the plurality of teeth 106 is formed by pre-machining the substrate of the gear 100. Tooth grooves 102 (a plurality of tooth grooves 102) are formed between the plurality of teeth 106 to be processed. Tooth surfaces 104 are the surfaces of the teeth 106 to be processed that form the tooth grooves 102. In the following description, the tooth surface 104 of one of the two teeth 106 to be processed that form the same tooth groove 102 is also referred to as the first tooth surface 104a, and the tooth surface 104 of the other is also referred to as the second tooth surface 104b.

[0017] The grinding tool 12 is, for example, a grinding stone. The grinding tool 12 has tool teeth 28. Tool teeth 28 are teeth that abut against the tooth surface 104 of the gear 100 to be ground. The tool teeth 28 (grinding tool 12) are preferably formed of an elastic material that can deform along the shape of the tooth surface 104 of the gear 100 to be ground. Accordingly, the risks of grinding burns, cracks, and breakage of the grinding tool 12 in the gear 100 to be ground can be reduced. The tool teeth 28 have a worm shape (see also...). Figure 1 However, it is not limited to this. For example, the tool teeth 28 may also have a helical tooth shape. A grinding tool 12 with a tool teeth 28 of the desired shape can be suitably provided in the tooth surface machining apparatus 10.

[0018] The tooth thickness W28 of the tool tooth 28 is less than the width W102 of the tooth groove 102 (W28 < W102). Therefore, when one of the first tooth surface 104a and the second tooth surface 104b abuts against the tool tooth 28, the other of the first tooth surface 104a and the second tooth surface 104b does not abut against the tool tooth 28 (see also...). Figure 2 ).

[0019] The first shaft portion 14 is the shaft portion that supports the grinding tool 12. The first shaft portion 14 is connected to the first shaft body 30 of the first motor 16 described below (see also...). Figure 1 ), and rotate together with the first axis 30.

[0020] The first motor 16 is an electric motor that rotates the grinding tool 12. The first motor 16 is, for example, a spindle motor. The first motor 16 has a first shaft 30 and a first encoder 32.

[0021] The first shaft 30 is a rotatable shaft. By rotating the first shaft 30, the grinding tool 12 rotates together with the first shaft portion 14.

[0022] The first encoder 32 is a rotary encoder that outputs a detection signal corresponding to the rotational position of the first shaft 30. In the following description, this detection signal is also referred to as the first rotational position signal SR1.

[0023] Furthermore, preferably, the grinding tool 12 is directly connected to the first shaft portion 14, and the first shaft portion 14 is directly connected to the first shaft body 30. Accordingly, the first backlash is suppressed. The first backlash is the gap between the grinding tool 12 and the first motor 16 (amount of backlash). By suppressing the increase of the first backlash, the first backlash is easily set to be smaller than the second backlash. The second backlash is the gap between the gear 100 to be processed and the second motor 22 (described later) (amount of backlash).

[0024] The specified sensor 18 is a sensor that outputs a detection signal corresponding to the load of the first motor 16. In the following description, this detection signal is also referred to as the load signal SL. The load of the first motor 16 is, for example, the rotational torque of the first shaft 30. The greater the clamping force applied by the tool teeth 28 of the grinding tool 12 rotating through the first motor 16 to the tooth surface 104 of the gear 100 to be processed, the greater the load on the first motor 16. In other words, the greater the friction between the tool teeth 28 and the tooth surface 104, the greater the load on the first motor 16.

[0025] The specified sensor 18 is, for example, a torque meter, but is not limited to this. The specified sensor 18 can also be a sensor for detecting a physical quantity that has a causal relationship with the change in the rotational torque of the first shaft 30 (see also the modified example 2 described later). For example, the first motor 16 rotates the grinding tool 12 pressed against the tooth surface 104 of the gear 100 to be processed. In this case, a causal relationship can be found between the change in the rotational torque of the first shaft 30 and the changes in the current flowing through the first motor 16, the voltage applied to the first motor 16, etc. Based on this causal relationship, it can be understood that the signals representing the current and the voltage are signals corresponding to the load of the first motor 16. Therefore, the specified sensor 18 can also be, for example, a current sensor that detects the current flowing through the first motor 16, a voltage sensor that detects the voltage applied to the first motor 16, etc.

[0026] The second shaft 20 is a shaft that supports the gear 100 to be processed. The second motor 22 is an electric motor that rotates the gear 100 to be processed by rotating the second shaft 20. The second motor 22 is, for example, a spindle motor. The second motor 22 has a second shaft 34 and a second encoder 36.

[0027] The second shaft 34 is a rotatable shaft. In response to the rotation of the second shaft 34, the second shaft portion 20 and the gear 100 to be processed rotate.

[0028] The second encoder 36 is a rotary encoder that outputs a detection signal corresponding to the rotational position of the second shaft 34. In the following description, this detection signal is also referred to as the second rotational position signal SR2.

[0029] Associated with the first shaft portion 14 and the second shaft portion 20 described above, in Figure 1 The diagram also shows a first rotation axis LA1 and a second rotation axis LA2. The first rotation axis LA1 is the rotation axis of the grinding tool 12 (first shaft portion 14). The second rotation axis LA2 is the rotation axis of the gear 100 to be processed (second shaft portion 20). The first rotation axis LA1 and the second rotation axis LA2 may intersect.

[0030] One or more connecting components 24 are components (component groups) located between the second motor 22 and the second shaft 20. For example, the connecting component 24 is a speed reducer 24a disposed between the second motor 22 and the gear 100 to be processed. The speed reducer 24a reduces the rotational speed of the second shaft 34 before transmitting the speed to the gear 100 to be processed. The speed reducer 24a may also be disposed within the second motor 22. Synchronous belts, pulleys, etc., may also be disposed as connecting components 24 between the second motor 22 and the second shaft 20, but are not shown in the figures.

[0031] The control device 26 is an electronic device (computer) that controls the first motor 16 and the second motor 22, thereby controlling the grinding process of the grinding tool 12 on the tooth surface 104. The control device 26 has a storage unit 38 and a calculation unit 40.

[0032] Storage unit 38 includes one or more memory units. Storage unit 38 may include, for example, non-volatile memory such as ROM (Read Only Memory), flash memory, or hard disk. Non-volatile memory is a storage medium used for non-temporary storage of programs, tables, mapping tables, etc. At least a portion of storage unit 38 may also be implemented using portable storage media such as USB (Universal Serial Bus) memory, memory cards, or optical discs. Storage unit 38 may also include volatile memory such as RAM (Random Access Memory).

[0033] The arithmetic unit 40 includes a processing circuitry capable of performing arithmetic operations. This processing circuitry may have one or more processors. For example, the processing circuitry may also have a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), etc. The processing circuitry may have an integrated circuit (IC) or discrete components.

[0034] The arithmetic unit 40 includes a signal acquisition unit 42, a first motor control unit 44, and a second motor control unit 46. The signal acquisition unit 42, the first motor control unit 44, and the second motor control unit 46 are implemented using the processing circuit described above. For example, the signal acquisition unit 42, the first motor control unit 44, and the second motor control unit 46 are implemented by the processor of the arithmetic unit 40 executing a program stored in the storage unit 38. At least a portion of the signal acquisition unit 42, the first motor control unit 44, and the second motor control unit 46 can also be implemented using at least one of the IC and discrete devices described above.

[0035] The signal acquisition unit 42 acquires the first rotational position signal SR1, the second rotational position signal SR2, and the load signal SL.

[0036] The first motor control unit 44 controls the first motor 16 to rotate the grinding tool 12. The first motor control unit 44 can also control the first motor 16 to bring the rotational speed of the grinding tool 12 to a predetermined target speed. In this case, the first motor control unit 44 can also perform feedback control on the first motor 16 based on the first rotational position signal SR1 acquired by the signal acquisition unit 42. Accordingly, the rotational speed of the grinding tool 12 is gradually adjusted to the target speed.

[0037] The second motor control unit 46 adjusts the lead angle of the gear 100 to be processed relative to the grinding tool 12 by controlling the second motor 22 according to the load signal SL and the second rotational position signal SR2. The lead angle of the gear 100 to be processed relative to the grinding tool 12 is the rotational phase difference between the gear 100 (tooth surface 104) and the grinding tool 12. For example, the phase difference between a certain rotational position (reference position) of the grinding tool 12 and the gear 100 to be processed can be determined as the lead angle.

[0038] As described above, the greater the clamping force of the tool teeth 28 on the tooth surface 104, the greater the load on the first motor 16. Based on this, the second motor control unit 46 performs feedback control on the second motor 22 according to the second rotational position signal SR2, so as to keep the load on the first motor 16, as indicated by, for example, the load signal SL, within an allowable range. Accordingly, the load on the first motor 16 is kept within an allowable range. The allowable range is predetermined based on experiments, simulations, etc.

[0039] More specifically, when the load on the first motor 16 exceeds the allowable range, the second motor control unit 46 adjusts the lead angle in a direction that moves the tooth surface 104 being ground by the tool teeth 28 away from the tool teeth 28. On the other hand, when the load on the first motor 16 is less than the allowable range, the second motor control unit 46 adjusts the lead angle in a direction that moves the tooth surface 104 being ground by the tool teeth 28 closer to the tool teeth 28.

[0040] For example in Figure 2 In the example, the first tooth surface 104a is forward ground by the tool teeth 28. In this example, when the load on the first motor 16 exceeds the allowable range, the second motor control unit 46 adjusts the aforementioned lead angle in the direction of arrow A, which moves the first tooth surface 104a away from the tool teeth 28. Accordingly, the load on the first motor 16 is reduced and kept within the allowable range. On the other hand, in Figure 2 In the example, when the load on the first motor 16 is less than the allowable range, the second motor control unit 46 adjusts the lead angle as described above in the direction of arrow B, which brings the first tooth surface 104a closer to the tool tooth 28. Accordingly, the load on the first motor 16 increases but remains within the allowable range.

[0041] Figure 3 This is a flowchart illustrating a tooth surface machining method according to one embodiment.

[0042] The tooth surface machining device 10 (control device 26) is capable of performing Figure 3 The tooth surface machining method shown includes a signal acquisition step S1 and a lead angle adjustment step S2. During the execution of this tooth surface machining method, the first motor 16 is controlled by the control device 26 (first motor control unit 44), but the details are omitted. Figure 3 The illustration.

[0043] In the signal acquisition step S1, the control device 26 (signal acquisition unit 42) acquires the load signal SL.

[0044] In the lead angle adjustment step S2, the control device 26 (second motor control unit 46) controls the second motor 22 according to the load signal SL. Accordingly, the lead angle of the gear 100 to be processed relative to the grinding tool 12 is adjusted in such a way that the load of the first motor 16 is kept within the allowable range.

[0045] The tooth surface machining device 10 described above performs the functions and effects described below.

[0046] For example, for purposes such as increasing rotational torque, the gear 100 to be processed and the second motor 22 are often separated by one or more interfacing components 24, including a reducer 24a. Therefore, the second clearance tends to be larger than the first clearance. The larger the second clearance, the worse the efficiency of force transmission from the tooth surface 104 to the second motor 22. For this reason, the load (torque) of the second motor 22 is difficult to reflect the frictional force generated by the large clamping force of the tool teeth 28 on the tooth surface 104. Therefore, it is difficult to accurately determine whether the contact between the tooth surface 104 and the tool teeth 28 during grinding is appropriate by observing the load of the second motor 22. In contrast, for example, for purposes such as enabling the grinding tool 12 to rotate at a relatively high speed, the grinding tool 12 (first shaft 14) and the first shaft 30 are configured to rotate integrally. As a result, in most cases, the first clearance is set relatively small, and is smaller than the second clearance. For this reason, the transmission efficiency of force from the tool teeth 28 to the first motor 16 is better than the transmission efficiency of force from the tooth surface 104 to the second motor 22. That is, the load on the first motor 16 easily reflects the frictional force (torque applied to the tooth surface 104) generated by the large clamping force of the tool teeth 28 on the tooth surface 104. Based on the above, according to this embodiment, the control device 26 can adjust the lead angle of the gear 100 to be processed relative to the grinding tool 12 by controlling the second motor 22 according to the load of the first motor 16. Accordingly, the tooth surface processing apparatus 10 can appropriately adjust the contact between the tooth surface 104 and the tool teeth 28 during grinding. Therefore, the tooth surface processing apparatus 10 can achieve good processing accuracy.

[0047] The control device 26 controls the first motor 16 to make the rotational speed of the grinding tool 12 reach a predetermined target speed. By continuously maintaining the rotational speed of the grinding tool 12 at a certain degree, the control device 26 can achieve good machining accuracy.

[0048] One embodiment can also be modified as described below. In the following description, descriptions that are repeated with one embodiment are suitably omitted. Furthermore, the reference numerals used to denote structural elements in one embodiment are also used in the following description.

[0049] (Variation Example 1) The first shaft 30 of the first motor 16 can also serve as the first shaft portion 14 supporting the grinding tool 12. That is, the first shaft portion 14 can also be the first shaft 30. In this case, the grinding tool 12 is directly connected to the first shaft 30. In this way, the friction between the grinding tool 12 (tool teeth 28) and the gear 100 (tooth surface 104) to be processed can be easily reflected under the load of the first motor 16. Accordingly, the control device 26 can better adjust the lead angle of the gear 100 to be processed relative to the grinding tool 12 according to the load of the first motor 16.

[0050] (Variation Example 2) The rotational torque of the first shaft 30 can be estimated based on the rotational speed, rotational acceleration, etc. of the first shaft 30. Based on this, the first encoder 32 can also function as the designated sensor 18. That is, the designated sensor 18 can also be the first encoder 32. In this case, the control device 26 (first motor control unit 44) also uses the first rotational position signal SR1, which is used for feedback control of the first motor 16, as the load signal SL. More specifically, the first motor control unit 44 estimates the rotational torque of the first shaft 30 based on the first rotational position signal SR1 and determines this rotational torque as the load of the first motor 16.

[0051] In most cases, motors such as spindle motors are already equipped with rotary encoders. Therefore, according to this modification, it is not necessary to add torque meters, current sensors, voltage sensors, etc. (refer to one embodiment) as standard sensors 18. Therefore, the manufacturing cost and component procurement cost of the tooth surface machining apparatus 10 can be reduced. In addition, since it is not necessary to configure torque meters, current sensors, voltage sensors, etc. as standard sensors 18, the flexibility in the arrangement of various components in the tooth surface machining apparatus 10 can be ensured.

[0052] The following notes are also disclosed regarding the above-described embodiments.

[0053] (Note 1) The tooth surface processing apparatus (10) of the present invention is used to grind the tooth surface (104) of the tooth groove (102) forming the gear (100) to be processed. It has a first motor (16), specified sensors (18, 32), a second motor (22) and a control device (26). The first motor (16) is used to rotate a grinding tool (12) provided with tool teeth (28), the tool teeth (28) having a tooth thickness (W28) smaller than the width (W102) of the tooth groove. The specified sensors (18, 32) are used to output a detection signal corresponding to the load of the first motor. The second motor (22) is used to rotate the gear to be processed. The control device (26) controls the second motor according to the detection signal and adjusts the lead angle of the gear to be processed relative to the grinding tool so that the load when grinding the tooth surface by the tool teeth of the rotating grinding tool is kept within a predetermined allowable range. Therefore, the tooth surface machining device can achieve good machining accuracy.

[0054] (Note 2) In the tooth surface machining apparatus described in Appendix 1, the control device may also control the first motor to make the rotational speed of the grinding tool reach a predetermined target speed. Accordingly, the tooth surface machining apparatus can achieve better machining accuracy.

[0055] (Note 3) In the tooth surface machining apparatus described in Appendix 1 or 2, the grinding tool may also be directly connected to the shaft (30) of the first motor. Accordingly, the tooth surface machining apparatus can achieve better machining accuracy.

[0056] (Note 4) In the gear surface machining apparatus described in Appendix 1 or 2, a speed reducer (24a) may also be provided, which is disposed between the second motor and the gear to be machined. Accordingly, the torque of the gear to be machined can be increased.

[0057] (Note 5) In the tooth surface machining apparatus described in Appendix 1 or 2, the gap between the grinding tool and the first motor (i.e., the first gap) may be smaller than the gap between the gear to be machined and the second motor (i.e., the second gap). Accordingly, the tooth surface machining apparatus can achieve better machining accuracy.

[0058] (Note 6) The tooth surface machining method of the present invention is used to grind the tooth surface (104) of the tooth groove (102) forming the gear (100) to be machined by means of a tooth surface machining device (10). The tooth surface machining device has a first motor (16), specified sensors (18, 32), a second motor (22) and a control device (26). The first motor (16) is used to rotate a grinding tool (12) provided with tool teeth (28), the tool teeth (28) having a tooth thickness (W28) smaller than the width (W102) of the tooth groove. The specified sensors (18, 32) are used to output the load of the first motor. The detection signal is obtained; the second motor (22) is used to rotate the gear to be processed; the control device (26) is used to control the second motor. The tooth surface processing method includes a signal acquisition step (S1) and a lead angle adjustment step (S2). In the signal acquisition step (S1), the control device acquires the detection signal; in the lead angle adjustment step (S2), the second motor is controlled according to the detection signal to adjust the lead angle of the gear to be processed relative to the grinding tool so that the load when grinding the tooth surface by the tool teeth of the rotating grinding tool is kept within a predetermined allowable range.

[0059] The present invention has been described in detail, but it is not limited to the various embodiments described above. Various additions, substitutions, modifications, and partial deletions can be made to these embodiments without departing from the spirit of the invention or the spirit of the invention derived from the content described in the technical solutions and their equivalents. Furthermore, these embodiments can also be implemented in combination. For example, in the embodiments described above, the order of each action and the order of each process are shown as an example, but are not limited thereto. The same applies to the use of numerical values ​​or mathematical formulas in the description of the embodiments described above.

Claims

1. A tooth surface machining apparatus for grinding the tooth surface of a gear forming a tooth groove, characterized in that, It has a first motor, a specified sensor, a second motor, and a control device, wherein, The first motor is used to rotate a grinding tool having tool teeth, the tool teeth having a tooth thickness smaller than the width of the tooth groove; The specified sensor is used to output a detection signal corresponding to the load of the first motor; The second motor is used to rotate the gear to be processed; The control device controls the second motor according to the detection signal, and adjusts the lead angle of the gear to be processed relative to the grinding tool, so that the load when grinding the tooth surface by the tool teeth of the rotating grinding tool is kept within a predetermined allowable range.

2. The tooth surface machining apparatus according to claim 1, characterized in that, The control device controls the first motor to make the grinding tool rotate at a predetermined target speed.

3. The tooth surface machining apparatus according to claim 1 or 2, characterized in that, The grinding tool is directly connected to the shaft of the first motor.

4. The tooth surface machining apparatus according to claim 1 or 2, characterized in that, It also includes a speed reducer, which is configured between the second motor and the gear to be processed.

5. The tooth surface machining apparatus according to claim 1 or 2, characterized in that, The gap between the grinding tool and the first motor, i.e., the first gap, is smaller than the gap between the gear to be processed and the second motor, i.e., the second gap.

6. A tooth surface machining method, used to grind the tooth surface of the tooth groove forming the gear to be machined by means of a tooth surface machining device, characterized in that, The tooth surface machining device includes a first motor, a specified sensor, a second motor, and a control device, wherein... The first motor is used to rotate a grinding tool having tool teeth, the tool teeth having a tooth thickness smaller than the width of the tooth groove; The specified sensor is used to output a detection signal corresponding to the load of the first motor; The second motor is used to rotate the gear to be processed; The control device is used to control the second motor. The tooth surface machining method includes a signal acquisition step and a lead angle adjustment step. In the signal acquisition step, the control device acquires the detection signal; In the lead angle adjustment step, the second motor is controlled according to the detection signal to adjust the lead angle of the gear to be processed relative to the grinding tool, so that the load when grinding the tooth surface by the tool teeth of the rotating grinding tool is kept within a predetermined allowable range.

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