Workpiece grinding method and grinding system

Abstract

To provide a grinding method of a work-piece which accurately grinds a tooth surface of the work-piece that has heat strain due to heat treatment.SOLUTION: A grinding method of a work-piece 12 comprises: a first grinding step where a toothed wheel-like work-piece and a grinding tool 14 are engaged and rotated so that a grinding tooth flank 66 grinds the work-piece tooth surface 62; a first correction information generation step which generates first correction information through inverting a first vibration waveform; and a second grinding step where rotational speed of the work-piece or the grinding tool is changed, while the work-piece and the grinding tool are engaged and rotated, on the basis of the first correction information to grind the work-piece tooth surface through the grinding tooth flank.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a method and system for grinding a workpiece. [Background technology]

[0002] Patent Document 1 discloses a method for grinding a workpiece in which a gear-shaped workpiece and a grinding tool are meshed and rotated, so that the tooth surface of the workpiece is ground by the spiral grinding tooth surface of the grinding tool. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 5467833 Summary of the Invention [Problem to be solved by the invention]

[0004] There is a need for a better method and system for grinding a workpiece.

[0005] The present disclosure aims to solve the above-mentioned problems. [Means for solving the problem]

[0006] A first aspect of the present disclosure is a method for grinding a workpiece, comprising: a first grinding step in which a gear-shaped workpiece is rotated in mesh with a grinding tool to grind the workpiece tooth surface with the spiral grinding tooth surface of the grinding tool; a first correction information generation step in which first correction information is generated by inverting a first runout waveform that indicates the relationship between the amount of runout of the workpiece tooth surface relative to the grinding tooth surface during the first grinding step and the rotational phase of the workpiece; and a second grinding step in which, while the workpiece is rotated in mesh with the grinding tool, the rotational speed of the workpiece or the grinding tool is changed based on the first correction information to grind the workpiece tooth surface with the grinding tooth surface.

[0007] A second aspect of the present disclosure is a grinding system comprising: a grinding control unit that performs a first grinding step in which a gear-shaped workpiece is rotated in mesh with a grinding tool to grind the workpiece tooth surface with the spiral grinding tooth surface of the grinding tool; and a correction information generation unit that generates first correction information by inverting a first runout waveform that indicates the relationship between the amount of runout of the workpiece tooth surface relative to the grinding tooth surface during the first grinding step and the rotational phase of the workpiece, wherein the grinding control unit further performs a second grinding step in which the workpiece tooth surface is ground with the grinding tooth surface by changing the rotational speed of the workpiece or the grinding tool based on the first correction information while the workpiece is rotated in mesh with the grinding tool. [Effects of the Invention]

[0008] According to the present disclosure, a better workpiece grinding method and grinding system can be provided. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a perspective view of a grinding system according to an embodiment. [Figure 2] FIG. 2 is a control block diagram of the grinding system. [Figure 3] FIG. 3 is a flowchart showing an example of a method for grinding a workpiece. [Figure 4] FIG. 4 is an explanatory diagram of the first correction information generating step. [Figure 5] FIG. 5 is an explanatory diagram of the second correction information generating step. [Figure 6] FIG. 6 is a graph showing a runout waveform in the third grinding step. DETAILED DESCRIPTION OF THE INVENTION

[0010] A gear-shaped workpiece is subjected to heat treatment before grinding. In this case, the workpiece may be deformed into an elliptical shape due to thermal distortion when viewed from the direction of the workpiece's rotation axis. This may result in the workpiece tooth surface not being accurately ground by the grinding tooth surface. The present disclosure can provide a workpiece grinding method and grinding system that can accurately grind the workpiece tooth surface.

[0011] Fig. 1 is a perspective view of a grinding system 10 according to an embodiment. As shown in Fig. 1, the grinding system 10 is a system for grinding a gear-shaped workpiece 12 using a grinding tool 14. The grinding system 10 includes a bed 16, a gear support mechanism 18, a gear rotation mechanism 20, a tool support mechanism 22, a tool rotation mechanism 24, and a control device 26.

[0012] The bed 16 is placed on a horizontal surface, for example, in a factory. The gear support mechanism 18 is disposed on the flat upper surface of the bed 16. The gear support mechanism 18 has a cutting table 28, a cutting motor 30, a traverse table 32, and a traverse motor 34.

[0013] The cutting table 28 moves in the direction A relative to the bed 16. The direction A is a horizontal direction perpendicular to the height direction of the bed 16. The cutting table 28 is connected to a cutting motor 30 via a ball screw shaft 36. The cutting motor 30 moves the cutting table 28 in the direction A by rotating the ball screw shaft 36.

[0014] The traverse table 32 is disposed on the upper surface of the cutting table 28. The traverse table 32 moves in the direction B relative to the cutting table 28. The direction B is perpendicular to the height direction of the bed 16 and the direction A. The traverse table 32 is connected to a traverse motor 34 via a ball screw shaft (not shown). The traverse motor 34 moves the traverse table 32 in the direction B by rotating the ball screw shaft.

[0015] The gear rotation mechanism 20 is disposed on the upper surface of the traverse table 32. The gear rotation mechanism 20 has a gear mounting shaft 38 and a first motor 40. The gear mounting shaft 38 extends in the direction B. The workpiece 12 is detachably attached to the gear mounting shaft 38. The first motor 40 rotates the gear mounting shaft 38.

[0016] The tool support mechanism 22 has a column 42, a swivel table 44, a shift table 46, and a shift motor 48. The column 42 is disposed on the upper surface of the bed 16 so as to face the gear support mechanism 18. The column 42 extends upward from the bed 16. The swivel table 44 is attached to the surface of the column 42 facing the gear support mechanism 18.

[0017] The swivel table 44 extends in one direction. A swivel motor (not shown) swivels the swivel table 44 in direction C relative to the column 42. A shift table 46 is provided on the surface of the swivel table 44 facing the gear support mechanism 18. The shift table 46 is connected to a shift motor 48 via a ball screw shaft 50. The shift motor 48 is attached to the swivel table 44. The shift motor 48 moves the shift table 46 in direction D relative to the swivel table 44.

[0018] The tool rotation mechanism 24 has a base portion 54, a tool mounting shaft 56, and a second motor 58. The base portion 54 is attached to the surface of the shift table 46 that faces the gear support mechanism 18. The base portion 54 extends in the extension direction of the swivel table 44. The tool mounting shaft 56 is inserted through the base portion 54 in the extension direction of the base portion 54. The grinding tool 14 is detachably attached to the tool mounting shaft 56. The second motor 58 rotates the tool mounting shaft 56.

[0019] As shown in Figure 2, the workpiece 12 is attached to the gear mounting shaft 38. The workpiece 12 can be rotated in the R1 direction and the R2 direction by the driving force of the first motor 40. The workpiece 12 has a plurality of teeth 60. Each of the plurality of teeth 60 is formed with a workpiece tooth surface 62. The workpiece tooth surface 62 includes a left workpiece tooth surface 62a and a right workpiece tooth surface 62b.

[0020] The grinding tool 14 is attached to the tool mounting shaft 56. The grinding tool 14 can rotate in the R3 direction and the R4 direction by the driving force of the second motor 58. The grinding tool 14 is a tool for grinding the workpiece 12. The grinding tool 14 has a spiral grinding tooth 64. The grinding tooth 64 is formed with a grinding tooth surface 66. The grinding tooth surface 66 includes a first grinding tooth surface 66a and a second grinding tooth surface 66b. For example, a single layer of CBN (cubic boron nitride) abrasive grains or the like is electrodeposited on the grinding tooth surface 66 via a nickel plating layer.

[0021] When grinding the workpiece 12 with the grinding tool 14, the workpiece 12 and the grinding tool 14 are engaged. With the workpiece 12 and the grinding tool 14 engaged, the left workpiece tooth flank 62a faces the first grinding tooth flank 66a, and the right workpiece tooth flank 62b faces the second grinding tooth flank 66b. With the workpiece 12 and the grinding tool 14 engaged, for example, by rotating the workpiece 12 in the R1 direction and rotating the grinding tool 14 in the R3 direction, the left workpiece tooth flank 62a can be ground by the first grinding tooth flank 66a, and the right workpiece tooth flank 62b can be ground by the second grinding tooth flank 66b. In addition, with the workpiece 12 and the grinding tool 14 engaged, for example, by rotating the workpiece 12 in the R2 direction and rotating the grinding tool 14 in the R4 direction, the left workpiece tooth surface 62a can be ground by the first grinding tooth surface 66a and the right workpiece tooth surface 62b can be ground by the second grinding tooth surface 66b.

[0022] The grinding system 10 further includes a first encoder 68 and a second encoder 70. The first encoder 68 is provided on the first motor 40. The first encoder 68 outputs information (e.g., a pulse signal) relating to the rotational phase (rotational speed, rotation angle, rotational position, and rotation amount) of the workpiece 12 to the control device 26.

[0023] The second encoder 70 is provided on the second motor 58. The second encoder 70 outputs information (for example, a pulse signal) relating to the rotational phase (rotational speed, rotational angle, rotational position, and rotation amount) of the grinding tool 14 to the control device 26.

[0024] The control device 26 includes a first servo amplifier 74, a second servo amplifier 76, and a control main body 78. The first servo amplifier 74 controls the rotation of the first motor 40 based on a signal output from the control main body 78. The second servo amplifier 76 controls the rotation of the second motor 58 based on a signal output from the control main body 78.

[0025] The control main body 78 includes a calculation unit 80, a storage unit 82, an operation unit 84, and a display unit 86. The calculation unit 80 is configured by a processor such as a CPU (Central Processing Unit) or a GPU (Graphics Processing Unit). In other words, the calculation unit 80 is configured by processing circuitry.

[0026] The calculation unit 80 has a control unit 88, a grinding control unit 90, an information acquisition unit 92, and a correction information generation unit 94. The control unit 88 controls the cutting motor 30, the traverse motor 34, a swing motor (not shown), and the shift motor 48. The grinding control unit 90 controls the rotation of the workpiece 12 via the first servo amplifier 74. The grinding control unit 90 also controls the rotation of the grinding tool 14 via the second servo amplifier 76. The information acquisition unit 92 acquires information output from the first encoder 68 and information output from the second encoder 70. The correction information generation unit 94 generates first correction information 104 and second correction information 110, which will be described later.

[0027] The control unit 88, the grinding control unit 90, the information acquisition unit 92, and the correction information generation unit 94 can be realized by the calculation unit 80 executing a program stored in the storage unit 82. At least a portion of the control unit 88, the grinding control unit 90, the information acquisition unit 92, and the correction information generation unit 94 may be realized by an integrated circuit such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field-Programmable Gate Array). At least a portion of the control unit 88, the grinding control unit 90, the information acquisition unit 92, and the correction information generation unit 94 may be configured by an electronic circuit including discrete devices.

[0028] The storage unit 82 is composed of a volatile memory (not shown) and a non-volatile memory (not shown). An example of the volatile memory is a random access memory (RAM). The volatile memory is used as a working memory for the processor, and temporarily stores data necessary for processing or calculation. An example of the non-volatile memory is a read-only memory (ROM) or a flash memory. The non-volatile memory is used as a storage memory, and stores programs, tables, maps, etc. At least a part of the storage unit 82 may be provided in the processor, integrated circuit, etc. described above.

[0029] The operation unit 84 is used when the user operates the control device 26. The operation unit 84 may include a keyboard, a mouse, etc. The display unit 86 is provided with a display element (not shown). For example, a liquid crystal display element, an organic electroluminescence display element, etc. may be used as the display element. The operation unit 84 and the display unit 86 may be configured by a touch panel (not shown) provided with such a display element.

[0030] Next, an example of a method for grinding the workpiece 12 will be described. Fig. 3 is a flowchart showing an example of the method for grinding the workpiece 12. The workpiece 12 is subjected to heat treatment before grinding. In this case, the workpiece 12 may be deformed into an elliptical shape due to thermal distortion when viewed from the direction of the rotation axis of the workpiece 12.

[0031] In step S1, the workpiece 12 is attached to the gear mounting shaft 38, and the grinding tool 14 is attached to the tool mounting shaft 56. After this, the process proceeds to step S2.

[0032] In step S2, the workpiece 12 is meshed with the grinding tool 14. Specifically, the control unit 88 controls the cutting motor 30, the traverse motor 34, a turning motor (not shown), and the shift motor 48 to mesh the workpiece 12 with the grinding tool 14. After this, the process proceeds to step S3.

[0033] In step S3, a first grinding step is performed. In the first grinding step, the workpiece tooth surface 62 is roughly ground (first rough grinding). The grinding control unit 90 rotates the workpiece 12 via the first servo amplifier 74 and rotates the grinding tool 14 via the second servo amplifier 76. The grinding control unit 90 rotates the workpiece 12 and the grinding tool 14 synchronously. In other words, based on the information output from the first encoder 68 and the information output from the second encoder 70, the grinding control unit 90 feedback-controls the first servo amplifier 74 and the second servo amplifier 76 so that the workpiece 12 and the grinding tool 14 rotate while maintaining an engaged state.

[0034] In the first grinding step, grinding is performed around the entire circumference of the workpiece 12 (on all of the workpiece tooth surfaces 62). If the workpiece 12 is deformed due to thermal distortion, runout of the workpiece tooth surfaces 62 relative to the grinding tooth surfaces 66 may occur in the first grinding step. After this, the process proceeds to step S4.

[0035] In step S4, a first correction information generating step is performed. Fig. 4 is an explanatory diagram of the first correction information generating step. In Fig. 4, the horizontal axis indicates the rotational phase of the workpiece 12, and the vertical axis indicates the rotational phase difference of the workpiece 12. In the first correction information generating step, the difference (rotational phase difference) between the command value of the rotational phase of the workpiece 12 during the first grinding step and the detected value of the rotational phase of the workpiece 12 is acquired as the amount of runout of the workpiece tooth surface 62 relative to the grinding tooth surface 66. The rotational phase difference of the workpiece 12 indicates a synchronization error in the rotation of the workpiece 12.

[0036] As shown in FIG. 4, in the first correction information generating step, the correction information generating unit 94 generates a first runout waveform 102 by sinusoidal approximation of a runout waveform 100, which indicates the relationship between the runout amount of the workpiece tooth surface 62 relative to the grinding tooth surface 66 during the first grinding step and the rotational phase of the workpiece 12. In other words, the first runout waveform 102 indicates the change in the runout amount of the workpiece tooth surface 62 over one rotation of the workpiece 12 during the first grinding step. In other words, the first runout waveform 102 indicates the grinding error of the first grinding step. Also, in the first correction information generating step, the correction information generating unit 94 generates first correction information 104 by inverting the first runout waveform 102. The first correction information 104 is information indicating a waveform obtained by inverting the first runout waveform 102 in the direction of the vertical axis of FIG. 4 (the direction of the swing width of the first runout waveform 102). After this, the process proceeds to step S5.

[0037] In step S5, a second grinding step is performed. In the second grinding step, the workpiece tooth surface 62 is roughly ground (second rough grinding). In the second grinding step, the grinding control unit 90 changes the rotation speed of the workpiece 12 based on the first correction information 104 while the workpiece 12 and the grinding tool 14 are meshed and rotating, thereby grinding the workpiece tooth surface 62 with the grinding tooth surface 66. In other words, the grinding control unit 90 outputs a command signal generated based on the synchronous rotation signal of the workpiece 12 and the first correction information 104 to the first servo amplifier 74, and outputs a synchronous rotation signal of the grinding tool 14 to the second servo amplifier 76, thereby grinding the workpiece tooth surface 62 with the grinding tooth surface 66. That is, in the second grinding step, the grinding control unit 90 feedback-controls the rotation speed of the workpiece 12 so that the grinding error generated in the first grinding step is reduced (the contact component is corrected).

[0038] As a result, in the second grinding step, the grinding error that occurred in the first grinding step can be reduced. Note that in the second grinding step, the workpiece tooth surface 62 may be ground by the grinding tooth surface 66 by changing the rotation speed of the grinding tool 14 based on the first correction information 104 while the workpiece 12 and the grinding tool 14 are rotated in mesh with each other. After this, the process proceeds to step S6.

[0039] In step S6, a second correction information generating step is performed. Fig. 5 is an explanatory diagram of the second correction information generating step. In Fig. 5, the horizontal axis represents the rotational phase of the workpiece 12, and the vertical axis represents the rotational phase difference of the workpiece 12.

[0040] As shown in FIG. 5, in the second correction information generating step, the correction information generating unit 94 generates a second runout waveform 108 by sinusoidally approximating a runout waveform 106, which indicates the relationship between the runout amount of the workpiece tooth surface 62 relative to the grinding tooth surface 66 during the second grinding step and the rotational phase of the workpiece 12. In other words, the second runout waveform 108 indicates the change in the runout amount of the workpiece tooth surface 62 over one rotation of the workpiece 12 during the second grinding step. In other words, the second runout waveform 108 indicates the grinding error of the second grinding step. Also, in the second correction information generating step, the correction information generating unit 94 generates second correction information 110 by inverting the second runout waveform 108. The second correction information 110 is information indicating a waveform obtained by inverting the second runout waveform 108 in the direction of the vertical axis of FIG. 5 (the direction of the swing width of the second runout waveform 108). After this, the process proceeds to step S7.

[0041] In step S7, a third grinding step is performed. In the third grinding step, the workpiece tooth surface 62 is finish-ground. In the third grinding step, the grinding control unit 90 changes the rotational speed of the workpiece 12 based on the second correction information 110 while the workpiece 12 and the grinding tool 14 are meshed and rotating, thereby grinding the workpiece tooth surface 62 with the grinding tooth surface 66. In other words, the grinding control unit 90 outputs a command signal generated based on the synchronous rotation signal of the workpiece 12 and the second correction information 110 to the first servo amplifier 74, and outputs a synchronous rotation signal of the grinding tool 14 to the second servo amplifier 76, thereby grinding the workpiece tooth surface 62 with the grinding tooth surface 66. That is, in the third grinding step, the grinding control unit 90 feedback-controls the rotational speed of the workpiece 12 so that the grinding error generated in the second grinding step is reduced (the contact component is corrected).

[0042] 6 is a graph showing a runout waveform 112 in the third grinding step. As shown in FIG. 6, in the third grinding step, the grinding error generated in the second grinding step can be reduced, so that the workpiece tooth surface 62 can be ground with higher precision. Note that in the third grinding step, the workpiece tooth surface 62 may be ground with the grinding tooth surface 66 by changing the rotational speed of the grinding tool 14 based on the second correction information 110 while the workpiece 12 and the grinding tool 14 are rotated in mesh with each other. After this, the processing of FIG. 3 is completed.

[0043] According to this embodiment, the second grinding step is performed based on first correction information 104 generated by inverting a first runout waveform 102 that indicates the relationship between the runout amount of the workpiece tooth surface 62 during the first grinding step and the rotational phase of the workpiece 12. This makes it possible to reduce the grinding error that occurred in the first grinding step in the second grinding step. Therefore, the workpiece tooth surface 62 can be ground with high precision. Therefore, a better grinding method for the workpiece 12 and a grinding system 10 can be provided.

[0044] The following additional notes are further disclosed regarding the above embodiment.

[0045] (Appendix 1) The workpiece grinding method of the present disclosure includes a first grinding step in which a gear-shaped workpiece (12) and a grinding tool (14) are meshed and rotated to grind a workpiece tooth surface (62) of the workpiece with a spiral grinding tooth surface (66) of the grinding tool; a first correction information generation step in which first correction information (104) is generated by inverting a first runout waveform (102) that indicates the relationship between the amount of runout of the workpiece tooth surface relative to the grinding tooth surface during the first grinding step and the rotational phase of the workpiece; and a second grinding step in which, while the workpiece and the grinding tool are meshed and rotated, the workpiece tooth surface is ground with the grinding tooth surface by changing the rotational speed of the workpiece or the grinding tool based on the first correction information.

[0046] According to this configuration, the second grinding step is performed based on the first correction information generated by inverting the first deflection waveform, which indicates the relationship between the contact amount of the workpiece tooth surface and the rotational phase of the workpiece during the first grinding step. This makes it possible to reduce the grinding error that occurred in the first grinding step in the second grinding step. Therefore, the workpiece tooth surface can be ground with high precision. Therefore, a better workpiece grinding method can be provided.

[0047] (Appendix 2) In the method for grinding a workpiece described in Appendix 1, in the first correction information generation step, the difference between the command value of the rotational phase of the workpiece during the first grinding step and the detected value of the rotational phase of the workpiece may be obtained as the runout amount.

[0048] According to this configuration, the first correction information can be generated easily.

[0049] (Appendix 3) The method for grinding a workpiece according to Supplementary Note 1 or 2 may include a second correction information generating step of generating second correction information (110) by inverting a second runout waveform (108) that indicates the relationship between the amount of runout of the workpiece tooth surface relative to the grinding tooth surface during the second grinding step and the rotational phase of the workpiece; and a third grinding step of grinding the workpiece tooth surface with the grinding tooth surface by changing the rotational speed of the workpiece or the grinding tool based on the second correction information while the workpiece and the grinding tool are rotated in mesh with each other.

[0050] According to this configuration, the third grinding step is performed based on the second correction information generated by inverting the second runout waveform, which indicates the relationship between the runout amount of the workpiece tooth surface during the second grinding step and the rotational phase of the workpiece. This makes it possible to reduce the grinding error that occurred in the second grinding step in the third grinding step. Therefore, the grinding tooth surface can be ground with even greater precision.

[0051] (Appendix 4) The grinding system (10) of the present disclosure comprises a grinding control unit (90) that performs a first grinding step in which a gear-shaped workpiece is rotated in mesh with a grinding tool to grind the workpiece tooth surface with the spiral grinding tooth surface of the grinding tool, and a correction information generation unit (94) that generates first correction information by inverting a first runout waveform that indicates the relationship between the amount of runout of the workpiece tooth surface relative to the grinding tooth surface during the first grinding step and the rotational phase of the workpiece, and the grinding control unit further performs a second grinding step in which the workpiece tooth surface is ground with the grinding tooth surface by changing the rotational speed of the workpiece or the grinding tool based on the first correction information while the workpiece is rotated in mesh with the grinding tool.

[0052] This configuration provides the same effect as in Supplementary Note 1. Therefore, a better grinding system can be provided.

[0053] (Appendix 5) In the grinding system described in Appendix 4, the correction information generation unit may acquire the difference between the command value of the rotational phase of the workpiece during the first grinding step and the detected value of the rotational phase of the workpiece as the runout amount.

[0054] According to this configuration, the same effect as in Supplementary Note 2 can be achieved.

[0055] (Appendix 6) In the grinding system described in Appendix 4 or 5, the correction information generating unit generates second correction information by inverting a second runout waveform indicating the relationship between the amount of runout of the workpiece tooth surface relative to the grinding tooth surface during the second grinding step and the rotational phase of the workpiece, and the grinding control unit may further perform a third grinding step in which the workpiece tooth surface is ground with the grinding tooth surface by changing the rotational speed of the workpiece or the grinding tool based on the second correction information while the workpiece and the grinding tool are meshed and rotating.

[0056] According to this configuration, the same effect as that of Supplementary Note 3 can be achieved.

[0057] Although the present disclosure has been described in detail, the present disclosure is not limited to the individual embodiments described above. Various additions, substitutions, modifications, partial deletions, etc. are possible in these embodiments without departing from the gist of the present disclosure or the spirit of the present disclosure derived from the content of the claims and their equivalents. These embodiments can also be implemented in combination. For example, in the above-described embodiments, the order of each operation and the order of each process are shown as examples and are not limited to these. The same applies when numerical values ​​or mathematical expressions are used in the description of the above-described embodiments. [Explanation of symbols]

[0058] 10...Grinding system 12...Workpiece 14...Grinding tool 62...Workpiece tooth surface 64...Grounding tooth 66...Grounding tooth surface 88...Control unit 90...Grinding control unit 94... Correction information generating unit 102... First deflection waveform 104...First correction information 108...Second deflection waveform 110...Second Correction Information

Claims

1. a first grinding step in which a gear-shaped workpiece and a grinding tool are meshed and rotated to grind a workpiece tooth surface of the workpiece with a spiral grinding tooth surface of the grinding tool; A difference between a command value of the rotational phase of the workpiece during the first grinding step and a detected value of the rotational phase of the workpiece is acquired as a runout amount of the workpiece tooth surface relative to the grinding tooth surface during the first grinding step; a first correction information generating step of generating first correction information by inverting a first deflection waveform that is approximated to a sine wave, the first deflection waveform indicating the relationship between the deflection amount of the work tooth surface and the rotation phase of the work; a second grinding step of grinding the work tooth surface with the grinding tooth surface by changing the rotation speed of the work or the grinding tool based on the first correction information while the work and the grinding tool are rotated in mesh with each other; A method for grinding a workpiece, comprising:

2. 2. The method for grinding a workpiece according to claim 1, a second correction information generating step of generating second correction information by inverting a second deflection waveform approximated to a sine wave, the second deflection waveform indicating the relationship between the amount of deflection of the workpiece tooth surface relative to the grinding tooth surface during the second grinding step and the rotational phase of the workpiece; a third grinding step of grinding the work tooth surface with the grinding tooth surface by changing the rotation speed of the work or the grinding tool based on the second correction information while the work and the grinding tool are rotated in mesh with each other; A method for grinding a workpiece, comprising:

3. a grinding control unit that performs a first grinding step of grinding a work tooth surface of a gear-shaped workpiece with a grinding tool by rotating the workpiece while meshing the work tooth surface with a spiral grinding tooth surface of the grinding tool; A difference between a command value of the rotational phase of the workpiece during the first grinding step and a detected value of the rotational phase of the workpiece is acquired as a runout amount of the workpiece tooth surface relative to the grinding tooth surface during the first grinding step; a correction information generating unit that generates first correction information by inverting a first deflection waveform that is approximated to a sine wave, the first deflection waveform indicating the relationship between the deflection amount of the tooth surface of the workpiece and the rotation phase of the workpiece; Equipped with The grinding control unit further performs a second grinding step of grinding the work tooth surface with the grinding tooth surface by changing the rotation speed of the work or the grinding tool based on the first correction information while the work and the grinding tool are meshed and rotating.

4. 4. The grinding system of claim 3, the correction information generating unit indicates a relationship between a runout amount of the workpiece tooth surface relative to the grinding tooth surface during the second grinding step and a rotation phase of the workpiece, and generates second correction information by inverting a second runout waveform that is approximated to a sine wave; The grinding control unit further performs a third grinding step of grinding the work tooth surface with the grinding tooth surface by changing the rotation speed of the work or the grinding tool based on the second correction information while the work and the grinding tool are meshed and rotating.

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