Grinding system and control method of grinding system

Abstract

The invention provides a grinding system and a control method of the grinding system. A grinding system (10) is provided with: a signal acquisition unit (90) that acquires a first signal and a second signal; a synchronization signal generation unit (92) that generates a synchronization signal for synchronously rotating the first rotating body (106) with respect to the second rotating body (108) on the basis of the first signal and the second signal; a command signal generation unit (96) that generates a command signal on the basis of a predetermined cancel signal for suppressing a variation in the rotational speed of the first rotating body caused by a cogging effect of a motor that rotates the first rotating body, and a synchronization signal; and a signal output unit (98) that outputs the command signal generated by the command signal generation unit and controls the motor. Therefore, a better grinding system and a control method of the grinding system can be provided.

Description

Technical Field

[0001] The present invention relates to a grinding system and a method for controlling the grinding system. Background Art

[0002] Japanese Patent Application No. 5467833 discloses a grinding system that grinds a gear-shaped workpiece (work) and a grinding tool by meshing and rotating them, thereby grinding the workpiece tooth surface of the workpiece with the helical grinding tooth surface of the grinding tool. Summary of the Invention

[0003] We look forward to better grinding systems and grinding system control methods.

[0004] The purpose of the present invention is to solve the above technical problems.

[0005] A first embodiment of the present invention is a grinding system that grinds a workpiece tooth surface of a gear-shaped workpiece and a grinding tool by meshing and rotating the workpiece with the spiral grinding tooth surface of the grinding tool, wherein one of the workpiece and the grinding tool is a first rotating body, and the other of the workpiece and the grinding tool is a second rotating body, and the grinding system includes a signal acquisition unit, a synchronization signal generation unit, an instruction signal generation unit, and a signal output unit, wherein the signal acquisition unit acquires a first signal indicating the rotation speed of the first rotating body and a second signal indicating the rotation speed of the second rotating body; the synchronization signal generation unit generates a synchronization signal for causing the first rotating body to rotate synchronously with the second rotating body based on the first signal and the second signal; the instruction signal generation unit generates an instruction signal based on a predetermined cancellation signal and the synchronization signal, the cancellation signal being used to suppress fluctuations in the rotation speed of the first rotating body caused by a cogging effect of a motor that rotates the first rotating body; and the signal output unit outputs the instruction signal generated by the instruction signal generation unit to control the motor.

[0006] A second aspect of the present invention is a method for controlling a grinding system, wherein the grinding system grinds the tooth surface of the workpiece with the spiral grinding tooth surface of the grinding tool by meshing and rotating a gear-shaped workpiece and a grinding tool, wherein one of the workpiece and the grinding tool is a first rotating body, and the other of the workpiece and the grinding tool is a second rotating body, and the method for controlling the grinding system comprises a signal acquisition step, a synchronization signal generation step, an instruction signal generation step, and a signal output step, wherein, in the signal acquisition step, a first signal indicating the rotation speed of the first rotating body and a signal indicating the rotation speed of the first rotating body are acquired. a second signal of the rotational speed of the second rotating body; in the synchronization signal generating step, a synchronization signal for causing the first rotating body to rotate synchronously with the second rotating body is generated based on the first signal and the second signal; in the command signal generating step, a command signal is generated based on a predetermined cancellation signal and the synchronization signal, the cancellation signal being used to suppress changes in the rotational speed of the first rotating body caused by the cogging effect of the motor that causes the first rotating body to rotate; in the signal output step, the command signal generated by the command signal generating step is output to control the motor.

[0007] According to the present invention, a more excellent grinding system and a method for controlling the grinding system can be provided.

[0008] The above-mentioned objects, features and advantages will be easily understood from the following description of the embodiments with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 It is a perspective view of a grinding system according to an embodiment.

[0010] Figure 2 It is the control block diagram of the grinding system.

[0011] Figure 3 This is a flowchart showing an example of a control method of a grinding system.

[0012] Figure 4 is a flowchart illustrating the cancel signal determination steps.

[0013] Figure 5 It is a flowchart explaining the grinding steps. DETAILED DESCRIPTION

[0014] In recent years, efforts to achieve a low-carbon or decarbonized society have been actively pursued. To reduce CO2 emissions and improve energy efficiency, research and development of electric vehicles (hybrid vehicles, fuel cell vehicles, etc.) are underway. Compared to conventional, general gasoline-powered vehicles, such electric vehicles produce less noise when the vehicle is driven. Therefore, in electric vehicles, the noise generated by gear rotation is required to be reduced compared to gasoline-powered vehicles. In a grinding system, the rotational speed of a workpiece fluctuates due to the cogging of the motor that rotates the workpiece. Specifically, the rotational speed of the workpiece fluctuates by a number of times corresponding to the number of pole pairs of the motor's north and south poles per rotation of the workpiece. When the rotational speed of the workpiece fluctuates in this way, it is sometimes impossible to grind the workpiece tooth surface with high precision. When a product gear obtained by grinding the workpiece tooth surface is used, grinding errors on the workpiece tooth surface caused by the cogging of the motor sometimes result in noise. The present invention can provide a grinding system and a control method for the grinding system that can reduce grinding errors on the workpiece tooth surface caused by the cogging of the motor.

[0015] Figure 1 : is a perspective view of the grinding system 10 involved in the embodiment. Figure 1 As shown, 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.

[0016] The bed 16 is placed on a horizontal surface in a factory, for example. The gear support mechanism 18 is arranged on the flat upper surface of the bed 16. The gear support mechanism 18 includes a feed table (cutting table) 28, a feed motor (cutting motor) 30, a traverse table 32, and a traverse motor 34.

[0017] The feed 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 feed table 28 is connected to the feed motor 30 via a ball screw shaft 36. The feed motor 30 rotates the ball screw shaft 36 to move the feed table 28 in the direction A.

[0018] The traverse table 32 is disposed on the upper surface of the feed table 28. The traverse table 32 moves relative to the feed table 28 in the direction B. The direction B is perpendicular to the height direction of the bed 16 and the direction A. The traverse table 32 is connected to the traverse motor 34 via a ball screw shaft (not shown). The traverse motor 34 rotates the ball screw shaft to move the traverse table 32 in the direction B.

[0019] The gear rotating mechanism 20 is disposed on the upper surface of the traverse table 32. The gear rotating mechanism 20 includes a gear mounting shaft 38 and a first motor 40. The gear mounting shaft 38 extends in the direction B. The workpiece 12 is attachable to and detachable from the gear mounting shaft 38. The first motor 40 rotates the gear mounting shaft 38.

[0020] The tool support mechanism 22 includes a column 42, a rotary 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 rotary table 44 is mounted on the surface of the column 42 facing the gear support mechanism 18.

[0021] The turntable 44 extends in one direction. A rotary motor (not shown) rotates the turntable 44 in the C direction relative to the column 42. A displacement table 46 is provided on the surface of the turntable 44 facing the gear support mechanism 18. The displacement table 46 is connected to a displacement motor 48 via a ball screw shaft 50. The displacement motor 48 is mounted on the turntable 44. The displacement motor 48 moves the displacement table 46 in the D direction relative to the turntable 44.

[0022] The tool rotation mechanism 24 includes a base 54, a tool mounting shaft 56, and a second motor 58. The base 54 is mounted on the surface of the displacement table 46 facing the gear support mechanism 18. The base 54 extends along the direction in which the turntable 44 extends. The tool mounting shaft 56 penetrates the base 54 along the direction in which the base 54 extends. The grinding tool 14 is attachable to and detachable from the tool mounting shaft 56. The second motor 58 rotates the tool mounting shaft 56.

[0023] like Figure 2 As shown, the workpiece 12 is mounted on the gear mounting shaft 38. The workpiece 12 can rotate 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 teeth 60 has a workpiece tooth surface 62. The workpiece tooth surface 62 includes a left workpiece tooth surface 62a and a right workpiece tooth surface 62b.

[0024] The grinding tool 14 is mounted on 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 spiral grinding teeth 64. Grinding tooth surfaces 66 are formed on the grinding teeth 64. The grinding tooth surfaces 66 include a first grinding tooth surface 66a and a second grinding tooth surface 66b. A single layer of CBN (cubic boron nitride) abrasive grains, for example, is electrodeposited on the grinding tooth surfaces 66 via a nickel plating layer.

[0025] When grinding the workpiece 12 using the grinding tool 14, the workpiece 12 is meshed with the grinding tool 14. While the workpiece 12 and the grinding tool 14 are meshed, the left workpiece tooth surface 62a faces the first grinding tooth surface 66a, and the right workpiece tooth surface 62b faces the second grinding tooth surface 66b. While the workpiece 12 and the grinding tool 14 are meshed, for example, by rotating the workpiece 12 in the R1 direction and the grinding tool 14 in the R3 direction, the left workpiece tooth surface 62a can be ground with the first grinding tooth surface 66a, and the right workpiece tooth surface 62b can be ground with the second grinding tooth surface 66b. Alternatively, while the workpiece 12 and the grinding tool 14 are meshed, for example, by rotating the workpiece 12 in the R2 direction and the grinding tool 14 in the R4 direction, the left workpiece tooth surface 62a can be ground with the first grinding tooth surface 66a, and the right workpiece tooth surface 62b can be ground with the second grinding tooth surface 66b.

[0026] 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) related to the rotation phase (rotation speed, rotation angle, rotation position, rotation amount) of the workpiece 12 to the control device 26.

[0027] The second encoder 70 is provided on the second motor 58 . The second encoder 70 outputs information (eg, a pulse signal) related to the rotation phase (rotation speed, rotation angle, rotation position, rotation amount) of the grinding tool 14 to the control device 26 .

[0028] The control device 26 includes a first servo amplifier 74, a second servo amplifier 76, and a control main unit 78. The first servo amplifier 74 controls the rotation of the first motor 40 based on a command signal output by the control main unit 78. The second servo amplifier 76 controls the rotation of the second motor 58 based on a command signal output by the control main unit 78.

[0029] The control main unit 78 includes a computing unit 80, a storage unit 82, an operating unit 84, and a display unit 86. The computing unit 80 is composed of a processor such as a CPU (Central Processing Unit) or a GPU (Graphics Processing Unit). In other words, the computing unit 80 is composed of processing circuitry.

[0030] The computing unit 80 includes a control unit 88, a signal acquisition unit 90, a synchronization signal generation unit 92, a cancel signal determination unit 94, a command signal generation unit 96, a signal output unit 98, a determination unit 100, a phase search unit 102, and an amplitude search unit 104. The control unit 88 controls the feed motor 30, the traverse motor 34, the rotation motor (not shown), and the displacement motor 48. The signal acquisition unit 90 acquires a first signal indicating the rotational speed of the workpiece 12 and a second signal indicating the rotational speed of the grinding tool 14. The signal acquisition unit 90 acquires the first signal based on information output by the first encoder 68. The signal acquisition unit 90 acquires the second signal based on information output by the second encoder 70.

[0031] The synchronization signal generating unit 92 generates a synchronization signal (workpiece axis speed command signal) for causing the workpiece 12 to rotate synchronously with the grinding tool 14 based on the first and second signals. The synchronization signal is a voltage signal corresponding to the rotational speed of the workpiece 12. Alternatively, the synchronization signal may be a digital signal. The cancellation signal determining unit 94 determines a cancellation signal for suppressing fluctuations in the rotational speed of the workpiece 12 caused by the cogging of the first motor 40. The command signal generating unit 96 generates a command signal based on the cancellation signal and the synchronization signal. The signal output unit 98 outputs the command signal generated by the command signal generating unit 96 to the first servo amplifier 74, thereby controlling the rotation of the first motor 40. The command signal is an analog signal. Alternatively, if the first servo amplifier 74 corresponds to a digital signal, the command signal may also be a digital signal. The determination unit 100 performs the determination processing described below. The phase search unit 102 searches for the optimal phase of a candidate signal that is a candidate for the cancellation signal. The amplitude search unit 104 searches for the optimal amplitude of the candidate signal.

[0032] The control unit 88, signal acquisition unit 90, synchronization signal generation unit 92, cancellation signal determination unit 94, command signal generation unit 96, signal output unit 98, determination unit 100, phase search unit 102, and amplitude search unit 104 can be implemented by the calculation unit 80 executing a program stored in the storage unit 82. Furthermore, at least a portion of the control unit 88, signal acquisition unit 90, synchronization signal generation unit 92, cancellation signal determination unit 94, command signal generation unit 96, signal output unit 98, determination unit 100, phase search unit 102, and amplitude search unit 104 can be implemented by an integrated circuit such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field-Programmable Gate Array). In addition, at least a portion of the control unit 88, signal acquisition unit 90, synchronization signal generation unit 92, cancellation signal determination unit 94, instruction signal generation unit 96, signal output unit 98, determination unit 100, phase search unit 102, and amplitude search unit 104 may be configured by an electronic circuit including discrete devices.

[0033] The storage unit 82 is composed of a volatile memory (not shown) and a non-volatile memory (not shown). Examples of volatile memory include RAM (Random Access Memory). Volatile memory is used as working memory for the processor, temporarily storing data required for processing or calculations. Examples of non-volatile memory include ROM (Read Only Memory) and flash memory. Non-volatile memory is used as storage memory, storing programs, tables, maps, etc. At least a portion of the storage unit 82 may be provided on the processor, integrated circuit, etc. described above.

[0034] The operating unit 84 is used by the user to operate the control device 26. Furthermore, the operating unit 84 may include a keyboard, a mouse, or the like. A display element (not shown) is provided on the display unit 86. Examples of such display elements include liquid crystal display elements and organic electroluminescent display elements. Alternatively, the operating unit 84 and the display unit 86 may be configured using a touch panel (not shown) having such a display element.

[0035] Next, an example of a control method of the grinding system 10 will be described. Figure 3 This is a flowchart showing an example of a control method of the grinding system 10 . Figure 4 is a flowchart illustrating the cancel signal determination steps. Figure 5 This is a flowchart illustrating a grinding procedure. In this embodiment, an example of grinding a plurality of workpieces 12 will be described.

[0036] like Figure 3 As shown, in step S1, a cancel signal determination step is performed. In the cancel signal determination step, the workpiece 12 is mounted on the gear mounting shaft 38, and the grinding tool 14 is mounted on the tool mounting shaft 56. Then, in the cancel signal determination step, while the workpiece 12 (first rotating body 106) and the grinding tool 14 (second rotating body 108) are rotating without engaging with each other, the phase and amplitude of candidate signals serving as cancellation signals are adjusted. The candidate signal that minimizes the variation in the rotational speed of the workpiece 12 caused by the cogging of the first motor 40 (the motor that rotates the first rotating body 106) is determined as the cancel signal.

[0037] That is, in the cancel signal determination step, if Figure 4 As shown, a phase search step is performed in step S10. In this phase search step, the phase search unit 102 rotates the workpiece 12 while changing the phase of the candidate signal while maintaining the amplitude of the candidate signal constant. This process searches for the optimal phase of the candidate signal that minimizes the fluctuation in the rotational speed of the workpiece 12. The candidate signal is a sine wave having a frequency corresponding to the frequency of the rotational speed fluctuation of the workpiece 12 caused by cogging. In other words, the frequency of the candidate signal is the same as the frequency of the rotational speed fluctuation of the workpiece 12 caused by cogging.

[0038] Specifically, in the phase search step, while the workpiece 12 and the grinding tool 14 are rotating without engaging each other, the synchronization signal generator 92 generates a synchronization signal for synchronously rotating the workpiece 12 relative to the grinding tool 14 based on the first and second signals. Furthermore, the cancel signal determiner 94 generates a candidate signal. Furthermore, the command signal generator 96 generates a command signal based on the synchronization signal generated by the synchronization signal generator 92 and the candidate signal generated by the cancel signal determiner 94. The signal output unit 98 outputs the command signal generated by the command signal generator 96 to the first servo amplifier 74. The signal acquisition unit 90 acquires a first signal indicating the rotational speed of the workpiece 12 and a second signal indicating the rotational speed of the grinding tool 14.

[0039] During the phase search step, the amplitude of the candidate signal is maintained constant until the phase search step ends. During the phase search step, the phase of the candidate signal is updated (changed) each time the workpiece 12 rotates by the candidate signal holding angle. In other words, during the phase search step, the workpiece 12 is rotated by a predetermined candidate signal holding angle while maintaining the phase of the candidate signal constant. The candidate signal holding angle is determined based on the period at which the cogging of the first motor 40 occurs. In other words, the candidate signal holding angle is determined as the rotation angle of the workpiece 12 that causes the cogging of the first motor 40. The cancellation signal determination unit 94 performs frequency analysis (Fourier transform) on the data within the range of the workpiece 12's rotational speed corresponding to the candidate signal holding angle and obtains an amplitude component having the same frequency as the cogging frequency of the first motor 40. This amplitude component represents the fluctuation in the rotational speed of the workpiece 12 caused by the cogging of the first motor 40. During the phase search step, the phase of the candidate signal that minimizes the fluctuation in the rotational speed of the workpiece 12 caused by the cogging of the first motor 40 is determined as the optimal phase. After that, transfer to step S11.

[0040] In step S11, an amplitude search step is performed. In the amplitude search step, the amplitude search unit 104 rotates the workpiece 12 while changing the amplitude of the candidate signal while maintaining the phase of the candidate signal at the optimal signal, thereby searching for the optimal amplitude of the candidate signal that minimizes the change in the rotational speed of the first motor 40.

[0041] Specifically, in the amplitude search step, while the workpiece 12 and the grinding tool 14 are rotating without engaging each other, the synchronization signal generator 92 generates a synchronization signal for synchronously rotating the workpiece 12 relative to the grinding tool 14 based on the first and second signals. Furthermore, the cancel signal determiner 94 generates a candidate signal. Furthermore, the command signal generator 96 generates a command signal based on the synchronization signal generated by the synchronization signal generator 92 and the candidate signal generated by the cancel signal determiner 94. The signal output unit 98 outputs the command signal generated by the command signal generator 96 to the first servo amplifier 74. The signal acquisition unit 90 acquires the first signal indicating the rotational speed of the workpiece 12 and the second signal indicating the rotational speed of the grinding tool 14.

[0042] In the amplitude search step, the phase of the candidate signal is maintained at the optimal phase found by the search in the phase search step until the amplitude search step is completed. In the amplitude search step, the amplitude of the candidate signal is updated (changed) each time the workpiece 12 rotates by the candidate signal holding angle. In other words, in the amplitude search step, the workpiece 12 is rotated by the candidate signal holding angle while the amplitude of the candidate signal is kept constant. The cancellation signal determination unit 94 performs frequency analysis (Fourier transform) on the data in the range of the rotation speed of the workpiece 12 corresponding to the candidate signal holding angle, and obtains the amplitude component of the same frequency as the frequency of the cogging effect of the first motor 40. In the amplitude search step, the amplitude of the candidate signal with the smallest change in the rotation speed of the workpiece 12 caused by the cogging effect of the first motor 40 is determined as the optimal amplitude. The cancellation signal determination unit 94 determines the candidate signal with the optimal phase and optimal amplitude as the cancellation signal. Then, transfer to step S2.

[0043] like Figure 3 As shown, in step S2, a grinding step is performed. In the grinding step, the workpiece 12 and the grinding tool 14 are meshed with each other and rotated, whereby the workpiece tooth surface 62 of the workpiece 12 is ground by the grinding tooth surface 66 of the grinding tool 14. In this case, as Figure 5 As shown, in step S20 , the workpiece 12 and the grinding tool 14 are brought into engagement with each other. In step S20 , a signal acquisition step is performed. In the signal acquisition step, the signal acquisition unit 90 acquires a first signal indicating the rotation speed of the workpiece 12 and a second signal indicating the rotation speed of the grinding tool 14 . Thereafter, the process moves to step S21 .

[0044] In step S21, a synchronization signal generation step is performed. In this step, the synchronization signal generation unit 92 generates a synchronization signal for synchronously rotating the workpiece 12 relative to the grinding tool 14 based on the first and second signals. In other words, the synchronization signal generation unit 92 obtains the phase difference (pulse difference) between the first signal output from the first encoder 68 and the second signal output from the second encoder 70, and generates a synchronization signal that minimizes this phase difference. The process then moves to step S22.

[0045] In step S22, a command signal generation step is performed. In this step, the command signal generation unit 96 generates a command signal based on a predetermined cancel signal and a synchronization signal. The cancel signal is used to suppress fluctuations in the rotational speed of the workpiece 12 caused by cogging of the first motor 40 that rotates the workpiece 12. In other words, the command signal generation unit 96 generates a command signal based on the cancel signal determined in the cancel signal determination step and the synchronization signal generated in the synchronization signal generation step. The process then moves to step S23.

[0046] In step S23, a signal output step is performed. In this step, the signal output unit 98 outputs the command signal generated by the command signal generating unit 96 to control the first motor 40. In other words, the signal output unit 98 outputs the command signal to the first servo amplifier 74. The first servo amplifier 74 controls the rotational speed of the first motor 40 based on the command signal output from the signal output unit 98. In this case, since the command signal is generated based on the synchronization signal and the cancel signal, it is possible to suppress fluctuations in the rotational speed caused by cogging of the first motor 40 when the workpiece 12 rotates.

[0047] Thus, the workpiece tooth surface 62 of the workpiece 12 can be ground with high precision using the grinding tooth surface 66 of the grinding tool 14. In this embodiment, the workpiece tooth surface 62 is ground over the entire circumference of the workpiece 12. After the grinding step is completed, the finished gear obtained by grinding the workpiece 12 is removed from the gear mounting shaft 38. The process then proceeds to step S3.

[0048] In step S3, the determination unit 100 determines whether grinding of all workpieces 12 has been completed. If the determination unit 100 determines that grinding of all workpieces 12 has not been completed (No in step S3), the determination unit 100 determines whether the grinding conditions have been changed. Here, the grinding conditions refer to the size and shape of the workpiece 12, the rotation speed of the workpiece 12 during the grinding step, the size and shape of the grinding tool 14, and the rotation speed of the grinding tool 14 during the grinding step.

[0049] If the determination unit 100 determines that the grinding conditions have not changed (No in step S4), the workpiece 12 is mounted on the gear mounting shaft 38 and then the process proceeds to step S2. In other words, in this case, the cancel signal determination step is not performed. This is because, without changing the grinding conditions, the workpiece 12 can be ground with high precision using the already determined cancel signal.

[0050] If the determination unit 100 determines that the grinding conditions have changed (YES in step S4), for example, a workpiece having a different shape than the workpiece 12 previously ground may be mounted on the gear mounting shaft 38. Alternatively, the grinding tool 14 may be replaced depending on the situation. The process then proceeds to step S1. Specifically, in this case, a cancel signal determination step is performed to determine a new cancel signal corresponding to the current grinding conditions.

[0051] When the determination unit 100 determines that the grinding of all the workpieces 12 has been completed (Yes in step S3), the grinding process is completed. Figure 3 The processing shown.

[0052] According to this embodiment, the first motor 40 is controlled by a command signal generated based on the cancel signal and the synchronization signal. Consequently, fluctuations in the rotational speed of the workpiece 12 caused by cogging of the first motor 40 during grinding of the workpiece tooth surface 62 can be suppressed. This reduces grinding errors in the workpiece tooth surface 62, thereby suppressing noise generated during use of the product gear obtained by grinding the workpiece tooth surface 62. Consequently, a more advanced grinding system 10 and a method for controlling the grinding system 10 can be provided.

[0053] In the above embodiment, an example is described in which the workpiece 12 serves as the first rotating body 106 and the grinding tool 14 serves as the second rotating body 108. The present invention is not limited to this example; for example, the grinding tool 14 may serve as the first rotating body 106 and the workpiece 12 may serve as the second rotating body 108. In this case, in the cancel signal determination step, the cancel signal determination unit 94 adjusts the phase and amplitude of a candidate signal serving as a cancel signal while the grinding tool 14 and the workpiece 12 are rotating without engaging with each other, and determines the candidate signal that minimizes the variation in the rotational speed of the grinding tool 14 due to cogging as the cancel signal. Furthermore, in the synchronization signal generation step, the synchronization signal generation unit 92 generates a synchronization signal for synchronously rotating the grinding tool 14 relative to the workpiece 12 based on the first and second signals. Furthermore, in the command signal generating step, the command signal generating unit 96 generates a command signal based on a predetermined cancel signal and a synchronization signal. The cancel signal is used to suppress fluctuations in the rotational speed of the grinding tool 14 caused by cogging of the second motor 58 that rotates the grinding tool 14. Furthermore, in the signal outputting step, the signal outputting unit 98 outputs the command signal generated by the command signal generating unit 96 to control the second motor 58.

[0054] The following supplementary notes are also disclosed regarding the above-mentioned embodiment.

[0055] (Note 1) The grinding system (10) of the present invention grinds the workpiece tooth surface (62) of the workpiece by making a gear-shaped workpiece (12) mesh with a grinding tool (14) and rotate the workpiece using the spiral grinding tooth surface (66) of the grinding tool, wherein one of the workpiece and the grinding tool is a first rotating body (106), and the other of the workpiece and the grinding tool is a second rotating body (108), and the grinding system has a signal acquisition unit (90), a synchronization signal generation unit (92), an instruction signal generation unit (96) and a signal output unit (98), wherein the signal acquisition unit acquires a signal indicating the rotation speed of the first rotating body. and a second signal indicating the rotational speed of the second rotating body; the synchronization signal generating unit generates a synchronization signal for causing the first rotating body to rotate synchronously with respect to the second rotating body based on the first signal and the second signal; the instruction signal generating unit generates an instruction signal based on a predetermined cancellation signal and the synchronization signal, the cancellation signal being used to suppress the change in the rotational speed of the first rotating body caused by the cogging effect of the motor (40, 58) that rotates the first rotating body; the signal output unit (98) outputs the instruction signal generated by the instruction signal generating unit to control the motor.

[0056] With this configuration, the motor that rotates the first rotating body is controlled by a command signal generated based on the cancel signal and the synchronization signal. This reduces fluctuations in the rotational speed of the first rotating body caused by cogging in the motor during grinding of workpiece tooth surfaces. This reduces grinding errors on the workpiece tooth surfaces, thereby suppressing noise generated when using the finished gear obtained by grinding the workpiece tooth surfaces. Consequently, a more advanced grinding system can be provided.

[0057] (Note 2) In the grinding system described in Note 1, it is possible that there is also a cancellation signal determination unit (94), which adjusts the amplitude and phase of a candidate signal that is a candidate for the cancellation signal when the first rotating body and the second rotating body are rotating without engaging with each other, and determines the candidate signal with the smallest change in the rotation speed of the first rotating body caused by the tooth effect as the cancellation signal.

[0058] According to such a configuration, the cancel signal can be easily determined.

[0059] (Note 3) In the grinding system according to Supplementary Note 2, the candidate signal may be a sine wave having a frequency corresponding to a frequency of a rotational speed variation of the first rotating body caused by the cogging.

[0060] According to such a configuration, the fluctuation in the rotation speed of the first rotating body due to the cogging can be further reduced.

[0061] (Note 4) In the grinding system described in Note 2 or 3, the cancellation signal determination unit may include a phase search unit (102) and an amplitude search unit (104), wherein the phase search unit changes the phase of the candidate signal while rotating the first rotating body while keeping the amplitude of the candidate signal constant, thereby searching for the optimal phase of the candidate signal with the minimum change amount; and the amplitude search unit changes the amplitude of the candidate signal while rotating the first rotating body while keeping the phase of the candidate signal at the optimal phase, thereby searching for the optimal amplitude of the candidate signal with the minimum change amount.

[0062] According to such a configuration, it is possible to efficiently find a candidate signal in which the amount of change in the rotational speed of the first rotating body due to the cogging is minimized.

[0063] (Note 5) In the grinding system according to any one of Supplementary Notes 1 to 4, the first rotating body may be the workpiece, and the second rotating body may be the grinding tool.

[0064] According to such a configuration, it is possible to suppress fluctuations in the rotation speed of the workpiece caused by cogging of the motor that rotates the workpiece.

[0065] (Note 6) In the control method of the grinding system of the present invention, the grinding system grinds the workpiece tooth surface of the workpiece with the spiral grinding tooth surface of the grinding tool by meshing and rotating the gear-shaped workpiece and the grinding tool, one of the workpiece and the grinding tool is a first rotating body, and the other of the workpiece and the grinding tool is a second rotating body. The control method of the grinding system includes a signal acquisition step, a synchronization signal generation step, an instruction signal generation step and a signal output step, wherein, in the signal acquisition step, a first signal indicating the rotation speed of the first rotating body and a signal indicating the rotation speed of the second rotating body are acquired. a second signal indicating the rotational speed of the second rotating body; in the synchronization signal generating step, a synchronization signal for causing the first rotating body to rotate synchronously with the second rotating body is generated based on the first signal and the second signal; in the command signal generating step, a command signal is generated based on a predetermined cancellation signal and the synchronization signal, the cancellation signal being used to suppress changes in the rotational speed of the first rotating body caused by the cogging effect of the motor that causes the first rotating body to rotate; and in the signal output step, the command signal generated by the command signal generating step is output to control the motor.

[0066] According to such a method, since the same effects as those in Supplementary Note 1 are achieved, a more excellent method for controlling a grinding system can be provided.

[0067] (Note 7) In the control method of the grinding system described in Appendix 6, it may be that there is also a cancellation signal determination step. In this cancellation signal determination step, the amplitude and phase of the candidate signal that becomes the candidate of the cancellation signal are adjusted in a state where the first rotating body and the second rotating body are rotating without engaging with each other, and the candidate signal with the smallest change in the rotation speed of the first rotating body caused by the cogging effect is determined as the cancellation signal.

[0068] According to this method, the same effect as Supplementary Note 2 is achieved.

[0069] (Note 8) In the control method of the grinding system according to Supplementary Note 7, the candidate signal may be a sine wave having a frequency corresponding to a frequency of a rotational speed variation of the first rotating body caused by the cogging.

[0070] According to such a structure, the same effect as Supplementary Note 3 is achieved.

[0071] (Note 9) In the control method of the grinding system described in Note 7 or 8, the cancellation signal determination step may include a phase search step and an amplitude search step, wherein, in the phase search step, the phase of the candidate signal is changed while the first rotating body is rotated while the amplitude of the candidate signal is kept constant, thereby searching for the optimal phase of the candidate signal with the minimum change amount; and in the amplitude search step, the amplitude of the candidate signal is changed while the first rotating body is rotated while the phase of the candidate signal is kept at the optimal phase, thereby searching for the optimal amplitude of the candidate signal with the minimum change amount.

[0072] According to such a method, the same effect as that of Supplementary Note 4 can be achieved.

[0073] (Note 10) In the method for controlling a grinding system according to any one of Supplementary Notes 6 to 9, the first rotating body may be the workpiece, and the second rotating body may be the grinding tool.

[0074] According to this method, the same effect as Supplementary Note 5 is achieved.

[0075] Although the present invention has been described in detail, the present invention is not limited to the above-mentioned embodiments. These embodiments can be variously added, replaced, changed, partially deleted, etc. without departing from the scope of the main purpose of the present invention, or without departing from the scope of the main purpose of the present invention derived from the contents recorded in the technical solution and its equivalents. In addition, these embodiments can also be implemented in combination. For example, in the above-mentioned embodiment, the order of each action and the order of each processing are shown as an example and are not limited to this. In addition, the same applies to the case where numerical values ​​or formulas are used in the description of the above-mentioned embodiment.

Claims

1. A grinding system that grinds a gear-shaped workpiece and a grinding tool by meshing and rotating the workpiece and grinding the workpiece tooth surface with a helical grinding tooth surface of the grinding tool. It is characterized in that One of the workpiece and the grinding tool is a first rotating body, The other of the workpiece and the grinding tool is a second rotating body, The grinding system comprises a signal acquisition unit, a synchronization signal generation unit, a command signal generation unit and a signal output unit, wherein: The signal acquisition unit acquires a first signal indicating a rotational speed of the first rotating body and a second signal indicating a rotational speed of the second rotating body; The synchronization signal generating unit generates a synchronization signal for causing the first rotating body to rotate synchronously with the second rotating body based on the first signal and the second signal; the command signal generating unit generates a command signal based on a predetermined cancel signal and the synchronization signal, wherein the cancel signal is used to suppress a rotation speed variation of the first rotating body caused by a cogging effect of a motor that rotates the first rotating body; The signal output unit outputs the command signal generated by the command signal generation unit to control the motor.

2. The grinding system according to claim 1, characterized in that It also has a cancellation signal determination unit. When the first rotating body and the second rotating body rotate without engaging with each other, the cancellation signal determination unit adjusts the phase and amplitude of a candidate signal that is a candidate for the cancellation signal, and determines the candidate signal with the smallest rotation speed change of the first rotating body caused by the cogging effect as the cancellation signal.

3. The grinding system according to claim 2, characterized in that The candidate signal is a sine wave having a frequency corresponding to a frequency of a rotation speed fluctuation of the first rotating body caused by the cogging.

4. The grinding system according to claim 2, characterized in that The cancellation signal determination unit includes a phase search unit and an amplitude search unit, wherein: The phase search unit rotates the first rotating body while changing the phase of the candidate signal while keeping the amplitude of the candidate signal constant, thereby searching for an optimal phase of the candidate signal with the minimum amount of change; The amplitude search unit rotates the first rotating body while changing the amplitude of the candidate signal while maintaining the phase of the candidate signal at the optimal phase, thereby searching for the optimal amplitude of the candidate signal that minimizes the amount of change.

5. The grinding system according to any one of claims 1 to 4, characterized in that The first rotating body is the workpiece, The second rotating body is the grinding tool.

6. A method for controlling a grinding system, wherein the grinding system grinds a tooth surface of a gear-shaped workpiece with a grinding tool by meshing and rotating the workpiece with the helical grinding tooth surface of the grinding tool. It is characterized in that One of the workpiece and the grinding tool is a first rotating body, The other of the workpiece and the grinding tool is a second rotating body, The control method of the grinding system comprises a signal acquisition step, a synchronization signal generation step, a command signal generation step and a signal output step, wherein: In the signal acquisition step, a first signal indicating the rotational speed of the first rotating body and a second signal indicating the rotational speed of the second rotating body are acquired; In the synchronization signal generating step, a synchronization signal for causing the first rotating body to rotate synchronously with the second rotating body is generated based on the first signal and the second signal; In the command signal generating step, the command signal is generated based on a predetermined cancellation signal and the synchronization signal, the cancellation signal being used to suppress a rotation speed variation of the first rotating body caused by a cogging effect of a motor that rotates the first rotating body; In the signal output step, the command signal generated in the command signal generation step is output to control the motor.

7. The control method of the grinding system according to claim 6, characterized in that: There is also a cancellation signal determination step, in which the phase and amplitude of a candidate signal that is a candidate for the cancellation signal are adjusted in a state in which the first rotating body and the second rotating body rotate without engaging with each other, and the candidate signal with the smallest rotational speed change of the first rotating body caused by the cogging effect is determined as the cancellation signal.

8. The control method of the grinding system according to claim 7, characterized in that: The candidate signal is a sinusoidal wave having a frequency corresponding to a frequency of a rotation speed fluctuation of the first rotating body caused by the cogging.

9. The control method of the grinding system according to claim 7, characterized in that: The cancellation signal determination step includes a phase search step and an amplitude search step, wherein: In the phase search step, the first rotating body is rotated while the phase of the candidate signal is changed while the amplitude of the candidate signal is kept constant, thereby searching for an optimal phase of the candidate signal with the minimum variation. In the amplitude search step, the first rotating body is rotated while changing the amplitude of the candidate signal while maintaining the phase of the candidate signal at the optimal phase, thereby searching for the optimal amplitude of the candidate signal that minimizes the variation.

10. The method for controlling a grinding system according to any one of claims 6 to 9, characterized in that: The first rotating body is the workpiece, The second rotating body is the grinding tool.

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