Groove polishing method, groove polishing device, and storage medium

Abstract

The present application provides a groove grinding method, a groove grinding device and a storage medium, which inhibit the generation of ungrounded portions after grinding. The groove grinding method is a groove grinding method in which a plurality of grooves provided at a prescribed angular interval on an outer peripheral surface of a shaft are sequentially ground by a grinding wheel, wherein all of the plurality of grooves are ground by a machining process including a control process, the control process including: a control process of determining a position or a region on the outer periphery where a maximum point or a minimum point of vibration of the shaft centeredly aligned exists; a control process of taking a groove existing in the position or the region among the plurality of grooves as a first grinding machining groove on which initial grinding machining is performed, and performing grinding machining on the first grinding machining groove on the basis of aligning the center of the first grinding machining groove with the center of the grinding wheel; and thereafter, a control process of rotating the shaft by a prescribed angular interval with respect to the remaining grooves among the plurality of grooves and performing grinding machining.

Description

Technical Field

[0001] This invention relates to a groove grinding method, a groove grinding apparatus, and a storage medium. Background Technology

[0002] Patent Document 1 discloses a groove grinding machine that uses a high-speed rotating grinding wheel to grind (peel) grooves on a workpiece held by an indexing unit and a center tailstock. After grinding one groove, the groove grinding machine rotates the workpiece 120° via the indexing unit so that the next groove faces the grinding wheel.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 9-136254 (see, for example, reference) Figure 5 Paragraph 0015)

[0006] The problem to be solved by the present invention

[0007] When grinding the grooves of the shaft, the shaft, which is aligned with the center, vibrates. As a result, the position of the groove, which is indexed by rotating the shaft, shifts due to the vibration of the shaft. Consequently, there is no grinding allowance at the edge of the groove, and unground portions may remain. Summary of the Invention

[0008] The present invention was made in view of the problem that aims to suppress the generation of unground portions after grinding.

[0009] One aspect of the present invention is a groove grinding method that uses a grinding wheel to sequentially grind a plurality of grooves arranged at predetermined angular intervals on the outer circumferential surface of a shaft. The method involves grinding all of the plurality of grooves through a processing step including the following control steps: a control step that determines the position or region on the outer circumference where the maximum or minimum vibration point of the shaft, which is centered and aligned, exists; a control step that uses the groove present at the stated position or region as the first grinding groove for initial grinding, and grinds the first grinding groove while aligning its center with the center of the grinding wheel; and a control step that subsequently rotates the shaft sequentially relative to the remaining grooves of the plurality of grooves at the predetermined angular intervals and grinds them.

[0010] According to another aspect of the present invention, a groove grinding apparatus and a storage medium corresponding to the above-described groove grinding method are provided.

[0011] Invention Effects

[0012] According to these methods, by setting the first grinding groove as described above, it is possible to suppress the displacement of the groove position caused by shaft vibration when indexing the position of the remaining grooves. As a result, it is possible to make it difficult for unground portions to be generated in the entire set of multiple grooves, and to suppress the generation of unground portions remaining after grinding. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the main components of the grinding device viewed from above.

[0014] Figure 2 This is a schematic diagram of the main components of the groove grinding device viewed from the side.

[0015] Figure 3 This is a diagram illustrating the slot detection position of the sensor.

[0016] Figure 4 This is a diagram illustrating the vibration measurement location of the sensor.

[0017] Figure 5 It is an explanatory diagram of the control process that constitutes the processing steps.

[0018] Figure 6 This is the first diagram illustrating the method for determining vibration in the vibration determination process.

[0019] Figure 7 This is the second diagram illustrating the method for determining vibration in the vibration determination process.

[0020] Figure 8 This is an explanatory diagram of the first and second grinding processes.

[0021] Figure 9 This is a flowchart of an example of process control.

[0022] Figure 10A This is the first diagram illustrating the verification results.

[0023] Figure 10B This is the second diagram illustrating the verification results.

[0024] Figure 10C This is the third diagram illustrating the verification results.

[0025] Figure 11 This diagram illustrates the three scenarios used in further verification.

[0026] Figure 12 This is a graph representing the verification results for the first scenario.

[0027] Figure 13 This is a graph representing the verification results for the second scenario.

[0028] Figure 14 This is a graph representing the verification results for the third scenario.

[0029] Symbol Explanation

[0030] Unit 10

[0031] 20 Second Unit

[0032] 21 rotating axes

[0033] 23 Grinding Wheel

[0034] 31 sensors

[0035] 50 controllers

[0036] G slot

[0037] PC1 center alignment process

[0038] PC2 vibration determination process

[0039] PC3 First Grinding Process

[0040] PC4 Second Grinding Process

[0041] R region (multiple regions)

[0042] Rmax first region (a defined region, the area where the maximum vibration of the shaft exists)

[0043] Rmin second region (a defined region, the region where the minimum point of shaft vibration exists)

[0044] The center of the first grinding groove of Y1

[0045] Y2 grinding wheel center

[0046] W workpiece (shaft)

[0047] 100-slot grinding device Detailed Implementation

[0048] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0049] Figure 1 This is a schematic diagram of the main components of the groove grinding device 100 as viewed from above. Figure 2This is a schematic diagram of the main components of the groove grinding apparatus 100, viewed from the side. The Z-direction in the diagram corresponds to the vertical direction. The groove grinding apparatus 100 has a grinding wheel 23, which sequentially grinds a plurality of grooves G arranged at predetermined angular intervals on the outer peripheral surface of a workpiece W. The workpiece W is a shaft, for example, a fixed pulley of a continuously variable transmission. Here, the number of grooves G is 3, and in this case, the predetermined angular interval is 120°. When the number of grooves G is set to N, the predetermined angular interval is 360 / N. Figure 2 The image shows a representative example of the groove G facing the grinding wheel 23 among multiple grooves G.

[0050] Multiple grooves G extend along the axial direction of the workpiece W. Each groove G has an arc-shaped cross-section and forms retaining grooves for the balls (rollers) forming a ball bearing structure within a fixed pulley. Each groove G is rough-machined, for example, in a forging process, and after heat treatment by carburizing, is finished by grinding in a groove grinding apparatus 100. Therefore, the workpiece W is provided in the groove grinding apparatus 100 in the state before each of the multiple grooves G is ground.

[0051] The groove grinding apparatus 100 includes a first unit 10, a second unit 20, a sensor unit 30, and a controller 50. The first unit 10 is a workpiece-side unit that pushes the workpiece W along the axial direction to center it (align) and rotates the workpiece W. The first unit 10 includes an indexing unit 11 and a center unit 12.

[0052] The indexing section 11 includes a fixed center 111, a motor 112, and a holding section 113. The fixed center 111 is used for center alignment of the workpiece W. The fixed center 111 is inserted into a center hole provided at one end of the workpiece W. The motor 112 rotates the workpiece W. The motor 112 can rotate the workpiece W at certain angular intervals, thereby indexing the rotational position of the workpiece W, such as the groove position. In the groove position indexing, the workpiece W is positioned at 120° intervals, i.e., at each predetermined angular interval, and groove G grinding is performed each time. The holding section 113 clamps (holds) the workpiece W at one end. While clamped by the holding section 113, the workpiece W rotates via the holding section 113 and the motor 112.

[0053] The center portion 12 has a tail center 121 and a moving mechanism 122. The tail center 121, together with the fixed center 111, performs center alignment of the workpiece W. The tail center 121 is inserted into a center hole provided at the other end of the workpiece W. The tail center 121 is disposed in the moving mechanism 122. The moving mechanism 122 is configured to be movable along the axial direction (X direction shown in the figure) of the first unit portion 10. By moving the moving mechanism 122 towards the workpiece W along the axial direction of the first unit portion 10, the tail center 121 pushes the workpiece W along the axial direction of the first unit portion 10, and together with the fixed center 111, performs center alignment (centering) of the workpiece W.

[0054] The second unit 20 is a tool-side unit, comprising a rotating shaft 21, a moving mechanism 22, and a grinding wheel 23. The rotating shaft 21 is configured to be orthogonal to the axis of the first unit 10. The axis of the rotating shaft 21 constitutes the axis of the second unit 20 and corresponds to the Y direction shown in the figure. Therefore, the axes of the first unit 10 and the second unit 20 are orthogonal to each other. The rotating shaft 21 is provided in the moving mechanism 22.

[0055] The moving mechanism 22 includes a motor 221 that rotates the rotating shaft 21. The moving mechanism 22 is configured to move along the axial direction of the first unit 10, the axial direction of the second unit 20, and in directions orthogonal to these axial directions, namely the X, Y, and Z directions shown in the figure. When the moving mechanism 22 moves, the rotating shaft 21 and the motor 221 also move together.

[0056] A grinding wheel 23 is mounted on a rotating shaft 21. The grinding wheel 23 is fixed to the front end of the rotating shaft 21. The grinding wheel 23 has a disc-shaped shape and is concentrically arranged relative to the rotating shaft 21. The grinding wheel 23 rotates integrally with the rotating shaft 21, grinding multiple grooves G. The grinding wheel 23 has an outer peripheral portion 231 with a circular arc cross-section, which is used to grind multiple grooves G.

[0057] The second unit 20, configured in this way, together with the first unit 10, uses a grinding wheel 23 to grind multiple grooves G in sequence. In other words, the first unit 10 and the second unit 20 cooperate to grind multiple grooves G in sequence.

[0058] The sensor unit 30 includes a sensor 31 and a moving mechanism 32. The sensor 31 is disposed on the outer periphery of the workpiece W. The sensor 31 is a proximity sensor, which is switched on and off depending on its proximity to or separation from the workpiece W. The sensor 31 is mounted on the moving mechanism 32 and moves together with it. The moving mechanism 32 is configured to move in both the X and Z directions as shown in the figure, and the sensor 31 is configured to face the workpiece W from the Z direction. Therefore, the sensor 31 can move directly above the workpiece W along its extension direction and can approach and separate from the workpiece W. Figure 2This indicates that sensor 31 is in the standby position.

[0059] Sensor 31 is used for detecting the groove G and measuring the vibration of the workpiece W. The vibration of the workpiece W is the vibration of the outer diameter of the workpiece W, which is the vibration in the radial direction of the workpiece W (positive when measured in the direction of increasing radius, and negative when measured in the direction of decreasing radius). Sensor 31 is configured in these cases as described below.

[0060] Figure 3 This is a diagram illustrating the slot detection position of sensor 31. Figure 4 This diagram illustrates the vibration measurement position of sensor 31. Upon detecting a groove G, sensor 31 moves, for example, from a standby position along the axial direction of the first unit 10 towards the fixed center 111, to an axial position that radially overlaps with the plurality of grooves G. This axial position is the groove detection position. At the groove detection position, sensor 31 further approaches the workpiece W until the radial position of the groove G can be detected. The groove G can be detected by detecting the state of sensor 31 from on to off based on the signal from sensor 31.

[0061] The groove G is detected by the sensor 31, for example, as a reference groove that serves as a reference for the circumferential position on the workpiece W. The groove G detected as a reference groove is used as a reference for the circumferential position on the workpiece W for vibration measurement of the workpiece W. Any one of the multiple grooves G is used as a reference groove for detection because by detecting any one of the multiple grooves G that can be detected by the sensor 31 and using it as a reference, it is easy to correspond the vibration measurement position (measurement point) on the circumferential direction of the workpiece W to the respective groove positions of the multiple grooves G.

[0062] In contrast, to determine the relationship between the rotational position and the circumferential position of the workpiece W, detection and setting can be performed using any circumferential position as a reference when the sensor 31 faces any position on the workpiece W. Even in this case, as long as any one of the multiple grooves G is detected after setting the reference, the positional relationship between the detected groove G and the reference can be determined, thus allowing the measurement point to correspond to the groove positions of multiple grooves G. However, unlike reference setting, detecting the groove G requires a corresponding amount of time in this case.

[0063] During vibration measurement, sensor 31 moves from the groove detection position to an axial position that does not overlap radially with the multiple grooves G, and the workpiece W has a circular cross-section. This axial position is the vibration measurement position. At the vibration measurement position, sensor 31 gradually approaches the workpiece W from its disconnected position, storing the Z-direction position when sensor 31 is on. As a result, the outer diameter of workpiece W is measured at the circumferential position corresponding to the reference groove. Then, using the circumferential position corresponding to the reference groove as the measurement start point, workpiece W is rotated at 60° intervals via the first unit 10, and the outer diameter position is measured each time, thereby measuring the outer diameter position of workpiece W at 6 locations. Since the outer diameter position of workpiece W is indicated by the vibration of workpiece W, the vibration of workpiece W is thus measured at a total of 6 locations.

[0064] Rotating at 60° intervals is equivalent to rotating at 180 / N degree intervals when the number of slots G is N. Furthermore, measuring at 6 positions is equivalent to measuring at 2N positions when the number of slots G is N. By setting the initial measurement start point among the multiple measurement points at a circumferential position corresponding to the reference slot, the measurement points can be aligned with the individual slot positions of the multiple slots G. Alternatively, the measurement start point can be set at other circumferential positions.

[0065] Return to Figure 1 and Figure 2 The controller 50 comprises one or more computers (microcomputers) equipped with a central processing unit (CPU), read-only memory (ROM), random access memory (RAM), and input / output interface (I / O interface). The controller 50 is controlled by the CPU executing a program stored in the ROM or RAM. The program can also be a program stored on a non-disposable storage medium such as a CD-ROM.

[0066] The controller 50 controls the first unit 10, the second unit 20, and the sensor unit 30. In the first unit 10, the motor 112, the gripping part 113, and the moving mechanism 122 are controlled by the controller 50. In the second unit 20, the moving mechanism 22 and the motor 221 are controlled by the controller 50, and in the sensor unit 30, the moving mechanism 32 is controlled by the controller 50. For example, a signal from the sensor 31 is input to the controller 50. Other signals required for machining control can be appropriately input to the controller 50.

[0067] The controller 50, based on a stored program, executes machining control to form a machining process consisting of multiple control steps, thereby grinding all of the multiple grooves G of the workpiece W. This machining control is executed based on the machining program. In other words, the program stored in the controller 50 causes the controller 50 to perform control over grinding all of the multiple grooves G of the workpiece W through the machining program. The machining process consists of multiple control steps as described below.

[0068] Figure 5 It is an explanatory diagram of the control processes that constitute the processing steps. For example... Figure 5 As shown, the machining process is roughly divided into four control processes: center alignment (centering) process PC1, vibration determination process PC2, first grinding process PC3, and second grinding process PC4. Center alignment process PC1 is a process in which the workpiece W is centered by pushing the center point along the axial direction using the first unit 10. The vibration determination process PC2 follows center alignment process PC1.

[0069] Vibration determination step PC2 is a process of determining the position or region R on the outer periphery of the center-aligned workpiece W where the maximum or minimum vibration point is located. In other words, vibration determination step PC2 is a process of determining the maximum or minimum vibration point of the center-aligned workpiece W based on the position or region R on the outer periphery. In determining the region R, the maximum or minimum vibration point is determined to exist within that region R. In addition to the detection of the reference groove and the vibration measurement of the workpiece W described above, vibration determination step PC2 also includes the determination of vibration as described below.

[0070] Figure 6 , Figure 7 This is an explanatory diagram of the vibration determination method in vibration determination process PC2. Figure 6 This indicates that there is a slot G in the first region Rmax. Figure 7 This indicates the case where groove G exists in the second region Rmin. The first region Rmax is the region R on the outer periphery where the maximum vibration point exists, and the second region Rmin is the region R on the outer periphery where the minimum vibration point exists. The workpiece center P1 represents the center of workpiece W.

[0071] like Figure 6 , Figure 7 As shown, in the vibration determination process PC2, the outer periphery of the workpiece W is divided into multiple regions R. These regions R are set to be equally spaced, and with a total of 6 measurement points, 6 regions R are set at 60° intervals. That is, the number of regions R is set to the same as the number of measurement points. Therefore, each of the multiple regions R must contain one measurement point. The multiple regions R can be set such that any groove G in each of the multiple regions R is located circumferentially towards the center, thus allowing for balanced setting of regions R relative to each groove G. If the number of grooves G is set to N, then with the first region Rmax or the second region Rmin as the defined region, multiple regions R at 180 / N degree intervals, including this defined region, are set for the workpiece W.

[0072] Figure 6The first region Rmax shown is determined based on the measurement point with the greatest vibration. That is, the region R containing the measurement point with the greatest vibration among multiple measurement points is defined as the first region Rmax. The measurement point with the greatest vibration can be determined by comparing the vibrations measured at a total of six locations. Therefore, the first region Rmax is determined based on the comparison of vibrations measured at a total of six locations.

[0073] Figure 7 The second region Rmin shown is located opposite the first region Rmax relative to the workpiece center P1, and is symmetrical to the first region Rmax. Therefore, the second region Rmin is indirectly determined by determining the first region Rmax. In other words, determining one of the first region Rmax or the second region Rmin also determines the other. In this sense, the vibration determination process PC2 can also be described as the process of determining the region R on the outer periphery where the maximum or minimum vibration point exists.

[0074] The first region Rmax is determined to identify the first grinding groove among multiple grooves G where grinding initially takes place. For example... Figure 6 As shown, when groove G exists in the first region Rmax, groove G in the first region Rmax is used as the first grinding groove. On the other hand, when groove G does not exist in the first region Rmax, as... Figure 7 As shown, the groove G in the second region Rmin is used as the first grinding groove.

[0075] The setting of the first grinding chamber as described above can be considered as part of the control of the first grinding chamber used in the grinding process. Therefore, the setting of the first grinding chamber is controlled as part of the control of the first grinding step PC3 described below. Figure 5 As shown, the vibration determination process PC2 is followed by the first grinding process PC3, and then the second grinding process PC4. The first grinding process PC3 and the second grinding process PC4 are explained below.

[0076] Figure 8 This is an explanatory diagram of the first grinding process PC3 and the second grinding process PC4. The first grinding process PC3 is a process in which the groove G that exists in the first region Rmax or the second region Rmin among the multiple grooves G is used as the first grinding processing groove, and the first grinding processing groove is ground on the basis of aligning the center Y1 of the first grinding processing groove with the center Y2 of the grinding wheel 23.

[0077] Therefore, in the first grinding process PC3, the detection of the first grinding groove is performed first (control A). During the detection of the first grinding groove, sensor 31 moves from the vibration detection position to the groove detection position, approaching the workpiece W. Then, while rotating the workpiece W in this state, the detection of the first grinding groove is performed based on the signal from sensor 31. At this time, the workpiece W can be rotated so that sensor 31 can detect the first grinding groove within the range of the first region Rmax (or the second region Rmin).

[0078] When the first grinding groove is detected, the center Y1 of the first grinding groove is detected (control B). The center Y1 of the first grinding groove is the center in the Y direction and is detected as follows: by moving the sensor 31 along the Y direction, the sensor 31 detects the edge portions on both sides of the first grinding groove in the circumferential direction, and calculates the center coordinates in the Y direction between the two detected edge portions based on their Y direction coordinates, thereby detecting the center Y1.

[0079] In control B, the center Y1 of the first grinding groove is further aligned with the center Y2 of the grinding wheel 23. The center Y2 of the grinding wheel 23 is also the center in the Y direction. The alignment of the center of the first grinding groove and the center of the grinding wheel 23 is achieved by moving the grinding wheel 23 along the Y direction so that the center Y2 of the grinding wheel 23 is aligned with the center Y1 of the first grinding groove.

[0080] When the center Y1 of the first grinding groove is aligned with the center Y2 of the grinding wheel 23, grinding is performed on the first grinding groove by the grinding wheel 23 (control C). The grinding of the first grinding groove is performed by moving the grinding wheel 23 from one side... Figure 2 The position of the grinding wheel 23, indicated by the double-dotted line, is moved along the X direction towards the fixed center 111 while rotating.

[0081] The second grinding step PC4 is a process in which the remaining grooves G in the multiple grooves G are sequentially ground by rotating the workpiece W at predetermined angular intervals, i.e., at 120° intervals. That is, the remaining grooves G are ground in the second grinding step PC4 after the first grinding step PC3 (control D).

[0082] The remaining groove G is the second grinding groove for the second grinding process and the third grinding groove for the third grinding process. When the grinding process in the first grinding groove is completed, the workpiece W rotates 120° to grind the second grinding groove. In addition, when the grinding process in the second grinding groove is completed, the workpiece W rotates 120° again to grind the third grinding groove.

[0083] Figure 9This is a flowchart illustrating an example of machining control performed by controller 50. In step S1, the center of workpiece W is aligned. That is, step S1 corresponds to the center alignment process PC1. Steps S2 to S4 correspond to the vibration determination step PC2. In step S2, the reference groove is detected; in step S3, the vibration of workpiece W is measured; and in step 4, the first region Rmax is determined.

[0084] Steps S5 to S9 correspond to the first grinding process PC3. In step S5, it is determined whether a groove G exists in the first region Rmax. If the determination is positive in step S5, the groove G present in the first region Rmax is designated as the first grinding groove in step S6. If the determination is negative in step S5, the groove G present in the second region Rmin is designated as the first grinding groove in step S7. After step S6 or S7, the process proceeds to step S8, where the first grinding groove is aligned with the center of the grinding wheel 23. Furthermore, grinding of the first grinding groove is performed in step S9.

[0085] Steps S10 to S13 correspond to the second grinding process PC4. In step S10, the workpiece W is rotated 120° to mark the position of the second grinding groove, and the second grinding groove is ground in step S11. Furthermore, in step S12, the workpiece W is rotated again 120° to mark the position of the third grinding groove, and the third grinding groove is ground in step S13. As a result, all of the multiple grooves G are ground.

[0086] For the second and third grinding grooves, whose groove positions are indexed by the rotation of the workpiece W, alignment with the center of the grinding wheel 23 is not performed. On the other hand, the workpiece W, which is aligned with the center, vibrates. Therefore, in the second and third grinding grooves, the indexed groove positions shift due to the vibration of the workpiece W. As a result, there is no machining allowance for grinding at the edge, and there is a concern that unground parts may remain (resulting in so-called black skin (material) residue).

[0087] In this embodiment, given the circumstances, a first region Rmax or a second region Rmin is determined in the vibration determination step PC2, and in the first grinding step PC3, the groove G present in the first region Rmax or the second region Rmin among the plurality of grooves G is used as the first grinding processing groove for grinding processing. This is based on the verification results described below.

[0088] Figures 10A to 10C This is an explanatory diagram of the verification results. In Figures 10A to 10C In the diagram, multiple grooves G, namely groove G1, groove G2, and groove G3, are schematically represented by circles. The diagram also indicates the case where groove G1 is located at the point of maximum vibration, i.e., groove G1 exists within the first region Rmax. Figures 10A to 10C In the diagram, the horizontal direction corresponds to the Y-direction, and the vertical direction corresponds to the Z-direction. This also applies to the following description. Figures 11-14 .

[0089] Figure 10A This indicates the grinding process starting from groove G1. Figure 10B This indicates the grinding process starting from groove G2. Figure 10C This indicates the grinding process starting from groove G3. Therefore, from... Figure 6 It can be seen that, Figure 10B , Figure 10C This indicates the case where the groove G, which does not exist in the first region Rmax and the second region Rmin, is used as the first grinding groove to start the grinding process.

[0090] The first slot configuration represents the initial grinding configuration of the multiple slots G. The second slot configuration represents the grinding configuration of the multiple slots G when grinding the next slot, and the third slot configuration represents the grinding configuration of the multiple slots G when grinding the third slot. In the first slot configuration, the workpiece center P1 corresponds to the center Y1 of the first grinding slot. The workpiece center P1 also corresponds to the centers of the second and third grinding slots. The machining center P2 represents the rotation center of the workpiece W that is centered.

[0091] like Figure 10A As shown, when groove G1 is the starting groove for machining, i.e., the first grinding groove, since groove G1 is located at the point of maximum vibration, the workpiece center P1 shifts directly above the machining center P2. As a result, in the first workpiece configuration, the angle centered on the machining center P2 decreases by more than 120° α between grooves G1 and G2, and between grooves G1 and G3, and increases by more than 120° 2α between grooves G2 and G3.

[0092] In the first groove configuration, the center alignment of groove G1, which serves as the first grinding groove, and the center alignment of grinding wheel 23 are performed. During center alignment, the center Y2 of grinding wheel 23 is aligned with center Y1 in the Y direction. As a result, the center Y2 of grinding wheel 23 is located in the same Y direction position as the machining center P2. The relative positional relationship between the center Y2 of grinding wheel 23 and the machining center P2 in the Y direction does not change even if the workpiece W rotates. Therefore, in Figure 10A In the case shown, from the first slot configuration to the third slot configuration, the center Y2 of the grinding wheel 23 is located in the same Y direction position as the machining center P2.

[0093] In the second slot configuration, with the workpiece center P1 offset from the machining center P2 due to vibration, the workpiece is rotated 120° from the first slot configuration with the machining center P2 as the rotation center. In this case, the slot G2, which is the object to be machined, becomes a state where the angle on the right side of the figure is increased by "+α" (therefore, "-α" on the left side of the figure). As a result, the left edge portion of the slot G2 in the figure is offset to the lower left compared to the ideal state, and therefore, the grinding allowance at this edge portion is reduced.

[0094] In the third groove configuration, the workpiece W is rotated 120 degrees further from the second groove configuration with the machining center P2 as the rotation center. In this case, due to the relationship between groove G3 and the center Y2 of grinding wheel 23, it becomes a state where "-α" is added to the angle on the right side of the figure (therefore, "+α" on the left side of the figure) compared to the ideal state. As a result, the edge portion on the right side of groove G3 in the figure is offset to the lower right compared to the ideal state, and therefore, the grinding allowance at this edge portion is reduced.

[0095] like Figure 10B As shown, when groove G2 is the first grinding groove, the configuration of the first groove is the same as... Figure 10A The second groove configuration shown is the same. On the other hand, in the first groove configuration, the center of the first grinding groove is aligned with the center of the grinding wheel 23. Therefore, in this case, the center Y2 of the grinding wheel 23 is aligned with the center Y1 of the first grinding groove, resulting in the elimination of... Figure 10A The second groove configuration shows the offset of the groove position in the Y direction caused by the size α. On the other hand, in this case, by performing center alignment, the center Y2 of the grinding wheel 23 is offset in the Y direction towards the groove G1 side relative to the machining center P2.

[0096] In the second groove configuration, the workpiece W is rotated 120° from the first groove configuration. On the other hand, the relative positional relationship between the center Y2 of the grinding wheel 23 and the machining center P2 in the Y direction remains unchanged. Therefore, in this case, groove G2, due to its relationship with the center Y2 of the grinding wheel 23, becomes a state where the angle on the right side of the figure is increased by "-2α" (and thus "+2α" on the left side of the figure). As a result, in this case, the right edge portion of groove G3 in the figure is significantly offset to the right from the grinding wheel 23, and correspondingly, the grinding allowance becomes smaller.

[0097] Even in the third groove configuration, the relative positional relationship between the center Y2 of the grinding wheel 23 and the machining center P2 in the Y direction remains unchanged. Therefore, in this case, groove G1 also becomes a state where the angle on the right side of the figure is increased by "-α" (and thus "+α" on the left side of the figure) due to its relationship with the center Y2 of the grinding wheel 23.

[0098] like Figure 10CAs shown, when groove G3 is the first grinding groove, in the first groove configuration, the center Y2 of the grinding wheel 23 is aligned with the center Y1 of the first grinding groove. As a result, the center Y2 of the grinding wheel 23 is offset towards groove G1 in the Y direction relative to the machining center P2. Furthermore, in this case, the relative positional relationship between the center Y2 of the grinding wheel 23 and the machining center P2 in the Y direction remains unchanged in the second and third groove configurations. As a result, in the second groove configuration, due to the relationship between groove G1 and the center Y2 of the grinding wheel 23, the angle "+α" is added to the right side of the figure (therefore, "-α" is shown on the left side). Furthermore, in the third groove configuration, due to the relationship between groove G2 and the center Y2 of the grinding wheel 23, the angle "+2α" is added to the right side of the figure (therefore, "-2α" is shown on the left side).

[0099] Therefore, it can be concluded that the groove G1, located at the point of maximum vibration, is used as the first grinding groove. Figure 10A In the case shown, with Figure 10B or Figure 10C Compared to the situation shown, it is possible to suppress the positional displacement of the second or third grinding groove relative to the grinding wheel 23. Based on the above, further verification and its results will be described below.

[0100] Figure 11 This indicates three scenarios used in further verification. In further verification, the following three scenarios, where black residue is prone to occur, were tested. The first scenario is when groove G1 exists on the opposite side (and therefore the minimum point) of the point of maximum vibration. The second scenario is when groove G1 exists at the point of maximum vibration. The third scenario is when the point of maximum vibration is located on the side of groove G2 relative to groove G1, and groove G1 does not exist in either the first region Rmax or the second region Rmin.

[0101] Figures 12-14 This is a graph representing the verification results for three scenarios. Figure 12 Corresponding to the first case, Figure 13 Corresponding to the second case, Figure 14 This corresponds to the third scenario. Figures 12-14 These represent the machining allowances for each of the three grinding grooves when the first grinding groove is set as groove G1, groove G2, and groove G3, respectively.

[0102] The first grinding groove is aligned with the center of the grinding wheel 23. Therefore, the machining allowance of the first grinding groove is... Figures 12-14 In all cases shown, the left and right sides are equal as indicated by the thick box, and the grinding results are good (circular mark).

[0103] exist Figure 12In the first case shown, when groove G1, located at the point of least vibration, is used as the first grinding groove, although there is a deviation in the machining allowance between the left and right edges of grooves G2 and G3, the machining allowance is ensured (triangle mark). On the other hand, when grooves G2 and G3 are used as the first grinding grooves, a negative machining allowance may occur, meaning there may be no machining allowance (cross mark). As a result, when groove G2 is used as the first grinding groove, black residue is generated on the left edge of groove G3, and when groove G3 is used as the first grinding groove, black residue is generated on the right edge of groove G2.

[0104] exist Figure 13 In the second case shown, when the groove G1 at the location of the greatest vibration is used as the first grinding groove, and... Figure 12 The first case shown also ensures machining allowance. On the other hand, when groove G2 is used as the first grinding groove, black residue is generated on the right edge of groove G3, and when groove G3 is used as the first grinding groove, black residue is generated on the left edge of groove G2.

[0105] exist Figure 14 In the third case shown, groove G2 becomes the groove G with the minimum vibration among the multiple grooves G, and groove G3 becomes the groove G with the maximum vibration among the multiple grooves G. That is, groove G2 is a groove G that does not exist at the point of minimum vibration but exists in the second region Rmin, and groove G3 is a groove G that does not exist at the point of maximum vibration but exists in the first region Rmax. In this case, when groove G1 is used as the first grinding groove, the machining allowance of the left edge portion of groove G3 is -0.02mm.

[0106] On the other hand, when groove G2 is used as the first grinding groove, the machining allowance on the right edge of groove G1 is -0.0006mm, and when groove G3 is used as the first grinding groove, the machining allowance on the right edge of groove G1 is only -0.0001mm. As a result, when groove G2 or groove G3 is used as the first grinding groove, black residue can be ignored or contained within the range that can be removed by adjusting the grinding process.

[0107] As can be seen from the above, by using the groove G that exists in the first region Rmax or the second region Rmin as the first grinding groove, compared with using the groove G that does not exist in either the first region Rmax or the second region Rmin as the first grinding groove, the generation of black skin residue can be suppressed.

[0108] Next, the main effects of this implementation method will be explained.

[0109] (1) The groove grinding method of this embodiment is a groove grinding method that uses a grinding wheel 23 to grind multiple grooves G arranged at 120° intervals on the outer peripheral surface of the workpiece W in sequence. It grinds all of the multiple grooves G by including the following processing steps, wherein the processing steps include: determining the vibration determination step PC2 of the region R on the outer periphery where the maximum or minimum vibration point of the workpiece W, which is centered, exists; taking the grooves G in the multiple grooves G that exist in the first region Rmax or the second region Rmin as the first grinding groove for grinding processing, and grinding the first grinding groove based on aligning the center Y1 of the first grinding groove with the center Y2 of the grinding wheel 23; then, the second grinding step PC4 is to rotate the workpiece W at 120° intervals relative to the remaining grooves G in the multiple grooves G in sequence for grinding processing.

[0110] According to this method, by setting the first grinding groove as described above, it is possible to suppress the displacement of the groove position caused by the vibration of the workpiece W when indexing (calculating) the position of the remaining groove G. As a result, it is possible to reduce the likelihood of black residue forming in multiple grooves G as a whole, thus suppressing the formation of black residue.

[0111] (2) Multiple grooves G are formed on the outer circumference of the shaft at intervals of 360 / N degrees, with a groove number of N. The vibration determination process PC2 includes: rotating the workpiece W at intervals of 180 / N degrees, and measuring the vibration of the workpiece W using sensor 31 each time, thereby measuring the vibration of the workpiece W at 2N locations, and comparing the vibrations measured at the 2N locations with each other to determine the maximum or minimum point of vibration of the workpiece W among the 2N locations. When N=3, the multiple grooves G are formed at intervals of 120°. In addition, the workpiece W is rotated at intervals of 60°, and vibration is measured at a total of 6 locations.

[0112] According to this method, even without measuring the vibration of workpiece W over its entire circumference, it is possible to determine, based on the maximum or minimum vibration points of workpiece W across 2N locations, that the maximum or minimum vibration points of workpiece W over its entire circumference exist within a certain angular range. Therefore, for example, even if existing equipment lacks a sensor that measures the vibration of workpiece W over its entire circumference, it can be applied as long as a proximity sensor capable of detecting the presence or absence of slot G is available, making it highly applicable. Furthermore, compared to sensors that measure the vibration of workpiece W over its entire circumference, inexpensive proximity sensors can be used in sensor 31, which is also advantageous in terms of cost.

[0113] (3) Vibration determination step PC2 is the process of determining the first region Rmax or the second region Rmin. It involves setting multiple regions R at 180 / N degree intervals, including the first region Rmax or the second region Rmin, as a defined region for the workpiece W. The first region Rmax or the second region Rmin is determined based on the maximum or minimum vibration point of the workpiece W among 2N locations. When N=3, the multiple regions R are set at 60° intervals.

[0114] According to this method, multiple regions R each contain a measurement point. Therefore, the region R where the maximum vibration of the workpiece W exists among 2N parts can be determined as the first region Rmax, and the region R where the minimum vibration of the workpiece W exists among 2N parts can be determined as the second region Rmin.

[0115] (4) The first grinding process PC3 includes: if any one of the multiple grooves G exists in the first region Rmax, the groove G existing in the first region Rmax shall be used as the first grinding processing groove; if the first region Rmax does not contain any one of the multiple grooves G, the region R located on the opposite side of the first region Rmax relative to the workpiece center P1 shall be used as the second region Rmin, and the groove G contained in the second region Rmin shall be used as the first grinding processing groove.

[0116] According to this method, the first grinding groove can be set by determining either the first region Rmax or the second region Rmin, thus simplifying the processing control.

[0117] The embodiments of the present invention have been described above. However, the above embodiments are merely some examples of the application of the present invention and do not limit the technical scope of the present invention to the specific configurations of the above embodiments.

[0118] For example, sensor 31 can also be a sensor capable of measuring the vibration of workpiece W over its entire circumference. In this case, during the vibration determination step PC2, the maximum or minimum point of vibration of the center-aligned workpiece W can be determined, for example, based on its position on the outer circumference. Furthermore, in this case, if a groove G exists at the maximum or minimum point of vibration of workpiece W, the groove G existing at the determined position can be used as a first grinding groove for grinding.

[0119] This method can also be used to consider the maximum or minimum point of vibration of workpiece W across 2N locations as the maximum or minimum point of vibration of workpiece W over its entire circumference. In this case, the measurement point of the maximum or minimum point of vibration of workpiece W across 2N locations can be considered as the location on the outer circumference where the maximum or minimum point of vibration of workpiece W over its entire circumference exists. In this case, when the measurement point of vibration of workpiece W corresponds to the groove position of multiple grooves G, the groove G existing at a defined position can also be used as the first grinding groove for grinding.

Claims

1. A groove grinding method, comprising grinding a plurality of grooves spaced at predetermined angles on the outer circumferential surface of a shaft sequentially using a grinding wheel, characterized in that, All of the plurality of grooves are ground by a processing step including the following control steps: A control process for determining the location or region on the outer periphery where the maximum or minimum point of vibration of the shaft being centered exists; The first grinding groove is selected as the first grinding groove for initial grinding processing, and the grinding process is carried out on the basis of aligning the center of the first grinding groove with the center of the grinding wheel. Then, a control process is performed to rotate the shaft sequentially at the specified angular intervals relative to the remaining slots in the plurality of slots and to perform grinding.

2. The groove grinding method as described in claim 1, characterized in that, The plurality of grooves are formed on the outer circumference of the shaft at intervals of 360 / N degrees, with a total number of grooves N. The control process for determining the position or region includes: rotating the shaft at intervals of 180 / N degrees, and measuring the vibration of the shaft each time using a sensor disposed on the outer periphery of the shaft, thereby measuring the vibration of the shaft at 2N locations, and comparing the vibrations measured at the 2N locations with each other to determine the maximum or minimum point of the shaft's vibration among the 2N locations.

3. The groove grinding method as described in claim 2, characterized in that, The control process for determining the position or the region is the process of determining the region, which involves taking the region as a specified region, setting multiple regions at intervals of 180 / N degrees relative to the axis, including the specified region, and determining the specified region based on the maximum or minimum point of vibration of the axis between the 2N locations.

4. The groove grinding method as described in claim 3, characterized in that, The control steps for grinding the first grinding tank include: If any one of the plurality of grooves exists in the specified area and in the area where the maximum vibration of the shaft is located, i.e., the first area, the groove existing in the first area shall be used as the first grinding groove. If none of the plurality of grooves are present in the first region, the region in the plurality of regions located on the opposite side of the first region relative to the center point of the shaft is taken as the second region where the vibration of the shaft is at its minimum, and the groove present in the second region is taken as the first grinding groove.

5. A groove grinding apparatus, comprising: The first unit pushes the shaft along the axial direction to the center point for center alignment and rotates the shaft. The second unit has a rotating shaft equipped with a grinding wheel, and together with the first unit, uses the grinding wheel to grind a plurality of grooves that are spaced at predetermined angles on the outer circumferential surface of the shaft. A sensor is disposed on the outer periphery of the shaft; A controller that controls the first unit and the second unit, characterized in that, The controller performs grinding on all of the plurality of slots through processing control including the following: Based on the output of the sensor, the position or region on the outer periphery of the shaft whose vibration is maximized or minimized by the first unit portion is determined and controlled. The groove present in the location or region among the plurality of grooves is used as the first grinding groove for initial grinding. The second unit controls the grinding of the first grinding groove by aligning the center of the first grinding groove with the center of the grinding wheel. Subsequently, the first unit section rotates the shaft sequentially relative to the remaining slots in the plurality of slots at predetermined angular intervals, and the second unit section controls the grinding process.

6. A storage medium storing a computer-executable program for a groove grinding apparatus, the groove grinding apparatus utilizing a grinding wheel to sequentially grind a plurality of grooves spaced at predetermined angles on the outer circumferential surface of a shaft, characterized in that... All of the plurality of grooves are ground by a processing procedure comprising the following steps: The process of determining the location or region on the outer periphery where the maximum or minimum point of vibration of the shaft being centered exists; The process of using the groove that exists in the location or region among the plurality of grooves as the first grinding groove for initial grinding processing, and grinding the first grinding groove based on aligning the center of the first grinding groove with the center of the grinding wheel; Then, the shaft is rotated sequentially at the specified angular intervals relative to the remaining slots in the plurality of slots and then ground.

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