Processing method and processing device

Abstract

To provide a processing method and a processing device that can suppress unbalance of rotation during processing.SOLUTION: A processing method according to the present invention comprises: a preparation step at which a processing device is prepared, the processing device having a head stock that rotationally drives a work-piece around a first axis in such a manner that the work-piece can be separably fixed, a tail stock that is so made as to relatively approach and separate from the head stock in the first axis direction, and rotationally supports the work-piece in cooperation with the head stock when processing the work-piece, and a tool for processing the work-piece; a correction step at which when the work-piece is rotationally driven in the state where the work-piece is supported by the head stock and the tail stock, unbalance of rotation due to at least one of the head stock, the tail stock, and the work-piece is corrected; and a processing step at which after correction of the unbalance of rotation, the work-piece is processed by the tool.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The present invention relates to a processing method and a processing device. [Background technology]

[0002] Honing, for example, is a conventional finishing process for gears. In this process, a workpiece and a grinding wheel gear are rotated in a state of meshing with each other to perform the finishing process.

[0003] For example, Patent Document 1 describes a gear machining device for performing honing. In this device, a workpiece, or an object to be machined, is supported by being clamped from both axial ends by a work support unit consisting of a headstock and a tailstock, and an annular tool support unit having an internal gear-shaped tool disposed between the two fixtures is engaged with the workpiece. Then, by rotating the tool of the tool support unit in this state, the workpiece and the tool are rotated together to machine the workpiece. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-25149 DISCLOSURE OF THE INVENTION [Problem to be solved by the invention]

[0005] In the above-described machining, the tool and workpiece rotate, and if they are eccentric with respect to the rotation axis, a rotational imbalance occurs. As a result, significant vibrations occur during machining, which may reduce machining accuracy. Although various proposals have been made to address this rotational imbalance, there is still room for improvement. Note that this problem occurs not only in gear machining, but also in all machining methods that rotate and machine rotationally symmetrical bodies, such as cylindrical bodies.

[0006] The present invention has been made to solve the above problems, and has an object to provide a processing method and a processing device that can suppress unbalance of rotation during processing. [Means for solving the problem]

[0007] The machining method of the present invention comprises the following steps: a preparation step of preparing a machining device having a headstock that can separably fix a workpiece and rotates it about a first axis; a tailstock that can move toward and away from the headstock in the first axial direction relatively to the headstock and is configured to cooperate with the headstock to stop rotational runout of at least the workpiece when machining the workpiece; and a tool for machining the workpiece; a correction step of correcting rotational imbalance caused by at least one of the headstock, the tailstock, and the workpiece when the workpiece is supported by the headstock and the tailstock and driven to rotate; and a machining step of machining the workpiece with the tool after correcting the rotational imbalance.

[0008] In the above machining method, the correction step can include a first step of acquiring a first eccentric position when the headstock rotates independently, a second step of acquiring a second eccentric position when the tailstock rotates independently, a third step of connecting the tailstock to the workpiece supported by the headstock, a fourth step of acquiring a third eccentric position when the headstock, the tailstock, and the workpiece rotate together, a fifth step of measuring vibrations caused by the unbalance in rotation, a sixth step of temporarily separating the headstock and the tailstock if the vibrations are equal to or greater than a predetermined value, a seventh step of calculating a correction position to correct the unbalance in rotation from the first to third eccentric positions, and an eighth step of adjusting the rotational phase of the headstock and tailstock in the separated state to move the second eccentric position to the correction position.

[0009] In the above machining method, the correction step can include a first step of acquiring a first eccentric position when the headstock rotates together with the workpiece while fixing it thereto; a second step of acquiring a second eccentric position when the tailstock rotates independently; a third step of connecting the tailstock to the workpiece supported by the headstock; a fourth step of acquiring a third eccentric position when the headstock, the tailstock, and the workpiece rotate together as a unit; a fifth step of measuring vibrations caused by the unbalance in rotation; a sixth step of separating the headstock and the tailstock if the vibrations are equal to or greater than a predetermined value; a seventh step of calculating a correction position to correct the unbalance in rotation from the first to third eccentric positions; and an eighth step of adjusting the rotational phase of the headstock and tailstock in the separated state to move the second eccentric position to the correction position.

[0010] In the above processing method, an acceleration sensor and an angle sensor may be provided on each of the headstock and the tailstock, and the first to third eccentric positions may be calculated based on the acceleration of the headstock and the tailstock measured by the acceleration sensor and the rotational phase of the headstock and the tailstock measured by the angle sensor.

[0011] In the above processing method, the third to eighth steps can be repeated until the vibration measured in the fifth step becomes smaller than a predetermined value.

[0012] In the above processing method, an automatic balancer that corrects rotational imbalance is provided on at least one of the headstock and the tailstock, and the correction step can be configured to correct rotational imbalance when the headstock, the tailstock, and the workpiece rotate together using the automatic balancer.

[0013] In the above machining method, the headstock may be provided with the automatic balancer.

[0014] In the above processing method, the tailstock may be provided with the automatic balancer.

[0015] In the above processing method, the workpiece may be a gear to be processed, and the tool may be a gear-shaped tool that processes the gear to be processed by meshing with the gear to be processed at a crossing angle and driving it to rotate.

[0016] A first machining apparatus according to the present invention comprises a headstock that drives a workpiece to rotate around a first axis; a tailstock that is movable toward and away from the headstock in the first axial direction and is connected to the headstock to cooperate to stop at least rotational runout of the workpiece; a tool that machines the workpiece; a measuring device that is provided on the headstock or tailstock and that measures vibrations that occur when the workpiece is rotated while supported by the headstock and tailstock; and a control unit that, when the vibrations are equal to or greater than a predetermined value, temporarily separates the headstock and tailstock, adjusts the rotational phase of the headstock and tailstock, and then reconnects them, thereby correcting the rotational imbalance that causes the vibrations, and that starts machining of the workpiece by the tool when the vibrations become smaller than the predetermined value.

[0017] A second machining apparatus according to the present invention comprises a headstock that rotates a workpiece around a first axis, a tailstock that is spaced relatively close to the headstock in the first axis direction and is configured to stop at least rotational runout of the workpiece between the headstock and the tailstock, a tool that machines the workpiece, and an automatic balancer that is provided on at least one of the headstock and the tailstock and corrects rotational imbalance, and is configured so that the automatic balancer corrects rotational imbalance when the headstock, the tailstock, and the workpiece rotate together. [Effects of the Invention]

[0018] According to the present invention, it is possible to suppress unbalance of rotation during processing. [Brief explanation of the drawings]

[0019] [Figure 1] This is a front view showing a first embodiment in which the processing apparatus according to the present invention is applied to a gear processing apparatus. [Figure 2] This is a cross-sectional view taken along line A-A of FIG. 1. [Figure 3] This is a cross-sectional view taken along line B-B of FIG. 2. [Figure 4] This is a partially enlarged cross-sectional view of a work support unit. [Figure 5] This is a block diagram of a control unit. [Figure 6] This is a flowchart showing a gear processing method according to the first embodiment. [Figure 7] ​​​​​​​​​​​​​​​​​​​​​​​​​1 to 3, the gear machining apparatus according to this embodiment includes a base 1, a tool support unit 2 and a workpiece support unit 3 arranged thereon, and a control unit 4 that controls the driving of the apparatus. The tool support unit 2 has a support 21 and a tool housing 22 connected to the front of the support 21 and having an internal gear-shaped tool (grinding wheel) 222 attached thereto, with the axial direction of the tool 222 oriented approximately in the X-axis direction. This allows the tool 222 to mesh with the workpiece W, which is a gear to be machined.

[0022] On the other hand, the workpiece support unit 3 is made up of a headstock 31 and a tailstock 32 that support the workpiece W, and these are arranged on either side of the base 1, sandwiching the tool support unit 2. Each unit 2, 3 and the control unit 4 will be described in detail below.

[0023] <2. Tool support unit> First, the tool support unit 2 will be described in detail. As shown in Fig. 2, the support body 21 described above is provided with a shaft member 211 extending in the Y-axis direction, and a tool housing 22 is attached to the front side of this shaft member 211. Since the shaft member 211 is supported so as to be rotatable about the Y-axis, when the shaft member 211 rotates, the tool housing 22 rotates about the Y-axis. This makes it possible to impart a cross angle to the workpiece W.

[0024] Although not shown in the drawings, the support 21 is capable of reciprocating movement in the Y-axis direction on the base 1, thereby enabling the tool 222 to make cuts in the workpiece W. There are no particular limitations on the means for moving the support 21, but for example, the support 21 can be movably supported on a rail that is arranged on the base 1 and extends in the Y-axis direction, and moved along the rail by known means such as a ball screw, a nut, and a motor.

[0025] Next, the tool housing 22 will be described. As shown in FIGS. 2 and 3, the tool housing 22 includes an annular support portion 221 connected to the shaft member 211, and the support portion 221 is disposed so that its axial direction is generally oriented in the X-axis direction. An annular internal gear-shaped tool 222 is rotatably attached to the inner peripheral surface of the support portion 221 via a bearing 23. The workpiece W is machined while meshing with the tool 222 from the inside. A drive gear 223 is attached to the outer peripheral surface of the tool 222, and the drive gear 223 is rotated by a motor 224 fixed to the upper part of the support portion 235. A reducer (not shown) is provided between the motor 224 and the drive gear 223. When the motor 224 is driven, the drive gear 223 rotates together with the tool 222 at a predetermined reduction ratio. Moreover, the motor 224 is electrically connected to the control unit 4, so that the motor 224 is driven.

[0026] <3. Work support unit> Next, the workpiece support unit 3 will be described with reference to FIG. 4. FIG. 4 is an enlarged cross-sectional view of the workpiece support unit. As shown in FIGS. 1 and 3, the workpiece support unit 3 is composed of the headstock 31 and tailstock 32 described above, with the headstock 31 disposed on the left side of the tool housing 22 in the X-axis direction and the tailstock 32 disposed on the right side. The headstock 31 and tailstock 32 are spaced apart from each other in the X-axis direction and are configured to rotatably support the workpiece W. The headstock 31 is provided with a first shaft member 311 that engages with the workpiece W and extends in the X-axis direction. This first shaft member 311 is configured to rotate about the X-axis by a motor 312 built into the headstock 31.

[0027] As shown in FIG. 4 , a passage 313 extending in the X-axis direction is formed in the first shaft member 311, and a collet chuck 314 is attached to the outer peripheral surface of the tip opening of this passage 313. The collet chuck 314 is movable in the X-axis direction and expands and contracts radially as it moves in the X-axis direction. A movable part 315 of a push-pull mechanism for expanding and contracting the collet chuck 314 is inserted into this passage 313. As a result, when a workpiece W is attached to the collet chuck 314, that is, when the collet chuck 314 is inserted into the through-hole of the workpiece W, pulling the movable part 315 to the left expands the diameter of the collet chuck 314, and the workpiece W is clamped to the first shaft member 311 via the collet chuck 314. A cylindrical support 316 is fixed to the tip of the first shaft member 311 so as to surround the collet chuck 314. This support 316 comes into contact with the left surface of the workpiece W to support the workpiece W.

[0028] The headstock 31 is disposed on a first guide rail 15 that is disposed on the base 1 and extends in the X-axis direction, and moves along this first guide rail 15. A nut (not shown) is fixed to the bottom of the headstock 31, and a ball screw (not shown) is threadedly engaged with this nut. The ball screw extends in the X-axis direction and is connected to a motor (not shown) that is fixed to the base 1. Therefore, when the motor is driven, the ball screw rotates, and as a result, the headstock 31 moves in the X-axis direction.

[0029] The tailstock 32 is configured in the same manner as the headstock 31. That is, the tailstock 32 is disposed coaxially with the first shaft member 311 of the headstock 31 so as to be engageable with it, and is provided with a second shaft member 321 extending in the X direction. This second shaft member 321 is supported rotatably about the X axis and is rotated about the X axis by a motor 322 built into the tailstock 32. A recess 323 is formed at the tip of the second shaft member 321, into which the tip of the movable part 315 protruding from the first shaft member 311 fits. Furthermore, a support 324 capable of contacting the right surface of the workpiece W is attached to the tip of the second shaft member 321 so as to surround the recess 323.

[0030] The tailstock 32 is disposed on a second guide rail 16 that is disposed on the base 1 and extends in the X-axis direction, and moves along this second guide rail 16. Like the headstock 31, the tailstock 32 is also driven by a nut, ball screw, and motor (not shown) to move in the X-axis direction.

[0031] After clamping the workpiece W to the first shaft member 311, the workpiece W is rotated by the motor 312 at the rotational speed required for machining and moved to the right in the drawing. At the same time, the second shaft member 321 is also rotated synchronously by the motor 322 and moved to the left in the drawing, and the two supports 316, 324 are connected to sandwich the workpiece W at a predetermined position. This completes the workpiece support process. Note that if both the headstock 31 and the tailstock 32 are rotated in advance before the workpiece W is supported by them (by bringing the headstock 31 and the tailstock 32 close to each other while rotating), pre-machining preparation can be completed more quickly. As shown in FIG. 3, when the workpiece W is supported by the headstock 31 and the tailstock 32, the headstock 31 and the tailstock 32 move synchronously in the X-axis direction, causing the workpiece W to also move in the X-axis direction.

[0032] Furthermore, as shown in FIG. 1, the headstock 31 and the tailstock 32 are provided with acceleration sensors 5a, 5b and angle sensors 8a, 8b (not shown), and the acceleration of the inherent vibrations that occur when the headstock 31 and the tailstock 32 rotate independently, as well as the phases of the first shaft member 311 and the second shaft member 321, are measured in advance. Furthermore, during machining, the acceleration and phase of the vibrations that occur when the workpiece W is rotationally supported by the headstock 31 and the tailstock 32, as described above, are also measured using the acceleration sensors 5a, 5b and the angle sensor of either of the headstock 31 and the tailstock 32. In other words, the acceleration and phase that occur when the first shaft member 311, the second shaft member 322, and the workpiece W are rotationally driven together are also measured. The measured acceleration and phase are stored in a memory unit 42 provided in the control unit 4, as will be described later.

[0033] <4. Control Unit> Next, the control unit 4 will be described with reference to Fig. 5. As shown in Fig. 5, the control unit 4 can be configured by a PLC or a general-purpose computer having a CPU 41, RAM (not shown), and a storage unit 42, and controls various drives of the gear cutting machine. Note that this control unit 4 can also be provided separately from the control unit that drives the gear cutting machine, and can mainly only correct rotational imbalance, which will be described later.

[0034] In particular, the control unit 4 receives the acceleration and phase measured by the headstock 31 and tailstock 32 using the acceleration sensors 5a, 5b and angle sensors 8a, 8b described above, respectively, thereby correcting any imbalance that may occur when the workpiece W is rotated.

[0035] 5, the memory unit 42 of the control unit 4 stores a correction program 421 for correcting the unbalance in the rotation of the workpiece W, and this program 421 is executed by the CPU 41. Details of the correction method will be described later. In addition, the memory unit 42 stores data on the eccentric position and amount of eccentricity of the first shaft member 311 of the headstock 31 (headstock eccentricity data) 422, data on the eccentric position and amount of eccentricity of the second shaft member 321 of the tailstock 32 (tailstock eccentricity data) 423, data on the eccentric position and amount of eccentricity when the headstock 31, tailstock 32, and workpiece W are coupled (coupled eccentricity data) 424, which will be described later, acceleration data 425 measured by the acceleration sensor 5, and correction target data 426 related to the eccentric position and amount of eccentricity to be corrected by the correction.

[0036] <5. How to correct rotation imbalance> Next, a gear machining method including a method for correcting rotational imbalance will be described with reference to Fig. 6. Fig. 6 is a flowchart showing the method for correcting rotational imbalance.

[0037] First, as machine-specific information resulting from the tolerances of each component, assembly errors, etc., a first eccentric position (headstock eccentricity data) indicating the eccentric position of the first shaft member 311 of the headstock 31 and a second eccentric position (tailstock eccentricity data) indicating the eccentric position of the second shaft member 321 of the tailstock 32 are acquired in advance and stored in the memory unit 42. These eccentric positions can be acquired, for example, by a known one-plane correction method. For example, to acquire the eccentric position of the first shaft member 311, the first shaft member 311 is rotated independently, and the eccentric position is acquired by the one-plane correction method based on the vibration of the first shaft member 311 acquired by the acceleration sensor 5 and the phase acquired by the angle sensor 8. The second eccentric position and a third eccentric position, which will be described later, can also be acquired in a similar manner. In this embodiment, the amount of eccentricity is also acquired in addition to the eccentric position, but for convenience of explanation, it may be simply referred to as the eccentric position.

[0038] Next, the unbalance correction of the workpiece W performed before machining will be described with reference to FIG. 6. First, the first eccentric position and the second eccentric position stored in the memory unit 42 are read (step S1). Next, the workpiece W is fixed to the headstock 31, and the workpiece W is rotated together with the first shaft member 311 (step S2). Next, the second shaft member 321 of the tailstock 32 is rotated (step S3), and the headstock 31 and the tailstock 32 are brought close to each other, and the workpiece W is supported by both (step S4). Subsequently, the acceleration within a predetermined time is measured by an acceleration sensor of the first shaft member 311 or the second shaft member 321 (step S5). If the measured acceleration is equal to or greater than a predetermined value (NO in step S6), the rotational unbalance is corrected. At the same time, the phase is also measured by an angle sensor of the first shaft member 311 or the second shaft member 321. The third eccentric position obtained based on this phase data and the acceleration data is stored in the memory unit 42. (Step S7)

[0039] In other words, if the acceleration is equal to or greater than a predetermined value, it is possible that a non-negligible rotational imbalance may occur due to the combined eccentricities of the first shaft member 311, the second shaft member 321, and the workpiece W, which is causing vibration. Therefore, first, the headstock 31 and the tailstock 32 are separated (step S8).

[0040] Next, the control unit 4 calculates a correction target position for correcting the imbalance (step S9). This will be explained in detail below. From the measured acceleration, the acceleration peak and the rotation position at which the peak occurs can be calculated, and thereby the first to third eccentric positions can be obtained as described above.

[0041] Therefore, the control unit 4 calculates the third eccentric position and a correction target position for correcting the rotational imbalance due to the third eccentricity amount. The calculation method is outlined in Figures 7(a) to 7(e). Figure 7(a) shows the first eccentric position calculated for the headstock 31 (first shaft member 311) alone, and Figure 7(b) shows the second eccentric position calculated for the tailstock 32 (second shaft member 321) alone. Figure 7(c) shows the third eccentric position, which is a combination of the eccentric state of the workpiece W and the first and second eccentric positions. Therefore, as shown in Figure 7(d), the eccentric position of the headstock 31 with the workpiece W fixed can be calculated by subtracting the known second eccentric position from the third eccentric position. Then, to offset the rotational imbalance, a position 180 degrees inverted from this position is calculated and stored in the control unit 42 as the target correction position. (Step S9)

[0042] 7(e), the rotational phase of the tailstock 32 (second shaft member 321) in a state separated from the workpiece W is changed relative to the rotational phase of the headstock 31 to bring the second eccentric position closer to the target correction position (step S10). When the second eccentric position thus matches the target correction position (YES in step S11), the process returns to step S4.

[0043] That is, the headstock 31 and tailstock 32 are again brought close to each other, and while connected to the workpiece W, the acceleration within a predetermined time is measured (step S5). If the measured acceleration is equal to or greater than a predetermined value (NO in step S6), the above-mentioned rotation imbalance is corrected again (steps S7 to S11). On the other hand, if the measured acceleration is equal to or less than the predetermined value (YES in step S6), the process moves to machining of the workpiece W. That is, with the tool housing 22 rotated a predetermined angle around the Y axis (giving a cross angle), the support 21 is moved in the Y-axis direction, and the tool 236 is brought close to the workpiece W. Then, the workpiece W and the tool 236 are engaged, and machining of the workpiece W is performed (step S12).

[0044] In the above-described correction method, if the second eccentricity amount is significantly smaller than the eccentricity amounts of the headstock 31 and the workpiece W, a weight (not shown) may be intentionally attached to the second shaft member 321. Alternatively, the step of FIG. 7(a) can be omitted, and the workpiece W can be fixed to the headstock 31, rotated, and the acceleration and phase of the vibration generated in the first shaft member 311 measured immediately before connecting to the tailstock 32, and the eccentric position and eccentricity amount obtained based on this can be used as the first eccentric position. Thereafter, the headstock 31 and tailstock 32 can be connected, and the steps of FIGS. 7(c) to 7(e) can be performed.

[0045] <6. Features> According to this embodiment, the following effects can be obtained. (1) The eccentric positions of the first shaft member 311 and the second shaft member 321 can be measured. However, the eccentric position of the workpiece W has manufacturing variations for each workpiece W, and furthermore, since the fixing to the spindle head 31 is free, it is difficult to measure all of them. Therefore, in the present embodiment, the third eccentric position and the third eccentric amount when the first shaft member 311, the second shaft member 321, and the workpiece W are rotating integrally are calculated from the measured acceleration to identify the eccentric position on the spindle side including the workpiece W. Then, a correction target position is set from this eccentric position to cancel the rotational imbalance, and after moving the second eccentric position of the second shaft member 321 to the correction target position, the first shaft member 311, the second shaft member 321, and the workpiece W are rotated integrally, so that the correction of the rotational imbalance can be easily performed automatically. Therefore, the machining accuracy of the workpiece W can be improved.

[0046] (2) In the above gear machining apparatus, since the diameter of the workpiece W is smaller than the diameter of the tool 222, the rotational speed of the workpiece W is larger than that of the tool 222. Therefore, in the workpiece support unit 3, the influence of vibration due to rotational imbalance is greater than that in the tool support unit 2. Moreover, this is even more so when the rotational speed of the tool 222 is increased for mass production. Also, on the tool support unit 2 side, if the balance is corrected during manufacturing and maintenance, the imbalance amount can be kept low. However, on the workpiece support unit 3 side, since the workpiece W is randomly attached to the spindle head each time it is machined, there is a problem that the imbalance amount changes every time the workpiece is exchanged. Therefore, as in the present embodiment, if the rotational imbalance can be corrected in the workpiece support unit 3, the machining accuracy of the workpiece W can be further improved.

[0047] <B. Second Embodiment> Next, a second embodiment in which the machining apparatus according to the present invention is applied to a gear machining apparatus will be described while referring to the drawings. FIG. 8 is a front view of this gear machining apparatus.

[0048] As shown in FIG. 8, in this gear processing apparatus, a known automatic balancer 317 is provided on the second shaft member 321 of the centering base 32. The automatic balancer 317 can have various configurations. For example, it has a weight that is movable in the circumferential direction with respect to the rotating shaft inside it, and by measuring the acceleration during rotation, the eccentricity position and the amount of eccentricity are calculated. Then, the position of the weight that cancels out this amount of eccentricity is calculated, and the weight is moved. Thereby, the rotational imbalance is corrected. As shown in the first embodiment, a push-pull mechanism for clamping the workpiece is housed inside the first shaft member 311. However, since the second shaft member 321 side is simply a solid shaft, the automatic balancer 317 can be easily disposed.

[0049] Next, a gear processing method including a method for correcting rotational imbalance will be described with reference to FIG. 9. FIG. 9 is a flowchart showing a method for correcting rotational imbalance.

[0050] First, the workpiece W is attached to the first shaft member 311 of the spindle base 31. Subsequently, the spindle base 31 and the centering base 32 are brought close to each other to fix the workpiece W. In this state, the first shaft member 311, the second shaft member 321, and the workpiece W are integrally rotated for a predetermined time (step S21). Then, during this rotation, the rotational imbalance is corrected by the automatic balancer (step S22). After that, if the correction is completed (NO in step S23), the workpiece W is processed. That is, in order to impart a predetermined crossing angle, with the tool housing 22 rotated by a predetermined angle around the Y-axis, the support 21 is moved in the Y-axis direction, and the tool 236 is brought close to the workpiece W. Then, the workpiece W is processed by meshing and rotationally driving the workpiece W and the tool 236 (step S24).

[0051] In the gear processing apparatus according to the present embodiment, as in the first embodiment, the rotational imbalance is corrected in the workpiece support unit 3. Therefore, the machining accuracy of the workpiece W can be further improved.

[0052] <C. Modified Example> Although one embodiment of the present invention has been described above, the present invention is not limited to this, and various modifications are possible without departing from the spirit of the present invention. The following modifications can be combined as appropriate.

[0053] (1) In the second embodiment, the automatic balancer 317 is provided in the tailstock 32, but it may also be provided in the headstock 31. Alternatively, automatic balancers may be provided in both the headstock 31 and the tailstock 32.

[0054] As described above, since no push-pull mechanism is provided inside the tailstock 32, there is a certain amount of space inside the tailstock 32. From this perspective, it is therefore preferable to provide an automatic balancer in the tailstock 32. On the other hand, since the workpiece W is provided on the first shaft member 311 of the headstock 31, it is possible to calculate eccentricity, which has a greater effect on vibration. From this perspective, it is therefore preferable to provide an automatic balancer in the headstock 31.

[0055] (2) In the above embodiment, the support 324 of the tailstock 32 abuts against the workpiece W, thereby allowing the tailstock 32 to rotatably support the workpiece W together with the headstock 31. However, this is not limited to this. For example, as shown in FIG. 10 , an insertion portion 319 that is inserted into a through-hole in the workpiece W is provided at the tip of the headstock 31. This insertion portion 319 is provided with a movable locking portion (not shown, for example, a collet chuck) that is radially expandable and contractible, and the workpiece W is placed on it. Prior to machining, a pressing member 329 provided at the tip of the tailstock 32 abuts against and presses a recessed portion 319a of the insertion portion 319 located on the rotation center of the headstock 31 (see the dashed line in FIG. 10 ). As a result, the movable locking portion opens radially outward and presses the through-hole in the workpiece W from the inside, thereby fixing the workpiece W to the movable portion of the headstock 31 via the insertion shaft 319. During machining, the workpiece W is rotated by the headstock 31, but rotational runout of the workpiece W is suppressed by the pressing member 329 of the tailstock 32, which is positioned on the same axis as the recessed portion 319a of the insertion portion 319. In this way, the tailstock 32 does not necessarily have to have the function of directly supporting the workpiece W rotatably in cooperation with the headstock 31, but it only needs to be configured to at least stop rotational runout of the workpiece W rotated by the headstock 31, as shown in Figure 10.

[0056] In this case, an automatic balancer 317 can be built into the tailstock 31 as shown in FIG.

[0057] (3) In the above embodiments, the so-called honing process has been described. However, the present invention can be applied to general gear processing, such as shaving using an external gear-shaped tool.

[0058] (4) In the above embodiments, the present invention is applied to gear machining, but it can also be applied to other machining, for example, by a lathe. That is, the present invention can also be applied to machining the surface of a workpiece (for example, a rotationally symmetric body such as a cylinder) supported by a headstock and a tailstock using a tool such as a cutting tool. [Explanation of symbols]

[0059] 21 Spindle 22 Tailstock 4. Control section 5. Accelerometer double work

Claims

1. a preparation step of preparing a processing device including a headstock that is detachably fixed to a workpiece and that rotates about a first axis, a tailstock that is movable toward and away from the headstock in the first axis direction and that cooperates with the headstock to stop at least rotational runout of the workpiece when processing the workpiece, and a tool that processes the workpiece; a correcting step of correcting a rotational imbalance caused by at least one of the headstock, the tailstock, and the workpiece when the workpiece is rotationally driven in a state where the workpiece is supported by the headstock and the tailstock; a machining step of machining the workpiece with the tool after correcting the rotational imbalance; Equipped with The machining method, wherein the correction step is performed by adjusting the rotation phase of the headstock and the tailstock.

2. A preparation step of preparing a processing device having a headstock that can be detachably fixed to a workpiece and that rotates around a first axis, a tailstock that can be moved relatively close to and away from the headstock in the first axis direction and that is configured to cooperate with the headstock to stop at least rotational vibration of the workpiece when processing the workpiece, and a tool for processing the workpiece; a correcting step of correcting a rotational imbalance caused by at least one of the headstock, the tailstock, and the workpiece when the workpiece is rotationally driven in a state where the workpiece is supported by the headstock and the tailstock; a machining step of machining the workpiece with the tool after correcting the rotational imbalance; Equipped with The correction step a first step of acquiring a first eccentric position when the headstock rotates independently; a second step of obtaining a second eccentric position when the tailstock rotates independently; a third step of connecting the tailstock to the workpiece supported by the headstock; a fourth step of acquiring a third eccentric position when the headstock, the tailstock, and the workpiece rotate together; a fifth step of measuring vibrations caused by the unbalance of the rotation; a sixth step of temporarily separating the headstock and the tailstock when the vibration is equal to or greater than a predetermined value; a seventh step of calculating a correction position for correcting the rotational imbalance from the first to third eccentric positions; an eighth step of adjusting a rotational phase between the headstock and the tailstock in the separated state to move the second eccentric position to the correction position; The processing method includes:

3. A preparation step of preparing a processing device having a headstock that can be detachably fixed to a workpiece and that rotates around a first axis, a tailstock that can be moved relatively close to and away from the headstock in the first axis direction and that is configured to cooperate with the headstock to stop at least rotational vibration of the workpiece when processing the workpiece, and a tool for processing the workpiece; a correcting step of correcting a rotational imbalance caused by at least one of the headstock, the tailstock, and the workpiece when the workpiece is rotationally driven in a state where the workpiece is supported by the headstock and the tailstock; a machining step of machining the workpiece with the tool after correcting the rotational imbalance; Equipped with The correction step a first step of acquiring a first eccentric position of the headstock when the headstock rotates together with the workpiece fixed thereto; a second step of obtaining a second eccentric position when the tailstock rotates independently; a third step of connecting the tailstock to the workpiece supported by the headstock; a fourth step of acquiring a third eccentric position when the headstock, the tailstock, and the workpiece rotate together; a fifth step of measuring vibrations caused by the unbalance of the rotation; a sixth step of separating the headstock and the tailstock when the vibration is equal to or greater than a predetermined value; a seventh step of calculating a correction position for correcting the rotational imbalance from the first to third eccentric positions; an eighth step of adjusting a rotational phase between the headstock and the tailstock in the separated state to move the second eccentric position to the correction position; The processing method includes:

4. an acceleration sensor and an angle sensor are provided on each of the headstock and the tailstock; 4. The machining method according to claim 2, wherein the first to third eccentric positions are calculated based on the accelerations of the headstock and the tailstock measured by the acceleration sensor and the rotational phases of the headstock and the tailstock measured by the angle sensor.

5. 5. The processing method according to claim 2, wherein the third to eighth steps are repeated until the vibration measured in the fifth step becomes smaller than a predetermined value.

6. the workpiece is a gear to be machined, 6. The processing method according to claim 1, wherein the tool is a gear-shaped tool that processes the gear to be processed by meshing with the gear to be processed at a crossing angle and driving the gear to rotate.

7. a headstock that rotates the workpiece about a first axis; a tailstock that is movable relatively toward and away from the headstock in the first axial direction and is connected to the headstock to cooperate with the headstock to stop at least runout of the workpiece; a tool for processing the workpiece; a measuring device provided on the headstock or tailstock for measuring vibrations generated when the workpiece is rotated while supported by the headstock and tailstock; a control unit that corrects the rotational imbalance that causes the vibration by temporarily separating the headstock and the tailstock when the vibration is equal to or greater than a predetermined value, adjusting the rotational phase of the headstock and the tailstock, and then reconnecting them, and that starts machining of the workpiece by the tool when the vibration becomes smaller than the predetermined value; The processing device is provided with:

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