Processing method and processing device

Abstract

This invention provides a machining method and apparatus capable of suppressing rotational imbalance during machining. The machining method comprises: a preparation step, preparing a machining apparatus including: a spindle table that can be detachably fixed to a workpiece and driven to rotate about a first axis; a tailstock that can be relatively close to and detachable from the spindle table in the direction of the first axis, cooperating with the spindle table to rotatably support the workpiece during machining; a tool for machining the workpiece; a correction step, correcting rotational imbalance caused by at least one of the spindle table, the tailstock, and the workpiece while the workpiece is supported by the spindle table and the tailstock and driven to rotate; and a machining step, machining the workpiece using the tool after correcting the rotational imbalance.

Description

Technical Field

[0001] This invention relates to a processing method and a processing apparatus. Background Technology

[0002] Currently, honing is known as a finishing process for gears. In these processes, the workpiece and the grinding stone are rotated in a meshing state to achieve finishing.

[0003] For example, Patent Document 1 describes a gear machining apparatus for honing. In this apparatus, a workpiece is supported from both ends in the axial direction by a workpiece support unit consisting of a spindle table and a tailstock. A ring-shaped tool support unit with an internal gear-shaped tool, positioned between the two clamps, engages with the workpiece. Then, in this state, the tool of the tool support unit is rotated, thereby causing the workpiece and tool to rotate in tandem, and the workpiece is machined.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2003-25149 Summary of the Invention

[0007] The problem that the invention aims to solve

[0008] However, in the aforementioned machining process, due to the rotation of the tool and workpiece, an imbalance occurs because they are eccentric relative to the axis of rotation. As a result, vibrations that cannot be ignored during machining occur, potentially reducing machining accuracy. Various proposals have been made to address this rotational imbalance, but there is still room for improvement. Furthermore, this problem is prevalent not only in gear machining but also in machining methods that involve rotating rotationally symmetric bodies such as cylindrical objects while machining.

[0009] The present invention was developed to solve the above-mentioned problems, and its purpose is to provide a processing method and processing apparatus that can suppress rotational imbalance during processing.

[0010] Technical solutions for solving the problem

[0011] The processing method of the present invention comprises: a preparation step, wherein a processing apparatus is prepared, the processing apparatus having: a spindle table, which can be detachably fixed to a workpiece and driven to rotate about a first axis; a tailstock (tail support), configured to be relatively close to and detachable relative to the spindle table in the direction of the first axis, and cooperating with the spindle table to at least prevent rotational vibration of the workpiece when processing the workpiece; a tool for processing the workpiece; a correction step, wherein, while the workpiece is supported by the spindle table and the tailstock, a rotational imbalance caused by at least one of the spindle table, the tailstock, and the workpiece is corrected when the workpiece is driven to rotate; and a processing step, wherein, after the rotational imbalance is corrected, the workpiece is processed by the tool.

[0012] In the above processing method, the correction step may include: a first step, obtaining a first eccentric position when the spindle table rotates alone; a second step, obtaining a second eccentric position when the tailstock rotates alone; a third step, connecting the tailstock relative to the workpiece supported by the spindle table; a fourth step, obtaining a third eccentric position when the spindle table, the tailstock, and the workpiece rotate as a whole; a fifth step, measuring the vibration caused by the rotational imbalance; a sixth step, temporarily separating the spindle table and the tailstock if the vibration exceeds a predetermined value; a seventh step, calculating a correction position for correcting the rotational imbalance based on the first to third eccentric positions; and an eighth step, adjusting the rotational phase of the spindle table and tailstock in the separated state, so that the second eccentric position moves towards the correction position.

[0013] In the above processing method, the correction step may include: a first step, obtaining a first eccentric position when the spindle table fixes the workpiece and rotates together; a second step, obtaining a second eccentric position when the tailstock rotates alone; a third step, connecting the tailstock relative to the workpiece supported by the spindle table; a fourth step, obtaining a third eccentric position when the spindle table, the tailstock, and the workpiece rotate as a whole; a fifth step, measuring the vibration caused by the rotational imbalance; a sixth step, separating the spindle table and the tailstock if the vibration exceeds a predetermined value; a seventh step, calculating a correction position for correcting the rotational imbalance based on the first to third eccentric positions; and an eighth step, adjusting the rotational phase of the spindle table and tailstock in the separated state, so that the second eccentric position moves towards the correction position.

[0014] In the above processing method, the following configuration can be made: an acceleration sensor and an angle sensor are respectively provided on the spindle table and the tailstock; the first to third eccentric positions are calculated based on the acceleration of the spindle table and the tailstock measured by the acceleration sensor and the rotational phase of the spindle table and the tailstock measured by the angle sensor.

[0015] In the above processing method, steps three through eight can be repeated until the vibration measured in step five is smaller than the specified value.

[0016] In the above processing method, it can be configured such that at least one of the spindle table and the tailstock is provided with an automatic balancer to correct rotational imbalance. In the correction step, the automatic balancer corrects the rotational imbalance when the spindle table, the tailstock and the workpiece rotate together.

[0017] In the above processing method, the automatic balancer can be installed on the spindle table.

[0018] In the above processing method, the automatic balancer can be provided on the tailstock.

[0019] In the above processing method, the workpiece can be a gear, and the tool can be a gear-shaped tool that meshes with the gear by giving a cross angle and rotates to process the gear.

[0020] The first processing apparatus of the present invention comprises: a spindle table for driving the workpiece to rotate about a first axis; a tailstock configured to be relatively close to and freely separate relative to the spindle table in the direction of the first axis, connected to and cooperating with the spindle table to at least prevent rotational vibration of the workpiece; a tool for processing the workpiece; a measuring device disposed on the spindle table or the tailstock for measuring vibration generated when the workpiece is rotated while supported by the spindle table and the tailstock; and a control unit that, when the vibration is above a predetermined value, corrects the rotational imbalance caused by repeated actions of temporarily separating the spindle table and the tailstock and then reconnecting them after adjusting the rotational phase of the spindle table and the tailstock, and starts processing of the workpiece by the tool when the vibration is below the predetermined value.

[0021] The second processing apparatus of the present invention comprises: a spindle table for driving the workpiece to rotate about a first axis; a tailstock configured to be relatively close to and separated from the spindle table in the direction of the first axis, thereby preventing rotational vibration of the workpiece from being prevented between the tailstock and the spindle table; a tool for processing the workpiece; and an automatic balancer disposed on at least one of the spindle table and the tailstock for correcting rotational imbalance, wherein the automatic balancer corrects the rotational imbalance when the spindle table, the tailstock, and the workpiece rotate together.

[0022] Invention Effects

[0023] According to the present invention, rotational imbalance during processing can be suppressed. Attached Figure Description

[0024] Figure 1 This is a front view showing the application of the processing apparatus of the present invention to a gear processing apparatus in a first embodiment.

[0025] Figure 2 yes Figure 1 A-A sectional view.

[0026] Figure 3 yes Figure 2 Sectional view along line B-B.

[0027] Figure 4 This is an enlarged sectional view of a portion of the workpiece support unit.

[0028] Figure 5 This is a block diagram of the control unit.

[0029] Figure 6 This is a flowchart illustrating the gear machining method of the first embodiment.

[0030] Figure 7 This is a diagram illustrating the correction of rotational imbalance.

[0031] Figure 8 This is a partial cross-sectional view of the workpiece support unit in a second embodiment of applying the processing apparatus of the present invention to a gear processing apparatus.

[0032] Figure 9 This is a flowchart illustrating the gear machining method of the second embodiment.

[0033] Figure 10 This is a side view showing other examples of the spindle table and tailstock. Detailed Implementation

[0034] <A. First Implementation>

[0035] Hereinafter, a first embodiment of applying the processing apparatus of the present invention to a gear processing apparatus will be described with reference to the accompanying drawings. Figure 1 This is the front view of the gear machining device. Figure 2 yes Figure 1 A-A line sectional view, Figure 3 yes Figure 1 The B-B line view. Furthermore, in the following description, Figure 1 The left and right directions are called the X-axis (the direction of the first axis). Figure 1 The vertical direction is called the Z-axis. Figure 2 The left-right direction is referred to as the Y-axis. Then, the description will be based on the display of directions (up, down, front, back, left, right) indicated along with the markings of the X, Y, and Z axes. However, these directions are only one aspect of the invention and may be other configurations; therefore, the invention is not limited to these directions.

[0036] <1. Overview of Gear Machining Equipment>

[0037] like Figures 1-3 As shown, the gear machining apparatus of this embodiment includes: a base 1, a tool support unit 2 and a workpiece support unit 3 disposed thereon, and a control unit 4 for driving control devices, etc. The tool support unit 2 has a support body 21 and a tool housing 22 connected to the front of the support body 21 and on which an internal gear-shaped tool (grinding stone) 222 is mounted. The axial direction of the tool 222 is arranged approximately toward the X-axis. Thus, the tool 222 meshes with the gear being machined, which is the workpiece W.

[0038] On the other hand, the workpiece support unit 3 is composed of a spindle stage 31 and a tailstock 32 that support the workpiece W, which are arranged on both sides of the base 1, sandwiching the tool support unit 2. The following is a detailed description of each unit 2, 3, and the control unit 4.

[0039] <2. Tool Support Unit>

[0040] First, the tool support unit 2 will be described in detail. For example... Figure 2 As shown, a shaft member 211 extending along the Y-axis is provided on the aforementioned support body 21, and a tool housing 22 is mounted on the front side of the shaft member 211. The shaft member 211 is rotatably supported about the Y-axis, so when the shaft member 211 rotates, the tool housing 22 rotates about the Y-axis. As a result, a cross angle can be applied to the workpiece W.

[0041] Additionally, though the diagram is omitted, the support 21 can reciprocate along the Y-axis on the base 1, thereby enabling the tool 222 to cut the workpiece W. The unit that moves the support 21 is not particularly limited, but for example, the support 21 can be movably supported on a track extending along the Y-axis on the base 1, and moved along the track by known devices such as ball screws, nuts, and motors.

[0042] Next, the tool housing 22 will be described. For example... Figure 2 and Figure 3 As shown, the tool housing 22 has an annular support portion 221 connected to the aforementioned shaft component 211, and this support portion 221 is configured such that its axial direction is approximately oriented towards the X-axis. Furthermore, an annular internal gear-shaped tool 222 is rotatably mounted on the inner circumferential surface of the support portion 221 via a bearing 23. The workpiece W is machined while engaging with the tool 222 from the inside. A drive gear 223 is mounted on the outer circumferential surface of the tool 222, and this drive gear 223 is rotated by a motor 224 fixed to the upper part of the support portion 235. That is, a speed reducer (not shown) is provided between the motor 224 and the drive gear 223, so that when the motor 224 is driven, the drive gear 223 rotates together with the tool 222 according to a predetermined reduction ratio. Furthermore, the motor 224 is electrically connected to the control unit 4 for driving the motor 224.

[0043] <3. Workpiece Support Unit>

[0044] Next, also refer to Figure 4 The workpiece support unit 3 will be described. Figure 4 This is an enlarged sectional view of the workpiece support unit. For example... Figure 1 and Figure 3 As shown, the workpiece support unit 3 is composed of the aforementioned spindle head 31 and tailstock 32, clamping the tool housing 22. The spindle head 31 is positioned on the left side along the X-axis, and the tailstock 32 is positioned on the right side. Furthermore, these spindle heads 31 and tailstocks 32 are close to and separate from each other along the X-axis, and rotatably support the workpiece W. The spindle head 31 is provided with a first shaft component 311 that engages with the workpiece W and extends along the X-axis. This first shaft component 311 is rotated about the X-axis by a motor 312 built into the spindle head 31.

[0045] like Figure 4As shown, a passage 313 extending along the X-axis is formed on the first shaft member 311. A spring collet 314, movable along the X-axis and expanding and contracting radially with movement along the X-axis, is mounted on the outer peripheral surface of the opening at the front end of the passage 313. Furthermore, a movable part 315 of a push-pull mechanism for expanding and contracting the spring collet 314 is inserted into the passage 311. Thus, when a workpiece W is mounted on the spring collet 314, i.e., when the spring collet 314 is inserted into the through hole of the workpiece W, if the movable part 315 is pulled to the left, the spring collet 314 expands in diameter, and the workpiece W is clamped by the first shaft member 311 via the spring collet 314. Additionally, a cylindrical support 316 is fixed at the front end of the first shaft member 311 to surround the spring collet 314. This support 316 contacts the left side of the workpiece W and supports the workpiece W.

[0046] Furthermore, the spindle stage 31 is mounted on a first guide rail 15 that extends along the X-axis and is positioned on the base 1, and moves along the first guide rail 15. A nut (not shown) is fixed to the lower part of the spindle stage 31, and a ball screw (not shown) is screwed into the nut. The ball screw extends along the X-axis and is connected to a motor (not shown) fixed to the base 1. Therefore, driven by the motor, the ball screw rotates, and consequently, the spindle stage 31 moves along the X-axis.

[0047] The tailstock 32 is configured identically to the main spindle stage 31. Specifically, the tailstock 32 and the first shaft member 311 of the main spindle stage 31 are engaged on the same axis, and a second shaft member 321 extending in the X direction is provided. This second shaft member 321 is rotatably supported about the X-axis and rotates about the X-axis via a motor 322 built into the tailstock 32. A recess 323 is formed at the front end of the second shaft member 321 for inserting the front end of a movable portion 315 protruding from the first shaft member 311. Furthermore, a support 324, which abuts against the right side surface of the workpiece W, is mounted at the front end of the second shaft member 321 to surround the recess 323.

[0048] The tailstock 32 is mounted on a second guide rail 16 that is mounted on the base 1 and extends along the X-axis, and moves along the second guide rail 16. The tailstock 32 is also the same as the main spindle 31, and is driven by a nut, ball screw and motor (not shown) to move along the X-axis.

[0049] Furthermore, after the workpiece W is clamped by the first axis component 311, it moves to the right of the paper while rotating at the machining speed via the motor 312 during machining. Simultaneously, the second axis component 321 also moves to the left of the paper while rotating synchronously via the motor 322. The two supports 316 and 324 are connected at a predetermined position to clamp the workpiece W. Thus, workpiece support is completed. Furthermore, before the workpiece W is supported by the spindle table 31 and tailstock 32, if both the spindle table 31 and tailstock 32 are rotated first (if the spindle table 31 and tailstock 32 are brought close together while rotating), pre-machining preparation can be completed earlier. Figure 3 As shown, with the workpiece W supported by the spindle table 31 and the tailstock 32, the spindle table 31 and the tailstock 32 move synchronously along the X-axis, thereby causing the workpiece W to also move along the X-axis.

[0050] Furthermore, such as Figure 1 As shown, accelerometers 5a and 5b and angle sensors 8a and 8b (not shown) are installed on the spindle table 31 and tailstock 32 to pre-measure the inherent vibration acceleration generated when the spindle table 31 and tailstock 32 rotate individually, as well as the phase of the first shaft component 311 and the second shaft component 321. Furthermore, during machining, as described above, the acceleration and phase of the vibration generated when the workpiece W is rotated and supported by the spindle table 31 and tailstock 32 are also measured using one of the accelerometers 5a and 5b and the angle sensor. That is, the acceleration and phase generated when the first shaft component 311, the second shaft component 322, and the workpiece W are rotated as a single unit are also measured. As described later, the measured acceleration and phase are stored in the storage unit 42 provided in the control unit 4.

[0051] <4. Control Unit>

[0052] Next, refer to Figure 5 The control unit 4 will be explained. For example... Figure 5 As shown, the control unit 4 can be composed of a PLC with a CPU 41, RAM (not shown), and a storage unit 42, and a general-purpose computer, and can control various drives of the gear processing device. Furthermore, by separating this control unit 4 from the control unit that drives the gear processing device, it is also possible to primarily perform only the correction of rotational imbalances, as described later.

[0053] In particular, in the control unit 4, the acceleration and phase measured by the spindle stage 31 and the tailstock 32 are received by the acceleration sensors 5a and 5b and the angle sensors 8a and 8b, respectively, thereby correcting the imbalance of the workpiece W during rotation.

[0054] like Figure 5As shown, the storage unit 42 of the control unit 4 stores a correction program 421 for correcting the rotational imbalance of the workpiece W, and the CPU 41 executes the program 421. Details of the correction method will be described later. In addition, the storage unit 42 stores data on the eccentric position and eccentricity of the first axis component 311 of the spindle table 31 (spindle table eccentricity data) 422, data on the eccentric position and eccentricity of the second axis component 321 of the tailstock 32 (tailstock eccentricity data) 423, data on the eccentric position and eccentricity of the spindle table 31, tailstock 32, and workpiece W when connected (connection eccentricity data) 424, acceleration data measured by the accelerometer 5 425, and correction target data 426 on the eccentric position and eccentricity corrected by correction.

[0055] <5. Methods for correcting rotational imbalance>

[0056] Next, refer to Figure 6 A gear machining method incorporating a method for correcting rotational imbalances is described. Figure 6 This is a flowchart illustrating a method for correcting rotational imbalances.

[0057] First, as information inherent to the machine due to tolerances and assembly errors of each component, a first eccentricity position (spindle eccentricity data) indicating the eccentricity position of the first shaft member 311 of the spindle stage 31 and a second eccentricity position (tailstock eccentricity data) indicating the eccentricity position of the second shaft member 321 of the tailstock 32 are pre-acquired and stored in the storage unit 42. This eccentricity position can be obtained, for example, using a known one-sided correction method. For instance, when obtaining the eccentricity position of the first shaft member 311, the first shaft member 311 is rotated independently, and the eccentricity position is obtained using a one-sided correction method based on the vibration of the first shaft member 311 obtained by the accelerometer 5 and the phase obtained by the angle sensor 8. The second eccentricity position and the third eccentricity position, described later, can also be obtained in the same way.

[0058] In addition, in this embodiment, besides the eccentric position, the eccentricity amount is also obtained, but for ease of explanation, it is sometimes simply referred to as the eccentric position.

[0059] Next, according to Figure 6The imbalance correction of workpiece W performed before processing is explained. First, the first and second eccentric positions stored in the storage unit 42 are read (step S1). Next, workpiece W is fixed to the spindle table 31, and workpiece W is rotated together with the first shaft member 311 (step S2). Next, after rotating the second shaft member 321 of the tailstock 32 (step S3), the spindle table 31 and tailstock 32 are brought close together, and workpiece W is supported by both (step S4). Then, the acceleration is measured for a specified time by the acceleration sensor of the first shaft member 311 or the second shaft member 321 (step S5). If the measured acceleration is above a specified value (NO in step S6), the rotational imbalance is corrected. In addition, at this time, the phase is also measured by the angle sensor of the first shaft member 311 or the second shaft member 321, and the third eccentric position obtained based on the phase data and the aforementioned acceleration data is stored in the storage unit 42 (step S7).

[0060] That is, if the acceleration is above a specified value, a non-negligible rotational imbalance may occur due to the combined eccentricity of the first shaft component 311, the second shaft component 321, and the workpiece W, thus causing vibration. Therefore, firstly, the spindle table 31 and the tailstock 32 are separated (step S8).

[0061] Next, the control unit 4 calculates the target position for imbalance correction (step S9). This will be explained in detail. Based on the measured acceleration, the peak value of the acceleration, the rotational position where the peak value is generated, etc., can be calculated, thereby obtaining the first to third eccentric positions as described above.

[0062] Therefore, the control unit 4 calculates the corrected target position for correcting the imbalance of rotation caused by the third eccentric position and the third eccentricity. Figure 7 (a)~ Figure 7 (e) Briefly describe its calculation method. Figure 7 (a) indicates the first eccentric position calculated from the main spindle stage 31 (first shaft component 311) alone. Figure 7 (b) indicates the second eccentric position calculated from the tailstock 32 (second shaft component 321) unit. Figure 7 (c) indicates the third eccentric position, but this is a position where the eccentricity of workpiece W is combined with the first and second eccentric positions mentioned above. Therefore, as Figure 7 As shown in (d), by subtracting the known second eccentric position from the third eccentric position, the eccentric position of the spindle stage 31 with the workpiece W fixed can be calculated. Furthermore, in order to counteract the rotational imbalance, a position reversed by 180 degrees from this position is calculated as the target correction position and stored in the control unit 42. (Step S9)

[0063] Next, as Figure 7As shown in (e), the rotational phase of the tailstock 32 (second shaft component 321) is changed relative to the rotational phase of the spindle stage 31 from the state separated from the workpiece W, so that the second eccentric position is close to the target correction position (step S10). Thus, when the second eccentric position is consistent with the target correction position (YES in step S11), the process returns to the aforementioned step S4.

[0064] That is, the spindle head 31 and tailstock 32 are brought closer together again, and the acceleration is measured within a specified time while connected to the workpiece W (step S5). Furthermore, if the measured acceleration is above a specified value (NO in step S6), the aforementioned rotational imbalance correction is performed again (steps S7 to S11). On the other hand, if the measured acceleration is below a specified value (YES in step S6), the machining of the workpiece W is initiated. That is, while the tool housing 22 is rotated around the Y-axis by a specified angle (giving an intersecting angle), the support 21 is moved along the Y-axis, bringing the tool 236 closer to the workpiece W. Then, the workpiece W and tool 236 are engaged, and the workpiece W is machined.

[0065] (Step S12)

[0066] Furthermore, in the above-described correction method, when the second eccentricity is significantly smaller than the eccentricity of the spindle table 31 and the workpiece W, a counterweight (not shown) may be intentionally mounted on the second shaft component 321. Additionally, [details omitted]. Figure 7 In step (a), after fixing the workpiece W on the spindle table 31 and rotating it, before connecting it to the tailstock 32, the acceleration and phase of the vibration generated on the first shaft component 311 are measured. The eccentric position and eccentricity obtained based on these parameters can be set as the first eccentric position. Then, the spindle table 31 and the tailstock 32 can be connected to perform... Figure 7 (c)~ Figure 7 (e) process.

[0067] <6. Characteristics>

[0068] According to this embodiment, the following effects can be obtained.

[0069] (1) While the eccentric positions of the first shaft component 311 and the second shaft component 321 can be measured, the eccentric position of the workpiece W varies due to manufacturing differences in each workpiece W. Furthermore, since the spindle table 31 is freely fixed, it is difficult to measure all of them. Therefore, in this embodiment, the third eccentric position and the third eccentric amount when the first shaft component 311, the second shaft component 321, and the workpiece W rotate as a whole are calculated based on the measured acceleration, and the eccentric position on the spindle side of the workpiece W is specifically included. Moreover, by setting a correction target position based on this eccentric position and offsetting the rotational imbalance, the second eccentric position of the second shaft component 321 is moved to the aforementioned correction target position, and the first shaft component 311, the second shaft component 321, and the workpiece W rotate as a whole. Therefore, the rotational imbalance can be corrected automatically and easily. Thus, the machining accuracy of the workpiece W can be improved.

[0070] (2) In the gear machining apparatus described above, the diameter of the workpiece W is smaller than the diameter of the tool 222, therefore, the rotational speed of the workpiece W is greater than that of the tool 222. Consequently, in the workpiece support unit 3, the vibration caused by rotational imbalance is greater compared to the tool support unit 2. This is especially true when the tool 222 is rotated at a high speed for mass production. Furthermore, while in the tool support unit 2, balancing correction during manufacturing and maintenance can maintain a low level of imbalance, in the workpiece support unit 3, the workpiece W is randomly mounted on the spindle table during each machining operation, resulting in a change in imbalance each time the workpiece is changed. Therefore, as in this embodiment, when rotational imbalance can be corrected in the workpiece support unit 3, the machining accuracy of the workpiece W can be further improved.

[0071] <B. Second Implementation>

[0072] Next, a second embodiment of applying the processing apparatus of the present invention to a gear processing apparatus will be described with reference to the accompanying drawings. Figure 8 This is the front view of the gear processing device.

[0073] like Figure 8 As shown, in this gear machining apparatus, a known automatic balancer 317 is provided on the second shaft member 321 of the tailstock 32. The automatic balancer 317 can have various structures, but for example, it has a weight movable circumferentially relative to the rotation axis inside it. By measuring the acceleration during rotation, the eccentric position and eccentricity are calculated. Then, the position of the weight that offsets the eccentricity is calculated, and the weight is moved. Thus, 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, but the second shaft member 321 side is only a solid shaft, therefore, the automatic balancer 317 can be easily installed.

[0074] Next, refer to Figure 9 A gear machining method incorporating a method for correcting rotational imbalances is described. Figure 9 This is a flowchart illustrating a method for correcting rotational imbalances.

[0075] First, the workpiece W is mounted on the first axis component 311 of the spindle table 31. Next, the spindle table 31 and tailstock 32 are brought close together to fix the workpiece W. In this state, the first axis component 311, the second axis component 321, and the workpiece W are rotated together for a predetermined time (step S21). During this rotation, any imbalance is corrected by an automatic balancer (step S22). Then, if the correction is complete (step S23 NO), the workpiece W is machined. That is, to achieve a predetermined cross angle, while the tool housing 22 is rotated about the Y-axis by a predetermined angle, the support 21 is moved along the Y-axis, bringing the tool 236 close to the workpiece W. Furthermore, the workpiece W is machined by engaging and rotating the workpiece W and tool 236 (step S24).

[0076] In the gear machining apparatus of this embodiment, similar to 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.

[0077] <C. Variation>

[0078] The present invention has been described above as one embodiment, but the invention is not limited thereto, and various modifications can be made without departing from its spirit. Furthermore, the following variations can be appropriately combined.

[0079] (1) In the second embodiment, an automatic balancer 317 is provided on the tailstock 32, but it can also be provided on the spindle table 31. Alternatively, an automatic balancer can be provided on both the spindle table 31 and the tailstock 32.

[0080] As mentioned above, no push-pull mechanism is provided inside the tailstock 32, therefore, there is some space inside the tailstock 32. Therefore, from this viewpoint, it is preferable to provide an automatic balancer on the tailstock 32. On the other hand, the workpiece W is provided on the first shaft member 311 of the spindle table 31, therefore, it is possible to calculate the eccentricity that further affects vibration. Therefore, from this viewpoint, it is preferable to provide an automatic balancer on the spindle table 31.

[0081] (2) In the above embodiment, the tailstock 32 abuts against the workpiece W via its support body 324, and the tailstock 32 and the main spindle 31 rotatably support the workpiece W, but this is not limited to this. For example, such as Figure 10As shown, a through-hole 319 is provided at the front end of the spindle table 31, through which the workpiece W is inserted. This through-hole 319 has a movable locking part (not shown, but could be a spring collet, for example) that expands and contracts radially, and holds the workpiece W. Before machining, a pressing member 329 located at the front end of the tailstock 32 abuts against and presses against the recess 319a of the through-hole 319 located at the rotation center of the spindle table 31 (see reference). Figure 10 (A single-dot dashed line). Thus, a through hole is configured to open radially outward through a movable locking portion and press the workpiece W inward. The workpiece W is fixed to the movable portion of the spindle table 31 via the insertion shaft portion 319. During machining, the workpiece W rotates via the spindle table 31, but the rotational vibration of the workpiece W is suppressed by the pressing member 329 of the tailstock 32, which is located on the same axis via the recess 319a of the insertion portion 319. Therefore, the tailstock 32 does not necessarily need to have the function of directly rotatably supporting the workpiece W in cooperation with the spindle table 31, such as... Figure 10 It is sufficient that the workpiece W is configured to at least prevent rotational vibration of the workpiece W rotating through the spindle table 31.

[0082] In this case, such as Figure 10 As shown, an automatic balancer 317 can be built into the tailstock 31.

[0083] (3) In the above embodiments, the so-called honing process has been described, but the present invention can be applied to all gear processing such as shaving of tools using external gears.

[0084] (4) In the above embodiments, examples of applying the present invention to gear machining have been shown, but it can also be applied to lathe machining, for example. That is, the present invention can also be applied when the workpiece (e.g., a rotationally symmetric body such as a cylinder) is supported by a spindle table and a tailstock, and the surface of the workpiece is machined by a cutting tool or the like.

[0085] Symbol Explanation

[0086] 21 spindles

[0087] 22 tails

[0088] 4 Control Department

[0089] 5 Accelerometers

[0090] W workpiece.

Claims

1. A processing method comprising: a preparation step of preparing a processing device having: a spindle head that can freely fix and rotationally drive a workpiece around a first axis; a tailstock configured to be relatively approachable and separable from the spindle head in the direction of the first axis, and to at least stop rotational vibration of the workpiece in cooperation with the spindle head when processing the workpiece; and a tool that processes the workpiece; a correction step of correcting rotational imbalance caused by at least one of the spindle head, the tailstock, and the workpiece when the workpiece is rotationally driven in a state of being supported by the spindle head and the tailstock; and a processing step of processing the workpiece by the tool after the correction of the rotational imbalance.

2. The processing method according to claim 1, wherein the correction step comprises: a first step of acquiring a first eccentric position when the spindle head is rotated alone; a second step of acquiring a second eccentric position when the tailstock is rotated alone; a third step of connecting the tailstock with respect to the workpiece supported by the spindle head; a fourth step of acquiring a third eccentric position when the spindle head, the tailstock, and the workpiece are rotationally integrated; a fifth step of measuring vibration generated due to the rotational imbalance; a sixth step of temporarily separating the spindle head 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 based on the first to third eccentric positions; and an eighth step of adjusting the rotational phase of the spindle head and the tailstock in the separated state so that the second eccentric position moves to the correction position.

3. The processing method according to claim 1, wherein the correction step comprises: a first step of acquiring a first eccentric position when the spindle head fixes and rotates the workpiece together; a second step of acquiring a second eccentric position when the tailstock is rotated alone; a third step of connecting the tailstock with respect to the workpiece in a state of being supported by the spindle head; a fourth step of acquiring a third eccentric position when the spindle head, the tailstock, and the workpiece are rotationally integrated; a fifth step of measuring vibration generated due to the rotational imbalance; a sixth step of separating the spindle head 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 based on the first to third eccentric positions; and an eighth step of adjusting the rotational phase of the spindle head and the tailstock in the separated state so that the second eccentric position moves to the correction position.

4. The processing method according to claim 2 or 3, wherein an acceleration sensor and an angle sensor are respectively provided on the spindle head and the tailstock. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ The first to third eccentric positions are calculated based on the accelerations of the spindle head and the tailstock measured by the acceleration sensor and the rotational phases of the spindle head and the tailstock measured by the angle sensor.

5. The processing method according to claim 2 or 3, wherein The third to eighth steps are repeated until the vibration measured in the fifth step is smaller than a predetermined value.

6. The processing method according to any one of claims 1 to 3, wherein The workpiece is a workpiece gear, The tool is a gear-shaped tool that meshes with the workpiece gear by being given a cross angle and rotates the workpiece gear.

7. A processing apparatus comprising: a spindle head that rotates and drives a workpiece around a first axis; a tailstock configured to relatively approach and separate from the spindle head in the direction of the first axis, and coupled to and cooperates with the spindle head to at least stop rotational vibration of the workpiece; a tool that processes the workpiece; a measurement device provided to the spindle head or the tailstock, and measures vibration generated when the workpiece is rotated while being supported by the spindle head and the tailstock; a control unit that, when the vibration is equal to or greater than a predetermined value, corrects rotational imbalance that causes the vibration due to repeated operations of temporarily separating the spindle head and the tailstock and re-coupling after adjusting rotational phases of the spindle head and the tailstock, and when the vibration is smaller than the predetermined value, starts processing of the workpiece by the tool.

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