JP2015186831A - Helical gear machining method, and machining device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and a device capable of machining a helical gear with high accuracy from the beginning.SOLUTION: A machining method includes: a primary machining step S3 for rotating work W fixed on a work table 7 around a Y-axis at predetermined rotation speed, and forming a tooth trace on an outer periphery of the work at a cut-in position shallower than tooth depth to be finally formed, while reciprocating a cutter 11 along the Y-axis at predetermined propulsion speed; a measuring step S4 for measuring the shape of the tooth trace formed in the primary machining step while fixing the work W on the work table 7; a calculating step S5 for calculating a cutting error of the tooth trace on the basis of a measurement result obtained by the measuring step and a set value of the tooth trace to be formed in the primary machining; a correcting step S6 for correcting the set value of the tooth trace on the basis of the calculated error; and a secondary machining step S8 for carrying out secondary machining on the basis of the set value of the tooth trace which is corrected in the correcting step.

Description

  The present invention relates to a helical gear machining method and machining apparatus, and more particularly to a helical gear machining method using a gear shaper and such a machining apparatus.

  Conventionally, a work table to which the workpiece that is the base of the gear is fixed is rotated around the axis, and the pinion cutter is reciprocated in the axial direction according to the helical angle of the tooth line to be formed, and combined rotation around the axis There is known a method of processing a helical gear by forming tooth lines on the outer periphery of a workpiece (for example, Patent Document 1).

JP-A-10-109223

  In the technique described in Patent Document 1, a motor for rotating the pinion cutter is provided separately from a motor for propelling the pinion cutter in the vertical direction along the axis, and various control is performed by combining the two motors. It is possible to easily form a helical line having a helical angle.

  However, when processing helical gears with various helical angles, it is difficult to process the first workpiece immediately after changing the gear shaper control value, and it must be discarded. There were many. Specifically, the control value of the gear shaper does not take into consideration the resistance value of the workpiece with respect to the cutter during processing. Therefore, immediately after changing the control value of the gear shaper, it has been necessary to perform a test once, measure the shape of the tooth trace of the processed workpiece, and feed back the measurement result. In this case, the processing accuracy of the tooth trace of the first workpiece often cannot satisfy the target accuracy, and often has to be discarded. In particular, when machining a large gear, the economic loss due to discarding a single workpiece is particularly undesirable.

  Accordingly, the present invention has been made to solve the above-described problems, and an object thereof is to provide a machining method and a machining apparatus capable of machining a highly accurate helical gear from the beginning.

  In order to solve the above-described problem, the present invention provides a cutter on the outer peripheral surface of a workpiece while rotating the workpiece around a first axis and moving the cutter along a second axis parallel to the first axis. A helical gear machining method that cuts the tooth traces on the outer periphery of the workpiece by contacting the workpiece, wherein the workpiece fixed on the workpiece table is rotated at a predetermined rotational speed around the first axis, and the cutter is A primary processing step of forming a streak on the outer periphery of the workpiece at a cutting position shallower than a tooth to be finally formed while reciprocating along the second axis at a predetermined propulsion speed, and the workpiece on the work table The measurement of the tooth streak formed in the primary machining process while being fixed, the measurement result obtained in the measurement process, and the set value of the tooth streak to be formed in the primary machining Calculate the cutting error A correction process for correcting the setting value of the tooth trace based on the calculated error, and a work fixed to the work table based on the set value of the tooth trace corrected in the correction process are rotated around the first axis, And a secondary processing step of cutting the tooth streak to the depth of the tooth to be finally formed on the work fixed to the work table while reciprocating the cutter along the second axis.

  According to the present invention configured as described above, in the primary processing step, a tooth streak is formed at a cutting depth shallower than a tooth to be finally formed, and the shape of the tooth streak is measured while the workpiece is fixed. be able to. Therefore, it is not necessary to remove the workpiece from the work table when performing measurement for calculating the cutting error. Then, the cutting error is calculated from the measurement result in the measuring process, the set value of the tooth streak is corrected based on the cutting error, and then the primary machining process is performed and the workpiece that is fixed to the work table is corrected. A secondary processing step is performed based on the set value of the tooth trace, and a helical gear having a tooth trace to be finally formed can be obtained. In this way, the work used to calculate the cutting error by temporarily stopping the machining operation during the helical gear machining, correcting the cutting error while fixing the workpiece to the work table, and then restarting the machining operation. Can be cut with high accuracy.

  Preferably, in the present invention, in the measurement process, a contact-type measuring instrument fixed to the saddle, which is movable along a third axis parallel to the second axis and does not contribute to the primary machining process, is provided. Prepare and measure the tooth trace by bringing the contact point of the contact type measuring instrument into contact with the tooth trace cut in the primary machining process, and drive the saddle and the work table synchronously based on the target value of the tooth trace, In the correction step, the cutting error is calculated based on the difference between the set value of the tooth line to be formed in the primary processing and the measurement result obtained in the measurement step.

  According to the present invention configured as described above, the tooth trace actually processed by the primary processing is measured using the saddle which does not contribute to the primary processing, and the actually formed tooth streak and the primary processing are formed. It is possible to calculate a cutting error between the set value of the tooth trace to be performed. In this way, the saddle that does not contribute to the primary machining is synchronized with the work table and is actually machined while reproducing the movement in the second axis direction and the rotation around the first axis based on the set value of the tooth trace in the primary machining. By measuring the tooth trace, the cutting error can be accurately calculated.

  Preferably, in the present invention, in the measuring step, the shape of the tooth trace formed in the primary machining process is automatically measured by scanning the workpiece, in which the tooth trace is cut in the primary machining process, with a laser.

  According to the present invention configured as described above, the shape of the tooth streak formed in the primary processing step can be measured by laser scanning, and therefore the shape of the tooth streak can be measured with high accuracy.

  In this case, it is preferable to perform the secondary processing step after repeating the primary processing step, the measurement step, and the correction step a plurality of times. Thereby, cutting errors can be reduced as much as possible, and a helical gear with higher accuracy can be machined.

  Further, in order to solve the above-described problems, the present invention is configured to rotate the workpiece around the first axis and move the cutter along the second axis parallel to the first axis to the outer peripheral surface of the workpiece. A helical gear machining device that cuts teeth on the outer periphery of a workpiece by bringing the cutter into contact with the workpiece. The workpiece is fixed, and the fixed workpiece is rotated about a first axis at a predetermined rotation speed. A work table, a cutter head that reciprocates the cutter along a second axis at a predetermined speed, a measuring instrument that measures the shape of tooth traces cut on the outer periphery of the work while the work is fixed to the work table, And a saddle capable of moving the measuring instrument along a third axis parallel to the second axis.

  Preferably, in the present invention, the processing apparatus rotates the work fixed on the work table at a predetermined rotation speed around the first axis, and the cutter is moved along the second axis at a predetermined propulsion speed. While reciprocating, the cutter is controlled to form a tooth streak on the outer periphery of the workpiece at a cutting position shallower than the tooth to be finally formed, and the workpiece is fixed in the work table and formed in the primary processing step. The measuring instrument is controlled to measure the shape of the tooth streak, and the cutting error of the tooth streak is calculated based on the measurement result obtained in the measurement process and the set value of the tooth streak to be formed in the primary processing. The set value of the tooth trace is corrected based on the calculated error, the work fixed to the work table is rotated around the first axis based on the corrected set value of the tooth streak in the correction process, and the cutter The While reciprocating along two axes, further comprising a control device for controlling the cutter as cutting a tooth trace to a depth of tooth height to be finally formed on the workpiece which is secured to the work table.

  As described above, according to the present invention, a highly accurate helical gear can be processed from the beginning.

It is a perspective view of the gear shaper by the embodiment of the present invention. It is a principal part perspective view which shows the structure in the cutter head of the gear shaper by embodiment of this invention. It is a sectional side view which shows the principal part of the column and cutter head of the gear shaper by embodiment of this invention. It is a top view of the work table of the gear shaper by embodiment of this invention. It is a sectional side view of the cutter head of the gear shaper by embodiment of this invention. It is sectional drawing of the VI-VI cross section of FIG. It is a side view which shows the contact-type measuring device of the gear shaper by embodiment of this invention. It is a flowchart which shows the manufacturing process of the helical gear by the gear shaper by embodiment of this invention. It is a perspective view which shows the measuring element of the dial gauge in the measurement process of the processing method by embodiment of this invention. It is a side view which shows the tooth trace formed in the outer periphery of the workpiece | work by the primary process of the processing method by embodiment of this invention, and a continuous line reflects the influence of the cutting error on a tooth trace.

  Hereinafter, a helical gear machining method and machining apparatus according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a perspective view of a gear shaper as a processing apparatus. As shown in FIG. 1, the gear shaper 1 includes a bed 3 as a base material of the apparatus, a column 5 supported so as to be reciprocally movable on the bed 3 (X-axis direction), and a rotating shaft (C And a work table 7 supported so as to be rotatable about an axis). The column 5 includes a saddle 9 that is supported so as to be reciprocally movable (in the Z-axis direction) along an axis parallel to the C-axis. The saddle 9 supports a cutter head 13 having a cutter 11 for cutting the workpiece W fixed on the work table 7. The cutter 11 is supported by the saddle 9 so as to reciprocate along an axis (Y-axis direction) parallel to the rotation axis of the work table 7. Moreover, although mentioned later for details, the gear shaper 1 is provided with the contact-type measuring device for measuring the error when cutting a workpiece | work.
The C axis described above corresponds to the “first axis” in the present invention, the Y axis corresponds to the “second axis”, and the Z axis corresponds to the “third axis”.

  FIG. 2 is a perspective view of the main part showing the configuration inside the cutter head, FIG. 3 is a side sectional view showing the main part of the column of the gear shaper and the cutter head, and FIG. 4 is a top view of the work table. .

  A main shaft 17 is supported on the cutter head 13 so as to be rotatable (around the Y axis) and movable in the axial direction. A driven gear 19 is provided on the main shaft 17, and a driving gear 21 is engaged with the driven gear 19. The drive gear 21 is driven by the Y-axis motor 23, and the main shaft 17 rotates in a predetermined state via the drive gear 21 and the driven gear 19 by the drive of the Y-axis motor 23.

  The upper end portion of the main shaft 17 is connected to the lower end of the connecting rod 25 via a spherical bearing, and the upper end portion of the connecting rod 25 is supported by the crank mechanism 27. The crank mechanism 27 is rotationally driven by the drive of the main shaft motor 15, and the main shaft 17 reciprocates in the vertical direction via the connecting rod 25 by the rotational drive of the crank mechanism 27. The driving force of the spindle motor 15 is transmitted to the cam mechanism 29, and the cutter head 13 moves the cam mechanism 29 according to the driving state of the spindle motor 15, that is, according to the reciprocating state of the spindle 17 in the vertical direction. Swings through. A pinion cutter 11 is attached to the tip of the main shaft 17, and the cutter 11 rotates in a predetermined state by driving the Y-axis motor 23 and reciprocates in the vertical direction by driving the main shaft motor 15.

  The workpiece W is mounted on the workpiece table 7, and the workpiece W is rotated in a predetermined state by driving the C-axis motor 31. The workpiece W is processed by the cutter 11 by the rotation of the work table 7, the rotation of the main shaft 17, and the reciprocating motion in the vertical direction. The cutter 11 is reciprocated in the vertical direction by the drive of the spindle motor 15, and at the same time, the cutter 11 is rotated (synchronously rotated) in synchronism with the rotation of the workpiece W by the drive of the Y-axis motor 23, and the torsion angle of the workpiece W (helical) Rotation according to (angle) is added to the synchronous rotation (combined rotation). Further, when the main shaft 17 is lowered, the cutter 11 is engaged with the workpiece W and machining is performed. When the main shaft 17 is raised, the cutter head 13 is swung via the cam mechanism 29 and the cutter 11 and the workpiece W are moved. And the meshing is released.

  Synchronous rotation with respect to the workpiece W and rotation according to the torsion angle of the workpiece W are synthesized and performed simultaneously by the Y-axis motor 23. The combined rotation of the main shaft 17 by the Y-axis motor 23 is controlled by the control device, and the control device calculates the rotation locus of the main shaft 17 during the combined rotation and outputs a drive command to the Y-axis motor 23.

  As shown in FIG. 4, the work table 7 includes a C-axis motor 31, and the work table 7 is rotated by the C-axis motor 31 via a worm 33 and a worm wheel 35.

  FIG. 5 is a sectional side view of the cutter head, and FIG. 6 is a sectional view taken along the line VI-VI in FIG. As shown in FIGS. 5 and 6, the cutter 11 is attached to the lower end portion of the main shaft 17, and the main shaft 17 is slidably guided in the axial direction and the rotational direction via a bearing 37 fitted to the cutter head 13. Has been. A male shape 39 is fitted to the upper portion of the main shaft 17, and a convex spline 41 extending in the axial direction (vertical direction) is formed on the outer peripheral surface of the male shape 39. A guide cylinder 43 is disposed outside the male 39, and a concave groove 45 extending in the axial direction (vertical direction) is formed on the inner peripheral surface of the guide cylinder 43. The male 39 is guided in the guide cylinder 43 through the spline 41 and the groove of the guide cylinder 43 so as to be slidable in the vertical direction. The guide cylinder 43 is rotatably supported by the cutter head 13 via a bearing 47, and the driven gear 19 is fixed to the upper part of the guide cylinder 43.

  The cutter head 13 is provided with a Y-axis motor 23, and a drive gear 21 (not shown) of the Y-axis motor 23 is engaged with the driven gear 19. By driving the Y-axis motor 23, the main shaft 17 is rotated along the rotation locus of the composite rotation described above via the driven gear 19, the guide cylinder 43 and the male shape 39.

  On the other hand, a housing 49 is fitted on the upper part of the male 39, and a spherical bearing 51 is supported on the housing 49 so as to be rotatable and swingable. The spherical bearing 51 is connected to the lower end of the feed screw shaft 53, and the axial position of the threaded portion 55 of the feed screw shaft 53 is fixed in a state where it is screwed into the knuckle 57. The knuckle 57 is rotatably supported on the rotating disk 59 side of the crank mechanism 27, and the main shaft 17 is vertically moved through the knuckle 57, the feed screw shaft 53, the spherical bearing 51, the housing 49, and the male 39 by the rotation of the rotating disk 59. Reciprocate. That is, the connecting rod 25 is constituted by the knuckle 57 and the feed screw shaft 53.

  By rotating the rotating disk 59 by driving the spindle motor 15 not shown in FIG. 5, the spindle 17 reciprocates in the vertical direction via the connecting rod 25 and the spherical bearing 23. At this time, the male 39 is slidably guided in the guide cylinder 43 through the spline 41 and the groove 45 of the guide cylinder 43, so that the main shaft 17 reciprocates in the vertical direction. By the combined rotation of the main shaft 17 driven by the Y-axis motor 23 and the reciprocating movement of the main shaft 17 driven by the main shaft motor 15, the cutter 11 performs processing on the workpiece W.

  The cutter head 13 and the cutter 11 are held in a saddle 9 that can reciprocate in the Z-axis direction with respect to the column 5. The saddle 9 is configured to reciprocate in the Z-axis direction with respect to the column 5 so that the positions of the cutter head 13 and the cutter 11 in the Z-axis direction can be adjusted with respect to the work table 7. When the positions of the cutter head 13 and the cutter 11 with respect to the work table 7 are determined, the saddle 9 is fixed to the column 5 at the time of processing. That is, the saddle 9 does not contribute at all to the machining operation including the movement of the cutter 11 in the Y-axis direction during machining, and the Z-axis is used to fix the positions of the cutter head 13 and the cutter 11 with respect to the work table 7. It is formed to be movable in the direction.

  FIG. 7 is a side view showing a contact-type measuring instrument. The contact-type measuring instrument is constituted by a dial gauge 61 fixed to the lower surface of the saddle 9. The dial gauge 61 has a measuring element 63 and a scale plate 65 fixed to the lower surface of the saddle 9 by an arm 67. The dial gauge 61 can take a measurement posture in which the probe 63 can come into contact with the outer periphery of the workpiece W and a retracting posture in which the measuring member 63 is retracted to a position that does not interfere with cutting by the cutter 11. When measuring the shape of the tooth trace using the dial gauge 61, the probe 63 of the dial gauge 61 is disposed between the tooth traces formed on the workpiece W, and the shape of the tooth trace is determined in the length direction of the tooth trace. This is done by measuring multiple locations across the network. A specific measurement method will be described later.

  In FIG. 7, a dial gauge 61 is taken as an example of a contact-type measuring instrument. However, as means for measuring the shape of the tooth trace in the present invention, the shape of the tooth trace is measured by the user's hand. In addition to the dial gauge, a contact sensor is attached to the tip of an arm fixed to the gear shaper 1 so that the detected value of this sensor can be transmitted to the gear shaper 1 so that the shape of the tooth trace can be automatically measured by the gear shaper 1. It may be. In addition, as a measuring instrument, a tooth trace formed on the outer periphery of the workpiece W may be scanned with a laser so that the shape of the tooth trace can be measured by image analysis processing.

  FIG. 8 is a flowchart showing the machining process of the elliptical gear by the gear shaper. First, after a work is fixed to the work table 7 of the gear shaper 1, the user operates the user device in step S1, calls a machining program for the gear shaper 1, and a series of processes starts.

  Next, in step S <b> 2, the user inputs a set value of the tooth trace to be formed on the workpiece W to the user device. The set value of the tooth trace is a value relating to the twist angle of the workpiece W for realizing the tooth trace to be formed immediately after the machining, the rotation starting position of the spindle 17 at the time of machining, or the like. The set value of the tooth streak inputted at this time has the inclination angle and width of the helical gear to be finally formed, that is, the tooth streak that the product helical gear should have, and is finally formed. A value is set such that the tooth streak is formed at a cutting position whose depth is shallower than the toothpick that the helical gear to have. The value input to the user device is transmitted to the gear shaper 1.

  Next, in step S <b> 3, the gear shaper 1 performs primary processing based on the set value of the tooth trace received from the user device. When primary processing is performed, the gear shaper 1 calculates the optimum driving speed of the cutter 11 and the work table 7 based on the received set value of the tooth trace, and based on the calculated value, the work shape of the work fixed to the work table 7 is calculated. Tooth lines are formed on the entire circumference.

  Next, in step S4, the shape of the tooth trace is measured.

  FIG. 9 is a perspective view showing a dial gauge probe in the measurement process. As shown in FIG. 9, when the measuring instrument is a manual measuring instrument such as a dial gauge, the user first sets the measuring element 63 of the dial gauge 61 while keeping the work W fixed to the work table 7. The dial gauge 61 is adjusted so that the scale of the dial gauge 61 becomes 0 by contacting the upper end wall. Then, the user drives the saddle 9 of the gear shaper 1 and the work table 7 synchronously based on the set value of the tooth trace used in the primary processing. As described above, the saddle 9 is fixed to the column 5 during primary processing, and is also fixed relatively to the work table 7. Therefore, the saddle 9 does not contribute to the primary processing, and the movement of the saddle 9 in the Z-axis direction and the rotation of the work table 7 around the C-axis are controlled separately. Therefore, in the measurement process, the movement of the saddle 9 in the Z-axis direction and the rotation of the work table 7 around the C-axis are synchronized, and the saddle 9 reproduces the reciprocating movement of the cutter 11 in the Y-axis direction during primary processing. By causing the work table 7 to reproduce the rotation of the work table 7 at the time of primary processing, the tracing stylus 63 of the dial gauge 61 is caused to reproduce the movement locus of the cutter 11 in a pseudo manner. If the tooth trace is accurately reproduced based on the set value of the tooth trace at the time of primary processing, the probe 63 of the dial gauge 61 reproduces the movement locus based on the set value of the tooth trace at the time of primary processing. The scale of the dial gauge 61 should not move from zero. However, when there is an error between the set value at the time of the primary processing and the tooth trace actually formed by the primary processing, the measuring element 63 contacts the wall of the tooth trace, so that the cutting error is indicated on the scale plate 65 of the dial gauge 61. Can be read from. Therefore, by setting the dial gauge 61 to the saddle 9 that does not contribute to the primary machining and measuring the tooth trace, the set value of the primary trace of the primary machining and the cutting error of the tooth trace actually formed by the primary machining are obtained. Can be calculated.

  When the gear shaper 1 includes an automatic measuring instrument, the gear shaper 1 performs the vertical movement of the saddle 9 and the rotational movement of the work table 7 based on a program stored in the gear shaper 1 in advance at the end of the primary processing. After that, the measuring element of the measuring instrument is moved to the measuring point to measure the shape of the tooth trace.

  In the present embodiment, the measuring instrument is fixed to the saddle 9, but the member that fixes the measuring instrument is a member that does not contribute to the primary processing and is movable in the Z-axis direction by the control of the gear shaper 1. Any member may be used, and a measurement saddle 9 may be separately provided at a position away from the column 5.

  Next, in step S5, a cutting error is calculated by comparing the measurement result with the set value of the primary processing tooth trace, and it is determined whether or not the cutting error is within an allowable range. This determination is made when the measuring instrument is manual, the user visually observes the measurement result of the measuring instrument and inputs the measurement result to the user device, and the user device compares the measurement result with a predetermined allowable value. To do. On the other hand, when the measuring instrument is automatic, the gear shaper 1 compares the measurement result with an allowable value stored in advance in the gear shaper 1.

  If the measurement result exceeds the allowable error range, the setting value of the tooth streak is corrected in step S6.

  FIG. 10 is a side view showing the tooth traces formed on the outer periphery of the workpiece by the primary processing. In FIG. 10, a solid line indicates a tooth line actually formed by primary processing, and a broken line indicates a tooth line that should have been formed based on a set value of the tooth line at the time of primary processing. As shown in (a), for example, when the inclination angle of the formed tooth stripe is deviated from the inclination angle of the tooth stripe to be formed, the twist angle of the workpiece W is corrected. Thereby, the inclination angle of the tooth trace can be corrected. Further, as shown in (b), when irregularities are found in the tooth line formed by the primary processing, the rotation starting position of the main shaft 17 is corrected.

  Then, after correcting the set value of the tooth streak in step S6, the processes of steps S2 to S4 are repeated again, and the correction of the set value of the tooth streak is repeated in step S6 until the cutting error is within the allowable range.

  Thereafter, when it is determined in step S5 that the cutting error is within the allowable range, the final set value of the tooth trace for realizing the depth of the tooth to be finally formed in step S7 is stored in the user device. Enter. Then, the final set value of the tooth trace is transmitted to the gear shaper 1, and in step S8, the gear shaper 1 performs the secondary processing based on the final set value of the tooth trace and ends a series of processes.

  As described above, according to the present embodiment, the tooth trace is experimentally formed at the shallow cutting position with respect to the first workpiece W, and the set value of the tooth trace is determined based on the measurement result of the formed tooth trace. Correction is made. Therefore, according to this embodiment, a highly accurate helical gear can be machined from the first workpiece.

1 Gear shaper 7 Work table 9 Saddle 11 Cutter 61 Dial gauge

Claims (6)

The workpiece is rotated around the first axis, and the cutter is brought into contact with the outer peripheral surface of the workpiece while moving the cutter along a second axis parallel to the first axis. A helical gear machining method for cutting tooth traces,
The work fixed on the work table is finally formed while rotating at a predetermined rotational speed around the first axis and reciprocating the cutter along the second axis at a predetermined propulsion speed. A primary processing step of forming a streak on the outer periphery of the workpiece at a cutting position shallower than the toothpick to be done;
A measurement step of measuring the shape of the tooth trace formed in the primary processing step while fixing the workpiece to the work table;
Calculate the tooth streak cutting error based on the measurement result obtained in the measuring step and the set value of the tooth streak to be formed in the primary processing, and correct the set value of the tooth streak based on the calculated error. A correction process to
While rotating the work fixed to the work table around the first axis based on the set value of the tooth trace corrected in the correction step, and reciprocating the cutter along the second axis, And a secondary processing step of cutting the tooth trace to the depth of the tooth trace to be finally formed on the work fixed to the work table. In the measurement step, a contact-type measuring instrument fixed to a saddle, which is movable along a third axis parallel to the second axis and does not contribute to the primary processing step, is prepared. The tooth trace is measured by bringing the measuring element of the measuring instrument into contact with the tooth trace cut in the primary machining step, and the saddle and the work table are driven synchronously based on the target value of the tooth trace,
The processing method according to claim 1, wherein in the correction step, a cutting error is calculated based on a difference between a set value of a tooth line to be formed in the primary processing and a measurement result obtained in the measurement step.   The processing according to claim 1, wherein in the measuring step, the shape of the tooth streak formed in the primary processing step is automatically measured by scanning a workpiece on which the tooth streak has been cut in the primary processing step with a laser. Method.   The processing method according to any one of claims 1 to 3, wherein the secondary processing step is performed after the primary processing step, the measurement step, and the correction step are repeated a plurality of times. The workpiece is rotated around the first axis, and the cutter is brought into contact with the outer peripheral surface of the workpiece while moving the cutter along a second axis parallel to the first axis. A helical gear machining device that cuts tooth traces,
The work table is fixed, and the work table for rotating the fixed work around the first axis at a predetermined rotation speed;
A cutter head for reciprocating the cutter along the second axis at a predetermined speed;
A measuring instrument that measures the shape of the tooth traces cut on the outer periphery of the work while the work is fixed to the work table;
A processing apparatus comprising: a saddle on which the measuring instrument is fixed, and the measuring instrument can be moved along a third axis parallel to the second axis. The work fixed on the work table is finally formed while rotating at a predetermined rotational speed around the first axis and reciprocating the cutter along the second axis at a predetermined propulsion speed. Controlling the cutter head so as to form a streak on the outer periphery of the workpiece at a cutting position shallower than the toothpick to be made,
Controlling the measuring instrument to measure the shape of the tooth trace formed in the primary processing step while fixing the work to the work table;
Calculate the tooth streak cutting error based on the measurement result obtained in the measuring step and the set value of the tooth streak to be formed in the primary processing, and correct the set value of the tooth streak based on the calculated error. And
While rotating the work fixed to the work table around the first axis based on the set value of the tooth trace corrected in the correction step, and reciprocating the cutter along the second axis, The control unit according to claim 5, further comprising a control unit that controls the cutter so as to cut a tooth streak to a depth of a tooth to be finally formed on the work fixed to the work table. Processing equipment.

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