JP7413794B2 - Gear processing equipment and gear processing method - Google Patents

Description

The present invention relates to a gear processing device and a gear processing method.

Transmissions used in vehicles are provided with a synchromesh mechanism for smooth gear shifting operations. As shown in FIG. 11, the key type synchromesh mechanism 110 includes a main shaft 111, a main drive shaft 112, a clutch hub 113, a key 114, a sleeve 115, a main drive gear 116, a clutch gear 117, a synchronizer ring 118, etc. Be prepared.

The main shaft 111 and the main drive shaft 112 are coaxially arranged. A clutch hub 113 is spline-fitted to the main shaft 111, and the main shaft 111 and the clutch hub 113 rotate together. A key 114 is supported at three locations on the outer periphery of the clutch hub 113 by springs (not shown). Internal teeth (splines) 115a are formed on the inner circumference of the sleeve 115, and the sleeve 115 slides in the direction of the rotation axis LL along the splines (not shown) formed on the outer circumference of the clutch hub 113 together with the key 114.

A main drive gear 116 is fitted into the main drive shaft 112, and a clutch gear 117 having a protruding taper cone 117b is integrally formed on the sleeve 115 side of the main drive gear 116. A synchronizer ring 118 is arranged between the sleeve 115 and the clutch gear 117. External teeth 117a of clutch gear 117 and external teeth 118a of synchronizer ring 118 are formed to be able to mesh with internal teeth 115a of sleeve 115. The inner periphery of the synchronizer ring 118 is formed into a tapered shape that can be frictionally engaged with the outer periphery of the taper cone 117b.

Next, the operation of the synchromesh mechanism 110 will be explained. As shown in FIG. 12A, by operating a shift lever (not shown), the sleeve 115 and the key 114 move in the direction of the rotation axis LL indicated by the arrow in the drawing. The key 114 pushes the synchronizer ring 118 in the direction of the rotation axis LL, pressing the inner circumference of the synchronizer ring 118 against the outer circumference of the taper cone 117b. As a result, clutch gear 117, synchronizer ring 118, and sleeve 115 start synchronous rotation.

As shown in FIG. 12B, the key 114 is pushed down by the sleeve 115 and further presses the synchronizer ring 118 in the direction of the rotation axis LL, so that the inner periphery of the synchronizer ring 118 and the outer periphery of the taper cone 117b are in close contact with each other. increases. As a result, a strong frictional force is generated, and the clutch gear 117, synchronizer ring 118, and sleeve 115 rotate synchronously. When the rotational speed of the clutch gear 117 and the rotational speed of the sleeve 115 are completely synchronized, the frictional force between the inner circumference of the synchronizer ring 118 and the outer circumference of the taper cone 117b disappears.

Then, when the sleeve 115 and the key 114 move further in the direction of the rotation axis LL shown by the arrow, the key 114 fits into the groove 118b of the synchronizer ring 118 and stops, but the sleeve 115 moves beyond the protrusion 114a of the key 114. The inner teeth 115a of the sleeve 115 mesh with the outer teeth 118a of the synchronizer ring 118. Then, as shown in FIG. 12C, the sleeve 115 further moves in the direction of the rotation axis LL indicated by the arrow in the figure, and the internal teeth 115a of the sleeve 115 mesh with the external teeth 117a of the clutch gear 117. Through the above steps, the gear shift is completed.

In the synchromesh mechanism 110 as described above, in order to prevent the gear from coming off between the external teeth 117a of the clutch gear 117 and the internal teeth 115a of the sleeve 115 during running, as shown in FIGS. The tooth 115a is provided with a tapered gear dislodgement prevention portion 120, and the external tooth 117a of the clutch gear 117 is provided with a tapered gear dislodgement prevention portion (not shown) that taper-fits with the gear dislodgement prevention portion 120. It will be done. In the following description, the left side surface 115A of the internal teeth 115a of the sleeve 115 is referred to as the left side surface 115A, and the right side surface 115B of the internal teeth 115a of the sleeve 115 is referred to as the right side surface 115B.

The left side surface 115A of the internal tooth 115a of the sleeve 115 includes a left tooth surface 115b, a tooth surface 121 (hereinafter referred to as left tapered tooth surface 121) having a different helix angle from this left tooth surface 115b, and a tooth surface 131. (hereinafter referred to as a left chamfer tooth surface 131). The right side surface 115B of the internal tooth 115a of the sleeve 115 includes a right tooth surface 115c, a tooth surface 122 (hereinafter referred to as right tapered tooth surface 122) having a different helix angle from this right tooth surface 115c, and a tooth surface 132. (hereinafter referred to as a right chamfer tooth surface 132).

In the conventional example described above, the helix angle of the left tooth flank 115b is 0 (zero), the helix angle of the left tapered tooth flank 121 is θf, and the helix angle of the left chamfer tooth flank 131 is θL. Further, the helix angle of the right tooth flank 115c is 0 (zero), the helix angle of the right tapered tooth flank 122 is θr, and the helix angle of the right chamfer tooth flank 132 is θR. Then, the left tapered tooth surface 121, the tooth surface 121a connecting the left tapered tooth surface 121 and the left tooth surface 115b (hereinafter referred to as the left sub-tooth surface 121a), the left chamfer tooth surface 131, and the right tapered tooth surface 122. , a tooth surface 122a connecting the right tapered tooth surface 122 and the right tooth surface 115c (hereinafter referred to as the right sub-tooth surface 122a), and the right chamfer tooth surface 132 constitute the gear slippage prevention section 120. Note that prevention of gear disengagement is achieved by tapered fitting between the left tapered tooth surface 121 and the gear disengagement prevention portion of the clutch gear 117. Further, the left chamfer tooth surface 131 and the right chamfer tooth surface 132 are for smooth engagement with the gear disengagement prevention portion of the clutch gear 117.

As described above, the structure of the internal teeth 115a of the sleeve 115 is complicated, and in order to reliably prevent the gear from coming off as described above, it is necessary to machine the gear coming off prevention portion 120 with high precision. For this reason, gear machining devices and gear machining methods capable of machining tooth surfaces with high precision have been known as disclosed in Patent Documents 1 and 2 below. Further, the sleeve 115 is a component that requires mass production. For this reason, as disclosed in Patent Document 3 below, it has been conventionally possible to increase the length of the machining tool by changing the phase of the machining tool for each machining process in a machining tool equipped with a plurality of blades. Gear machining methods that can extend the life of gears are also known.

JP2019-018335A JP2018-079558A Japanese Patent Application Publication No. 2018-001343

By the way, when machining the gear slip-out prevention portion 120 of the internal teeth 115a of the sleeve 115 with high precision, it is necessary to machine the gear using a plurality of different machining tools depending on the part to be machined and the content of the process. In this case, after the blade position of the machining tool is aligned with the tooth phase of the workpiece such as the sleeve 115, or after the tooth position of the workpiece is aligned with the blade phase of the machining tool, the workpiece is cut. The next machining must be performed after determining the reference rotation angle for this purpose. However, in a series of machining, if the tooth phase of the workpiece or the blade phase of the machining tool is measured every time machining is completed to determine the reference rotation angle, a measuring device is required, and the cycle required for machining is The problem arises that the time increases.

The present invention provides a gear machining device and a gear machining method that can easily determine a reference rotation angle and perform the next machining without measuring the tooth phase of a workpiece, even when using a plurality of machining tools. The purpose is to

One aspect of the present invention is
A gear processing device that generates a plurality of teeth by cutting a peripheral surface of the workpiece by rotating a processing tool synchronously with the workpiece and relatively feeding the workpiece in the direction of the rotational axis of the workpiece, the gear processing device comprising:
a workpiece rotation drive device that rotationally drives the workpiece with a reference state in which the detected value of the rotation angle is a predetermined value;
A control device that controls the relative position of the processing tool and the workpiece,
The control device includes:
As a machining preparation step, the machining tool is located at an approach position spaced apart from the workpiece in the direction of the rotation axis,
As the machining preparation step, at the approach position, the rotational position of the tool blade of the machining tool is positioned at a predetermined tool blade position corresponding to the position of the tooth groove already formed on the peripheral surface of the workpiece,
As the machining preparation step, the already formed tooth groove is moved to a predetermined tooth groove position based on the approach position of the machining tool and the predetermined tool blade position of the tool blade of the machining tool at the approach position. Determine a reference rotation angle that is the rotation angle of the workpiece rotation drive device when the workpiece rotation drive device is located at
As the machining preparation step, in order to position the already formed tooth groove at the predetermined tooth groove position, the rotation angle of the workpiece rotation drive device is positioned at the reference rotation angle,
As a machining step following the machining preparation step, the machining tool is relatively sent from the approach position in the direction of the rotation axis of the workpiece, and the machining tool is rotated in synchronization with the workpiece. , the gear processing apparatus cuts the teeth forming the tooth grooves of the workpiece that have already been formed.
Further, other aspects of the present invention include:
A gear that cuts the circumferential surface of the workpiece by rotating a processing tool synchronously with the workpiece and relatively feeding it in the direction of the rotational axis of the workpiece, thereby creating a plurality of teeth on the circumferential surface. A processing method,
a workpiece rotation drive device that rotationally drives the workpiece with a reference state in which the detected value of the rotation angle is a predetermined value;
using a control device that controls the relative position of the processing tool and the workpiece,
By the control device,
As a machining preparation step, the machining tool is located at an approach position spaced apart from the workpiece in the direction of the rotation axis,
As the machining preparation step, at the approach position, the rotational position of the tool blade of the machining tool is positioned at a predetermined tool blade position corresponding to the position of the tooth groove already formed on the peripheral surface of the workpiece,
As the machining preparation step, the already formed tooth groove is moved to a predetermined tooth groove position based on the approach position of the machining tool and the predetermined tool blade position of the tool blade of the machining tool at the approach position. Determine a reference rotation angle that is the rotation angle of the workpiece rotation drive device when located at
As the machining preparation step, in order to position the already formed tooth groove at the predetermined tooth groove position, the rotation angle of the workpiece rotation drive device is positioned at the reference rotation angle,
As a machining process following the machining preparation process, the machining tool is relatively sent from the approach position in the direction of the rotation axis of the workpiece, and the machining tool is rotated synchronously with the workpiece. , the gear processing method includes cutting the teeth that form the tooth grooves of the workpiece that have already been formed.

According to the above aspect , even when a plurality of machining tools are used, there is no need to measure the tooth phase of the workpiece to be cut each time, and the reference rotation angle can be quickly determined to perform the next machining. Can be done. Therefore, a measuring device for measuring the phase is not required, and the cycle time required for processing can be shortened.

FIG. 1 is a diagram showing the overall configuration of a gear processing device. FIG. 2 is a diagram showing the configuration of the tool changing device shown in FIG. 1. FIG. FIG. 2 is a partial cross-sectional view showing the configuration of a processing tool (skiving cutter). FIG. 3 is a diagram for explaining a predetermined rotational position of a processing tool. It is a figure for explaining the top position of a workpiece. It is a figure for explaining the top shape of a processing tool at a predetermined rotational position. FIG. 3 is a diagram for explaining a reference rotation angle. It is a figure for explaining the correction amount when cutting a taper tooth surface. It is a figure for explaining the correction amount when cutting a chamfer tooth surface. It is a table showing processing conditions when cutting the gear slippage prevention part of the sleeve. It is a figure for explaining the state in which the tooth surface (tooth groove) of a sleeve is cut by skiving processing. It is a figure which shows the relationship between the rotation speed of the processing tool and the rotation speed of the sleeve when cutting the sleeve by skiving processing, and shows the top shape of the processing tool and the top position of the sleeve at the start of processing. It is a flowchart showing the process of machining a sleeve, which is a workpiece. FIG. 2 is a sectional view showing a synchromesh mechanism having a sleeve as a workpiece. FIG. 12 is a sectional view showing a state before the synchromesh mechanism of FIG. 11 starts operating. FIG. 12 is a cross-sectional view showing the synchromesh mechanism of FIG. 11 in operation. FIG. 12 is a sectional view showing a state of the synchromesh mechanism of FIG. 11 after completion of operation. FIG. 2 is a perspective view showing a gear slippage prevention portion of a sleeve, which is a workpiece. FIG. 14 is a radial view of the gear slip-off prevention portion of the sleeve in FIG. 13;

(1. Mechanical configuration of gear processing equipment)
In this example, a five-axis machining center capable of skiving processing will be taken as an example of a gear processing device. Specifically, as shown in FIG. 1, the gear processing device 1 of this example has three linear axes (X-axis, Y-axis, Z-axis) and two rotation axes (X-axis) that are orthogonal to each other as drive axes. The device has an A-axis parallel to the A-axis and a C-axis perpendicular to the A-axis.

As shown in FIG. 1, the gear processing device 1 includes a bed 10, a column 20, a saddle 30, a rotating main shaft 40, a table 50, a tilt table 60, and a turntable 70 as a workpiece rotation drive device. , a workpiece holding device 80, a tool changing device 90, and a control device 100.

The bed 10 is formed into a substantially rectangular shape and is placed on the floor. An X-axis ball screw (not shown) is arranged on the top surface of the bed 10 to drive the column 20 in a direction parallel to the X-axis. An X-axis motor 11c that rotationally drives an X-axis ball screw is arranged on the bed 10.

A Y-axis ball screw (not shown) for driving the saddle 30 in a direction parallel to the Y-axis is arranged on a side surface (sliding surface) 20a of the column 20 that is parallel to the Y-axis. A Y-axis motor 23c that rotationally drives a Y-axis ball screw is arranged in the column 20.

The rotating main shaft 40 supports a processing tool 42, is rotatably supported within the saddle 30, and is rotated by a main shaft motor 41 housed within the saddle 30. The processing tool 42 is held by a tool holder 43 and fixed to the tip of the rotating main shaft 40, and rotates as the rotating main shaft 40 rotates. Further, the processing tool 42 moves in a direction parallel to the X-axis and in a direction parallel to the Y-axis with respect to the bed 10 as the column 20 and saddle 30 move. Note that details of the processing tool 42 will be described later.

Furthermore, a Z-axis ball screw (not shown) is arranged on the top surface of the bed 10 to drive the table 50 in a direction parallel to the Z-axis. A Z-axis motor 12c that rotationally drives a Z-axis ball screw is arranged on the bed 10.

A tilt table support section 63 that supports the tilt table 60 is provided on the upper surface of the table 50. The tilt table 60 is provided in the tilt table support section 63 so as to be rotatable (swingable) around an axis parallel to the A axis. The tilt table 60 is rotated (swung) by an A-axis motor 61 housed within the table 50.

A turntable 70 serving as a workpiece rotation drive device is provided on the tilt table 60 so as to be rotatable around an axis parallel to the C-axis. A workpiece holding device 80 that constitutes a workpiece main shaft that holds a sleeve 115, which is a workpiece, is attached to the turntable 70. The turntable 70 is rotated by the C-axis motor 62 together with the sleeve 115 and the workpiece holding device 80 . Here, the turntable 70 is provided with an encoder 71 that detects the rotation angle around the C-axis. The reference state of the turntable 70 is, for example, set to a state where the rotation angle detected by the encoder 71 is 0 degrees.

Next, as specifically shown in FIG. 2, the tool changing device 90 will be explained. The tool exchange device 90 exchanges the machining tool 42 mounted on the rotating main shaft 40 with another machining tool 42 housed in the tool magazine M. Here, the tool magazine M accommodates a plurality of machining tools 42. In addition, in FIG. 2, in order to simplify the drawing, only three processing tools 42 (processing tools 42A, 42B, and 42C, which will be described later) are illustrated. A plate-shaped support plate 13 is fixed to the upper surface of the bed 10, and a tool magazine M is rotatably provided on the support plate 13.

The tool exchange device 90 includes a device main body 91, an exchange arm 92, an arm motor 93, a frame portion 94, a door 95, a moving body 96, a tool holding portion 97, a detection portion 98, and a tool exchange control unit. 99. Here, the tool exchange control section 99 is connected to a control device 100, which will be described later, to share data. The device main body 91, exchange arm 92, arm motor 93, frame 94, door 95, moving body 96, and tool holder 97 are well known, and for example, refer to Japanese Patent Laid-Open No. 2018-103330. Since it is possible to do so, its explanation will be omitted.

The detection unit 98 detects the rotational position of the machining tool 42 mounted on the rotating main shaft 40. The detection unit 98 detects the rotational position of the processing tool 42 by, for example, detecting a detected portion provided on the processing tool 42 or the tool holder 43. Here, as the detection unit 98, a non-contact type eddy current sensor, a contact type touch probe sensor, etc. can be used. As shown in FIG. 2, the detection part 98 is held by a detection part arm, and when the detection arm extends, it approaches the detected part, and the processing part attached to the rotating main shaft 40 The rotational position of the tool 42 is detected. Here, the rotational position detected by the detection unit 98 is stored in a storage unit 104 of the control device 100, which will be described later. Note that regarding detection of the rotational position of the processing tool 42, reference may be made to, for example, Japanese Patent Laid-Open No. 2013-129000.

As shown in FIG. 1, the control device 100 mainly includes a processing control section 101, a reference rotation angle determining section 102, a processing position calculation section 103, and a storage section 104. Here, the processing control section 101, the reference rotation angle determining section 102, the processing position calculation section 103, and the storage section 104 may each be configured by separate computer hardware (CPU, memory, storage, etc.), or may be configured by computer software. (data, programs, etc.) may be implemented.

The machining control unit 101 controls the spindle motor 41 to rotate the machining tool 42 . The processing control unit 101 also controls the X-axis motor 11c, the Z-axis motor 12c, the Y-axis motor 23c, the A-axis motor 61, and the C-axis motor 62. As a result, the machining control unit 101 moves the workpiece sleeve 115 and the machining tool 42 in a direction parallel to the X-axis, a direction parallel to the Z-axis, a direction parallel to the Y-axis, and a direction parallel to the A-axis around the axis. The sleeve 115 is cut by relative movement around an axis parallel to the C-axis and the C-axis.

The reference rotation angle determining unit 102 acquires the rotation angle of the turntable 70, that is, the sleeve 115, from the encoder 71 of the turntable 70, and stores it in the storage unit 104 or the like. Further, the reference rotation angle determining unit 102 acquires the rotational position of the tool blade 42a of the processing tool 42 from the detection unit 98 of the tool changer 90, and stores it in the storage unit 104 or the like. The reference rotation angle determining unit 102 is arranged at a position where the processing tool 42 is spaced apart from the sleeve 115 in the direction of the C axis (rotation axis) (hereinafter referred to as approach position U1), and at the approach position U1. Based on the predetermined rotational position that is the rotational position of the tool blade 42a acquired from the detection unit 98, the angular position of the tooth groove 115g of the sleeve 115 in the reference state of the turntable 70 is calculated as the reference rotational angle P of the sleeve 115 ( (see Figure 8).

Specifically, as shown in FIG. 5A, the angular position of the tooth groove 115g is, for example, the tooth closest to the vertical line (90 degree line) in the reference state of the turntable 70 when the sleeve 115 is viewed from the C-axis direction. This is the angle representing the deviation between the imaginary straight line connecting the center of the groove 115g and the center of the sleeve 115 and the vertical line. Therefore, the reference rotation angle P is the angle detected by the encoder 71 when the turntable 70 is rotated so that the virtual straight line coincides with the vertical line.

Here, when calculating (determining) the reference rotation angle P, the approach position U1, that is, the distance in the C-axis direction between the processing tool 42 and the sleeve 115 (approach distance M1 to be described later) and the tool of the processing tool 42 are calculated. In addition to the rotational position of the blade 42a, the feed rate at which the processing tool 42 is sent toward the sleeve 115 in the direction of the C-axis, the rotational speed of each of the processing tool 42 and the sleeve 115, etc. can be taken into consideration.

The reference rotation angle P is determined such that, for example, the rotational phase of the machining tool 42 and the sleeve 115 is 0 degrees during synchronous rotation. For example, the reference rotation angle P is determined to be the central angular position of the tooth groove 115g formed by cutting to create the internal teeth 115a of the sleeve 115 (see FIG. 6A).

When cutting tooth surfaces 115b and 115c of the internal teeth 115a of the sleeve 115 that have a helix angle, the machining position calculation unit 103 calculates a position at which cutting is started based on a reference rotation angle P (hereinafter referred to as a cutting position). The starting position U2 (see FIG. 8) is calculated. That is, the machining position calculation unit 103 calculates the correction angle σ representing the cutting start position U2 when the reference rotation angle P is used as a reference, according to the following equation 1.

However, M1 in Equation 1 above represents the approach distance that the processing tool 42 placed at the approach position U1 moves in the direction of the C axis (rotation axis) until it comes into contact with the sleeve 115. Further, θ in the above equation 1 represents the helix angle of the tooth surfaces 115b and 115c of the internal teeth 115a of the sleeve 115 formed by cutting. Further, m in the above formula 1 represents the module of the sleeve 115, and Z represents the number of teeth of the sleeve 115.

In addition, when machining a tooth flank, the machining position calculation unit 103 calculates a temporary machining start position U2d calculated based on the reference rotation angle P, and an actual machining start position U2j when actually machining the tooth flank. Based on the difference, a correction amount σd for correcting the reference rotation angle P is calculated (see FIGS. 6B and 6C).

In this example, the chamfer tooth surfaces 131, 132 (chamfer tooth grooves 131g, 132g) of the gear dislodgement prevention part 120 are provided on the tooth surfaces 115b, 115c (teeth groove 115g) of the internal teeth 115a of the sleeve 115, and the gear dislodgement prevention section 131, 132 (chamfer tooth grooves 131g, 132g). The tapered tooth surfaces 121 and 122 (tapered tooth grooves 121g and 122g) of the portion 120 are cut. In this case, the machining position calculating unit 103 calculates the correction angle σ (correction angles σf, σr, σL, σR) for determining the cutting start position U2 according to Equation 1, and also calculates the correction amount σd for correcting the reference rotation angle P. (see FIGS. 6B, 6C, and 7).

The storage unit 104 stores the number of tool blades 42a (even number or odd number), etc. as tool specification data regarding the processing tool 42. Further, the storage unit 104 stores machining condition data (see FIG. 7) for cutting the sleeve 115, and also stores in advance the number of internal teeth 115a to be created in the sleeve 115 (even number or odd number).

(2. Processing tools)
The processing tool 42 is a skiving cutter, and is designed and manufactured based on the shapes of the left tooth surface 115b and the right tooth surface 115c of the internal tooth 115a. As shown in FIG. 3, the shape of the tool blade 42a of the processing tool 42 is formed to have the same shape as the involute curve shape in this example.

The tool blade 42a of the processing tool 42 is provided with a rake angle that is inclined at an angle γ with respect to a plane perpendicular to the rotational axis L at the cutting edge 42b. Further, the tool blade 42a is provided with a front clearance angle that is inclined by an angle δ with respect to a straight line parallel to the rotational axis L on the tool peripheral surface side. Further, the blade groove 42c of the tool blade 42a has a helix angle that is inclined by an angle β with respect to a straight line parallel to the rotation axis L. Note that the processing tool 42 may include a straight tool blade 42a that does not have the helix angle β and is parallel to the rotation axis L.

(3. Regarding the predetermined rotational position of the processing tool 42)
When cutting the sleeve 115, which is a workpiece, the processing tool 42 is rotated so that the cutting edge 42b or the cutting groove 42c is at a predetermined rotational position based on the relationship shown in FIG. In this example, the machining control unit 101 of the control device 100 controls the cutting edge 42b or the cutting groove 42c of the machining tool 42 at the start of machining, that is, when the machining tool 42 is placed at the approach position U1. Rotate to the specified rotation position.

The predetermined rotational position is determined based on the machining conditions of the workpiece (sleeve 115 in this example) and the tool specifications of the machining tool 42, as shown in FIG. The machining conditions include whether the teeth to be created on the workpiece are internal or external teeth, and whether the number of teeth to be created is an even number or an odd number. The processing conditions in this example are the number of internal teeth 115a of the sleeve 115 (even number or odd number). Further, as the tool specifications, the number of tool blades 42a of the processing tool 42 (even number or odd number) can be mentioned.

In the following description, as shown in FIG. 5A, when the tooth groove 115g of the sleeve 115 is at the top in the first direction, that is, the Y-axis direction (hereinafter, this position will be referred to as the "top position") exemplify. In the following description, as shown in FIG. 5B, the term "tool" refers to the fact that the cutting edge 42b (or cutting groove 42c) of the processing tool 42 is at the top in the Y-axis direction, corresponding to the "top position". A case where the tool top shape is arranged at a predetermined rotational position will be exemplified.

As shown in FIG. 4, the case where the "machining point position" is "up", that is, the first direction, and the tooth groove 115g is formed at the top position of the sleeve 115 in the Y-axis direction will be explained. In this case, in order to form the tooth groove 115g at the top position, the cutting edge 42b of the tool blade 42a of the processing tool 42 needs to come into contact with the sleeve 115. Therefore, as shown in FIG. 5A, when forming the tooth groove 115g at the top position, the number of internal teeth 115a of the sleeve 115 is an even number or an odd number, and the number of tool blades 42a of the processing tool 42 is If the number is even or odd, as shown in FIG. 5B, the cutting edge 42b of the tool blade 42a of the processing tool 42 is placed in a top shape at a predetermined rotational position.

Next, as shown in FIG. 4, when the tooth groove 115g is formed at the top position, the "machining point position" is "down", that is, the second direction opposite to the first direction, and the Y-axis of the sleeve 115 is The case of processing the lowest part in the direction will be explained. In this case, the top shape of the tool blade 42a of the machining tool 42 changes depending on whether the number of internal teeth 115a of the sleeve 115 is an even or odd number, and the shape of the top of the tool blade 42a of the machining tool 42 changes depending on whether the number is even or odd. The tool top shape changes.

Specifically, when the number of internal teeth 115a of the sleeve 115 is an odd number and the tooth groove 115g is formed at the top position, the internal teeth 115a are present at the bottom of the sleeve 115. In this case, the blade groove 42c of the tool blade 42a of the processing tool 42 needs to be located at the lowest part of the sleeve 115. Therefore, when the number of tool blades 42a of the processing tool 42 is an odd number, the top shape of the tool is a blade edge 42b, so that the blade edge 42b is arranged at a predetermined rotational position. Further, in this case, if the number of tool blades 42a of the processing tool 42 is an even number, the top shape of the tool becomes a blade groove 42c, so that the blade groove 42c is arranged at a predetermined rotational position.

Further, when the number of internal teeth 115a of the sleeve 115 is an even number and the tooth groove 115g is formed at the top position, the tooth groove 115g is present at the bottom of the sleeve 115. In this case, the cutting edge 42b of the tool blade 42a of the processing tool 42 needs to be located at the lowest part of the sleeve 115. Therefore, when the number of tool blades 42a of the processing tool 42 is an odd number, the top shape of the tool becomes the blade groove 42c, so the blade groove 42c is arranged at a predetermined rotational position. In this case, if the number of tool blades 42a of the processing tool 42 is an even number, the top shape of the tool is a blade edge 42b, so that the blade edge 42b is arranged at a predetermined rotational position.

Here, the case where external teeth are formed on a workpiece will also be explained using FIG. 4. When creating external teeth on a workpiece, the tool top shape is placed at a predetermined rotational position as in the case of internal teeth described above. Specifically, the case where the "machining point position" is "upper", that is, the tooth groove is formed at the top position in the Y-axis direction of an annular workpiece, will be explained. In this case, in order to form a tooth groove at the top position, the cutting edge of the tool blade of the processing tool needs to come into contact with the workpiece.

Therefore, when forming a tooth groove at the top position, regardless of whether the number of external teeth on the workpiece is an even or odd number, if the number of tool blades on the machining tool is an odd number, the tooth groove will be in the top shape. It is placed at a predetermined rotational position. Further, when the number of tool blades of the processing tool is an even number, the blade edges are arranged in a top shape at a predetermined rotational position.

Next, as shown in Fig. 4, when a tooth groove is formed at the top position of the workpiece, the "machining point position" is "lower", that is, when machining the lowest part of the workpiece in the Y-axis direction. explain. In this case, the top shape of the tool blade of the processing tool changes depending on whether the number of external teeth on the workpiece is even or odd.

Specifically, when the number of external teeth of the workpiece is an odd number and a tooth groove is formed at the top position, the external teeth are present at the bottom of the workpiece. In this case, the cutting groove of the tool blade of the processing tool needs to come into contact with the lowest part of the workpiece. Therefore, regardless of whether the number of tool blades of the processing tool is an odd number or an even number, the top shape of the tool becomes a blade groove, so the blade groove is arranged at a predetermined rotational position.

Further, when the number of external teeth of the workpiece is an even number, and a tooth groove is formed at the top position, a tooth groove exists at the bottom of the workpiece. In this case, the cutting edge of the tool blade of the processing tool needs to come into contact with the lowest part of the workpiece. Therefore, regardless of whether the number of tool blades of the processing tool is an odd number or an even number, the top shape of the tool becomes a cutting edge, so the cutting edge is arranged at a predetermined rotational position.

At the approach position U1, the machining tool 42 is rotationally controlled, and the cutting edge 42b or the cutting groove 42c is arranged at a predetermined rotational position according to the machining conditions of the sleeve 115 and the tool specifications of the machining tool 42. The approach position U1 is located on the processing tool 42 side from the cutting start position U2, and the approach distance M1 from one end surface of the sleeve 115 is, for example, about 5 mm away. The machining tool 42 is rotationally synchronized with the sleeve 115 from this approach position U1, and the machining tool 42 is relatively fed toward the sleeve 115 from the cutting start position U2, thereby changing the top position of the sleeve 115 and the machining point. A tooth groove 115g is formed at the position.

Then, when the tooth grooves 115g are formed in the sleeve 115, that is, the internal teeth 115a are formed by two tooth grooves 115g, one of the formed tooth grooves 115g is A reference rotation angle P is determined based on the angular position in the reference state. For example, as shown in FIG. 6A, a reference rotation angle P passing through the center of the width of the tooth space 115g is determined.

(4. Regarding cutting start position U2 (correction angle σ) and correction amount σd)
In the gear processing device 1, a reference rotation angle P is determined as shown in FIG. 6A. This reference rotation angle P can be used as a reference during machining, for example, in tooth-missing machining in which internal teeth 115a created in the sleeve 115 are shaved off. That is, since the position of the created internal tooth 115a can be accurately determined based on the reference rotation angle P, the cutting start position U2, such as machining with missing teeth, which does not have a helix angle with respect to the internal tooth 115a, is used as a reference. It can be determined based on the rotation angle P.

Here, in the chamfer cutting process in which the chamfer tooth surfaces 131 and 132 of the gear dropout prevention part 120 are cut into the internal teeth 115a and the taper cutting process in which the taper tooth surfaces 121 and 122 are cut, the approach distance M1 and the helix angle θ are The cutting start position U2 can be calculated geometrically by following Equation 1 using . However, when the calculation is performed using the reference rotation angle P as a reference, a deviation may occur from the original cutting start position U2.

Therefore, according to the above formula 1, a temporary cutting start position U2d is calculated based on the reference rotation angle P, and an actual cutting start position U2j required when actually cutting a taper etc. is calculated. , correct the reference rotation angle P. Specifically, as shown in FIGS. 6B and 6C, the distance in the rotational direction of the sleeve 115 between the temporary cutting start position U2d shown by the broken line and the actual cutting start position U2j shown by the solid line is calculated by a correction amount σd (angle ). In this example, the reference rotation angle P is corrected by rotating the sleeve 115 by the correction amount σd.

Therefore, in the chamfer machining and taper machining in this example, cutting is performed based on the new corrected reference rotation angle P by rotating the sleeve 115 by the correction amount σd. Note that, instead of rotating the sleeve 115 by the correction amount σd, it is also possible to rotate the machining tool 42 by the correction amount σd, or to rotate both the sleeve 115 and the machining tool 42 so that the total amount of rotation becomes the correction amount σd. You can also do it.

(5. Processing by control device 100)
Next, the processing (gear processing method) by the control device 100 will be explained using FIGS. 7 and 8. Here, the machining tool 42A for machining the tooth groove 115g (or for machining missing teeth by cutting off the internal teeth 115a) is attached to the rotating main shaft 40 of the gear machining device 1, and the sleeve 115 is attached to the rotary main shaft 40 of the gear machining device 1. It is assumed that the workpiece holding device 80 is mounted on the workpiece holding device 80 and rotated by the turntable 70 . It is assumed that the machining tool 42B for machining the tapered tooth surfaces 121, 122 and the machining tool 42C for machining the chamfer tooth surfaces 131, 132 are stored in the tool magazine M of the tool exchange device 90 in advance.

Also, the number of teeth of the internal teeth 115a machined into the sleeve 115 (even number or odd number), the number of teeth of the tool blades 42a of the processing tools 42B and 42C (even number or odd number), and the helix angle θf of each tapered tooth surface 121 and 122. , θr, the torsion angles θL and θR of the chamfer tooth surfaces 131 and 132, the approach distance M1, and the cutting movement distance M2 are stored in advance in the storage unit 104. In addition, in the following description, the markings for each tooth groove 115g, 121g, 122g, 131g, and 132g are omitted, and only the markings for each tooth surface 115b, 115c, 121, 122, 131, and 132 are used.

As shown in FIG. 8, the processing control unit 101 of the control device 100 sets the intersection angle φ in skiving processing to a set value, and arranges the processing tool 42A at the approach position U1. Then, as shown in FIG. 10, the machining control unit 101 causes the machining tool 42A to rotate in synchronization with the sleeve 115 while feeding the machining tool 42A in the direction of the rotation axis Lw of the sleeve 115 once or multiple times. Initial processing is performed (S1: first step).

Here, regarding the synchronous rotation of the machining tools 42A (42B, 42C) and the sleeve 115, as shown in FIG. Synchronous rotation is performed so that the ratio is constant. Then, the timing at which the machining tools 42A (42B, 42C) move from the approach position U1 to the cutting start position U2 is such that synchronous rotation is started at time t1, and the machining tools 42A (42B, 42C) and the sleeve 115 each move from the approach position U1 to the cutting start position U2. This may be when the motor is in an accelerated state or when the synchronous rotation is in a stable state at time t2.

Thereby, the processing tool 42A roughly cuts the inner circumference of the sleeve 115 to form the left tooth surface 115b and right tooth surface 115c of the internal tooth 115a, and further forms the left tooth surface 115b and the right tooth surface of the internal tooth 115a. Perform semi-finish cutting on the tooth surface 115c. Semi-finishing cutting is performed by using a tool feed rate lower than the tool feed rate during rough cutting.

When the machining control unit 101 completes cutting of the left tooth flank 115b and right tooth flank 115c of the internal tooth 115a, the processing control unit 101 stores the number (even number or odd number) of the formed internal tooth 115a in the storage unit 104. Thereafter, the machining control unit 101 returns the machining tool 42A to the approach position U1 while maintaining the intersection angle φ.

Subsequently, the processing control unit 101 chamfer-cuts the left chamfer tooth surface 131 and the right chamfer tooth surface 132 (chamfer tooth surface processing step). For this reason, the machining control unit 101 operates the tool exchange device 90 to automatically exchange the machining tool 42A currently mounted on the rotating main shaft 40 with the machining tool 42C stored in the tool magazine M. do. At this time, in the tool changer 90, the detection unit 98 detects the rotational position of the tool blade 42a of the processing tool 42C, specifically, determines whether the cutting edge is located at the uppermost predetermined rotational position in the vertical direction or not. The blade position information indicating whether the blade is located is output to the reference rotation angle determining unit 102.

The reference rotation angle determination unit 102 uses the blade position information acquired from the detection unit 98 of the tool changer 90, the number of blades (even number or odd number) of the processing tool 42C stored in the storage unit 104, and the information stored as described above. The number of teeth (even number or odd number) of the internal teeth 115a is obtained. Based on the relationship shown in the table shown in FIG. 4, the reference rotation angle determining unit 102 determines, as shown in FIG. The tool top shape to be positioned at the top of the tool is determined (S2: second step).

Then, by time t1 shown in FIG. 9, that is, when the machining tool 42C is placed at the approach position U1, the machining control unit 101 causes the machining tool 42C to rotate with the machining tool 42C attached to the rotating main shaft 40. The main shaft 40 is rotated to position the cutting edge at the uppermost position. Further, the reference rotation angle determining unit 102 determines the internal tooth 115a of the turntable 70 in the reference state, as shown in FIG. The angular position is determined by calculating the reference rotation angle P (S2: second step). In this case, the reference rotation angle determination unit 102 takes into consideration the feed rate and the rotation speed of each of the sleeve 115 and the processing tool 42 in addition to the approach position U1 (approach distance M1) and the predetermined rotation position, and determines the reference rotation angle. P can be calculated.

The machining position calculation unit 103 calculates a correction angle σL for determining the cutting start position U2 of the left chamfer tooth surface 131 according to the reference rotation angle P determined as described above and Equation 1 above. Then, as shown in FIG. 10, the machining control unit 101 causes the machining tool 42C and the sleeve 115 to rotate synchronously based on the correction angle σL (S3: third step). At this time, in this example, the machining position calculation unit 103 calculates the correction amount σd, and the machining control unit 101 moves the sleeve 115 by the correction amount σd with the machining tool 42C disposed at the approach position U1. Rotate only. That is, as shown in FIG. 10, the processing control unit 101 corrects the reference rotation angle P by the correction amount σd (S3: third step).

Then, the machining control unit 101 causes the machining tool 42C and the sleeve 115 to rotate synchronously so that the sleeve 115 maintains the correction angle σL. Then, the machining control unit 101 moves the machining tool 42C from the approach position U1 to the sleeve 115 until the machining tool 42C and the sleeve 115 each rotate synchronously at a preset rotation speed at time t2 shown in FIG. It is moved to the cutting start position U2 in the direction of the rotation axis Lw.

Thereafter, the machining control unit 101 feeds the machining tool 42C once or multiple times. Thereby, the processing tool 42C cuts the internal tooth 115a to form the left chamfer tooth surface 131 on the left tooth surface 115b of the internal tooth 115a (S4: fourth step). Then, when the machining of the left chamfer tooth surface 131 is completed, the machining control unit 101 places the machining tool 42C at the approach position U1 while maintaining the intersection angle φ.

Subsequently, the machining control unit 101 adjusts the machining tool 42C as shown in FIG. and the sleeve 115 are rotated synchronously (S3: third step). At this time, in this example, the processing control unit 101 corrects the reference rotation angle P by rotating the sleeve 115 by the correction amount σd calculated by the processing position calculation unit 103, and the sleeve 115 maintains the correction angle σR. The machining tool 42C and the sleeve 115 are rotated synchronously. Then, the machining control unit 101 moves the machining tool 42C from the approach position U1 to the sleeve 115 until the machining tool 42C and the sleeve 115 each rotate synchronously at a preset rotation speed at time t2 shown in FIG. It is moved to the cutting start position U2 in the direction of the rotation axis Lw.

Thereafter, the machining control unit 101 feeds the machining tool 42C once or multiple times. Thereby, the machining tool 42C cuts the internal tooth 115a to form the right chamfer tooth surface 132 on the right tooth surface 115c of the internal tooth 115a (S4: fourth step). When the machining of the right chamfer tooth surface 132 is completed, the machining control unit 101 places the machining tool 42C at the approach position U1 while maintaining the intersection angle φ.

Subsequently, the processing control unit 101 performs taper cutting on the left tapered tooth surface 121 and the right tapered tooth surface 122 (taper tooth surface processing step). Therefore, the machining control unit 101 operates the tool exchange device 90 to automatically exchange the machining tool 42C currently mounted on the rotating main shaft 40 with the machining tool 42B stored in the tool magazine M. do. At this time, in the tool changer 90, the detection unit 98 detects the rotational position of the tool blade 42a of the processing tool 42B, specifically, determines whether the cutting edge is located at the uppermost predetermined rotational position in the vertical direction or not. The blade position information indicating whether the blade is located is output to the reference rotation angle determining unit 102.

The reference rotation angle determination unit 102 uses the blade position information acquired from the detection unit 98 of the tool changer 90, the number of blades (even number or odd number) of the processing tool 42B stored in the storage unit 104, and the number of teeth of the internal teeth 115a. Get (even or odd). Based on the relationship shown in the table shown in FIG. 4, the reference rotation angle determining unit 102 determines, as shown in FIG. The tool top shape is determined (S2: second step).

Then, by time t1 shown in FIG. 9, that is, when the machining tool 42B is placed at the approach position U1, the machining control unit 101 causes the machining tool 42B to rotate with the machining tool 42B attached to the rotating main shaft 40. The main shaft 40 is rotated to position the cutting edge at the uppermost position, that is, at a predetermined rotational position. In this way, by aligning the blade groove of the internal teeth 115a with the cutting edge of the machining tool 42B, the machining control unit 101 can make the machining tool 42B and the sleeve 115 coincide with the reference rotation angle P during synchronous rotation. can.

The machining position calculation unit 103 calculates the value based on the reference rotation angle P determined as described above and the correction angle σf for determining the cutting start position U2 of the left tapered tooth flank 121, which the machining position calculation unit 103 calculated according to the formula 1. , as shown in FIG. 10, the processing tool 42B and the sleeve 115 are rotated synchronously (S3: third step). At this time, in this example, the processing control unit 101 corrects the reference rotation angle P by rotating the sleeve 115 by the correction amount σd calculated by the processing position calculation unit 103, and the sleeve 115 maintains the correction angle σf. The machining tool 42B and the sleeve 115 are rotated synchronously. Then, the machining control unit 101 moves the machining tool 42B from the approach position U1 to the sleeve 115 until the machining tool 42B and the sleeve 115 each rotate synchronously at a preset rotation speed at time t2 shown in FIG. It is moved to the cutting start position U2 in the direction of the rotation axis Lw.

Thereafter, the machining control unit 101 feeds the machining tool 42B once or multiple times. Thereby, the processing tool 42B cuts the internal tooth 115a to form the left tapered tooth surface 121 including the left sub-tooth surface 121a (S4: fourth step). Here, in forming the left tapered tooth surface 121, the processing tool 42B needs to perform a feeding operation and a returning operation in the opposite direction to the feeding operation. In this case, the machining control unit 101 ends the feeding operation at a position shorter than the tooth trace length of the left tapered tooth flank 121 that forms the left tapered tooth flank 121 including the left sub-tooth flank 121a, and returns the machining tool 42B. Move to action. When the cutting of the left tapered tooth surface 121 is completed, the machining control unit 101 places the machining tool 42B at the approach position U1 while maintaining the intersection angle φ.

Subsequently, the machining control unit 101 adjusts the machining tool 42B as shown in FIG. and the sleeve 115 are rotated synchronously (S3: third step). At this time, in this example, the processing control unit 101 corrects the reference rotation angle P by rotating the sleeve 115 by the correction amount σd calculated by the processing position calculation unit 103, and the sleeve 115 maintains the correction angle σr. The machining tool 42B and the sleeve 115 are rotated synchronously (third step). Then, the machining control unit 101 moves the machining tool 42B from the approach position U1 to the sleeve 115 until the machining tool 42B and the sleeve 115 each rotate synchronously at a preset rotation speed at time t2 shown in FIG. It is moved to the cutting start position U2 in the direction of the rotation axis Lw.

Thereafter, the machining control unit 101 feeds the machining tool 42B once or multiple times. Thereby, the processing tool 42B cuts the internal tooth 115a to form the right tapered tooth surface 122 including the right sub-tooth surface 122a (S4: fourth step). When the machining of the right tapered tooth surface 122 is completed, the machining control unit 101 places the machining tool 42C at the approach position U1 while maintaining the intersection angle φ.

Subsequently, the machining control unit 101 performs finish cutting on the left tooth surface 115b and the right tooth surface 115c of the internal tooth 115a. Therefore, the machining control unit 101 operates the tool exchange device 90 to automatically exchange the machining tool 42B currently mounted on the rotating main shaft 40 with the machining tool 42A stored in the tool magazine M. do. Then, the machining control unit 101 feeds the machining tool 42A once in the direction of the rotation axis Lw of the sleeve 115 while rotating the machining tool 42A and the sleeve 115 synchronously with respect to the reference rotation angle P. Thereby, the machining tool 42A performs finish cutting on the left tooth surface 115b and the right tooth surface 115c of the internal tooth 115a (S5: fifth step), as shown in FIG. Note that the finishing cutting process is performed by setting the tool feed rate to be lower than the tool feed rate during the semi-finishing cutting process. In addition, in this cutting process, if necessary, a tooth-missing process is performed in which the internal teeth 115a are shaved off.

Then, the processing control unit 101 ends all processing when the finish cutting of the left tooth surface 115b and the right tooth surface 115c of the internal tooth 115a is completed. Here, by this finishing cutting process, it is possible to remove burrs generated on the left tooth surface 115b and right tooth surface 115c of the internal tooth 115a, and burrs generated on the left taper tooth surface 121 and right taper tooth surface 122. can. Although burrs are generated even after finishing cutting, they are very small and can be removed by post-processing (for example, brushing).

As can be understood from the above explanation, according to the gear processing apparatus 1, even when using a plurality of processing tools 42A, 42B, and 42C, it is necessary to measure the tooth phase of the sleeve 115 to be cut each time. Therefore, the reference rotation angle P can be quickly determined and the next processing can be performed. Therefore, a measuring device for measuring the phase is not required, and the cycle time required for processing can be shortened.

In particular, in skiving machining (gear), the tool blade 42a of the machining tool 42 contacts the sleeve 115 (workpiece) while rotating at a higher speed than in hobbing, and in the order of the rotational direction. At the same time, it is relatively fed in the direction of the rotation axis and processed. Therefore, the processing efficiency is particularly good in skiving processing (gears).

Further, according to the gear processing device 1, there is no need to measure the tooth surfaces 115b, 115c and tooth grooves 115g of the internal teeth 115a of the sleeve 115 (workpiece) using a touch sensor or the like to grasp the tooth phase of the sleeve 115. . In the gear processing device 1, by grasping the state of the tool blade 42a of the processing tool 42 (odd numbered blade, even numbered blade, cutting edge 42b, blade groove 42c), the left and right tooth surfaces 115b, 115c of the internal tooth 115a are , left and right tapered tooth surfaces 121, 122, and left and right chamfered tooth surfaces 131, 132 can be processed with high efficiency and precision.

Furthermore, according to the gear machining apparatus 1, the machining efficiency is further improved by using the most suitable machining tool 42 according to the machining process. In the gear machining apparatus 1, different machining or multiple machining can be performed by exchanging tools, so that multiple machining can be performed with one machine. Therefore, multiple machines are not required, and processing can be performed at low cost and with high efficiency.

(6. Others)
In skiving processing using the gear processing device 1 described above, the intersection between the tool end face of the processing tool 42 and the rotational axis L is positioned on the rotational axis Lw of the sleeve 115 (offset amount "0"), or the intersection can be offset by a predetermined distance in the direction of the rotation axis L of the processing tool 42. In this case as well, it is possible to determine the reference rotation angle P at the approach position U1 and to calculate the correction amount σd, similarly to the present example described above. Therefore, the same effects as in this example described above can be expected.

Further, in the present example described above, as shown in Equation 1 above, the cutting start position U2, that is, the correction angle σ, is calculated using the module m and the number of teeth Z of the sleeve 115. Alternatively, it is possible to calculate the correction angle σ using the module and number of teeth of the processing tool 42 as the module and number of teeth in Equation 1 above.

Specifically, when calculating the module in Equation 1 above, the pitch circle diameter of the workpiece can be used as the pitch circle diameter, and the pitch circle diameter of the processing tool can be used as the pitch circle diameter. . In this case as well, the same effects as in this example described above can be obtained.

DESCRIPTION OF SYMBOLS 1... Gear processing device, 10... Bed, 20... Column, 30... Saddle, 40... Rotating spindle, 41... Spindle motor, 42 (42A, 42B, 42C)... Machining tool, 42a... Tool blade, 42b... Cutting edge, 42c...blade groove, 43...tool holder, 50...table, 60...tilt table, 70...turntable (workpiece rotation drive device), 71...encoder, 80...workpiece holding device, 90...tool changing device, 98... Detection section, 100... Control device, 101... Machining control section, 102... Reference rotation angle determining section, 103... Machining position calculation section, 104... Storage section, 110... Synchromesh mechanism, 115... Sleeve (workpiece), 115a... Internal tooth, 115g...Tooth groove, 120...Gear dropout prevention part, 121, 122...Tapered tooth surface, 131, 132...Chamfer tooth surface, L...Rotation axis, Lw...Rotation axis, M...Tool magazine, M1...Approach distance , M2...cutting movement distance, P...standard rotation angle, U1...approach position, U2...cutting start position, U2j...actual cutting start position, σ...correction angle (cutting start position), σd...correction amount

Claims (7)

A gear processing device that generates a plurality of teeth by cutting a peripheral surface of the workpiece by rotating a processing tool synchronously with the workpiece and relatively feeding the workpiece in the direction of the rotational axis of the workpiece, the gear processing device comprising:
a workpiece rotation drive device that rotationally drives the workpiece with a reference state in which the detected value of the rotation angle is a predetermined value;
A control device that controls the relative position of the processing tool and the workpiece ,
The control device includes:
As a machining preparation step, the machining tool is located at an approach position spaced apart from the workpiece in the direction of the rotation axis,
As the machining preparation step, at the approach position , the rotational position of the tool blade of the machining tool is positioned at a predetermined tool blade position according to the position of the tooth groove already formed on the circumferential surface of the workpiece. let me ,
As the machining preparation step, the already formed tooth groove is moved to a predetermined tooth groove position based on the approach position of the machining tool and the predetermined tool blade position of the tool blade of the machining tool at the approach position. Determine a reference rotation angle that is the rotation angle of the workpiece rotation drive device when the workpiece rotation drive device is located at
As the machining preparation step, in order to position the already formed tooth groove at the predetermined tooth groove position, the rotation angle of the workpiece rotation drive device is positioned at the reference rotation angle,
As a machining step following the machining preparation step, the machining tool is relatively sent from the approach position in the direction of the rotation axis of the workpiece, and the machining tool is rotated in synchronization with the workpiece. , a gear processing device that performs a cutting process on the teeth that form the tooth grooves of the workpiece that have already been formed . The control device includes:
As the machining preparation step, a tooth surface having a helix angle with respect to the tooth forming the tooth groove of the workpiece that has already been formed is cut , and the rotation angle of the workpiece rotation drive device is When the machining process is started with the machining tool positioned at the reference rotation angle , the machining tool located at the approach position moves in the direction of the rotation axis until it comes into contact with the workpiece, and the approach distance and the torsion angle. Based on this, calculate a cutting start position that is a circumferential position of the workpiece when the processing tool starts cutting the tooth surface ,
As the machining preparation step, the machining start position calculated when the machining process is started with the rotation angle of the workpiece rotation drive device positioned at the reference rotation angle, and the machining start position calculated when machining the tooth surface. Calculate a correction amount corresponding to the difference in the rotation direction of the workpiece from the actual cutting start position , which is the target position ,
The gear machining device according to claim 1, wherein, as the machining preparation step , at least one of the rotation angle of the workpiece rotation drive device and the machining tool is rotated using the correction amount of the reference rotation angle. The gear processing apparatus according to claim 2 , wherein the cutting process is a taper cutting process in which a tapered tooth surface is cut into the tooth, or a chamfer cutting process in which a chamfer tooth surface is cut into the tooth. The control device includes:
Further comprising a storage unit that stores machining conditions for creating the teeth by cutting the tooth grooves on the workpiece and tool specifications of the machining tool,
The gear processing device according to any one of claims 1 to 3 , wherein the predetermined tool blade position is determined based on the processing conditions and the tool specifications. The machining conditions are a case where an even number or odd number of internal teeth are created on the workpiece, the tool specifications are a case where the tool blade of the machining tool is an even number or an odd number, and When machining the tooth groove in a first direction perpendicular to the axial direction,
The gear processing apparatus according to claim 4 , wherein the control device rotationally controls the processing tool to bring the cutting edge of the tool blade to the predetermined tool blade position. A gear that cuts the circumferential surface of the workpiece by rotating a processing tool synchronously with the workpiece and relatively feeding it in the direction of the rotational axis of the workpiece, thereby creating a plurality of teeth on the circumferential surface. A processing method,
a workpiece rotation drive device that rotationally drives the workpiece with a reference state in which the detected value of the rotation angle is a predetermined value;
using a control device that controls the relative position of the processing tool and the workpiece,
By the control device,
As a machining preparation step, the machining tool is located at an approach position spaced apart from the workpiece in the direction of the rotation axis,
As the machining preparation step, at the approach position , the rotational position of the tool blade of the machining tool is positioned at a predetermined tool blade position according to the position of the tooth groove already formed on the circumferential surface of the workpiece. let me ,
As the machining preparation step, the already formed tooth groove is moved to a predetermined tooth groove position based on the approach position of the machining tool and the predetermined tool blade position of the tool blade of the machining tool at the approach position. Determine a reference rotation angle that is the rotation angle of the workpiece rotation drive device when the workpiece rotation drive device is located at
As the machining preparation step, in order to position the already formed tooth groove at the predetermined tooth groove position, the rotation angle of the workpiece rotation drive device is positioned at the reference rotation angle,
As a machining step following the machining preparation step, the machining tool is relatively sent from the approach position in the direction of the rotation axis of the workpiece, and the machining tool is rotated in synchronization with the workpiece. . A gear machining method, in which the teeth forming the tooth grooves of the workpiece that have already been formed are cut . By the control device,
As the machining preparation step, a tooth surface having a helix angle with respect to the tooth forming the tooth groove of the workpiece that has already been formed is cut , and the rotation angle of the workpiece rotation drive device is When the machining process is started with the machining tool positioned at the reference rotation angle , the machining tool located at the approach position moves in the direction of the rotation axis until it comes into contact with the workpiece, and the approach distance and the torsion angle. Based on this, calculate a cutting start position that is a circumferential position of the workpiece when the processing tool starts cutting the tooth surface ,
As the machining preparation step, the machining start position calculated when the machining process is started with the rotation angle of the workpiece rotation drive device positioned at the reference rotation angle, and the machining start position calculated when machining the tooth surface. Calculate a correction amount corresponding to the difference in the rotation direction of the workpiece from the actual cutting start position, which is the target position,
The gear machining method according to claim 6 , wherein in the machining preparation step, at least one of the rotation angle of the workpiece rotation drive device and the machining tool is rotated using the correction amount of the reference rotation angle .

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