Manufacturing method of gearwheel

Abstract

To provide a manufacturing method of a gearwheel which can improve production efficiency of a composite processing machine that performs gear cut-processing of a workpiece and chamfer processing.SOLUTION: A manufacturing method of a gearwheel comprises the steps of: adjusting a phase between a tooth of a gearwheel to be cut and a chamfering cutter to be a prescribed phase at an initial processing of a workpiece and installing, when processing the workpiece on and after a second time, a gear cutting holder to a tool spindle at the same phase as the initial processing of the workpiece to perform a gear cutting processing (step S10, step S11); installing a chamfering cutter holder instead to the tool spindle at the same phase as the initial processing of the workpiece (step S12); adjusting a rotational phase between a workpiece spindle and the tool spindle on the basis of the rotational phase between the workpiece spindle and the tool spindle in which at least one of the workpiece spindle and the tool spindle is rotated to store the rotational phase through a phase storage step (step S13); and starting chamfering processing at the rotational phase adjusted by a spindle phase adjusting process (step S14).SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a gear by performing tooth cutting and chamfering on a workpiece using a composite machining machine.

Background Art

[0002] Patent Document 1 describes a gear processing apparatus configured to attach a to-be-cut gear that has been tooth-cut to a workpiece support portion and chamfer both end corners in the tooth width direction of the to-be-cut gear by pressing them with a flanging cutter. Note that this gear processing apparatus defines the axial intersection angle between the workpiece support portion and the cutter support portion that supports the flanging cutter, the tooth tip radius of the flanging cutter, etc., in order to suppress the swelling of the tooth surface by chamfering the corners of the to-be-cut gear with the flanging cutter.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When chamfering the corners of a to-be-cut gear with a flanging cutter as in the gear processing apparatus described in Patent Document 1, chamfering is performed with the phases of the teeth of the flanging cutter and the teeth of the to-be-cut gear being aligned. Therefore, when tooth cutting is performed on a workpiece to form a to-be-cut gear, and then the to-be-cut gear is attached to a gear processing apparatus for chamfering the to-be-cut gear and chamfering is performed, the phase between the to-be-cut gear and the flanging cutter needs to be aligned each time chamfering is performed, which may reduce the productivity when manufacturing a plurality of gears.

[0005] In addition, when a contact type phase determination pin using a probe or the like for determining the phase of the gear to be cut is provided on the member that supports the chamfering cutter, the operating resistance of the phase determination pin gradually increases due to machining powder generated by chamfering or the like, or machining powder may get caught between the first-stage pin and the teeth of the gear to be cut. In such a case, the phases of the teeth of the gear to be cut and the teeth of the chamfering cutter cannot be accurately aligned, and there is a possibility that productivity may decrease, such as by stopping the equipment for maintenance.

[0006] The present invention has been made by paying attention to the above technical problems, and an object thereof is to provide a method for manufacturing a gear that can improve the production efficiency of a composite processing machine that performs tooth cutting and chamfering of a workpiece.

Means for Solving the Problems

[0007] In order to achieve the above object, the present invention attaches a tooth cutting cutter holder having a tooth cutting cutter to a tool spindle, performs tooth cutting on a workpiece attached to a workpiece spindle, replaces the chamfering cutter holder having a chamfering cutter with the tool spindle, and meshes the chamfering cutter with the teeth of a gear to be cut, which is the workpiece after the tooth cutting, to perform chamfering of the gear to be cut. A method for manufacturing a gear by a composite machining machine, wherein during the machining of the first workpiece, a first tooth cutting step of performing the tooth cutting, a first tool replacement step of replacing the tool spindle with the chamfering cutter holder, and a phase adjustment step of adjusting the phase between the teeth of the gear to be cut and the chamfering cutter to a predetermined phase, and a phase storage step of storing the rotational phase between the workpiece spindle and the tool spindle when adjusted in the phase adjustment step, and a first chamfering step of starting the chamfering at the predetermined phase adjusted by the phase adjustment step, machining the workpiece in this order, and during the machining of the workpiece for the second and subsequent times, a second tooth cutting step of attaching the tooth cutting cutter holder to the tool spindle in the same phase as during the machining of the first workpiece and performing the tooth cutting, and a second tool replacement step of replacing the chamfering cutter holder with the tool spindle in the same phase as during the machining of the first workpiece, and rotating at least one of the workpiece spindle and the tool spindle to adjust the rotational phase between the workpiece spindle and the tool spindle based on the rotational phase between the workpiece spindle and the tool spindle stored in the phase storage step, and a second chamfering step of starting the chamfering at the rotational phase adjusted by the axial phase adjustment step, machining the workpiece in this order.

[0008] In the present invention, in the second tooth cutting step, when performing a hob shift that changes the contact position between the tooth cutting cutter and the workpiece from the first tooth cutting step, in the axial phase adjustment step, the change in phase between the chamfering cutter and the workpiece due to the hob shift may be corrected to adjust the rotational phase between the workpiece spindle and the tool spindle.

[0009] In the present invention, when machining the workpiece immediately after replacing the tooth cutting cutter attached to the tooth cutting cutter holder, instead of the axial phase adjustment step, the phase between the tooth of the gear to be cut and the chamfering cutter is readjusted to a predetermined phase, and the rotational phase between the workpiece spindle and the tool spindle stored in the phase storage step may be updated to the rotational phase between the workpiece spindle and the tool spindle at the time of the readjustment.

[0010] In the present invention, the chamfering cutter holder includes a phase determining device that is pressed to one side by an elastic force and is reciprocally movable in the pressing direction. The phase adjustment step holds the chamfering cutter holder at a predetermined position, and with the workpiece spindle rotatable, the workpiece spindle is moved so that the tooth of the gear to be cut is pressed by the phase determining device and the workpiece spindle rotates, thereby adjusting the phase between the tooth of the gear to be cut and the chamfering cutter to a predetermined phase.

[0011] In the present invention, the tooth cutting cutter holder and the tool spindle may be configured to be always assembled in the same phase, and the chamfering cutter holder and the tool spindle may be configured to be always assembled in the same phase.

Effects of the Invention

[0012] According to the present invention, a gear cutting cutter holder or a chamfering cutter holder is assembled to a tool spindle in the same phase when machining the first workpiece and when machining the workpieces after the second time. Also, when machining the first workpiece, the phase of the chamfering cutter and the gear to be cut is adjusted, and the rotational phase between the tool spindle and the workpiece spindle at that time is memorized. Then, when machining the workpieces after the second time, the rotational phase between the tool spindle and the workpiece spindle is adjusted to the memorized rotational phase. Therefore, the phase of the teeth of the gear to be cut by gear cutting with respect to the workpiece spindle is always the same phase, and since the rotational phase of the tool spindle with respect to the workpiece spindle is the same phase, the phase of the gear to be cut and the phase of the chamfering cutter can be set to be the same as when machining the first workpiece. That is, when machining the workpieces after the second time, it is not necessary to adjust the phase between the gear to be cut and the chamfering cutter, or the frequency thereof can be reduced, and productivity can be improved.

Brief Description of the Drawings

[0013]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Embodiments for Carrying Out the Invention

[0014] Next, embodiments of the present invention will be described with reference to the accompanying drawings. Note that the embodiments described below are merely examples when implementing the present invention and do not limit the present invention.

[0015] An example of a composite processing machine according to an embodiment of the present invention is shown in FIG. 1. The composite processing machine 1 shown in FIG. 1 includes a fixed bed 2, a work holding device 3 provided so as to be movable in the depth direction of the fixed bed 2 (the X direction in FIG. 1), and a tool holding device 4 provided so as to be movable in a direction approaching and separating from the work holding device 3 (the Z direction in FIG. 1). Specifically, two guide rib portions 5 parallel to the X direction are provided on the fixed bed 2, and the work holding device 3 is configured to move while being guided by the guide rib portions 5. Similarly, two guide rib portions 6 parallel to the Z direction are provided on the fixed bed 2, and the tool holding device 4 is configured to move while being guided by the guide rib portions 6.

[0016] The work holding device 3 is composed of a pedestal portion 7 placed on the guide rib portion 5, a columnar rotating portion 8 placed on the upper surface of the pedestal portion 7, a driving portion 9 fixed to the upper surface of the rotating portion 8, and a work spindle 10 for attaching a work.

[0017] The pedestal portion 7 is for moving the work in the X direction in FIG. 1, and a driving device having a motor (not shown) for driving on the guide rib portion 5 is built therein. Further, a position sensor (not shown) for detecting the position of the pedestal portion 7 (coordinates on the fixed bed 2) is provided on the pedestal portion 7 or the fixed bed 2.

[0018] The rotating portion 8 is for changing the direction of the work spindle 10 described later, and an actuator such as a motor (not shown) for rotating about the central axis of the rotating portion 8 is built therein.

[0019] The drive unit 9 is provided with a workpiece spindle 10 extending toward the tool holding device 4 side. An actuator such as a motor (not shown) for rotating the workpiece spindle 10 is incorporated therein, and a brake is provided to generate a reaction force during workpiece machining, in other words, to suppress the rotation of the workpiece spindle 10. Further, a workpiece rotation angle sensor for detecting the rotation angle (rotation phase) of the workpiece spindle 10 is provided. In the example shown in FIG. 1, the drive unit 9 is fixed at a position offset from the rotation center axis in the rotating unit 8, more specifically, at a position on the opposite side of the tool holding device 4 across the rotation center axis line.

[0020] The workpiece spindle 10 is provided with a chuck (not shown) for fixing the workpiece. This chuck only needs to be able to fix the workpiece and can be configured in the same way as the chuck for fixing a machining object on a conventional lathe or the like.

[0021] The tool holding device 4 is composed of a base portion 11 placed on the guide rib portion 6, a lifting portion 12 movably provided in the vertical direction (Y direction in FIG. 1) on the surface of the base portion 11 facing the workpiece holding device 3 side, a drive portion 13 fixed to the surface of the lifting portion 12 facing the workpiece holding device 3 side, and a tool spindle 14 protruding from the drive portion 13 toward the workpiece holding device 3 side.

[0022] The base portion 11 is for approaching and separating the tool from the workpiece, and a drive device having a motor (not shown) for driving on the guide rib portion 6 is incorporated therein. Further, a position sensor (not shown) for detecting the position of the base portion 11 (coordinates on the fixed bed 2) is provided on the base portion 11 or the fixed bed 2.

[0023] On the surface of the base portion 11 facing the work holding device 3 side, two guide rib portions 15 parallel to the height direction of the base portion 11 (Y direction in FIG. 1) are provided, and the elevating portion 12 is configured to move along the guide rib portions 15. Therefore, a driving device having a motor (not shown) for driving along the guide rib portions 15 is built in the elevating portion 12. Further, a position sensor (not shown) for detecting the position (height) of the elevating portion 12 is provided on the elevating portion 12 or the base portion 11.

[0024] The drive unit 13 is provided with a tool spindle 14 extending toward the work holding device 3 side, and an actuator such as a motor (not shown) for rotating the tool spindle 14 is built in, and a tool rotation angle sensor for detecting the rotation angle (rotation phase) of the tool spindle 14 is provided.

[0025] The tool spindle 14 is provided with protrusions (not shown) that fit into the U-grooves 16a and 17a formed in the hob cutter holder 16 and the facing cutter holder 17 described later, and the U-grooves 16a and 17a of the hob cutter holder 16 and the facing cutter holder 17 are configured to be fitted and fixed to the protrusions. That is, the hob cutter holder 16 and the facing cutter holder 17 are configured to be fixed to the tool spindle 14 so that the rotation angles (rotation phases) of the hob cutter holder 16 and the facing cutter holder 17 are always the same as the rotation angle (rotation phase) of the tool spindle 14.

[0026] Figure 2 shows an example of a hob cutter holder 16 attached to the tool spindle 14. The hob cutter holder 16 shown in Figure 2 is a shaft-shaped member in which a U-groove 16a that fits into a protrusion provided on the tool spindle 14 is formed, and a hob cutter 18 is fitted and provided on the tip side thereof. This hob cutter 18 is a tooth cutting tool having cutting edges provided with a plurality of grooves crossing the screw threads of the worm and provided with relief surfaces between adjacent grooves along the screw threads, similar to a conventional hob cutter. This hob cutter 18 corresponds to the "tooth cutting cutter" in the embodiment of the present invention, and the hob cutter holder 16 corresponds to the "tooth cutting cutter holder" in the embodiment of the present invention.

[0027] The hob cutter 18 and the hob cutter holder 16 are engaged by a key. That is, a key groove 18a is formed on the inner peripheral surface of the hob cutter 18, and a key 16b that engages with the key groove 18a is formed on the outer peripheral surface of the hob cutter holder 16. That is, the hob cutter 18 and the hob cutter holder 16 are configured to be assembled so that their rotation angles (rotation phases) are always the same.

[0028] Note that a male screw is formed at the tip of the hob cutter holder 16, and after the hob cutter 18 is fitted, a nut 19 is assembled to the male screw so that the hob cutter 18 is fixed to the hob cutter holder 16.

[0029] FIG. 3 shows an example of a chamfering cutter holder 17 attached to the tool spindle 14. The chamfering cutter holder 17 shown in FIG. 3 is a shaft-shaped member in which a U-groove 17a that fits into a protrusion provided on the tool spindle 14 is formed, and a chamfering cutter 20 is fitted and provided on the tip side thereof. This chamfering cutter 20 is a tool that chamfers the corner portions at both ends in the tooth width direction of a gear, and includes two chamfering gears 21 spaced apart by the same distance as the tooth width of the gear to be chamfered. The pitch of the chamfering gear 21 is formed to be the same as the pitch of the gear to be chamfered (i.e., the workpiece W). With the tooth phases of the chamfering cutter 20 (i.e., the chamfering gear 21) and the workpiece W aligned, the chamfering cutter 20 (i.e., the chamfering gear 21) and the workpiece W are rotated to perform chamfering. This chamfering cutter 20 corresponds to the "chamfering cutter" in the embodiment of the present invention, and the chamfering cutter holder 17 corresponds to the "chamfering cutter holder" in the embodiment of the present invention.

[0030] The chamfering cutter 20 and the chamfering cutter holder 17 are engaged by a key or the like so that their rotation angles (rotation phases) are always the same.

[0031] Note that a male thread is formed at the tip of the chamfering cutter holder 17, and after the chamfering cutter 20 is fitted, the nut 22 is assembled to the male thread to fix the chamfering cutter 20 to the chamfering cutter holder 17.

[0032] Also, on the tip side of the mounting portion of the flaging cutter 20 in the flaging cutter holder 17, a phase determination pin 23 such as a probe protruding toward the work W is provided. This phase determination pin 23 is pressed by an elastic member such as a spring so as to be separated in the radial direction of the flaging cutter holder 17, and is provided so as to be able to reciprocate in the pressing direction. That is, by moving the flaging cutter holder 17 to a predetermined position, the tip of the phase determination pin 23 is provided so as to contact the work W. Therefore, when the tip contacts the tooth surface of the work W, the elastic force of the elastic member pressing the phase determination pin 23 and the load in the direction of rotating the work W corresponding to the inclination angle of the tooth surface act on the work W. This phase determination pin 23 corresponds to the "phase determination device" in the embodiment of the present invention.

[0033] An electronic control device (hereinafter referred to as a controller) 24 for controlling various drive devices provided in the above-described composite processing machine 1 is built in the composite processing machine 1. This controller 24 is configured to input signals from various sensors provided in the composite processing machine 1 and output signals to drive devices and the like provided in the composite processing machine 1 based on the input signals and programs and the like stored in advance.

[0034] This composite processing machine 1 is configured to perform gear cutting and chamfering on a work W assembled to a work spindle 10. FIG. 4 shows a flowchart for explaining the procedure for manufacturing the first gear when mass-producing a gear with predetermined specifications, that is, the procedure for performing gear cutting and chamfering on the first work W. In the example shown in FIG. 4, after assembling the work W to the work spindle 10, first, the hob cutter holder 16 with the hob cutter 18 assembled is attached to the tool spindle 14 (step S1).

[0035] Then, starting from the state where the rotation angle of the work spindle 10 is set as a predetermined initial work rotation angle and the rotation angle of the tool spindle 14 is set as a predetermined initial tool rotation angle, gear cutting is performed on the work W (step S2). Specifically, the pedestal portion 7, the rotating portion 8, the base portion 11, and the elevating portion 12 are controlled to align the positions of the hob cutter 18 and the work W. In this state, while rotating the work spindle 10 and the tool spindle 14, the pedestal portion 7 is moved to perform gear cutting on the work W. This step of performing gear cutting can be carried out in the same manner as the conventional gear cutting of gears. Note that, according to the twist angle of the gear to be manufactured, the relative angle between the work spindle 10 and the tool spindle 14 is adjusted to perform gear cutting. Therefore, the gear manufactured by this gear cutting may be a gear having a twist angle such as a helical gear or a spur gear, or a spur gear. The process of this step S2 corresponds to the "first gear cutting process" in the embodiment of the present invention.

[0036] Subsequently, the hob cutter holder 16 is removed from the tool spindle 14, and the flanging cutter holder 17 with the flanging cutter 20 assembled thereto is replaced (step S3). The process of this step S3 corresponds to the "first tool replacement process" in the embodiment of the present invention.

[0037] Next, the phase between the chamfering cutter 20 and the work W that has been tooth-cut (hereinafter referred to as the gear to be cut) is adjusted (step S4). This phase adjustment first releases the brake for stopping the rotation of the work spindle 10 to make the work spindle 10 rotatable. Next, the rotation angle of the tool spindle 14 is rotated to a predetermined phase determination rotation angle at which the phase determination pin 23 faces the gear to be cut W side, and this rotation angle is maintained. In that state, the tool holding device 4 is moved to a predetermined position. Specifically, in the Y direction in FIG. 1, when the gear to be cut W is arranged at a predetermined position for chamfering, the tool holding device 4 is moved so that the phase determination pin 23 is located at the center in the tooth width direction of the gear to be cut W. Also, in the Z direction in FIG. 1, the distance between the work spindle 10 and the tool spindle 14 is greater than the tooth thickness of the gear to be cut W, and the gear to be cut W is arranged at a predetermined position for chamfering, and when the tooth groove of the gear to be cut W faces the chamfering cutter holder 16 side, the tool holding device 4 is moved to a distance at which the tip of the phase determination pin 23 contacts the tooth groove.

[0038] Also, with the rotation angle of the work W (rotation angle of the drive unit 9) fixed to the rotation angle during chamfering, the work holding device 3 is made to standby at a position offset in the X direction from a predetermined position for chamfering. Then, the work holding device 3 is moved toward a predetermined position for chamfering.

[0039] By moving the work holding device 3 in this way, in the X direction in FIG. 1, the phase determination pin 23 contacts and presses against the tooth surface of the gear to be cut W, causing the work spindle 10 to rotate so that the tooth groove faces the phase determination pin 23 side. Therefore, when the work holding device 3 moves to a predetermined position for chamfering, the tooth groove of the gear to be cut W faces the chamfering cutter holder 16 side, and in that state, the brake for stopping the rotation of the work spindle 10 is applied. The process of this step S4 corresponds to the "phase adjustment process" in the embodiment of the present invention.

[0040] Following this step S4, the rotation angle of the work spindle 10 rotated in step S4 is stored in the controller 24 as the chamfering rotation angle (step S5). The process of this step S5 corresponds to the "phase storage process" in the embodiment of the present invention.

[0041] Then, chamfering is performed (step S6). That is, the positions of the base portion 11 and the elevating portion 12 are adjusted, the flanging cutter 20 is meshed with the gear to be cut W, and at least one of the work spindle 10 and the tool spindle 14 is rotated to chamfer the corner portion of the gear to be cut W. The process of this step S6 corresponds to the "first chamfering process" in the embodiment of the present invention. In this way, through each process, the first work W is subjected to gear cutting and chamfering.

[0042] Fig. 5 shows a flowchart for explaining the procedure of performing gear cutting and chamfering on the work W after the second time. In the example shown in Fig. 5, first, the hob cutter holder 16 is attached to the tool spindle 14 in the same phase as when machining the first work W (step S10). In the example shown here, as shown in Fig. 2, the hob cutter holder 16 is formed with a U-groove 16a that fits into the protrusion provided on the tool spindle 14. Therefore, by directly attaching the hob cutter holder 16 to the tool spindle 14, the hob cutter holder 16 is attached to the tool spindle 14 in the same phase as the hob cutter holder 16 when gear cutting the first work W.

[0043] Then, in the same manner as in step S2, gear cutting is performed on the workpiece W starting from a state where the rotation angle of the workpiece spindle 10 is set as the initial workpiece rotation angle and the rotation angle of the tool spindle 14 is set as the initial tool rotation angle (step S11). As described above, the hob cutter holder 16 during the gear cutting of the first workpiece W and the hob cutter holder 16 during the gear cutting of the workpiece W after the second time are assembled in the same phase with respect to the tool spindle 14. Also, gear cutting is performed starting from a state where the rotation angle of the workpiece spindle 10 is set as the initial workpiece rotation angle and the rotation angle of the tool spindle 14 is set as the initial tool rotation angle. That is, gear cutting is performed under the same conditions as during the gear cutting of the first workpiece W. Therefore, the phase of the teeth of the gear W to be cut with respect to the workpiece spindle 10 after being gear cut in step S11 is the same as the phase of the teeth of the gear W to be cut in step S2. The process of this step S11 corresponds to the "second gear cutting process" in the embodiment of the present invention.

[0044] Subsequently, the hob cutter holder 16 is removed from the tool spindle 14, and the facing cutter holder 17 with the facing cutter 20 assembled thereto is attached to the tool spindle 14 in the same phase as when the first workpiece W was processed (step S12). In the example shown here, as shown in FIG. 3, since the facing cutter holder 17 is formed with a U-groove 17a that fits into the protrusion provided on the tool spindle 14, by attaching the facing cutter holder 17 to the tool spindle 14 as it is, the facing cutter holder 17 is attached to the tool spindle 14 in the same phase as the facing cutter holder 17 when the first workpiece W was gear cut. The process of this step S12 corresponds to the "second tool replacement process" in the embodiment of the present invention.

[0045] As described above, the phase of the teeth of the gear W to be machined after the tooth cutting process in step S11 with respect to the work spindle 10 is the same as the phase of the teeth of the gear W to be machined after the tooth cutting process in step S2 with respect to the work spindle 10. Also, the phase of the facing cutter 20 assembled to the tool spindle 14 in step S12 is the same as the phase of the facing cutter 20 attached to the tool spindle 14 during the machining of the first workpiece W. Therefore, during the machining of the workpiece W for the second and subsequent times, without adjusting the phase between the facing cutter 20 and the gear W to be machined, the rotation angle of the work spindle 10 is controlled to the chamfering rotation angle stored in the controller 24 in step S5 (step S13), and chamfering is performed (step S14). In step S13, the rotation angle of the tool spindle 14 is controlled to the same phase-determining rotation angle as in step S4 above. The process of this step S13 corresponds to the "axis phase adjustment process" in the embodiment of the present invention, and the process of step S14 corresponds to the "second chamfering process" in the embodiment of the present invention.

[0046] As described above, the hob cutter holder 16 and the facing cutter holder 17 are configured to be assembled to the tool spindle 14 in the same phase as during the machining of the first workpiece W. Also, the phase between the facing cutter 20 and the gear W to be machined is adjusted during the machining of the first workpiece W, and the rotation angles of the tool spindle 14 and the work spindle 10 at that time are stored. Then, during the machining of the workpiece W for the second and subsequent times, the rotation angle of the tool spindle 14 is controlled to the phase-determining rotation angle, and the rotation angle of the work spindle 10 is controlled to the stored chamfering rotation angle. Therefore, since the phase of the teeth of the gear W to be machined after tooth cutting with respect to the work spindle 10 is always the same phase, by controlling the rotation angle of the tool spindle 14 to the phase-determining rotation angle, the phase of the gear W to be machined and the phase of the facing cutter 20 can be set to be the same as during the machining of the first workpiece W. That is, during the machining of the workpiece W for the second and subsequent times, there is no need to adjust the phase between the facing cutter 20 and the gear W to be machined by the phase-determining pin 23, and the frequency thereof can be reduced, improving productivity.

[0047] In addition, it is possible to suppress a decrease in the phase adjustment accuracy due to the operating resistance of the phase determination pin 23 for adjusting the phase, and it is also possible to suppress a decrease in productivity caused by stopping the equipment for maintenance in order to suppress such operating resistance. Furthermore, in order to suppress the phase of the work gear W from deviating from the normal position due to the machining powder getting caught between the phase determination pin 23 and the teeth of the work gear W, it is possible to suppress a decrease in productivity caused by stopping the equipment for maintenance.

[0048] On the other hand, the hob cutter 18 has a plurality of teeth formed at a predetermined pitch in the axial direction. In one tooth cutting process, tooth cutting is performed using only the teeth at a predetermined position in the axial direction, and in the next tooth cutting process, tooth cutting is performed using the teeth at other positions in the axial direction. That is, a hob shift is performed to change the contact position between the hob cutter 18 and the work W. In that case, when performing a hob shift, in step S13, it is preferable to correct the rotation angle of the work spindle 10 by the amount of change in the phase between the flanging cutter 20 and the work W due to the hob shift. Specifically, in step S13 or subsequent to step S13, based on the pitch distance between pitches in the axial direction of the hob cutter 18, the hob shift amount (axial movement amount), the radius of the work W, etc., the correction amount of the rotation angle of the work spindle 10 is obtained, and this correction amount is added to the chamfering rotation angle to control the rotation angle of the work spindle 10.

[0049] Even when the hob shift is performed in this way, it is possible to perform chamfering by controlling the rotation angle of the work spindle 10 without going through the process of adjusting the phase between the work gear W and the flanging cutter 20. Therefore, even when the hob shift is performed, productivity can be improved.

[0050] Also, when performing tooth cutting on a plurality of workpieces W, it is necessary to change the hob cutter 18. When the hob cutter 18 is changed in this way, the phase of the hob cutter 18 newly assembled to the hob cutter holder 16 does not necessarily match the phase of the removed hob cutter 18. Therefore, when the hob cutter 18 is replaced, it is preferable to correct (update) the chamfering rotation angle.

[0051] Specifically, perform the same steps as steps S10 to S12 shown in FIG. 4. Instead of step S13, adjust the phase between the facing cutter 20 and the gear to be cut W in the same manner as step S4 above, and correct (update) the rotation angle of the work spindle 10 as the chamfering rotation angle and store it in the controller 24. Then, perform chamfering in the same manner as step S14. For the subsequent machining of the workpiece W, without going through the process of adjusting the phase between the gear to be cut W and the facing cutter 20, control the rotation angle of the work spindle 10 based on the updated chamfering rotation angle to perform chamfering. That is, when the hob cutter 18 is reassembled, only during the machining immediately after that, readjust the phase between the facing cutter 20 and the gear to be cut W.

[0052] By correcting the chamfering rotation angle when the hob cutter 18 is reassembled in this way, during the subsequent machining of the workpiece W, it is possible to control the rotation angle of the work spindle 10 to perform chamfering without going through the process of adjusting the phase between the gear to be cut W and the facing cutter 20, and the productivity can be improved.

[0053] In the above-described example, a contact-type phase-determining pin 23 is used to align the phases of the flanging cutter 20 and the gear W to be cut. However, the phases of the flanging cutter 20 and the gear W to be cut may also be aligned by a non-contact distance sensor using a laser or the like. Specifically, while detecting the rotation angle of the gear W to be cut by the distance sensor, the work spindle 10 is rotated, and based on the distance detected by the distance sensor, the rotation angle of the work spindle 10 is adjusted so that the tooth surface of the gear W to be cut faces the flanging cutter holder 17 side, and the adjusted rotation angle of the work spindle 10 may be stored in the controller 24 as the chamfering rotation angle.

Explanation of Signs

[0054] 1 Machining center 3 Work holding device 4 Tool holding device 7 Pedestal part 8 Rotating part 9 Driving part 10 Work spindle 11 Base part 12 Lifting part 13 Driving part 14 Tool spindle 16 Hob cutter holder 16a, 17a U-groove 17 Flanging cutter holder 18 Hob cutter 20 Flanging cutter 21 Chamfering gear 23 Phase-determining pin 24 Controller W Work (gear to be cut)

Claims

1. A method for manufacturing a gear by a compound machining machine, comprising attaching a tooth cutting cutter holder having a tooth cutting cutter to a tool spindle to perform tooth cutting on a workpiece attached to a workpiece spindle, replacing the tooth cutting cutter holder with a chamfering cutter holder having a chamfering cutter on the tool spindle, and meshing the chamfering cutter with the teeth of a gear to be cut, which is the workpiece after the tooth cutting, to perform chamfering on the gear to be cut, wherein: During the machining of the first workpiece, the method includes a first tooth cutting step of performing the tooth cutting, a first tool replacement step of replacing the tool spindle with the chamfering cutter holder, a phase adjustment step of adjusting the phase between the teeth of the gear to be cut and the chamfering cutter to a predetermined phase, a phase storage step of storing the rotational phase between the workpiece spindle and the tool spindle when adjusted in the phase adjustment step, and a first chamfering step of starting the chamfering at the predetermined phase adjusted in the phase adjustment step, and machining the workpiece in this order. During the machining of the workpiece for the second time and thereafter, the method includes a second tooth cutting step of attaching the tooth cutting cutter holder to the tool spindle in the same phase as during the machining of the first workpiece to perform the tooth cutting, a second tool replacement step of replacing the tool spindle with the chamfering cutter holder in the same phase as during the machining of the first workpiece, an axial phase adjustment step of rotating at least one of the workpiece spindle and the tool spindle and adjusting the rotational phase between the workpiece spindle and the tool spindle based on the rotational phase between the workpiece spindle and the tool spindle stored in the phase storage step, and a second chamfering machining step of starting the chamfering at the rotational phase adjusted in the axial phase adjustment step, and machining the workpiece in this order. A method for manufacturing a gear, characterized by the above.

2. The method for manufacturing a gear according to claim 1, wherein: When performing a hob shift that changes the contact position between the tooth cutting cutter and the workpiece in the second tooth cutting step, in the axial phase adjustment step, the change in the phase between the chamfering cutter and the workpiece due to the hob shift is corrected, and the rotational phase between the workpiece spindle and the tool spindle is adjusted. A method for manufacturing a gear, characterized by the above.

3. The method for manufacturing a gear according to claim 1, wherein: When machining the workpiece immediately after replacing the tooth cutting cutter attached to the tooth cutting cutter holder, instead of the axial phase adjustment step, the phase between the tooth of the gear to be cut and the chamfering cutter is readjusted to a predetermined phase, and the rotational phase between the workpiece spindle and the tool spindle stored in the phase storage step is updated to the rotational phase between the workpiece spindle and the tool spindle at the time of the readjustment. A method for manufacturing a gear, characterized by the above.

4. A method for manufacturing a gear according to claim 1, The chamfering cutter holder includes a phase determining device that is pressed to one side by an elastic force and is provided so as to be reciprocally movable in the pressing direction. In the phase adjustment step, while holding the chamfering cutter holder at a predetermined position and making the workpiece spindle rotatable, the workpiece spindle is moved so that the tooth of the gear to be cut is pressed by the phase determining device and the workpiece spindle rotates, and the phase between the tooth of the gear to be cut and the chamfering cutter is adjusted to a predetermined phase. A method for manufacturing a gear, characterized by the above.

5. A method for manufacturing a gear according to any one of claims 1 to 4, The tooth cutting cutter holder and the tool spindle are always assembled in the same phase. The chamfering cutter holder and the tool spindle are configured to be always assembled in the same phase. A method for manufacturing a gear, characterized by the above.

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