Tooth groove processing method and tooth groove processing device

Abstract

This invention relates to a tooth groove machining method and a tooth groove machining apparatus. The method comprises the following steps: when the reference point of a predetermined tooth groove of a workpiece is offset along the circumference of the workpiece, the offset angle is defined as a phase correction angle in the tooth turning process; the intersection angle between the parallel line of the central axis of the workpiece and the central axis of the cutting tool is set as a predetermined intersection angle; the phase correction angle is set as a first phase correction angle; the first tooth flank is machined using the cutting tool and the tooth turning process; the intersection angle is the same as the predetermined intersection angle; the phase correction angle is set as a second phase correction angle different from the first phase correction angle; the second tooth flank is machined using the same cutting tool as the cutting tool used to machine the first tooth flank and the tooth turning process.

Description

Technical Field

[0001] The invention relates to a tooth groove processing method and a tooth groove processing device for processing a tooth groove. Background Art

[0002] Japanese Patent Publication No. 2019-018335, Japanese Patent Publication No. 2016-093882, Japanese Patent Publication No. 2019-018334 and Japanese Patent Publication No. 2018-079558 describe a tooth groove processing method and a tooth groove processing device for processing the tooth groove of the internal teeth of the sleeve in the synchronous meshing mechanism of the vehicle transmission by gear skiving. The gear skiving can also be applied to the tooth groove processing of the external teeth of the synchronous cone in the synchronous meshing mechanism. The left and right tooth flanks of the tooth groove of the external teeth of the synchronous cone are formed into a cone shape that is symmetrical in the tooth line direction. That is, the opposing distance between adjacent tooth flanks increases as the axial direction is advanced.

[0003] When the tooth grooves of the external teeth of the synchronous cone are processed by gear turning, the right tooth side surface is processed by a gear cutting tool for the right tooth side surface, and the left tooth side surface is processed by a gear cutting tool for the left tooth side surface. In this case, two types of gear cutting tools are required, so there is a tendency for tool costs to increase. In addition, there is a concern that processing errors will occur due to tool replacement from the gear cutting tool for the right tooth side surface to the gear cutting tool for the left tooth side surface. In addition, when transferring from processing on the right tooth side surface to processing on the left tooth side surface, it is necessary to change the intersection angle of the tooth groove processing (the angle at which a line parallel to the center axis of the workpiece intersects with the center axis of the tool), so there is a tendency for the production cycle time to increase.

[0004] It is also considered that the tapered right tooth side and left tooth side of the tooth groove of the external tooth of the synchronous cone are machined by a single gear cutting tool. As described above, when machining is performed by using different left and right gear cutting tools, the tool torsion angles of the respective gear cutting tools may be different angles. However, when machining is performed by a single gear cutting tool, the tool torsion angle of the gear cutting tool is 0°.

[0005] Here, in order to smoothly engage and disengage the external teeth of the synchronous cone with the internal teeth of the sleeve, the cone angles of the right and left tooth sides of the tooth groove become relatively small. Therefore, when a gear cutting tool is used for processing, the tool torsion angle is shared at 0°, and the cross angle becomes an angle corresponding to the small cone angle, and the cross angle also becomes a relatively small angle along with the cone angle. Moreover, if the cross angle is a small angle, there is a problem that the cutting speed of the gear cutting tool decreases and the tool wear increases. In addition, even with this gear cutting tool, when transferring from the processing of the right tooth side surface to the processing of the left tooth side surface, the cross angle needs to be changed, so there is a trend of increasing the production cycle time. Summary of the invention

[0006] The object of the present invention is to provide a tooth groove processing method and a tooth groove processing device which can ensure a sufficiently large crossing angle for processing using a gear cutting tool even when the taper angle of the tooth groove is small, and can process the opposite tooth side surfaces of the tooth groove separately without changing the crossing angle.

[0007] A tooth groove processing method for processing a tooth groove on a workpiece by gear skiving using a gear cutting tool, wherein the workpiece is configured such that a first tooth side surface of the tooth groove has a first taper angle relative to a line parallel to the center axis of the workpiece, and a second tooth side surface in the tooth groove opposite to the first tooth side surface has a second taper angle different from the first taper angle. The tooth groove processing method comprises the following steps: when a reference point of a predetermined tooth groove of the workpiece is offset along the circumferential direction of the workpiece, an offset angle is defined as a phase correction angle in the gear skiving, an intersection angle between a line parallel to the center axis of the workpiece and the center axis of the gear cutting tool is set as a predetermined intersection angle, the phase correction angle is set as a first phase correction angle, the first tooth side surface is processed by the gear cutting tool through the gear skiving, the intersection angle is made the same as the predetermined intersection angle, the phase correction angle is set as a second phase correction angle different from the first phase correction angle, and the second tooth side surface is processed by the gear skiving using the same gear cutting tool as the gear cutting tool used to process the first tooth side surface.

[0008] A tooth groove processing device for processing a tooth groove on a workpiece by gear skiving using a gear cutting tool, wherein the workpiece is configured such that a first tooth side surface of the tooth groove has a first taper angle relative to a parallel line of the center axis of the workpiece, a second tooth side surface in the tooth groove opposite to the first tooth side surface has a second taper angle different from the first taper angle, and when a reference point of a predetermined tooth groove of the workpiece is offset along the circumferential direction of the workpiece, the offset angle is defined as a phase correction angle in the gear skiving. The tooth groove processing device includes a control unit, and the control unit is configured such that an intersection angle of a parallel line of the center axis of the workpiece and the center axis of the gear cutting tool is set to a predetermined intersection angle, the phase correction angle is set to a first phase correction angle, and the first tooth side surface is processed by the gear cutting tool through the gear skiving, the intersection angle is made equal to the predetermined intersection angle, and the phase correction angle is set to a second phase correction angle different from the first phase correction angle, and the second tooth side surface is processed by the gear skiving using the same gear cutting tool as the gear cutting tool used to process the first tooth side surface.

[0009] According to the tooth groove processing method and tooth groove processing device of the present invention, when processing the first tooth side surface of the tooth groove, the reference point of the first tooth side surface is offset by the first phase correction angle along the circumference of the workpiece, and when processing the second tooth side surface, the reference point of the second tooth side surface is offset by the second phase correction angle along the circumference of the workpiece. Thus, even when the taper angle of the tooth groove is small, a gear cutting tool can be used to ensure a sufficiently large intersection angle for processing. Therefore, tool wear can be reduced and tool costs can be suppressed. In addition, the opposite tooth side surfaces of the tooth groove can be processed separately without changing the intersection angle. Therefore, the production cycle time can be reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It is a figure which shows the structure of the tooth groove processing device.

[0011] Figure 2A This is a diagram of the setting of the intersection angle between the workpiece and the gear cutting tool in gear turning, viewed from the radial direction of the gear cutting tool.

[0012] Figure 2B It is viewed from the center axis of the gear cutting tool. Figure 2A .

[0013] Figure 3A This is a diagram for explaining the action of gear cutting, and is a diagram viewed along the radial direction of the gear cutting tool.

[0014] Figure 3B It is observed along the central axis of the gear cutting tool. Figure 3A .

[0015] Figure 4A This is a diagram showing a portion of an external gear of a synchronous bevel formed by gear skiving.

[0016] Figure 4B Observed along the radial direction of the external gear Figure 4A .

[0017] Figure 5A It is a figure which shows a gear cutting tool.

[0018] Figure 5B Observed along the radial direction Figure 5A A partial cross-sectional view of the blade of a gear cutting tool.

[0019] Fig. 6A The diagram is for explaining the movement of a gear cutting tool in gear cutting, and is a diagram viewed in the radial direction of a workpiece.

[0020] Figure 6B This is a diagram for explaining the phase correction angle when machining a groove in a bilaterally symmetrical tapered shape, and is a diagram observed along the radial direction of the workpiece.

[0021] Figure 6CThis is a diagram for explaining the phase correction angle when machining a groove having an asymmetric tapered shape, and is a diagram observed along the radial direction of the workpiece.

[0022] Fig. 7A It is a diagram for explaining the correction angle of the helical gear and is a perspective view showing a reference cylinder.

[0023] Figure 7B yes Fig. 7A A cross-sectional view perpendicular to the axial direction at the position of ΔL in the reference cylinder.

[0024] Fig. 8A This is a diagram showing a state in which there is no cutting residue in tooth groove machining, as viewed along the radial direction of the workpiece.

[0025] Figure 8B This is a diagram showing a state where cutting residue remains during tooth groove machining, as viewed along the radial direction of the workpiece.

[0026] Fig. 9 It is a diagram for explaining the calculation of each machining start position of the right tooth side surface and the left tooth side surface in the reference tooth groove.

[0027] Fig. 10A This is a diagram showing a bilaterally symmetrical cone shape when viewed along the radial direction of the workpiece.

[0028] Fig. 10B Yes means Fig. 10A A diagram of an example of the specifications of the tooth surface.

[0029] Fig. 10C In this embodiment, the conventional example is compared with Fig. 10A Diagram of the machining conditions when groove machining is performed on a shape of .

[0030] Fig.11A This is a diagram showing a tapered shape that is asymmetric left and right when viewed along the radial direction of the workpiece.

[0031] Fig. 11B Yes means Fig.11A A diagram of an example of the specifications of the tooth surface.

[0032] Fig. 11C In this embodiment, the comparison between the present embodiment and the prior art is Fig.11A Diagram of the machining conditions when groove machining is performed on a shape of .

[0033] Fig.12 It is a diagram showing the configuration of a machining control unit of a tooth groove machining device.

[0034] Fig.13 This is a flowchart for explaining the operation of the machining control unit when the reference tooth groove is not machined.

[0035] Fig.14AThis is a diagram showing a state where the right tooth side surface is machined when no reference tooth groove is machined, and is a diagram viewed in the radial direction of the workpiece.

[0036] Fig. 14B This is a diagram showing the calculation of the machining start position of the left tooth side surface when the reference tooth groove is not machined, and is a diagram observed in the radial direction of the workpiece.

[0037] Fig. 14C This is a diagram showing a state where the left tooth side surface is machined when no reference tooth groove is machined, and is a diagram viewed in the radial direction of the workpiece.

[0038] Fig.15A This is a flowchart for explaining the first half of the operation of the machining control unit when machining a reference tooth groove.

[0039] Fig. 15B This is a flowchart for explaining the second half of the operation of the machining control unit when machining the reference tooth groove.

[0040] Fig.16A This is a diagram showing reference points for left and right tooth side surfaces for calculating machining start positions of left and right tooth side surfaces when machining a reference tooth groove, and is a diagram observed in the radial direction of the workpiece.

[0041] Fig. 16B This is a diagram showing a state where the right tooth side surface is machined from the machining start position of the right tooth side surface when machining the reference tooth groove, and is a diagram viewed in the radial direction of the workpiece. DETAILED DESCRIPTION

[0042] (1. Structure of Tooth Groove Processing Device 10)

[0043] Reference Figure 1 The structure of the tooth groove processing device is described. Figure 1 As shown, the tooth groove machining device 10 is, for example, a five-axis machining center having three linear axes and two rotation axes as driving axes for changing the relative position and posture of the workpiece W and the gear cutting tool T.

[0044] In this example, the tooth groove processing device 10 has three orthogonal axes (X axis, Y axis, Z axis) as linear axes, and a B axis and a Cw axis as rotation axes. In this example, the B axis is a rotation axis around the Y axis, and the Cw axis is a rotation axis around the center axis of the workpiece W. In addition, the tooth groove processing device 10 has a Ct axis which is a rotation axis around the center axis of the gear cutting tool T, and if the Ct axis is included, it becomes a six-axis machining center.

[0045] The tooth groove processing device 10 includes a tool spindle 11 that supports the gear cutting tool T and enables it to rotate around the Ct axis and move in the Y-axis direction and the Z-axis direction. In addition, the tooth groove processing device 10 includes a workpiece spindle 12 that supports the workpiece W and enables it to rotate around the Cw axis, and can be rotated around the B axis and can be moved in the X-axis direction.

[0046] The tooth groove processing device 10 includes a processing control unit 13 for controlling the operation of processing the tooth groove. In this example, the processing control unit 13 controls the processing of the tooth groove on the workpiece W by gear cutting. In addition, it is not limited to the above structure, as long as the tool spindle 11 and the workpiece spindle 12 can move relative to each other.

[0047] (2. Gear machining)

[0048] Reference Figure 2A , Figure 2B , Figure 3A as well as Figure 3B The gear cutting process is described below. Figure 2A as well as Figure 2B As shown, the gear cutting process is in a state where the center axis Ct of the gear cutting tool T has an intersection angle θ with respect to an axis parallel to the center axis Cw of the workpiece W. In addition, when viewed from the X-axis direction, the center axis Ct of the gear cutting tool T is parallel to the center axis Cw of the workpiece W.

[0049] Moreover, if Figure 3A as well as Figure 3B As shown, the method is to synchronize the rotation of the workpiece W around the center axis Cw of the workpiece W (clockwise in the figure) and the rotation of the gear cutting tool T around the center axis Ct of the gear cutting tool T (counterclockwise in the figure), and to transport the gear cutting tool T in the direction of the center axis Cw of the workpiece W relative to the workpiece W, thereby processing the tooth groove of the workpiece W. In the gear turning process, the tooth groove portion of the workpiece W is processed by the gear cutting tool T only once during one rotation of the workpiece W.

[0050] (3. Workpiece W)

[0051] In the tooth groove processing device 10 of this embodiment, a tooth groove processing is performed in a synchronous meshing mechanism of a transmission of an automobile. Figure 4A as well as Figure 4B The external gear G of the synchronous cone SC meshes with the internal teeth of a sleeve (not shown), and the tooth grooves Gg (teeth Gt) of the external gear G of the synchronous cone SC are formed into a tapered shape to prevent the gear from falling off.

[0052] That is, the right tooth side surface Gsr (first tooth side surface) and the left tooth side surface Gsl (second tooth side surface) of the tooth groove Gg of the external gear G of the synchronizer cone SC are formed into a left-right symmetrical cone shape with respect to the parallel line of the center axis Cw. Moreover, the right tooth side surface Gsr of the tooth groove Gg has a cone angle Φ with respect to the parallel line of the center axis Cw. R (first taper angle) and the taper angle Φ of the left tooth side surface Gsl with respect to the parallel line of the central axis Cw L The second taper angle is set to a relatively small angle (eg, 3°) so that the above-mentioned meshing can be released smoothly. In addition, the right tooth side surface Gsr and the left tooth side surface Gsl of the tooth groove Gg are separated by an angle σ around the central axis Cw of the workpiece W.

[0053] In the following description, the angles of the right tooth side surface Gsr and the left tooth side surface Gsl are indicated by positive in the clockwise direction and negative in the counterclockwise direction relative to the parallel line of the central axis Cw. Figure 4B As shown, when the tapered side of the tapered tooth groove Gg is located at the bottom of the figure, the right tooth side surface Gsr is inclined clockwise relative to the parallel line of the central axis Cw, so the taper angle Φ of the right tooth side surface Gsr is R In addition, the left tooth side surface Gsl is inclined counterclockwise relative to the parallel line of the central axis Cw, so the taper angle Φ of the left tooth side surface Gsl is L is negative.

[0054] The shape of the tooth groove Gg that can be machined by the tooth groove machining device 10 of this example is not limited to a parallel line with respect to the central axis Cw, a bilaterally symmetrical tapered shape (the taper angle φ of the right tooth side surface Gsr with respect to the parallel line of the central axis Cw is φ 2. R , the taper angle Φ of the parallel line with the left tooth side surface Gsl relative to the central axis Cw L The absolute value of the same shape but different in sign) can also be a cone shape that is asymmetric left and right relative to a parallel line of the central axis Cw (the cone angle Φ of the right side surface Gsr relative to a parallel line of the central axis Cw R , the taper angle Φ of the parallel line with the left tooth side surface Gsl relative to the central axis Cw L The absolute value and the shape of the positive and negative are different).

[0055] (4. Gear cutting tool T)

[0056] like Figure 5A As shown, the tool edge Tc of the gear cutting tool T is a truncated cone having a plurality of edges Tcc on the outer periphery, and the tool axis Ta of the gear cutting tool T is formed as an integral part on the small diameter end surface Tb. The shape of the edge Tcc of the large diameter end surface Td of the tool edge Tc of the gear cutting tool T is formed in an involute curve shape in this example.

[0057] Moreover, if Figure 5B As shown, on the cutting edge Tcc, a rake angle of an inclination angle γ relative to a plane perpendicular to the center axis Ct is provided on the large diameter end surface Td side, and a secondary relief angle of an inclination angle δ relative to a straight line parallel to the center axis Ct is provided on the tool peripheral surface side. When the straight line Le passing through the center of the cutting edge lines Te on both sides is viewed from the radial direction, the cutting edge Tcc has a torsion angle of an inclination angle β relative to the center axis Ct.

[0058] (5. Design method of gear cutting tool T)

[0059] The design method of the gear cutting tool T will be described. As described in the problem to be solved, if the intersection angle θ in tooth groove machining is small, there is a problem that the cutting speed of the gear cutting tool T is slowed down and tool wear is increased.

[0060] The cross angle θ that can set the cutting speed of the gear cutting tool T to an appropriate value in the gear cutting process is preferably about 20° to about 30° according to the actual processing effect. Therefore, the torsion angle β of the gear cutting tool T is set to a value based on the cross angle θ (about 20° to about 30°). The other tool specifications of the gear cutting tool T are set according to the gear specifications of the external gear turning G. And, based on the other tool specifications of the gear cutting tool T after setting, the gear cutting tool T is designed.

[0061] In addition, since the processing object is an external gear G, interference between the gear cutting tool T and the workpiece W during processing can be avoided, but the gear cutting tool T is designed in a manner that can avoid interference with a fixture or the like that supports the workpiece W. In addition, internal teeth can also be processed in the same manner as the processing object. In this case, the gear cutting tool T is designed in a manner that can avoid interference between the gear cutting tool T and the workpiece W during processing.

[0062] (6. Key points of tooth groove processing)

[0063] Usually, in the tooth groove processing of the helical gear, the torsion angle of the right tooth side surface and the left tooth side surface of the tooth groove is the same, so a correction angle is used for processing. In contrast, in the conical tooth groove processing of this example, the taper angle Φ of the right tooth side surface Gsr of the tooth groove Gg is R Cone angle Φ with left tooth side Gsl L different, so use the cone angle Φ R , Φ L The matching correction angle (in this case, called the phase correction angle) is used for processing.

[0064] The phase correction angle used in the processing of the conical tooth groove in this example is different from the correction angle used in the processing of the tooth groove of the helical gear, and cannot be applied to the processing of the tooth groove of the helical gear. Specifically, when the correction angle is used, the tooth profile of the helical gear can be processed into a high-precision involute shape regardless of the size of the torsion angle of the tooth groove (tooth) of the helical gear. On the other hand, when the phase correction angle is used, the tooth profile of the external gear G is processed into a shape deformed from the involute shape.

[0065] However, the synchronous cone SC of this example only needs to have a relatively small taper angle of the tooth groove Gg of the external gear G to be synchronized with the sleeve. Therefore, the external gear G does not require the same processing accuracy as the helical gear, and even if the tooth profile of the external gear G is processed into a shape deformed from the involute shape, no particular problem will occur. Accordingly, the phase correction angle used in the processing of the tapered tooth groove of this example cannot be applied to the processing of the tooth groove of the helical gear.

[0066] The phase correction angle used in the tapered tooth groove processing of this example is defined as follows. Fig. 6A As shown, in the gear cutting process in which the gear cutting tool T moves relatively from the initial position Ps to the final position Pe (thickness ΔZ of the workpiece W) along the center axis Cw direction of the workpiece W, the position of the cutting edge Tcc of the gear cutting tool T is at the same position in both the initial position Ps and the final position Pe.

[0067] Here, a reference tooth groove (specified tooth groove) having a reference tooth side surface reaching the final position Pe from a processing reference point Pb different from the initial position Ps is set at a portion that becomes the tooth groove Gg of the external gear G. The reference tooth side surface in the reference tooth groove has a reference angle. And the reference angle is the taper angle φ of the right tooth side surface Gsr. R Cone angle Φ with left tooth side Gsl L The intermediate value of . Thus, it is easy to determine the machining conditions of the right tooth side surface Gsr and the left tooth side surface Gsl that are symmetrical. The reference tooth groove varies depending on the shape of the tooth groove Gg, and the following will explain each case.

[0068] First, the shape of the tooth groove Gg is a tapered shape that is bilaterally symmetrical with respect to a parallel line to the central axis Cw (the taper angle Φ of the right tooth side surface Gsr is R Cone angle Φ with left tooth side Gsl L In this example, the reference angle of the reference tooth side surface is set to the taper angle Φ of the right tooth side surface Gsr. R Cone angle Φ with left tooth side Gsl L The median value of , so it becomes 0°. Therefore, if Figure 6B As shown, the reference tooth side surface Gsb reaches the final position Pe from the initial position Ps. That is, the machining reference point Pb (reference point) coincides with the initial position Ps.

[0069] Moreover, when machining the tapered tooth groove Gg, for example, the right tooth side surface Gsr, it is necessary to offset the machining reference point Pb in the circumferential direction. That is, it is necessary to offset the machining reference point Pb in the circumferential direction from the initial position Ps by the offset amount ΔC. The rotation offset angle of the workpiece W relative to the gear cutting tool T (synchronous) at this time is defined as the phase correction angle in the gear cutting process. In addition, when offsetting in the circumferential direction, the machining position of the gear cutting tool T is accompanied by the movement of the workpiece W in the direction of the center axis Cw.

[0070] Next, the shape of the tooth groove Gg is a tapered shape that is asymmetric left and right with respect to a parallel line to the central axis Cw (the taper angle Φ of the right tooth side surface Gsr is R and the cone angle Φ of the left tooth side Gsl L In this example, the reference angle of the reference tooth side surface is set to the cone angle Φ of the right tooth side surface Gsr. R Cone angle Φ with left tooth side Gsl L The median value of , so it becomes a value other than 0°. Therefore, if Figure 6C As shown, the reference tooth side surface Gsb reaches the final position Pe from the machining reference point Pb (reference point) which is offset from the initial position Ps by the offset amount ΔCC1 in the circumferential direction. When offset in the circumferential direction, the machining position of the gear cutting tool T moves along the workpiece W in the direction of the center axis Cw.

[0071] Moreover, when processing the tapered tooth groove Gg, for example, the right tooth side surface Gsr, it is necessary to further offset the processing reference point Pb in the circumferential direction. That is, it is necessary to further offset the processing reference point Pb in the circumferential direction by an offset amount ΔCC2. The rotation offset angle of the workpiece W relative to the gear cutting tool T (synchronous) at this time is defined as the phase correction angle in the gear cutting process. In addition, when offsetting in the circumferential direction, the processing position of the gear cutting tool T is accompanied by the movement of the workpiece W in the direction of the center axis Cw.

[0072] Here, usually Fig. 7A As shown, regarding the helical gear, the helical line r having a torsion angle ε on the reference cylinder M rotates one circle from the starting point qs to the end point qe on the reference cylinder M, and advances a lead L in the central axis direction of the reference cylinder M.

[0073] Therefore, the cross section of the cylinder when advancing an arbitrary distance ΔL along the central axis of the reference cylinder M (refer to Figure 7B ), the angle formed by the point q on the helical line r, the center Cm of the cylinder, and the projection point qss of the starting point qs on the cylinder section is the correction angle R. The correction angle R can be calculated using formula (1). In formula (1), mh is the module of the helical gear, and Th is the number of teeth of the helical gear.

[0074] [Formula 1]

[0075]

[0076] Formula (2) using formula (1) is a formula for calculating the phase correction angle A+α for machining the right tooth side surface Gsr of the tooth groove Gg in this example. In formula (2), A is the reference phase correction angle of the reference tooth side surface Gsb, A+α is the phase correction angle (first phase correction angle) of the right tooth side surface Gsr, ψ is the reference angle of the reference tooth side surface, and Φ R is the taper angle of the right tooth side surface Gsr, ΔZ is the movement amount of the gear cutting tool T from the initial position Ps to the final position Pe, m is the module of the external gear G, and T is the number of teeth of the external gear G.

[0077] Moreover, the rotation angle of the central axis Cw of the workpiece W is corrected by using the phase correction angle A+α, so that the right tooth side surface Gsr of the tooth groove Gg can be processed. In addition, in this example, the reference phase correction angle A is 0. The above can also be applied to the calculation of the phase correction angle A-α (second phase correction angle) of the left tooth side surface Gsl of the tooth groove Gg.

[0078] [Formula 2]

[0079]

[0080] The value obtained by subtracting the reference phase correction angle A from the phase correction angle A+α of the right tooth side surface Gsr and the value obtained by subtracting the reference phase correction angle A from the phase correction angle A-α of the left tooth side surface Gsl have opposite signs and the same absolute values. Thus, the right and left tooth side surfaces Gsl and the left tooth side surface Gsl that are symmetrical with each other can be machined with high precision.

[0081] (7. Problems with tooth groove processing)

[0082] In the above-mentioned tooth groove processing method, the relationship between the maximum tooth groove width of the tooth groove Gg of the external gear G (the tooth groove width when the tooth width of the tooth Gt becomes the smallest) and the blade width of the blade Tcc of the gear cutting tool T becomes an issue. Fig. 8A As shown in FIG. 1 , when the maximum tooth groove width hg is smaller than twice the blade width ht, only the right tooth side surface Gsr and the left tooth side surface Gsl can be processed to achieve a state where there is no cutting residue in the tooth groove Gg. Figure 8B As shown, when the maximum tooth groove width hg is larger than twice the blade width ht, a triangular prism-shaped cutting residue B exists in the tooth groove Gg by machining only the right tooth side surface Gsr and the left tooth side surface Gsl.

[0083] In this case, before machining the right tooth side surface Gsr and the left tooth side surface Gsl, it is necessary to perform groove machining of the reference tooth groove Gb having the reference tooth side surface Gsb with respect to the portion of the outer periphery of the workpiece W that becomes the tooth groove Gg. The reference angle ψ of the reference tooth side surface Gsb is set to the taper angle Φ of the right tooth side surface Gsr. R Cone angle Φ with left tooth side Gsl L The middle value of .

[0084] Moreover, if Fig. 9 As shown, a position detection sensor such as an eddy current contact sensor (not shown) is used as a reference point Qr for the right tooth side surface to detect the intersection of the outer periphery Ws of the end surface Wf on the processing start side of the workpiece W and the reference right tooth side surface Gsbr of the reference tooth groove Gb. Moreover, the processing start position of the right tooth side surface Gsr is calculated based on the offset of the formation position of the right tooth side surface Gsr relative to the reference point Qr for the right tooth side surface. In this way, the accuracy of the processing start position of the right tooth side surface Gsr can be improved. In addition, the gear cutting tool T is positioned at the processing start position of the right tooth side surface Gsr to process the right tooth side surface Gsr.

[0085] Similarly, the intersection of the outer periphery Ws of the end face Wf on the processing start side of the workpiece W and the reference left tooth side surface Gsb1 of the reference tooth groove Gb is detected as the reference point Q1 for the left tooth side surface. Moreover, the processing start position of the left tooth side surface Gsl is calculated based on the offset of the formation position of the left tooth side surface Gsl relative to the reference point Q1 for the left tooth side surface. Thus, the accuracy of the processing start position of the left tooth side surface Gsl can be improved. Moreover, the gear cutting tool T is positioned at the processing start position of the left tooth side surface Gsl, and the processing of the left tooth side surface Gsl is performed. Thus, a state can be achieved where there is no cutting residue B in the tooth groove Gg. In addition, the groove processing of the reference tooth groove Gb can also be performed after the processing of the right tooth side surface Gsr and the left tooth side surface Gsl.

[0086] (8. Tooth processing conditions)

[0087] The tooth groove processing method determines the processing conditions for tooth groove processing by gear cutting, and performs tooth groove processing by gear cutting based on the determined processing conditions. In this example (a case where the reference tooth groove Gb is not processed (the first example), a case where the reference tooth groove Gb is processed (the second example)), a case where processing is performed using two existing gear cutting tools (the first comparative example), and a case where processing is performed using one existing gear cutting tool (the second comparative example), specific examples of tooth groove processing conditions are described.

[0088] First, if Fig. 10A As shown, the shape of the tooth groove Gg is a tapered shape that is symmetrical with respect to the parallel line of the central axis Cw (the taper angle Φ of the right tooth side surface Gsr is RCone angle Φ with left tooth side Gsl L The following describes the case where the absolute values ​​of the two are the same but the positive and negative shapes are different. Fig. 10B As shown in the figure, as the specification of the tooth surface of the tooth groove Gg of the external gear G, the cone angle Φ of the right tooth side surface Gsr R is +3°, the cone angle Φ of the left tooth side Gsl L is -3°, the reference angle ψ of the reference tooth groove Gb is the cone angle Φ of the right tooth side surface Gsr R Cone angle Φ with left tooth side Gsl L The median value of , so it becomes 0°.

[0089] like Fig. 10C As shown, the type of tool used to process the right tooth side surface Gsr and the left tooth side surface Gsl is common in the first example and the second example, and is used for the right and left in the first comparative example, and is common in the second comparative example. The intersection angle θ, tool torsion angle β, and phase correction angle when processing the right tooth side surface Gsr are 20°, 20°, and A1+α1 (A1=0) in the first example and the second example, 20°, 23°, and B (B≠0) in the first comparative example, and 3°, 0°, and C (C≠0) in the second comparative example. The crossing angle θ, tool torsion angle β, and phase correction angle when processing the left tooth side surface Gsl are 20°, 20°, and A1-α2 (A1=0, α1=α2) in the first example and the second example; in the first comparison example, they are -20°, -23°, and -B (B≠0); and in the second comparison example, they are -3°, 0°, and -C (C≠0).

[0090] Therefore, in the first example and the second example, and the second comparative example, compared with the first comparative example, since only one gear cutting tool is used, it is possible to suppress the increase in tool cost and the occurrence of processing errors caused by tool replacement. In addition, in the first example and the second example, compared with the second comparative example, the crossing angle can be increased and the crossing angle does not need to be changed, so it is possible to suppress the increase in tool wear and cycle time.

[0091] Next, if Fig.11A As shown, the shape of the tooth groove Gg is a tapered shape that is asymmetric left and right with respect to a parallel line of the central axis Cw (the taper angle Φ of the right tooth side surface Gsr is R Cone angle Φ with left tooth side Gsl L The absolute value of and the shape of positive and negative are explained. Fig. 11B As shown in the figure, as the specification of the tooth surface of the tooth groove Gg of the external gear G, the cone angle Φ of the right tooth side surface Gsr R is +3°, the cone angle Φ of the left tooth side Gsl L is -2°, the reference angle ψ of the reference tooth groove Gb is the cone angle Φ of the right tooth side surface Gsr RCone angle Φ with left tooth side Gsl L The median value is therefore +0.5°.

[0092] like Fig. 11C As shown, the type of tool used to process the right tooth side surface Gsr and the left tooth side surface Gsl is common in the first example and the second example, and is used for the right and left in the first comparative example, and is common in the second comparative example. The cross angle θ, tool torsion angle β, and phase correction angle when processing the right tooth side surface Gsr are 20.5°, 20.5°, and A2+α3 (A2≠0) in the first example and the second example, and are 20°, 20°, and A3+α5 (A3=0) in another example of the first example and the second example, 20°, 23°, and E (E≠0) in the first comparative example, and 3°, 0°, and G (G≠0) in the second comparative example. The crossing angle θ, tool torsion angle β, and phase correction angle when processing the left tooth side surface Gsl are 20.5, 20.5°, and A2-α4 (A2≠0, α3=α4) in the first example and the second example. In addition, they are 20°, 20°, and A3-α6 (A3=0, α5≠α6) in the first example and another example of the second example. In the first comparison example, they are -20°, -22°, and -F (F≠0). In the second comparison example, they are -2°, 0°, and -H (H≠0).

[0093] Therefore, compared with the first comparative example, the first example, the second example, and the second comparative example can use only one gear cutting tool, so the tool cost increase and the occurrence of processing errors caused by tool replacement can be suppressed. In addition, compared with the second comparative example, the first example and the second example can increase the intersection angle and do not need to change the intersection angle, so the increase in tool wear and cycle time can be suppressed.

[0094] (9. Configuration of Processing Control Unit 13)

[0095] like Fig.12 As shown, the processing control unit 13 of the tooth groove processing device 10 includes a reference processing condition determination unit 14, a first tooth side surface processing condition determination unit 15, a second tooth side surface processing condition determination unit 16, a reference tooth groove processing control unit 17, a first tooth side surface processing control unit 18, and a second tooth side surface processing control unit 19. The reference processing condition determination unit 14 determines reference processing conditions for processing a reference tooth groove Gb having a reference angle ψ by gear cutting, using a crossing angle θ as a predetermined crossing angle and a phase correction angle as a reference phase correction angle different from the phase correction angle of the right tooth side surface Gsr and the phase correction angle of the left tooth side surface Gsl.

[0096] The first tooth side surface machining condition determination unit 15 determines the right tooth side surface machining condition, which is a condition for machining the right tooth side surface Gsr by gear skiving, based on the reference machining condition determined by the reference machining condition determination unit 14, with the crossing angle θ being the predetermined crossing angle and the phase correction angle being the phase correction angle (first phase correction angle) of the right tooth side surface Gsr. The second tooth side surface machining condition determination unit 16 determines the left tooth side surface machining condition, which is a condition for machining the left tooth side surface Gsl by gear skiving, based on the reference machining condition determined by the reference machining condition determination unit 14, with the crossing angle θ being the predetermined crossing angle and the phase correction angle being the phase correction angle (second phase correction angle) of the left tooth side surface Gsl.

[0097] The reference tooth groove machining control unit 17 uses the crossing angle θ as the prescribed crossing angle and the phase correction angle as the reference phase correction angle based on the reference machining condition determined by the reference machining condition determination unit 14, and machines the reference tooth groove Gb having the reference angle ψ by gear skiving using the gear cutting tool T. The first tooth flank machining control unit 18 uses the right tooth flank machining condition determined by the first tooth flank machining condition determination unit 15, and machines the right tooth flank Gsr by gear skiving using the same gear cutting tool T as the gear cutting tool T used to machine the reference tooth groove Gb, so that the crossing angle θ becomes the same as the prescribed crossing angle and the phase correction angle becomes the phase correction angle of the right tooth flank Gsr.

[0098] The second tooth side surface processing control unit 19 makes the crossing angle θ the same as the above-mentioned specified crossing angle based on the left tooth side surface processing condition determined by the second tooth side surface processing condition determination unit 16, and uses the phase correction angle as the phase correction angle of the left tooth side surface Gsl which is different from the phase correction angle of the right tooth side surface Gsr, and uses the same gear cutting tool T as the gear cutting tool T for processing the right tooth side surface Gsr to process the left tooth side surface Gsl through gear turning.

[0099] According to the tooth groove processing device 10, when processing the right tooth side surface Gsr of the tooth groove Gg, the processing reference point Pb of the right tooth side surface Gsr is offset in the circumferential direction of the workpiece W by the phase correction angle of the right tooth side surface Gsr. In addition, when processing the left tooth side surface Gsl, the processing reference point of the left tooth side surface Gsl is offset in the circumferential direction of the workpiece W by the phase correction angle of the left tooth side surface Gsl. In this way, the processing point is offset relative to the tooth line (tooth surface), so that even when the taper angle Φ of the tooth groove Gg is small, a gear cutting tool T (without changing the tool) can be used to ensure a sufficiently large intersection angle θ for processing. Therefore, tool wear can be reduced and tool costs can be suppressed. In addition, the opposing tooth side surfaces Gsr and Gsl of the tooth groove Gg can be processed separately without changing the intersection angle θ. Therefore, the cycle time can be reduced.

[0100] (10. Operation of the Processing Control Unit 13)

[0101] As one of the operations of the processing control unit 13, refer to Fig.13 Flowchart and Figures 14A-14C The operation diagram of will explain the case where the reference tooth groove Gb is not machined. The machining control unit 13 determines right tooth side machining conditions such as a predetermined intersection angle θ for machining the right tooth side surface Gsr and a phase correction angle of the right tooth side surface Gsr (step S1, first tooth side surface machining condition determination process).

[0102] Furthermore, the machining control unit 13 determines the left tooth side machining conditions such as the predetermined intersection angle θ of the right tooth side machining conditions and the phase correction angle of the left tooth side Gsl for machining the left tooth side Gsl (step S2, second tooth side machining condition determination process). Furthermore, the machining control unit 13 sets a state based on the predetermined intersection angle θ (step S3).

[0103] Then, if Fig.14A As shown, the processing control unit 13 uses the phase correction angle of the right tooth side surface Gsr of the right tooth side surface processing condition to control the rotation of the workpiece W, and controls the relative movement of the synchronously rotating gear cutting tool T and the workpiece W along the direction of the center axis Cw of the workpiece W, and uses the gear cutting tool T to perform groove processing with the right tooth side surface Gsr on the workpiece W from any processing start position Pr (step S4, the first tooth side surface processing process).

[0104] The processing control unit 13 determines whether the groove processing with the right tooth side surface Gsr is completed (step S5). If the groove processing with the right tooth side surface Gsr is not completed (step S5: No), it returns to step S4 and repeats the above process. If the groove processing with the right tooth side surface Gsr is completed (step S5: Yes), the rotation of the workpiece W is stopped, and the relative movement of the gear cutting tool T and the workpiece W is stopped.

[0105] Moreover, if Fig. 14B As shown, the processing control unit 13 rotates the workpiece W in the direction of the arrow in the figure by the pre-stored separation angle σ of the opposing right tooth side surface Gsr and left tooth side surface Gsl of the workpiece W around the central axis Cw of the workpiece W, and calculates the processing start position Pl of the groove processing with the left tooth side surface Gsl. And, the gear cutting tool T is positioned at the calculated processing start position Pl of the groove processing with the left tooth side surface Gsl (step S6).

[0106] The processing control unit 13 maintains the above-mentioned specified intersection angle θ as it is, uses the phase correction angle of the left tooth side surface Gsl to control the rotation of the workpiece W, and controls the relative movement of the synchronously rotating gear cutting tool T and the workpiece W along the direction of the center axis Cw of the workpiece W, and uses the gear cutting tool T to process a groove having the left tooth side surface Gsl on the workpiece W (step S7, the second tooth side surface processing process).

[0107] The processing control unit 13 determines whether the processing of the groove having the left tooth side surface Gsl is completed (step S8). If the processing of the groove having the left tooth side surface Gsl is not completed (step S8: No), the process returns to step S7 and repeats the above process. If the processing of the groove having the left tooth side surface Gsl is completed (step S8: Yes), the rotation of the workpiece W is stopped, and the relative movement of the gear cutting tool T and the workpiece W is stopped, and all the processes are completed. In this way, a tapered tooth groove Gg without a cutting residue B in the tooth groove Gg can be obtained.

[0108] As the second operation of the processing control unit 13, refer to Figures 15A-15B Flowchart and Figures 16A-16B The operation diagram of the reference tooth groove Gb is explained. Fig.13 The same operations in the flowchart are marked with the same reference numerals and detailed descriptions are omitted. The machining control unit 13 determines reference machining conditions such as a predetermined intersection angle θ and a reference phase correction angle for machining the reference tooth groove Gb (step S11, reference machining condition determination process). Furthermore, the machining control unit 13 determines the right tooth side surface machining conditions and the left tooth side surface machining conditions (steps S1 and S2), and sets them to a state having the predetermined intersection angle θ (step S3).

[0109] The processing control unit 13 controls the rotation of the workpiece W based on the determined reference processing conditions using the phase correction angle of the reference tooth groove Gb, and controls the relative movement of the synchronously rotating gear cutting tool T and the workpiece W along the direction of the center axis Cw of the workpiece W, and processes the reference tooth groove Gb on the workpiece W using the gear cutting tool T from any processing start position (step S12, reference tooth groove processing process).

[0110] The processing control unit 13 determines whether the processing of the reference tooth groove Gb is completed (step S13). If the processing of the reference tooth groove Gb is not completed (step S13: No), it returns to step S12 and repeats the above process. If the processing of the reference tooth groove Gb is completed (step S13: Yes), the rotation of the workpiece W is stopped, and the relative movement of the gear cutting tool T and the workpiece W is stopped.

[0111] Moreover, if Fig. 15BAs shown, the processing control unit 13 detects the reference point Qr for the right tooth side surface and the reference point Ql for the left tooth side surface using a position detection sensor (not shown) (step S14). Moreover, the processing control unit 13 calculates the processing start position Pr of the right tooth side surface Gsr based on the reference point Qr for the right tooth side surface, and positions the gear cutting tool T at the processing start position Pr of the right tooth side surface Gsr (step S15). Moreover, the processing control unit 13 keeps the above-mentioned predetermined intersection angle θ as it is, and performs groove processing having the right tooth side surface Gsr on the workpiece W using the gear cutting tool T (step S4, the first tooth side surface processing step).

[0112] The processing control unit 13 determines whether the groove processing of the right tooth side surface Gsr is completed (step S5). If the groove processing of the right tooth side surface Gsr is not completed (step S5: No), it returns to step S4 and repeats the above process. If the groove processing of the right tooth side surface Gsr is completed (step S5: Yes), the rotation of the workpiece W is stopped, and the relative movement of the gear cutting tool T and the workpiece W is stopped.

[0113] Then, the machining control unit 13 calculates the machining start position of the left tooth side surface Gsl based on the reference point Ql for the left tooth side surface, and positions the gear cutting tool T at the machining start position of the left tooth side surface Gsl (step S16). Then, the machining control unit 13 keeps the above-mentioned predetermined intersection angle θ as it is, and performs groove machining having the left tooth side surface Gsl on the workpiece W using the gear cutting tool T (step S7, second tooth side surface machining process).

[0114] The processing control unit 13 determines whether the groove processing of the left tooth side surface Gsl is completed (step S8). If the groove processing of the left tooth side surface Gsl is not completed (step S8: No), it returns to step S7 and repeats the above process. If the groove processing of the left tooth side surface Gsl is completed (step S8: Yes), the rotation of the workpiece W is stopped, and the relative movement of the gear cutting tool T and the workpiece W is stopped, and all the processes are completed. According to this, a tapered tooth groove Gg without a cutting residue B in the tooth groove Gg can be obtained.

Claims

1. A tooth groove processing method, which is a tooth groove processing method for processing a tooth groove on a workpiece by a gear cutting tool through gear turning processing, characterized in that: The workpiece is configured such that a first tooth side surface of the tooth groove has a first taper angle relative to a line parallel to the central axis of the workpiece, and a second tooth side surface of the tooth groove opposite to the first tooth side surface has a second taper angle different from the first taper angle. The tooth groove processing method comprises the following steps: When the reference point of a predetermined tooth groove of the workpiece is shifted in the circumferential direction of the workpiece, the shift angle is defined as the phase correction angle in the gear cutting process. When the gear cutting tool is shifted in the circumferential direction, the machining position of the gear cutting tool is accompanied by the movement of the workpiece in the direction of the central axis. The first tooth side surface is machined by the gear cutting tool by setting the intersection angle between the parallel line of the central axis of the workpiece and the central axis of the gear cutting tool to a predetermined intersection angle and setting the phase correction angle to a first phase correction angle, thereby machining the first tooth side surface by the gear cutting tool and by the gear skiving process. The crossing angle is made equal to the predetermined crossing angle, and the phase correction angle is set to a second phase correction angle different from the first phase correction angle, so that the second tooth side surface is machined by the gear skiving process using the same gear cutting tool as the gear cutting tool used to machine the first tooth side surface, The middle value between the first cone angle and the second cone angle is defined as a reference angle. The crossing angle is made equal to the prescribed crossing angle, and the phase correction angle is set to a reference phase correction angle different from the first phase correction angle and the second phase correction angle, so that a reference tooth groove having the reference angle is machined by the gear skiving process using the same gear cutting tool as the gear cutting tool used to machine the first tooth side surface, The processing of the first tooth side surface and the processing of the second tooth side surface are performed after the processing of the reference tooth groove. The tool blade of the gear cutting tool has a plurality of blades on the periphery. When the maximum tooth groove width of the tooth groove is smaller than twice the blade width of the tool blade, the tooth groove is formed by machining only the first tooth side surface and the second tooth side surface.

2. The tooth groove processing method according to claim 1, characterized in that: The reference angle is a median value between the first cone angle and the second cone angle.

3. The tooth groove processing method according to claim 1, characterized in that: The above-mentioned reference angle is 0°.

4. The tooth groove processing method according to any one of claims 1 to 3, characterized in that: The following steps are also included: The middle value between the first cone angle and the second cone angle is defined as a reference angle. determining a reference machining condition, the reference machining condition being a condition for machining the tooth groove having the reference angle by the gear skiving machining, wherein the crossing angle is set to the predetermined crossing angle, and the phase correction angle is set to a reference phase correction angle different from the first phase correction angle and the second phase correction angle, A first tooth side surface machining condition is determined based on the reference machining condition, the first tooth side surface machining condition being a condition for machining the first tooth side surface by the gear skiving machining, and being configured such that the crossing angle is set to the predetermined crossing angle, and the phase correction angle is set to the first phase correction angle, determining a second tooth side surface machining condition based on the reference machining condition, the second tooth side surface machining condition being a condition for machining the second tooth side surface by the gear skiving machining, and being configured such that the crossing angle is set to the predetermined crossing angle, and the phase correction angle is set to the second phase correction angle, The processing of the first tooth side surface is performed based on the first tooth side surface processing conditions. The processing of the second tooth flank is performed based on the second tooth flank processing conditions.

5. The tooth groove processing method according to claim 4, characterized in that: A value obtained by subtracting the reference phase correction angle from the first phase correction angle and a value obtained by subtracting the reference phase correction angle from the second phase correction angle have opposite signs to each other, and the values ​​have the same absolute value to each other.

6. A tooth groove processing device, which uses a gear cutting tool to process tooth grooves on a workpiece by gear cutting, characterized in that: The workpiece is configured such that a first tooth side surface of the tooth groove has a first taper angle relative to a line parallel to the central axis of the workpiece, and a second tooth side surface of the tooth groove opposite to the first tooth side surface has a second taper angle different from the first taper angle. When the reference point of a predetermined tooth groove of the workpiece is shifted in the circumferential direction of the workpiece, the shift angle is defined as the phase correction angle in the gear cutting process. When the gear cutting tool is shifted in the circumferential direction, the machining position of the gear cutting tool is accompanied by the movement of the workpiece in the direction of the central axis. The middle value between the first cone angle and the second cone angle is defined as a reference angle. The tooth groove processing device includes a control unit, The control unit is composed of: The first tooth side surface is machined by the gear cutting tool by setting the intersection angle between the parallel line of the central axis of the workpiece and the central axis of the gear cutting tool to a predetermined intersection angle and setting the phase correction angle to a first phase correction angle, thereby machining the first tooth side surface by the gear cutting tool and by the gear skiving process. The crossing angle is made equal to the predetermined crossing angle, and the phase correction angle is set to a second phase correction angle different from the first phase correction angle, so that the second tooth side surface is machined by the gear skiving process using the same gear cutting tool as the gear cutting tool used to machine the first tooth side surface, The crossing angle is made equal to the prescribed crossing angle, and the phase correction angle is set to a reference phase correction angle different from the first phase correction angle and the second phase correction angle, so that a reference tooth groove having the reference angle is machined by the gear skiving process using the same gear cutting tool as the gear cutting tool used to machine the first tooth side surface, The processing of the first tooth side surface and the processing of the second tooth side surface are performed after the processing of the reference tooth groove. The tool blade of the gear cutting tool has a plurality of blades on the periphery. When the maximum tooth groove width of the tooth groove is smaller than twice the blade width of the tool blade, the tooth groove is formed by machining only the first tooth side surface and the second tooth side surface.

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