JP2019119016A - Gear processor and gear processing method - Google Patents

Abstract

To provide a gear processor which can alleviate a cutting load applied on a tool, and a gear processing method.SOLUTION: A gear processor performs cutting processing while feeding a gear-cutting tool to a rotation axial line direction of a workpiece W while synchronously rotating the gear-cutting tool and the workpiece W in a state that a rotation axial line of the gear-cutting tool is inclined to a parallel line of the rotation axial line of the workpiece W, and creates a gear at the workpiece W by performing feed motions a plurality of times when a cutting margin S is not uniform in the rotation axial line direction of the workpiece W. The gear processor comprises a storage device in which a processing route program including a plurality of processing routes corresponding to a plurality of the feed motions, respectively, is stored. The processing route program includes a final processing route corresponding to the finally-performed feed motion, and following a shape of the gear which is created at the workpiece W, and an initial-stage processing route corresponding to the initially-performed feed motion, and not being a parallel line nor a parallel curved line with respect to the final processing route.SELECTED DRAWING: Figure 7B

Description

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

  In Patent Document 1, the processing tool is applied to the workpiece while twisting the central axis of the processing tool and the central axis of the workpiece to synchronize the rotation of the workpiece and the rotation of the processing tool. A technique is disclosed for generating gears on a workpiece with a plurality of protruding tool edges provided on the outer periphery of a processing tool by feeding in the direction of the central axis of the workpiece.

Unexamined-Japanese-Patent No. 2017-19034

  For example, in the case of forming a gear having a portion whose tooth height changes in the axial direction with respect to a cylindrical material, a cutting allowance to be cut by gear machining changes in the axial direction. When processing such a gear according to the shape of the gear when processing this gear according to the technology of Patent Document 1 mentioned above, the cutting load when cutting the portion where the cutting allowance becomes large becomes large if the processing tool is fed , Tools for processing become easy to break early.

  An object of the present invention is to provide a gear machining device and a gear machining method capable of reducing a cutting load applied to a tool.

  The gear machining device according to the present invention rotates the workpiece while synchronously rotating the gear cutting tool and the work in a state where the rotation axis of the gear cutting tool is inclined with respect to a parallel line of the rotation axis of the workpiece. The cutting is performed while feeding the gear cutting tool in the axial direction, and when the machining allowance is not uniform in the rotational axis direction of the workpiece, a gear is generated on the workpiece by performing a plurality of feeding operations. The gear machining device includes a storage device storing a machining path program including a plurality of machining paths corresponding to each of the plurality of feed operations. The machining path program corresponds to a final machining path which is a machining path corresponding to the feed operation to be performed last and which becomes a machining path conforming to the shape of a gear generated on the workpiece, and the feed operation to be performed first And a first processing path which is a processing path which is not a parallel line or a parallel curve with respect to the final processing path.

  According to the gear machining method of the present invention, the rotation of the gear cutting tool and the workpiece is synchronously rotated while the rotation axis of the gear cutting tool is inclined with respect to the parallel line of the rotation axis of the workpiece. The cutting is performed while feeding the gear cutting tool in the axial direction, and when the machining allowance is not uniform in the rotational axis direction of the workpiece, a gear is generated on the workpiece by performing a plurality of feeding operations. In the machining method, a final machining path, which is a machining path corresponding to the last feed operation among the plurality of feed operations, conforms to the shape of a gear generated on the workpiece, and corresponds to each of the plurality of feed operations. Of the plurality of processing paths, an initial processing path which is a processing path corresponding to an initial feeding operation does not become a parallel line or a parallel curve with respect to the final processing path.

  The gear machining device and the gear machining method of the present invention reduce the maximum cutting load applied to the gear cutting tool as compared with the case where all machining paths are shaped according to the shape of the gear formed on the workpiece. it can. As a result, the gear machining device and the gear machining method can improve the tool life of the gear cutting tool.

It is a perspective view of the gear processing apparatus in one embodiment of the present invention. It is a block diagram of a control device. It is the perspective view which expanded a part of external gear formed in a workpiece. It is sectional drawing in the IV-IV line of FIG. 5A and 5B, and shows the cross section of the workpiece containing a rotation axis and a tooth base. It is sectional drawing of the workpiece in the VA-VA line | wire of FIG. 4, and is the figure which expanded the axial direction cross section of the external tooth including the 1st site | part among workpieces partially expanded. It is sectional drawing of the workpiece in the VB-VB line | wire of FIG. 4, and is the figure which partially expanded the axial direction cross section of the external tooth which contains a 2nd site | part among workpieces. It is a flow chart of gear processing processing performed by a control device. It is the figure which represented typically the cross section of the cutting allowance at the time of cutting a 1st site | part and a 2nd site | part. It is the figure which added the first processing path, the middle processing path, and the last processing path to the section of the work including the axis of rotation and the tooth base. It is a graph which shows the relationship between a cutting part and the cutting load added to the gear cutting tool at the time of cutting. It is the figure which represented typically the cross section of the cutting allowance at the time of cutting a 1st site | part and a 2nd site | part in a 1st modification. It is the figure which added the first processing path, the middle processing path, and the last processing path to the section of the work including the axis of rotation and the tooth base. It is a graph which shows the relationship between a cutting part and the cutting load added to the gear cutting tool at the time of cutting. In the 2nd modification, it is the figure which represented typically the section of the cutting allowance at the time of cutting the 1st part and the 2nd part. It is the figure which added the first processing path, the middle processing path, and the last processing path to the section of the work including the axis of rotation and the tooth base. It is a graph which shows the relationship between a cutting part and the cutting load added to the gear cutting tool at the time of cutting. It is a graph which shows the relationship between the cutting part in a 3rd modification, and the cutting load added to the gear cutting tool at the time of cutting. It is the figure which added the first processing path, the middle processing path, and the last processing path to the section of the work including the axis of rotation and the tooth base.

  Hereinafter, an embodiment to which a gear machining device and a gear machining method according to the present invention are applied will be described with reference to the drawings. First, with reference to FIG. 1 and FIG. 2, the outline of the gear processing apparatus 1 which is one Embodiment of this invention is demonstrated.

(1. Outline of gear machining device 1)
As shown in FIG. 1, the gear machining device 1 is a machining center having three rectilinear axes (X axis, Y axis and Z axis) orthogonal to one another and two rotation axes (A axis and C axis) as drive axes. is there. The gear machining device 1 mainly includes a bed 10, a tool holding device 20, a workpiece holding device 30, and a control device 100. Bed 10 is placed on the floor. On the upper surface of the bed 10, a pair of X axis guide rails 11 extending in the X axis direction and a pair of Z axis guide rails 12 extending in the Z axis direction are provided.

  The tool holding device 20 includes a column 21, an X-axis drive 22, a saddle 23, a Y-axis drive 24, a tool spindle 25, and a tool spindle motor 26. In FIG. 1, the X-axis drive 22, the Y-axis drive 24, and the tool spindle motor 26 are not shown.

  The column 21 is provided to be movable in the X-axis direction while being guided by the pair of X-axis guide rails 11. The X-axis drive device 22 is a screw feeding device that feeds the column 21 in the X-axis direction with respect to the bed 10. Further, a pair of Y-axis guide rails 27 extending along the Y-axis direction is provided on the side surface of the column 21, and the saddle 23 is guided by the pair of Y-axis guide rails 27 with respect to the column 21. It is provided movably. The Y-axis drive unit 24 is a screw feeder which feeds the saddle 23 in the Y-axis direction.

  The tool spindle 25 is rotatably supported by the saddle 23 about an axis parallel to the Z-axis direction. At the tip of the tool spindle 25, a gear cutting tool 40 used for processing the workpiece W is detachably mounted. The gear cutting tool 40 is rotatably held about an axis parallel to the Z axis with respect to the tool holding device 20. The gear cutting tool 40 moves in the X axis direction with the movement of the column 21 and moves in the Y axis direction with the movement of the saddle 23. The tool spindle motor 26 is a motor that applies a driving force for rotating the tool spindle 25, and is housed inside the saddle 23.

  The workpiece holding device 30 includes a feed stand 31, a Z-axis drive device 32, a tilt device 33, and a workpiece rotation device 34. In addition, illustration of the Z-axis drive device 32 is abbreviate | omitted in FIG. The feed stand 31 is provided movably in the Z-axis direction while being guided by the pair of Z-axis guide rails 12 with respect to the bed 10. The Z-axis drive unit 32 is a screw feed unit that feeds the feed base 31 in the Z-axis direction.

  The tilt device 33 includes a pair of table support portions 35, a tilt table 36, and an A-axis motor 37. The pair of table support portions 35 is installed on the upper surface of the feed stand 31, and the tilt table 36 is supported by the pair of table support portions 35 so as to be pivotable about an A axis parallel to the X axis. The A-axis motor 37 is a motor for applying a driving force for swinging the tilt table 36 about the A-axis, and is accommodated inside the table support portion 35.

  The workpiece rotation device 34 includes a rotary table 38 and a C-axis motor 39. The rotary table 38 is rotatably installed around the C axis orthogonal to the A axis with respect to the bottom surface of the tilt table 36. The rotary table 38 is provided with a holding portion 38 a that fixes the workpiece W. The C-axis motor 39 is a motor that applies a driving force for rotating the rotary table 38, and is provided on the lower surface of the tilt table 36.

  The gear machining device 1 tilts the rotation axis of the gear cutting tool 40 with respect to the parallel line of the rotation axis of the workpiece W by swinging the tilt table 36 when performing gear machining. In this state, the gear machining device 1 performs cutting while feeding the gear cutting tool 40 in the rotational axis direction of the workpiece W while synchronously rotating the gear cutting tool 40 and the workpiece W.

  As shown in FIG. 2, the control device 100 includes a tool rotation control unit 110, a workpiece rotation control unit 120, a tilt control unit 130, a position control unit 140, and a storage device 150. The tool rotation control unit 110 controls the drive of the tool spindle motor 26 and rotates the gear cutting tool 40 mounted on the tool spindle 25. The workpiece rotation control unit 120 performs drive control of the C-axis motor 39 to rotate the workpiece W fixed to the rotary table 38 around the rotation axis (around the C axis). The tilt control unit 130 controls the drive of the A-axis motor 37 and swings the tilt table 36 to swing the workpiece W fixed to the rotary table 38 around the A-axis.

  The position control unit 140 performs drive control of the X-axis drive unit 22 to move the column 21 in the X-axis direction and drive control of the Y-axis drive unit 24 to move the saddle 23 in the Y-axis direction. As a result, the gear cutting tool 40 held by the tool holding device 20 moves relative to the workpiece W held by the workpiece holding device 30 in the X-axis direction and the Y-axis direction. Further, the position control unit 140 performs drive control of the Z-axis drive device 32 to move the feed stand 31 in the Z-axis direction. Thereby, the workpiece W held by the workpiece holding device 30 moves relative to the gear cutting tool 40 held by the tool holding device 20 in the Z-axis direction.

  The storage unit 150 stores a machining path program including machining path data when cutting is performed while being fed to the gear cutting tool 40 in the rotational axis direction of the workpiece. The details of the machining path data included in the machining path program will be described in detail later.

(2. Shape of gear formed on the workpiece W)
Here, with reference to FIGS. 3 to 5B, the shape of the gear formed on the workpiece W in the present embodiment will be described. As shown in FIG. 3 to FIG. 5B, the gear formed on the workpiece W is an external gear, and the tooth bottom surface is to one end at an end of the workpiece W in the rotation axis direction one end side (right side in FIG. 4) It is formed in a tapered shape in which the root diameter decreases as it goes.

  That is, as shown in FIGS. 4 to 5B, on the tooth base of the gear, a portion where the root diameter is constant in the tooth direction and a tapered portion where the root diameter changes in the tooth direction Is formed. On the other hand, the tip diameter of the gear is constant in the entire tooth direction. Therefore, the gear formed on the workpiece W has a first portion w1 in which the root diameter and the height H1 are constant in the tooth direction, and a second portion in which the root diameter and the height H2 change in the tooth direction. And a part w2.

  In machining such a gear, if the workpiece W as a material before gear machining has a cylindrical shape, the machining allowance S of the portion forming the second portion w2 is the portion forming the first portion w1 It becomes larger than the cutting allowance S of. Therefore, the cutting load applied to the gear cutting tool 40 when cutting the second portion w2 is larger than the cutting load applied to the gear cutting tool 40 when cutting the first portion w1.

  In this regard, the gear machining device 1 performs the feeding operation of sending the gear cutting tool 40 from the one end side to the other end side (the right side to the left side in FIG. 4) of the workpiece W in the axial direction. Specifically, the gear machining device 1 performs a plurality of cutting processes including at least one roughing process for roughing the workpiece W and a finishing process for finishing the workpiece W after the roughing. By performing the provided gear machining process, a gear having a desired shape is created on the workpiece W.

  The machining path program stored in the storage device 150 includes a plurality of machining path data corresponding to each of a plurality of feed operations performed in the gear machining process. Each machining path data included in the machining path program is a machining allowance S to be scraped off by the gear cutting tool 40 in a plurality of cutting processes executed in the gear machining process, and the number of cutting processes to be executed in the gear machining process ( And the number of feeding operations). The gear machining device 1 can reduce the maximum cutting load applied to the gear cutting tool 40 by performing cutting based on the machining path program in each cutting process performed in the gear machining process. In the following, the machining path in each cutting process performed in the gear machining process will be described by giving a specific example.

(3. Gear processing)
Next, an example of the gear machining process will be described with reference to the flowchart shown in FIG. The gear machining process is performed by the control device 100 at the time of gear machining. In the gear machining process, the feed operation is performed three times to create the external gear shown in FIG. 3 to FIG. 5B on the workpiece W. The gear machining process is a first roughing process of roughing a workpiece W as a cylindrical material as a first cutting process, and a process after the first roughing process as a second cutting process. A second roughing process for performing a second roughing process on the object W and a finishing process for performing a finishing process on the workpiece W after the roughing process are provided as a third cutting process.

  As shown in FIG. 6, in the gear machining process, first, approach feeding is performed to place the gear cutting tool 40 at the feeding operation start position (S1). After the process of S1, the gear machining process executes a first roughing process (S2). After the processing of S2, the gear machining process performs the rapid feed of the gear cutting tool 40, and the gear cutting tool 40 which has reached the other end side in the rotational axis direction of the workpiece W by the feed operation in the first roughing process The feed operation start position of one end side in the direction of the rotational axis of W is returned (S3).

  After the process of S3, the gear machining process executes a second roughing process (S4). After the process of S4, in the gear machining process, as in the process of S2, the gear cutting tool 40 is fast-forwarded to return the gear cutting tool 40 to the feed operation start position (S5). After the process of S5, in the gear machining process, a finishing process is performed (S6), and the process is ended.

(4. Specific example of processing route)
Subsequently, with reference to FIG. 7A to FIG. 7C, each machining path in the three cutting processes performed in the gear machining process will be described by giving a specific example. In the following, the processing path in the first roughing process is referred to as "first processing path", the processing path in the second roughing process as "intermediate processing path", and the processing path in the finishing process as "final processing path" .

  On the left side of FIG. 7A, a diagram schematically showing a cross section of a cutting allowance for cutting off the first portion w1 by the cutting tool 40 in three cutting processes is shown, and on the right side of FIG. 7A, three times The figure which represented typically the cross section of the cutting allowance which the gear cutting tool 40 cuts away the 2nd site | part w2 in the cutting process of is shown. Among the machining allowances for the first portion w1, the cross-sectional area of the machining allowance to be scraped off in the first roughing process is "cutting cross-sectional area s11", and the sectional area of the shaving allowance to be scraped off in the second roughing process is "cutting cross-sectional area s21 The cross-sectional area of the machining allowance to be scraped off in the finishing process is referred to as “cutting cross-sectional area s31”. Similarly, among the machining allowances of the second part w2, the cross-sectional area of the machining allowance to be scraped off in the first roughing process is "cutting cross-sectional area s12", and the cross-sectional area of the shaving allowance to scrape off in the second roughing process is "cutting cross-sectional area s22 '', a cross-sectional area of a cutting allowance to be removed in the finishing process is referred to as "cutting cross-sectional area s32".

  FIG. 7B shows a first machining path at a portion scraped off as a machining allowance S in the sectional view of the workpiece W after gear machining shown in FIG. 4 (a sectional view including the rotation axis and the tooth bottom of the workpiece W), The intermediate processing path and the final processing path are illustrated. In each of the initial processing path, the intermediate processing path, and the final processing path, the processing path when processing the first portion w1 is referred to as “first path P11, P21, P31” and the second portion w2 is processed The processing path at the time of making is referred to as "second path P12, P22, P32", respectively. Moreover, in FIG. 7B, the path of the gear cutting tool 40 when executing the fast feed in the processes of S2 and S4 of the gear machining process is illustrated by a dotted line.

  As shown in FIG. 7A, the three machining paths included in the machining path program are set so as to have a cutting cross-sectional area of a cutting allowance S to be scraped off by each of the three cutting steps. That is, the first paths P11, P21, and P31 are set so that the cutting cross-sectional areas s11, s21, and s31 become uniform, and the second paths P12, P22, and P32 have the cutting cross-sectional areas s21, s22, and s32 are uniform. Is set to be

  In this case, as shown in FIG. 7B, in the first portion w1, the first paths P11, P21, and P31 of the first machining path, the intermediate machining path, and the final machining path are straight lines that follow the rotation axis of the workpiece W. It becomes a state. On the other hand, in the second portion w2, the second path P32 of the final machining path is a shape conforming to the shape of the gear (the shape of the tooth bottom) formed on the workpiece W, while the second path P22 of the intermediate machining path Takes a position away from the final processing path as compared to the first path P21. Similarly, the second path P12 of the first processing path takes a position away from the intermediate processing path as compared to the first path P11. As described above, in any of the three cutting processes, the amount of cutting when cutting the second portion w2 is larger than the amount of cutting when cutting the first portion w1.

  As a result, as shown in FIG. 7C, in each of the first roughing process, the second roughing process, and the finishing process, the cutting load applied to the gear cutting tool 40 at the time of processing the second portion w2 is the first portion w1. The cutting load applied to the hob 40 at the time of machining of

  Here, in the finishing process, which is the final cutting process among the three cutting processes, it is necessary to perform cutting so that the shape of the gear formed on the workpiece W becomes the final desired shape. Because of this, the final machining path is shaped according to the final shape of the gear formed on the workpiece W. In this regard, if cutting is performed in the first roughing process and the second processing process along the processing path according to the shape of the gear formed on the workpiece W, the second portion w2 in the first roughing process is processed The maximum cutting load generated on the hobbing tool 40 sometimes increases.

  That is, when the three machining paths are shaped according to the shape of the gear formed on the workpiece W, all the machining paths become parallel. In this case, in the second roughing process and the finishing process, the cutting amount when cutting the second portion w2 is equal to the cutting amount when cutting the first portion w1. Therefore, an increase in the cutting allowance of the second portion w2 which increases as compared with the first portion w1 is cut at a time in the first roughing process. As a result, in the first roughing process, the maximum cutting load when cutting the second portion w2 is increased.

  On the other hand, the three processing paths included in the processing path program are set such that the initial processing path and the intermediate processing path do not become parallel lines or parallel curves with respect to the final processing path. That is, in the present embodiment, the first processing path and the second paths P12 and P22 of the intermediate processing path are set so as not to be parallel lines or parallel curves with respect to the second path P32 of the final processing path. Thereby, the gear machining device 1 can suppress the maximum cutting load applied to the gear cutting tool 40 as compared with the case where all machining paths are shaped according to the shape of the gear formed on the workpiece W. .

  Further, in the present embodiment, the gear machining device 1 processes the second portion w2 which needs to scrape the workpiece W more than the first portion w1. The cut amount is made larger than the cut amount of the first portion w1. Thereby, the gear machining device 1 can avoid that the maximum cutting load applied to the gear cutting tool 40 in the specific cutting process becomes high among the cutting processes performed multiple times.

  In addition to this, in the present embodiment, the first processing path and the second paths P12 and P22 of the intermediate processing path are set so that the cutting cross-sectional areas s12, s22 and s32 become uniform. Thereby, the gear machining device 1 can reduce the maximum cutting load applied to the gear cutting tool 40 in each of the three cutting processes.

  As shown in FIG. 7B, in the case of setting the processing path three times so that the cross-sectional area becomes uniform in the three cutting steps, the finishing step includes the first roughing step and the second roughing step. As compared with the processing step, the cutting load generated at the time of processing the first portion w1 becomes smaller, and the cutting load generated at the time of processing the second portion w2 becomes smaller. As a result, the gear machining device 1 can perform gear machining with high accuracy in the finishing process. Further, since the machining path data included in the machining path program is set based on the cutting cross-sectional area, the machining path can be easily set.

(5. Modification of machining path)
Next, with reference to FIG. 8A to FIG. 10B, a modification of the processing path included in the processing path program will be described by giving a specific example. In addition, the same code | symbol is attached | subjected to the structure same as the said embodiment, and the description is abbreviate | omitted. Also, in any of the following modified examples, the feeding operation is performed three times. 8A and 9A correspond to FIG. 7A. Similarly, FIGS. 8B, 9B and 10B correspond to FIG. 7B, and FIGS. 8C, 9C and 10A correspond to FIG. 7C.

(5-1: First Modification)
First, the first modification will be described with reference to FIGS. 8A to 8C. As shown to FIG. 8A and FIG. 8B, the intermediate | middle process path | route of a 1st modification is set as the shape which followed the shape of the gearwheel formed in the workpiece W. As shown in FIG. On the other hand, the initial machining path of the first modification is set such that the cutting cross-sectional area s12 in the first roughing process and the cutting cross-sectional area s22 in the second roughing process become uniform when processing the second portion w2. Be done. In the first modification, the first paths P11, P21, and P31 are set in the same manner as the above embodiment.

  In this case, the intermediate processing path is parallel to the final processing path. In this case, the cutting amount when cutting the second portion w2 in the final processing step is equal to the cutting amount when cutting the first portion w1. On the other hand, the second path P12 of the first processing path takes a position away from the intermediate processing path as compared with the first path P11. Therefore, in the first roughing process and the second processing process, the cutting amount when cutting the second portion w2 is larger than the cutting amount when cutting the first portion w1.

  As a result, as shown in FIG. 8C, in the finishing process, compared with the first roughing process and the second roughing process, the gear cutting tool at the time of processing the first portion w1 and the time of processing the second portion w2 The difference in cutting load generated at 40 is reduced. As described above, the first modification can reduce the maximum cutting load applied to the hobbing tool 40 in the finishing process, as compared with the above embodiment. Thereby, the first modification can improve the accuracy of the gear formed on the workpiece W.

  On the other hand, in the first modification, in the first roughing process and the second roughing process, the incised amount of the second portion w2 is made larger than the incised amount of the first portion w1. In this case, the gear machining device 1 can suppress the maximum cutting load applied to the gear cutting tool 40 in the first roughing process and the second roughing process. As described above, in the machining path program of the first modified example, a plurality of machining paths such that the cutting amount when processing the second portion w2 is larger than the cutting amount when cutting the first portion w1 Therefore, the gear machining device 1 can reduce the maximum cutting load applied to the gear cutting tool 40.

  In the first modification, the cutting cross-sectional area s31 of the first portion w1 in the finishing process is greater than the cutting cross-sectional areas s11 and s21 of the first portion w1 in the first roughing step and the second roughing step. Three processing paths may be set to be smaller. In this case, since the first modification can further reduce the maximum cutting load generated on the gear cutting tool 40 in the finishing process, the accuracy of the gear formed on the workpiece W can be further improved. .

(5-2: Second Modified Example)
Next, a second modification will be described with reference to FIGS. 9A to 9C. As shown in FIGS. 9A and 9B, the first machining path and the intermediate machining path of the second modification are in a straight line in which the first paths P11 and P21 and the second paths P12 and P22 are parallel to the machining axis of the workpiece. Is set as In the second modification, the first paths P11, P21, and P31 are set in the same manner as the above embodiment. In this case, the amount of cutting when cutting the second portion w2 in the final processing step is larger than the amount of cutting when cutting the second portion w2 in the first roughing step and the second roughing step.

  However, as shown in FIG. 9C, the cutting load L3 applied to the hobbing tool 40 in the finishing process at the first portion w1 is the cutting load applied to the hobbing tool 40 in the first roughing process and the second roughing process. It is smaller than L1 and L2. In this respect, in the second modification, in comparison with the maximum cutting load applied to the gear cutting tool 40 in the first cutting process when forming all machining paths into a shape conforming to the shape of the gear formed on the workpiece W The maximum cutting load applied to the gear cutting tool 40 can be suppressed.

  In the second modification, the cutting cross-sectional area s31 of the first portion w1 in the finishing process is greater than the cutting cross-sectional areas s11 and s21 of the first portion w1 in the first roughing step and the second roughing step. Three processing paths may be set to be smaller. In this case, the second modification can suppress the maximum cutting load applied to the gear cutting tool 40 in the finishing process. Also, for example, in applications of the gear formed on the workpiece W, high accuracy may be required at the first portion w1, but accuracy as high as the first portion w1 may not be required at the second portion w2. In this case, the second modification can create a gear according to the requirements of each use application by enhancing the accuracy of the gear formed at the first portion w1.

(5-3: Third Modified Example)
Next, a third modified example will be described with reference to FIGS. 10A and 10B. In the above embodiment, the three processing paths are set so that the cutting cross-sectional area becomes uniform in three cutting steps, while the third modification example is three times as shown in FIGS. 10A and 10B. Three processing paths are set so that the cutting load is uniform in the cutting process of Thereby, the third modified example can achieve the same effect as the above embodiment in which the machining path is set based on the cutting cross-sectional area, and can suppress the maximum cutting load applied to the gear cutting tool 40.

  The third modification can also be applied to the first modification described above. That is, in the first modification example described above, the first processing path is performed so that the cutting load L1 in the first roughing process and the cutting load L2 in the second roughing process become uniform at the time of processing the second portion w2. And an intermediate processing path may be set. The third modification in this case has the same effect as the first modification in which the machining path is set based on the cutting cross-sectional area, and can suppress the maximum cutting load applied to the gear cutting tool 40.

(6. Other)
As mentioned above, although the present invention was explained based on the above-mentioned embodiment and each modification, the present invention is not limited at all to the above-mentioned embodiment and each modification, and various modification within the range which does not deviate from the meaning of the present invention It is easy to guess that improvements are possible.

  For example, in the above embodiment and each modification, as an example of the gear formed on the workpiece W, the present invention is applied to an external gear including a second portion in which the tooth bottom is formed in a tapered shape. Although described, the present invention can be applied when forming a gear whose cutting allowance is not uniform in the rotational axis direction of the workpiece. That is, the present invention is also applicable to a gear forming a gear having a portion where the tooth height changes in the axial direction, for example, a gear whose tip surface is deformed in the axial direction, a gear whose second portion is a curved surface, etc. be able to. Furthermore, the present invention can be applied not only to the external gear but also to the internal gear.

  In the above embodiment and each modification, the case where the feeding operation is performed three times has been described as an example, but the feeding operation may be performed twice or four times or more. Similarly, in the gear machining process, the rough machining process may be performed only once and the intermediate machining process may be omitted, or the intermediate machining process may be performed multiple times for three or more rough machining processes.

  Although in the above embodiment, the three processing paths are set so that the cutting cross-sectional area becomes uniform in three cutting steps, the present invention is not limited to the case where the cutting cross-sectional area is uniform . That is, the cutting load at the time of processing the second portion w2 in each of all the cutting steps is the first portion w1 while all the processing paths do not become parallel lines or parallel curves in at least the second path. It may be set to be larger than the cutting load when machining. Thus, the gear machining device 1 can reduce the maximum cutting load applied to the gear cutting tool 40.

  Furthermore, in this case, all the processing paths may be set such that the cutting cross-sectional area or the maximum cutting load at the time of processing the second portion w2 is the smallest among all the processing paths. . Thus, the gear machining device 1 can reduce the maximum cutting load generated on the gear cutting tool 40 in the finishing process.

  Here, when performing gear skiving processing using the gear processing apparatus 1, viewed from a direction orthogonal to a plane including the processing point at which the gear cutting tool 40 contacts the workpiece W and the rotation axis of the workpiece W The axis of rotation of the hob 40 and the axis of rotation of the workpiece W are neither perpendicular nor parallel to one another. That is, in the gear skiving process, the rotational axis of the gear cutting tool 40 and the rotational axis of the workpiece W are disposed in a twisted state, and the gear cutting is efficiently performed by rotating at high speed while synchronizing the gear cutting tool 40 with the workpiece W. It is possible to perform high gear machining.

  On the other hand, when the amount of infeed and the amount of feed during machining are increased, the time required for gear machining is shortened, while the cutting load applied to the gear cutting tool 40 is increased. In particular, in gear skiving processing, while gear processing is performed while continuously changing the rake angle, processing is performed with the rake angle greatly changing in the negative direction as the cutting amount and feed amount increase. The time to be performed becomes long, and the cutting load applied to the hob 40 increases. That is, increasing the infeed amount and the infeed amount causes the wear, breakage, and the like of the gear cutting tool 40 to occur at an early stage. In this regard, by reducing the cutting load, the gear machining device 1 can reduce the wear, breakage, and the like of the gear cutting tool 40 while shortening the time required for gear machining.

  1: Gear processing device, 150: Storage device, H1, H2: Tooth length, L1, L2, L3: Cutting load, P11, P21, P31: First path, P12, P22, P32: Second path, S: Shaping S11, s12, s21, s22, s31, s32: cutting cross section, W: workpiece, w1: first part, w2: second part

Claims (13)

In a state in which the rotational axis of the gear cutting tool is inclined with respect to the parallel line of the rotational axis of the workpiece, the gear cutting tool is rotated in the rotational axis direction of the workpiece while synchronously rotating the gear cutting tool and the workpiece. A gear machining device for generating gears on a work by performing a plurality of feeding operations when cutting is performed while being fed and a machining allowance is not uniform in the direction of the rotation axis of the work.
The gear machining device includes a storage device storing a machining path program including a plurality of machining paths corresponding to each of the plurality of feed operations,
The machining path program corresponds to a final machining path which is a machining path corresponding to the feed operation to be performed last and which becomes a machining path conforming to the shape of a gear generated on the workpiece, and the feed operation to be performed first And a first machining path which is a machining path which is not a parallel line or a parallel curve with respect to the final machining path. Each of the plurality of processing paths is
A first path which is a processing path when processing a first portion of the workpiece in which the cutting allowance does not change in the rotational axis direction of the workpiece;
A second path which is a processing path when processing a second portion of the workpiece in which the cutting allowance changes in the rotational axis direction of the workpiece;
Including
The gear machining device according to claim 1, wherein the second path of the first machining path does not form a parallel line or a parallel curve with respect to the second path of the final machining path.   The gear machining according to claim 2, wherein the machining path program includes a plurality of machining paths in which a cutting amount when machining the second portion is larger than a cutting amount when machining the first portion. apparatus.   The gear according to claim 3, wherein all the machining paths included in the machining path program have a cutting amount when machining the second portion is larger than a cutting amount when machining the first portion. Processing equipment.   The gear machining device according to claim 4, wherein all machining paths included in the machining path program have a uniform cutting cross-sectional area when machining the second portion.   The gear machining device according to claim 3, wherein the final machining path has the smallest cutting cross-sectional area at the time of machining the second portion among all the machining paths included in the machining path program.   The gear machining device according to claim 2, wherein the machining path program includes a plurality of machining paths in which a cutting load at the time of machining the second portion is larger than a cutting load at the time of machining the first portion.   The gear machining device according to claim 7, wherein all machining paths included in the machining path program have a cutting load at the time of machining the second portion larger than that at the time of machining the first portion. .   The gear machining device according to claim 8, wherein all machining paths included in the machining path program have a uniform cutting load when machining the second portion.   The gear machining device according to claim 7 or 8, wherein the final machining path has the smallest cutting load when machining the second portion among all the machining paths included in the machining path program.   The machining path other than the final machining path among the plurality of machining paths included in the machining path program is a straight line in which the first path and the second path are parallel to the rotation axis of the workpiece. The gear processing apparatus as described in 2.   The gear machining according to any one of claims 1 to 11, wherein the gear machining device creates a gear having a portion where the tooth height changes in the direction of the teeth with respect to the cylindrically formed workpiece. apparatus. In a state in which the rotational axis of the gear cutting tool is inclined with respect to the parallel line of the rotational axis of the workpiece, the gear cutting tool is rotated in the rotational axis direction of the workpiece while synchronously rotating the gear cutting tool and the workpiece. A gear machining method for generating a gear on the work by performing a plurality of feeding operations when cutting is performed while being fed and a cutting allowance is not uniform in the rotational axis direction of the work.
The final machining path, which is the machining path corresponding to the last feeding operation among the plurality of feeding operations, follows the shape of a gear generated on the workpiece;
Of a plurality of machining paths corresponding to each of the plurality of feed operations, an initial machining path serving as a machining path corresponding to the first feed operation does not form a parallel line or parallel curve with respect to the final machining path Processing method.

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