JP6471504B2 - Crown gear manufacturing equipment - Google Patents

Description

The present invention relates to apparatus for manufacturing a crown gear with cut data used for skiving.

Conventionally, as a publicly known document relating to a crown gear manufacturing apparatus, there is an apparatus disclosed in Japanese Patent Application Laid-Open No. 2014-004650.
It is described that this apparatus can efficiently produce a crown gear by using a general-purpose machining center or the like without using a gear cutting apparatus using an annular cutter so far by using skiving processing technology.

JP 2014-004650 A

  In the conventional crown gear manufacturing apparatus, when a crown gear that meshes with a pinion having a small number of teeth is manufactured, the cutter is thin and the rigidity is low. Therefore, the cutter may vibrate when attempting to process at high speed. As a result, inconveniences such as deterioration of the surface roughness of the tooth surface formed on the workpiece and reduction of the cutter life have occurred.

  Also, when machining, the cutter is machined while maintaining a predetermined tilt angle with respect to the workpiece surface. The relative position of this workpiece and the cutter is relative to the gears when the finished workpiece is used. Different from position. Therefore, if the same tooth profile as the counterpart gear meshing with the crown gear in use is applied to the cutter, the tooth profile of the processed crown gear will be different from the intended tooth profile.

Furthermore, when the cutter processes the outer edge of the gear cutting part of the workpiece and when processing the inner edge, the cutting amount and the machining component acting on the cutter differ. Life is shortened.
In addition, there is a point to be improved in the above-described conventional manufacturing apparatus such that a large burr is generated when a single cutting process is completed and the cutter comes out of the workpiece.

Accordingly, an object of the present invention is to provide an apparatus for manufacturing a crown gear with cut data for skiving to increase productivity without sacrificing machining accuracy and cutter life in machining of the crown gear.

The characteristic configuration of the crown gear manufacturing apparatus according to the present invention is as follows:
Cutting the formed first edge, and the cutting blade forming portions also comprising a screw-like portion of at least Ichijo having the same sectional shape as the cutting edge at any position along the direction of the rotational axis,
A gripping part fixed to the rotating shaft of the machine tool and formed in a columnar shape and having an outer diameter larger than the outer diameter of the cutting blade forming part;
Provided with a cutter provided between the cutting blade forming portion and the gripping portion and having an intermediate portion whose cross-sectional shape expands from the cutting blade forming portion toward the gripping portion ;
A workpiece support that supports the workpiece rotatably around the first axis;
A cutter support portion having an inclination angle with respect to a virtual plane orthogonal to the first axis, and supporting the cutter rotatably around the second axis;
Set the cutting angle of the cutter with respect to the tilt angle and the workpiece,
When viewed along the direction of the first axis, the movement trajectory of the cutter is set in a state offset to the upper side in the rotation direction of the workpiece so as not to intersect the first axis;
A cutting control unit that moves the cutter on a virtual plane perpendicular to the first axis while rotating the workpiece and the cutter synchronously .

As in this configuration, in the crown gear manufacturing apparatus, the cutter is provided with a grip portion having a diameter larger than that of the cutting edge forming portion, and is an intermediate portion that expands from the cutting edge forming portion on the distal end side toward the gripping portion on the proximal end side. By providing the portion, the bending rigidity of the cutter continuously changes in the region between the cutting edge forming portion and the gripping portion, and in particular, the bending strength of the cutter can be increased.
The cutter is used for skiving processing in which the cutter and workpiece are rotated synchronously while feeding the cutter in the tooth gap direction, but the cutting edge formed at the tip of the tool does not escape from the workpiece during machining. The feed operation is performed with the cutting blade pressed against the workpiece. Therefore, by providing the intermediate portion as in this configuration and increasing the bending strength of the cutter, the bending of the cutter during cutting is reduced, and more precise machining is possible.

Also, with this configuration, skiving is performed using a cutter having the above-described intermediate portion and improved bending strength. Therefore, vibration of the cutter during processing is prevented, and an accurate crown gear is efficiently used. Can be manufactured.

The crown gear manufacturing apparatus according to the present invention is characterized in that the cutting movement is repeated a plurality of times, and the cutting control unit performs cutting after a predetermined number of times has elapsed from an inclination angle of the cutter in a cutting movement less than a predetermined number of times It lies in to set smaller the inclination angle of movement.

  By changing the inclination angle of the rotation axis of the cutter, the cutting width in one cutting can be changed. By increasing the inclination angle, the end surface of the cutting edge forming portion comes close to the cutting surface of the workpiece. Therefore, if the cutting depth in one cutting is the same, the crossing area between the end face of the cutting edge forming part and the cutting surface of the workpiece becomes wider when the rotation axis of the cutting edge is laid down, and the area of the cutting area Spread. In other words, the crown gear forms a tooth profile by gradually digging the processed surface, but the width of the tooth gap is naturally wider on the tooth tip side. Therefore, when the cutting movement is less than the predetermined number of times as in this configuration, a wide range of cutting is performed by increasing the inclination angle of the cutting edge and laying down the cutting edge. Narrow cutting is possible by laying down. With this configuration, the production efficiency of crown gears by skiving is greatly improved.

In the crown gear manufacturing apparatus according to the present invention, the cutting movement is repeated a plurality of times, and the cutting control unit sets the offset amount in the subsequent cutting movement to the offset amount in the previous cutting movement. It can also be set small.

  In skiving processing, “slip” between the workpiece and the cutter, which is caused by an angle difference between the direction in which the cutting position of the workpiece moves and the direction in which the cutter rotates, is used. For example, it is assumed that the cutter feed direction is offset toward the upper side of the workpiece rotation direction without crossing the first axis when viewed along the first axis. The shortest distance between the extension line in the feed direction of the cutter and the first axis is hereinafter referred to as an offset amount.

  The instantaneous movement direction of the cutting point on the workpiece is a tangential direction at the cutting point of a circle passing through the cutting point with the first axis as the center. On the other hand, the instantaneous movement direction of the cutting point on the cutting edge is a direction orthogonal to the second axis because the cutter rotates around the second axis and the feed rate exists in the cutter. The direction is slightly inclined to the cutter feed direction. That is, the smaller the offset amount, the closer the moving direction of the cutting point on the workpiece and the moving direction of the cutting point on the cutting edge, and the less the cutter slips. Conversely, the greater the offset amount, the wider the angle between the moving directions of both cutting points, and the greater the cutter slip.

  The offset amount of the cutter can be arbitrarily set, and thereby the cutting efficiency and cutting finish accuracy of the workpiece can be determined. For example, if the amount of offset is increased to increase the degree of sliding, the cutting efficiency is improved although it is roughing. On the other hand, if the degree of sliding is small, the cutting accuracy is reduced, but the finishing accuracy is improved.

  Therefore, as in this configuration, by setting the cutter offset amount in the subsequent cutting movement smaller than the cutter offset amount in the previous cutting movement, for example, the cutting efficiency of the workpiece is increased in the first half of the cutting process. In the second half of the cutting process, finishing accuracy can be increased. Therefore, with this configuration, a crown gear with good finishing accuracy can be obtained efficiently.

It is a perspective view which shows the external appearance of the crown gear manufacturing apparatus of this embodiment. It is a perspective view which shows the external appearance of the cutter of this embodiment. It is explanatory drawing which shows the change of the inclination-angle of a cutter. It is explanatory drawing which shows the mode of tooth gap formation by the difference in the inclination angle of a cutter. It is explanatory drawing which shows the movement path | route of the cutter of another embodiment. It is explanatory drawing which shows the change of the offset amount of the cutter of another embodiment. It is explanatory drawing which shows the attitude | position change mechanism of the cutter of another embodiment.

〔overall structure〕
An example of the crown gear manufacturing apparatus of the present invention is shown in FIG. The manufacturing apparatus includes a workpiece support unit 2 that rotatably supports a workpiece 1 to be machined about a first axial core X1 that is vertically oriented, and a second axial core X2 that is different from the first axial core X1. A cutter support portion 4 that rotatably supports 3, a moving portion 5 that moves the cutter support portion 4 relative to the workpiece support portion 2, and a cutting that synchronously rotates the workpiece support portion 2 and the cutter support portion 4 with a driving force. And a control unit 6.

  The crown gear is a general term for a crown gear in which teeth are formed on a surface in a posture perpendicular to the rotation axis. This crown gear includes a face gear, and includes a gear whose tooth trace direction is formed in a straight line and a helical gear whose tooth trace direction is inclined. In particular, the crown gear of the present embodiment is suitably used for a high reduction face gear with a reduction ratio of 3 or more. In the high speed reduction face gear, the mating gear on the other side is configured as a small gear or a worm gear. Of the crown gears, those in which the pinion gear or worm gear engages with a positional relationship that is inconsistent with the shaft core are referred to as crown gears, and those in which the pinion gear or worm gear engages in a positional relationship orthogonal to the axis are also referred to as face gears. However, as described above, the crown gear is a concept including a face gear, and the crown gear manufacturing apparatus of this embodiment can manufacture not only the crown gear but also the face gear.

  Further, in the crown gear manufacturing apparatus of the present embodiment, in addition to the crown gear (or crown gear), it is also possible to manufacture a face gear with two axes orthogonal to each other and a face gear with a so-called offset in which the two axes are different. In particular, the present invention is particularly effective in a face gear having a high speed reduction gear having a reduction ratio of 3 or more because it is necessary to reduce the number of teeth of the cutter 3.

  Regarding the arrangement of the cutter 3 with respect to the workpiece 1, the second axis X2 of the cutter 3 is parallel to a reference line L extending in the radial direction through the first axis X1 when viewed in the direction along the first axis X1, They are arranged in an offset area that is a set distance D away from the reference line L. The second axis X2 is on the plane of the virtual plane T parallel to the first axis X1 and the reference line L, and is inclined at an inclination angle θ with respect to the virtual plane S orthogonal to the first axis X1. doing. The moving unit 5 moves the cutter 3 linearly in parallel with the reference line L.

  The cutting control unit 6 sets the rotation speed of the cutter 3 in accordance with the rotation speed of the workpiece 1. In the present embodiment, the rotation direction of the cutter 3 is clockwise toward the distal end side of the cutter 3 as shown in FIG. The rotation direction of the work 1 is clockwise around the first axis X1 in a plan view of the work 1. As a result, the surface of the workpiece 1 moves obliquely relative to the second axis X2 of the cutter 3 in a plan view, and a “slip” occurs between the cutter 3 and the workpiece 1 so that the workpiece 1 is removed. Can be cut. Details of the “slip” will be described later.

  The workpiece support 2 is driven by the first motor M1 and has a plurality of chucks 21 that fix the workpiece 1. The cutter support unit 4 that moves along the moving unit 5 includes a holder 41 that holds the base end portion of the cutter 3, and a second motor M <b> 2 that rotationally drives the holder 41. The moving unit 5 includes a guide rail 51 that is parallel to the reference line L, a screw unit 52 that reciprocates the cutter support unit 4 along the guide rail 51, and a third motor M3 that drives the screw unit 52. I have.

  The first motor M1, the second motor M2, and the third motor M3 can synchronize their rotation speeds with a drive signal. The cutting control unit 6 stores a synchronization control unit 61 having a microprocessor, a DSP (Digital Signal Processing), etc., a means for acquiring the machining data so as to give the machining data to the synchronization control unit 61, and the machining data. And a machining data input unit 62 having a storage or the like.

  As another configuration, the crown gear manufacturing apparatus shown in FIG. 1 may be configured by, for example, a cutter support portion 4 provided at the tip of a manipulator.

[Cutter]
An example of the cutter 3 used in this embodiment is shown in FIG. On the distal end side of the cutter 3, there is provided a cutting edge 31 formed with a cutting edge 31 formed at the leading edge and at least one threaded portion having the same cross-sectional shape as the cutting edge 31. In this embodiment, it is formed in a double thread shape. On one base end side, there is provided a grip portion 33 formed in a columnar shape so as to be fixed to a holder 41 provided on a rotating shaft of a machine tool. The outer diameter of the grip part 33 is configured to be larger than the outer diameter of the cutting edge forming part 32. Between the cutting blade forming part 32 and the gripping part 33, there is provided an intermediate part 34 whose cross-sectional shape changes gradually from the cross-sectional shape of the cutting blade forming part 32 to the cross-sectional shape of the gripping part 33.

  In the intermediate portion 34, the tooth gap between the two cutting blades 31 is formed shallower toward the grip portion 33 in order to increase the bending rigidity of the cutter 3. By providing such an intermediate portion 34, for example, the bending strength or the like continuously changes from the end portion to the base end side of the cutting blade forming portion 32, and the mechanical strength of the cutter 3 is increased.

  Such a cutter 3 is used for skiving processing in which, for example, the cutter 3 and the workpiece 1 are rotated synchronously while the cutter 3 is fed to the workpiece 1 in the tooth gap direction. In machining, it is necessary to perform a feeding operation while pressing the cutting blade 31 against the workpiece 1 so that the cutting blade 31 at the tip of the tool does not escape from the workpiece 1. Therefore, by providing the intermediate part 34 as in the present configuration and increasing the bending strength of the cutter 3, vibrations of the cutter 3 during cutting are suppressed and the processing accuracy is improved.

  For example, the end face of the cutting edge forming portion 32 may be configured to be cut off so as to be a vertical face with respect to the second axis X2 of the cutter 3, or the edge cutting edge with respect to the center area of the end face. It is good also as a shape which inclined the 31 site | part to the front end side. In this case, even when the inclination angle θ of the cutter 3 is reduced, the cutting degree of the cutting edge 31 with respect to the processed surface of the workpiece 1 is increased. Further, the part of the cutting edge 31 may be retracted toward the base end side with respect to the center region of the cutter 3. In this case, the cutting depth of the cutting blade 31 is reduced, but the effect of extending the life of the cutting blade 31 can be obtained.

  The cutter 3 may be formed of tool steel, WC-Co based cemented carbide, or the like. Further, as shown in FIGS. 1 and 2, if a supply hole 35 for supplying lubricating oil is provided at the center of the cutter 3 along the first axis X1, resistance due to cutting is reduced, and generated during cutting. Since the heat is taken away, the characteristics of the workpiece 1 are hardly changed, and the cutter 3 is prevented from being damaged. It is also possible to discharge cutting waste generated by cutting. However, the cutter 3 can be configured without necessarily providing the supply hole 35.

  Crown gears are often used in combination with pinion gears. Therefore, it is preferable that the cutter 3 has the same shape as the pinion gear as much as possible. If the second axis X2 of the cutter 3 is arranged perpendicular to the first axis X1 of the workpiece 1 like a pinion gear, the cross-sectional shape of the cutting edge forming portion 32 is equal to the cross-sectional shape of the pinion gear. . On the other hand, when the second axis X2 of the cutter 3 is tilted with respect to the reference plane of the workpiece 1 until the end of the cutting process, the cross-sectional shape of the cutting edge forming portion 32 causes the cutter 3 to lie most. When cutting in a state, the desired tooth shape of the crown gear is obtained.

[Cutting mode]
In the present embodiment, processing is performed while changing the inclination angle θ of the cutter 3 in order to increase the cutting efficiency. Specifically, as shown in FIG. 3, for example, the cutting is divided into finishing cutting and previous cutting, and the inclination angle θ2 in the finishing cutting is set smaller than the inclination angle θ1 in the previous cutting such as the first time. The shape of the cutting edge 31 is set so that the tooth shape of the crown gear obtained by the finishing posture is the expected one.

  Thus, when the inclination angle θ of the cutter 3 is changed, the tooth groove shape formed on the workpiece 1 by cutting before finish cutting is different from the finished tooth groove shape. However, by setting the cutter 3 in a standing posture, as shown in FIG. 4, the cutting width becomes wider when the same cutting depth is cut as compared with the case where the cutter 3 is laid down. That is, by changing the inclination angle θ of the cutter 3, the cutting width and the cutting amount in one cutting can be changed.

  In FIG. 4, the left column indicates the state of cutting with the second axis X2 of the cutter 3 set up. Since the cutter 3 is viewed in parallel with the surface of the workpiece 1, the outer shape of the cutter 3 is elliptical. The cutter 3 rotates in the direction of the arrow from the upper first state to the lower third state, and the workpiece 1 moves to the left. As the cutter 3 rotates, the cutting blade 31 cuts the workpiece deeply. Of the three marks shown on the workpiece, the thickly displayed position is the center of the tooth bottom. The right column shows the state in which the cutter 3 is laid most in the finish cutting. The outer shape of the cutter 3 looks almost a perfect circle. These right columns also perform cutting at the same depth as the left column.

  The central view shows the amount of biting of the cutting blade 31 with respect to the workpiece 1 in the first state to the third state in the left and right rows. The left column with the cutter 3 standing up is a view when cutting the region close to the tooth tip of the tooth profile to be formed. The right row with the cutter 3 laid down is a view of a case where a region close to the tooth bottom is cut out of the formed tooth profile.

  As is clear from FIG. 4, when the cutter 3 is set up, the cutting start position of the cutter 3 is a position far from the center position of the tooth gap to be formed. Therefore, in the upper center figure, the cut width is slightly wider W1. On the other hand, in the finish cutting shown in the figure below, W2 is narrower than this. Thus, at the beginning of cutting, a wide range of cutting is performed by raising the second axis X2 of the cutter 3. In the subsequent finishing process or the like, the second axis X2 is laid, and the shape of the tooth gap is adjusted to the final finished shape although the cutting width is narrowed. As in this configuration, by changing the inclination angle θ of the cutter 3 according to the cutting process, the production efficiency of the crown gear by skiving is greatly improved.

  In the case of performing a plurality of passes, at least the finishing cutting pass lays the cutter 3 so as to be closest to the processing plane of the workpiece 1. In the cutting passes before that, the inclination angle θ of the cutter is set. May be set as appropriate. For example, all the passes before the finishing cutting pass may be inclined angles that are greater than the inclination angle of the finishing cutting pass, and the final pass including the finishing cutting pass is the same inclination angle θ as the finishing cutting pass, It is possible that the cutter is slightly inclined in the pass before that. These conditions are preferably set in consideration of the accuracy of the tooth mold to be formed, cutting efficiency, and the like.

[Another embodiment]
(1) In a general crown gear, for example, cylindrical side surfaces are formed on the outer peripheral edge portion and the inner peripheral edge portion of the tooth portion. During machining, the cutting edge 31 of the cutter 3 starts cutting by cutting into the workpiece 1 from, for example, the outer peripheral side surface, and the cutting for one time is completed by exiting from the inner peripheral side surface. At the time of withdrawal, burrs are generated at the edge of the work 1.

  When the cutting cut from the outer peripheral edge is repeated a plurality of times, burrs may grow on the inner peripheral edge from which the cutter 3 comes out. The burr that has grown to some extent is removed by any cutting pass. At that time, the already formed tooth gap is damaged, or the separated burr is sandwiched between the cutter 3 and the tooth groove, and the tooth is removed by the next cutting pass. The groove may be scratched.

  Therefore, as shown in FIG. 5, in the first cutting, the cutter 3 is moved from the outer peripheral edge portion toward the inner peripheral edge portion, and then the cutter 3 is cut into the inner peripheral edge portion and then cut out from the outer peripheral edge portion. To do. By doing so, burrs formed at the inner peripheral edge by the first cutting can be removed by cutting from the next inner peripheral edge, and the growth of burrs can be prevented. As a result, accurate tooth spaces can be stably formed without damaging the tooth spaces.

  As shown in FIG. 5, when the workpiece 1 is rotating in the clockwise direction, in the cutting in which the cutter 3 cuts from the outer peripheral edge portion, the rotation direction of the cutter 3 is clockwise toward the feeding direction. On the other hand, in the next cutting in which the cutter 3 cuts from the inner peripheral edge, first, the offset position of the cutter 3 is set in the advancing direction in order to maintain the engagement between the tooth groove of the cutter 3 and the tooth groove formed on the workpiece 1. Change from right to left. In addition, the rotation direction of the workpiece 1 is reversed while the rotation direction of the cutter 3 is maintained in the clockwise direction.

  In order to properly engage the cutter 3 and the workpiece 1 in this second cutting, the rotation direction of the cutter 3 may be changed without changing the rotation direction of the workpiece 1. However, in order to maintain the “slip (described later)” of the cutter 3 with respect to the workpiece 1, it is preferable to reverse the rotation direction of the workpiece 1. When these two cutting passes are completed and the cutter 3 comes out from the outer peripheral edge, the cutter 3 is returned to the original position, and cutting is performed by cutting again from the outer peripheral edge.

  In FIG. 6, an example of the processing apparatus using the slide of the workpiece | work 1 and the cutter 3 is shown. Slip occurs due to an angular difference between the moving direction of the workpiece 1 and the moving direction of the cutting edge 31. In this apparatus, the amount of slip is changed by changing the offset amount of the cutter 3. The feed direction of the cutter 3 is set along a straight line that does not intersect the first axis X1 when viewed in the direction along the first axis X1. That is, the cutter 3 is offset with respect to the diameter of the workpiece 1. Further, the offset direction is the upper side in the rotation direction of the workpiece 1.

  In the first half of the plurality of cutting movements, the offset amount of the cutter 3 is set to D1. When the offset amount is D1, and the contact position between the workpiece 1 and the cutting blade 31 of the cutter 3 is P1, the movement vector of the workpiece 1 at P1 is Vw1, and the movement vector of the cutting blade 31 is Vc1. Since the cutting point of the workpiece 1 moves on the circumference around the first axis X1, the movement vector Vw1 of the workpiece 1 is directed in the tangential direction of the workpiece 1 at the contact position P1.

  On the other hand, the movement vector Vc1 of the cutting edge 31 includes a rotation component of the cutting edge 31 and a feed component along the second axis X2. Due to the movement vector Vw1 of the workpiece 1 and the movement vector Vc1 of the cutting edge 31, a vector Vt1 is generated between the workpiece 1 and the cutting edge 31. This is a slip between the workpiece 1 and the cutting edge 31. The cutting efficiency of the workpiece 1 can be adjusted by changing the slip amount.

  As shown in FIG. 6, the offset amount is set to a larger D1 in several cutting movements including the start of cutting among a plurality of cutting movements. This position takes a larger amount of offset than the normal meshing position between the workpiece 1 and the cutter 3. Therefore, in this case, a machining error occurs, but since the amount of slip increases, cutting efficiency increases.

  On the other hand, in the latter half of the cutting movement including the final finishing cutting, the offset amount of the cutter 3 is reduced and set to D2. This position is a normal meshing position between the workpiece 1 and the cutter 3. In this case, the movement vector of the workpiece 1 at the contact position P2 (the distance from the rotation center of the workpiece is the same as P1) is Vw2, and the movement vector of the cutting edge 31 is Vc2. The movement vectors Vw1 and Vw2 of the workpiece 1 have the same speed (vector length), and the movement vectors Vc1 and Vc2 of the cutting edge 31 have the same speed (vector length). Therefore, a slip having a vector of Vt2 occurs between the workpiece 1 and the cutting edge 31.

  In this way, by setting the offset amount of the cutter in the subsequent cutting movement to a normal value smaller than the offset amount of the cutter 3 in the previous cutting movement, the moving direction of the cutting point on the workpiece 1 and the cutting edge 31 are set. The moving direction of the upper cutting point approaches and the slip vector Vt2 of the cutter 3 is set appropriately. Thereby, although the cutting efficiency is slightly lowered in the later cutting movement among the cutting movements performed a plurality of times, the burden acting on the cutting edge 31 is reduced, and the crown gear can be precisely finished.

(3) In addition, the crown gear manufacturing apparatus may be configured such that the cutter 3 can swing as shown in FIG.
Specifically, the cutting edge 31 of the cutter 3 includes a posture changing mechanism 7 that can rotate around a rotation axis X3 that is parallel to the first axis X1 through a contact position P that contacts the workpiece 1. Also good. The swing motion is performed by the fourth motor M4. By adjusting the swing angle of the cutter 3, the moving direction of the cutting edge 31 relative to the moving direction of the workpiece 1, that is, the slip can be set as appropriate.

  Thereby, for example, in the first half of the cutting process in which the workpiece 1 is roughly processed, the degree of swinging of the cutter 3 is set to be large, and the area that can be cut at a time is increased by increasing the slip relative to the workpiece 1. However, when the swing angle of the cutter 3 is set in this way, the shape of the tooth gap formed by the cutting is different from the final finished shape. Therefore, it is preferable to return the swing angle of the cutter 3 to a predetermined value in the latter half of the finish cutting.

  It should be noted that the offset amount of the cutter 3 is changed even if the swing angle of the cutter 3 is changed by setting the swing axis X3 to a position passing through the contact position P between the cutting blade 31 and the workpiece 1. Absent.

  The present invention can be used as a manufacturing apparatus and method for cutting a crown gear including a face gear by skiving.

DESCRIPTION OF SYMBOLS 1 Work 2 Work support part 3 Cutter 31 Cutting blade 32 Cutting blade formation part 33 Gripping part 34 Intermediate part 4 Cutter support part 6 Cutting control part X1 1st axis X2 2nd axis θ The inclination angle

Claims (3)

A cutting edge is formed on the tip edge, and a cutting edge forming section including at least one thread-like portion having the same cross-sectional shape as the cutting edge at any position along the direction of the rotation axis;
A gripping part fixed to the rotating shaft of the machine tool and formed in a columnar shape and having an outer diameter larger than the outer diameter of the cutting blade forming part;
Provided with a cutter provided between the cutting blade forming portion and the gripping portion and having an intermediate portion whose cross-sectional shape expands from the cutting blade forming portion toward the gripping portion;
A workpiece support that supports the workpiece rotatably around the first axis;
A cutter support portion having an inclination angle with respect to a virtual plane orthogonal to the first axis, and supporting the cutter rotatably around the second axis;
Set the cutting angle of the cutter with respect to the tilt angle and the workpiece,
When viewed along the direction of the first axis, the movement trajectory of the cutter is set in a state offset to the upper side in the rotation direction of the workpiece so as not to intersect the first axis;
A crown gear manufacturing apparatus comprising: a cutting control unit configured to cut and move the cutter on a virtual plane orthogonal to the first axis while rotating the workpiece and the cutter synchronously. While repeating the cutting movement a plurality of times,
The cutting controller, than the inclination angle of the cutter in the cutting movement of less than a predetermined number of times, the crown gear manufacturing apparatus according to 請 Motomeko 1 to set smaller the inclination angle of the cutting movement after a predetermined number of times has elapsed. While repeating the cutting movement a plurality of times,
The crown gear manufacturing apparatus according to claim 1 or 2 , wherein the cutting control unit sets the offset amount in the subsequent cutting movement to be smaller than the offset amount in the previous cutting movement.

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