Method for chamfering gears, chamfering tool, and method for manufacturing a chamfering tool.

Abstract

Provided is a gear chamfering method with which the axial-direction edge part of the tooth surface of each tooth of a gear can be chamfered in a short amount of time. This gear chamfering method comprises a chamfering step in which edge parts 15b, 15c of a plurality of teeth 12 of a gear 10 are chamfered by a chamfering tool 20 equipped with a machining blade 24. If a discretionary integer is represented as K, the number of teeth 12 is represented as Zw, and the number of machining blades 24 is represented as Zt, then in the chamfering step, the gear 10 is rotated by K・Zt / Zw around a rotation axis C1 every time the chamfering tool 20 is rotated once around a tool axis C2 in a machining posture in which the tool axis C2 is disposed non-parallel to the rotation axis C1. Due to this configuration, the machining blade 24 sequentially contacts the plurality of edge parts 15b, 15c, and the edge parts 15b, 15c are chamfered.

Description

Technical Field

[0001] The present invention relates to a chamfering method for gears, a chamfering tool for chamfering gears, and a method for manufacturing the chamfering tool.

Background Art

[0002] A method is known in which, while rotating a gear, a chamfering tool is synchronously rotated about a tool axis parallel to the rotation axis of the gear to chamfer the tooth tips of each tooth of the gear (Patent Document 1). This chamfering tool has a plurality of tool teeth around the tool axis, and chamfers by bringing the tooth tips of the tool teeth into contact with the tooth tips of the gear.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, the chamfering tool disclosed in Patent Document 1 is for chamfering the tooth tips of gears, and it is difficult to chamfer the axial edges on the tooth surfaces of each tooth of the gear. Also, a method of chamfering each of those edges one by one with the bottom edge of an end mill is known, but this method has a problem that the processing time becomes long.

[0005] The present invention has been made to solve the above-described problems, and an object thereof is to provide a chamfering method for gears, a chamfering tool, and a method for manufacturing the chamfering tool that can chamfer the axial edges on the tooth surfaces of each tooth of the gear in a short time.

Means for Solving the Problems

[0006] To achieve this objective, the present invention provides a gear chamfering method comprising a chamfering step of chamfering a gear having multiple teeth formed around a rotation axis using a chamfering tool that rotates around a tool axis. Each of the multiple teeth comprises a tooth surface which is a surface facing the circumferential direction of the gear, and an edge portion on the tooth surface in the axial direction of the rotation axis. The chamfering tool comprises at least one machining cutting edge formed around the tool axis in a shape corresponding to the shape of the edge portion. Let K be an arbitrary integer, Zw be the number of teeth, and Zt be the number of machining cutting edges. In the chamfering step, in a machining position in which the tool axis is positioned non-parallel to the rotation axis, the gear is rotated K·Zt / Zw around the rotation axis each time the chamfering tool is rotated once around the tool axis, and the machining cutting edges are sequentially brought into contact with the multiple edges to chamfer. [Effects of the Invention]

[0007] The gear chamfering method according to claim 1 is formed around the tool axis at 2 or more The system includes a chamfering step in which a chamfering tool equipped with a machining edge is used to chamfer the edges of the tooth surfaces of multiple teeth of the gear in the axial direction relative to the rotation axis. In this chamfering step, the chamfering is performed in a machining position in which the tool axis is positioned non-parallel to the rotation axis. This makes it possible to chamfer the edges of the gear while the chamfering tool and the gear rotate synchronously.

[0008] If K is an arbitrary integer, Zw is the number of teeth, and Zt is the number of cutting edges, the above synchronous rotation means that for every rotation of the chamfering tool around the tool axis, the gear rotates K·Zt / Zw around the axis of rotation. Due to this synchronous rotation, cutting edges with shapes corresponding to the edge shape sequentially contact multiple edges, and those edges are chamfered. Therefore, the edges of the gear can be chamfered in a short time.

[0009] surfaceIn the chamfering process, different cutting tools are brought into contact with the tooth tip and tooth root of a single edge to chamfer it. By independently designing the shape of the cutting tool that contacts the tooth tip and the cutting tool that contacts the tooth root, or by varying the machining position when these cutting tools make contact, the size and angle of the chamfer on the tooth tip and tooth root can be adjusted (for example, made uniform). The gear chamfering method described in claim 3 provides the following effects in addition to those of the gear chamfering method described in claim 1. The chamfering tool includes a rake face that extends from the cutting edge toward the tool axis and faces forward in the direction of rotation of the chamfering tool. Since the rake face and the cutting edge are located on a third virtual plane including the tool axis, the phase of the cutting edge rotating around the tool axis can be easily determined from the orientation of the rake face. Therefore, the initial phase of the cutting edge when it starts to rotate around the tool axis in the chamfering process can be easily determined by determining the initial phase of the cutting edge with respect to the rake face. The gear chamfering tool described in claim 4 is used in the gear chamfering method described in claim 3. The cutting edge is a portion with a radius smaller than the maximum radius of the chamfering tool and is formed on the axial tip side of the chamfering tool. The rake face extends from the position where this cutting edge is formed to the side opposite the tip side of the chamfering tool. This makes it possible to widen the rake face, which is the reference for determining the initial phase of the cutting edge, making it easier to obtain the orientation of the rake face using sensors, etc., and thus making it easier to determine the initial phase.

[0010] Claim 5 The chamfering method for the gears described is: The system includes a chamfering step in which the axial edges of the tooth surfaces of multiple teeth of a gear are chamfered in the direction of the rotation axis using a chamfering tool equipped with at least one machining edge formed around the tool axis. In this chamfering step, the chamfering is performed in a machining position in which the tool axis is positioned non-parallel to the rotation axis. This makes it possible to chamfer the edges of the gear while the chamfering tool and the gear rotate synchronously. If K is an arbitrary integer, Zw is the number of teeth, and Zt is the number of cutting edges, the above synchronous rotation means that for every rotation of the chamfering tool around the tool axis, the gear rotates K·Zt / Zw around the axis of rotation. Due to this synchronous rotation, cutting edges with shapes corresponding to the edge shape sequentially contact multiple edges, and those edges are chamfered. Therefore, the edges of the gear can be chamfered in a short time. The machining position is a state in which the tool axis, which is located on a first virtual plane containing the axis of rotation, is moved parallel to the first virtual plane in a direction perpendicular to the first virtual plane. In this case, one or more of the edges of the multiple teeth become closer to parallel with the tool axis. In the chamfering process, by bringing the machining blade into contact with this edge that has become closer to parallel with the tool axis and performing chamfering, the entire edge can be chamfered by the machining blade in a short time. As a result, since the tip side and the root side of the edge are chamfered similarly by the machining blade, the size and angle of the chamfer on the edge can be made uniform across the entire edge.

[0011] Claim 6 According to the method for chamfering gears described, 5 In addition to the effects of the gear chamfering method described, the following effects are achieved. The machining position is such that the tool axis is tilted with respect to a second virtual plane perpendicular to the rotation axis. As a result, during the chamfering process, when viewed from the axial direction of the rotation axis, the machining blade tilts toward the circumferential direction of the gear as the tool rotates around the tool axis. This tilt can cause the machining blade and the edge of the tooth to approach parallel. By bringing the machining blade into contact with the edge and performing chamfering when the two are approaching parallel, the entire edge can be chamfered by the machining blade in a short time. As a result, since the tip side and the root side of the edge are chamfered similarly by the machining blade, the size and angle of the chamfer on the edge can be made uniform across the entire edge.

[0012]

[0013]

[0014] Claim 7 The chamfering tool for gears described in As mentioned above is used in a gear chamfering method of and is as follows. The chamfering tool includes a blade portion formed around a tool axis. This blade portion includes a front rake face facing forward in the rotational direction of the chamfering tool, and Suitable a connecting surface that connects the outer edges in the radial direction between Rear side the front rake face and Rear side a rear rake face facing backward in the rotational direction of the chamfering tool. A pair of two cutting blades for chamfering the edge of the gear are formed by the intersection line between the connecting surface and the front rake face, and the intersection line between the connecting surface and Rear side the rear rake face, respectively.

[0015] Thus, for example, while one of the circumferentially adjacent edges is being chamfered by the cutting blade on the front rake face side during one rotation of the chamfering tool, the other of the adjacent edges can be chamfered by the cutting blade on the Rear side rear rake face side. In this case, compared with the case of chamfering both of the adjacent edges with the same cutting blade, the cutting blade can be formed into a shape suitable for each edge, so that it is easier to adjust the chamfering size and angle for each edge.

[0016] Claim 8 The manufacturing method of the chamfering tool described in As mentioned above is a method for manufacturing a chamfering tool used in a gear chamfering method of and is as follows. This chamfering tool includes at least one cutting blade formed around a tool axis, and a rake face that extends from the cutting blade toward the tool axis side and faces forward in the rotational direction of the chamfering tool. Suitable

[0017] ​In the gear setting process, the shape of the chamfer part to be formed when chamfering the edge of the gear, and the shape of the gear including the number of teeth Zw are set. In the rotating surface setting process, the shape of a virtual rotating surface that rotates around the tool axis facing the rotation direction of the chamfer tool is set. In the condition setting process, the initial phase of the rotating surface set in the rotating surface setting process, the machining posture in the chamfering process, an arbitrary integer K, and the number of cutting edges Zt are set.

[0018] In the subsequent acquisition process, based on the settings of the condition setting process and the gear setting process, in the machining posture, while rotating the rotating surface once around the tool axis from the initial phase, for each phase when the gear is rotated K·Zt / Zw times around the rotation axis, the intersection lines between the rotating surface and the chamfer part are respectively acquired. In the forming process, a line that contacts the plurality of intersection lines acquired in the acquisition process is used as the cutting edge, and the rotating surface on the tool axis side of the cutting edge is used as the rake face to form the chamfer tool. Therefore, the chamfer part actually formed by using this chamfer tool according to the gear chamfering method described in claim 1 can be made closer to the shape of the chamfer part set in the gear setting process.

Brief Description of the Drawings

[0019] [Figure 1] It is a perspective view of a gear and a chamfer tool showing the gear chamfering method in the first embodiment. [Figure 2] (a) is a front view of the chamfer tool, and (b) is a bottom view of the chamfer tool seen from the direction of arrow IIb in FIG. 2(a). [Figure 3] (a) is a partially enlarged front view of the gear seen from the direction of arrow IIIa in FIG. 1, and (b) is a partially enlarged plan view of the gear seen from the direction of arrow IIIb in FIG. 3(a). [Figure 4] It is a schematic diagram showing a part of the manufacturing method of the chamfer tool. [Figure 5] (a) is a front view of the chamfer tool used in the gear chamfering method in the second embodiment, and (b) is a bottom view of the chamfer tool seen from the direction of arrow Vb in FIG. 5(a). [Figure 6] It is a schematic diagram showing the gear chamfering method in the third embodiment. [Figure 7] This is a schematic diagram showing a method for chamfering gears in the fourth embodiment. [Figure 8] (a) is a front view of the chamfering tool used in the gear chamfering method of the fifth embodiment, (b) is a side view of the chamfering tool viewed from the direction of arrow VIIIb in Figure 8(a), and (c) is a bottom view of the chamfering tool viewed from the direction of arrow VIIIc in Figure 8(a). [Modes for carrying out the invention]

[0020] Preferred embodiments will be described below with reference to the attached drawings. Figure 1 is a perspective view of the gear 10 and the chamfering tool 20 (hereinafter referred to as "tool 20") showing the chamfering method for the gear 10 in the first embodiment. Figure 2(a) is a front view of the tool 20. Figure 2(b) is a bottom view of the tool 20 as seen from the direction of arrow IIb in Figure 2(a). Note that the lower half of the gear 10 is omitted from the illustration in Figure 1. Also, the rear end (upper side) of the tool 20 is omitted from the illustration in Figures 1 and 2(a).

[0021] As shown in Figure 1, the gear 10 is an external gear equipped with multiple teeth 12 (18 in this embodiment) that protrude radially outward from the outer surface of a cylindrical body centered on the rotation axis C1. The multiple teeth 12 are arranged at equal intervals around the rotation axis C1 and are identical in shape to each other. Furthermore, the multiple teeth 12 extend parallel to the rotation axis C1.

[0022] Of the outer circumferential surfaces of the cylindrical body of gear 10, the surfaces between multiple teeth 12 are the tooth root surfaces 13. Of each tooth 12, the radially leading surface is the tooth tip surface 12a, and the tooth tip surface 12a and the tooth root surface 13 are connected to form a pair of surfaces facing in the circumferential direction, which are the tooth surfaces 12b and 12c. Note that if the right side of Figure 1 is considered the front of gear 10 in the axial direction (arrow Y direction) of the rotation axis C1, then in that front view, tooth surface 12b faces clockwise and tooth surface 12c faces counterclockwise.

[0023] The intersection line between the axial end face 14 of the rotation axis C1 of the gear 10 and the tooth tip surface 12a is the edge 15a. Also, the intersection line between the end face 14 and the tooth surface 12b is the edge 15b. The intersection line between the end face 14 and the tooth surface 12c is the edge 15c. The intersection line between the end face 14 and the tooth root surface 13 is the edge 15d.

[0024] In such a gear 10, multiple teeth 12 are formed by a gear cutting device or rolling device (not shown). Subsequently, multiple edges 15b to 15d are chamfered by a tool 20. Finally, edge 15a is chamfered by another tool (not shown).

[0025] As shown in Figures 2(a) and 2(b), the tool 20 comprises a cylindrical shank 21 centered on the tool axis C2, a body 22 provided at the axial end of the shank 21 (lower side in Figure 2(a)), and a cutting edge 23 extending radially from the body 22. The body 22 is tapered as it moves away from the shank 21 in the axial direction.

[0026] The shank 21 is held by a machine tool such as a multi-tasking machine at its rear end (upper side in Figure 2(a)), which is opposite the body 22 in the axial direction. The machine tool transmits a driving force to rotate the tool 20 around the tool axis C2. This rotation of the tool 20 causes the edges 15b to 15d of the gear 10 to be chamfered by the cutting edge 23. The rotation direction Rt of the tool 20 when chamfering with the cutting edge 23 is clockwise when viewed from the axial front end as shown in Figure 2(b).

[0027] The blade portion 23 is a part that protrudes radially outward from the outer circumferential surface of the body 22, and in this embodiment, only one blade portion is formed around the tool axis C2. The blade portion 23 includes a machining blade 24 that chamfers the edges 15b to 15d, a rake face 25 extending from the machining blade 24 toward the tool axis C2, and a relief face 26 extending from the machining blade 24 toward the rear in the rotational direction Rt.

[0028] The machining edge 24 is a cutting edge formed by the intersection of the rake face 25 and the flank face 26, extending from the axial tip to the rear end of the tool 20. The shape of the machining edge 24 is determined according to the shape of the edges 15b to 15d to be chamfered. Specifically, the shape of the machining edge 24 extends perpendicularly to the tool axis C2 from the axial tip of the tool 20, and then curves in the order of convex, concave, and convex towards the rear end.

[0029] Note that the cutting edge 24 is a portion smaller than the maximum radius of the tool 20 (shank 21). That is, the cutting edge 24 is the portion on the tip side of the imaginary line L in Figure 2(a). The edges 15b to 15d of the cutting edge 24 near the imaginary line L, and the straight portion that extends from the cutting edge 24 toward the rear end of the imaginary line L, are not chamfered.

[0030] The rake face 25 is the surface for discharging chips generated during chamfering with the cutting edge 24, and faces forward in the rotational direction Rt of the cutting edge 23. The rake face 25 is located on a virtual plane Pr that includes the tool axis C2 and extends toward the rear end of the virtual line L. The lower end of the spiral supply hole 22a formed in the shank 21 opens toward this rake face 25. During chamfering (cutting) by the tool 20, cutting fluid is supplied to the rake face 25 through the supply hole 22a, and the chamfered portion is cooled, lubricated, and cleaned.

[0031] The relief surface 26 is a surface designed to avoid further contact between the chamfered portion by the machining edge 24 and the tool 20. The relief surface 26 moves away from the machining edge 24 in the circumferential direction toward the tool axis C2.

[0032] To manufacture the tool 20, the cylindrical alloy constituting the shank 21 is ground to machine the body 22, the rake face 25, and the flank face 26. Preferably, the surface roughness Rz (maximum height roughness) of the rake face 25 and flank face 26 formed by this grinding process is 1.6 or less. In this case, burrs are less likely to form when chamfering with the tool 20.

[0033] Next, with reference to Figures 1, 3(a), and 3(b), the method of chamfering the gear 10 using the tool 20 will be explained in detail. The following explanation will focus on chamfering the right edge 15b to 15d in Figure 1 using the tool 20, but the same procedure applies to chamfering the left edge 15b to 15d in Figure 1.

[0034] Figure 3(a) is a partially enlarged front view of gear 10 as seen from the direction of arrow IIIa in Figure 1 (axial direction of rotation axis C1). Figure 3(b) is a partially enlarged plan view of gear 10 as seen from the direction of arrow IIIb in Figure 3(a) (radial direction).

[0035] To chamfer the edges 15b to 15d of the gear 10 with the tool 20, first, the machining position of the tool 20 relative to the gear 10 is determined (preparation step). Next, in that machining position, the gear 10 is rotated in the rotational direction Rw around the rotation axis C1, while the tool 20 is rotated in the rotational direction Rt around the tool axis C2, so that the machining blade 24 sequentially contacts the multiple edges 15b to 15d (chamfering step). In this embodiment, the rotational direction Rw is the counterclockwise direction from tooth surface 12c to tooth surface 12b.

[0036] In this embodiment, the machining position is such that the rotation axis C1 and the tool axis C2 are orthogonal to each other, and the tip of the tool 20 is in contact with the tooth root surface 13 when viewed from the axial direction of the rotation axis C1. Since the rotation axis C1 and the tool axis C2 are orthogonal to each other, the tool axis C2 is located on a first virtual plane P1 that includes the rotation axis C1, and also on a second virtual plane P2 that is perpendicular to the rotation axis C1. In Figure 1, the axial direction of the rotation axis C1 is indicated by the arrow Y direction, the axial direction of the tool axis C2 is indicated by the arrow Z direction, and the direction perpendicular to the rotation axis C1 and the tool axis C2 is indicated by the arrow X direction.

[0037] In the chamfering process, the gear 10 is rotated K·Zt / Zw times for every one rotation of the tool 20. "K" is an arbitrary integer, and in this embodiment it is set to 1. "Zt" is the number of cutting edges 24 of the tool 20, and in this embodiment it is 1. "Zw" is the number of teeth 12 of the gear 10, and in this embodiment it is 18. That is, in the chamfering process of this embodiment, the gear 10 is rotated 1 / 18 of a rotation for every one rotation of the tool 20. The time it takes for the tool 20 to complete one rotation is one cycle in the chamfering process.

[0038] Figures 3(a) and 3(b) show the contact positions A to E between the edge portions 15b to 15d and the machining blade 24 during this one cycle. Contact position A is where the machining blade 24 contacts the circumferential center of the edge portion 15d. Contact position B is where the machining blade 24 contacts the edge portion 15b. Contact position C is where the machining blade 24 contacts the edge portion 15b at a higher position than contact position B (towards the tooth tip surface 12a). Contact position D is where the machining blade 24 contacts the edge portion 15c at the same height as contact position B. Contact position E is where the machining blade 24 contacts the edge portion 15c at the same height as contact position C.

[0039] Furthermore, Figure 3(b) shows that the position of the tool axis C2 at contact position A is indicated as axis position C2A. Similarly, Figure 3(b) shows that the positions of the tool axis C2 at contact positions B to E are indicated as axis positions C2B to C2E, respectively. Also, Figure 3(b) shows the position of the rake face 25 at each of contact positions A to E with dashed lines.

[0040] In addition, Figure 3(b) shows the shape of the chamfered portion 16d formed by chamfering the edge 15d with the machining blade 24, indicated by a dashed line. Also in Figure 3(b), the shape of the chamfered portion 16b formed by chamfering the edge 15b with the machining blade 24 near contact positions B and C is shown by a dashed line. Similarly, the shape of the chamfered portion 16c formed by chamfering the edge 15c with the machining blade 24 near contact positions D and E is shown by a dashed line.

[0041] According to Figures 3(a) and 3(b), during one cycle of the chamfering process, the cutting edge 24 continuously chamfers the edges 15b to 15d so that it passes through contact positions E, D, A, B, and C in order. When the tool 20 is moved relative to the gear 10 with respect to this one cycle, as shown in Figure 3(b), the position of the tool axis C2 moves from axis position C2E to axis position C2C, in the opposite direction to the rotational direction Rw, while the tool 20 rotates in the rotational direction Rt.

[0042] At contact position A, the tool axis C2 (axis position C2A) and the cutting edge 24 are aligned on a first virtual plane P1 that passes through the center of the circumferential direction of the edge 15d. Therefore, the relative synchronous rotational movement of the tool 20 with respect to the gear 10 is symmetrical on both sides of this first virtual plane P1. Thus, chamfered portions 16b to 16d can be formed symmetrically on both sides of the gear 10 in the circumferential direction with respect to contact position A.

[0043] In the preparation step, the initial phase of the machining blade 24 is determined such that, at the contact position A of the chamfering step, the tool axis C2 and the machining blade 24 are aligned on a first virtual plane P1 passing through the center of the circumferential direction of the edge portion 15d. The initial phase of the machining blade 24 is the position of the machining blade 24 relative to the tool axis C2 and the gear 10 when the tool 20 (machining blade 24) begins to rotate. By determining the initial phase in this way, the chamfered portions 16b to 16d can be formed symmetrically with respect to the contact position A, as described above.

[0044] The initial phase may be a state in which the tool axis C2 and the cutting edge 24 are aligned on the first virtual plane P1 described above, or it may be a state in which the gear 10 and tool 20 are rotated synchronously according to the chamfering process from that state. For example, the positional relationship between the tool axis C2, the cutting edge 24 and the gear 10 at contact positions B to E may be used as the initial phase. Alternatively, the initial phase may be a state in which the gear 10 is rotated synchronously while the tool 20 is rotated 90 or 180 degrees from the state at contact position A.

[0045] Furthermore, if the machining blade 24 and the gear 10 interfere in the initial phase, it is preferable to move the tool 20 away from the gear 10 in the axial or radial direction of the rotation axis C1 beforehand, and then move the tool 20 closer to the gear 10 during the chamfering process. This allows the machining blade 24 to gradually cut deeper into the edges 15b to 15d, thereby suppressing chipping of the machining blade 24 and the edges 15b to 15d.

[0046] Furthermore, as explained with reference to Figure 2(b), since the machining edge 24 and the rake face 25 are located on a virtual plane Pr that includes the tool axis C2, the phase of the machining edge 24 rotating around the tool axis C2 can be easily determined from the orientation of the rake face 25. Therefore, in the preparation step, the initial phase of the machining edge 24 can be easily determined by determining the initial phase of the machining edge 24 with reference to the rake face 25.

[0047] Furthermore, as explained with reference to Figure 2(a), since the rake face 25 extends further towards the rear end than the virtual line L (machining blade 24), the rake face 25, which is the reference for determining the initial phase of the machining blade 24, can be made wider. This makes it easier to acquire the orientation of the rake face 25 using sensors, etc., and makes it easier to determine the initial phase.

[0048] Let's return to Figures 3(a) and 3(b) for explanation. The chamfered portion 16d is formed by chamfering almost the entire edge 15d with the protruding tip portion of the machining blade 24. Therefore, the shape and angle of the chamfered portion 16d can be made substantially the same throughout the entire circumferential direction.

[0049] Here, when the end face 14 of the gear 10 and the chamfered portions 16b to 16d are parallel, the angle of the chamfered portions 16b to 16d is set to 0 degrees. At contact positions B to E, the inclination angle of the rake face 25 (machining blade 24) relative to the end face 14 is approximately the same as the angle of the chamfered portions 16b and 16c. Therefore, the more the timing of forming the chamfered portions 16b and 16c with the machining blade 24 differs between contact positions B and D and contact positions C and E, the more the inclination angle of the rake face 25 changes, and the more the angles of the chamfered portions 16b and 16c shift. In the third and fourth embodiments described later, a method to make it less likely for the angles of the chamfered portions 16b and 16c to shift will be explained.

[0050] As described above, in the chamfering process in this embodiment, the synchronous rotation of the gear 10 and the tool 20 repeats one cycle in which the edges 15c, 15d, and 15b are successively chamfered by the machining blade 24, thereby sequentially chamfering the edges 15b to 15d of multiple teeth 12. Therefore, the edges 15b to 15d of the gear 10 can be chamfered in a short time.

[0051] In this chamfering process, as described above, a machining blade 24 with a shape corresponding to the shape of the edges 15b to 15d is used. The manufacturing method of the tool 20, including the design method of this machining blade 24, will be explained with reference to Figures 1 and 4. Figure 4 is a schematic diagram showing a part of the manufacturing method of the tool 20.

[0052] First, the shape of the gear 10 to be chamfered using the tool 20 is set (gear setting process). This shape of the gear 10 includes the dimensions of the gear 10, the number of teeth 12 Zw, and the shape of the chamfered portions 16b to 16d that will be formed when the edges 15b to 15d are chamfered.

[0053] Next, the shape of a virtual rotation plane that rotates around the tool axis C2 in the direction of rotation Rt of the tool 20 is set (rotation plane setting step). This virtual rotation plane is the plane corresponding to the rake face 25. In this embodiment, the virtual rotation plane set in the rotation plane setting step is set to a virtual plane Pr that includes the tool axis C2.

[0054] Next, the initial phase of the virtual plane Pr set in the rotation plane setting step, the machining position in the chamfering step using the tool 20 under design, an arbitrary integer K, and the number of cutting edges 24 of the tool 20 Zt are set (condition setting step). In this embodiment, the machining position, integer K, and number Zt are as described above in the description of the chamfering step. The initial phase of the virtual plane Pr is the same as the initial phase of the cutting edge 24 (rake face 25) in the chamfering step described above.

[0055] Next, similar to the chamfering process, based on the settings in the condition setting process and the gear setting process, the gear 10 is rotated K·Zt / Zw around the rotation axis C1 while the virtual plane Pr is rotated once around the tool axis C2 from the initial phase in the machining position (acquisition process). In this acquisition process, the intersection lines 28 between the virtual plane Pr and the chamfered portions 16b to 16d are acquired for each phase when the gear 10 and the virtual plane Pr are rotated synchronously.

[0056] Figure 4 shows some of the multiple intersection lines 28 acquired in the acquisition process, arranged on a virtual plane Pr. Furthermore, Figure 4 schematically illustrates the number, size, orientation, and position of the intersection lines 28 to facilitate understanding of the design method for the shape of the machining blade 24.

[0057] In the forming process following the acquisition process, the tool 20 is formed (designed) by defining the cutting edge 24 as a line (envelope) that is tangent to multiple intersection lines 28 on the opposite side of the tool axis C2, and defining the rake face 25 as a virtual plane Pr that is closer to the tool axis C2 than the cutting edge 24. As a result, the cutting edge 24 of the tool 20 formed in the forming process can actually chamfer the edges 15b to 15d at a position close to the chamfered portions 16b to 16d set in the gear setting process. Therefore, the chamfered portions 16b to 16d that are actually formed by this chamfering can be made to closely resemble the shape of the chamfered portions 16b to 16d set in the gear setting process.

[0058] Furthermore, after the molding process, the shapes of the chamfered portions 16b to 16d actually formed by the tool 20 may be compared with the shapes of the chamfered portions 16b to 16d set in the gear setting process to determine whether it is necessary to readjust the shape of the tool 20 (determination process). Note that the shapes of the chamfered portions 16b to 16d actually formed by the tool 20 may be calculated on a PC based on the shape of the machining blade 24 determined in the molding process.

[0059] In the decision-making process, for example, if the actual angle of the chamfered portion 16b to 16d is within -10 degrees to +10 degrees relative to the set angle of the chamfered portion 16b to 16d, it is determined that readjustment is not necessary. On the other hand, if it is outside that range, it is determined that readjustment is necessary. However, the method for determining whether readjustment is necessary may be appropriately changed depending on the shape of the gear 10 and the processing conditions.

[0060] If it is determined in the judgment step that a reset is necessary, at least one of the settings in the rotation surface setting step and the condition setting step is changed (change step). After the change step, the acquisition step and the forming step are performed again to form (design) the tool 20. If necessary, the judgment step and the forming step may be repeated to complete the tool 20. As a result, the chamfered portions 16b to 16d actually formed on the tool 20 can be made to more closely resemble the shape of the chamfered portions 16b to 16d set in the gear setting step.

[0061] Next, a second embodiment will be described with reference to Figures 5(a) and 5(b). In the first embodiment, a tool 20 equipped with one cutting edge 24 was described. In contrast, in the second embodiment, a chamfering tool 30 (hereinafter referred to as "tool 30") equipped with two cutting edges 32 and 36 will be described. Note that parts identical to those in the first embodiment are denoted by the same reference numerals and their descriptions will be omitted below.

[0062] Figure 5(a) is a front view of the chamfering tool 30 used in the chamfering method for the gear 10 in the second embodiment. Figure 5(b) is a bottom view of the chamfering tool 30 as seen from the direction of arrow Vb in Figure 5(a). Note that the rear end (upper side) of the tool 30 is not shown in Figure 5(a).

[0063] Tool 30 is for chamfering the same gear 10 as in the first embodiment. Tool 30 comprises a shank 21, a body 22, and two cutting edges 31 and 35 that protrude radially from the outer circumferential surface of the body 22 and are formed around the tool axis C2.

[0064] The two cutting edges 31 and 35 are positioned 180 degrees apart from each other around the tool axis C2. Cutting edge 31 includes a cutting edge 32 for chamfering the edges 15b to 15d of the gear 10, a rake face 33 extending from the cutting edge 32 toward the tool axis C2, and a relief face 34 extending from the cutting edge 32 toward the rear in the rotational direction Rt. Similarly, cutting edge 35 includes a cutting edge 36, a rake face 37, and a relief face 38. Note that the rake faces 33, 37 and the relief faces 34, 38 have the same functions as the rake face 25 and relief face 26 in the first embodiment, so their description is omitted.

[0065] The machining edge 32 is a cutting edge formed by the intersection of the rake face 33 and the flank face 34, extending from the leading edge to the trailing edge in the axial direction of the tool 30. The machining edge 36 is a cutting edge formed by the intersection of the rake face 37 and the flank face 38, extending from the leading edge to the trailing edge in the axial direction of the tool 30. Both machining edges 32 and 36 are located on a virtual plane Pr that includes the tool axis C2.

[0066] Figure 5(a), a front view of the rake face 33, shows a machining edge 36 rotated 180 degrees around the tool axis C2 and superimposed on the machining edge 32, as indicated by a dashed line. According to Figure 5(a), at the tip of the tool 30, the machining edge 32 is located radially outward from the machining edge 36. On the other hand, at the rear end of the tool 30, the machining edge 36 is located radially outward from the machining edge 32.

[0067] Of these machining blades 32 and 36, the portions located relatively radially outward mainly chamfer the edges 15b to 15d to form chamfered portions 16b to 16d. The shape of these outer portions is designed in the same way as the machining blade 24 of the first embodiment. On the other hand, the shape of the portions located relatively radially inward of the machining blades 32 and 36 is designed considering factors such as strength and ease of manufacturing.

[0068] The chamfering method in the second embodiment will be described mainly in terms of the differences from the chamfering method in the first embodiment. In the chamfering process using the tool 30 of the second embodiment, when any integer K is set to 1, first, while the tool 30 rotates half a turn, a continuous edge portion 15b to 15d is chamfered by the machining blade 32. Next, while the tool 30 rotates another half turn, the continuous edge portions 15b to 15d that are adjacent in the circumferential direction to the chamfered edge portions 15b to 15d are chamfered by the machining blade 36.

[0069] Here, if the number of teeth 12 of gear 10, Zw, is odd, the edges 15b to 15d that were chamfered by the machining tool 32 in the first rotation of gear 10 are chamfered by the machining tool 36 in the second rotation. At this time, the portion of the machining tool 36 located radially outward from the machining tool 32 contacts and chamfers the edges 15b to 15d, while the rest is not chamfered.

[0070] Similarly, the edges 15b to 15d of the gear 10, which were chamfered by the machining blade 36 during the first rotation, are chamfered by the machining blade 32 during the second rotation. At this time, the portion of the machining blade 32 located radially outward from the machining blade 36 contacts and chamfers the edges 15b to 15d, while the rest is not chamfered.

[0071] Furthermore, if the number of teeth 12 of gear 10, Zw, is even, the machining blades 32 and 36 will continue to chamfer the same edges 15b to 15d. Therefore, if gear 10 has completed more than one rotation during the chamfering process, the synchronized rotation of gear 10 and tool 30 is stopped. After that, the gear 10 is rotated by 1 / Zw, or tool 30 is rotated by 1 / 2 rotation to change the phase, and then the synchronized rotation of gear 10 and tool 30 is restarted. After this restart, the edges 15b to 15d are chamfered by different machining blades 32 and 36 than before the restart, similar to the second rotation when the number of teeth 12, Zw, is odd.

[0072] Furthermore, if the number of teeth Zw in the 12 teeth is even, the machining position can be changed before and after restarting synchronous rotation during the chamfering process. This allows the size and angle of the chamfer on the edges 15b to 15d to be changed between the first and second rotations.

[0073] Furthermore, in either case, the tooth tip surface 12a side of the edge portions 15b to 15d of a single tooth 12 can be chamfered by the machining blade 36, and the tooth root surface 13 side of the edge portions 15b to 15d can be chamfered by the machining blade 32. This allows the shapes of the machining blades 32 and 36 for the chamfering portions 15b to 15d to be set independently. Therefore, the size and angle of the chamfering on the edge portions 15b to 15d can be adjusted (for example, made uniform) on the tooth tip surface 12a side and the tooth root surface 13 side.

[0074] Next, a third embodiment will be described with reference to Figure 6. In the first embodiment, a case was described in which the gear 10 is chamfered by the tool 20 in a machining position in which the rotation axis C1 and the tool axis C2 are perpendicular to each other. In the third embodiment, a case will be described in which the gear 10 is chamfered by the chamfering tool 40 (hereinafter referred to as "tool 40") in a machining position in which the tool axis C2 is tilted in the direction of arrow Y from the machining position of the first embodiment. Note that parts that are the same as in the first embodiment are denoted by the same reference numerals and their descriptions are omitted below.

[0075] Figure 6 is a schematic diagram showing a chamfering method for gear 10 in the third embodiment. Figure 6 shows a set of tooth surfaces 12b and 12c that are circumferentially opposed to each other, representing a portion of the gear 10's circumferential direction. In Figure 6, the gear 10 has its edges 15b to 15d chamfered, forming chamfered portions 16b to 16d. Furthermore, Figure 6 schematically shows only the tool shaft C2 and the cutting edge 41 of the tool 40 used to chamfer gear 10.

[0076] The cutting edge 41 of the tool 40 is a cutting edge formed around the tool axis C2, extending from the axial tip to the rear end of the tool 40. The tool 40, including the cutting edge 41, is substantially identical to the tool 20 of the first embodiment, except for some differences in shape. The shape of the cutting edge 41 is designed by changing the machining position in the acquisition process as described in the third embodiment below, similar to the design method described in the first embodiment.

[0077] The chamfering method in the third embodiment will be described primarily in terms of its differences from the chamfering method in the first embodiment. In the machining position of the third embodiment, the tool axis C2 is located on the first virtual plane P1 (see Figure 3(b)), which is the YZ plane containing the rotation axis C1 (see Figure 1). Furthermore, in this machining position, the tool axis C2 is tilted by an angle θ in the direction of arrow Y with respect to the second virtual plane P2 (see Figure 3(b)), which is the XZ plane. In Figure 6, a dashed line 42 is shown extending parallel to the second virtual plane P2 from the tip of the tool axis C2. The angle between this virtual line 42 and the tool axis C2 is the angle θ.

[0078] When the chamfering process is performed in this machining position, the machining blade 41 tilts in the circumferential direction of the gear 10 as the tool 40 rotates, when viewed from the direction of arrow Y (the axial direction of the rotation axis C1). As a result, the machining blade 41 and the edges 15b and 15c of the tooth 12 (the parts before the chamfering portions 16b and 16c are formed) may become nearly parallel. By adjusting the inclination angle θ, the machining blade 41 is brought into contact with the edges 15b and 15c when they become nearly parallel, and chamfering is performed. This allows the entire edge 15b and 15c to be chamfered by the machining blade 41 in a short time. As a result, both the tooth tip side and the tooth root side of the edge 15b and 15c are chamfered similarly by the machining blade 41.

[0079] Specifically, as explained using Figure 3(b), the inclination angle of the machining blade 41 when it contacts the edges 15b and 15c, with respect to the end face 14, can be made uniform on both the tooth tip and tooth root sides. Therefore, the size and angle of the chamfer on the edges 15b and 15c by the machining blade 41 can be made uniform across the entire edge 15b and 15c.

[0080] Next, the fourth embodiment will be described with reference to Figure 7. In the first embodiment, the case in which the gear 10 is chamfered by the tool 20 in a machining position in which the rotation axis C1 and the tool axis C2 are orthogonal to each other was described. In the fourth embodiment, the case in which the gear 10 is chamfered by the chamfering tool 50 (hereinafter referred to as "tool 50") in a machining position in which the tool axis C2 is moved parallel in the direction of arrow X from the machining position of the first embodiment. Note that parts that are the same as in the first embodiment are denoted by the same reference numerals and their descriptions are omitted below.

[0081] Figure 7 is a schematic diagram showing the chamfering method for the gear 10 in the fourth embodiment. Similar to Figure 6, Figure 7 shows a portion of the gear 10 in the circumferential direction. Furthermore, the gear 10 shown in Figure 7 has its edges 15b to 15d chamfered, forming chamfered portions 16b to 16d. Also, in Figure 7, only the tool shaft C2 and the cutting edge 51 of the tool 50 used to chamfer the gear 10 are schematically shown.

[0082] The cutting edge 51 of the tool 50 is a cutting edge formed around the tool axis C2, extending from the axial tip to the rear end of the tool 50. The tool 50, including the cutting edge 51, is substantially identical to the tool 20 of the first embodiment, except for some differences in shape. The shape of the cutting edge 51 is designed by changing the machining position in the acquisition process as described in the fourth embodiment below, similar to the design method described in the first embodiment.

[0083] The chamfering method in the fourth embodiment will be described mainly in terms of the differences from the chamfering method in the first embodiment. In the machining position of the fourth embodiment, the tool axis C2 is parallel to the direction of arrow Z, and the tool axis C2 has been moved in parallel from the first virtual plane P1 (see Figure 3(b)) in the direction of arrow X, which is perpendicular to the first virtual plane P1.

[0084] In this machining position, one or more of the edges 15b, 15c of the multiple teeth 12 (the parts before the chamfered portions 16b, 16c are formed) approach parallel to the tool axis C2. In Figure 7, when the tool 50 is pointed downwards, the edge 15b of the tooth 12 in the upper right of the gear 10 (the edge of the tooth surface 12b) approaches parallel to the tool axis C2.

[0085] In the chamfering process, the cutting blade 51 is brought into contact with the edge 15b, which is nearly parallel to the tool axis C2, to perform chamfering. This allows the entire edge 15b to be chamfered by the cutting blade 51 in a short amount of time. As a result, both the tooth tip side and the tooth root side of the edge 15b are chamfered similarly by the cutting blade 51.

[0086] Specifically, as explained using Figure 3(b), the inclination angle of the machining blade 51 when it contacts the edge portion 15b, with respect to the end face 14, can be made uniform on both the tooth tip side and the tooth root side. Therefore, the size and angle of the chamfer on the edge portion 15b by the machining blade 51 can be made uniform across the entire edge portion 15b.

[0087] After chamfering the edge 15b, the chamfering process is performed by changing a part of the machining position in order to also chamfer the edge 15c. As described above with reference to Figure 7, when the tool 50 is pointed downwards, the edge 15b of the upper right tooth 12 of the gear 10 and the tool axis C2 become nearly parallel. At this time, the edge 15c of the upper left tooth 12 of the gear 10 (the edge of the tooth surface 12c) also becomes nearly parallel to the tool axis C2.

[0088] Therefore, in the chamfering process for the edge portion 15c, the machining position (position in the direction of arrow X) is adjusted so that the machining blade 51 comes into contact with the edge portion 15c, which is nearly parallel to the tool axis C2, and the edge portion 15c is chamfered. As a result, similar to the chamfering of the edge portion 15b, the size and angle of the chamfer on the edge portion 15c by the machining blade 51 can be made uniform across the entire edge portion 15c.

[0089] Next, a fifth embodiment will be described with reference to Figures 8(a) to 8(c). In the first embodiment, a tool 20 in which one machining edge 24 is formed on the blade portion 23 was described. In the fifth embodiment, a chamfering tool 60 (hereinafter referred to as "tool 60") in which two machining edges 62 and 64 are formed on the blade portion 61 will be described. Note that parts identical to those in the first embodiment are denoted by the same reference numerals and their descriptions are omitted below.

[0090] Figure 8(a) is a front view of the tool 60 used in the chamfering method for the gear 10 in the fifth embodiment. Figure 8(b) is a side view of the tool 60 as seen from the direction of arrow VIIIb in Figure 8(a). Figure 8(c) is a bottom view of the tool 60 as seen from the direction of arrow VIIIc in Figure 8(a). Note that the rear end (upper side) of the tool 60 is not shown in Figures 8(a) and 8(b).

[0091] The tool 60 is for chamfering the same gear 10 as in the first embodiment. The tool 60 comprises a cylindrical shank 21 centered on the tool axis C2, a cylindrical body 22 provided at the axial end of the shank 21, and a single cutting edge 61 extending radially from the outer circumferential surface of the body 22.

[0092] The blade portion 61 has a front rake face 63 facing forward in the rotation direction Rt, and a rearward facing in the rotation direction Rt. Rear side 65 and the front scoop face 63 Rear side It includes a connecting surface 66 that connects the radially outer edges of 65. The cutting edge 62 is formed by the intersection line of the front rake face 63 and the connecting surface 66. Rear side The cutting edge 64 is formed by the intersection line of 65 and the connecting surface 66. The cutting edges 62 and 64 are cutting edges formed from the axial tip to the rear end of the tool 60.

[0093] The front rake face 63 is a surface for discharging chips generated during chamfering with the cutting edge 62. The lower end of the spiral supply hole 68 formed in the shank 21 opens toward the front rake face 63. When chamfering is performed by the tool 60, cutting fluid is supplied to the front rake face 63 through the supply hole 68, cooling, lubricating, and cleaning the chamfered area.

[0094] C The lower end of the spiral supply hole 69 formed in the shank 21, Rear side It opens towards 65. When chamfering with tool 60, cutting fluid flows through the supply hole 69. Rear side It is supplied to 65, where the chamfered portion is cooled, lubricated, and cleaned.

[0095] Furthermore, the front rake face 63 and Rear side Since 65 faces in opposite directions, the spiral directions of the supply holes 68 and 69 that supply cutting fluid to them are also opposite. However, the supply holes 68 and 69 are formed radially offset from each other. This allows supply holes 68 and 69 with different orientations to be formed in the shank 21 without interfering with each other.

[0096] As described above, the cutting edge 61 of the tool 60 has a pair of cutting blades 62 and 64. Therefore, by adjusting the machining position during the chamfering process, the edge 15b can be chamfered with the cutting blade 62 while the edge 15c adjacent to the edge 15b in the circumferential direction is chamfered with the cutting blade 64 during one rotation of the tool 60. In this case, compared to the first embodiment, where both adjacent edges 15b and 15c are chamfered with the same cutting blade 24, the cutting blades 62 and 64 can be formed in shapes suitable for each edge 15b and 15c, making it easier to adjust the size and angle of the chamfer on each edge 15b and 15c.

[0097] Specifically, the machining blade 62 and the front rake face 63 are inclined forward in the rotational direction as they move towards the rear end. This inclination is set so that when the machining blade 62 and the edge 15b come into contact, their contact area widens from the tooth tip side to the tooth root side. As a result, the entire edge 15b can be chamfered by the machining blade 62 in a short time, and both the tooth tip side and the tooth root side of the edge 15b are chamfered similarly by the machining blade 62. Therefore, the size and angle of the chamfer can be made uniform across the entire edge 15b.

[0098] Similarly, the machining blade 64 and Rear side As the cutting edge 65 approaches the rear end, it is inclined towards the rear in the direction of rotation. This inclination is set so that when the cutting edge 64 and the edge 15c come into contact, their contact area widens from the tooth tip side to the tooth root side. As a result, the entire edge 15c can be chamfered by the cutting edge 64 in a short time, and both the tooth tip side and the tooth root side of the edge 15c are chamfered similarly by the cutting edge 64. Therefore, the size and angle of the chamfer can be made uniform across the entire edge 15c.

[0099] Although the present invention has been described above based on embodiments, it can be easily inferred that the present invention is not limited in any way to the above embodiments, and that various improvements and modifications are possible without departing from the spirit of the present invention.

[0100] The values ​​given in the above embodiment are merely examples, and it is certainly possible to use other values. For example, the number Zt of machining edges 24, 32, 36, 41, 51, 62, 64 (hereinafter referred to as "machining edges 24, etc.") provided on the tool 20-60 may be one or two or more. The surface roughness Rz of the rake faces 25, 33, 37 and the flank faces 26, 34, 38, etc. may be greater than 1.6.

[0101] In the above embodiment, the case in which the gear 10 is an external gear was described, but it is not limited to this. The gear 10 may also be an internal gear in which multiple teeth 12 protrude radially inward from the inner circumferential surface of an annular member. Furthermore, the tooth trace direction in which the teeth 12 extend is not limited to being parallel to the rotation axis C1, but may also be inclined with respect to the rotation axis C1.

[0102] In the above embodiment, the case in which the supply holes 22a, 68, and 69 of the tools 20 and 60 are formed in a spiral shape was described, but the invention is not limited to this. For example, the supply holes 22a, 68, and 69 may be formed in a linear shape. In addition, spiral or linear supply holes 22a, 68, and 69 may be provided in the tools 30, 40, and 50.

[0103] In the above embodiment, the case in which the machining edges 24, 32, 36, 41, and 51 are located on a virtual plane Pr that includes the tool axis C2 was described. However, the machining edges 24, 32, 36, 41, and 51 do not necessarily have to be located on the virtual plane Pr, as is the case with machining edges 62 and 64. In this case, it is preferable to provide a reference plane for determining the initial phase of the machining edges 24, etc., on the outer circumferential surface of the shank 21 or body 22. It is preferable that this reference plane is parallel to the virtual plane Pr in order to make it easier to identify the phase of the machining edges 24, etc., that rotate around the tool axis C2.

[0104] In the above embodiment, the case in which the edges 15b and 15c are chamfered using the same cutting edges 24, 32, 36, 41, and 51 of the same tools 20 to 50 was described, but the embodiment is not limited to this. The machining position, machining conditions, and the shape of the tools 20 to 50 can be appropriately changed so that only the edges 15b are chamfered by the tools 20 to 50. In this case, a different tool from the tools 20 to 50 used to chamfer the edges 15b can be used so that only the edges 15c are chamfered.

[0105] Furthermore, in the second embodiment described above, a machining blade 32 for chamfering the tooth root side of the edges 15b to 15d and a machining blade 36 for chamfering the tooth tip side of the edges 15b to 15d are provided on a single tool 30, but this is not limited to this. A tool for chamfering the tooth root side of the edges 15b to 15d and a tool for chamfering the tooth tip side of the edges 15b to 15d may be provided separately. For example, the edges 15b to 15d may be chamfered overall with tool 20, and then only the tooth tip side of the edges 15b to 15d may be further chamfered with another tool.

[0106] In the above embodiment, the case was described in which the rotation direction Rw of the gear 10 and the rotation direction Rt of the tools 20-60 are almost identical in the vicinity of the chamfered portion during the chamfering process, but it is not limited to this. The rotation direction Rw may be in the opposite direction to this identical tracing direction. In the case of the opposite direction, the machining blade 24 etc. quickly chamfers the edges 15b-15d of the gear 10 to form chamfered portions 16b-16d, so the angle of the chamfered portions 16b-16d tends to be small. In this case, the angle of the chamfered portions 16b-16d can be increased and adjusted by reducing the outer diameter of the tools 20-60. In other words, it is easier to reduce the outer diameter of the tools 20-60 in the case of the opposite direction compared to the case of the tracing direction.

[0107] In the above embodiments, the machining posture in the chamfering process was illustrated, but the machining posture is not limited to the illustrated one. The machining posture is sufficient as long as the rotation axis C1 and the tool axis C2 are arranged non-parallel to each other. For example, the machining posture may be as shown in the third embodiment, with the tool axis C2 tilted in the direction of arrow Y with respect to the second virtual plane P2, or as shown in the fourth embodiment, with the tool axis C2 translated parallel to the first virtual plane P1 in a direction perpendicular to the first virtual plane P1.

[0108] In the above embodiment, the case in which the edges 15b to 15d of the gear 10 are chamfered by tools 20 to 60 during the chamfering process has been described, but it is not limited to this. The machining position and the shape of tools 20 to 60 may be changed so that the edges 15b and 15c of the gear 10 are chamfered but the edge 15d is not. Conversely, the machining position and the shape of tools 20 to 60 may be changed so that the edge 15d is chamfered but the edges 15b and 15c are not. Furthermore, the machining position and the shape of tools 20 to 60 may be changed so that the edge 15a of the gear 10 is also chamfered by tools 20 to 60.

[0109] In the chamfering process using tools 20, 30, 40, and 60, the machining position may be changed so that only one of the edges 15b and 15c is chamfered and the other is not. In this case, as in the fourth embodiment described above, after changing a part of the machining position, only the other of the edges 15b and 15c that was not chamfered before the change may be chamfered.

[0110] In the above embodiment, the case where any integer K in the chamfering process is 1 is given as an example, but this integer K may be 2 or more. However, in the chamfering process when the integer K is 1, multiple teeth 12 arranged in the circumferential direction can be chamfered by the machining blade 24, etc., without skipping any teeth. In the chamfering process when the integer K is 2 or more, multiple teeth 12 arranged in the circumferential direction are chamfered by the machining blade 24, etc., with one or more teeth being skipped.

[0111] For example, when the integer K is 2, multiple teeth 12 are chamfered, skipping one tooth at a time. In this case, if the number of teeth 12 Zw is odd, the teeth 12 skipped in the first rotation of the gear 10 are chamfered in the second rotation. That is, when the integer K is 2 and the number of teeth 12 Zw is odd, the same chamfer can be applied to each of the multiple teeth 12 without pausing the synchronous rotation of the gear 10 and the tools 20-60, just as when the integer K is 1. This is also true when the integer K and the number of teeth 12 Zw are relatively prime.

[0112] When the integer K is 2 and the number of teeth Zw is even, or when the integer K and the number of teeth Zw are not relatively prime, it is necessary to temporarily suspend the synchronous rotation and then restart the synchronous rotation by rotating only one of the gear 10 or the tools 20-60, as in the chamfering process of the second embodiment described above. In this case, the machining position and other settings can be changed before and after restarting the synchronous rotation. This makes it possible to change the size and angle of the chamfer on the teeth 12 before and after restarting the synchronous rotation. [Explanation of symbols]

[0113] 10 gears 12 teeth 12b, 12c tooth surface 15b,15c Edge 16b, 16c Chamfered section 20, 30, 40, 50, 60 Chamfering Tools 24,32,36,41,51,62,64 Machining blade 25, 33, 37 Scoop surface 61 Blade part 63 Front scoop face 65 Rear side 66 Connecting surface C1 Rotation axis C2 tool axis P1 First virtual plane P2 Second virtual plane Pr virtual plane (third virtual plane, plane of revolution)

Claims

1. A method for chamfering a gear, comprising a chamfering step of chamfering a gear having multiple teeth formed around a rotating axis using a chamfering tool that rotates around a tool axis, The multiple teeth have tooth surfaces which are surfaces facing the circumferential direction of the gear, Each of the tooth surfaces comprises the axial edge of the rotation axis, The chamfering tool comprises two or more cutting edges formed around the tool axis in a shape corresponding to the shape of the edge, Let K be an arbitrary integer, Zw be the number of teeth, and Zt be the number of cutting edges. The chamfering step is characterized in that, in a machining position in which the tool axis is positioned non-parallel to the rotation axis, the gear is rotated K・Zt / Zw around the rotation axis each time the chamfering tool is rotated once around the tool axis, so that the machining blades sequentially contact a plurality of edges to chamfer, and different machining blades are brought into contact with the tooth tip side and tooth root side of one edge to chamfer, as described in claim 1.

2. The method for chamfering a gear according to claim 1, characterized in that the machining position is such that the tool axis is located on a first virtual plane including the rotation axis.

3. The chamfering tool has a rake face that extends from the cutting edge toward the tool axis and faces forward in the rotational direction of the chamfering tool, The rake face and the cutting edge are located on a third virtual plane including the tool axis, The method for chamfering a gear according to claim 1, characterized in that the initial phase of the machining blade when it starts to rotate around the tool axis in the chamfering step is determined with reference to the rake face.

4. The chamfering tool used in the gear chamfering method according to claim 3, The cutting edge is a portion with a radius smaller than the maximum radius of the chamfering tool, and is formed on the axial tip side of the chamfering tool. A chamfering tool characterized in that the rake face extends from the position where the cutting edge is formed toward the opposite side from the tip.

5. A method for chamfering a gear, comprising a chamfering step of chamfering a gear having multiple teeth formed around a rotating shaft with a chamfering tool that rotates around a tool axis, The multiple teeth have tooth surfaces which are surfaces facing the circumferential direction of the gear, Each of the tooth surfaces comprises the axial edge of the rotation axis, The chamfering tool comprises at least one cutting edge formed around the tool axis in a shape corresponding to the shape of the edge, and a tip which is the end on one side of the tool axis in the axial direction. Let K be an arbitrary integer, Zw be the number of teeth, and Zt be the number of cutting edges. In the chamfering process, with the tool axis positioned non-parallel to the rotation axis, the gear is rotated K・Zt / Zw around the rotation axis each time the chamfering tool is rotated once around the tool axis, causing the cutting edge to sequentially contact multiple edges and perform chamfering. The aforementioned machining position is a state in which the tool axis, which is located on a first virtual plane including the rotation axis, is moved parallel to the first virtual plane in a direction perpendicular to the first virtual plane. A method for chamfering a gear, characterized in that the machining blade is formed from the tip of the chamfering tool toward the other end in the axial direction of the tool shaft, and the edge in the axial direction of the rotation shaft of the tooth root surface, which is the surface between a plurality of teeth, is chamfered at the tip side of the machining blade.

6. The method for chamfering a gear according to claim 5, characterized in that the machining position is such that the tool axis is inclined with respect to a second virtual plane perpendicular to the rotation axis.

7. A chamfering tool used in a chamfering method in which a gear having multiple teeth formed around a rotating shaft is chamfered with a machining blade provided on a chamfering tool that rotates around a tool axis, wherein the tool axis is positioned non-parallel to the rotating shaft, and the rotation of the chamfering tool around the tool axis and the rotation of the gear around the rotating shaft are synchronized, and the machining blade, which is formed in a shape corresponding to the shape of the edge, is sequentially brought into contact with the axial edge of the tooth surface of the multiple teeth on the rotating shaft, to chamfer the edge, The chamfering tool comprises a cutting edge formed around the tool axis, The aforementioned blade portion is The front rake face of the chamfering tool facing forward in the direction of rotation, The rear surface of the chamfering tool facing the rear in the direction of rotation, It comprises a connecting surface that connects the radially outer edges of the front scoop surface and the rear surface, A chamfering tool characterized in that a pair of processing blades for chamfering the edges are formed by the intersection lines of the connecting surface and the front rake surface, and the intersection lines of the connecting surface and the rear surface.

8. A method for manufacturing a chamfering tool used in a chamfering method in which a gear having a plurality of teeth formed around a rotating shaft is chamfered by a chamfering tool that rotates around a tool axis, The multiple teeth have tooth surfaces which are surfaces facing the circumferential direction of the gear, Each of the tooth surfaces comprises the axial edge of the rotation axis, The chamfering tool comprises at least one cutting edge formed around the tool axis, The tool comprises a rake face extending from the cutting edge toward the tool axis and facing forward in the rotational direction of the chamfering tool. Let K be an arbitrary integer, Zw be the number of teeth, and Zt be the number of cutting edges. In the chamfering method described above, with the tool axis positioned non-parallel to the rotation axis in a machining position, each time the chamfering tool is rotated once around the tool axis, the gear is rotated K・Zt / Zw around the rotation axis, causing the machining blade to sequentially contact multiple edges to perform chamfering. The method for manufacturing the aforementioned chamfering tool is: A gear setting step of setting the shape of the gear, including the shape of the chamfered portion to be formed when the edge is chamfered, and the number of teeth Zw, A rotation surface setting step involves setting the shape of a virtual rotation surface that rotates around the tool axis in the direction of rotation of the chamfering tool, A condition setting step in which the initial phase of the rotating surface, the machining position, an arbitrary integer K, and the number of machining blades Zt set in the rotating surface setting step are set, Based on the settings of the condition setting step and the gear setting step, an acquisition step is performed to acquire the intersection lines of the rotation surface and the chamfered portion at each phase when the gear is rotated K・Zt / Zw around the rotation axis while rotating the rotation surface once around the tool axis from the initial phase in the machining position, A method for manufacturing a chamfering tool, comprising: a forming step of forming the chamfering tool by using a line tangent to a plurality of intersection lines obtained in the acquisition step as the machining blade, and using the rotating surface on the tool axis side of the machining blade as the rake face.

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