Gear chamfering process, chamfering tool and chamfering tool manufacturing process

Abstract

A gear chamfering method is provided that enables the chamfering of an edge section in an axial direction of the tooth flank of each tooth of a gear in a short time. The gear chamfering method comprises a chamfering step of chamfering edge sections 15b and 15c of a plurality of teeth 12 of a gear 10 by a chamfering tool 20 with a machining edge 24. In a case where any integer is represented by K, the number of teeth 12 is represented by Zw, and the number of machining edges 24 is represented by Zt, the chamfering step involves performing KT / Zw rotations of the gear 10 about a rotational axis C1 for each rotation of the chamfering tool 20 about a tool axis C2 in a machining orientation where the tool axis C2 is not parallel to the rotational axis C1.Consequently, the processing edge 24 is sequentially brought into contact with a majority of the edge sections 15b and 15c in order to chamfer the edge sections 15b and 15c.

Description

TECHNICAL AREA

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

[0002] A method is known in which, while a gear is being rotated, a chamfering tool is rotated synchronously about a tool axis parallel to an axis of rotation of the gear in order to chamfer the upper teeth of the gear (Patent Publication 1). The chamfering tool has a plurality of tool teeth about the tool axis, and the upper teeth of the tool teeth are brought into contact with the upper teeth of the gear in order to chamfer the upper teeth of the gear. PRINT OF THE STATEMENT OF THE TECHNICAL PATENT PRINT

[0003] Patent document 1: Japanese patent application with publication (kokai) no. H4-146022 SUMMARY OF THE INVENTION: THE PROBLEM TO BE SOLVED BY THE INVENTION

[0004] The chamfering tool disclosed in patent document 1, however, is used for chamfering the upper tooth webs of a gear and has difficulties when chamfering edge sections in an axial direction of the tooth flanks of each tooth of the gear. Although a method is known in which such edge sections are chamfered successively with the end-cutting edge of an end mill, this method has the problem that the machining time becomes long.

[0005] The present invention was made to solve the aforementioned problems, and one object of the present invention is to provide a gear chamfering method, a chamfering tool and a chamfering tool manufacturing method that makes it possible to chamfer an edge section in an axial direction of a tooth flank of each tooth of a gear in a short time. MEANS TO SOLVE THE PROBLEM

[0006] To solve this problem, a gear chamfering method of the present invention comprises a chamfering step of chamfering a gear having a plurality of teeth formed around an axis of rotation by means of a chamfering tool configured to be rotated about a tool axis. Each of the plurality of teeth has a tooth flank as a surface oriented in a circumferential direction of the gear and a marginal section in an axial direction of the axis of rotation of the tooth flank. The chamfering tool has at least one machining edge formed about the tool axis in a shape corresponding to a shape of the marginal section. Any integer is represented by K, the number of teeth is represented by Zw, and the number of machining edges is represented by Zt.The chamfering step involves performing K·Zt / Zw rotations of the gear around the axis of rotation for each rotation of the chamfering tool around the tool axis in a machining orientation in which the tool axis is not set parallel to the axis of rotation, and sequentially bringing the machining edge into contact with a plurality of the edge sections in order to chamfer the edge sections. ADVANTAGEOUS EFFECTS OF THE INVENTION

[0007] The gear chamfering method according to claim 1 comprises a chamfering step of chamfering an edge section in an axial direction of a rotational axis of a tooth flank of any plurality of teeth of a gear by a chamfering tool having at least one machining edge formed about a tool axis. The chamfering in the chamfering step is performed in a machining orientation in which the tool axis is not set parallel to the rotational axis. Consequently, the edge section of the gear can be chamfered while the chamfering tool and the gear are rotated synchronously.

[0008] If any integer is represented by K, the number of teeth by Zw, and the number of machining edges by Zt, then the synchronous rotation K·Zt / Zw above involves rotations of the gear about the axis of rotation for every rotation of the chamfering tool about the tool axis. This synchronous rotation brings the machining edge, with a shape corresponding to a shape of the edge section, into sequential contact with a plurality of the edge sections to chamfer them. Therefore, the gear's edge sections can be chamfered in a short time.

[0009] A gear chamfering method according to claim 2 has the following advantageous effect in addition to the advantageous effects of the gear chamfering method according to claim 1. The number Zt of machining edges is two or more. The chamfering step involves bringing different machining edges into contact with the respective upper tooth web and tooth root surfaces of one of the edge sections in order to chamfer the upper tooth web and tooth root surfaces. Thus, the shape of the machining edge to be brought into contact with the upper tooth web surface of the edge section and the shape of the machining edge to be brought into contact with the tooth root surface of the edge section can be designed independently of one another, or the machining orientations in which the respective machining edges are brought into contact, or the like, can be set differently.This allows the size and angle of the chamfer to be provided to the marginal section between the upper tooth ridge side and the tooth root surface to be adjusted (e.g., to be adjusted evenly).

[0010] A gear chamfering method according to claim 3 has the following advantageous effect in addition to the advantageous effects of the gear chamfering method according to claim 1. The machining orientation corresponds to a state in which the tool axis, located on a first imaginary plane containing the axis of rotation, is displaced from the first imaginary plane in a direction perpendicular to the first imaginary plane. In this case, one or more of the edge sections of the plurality of teeth become nearly parallel to the tool axis. The chamfering step involves bringing the machining edge into contact with each of the edge sections that have become nearly parallel to the tool axis in order to chamfer the edge section. Consequently, the entirety of this edge section can be chamfered by the machining edge in a short time.As a result, the upper tooth ridge side and the tooth root surface side of the edge section are chamfered equally by the machining edge, allowing the size and angle of the chamfer to be provided to the edge section to be set uniformly over the entire edge section.

[0011] A gear chamfering method according to claim 4 has the following advantageous effect in addition to the advantageous effects of the gear chamfering method according to claim 1. The machining orientation corresponds to a state in which the tool axis is inclined from a second imaginary plane perpendicular to the axis of rotation. Consequently, the rotation of the tool about the tool axis during the chamfering step causes the machining edge to tilt accordingly in the circumferential direction of the gear when viewed in the axial direction of the axis of rotation. This tilt can cause the machining edge and the edge portion of any one of the teeth to become nearly parallel to each other. When both the machining edge and the edge portion become nearly parallel to each other, the machining edge is brought into contact with the edge portion to chamfer the edge portion.Consequently, the entire edge section can be chamfered by the machining edge in a short time. As a result, the upper tooth ridge side and the tooth root surface side of the edge section are chamfered equally by the machining edge, allowing the size and angle of the chamfer to be applied to the edge section to be set uniformly across the entire edge section.

[0012] A gear chamfering method according to claim 5 has the following advantageous effect in addition to the advantageous effects of the gear chamfering method according to claim 1. The chamfering tool has a rake face extending from the machining edge to the tool axis side and facing forward in a direction of rotation of the chamfering tool. The rake face and the machining edge are located on a third imaginary plane that includes the tool axis, whereby the phase of the machining edge to be rotated about the tool axis can be easily identified from the orientation of the rake face. Therefore, an initial phase of the machining edge at the beginning of the rotation of the machining edge about the tool axis in the chamfering step is determined based on the rake face, thus making the initial phase easy to determine.

[0013] A gear chamfering tool according to claim 6 is used for the gear chamfering method according to claim 5. The machining edge is a section with a radius smaller than the maximum radius of the chamfering tool and is formed at a front end face in an axial direction of the chamfering tool. The rake face extends to one side opposite the front end face of the chamfering tool beyond the position where the machining edge is formed. Consequently, the rake face can be broadened to serve as a basis for determining the initial phase of the machining edge. Therefore, the orientation or similar characteristics of the rake face can be easily detected by a sensor or the like, thus facilitating the determination of the initial phase.

[0014] A gear chamfering tool according to claim 7 is used for the gear chamfering method according to any one of claims 1 to 4. The chamfering tool includes a cutting element formed around the tool axis. The cutting element has: a front rake face facing forward in a direction of rotation of the chamfering tool; a rear rake face facing backward in the direction of rotation of the chamfering tool; and a connecting surface connecting radially outer boundaries of the front rake face and the rear rake face. A line of intersection between the connecting surface and the front rake face and a line of intersection between the connecting surface and the rear rake face form a pair of machining edges configured to chamfer respective edge portions of the gear.

[0015] This allows, during a single rotation of the chamfering tool, one of the adjacent edge sections to be chamfered circumferentially by the machining edge on the front rake face side, and the other adjacent edge section to be chamfered by the machining edge on the rear rake face side. In this case, compared to a situation where both adjacent edge sections are chamfered by the same machining edge, the machining edges can be formed into shapes suitable for the respective edge sections, thus allowing easy adjustment of the chamfer size and angle to be applied to each edge section.

[0016] A chamfering tool manufacturing method according to claim 8 is a method for manufacturing the chamfering tool that is to be used for the gear chamfering method according to any one of claims 1 to 5. The chamfering tool has: at least one machining edge formed around the tool axis; and a rake face extending from the machining edge to the side of the tool axis and facing forward in a direction of rotation of the chamfering tool.

[0017] A gear setting step involves setting the shape of the gear, including the number Zw of teeth and the shape of a chamfer section to be formed by chamfering each of the gear's edge sections. A rotary plane setting step involves setting the shape of an imaginary plane of rotation to be rotated about the tool axis, with the imaginary plane of rotation aligned in the direction of rotation of the chamfering tool. A condition setting step involves setting an initial phase of the rotary plane, as set in the rotary plane setting step, the machining orientation in the chamfering step, any integer K, and the number Zt of machining edges.

[0018] A subsequent acquisition step involves capturing an intersection line between the plane of rotation and the chamfer section in each of the phases obtained when the K·Zt / Zw rotations of the gear about the axis of rotation are performed during a rotation of the plane of rotation about the tool axis from the initial phase in the machining orientation, based on the settings in the condition setting step and the gear setting step. A training step involves setting, as the machining edge, a line in contact with a plurality of the intersection lines captured in the acquisition step, and setting, as the rake face, the plane of rotation closer to the tool axis than the machining edge to train the chamfer tool.Therefore, the shape of a chamfer section that is actually to be formed by the gear chamfering method according to claim 1 using this chamfering tool can be made similar to the shape of the chamfer section that is set in the gear setting step. BRIEF DESCRIPTION OF THE DRAWINGS Fig. Figure 1 is a perspective view of a gear and a chamfering tool, showing a gear chamfering method in a first embodiment. Fig. 2(a) is a front view of the chamfering tool and Fig. 2(b) is a view from below of the chamfering tool, seen in the direction indicated by arrow IIb in Fig. 2(a) indicated direction. Fig. 3(a) is a partially enlarged front view of the gear, seen from the perspective indicated by arrow IIIa in Fig. 1 indicated direction, and Fig. 3(b) is a partially enlarged top view of the gear, seen in the direction indicated by arrow IIIb in Fig. 3(a) indicated direction. Fig. Figure 4 is a schematic representation showing part of a chamfering tool manufacturing process. Fig. Figure 5(a) is a front view of a chamfering tool to be used for a gear chamfering process in a second embodiment, and Fig. 5(b) is a bottom view of the chamfering tool, seen in the direction indicated by arrow Vb in Fig. 5(a) indicated direction. Fig. Figure 6 is a schematic representation showing a gear chamfering method in a third embodiment. Fig. Figure 7 is a schematic representation showing a gear chamfering method in a fourth embodiment. Fig. Figure 8(a) is a front view of a chamfering tool to be used for a gear chamfering process in a fifth embodiment, Fig. 8(b) is a side view of the chamfering tool, seen in the direction indicated by arrow VIIIb in Fig. 8(a) specified direction, and Fig. 8(c) is a bottom view of the chamfering tool, seen in the direction indicated by arrow VIIIc in Fig. 8(a) indicated direction. EXECUTIONAL FORMS FOR IMPLEMENTING THE INVENTION

[0019] Preferred embodiments are described below with reference to the accompanying drawings. Fig. Figure 1 is a perspective view of a gear 10 and a chamfering tool 20 (hereinafter referred to as "tool 20"), which show a method for chamfering the gear 10 in a first embodiment. Fig. 2(a) is a front view of tool 20. Fig. 2(b) is a bottom view of tool 20, seen in the direction indicated by arrow IIb in Fig. 2(a) indicated direction. Fig. Figure 1 does not show the lower half of gear 10. Fig. 1 and Fig. 2(a) do not show a rear end (top side) of tool 20.

[0020] As in Fig. As shown in Figure 1, the gear 10 is an external gear comprising: a column-shaped portion with a center on an axis of rotation C1; and a plurality of (in the present embodiment, 18) teeth 12 projecting outwards in a radial direction from an outer circumferential surface of the column-shaped portion. The plurality of teeth 12 are provided at regular intervals around the axis of rotation C1 and have identical shapes. The plurality of teeth 12 extend parallel to the axis of rotation C1.

[0021] The outer circumferential surface of the columnar part of the gear 10 has surfaces between the plurality of teeth 12, wherein the surfaces are tooth root surfaces 13. Each of the teeth 12 has: an upper surface in the radial direction, wherein the upper surface is an upper tooth web surface 12a; and a pair of surfaces connecting the upper tooth web 12a and the corresponding tooth root surfaces 13 and oriented in a circumferential direction, wherein the pair of surfaces are tooth flanks 12b and 12c. In a case where the right side in Fig. If the front of the gear 10 is defined as the front side of the gear 10 in an axial direction (arrow-Y direction) of the axis of rotation C1, the tooth flank 12b is oriented clockwise when viewed from the front side and the tooth flank 12c is oriented counterclockwise.

[0022] A line of intersection between the upper tooth ridge surface 12a and each of the end faces 14 in the axial direction of the axis of rotation C1 of the gear 10 is a boundary section 15a. A line of intersection between the end face 14 and the tooth flank 12b is a boundary section 15b. A line of intersection between the end face 14 and the tooth flank 12c is a boundary section 15c. A line of intersection between the end face 14 and each of the tooth root faces 13 is a boundary section 15d.

[0023] The majority of teeth 12 of such a gear 10 are formed by a gear cutting tool or a rolling device (not shown). Subsequently, a majority of the edge sections 15b to 15d are chamfered by the tool 20. Finally, the edge sections 15a are chamfered by another tool (not shown).

[0024] As in Fig. 2(a) and Fig. As shown in 2(b), the tool 20 comprises: a shaft 21 with a columnar shape and with a center on a tool axis C2; a body 22 which is attached at a front end (on the underside in Fig. 2(a)) is provided in an axial direction of the shaft 21; and a cutting part 23 projects in a radial direction from the body 22. The body 22 has such a shape that it tapers in the axial direction at a position further away from the shaft 21.

[0025] The shaft 21 has a rear end (the upper side in Fig. 2(a)) opposite the body 22 in the axial direction. The rear end is held by a machine tool, such as a multi-purpose processing machine. A drive force is transmitted from the machine tool to rotate the tool 20 about the tool axis C2. By rotating the tool 20, the edge sections 15b to 15d of the gear 10 are chamfered by the cutting element 23. A direction of rotation Rt of the tool 20 at the time of chamfering by the cutting element 23 is a clockwise direction when viewed from the front end in the Fig. 2(b) is considered in the axial direction shown.

[0026] The cutting element 23 is a section that projects outwards in the radial direction from an outer circumferential surface of the body 22, and in the present embodiment, only one such cutting element 23 is formed around the tool axis C2. The cutting element 23 has: a machining edge 24 for chamfering the edge sections 15b to 15d; a rake face 25 extending from the machining edge 24 to the side of the tool axis C2; and a flank surface 26 extending rearwards from the machining edge 24 in the direction of rotation Rt.

[0027] The machining edge 24 is a cutting edge formed from a front end to a rear end in the axial direction of the tool 20 by a line of intersection between the rake face 25 and the flank face 26. The shape of the machining edge 24 is determined according to the shapes of the edge sections 15b to 15d that are to be chamfered. In particular, the shape of the machining edge 24 extends from the front end in the axial direction of the tool 20 perpendicular to the tool axis C2 and is then curved to form a projection, a recess, and a projection in that order as it extends to the rear end face.

[0028] The machining edge 24 is a section that is smaller than the maximum radius of the tool 20 (shank 21). That is, the machining edge 24 is a section that is closer to the front end than an imaginary line L in Fig. 2(a). A section of the machining edge 24 near the imaginary line L and a linear section adjacent to the machining edge 24 and extending beyond the imaginary line L to the rear end face do not chamfer the edge sections 15b to 15d.

[0029] The rake face 25 is a surface for removing chips generated during chamfering by the machining edge 24 and faces forward in the direction of rotation Rt in the cutting section 23. The rake face 25 lies on an imaginary plane Pr, which includes the tool axis C2, and extends beyond the imaginary line L to the rear end. The shank 21 has a spirally shaped feed hole 22a with a lower end that opens towards the rake face 25. Through the feed hole 22a, cutting fluid is supplied to the rake face 25 during chamfering (cutting) by the tool 20, thereby cooling, lubricating, and cleaning the chamfered section.

[0030] The flank surface 26 is a surface for preventing further contact between the tool 20 and the section chamfered by the machining edge 24. The flank surface 26 is further back towards the side of the tool axis C2 at a position that is farther from the machining edge 24 in a circumferential direction.

[0031] To manufacture the tool 20, a columnar alloy blank, used to assemble the shank 21, is ground to cut the body 22, the rake face 25, and the flank face 26. Each of the rake face 25 and the flank face 26 formed by this grinding preferably has a surface roughness Rz (roughness at maximum height) of 1.6 or less. In this case, it is less likely that a burr will be generated during chamfering by the tool 20.

[0032] Next, a method for chamfering the gear 10 using the tool 20 will be described in detail with reference to Fig. 1, Fig. 3(a) and Fig. 3(b) described. Although a case in which the boundary sections 15b to 15d on the right-hand side in Fig. 1. Chamfered by tool 20, as described below, the same applies to a case in which the edge sections 15b to 15d on the left side are chamfered. Fig. 1. Beveled.

[0033] Fig. 3(a) is a partially enlarged front view of gear 10, seen from the perspective indicated by arrow IIIa in Fig. 1 specified direction (the axial direction of the axis of rotation C1). Fig. 3(b) is a partially enlarged top view of gear 10, seen in the direction indicated by arrow IIIb in Fig. 3(a) specified direction (radial direction).

[0034] To chamfer the edge sections 15b to 15d of the gear 10 using the tool 20, a machining orientation of the tool 20 relative to the gear 10 is first determined (preparation step). Then, the tool 20 is rotated in this machining orientation in the direction Rt about the tool axis C2, while the gear 10 is rotated in a direction Rw about the axis of rotation C1, thereby bringing the machining edge 24 into sequential contact with the majority of the edge sections 15b to 15d (chamfering step). The direction of rotation Rw in the present embodiment is counterclockwise from the tooth flank 12c to the tooth flank 12b.

[0035] The machining orientation in the present embodiment corresponds to a state in which the arrangement is such that: the axis of rotation C1 and the tool axis C2 are orthogonal to each other; and the front end of the tool 20 comes into contact with one of the lower toothed ridge surfaces 13 when viewed in the axial direction of the axis of rotation C1. Since the axis of rotation C1 and the tool axis C2 are orthogonal to each other, the tool axis C2 lies on a first imaginary plane P1, which includes the axis of rotation C1, and lies on a second imaginary plane P2 perpendicular to the axis of rotation C1. Fig. 1. The axial direction of the rotation axis C1 is given as the arrow-Y direction, the axial direction of the tool axis C2 is given as an arrow-Z direction, and a direction perpendicular to the rotation axis C1 and the tool axis C2 is given as an arrow-X direction.

[0036] The chamfering step involves performing K·Zt / Zw rotations of the gear 10 for each rotation of the tool 20. "K" represents any integer and is set to 1 in this embodiment. "Zt" represents the number of machining edges 24 of the tool 20 and is 1 in this embodiment. "Zw" represents the number of teeth 12 of the gear 10 and is 18 in this embodiment. That is, the chamfering step in this embodiment involves performing 1 / 18 rotations of the gear 10 for each rotation of the tool 20. The period of one rotation of the tool 20 is one cycle of the chamfering step.

[0037] Fig. 3(a) and Fig. Figure 3(b) shows the contact positions A to E between the edge sections 15b to 15d and the machining edge 24 during one cycle. Contact position A is a position where the machining edge 24 is brought into contact with the center in the circumferential direction of the edge section 15d. Contact position B is a position where the machining edge 24 is brought into contact with the edge section 15b. Contact position C is a position that is higher (closer to the upper tooth ridge surface 12a) than contact position B and where the machining edge 24 is brought into contact with the edge section 15b. Contact position D is a position that is at the same height as contact position B and where the machining edge 24 is brought into contact with the edge section 15c.The contact position E is a position that is at the same height as the height of the contact position C and at which the machining edge 24 is brought into contact with the edge section 15c.

[0038] Furthermore, in Fig. 3(b) a position of the tool axis C2 corresponding to the contact position A is specified as an axial position C2A. Likewise, in Fig. 3(b) Positions of the tool axis C2 corresponding to the respective contact positions B to E, each specified as axial positions C2B to C2E. Furthermore, in Fig. 3(b) Positions of the rake surface 25 corresponding to the respective contact positions A to E are indicated by alternating long and short dashed lines.

[0039] Additionally, in Fig. 3(b) The shape of a chamfer section 16d, formed by chamfering the edge section 15d by the machining edge 24, is indicated by a dashed line. Furthermore, in Fig. 3(b) The shapes, near contact positions B and C, of ​​chamfer sections 16b formed by chamfering the edge section 15b by the machining edge 24 are indicated by dashed lines. Likewise, the shapes, near contact positions D and E, of chamfer sections 16c formed by chamfering the edge section 15c by the machining edge 24 are indicated by dashed lines.

[0040] According to Fig. 3(a) and Fig. 3(b) The edge sections 15b to 15d are continuously chamfered during the single cycle of the chamfering step, such that the machining edge 24 passes through the contact positions E, D, A, B, and C in that order. With respect to this single cycle, when the tool 20 is moved relative to the gear 10, the tool 20 is rotated in the direction of rotation Rt, while the position of the tool axis C2 is shifted from the axial position C2E to the axial position C2C in a direction opposite to the direction of rotation Rw, as shown in Fig. 3(b) shown.

[0041] At contact position A, the tool axis C2 (axial position C2A) and the machining edge 24 are arranged on the first imaginary plane P1, which runs through the center in the circumferential direction of the edge section 15d. Therefore, the motion during the synchronous rotation of the tool 20 relative to the gear 10 is symmetrical between both sides of the first imaginary plane P1. Consequently, the chamfer sections 16b to 16d can be designed to be symmetrical about contact position A between both sides in the circumferential direction of the gear 10.

[0042] The preparatory step involves defining an initial phase of the machining edge 24 such that the tool axis C2 and the machining edge 24 are arranged on the first imaginary plane P1, which passes through the center in the circumferential direction of the edge section 15d at the contact position A in the chamfering step. The initial phase of the machining edge 24 is a position of the machining edge 24 with respect to the tool axis C2 and the gear 10 at the beginning of the rotation of the tool 20 (machining edge 24). By defining the initial phase in this way, the chamfer sections 16b to 16d can be designed to be symmetrical about the contact position A, as described above.

[0043] The initial phase can correspond, in particular, to the following: a state in which the tool axis C2 and the machining edge 24 are arranged on the first imaginary plane P1 mentioned above; or a state in which the gear 10 and the tool 20 are rotated synchronously from the aforementioned state, as in the chamfering step. For example, the initial phase can correspond to the positional relationship between the tool axis C2, the machining edge 24, and the gear 10 at one of the contact positions B to E. Alternatively, the initial phase can correspond to a state in which the gear 10 is rotated synchronously while the tool 20 is rotated 90 degrees or 180 degrees from the state in which contact position A is assumed.

[0044] In a case where the machining edge 24 and the gear 10 interfere with each other in the initial phase, it is preferred that: the tool 20 is positioned in advance in the axial direction of the axis of rotation C1 or in the radial direction away from the gear 10; and the tool 20 is positioned close to the gear 10 during the chamfering step. Consequently, the machining edge 24 gradually and deeply cuts the edge sections 15b to 15d, thereby suppressing chips or the like from the machining edge 24 and the edge sections 15b to 15d.

[0045] In addition, as referenced in Fig. As described in 2(b), the machining edge 24 and the rake face 25 are located on the imaginary plane Pr, which includes the tool axis C2. This allows the phase of the machining edge 24, which is to be rotated about the tool axis C2, to be easily identified from the orientation of the rake face 25. Therefore, the preparation step involves determining the initial phase of the machining edge 24 based on the rake face 25, thus making the initial phase easy to determine.

[0046] Furthermore, as with reference to Fig. As described in 2(a), the rake face 25 extends beyond the imaginary line L (machining edge 24) to the rear end face. Consequently, the rake face 25 can be broadened to serve as a basis for determining the initial phase of the machining edge 24. Therefore, the orientation or similar of the rake face 25 can be easily detected by a sensor or the like, thus facilitating the determination of the initial phase.

[0047] It refers to Fig. 3(a) and Fig. 3(b) described. The chamfer section 16d is formed by chamfering substantially the entirety of the edge section 15d by the projection of the machining edge 24 that is closest to its front end. Therefore, the shape and angle of the chamfer section 16d can be set approximately uniformly over its entire circumference.

[0048] Here, in a case where the end surface 14 of the gear 10 and the chamfer sections 16b to 16d are parallel to each other, the angles of the chamfer sections 16b to 16d are considered to be 0 degrees. At each of the contact positions B to E, the inclination angle of the rake face 25 (machining edge 24) with respect to the end surface 14 is approximately equal to the angle of the corresponding chamfer sections 16b and 16c. Therefore, if the timing of the formation of the chamfer sections 16b or 16c by the machining edge 24 differs in the chamfering step between contact position B or D and contact position C or E, the inclination angle of the rake face 25 varies, and the angles of the chamfer sections 16b or 16c differ from each other according to the difference in this timing.In the third and fourth embodiments described later, a method is described to make it less likely that the angles of the chamfer sections 16b or 16c will differ from each other.

[0049] As described above, the chamfering step in the present embodiment involves repeating a cycle in which the edge sections 15c, 15d, and 15b are continuously chamfered in this sequence by the machining edge 24 through synchronous rotation of the gear 10 and the tool 20. This chamfering step allows the edge sections 15b to 15d of the majority of teeth 12 to be chamfered sequentially. Therefore, the edge sections 15b to 15d of the gear 10 can be chamfered in a short time.

[0050] The machining edge 24 used in the chamfering step has a shape corresponding to the shapes of the edge sections 15b to 15d, as described above. A method for manufacturing the tool 20, which includes a method for shaping this machining edge 24, is described with reference to Fig. 1 and Fig. 4 described. Fig. Figure 4 is a schematic representation showing part of the process for manufacturing tool 20.

[0051] First, the shape of the gear 10, which is to be chamfered by the tool 20, is set (gear setting step). The shape of the gear 10 includes the dimensions of the gear 10, the number of teeth 12, and the shapes of the chamfer sections 16b to 16d, which are to be formed by chamfering the edge sections 15b to 15d.

[0052] Next, the shape of an imaginary plane of rotation, which is to be rotated about the tool axis C2, is set, the imaginary plane of rotation being oriented in the direction of rotation Rt of the tool 20 (plane of rotation setting step). The imaginary plane of rotation is a plane corresponding to the rake face 25. In the present embodiment, the imaginary plane of rotation set in the plane of rotation setting step is the imaginary plane Pr, which includes the tool axis C2.

[0053] Next, an initial phase of the imaginary plane Pr, set in the rotary plane setting step, the machining orientation in the chamfering step in which the designed tool 20 is to be used, the arbitrary integer K, and the number Zt of the machining edges 24 of the tool 20 are set (condition setting step). The machining orientation, the integer K, and the number Zt in the present embodiment are as explained above in the description of the chamfering step. The initial phase of the imaginary plane Pr is identical to the initial phase of the machining edge 24 (clamping surface 25) in the chamfering step above.

[0054] Next, in the same manner as in the chamfering step, the K·Zt / Zw rotations of the gear 10 about the axis of rotation C1 during a rotation of the imaginary plane Pr about the tool axis C2 from the initial phase in the machining orientation are performed based on the settings in the condition setting step and the gear setting step (capture step). The capture step involves capturing intersection lines 28 between the imaginary plane Pr and the chamfer sections 16b to 16d in each of the phases obtained when the synchronous rotation of the gear 10 and the imaginary plane Pr is performed.

[0055] In Fig. Figure 4 shows some of the majority of the section lines 28 that were captured in the acquisition step, in a state where they are arranged on the imaginary plane Pr. Furthermore, in Fig. 4 The number, sizes, orientations, positions and the like of the cutting lines 28 are shown schematically to facilitate understanding of the procedure for shaping the form of the machining edge 24.

[0056] A training step following the acquisition step involves setting the machining edge 24, a line (envelope) in contact with the majority of cutting lines 28 on one side opposite the tool axis C2, and setting the rake face 25, the imaginary plane Pr, closer to the tool axis C2 than the machining edge 24, to form (shape) the tool 20. Consequently, the machining edge 24 of the tool 20, formed in the training step, can actually chamfer the edge sections 15b to 15d at positions close to the chamfer sections 16b to 16d set in the gear setting step. Therefore, the shapes of the chamfer sections 16b to 16d that are actually to be formed by chamfering can be made similar to the shapes of the chamfer sections 16b to 16d set in the gear setting step.

[0057] Furthermore, after the training step, a comparison between the shapes of the chamfer sections 16b to 16d actually formed by the tool 20 and the shapes of the chamfer sections 16b to 16d set in the gear setting step (determination step) can determine whether the shape of the tool 20 needs to be readjusted. The shapes of the chamfer sections 16b to 16d actually formed by the tool 20 can be calculated on a PC based on the shape of the machining edge 24 determined in the training step.

[0058] The determination step includes, for example, determining that the shape of the tool 20 does not need to be readjusted if the difference between the angles of the actual chamfer sections 16b to 16d and the angles of the set chamfer sections 16b to 16d is within a range of -10 degrees to +10 degrees. Conversely, the determination step also includes determining that the shape of the tool 20 must be readjusted if the difference lies outside this range. However, the procedure for determining the need to readjust the shape of the tool 20 can be modified as required, according to the shape of the gear 10, a machining condition, and the like.

[0059] If the determination that the shape of tool 20 needs to be readjusted is made in the determination step, at least one of the settings in the rotary plane setting step and the condition setting step is changed (modification step). After the modification step, the acquisition step and the training step are repeated to train (shape) tool 20. Furthermore, the steps from the determination step to the training step can be repeated as needed to complete tool 20. As a result of these steps, the shapes of the chamfer sections 16b to 16d that are actually to be formed by tool 20 can be made more similar to the shapes of the chamfer sections 16b to 16d that were set in the gear setting step.

[0060] Next, a second embodiment will be described with reference to Fig. 5(a) and Fig. 5(b) described. In the first embodiment, a tool 20 with a machining edge 24 was described. Meanwhile, in the second embodiment, a chamfering tool 30 (hereinafter referred to as "tool 30") with two machining edges 32 and 36 is described. The same components as in the first embodiment are designated by the same reference numerals, and a description thereof is omitted.

[0061] Fig. Figure 5(a) is a front view of the chamfering tool 30, which is to be used for a method for chamfering the gear 10 in the second embodiment. Fig. 5(b) is a bottom view of the chamfering tool 30, seen in the direction indicated by arrow Vb in Fig. 5(a) indicated direction. Fig. 5(a) does not show the rear end (top side) of tool 30.

[0062] The tool 30 is used for chamfering the same gear 10 as in the first embodiment. The tool 30 comprises: the shank 21; the body 22; and two cutting elements 31 and 35, which are formed around the tool axis C2 and project radially from the outer circumferential surface of the body 22.

[0063] The two cutting parts 31 and 35 are arranged 180 degrees apart around the tool axis C2. The cutting part 31 has: a machining edge 32 for chamfering the edge sections 15b to 15d of the gear 10; a rake face 33 extending from the machining edge 32 to the side of the tool axis C2; and a flank surface 34 extending rearward from the machining edge 32 in the direction of rotation Rt. Similarly, the cutting part 35 has a machining edge 36, a rake face 37, and a flank surface 38. The rake faces 33 and 37 and the flank surfaces 34 and 38 each have the same functions as those of the rake face 25 and the flank surface 26 in the first embodiment, and therefore their description is omitted.

[0064] Machining edge 32 is a cutting edge formed from the front end to the rear end in the axial direction of the tool 30 by a line of intersection between the rake face 33 and the flank face 34. Machining edge 36 is a cutting edge formed from the front end to the rear end in the axial direction of the tool 30 by a line of intersection between the rake face 37 and the flank face 38. Each of the machining edges 32 and 36 lies on the imaginary plane Pr, which includes the tool axis C2.

[0065] In Fig. 5(a), which is a front view of the rake face 33, the machining edge 36, which has overlapped with the machining edge 32 as a result of rotating the machining edge 36 by 180 degrees about the tool axis C2, is indicated by one alternating long and two short dashed lines. According to Fig. 5(a) the machining edge 32 is located on the front end of the tool 30 further out in the radial direction than the machining edge 36. Meanwhile, the machining edge 36 is located on the rear end of the tool 30 further out in the radial direction than the machining edge 32.

[0066] From the machining edges 32 and 36, sections located relatively far out in the radial direction primarily chamfer the edge sections 15b to 15d to form the chamfer sections 16b to 16d. The shapes of the outer sections are formed by the same method as that used for machining edge 24 in the first embodiment. Meanwhile, sections located relatively far in the radial direction from machining edges 32 and 36 have shapes designed with consideration for strength, ease of manufacture, and the like.

[0067] A chamfering method in the second embodiment is described primarily with regard to its differences from the chamfering method in the first embodiment. A chamfering step in which the tool 30 is used in the second embodiment involves chamfering continuous edge sections 15b to 15d by the machining edge 32 during one half of a rotation of the tool 30, first in a case where the arbitrary integer K is set to 1. The chamfering step further involves the subsequent chamfering of continuous edge sections 15b to 15d at positions adjacent to the chamfered edge sections 15b to 15d in the circumferential direction, the subsequent chamfering being performed by the machining edge 36 during the other half of the rotation of the tool 30.

[0068] On the one hand, in a case where the number of teeth 12 of the gear 10 is odd, edge sections 15b to 15d, which are chamfered by the machining edge 32 during a first rotation of the gear 10, are chamfered by the machining edge 36 during a second rotation of the gear 10. At this point, the section of the machining edge 36 that is located further out in the radial direction than the machining edge 32 is brought into contact with the edge sections 15b to 15d in order to chamfer them, and the other edge sections are not chamfered.

[0069] Similarly, edge sections 15b to 15d, which are chamfered by the machining edge 36 during the first rotation of the gear 10, are chamfered by the machining edge 32 during the second rotation of the gear 10. At this point, the section of the machining edge 32 that is located further out in the radial direction than the machining edge 36 is brought into contact with the edge sections 15b to 15d in order to chamfer them, and the other edge sections are not chamfered.

[0070] On the other hand, if the number of teeth 12 of gear 10 is even, each of the machining edges 32 and 36 will continuously chamfer the same edge sections 15b to 15d. Therefore, the synchronous rotation of gear 10 and tool 30 is stopped during one or more rotations of gear 10 during the chamfering step. Then, 1 / 2 of a rotation of gear 10 or 1 / 2 of a rotation of tool 30 is performed to change the phase. Finally, the synchronous rotation of gear 10 and tool 30 is restarted. After this restart, the edge sections 15b to 15d are chamfered by the machining edge 32 or 36, which differs from the machining edge used before the restart, as in the second rotation, which is carried out in the case where the number of teeth 12 is an odd number.

[0071] In the case where the number of teeth Zw is an even number, the machining orientation or the like can be set to differ between before and after restarting the synchronous rotation during the chamfering step. Consequently, the sizes and angles of the chamfers to be provided to edge sections 15b to 15d can be set to differ between the first and second rotations.

[0072] Furthermore, in any case, the sides of the upper tooth ridge surface 12a of the marginal sections 15b to 15d of one of the teeth 12 can be chamfered by the machining edge 36, and the sides of the tooth root surface 13 of these marginal sections 15b to 15d can be chamfered by the machining edge 32. Thus, the shapes of the machining edges 32 and 36 on the sections thereof for chamfering the marginal sections 15b to 15d can be adjusted independently of each other. This allows the sizes and angles of the chamfers to be provided to the marginal sections 15b to 15d between the sides of the upper tooth ridge surface 12a and the sides of the tooth root surface 13 to be adjusted (e.g., to be uniformly adjusted).

[0073] Next, a third embodiment will be described with reference to Fig. 6. In the first embodiment, a case was described in which the gear 10 is chamfered by the tool 20 in a machining orientation where the axis of rotation C1 and the tool axis C2 are orthogonal to each other. In the third embodiment, a case is described in which the gear 10 is chamfered by a chamfering tool 40 (hereinafter referred to as "tool 40") in a machining orientation where the tool axis C2 is inclined in the arrow-Y direction from the machining orientation in the first embodiment. The same components as in the first embodiment are designated by the same reference numerals, and a description of them is omitted.

[0074] Fig. Figure 6 is a schematic representation showing a method for chamfering the gear 10 in the third embodiment. Fig. Figure 6 shows a pair of tooth flanks 12b and 12c, which are parts of the gear 10 in the circumferential direction and are opposite each other in the circumferential direction. The in Fig. 6 The gear 10 shown is in a state in which the edge sections 15b to 15d are chamfered, so that the chamfer sections 16b to 16d are formed. Fig. Figure 6 schematically shows only the tool axis C2 and a machining edge 41 emerging from the tool 40 for chamfering the gear 10.

[0075] The machining edge 41 of the tool 40 is a cutting edge formed around the tool axis C2 from the front end to the rear end in the axial direction of the tool 40. The tool 40, which includes the machining edge 41, is formed in essentially the same way as the tool 20 in the first embodiment, except that the shape of a part of the tool 40 differs. The shape of the machining edge 41 is shaped by changing the machining orientation in the sensing step, as in the following third embodiment, in the same way as in the design method described in the first embodiment.

[0076] A chamfering process in the third embodiment is described mainly in terms of its differences from the chamfering process in the first embodiment. In a machining orientation in the third embodiment, the tool axis C2 is located on the first imaginary plane P1 (see Fig. 3(b)), which is a YZ plane that includes the axis of rotation C1 (see Fig. 1) Furthermore, this machining orientation corresponds to a state in which the tool axis C2 is tilted by an angle θ in the arrow-Y direction from the second imaginary plane P2 (see Fig. 3(b)) is inclined, which is an XZ-plane. In Fig. 6 is an imaginary line 42 extending parallel to the second imaginary plane P2 from the front end along the tool axis C2, indicated by one alternating long and two short dashed lines. The angle between the imaginary line 42 and the tool axis C2 is the inclination angle θ.

[0077] When the chamfering step is performed in this machining orientation, the machining edge 41 is inclined in the circumferential direction of the gear 10 in conjunction with the rotation of the tool 40 when viewed in the arrow-Y direction (the axial direction of the axis of rotation C1). Consequently, the machining edge 41 and the edge sections 15b and 15c (sections where the chamfer sections 16b and 16c still need to be formed) of each of the teeth 12 can become nearly parallel to each other. When the machining edge 41 and the edge sections 15b and 15c become nearly parallel to each other by adjusting the inclination angle θ or the like, the machining edge 41 is brought into contact with the edge sections 15b and 15c to chamfer them. Consequently, the entirety of the edge sections 15b and 15c can be chamfered in a short time by the processing edge 41.As a result, the upper tooth ridge side and the tooth base surface side of each of the edge sections 15b and 15c are chamfered equally by the machining edge 41.

[0078] In particular, the inclination angle of the machining edge 41 with respect to the final surface 14, where the machining edge 41 is brought into contact with the edge sections 15b and 15c, can be determined as described with reference to Fig. The angles described in 3(b) are adjusted so that they are uniform between the upper tooth ridge face and the tooth root face. Therefore, the sizes and angles of the chamfers to be provided to the edge sections 15b and 15c by the machining edge 41 can be adjusted uniformly over the entirety of the edge sections 15b and 15c.

[0079] Next, a fourth embodiment will be described with reference to Fig. 7. In the first embodiment, a case was described in which the gear 10 is chamfered by the tool 20 in the machining orientation in which the axis of rotation C1 and the tool axis C2 are orthogonal to each other. In the fourth embodiment, a case is described in which the gear 10 is chamfered by a chamfering tool 50 (hereinafter referred to as "tool 50") in a machining orientation in which the tool axis C2 is shifted parallel to the machining orientation in the X-arrow direction from that in the first embodiment. The same components as in the first embodiment are designated by the same reference numerals, and a description of them is omitted.

[0080] Fig. Figure 7 is a schematic representation showing a method for chamfering the gear 10 in the fourth embodiment. Similar to Fig. 6 shows Fig. 7 a part of the gear 10 in the circumferential direction. The in Fig. 7 The gear 10 shown is in a state in which the edge sections 15b to 15d are chamfered, so that the chamfer sections 16b to 16d are formed. Fig. Figure 7 schematically shows only the tool axis C2 and a machining edge 51 emerging from the tool 50 for chamfering the gear 10.

[0081] The machining edge 51 of the tool 50 is a cutting edge formed around the tool axis C2 from the front end to the rear end in the axial direction of the tool 50. The tool 50, which includes the machining edge 51, is formed in essentially the same way as the tool 20 in the first embodiment, except that the shape of a part of the tool 50 differs. The shape of the machining edge 51 is shaped by changing the machining orientation in the sensing step, as in the following fourth embodiment, in the same way as in the design method described in the first embodiment.

[0082] A chamfering method in the fourth embodiment is described mainly in terms of its differences from the chamfering method in the first embodiment. A machining orientation in the fourth embodiment corresponds to a state in which: the tool axis C2 is parallel to the Z-direction of arrow; and the tool axis C2 is shifted parallel to the first imaginary plane P1 in the X-direction perpendicular to it from a position on the first imaginary plane P1 (see Fig. 3(b)).

[0083] In this machining orientation, one or more of the edge sections 15b and 15c (sections where the chamfer sections 16b and 16c still need to be formed) of the majority of teeth 12 are machined almost parallel to the tool axis C2. Fig. 7 In a case where the tool 50 is oriented downwards, the tool axis C2 and the edge section 15b (an edge of the tooth flank 12b) of a tooth 12 on the upper right side of the gear 10 are almost parallel to each other.

[0084] The chamfering step involves bringing the machining edge 51 into contact with the edge section 15b, which has become almost parallel to the tool axis C2, in order to chamfer the edge section 15b. Consequently, the entirety of this edge section 15b can be chamfered by the machining edge 51 in a short time. As a result, the upper tooth ridge side and the tooth root surface side of the edge section 15b are chamfered equally by the machining edge 51.

[0085] In particular, the inclination angle of the machining edge 51 with respect to the end surface 14, where the machining edge 51 is brought into contact with the edge section 15b, can be determined as described with reference to Fig. The angle described in 3(b) can be adjusted so that it is uniform between the upper tooth ridge face and the tooth root face. Therefore, the size and angle of the chamfer to be provided to the edge section 15b by the machining edge 51 can be adjusted uniformly over the entire edge section 15b.

[0086] After the edge section 15b has been chamfered, the chamfering step is performed, with the machining orientation being partially changed to also chamfer the edge section 15c. In a case where the tool 50 is oriented downwards, the tool axis C2 and the edge section 15b of a tooth 12 on the upper right side of the gear 10 become almost parallel to each other, as described above with reference to Fig. 7 described. In this case, the edge section 15c (an edge of the tooth flank 12c) of a tooth 12 on the upper left side of the gear 10 is also almost parallel to the tool axis C2.

[0087] Therefore, the chamfering step for edge section 15c involves adjusting the machining orientation (the position in the arrow-X direction) so that the machining edge 51 comes into contact with edge section 15c, which has become almost parallel to the tool axis C2, in order to chamfer the edge section 15c. As a result, the size and angle of the chamfer to be provided to edge section 15c by the machining edge 51 can be uniformly adjusted over the entirety of edge section 15c in the same way as when chamfering edge section 15b.

[0088] Next, a fifth embodiment will be described with reference to Fig. 8(a) to Fig. 8(c) described. In the first embodiment, a tool 20 with a cutting part 23 having a machining edge 24 was described. In the fifth embodiment, a chamfering tool 60 (hereinafter referred to as "tool 60") with a cutting part 61 having two machining edges 62 and 64 is described. The same components as in the first embodiment are designated by the same reference numerals, and a description thereof is omitted.

[0089] Fig. Figure 8(a) is a front view of the tool 60 which is to be used for a method for chamfering the gear 10 in the fifth embodiment. Fig. 8(b) is a side view of tool 60, seen in the direction indicated by arrow VIIIb in Fig. 8(a) indicated direction. Fig. 8(c) is a bottom view of tool 60, seen through arrow VIIIc in Fig. 8(a) indicated direction. Fig. 8(a) and Fig.Figure 8(b) does not show the rear end (top side) of tool 60.

[0090] The tool 60 is used for chamfering the same gear 10 as in the first embodiment. The tool 60 comprises: the shank 21 with a columnar shape and with a center on the tool axis C2; the body 22 with a columnar shape and provided at its front end in the axial direction of the shank 21; and a cutting element 61 that projects radially from the outer circumferential surface of the body 22.

[0091] The cutting element 61 comprises: a front rake face 63, which faces forward in the direction of rotation Rt; a rear rake face 65, which faces backward in the direction of rotation Rt; and a connecting surface 66, which connects the radially outer boundaries of the front rake face 63 and the rear rake face 65. A line of intersection between the front rake face 63 and the connecting surface 66 forms the machining edge 62. A line of intersection between the rear rake face 65 and the connecting surface 66 forms the machining edge 64. The machining edges 62 and 64 are cutting edges that extend from the front end to the rear end in the axial direction of the tool 60.

[0092] The front rake face 63 is a surface for removing chips produced during chamfering by the machining edge 62. The shank 21 has a spirally shaped feed hole 68 with a lower end that opens towards the front rake face 63. During chamfering, cutting fluid is supplied to the front rake face 63 through the feed hole 68 by the tool 60, thereby cooling, lubricating, and cleaning the chamfered section.

[0093] The rear rake face 65 is a surface for removing chips produced during chamfering by the machining edge 64. The shank 21 has a spirally shaped feed hole 69 with a lower end that opens towards the rear rake face 65. During chamfering by the tool 60, cutting fluid is supplied to the rear rake face 65 through the feed hole 69, thereby cooling, lubricating, and cleaning the chamfered section.

[0094] Since the front rake face 63 and the rear rake face 65 are oriented in opposite directions, the spirals of the feed hole 68 and the feed hole 69 for supplying cutting fluids to the front rake face 63 and the rear rake face 65 are also oriented in opposite directions. However, the feed hole 68 and the feed hole 69 are formed at positions that are offset from each other in the radial direction. Consequently, the feed holes 68 and 69, which have different orientations, can be formed in the shank 21 without obstruction between them.

[0095] As described above, the cutting part 61 of the tool 60 has the pair of machining edges 62 and 64. Therefore, adjusting the machining orientation during the chamfering step allows one of the edge sections 15b to be chamfered by machining edge 62 and the edge section 15c adjacent to edge section 15b in the circumferential direction to be chamfered by machining edge 64 during a rotation of the tool 60. In this case, compared to, for example, the first embodiment in which both of the adjacent edge sections 15b and 15c are chamfered by the same machining edge 24, the machining edges 62 and 64 can be formed into shapes suitable for the respective edge sections 15b and 15c, thus making it easy to adjust the size and angle of the chamfer to be provided to each of the edge sections 15b and 15c.

[0096] In particular, each of the machining edge 62 and the front rake face 63 is inclined further forward in the direction of rotation at a position closer to the rear end. The degree of inclination is set such that when the machining edge 62 is brought into contact with the edge section 15b, the area of ​​contact between them widens from the upper ridge face to the root face. Consequently, the entire edge section 15b can be chamfered by the machining edge 62 in a short time, and the upper ridge face and the root face of the edge section 15b are chamfered equally by the machining edge 62. Therefore, the size and angle of the chamfer to be provided to the edge section 15b can be set uniformly over the entire edge section 15b.

[0097] Similarly, each of the machining edge 64 and the rear rake face 65 is inclined further rearward in the direction of rotation at a position closer to the rear end. The degree of inclination is set such that when the machining edge 64 is brought into contact with the edge section 15c, the area of ​​contact between them widens from the upper ridge face to the root face. Consequently, the entire edge section 15c can be chamfered by the machining edge 64 in a short time, and the upper ridge face and the root face of the edge section 15c are chamfered equally by the machining edge 64. Therefore, the size and angle of the chamfer to be provided to the edge section 15c can be set uniformly over the entire edge section 15c.

[0098] Although the present invention has been described above based on the exemplary embodiments, it is not limited to these embodiments. It is readily apparent that various modifications can be made without departing from the core of the present invention.

[0099] The numerical values ​​used in the above embodiments are merely examples and can, of course, be replaced by other numerical values. For example, the number Zt of machining edges 24, 32, 36, 41, 51, 62, 64 (hereinafter referred to as "machining edge 24, etc.") provided to tools 20 to 60 can be one, two, or more. The surface roughness Rz of the rake face 25, 33, or 37, the flank face 26, 34, or 38, or the like, can be greater than 1.6.

[0100] Although a case in which the gear 10 is an external gear has been described in the above embodiments, the present invention is not limited thereto. The gear 10 can be an internal gear comprising: an annular component; and a plurality of teeth 12 projecting inwards in the radial direction from an inner circumferential surface of the annular component. Even without being limited to a case in which a flank line direction in which the teeth 12 extend is parallel to the axis of rotation C1, the flank line direction can be inclined from the axis of rotation C1.

[0101] Although a case in which the feed hole 22a, 68, 69 of the tool 20, 60 is spirally shaped has been described in the above embodiments, the present invention is not limited thereto. For example, the feed hole 22a, 68, 69 can be linear. The spiral or linear feed hole 22a, 68, 69 can also be provided on the tool 30, 40, 50.

[0102] Although a case in which the machining edge 24, 32, 36, 41, 51 is located on the imaginary plane Pr, which includes the tool axis C2, has been described in the above embodiments, it is permissible for the machining edge 24, 32, 36, 41, 51 not to be located on the imaginary plane Pr, similar to the machining edges 62 and 64. In this case, a plane is provided as a basis for determining the initial phase of the machining edge 24, etc., preferably on the outer circumferential surface of the shank 21 or the body 22. This basis plane is preferably parallel to the imaginary plane Pr to facilitate the identification of the phase of the machining edge 24, etc., that is to be rotated about the tool axis C2.

[0103] Although a case in which the edge section 15b and the edge section 15c are chamfered by the machining edge 24, 32, 36, 41, 51 of the same tool 20 to 50 in the chamfering step has been described in the above embodiments, the present invention is not limited thereto. It is permissible to change the machining orientation, the machining condition, the shape of the tool 20 to 50, or the like, as required, and to chamfer only the edge section 15b by the tool 20 to 50. In this case, it is permissible to chamfer only the edge section 15c by using a tool different from the tool 20 to 50 for chamfering the edge section 15b.

[0104] Although a case in which a tool 30 is provided with the machining edge 32 for chamfering the tooth root surfaces of the edge sections 15b to 15d and the machining edge 36 for chamfering the upper tooth web surfaces of the edge sections 15b to 15d was described in the second embodiment above, the present invention is not limited thereto. A tool for chamfering the tooth root surfaces of the edge sections 15b to 15d and a tool for chamfering the upper tooth web surfaces of the edge sections 15b to 15d can be manufactured separately. For example, it is permissible, after the edge sections 15b to 15d have been completely chamfered by the tool 20, to further chamfer only the upper tooth web surfaces of the edge sections 15b to 15d by another tool.

[0105] Although a case in which the direction of rotation Rw of the gear 10 and the direction of rotation Rt of the tool 20 to 60 are nearly identical near a section to be chamfered in the chamfering step has been described in the exemplary embodiments above, the present invention is not limited to this. It is permissible to set only the direction of rotation Rw to a direction opposite to the identical copying direction. In the case of the opposite direction, the machining edge 24, etc., rapidly chamfers the edge sections 15b to 15d of the gear 10 to form the chamfer sections 16b to 16d, thereby slightly reducing the angles of the chamfer sections 16b to 16d. In this case, if the outer diameter of the tool 20 to 60 is reduced, the angles of the chamfer sections 16b to 16d can be adjusted by increasing the angles.In other words, in the case of the opposite direction, the outer diameter of the tool is made slightly smaller by 20 to 60 than in the case of the copying direction.

[0106] Although examples of machining orientation in the chamfering step have been shown in the above embodiments, the machining orientation is not limited to the examples shown. The machining orientation only needs to be an orientation in which the axis of rotation C1 and the tool axis C2 are at least not parallel. For example, the machining orientation can correspond to a state in which: the tool axis C2 is inclined relative to the second imaginary plane P2 in the arrow-Y direction, as in the third embodiment; and the tool axis C2 is shifted parallel to a position on the first imaginary plane P1 in a direction perpendicular to it, as in the fourth embodiment.

[0107] Although a case in which the edge sections 15b to 15d of the gear 10 are chamfered by the tool 20 to 60 in the chamfering step has been described in the above embodiments, the present invention is not limited thereto. The machining orientation, the shape of the tool 20 to 60, or the like, can be modified such that the tool 20 to 60 chamfers the edge sections 15b and 15c of the gear 10 and does not chamfer the edge section 15d of the gear 10. Conversely, the machining orientation, the shape of the tool 20 to 60, or the like, can be modified such that the edge section 15d is chamfered and the edge sections 15b and 15c are not. The machining orientation, the shape of the tool 20 to 60 or the like can also be changed so that the tool 20 to 60 also chamfers the edge section 15a of the gear 10.

[0108] In the chamfering step where tool 20, 30, 40, or 60 is used, the machining orientation or the like can be changed so that only one of the edge sections 15b and 15c is chamfered and the other is not. In this case, as in the fourth embodiment above, it is permissible to partially change the machining orientation and then chamfer only the other of the edge sections 15b and 15c that was not chamfered before the change.

[0109] Although a case where the integer K is 1 in the chamfering step was presented as an example in the embodiments above, the integer K can be set to 2 or more. In a case where the integer K is 1, however, the majority of teeth 12 arranged in the circumferential direction can be chamfered by the machining edge 24, etc., without skipping any teeth in the chamfering step. Meanwhile, in a case where the integer K is 2 or more, the majority of teeth 12 arranged in the circumferential direction are chamfered by the machining edge 24, etc., skipping one or more of the teeth 12 in the chamfering step.

[0110] For example, in a case where the integer K is 2, the majority of teeth 12 are chamfered, skipping one of the teeth 12. In this case, if the number Zw of teeth 12 is odd, the tooth 12 that is skipped in the first rotation of the gear 10 is chamfered in the second rotation. That is, in the case where the integer K is 2 and the number Zw of teeth 12 is odd, the majority of teeth 12 can be chamfered equally without temporarily stopping the synchronous rotation of the gear 10 and the tool 20 to 60 in the same way as in the case where the integer K is 1. The same applies in a case where the integer K and the number Zw of teeth 12 are the same.

[0111] In a case where the integer K and the number Zw of teeth 12 are not equivalent, such as in a case where the integer K is 2 and the number Zw of teeth 12 is an even number, it is necessary, after temporarily stopping the synchronous rotation, to rotate only one of the gear 10 or the tool 20 to 60 and restart the synchronous rotation as in the chamfering step in the second embodiment above. In this case, the machining orientation or the like can be set so that it differs between before and after restarting the synchronous rotation. Consequently, the sizes and angles of the chamfers to be provided to the teeth 12 can be set so that they differ between before and after restarting the synchronous rotation. DESCRIPTION OF REFERENCE MARKS 10 gear 12 teeth 12b, 12c tooth flank 15b, 15c marginal section 16b, 16c Chamfer section 20, 30, 40, 50, 60 chamfering tool 24, 32, 36, 41, 51, 62, 64 processing edge 25, 33, 37 Chip surface 61 Cutting part 63 front chip surface 65 rear chip surface 66 Connecting surface C1 axis of rotation C2 tool axis P1 first imaginary plane P2 second imaginary level First imaginary plane (third imaginary plane, plane of rotation)

Claims

[1] A gear chamfering method comprising a chamfering step of chamfering, by means of a chamfering tool configured to be rotated about a tool axis, of a gear having a plurality of teeth formed about an axis of rotation, wherein Each of the multiple teeth exhibits the following: a tooth flank as a surface that is oriented in a circumferential direction of the gear, and a marginal section in an axial direction of the axis of rotation of the tooth flank, the chamfering tool has at least one machining edge which is formed around the tool axis into a shape that corresponds to a shape of the edge section, any integer is represented by K, the number of teeth is represented by Zw, and the number of machining edges is represented by Zt, and The chamfering step involves performing K·Zt / Zw rotations of the gear around the axis of rotation for each rotation of the chamfering tool around the tool axis in a machining orientation in which the tool axis is not set parallel to the axis of rotation, and sequentially bringing the machining edge into contact with a plurality of the edge sections in order to chamfer the edge sections. [2] The gear chamfering method according to claim 1, wherein the number Zt of machining edges is two or more, and The chamfering step involves bringing different machining edges into contact with the respective upper tooth ridge and tooth base surface of one of the edge sections in order to chamfer the upper tooth ridge and tooth base surface. [3] The gear chamfering method according to claim 1, wherein the machining orientation corresponds to a state in which the tool axis, which is located on a first imaginary plane which includes the axis of rotation, is displaced from the first imaginary plane in a direction perpendicular to the first imaginary plane parallel to the first imaginary plane. [4] The gear chamfering method according to claim 1, wherein the machining orientation corresponds to a state in which the tool axis is inclined from a second imaginary plane perpendicular to the axis of rotation. [5] The gear chamfering method according to claim 1, wherein the chamfering tool has a chip surface that extends from the machining edge to the tool axis side and is directed forward in a direction of rotation of the chamfering tool, the rake face and the machining edge are located on a third imaginary plane that includes the tool axis, and an initial phase of the machining edge at the beginning of the rotation of the machining edge around the tool axis in the chamfering step is determined on the basis of the rake face. [6] The chamfering tool to be used for the gear chamfering method according to claim 5, wherein the machining edge is a section with a radius that is smaller than a maximum radius of the chamfering tool, and is formed on a front end face in an axial direction of the chamfering tool, and the chip surface extends to one side opposite the front end beyond a position where the machining edge is formed. [7] The chamfering tool to be used for the gear chamfering process according to any one of claims 1 to 4, wherein the chamfering tool has a cutting part that is formed around the tool axis, the cutting part a front chip surface that faces forward in one direction of rotation of the chamfering tool, a rear chip surface that faces backwards in the direction of rotation of the chamfering tool, and a connecting surface that connects the radially outer boundaries of the front rake face and the rear rake face, and A cutting line between the joining surface and the front chip surface and a cutting line between the joining surface and the rear chip surface form a pair of machining edges that are configured to chamfer respective edge sections. [8] Chamfering tool manufacturing method for manufacturing the chamfering tool to be used for the gear chamfering method according to any one of claims 1 to 5, the chamfering tool has the processing edge and a chip surface extending from the machining edge to the tool axis side and facing forward in a direction of rotation of the chamfering tool, wherein the chamfering tool manufacturing process exhibits: a gear setting step of setting a shape of the gear including the number of teeth and a shape of a chamfer section to be formed by chamfering each of the edge sections; a rotation plane setting step of setting a shape of an imaginary plane of rotation to be rotated about the tool axis, wherein the imaginary plane of rotation is aligned in the direction of rotation of the chamfering tool; a condition setting step of setting an initial phase of the rotary plane, which is set in the rotary plane setting step, the machining orientation, the arbitrary integer K and the number Zt of machining edges; a capture step of capturing an intersection line between the plane of rotation and the chamfer section in each of the phases obtained when the K·Zt / Zw rotations of the gear about the axis of rotation during a rotation of the plane of rotation about the tool axis from the initial phase in the machining orientation based on the settings in the condition setting step and the gear setting step; and a training step of setting, as the machining edge, a line in contact with a plurality of the cutting lines that were captured in the sensing step, and of setting, as the rake surface, the plane of rotation closer to the tool axis than the machining edge, to form the chamfering tool.

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