Gear manufacturing method

Abstract

To provide a gear production method capable of achieving desired tooth form accuracy when changing the tooth form in a tooth muscle direction of a workpiece in skiving processing.SOLUTION: There is provided a gear production method configured to produce a gear by cutting processing to a workpiece 300 by using a skiving cutter 200, the method is configured so that: a denture mold 300a of a base is cut with respect to the workpiece 300, a distance D between axes between the workpiece 300 and the skiving cutter 200 is adjusted, and at least one of tooth tips 304a, 304b of tooth surfaces 302a, 302b of the denture mold 300a of the base and roots 306a, 306b (cutting each side of the tooth tips and each side of the roots), at the time, during cutting of the tooth surfaces, the distance between axes is further adjusted for forming any shape out of crowing, relieving, taper shapes or forming a combined shape of combining these shapes.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a gear manufacturing method for manufacturing a gear by cutting a workpiece using a skiving cutter. [Background technology]

[0002] Skiving using a skiving cutter is a well-known method for manufacturing gears. Patent Document 1 discloses a processing support device that supports the processing of a workpiece during skiving. The processing support device in Patent Document 1 includes a "target modification amount memory unit that stores target modification amounts for at least two of the modification elements of the tooth flank shape of a gear tooth, namely crowning, bias, helix angle, pressure angle, and tooth profile roundness," and a "correction amount determination unit that determines correction amounts for processing control elements during processing operations so that at least two of the modification elements approximate the target modification amounts stored in the target modification amount memory unit." [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-11011 Summary of the Invention [Problem to be solved by the invention]

[0004] When changing the tooth profile in the tooth trace direction of the workpiece during skiving, it is necessary to change the helix angle and offset angle while performing the skiving cutting feed (processing operation), i.e., to change the processing operation, as in Patent Document 1. However, changes in the intersection angle and offset angle cause changes in the processing point and cutting resistance, making it difficult to obtain the desired tooth profile accuracy.

[0005] In view of the above problems, the present invention aims to provide a gear manufacturing method that can obtain the desired tooth profile accuracy when changing the tooth profile in the tooth trace direction of the workpiece during skiving. [Means for solving the problem]

[0006] In order to solve the above problems, a typical configuration of the gear manufacturing method according to the present invention is a gear manufacturing method in which a workpiece is cut using a skiving cutter to manufacture a gear, characterized in that a base tooth form is cut into the workpiece, and the axial distance between the workpiece and the skiving cutter is adjusted to cut at least one of the tip and root of the tooth flank of the base tooth form, one side at a time, and the axial distance is further adjusted during cutting of the tooth flank to form any one of a crowning, relieving or tapered shape, or a combination thereof.

[0007] It is advisable to perform helical complementation during cutting of the tooth tip or root of the tooth flank.

[0008] At least two types of skiving cutters, a first skiving cutter and a second skiving cutter, are used, and the base tooth form is cut with the first skiving cutter, and when cutting the tooth tip or tooth base of the tooth flank, the second skiving cutter, which has a thinner tooth thickness than the first skiving cutter, is used. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a gear manufacturing method that can obtain the desired tooth profile accuracy when changing the tooth profile in the tooth trace direction of the workpiece during skiving. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram illustrating a gear manufacturing apparatus used in a gear manufacturing method according to an embodiment of the present invention. [Figure 2] FIG. 2 is a diagram illustrating the skiving cutter of FIG. 1. [Figure 3] 2(b) is a diagram illustrating a method for correcting the cutting depth when cutting using the second cutter of FIG. [Figure 4]3 is a diagram illustrating details of cutting work when forming a crowning shape or a tapered shape on the tooth surface of the workpiece in FIG. 2. FIG. [Figure 5] 3A and 3B are diagrams illustrating details of cutting work when forming a relieving shape or a combined shape of a relieving shape and a crowning shape on the tooth surface of the workpiece in FIG. 2. [Figure 6] FIG. 3 is a diagram illustrating details of cutting when forming a combined shape of a relieving shape, a crowning shape, and a tapered shape on the tooth surface of the workpiece in FIG. 2, or when forming a crowning shape on the tooth tip and a relieving shape on the tooth base. DETAILED DESCRIPTION OF THE INVENTION

[0011] Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Dimensions, materials, and other specific values ​​shown in the embodiments are merely examples for facilitating understanding of the invention and, unless otherwise specified, do not limit the present invention. In this specification and drawings, elements having substantially the same functions and configurations are designated by the same reference numerals to avoid redundant explanation, and elements not directly related to the present invention are not shown or described.

[0012] Fig. 1 is a diagram illustrating a gear manufacturing apparatus 100 used in a gear manufacturing method according to this embodiment. Fig. 1(a) is a view from the direction in which a cutter 200 and a workpiece 300 overlap, and Fig. 1(b) is a view from the direction in which the cutter 200 and the workpiece 300 are arranged side by side. In the gear manufacturing method of this embodiment, a bias-in gear (a gear whose pressure angle changes in the face width direction) is manufactured by cutting the workpiece 300 using a skiving cutter (hereinafter referred to as the cutter 200) of the gear manufacturing apparatus 100 shown in Fig. 1.

[0013] As shown in Figure 1, in a gear manufacturing apparatus 100, a cutter 200 is attached to a tool spindle (not shown) via a holder 102. A workpiece 300 is held in a chuck 104 and is cut while rotating in synchronization with the cutter 200. In the gear manufacturing apparatus 100 shown in Figure 1, the operations of the cutter 200 and chuck 104 are controlled by a control unit 110. In reality, as will be described later, multiple skiving cutters are denoted by the reference numerals 210 and 220, but in Figure 1 they are shown as cutter 200 for ease of explanation.

[0014] 1 in particular illustrates an example of the posture of the gear manufacturing apparatus 100 during operation. When performing cutting, the control unit 110 controls the cutter 200 and the chuck 104, so that the workpiece 300 rotates at a predetermined rotation speed around a rotation axis A1 (rotation axis A1 is also referred to as the workpiece axis), and the cutter 200 also rotates at a predetermined rotation speed around a rotation axis A2 (rotation axis A2 is also referred to as the tool axis). As shown in FIG. 1(a), the cutter 200 moves from the upward direction to the downward direction in FIG. 1 while maintaining the crossing angle γ (in the case of a first machining step, which will be described later) formed by the two rotation axes A1 and A2, thereby cutting the workpiece 300 and manufacturing a gear.

[0015] Fig. 2 is a diagram illustrating the skiving cutter of Fig. 1. When manufacturing a gear, first, as shown in Fig. 2(a), a first skiving cutter (first cutter 210) is used to cut a base tooth form 300a into a workpiece 300 (normal gear cutting process). More specifically, the tooth thickness of the first cutter 210 is set to a reference tooth thickness t1. Then, the first cutter 210 is used to simultaneously cut the tooth form 300a consisting of a tooth root 312 and adjacent tooth flanks 302a and 302b on the workpiece 300.

[0016] In this embodiment, the tooth flanks 302a and 302b are simultaneously cut to form the tooth mold 300a, but the present invention is not limited to this. For example, the tooth flanks 302a and 302b may be cut one by one to form the tooth mold 300a.

[0017] Next, as shown in Figure 2(b), a second skiving cutter (second cutter 220) having a tooth thickness t2 thinner than that of the first cutter 210 is used to cut the tips 304a and 304b or the roots 306a and 306b (particularly the roots 306a and 306b) of the tooth flanks 302a and 302b of the tooth mold 300a (tooth tip and root cutting process).

[0018] In particular, in the gear manufacturing method of this embodiment, when cutting the tooth tips 304a and 304b or the tooth roots 306a and 306b of the tooth flanks, the tooth tips 304a and 304b or the tooth roots 306a and 306b of the tooth flanks 302a and 302b of the base tooth form 300a are cut on one side at a time.

[0019] FIG. 3 is a diagram illustrating a method for correcting the cutting depth during cutting using the second cutter shown in FIG. 2(b). One method for correcting the cutting depth is to adjust the center distance D between the workpiece 300 and the second cutter 220 (see FIG. 1(b)). Another method is to correct the cutting depth in the rotational direction. In skiving, the cutting depth in the rotational direction can be corrected by adjusting the phase (machining allowance) when the cutter 200 and the workpiece 300 are rotated synchronously. Helical interpolation can be performed by correcting the cutting depth according to the feed of the cutter 200 (the cutter 200 is fed from top to bottom in FIG. 1). Crowning, relieving, or tapered shapes, or a combination of these shapes, can be formed by appropriately combining the adjustment of the center distance D and the phase with helical interpolation during cutting of the tooth tips 304a and 304b or the tooth roots 306a and 306b of the tooth flanks 302a and 302b.

[0020] FIG. 4 is a diagram illustrating details of cutting when forming a crowning shape or a tapered shape on the tooth flank of the workpiece shown in FIG. 2. FIG. 5 is a diagram illustrating details of cutting when forming a relieving shape or a combined shape of a relieving shape and a crowning shape on the tooth flank of the workpiece shown in FIG. 2. FIG. 6 is a diagram illustrating details of cutting when forming a combined shape of a relieving shape, a crowning shape, and a tapered shape on the tooth flank of the workpiece shown in FIG. 2, or when forming a crowning shape on the tooth tip and a relieving shape on the tooth base. FIGS. 4 to 6 illustrate an example in which tooth flank 302a of tooth flanks 302a and 302b is cut. Note that cutting is performed from top to bottom on the tooth tip 304a, and cutting is performed from bottom to top on the tooth base 306a.

[0021] 4(a) is a diagram illustrating a workpiece 300 having a crowning shape formed on the tooth surface 302a. When grinding the tooth tip 304a, the center distance D is adjusted so that the tooth 222 of the second cutter 220 moves away from the workpiece 300 from P11 to P12, and the tooth 222 is ground in an arc shape, and the center distance D is adjusted so that the tooth 222 moves closer to the workpiece 300 from P12 to P13, and the tooth 222 is ground in an arc shape.

[0022] When grinding the root 306a, the synchronous phase is adjusted to correct the cutting depth in the rotational direction. The phase is adjusted so that the machining allowance decreases in an arc shape from P11 to P12, and so that the machining allowance increases in an arc shape from P12 to P13. This forms a crowning shape with the center of the tooth width bulging out from the tooth surface of the workpiece 300.

[0023] 4(b) is a diagram illustrating a workpiece 300 having a tapered shape (bias-in tooth profile) formed on the tooth surface 302a. When grinding the tooth tip 304a, the center distance D is adjusted so that the tooth of the second cutter 220 approaches the workpiece 300 from P21 to P22 and P23.

[0024] When grinding the root 306a, the synchronization phase is adjusted so that the machining allowance decreases from P21 to P22 and P23 (helical interpolation), thereby forming a tapered shape (bias-in tooth profile) on the tooth surface of the workpiece 300.

[0025] 5(a) is a diagram illustrating a workpiece 300 having a relieving shape formed on the tooth surface 302a. When grinding the tooth tip 304a, the center distance D is adjusted so that the tooth 222 of the second cutter 220 moves away from the workpiece 300 from P31 to P32, and the tooth tip 304a is ground. When the tooth 222 of the second cutter 220 reaches P32, the center distance D is maintained while grinding the tooth tip 304a from P32 to P33. When the tooth of the second cutter 220 reaches P33, the center distance D is adjusted so that the tooth moves closer to the workpiece 300, and the tooth tip 304a is ground from P33 to P34.

[0026] When grinding the tooth base 306a, the synchronization phase is adjusted so that the machining allowance decreases from P31 to P32, then uniform grinding is performed from P32 to P33, and grinding increases from P33 to P34. As a result, both ends in the tooth width direction of the tooth tip 304a and tooth base 306a of the workpiece 300 are cut deeply, and a relieving shape is formed in which the areas other than both ends are cut parallel to the tooth trace.

[0027] 5(b) is a diagram illustrating a workpiece 300 on which a combined shape of relieving and crowning has been formed on the tooth flank 302a. When grinding the tooth tip 304a, the center distance D is adjusted so that the tooth 222 of the second cutter 220 moves away from the workpiece 300 in an arc from P41 to P42, and the tooth tip 304a is ground. When the tooth 222 of the second cutter 220 reaches P42, the curvature of the arc is made smaller (gentler), and the center distance D is adjusted in an arc shape so that P43 in the center becomes the apex, i.e., the center distance D at P43 is the furthest from the workpiece 300, and the tooth tip 304a is ground from P42 to P44. When the tooth 222 of the second cutter 220 reaches P44, the curvature of the arc is increased (returned) and the center distance D is adjusted so that the tooth approaches the workpiece 300 in an arc shape, and the tooth tip 304a is ground from P44 to P45.

[0028] When grinding the tooth base 306a, the synchronization phase is adjusted so that the machining allowance is reduced in an arc shape from P41 to P42, the phase is adjusted so that the curvature is reduced to form an arc shape from P42 to P44, and the phase is adjusted so that the curvature is increased (returned) to form an arc shape from P44 to P45. As a result, the tooth tip 304a and tooth base 306a of the workpiece 300 are cut deeply at both ends in the face width direction, and a combined shape of relieving and crowning is formed in which the center of the face width is cut to bulge out except for the both end portions.

[0029] Fig. 6(a) is a diagram illustrating a workpiece 300 in which a combined shape of relieving, crowning, and taper is formed on a tooth surface 302a. The combined shape can be formed by adding the correction amount of taper explained using Fig. 4(b) and the correction amounts of relieving and crowning explained using Fig. 5(b).

[0030] 6(b) is a diagram illustrating a workpiece 300 in which a crowning shape is formed on the tooth tip 304a and a relieving shape is formed on the tooth root 306a. The crowning shape is formed on the tooth tip 304a as described using FIG. 4(a). The relieving shape is formed on the tooth root 306a as described using FIG. 5(a). In this way, the tooth tip 304a and the tooth root 306a of the workpiece 300 may have different machined shapes.

[0031] As described above, according to the gear manufacturing method of this embodiment, by adjusting the axial distance D between the workpiece 300 and the cutter 200 (strictly speaking, the second cutter 220) when cutting in the tooth trace direction, it is possible to form a wide variety of shapes on the tooth flanks in the tooth trace direction. This makes it possible to machine more complex shapes on the tooth flanks 302a and 302b, thereby meeting a wide range of needs.

[0032] In the gear manufacturing method of this embodiment, the first cutter 210 and the second cutter 220 are used to cut the workpiece 300, but the present invention is not limited to this, and a gear may be manufactured using only the first cutter 210. In this case, however, the width of the tooth bottom of the workpiece 300 and the width of the cutting edge of the first cutter 210 are the same. In order to cut the tooth flanks one side at a time despite this, the crossing angle γ can be increased so that the tooth tip of the first cutter 210 does not come into contact with the tooth flank on the side not being cut.

[0033] While the preferred embodiments of the present invention have been described above with reference to the accompanying drawings, it goes without saying that the present invention is not limited to these examples. It is clear that those skilled in the art can conceive of various modifications and alterations within the scope of the claims, and it is understood that these modifications and alterations also fall within the technical scope of the present invention. [Explanation of symbols]

[0034] 100... gear manufacturing device, 102... holder, 104... chuck, 110... control unit, 200... skiving cutter, 210... first cutter, 220... second cutter, 222... tooth, 300... workpiece, 300a... tooth profile, 302a... tooth surface, 302b... tooth surface, 304a... tooth tip, 304b... tooth tip, 306a... tooth base, 306b... tooth base, 312... tooth root

Claims

[Claim 1] A gear manufacturing method for manufacturing a gear by cutting a workpiece using a skiving cutter, comprising: As the skiving cutter, at least two types of skiving cutters are used: a first skiving cutter and a second skiving cutter having a tooth thickness thinner than that of the first skiving cutter; Cutting a base tooth form into the workpiece with the first skiving cutter; When adjusting the axial distance between the workpiece and the second skiving cutter and cutting at least one of the tip and the root of the tooth flank of the tooth form of the base by the second skiving cutter, a gear manufacturing method comprising: performing helical interpolation during cutting of the tooth flanks; and further adjusting the center distance to form a crowning, relieving, or tapered shape, or a combination thereof.

Images