JPH06277789A - Manufacture of gear having chamfer - Google Patents

Abstract

PURPOSE:To prevent lack of fill at the tip part of a chamfer by intensely pressing the axial end surface of a projecting tooth with a V-shaped wall surface of a chamfer forming die while facing the restricting wall surface of the chamfer forming to the tooth surface of the projecting tooth to execute a cold-forging for formation to the chamfer. CONSTITUTION:The V-shaped groove 40 in an upper punch 39 is formed with the V-shaped wall surface 41 having V-shaped bottom 41. While facing the restricting wall surface 44 of the punching die 39 to the tooth surface 10m in an inner tooth 10, the V-shaped wall surface 41 of the upper punching die 39 is intensely pressed to the axial end surface 10x at the upper side of the inner tooth 10, and by this method, the chamfer 17 having the inclining wall surface matching to the V-shaped wall surface 41 of the upper punching die 39 is formed. Therefore, by restraining the excess thickness on the tooth surface at the tooth surface 10m with the restricting wall surface 44, the surface pressure at the tip part 17e of the chamfer is risen and the formation of the sharp tip part can easily be obtd.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a gear having a chamfer which functions to guide a mating tooth to smooth the mesh. The method according to the invention can be applied, for example, to the manufacture of gears mounted on a manual transmission of a vehicle.

[0002]

2. Description of the Related Art Conventionally, mechanical devices equipped with gears have been provided. For example, a manual transmission of a vehicle is also equipped with gears having internal teeth. As a method of manufacturing this gear, the method disclosed in Japanese Patent Publication No. 56-33172 is known. That is, in this method, as shown in FIG. 14, a gear material 701 having a large number of inner teeth 700 formed along the circumferential direction is used, and V
Lower punch die 8 provided with a V-shaped wall surface 802 having a letter bottom 801
00 and an upper punch die 900 having a V-shaped wall surface 902 having a V-shaped bottom 901 are used.

The V-shaped wall surface 902 of the upper punch die 900 faces one shaft end surface 700a of the internal tooth 700 of the gear material 701. Further, the V-shaped wall surface 802 of the lower punch die 800 faces the other shaft end surface 700b of the internal tooth 700 of the gear material 701. When forming the chamfer, the lower punch die 8
With the gear material 701 set to 00, the upper punch die 900 is lowered, whereby the upper punch die 900 is brought closer to the lower punch die 800.

As a result, the shaft end surface 700a of the inner tooth 700 is strongly pressed by the V-shaped wall surface 902 of the upper punch die 900, and as a result, an inverted V-shape that substantially forms a mold object with the V-shaped wall surface 902 of the upper punch die 900. The first chamfer 705 is molded (see FIG. 16), and thereby the gear A is manufactured. In this method described above, the reverse taper surface 700c is formed on each of the pair of tooth surfaces 700m of the inner teeth 700 that face each other due to the padding during chamfer molding (FIG. 1).
6).

Similarly, the other shaft end surface 700 of the inner tooth 700 is formed.
Also in b, the reverse V-shaped second chamfer is molded and the reverse tapered surface is molded. When the gear A manufactured in this way meshes with the mating gear, as can be understood from FIG. 16, the external gear B, which is the mating gear rotated in synchronization with the gear A,
16 in the direction perpendicular to the paper surface of FIG.
The external teeth 951 of the external gear B are inserted between 0.
When inserted in this way, the first chamfer 705 having an inverted V shape serves to guide the external teeth 951 and makes the insertion of the external teeth 951 smooth.

[0006]

By the way, as can be understood from FIG. 16, the first chamfer 70 which performs the guiding function.
The tip 705a of No. 5 is sharp. Thus, it is not always easy to form the sharp tip 705a of the chamfer 705. In particular, in the above-described method, since the inverted taper surface 700c is formed on the tooth surface 700m due to the thickness increase on the tooth surface 700m of the internal tooth 700 as described above, the tip end 705a is apt to cause insufficient thickness and the sharp tip Since 705a cannot be obtained, a flat portion may remain. In this case, the smoothness of the shift change in the manual transmission is reduced.

The present invention has been made in view of the above situation, and an object thereof is to provide a method for manufacturing a gear having a chamfer, which is advantageous for obtaining a chamfer.

[0008]

According to the method of manufacturing a gear having a chamfer according to the present invention, any one of an inner peripheral portion and an outer peripheral portion of a projecting tooth having a pair of tooth surfaces that mesh with teeth of a mating gear and face each other. On one side, a large number of gear materials are formed along the circumferential direction, and a V-shaped wall surface provided with a V-shaped bottom that is provided so as to be relatively movable along the axial direction of the gear material and that faces the shaft end surface of the protruding teeth of the gear material. And a chamfer forming die that is provided continuously on the widening side of the V-shaped wall surface and that has a pair of constraining wall surfaces facing the tooth surfaces of the protruding teeth, and at least one of the protruding teeth of the gear material in the axial direction. On the side, the axial end surfaces of the projecting teeth are strongly pressed by the V-shaped wall surface of the chamfer forming die while facing the respective constraining wall surfaces of the chamfer forming die to the tooth surfaces of the projecting tooth, respectively, and the die surface and the V-shaped wall surface are substantially symmetrical to each other. Cold champagne It is characterized in that the step of forming and forming, and the step of forming an inverted taper surface that makes it difficult to remove the teeth of the mating gear, on at least a part of each tooth surface of the protruding tooth on which the chamfer is formed It is a thing.

[0009]

In the method of the present invention, when forming chamfers, the axial end surfaces of the projecting teeth are made to face each other while the constraining wall surfaces of the chamfer forming die face the respective tooth surfaces forming the projecting teeth of the gear material. Apply strong pressure on the V-shaped wall. Therefore, the constraining wall surface suppresses excessive padding on the tooth surface, so that the surface pressure of the chamfer tip portion increases, and the molding of the inferior tip becomes easy.

[0010]

EXAMPLE An example of the method of the present invention will be described with reference to FIGS. (Structure of Example) First, a ring-shaped forged product is used, and the ring-shaped forged product is cold-extruded to obtain a ring material 1 (material: SCR20) shown in FIGS. 1 and 2. On the inner peripheral portion of the ring material 1, except for the end portion 11, a plurality of inner teeth 10 as protruding teeth are continuously formed in the circumferential direction. 1 and 3, only a part of the internal teeth 10 is shown and the other internal teeth are omitted.

Next, the end portion 11 corresponding to the height H1 of the ring material 1 is cut and removed to obtain the gear material 2 having the height H3.
Next, the chamfer forming step is performed in the cold state. In this step, the device 3 shown in FIG. 5 is used. As shown in FIG. 5, the device 3 includes a holding plate 30 held on the lower bolster side.
A ring-shaped pressure plate 32 held by the holding plate 30, a knockout sleeve 33k inserted in the central hole 32i of the ring-shaped pressure plate 32, and a lower punch mold as a chamfer molding die fixed in the central hole 32i. 33, a ring-shaped outer mold 35 into which the ring-shaped inner mold 34 is press-fitted, an upper pressure-resistant board 37 held on the upper bolster side, a ring-shaped holding portion 38 held by the upper pressure-resistant board 37, and a ring-shaped holding The auxiliary portion 39k held by the portion 38 and the central hole 38 of the ring-shaped holding portion 38
Upper punch die 3 as a chamfer forming die held by i
9 and 9. In this device 3, when the mold is clamped,
The upper punch die 39 on the upper bolster side is lowered in the arrow Y1 direction by a drive mechanism (not shown). The cavity E is defined by the lowered upper punch die 39, lower punch die 33, and inner die 34.

Here, a large number of V-shaped grooves 40 are formed on the outer peripheral portion of the lower end portion of the upper punch die 39, that is, corresponding to the number of the inner teeth 10, and are formed in the same phase as the inner teeth 10 in the circumferential direction. . Further, the V-shaped groove 5 is also formed on the outer peripheral portion of the upper end of the lower punch die 33.
The number 0 corresponds to the number of the inner teeth 10, that is, the number of the inner teeth 10, and is formed in the same phase as the inner teeth 10 in the circumferential direction. Auxiliary part 39
The engaging portion 39e of k engages with the engaged portion 35n on the outer peripheral side of the ring-shaped outer die 35, and the lower punch die 33 in the circumferential direction.
The phase of the V-shaped groove 50 and the phase of the V-shaped groove 40 of the upper punch die 39 are matched.

As shown in FIG. 6A, the V-shaped groove 40 in the upper punch die 39 has a V-shaped wall surface 41 having a V-shaped bottom 41k.
Is formed by. Further, as shown in FIG. 7 (A), the V-shaped groove 50 in the lower punch die 33 has a V-shaped bottom 51k.
It is formed by a letter wall surface 51. The V-shaped wall surface 41 of the upper punch die 39 is the V-shaped wall surface 9 of the upper punch die 900 shown in FIG.
The chamfer is molded in the same manner as 02. Further, the V-shaped wall surface 51 of the lower punch die 33 forms a chamfer similarly to the V-shaped wall surface 802 of the lower punch die 800 shown in FIG. However, in the present embodiment, as shown in FIG. 6 (A), a pair of constraining wall surfaces 44 facing each other are continuously provided on the expansion side of the V-shaped wall surface 41 of the upper punch die 39. Further, as shown in FIG. 7 (A), the V-shaped wall surface 51 of the lower punch die 33.
A pair of constraining wall surfaces 54 facing each other is also provided continuously on the expansion side of the.

As shown in FIG. 6A, the constraining wall surface 44 of the upper punch die 39 faces the tooth surface 10m of the inner tooth 10 on the upper end side of the inner tooth 10 of the gear blank 2. is there. Further, as shown in FIG.
The constraining wall surface 54 of the inner tooth 10 is provided on the lower end side of the inner tooth 10.
10m of the tooth surface of each. And
As can be understood from FIGS. 8A and 8B, the lower punch die 33
With each inner tooth 10 of the gear blank 2 fitted and set in each V-shaped groove 50 of the above, the upper punch die 39 is lowered in the direction of the arrow Y1 to perform die clamping, and the upper punch die 39 approaches the lower punch die 33. Let

Then, as shown in FIG. 6 (A), the constraining wall surface 44 of the upper punch die 39 faces the tooth surface 10m of the inner tooth 10, and the upper punch die 39 of the upper punch die 39 faces the upper shaft end surface 10x of the inner tooth 10. The V-shaped wall surface 41 is strongly pressed, and as a result, the first chamfer 17, which is an inclined wall surface that substantially forms a mold object with the V-shaped wall surface 41 of the upper punch die 39, is formed as shown in FIG. 6B. Similarly, as shown in FIG. 7 (A), the constraining wall surfaces 54 of the lower punch die 33 face the tooth surfaces 10m of the inner teeth 10, respectively, while the lower punch die 33 is attached to the lower shaft end surface 10y of the inner tooth 10. The V-shaped wall surface 51 is strongly pressed, and as a result, a second chamfer 19 which is an inclined wall surface substantially forming a mold object with the V-shaped wall surface 51 of the lower punch die 33 is formed as shown in FIG.

9A and 9B, the inner teeth 10 are first
The state which formed the chamfer 17 and the 2nd chamfer 19 is shown. In FIGS. 9A and 9B, 10 r indicates the tooth crest surface which is the inner peripheral surface of the inner tooth 10, and 10 s indicates the tooth bottom surface of the inner tooth 10. After the chamfer forming step is performed as described above, the roll rolling step is then performed in a cold state. In this step, as shown in FIG. 11, a mandrel 51 having a large number of rolling grooves 50 on the outer peripheral portion and a rolling roll 53 having a flat roll outer peripheral surface 53c are used. Here, adjacent rolling grooves 5
The pitch of 0 in the circumferential direction corresponds to the pitch of the internal teeth 10 of the gear material 2 in the circumferential direction. As shown in FIG. 12, each rolling groove 50 of the mandrel 51 is
Is defined by a pair of tapered surfaces 53 that are inclined with respect to the axis K1 and that face each other, a continuous surface 54 that connects the pair of tapered surfaces 53, and an outer peripheral wall surface portion 55.

Then, as shown in FIG. 11, the mandrel 51 is inserted into the central hole 2h of the gear material 2 and the rolling roll 53 is arranged outside the gear material 2. In this state, the mandrel 51 is moved in the direction of the arrow X2. The mandrel 51 and the rolling roll 53 are rotated while pressing against the rolling roll 53 side. As a result, each inner tooth 10 of the gear material 2 is provided with each rolling groove 50.
Are intensified in order. As a result, as shown in FIG. 13, the taper surface 53 of the rolling groove 50 forms an inverse taper surface 73 in a region below the first chamfer 17. Specifically, the region of the mandrel 51 shown by hatching in FIG. 13 forms the region of the internal teeth 10 of the gear material 2 which is painted black. The reverse taper surface 73 is formed on each tooth surface 10m of the inner tooth 10.

Although not shown, another rolling groove is formed on the mandrel 51 below the rolling groove 50. Due to this other rolling groove, the reverse taper surface 75 is formed in the region above the second chamfer 19 on the tooth surface 10m of the inner tooth 10.
Are formed (see FIG. 10). Reverse taper surface 73, 75
16 has a function similar to that of the reverse taper surface 700c shown in FIG. 16, and enhances the engaging property with respect to the external teeth in a state where the external teeth of the external gear that is the mating gear and the internal teeth 10 of the gear mesh with each other. However, it is difficult to pull out external teeth.

A gear C having chamfers 17 and 19 and reverse taper surfaces 73 and 75 formed on each inner tooth 10 is obtained by the above-described steps. (Effects of Embodiment) As described above, in this embodiment, as shown in FIG.
While each constraining wall surface 44 of the upper punch die 39 facing each tooth surface 10m of the inner tooth 10 of the gear blank 2 shown in FIG. 1, one shaft end surface 10x of the inner tooth 10 is formed by the V-shaped wall surface 41 of the upper punch die 39. Press hard. Therefore, the constraining wall surface 44 causes the tooth surface 1
Excessive padding at 0 m is suppressed. Therefore, insufficient bulging at the tip 17e of the first chamfer 17 is suppressed, and the first chamfer 17 having the sharp tip 17e is obtained.

Similarly, according to this embodiment, the respective constraining wall surfaces 54 of the lower punch die 33 shown in FIG. 7 are made to face the tooth surfaces 10m of the internal teeth 10 of the gear material 2 while the other of the internal teeth 10 is made. The shaft end surface 10y is strongly pressed by the V-shaped wall surface 41 of the lower punch die 33. Therefore, the constraining wall surface 54 suppresses excessive padding on the tooth surface 10m. Therefore, the second chamfer 1
Insufficient padding at the tip of 9 is suppressed, and sharp tip 1
A second chamfer 19 with 9e is obtained.

(Other Examples) In the above-mentioned embodiment, the chamfer forming step is carried out on the internal teeth 10 formed by the extrusion molding of the gear material 2 as described above, but the invention is not limited to this, and it is formed by cutting. The inner teeth may be used and the chamfer forming step may be performed on the inner teeth. Further, in the above-described embodiment, as described above, the first chamfer 17 is formed on the upper ends of the inner teeth 10 and the second chamfer 19 is formed on the lower ends of the inner teeth 10, but the invention is not limited to this. Depending on the type, the chamfer may be formed only on one of the upper end and the lower end of the inner tooth 10.

Further, in the above-mentioned embodiment, it is applied to the internal teeth 10 of the internal gear as described above. However, the present invention is not limited to this, and may be applied to the case where the chamfer is formed on the external teeth of the external gear. good. Other than that, the method of the present invention is not limited to the embodiments described above and shown in the drawings, for example, can be applied to gears other than a manual transmission of a vehicle, and can be appropriately selected within a range not departing from the gist. Can be carried out.

[0023]

According to the method of the present invention, the axial end surfaces of the projecting teeth are strongly pressed by the V-shaped wall surface of the chamfer forming die, while the constraining wall surfaces of the chamfer forming die face the tooth surfaces of the projecting teeth of the gear material. Therefore, the constraining wall surface suppresses the wall thickness of the tooth surface. As a result, lack of padding at the tip of the chamfer is suppressed. Therefore, it is advantageous to make the tip of the chamfer sharp.

[Brief description of drawings]

FIG. 1 is a sectional view of a ring material.

FIG. 2 is a bottom view showing a ring material.

FIG. 3 is a cross-sectional view of a gear material.

FIG. 4 is a bottom view of the gear material.

FIG. 5 is a sectional view of a main part of a device for molding a chamfer.

FIG. 6A is a cross-sectional view schematically showing a state before forming the first chamfer on the inner teeth, and FIG. 6B is a cross-sectional view schematically showing a state after forming the first chamfer on the inner teeth. It is a figure.

FIG. 7A is a cross-sectional view schematically showing a state before forming the second chamfer on the inner teeth, and FIG. 7B is a cross-sectional view schematically showing a state after forming the second chamfer on the inner teeth. It is a figure.

8A is a cross-sectional view schematically showing a state in which a gear material is set in a lower punch die, and FIG. 8B is a schematic view in a state in which an upper punch die is clamped to a lower punch die in which a gear material is set. FIG.

9A is a front view of an internal tooth having a first chamfer and a second chamfer, and FIG. 9B is a first chamfer and a second chamfer.
It is a side view of the internal tooth provided with chamfer.

FIG. 10A is a front view of an internal tooth having a chamfer and an inverse tapered surface, and FIG. 10B is a side view of an internal tooth having a chamfer and an inverse tapered surface.

FIG. 11 is a perspective view of a state in which a roll rolling process is being performed.

FIG. 12 is a perspective view of a main portion before a reverse taper surface is formed on an inner tooth by a rolling groove.

FIG. 13 is a perspective view of a main part in a state after forming an inverse taper surface on an inner tooth by a rolling groove.

FIG. 14 is a cross-sectional view showing a state before the upper punch die is clamped to the lower punch die in which the gear material is set according to the conventional technique.

15A and 15B are cross-sectional views schematically showing a state in which a gear material is set in a lower punch die, and FIG. 15B is a lower punch die in which a gear material is set and an upper punch die is clamped according to the related art. It is sectional drawing which shows the state which carried out typically.

FIG. 16 is a diagram showing a state in which external teeth of a mating gear are inserted between internal teeth according to a conventional technique.

[Explanation of symbols]

In the figure, 2 is a gear material, 10 is an internal tooth (protruding tooth), 10 m is a tooth surface, 17 is a first chamfer, 19 is a second chamfer,
39 is an upper punch type (chamfer forming die), 33 is a lower punch type (chamfer forming die), 41 is a V-shaped wall surface, 41k is a V-shaped bottom, 44 is a constraining wall surface, 51 is a V-shaped wall surface, 51k is V
The letter bottom, 54 is a constraining wall surface, and 73 and 75 are reverse taper surfaces.

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[Procedure amendment]

[Submission date] October 21, 1993

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Correction target item name] Figure 8

[Correction method] Change

[Correction content]

[Figure 8]

[Procedure Amendment 2]

[Document name to be corrected] Drawing

[Name of item to be corrected] Fig. 10

[Correction method] Change

[Correction content]

[Figure 10]

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tatsuo Arima, 1041 Kano Co., Ltd., Higashi Osaka City, Osaka Prefecture, Yamanaka Gokin Co., Ltd.

Claims (1)

[Claims] 1. A gear material in which a large number of protruding teeth, which mesh with teeth of a mating gear and have a pair of tooth surfaces facing each other, are formed along the circumferential direction in either the inner peripheral portion or the outer peripheral portion, and the gear material. It is provided so that it can move relative to the axial direction of the material,
V having a V-shaped bottom facing the shaft end surface of the protruding teeth of the gear material
A chamfer forming die provided with a V-shaped wall surface, and a chamfer forming die continuously provided on the expansion side of the V-shaped wall surface and having a pair of constraining wall surfaces facing the respective tooth surfaces of the projection tooth. At least on one side in the axial direction of the chamfer forming die, while facing each constraining wall surface of the chamfer forming die to each tooth surface of the projecting tooth, the axial end surface of the projecting tooth is strongly pressed by the V-shaped wall surface of the chamfer forming die, Cold forging forming a chamfer that substantially forms a mold with the V-shaped wall surface, and making it difficult to extract the tooth of the mating gear on at least a part of each tooth surface of the protruding tooth on which the chamfer is formed. And a step of forming an inverted taper surface, which are performed in order, and a method for manufacturing a gear having a chamfer.