JPH0478362A - Cup gear and tooth form molding method thereof - Google Patents

Abstract

PURPOSE:To mold a tooth form higher than the height formed in the existing ironing molding through extremely easy manufacture without wasting material by heaping up a crest part corner part by material flow generated by the ironing of a root part during the ironing molding of an external tooth. CONSTITUTION:In a main punch 32, its tip part is formed thinner than its base part, and the punch tip part is provided with recessed parts 34, corresponding to the crest parts of th tooth form 22 of a die 20, formed at a constant pitch. That is, this recessed part 34 corresponds to the position f a lead-in part 23a formed at the upper end part of the crest part of the tooth form 22, and when the tip part of the punch 32 pushes a slug W in and is positioned at the lower end pat of the lead-in part 23a, the lead-in part 23a pushes a part of ironed raw material out into the recessed part 34. The tip of the punch 32 therefore enters into the tooth form 22 of the die 20, and the engagement is stopped at the lower end part of the lead-in part 23a, so that the tooth form 22 can be molded as far as the tip of a slug cylindrical part with no contact between the punch 32 and the lead-in part 23a of the tooth form 22.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a cup-shaped gear having external teeth and a method of forming the tooth profile.

[Prior Art and Problems to be Solved by the Invention] Conventionally, a cutting method has been used to manufacture a cup-shaped gear in which external teeth are formed on the outer surface of a cylindrical portion. However, cutting takes time, wastes material, and the height of the peaks (or valleys) that are the tooth profile features (
Increasing the depth requires a thicker material, which increases the amount of cutting and wastes material. Therefore, forming by ironing has been considered, but with conventional ironing, there is a limit to the height (depth) of the peaks (valleys) that can be formed based on the thickness of the material.

The present invention has been made in view of the problems of the prior art,
The purpose is to provide a method for forming cup-shaped gears and tooth shapes that can increase the height (depth) of peaks (valleys) for a given amount of material.

[Means to solve the problem]

In order to achieve the above object, in the cup-shaped gear according to the present invention, a die having a tooth profile for ironing formed on the inner circumferential surface and a punch facing the die are moved toward each other in the axial direction. , a cup-shaped gear in which an outer surface of a cylindrical portion of a cup-shaped slug is squeezed in the axial direction, and a tooth profile is formed on the outer surface of the cylindrical portion.

On the tip surface of each peak of the external tooth formed in the cylindrical part, there is a groove in the center of the tip surface of the peak to control the flow of material caused by ironing the valley during ironing of the external tooth. Accordingly, the corner portion of the top surface of the ridge portion is raised to the outside to form a raised portion here.

In addition, in the tooth profile forming method according to the present invention, a die having tooth profiles for ironing formed on the inner peripheral surface and a punch facing the die are moved toward each other in the axial direction to form a cup-shaped slag. A tooth forming method for a cup-shaped gear in which the outer surface of the cylindrical part is tightened in the axial direction to form a tooth profile on the outer surface of the cylindrical part. The section is raised in the height direction.

[Effect]

Since the tooth profile is formed by ironing simply by meshing the die and the punch, manufacturing is extremely easy and there is no waste of material compared to cutting. By guiding the material flow by trough ironing to the tip corner of the ridge, a raised part is formed at the tip corner of the crest, and the height (depth) of the crest (valley) is equal to the height of this raised part. growing.

〔Example〕

Next, embodiments of the present invention will be described based on the drawings.

Figures 1 (a), (b), and (c) are explanatory diagrams explaining how the tooth profile is formed on the outer surface of the cup-shaped slug, and Figure 1 (a) shows the state before the tooth profile is formed. A perspective view of a cup-shaped slug, FIG. 1(b) is a perspective view of the cup-shaped slug immediately after tooth formation, FIG. 1(c) is a perspective view of the cup-shaped gear as a product, and FIG. 2 is a cylinder of the cup-shaped gear. It is a horizontal cross-sectional view of a shaped part.

In these figures, reference numeral 1o in FIG. 1(c) indicates a cup-shaped gear, in which troughs 13 and peaks 14 are alternately and continuously formed on the outer surface of the cylindrical portion 11 by ironing. A tooth profile (external tooth) 12 is formed. Mountain part 1 of external tooth 12
4, the outside in the width direction (peak corner part) by ironing
A raised portion 16 is formed at the center, and a grooved portion 15 is formed at the center in the width direction. That is, as shown in FIG. 2, the valley portion 13 is squeezed, a part of the material in this area is pulled outward in the width direction of the peak, and the corner portion in the width direction is pushed upward (outward in the radial direction). It has a raised shape. The area sandwiched by the raised portions 16 and 16 serves as the grooved portion 15.

The cup-shaped slug before forming the external teeth 12 is shown by the symbol W in FIG. 1(a). As shown, a tooth profile 12 is formed on the outer surface of the cylindrical part, and as shown in FIG.
By cutting the open end side of the cylindrical portion at a position indicated by the symbol Ω, a cup-shaped gear 10 as shown in FIG. 1(c) is obtained.

3(a) and 3(b) are sectional views of the forming apparatus used in the method of the present invention, FIG. 3(a) is a sectional view of the forming apparatus before the punch is lowered, and FIG. b) is a sectional view of the forming device when the punch descends and forms the tooth profile, Fig. 4 is a perspective view of the main part of the main punch, and Fig. 5 shows how the slag is ironed and the tooth profile is formed. Explanatory drawings, FIGS. 6 and 7 are cross-sectional views along the lines vz-■ and g-■ shown in the fifth session, FIG. 8 is a longitudinal cross-sectional view of the introduction part of the tooth mold, and FIGS. 9 to 12.
The figure is an explanatory diagram illustrating how the cylindrical part is squeezed to form a tooth profile, and shows the lines IX-IX to gAX [
FIG.

In these figures, reference numeral 2o denotes a ring-shaped die, and on the inner periphery of the die 20 there are external teeth 12 on the outer surface of the cup-shaped slug W.
A tooth mold 22 for molding is formed. Tooth mold 22
As shown in FIG. 7, it consists of peaks 23 and valleys 24 formed at a constant pitch in the circumferential direction, and the bottom of the valleys 24 has a convexity extending in the axial direction (vertical direction in FIG. 5). Striped portion 24a
extends in the axial direction from the entrance side opening of the punch to the other end opening. The crest 23 extends in the axial direction from a position a predetermined depth away from the punch entrance side opening to the other end opening, and the upper end of the ridge 23 is tapered to allow the material to be introduced here. A portion 23a is formed. The lower end portion 23a1 of the material introducing portion 23a is a portion for squeezing the press-fitted material, and the tip surface of the peak portion 23 extends vertically from the squeezing portion 23a. Further, the protruding portion 24a is a portion that regulates the outer diameter of the central portion of the peak portion 14 of the external tooth 12.
It has the function of guiding a part of the material flow generated when the troughs are squeezed by the corners of the top end faces of the external teeth 12 only to the corners of the ridges. Note that the symbols 23b and 24b in FIG.
This is a recess formed on the surface of the tooth die 22, and is a gap for escape of the molding surface ironed by the tooth die 22. The die 2o is a die holder 26 (26a, 26b, 2
6c) from below, and the die 20
A slab presser 28 is arranged within the tooth pattern 22 forming portion to elastically support the bottom surface of the slug W and to knock out the slug W after the tooth formation shape. Above the die 20, there is a cylindrical sub-punch 30 that cooperates with the slag presser 28 to clamp the bottom surface of the slag W, and this sub-punch 30.
The main punch 3 is arranged on the outer periphery of the main punch 3 and is movable in the vertical direction.
2 are arranged.

The main punch 32 punches the open end of the cylindrical portion of the slag into the die 2.
The outer surface of the cylindrical part is pressed in the axial direction by pushing it into the tooth mold 22 of No. 0, and the external teeth 12 are formed here.

Note that the force for ironing is mainly applied by the main punch 32, but the sub-punch 30 that presses the bottom surface of the slag against the slag presser 28 also bears part of the downward pressing force for ironing. The tip of the main punch 32 is thinner than the base, and the tip of the punch has a constant recess 34 corresponding to the crest 23 of the tooth pattern 22 of the die 20, as shown in FIG. It is formed by pitch. That is, this recess 34 corresponds to the position of the introduction part 23a formed at the upper end of the peak 23 of the tooth mold 22,
The tip of the punch 32 pushes the slug W into the introduction section 23a.
When positioned at the lower end 23a, the introduction part 23a pushes out a part of the squeezed material (indicated by the symbol W in FIG. 1(b)) into the recess 34. For this reason, the tip of the punch 32 enters into the tooth pattern 22 of the die and the engagement stops at the lower end 23a1 of the introduction part, so that the punch 32 and the introduction part 23a of the tooth pattern 22 do not come into contact with each other and the slug cylindrical part A tooth profile can be formed all the way to the tip.

Next, the process of forming external teeth on the slug and the behavior of forming the tooth profile will be explained with reference to FIGS. 3(a) and 3(b) and FIGS. 5 to 12.

First, the slag presser 28 is raised to the vicinity of the open end of the die 2o, and the slug W is inserted into the lower end of the punch 30. Next, while holding the slag W with the slag presser 28, the punch 30 and main punch 32 are lowered together (
(See Section 3@(a)).

The slug W descends together with the punch along the convex strips 24a of the tooth mold 22, hits the introduction part 23a of the tooth mold 22, and thereafter the strong pressing force of the punch 32 acts on the opening end of the cylindrical part of the slug. As a result, the outer surface of the slag cylindrical portion is ironed by the teeth 22.

That is, the slug W slides along the tapered surface of the peak introduction part 23a, and reaches the final end of the introduction part 23a. Straining part 23a
, it is squeezed in the axial direction and undergoes plastic deformation. The strained material moves in the axial direction (see the arrow in Figure 8) and the circumferential direction (see the 10th arrow).
(see arrows in Figures to Figures 11) and undergoes plastic deformation.
As shown in the figure, the tooth profile 12 (peaks 14 and troughs 13) is formed to follow the tooth profile 22 (peaks 23 and troughs 24).

FIG. 8 is a longitudinal sectional view showing how the slag cylindrical part 11 is squeezed by the squeezing part 23a, and FIG.
- This is a cross-sectional view along ■.
It is about to come into contact with a and start deforming. FIG. 10 is a sectional view taken along the line XX shown in FIG. 8, and at this position a slight change has begun due to the introduction portion 23a. FIG. 11 is a cross-sectional view taken along the line XI-XI shown in FIG. FIG. 12 shows a state in which the space between the crests and troughs 24 of the tooth pattern 22 is filled with the strained material. After forming the tooth profile, the punches 30 and 32 are raised, and then the slag presser 28 is raised to knock out the slab. The removed slag is then subjected to the cutting process shown in FIG. 1(b) to produce the product shown in FIG. 1(c).

〔Effect of the invention〕

As is clear from the above description, according to the cup-shaped gear and tooth profile forming method according to the present invention, the tooth profile is formed by ironing by simply meshing a die and a punch, so manufacturing is extremely easy. At the same time, there is no waste of material compared to cutting processing.

In addition, due to the material flow caused by squeezing the tooth-shaped valley, the corner of the tip surface of the peak rises in the height direction, and the height (depth) of the peak (valley) increases by an amount equivalent to the height of this raised part.
Since this becomes larger, it is possible to form a tooth profile that is not only higher than the outer diameter of the slug, but also higher (deeper) than the height (depth) that can be formed by conventional ironing.

[Brief Description of the Drawings] Fig. 1(a) is a perspective view of a cup-shaped slug before a tooth profile is formed, Fig. 1(b) is a perspective view of a cup-shaped slag immediately after tooth formation, Fig. c) is a perspective view of the cup-shaped gear as a product, 2nd @ is a horizontal sectional view of the cylindrical part of the cup-shaped gear,
FIGS. 3(a) and 3(b) are cross-sectional views of a device for forming tooth profiles;
Figure 4 is a perspective view of the main punch, Figure 5 is a vertical cross-sectional view showing the state of the punch, slug, and die during ladder forming, and Figures 6 and 7 are lines VI-VI and line shown in Figure 5. Figure 8 is a horizontal cross-sectional view of the introductory part, and is an explanatory diagram explaining how the tooth profile is formed by squeezing. Figures 9 to 12 are respectively shown in Figure 8. It is a sectional view along @m-■~line store-store shown. DESCRIPTION OF SYMBOLS 10... Cup-shaped gear, 11... Cylindrical part, 12... Tooth profile (external tooth), 13... Valley part, 14... Peak part, 15... Center concave on the tip surface of peak part Line part, 16... bulge formed at the corner part of the top surface of the mountain part, W
...Cup-shaped slag, 20...Die, 22...Tooth mold for molding, 23a...Introduction part. 23a1...Stringing part, 32...Main punch. Figure 1 Patent applicant Yamakawa Kogyo Co., Ltd.
AIDA ENGINEERING CO., LTD. (0)

Claims (2)

[Claims] (1) The outer surface of the cylindrical portion of the cup-shaped slug is drawn in the axial direction by moving a die having teeth for ironing on its inner circumferential surface and a punch facing the die toward each other in the axial direction. It is a cup-shaped gear with a tooth profile formed on the outer surface of the cylindrical part, and the tip surface of each peak of the external teeth formed in the cylindrical part has a groove formed during ironing of the external tooth. A cup-shaped gear characterized in that the corner portion of the end surface of the ridge portion swells in the height direction due to the flow of material caused by the material flow, and the height of the ridge is increased for a given amount of material. (2) A die with teeth for ironing formed on the inner circumferential surface and a punch facing the die are moved toward each other in the axial direction, so that the outer surface of the cylindrical portion of the cup-shaped slug is axially pressed. This is a tooth forming method for a cup-shaped gear in which a tooth profile is formed on the outer surface of a cylindrical part by ironing, and the material flow caused by the troughs being squeezed during ironing of the external teeth causes the corner part of the tip surface of the crest to become high. A tooth forming method for a cup-shaped gear, which is characterized in that it bulges in the horizontal direction and the height of the crest is increased for a certain amount of material.