JP2717391B2 - Crest forming method for sheet metal internal gear - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for forming a ridge of a sheet metal internal gear.

[0002]

2. Description of the Related Art Conventionally, cup-shaped parts having internal gears, such as viscous coupling covers and transmission parts, which are used in differentials of automobiles, are generally formed by subjecting steel to hot forging or warm forging. It is formed into the shape of an internal gear, and then the material is cut by machining to form a finished product.

[0003]

However, in the conventional working method, it is necessary not only to heat the steel material to a temperature required for hot forging or warm forging, but also to include a forging step and a machining step in the working step. And production efficiency is poor,
In addition, there are various problems that skill is required to obtain the accuracy required for the internal gear.

Accordingly, the inventor of the present application attached a sheet metal cup-shaped material W having a cylindrical peripheral wall 102 continuously connected to the outer periphery of a substrate portion 101 as shown in FIG. The forming roller 3 is approached to the peripheral wall 102 of the cup-shaped material W rotating together with the mold 1 as indicated by an arrow z, and when the forming roller 3 comes into contact with the cup-shaped material W, the forming roller 3 is moved to the cup-shaped material W. While rotating, the cup-shaped material W is pressed against the rotating inner mold 1 by the forming roller 3, whereby the peripheral wall 102 is inserted into the recess-formed space 11 for forming a mountain portion provided on the outer peripheral surface of the rotating inner mold 1. An attempt was made to increase the thickness of a portion of the peripheral wall 102 corresponding to the recessed space 11 by flowing the meat to form a mountain portion of the internal gear. In FIG. 14, reference numeral 2 denotes a holding type.

However, as shown in FIG. 15, the internal gear 200 formed by this method may have a notched portion 202a at the end including the axially open end surface of the ridge 202. In this case, the ridge 202 is formed. Figured out that it was incomplete. In addition, there may be a case where a notched portion 204a is formed at the base of the crest 202 of the internal gear 200, and the crest 202 is finished in an incomplete shape.

SUMMARY OF THE INVENTION The present invention has been made under the above-mentioned circumstances. In the case where the peripheral wall of a cup-shaped material is thickened at a position corresponding to a concavely formed space of a rotating inner die to form a mountain portion of an internal gear. In addition, by taking measures to prevent the underfill portion from forming at the end portion including the axially open end surface of the ridge portion, the end portion including the axially open end surface of the ridge portion of the formed internal gear has no undercut portion. It is an object of the present invention to provide a method for forming a ridge portion of a sheet metal internal gear that can be accurately finished in a shape. Further, in the above case, not only the end portion including the axially open end surface of the peak portion,
By taking measures to prevent the underfill from forming at the root of the ridge, a sheet metal that can accurately finish the axially open end of the ridge of the formed internal gear into a shape without the underfill. An object of the present invention is to provide a method for forming a ridge of an internal gear.

[0007]

According to a first aspect of the present invention, there is provided a method for forming a ridge of an internal gear made of sheet metal, comprising a ridge open end forming surface for forming an axial open end surface of the ridge at an end. A gear forming surface in which a concave forming space for forming a ridge and a convex portion for forming a valley are arranged in the circumferential direction, and the gear forming surface is axially adjacent to the gear forming surface with the ridge open end forming surface as a boundary. After attaching a cup-shaped material in which a cylindrical peripheral wall is continuously provided on the outer periphery of the substrate portion to a rotating inner mold having a cylindrical surface, and in a state where the tip of the peripheral wall faces the cylindrical surface, the rotating inner mold is formed. While rotating the cup-shaped material together, the peripheral wall of the cup-shaped material is pressed at a fixed position on the rotating inner mold side at a position near the ridge open end forming surface to flow the meat of the peripheral wall into the concave molding space. By doing so, the peripheral wall is increased in thickness at the location corresponding to the concave molding space, and the axially open end face of the peak is Then, the peripheral wall of the cup-shaped material is pressed against the rotating inner mold side, and the wall of the peripheral wall is caused to flow into the concave molding space so that the peripheral wall corresponds to the concave molding space. In other words, the remaining portion of the mountain is formed by increasing the thickness at the location.

According to this method, before the entire ridge portion of the internal gear is formed, the end portion including the axially open end surface of the ridge portion is formed, so that the remaining portion of the ridge portion is formed thereafter. As a result, the ridge is accurately finished in a shape having no underfill at the end including the axially open end surface. This effect is achieved by the step of forming only the end including the axially open end face of the ridge, as in the invention according to claim 3, by contacting the peripheral wall of the cup-shaped material at a location close to the ridge open end forming surface. It is also exerted by moving the forming roller rotating with the cup-shaped material in the direction approaching the rotating inner mold.

In the above method, when only the end portion including the axially open end surface of the mountain portion is formed, the cylindrical surface of the rotary inner mold and the cup-shaped material are brought into contact with each other. The peripheral wall of the cup-shaped material is sandwiched between the annular member and the encircling member, and the annular member is cut into the peripheral wall so that the meat of the peripheral wall flows outward through the gap between the annular member and the cylindrical surface. It is desirable to limit

According to this method, the phenomenon in which the wall of the peripheral wall of the cup-shaped material pressed at a fixed position toward the rotary inner mold flows outward from the gap between the annular member and the cylindrical surface and escapes is suppressed. Accordingly, the tendency of the flesh of the peripheral wall of the cup-shaped material to flow into the concave molding space of the rotary inner mold is increased, and the end portion including the axially open end surface of the peak portion is reliably formed. This effect is also exerted by using a forming roller integrally provided with the annular member as in the invention according to claim 4.

According to a fifth aspect of the present invention, there is provided a method for forming a ridge of a sheet metal internal gear, comprising a ridge forming end concave surface for forming an axially open end surface of the ridge at an end thereof. A gear forming surface in which a forming space and a convex portion for forming a valley portion are arranged in a circumferential direction, and a cylindrical surface axially adjacent to the gear forming surface with the ridge open end forming surface as a boundary. A cup-shaped material in which a cylindrical peripheral wall is continuously provided on the outer periphery of the substrate part,
After the tip of the peripheral wall is attached in a state facing the cylindrical surface, while rotating the cup-shaped material together with the rotating inner die, the connecting portion between the substrate portion of the cup-shaped material and the peripheral wall is moved to the rotating inner die side. Pressing at a fixed position causes the flesh of the continuous portion to flow into the concave molding space, and thereby increases the continuous portion at a position corresponding to the concave molding space, thereby increasing the thickness of the internal gear at the peak portion. Molding only the base part on the side of the continuous part, and rotating the cup-shaped material together with the rotating inner mold, the peripheral wall of the cup-shaped material is fixed on the rotating inner mold side at a point near the above-mentioned open end molding surface By pressing the peripheral wall to flow into the concave molding space, the peripheral wall is thickened at a position corresponding to the concave molding space, and only the end including the axially open end surface of the peak is formed. And rotating the peripheral wall of the cup-shaped material Side to press the peripheral wall to flow into the concave molding space, thereby increasing the thickness of the peripheral wall at a location corresponding to the concave molding space to form an intermediate portion of the peak portion, It is done in order.

According to this method, a ridge having no underfill at any of the root portion and the end portion including the axially open end surface is formed with high precision.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIGS. 1 to 8 show the entire process of manufacturing a sheet metal internal gear. FIG. 5 to FIG.
FIGS. 4 to 8 are explanatory diagrams showing an embodiment of the invention according to claim 4, and FIGS. 4 to 8 are explanatory diagrams showing an embodiment of the invention according to claim 5.

FIG. 1 shows a material A obtained by forming a bulge 100 at the center of a circular flat sheet metal material.
Is shown in a partial end view. In the material A, a known method such as a press can be adopted as a method of forming the bulging portion 100.

A peripheral wall is formed on the material A of FIG. 1 by a known method such as pressing or rolling. The cup-shaped material (hereinafter, referred to as “work”) W formed in this manner is shown in FIG. This work W has a cylindrical peripheral wall 102 provided continuously on the outer periphery of a substrate portion 101.
Is slightly thicker than the original material A. Note that FIG.
Although the peripheral wall 102 of the workpiece W is slightly curved, the peripheral wall 102 may be a cylindrical wall protruding in a direction orthogonal to the substrate 101 or the substrate 101
It may be a conical wall that protrudes in a divergent shape.

The peripheral wall 102 of the work W is formed through the intermediate step shown in FIG. 2 and finally through the step shown in FIG. That is, in the intermediate step of FIG. 2, while the forming roller 9 is brought into contact with the material A of FIG. The outer peripheral portion of the material A is pressed by the arcuate forming surface 91 as indicated by an arrow y.
Through this intermediate step, the outer peripheral portion 102a of the material A
Is formed into a short arcuate shape along the forming surface 91. Next, instead of the forming roller 9 of FIG. 2, a forming roller 9A shown in FIG. 3 is combined. Then, the forming roller 9A is brought into contact with the short arc-shaped outer peripheral portion 102a to rotate the forming roller 9A, and the forming surface 9 of the forming roller 9A having a long arc shape is provided.
The short arc-shaped outer peripheral portion 102a of the material A is marked with an arrow y '
The peripheral wall 102 curved in a long circular arc shape is formed as shown in FIG. The forming roller 9 used in the process of FIG. 2 has a receiving surface 92 for the outer peripheral end surface of the material A.
Of the material A
The thickness of the outer peripheral portion 102a and the peripheral wall 102 formed in the step of FIG.

When the step of forming the peripheral wall 102 is performed in two steps described with reference to FIGS.
This is preferable because the meat does not overlap with the meat at the end portion.

An inner gear forming step is performed on the peripheral wall 102 of the work W formed through the steps shown in FIGS.

In this embodiment, the rotary inner die 1 and the presser die 2 are commonly used in all the steps of manufacturing a sheet metal internal gear. The rotary inner die 1 has a gear forming surface P1 and a cylindrical surface P having a concave forming space 11 for forming a mountain portion and a convex portion 12 for forming a valley portion, which are alternately arranged at equal intervals in the circumferential direction on the outer peripheral surface thereof.
2 is provided. One end side in the axial direction of the recess-formed space 2 is open, and the other end side has an axially open end surface of a mountain portion (described later).
Is formed, and the gear forming surface P1 and the cylindrical surface P2 are axially adjacent to each other with the peak open end forming surface 13 as a boundary. The axial length (axial length) of the recessed space 11 and the convex portion 12 is adjusted to the axial length of the ridges and valleys (described later) of the internal gear formed by forming the peripheral wall 102. Properly defined.

The rotational force of a drive source (not shown) is transmitted to the rotary inner mold 1. In the first step of forming, the forming roller 3 is combined with the rotating inner mold 1. The presser die 2 is necessary to hold the work W between the rotary inner die 1 and the work W. The presser die 2 rotates around the rotary inner die 1 while holding the work W.

The forming roller 3 can be moved toward and away from the rotating inner mold 1 in a direction orthogonal to the axis thereof, and is moved from a position away from the rotating inner mold 1 to a direction gradually approaching during molding. As illustrated in FIG. 4, the forming roller 3 includes a tapered inclined forming surface 31 that contacts a continuous portion 103 between the substrate portion 101 and the peripheral wall 102 of the work W, and an inclined pressing surface 32. The inclined pressing surface 32 is provided continuously with the smallest diameter portion of the inclined forming surface 31, has the same inclination direction as the inclined forming surface 31, and has a tapered shape that is gentler to the axis than the inclined forming surface 31. It has become. The inclination angle of the inclined molding surface 31 with respect to the axis is 45 °, and the inclination angle of the inclined pressing surface 32 with respect to the axis is 3 °. The molding roller 3 rotates together with the workpiece W when the inclined pressing surface 31 is pressed against the continuous portion 103 of the workpiece W.

First, the crest of the internal gear is first formed at the root portion 20.
4 is formed. This step is shown in FIG. As shown in the drawing, the work W is sandwiched between the rotary inner die 1 and the presser die 2 and attached, so that the peripheral wall 102 of the work W is fitted to the rotary inner die 1. At this time,
The forming roller 3 is retracted to a position away from the rotary inner mold 1.

The work W is rotated together with the inner rotary mold 1, and the molding roller 3 is moved closer to the inner rotary mold 1. Forming roller 3
When the inclined forming surface 31 contacts the continuous portion 103 of the work W, the forming roller 3 starts to rotate with the work W.

Forming roller 3 rotating with work W
Is further approached to the rotating inner mold 1, the inclined molding surface 31
Presses the continuous portion 103 of the workpiece W toward the rotary inner mold 1 at a fixed position. As a result, the flow of the meat in the continuous portion 103 of the work W starts, and in the portion corresponding to the open one end portion 14 of the recessed space 11, the meat of the continuous portion 103 falls within the diameter of the rotary inner mold 1. The flesh flowing in the direction and the axial direction, and the flesh flowing in such a manner enters the concave-shaped space 2, thereby increasing the thickness of the continuous portion 103. On the other hand, at a portion corresponding to the convex portion 12 of the rotary inner mold 1, the convex portion 12 protrudes between the meats flowing into the concave forming space 2, so that the continuous portion 103 of the work W is protruded. The portion corresponding to the portion 12 is reduced in thickness. Work W after performing this step
Of the peripheral wall 102 is in a state of being inclined so as to expand forward.

FIG. 4 shows that the flesh flowing into the open end 14 of the recessed space 11 of the rotary inner mold 1 is filled with the recessed space 1.
1 shows a state in which one end portion 14 is completely buried,
The arrow a in the figure represents the pressing direction by the forming roller 3. As described above, when the one end portion 14 of the recessed space 11 is filled with the meat flowing from the continuous portion 103 in the work W, the meat filling the recessed space 11 is shown in FIGS. Only the root 204 of the ridge 202 of the internal gear 200 is formed first. In the illustrated embodiment, the peripheral wall 1 on which the root portion 204 of the peak 202 is formed
02, the axially open end face 20 of the peak 202
The step of molding the end including 5 is performed. This step is shown in FIGS.

In this step, the rotary inner mold 1 described above is
Are combined with each other. The forming roller 4 has a tapered inclined shape-preserving surface 42 at one end of a regular cylindrical forming surface 41, and a ring-shaped flange-forming surface slightly protruding in the radial direction at the other end of the forming surface 41. 43. The forming roller 4 is movable in a direction perpendicular to the axial direction with respect to the rotating inner mold 1, and is moved from a position away from the rotating inner mold 1 to a direction gradually approaching during molding. In this embodiment, the flange forming surface 43 of the forming roller 4 is provided with an annular member 4 provided integrally with the forming roller 4.
A is formed by the outer peripheral surface.

The distal end 104 of the peripheral wall 102 of the work W attached to the rotary inner die 1 faces the cylindrical surface P2 of the rotary inner die 1. From this state, when the forming roller 4 approaches the rotary inner mold 1 as shown by an arrow b in FIG. 5, the flange-formed surface 43 is attached to the tip 104 of the peripheral wall 102 inclined to the tip of the work W. And the forming roller 4 starts to rotate with the work W.

Forming roller 4 rotating with work W
Is further approached to the rotating inner mold 1, the tip 1 of the peripheral wall 102 pressed by the flange forming surface 43 of the molding roller 4.
The outer peripheral surface 15 of the rotary inner die 1 in the region where the concave forming space 11 is not formed, and the outer peripheral surface 15 and the flange forming surface 43 sandwich the distal end portion 104 of the peripheral wall 102 of the work W.

Further, when the forming roller 4 approaches the rotary inner mold 1 as indicated by an arrow c in FIG. 6, the flange-formed surface 43 presses the peripheral wall 102, and the wall of the peripheral wall 102 comes into contact with the flange-formed surface 43. It flows outward through the gap with the cylindrical surface P1, and the flange forming surface 43 bites into the peripheral wall 102, thereby restricting the flesh of the peripheral wall 102 from flowing outward through the gap. For this reason, the phenomenon that the flesh of the peripheral wall 102 flows outward from the gap between the flange forming surface 43 and the cylindrical surface 102 and escapes is suppressed. The tendency to flow in increases.

Thereafter, the molding roller 4 is further moved by an arrow d in FIG.
When approaching the rotating inner mold 1 as shown in FIG.
The flesh of the peripheral wall 102 flowing into the recess 1
The other end 16 of 1 is completely filled. As described above, when the other end portion 16 of the recessed space 11 is completely filled with the flesh flowing from the peripheral wall 102, the internal gear 200 shown in FIGS. Mountain 20
An end including two axially open end surfaces 205 is formed. At this time, the ridge open end forming surface 13 of the rotary inner mold 1 is
It is useful for finishing the axially open end face 205 of the 02 with high precision without causing so-called “sagging” or “burrs”.

At this time, at a location corresponding to the other end 16 of the recessed space 11 of the rotary inner mold 1, the wall of the peripheral wall 102 flows into the recessed space 11 and the peripheral wall 10
2 is increased, and at a portion corresponding to the convex portion 12 of the rotary inner mold 1, the convex portion 12 protrudes between the meats of the peripheral wall 102 flowing into the concave forming space 11. 1
02 is thinned.

Thereafter, the remaining portion of the ridge 202 of the internal gear 200 is formed. The remaining portion of the mountain portion 202 is formed by pressing the peripheral wall 102 of the work W toward the rotary inner mold 1 and causing the wall of the peripheral wall 102 to flow into the concave molding space 11, thereby forming the peripheral wall 102 into the concave molding space 11. This is performed by increasing the thickness of the peripheral wall 102 at the location corresponding to the convex portion 12 while increasing the thickness at the location corresponding to. That is, when the molding roller 4 approaches the rotary inner mold 1 as indicated by an arrow e in FIG.
The effect of maintaining the shape of No. 3 is exhibited. At the same time, the axially intermediate portion of the peripheral wall 102 is pressed by the regular cylindrical molding surface 41, and the flesh flows toward the concave forming space 11 of the rotary inner mold 1, and the concave forming space 11 is Completely filled with 102 meat. Thereby, the concave forming space 11 of the rotary inner mold 1 is formed.
The wall of the peripheral wall 102 flows toward the recessed space 11 to increase the thickness of the peripheral wall 102, and the portion corresponding to the convex portion 12 of the rotary inner mold 1 has the convex portion 12. Is the peripheral wall 102 which has flowed into the concave-shaped space 11.
, The peripheral wall 102 is reduced in thickness.

With the above, the molding of the crest 202 of the internal gear 200 is completed, and the meat filling the concave forming space 11 is shown in FIG.
1 and the ridge 202 of the internal gear 200 shown in FIG.
It becomes 3. In addition, the excess wall sagging portion generated in the process described with reference to FIGS. 5 to 8, that is, the peripheral wall 102 that protrudes between the flange forming surface 43 and the outer peripheral surface 15 of the rotary inner mold 1.
Is removed by cutting after the mold release.

In the above description, when forming the crest 202, the base portion 204 of the crest 202 is first formed, then the end including the axially open end surface 205 of the crest 202 is formed, and Although the method of forming the intermediate portion has been described, on the contrary, the end portion including the axially open end surface 205 of the peak portion 202 is formed first, and then the root portion 204 of the peak portion 202 is formed, Finally, it is also possible to adopt a method of molding the intermediate portion. In short, the root part 2 of the mountain part 202
04 and the axially open end face 2 of the peak 202
The shaping of the end portion including 05 and the shaping of the intermediate portion may be performed in any order.

FIGS. 9 and 10 show another method of forming the end including the axially open end surface 205 of the crest 202 and then forming the remaining portion of the crest 202. in this way,
The forming roller 5 is combined with the above-described rotary inner mold 1 and presser mold 2. The forming roller 5 has a regular cylindrical forming surface 5.
An annular member 5A is integrally provided at one end portion, and an outer peripheral surface of the annular member 5A is a flange-formed surface 53. The molding roller 5 is movable in a direction perpendicular to the axial direction with respect to the rotary inner mold 1, and can be moved during molding.
Is moved in a direction gradually approaching from a position distant from.

When the forming roller 4 approaches the rotary inner mold 1 as indicated by an arrow f in FIG. 9, the flange forming surface 53 comes into contact with the front end portion 104 of the peripheral wall 102 of the work W as shown in FIG. The rotation of the forming roller 5 with the work W starts.

Forming roller 5 rotating with work W
As the arrow g in FIG. 10 further approaches the rotary inner mold 1, the peripheral wall 102 of the work W is closed by the flange-formed surface 53 at a position near the ridge open end forming surface 13 on the side of the rotary inner mold 1. And the meat of the peripheral wall 102 flows into the concave molding space 11. As a result, the peripheral wall 102 is increased in thickness at a position corresponding to the concave molding space 11, and only the end including the axially open end surface 205 of the peak 202 is formed first. Further, when the molding roller 5 approaches the rotary inner mold 1, the regular cylindrical molding surface 51 presses the peripheral wall 102, so that the meat of the peripheral wall 102 flows into the concave forming space 11, Eventually, the concave-shaped space 11 is filled with the flesh to form the remaining portion of the peak 202. As a result, the wall of the peripheral wall 102 flows toward the concave-formed space 11 at the location corresponding to the concave-formed space 11 of the rotary inner mold 1 to increase the thickness of the peripheral wall 102. In the portion corresponding to the convex portion 12, the convex portion 12 protrudes between the flesh of the peripheral wall 102 flowing into the concave forming space 11, so that the peripheral wall 102 is reduced in thickness. At the same time, the front end portion 104 of the peripheral wall 102 is sandwiched between the molding surface 51 and the outer peripheral surface 15 of the rotary inner mold 1, and the excess meat of the peripheral wall 102 is “slacked”.
As a result, the fluid flows outward from between the molding surface 51 and the outer peripheral surface 15 of the rotary inner mold 1.

With the above, the molding of the ridge of the internal gear is completed.
The meat filling the concave forming space 11 becomes the crest 202 of the internal gear 200 shown in FIGS. 11 to 13, and the portion where the protruding part 12 enters becomes the valley 203 of the internal gear 200. In addition,
An excess sagging portion generated in the process described with reference to FIG. 10, that is, a tip portion 104 of the peripheral wall 102 protruding between the molding surface 51 and the outer peripheral surface 15 of the rotary inner mold 1 is cut and removed after the mold release. Is done.

FIG. 11 is an enlarged end view of a main part of a viscous coupling cover C provided with an internal gear 200 formed by the method of the present invention. FIG. 12 is a viscous coupling provided with an internal gear 200 formed by the method of the present invention. FIG. 13 is a cross-sectional view of the cover C, and FIG. The internal gear 200 of the viscous coupling cover C is provided with ridges 202 and valleys 203 alternately at equal intervals on the inner surface side of the peripheral wall 201 and a boss 206 at the center.

[0040]

According to the first aspect of the present invention, the ridge is accurately formed into a shape having no underfill at the end including the axially open end surface, and is finished without requiring skill. This effect is similarly exerted by the invention according to claim 3.

According to the second aspect of the present invention, the peripheral wall of the cup-shaped material pressed at a fixed position toward the rotary inner mold flows outward from the gap between the annular member and the cylindrical surface and escapes. Since the end portion including the axially open end surface of the ridge is formed while suppressing this, the end portion including the axially open end surface of the ridge is more reliably and accurately formed. The same effect is achieved by the invention according to claim 4.

According to the fifth aspect of the present invention, the root portion of the ridge of the internal gear and the axially open end are formed first, and then the intermediate portion of the ridge is formed to form the entire shape of the ridge. Is molded. Therefore, it is possible to accurately finish a ridge having no underfill at any of the root portion and the end portion including the axially open end surface without requiring skill.

[Brief description of the drawings]

FIG. 1 is a partial end view of a material.

FIG. 2 is a partial side view showing an intermediate step for forming a peripheral wall of the cup-shaped material.

FIG. 3 is a partial side view partially showing a final step for forming a peripheral wall of the cup-shaped material.

FIG. 4 is a partial side view showing, in partial cross section, a molding process of a root portion of a mountain portion.

FIG. 5 is a partial side view partially showing a starting step for forming an end portion including an axially open end surface of a mountain portion.

FIG. 6 is a partial side view partially showing a cross section of an intermediate step for forming an end including an axially open end surface of the peak.

FIG. 7 is a partial side view partially showing a final step for forming an end portion including an axially open end surface of the mountain portion.

FIG. 8 is a partial side view showing a step of forming an intermediate portion of a mountain in a partial cross section.

FIG. 9 is a partial side view partially illustrating a first step of another embodiment of the method of the present invention.

FIG. 10 is a partial side view partially illustrating a final step of another embodiment of the method of the present invention.

FIG. 11 is an enlarged sectional view of a main part of a viscous coupling cover having an internal gear formed by the method of the present invention.

FIG. 12 is a cross-sectional view of a viscous coupling cover having an internal gear formed by the method of the present invention.

FIG. 13 is a partial arrow view taken along the line XIII in FIG. 12;

FIG. 14 is an explanatory view of a method that has been attempted to form the ridge of the internal gear.

FIG. 15 is an explanatory diagram showing a defect shape of a ridge in the internal gear formed by the method of FIG. 14;

[Explanation of symbols]

 W Work (cup-shaped material) P1 Gear forming surface P2 Cylindrical surface 1 Rotating inner die 4, 5 Forming roller 4A, 5A Annular member 11 Concave forming space 12 Convex portion 13 Crest open end forming surface 101 Substrate portion 102 Peripheral wall 103 Continuous Installation part 104 End part of peripheral wall 202 Mountain part 204 Root part of mountain part 205 Open end face of mountain part in axial direction

 ──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-53-77869 (JP, A) JP-A-5-76982 (JP, A) JP-A-5-237586 (JP, A) JP-A-5-237586 245578 (JP, A) JP-A-60-96344 (JP, A) JP-A-1-113147 (JP, A) JP-A-4-71749 (JP, A) JP-A-7-256377 (JP, A)

Claims (5)

(57) [Claims] 1. A concave forming space for forming a peak and a convex for forming a valley having a concave opening forming surface at the end for forming an axial open end surface of the peak in the circumferential direction. A cylindrical inner wall is connected to the outer periphery of the substrate part in a rotating inner mold having a gear forming surface arranged side by side and a cylindrical surface axially adjacent to the gear forming surface with the ridge open end forming surface as a boundary. After attaching the provided cup-shaped material so that the tip of the peripheral wall thereof faces the cylindrical surface, while rotating the cup-shaped material together with the rotating inner mold, the peripheral wall of the cup-shaped material is formed on the crest open end forming surface. By pressing the fixed portion against the rotating inner mold side at a position close to the inner wall to cause the wall of the peripheral wall to flow into the concave forming space, the peripheral wall is thickened at a position corresponding to the concave forming space, and the shaft of the mountain portion Only the end including the open end face is pressed, and then the peripheral wall of the cup-shaped material is pressed toward the rotating inner mold The thickness of the peripheral wall is increased by flowing the wall of the peripheral wall into the concave molding space to form the remaining portion of the mountain portion at a location corresponding to the concave molding space. Part formation method. 2. The method according to claim 1, wherein when forming only the end portion including the axially open end surface of the mountain portion, the peripheral wall of the cup-shaped material is formed by the cylindrical surface of the rotating inner die and the annular member which comes into contact with the cup-shaped material and rotates. 2. A sheet metal internal gear according to claim 1, wherein said inner member is sandwiched and said annular member is cut into said peripheral wall to restrict the flow of the wall from flowing outward through a gap between said annular member and said cylindrical surface. Method of forming a mountain. 3. The step of molding only the end portion including the axially open end surface of the mountain portion is performed by forming the end portion in contact with the peripheral wall of the cup-shaped material at a position near the mountain-side open end molding surface and rotating with the cup-shaped material. 2. The method according to claim 1, wherein the step is performed while moving the roller in a direction approaching the rotary inner die. 4. The method according to claim 3, wherein a forming roller integrally provided with the annular member according to claim 2 is used. 5. A concave forming space for forming a mountain portion and a convex portion for forming a valley provided with a mountain open end forming surface at an end portion for forming an axial open end surface of the mountain portion in a circumferential direction. A cylindrical inner wall is connected to the outer periphery of the substrate part in a rotating inner mold having a gear forming surface arranged side by side and a cylindrical surface axially adjacent to the gear forming surface with the ridge open end forming surface as a boundary. After the provided cup-shaped material is attached so that the distal end of the peripheral wall faces the cylindrical surface, while rotating the cup-shaped material together with the rotating inner die, the connection between the substrate portion of the cup-shaped material and the peripheral wall is performed. Press the fixed portion against the rotating inner mold side at a fixed position to cause the meat of the continuous portion to flow into the concave molding space, thereby increasing the thickness of the continuous portion at a location corresponding to the concave molding space. Forming only the root portion on the side of the continuous portion at the mountain portion of the internal gear, While rotating the cup-shaped material together, the peripheral wall of the cup-shaped material is pressed at a fixed position on the rotating inner mold side at a position near the ridge open end forming surface to flow the meat of the peripheral wall into the concave molding space. Thereby, the peripheral wall is increased in thickness at the portion corresponding to the concave molding space to form only the end including the axially open end surface of the mountain portion, and the peripheral wall of the cup-shaped material is pressed toward the rotating inner mold side. By flowing the meat of the peripheral wall into the concave molding space to increase the thickness of the peripheral wall at a location corresponding to the concave molding space and molding the intermediate portion of the mountain, in any order. A method for forming a ridge of a sheet metal internal gear.