JPH08112639A - Formation of outer gear with chamfer - Google Patents

Abstract

PURPOSE: To integrally form an outer gear with chamfer simultaneously with a flat plate blank after forming the flat plate blank thick in the outer peripheral edge thick wall. CONSTITUTION: The flat plate blank 1 is formed to have a predecided diameter by the plate press working, and the inner part is formed into a disk shape and this plate is drilled by a blanking process 3. Successively, a thickening working is executed to the outer peripheral edge part form a thick wall 4. Further, after simultaneously executing the outer gear and the chamfer works by the press working to the outer peripheral edge thick part 4, the finish work 6 is executed to the end surface of the formed tooth part 5. Thus, since the press working is executed to the whole workings except the finish work, welding work is omitted and the manufacturing process can be shortened, thus the workability and the productivity are improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming an external gear with a chamfer by integrally forming an external gear with a chamfer in a forging process using a flat plate material.

[0002]

2. Description of the Related Art A starting gear (drive plate, starter gear) of an internal combustion engine is fixed to a crankshaft side, and a drive pinion fixed to a starting motor side is secured to a part of an outer periphery of the starting motor when the starting motor is driven. It is necessary to ensure smooth meshing and, on the contrary, disengage meshing with the drive pinion when the starting motor is stopped. For this reason, a chamfer is integrally formed on the drive plate of this type so that the drive pinion can be smoothly meshed with the external gear. Furthermore, in order to reduce the weight of this drive plate, a disc (disk) press-molded material using a flat plate material and a ring gear are manufactured separately, and the disk and ring gear are welded together as one unit. There is. This ring gear is made by winding a wire or thin rod material in a spiral shape, cutting it into a ring shape, welding the cut parts facing each other to form a ring shape, and then machining the outer peripheral surface of this ring by machining with a lathe or the like. Cut the gears, then
A chamfer is similarly machined on either side of the external gear. Further, in order to impart a predetermined hardness and wear resistance to the chamfered external gear, the outer peripheral portion of the external gear is hardened by high frequency after cutting and forming the tooth portion.

[0003]

Therefore, it is necessary to separately manufacture the ring gear formed by machining and the disc pressed, and further, the welding work is required when forming the ring gear and when integrating the ring gear and the disc. For this reason, heat distortion due to welding is likely to occur, and it is necessary to separately perform external gear forming using a lathe and chamfering, which requires a great deal of manufacturing work, and there is a problem in terms of productivity and cost.

An object of the present invention is to form an outer peripheral edge of a flat plate material to a thick wall, and then simultaneously forge an external gear with a chamfer by forging.

[0005]

SUMMARY OF THE INVENTION The present invention has been made to achieve the above object, and has a concavo-convex shape for flat plate material to have a predetermined diameter by sheet metal stamping and a predetermined strength inside. A ring-shaped rib is formed into a desired disc shape so that it is integrated, a blanking process is used to make holes, and then the outer peripheral edge is formed into a thick wall by spinning molding. The gist is to perform the external gear and chamfer processing at the same time by press molding on the meat portion, and then finish the end surface of the molded tooth portion.

[0006]

[Function] A flat plate material having a plate thickness suitable for the drive plate is used to press-form an internal shape having an uneven ring-shaped rib so as to have a required diameter and a strength that does not deform due to a rotating torque. After blanking this disc material, thickening is integrally formed on the outer peripheral edge by thickening, and the teeth of external gear and chamfer are simultaneously press-formed (forged) on the outer peripheral surface of this thickening. ), The end face of the tooth portion is finished, and the outer peripheral portion of the external gear is quenched with high frequency as required. For this reason, since everything except the finishing process is formed by press molding, the welding work can be omitted and the manufacturing process can be shortened, the workability and the productivity can be improved, and the manufacturing unit price can be reduced as compared with the conventional case. Further, since the tooth part is formed by cold forging, warming, or hot forging, the metal fiber is not cut, so that the strength is higher than that by the gear cutting method.

[0007]

EXAMPLE A method for forming an external gear with a chamfer according to the present invention will be described below with reference to the illustrated example. First, a flat plate material 1 is used to obtain a disk-shaped material 2 by press molding so as to have a required outer diameter in accordance with the diameter of a drive plate to be completed and thickening the same. Carbon steel (S35C or more) is used as the flat plate material 1, and a plate thickness of 2.3 mm or more is determined according to the drive plate diameter, engine starting torque, or the like.

When the disc material 2 obtained from the flat plate material 1 is press-formed into a disk shape, at the same time, as shown in the figure, a ring-shaped concavo-convex shape is provided so as to have strength to withstand the rotational torque of the drive plate and the like. The reinforcing rib of is molded integrally. This is done by normal sheet metal pressing.

After the sheet metal stamping, the disc-shaped material 2 is punched by blanking, but this can also be performed simultaneously by the sheet metal stamping in the previous step. In this way, the disk portion is molded.

Next, while the central portion of the blanked disk material 3 is clamped from both sides by a mold and rotated, a molding roller is pressed against the outer peripheral edge of the disk material 3 to perform thickening processing. The thick portion 4 is integrally formed on the outer peripheral edge of the. As shown in FIG. 6, this thickening process is performed in 2 to 3 steps by using two or more types of molds K1 to K6 and forming rollers R1, R2 and R3 having different forming shapes.

For example, in the embodiment shown in FIG. 6, molding is performed in three steps. First of all, form K on both sides of the center of the disk material 3.
While sandwiching with 1, K2, on the outer peripheral edge of this disk material 3,
The first forming roller R1 having the narrow groove is pressed and brought into contact. As a result, the peripheral edge of the disc material 3 becomes slightly thicker. Next, using the second molds K3 and K4 whose disk portion has a molding size, while sandwiching and rotating from both sides of the disk material 3 molded in the first molding step, the second molding roller R2 having a wide groove is provided. Press and contact. Thereby, the thick portion is enlarged in the width direction. Next, a third die K5 having a thick portion forming groove on the outer peripheral portion thereof is arranged so that the thick portion is shaped into a shape capable of forming a tooth portion.
While holding the disk material 3 from both sides and rotating it with K6,
The third molding roller R3 for finishing without grooves is pressed against the outer peripheral surface to form the thick portion 4 having a predetermined shape.

This thickening process is performed by forming the disk portion on the left side as shown in FIG. 4 or on the right side as shown in FIG. In addition, the width and height of the thick portion 4 (thickness in the radial direction) by this thickening process
Is determined by the torque resistance and shape of the external gear to be formed. In the illustrated embodiment, a molding outer diameter of 300 mm and a plate thickness of S35C carbon steel of 2.3 mm are used.
It is molded in three steps using a mold and a molding roller so that the width is 10 mm to 15 mm and the height is 5 to 10 mm. At this time, the inner peripheral diameter of the thick portion 4 is determined by the molds K5 and K6, and the outer peripheral diameter thereof is determined by the forming roller R3 so as to have a predetermined finishing dimension.

Further, in the thickening process by the two or three steps, in order to perform the plastic deformation in a thick-walled state more smoothly and with high accuracy, a first mold and a molding roller are used as necessary.
Annealing at a low temperature around 600 ° C. once or twice between the forming step and the second forming step, or between the second forming step and the third forming step, or between each forming step. In some cases, processing is performed to remove stress.

After the thick portion 4 is formed on the outer peripheral edge of the disk in this manner, the thick portion 4 is forged to simultaneously form the tooth portion 5 of the external gear and the chamfer formed on this one side surface portion.
Simultaneous processing of the tooth portion and the chamfer is performed by using a mold 7 as shown in FIGS. This mold 7 is the lower mold mount 7
1. A knockout pin 72 is slidably supported in the center of the upper surface of 1 and an outer gear with a chamfer is fitted with a ring-shaped nib 73 provided with a seizure tooth forming mold 73a on the outer periphery of the knockout pin 72. A punch 75, which is fixed to the lower die mount 71 by a die outer 74, faces the knockout pin 71, and sandwiches the disk material 3, is fixed to the upper die mount 77 via a punch holder 76. A work pressing ring 78 is slidable in the vertical direction on the outer periphery of and is fitted and supported.

In order to form the external teeth 5 with chamfer on the outer peripheral thick wall portion 4 of the disc material 3 with the die 7 constructed in this way, the disc material 3 is placed on the knockout pin 72 and the upper die When the punch 75 of is lowered, the work holding ring 78
Both descend. The lowering of the punch 75 also pushes down the knockout pin on the lower side against the spring pressure, and the lower end of the knockout pin contacts the lower die mount to prevent the lowering. Further, when the tip (lower end) of the work pressing ring 78 comes into contact with the thick portion 4 due to the lowering of the punch, the lowering of the work pressing ring 78 is stopped by this,
When the punch 75 descends further, the work clamp ring 78
The gap C between the upper end of the punch holder and the lower surface of the punch holder 76 is eliminated, and the work holder ring is also pushed down by the punch holder together with the punch.

When the work holding ring 78 descends inside the nib 73, a tooth portion forming die 73a formed on the inner peripheral surface of the nib simultaneously forms an external gear and a chamfer. This is because the tooth forming die 73a has a shape in which the external tooth shape and the chamfer are integrated. At this time, burrs are formed on the work holding ring side in the external tooth portion with the chamfer.

In this way, after the tooth portion and the chamfer are simultaneously formed by forging the thick portion, both end faces in the longitudinal direction of the tooth portion, that is, the tooth end faces are subjected to a finishing process 6 by machining such as a lathe. The burr generated during forging is removed by grinding.

When the outer tooth portion and the chamfer are simultaneously formed by forging, if the drive plate diameter is a small diameter of 200 mm or less, can it be formed by cold forging, or if the drive plate diameter is larger than this, medium or large diameter. In this case, when cold forging cannot be performed with high precision, warm or hot forging is used.

After forming the tooth portion, if the tooth portion has a required hardness, the product is used as it is, or if it is necessary to further improve the wear resistance, the outer peripheral surface of the tooth portion is hardened by high frequency. It is something to do.

[0020]

According to the method for forming an external gear with a chamfer of the present invention, a flat plate material is formed into a disc shape by sheet metal press working, and after punching, the outer peripheral edge portion is formed into a thick wall by spin forming. Furthermore, after the external gear and chamfer processing are performed at the same time by press molding, the end surface of the molding tooth portion is finished, so it is possible to form everything by forging except for finishing, so productivity and work It has advantages such as improved productivity and mass production of highly accurate products. Since the external gear and the chamfer process are cold-forged and formed in the thick portion of the outer peripheral edge, the strength of the tooth portion can be increased without cutting the metal flow. Since the external gear and the chamfering process is forged in the thick portion of the outer peripheral edge while warm or hot, a large-diameter drive plate can be easily manufactured with high precision. Since the induction gear is hardened to the chamfered external gear formed in the thick portion of the outer peripheral edge, the strength of the tooth portion can be easily increased.

[Brief description of drawings]

FIG. 1 is an explanatory view showing an example of a method for forming an external gear with a chamfer according to the present invention.

FIG. 2 is a front view of an external gear formed according to the present invention.

FIG. 3 is a sectional view of the same.

FIG. 4 is an explanatory view showing a thickening processing step.

FIG. 5 is a cross-sectional view of a forging die for processing a tooth portion with a chamfer.

FIG. 6 is an explanatory view of forming a chamfered tooth portion in a thick portion using the forging die shown in FIG.

FIG. 7 is a cross-sectional view of another example of a forging die for processing a tooth portion with a chamfer.

8 is an explanatory view of forming a chamfered tooth portion in a thick portion using the forging die shown in FIG.

[Explanation of symbols]

 1 flat plate material 2 disc-shaped material 3 blanked disc material 4 thick part 5 chamfered tooth part 6 finishing 7 mold for forming chamfered tooth part K K mold for thick part molding R Forming roller

Claims (4)

[Claims] 1. A flat plate material is formed into a predetermined diameter by a sheet metal press working, and the inside is formed into a disk shape. This is punched in a blanking step, and then the outer peripheral edge portion is subjected to thickening processing. Of the external gear with a chamfer, characterized in that the external gear and the chamfer are simultaneously processed by press molding on the thick outer peripheral edge portion, and then the end face of the molded tooth portion is finished. Molding method. 2. The method for forming an external gear with a chamfer according to claim 1, wherein the external gear and the chamfer are press-formed on the thick portion of the outer peripheral edge by cold forging. 3. The method for forming an external gear with a chamfer according to claim 1, wherein the external gear and the chamfer are press-formed on the thick portion of the outer peripheral edge by forging while warm or hot. 4. The method of forming an external gear with a chamfer according to claim 1, wherein induction hardening is performed on the external gear with a chamfer formed in the thick portion of the outer peripheral edge.