JPS6121736B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a press forming apparatus for forming a toothed drum from a single punched disk, and in particular, in a female mold, an arcuate initial shape is formed on the punched disk mounting portion. A drawing hole is provided in succession, an inverted V-shaped intermediate drawing hole made of an inclined straight line is provided in succession to the initial drawing hole, and a cylindrical final drawing hole is formed after passing through the intermediate drawing hole. A preliminary tooth pattern is formed in the continuous portion of the inverted V-shaped intermediate drawing hole and the cylindrical final drawing hole to attenuate in the inverted V-shaped intermediate drawing hole, After passing through the preliminary tooth mold, the drum semi-processed member is introduced into the final drawing hole, and the drum tooth profile is formed using the finishing tooth mold formed on the inner circumferential wall of the semi-finished drum member. To provide a press molding device capable of press molding a high quality toothed drum from a punched disc.

Conventional toothed drums are generally mainly cast products, which have the advantage of producing highly accurate products, but have the drawbacks of poor productivity, being heavy and difficult to handle, and being expensive.

Therefore, the present invention has made it possible to mass-produce the toothed drums by sheet metal press working, and also achieved improvements in productivity and cost while maintaining the planned accuracy through press working. This is what I did.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a toothed drum press molding apparatus of the present invention will be described with reference to drawings showing examples thereof.

FIGS. 1A, B, and C are diagrams for explaining the press-forming apparatus for a toothed drum according to the present invention with its forming order, and FIG. An enlarged longitudinal sectional view of the drum is shown, and FIG. 3 shows an enlarged plan view of a portion of the toothed portion of the toothed drum.

In FIGS. 1A, B, and C, 1 indicates a fixed female mold, and a punching disk 2 is provided at the upper end of the fixed female mold 1.
A flat punched disk mounting portion 3 is formed on which the punched disk is placed, and the central opening of the punched disk placement portion 3 is circular and has an arcuate longitudinal cross-sectional shape. An initial drawing hole 4 is formed, and an intermediate drawing hole 5 is connected to the lower part of the initial drawing hole 4, and the intermediate drawing hole 5 is concentric and has an inverted V-shaped vertical cross-sectional shape made of inclined straight lines. A concentric cylindrical final drawing hole 9 is connected to the lower part of the V-shaped intermediate drawing hole 5, and this cylindrical final drawing hole 5 and the inverted V-shaped intermediate drawing hole 5 are connected to each other. A preliminary tooth forming part 6 whose vertical cross-sectional shape is an arcuate surface is formed on the inner circumferential wall of the continuous part, and a preliminary tooth forming part 6 is provided on the inner circumferential surface of the cylindrical final drawing hole 9. A finishing tooth pattern 8 consisting of alternating concave and convex shapes arranged at equal intervals in the vertical direction is formed, and the preparatory tooth forming section 6 serving as the introduction section thereof has an arc-shaped initial drawing hole section 4 with a tooth height. A preformed tooth pattern 7 is formed in which the damping end portion gradually decreases toward a portion where the diameter is larger than the outer diameter of the drum.

Further, a cylindrical bottom drawing hole 10 is formed at the lower end of the final drawing hole 9 and is concentric with the final drawing hole 9 and has a slightly smaller diameter than the inner diameter of the final drawing hole 9. A step portion 10' is formed at a portion connected to the bottom drawing hole 10, and the lower end of the finishing tooth mold 8 is connected to the step portion 10'.

Reference numeral 12 denotes a movable male mold, and the final drawing hole 9 of the fixed female mold 1 is formed on the outer peripheral surface of the movable male mold 12.
A tooth pattern 13 consisting of alternating concave and convex shapes in the vertical direction corresponding to the finishing tooth pattern 8 formed in the above is formed, and a small diameter bottom drawn portion 14 corresponding to the bottom drawn hole portion 10 is formed at the bottom thereof. has been done.

Reference numeral 16 denotes a movable mold for a cushion which is vertically movably inserted into the female mold 1 and receives the male mold 12 and moves up and down to follow the male mold 12.
A positioning protrusion 17 is formed in the center thereof.

The male and female molds 1 and 12 formed as described above and the movable cushion mold 16 are attached to a press machine as shown in FIG. 1, and first, as shown in FIG. The punched disk 2 is placed on the punched disk mounting portion 3 formed in the above by fitting the hole 2' formed in the center thereof into the positioning protrusion 17 of the movable mold 16 and aligning it. Then, the movable male die 12 is lowered, and the punched disk 2 is subjected to primary preliminary drawing forming along the arc surface of the arc-shaped initial drawing hole portion 4 on the lower surface of the movable male die 12. Then, as shown in FIG. 1B, the movable male mold 12 is further lowered and the movable male mold 12 is moved along the inverted V-shaped inclined linear surface of the intermediate drawing hole 5 which is connected to the lower end of the initial drawing hole 4. Then, the part corresponding to the drum part is subjected to secondary preliminary drawing forming into an inverted truncated conical shape, and the movable male mold 12 is further lowered to form a part corresponding to the inverted V-shaped intermediate drawing hole 5 at the lower part of the inclined surface. Preliminary tooth forming shapes are formed on the inner and outer walls of the inverted truncated conical preformed drum, which is press-fitted into the preliminary tooth molding part 6 and drawn in the inverted H-shaped drawing hole part 5 according to the gradually increasing arc-shaped preliminary tooth mold 7. Then, as shown in FIG. The material is pushed into the tooth mold 13 of the mold 12, and at its lower limit
It is formed into a drum shape as shown in the figure, and a finishing tooth pattern 8 of the final drawn hole 9 is formed on the outer peripheral surface of the drum.
And in the tooth profile 13 of the movable male mold 12, an evenly spaced outer peripheral tooth profile 21 consisting of alternating concave lines 19 and convex lines 20 is formed.
An inner peripheral tooth profile 24 which is in tune with an outer peripheral tooth profile consisting of alternating concave lines 22 and convex lines 23 is formed on the same inner circumferential surface, and at the same time, the lower end of the drum outer circumferential tooth profile 21 is provided with a stepped portion 10' to form a barrel. While forming the portion 18b, the bottom portion of the material is press-fitted into the bottom drawing hole 10 to form the cylindrical drum bottom portion 18a.

The transition to sheet metal drums for toothed drums such as timing pulleys in vehicles has been in recent years.
According to the present invention, high-quality sheet metal toothed drums can be easily mass-produced using a one-motion press using a female mold and a male mold, and the desired product can be provided using a press that is the easiest to manufacture and has the lowest manufacturing cost. promoted.

Draw forming and tooth forming are essential for forming a toothed drum using a one-motion press.
According to the present invention, when the material is introduced into the cylindrical final drawing hole having a finishing tooth profile, it passes through the arcuate initial drawing hole and is then introduced into the inverted V-shaped intermediate drawing hole formed by a linear slope. Preliminary drawing is performed in this manner, and the material is press-formed into an inverted truncated conical shape with a predetermined opening and linear angle by being brought into close contact with the linear slope of the inverted V-shaped intermediate drawing hole, and then subjected to final drawing. At the same time, while forming a preliminary tooth profile on the outer peripheral surface of the inclined rising wall of the inverted truncated conical workpiece using a preliminary tooth profile formed using the inclined straight line of the inverted V-shaped intermediate drawing hole, The female mold and the male mold are essential for press forming of toothed drums, which can be press-fitted into the final drawing hole and introduce the formed drum preliminary tooth shape into the finishing tooth mold to rationally complete the tooth shape. Draw forming and tooth forming using a mold can be performed extremely appropriately, and toothed drums can be press-formed from a single sheet metal with high precision in one motion, making it easy to mass-produce high-quality toothed drums by press-forming. At the same time, it has become possible to provide an inexpensive toothed drum made of sheet metal press.

As described above, according to the press forming apparatus according to the present invention, it is possible to properly and rationally perform tooth forming on the outer peripheral surface of the drum while drawing it into a drum shape using a sheet metal press, and to avoid thick and thin parts, which are a general drawback of press forming. It is possible to produce a sound toothed drum made of sheet metal with sharper tooth edges that can sufficiently withstand long-term use by effectively suppressing the occurrence of defects such as occurrence of tooth profile bending and defective tooth profile bending.

[Brief explanation of the drawing]

The drawings show an embodiment of the invention, and FIGS.
B and C are longitudinal sectional views of the forming apparatus showing the process of press forming the toothed drum, FIG. 2 is an enlarged longitudinal sectional view of the toothed drum, and FIG. 3 is an enlarged plan view of a portion of the drum tooth profile. 1...Fixed female mold, 2...Punching disk, 3...Punching disk mounting part, 4...Circular-shaped initial drawing hole part,
5... Inverted V-shaped intermediate drawing hole, 6... Preliminary tooth forming part, 7... Preliminary tooth mold, 9... Cylindrical final drawing hole, 8... Finish formed on the final drawing hole. Tooth pattern, 12...Movable male mold, 13...Tooth pattern formed on the movable male mold, 18...Toothed drum.

Claims (1)

[Scope of Claims] 1. A molding device for a toothed drum made of sheet metal having a tooth profile parallel to an axis on its circumferential surface, comprising a pair of a female die and a male die, the female die having a punching circle thereof. An initial drawing hole having an arcuate longitudinal cross-section is formed in the central opening of the plate mounting portion, and an intermediate drawing hole having an inverted V-shape and an inclined straight line in longitudinal cross-section is formed at the lower end of the initial drawing hole. A finish in which a cylindrical final drawing hole is provided in succession at the lower end of the intermediate drawing hole, and the cylindrical final drawing hole extends in the vertical direction with tooth heights of the same height. At the same time as forming a tooth pattern, a tooth height gradually decreases toward the initial drawing part and a damping part is formed in the continuous part of the cylindrical final drawing hole part and the inverted V-shaped intermediate drawing hole part made of the above-mentioned inclined straight line. A preformed tooth mold whose terminal end reaches a portion having a diameter larger than the outer diameter of the toothed drum is formed by being connected to the finished tooth mold, and the male mold engages with the preliminary tooth mold and the finished tooth mold. A press molding device for a toothed drum characterized by forming a tooth pattern. 2. A cylindrical bottom drawing hole having a smaller diameter than the final drawing hole is connected to the lower part of the final drawing hole via an annular step. invention. 3. The invention according to claim 1, wherein the longitudinal cross-sectional shape of the preliminary tooth mold is arcuate.