JPS5978737A - Production of plateworked pulley - Google Patents

Abstract

PURPOSE:To make easy mass production of a lightweight and inexpensive plateworked pulley by building up an annular thick walled part in the outside circumferential region of a circular plate and forming an annular corner part for the bottom of a cup-shaped pulley blank material in the thick walled part then subjecting the same to pressing for forming a tooth profile. CONSTITUTION:A circular plate a1 is pressed and a plate b1 built up beforehand with a thick walled part 8 in the outside circumferential region with the part 4b corresponding to a bottom plate 4 decreased in wall thickness is prepd. The plate b1 is then subjected to pressing for deep drawing to form a cup-shaped pulley blank material 1b consisting of a cylindrical part 3b and a bottom part 4d and to form an annular corner part 5b for the bottom of the material 1b with the thick walled part 8, thereby building up excess metals 6b, 6c by the part 8 in the part 5b. The excess metals 6b, 6c are elongated in parallel with the axial direction, i.e., the cylindrical part 3b by pressing for forming a tooth profile whereby a tooth profile 2 is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a sheet metal pulley for a timing belt.

Figures 1A and 1B show sheet metal Boo'J-1, which is the object of the present invention.
shows. As shown in the figure, this sheet metal pulley is formed by pressing a cylindrical part 3 having a rectangular wave-shaped tooth profile 2 on its circumferential surface and a bottom plate part 4 covering an opening on one side of the cylindrical part 30. That is, the -]2 sheet metal pulley is made by punching out a single circular plate a as shown in Fig. 2A, and applying deep drawing press processing to this circular plate A, as shown in Fig. 4B. The bowl-shaped sheet metal pulley material lat is made by pressing the cylindrical part 3a of the bowl-shaped sheet metal pulley 1a into a tooth forming shape.It can be easily mass-produced from plate material by pressing, and is lightweight and inexpensive. For some reason, it has come to be widely used as a timing belt pulley in vehicles.

However, while the above-mentioned sheet metal goo IJl has an advantage in layout, when deep drawing press processing is performed on a thin plate, the connection between the cylindrical part 3a and the bottom plate part 4a of the bowl-shaped sheet metal pulley 18 as shown in FIG. It is considered inevitable that a thinning phenomenon (reduction in plate thickness) will occur in the installed portion, that is, the bottom annular corner portion 5a.

In the figure, 6a shows a corner thinned portion caused by the L thickness shrinkage.

Thus, the above-mentioned bowl-shaped sheet metal pulley element 11' 3a is subjected to tooth forming press processing to form a tooth forming shape from the bottom annular corner portion 5a toward the end of the cylindrical portion 3a (the pressing direction is indicated by an arrow in FIG. 3). When press working is performed, the same corner part 5
Since there is insufficient plate thickness (existence of thin corner part 6a) for the plastic working of the grooves in a, stress concentration occurs in the same area, and the elongation of the grooves is larger than in other areas. After molding, the thin wall portion 6 of the corner portion 5 is formed as shown in FIGS. 4 and 5.
The wall thickness of a becomes thinner and thinner (6 indicates the corner thinner part after the same tooth preparation shape), causing a fracture, or even if it does not result in a fracture, a noticeable turf of the tooth profile is caused, and the effective tooth length becomes too small. This results in problems such as a decrease in the rigidity of the pulley.

When a pulley with such a thin body is used for transmission by a belt, stress is concentrated at the corner part due to the load (because it has a cantilevered structure), so it may crack or break during use. In addition, a decrease in the number of effective teeth (rl) may abnormally increase friction, shorten the belt life, or cause deviation during belt drive.

The drawbacks of the above-mentioned sheet metal pulley become more pronounced as the tooth height of the tooth profile increases, and for this reason, it has been difficult to increase the tooth height beyond a certain limit to improve performance.

Therefore, the present invention was devised to fundamentally solve the above-mentioned problems without losing the advantages of the sheet metal pulley, and FIG. 6 and subsequent figures show embodiments of the present invention for the same purpose. shows.

That is, as shown in FIG. 6A, a circular plate a+f, which is thicker than the finished pulley, is first formed by cold forging into a punched plate or a metal block, and then a four-layer plate is formed on the circular plate a+. , 82 As shown in Fig. 82, the play 1, bl or 1db2 is formed by press working to reduce the thickness of the parts 4b and 4c corresponding to the bottom plate 4, and to form a thick part 8 in the outer peripheral area of the circular plate in advance. (H4 is provided.

FIG. 6B+ shows the formation of the thick portion 8 and the bottom plate 4bl.
6B2 shows the case where the portion 4C corresponding to the bottom plate 4 is made flat and the thick portion 8 is raised on one side of the grate.

Next, the play that formed the plate thick part 8) b+ or b2
is subjected to the deep drawing press process described above. The cylindrical part 3b and the bottom plate part 4d are formed by the deep drawing 9 press process as shown in FIG. 6C.
At the same time, the thick part 8 forms the bottom annular corner part 5b of the bowl-shaped pulley part 1b.
I-formed corner part 51) K extra thickness 6 due to the same thick part 8
b'ff: Serve up.

Fig. 6C shows deep drawing 9 forming [7, mainly the bottom annular corner part 5] on the inside of the cylindrical part 3b'.
The inside of b is 6 bi thicker than the above extra meat.''

Reference numeral 6C indicates the extra thickness built up on the outside of the bottom annular corner portion 5b.

As shown in FIG. 6B2, FIG. 8, and FIG.
], press-forming is performed, and the above-mentioned extra thickness 5b, 5c is formed by moving it to the corner portion.

As an example, a cylindrical part 3bi with the thick plate part 8 outside
If deep drawing press processing is performed, 5 ci of extra plate thickness will be added to the outside of the bottom annular corner 5b of the bowl-shaped pulley element tJ'3b.
I can get two.

As another embodiment, FIG. 9 shows that the thick portions 8 are formed on the front and back surfaces of a circular plate, and the deep drawing press process is applied to the inner and outer sides of the bottom annular corner portion 5b.
Indicates a two-digit case.

FIG. 7 shows an embodiment in which extra thickness 6C is built up on the outside of the bottom annular corner portion 5b. That is, the bowl-shaped pulley element 11'l
Prepare a play 1-b3 in which an annular thick portion 8a is formed on the back surface of a disc plate as shown in Figure A as the month of b.
The annular thick portion 8a protrudes only in the vicinity of the molded portion of the mirror annular corner portion 5b, and if the above-mentioned deep drawing press processing is performed with this portion on the bottom side, an extra thickness 6c will be formed on the outside of the annular corner portion 5b of the bottom portion.
can be bulged.

FIGS. 8A and 8B show a forming apparatus for deep drawing press processing of the bowl-shaped Gooley moon 1b. In the figure, 9 is a male mold for molding the inner shape of the bowl-shaped pulley 1b, 10 is a female mold for molding the outer shape, and 11 is a bottom plate part 4d' (i= The sliding mold used to form the bottom is shown.

Said thick portion 8 or sat raised plate b+.

b2 or b8 is supported on the female mold 10 and sliding mold 11, and the male mold 9 is lowered and pushed into the female mold 10 while colliding with the sliding mold 11. As a result, the bowl-shaped pulley 1b is formed. At this time, the thick part 8 or 8d is located at the continuous part (bent part) of the cylindrical part 3b and the bottom plate part 4d,
If a portion is formed at the corner portion of the male die 9 and the sliding die 11 to allow the thick wall portion 8 or 8a to escape, then the extra wall thickness 6b or 6C or both 6b can be obtained.

fart 6C molding is possible.

The thus formed bowl-shaped sheet metal pulley 11 is subjected to tooth forming press processing. This tooth forming press processing method is the 8th
The principle is the same as that of the forming part a of the bowl-shaped sheet metal pulley 1b shown in Figures A and B. That is, it can be considered that the plate (play)b2f2f is replaced with the bowl-shaped sheet metal pulley 1b, a rectangular wave pattern is formed on the peripheral surface of the male mold 9, and a rectangular wave pattern that engages with this is formed on the female mold 10.

In this way, the bowl-shaped sheet metal pulley material 1b is pressed from the bottom annular comber portion 5b toward the end of the cylindrical portion 3b to form the tooth profile 2.

As mentioned above, the bottom annular corner portion 5b of the bowl-shaped sheet metal pulley 1b has an excess thickness 6b or 6c or its 3X direction 5.
b and 5c have been processed in advance, and the tooth profile 2 is formed by stretching the extra thickness 6b or 6c in the axial direction, that is, parallel to the cylindrical portion, in the tooth forming press process.

As a result, the sag at the end of the tooth profile 2 is completely reduced by 7, making it possible to increase the effective tooth length as much as possible, and causing thinning at the corner portion 5a after tooth forming press processing. However, there will be no shortage of board thickness.

Therefore, while taking advantage of the advantages of press forming of sheet metal pulleys,
It is possible to mold the tooth height to be higher without causing a large decrease in the effective tooth length or a decrease in pulley rigidity.

In addition, as described above, the tooth profile 2 is formed soundly, and the formation of the corner thin part 6 of the continuous part (bent part) of the P-shaped cylinder part 3 and the bottom plate part 4, that is, the bottom annular corner part 5b, is suppressed. This ensures stable driving of the belt hooked thereto, and provides a high-quality sheet metal pulley that does not cause the belt to shift to one side or cause premature contact.

As a result, the problems in press working of sheet metal pulleys mentioned at the beginning can be effectively solved and its practicality can be made more realistic.

[Brief explanation of drawings]

Figure 1A is a plan view of the sheet metal boot IJ-, which is the object of the present invention, Figure B is a sectional view taken along the line A-A, and Figure 2A1B summarizes the forming process of a conventional sheet metal pulley. Figure A is a cross-sectional view of the circular plate, Figure B is a cross-sectional view of the bowl-shaped pulley, and Figure 3 is a cross-sectional view of the circular plate.
The figure is an enlarged sectional view of the bottom annular corner part of the same bowl-shaped pulley material, Figure 4 is an enlarged view of the chevron part of the sheet metal pulley formed from the same bowl-shaped pulley material, and Figure 5 is a sectional view taken along the line B-B. Figure 6 and subsequent figures show embodiments of the present invention; Figure A is a cross-sectional view of a circular plate, Figure B1 is a cross-sectional view of a plate with a molded thick part, and Figure B2 is a plate with a molded thick part of another example. cross section,
Figure C is a cross-sectional view of the bowl-shaped pulley, Figures 7 and 8 show the molded side of the thick part of another example, Figure A is a cross-sectional view of the same plate, and Figure 4B is a cross-sectional view of the same bowl-shaped pulley. Figure, Figure 8 AX 8
The figure shows a cross-sectional view of an example of a press-forming device for a bowl-shaped pulley. be. l Sheet metal goo IJ-12...Same tooth profile, 3 Same cylindrical part, 4
Bottom plate part, 5 Bottom annular corner part, 6 Thin corner part, 7 Tie, 8, 8a to thick part, al Disc plate, b+, b2. bg/thick part molding plate, lb
Bowl-shaped pulley material, 3b, cylindrical part, 4d, bottom plate part, 5b... bottom annular corner part, 5b, (3c
Same extra thickness, 9: male type, 10: female type, ii sliding type, inner circular thick part. 8-” Figure 3/゛.

Claims (3)

[Claims] (1) When forming a bowl-shaped pulley by deep drawing press processing (I) on a circular plate, the outer circumferential area of the circular plate is preliminarily filled with a thickness of 9 km. By forming the bottom annular corner part of the bowl-shaped pulley material in the annular thick part, excess thickness is built up in the bottom annular corner part, and the excess thickness is extended to the cylindrical part of the bowl-shaped pulley stack. A method for manufacturing a sheet metal boot IJ-, which is characterized by performing tooth forming press working. (2) In the invention described in item 1, the method for manufacturing a sheet metal pulley is characterized in that the above-mentioned extra thickness is raised inside the bottom annular corner portion. (3) A method for manufacturing a sheet metal pulley according to the invention described in item 1, characterized in that the extra thickness is built up on the outside of the bottom annular corner.