JPS6039906B2 - Method for manufacturing sheet metal pulley with bearing - Google Patents

Description

[Detailed description of the invention] The present invention relates to a sheet metal pulley having a bearing.

Conventionally, a sheet metal pulley has been developed, as shown in Japanese Patent Publication No. 48-41487, in which a bearing iron joint part is formed on the disk part of the sheet metal pulley main body, and a bearing is provided in the bearing competing part.

By the way, sheet metal fu.

-IJ is usually subjected to anti-corrosion treatment, ie, plating treatment, painting treatment, etc., after molding. However, in the case of the above-mentioned sheet metal pulley having a bearing, since the pulley already has a bearing, it is not possible to plate the entire pulley.

Furthermore, even if painting is performed, drying at high heat causes problems such as the IJ gas used in the bearings flowing out, so it can only be dried naturally. Furthermore, it is not possible to perform anti-corrosion treatment to this extent on the bearing mating area. therefore,
The above-mentioned conventional sheet metal pulleys with bearings have poor rust prevention properties, and have a problem that they cannot be put to practical use except under special conditions. Furthermore, in the case of the above-mentioned conventional sheet metal pulley with bearings, as can be seen in the description in the above-mentioned publication, a preformed product is formed, for example, in the shape of a cup and with a bearing group recess provided inside the bottom. After the bearing is iron-fitted in the recess of the preform, the edge of the entrance is contracted into a double wall shape to tightly fix the surface of the bearing, and then the bearing fixing part is inserted into the center of the surrounding wall. After bending it so that it is placed at the center in the direction, a V-shaped groove is formed in the peripheral wall.

However, with this method, when the bearing fixing part is bent to the central position in the axial direction within the surrounding wall, the double-striped opening part that is the bearing fixing part becomes open, and this causes the bearing to loosen in the fixed state. There was a period of obsolescence that resulted in

In other words, according to the conventional method, when the preform is subjected to the steps of fixing the bearing and forming the V-shaped structure, each bent part is affected by the opening effect of the other, so for example, the above-mentioned When forming a V-shaped groove after fixing the bearing,
When the V-shaped configuration was adopted, the fixed portion of the bearing became loose. This invention was made in view of these problems, and its purpose is to provide a bearing that has excellent rust prevention ability and that allows V-shaped grooves to be formed without the risk of loosening the fixed state of the bearing's ironwork. An object of the present invention is to provide a method for manufacturing a sheet metal pulley having the following steps.

In order to achieve the above object, the present invention has a step-bottomed cylindrical body with a small diameter on the bottom side by pressing a steel plate whose surface has been previously treated with anti-rust plating. A step of forming a preform having an inwardly recessed bearing row recess in the center of the wall, iron mounting a bearing in the bearing row recess of the preform, and closing the bearing row recess. The process of tightening the green and fixing the bearing in the bearing assembly recess, and the process of fixing the preformed product in 1
It is loaded between the molding surfaces of a set of rotary molds, and while rotating together with the rotary molds, the distance between the rotary molds of the set is shortened to apply a compressive force in the direction of the axis D to the large diameter peripheral wall of the preform. At the same time, a forming roller is pressed against the outer surface of the peripheral wall to apply an inward bending force, and finally the peripheral wall is formed into a V-shaped groove in close contact with the forming roller and a set of rotary molding surfaces. It is equipped with the following.

An embodiment of the present invention will be described below with reference to the drawings.

First, a surface-treated millet plate that has been previously plated for rust prevention.
For example, an electrogalvanized steel plate (product name: bonded steel plate, reversing, etc.) and a copper-plated steel plate are sequentially pressed in the steps shown in Figure 1 A to D, and are used as a preliminary model for the pulley body A. A molded article A is formed. That is, a single blank plate is first formed into a cylindrical shape with a bottom as shown in Fig. 1A, and then aperture is applied to form a stepped part having a stepped portion a with a smaller diameter on the bottom side as shown in Fig. 1B. A cylindrical body with a bottom is formed, and then, as shown in FIG. 2C, the bottom wall b is recessed inward to form a bearing group concave portion c. Further, as shown in FIG. 1D, a shaft hole e is bored in the center of the bottom wall b of the bearing group concavity c to form a preform A. If necessary, this preform A has a larger diameter. The closed side circumferential twill portion d is cut uniformly and the local twill portion d is shaped. Also,
The above procedure for forming the preform A may be modified as appropriate. Next, the bearing B is iron-fitted into the bearing fitting recess c of the preformed product A formed in this way, as shown in FIG. For example, it is compressed by pressing or by pressing with a forming roller, and the bearing B is fixed in the bearing group concave portion c by the contracted entrance edge f and the green part of the bottom arm b. Subsequently, a V-shaped groove h is formed in the preformed product A, in which the bearing B is fixed as described above, by rotary molding using a molding roller to obtain a completed product. That is, as shown in FIG. 1G, the large-diameter peripheral wall g of the preform A is preliminarily bent inward, and finally the peripheral wall g has a V-shaped cross section as shown in FIG. bend. Here, the entire forming process of the V-shaped groove h described above will be explained in detail with reference to FIGS. 2 to 4.

In the preforming process, as shown in Fig. 2, the preform A with the bearing B attached is loaded between the molding surfaces 2a and 2b of the upper mold la and lower mold lb for preforming so that their axes coincide with each other. do. Upper mold l
The molding surface 2a of a is shaped to be in close contact with the bottom wall surface of the peripheral part of the bearing iron fitting recess c of the preform A, and the molding surface 2a of the lower mold lb
The molding surface 2b is a flat surface that supports the large-diameter opening end of the preform A, and has a flange 3 around it that holds the entrance edge d from the outside. Then, while rotating the preform A together with the upper mold la and the lower mold lb, the distance between the upper mold la and the lower mold lb is shortened so that the large-diameter peripheral wall g of the preform A is aligned in the axial direction. A compressive force is applied, and a preforming roller 4 having a relatively small outer peripheral molding surface 4a with a relatively small curvature is pressed on the outer surface of the peripheral wall g to apply an inward bending force, and as shown in FIG. 1G. The peripheral wall g is bent inward as shown. Note that a retaining ring 6 is inserted into the center of the lower die lb via a spring 5 so as to be biased upward, and the bearing group concave portion c is held from the outside of the bottom with an appropriate elastic force, and the retaining ring 6 A shaft 7 protruding upward from the center of the bearing B is inserted into the borehole of the bearing B, and the preform A is rotated about the shaft 7. In the final molding process, as shown in FIGS. 3 and 4, the preformed product A, which has been preprocessed to form a V-shaped groove, is placed in an upper die 10a for final molding.
and the lower die 10b, with the center of the ball aligned.

The molding surfaces 1 1 a, 1 1 b of the upper and lower molds 10 a, 10 b are conical mirror slopes that fall from the center toward the periphery, and when the upper and lower molds 10 a, 10 b are brought into contact with each other, their A space having a V-shaped cross section is formed between the molding surfaces 11a and 11b. Then, while rotating the preform A together with the upper mold 10a and the lower mold 10b, the distance between the upper mold 10a and the lower mold 10b is shortened to apply compressive force in the axial direction to the peripheral wall g of the preform A. At the same time, the final formed loaf 12 of the pre-processed peripheral wall g is
are gradually and strongly pressed against each other, and finally the bottom wall around the bearing iron fitting recess c comes into close contact with the peripheral wall g, and the peripheral wall g is connected to the forming roller 12 and a pair of rotating molds, that is, upper and lower molds 10 and 10b.
A V-shaped groove h in close contact with each molding surface 11a, 11b, 12a of
It is used to mold. The above-mentioned preforming step in this V-shaped configuration step is necessary when the blank sheet is relatively difficult to process, such as the above-mentioned electrogalvanized steel sheet, and can be omitted if necessary. It is.

Therefore, the sheet metal boule obtained by the manufacturing method of the present invention as described above has a structure in which the bearing B is fixed to the bearing competition part, that is, the drum concave part c provided in the disc part 0 of the preformed product A. Furthermore, since the preformed product A is molded from a rust-preventing treated blank plate, it has sufficient rust-proofing properties without the need for additional rust-proofing treatment after the completion of molding. Incidentally, when this invention was carried out using an electrogalvanized steel sheet, such as Purging (trade name), the amount of plating layer remaining on the product was measured, and the measurement results shown in the following table were obtained.

In other words, although the fly-galvanized layer spreads along the surface of the steel material during roller forming, wears out, and becomes thinner, it does not cause cracks or the like and can sufficiently exhibit the desired rust prevention effect. It was. Therefore, since it is inconvenient to apply special anti-rust treatment during manufacturing, it is possible to improve work efficiency, and also to make sheet metal pulleys with bearings even under conditions where mirrors are likely to occur. It can be made into a practical product that can be fully used. Further, according to the manufacturing method of the present invention, the preform A is a stepped bottomed cylinder with a small diameter on the bottom side, and has a bearing iron fitting recess c recessed inward in the center of the bottom wall b. and the bearing reinforcement recess c
The opening edge f of the bearing competition recess c is fixed to the bearing B which is adjacent to the
The bearing B is fixed as a double close contact part by crimping, and the V-shaped groove h is formed on the peripheral wall g by bending only the outer peripheral side of the entrance edge f of the bearing joint recess c. Therefore, the bearing fixation and the V-shaped configuration can be performed separately and independently, and the machining of one does not affect the bending portion of the other by an opening force or the like.

Therefore, even if, for example, a V-shaped groove is formed after the bearing is fixed, no opening force will be applied to the double close-contact portion of the entrance edge of the bearing lateral recess c that has been previously tightened. There is no possibility that the bearing will come loose in the fixed state.
Therefore, it is possible to reliably and quickly manufacture a high-quality product in which the bearing is securely fixed to the bearing recess c, thereby promoting the practical use of sheet metal pulleys with bearings. It is something. In addition, the processing of the preformed product is relatively small and can be done in a few man-hours, so the work efficiency can be improved.

[Brief explanation of the drawing]

The drawings show an embodiment of the method of the invention, and FIG.
2 through 4 are partial sectional views showing the apparatus and its operation, and FIG. 5 is an explanatory view showing the remaining amount of the plating layer. A. Preformed product, A. ...Pulley body, B...Bearing,
a...Step part, b...Bottom wall, 0...Busk part, c...Bearing iron fitting recess, e...Shaft hole, f...Sekiguchi rim, g...Peripheral wall,
h...V-shaped groove, la, lb, 10a, 10b...rotary mold (upper mold, lower mold), 2a, 2b, 11a, 11b...molding surface of rotary mold, 4, 12--molding roller, 4a , 12a・
・Rocky shore of Deer Ola. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5

Claims (1)

[Claims] 1 By pressing a steel plate whose surface has been treated with anti-corrosion plating in advance, the bottom side is a stepped cylindrical body with a small diameter and is recessed inward at the center of the bottom wall. A process of forming a preform having a bearing fitting recess of the preform, fitting a bearing into the bearing fitting recess of the preform, and crimping the opening edge of the bearing fitting recess to fit the bearing into the bearing. A process of fixing the preform in the mating recess, loading the preform between the molding surfaces of a set of rotary molds, and rotating the mold together with the rotary mold shortens the distance between the rotary molds of the set of the preform. A compressive force is applied in the axial direction to the large-diameter peripheral wall, and a forming roller is pressed against the outer surface of the peripheral wall to apply an inward bending force. 1. A method for manufacturing a sheet metal pulley having a bearing, the method comprising the step of molding into a V-shaped groove in close contact with a molding surface of a mold.