JPH026294Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a sheet metal poly V pulley, in particular, a roughly cup-shaped preform obtained by processing a metal blank, and small V grooves are formed in multiple stages on the outer peripheral surface of the peripheral wall. The present invention relates to a structure that can effectively improve the strength of a molded sheet metal poly V pulley. In recent years, a so-called sheet metal poly-V pulley has been developed, which is made by carving small V grooves in multiple stages on the outer surface of the peripheral wall (side wall) of a cup-shaped preform obtained by deep drawing a raw metal plate, such as a rolled steel plate. However, in this type of pulley, many small V-grooves must be carved on the outer surface of the peripheral wall, so various methods are required to adopt the conventional method of forming multi-stage V-grooves by bending the peripheral wall. Due to this difficulty, Japanese Patent Laid-Open No. 56-59544, Japanese Patent Laid-Open No. 56-59546, and U.S. Patent No.
4273547, etc., proposes a forming method in which the circumferential wall of the cylindrical molded product is made relatively thick, and then a V-groove is carved by plastic flow on the outer circumferential surface of the circumferential wall. It was also designated as a special public official in 1817.
In Publication No. 55-37331, etc.,
A manufacturing method for poly V pulleys, which falls under the category of conventional bending method, has been clarified, and the applicant of the present application has also proposed the above-mentioned cylindrical forming method by rotational forming method as Japanese Patent Application No. 58-48591. We are proposing a method of forming V-grooves in multiple stages on the outer peripheral surface of the peripheral wall of the product. By the way, such a sheet metal poly V pulley is
Today, automobile fans, pumps, generators,
It is being used to drive air conditioning systems, etc.
Generally, it includes a shallow cylindrical hub portion attached to a rotating shaft, an annular flange wall connected to the hub portion and having an open end on the opposite side of the hub portion, and the flange wall. It has a structure that includes a multi-stage V-shaped groove that opens outward and is formed on the outer peripheral surface of the belt, and a multi-stage V-groove section on which the drive belt is stretched.However, due to improvements in vehicle performance in recent years, In addition, by changing the setting conditions such as increasing the belt tension setting value, higher strength poly V
Pulleys are becoming more and more in demand. In other words, when the set value of belt tension is increased, a larger force will be applied to the attachment part to the rotating shaft, but since the poly-V pulley is made of sheet metal, it maintains sufficient strength. I don't get it,
Therefore, due to lack of strength, the mounting part (hub part) will be destroyed. Of course, in order to solve this problem, it is possible to increase the thickness of the metal plate used in manufacturing such poly V pulleys to increase the thickness of the pulley as a whole. Increasing the overall plate thickness is not only undesirable as it significantly increases the weight of the poly V pulley, but also has inherent problems such as poor workability of the V groove part by spinning etc. and a longer forming time. This was by no means a suitable countermeasure. Furthermore, Japanese Utility Model Application Publication No. 51-61458 discloses a method in which a bottomed cylindrical reinforcing body is fitted onto the hub mounting surface formed at the bottom of the cylindrical part of the sheet metal pulley to hold it in close contact with the hub mounting surface. A new structure has been revealed that can withstand use at high speeds, but it is still not sufficient to reduce the stress that occurs, and the resistance to stress fracture has deteriorated. Further improvements are desired, and there is also the inherent problem of dynamic fretting (occurrence of cracking due to wear caused by minute vibrations). The present invention has been devised in view of the above circumstances, and effectively improves the strength of the poly V pulley while minimizing the weight increase thereof, thereby increasing its durability. The objective is to provide an improved poly-V pulley. In order to achieve such a purpose, the present invention includes a hub portion that is attached to a rotating shaft and has a cylindrical shape with a bottom and a curved bottom corner, and a hub portion that is connected to the hub portion. , a drive belt is stretched, the drive belt having an annular flange wall having an open end on the side opposite to the hub portion, and a multi-stage V-shaped groove opening outward formed on the outer peripheral surface of the flange wall. In a sheet metal poly V pulley having a pulley body obtained by processing a metal blank plate, including a multi-stage V groove portion, the pulley body has a predetermined depth with respect to the bottom outer peripheral surface portion of the hub portion of the pulley body. A reinforcing cap having a cylindrical bottom and a curved bottom corner is fitted into the reinforcing cap, and the inner radius of curvature of the bottom corner of the bottomed cylindrical portion of the reinforcing cap is equal to that of the hub portion of the pulley body. The inner diameter of the opening of the reinforcing cap is larger than that of the outer side of the bottom corner and smaller than the outer diameter of the hub portion, so that the fit connects the bottom of the reinforcing cap with the hub portion. A predetermined gap was formed between the bottom of the base and the bottom of the base. Hereinafter, in order to clarify the present invention more specifically, embodiments of the present invention will be described in detail based on the drawings. First, FIG. 1 is an explanatory cross-sectional view showing the assembled state of the poly V pulley 2 according to an example of the present invention, in which the poly V pulley 2 is mounted on pulley mounting sheets 4 and 6 from both sides. It is sandwiched, fixed with bolts 8, and attached to a rotating shaft 10. This rotating shaft 10 is connected to a fan 14 via a fan coupling spring 12. On the other hand, a belt 16 is stretched around the poly V pulley 2.
By rotationally driving the poly V pulley 2 by the belt 16, the fan 14 is rotated via the rotating shaft 10 and the fan coupling spring 12. By the way, as shown in an enlarged cross-sectional view of FIG. 2, the poly V pulley 2 includes a shallow cylindrical hub portion 20 attached to the rotating shaft 10, and the hub portion. 20 consecutively,
The belt 16 has an annular flange wall 22 having an open end on the side opposite to the hub portion 20, and a multi-stage V-shaped groove 24 that opens outward and is formed on the outer peripheral surface of the flange wall 22. Multi-stage V-groove section 2 to be stretched
It has a pulley body 28 consisting of 6 pieces. This pulley body 28 is obtained by processing a predetermined metal blank according to a conventional molding method.
Here, small V-grooves 24 are formed in multiple stages on the outer circumferential surface of the circumferential wall of a substantially cup-shaped preform obtained from the metal blank according to the rotational molding method described in Japanese Patent Application No. 58-48591. It is formed by molding. The hub portion 20, which has a cylindrical shape with a bottom and is the attachment portion of the pulley main body 28 to the rotating shaft 10, includes:
A reinforcing cap 30 made of a thin plate and having a bottomed cylindrical shape and having a predetermined depth is fitted onto the outer circumferential surface of the bottom portion. In addition, the pulley main body 28 and the reinforcing cap 3
A rust-preventing film is formed on the surface of the poly-V pulley 2 by appropriate treatment, so that the poly-V pulley 2 made of these members will not rust under the environment in which it is used. In addition, in the figure, 3
2 is a through hole through which the rotating shaft is inserted;
Further, 34 is an insertion hole for the bolt 8. Therefore, in the poly V pulley 2 having such a structure, the reinforcing cap 30 is attached to the hub portion 20, which is the attachment portion of the pulley body 28 to the rotating shaft 10, and in the presence of the reinforcing cap 30, As shown in FIG. 1, since the poly V pulley 2 is sandwiched and fixed by the pulley mounting sheets 4 and 6, it is the same as if only the mounting portion was thickened. This made it possible to effectively improve the strength of the attachment part while minimizing the increase in weight. Moreover, in such a structure, since the overall plate thickness is not increased, the poly V pulley 2 can be molded in exactly the same manner as before, which adversely affects its moldability. There is nothing that can be brought about. In addition, the hub portion 20 of the pulley body 28 as shown above
A poly V with a specified reinforcing cap 30 fitted on the
In the pulley 2, if a rust-preventive coating is applied to each member prior to fitting and integrating the members 28 and 30, metal plating treatment is preferably employed. In other words, after subjecting the pulley body 28 and reinforcing cap 30 to a predetermined electroplating process, such as black galvanizing, to form a rust-preventing plating film on their surfaces, these members 28, 30 are It is to make it fit. Incidentally, a typical method for forming this anti-rust film is electrodeposition coating, but if such electrodeposition coating is applied to the pulley body 28 or reinforcing cap 30 before fitting, the coating The film is interposed between the pulley body 28 and the reinforcing cap 30, which causes a reduction in torque, and a decrease in tightening torque causes an increase in stress generated at the mounting part, which deteriorates durability performance. When performing anti-corrosion film forming treatment on the previous members 28 and 30, it is desirable to avoid electrodeposition coating. In the present invention, the fitting structure of the reinforcing cap 30 to the hub portion 20 of the pulley body 28 is as shown in FIG. The radius of curvature (inner R) is made larger than the outer radius of curvature (outer R) of the bottom corner of the hub portion 20 of the pulley body 28, while the inner diameter of the opening of the reinforcing cap 30 is The outer diameter of the reinforcing cap 30 is smaller than the outer diameter of the hub part 20, and a predetermined distance α is formed between the bottom of the reinforcing cap 30 and the bottom of the hub part 20 by fitting them together. It is being done. The structure for fitting the reinforcing cap 30 to the hub part 20 is as shown in FIG. Although it is conceivable to adopt a fitting structure with a gap, such a structure is not sufficient in terms of reducing the generated stress, as is clear from the comparative experiments described below. In short, the hub portion 20 as shown in FIG.
In the case of a fitting structure in which a predetermined slight gap: α is formed between the bottom of the reinforcing cap 30 and the bottom of the reinforcing cap 30, the fifth
As shown in the figure, when they are sandwiched and fixed by the pulley mounting sheets 4 and 6, the pressure contact action of the pulley mounting sheets 4 and 6 against the hub portion 20 and the reinforcing cap 30 is enhanced. can cause favorable phenomena, thereby
The generated stress can now be further reduced. Moreover, by employing the fitting structure as shown in FIG. 3, resistance to stress fracture is improved as described above, and it is also effective against dynamic fretting. In other words, if the outer periphery of the pulley mounting sheets 4 and 6 is not tightly tightened to the bottom of the hub portion 20 or the reinforcing cap 30, wear will occur even due to minute vibrations, and for this reason, the pulley mounting sheets 4 and 6 may not be able to withstand stress. However, in the case of the fitting structure shown in Fig. 3, an effective compressive force is generated by changing the shape of the R of the reinforcing cap 30. Because it has a structure that prevents fretting, it is also effective in preventing fretting. In addition, a predetermined slight gap formed between such bottoms: α
The outer radius of the hub part 20 is 9.5 mm, and the reinforced cap 3
If R is 10.5 mm, it will be approximately 0.1 mm. By the way, regarding the poly V pulley according to the present invention,
The results of investigating the generated stress are shown in FIG. 6. Compared to the conventional product in which the reinforcing cap 30 is not fitted, the comparison product with the reinforcing cap 30 fitted has a certain degree of stress. Although a decrease in the generated stress was observed, a far more significant decrease in the generated stress was observed in both Examples A and B according to the present invention. The comparison product uses a reinforcing cap made of a steel plate with a thickness of 1.0 mm and has a fitting structure as shown in Fig. 4, and the tested products A and B each have a thickness of 1.0 mm.
It has a fitting structure as shown in Fig. 3, using a reinforcing cap made of 1.2 mm steel plate material. In addition, the thickness of the hub portion 20 of all test products was 2.5 mm. In addition, the decrease in tightening torque was investigated by durability tests for poly V pulleys with electrodeposited products (each member was fitted after electrodeposition coating) and a plated product (each member was fitted after black zinc plating). The results are shown in Table 1 below, and as is clear from the comparison in this table, there is almost no decrease in the tightening torque when using the plated product with an initial torque of 100 kg cm. For electrodeposited products, it was observed that the tightening torque decreased to 70 kg·cm after 30 minutes of tightening and further after the durability test. 【table】

Unit: Kg・cm

[Brief explanation of the drawing]

Fig. 1 is an explanatory sectional view showing an assembled state of an example of a poly V pulley according to the present invention, Fig. 2 is an enlarged sectional view of the poly V pulley, and Fig. 3 is a form of fitting of a reinforcing cap to a hub portion. Fig. 4 is an enlarged cross-sectional view of the main part showing an example according to the present invention;
The figure is an explanatory cross-sectional view showing the state when the poly V pulley in the fitting form shown in FIG. 3 is assembled to the rotating shaft, and FIG. 6 is a graph showing the stress generated in various poly V pulleys. 2... Poly V pulley, 4, 6... Pulley mounting sheet, 8... Bolt, 10... Rotating shaft, 12...
...Juan Katsupring, 14...Juan, 16...
... Belt, 20 ... Hub part, 22 ... Flange wall, 24 ... V groove, 26 ... Multi-stage V groove part, 28 ...
...Pulley body, 30...Reinforcement cap.

Claims (1)

[Claims for Utility Model Registration] (1) A hub portion that is attached to a rotating shaft and has a shallow cylindrical shape with a bottom corner formed as a curved portion; an annular flange wall having an open end on the opposite side; and a multi-stage V-groove section on which a drive belt is stretched, which has a multi-stage V-shaped groove that opens outward and is formed on the outer peripheral surface of the flange wall. The pulley body has a pulley body obtained by processing a metal blank plate, and has a bottomed cylindrical shape with a predetermined depth and a curved bottom corner with respect to the bottom outer peripheral surface portion of the hub portion of the pulley body. A reinforcing cap formed as a part is fitted therein, and the inner radius of curvature of the bottom corner of the bottomed cylindrical part of the reinforcing cap is larger than that of the outer bottom corner of the hub part of the pulley body. and the inner diameter of the opening of the reinforcing cap is smaller than the outer diameter of the hub portion, and the fitting provides a predetermined distance between the bottom of the reinforcing cap and the bottom of the hub portion. A poly V pulley made of sheet metal, characterized in that a gap is formed. (2) The pulley main body and the reinforcing cap are
The poly-V pulley according to claim 1, which is characterized in that the poly-V pulley is previously metal-plated before being fitted.