JPS6410302B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention (Field of Industrial Application) This invention relates to a method for manufacturing a pulley.

(Prior Art) Pulleys, particularly V-pulleys, are generally manufactured by subjecting a disc-shaped metal plate 20 to press molding and rotation molding, as shown in FIGS. 6a to 6e. That is, the metal plate 20 shown in FIG. 6a is pressed, and the metal plate 20 shown in FIG. 6b is formed.
A bent portion 21 is formed by bending the outer peripheral edge portion of the outer peripheral edge portion downward. Thereafter, as shown in FIG. 6c, the metal plate 20 is rotated while being pressed by a pair of rotation jigs 22 from above and below, and the bent portion 21 is pressed by a rotating pressing jig 23, and a sixth As shown in Figure d, a flange portion 24 is formed to define the profile of the V-pulley. Then, as shown in FIG. 6e, a boss portion 26 formed separately from the metal plate 20 is fitted into the attachment hole 25 provided transparently in the center of the metal plate 20, and the boss portion 26 Attach screw 2 to metal plate 20
7. By fastening, the V-pulley is completed.

Now, when a V-pulley is used, the force generated from the V-belt is not uniformly applied to the entire flat plate portion of the V-pulley, but increases from the inner peripheral edge of the flange portion 24 to the boss portion 26. but,
In the flat plate portion of the V pulley formed as described above, the mounting holes 25
Since the plate thickness up to the outer peripheral edge of the V-belt is uniform, the rigidity corresponding to the force generated from the V-belt cannot be exerted, resulting in a lack of durability and a short service life. In addition, the metal plate 20
Since it is necessary to attach the boss portion 26 formed separately from the mounting hole 25, the number of parts increases,
There are problems in that the manufacturing cost becomes high and the work becomes complicated. This problem also applies to pulleys other than the V-pulley, such as flat pulleys and toothed pulleys.

(Problems to be Solved by the Invention) This invention attempts to solve the above-mentioned problems of lack of durability, short service life, high manufacturing cost, and complicated work. be.

Structure of the invention (means for solving the problems) In order to solve the above problems, this invention
As shown in FIGS. 3 to 5, while rotating the disc-shaped iron material I, a plurality of locations spaced apart from the center of the iron material I are pressed from above to form a boss portion 4, and a peripheral edge portion P. A process of rolling the plate so that it becomes thinner as the plate thickness increases to form the disk part 1, and a process of bending the peripheral edge P of the iron material I downward by press working after this rolling process to form the bent part 8. After this pressing step, a rotation molding step is performed in which the iron material I is rotated while being pressed from above to recess the bent portion 8 from the outside to the inside to form the flange portion 2. It consists of

(Function) As a result of employing the above-described means, the present invention is such that the force opposing the force generated from the belt increases as it approaches from the inner circumferential edge of the flange portion 2 to the outer circumferential edge of the boss portion 4.

Embodiment Hereinafter, an embodiment in which the present invention is embodied in a method for manufacturing a V-pulley will be described in detail with reference to FIGS. 1 to 5.

FIG. 1 shows the entire V-pulley. Reference numeral 1 denotes a disk portion of the V-pulley, which is thicker toward the center. Reference numeral 2 denotes a flange portion formed on the outer peripheral edge of the disk portion 1, and 3 is a V-shaped groove opened outward on the outer peripheral surface of the flange portion 2, and extends in the entire circumferential direction. In addition, 4
is a boss portion that projects from the center of the disk portion 1, and a shaft hole 5 having a keyway is provided in the center thereof.

Now, a method for manufacturing the above V-pulley will be described below with reference to FIGS. 2 to 5.

First, as shown in Fig. 2, a round bar S of unhardened iron is cut to form a disc-shaped iron material I, and as shown in Fig. 3a, this iron material I
is placed on a table T designed to be rotatable. Then, as shown in FIG. 3b, a jig 6 is used to press the iron material I at a plurality of locations at a certain distance from the center of the upper surface. The jig 6 is rotatable about its axis, and a pressing portion 7 is formed on the tapered surface of the conical tip. In the above state, the table T is rotated in the direction of arrow A, and at the same time, the jig 6 is rotated in the direction of arrow B while being held downward. Then, as shown in Fig. 3c, the iron material I is gradually deformed into a flattened shape by the pressure received from the jig 6, except for the center part C, and furthermore, as shown in Fig. 3d, the outer peripheral edge Part P protrudes outward. When this rolling process is continued, as shown in Fig. 3e, the pressed portion of the iron material I becomes flat, and the protruding portion becomes tapered, with the plate thickness becoming thinner toward the outer periphery, forming the disk portion 1. Ru. Further, the center portion C which is not pressed by the jig 6 protrudes upward in a cylindrical shape and becomes the boss portion 4.

After the above-described rolling process is completed, the iron material I is removed from the table T. Then, as shown in FIG. 4, the outer peripheral edge P of the iron material I is pressed and bent in the opposite direction to the protruding direction of the center portion C to form a bent portion 8, and the iron material I is shaped like a bowl. transform into.

After the press working is completed, as shown in FIG. 5a, the iron material I is placed on the lower rotating jig 9 with the bent portion 8 facing downward, and then placed on the upper rotating jig 9a.
While pressing the upper surface of the iron material I downward, both the upper and lower rotating jigs 9 and 9a are rotated. At the same time,
The outer surface of the bent portion 8 of the iron material I is
and press inward using the second pressing jigs 10 and 11. Note that the lower end of the upper rotating jig 9a is formed in a tapered shape that becomes smaller in diameter as it goes downward, and the upper end of the lower rotating jig 9 is also formed in a tapered shape that becomes smaller in diameter as it goes upward. As shown in FIG. 5b, when both rotating jigs 9 and 9a are placed close to each other, these tapered portions form a recess 12 having a substantially horizontal V-shape in cross section. Therefore, the bent portion 8 is pressed downward by the upper rotating jig 9 and inwardly pressed by the first pressing jig 10, and the bent portion 8 is pushed into the recessed portion 12 so that the cross section thereof is almost horizontally V-shaped. The flange portion 2 is recessed in the shape of a flange portion 2, and a V-shaped groove 3 extending in the entire circumferential direction is formed on the outer peripheral surface of the flange portion 2. The second pressing jig 11 is used to bend the lower end of the flange portion 2 downward to provide rigidity to the flange portion 2 during use of the V-pulley.

After the above-described rotational molding process is completed, the boss portion 4 is drilled and the shaft hole 5 is formed therethrough.

In the V-pulley formed as described above, the plate thickness of the disc portion 1 becomes thicker as it approaches the outer peripheral edge of the boss portion 4 from the inner peripheral edge of the flange portion 2, so that it can sufficiently cope with the force received from the V-belt when the pulley is used. It has strong strength.

Furthermore, since the iron material I is formed by cutting the round iron bar S, there is little loss of material and it is very economical.

Furthermore, since iron material I is not hardened, it is highly malleable and can be easily processed.
During processing, frictional heat generated by both the upper and lower rotating jigs 9, 9a and the first and second pressing jigs 10, 11 produces a hardening effect, and the rigidity increases due to work hardening.

Furthermore, since the disk portion 1 and the boss portion 4 are integrally formed, the number of parts is reduced and manufacturing work is also simplified.

Note that the present invention is not limited to the above-mentioned embodiments; for example, two or more V-shaped grooves 3 may be formed in the flange portion 2.

The work of forming the V-shaped groove 3 is omitted from the rotational molding process, and only the flange portion 2 is simply formed to manufacture a flat pulley.

In the rotational molding process, a toothed pulley is manufactured by performing a toothing operation instead of forming the V-shaped groove 3.

Any changes may be made without departing from the spirit of the invention.

Effects of the Invention As detailed above, the present invention rotates a disc-shaped iron material and presses from above at multiple locations spaced apart from the center of the same material to form a boss portion, and furthermore, A process of rolling the plate so that it becomes thinner to form a disk part, a process of bending the peripheral edge of the iron material downward by pressing after this rolling process to form a bent part, and this pressing process. Afterwards, by rotating the iron material while pressing it from above, the bent part is recessed inward to form a flange part, which reduces the service life. This has the excellent effect of making it possible to manufacture a V-pulley that is long, easy to manufacture, and low in manufacturing cost.

[Brief explanation of drawings]

Fig. 1 is a partially cutaway perspective view showing a V-pulley manufactured according to the present invention, Fig. 2 is a perspective view showing a state in which a bar is cut to form a steel material, and Figs. 3 a to e.
is a cross-sectional view showing the step-by-step process of rolling iron material,
Figure 4 is a cross-sectional view showing the state in which the iron material is pressed.
Figures 5a and 5b are cross-sectional views showing step by step how a V-pulley is formed from iron material in the rotational molding process;
Figures a to e are cross-sectional views showing conventional examples. DESCRIPTION OF SYMBOLS 1... Disk part, 2... Flange part, 4... Boss part, 8... Bent part, I... Iron material, P... Peripheral part.

Claims (1)

[Claims] 1. While rotating the disc-shaped iron material I,
A process of forming the boss part 4 by pressing from above at multiple locations spaced at regular intervals from the center of the disc, and further rolling the disc part 1 so that the plate thickness becomes thinner toward the peripheral edge P, and the same rolling process. Thereafter, a step of bending the peripheral edge P of the iron material I downward by press working to form a bent part 8, and after the pressing step, rotating the iron material I while pressing it from above,
A method for manufacturing a pulley comprising a rotational molding step of pressing the bent portion 8 inward to form a recess to form the flange portion 2. 2. The method of manufacturing a pulley according to claim 1, wherein the iron material I is formed by cutting an unhardened round bar material. 3. The method of manufacturing a pulley according to claim 1, wherein the boss portion 4 is provided with a shaft hole 5 transparent therein. 4. The method for manufacturing a pulley according to claim 1, wherein a V-shaped groove 3 is formed in the flange portion 2.