JPS61238436A - Manufacture of timing belt pulley - Google Patents

Abstract

PURPOSE:To manufacture a pulley of an excellent accuracy and quality at good working efficiency in manufacture of a timing belt pulley by forming a rough tooth form to a normal tooth form by forging, after forming a rough tooth form provided with excess metal at an external periphery of a cylindrical drum made of a metallic sheet. CONSTITUTION:When a timing belt pulley is manufactured, first either a rough tooth form 1 provided with excess metal at an external periphery or a rough tooth form 1 provided with excess metal by increasing a diameter of the external periphery. Then, since there is a possibility that a sheet thickness of B part is decreased, in order to concentrate an elongation of the sheet to a C part forming a bottom of the tooth form, the sheet thickness of B part is secured by making a metallic punch at a K part as an angled form or reducing a radius of curvature R. Simultaneously, it is so formed as a dimension of E part is narrower and a dimension of F part larger. Then, the punch is replaced by a normal tooth form punch dies, and the E part is forged by expansing with a normal tooth form punch, and by changing the thickness of material of H, I, I a prescribed tooth form 2 is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method of manufacturing a timing belt pulley.

(Prior art) A timing belt pulley is a pulley with rounded (R-toothed) teeth on its outer periphery, on which a timing belt is hung. Since the circumferential length after tooth molding is about 1.45 times the circumferential length of the outer diameter, molding with a mold is impossible, and conventionally a rolling method has been used.

However, with this rolling method, the roughness of the product surface is noticeable, undulations occur on the tooth surface, it takes time to adjust the rolling machine, and if the product is processed continuously for a long time, there will be variations in the accuracy of external dimensions, etc. There were some inconveniences.

(Problems to be solved by the invention) The present invention has been made to solve the above-mentioned conventional problems,
The present invention aims to provide a method for manufacturing a timing belt pulley that improves manufacturing efficiency, precision, and quality.

(Means for Solving the Problem) In order to solve the problem, the present invention provides a rough tooth shape in which extra thickness is provided on the tooth shape on the outer periphery or extra thickness is provided on the tooth shape on the outer periphery with an increased outer diameter dimension. Summary of a method for manufacturing a timing belt pulley, which consists of a forming step and a step of forming the rough tooth shape into a regular tooth shape by changing the thickness of the tooth ridge, tooth bottom, and tooth trace by forging process. That is.

(Example) Hereinafter, the method of the present invention will be specifically explained with reference to the illustrated example. Fig. 1 shows a tooth profile produced by a side cam method etc. Either a rough tooth profile 1 shown in Figure 1 (B) with thickening is formed, or a rough tooth profile 1 shown in Figure 1 (B) with extra thickness is formed by enlarging the diameter of the outer periphery. In this case, the bending radius is increased so that stress concentration is not applied to the tooth pattern 1, and the forming process is performed so that the wall thickness does not change as much as possible (that is, so that no local plate elongation occurs).

As shown in Figure 1 (B), there is a high possibility that the thickness of the B part will sink during forming, so in order to concentrate the elongation of the plate in the 0 part, which is the bottom of the tooth profile, At the same time, in order to secure the thickness of the B part by making the die punch square or reducing the R, the dimensions of the E part are made narrower and the F part is made narrower in order to secure the corner thickness of the D part in the process described later. Consideration should be given to making the part dimensions thicker.

Next, a step of molding the rough tooth shape into a regular tooth shape is performed, but this involves replacing the regular tooth shape punch and using the same mold (not shown) as in the previous step. As shown in Fig. 2, since the R of the D part is small, the above-mentioned E
The part is pressed open with a regular toothed punch and then forged,
Naokak, ■.

Since the predetermined tooth profile 2 is formed by changing the wall thickness of the machining and J, the radius of the shoulder portion can be sufficiently secured. ■.

Changes in the wall thicknesses of M and J can be carried out simultaneously in one step, or can be carried out in two steps or in several steps.

FIG. 3 shows another embodiment of the present invention, which uses so-called umbrella-shaped molding (see Japanese Patent Publication No. 59-12378) and a side cam system. That is, first, the tooth mold 4 is preformed with extra thickness provided on the umbrella-shaped flange surface 3, and then, in the next step, the outer shape of the pulley 6 is formed at the same time as the regular tooth mold 5 is formed. This is what I did. The subsequent process is
This process is carried out in the same manner as the regular tooth molding process in the previous embodiment, and the same mold is used in the previous and subsequent processes.

(Effects of the Invention) As explained above, according to the method of the present invention, a rough tooth shape with extra thickness is formed in the front step, and a regular tooth shape is formed in the back step. The manufacturing process is efficient because both the front and rear steps are performed using the same mold by replacing only the punch. By narrowing the width, it is possible to secure a sufficient radius of the shoulder of the tooth profile, and eliminate local stress concentration during molding, resulting in a timing belt boot that is strong, precise, and of excellent quality. -is can be constructed. Furthermore, compared to conventional manufacturing methods, there are advantages such as higher productivity and cost reduction.

[Brief explanation of the drawing]

Fig. 1 shows one embodiment of the present invention, (a) and (b) are partial cross-sectional views showing a rough tooth profile formed in the previous process, and Fig. 2 is a normal tooth profile. FIG. 3 is a partial sectional view showing the form of the tooth pattern, and FIG. 3 shows another embodiment of the present invention.
A) is a sectional view of a main part showing a molding state in a pre-process, and (b) shows a molding state in a post-process. 1...Rough tooth profile, 2...Regular tooth profile, 3...7 run surface, 4...
... Tooth pattern, 5... Tooth pattern, 6...
···pulley. Patent Applicant: Marujun Seiki Kogyo Co., Ltd. Figure 1 Figure 2 Figure 3 Procedure Amendment Date January 1, 1985 1, Case Description 1985 Patent Application No. 79987 2゜ Name of Invention Timing Belt Pulley Manufacturing method 3, relationship with the case of the person making the amendment Application Name: Kujun Mki Kogyo Co., Ltd. 4゜ Agent address: 1-1-5 Minami-Aoyama-chome, Minato-ku, Tokyo 107
, Date of amendment order (voluntary) (Date of dispatch) Showa, Month, Day 7, Contents of amendment (1) The description and scope of claims are amended as shown in the attached sheet. (2) Same, page 1, line 15, [timing belt pulley] is corrected to ``Sheet metal timing belt pulley J.'' (3) Same, page 1, line 18, ``To manufacture...''"
If you try to mold the tooth shape with a mold, it will be corrected as J. (4) In the same article, page 1, line 20, "It is impossible to mold with a mold" should be amended as follows. (5) Same, page 3, line 20, ``tooth punch'' Correct with r-tooth punch and die J. (6) Same, page 5, line 3, "punch" is corrected to "punch, die." (7) The drawings and Figure 2 shall be amended as shown in the attached sheet. The above claims include a step of forming a rough tooth shape with extra thickness on the outer periphery of the sheet metal circular ram, and varying the thickness of the tooth crest, tooth bottom, and tooth trace part by scattering processing. A method for manufacturing a timing belt pulley, comprising the step of molding a rough tooth shape into a regular tooth shape. 1

Claims (1)

[Claims] A process of forming a rough tooth shape with extra thickness on the outer periphery,
A method for manufacturing a timing belt pulley, comprising the steps of forming the rough tooth profile into a regular tooth profile by changing the thickness of the tooth ridge, tooth bottom, and tooth trace by forging.