JPH0299236A - Manufacture of endless hoop having metallic teeth - Google Patents

Abstract

PURPOSE:To continuously form a highly accurate tooth profile uniform in pitch by moving a hoop being a stock intermittently at a feed rate of the same pitch as that of a specified tooth profile and repeating plural stages of press-forming at the same position. CONSTITUTION:The hoop 1 is fed between an upper and a lower die 2, 3 inter mittently at the same pitch as that of the tooth profile and forming of plural stages is repeated through plural forming recessed and projecting parts so that each tooth depth increases in sequence to the same positions of the hoop 1. In this way, from the shapes of the dies and the shape of the hoop, the hoop is restrained by the dies larger in tooth depth. Since this restraint moves in sequence toward the dies smaller in tooth depth, the stock retracting in forming the hoop is fed in only the unformed side of the 1st stage of forming where the tooth depth is the smallest. Besides, since the elongation of the stock need not be expected thoroughly, the tooth profile 1a uniform in pitch can be formed continuously and surely all over the peripheral length of the hoop 1.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to the manufacture of metal toothed belts used for the purpose of transmitting power in various industrial machines, automobiles, etc. and adjusting machine operation timing, etc. The present invention relates to a means for manufacturing a metal toothed endless hoop used as a belt element thereof.

(Prior Art) It is well known that a toothed rubber belt has conventionally been used as a timing belt that transmits rotational power with the same Q on the driving side and the driven side. However, it is also known that this toothed rubber belt has many drawbacks, the biggest of which is the problem of heat resistance and elongation of the belt due to thermal expansion. These problems can only be solved by incorporating various reinforcing holes and reinforcing structures into the rubber belt body. In order to solve these problems, metal synchronous power transmission belts have recently been developed. The metal toothed bells 1 to 1 have a belt structure consisting of a flexible endless hoop-shaped thin metal strip with tooth profiles that match those of the driving and driven gears. , e.g. rDEsI
GN ENGINEERING, magazine (US January issue, 1
April 19981 issue, page 63~), or Jitsukai Sho 61-1
As shown in No. 93245 and others, the present inventors have also made various proposals regarding such metal toothed belts, and in manufacturing these belts,
An endless hoop-shaped toothed ribbon having tooth-shaped protrusions with a constant pitch is required as a belt element.

(Problems to be Solved by the Invention) In manufacturing the endless hoop-shaped toothed ribbon having tooth-shaped protrusions with a partial pitch as described above, it is necessary to have a large number of tooth-shaped protrusions with a partial pitch, and to improve the size and accuracy. It is extremely difficult to form it well. That is, common sense suggests that, as illustrated in FIGS. 4 and 5, a flat metal ribbon 50 made of steel strip is used as a material, and this is used as a pressure bonder 52 having tooth-shaped protrusions 51 having a desired cross-sectional shape. On a press molding line having tooth-shaped recesses 53 corresponding thereto, the tooth-shaped protrusions 54 are formed on the metal thin strip 5 by pressing down with a pressure punch 52 and press-forming.
0, when forming the tooth-shaped protrusions 54, as the pressure punch 52 descends, the ribbon 50 to be formed is pulled in from the left and right to form the protrusion. It is extremely difficult to ensure a uniform pulling amount and elongation, and when forming continuous tooth-shaped protrusions 54 over the entire circumference of the ribbon 50, it is difficult to improve the pitch accuracy due to this. The reality is that this is close to possible.

(Means for Solving the Problems) The present invention, in manufacturing such metal toothed endless hoops, has a forming process that enables industrial mass production, specifies the thickness and width of the material thin steel strip, and To form a series of concave and convex surfaces for tooth formation, the material thin steel strip is intermittently fed into a press forming line using a series of upper and lower molds in which the height of each tooth increases in sequence. It is possible to continuously form a tooth profile with a uniform pitch and high precision by repeating the process on the same part so that the height of the peaks becomes higher. Specifically, it is possible to form a continuous tooth profile with a constant pitch. In manufacturing a metal toothed belt using an endless annular metal tooth-shaped hoop formed as a belt element for synchronous power transmission, the thickness of the endless annular metal tooth-shaped hoop is 0.1 to 0.5 mm, When bending the tooth profile on the thin steel strip with a width of 3.0 to 25.4 mm, the tooth profile unevenness is symmetrical, having the same circumferential length as the final tooth profile, and gradually increasing the height of the teeth in the tooth profile. Using a press means with a pair of upper and lower molds arranged in a row, the thin steel strip is intermittently fed into the mold at the same feed amount as the tooth profile pitch, thereby performing multiple steps of press forming at the same location. By repeating this process, a continuous toothed steel strip with the final tooth profile formed at the same pitch is gradually formed, and the steel strip is joined into an endless ring shape. Furthermore, the continuous toothed steel strip is joined into an endless ring shape. In doing so,
By overlapping a part of the hoop-shaped end of the steel strip with an extra length than the required hoop circumference length, at least one tooth profile is overlapped, the overlapping part is cut at the same time, and the cut ends are brought together and welded together. The objective is to form an endless annular tooth-shaped hoop with a required circumference and a constant pitch.

(Function) According to the above-described technical means of the present invention, in FIGS. 1, 2(a) and 2(b), the thin steel strip 1 of the material forming the endless hoop with metal teeth is In addition to using a plate having a specific thickness and width, in the embodiment, the flat thin steel strip 1 has a horizontal top surface a and a horizontal top surface a over the entire circumference as illustrated in FIG. A pair of inclined surfaces.

trapezoidal tooth profile 1a surrounded by b, the inclined surface S, b
For the sake of convenience, a trapezoidal tooth profile 1a surrounded by a bottom face C having the same shape and size as the top face (a) is shown as being formed continuously by being alternately turned upside down. In the present invention, in order to carry out such a forming process, a press forming means using an upper die 2 and a lower die 3 illustrated in FIG. 1 is used. That is, in the upper mold 2, the molding recesses (A+, B+,
cl, pasting) and the lower mold 3, a molding convex portion (Az, R
2, c2Dz) indicate the mold surface of the final tooth profile, and are the same as the shape and dimensions of the target tooth profile 1a. The molding recesses (A1, B,
, C,, D, ) and molded convex portions (82, B2,
C2, Dz), then each molding convex part (C1, Dl, El, F
+) and molded concave portions (CZ, 02.B2.F2), molded four parts (EFl, Gl, lI+) and molded convex portions (B2.Fz, G2, +12 >, hereinafter the first with the lowest tooth height. The forming convex part (K
I, L+, L, N+) and (Kz, LZ
, M2, Nt), a plurality of sets of molded concave portions and convex portions are continuously formed. In changing the height of the tooth, it is easy to change the slope of each inclined surface (a) and (b) successively as shown in FIG. At this time, fix the lower mold 3 and also fix the upper mold 2.
The lower mold 3 can be opened and closed under pressure. In the present invention, the thin steel strip 1 has a thickness of 0.1 to 0.
．． 5 mrn, and the plate width tool is 3.0 to 25.4 mm, and the feeding amount is the same as the tooth profile pitch and the left side when facing the figure, into the upper and lower mold 2.3 as shown in Fig. 1. By feeding intermittently from the inlet toward the exit on the right side of the figure, and repeatedly pressurizing and closing the upper mold 2 to the lower mold 3, between the adjacent molding concave and convex parts, By repeating multiple steps of press forming at the same location on the thin steel strip 1, the final tooth profile can be gradually formed at the same pitch. That is, the thin steel strip 1 is intermittently fed into the upper and lower molds 2.3 at the same pitch as the tooth profile pitch, and the height of the teeth is successively increased at the same location on the thin steel strip 1. By repeating multiple stages of press forming through multiple sets of molding concave and convex parts, the mold is constrained from the direction of high tooth height due to the mold shape and thin steel strip shape. By gradually shifting this constraint toward the lower tooth profile heights, the material is drawn in only from the unformed side of the first stage forming where the tooth profile height is the lowest during thin steel strip forming. There is no need to expect elongation at all, so the elongation is uniform over the entire circumference of thin steel strip 1.
The pitch tooth profile 1a can be formed continuously and reliably. The continuous toothed steel band 11 obtained in this way is
Both ends of the hoop are joined to form an endless annular hoop. Appropriate results can be obtained by using the means shown in Figures 2(a) and 2(b) when processing this endless hoop. can. That is, as illustrated in FIG. 2(a), the continuous tooth-shaped band @ 11 is formed into a hoop shape with an extra length than the required hoop circumference length, and both ends 11a of the steel band 11,
After overlapping at least one peak of the tooth profile 1a of the llb and adjusting the pitch so that they match, the two sheets are cut at the same time by appropriate cutting cutters 13 and 14 at the overlapping portion 12. Both ends 15.1
5 are butted together as shown in FIG. 2(b) and integrated with a welding torch 16 to form the desired hoop body. This ensures that a tooth-shaped hoop with the same pitch as the other parts is obtained.
Welding contents include T■G welding, plasma welding, and EB? @Contact etc. can be freely adopted.

(Example) A suitable example of the method of the present invention will be described with reference to FIGS. 1 to 3.

In the present invention, the thickness and width of the thin steel strip 1 used as the material for the endless hoop are limited to specific values for the following reason.

The reason why the thickness of the thin steel strip 1 is set to 0.1 to 0.5 mm is that when a copper strip thinner than 0.1 mm is used, the amount of plastic deformation at the bending part is small (by pressing This is because the shape fixability during molding is poor, making it difficult to obtain a highly accurate tooth profile.Also, if the plate thickness is thin, the rigidity of the tooth profile will be low, increasing the deformation of the tooth when force is applied to the tooth. For,
The thinness of the plate has the above lower limit. The reason why the maximum thickness was set to 0.5 mm is that when the toothed hoop is wound around two toothed hoops as an endless ring and rotated, the hoop undergoes repeated bending and stretching deformation. Since it is proportional to the hoop thickness, if it becomes thicker than this, the life of the hoop will be significantly shortened due to fatigue due to bending and stretching deformation, and if this point is taken into account, the maximum thickness is 0°5.

In addition, in the present invention, the plate width is set to 3.0 to 25.4 mm, but this is because if the width is narrower than 3 mm, the rigidity in the width direction will be extremely small when force is applied to the toothed part, and the belt Since there is a possibility that torsional deformation will occur in the whole, it is necessary to make the width wider than this. Also, the maximum width is 25.4m
+n is not due to the belt characteristics, but because the pulley width becomes large during use, which occupies a space that is difficult to use in practice. Since this is not possible, this value is set as the maximum.

The upper mold 2 and lower mold 3 for press molding used in the present invention have the same circumferential length as the final tooth profile, and the height of the teeth in the tooth profile is gradually adjusted from the mold entrance side to the mold exit side. When arranging multiple sets of raised tooth-shaped irregularities in series in a vertically symmetrical manner as a mold surface, as illustrated in FIG. 1, AB=CD=EF=GH=IJ=KL=MN (- Inclined surface b) BC=FG=JK (-Top surface a) DE-Old=LM (=Bottom surface C) Satisfies A, B, C, D (In upper mold 2, Δ pasting, cl, ol, In lower mold 3, Az, Bz
, Cz02) is the final tooth profile shape. Set the upper and lower molds 2 and 3 like this, and insert the thin steel strip 1 into the upper and lower molds 2.3 from the population side at the left end toward the exit side at the right end, according to the tooth profile pitch. Feed intermittently at the same pitch, and the first
The molding convex parts (K, , L, , M
l, Nl) and molded recess (K2 +LZ, gate z
, Nz), the molding recess (
AI, B+, self, pasted) and molded convex portion (AzBz
. By performing a press forming operation in which the height of the peaks increases sequentially by opening and closing the upper mold 2 with respect to the lower mold 3, the final tooth profile 1a, which is trapezoidal in the example, is formed over the entire circumference of the FjX steel strip 1.
are successively formed one after another. As mentioned above, according to the press forming method using the lower mold 2.3, the mold is constrained from the side with the higher tooth profile height, and this restraint is sequentially applied to the side with the lower tooth profile height. It will move to.

As a result, the material retraction during forming of the thin steel strip 1 is limited to the forming convex portion (Kl +
Ll, Ml, Nl) and molded recess (K2
, L2, Mz, Nz), and there is no need to recycle the elongation of the material at all, so continuous molding of the tooth profile 1a with a uniform pitch is reliably and easily possible, and these series of presses Since the molding progresses gradually, smooth molding results can be obtained without straining the material. As partially shown in FIG. 2(a) and FIG. 2(b), the product obtained in the above manner is a flat toothed band steel 11 in which the toothed shapes 1a are continuous at a constant pitch.
Therefore, it is necessary to process this into an endless hoop. The process of making this endless hoop is of course free, but
In order to easily obtain tooth-shaped hoops with the same pitch, the means illustrated in FIGS. 2(a) and 2(b) are appropriate.

That is, as shown in FIG. 2(a), both ends 11a and llb of the continuous toothed steel band 11 are formed into a hoop shape with an appropriate extra length than the required hoop circumference length, and both ends 11a and 11
By polymerizing a part of b, at least one or more of the tooth profiles 1a,
After adjusting the pitches so that they match, the central portion of the overlapping portion 12 is cut at the same time using the cutting force caps 13 and 14, and then both cut ends 15.
15 are butted and welded together with a welding torch 16, thereby making it possible to easily obtain an endless hoop with no deviation in pitch. Of course, this hooping means can be freely selected.

In this example, the cross-sectional shape of the tooth profile 1a is shown to be trapezoidal, but this tooth profile is not particularly limited to this, and is applicable to all tooth preparation shapes that cause material retraction during the tooth preparation. It goes without saying that it is possible.

Figure 3 shows examples of each shape of the tooth profile.
In addition to the trapezoidal tooth profile 1b shown in -a), the tooth profile 1b shown in the same figure (3-b), the tooth profile IC shown in the same figure (3-c), and the tooth profile 1d shown in the same figure (3-d) Various shapes can be created, such as.

(Effects of the Invention) According to the present invention, a metal toothed endless hoop, which is used as a belt element of a new innovative metal toothed belt, as a replacement for a toothed rubber belt, which is a conventional timing belt, has been developed. It is excellent in that it allows easy precision and high-quality manufacturing. When manufacturing synchronous power transmission belts, the pitch accuracy of the constant-pitch tooth profile of the metal toothed endless hoop is most important, but it is extremely difficult to achieve such high accuracy using conventional punching methods. In the present invention, over the entire length of the upper and lower molds, a thin button of the material is placed in the molding press line with the unevenness of the tooth shape, which is used to gradually increase the height of the teeth in the tooth profile. By intermittently moving one strip at the same feed rate as the tooth profile pitch and repeatedly applying multiple steps of press forming to the same location on the thin steel strip, high pitch accuracy and high quality can be achieved extremely reliably and easily. The tooth profile is formed, and the bending process during the press process gradually approximates the final shape, resulting in smooth forming without straining the material. By specifying the above, it becomes possible to easily realize a robust and durable endless hoop, and the necessary equipment itself is simple, making it possible to use it as a means of manufacturing high-precision, high-quality endless hoops with metal teeth. It is excellent.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal section and a front view of an embodiment of press forming means in an embodiment of the method of the present invention, FIG.
3 is an explanatory diagram of an embodiment of the same tooth profile, and FIGS. 4 and 5 are explanatory diagrams of conventional punching means. ■...3 steel strip, 1a...tooth profile, 2...upper mold, 3
...Lower mold, A, B, C, D...Final tooth profile forming opening, convex portion, 11...Continuous tooth profile band steel. Ward 3 (3-a) (3-b)

Claims (2)

[Claims] (1) In manufacturing a metal toothed belt that uses an endless annular metal toothed hoop formed into a continuous toothed shape with a constant pitch as a belt element for synchronous power transmission, the thickness of the endless annular metal toothed hoop is 0.1~0.5mm
, When bending the tooth profile on a thin steel strip with a width of 3.0 to 25.4 mm, the tooth profile has an unevenness that has the same circumferential length as the final tooth profile and gradually increases the height of the tooth ridges in the tooth profile. By using a pressing means set with a pair of upper and lower molds arranged symmetrically and intermittently feeding the thin steel strip into the molds at the same feeding amount as the tooth profile pitch, multiple steps of press forming can be performed at the same time. A method for producing an endless hoop with metal teeth, characterized by forming a continuous toothed steel band with the final tooth profile gradually formed at the same pitch by repeatedly applying the process at different locations, and joining the steel band into an endless ring shape. (2) When joining continuous toothed steel strips into an endless ring shape, a portion of the hoop-shaped steel strip ends with an extra length than the required hoop circumference is overlapped with at least one tooth shape, and the overlapping portion is 2. The method of manufacturing a metal toothed endless hoop according to claim 1, wherein an endless annular tooth-shaped hoop having a predetermined circumferential length and a constant pitch is obtained by simultaneously cutting the cut ends, butting the cut ends together, and welding them together.