JPS58220720A - Manufacture of timing belt and double timing belt - Google Patents

Abstract

PURPOSE:To obtain a timing belt having uniform PLD (interval between the center line of tensed body and thread bottom) by a method in which a mold with small hole and an expandible sail cloth with a rough surface are used and excessive fluid rubber is absorbed as flash. CONSTITUTION:A mold M is provided with small holes 0.1-5mm. in diameter and 5-10mm. in depth for trapping of rubber, or slits H in 0.1-2mm. in depth and 5- 10mm. in depth for trapping of strip rubber, formed at projections T and bottoms of grooves G. Then, an expandible sail cloth 1 with a rough surface coated with an adhesive rubber 2 is placed on the mold M, and an unvulcanized tooth-shaped rubber 3 is fitted into the grooves G of the mold M. Then, a tensed rope 4 is arranged with a fixed tension in a parallel manner on the mold M, and an unvulcanized rubber sheet 5 is laminated on and bonded with the tensed rope 4. Then, a hot plate P is pressed on the rubber sheet 5 in the direction of arrow, the inside of the mold M is heated for vulcanization, and thereby excessive rubber flows into the small holes or slits H of the mold M through the fine holes of the sail cloth 1 to form flash R.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a timing belt with uniform PLD (pitch line difference, distance between tensile member centerline and tooth root) and a method for manufacturing a double timing belt.

Recently, fields that require synchronous transmission using timing belts have expanded, and machine designs have become more compact.
Along with this, the usage of multi-axis drives has increased.

However, a timing belt (single tooth) is required for multi-axis drive.
When using a double timing belt, it is necessary to use an idler belt or multiple timing belts, making it difficult to create a compact design, so the need for double timing belts is increasing.

By the way, for both current timing belts and double timing belts, in order to make the PLD"jz uniform, it is difficult to control the process because the thickness of the canvas and adhesive rubber layer attached to the tooth surface has a subtle effect. Requires a complicated process,
This includes the problem of high costs.

In order to solve this problem, some timing belts are provided in which the tooth portions are not coated with canvas, but these belts are not preferred because they cause problems such as early wear of the tooth portions, an increase in the coefficient of friction, and impact resistance. Therefore, although it is an essential requirement to coat the tooth surface of the timing belt,
In particular, it is difficult to maintain the PLD of the belt at a constant level by covering the upper and lower tooth surfaces of the double timing belt with canvas. Attempts have been made to change the thickness of the canvas for the teeth, but changing the thickness of the canvas will have a major impact on the transmission function of the upper and lower teeth, belt life, etc., and in order to maintain 1 dPLD using this method, Since the rubber is vulcanized to about 'a/4', the adhesive strength of the upper surface teeth must be maintained at a high level at all times, which is extremely difficult. Furthermore, together with the canvas thickness, the amount of rubber filling and covering the teeth and tooth troughs becomes uneven during vulcanization, which makes it difficult to make the PLD uniform.As a result, the PLD f: Another possible cause is the need to achieve uniformity, but sufficient measures have not yet been taken to address this issue.

In view of the drawbacks of the conventional manufacturing method as described above, the present invention aims to improve the drawbacks and manufacture a timing belt and a double timing belt with uniform PLD.

In other words, the feature of the present invention is that regardless of the thickness of the canvas covering the tooth surface, or in the case of double timing belts, the thickness of the canvas for the upper and lower teeth can be changed during manufacturing. By providing pores or slits in the mold used and using a coarse elastic canvas, excess rubber that flows during vulcanization flows into the pores or slits and intentionally prevents the surface of the tooth from becoming slit. The objective is to form a uniform PLD by keeping the amount of rubber filling and covering the belt teeth and tooth valleys constant.

Hereinafter, a method for manufacturing a timing belt and a double timing belt according to the present invention will be explained in detail with reference to the accompanying drawings.

1 to 3 are side views showing the manufacturing process of a timing belt, which is the first invention of the present invention. First, in FIG. Projections (T) and grooves (G) are formed alternately at intervals. This +ilB hole or slit is usually cut off from the company air, but it can also be a so-called vent hole that penetrates the mold and communicates with the air.

First, on this mold (M), a coarse stretchable canvas (1) with an adhesive rubber (2) adhered to it and a texture (interstance fi) of approximately 0.5m+n is placed. You can place it in a straight line as shown in the figure, or in a groove (as shown by the dotted line).
0) may be placed along the inside. In addition, the above-mentioned coarse-grained elastic canvas (1) can be made to have a larger weave by reducing the thread density, but this is not limited to this.
) can be made coarse by making pores with a needle-like object to allow excess rubber to flow out. Furthermore, if the canvas (1) is made of thermoplastic/plastic fiber, the pores of the canvas (1) can be made coarse. It is also preferable to use a needle-like object heated to 150 to 300°C to make the holes so that they do not become clogged, or, in the case of non-thermoplastic fibers, to solidify the pores with resin to prevent the pores from forming. It can be said to be a mode. ``Thus, after placing the above-mentioned canvas, next, as shown in Figure 2, an unvulcanized tooth profile preformed with rubber made of green material such as natural rubber, synthetic rubber, or a blend of these materials is prepared. Glue the rubber (3) to the adhesive rubber layer (2) as shown in Figure 3.
, and fit into the groove (G) of the mold via the stretchable canvas (1).

Next, low-elongation, high-strength low/tensile members (4) made of synthetic fiber rope, glass fiber rope, wire strands, etc. are arranged in parallel with a constant tension on top of the tooth formation shape. Further, a seed layer of an unvulcanized rubber sheet (5) of a predetermined thickness is adhered thereon to form a tensile portion, thereby completing the molding process in preparation for vulcanization.

Note that it is usually desirable to mold the tooth rubber and tension portion rubber with slightly larger volumes.

The thus formed unvulcanized belt molded body is then heated by pressing a hot plate (P) equipped with a heating mechanism (not shown) inside in the direction of the arrow in FIG. The inside is also heated by a predetermined heating device, and vulcanization is performed from both sides of the hot plate (P) on the upper surface and the mold (M) on the lower surface.

At this time, unvulcanized rubber sheet) (5), toothed rubber (3
), the adhesive rubber (2) exhibits a fluid state and forms the tensile part (5) and the tooth part (3), but the excess rubber is released from the coarse canvas (1) by the pressure of the hot plate (P). Mold through the hole (M)
(H) into the pores of the
is formed and the vulcanization process is completed.

Next, the wide vulcanized belt molded body obtained in the above molding and vulcanization process is removed from the mold (M), cut into a predetermined width, and a bar formed on the surface of the teeth (3) is removed. By removing (R), the tooth part (3) is formed with a constant amount of rubber as shown in Figure 4.
, a timing belt with a uniform PLD in which a tension portion (5) is formed can be obtained.

The above is the method for manufacturing a timing belt according to the first invention of the present invention.Next, the method for manufacturing a double timing belt, which is the second invention of the present invention, which improves or expands the above-mentioned method for manufacturing a timing belt, is attached. Drawing 5th
This will be explained with reference to FIGS. 8 to 8.

First, in Fig. 5, protrusions (1) are placed at predetermined intervals in the horizontal direction.
A coarse stretchable canvas (1) with adhesive rubber (2) adhered to it is placed on a mold (tit) which is not provided with normal pores or slits and has alternating concavities and depressions (7). Of course, adhesive rubber (
After placing the canvas (f), there is no problem with attaching the rubber layer (2) to the adhesive rubber layer (2). It is inserted into the concave groove (7) of the mold (m) through the stretchable canvas (1), and another adhesive rubber layer' (2) is attached to the entire upper surface of the mold to form an unvulcanized tooth forming shape. The formation is the same as in the method of the first invention.

Next, separately from the tooth forming body, a lower tooth forming body is molded in the same manner as in the first invention shown in FIG. That is, protrusions (T) and grooves (()) are alternately formed at predetermined intervals in the lateral direction, and rubber reservoir pores of the above dimensions are formed on the lower surfaces of the protrusions (T) and grooves (G), respectively. , or a mold with a slit (H) for the rubber reservoir (glue rubber (2) on top of the mold). 3) Further, adhesive-treated low-elongation, high-strength tensile lobes (4) are sequentially arranged thereon to form a lower tooth preparation feature.

In this way, when both tooth preparation features are formed, the fifth
The unvulcanized tooth preparation shape molded in the figure is removed from the mold (m), inverted, and laminated and pasted onto the tensile member (4) of the lower tooth preparation shape with the tooth profile (3) on the back side. , a double timing belt molded body as shown in FIG. 6 is formed.

Then, protrusions (T) and grooves (G) are alternately formed on the inner surface in the lateral direction, and pores or slits (supports) of the required dimensions are provided in the protrusions (T) and grooves (G). The upper mold (M) with its protrusions and grooves facing downward is fitted and placed on the mold (back teeth (3) laminated on top of the mold), and then the molds (M), (M
) and pressurize the upper mold (M) in the direction of the arrow to perform vulcanization. During this vulcanization, the unvulcanized adhesive rubber sheet) (2), (2).

(3) , (3'l and tooth valleys are formed, and at the same time, excess rubber is removed by pressurizing the upper and lower coarse-grained canvas (1),
(1'L pores into each mold (→, (crystal pores or sulin) (H), (H) into Paris (R)
, (R5-+ is formed. After vulcanization, the wide vulcanized double timing belt molded body formed in the above molding and vulcanization process is removed from the upper and lower molds (M) and (M) to a predetermined width. At the same time, by cutting and removing the teeth (3) and the ribs (R) l (R5) protruding from the surface of (3), a certain amount of rubber is formed on the top and bottom of the tensile member (4) as shown in Figure 7. A double timing belt with a uniform PLD is obtained by forming the tooth portions (8), (3') and the tooth root portions which are symmetrical in quantity.

Here, the upper and lower canvas used in the second invention (1)
, (1'l is a coarse stretchable canvas, and it is recommended to use it by making holes with a needle-shaped object or solidifying the pores with resin so that the pores of the weave do not become clogged). This invention is similar to the invention of 1. In addition, surin) (H) and (H) are not necessarily required for both of the pores provided in the mold (M) and the upper mold (M). On the other hand, this pore.

The number of slits is determined by the belt tooth profile, and the number of slits is determined by the belt tooth profile.

The size of the slit is also within the above range, that is, the pore [0,1 to 5
Body φ, depth 5~10, slit size 0°01~
28 width, depth 5-1off++l, determined by belt tooth profile. If the pores are less than 0.1 m/', the rubber will not flow properly, and if the pores are more than 5 cylinders, too much electricity will flow, causing unevenness on the tooth surface after deburring. As in the case of the line □" hole, if the width is less than 0.01 mm, the rubber will not flow properly, and if the width is 2 or more, the amount of rubber flowing will be too large, so it is preferable to have the width within the above range.

Furthermore, the pores and slits may be of a vent hole type that communicates with the air.

As described above, regarding the manufacturing method of the second invention, the upper and lower tooth portions (s)
(, 4) is the case of a double timing belt formed in symmetrical positions, but during molding, the position of the upper tooth formation shape is shifted and laminated and pasted on the tensile body of the lower tooth formation shape, and at the same time. By shifting the upper mold (crystal) to the above position, fitting, placing and vulcanizing, the upper and lower teeth parts (3), (3') as shown in Fig. 8 are formed.
) is also possible to obtain a double timing belt with asymmetrical.

As described above, in the present invention, coarse elastic canvas, unvulcanized rubber sheet, and unvulcanized toothed rubber are sequentially laminated and fitted onto a mold having pores or slits of predetermined dimensions, and pressurized from the outside.
The rubber is heated to a fluid state, and the excess rubber in this fluid state is passed through the pores of the coarse canvas covering the surface of the tooth portion.

A method for manufacturing timing belts and double timing belts, in which the belt is made to flow through slits to form particles, and belt teeth and tooth valleys are filled and coated with a uniform amount of rubber, and a mold with fine holes is used. However, by absorbing the excess fluid rubber as particles, it is easy to manufacture a uniform timing belt for PLD, and it is also easy to control the process, which is industrially advantageous, and it is possible to reduce manufacturing costs. , the timing belt and double timing belt obtained by the manufacturing method of the present invention are
The excess rubber that flows during the two rounds of molding and vulcanization flows into the pores of the mold and becomes crisp, making it possible to maintain a constant amount of rubber that fills and covers the belt teeth and tooth troughs. Even though it covers the surface of the tooth, it is possible to have a uniform P'LD, and the canvas coating protects the tooth from abrasion +F, + improves impact resistance, and so on. The meshing with the toothed pulley is also extremely good, and it has the feature of being able to perform reliable synchronous transmission, making it suitable for use in multi-axis drives, increasing the transmission force and significantly increasing the belt life, compared to conventional methods. It is much more effective than anything else.

[Brief explanation of the drawing]

1 and 3 are side sectional views showing the manufacturing process of a timing belt according to the present invention, FIG. 2 is a perspective view of toothed rubber used in the manufacturing process of the present invention, and FIG. The figure is a partial side sectional view of a timing belt obtained by the manufacturing method of the present invention, No. 5
6 and 6 are side sectional views showing a method for manufacturing a double timing belt according to the second invention of the present invention, and FIGS.
The figures are side sectional views of various parts of the double timing belt obtained by the second manufacturing method of the present invention. (M) (M) (m)・・・・・・・・・-Mold. (G) (G) <f)) ・・・・・・・・・・・・Concave groove. (T) (T) (t)・・・・・・・・・Protrusion. ((Support) (H)・・・・・・・・・・・・Pore or slit. (R)(R)・・・−・・・・・・ Be, Ri
. (P)・・・・・・・・・・・・・・・Hot plate. (1) (I)・・・・・・・・・・・・Stretchable canvas. (2) (25(2i......Adhesive rubber layer. (3) (3)......Tooth profile part. (4)...・・・・・・・・・・・・・・・Tensile body. Figure 1 Figure 2 Figure 3 j ilj 'jll('j(
,:Figure 4Figure 5Figure 6

Claims (1)

[Scope of Claims] (1) A method for manufacturing a timing belt, characterized in that the following steps (a) to (f) are performed in that order. (b) Using a mold in which protrusions and grooves are alternately formed at predetermined intervals in the horizontal direction, and holes or lateral slits are provided in the protrusions or grooves, adhesive rubber is applied to the mold. The process of placing the pasted rough or perforated elastic canvas. (b) Next, a step of fitting unvulcanized tooth-shaped rubber into the groove of the mold via the elastic canvas. (c) Furthermore, a process of arranging low elongation and high strength lobe tensile members in parallel at a constant tension on top of the above. 2) Next, a step of laminating and pasting an unvulcanized rubber sheet of a predetermined thickness on top of the unvulcanized rubber sheet. (e) A step of vulcanizing the structure molded in steps (a) to (a) above by applying pressure and heating from the outside to obtain a wide vulcanized belt molded body. (f) The step of removing the obtained vulcanized belt molded body from the mold, cutting it into a predetermined width in the longitudinal direction, and removing the notches on the surface of one part of the teeth to obtain a plurality of timing belts. 2. The pores or slits in the mold are 0.1 to 5 mm in diameter and 5 to 1 deep in the former, and 0.01 to 1 in the latter.
Claim 1, which has a width of zwn and a depth of 5 to 10 mm.
A method for manufacturing a timing belt as described in Section 1. 8. The method for manufacturing a timing belt according to claim 1 or 2, wherein the stretchable canvas is coarsely woven with a reduced thread density. 4. The method for manufacturing a timing belt according to claim 1 or 2, wherein the stretchable canvas is a stretchable canvas in which a large number of pores are perforated with a needle-like object. 5. Stretchable canvas surface 5. The method for manufacturing a timing belt according to claim 4, wherein a large number of pores formed in the pores are solidified with a resin to prevent the pores from clogging and clogging. 6. A method for manufacturing a double timing belt, characterized in that the following steps (a) to (f) are performed in the order listed. (a) A step of placing a coarse or perforated elastic canvas with adhesive rubber pasted on a mold in which protrusions and grooves are alternately formed at predetermined intervals in the horizontal direction. (b) Fitting an unvulcanized tooth profile rubber into the groove of the mold via the stretchable canvas, and further adhering another adhesive rubber layer to the top surface thereof to form an unvulcanized tooth forming body. Process. (C) Remove the unvulcanized tooth preparation form from the mold, and place the tooth profile on the tensile body of the unvulcanized tooth preparation form obtained by the steps described in paragraphs 1 (() to (c)). A process of laminating and pasting each other on the back side to form an unvulcanized double timing belt molded body. 2) Alternately forming protrusions and grooves at predetermined intervals in the lateral direction,
and a protrusion of the upper mold having a pore or a lateral slit in either the protrusion or groove of the mold. Step 1 of fitting and mounting the unvulcanized tooth-forming body on the back tooth portion of the above (c) with the groove facing downward. (e) A process of applying pressure and heating to both mold structures (above) from the outside to create a wide vulcanized double timing belt molded body. (f) The obtained vulcanized double timing belt molded body is removed from the upper and lower molds and cut into a predetermined width in the longitudinal direction,
A process to obtain multiple double timing belts by removing pars from the tooth surface. 7. The pores or slits in the mold are 01 to 5 mm in the former case.
, depth 5-10 throats, the latter 0.01-2 throats wide, depth 8,
Stretchable canvas is woven coarsely by reducing the thread density. 9. Stretchable canvas is woven into many pieces using needle-like objects. 10. Numerous pores drilled in the stretchable canvas surface
A method for manufacturing a timing belt according to claim 9.