JPH0216694B2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention is characterized in that the upper and lower teeth are evenly arranged and the teeth are uniform.
The present invention relates to a method for manufacturing a double timing belt with PLD (pitch line difference: the distance between the center line of the tension member and the tooth root).

Conventionally, the manufacturing method for double timing belts is as described in Japanese Patent Publication No. 46-22101, in which canvas, tensile rope, an unvulcanized rubber layer, and canvas are sequentially laminated and wound around a grooved inner mold, and the outer surface of the belt is wound. There is a method of forming upper and lower double teeth by inserting a cylindrical grooved rubber matrix into the inner mold and press-curing the rubber layer into the grooves of the inner mold and the matrix. 49−
As described in Publication No. 135056, a previously formed molded unvulcanized rubber sheet was placed in a grooved inner mold, a tensile rope was wound spirally, and the same molded unvulcanized rubber sheets as above were laminated. There are methods such as wrapping a grooved matrix and then vulcanizing it, but in both cases, the matrix is used to form the upper teeth, resulting in uneven alignment of the upper and lower teeth. However, there was a problem in that it was not possible to uniformize the PLD, which requires the highest quality, with a double timing belt.

The present invention is based on the actual state of the conventional manufacturing method as described above,
In view of these shortcomings, we will improve these shortcomings and create a uniform
It is an object of the present invention to provide a method for manufacturing a double timing belt having a PLD and uniformly arranged upper and lower teeth.

That is, the present invention is characterized by sequentially laminating an unvulcanized rubber sheet and rubberized canvas on the back surface of a timing belt (single tooth) that has been molded and vulcanized using a toothed mold, and then attaching the laminated product with grooves. Partial upper teeth are formed continuously on the back of the belt by fitting and clamping with a press mold and applying pressure and heat from the outside, making the arrangement of the upper and lower teeth and PLD of the resulting double timing belt uniform. At the point.

Hereinafter, specific aspects of the method for manufacturing a double timing belt according to the present invention will be described in detail with reference to the accompanying drawings.

First, in the first step in the method of the present invention, as shown in FIG.
A stretchable canvas 1 with unvulcanized rubber of a constant thickness is wrapped endlessly around the outer peripheral surface of a cylindrical toothed mold M in which groups of grooves and grooves G are alternately formed, and then glass fiber, Kevlar ( Trade name: aromatic polyamide),
A low-elongation, high-strength tensile rope 2 such as polyester fiber or steel wire is wound spirally under constant tension, and an unvulcanized rubber sheet 3 of a constant thickness is further wrapped around it to form an unvulcanized belt. The object is to form a molded object.

The thus obtained unvulcanized belt molded body is then vulcanized in the next vulcanization process, but the vulcanization is usually carried out by attaching a cylindrical rubber sleeve (not shown) to the outer peripheral surface of the unvulcanized belt molded body. ), place it in a vulcanization can, and introduce 7 to 8 kg/cm ² of steam into the can.

At this time, the rubber sleeve is heated and pressurized by high-temperature, high-pressure steam toward the center of the mold M, so the unvulcanized rubber sheet 3 exhibits a fluid state and is wound in parallel in the circumferential direction on the mold M. Elastic canvas with rubber 1 below the gap between the rotated tensile bodies 2
flows into the grooves G and G of the mold M while being stretched, forming the lower tooth profile 4 as shown in Fig. 2, and the canvas layer 1, tensile rope layer 2, tooth profile rubber layer 4 and thin back rubber The layers 3' form an integral vulcanized tooth preparation profile.

In addition, in the operation in the above process, the tensile body 2
The unvulcanized rubber sheet 3 to be pasted on top is slightly larger than the amount of rubber in the toothed part 4 in order to completely fill the toothed part 4, so only the excess rubber is left on the back of the tensile member 2. The remainder forms a thin back rubber layer 3'.

Next, the vulcanized tooth forming body is removed from the mold M, and the thin back rubber layer 3' covering the upper surface (back surface) of the tensile member 2 is removed by polishing with a polishing machine such as a grinder or a wire brush. The tensile member 2 is fully exposed, and then wrapped around two toothed pulleys P ₁ and P ₂ whose center distance can be adjusted as shown in FIG. to move to.

Hereinafter, the molding and vulcanization process of the upper toothed portion of the back surface of the tensile member 2 will be explained.

First, adhesive is applied to the two exposed tensile surfaces of the vulcanized tooth-forming body wrapped around the toothed pulleys P ₁ and P ₂ as shown in Fig. 3, and then the upper surface teeth are formed. Unvulcanized rubber sheets 6, 6 of the necessary predetermined thickness and predetermined length are pasted on the upper surface of the tensile member 2 and the lower surface of the tensile member 2 at opposing positions, and then the unvulcanized rubber sheets 6, 6 of a predetermined width and length are attached thereon. Stretchable canvas 5 with unvulcanized rubber having a constant thickness and having an endless shape or an end shape is wound and laminated.

Next, protrusions h ₁ , h ₂ , h ₁ ′,
₁ consisting of an upper plate R _{1 ,} R ₁ ′ and a lower plate R ₂ , _{R 2 ′} as _shown in FIG. Of the pair of press molds, each of the lower plate R ₂ and the upper plate R ₁ is used for the tooth profile portions 4 and 4 of the vulcanized tooth forming body.
and are clamped by the upper plate R ₁ and the lower plate R ₂ ′, which face each other, and are vulcanized.

As shown in Figures 4 and 5, the mold press has a lower platen.
Knock pins N and N are placed diagonally at both ends of R ₂ and R ₂ ′.
However, on the other hand, pin insertion holes N', N' are formed in the upper plates _R1 , R1 _' at positions opposite to the pins, and the knock pins N,
By inserting and fitting N into the pin insertion holes N' and N', the belt is configured to prevent the upper and lower belt teeth from shifting and form uniformly arranged upper and lower teeth.
In addition, thickness adjustment plates L (2 to 3 mm) are installed on the dowel pins N and N to adjust the belt thickness and form a uniform PLD.
thickness) and multiple thickness fine adjustment plates l (0.5 mm thick) are inserted and fixed.

After fitting the lower plate R ₂ and upper plate R ₁ ′ of the press mold to the tooth portions 4, 4 of the vulcanized tooth forming body as described above, the opposing upper plate R ₁ and lower plate R ₂ ′ of the above configuration are , the dowel pins N, N into which the thickness adjustment L, L have been inserted and the pin insertion holes N', N' are inserted and fitted together to sandwich the unvulcanized rubber sheets 6, 6 and the elastic canvas with rubber 5, 5. Next, the upper and lower heating presses K and K', which are equipped with heating mechanisms (not shown) such as steam and electric heaters inside, and cooling mechanisms C, C, C', and C' on both sides, are indicated by arrows. Vulcanization is performed by applying pressure in the direction. This vulcanization is usually carried out by installing cooling mechanisms C″, C″, C″, C″ on both upper and lower sides between the lower plate R ₂ at the top of the figure and the upper plate R ₁ ′ at the bottom of the figure, as shown in Figure 6. The belt forming width is narrower than that of the upper plate R ₁ , R ₁ ′ and the lower plate R ₂ , R ₂ ′. The rubber flows out to the side of the press die to make the belt thickness uniform. Note that the cooling plate K'' is not always required and may not be inserted.

Therefore, during vulcanization, the unvulcanized rubber sheets 6, 6 exhibit a fluid state, and at the same time, the rubberized elastic canvas 5, 5
While stretching the concave groove g ₁ of the upper plate R ₁ and the lower plate
The concave groove _g2 of _R2 ' is filled to form upper teeth 6', 6'.

Here, the upper plates R ₁ , R ₁ ′ and the lower plates R ₂ , R ₂ ′ of the mold press that form the upper teeth 6, 6 are as described above.
The dowel pins N, N and pin holes N', N' form symmetrical upper and lower teeth that are evenly arranged to fit and fix, and the belt thickness is adjusted by the thickness adjustment plates L, l inserted into the dowel pins N, N. In addition, cooling mechanisms C, C, C', C' provided on both sides of the upper and lower heating presses K and K' as well as mold press R ₂ , R ₁ ' (cooling water is circulated inside as a cooling mechanism), it is possible to prevent the unvulcanized rubber sheets 6, 6 from flowing to the unformed portion.

After molding and vulcanizing the upper teeth 6', 6', the respective press molds R ₁ , R ₂ , R ₁ ', R ₂ ' are removed from the vulcanized tooth forming body, and upper and lower double teeth are partially formed. This results in a belt molded body.

Next, the toothed pulley P ₁ is rotated in the direction of the arrow in Fig. 3 to move the position of the vulcanized tooth forming shape to the left in the figure, and the unformed part is placed on the back of the unformed part of the exposed part of the next tensile member 2 as described above. Vulcanized rubber sheets 6, 6 and elastic canvas with rubber 5, 5 are laminated and pasted in order, and the upper plate R ₁ ,
R ₁ ′ and the lower discs R ₂ , R ₂ ′ are sandwiched and pressurized from above and below by heating presses K and K′ to continuously form upper teeth 6 ′ and 6 ′ on the back surface of the belt to form a wide width. Make an endless vulcanized double timing belt.

Then, the vulcanized double timing belt obtained in the above manner is subsequently cut into a predetermined width in the longitudinal direction to form a tensile body as shown in FIG.
By forming symmetrical tooth portions 4, 6' and tooth troughs with a constant amount of rubber on the upper and lower surfaces of the belt, it is possible to obtain a double timing belt with uniform PLD in the circumferential direction of the belt and on the upper and lower teeth.

As explained above, the method of the present invention involves sequentially pasting an unvulcanized rubber sheet and a rubberized canvas on the back of a single-tooth timing belt that has been molded and vulcanized using a toothed mold, and the laminated portion is equipped with a dowel pin and a thickness adjustment plate. This is a manufacturing method for double timing belts in which partial upper teeth are continuously formed on the back of the belt by fitting and clamping the belt with a pair of grooved press molds and applying pressure and heat from the outside, ensuring that the upper and lower teeth are accurately positioned. It is possible to obtain a double timing belt with uniform PLD in the circumferential direction of the belt and on the upper and lower teeth, and also has extremely good meshing with the toothed pulley when driving the belt, allowing for reliable synchronous transmission. It has features,
It is extremely suitable for use as a multi-axis drive belt, and has the advantage of being much more effective as a belt manufacturing method than conventional methods, such as increasing the transmission force and significantly increasing the belt life.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing an aspect of the molding and vulcanization process of a single tooth-formed body in the double timing belt manufacturing process of the present invention, and FIG. 2 is a partial side view of the single tooth-formed body obtained in the process of FIG. 1. Figure, 3rd
The figure is a side view showing an aspect of the forming and vulcanizing process of the double timing belt of the present invention, Figure 4 is a perspective view of a mold press used in the above process, and Figure 5 is a partially enlarged side view of Figure 4. FIG. 6 is a partial side view showing an aspect of the molding and vulcanization process of the double timing belt of the present invention, and FIG. 7 is a partial side view of the double timing belt obtained by the manufacturing method of the present invention. 1, 5... Elastic canvas with rubber, 2... Tensile rope, 3, 6... Unvulcanized rubber sheet, 3'... Back rubber layer, 4... Lower tooth profile rubber layer, 6... ...Upper tooth, M...Toothed mold, H...Zone-like projection, G...
... Concave groove, P ₁ , P ₂ ... Toothed pulley, R ₁ , R ₁ ′ ... Press mold upper plate, R ₂ , R ₂ ′ ... Press mold lower plate, h ₁ ,
h ₂ , h ₁ ′, h ₂ ′……Mold protrusion, g ₁ , g ₂ , g ₁ ′, g ₂ ′……
Mold groove, N...knot pin, N'...pin insertion hole, L...thickness adjustment plate, l...thickness fine adjustment plate,
C, C', C''...cooling mechanism, K, K'...heating press, K''...cooling plate.

Claims (1)

[Scope of Claims] 1. A method for manufacturing a double timing belt, characterized in that the following steps (a) to (g) are performed in that order. (a) A stretchable canvas with unvulcanized rubber is wrapped around the outer circumferential surface of a cylindrical toothed mold in which belt-like protrusions and grooves are alternately formed in the axial direction of the outer surface, and a low-elongation, high-strength canvas is wrapped around it. A tensile rope is wound in a spiral shape, and an unvulcanized rubber sheet of a certain thickness is further wound around it. A cylindrical sleeve is fitted onto the outer surface of the thus obtained unvulcanized belt, and this is heated and cured. A rubber sheet is extruded and filled into the concave groove portion to form a tooth shape, and a rope layer,
A step of obtaining a vulcanized tooth-forming body in which a tooth-shaped rubber layer and a canvas layer are connected and integrated. (b) removing the vulcanized tooth forming body from the mold;
The step of polishing away the back rubber layer covering the top surface of the tensile body to expose the entire surface of the tensile body, and then winding it around two toothed pulleys whose center distance can be adjusted. (c) 1 consisting of an upper plate with pin insertion holes on both ends and a lower plate with knock pins on both ends, with protrusions and grooves alternately formed at predetermined intervals in the horizontal direction.
A step of fitting the lower plate and the upper plate of each of the pair of press molds into the lower teeth of the vulcanized tooth forming formed around the toothed pulley. (d) Apply an adhesive to the exposed tensile material on the back of the vulcanized tooth forming shape, and apply an unvulcanized rubber sheet of a predetermined thickness and length on top of the adhesive, and an end-shaped or endless sheet of a predetermined length and thickness. Stretchable canvas with unvulcanized rubber of the shape is sequentially laminated and pasted, and the upper plate and lower plate, which are opposite to the upper and lower surfaces of the lower plate that fits with the teeth, and the upper plate, respectively, are inserted into the respective knock pins and pin holes. A step of fitting the upper plate and the lower plate through a plurality of thickness adjusting plates, and sandwiching and pressurizing the unvulcanized laminated portion with a hot press from above and below to form and vulcanize the upper tooth portion. (e) After vulcanization, the step of removing each press mold from the vulcanized tooth forming body. (F) Move the position of the vulcanized tooth forming shape and repeat the steps (C) to (E) in order for the next unformed upper tooth part, and then repeat this further to form a wide endless vulcanized double. The process of obtaining a timing belt. (g) A step of cutting the obtained vulcanized double timing belt into a predetermined width in the longitudinal direction to form a plurality of double timing belts.