JPH0672644B2 - Double timing belt manufacturing method - Google Patents

Description

The present invention relates to a method for manufacturing a double timing belt,
In particular, the present invention relates to a method for manufacturing a double timing belt having upper and lower teeth relatively arranged on the front and back surfaces of the belt and having a structure with a substantially uniform PLD.

(Prior art) The double timing belt is capable of synchronous transmission on the upper and lower sides of the tensile body, and the rotation direction of the driven shaft can be freely changed with one belt. As a result of making a great contribution to the realization, the demand for double timing belts in the market is increasing more and more. However, it is difficult to set the PLD of both upper and lower teeth to be substantially constant and to form the tooth pitch to be constant, and the current situation is that sufficient quality is not satisfied in terms of dimensions and performance. Is.

Conventionally, as a method of manufacturing a double timing belt,
(1) As described in Japanese Patent Publication No. 46-22101, canvas, a tensile rope, an unvulcanized rubber sheet, and a canvas are sequentially laminated and wound on an inner mold with a groove, and a cylindrical rubber mold with a groove on the outer surface. After inserting, the method of forming double upper and lower teeth by pressurizing and vulcanizing the rubber layer into the grooves of the inner mold and the mother mold, and (2) JP-A-49-135056 As shown in the figure above, place the unvulcanized rubber with the premolded rubber cloth on the inner mold with the groove as shown above, wind the tension rope around the spiral, and press the unvulcanized rubber cloth with the same rubber cloth as above. A method in which rubber is laminated, a grooved mold is fitted and then vulcanized, and (3) as described in JP-A-53-71181,
First, a one-sided toothed belt with a thin rubber layer left on the back of the tensile body was semi-vulcanized and formed on its back surface with a protective coating filled with unvulcanized rubber in a predetermined tooth profile. A manufacturing method is shown in which a tooth profile with a molding protection coating is arranged, both of these members are set in a toothed plate press with a belt tensioning device, and heated and pressed.

(Problems to be Solved by the Invention) By the way, among the above-mentioned manufacturing methods, in the manufacturing methods (1) and (2), since the elastic mother die is used to form the upper teeth, the upper and lower teeth are formed. Not only the tooth shape becomes non-uniform due to the position shift and the circumferential length difference, but also the pitch line of the tensile body rope becomes polygonal, the meshing with the timing pulley becomes poor, and the double timing belt has the best quality. There was a problem that the highly accurate PLD required above could not be made uniform. Further, in the production method of (3) above, since press vulcanization is included in one step of the production, it is delicately difficult to control the belt tension at the time of pressing, which leads to a decrease in tension during belt running, As a result, the life of the belt is shortened and a thin rubber layer is left on the back of the belt tensile body. The construction also causes a partial deterioration of the belt.

This invention intentionally reduces the volume of rubber press-fitted into the inner tooth portion of the inner tooth side belt member so that the rubber volume of the inner tooth portion and the tensile body layer falls within a certain range. By limiting, when forming the outer tooth portion of the outer tooth side belt member, a strip-shaped ridge is formed on the back portion of the outer tooth portion and integrally with the outer tooth portion, and the inner tooth side belt member and the outer tooth portion are formed. The side belt member is back-to-back, and the belt-shaped ridge provided on the outer tooth side belt member is sufficient to fill the insufficient rubber volume in the inner tooth side belt member, and at the same time, the inner tooth portion The shape is adjusted and the tooth profile, tooth size (pitch) and PLD uniformity, which are important components of the double timing belt, are realized, and the tension rope is not disturbed and the belt tension is not reduced during running. Proposes an easy-to-manufacture double timing belt manufacturing method An object of the present invention is to.

(Means for Solving the Problems) In order to achieve the above object, the present invention has the following configuration.

That is, the method for producing a double timing belt according to the present invention, a cylindrical internal tooth forming die having a groove group provided on the peripheral surface at a predetermined pitch, a canvas, and a tensile body rope spirally, Furthermore, after winding an unvulcanized rubber sheet with a regulated capacity, insert a cylindrical sleeve to preheat,
The first step of forming the inner tooth side belt member in a plasticized state by pressurizing, the outer tooth forming concave groove on the facing inner wall surface,
A canvas connecting an outer tooth and an outer tooth group in which a canvas and an unvulcanized rubber sheet are interposed between a pair of molds provided with a groove for forming a band-shaped ridge, and external teeth whose outer surfaces are covered with canvas by preheating and pressurization ,
And the second step of forming the outer tooth side belt member in a plasticized state by preheating and pressurizing the strip-shaped ridge portion that is integrally formed with the outer tooth and protrudes from the canvas surface to the side opposite to the outer tooth, The inner and outer teeth of the belt member formed on the back side (opposite teeth side) are positioned so that both the inner and outer teeth face outward, and the belt-shaped ridges of the outer tooth side belt member face the inner tooth side. Then, it is fitted between the outer mold including the cylindrical inner grooved mold and the grooved split mold, and heated and pressed so that at least a part of the strip-shaped ridge is pushed into the inner tooth side belt member. And a fourth step of forming a plurality of double timing belts by cutting the wide double timing belt in a longitudinal direction of a predetermined width, that is, in a ring-like shape. .

(Example) Next, a specific example of a method for manufacturing a double timing belt according to the present invention will be described with reference to the drawings.

FIG. 1 is an end view at the start of the forming operation in the forming step of the internal tooth side belt member with a tensile body rope, and FIG. 2 is an end view at the end of the forming operation. 2 groups of concave grooves extending in the axial direction of the mold are formed on the entire peripheral surface of the mold 1 at a constant pitch, and the peripheral surface of the mold 1 is stretched and woven with nylon, polyester, aromatic polyamide or the like. The elastic canvas 3 is wound by making the expansion and contraction direction of the canvas match the circumferential direction of the mold. On the canvas 3, glass fiber, aromatic polyamide fiber, polyester fiber, which has low elongation and high strength,
Tensile body ropes 4 made of steel wire or the like are spirally wound around the ropes with a predetermined space provided therebetween. Further, the unvulcanized rubber sheets 5 are sequentially wound around the peripheral surface of the tensile body rope 4 in a laminated form, and finally, a cylindrical sleeve (not shown) is covered on the outer side thereof to preliminarily heat and pressurize. Then, a part of the canvas 3 and the unvulcanized rubber, which have been stretched, are press-fitted and filled in the concave groove 2 of the internal tooth molding die 1 to form the internal teeth 7.

At this time, the unvulcanized rubber sheet 5 is pressed from behind and filled in the internal teeth 7 and the voids of the tensile body layer. The volume of the unvulcanized rubber sheet 5 is determined by subtracting the volume of the tensile body rope 4 from the volume of the tensile body layer, that is, by considering the void portion V of the tensile body layer as a reference, The remaining amount of rubber is
The amount of rubber is regulated within the range of -1.0V to 1.0V.
Thus, the internal teeth group whose surface is covered with canvas is connected endlessly with the canvas at the valleys of the internal teeth, and the wide internal teeth in which the spiral tensile rope is arranged on the back of the internal teeth group. The side belt member 6 is formed, and at this time, the rubber material that integrally fills the internal tooth portion and the tensile body layer does not project more than the tensile body layer at the maximum, and the rubber volume is reduced from this amount. The inner tooth side belt member which is in a plasticized state and which is subject to physical regulation is formed.

The unvulcanized rubber sheet 5 extends the canvas 3 and fills the concave grooves 2 of the mold 1, and further partially fills the voids between the ropes of the tensile body layer. In the present invention, the volume of rubber contained in the tensile body layer is set to V mm ^3, and when considering this as a reference, the amount of rubber used when molding the inner tooth side belt member is at the maximum amount, The amount of rubber is set so that it fills the inner tooth portion and the tensile body layer and is quantitatively reduced from that. That is, by setting the range of -1.0V to 1.0V, when the amount of rubber is maximum, the void portion of the tensile body rope 4 that constitutes a part of the internal tooth side belt member 6 is filled, and Is configured so that there is no unvulcanized rubber. Therefore, the unvulcanized rubber sheet 5 has a structure that substantially fills the concave groove 2 of the mold 1 and the rope void portion of the tensile body layer. On the contrary, when the amount of rubber is the minimum, complete internal tooth molding is carried over in the later process due to lack of rubber.

JASO shown in FIG. 3 is the reason why the amount of rubber filled in the tensile body layer of the unvulcanized rubber sheet 5 is set within the above range.
The tooth profile of the toothed belt and the graph shown in FIG.

In FIG. ³ , assuming that the amount of rubber filling the voids in the tensile body layer shown by hatching except the tensile body rope is Vmm ³ ,
V can be expressed by equation (1).

V = 2px (D−a) {1-π (D−a) / 2t} (1) where p = pitch length of toothed belt (mm) D = PLD (pitch line difference) (mm) a = Reinforcement canvas thickness (mm) t = Tensile rope winding pitch (pieces / mm) b = Tensile rope diameter (mm) x = Belt width (mm) The above formula (1) is drawn out. The grounds are as follows.

b = 2 (D−a), Becomes

Due to the above, the void V to be filled with the rubber of the tensile body layer
Is required.

The rubber amount of the unvulcanized rubber sheet 5 is a range in which the PLDs of the inner and outer teeth are substantially matched in relation to the void amount of the tensile body layer, and the inner tooth side belt member 6 is completely filled in the inner tooth portion. , Then the amount of rubber V ¹ filled in the tensile body layer is V ¹ = (-
0.1 to 1.0) V is desirable.

Amount of filled rubber V ¹ and PL in the tensile body layer used when forming the internal teeth 7
The relationship of D is as shown in Fig. 4 with one internal tooth portion, and (a) is the maximum amount of rubber filled with V ¹ = 1.0V, and the rubber surface matches the tensile rope surface. indicates the state, whereas (b) shows a state when the minimum rubber filling of V ¹ = -1.0 V notionally, but insufficient amount of rubber is very small even in the inner toothing unfilled Therefore, there is a portion (in other words, the accurate inner tooth portion 7 is not formed yet).

If V ¹ is −1.0 V or less, the amount of rubber for compensating for the 7 inner teeth becomes too large (the belt-like ridge forming a part of the outer tooth side belt member, which will be described later, becomes too large). When sulfurized
Burrs are likely to occur at the seam of the mold, and as a result, this leads to pitch irregularity of the tensile body.

On the other hand, when V ¹ is 1.0 V or more, the amount of rubber protruding on the tensile body rope becomes too large, resulting in a large loss of conformity between the PLDs of the inner and outer teeth.

The amount of rubber filled when forming the inner tooth side belt member that fills the voids in the tensile body layer is the PLD of both inner and outer teeth of the double timing belt.
It has a large effect on expanding the error of, and the allowable limit of the difference between the PLDs of both teeth is 0.05 mm.

FIG. 5 is a graph showing the relationship between the increase / decrease in the amount of rubber filled in the voids of the tensile body layer used when forming the inner tooth side belt member and the difference in PLD between the inner and outer teeth.

From this graph, the reason for V ¹ = (− 1.0 to 1.0) V can be understood.

Next, the work of molding the outer tooth side belt member will be described.

FIG. 6 is a perspective view showing a state immediately before the forming operation of the outer tooth side belt member, in which a concave groove for forming outer teeth of the belt is formed on the inner surface side (front surface) of the flat plate-shaped lower plate mold 11. 12 groups are the concave grooves 2 of the mold 1 used at the time of molding the inner tooth side belt member 6
The same stretchable canvas 13 as that used at the time of molding the inner teeth is arranged on the lower plate mold 11 in the same shape and pitch as the stretch direction orthogonal to the concave groove 12. It is laid, the unvulcanized rubber sheet 15 is arranged on it, and the upper mold 17 is arranged on it. On the inner surface side (rear surface) of the upper plate mold 17, that is, on the rubber sheet 15 side, shallow grooves 18 are provided at a relative position with the concave grooves 12 of the lower plate mold 11 at the time of stacking, that is, at the same pitch. Has been.

As described above, the pair of upper and lower molds 11 and 17 sandwiches the canvas 13 and the unvulcanized rubber sheet 15 between them, and preliminarily heats and pressurizes the outer teeth 14 group whose surfaces are covered with the canvas 13. , The external teeth 14
An external tooth side belt member 19 in a plasticized state is formed, which is provided with a strip-shaped raised portion 16 protruding above the surface of the canvas 13 that connects the groups (see FIG. 7).

The belt-shaped ridge 16 is provided on the inner tooth side belt member 6
Acting as an elastic member that fills the voids of the internal teeth 7 and the tensile body layer, and the capacity (size) of the strip-shaped ridge 16 is an amount that satisfies the insufficient capacity of the elastic member that constitutes the internal tooth side belt member 6. It is composed of eyes that are roughly equal or have a lot of heart.

The amount of protrusion (height) of the belt-shaped protrusion 16 depends on the amount of filling of the tensile body layer of the unvulcanized rubber sheet 5 of the inner tooth side belt member 6, that is, V ₁ = −1.0. In the case of V, the amount of uplift is large, and the amount of uplift becomes smaller as it moves to the V ₁ = 1.0V side.

Inner and outer teeth 7 of the outer tooth side belt member 19 removed from the pair of molds 11 and 17 on the outer peripheral surface of the inner tooth forming die 1 and the inner tooth side belt member 6 formed thereon. , 14 are wound around the tensile body rope 4 so as to face each other, and the pair of inner and outer tooth side belt members 6, 19 are back-to-back to form an unvulcanized belt molded body,
Further, on the outer side of the outer tooth side belt member 19, a cylindrical split mold 21 having protrusions 23 and concave grooves 22 provided alternately on the inner peripheral surface is arranged, and the respective outer teeth 14 are arranged in the respective concave grooves 22. It is fitted and fitted, and the rubber jacket 24 is fitted on the outer peripheral portion (see FIG. 8). In this state, the belt-like raised portion 16 fixes the inner tooth portion 7 to the mold 1
Is strongly pressed against the concave groove 2 side, the strip-shaped raised portion 16 also fills the insufficient rubber volume portion of the inner tooth side belt member 6, and the inner tooth shape is made more accurate, while the conventional heating, The unvulcanized belt molded body is vulcanized and molded by the pressurizing means to create a wide tubular double timing belt, and in the final process, this wide belt is sliced into a predetermined width to form a desired double timing belt. obtain.

Next, while comparing the tension test of the inner tooth side belt portion and the outer tooth side belt portion of the double timing belt completed by carrying out the present invention with the conventional single tooth timing belt, the running test provided with the following conditions: It experimented using the machine.

The double timing belt used in this experiment is 83WZA1.
Type 9 and 83ZA19 type one-timing timing belt are used, the mounting tension of both belts is 15kgf, and the double timing belt uses the inner tooth rubber volume of -0.3V when manufacturing the inner tooth side belt member. However, the same material was used as the belt material for the one-tooth timing belt. The running tester has the structure shown in FIG. 9 and includes a drive pulley (Dr).
Has 18 teeth, driven pulley (Dn) has 36 teeth, idler pulley (Id) has 18 teeth, and drive pulley rotation speed is 7200rp
m, power is set to 5p / s.

And, in the case of the double timing belt, the experiment was carried out in a forward running state in which the inner tooth portion was hooked on a pair of pulleys (Dr) (Dn), and both the inner and outer tooth portions were turned upside down. The test was carried out while the vehicle was running on the pulley in the reverse direction.

The results of the above running test are verified by the graph showing the relationship between belt tension and running time shown in FIG. When traveling in the reverse direction, that is, when driving the outer tooth side of the double timing belt, a slight decrease in tension can be confirmed in comparison with the inner tooth side driving, but this is almost the same in comparison with the one-tooth timing belt, and is almost the same. As a result, the concern of tension drop in driving both inner and outer teeth was completely eliminated.

(Effect of the Invention) The present invention can ensure the accuracy of the tooth profile of both the inner and outer teeth by forming the inner tooth side belt member and the outer tooth side belt member in advance, and further, the inner and outer tooth side belt members can be secured. Back-to-back, the unvulcanized belt molded body is fitted into a pair of inner and outer grooved molds, and a vulcanization process of heating and pressurizing over two steps is performed, whereby the tooth size, that is, the tooth pitch is disturbed ( (Error) is reliably suppressed. In addition, the inner tooth shape is made more accurate by applying a pressing force to the inner tooth molding die part with a strip-shaped ridge part integrally attached to the outer tooth side belt member from the back part. In addition, a part of this strip-shaped ridge is press-fitted into the inner tooth side belt member, the joint body of both inner and outer tooth side members becomes even stronger, and the PLD of both inner and outer teeth is uniform. The tension is maintained, and the tension rope is not disturbed, so that it is possible to prevent a decrease in belt tension when the belt is running.

[Brief description of drawings]

FIG. 1 is an end view of the internal tooth side belt member with a tensile body rope at the start of the forming operation, and FIG. 2 is an end view at the end of the forming operation.
FIG. 3 is an end view of one tooth portion of the inner tooth side belt member, and FIG. 4 is a sectional view of one inner tooth portion at the time of molding the inner tooth side belt member,
(A) is a schematic explanatory view at the time of maximum rubber filling, (B) is a schematic conceptual explanatory view at the time of minimum rubber filling, and FIG. 5 is a view of the rubber filled in the void portion of the tensile body layer at the time of internal tooth molding. Increase / decrease amount and both internal and external teeth
A graph showing the relationship of the difference in PLD, FIG. 6 is a perspective view of a part of the external tooth side belt portion at the start of forming work, FIG. 7 is a perspective view of a part of the external tooth side belt member, and FIG. End view of a part of the components at the start of the forming work of the wide double timing belt,
FIG. 10 is a schematic explanatory view of a belt running tester for carrying out a belt tension test according to the present invention, and FIG. 10 is a graph showing running test results of the belt according to the present invention and a conventional one-tooth timing belt. 1 …… Internal tooth forming mold 2,12,22 …… Concave groove 3,13 …… Canvas 4 …… Tensile rope 5,15 …… Unvulcanized rubber sheet 6 …… Internal tooth side belt member 7 …… Internal teeth 11 …… Lower plate mold 14 …… External teeth 16 …… Band-shaped ridges 17 …… Upper plate mold 18 …… Shallow groove 19 …… External tooth side belt member 21 …… Split mold 24… … Rubber jacket

Claims (6)

[Claims] (1) When a cloth, a tensile rope is spirally wound around a mold provided with a group of grooves, and an unvulcanized rubber sheet is successively wound, the rubber sheet is covered with the cloth. The maximum width that can fill the inner tooth part and the tensile body layer is reduced, and the capacity is reduced from that. Step of forming a member, (b) A canvas and an unvulcanized rubber sheet are placed between a pair of molds each having a groove group at a relative position, and covered with a canvas by preheating and pressing. A step of forming a wide outer tooth side belt member having a belt-like ridge integrally formed with the outer tooth, which protrudes from the canvas surface connecting the outer tooth and the outer tooth group, and (c) the outer circumference of the inner tooth side belt member. The outer tooth side belt member is wound with both the inner and outer teeth facing outward, and the inner and outer surfaces have concave grooves. Molding process, vulcanization molding of wide endless double timing belt while pressing inner teeth against the mold at the belt-shaped ridge of the outer tooth side belt member, (d) Wide double timing A step of forming a plurality of double timing belts by cutting the belt into a predetermined width, and a method of manufacturing a double timing belt, which comprises performing the steps (a) to (d) above. 2. In the step of forming an inner tooth side belt member, the unvulcanized rubber sheet which fills the inner tooth portion and the tensile body layer has a rubber amount V of the tensile body layer after the inner tooth portion is formed. The method for producing a double timing belt according to claim 1, wherein the rubber amount is set in the range of -1.0V to 1.0V. 3. The amount of protrusion of an unvulcanized rubber sheet constituting the inner tooth side belt member is reduced by the amount, and the amount of protrusion of the strip-shaped raised portion constituting the outer tooth side belt member is increased. 2. The method for manufacturing a double timing belt according to 2. 4. A method for manufacturing a double timing belt, which comprises performing the following steps: (a) An inner tooth group whose surface is covered with canvas is endlessly held with the canvas at the valley of the inner teeth. When forming a wide belt on the internal tooth side with a spiral tensile rope arranged on the back of the internal tooth group, the rubber material that fills the internal tooth and tensile layer together is the maximum tensile force. The process of forming the inner tooth side belt member that is in a plasticized state and is regulated by the volume that does not protrude beyond the body layer, and (b) the outer tooth whose surface is covered with canvas. The group is connected with the above-mentioned canvas at the valley of the external teeth, and the strip-shaped ridge protruding from the canvas surface is integrally formed on the back of the external tooth, and both the external tooth and the strip-shaped ridge are plasticized. Step of forming a certain wide outer tooth side belt member, (c) concave The outer tooth side belt member is wound around the outer peripheral surface of the inner tooth side belt member mounted on the metal mold with both the inner and outer teeth being positionally facing outward, and a cylindrical recess is formed on the outer side. A step of arranging a grooved mold and vulcanizing a wide endless double timing belt by pressing the inner tooth part against the mold with a strip-shaped ridge, (d) Slicing a wide double timing belt into a predetermined width Then, the step of forming a plurality of double timing belts. 5. In the step of forming the inner tooth side belt member, the unvulcanized rubber material that fills the inner tooth portion and the tensile body layer has a rubber content of V after the inner tooth portion is formed is V. And when
The method for manufacturing a double timing belt according to claim 4, wherein the amount of rubber is set in the range of -1.0V to 1.0V. 6. The amount of protrusion of the belt-shaped protrusion forming the outer tooth side belt member is increased by the amount corresponding to the volume of the unvulcanized rubber material forming the inner tooth side belt member being reduced quantitatively. A method for manufacturing the double timing belt described.