JPH02167730A - Toothed endless belt - Google Patents

Abstract

PURPOSE:To reduce noise without damaging molding properties and to enhance durability still more by impregnating reinforcing cloth with a soft elastomer and covering the threads of the impregnated reinforcing cloth with hard elastomer. CONSTITUTION:An endless belt has a belt main body 1 composed of a casting elastomer and having a tensile body 6 embedded therein and the tooth part 3 integrally formed to the belt main body 1 from the casting elastomer. Reinforcing cloth 4 is mounted to the surface of said tooth part 3 through a buffer layer 7 composed of an impermeable elastomer and impregnated with an elastomer in order to enhance durability. This reinforcing cloth 4 is impregnated with the soft elastomer and the threads of the impregnated reinforcing cloth are pref. coated with a hard elastomer. The surface layer of the reinforcing cloth may be impregnated with the hard elastomer and the rear layer thereof on the side of the buffer layer 7 may be impregnated with the soft elastomer. Since yarn like fibers are not exposed to a surface as they are as mentioned above, the reinforcing cloth is hard to be damaged and, as a result, the durability and the life of the belt are enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a toothed endless belt molded from a casting elastomer having reinforcing cloth attached to the surface of the teeth.

(Prior art) Conventionally, toothed endless belts made of castable elastomers such as castable polyurethane with a tensile material as a core have been used as power transmission systems that avoid contamination by rubber debris etc. due to the characteristics of the material. It is used as a tie belt in transportation systems.

In recent years, in order to reduce noise and improve durability, reinforcing cloth has been placed on the surface of the teeth formed by cast elastomer, and belt forming has been carried out by pressurized injection of cast elastomer, especially at the same time the reinforcing cloth has been stretched. Toothed endless belts are known in which a buffer layer is formed between the reinforcing cloth and the teeth using an impermeable elastomer to form a tooth-shaped bottom. This belt was proposed by the present applicant in Japanese Unexamined Patent Publication No. 63-214538.

(Problem B to be solved by the invention) Although the toothed belt provided with the reinforcing cloth and the buffer layer facilitates the bottom shape and reduces noise,
The reality is that the reinforcing fabric is severely damaged and does not have sufficient durability.

The present invention was made in view of the above problems, and an object of the present invention is to dramatically improve the durability of a toothed endless belt whose bottom is made of castable elastomer and is provided with a reinforcing cloth.

(Means for Solving the Problems) The toothed endless belt of the present invention, which has been made to achieve the above object, is made from a castable elastomer and has a belt body l having a tensile member 6 embedded therein. This belt body 1 has a toothed portion 3 integrally formed of the casting elastomer, and a reinforcing cloth 4 is attached to the surface of the toothed portion 3 via a buffer layer 7 made of an impermeable elastomer. In the toothed endless belt, the reinforcing cloth 4 is impregnated with an elastomer to improve durability.

In this case, the reinforcing cloth is preferably impregnated with a soft elastomer, and the woven threads of the impregnated reinforcing cloth are coated with a hard elastomer. Alternatively, the surface layer of the reinforcing cloth may be impregnated with a hard elastomer, and the back layer on the side of the buffer layer may be impregnated with a soft elastomer.

In this case, as the elastomer impregnated into the surface layer of the reinforcing cloth, an elastomer containing a substance that lowers the coefficient of friction or an elastomer modified with the substance may be used.

(Function) The reinforcing fabric of the toothed endless belt of the present invention is impregnated with a durable elastomer, and unlike conventional reinforcing fabrics, thread-like fibers are not exposed on the surface as they are.
The reinforcing fabric according to the present invention is difficult to damage, and as a result, the durability and life of the belt are improved.

As for the elastomer to be impregnated into the reinforcing fabric, it is better to use a hard one with a large modulus from the standpoint of reducing noise due to a reduction in the coefficient of friction and improving durability.However, if only a hard elastomer is impregnated, the tooth formation shape will occur due to the elongation of the reinforcing fabric. It becomes difficult. On the other hand, as shown in FIG. 6, when a reinforcing cloth is impregnated with a soft elastomer A having a small modulus, and a hard elastomer B is further coated on the woven yarn 4a of the impregnated reinforcing cloth, the moldability and physical properties are improved. can be improved together.

Furthermore, even if the surface layer of the reinforcing cloth is impregnated with hard elastomer B and the back layer on the side of the buffer layer 7 is impregnated with soft elastomer A, both moldability and physical properties can be improved. It is suitable because it can be done.

At this time, the friction coefficient of the elastomer in the surface layer is lowered,
To reduce noise, use an elastomer impregnated into the surface layer that contains a substance that lowers the coefficient of friction, such as a fluororesin or silicone resin, or one that has been modified with such a substance (for example, silicone-modified polyurethane). do it. Such elastomers usually have poor adhesive properties, but in the present invention, they are used by impregnating them into reinforcing fabrics, so they are physically firmly fixed to the reinforcing fabrics by embedding the fibers. Furthermore, since the back layer of the reinforcing fabric is impregnated with a natural elastomer that does not contain the above-mentioned substances and is not modified by the substances, the adhesion between the impregnated reinforcing fabric 4 and the buffer layer 7 is also good. It is.

(Example) Hereinafter, the toothed endless belt according to the present invention will be described together with its manufacturing method.

FIG. 1 shows that toothed portions 3 are integrally formed on the inner circumferential surface of a belt main body l via land portions 2 at equal intervals in the circumferential direction, and the surfaces of the toothed portions 3 and land portions 2 are coated with a predetermined elastomer. 1 shows an endless belt 5 provided with an impregnated reinforcing fabric 4; The belt body 1 and the teeth 3 are made of castable elastomer material such as castable polyurethane, and a tensile body 6 is embedded in the belt body 1 in a helical manner. As shown in FIG. 2, a buffer layer 7 made of an impermeable elastomer material such as thermoplastic polyurethane is provided between the teeth 3 and the reinforcing cloth 4 with a substantially uniform thickness over the entire surface.

FIG. 3 shows a mold apparatus used for manufacturing the endless belt 5. As shown in FIG. That is, in FIG. 3, 8 is an inner mold, 9 is an outer mold,
These inner and outer molds 8.9 are provided concentrically to form a predetermined space 10, and are separable. Inner and outer mold 8.9
An upper lid 11 and a lower 1fl12 are removably provided at both upper and lower ends of the mold, and the space 10 between the inner and outer molds 8 and 9 is sealed by the upper and lower lids 11.12. Further, a deaeration hole 13 is formed in the upper lid 11 so as to communicate with the space IO, and an opening/closing screw 14 is screwed into the deaeration hole 13 in a detachable manner. 15 is liquid casting elastomer material 1
The outer mold 9 is poured into the outer mold 9 through the injection pipe 17 using a casting container containing 6
The elastomer material 16 can be poured from the tube 17 into the space 10 of the inner and outer molds 8, 9 by pressurizing the piston 18. As shown in FIGS. 4 and 5, an uneven portion 19 for forming the tooth portion 3 of the endless belt 5 is provided on the outer circumference of the inner mold 8 over the entire circumference.

To manufacture the endless belt 5, first, a reinforcing cloth is impregnated with an elastomer to improve durability.

As the reinforcing cloth, highly elastic woven or knitted fabrics made of synthetic fiber threads such as nylon or polyester, rubber threads, etc., and nonwoven fabrics made of the same fibers can be used. Weaving yarn (including knitting yarn).

) can be made of single yarn, double yarn, twine, or crimped yarn. The fabrics used include plain weave, twill weave, and satin weave.

The elastomer to be impregnated into the reinforcing cloth is preferably one with a low coefficient of friction and good abrasion resistance.

In other words, a material with a large modulus and hardness is preferable.

However, it is necessary to consider the formability of the reinforcing cloth 4 after impregnation, and when impregnating one type of elastomer, it is necessary to use polyurethane or the like with a 100% modulus of 10 to 350 kgf/crA (preferably 30 to 25 Qkgf/crA). An elastomer is used.The impregnation method is usually to dissolve the resin in a solvent and adjust the viscosity (preferably 500%
00 cps or less).

In this case, as a first treatment, the reinforcing fabric is immersed in a treatment liquid containing a soft elastomer and dried, and then as a second treatment, it is immersed in a treatment liquid containing a hard elastomer, and as shown in Figure 6, the reinforcing fabric is By coating the surface of the woven yarn 4a impregnated with the elastomer A with the hard elastomer B, a reinforcing cloth 4 having a low coefficient of friction, good wear resistance, and good moldability can be obtained. The soft elastomer has a 00% modulus of 10 to 250 kgf/
polyurethane, hard elastomer and LT cd (preferably lO~150 kgf/aj) 20~350
kgf/cnl (u ma L < ha lOO ~ 350
kgf/c4), and when using the exemplified polyurethane, the viscosity of the primary treatment liquid is 10,000 cps or less, and the viscosity of the secondary treatment liquid is 2.
It is preferable to adjust it to 0,000 cps or less.

In addition, in order to have both excellent physical properties and moldability, a coating liquid containing a hard elastomer dissolved in the surface layer of the reinforcing fabric was applied and dried, and then a soft elastomer was dissolved in the back layer on the buffer layer side. A coating liquid may be applied. Through this coating process, as shown in FIG. 7, a reinforcing cloth 4 is obtained in which the surface layer is impregnated with the hard elastomer B and the back layer is impregnated with the soft elastomer A. The viscosity of the coating liquid used in coating treatment may be higher than that in dipping treatment, and the coating liquid for impregnating a soft elastomer is prepared to have a viscosity of 20,000 cps or less, and the coating liquid for impregnating a hard elastomer is prepared to have a viscosity of about 50,000 cps or less.

At this time, in order to further reduce noise by lowering the coefficient of friction of the surface layer, the hard elastomer B may be one containing a substance that lowers the coefficient of friction (for example, polyurethane containing fluororesin or silicone resin). A material modified with the same substance (for example, silicone-modified polyurethane) may be used. In this case, if a large amount of fluororesin or the like is contained, the abrasion resistance will be reduced, so it is preferable to limit the content to 50% by weight or less.

The reinforcing cloth 4 that has been subjected to a predetermined impregnation treatment is then subjected to a sealing treatment (filling the spaces in the weave with a predetermined elastomer to close the spaces) and forming a buffer layer 7 of a predetermined thickness. The material for the filling material and the buffer layer 7 should have a hardness of durometer A20-D80 (preferably J■) when made into a product.
An elastomer such as polyurethane having a durometer of 5-A4o to D60) is used. The elastomer may be either thermoplastic or thermosetting, and is prepared to have a viscosity of 50,000 cps or less and is applied several times (when drying, the applied flO
~2000 gf/bo), sealing treatment etc. are performed.

Note that the thickness of the buffer layer 7 is approximately 0.01 to 2.00 mm.

The sealing treatment and the formation of the buffer layer 7 may be carried out by applying a treatment liquid containing an elastomer, or by thermocompression bonding a sheet material formed of the elastomer to the reinforcing cloth 4. In this case, thermocompression bonding is performed at a temperature below the softening point of the sheet material,
You can completely seal the eyes with a simple operation. Moreover, since the reinforcing cloth 4 has been subjected to a predetermined impregnation treatment, its adhesion to the sheet material is also good.

The sheet material to be thermocompressed is made of two layers of elastomers with different softening temperatures, and the layer on the low softening point side is brought into contact with the reinforcing cloth 4. It is best to bond by thermocompression at high temperature. This is because the elastomer with a low softening point is embedded in the weave, contributing to improved durability. In this case, the difference in softening temperature is preferably 5 layers C or more from the viewpoint of workability.

Next, this reinforcing cloth 4 is cut, and after being processed into an endless cylindrical shape by sewing with a thread, adhering or fusing with a heat press, etc., it is attached to the inner mold 8 of the mold device in an outer-fitting manner, A tensile member 6 is spirally wound around the inner mold 8 from the outside of the reinforcing cloth 4. As the tensile member 6, a synthetic fiber rope such as aromatic boria, nylon, or polyester, steel wire, or the like is used.

Once the reinforcing cloth 4 and the tensile material 6 have been attached to the inner mold 8, the inner mold 8 is inserted into the outer mold 9 and the inner and outer molds 8,
9 are combined to form a predetermined space 10. At this time, both ends of the reinforcing cloth 4 in the width direction are bent from both upper and lower ends of the inner mold 8 toward the center, and the inner mold 8 and the upper and lower ends 1i11.
Both ends of the reinforcing cloth 4 are sandwiched and fixed between the reinforcing cloth 4 and the reinforcing cloth 12.

After heating the entire inner and outer molds 8.9 to the curing temperature of the elastomer, the liquid elastomer material 16 in the casting container 15 is pressurized with a pressure P (2 kgf/d or less) with the piston 18, and the injection tube is 17 to fill the space 10 between the inner and outer molds 8.9. The liquid elastomer material 16 has a hardness of Durome A20 to D8 when made into a product.
0 (preferably JIS A70~100''), for example, a mixture of a polyurethane polymer and a curing agent is used.The viscosity is 2000~400''.
It is adjusted to about 0 cps.

When the space 10 is filled with the elastomer material 16, it flows out from the deaeration hole 13 of the upper lid 11, and at the time it flows out, the opening/closing screw 14 is screwed into the deaeration hole 13 to seal the deaeration hole 13. And after this sealing, 10-30k
Pressure is applied to the reinforcing fabric 4 through the elastomer material 16 by pressure molding of gf/afl. Since the reinforcing cloth 4 is sealed by the buffer layer 7 and the elastomer material 16 does not penetrate, it is deformed along the shape of the uneven portion 19 on the outer periphery of the inner mold 8 while being stretched together with the buffer layer 7 due to pressure, and the inner mold 8 is Reliably adheres to the outer peripheral surface of the mold 8 without any gaps. Even during this pressurization, since both ends of the reinforcing cloth 4 are fixed between the inner mold 8 and the upper and lower parts 1i11.12, the reinforcing cloth 4 does not move or shift due to the pressurization.

In addition, the reinforcing cloth 4 and the buffer layer 7 have an elongation rate (length of elongation 7 original) of 1.4 (preferably 0.01) during pressure forming of the belt.
8) It is best to stop at the following. This is because if the amount of deformation becomes too large, the reinforcing cloth etc. will be easily damaged and there is a risk that the seal will come off.

Once the elastomer material 16 is cured, the upper and lower lids 11.12
After removing and separating the inner and outer molds 8.9, the molded product is demolded,
By slicing the molded product into a predetermined product width,
An endless belt 5 can be manufactured.

The structure and shape of the endless belt are not limited to those shown in Figure 1,
If the belt body 1 has reinforcing cloth 4 on the side surface,
It can be widely adopted for its production. For example, FIG. 8 shows a symmetrical type in which teeth 3 and 25 are symmetrically provided on the inner and outer peripheral surfaces of the belt body 1,
FIG. 9 shows an asymmetrical endless belt 26 in which the inner and outer teeth 3.25 are offset in the circumferential direction. In addition, FIG. 10 shows a toothed portion 3 on the inner circumferential surface of the belt body 1 and a 7-shaped protrusion 29 on the outer circumferential surface.
An endless belt 30 is shown in which these are integrally formed. In these cases, the surfaces of the tooth portions 3.25 and the protruding portions 29 are covered with reinforcing cloth 4,
I'm trying to cover it with 27.31.

It is also possible to provide a thin layer of silicone, fluorine or other synthetic resin or elastomer on the surface of the reinforcing cloth 4.27.31. In this way, the friction coefficient of the surface of the reinforcing cloth 4, 27, 31 can be changed arbitrarily, and the field of use of the belt will be expanded.

Next, specific examples will be listed and explained.

(1) A woven fabric of nylon fibers was used as a reinforcing fabric and subjected to the following impregnation treatment. The thickness of the reinforcing fabric after dipping was approximately 0.6 mm in each example.

・Example 1 100% modulus 150 kgf/c by immersion treatment
Impregnated with IIN polyurethane. The viscosity of the immersion treatment liquid was 3000 cps.

・Example 2 As shown in Figure 6, primary immersion treatment (processing liquid viscosity 2000
cps) to woven fabric by 100 kgf/c+i
1 of polyurethane, and after drying, a secondary dipping treatment (treatment liquid viscosity 5000 cps) gives the primary impregnated yarn a 100% modulus of 200 kgf/a+1.
coated with polyurethane.

・Example 3 As shown in Figure 7, the back layer of the reinforcing cloth was coated (coating liquid viscosity 5000 cps) to give a 100% modulus of 10.
Impregnated with 0 kgf/c1a polyurethane, on the other hand,
The surface layer was impregnated with fluororesin-containing polyurethane (30% by weight) having a 100% modulus of 200 kgf/cffl by the same treatment (coating liquid viscosity: 10,000 cps).

(2) A polyurethane sheet with a thickness of 0.4 mm (hardness JISA 8
5. A buffer layer was formed by thermocompression bonding at 120°C (softening temperature: 150'C). At this time, as a conventional example, a buffer layer was formed in the same manner on a reinforcing cloth similar to that of the example but not subjected to the impregnation treatment.

(3) After endlessly processing the reinforcing fabrics having the buffer layer of Examples 1 to 3 and the conventional example into a cylindrical shape, as shown in Figs. A polyamide fiber rope was wound spirally and then inserted into an outer mold to form a molding mold.

After heating the mold to about 110'C, the hardness after hardening is J
A liquid polyurethane for casting (including a hardening agent, viscosity 2,000 to 4,000 cps) having an ISA of 85 was poured into a mold, and after sealing, pressure molding was performed under molding conditions of 110°C, 12C12O/c, and the mold was held in this state for 60 minutes.

After the molding was completed, the molded product was demolded and cut into a predetermined width to obtain a toothed endless belt.

(4) Using the belts of Examples 1 to 3 and the conventional example, belt performance was examined in the following manner.

■ Measurement of friction coefficient μ A sample piece of a certain length was taken from the belt, and a steel plate (material 5S
41, surface roughness R,,,25S), the belt piece is placed so that the tooth surface is in contact with it, a constant load W is applied to the belt piece, it is pulled, and the force F required to move it at a speed of 1c+n/sec.
was calculated, and μ-F/W was calculated.

■ Abrasion resistance evaluation A standard mounting tension was applied to a pair of drive-side pulleys and a load-side pulley, the belt was passed over a rack, and a constant load (brake) was applied to the drive pulley at 300 rpm (belt circumferential speed 2.6).
The weight of the belt was measured after a certain period of time (m/sec), and the difference (weight loss) from the original weight was determined and used as an evaluation standard. The belt testing machine was also used for the following tests.

■Measurement of Jumping Torque The belt was run with the belt tension set to the standard installation tension of 172, and the transmitted torque (jumping torque) immediately before jumping was measured while changing the load.

■ Measurement of maximum transmittable torque The belt was run with standard mounting tension applied, and the maximum transmittable torque was measured by varying the load.

■Durability evaluation After applying standard mounting tension and running the belt for a certain period of time under a load close to jumping torque, the state of damage (missing) caused by wear on the belt teeth was examined, and this was used as the evaluation standard.

(2) Measurement of Noise The belt was run under a constant load with a standard installation tension applied, and a sound level meter was installed at a position opposite to the belt running surface and 3 ocma above the running surface to measure the noise during running.

(5) The measurement results are shown in Table 1. The numbers in the table are expressed as an index, using the belt of Example 1 as a reference (index 100).

Table 1 According to Table 1, in Examples 1 to 3, the friction coefficient increased to about twice that of the conventional example, and as a result, the noise increased about twice, but the wear resistance and durability A dramatic improvement of more than 10 times was achieved. Also, in the examples,
Example 2, in which two layers of reinforcing fabric yarn were covered and hard polyurethane was arranged on the surface layer side, and Example 3, in which the surface layer side was impregnated with hard polyurethane containing fluororesin, were more durable than Example 1. improvement and noise suppression.

(Effects of the Invention) As explained above, the toothed endless belt of the present invention has reinforcing fabric impregnated with an elastomer to improve durability, so although the noise increases slightly, it is more durable than conventional belts. This was a dramatic improvement of more than 10 times.

In addition, by impregnating the reinforcing cloth with a soft elastomer and coating the woven yarn of the impregnated reinforcing cloth with a hard elastomer, or by impregnating the surface layer of the reinforcing cloth with a hard elastomer and coating the back layer with a soft elastomer. By impregnating it with an elastomer, it is possible to reduce noise and further improve durability without impairing moldability.

Further, as the elastomer impregnated into the surface layer of the reinforcing cloth, an elastomer containing a substance that lowers the coefficient of friction or modified with the substance is used, and as a soft elastomer impregnated into the back layer, an elastomer that does not contain the above-mentioned substance and is By using a material that does not change depending on the substance, 1. Noise can be further reduced.

[Brief explanation of the drawing]

Fig. 1 is a perspective view of a belt showing an embodiment of the present invention, Fig. 2 is a cross-sectional view of the belt, Fig. 3 is a cross-sectional view of the mold device, and Fig. 4 is a cross-sectional view of essential parts of the mold. , Fig. 5 is a plan view of the same cross-section, Fig. 6 is an enlarged cross-sectional view of the woven yarn of the reinforcing fabric impregnated by the primary and secondary dipping treatments, and Fig. 7 is a plan view of the same cross-section. A partial cross-sectional view of the treated reinforcing fabric,
8 to 10 are perspective views of belts showing other embodiments. 1...Belt body, 2...Land part, 3.25...
・Tooth part, 4.27.31...Reinforcement cloth, 5,26.30
... Endless belt, 6 ... Tensile body, 7 ... Buffer layer,
8...Inner mold, 9...Outer mold, 10...Space, 1
DESCRIPTION OF SYMBOLS 1... Upper lid, 12... Lower lid, 16... Liquid casting material, 19... Uneven part.

Claims (4)

[Claims] (1) Made of castable elastomer and has a tensile material inside (
6) is embedded in the belt body (1), and a tooth portion (3) integrally formed with the belt body (1) from the casting elastomer, and the surface of the tooth portion (3) has a A reinforcing cloth (4) is inserted through a buffer layer (7) made of an impermeable elastomer.
), wherein the reinforcing cloth (4) is impregnated with an elastomer to improve durability. (2) The toothed endless belt according to claim 1, wherein the reinforcing cloth (4) is impregnated with a soft elastomer, and the woven threads of the impregnated reinforcing cloth are covered with a hard elastomer. (3) The toothed endless belt according to claim 1, wherein the reinforcing cloth (4) has a surface layer impregnated with a hard elastomer and a back layer on the side of the buffer layer (7) impregnated with a soft elastomer. (4) The surface layer of the reinforcing fabric (4) contains a substance that lowers the coefficient of friction or is impregnated with an elastomer modified with the substance, and the back layer on the side of the buffer layer (7) contains the substance. The toothed endless belt according to claim 1, wherein the toothed endless belt is impregnated with an elastomer that is not modified by the substance.