JP2965403B2 - High load transmission toothed belt - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improved toothed belt for high load transmission in which an aramid fiber core is embedded as a tensile member in a polyurethane resin belt body.

[0002]

2. Description of the Related Art Conventionally, toothed belts for high-load transmission have been used for driving large-sized processing machines such as machine tools and molding machines. Conventionally, a toothed belt having a structure in which a glass fiber core body as a tensile member is buried in rubber and the tooth surface is reinforced with a nylon woven fabric has been used. However, in recent years, there has been an increasing demand for toothed belts that can be used under even higher load conditions. In response to this, a polyurethane resin having a strength higher than that of rubber is used, and a core of aramid fiber is contained in the polyurethane resin belt body. Attempts have been made to cope with high-load conditions by embedding the steel and further reinforcing the teeth with a woven or nonwoven fabric.

[0003] There are roughly two types of failure modes of a toothed belt that reach the end of its service life: tooth shearing and belt cutting. To improve the former tooth shear life, it is important to increase the belt tensile elasticity so that the pitch of the belt teeth can be maintained accurately even when a load is applied, and to increase the fatigue strength of the tooth receiving the load. It is necessary to. Further, in order to improve the latter belt cutting life, it is necessary to reduce the body fatigue when the belt is repeatedly wound around a small-diameter pulley.

[0004]

With respect to the above-mentioned polyurethane resin toothed belt, the core constituting the tensile member is changed from glass fiber to aramid fiber having a high elastic modulus, and the rubber of the belt body is made of polyurethane resin. As a result, the belt tensile modulus and the tooth fatigue strength are greatly improved as compared with the conventional art, and as a result, the tooth shear life can be significantly improved.

[0005] On the other hand, however, there is a problem that the bending fatigue of the heart is slightly worse than that of the related art because the heart has a high elastic modulus. Therefore, the range of use of the toothed belt made of a high-load polyurethane resin is limited at present, as it cannot be used with small pulleys and cannot be used at high speed because the number of repeated bending is large. . In particular, the restriction that small pulleys cannot be used is a major drawback in large processing machines.Because the pulleys have to be large, there is a problem that the belt transmission system takes up a large space and the device itself becomes large. .

The present invention has been made to solve these problems, and an object of the present invention is to improve the configuration of the above-mentioned aramid fiber core, thereby improving the tooth shear life of a toothed belt made of polyurethane resin. Another object of the present invention is to improve the belt cutting life so that the belt can be used even with a small pulley or high rotation.

[0007]

In order to achieve the above-mentioned object, it has been found in the invention of claim 1 that by increasing the belt Young's modulus, the shear life of the teeth is extended, In order to achieve both increase and flex fatigue, filament denier, total denier, number of core twists, core twist factor, and twist of the aramid fiber core buried as a tensile member in a polyurethane resin toothed belt coefficient,
The body occupancy ratio with respect to the belt width is specified.

That is, according to the present invention, an aramid fiber core as a tensile member is buried in a belt body made of a polyurethane resin having teeth at regular pitches on the inner surface thereof along the bottom of the teeth, and woven in the teeth. In the high load transmission toothed belt on which a reinforcing material layer such as a cloth, a knitted cloth, or a nonwoven fabric is formed, the above-mentioned aramid fiber core has a filament denier 0.9 d
The filament is e~1.6de, 16.3P the belt tooth pitch P (unit mm) ² <d <24.5P ²
The filament bundle obtained by bundling hundreds to thousands of bundles so as to have a denier number d is twisted with a twisting coefficient of 1.2 to 4.2, and five twisted yarns are arranged in the opposite direction to the twisting direction. by twisting up in 3.2 to 4.2 above twist factor in the direction, tension member the total denier number D is 82P ² <D <and 122P ^2, and teeth with 75% to 95% Traction occupancy the belt width It is buried along the bottom.

According to the second aspect of the present invention, the belt tooth height h
(Unit mm) to 1.00 for pulley groove depth H (unit mm)
H <h <1.02H.

According to the third aspect of the present invention, the aramid fiber core is made of aramid fiber whose crystal orientation angle is set to about 9 ° by heat drawing.

[0011]

According to the first aspect of the present invention, the aramid fiber core as the belt tensile member has a filament denier of 0.9 denier.
Hundred to 1.6 thousand filaments are bundled, and several hundred to several thousand filaments are bundled and ply-twisted, and the ply-twisted yarn is ply-twisted in the direction opposite to the ply-twisting direction, and the ply-twisting coefficient of the plied yarn is 3.2 to 3.2.
Since it is 4.2, both the Young's modulus of the belt and the flex fatigue can be compatible.

At this time, the ply twist coefficient of the ply twist yarn is 1.2.
Since it is 4.2, the meandering of the belt due to the deterioration of the balance of the twist of the core body itself does not occur, and the reduction of the belt Young's modulus due to an increase in the twist coefficient can be prevented.

[0013] Further, since five lower twisted yarns are aligned and upper twisted, the bending fatigue resistance can be improved while ensuring the belt Young's modulus. Further, regarding the pitch P of the belt tooth portion, the number d of the lower twist yarn in the aramid fiber core body is 16.3P ² <d <24.5P ² ,
Since the total denier number D of the body is 82P ² <D <122P ² , the belt Young's modulus and the flex fatigue can be compatible with these limits.

The occupation ratio of the core to the belt width is 75%.
Since it is ９５95%, a sufficient elastic modulus can be obtained, delamination between the tooth portion and the tensile member layer is hardly caused, and the tooth portion shear life can be prolonged.

As described above, the increase in the belt Young's modulus allows both the improvement of the shear life of the teeth and the improvement of the bending fatigue, and the improvement of the shear life of the teeth in the polyurethane resin high load transmission toothed belt. In addition, it is possible to improve the belt cutting life and to use the pulley at a high speed or a small pulley.

According to the second aspect of the present invention, the belt tooth height h
Is 1.00H <h <1.02H with respect to the pulley groove depth H, the belt tooth bottom contacts the pulley tooth top in a state where the initial tension is applied to the belt, and a proper meshing state can be obtained. It is possible to improve flex fatigue.

According to the third aspect of the present invention, since the orientation angle of the crystal of the aramid fiber in the core body is set to about 9 °, each of the above effects can be obtained effectively.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a toothed belt B for high-load transmission according to one embodiment of the present invention. This belt B has basically the same configuration as a conventional toothed belt, and has an inner surface with a pitch P of pitch. A belt body 1 having tooth portions 2, 2,... Is provided, and a core body 3 made of aramid fiber as a tensile member is embedded along the bottom of each tooth portion 2 of the belt body 1. Belt body 1
Is made of a polyurethane resin having a JIS / A hardness of 85 ° to 93 °. Further, a reinforcing material layer 4 made of a woven fabric, a knitted fabric, a nonwoven fabric, or the like is formed on each tooth portion 2.

The feature of the present invention lies in the structure of the aramid fiber core 3 constituting the above-mentioned tensile member.
That is, the total denier number D of the aramid fiber core 3
(Denier) is in the range of 82P ² <D <122P ² with respect to the tooth pitch P (unit: mm) of the belt B. The filament bundle denier number d (unit denier) is also in the range of 16.4P ² <d <24.4P ² . The filament bundle is pre-twisted at a pre-twisting coefficient of 1.2 to 4.2 to form a pre-twisted yarn 3a. Further, as shown in FIG. Is twisted in the reverse direction with a twisting coefficient of 3.2 to 4.2 to obtain a core body 3 having a total denier number D in the above range. Occupancy rate of 75
It is a configuration that is buried along the bottom of the tooth portion 2 at ~ 95%.

FIG. 2 shows a toothed pulley 11 around which the toothed belt B is wound. The pulley 11 has teeth 12, 12,... A groove 13 in which the belt teeth 2 are meshed between 12
Are formed. And the groove depth H of this pulley 11
With respect to (unit mm), the height h (unit mm) of the tooth portion 2 of the belt B is set to 1.00H <h <1.02H.

More preferably, the above-mentioned aramid fiber is obtained by heating and drawing so that the crystal orientation angle is about 9 °.

Hereinafter, the reasons for limiting the numerical values will be described in detail in order. First, the hardness of the polyurethane resin constituting the belt main body 1 is 85 ° to 93 °. In order to increase the durability life of the belt B under high load conditions, the polyurethane resin needs to have sufficient strength.
However, if the hardness exceeds 93 °, the belt is likely to be cracked on the back surface of the belt due to repeated winding around the small pulley, and there is a risk of belt cutting due to the progress of the crack. On the other hand, if the hardness is less than 85 °, the strength of the tooth portion is insufficient, and the durability life is shortened. Therefore, the hardness of the polyurethane resin needs to be 85 ° to 93 °.

Aramid fiber core 3 is used as the tensile member. Aramid fibers have a higher modulus of elasticity than glass fibers, so that the belt tooth pitch can be more accurately maintained when a load is applied.

Further, by providing the belt tooth portion 2 with a reinforcing material layer 4 such as a woven fabric, a knitted fabric, or a non-woven fabric, the fatigue strength of the tooth portion 2 can be increased.

FIG. 5 shows load durability evaluation results obtained by changing the belt Young's modulus. The test apparatus has the configuration shown in FIG. 4, in which a toothed belt B is wound around a pair of toothed pulleys 11. In the belt B, the pitch P of the teeth 2 is P = 14 mm, the hardness of the polyurethane resin of the belt body 1 is 90 °, the teeth 2 are reinforced with a nonwoven fabric, the shape of the teeth 2 is an arc tooth shape, and the tooth height is h has a tensile strength of aramid fiber core 3 with h = 4.65 mm and 100 ^T teeth. Each pulley 11 is 28 ^T -28 ^T ,
A tooth groove depth H of 4.95 mm was used. The pulley rotation speed is 1900rpm, the load torque is 15kgfm,
The test was performed for two belt widths of 15 mm and 12 mm.
The variation of the belt Young's modulus was determined by the total denier, twist coefficient, and heat stretching of the aramid fiber core 3. The pitch of the core 3 is 2.5 mm. The twist coefficient TM is represented by the following equation.

TM = t · d ^1/2 / K where t: number of twists per inch d: denier of cord K: material constant (68 for aramid fiber) Aramid fiber is PPTA (polyparaphenylene terephthalamide fiber) And a crystal having an orientation angle OA of about 15 ° and a crystal having an orientation angle OA of about 9 ° obtained by heating and stretching this by about 5%. The belt Young's modulus was measured at a tensile speed of 50 mm / min with a belt B wound around a 28 ^T- 28 ^T pulley attached to a tensile tester. Since the cross section of the belt B is not a uniform material, a value AE obtained by multiplying the elastic modulus E by the cross-sectional area A is defined as the belt Young's modulus for convenience. Heart 3
Are filament denier 1.4de and 2.25d
e and two types were used. The configuration of the core body 3 is such that the filament bundle obtained by bundling the filaments has a twist coefficient T
M was used for twisting, and several of the twisted yarns were aligned and then twisted in the opposite direction to the twisting with the same twisting factor TM as the twisting coefficient TM. As shown in FIG. 5, the belt durability life is dramatically improved by increasing the Young's modulus.

Next, FIG. 6 shows the results of the evaluation of flex fatigue.
At this time, the test apparatus is basically the same as that of FIG. 4. Both pulleys 11 and 11 are arranged vertically, and one pulley 11 is given a weight of 80 kgf to apply belt tension. The pulley 11 was 18 ^T- 18 ^T , the belt width was 15 mm, the pulley rotation speed was 3600 rpm, and the vehicle was run with no load. The other conditions were the same as those at the time of the test in FIG. 5, and were performed for two types of core twisting coefficients TM = 3.4 and 4.8. As shown in FIG. 6, the strength after bending shows a tendency to sharply decrease from around 10 ⁷ times of bending.
The conditions of use in the market vary, but are approximately 10 ⁸ to 2 ×
The standard is about 10 ⁸ times. Therefore, in order for the belt B to travel without being cut, there is no problem as long as the belt B has a strong retention of about 50% in 10 ⁸ times. From the tendency of the bending fatigue property to decrease as shown in FIG. 6, if the strength retention is about 80% at 2 × 10 ⁷ times, the strength retention at 50% can be estimated at 10 ⁸ times. Therefore, a strong retention of 80% at 2 × 10 ⁷ times is considered as one index.

Based on this idea, the twist coefficient TM = 4.
The eight can also be used with an 18 ^T pulley. However, as shown in FIG. 5, when the twist coefficient TM = 4.8, the belt Young's modulus is insufficient and the tooth shear life is low.
Thus, in order to use the belt with a small pulley while improving the life of the belt, it is understood that the belt Young's modulus and the flex fatigue must be compatible by selecting an appropriate core body specification.

In order to achieve both belt Young's modulus and flex fatigue, the twist coefficient of the core body 3 is set to TM = 3.2 to 4.2.
And FIG. 7 shows changes in the belt Young's modulus and flex fatigue due to the change in twist coefficient. As shown in FIG. 7, when the twist coefficient TM = 2.0, the Young's modulus is high, but the bending fatigue property is very low. Further, when the twist coefficient TM is 4.8, the bending fatigue property is high, but the Young's modulus is low. In order to achieve both Young's modulus and flex fatigue, the twist coefficient is TM = 3.2.
It needs to be in the range of ~ 4.2. The test shown in FIG. 7 was performed with the same twisting coefficient in the opposite direction between the upper twist and the lower twist. In the case of a rubber belt, since the wear between lower twisted yarns greatly affects the reduction in strength, when twisting the upper twist and the lower twist in opposite directions, the angle of intersection of the filaments between the lower twisted yarns increases, and it becomes easier to wear. Although there is a problem, in the case of a polyurethane resin belt, the polyurethane resin is sufficiently filled between the ply-twisted yarns, and there is almost no reduction in the strength due to wear between the ply-twisted yarns. Does not affect much. As an example, the bending fatigue property was examined under the same conditions as in FIG. 7 under the same conditions as in FIG. 7 with a denier of 4500 denier, a number of upper twists of 5, a twist factor TM of 3.4, and no twist. Met. Since the one with the vertical twist coefficient TM = 3.4 shown in FIG. 7 had a strength retention of 60%, it was found that the lower twist coefficient had almost no effect. However, since the lower twist coefficient tends to lower the belt Young's modulus as it increases, the lower twist coefficient is at most the same as the upper twist coefficient. On the other hand, if it is too small, the balance of the twisting of the core body itself will be poor, and there is a possibility that the belt will meander. Therefore, the twist coefficient is TM =
It is set between 1.2 and 4.2.

Next, the reason why the number of twists on the core body is set to 5 will be described. FIG. 8 is a graph showing the change characteristics of the belt Young's modulus and the bending fatigue property with respect to the change in the number of twists on the core body. To remove other factors, the total denier is 284
100 to 29820 denier and the twist coefficient is T
Fix M = 3.4 and set filament denier to 1.4d
e, the number of twisted yarns was changed by changing the ratio of the number of twisted yarns to the number of denier yarns (number of filaments). As the twisted core body for the transmission belt of the aramid fiber, three twists are most often used. As shown in FIG. 3 (a), this is the most stable configuration for the twisted yarn 3a, so that the alignment of the twisted yarn 3a is the best, and as a result, fluctuations in strength and elastic modulus are small and reliability is improved. For good reasons. The next stable number is shown in FIG.
5 twists. The five-ply twist is used as a part because it has a considerably stable configuration, although not as much as the three-ply twist. Further, the six twists shown in FIG. 3 (c) and the number of twists exceeding this are extremely unstable, and the lower twist yarn 3
They are hardly used because of poor alignment of a and poor reliability. As shown in FIG. 8, the belt twist is not much different in the 5-twist as compared with the 3-twist, but the flex fatigue is remarkably high. When the number of twists is 7 or more, the bending fatigue property is good, but the elastic modulus tends to be greatly reduced. Further, in the case of six strands, the strength and the elastic modulus vary greatly as described above, and there is a problem in reliability. Therefore, the number of twists on the core is five.

Next, FIG. 9 is a graph showing a change characteristic of the belt Young's modulus and the bending fatigue property according to the change of the filament denier. To remove other factors, the total denier D
Is fixed to 28400 denier, and the twist coefficient is TM =
3.4 The number of ply-twisted yarns was kept constant at 5, and the number of ply-twisted filaments was changed to change the number of ply-twisted yarns to change the filament denier. As shown in FIG. 9, the filament having a denier of 1.4 de has a retention rate as high as 12% as compared with the filament having a denier of 2.1 de. From FIG. 9, it is understood that the filament denier is preferably 1.6 de or less. However,
If the filament denier is less than 0.9 de, stable denier cannot be obtained in the production of the fiber, and the fiber lacks reliability. Therefore, a filament denier of 0.9 to 1.6 de is selected.

Next, FIG. 10 is a graph showing a change characteristic of the bending fatigue property according to the change of the belt tooth height. At this time, the specifications of the core were fixed at 1.4 den of filament denier, 5680 de denier of twisted yarn, TM = 3.4, twisted number of 5, twist coefficient TM = 3.4, and only belt tooth height. Variable. As compared to the design in which a gap of 6% is provided with respect to the tooth height h as shown in FIG. 10, the 12% retention is improved at ± 0%. Further compression by 1% improves 8%. If the belt tooth height is higher than the pulley groove depth, the belt
When the roller is wound around the pulley 11, the belt tip is brought into contact with the tooth tip, and the bottom of the belt is raised above the top of the pulley. It will be a good engagement. However, if the belt tooth height is increased by 2% or more, the belt will be in a floating state even when the initial tension is applied, and the PLD (pitch line difference) does not match. Would. Therefore, the belt tooth height h is preferably in the range of 1.00H <h <1.02H with respect to the pulley groove depth H. Until now, most of the polyurethane resin toothed belt has been set to satisfy H> h, but by setting the above range, the bending fatigue property can be improved.

Next, FIG. 11 is a graph showing the belt Young's modulus and flex fatigue according to the change in the total denier number D of the core.
To remove other factors, filament denier 1.
The total denier number D of the core was varied by changing the number of deniers d of the lower twisted yarn while fixing 4 de, the number of upper twists, the twist coefficient TM = 3.4, and the belt tooth height at 5.00 mm. Also, taking into account that if the total body denier number D is reduced, a large number of cores can be embedded per unit width, the occupancy of the core is fixed at about 85%. The occupancy is the ratio of the occupied portion of the core to the belt width. Occupancy (%) = (Cp / Cd) × 100 where Cp: core pitch Cd: core diameter (mm) You. The core body diameter Cd is as follows: Cd = 2 {16 × D / (π ³ × 9 × 10 ³ × S)} 1/2 where D: total denier number S: specific gravity (PPTA is 1.44 to 1.47) ). This occupancy of the body is set at 75 to 95%. In other words, if the occupation ratio is 75% or less, a sufficient elastic modulus cannot be obtained, while if it exceeds 95%, delamination tends to occur between the tooth portion 2 and the tensile member layer. Is shortened.

Referring again to FIG. 11, if the total Young's number D is 16,000 denier or more, the belt Young's modulus can be maintained at 7500 kgf / 15 width or more, so that a long tooth part shear life can be maintained. Conversely, with regard to flex fatigue, if the total denier number D is 24000 or less, the strength retention is about 80%, so a 50% retention can be estimated even with 10 ⁸ bends. Therefore, 14mm
In a toothed belt with a pitch, the total denier number D of the body is D = 1.
It is set in the range of 6000 to 24000 denier. Furthermore, since the number of upper twists is 5, the number d of lower twist yarns is set in the range of d = 3200 to 4800.

Here, even if the toothed belt is of the same type, there are several different tooth pitches depending on the load torque. For example, tooth pitches of 11 mm, 8 mm, 5 mm, 3 mm, etc. are industrialized in addition to the above 14 mm. In the case of improving the toothed belt core body, the above twist coefficient can be applied to any pitch, but the total denier number D and the lower twist yarn denier number d are set according to each pitch. Things. The present invention is not intended only for a toothed belt having a pitch of 14 mm, but by improving the bending fatigue resistance while increasing the belt Young's modulus at any pitch, it is an improvement that can be used with a smaller pulley. is there. In general,
When the pitch is different between the toothed belts of the same type, the belt shape changes substantially similar in proportion to the pitch. Therefore, the total denier number D and the lower twist yarn denier number d can be generalized by the square of the belt pitch P × constant.

Therefore, the total denier D is, as described above, D = 16000 for a toothed belt having a pitch of 14 mm.
Generalized to ~ 24000 denier, 82P ² <D
<It is set in a range of 122P ^2. Similarly, the number d of the lower twist yarn denier is 14 mm pitch and d = 3200 to 4800 d.
Generalized by e, 16.3P ² <d <24.5P ²
Is set in the range.

For example, in the case of a toothed belt having a pitch of 8 mm,
The total denier D is set to D = 5200 to 7800 de, and the lower twist denier d is set to d = 1050 to 1560 denier.

In the toothed belt B configured as described above, the increase in the belt Young's modulus allows both the improvement of the shear life of the tooth portion 2 and the improvement of the bending fatigue, thereby improving the tooth portion shear life of the belt. In addition, it is possible to improve the cutting life and to enable use with a small pulley or high rotation.

(Specific Example) In order to explain that the present invention is very effective, evaluation results of load durability and flex fatigue of the present invention and some comparative examples are shown. In the load durability evaluation test, the belt width was varied under the same conditions as in FIG. The evaluation test of the bending fatigue resistance, the pulley number of teeth ^{18 T -18 T, 22 T -22} T, 28 T -28 T and is variable, the other conditions were the same as FIG.

The belts were all toothed belts with a pitch of 14 mm, the number of teeth was 100 ^T , and the teeth were arc-shaped. Inventive Examples and Comparative Examples 1 and 2 are polyurethane resin belts, all of which have a hardness of 90 °, and whose core is made of aramid fiber.

The core of the example of the present invention is PPTA, and an aramid fiber having an orientation angle OA of about 9 ° is obtained by heating and drawing about 5% of a raw yarn having an orientation angle OA of about 15 ° of the crystal (about 9 °) ( This is commercially available from Toray Dupont Kevlar under the trade name "Kevlar 49"). The filament denier was 1.4 denier, and the number d of the lower twist yarn was d = 4,560 denier (four bundles of the commercially available raw yarn denier number 1,140 de were used). This was twisted with a twisting coefficient TM = 3.4 and then twisted with five twists and twisted with TM = 3.4. The core pitch was 2.2 mm and the occupancy was 86%.

The core of Comparative Example 1 is an aramid fiber having the same crystal orientation angle OA as that of the present invention of 9 °, the filament denier is 1.4 de, and the number of denier of the lower twist yarn d = 568.
0de (1420de × 4 wires), number of twists is 5, twist factor TM = 3.4, occupancy ratio at core pitch Cp = 2.5 mm, 8
5%. The core of Comparative Example 2 has a crystal orientation angle OA = 1.
1. Aramid fiber of 5 ° (trade name “Kevlar 29” manufactured by Dupont Kevlar Toray) and filament denier
25 de, the number of deniers of the lower twist yarn d = 4500 de (22
50de × 2), number of twists: 5, twist coefficient TM = 4.
8. The core pitch Cp = 2.5 mm and the occupancy is 76%.

Comparative Example 3 is a rubber belt whose core is made of glass fiber, which is widely used.

FIG. 12 is a graph showing the load durability when the width of each belt varies. As shown in FIG. 12, a commercially available rubber belt of Comparative Example 3 was compared with the present invention and Comparative Examples 1 and 2.
In No. 2, the durability life is very long. This is because the belt main body is made of polyurethane resin having high fatigue strength, and the teeth are reinforced with fibers. Furthermore, in the present invention example and the comparative example 2, the durability life is several times longer than that of the comparative example 3. This is because the belt Young's modulus was greatly increased. In addition, the inventive examples and the comparative example 2 are close to each other in the Young's modulus, so that the durability life is also close.

FIG. 13 is a graph showing the bending fatigue of each belt depending on the number of pulley teeth. As shown in FIG. 13, the present invention example and comparative example 2 have a strong retention rate of 80 even with an 18 ^T pulley.
%, So that it can be used without trouble with a small pulley of 18 ^T. Comparative Example 1 has a long tooth shear durability life, but cannot be used unless it is 28 ^T pulley or more. The commercially available rubber belt (Comparative Example 3) gives worse results.

Thus, as described above, only the example of the present invention has a long durability life in shearing of the tooth portion and a good bending fatigue property, thus supporting that it can be used with a small pulley and under a high load condition.

[0047]

As described above, according to the first aspect of the present invention, an aramid fiber core is buried as a tensile member in a belt body made of a polyurethane resin along a tooth bottom, and a woven fabric is High load transmission toothed belt having a reinforcing material layer such as
The filament of 1.6 de is transferred to the belt tooth pitch P.
Filament bundles of several hundreds to thousands bundled so that the denier number d of 16.3P ² <d <24.5P ² with respect to (unit mm) is ply twisted with a ply twist coefficient of 1.2 to 4.2. the twist yarn composed is, the twist direction five draw aligned with it to final twists in 3.2 to 4.2 above twist factor in the reverse direction, Traction total denier number D is 82P ² <D < configure a 122P ² above aramid fiber tension member, because the aramid fiber tension member to a tension member occupancy 75% to 95% with respect to the belt width is obtained by embedded along the tooth bottom, a tooth by increasing the belt Young's modulus With a high load transmission tooth made of polyurethane, which achieves both improved shear life of parts and improved bending fatigue, has a long tooth shear life, high bending fatigue, and can be used even with small pulleys and high rotations. Belt can be realized.

According to the second aspect of the present invention, the belt tooth height h is set to 1.00H <h <with respect to the pulley groove depth H.
Since 1.02H is set, a normal meshing state between the belt groove portion and the pulley tooth portion can be obtained, and the bending fatigue property can be further improved.

According to the third aspect of the present invention, since the orientation angle of the aramid fiber crystal in the core body is set to about 9 °,
The above effects can be obtained effectively.

[Brief description of the drawings]

FIG. 1 is a front view partially showing a toothed belt according to an embodiment of the present invention.

FIG. 2 is a front view showing a part of a pulley.

FIG. 3 is a sectional view of a core body showing a change in the number of twists.

FIG. 4 is a schematic diagram of a belt tester.

FIG. 5 is a characteristic diagram showing a relationship between a change in the Young's modulus of the belt and durability.

FIG. 6 is a characteristic diagram showing evaluation of flex fatigue.

FIG. 7 is a characteristic diagram showing a relationship between a change in twist coefficient of a core body, a belt Young's modulus, and flex fatigue.

FIG. 8 is a characteristic diagram showing a relationship between a change in the number of twists of the core body, the belt Young's modulus, and flex fatigue.

FIG. 9 is a characteristic diagram showing a relationship between a change in core filament denier and a belt Young's modulus and flex fatigue.

FIG. 10 is a characteristic diagram showing a relationship between a change in belt tooth height and flex fatigue.

FIG. 11 is a characteristic diagram showing a relationship between a change in the total denier of the heart and the belt Young's modulus and flex fatigue.

FIG. 12 is a characteristic diagram showing a relationship between a change in belt width and load durability in a specific example of the present invention.

FIG. 13 is a characteristic diagram showing a relationship between a change in the number of pulley teeth and flex fatigue according to a specific example of the present invention.

[Explanation of symbols]

 B Toothed belt 1 Belt main body 2 Tooth 3 Core 3a Under twisted yarn 4 Reinforcement layer 11 Toothed pulley P Tooth pitch d Number of under twisted yarn D Total number of cores denier h Belt tooth height H Pulley groove depth

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) F16G 1/00-5/20 D02G 1/00-3/48

Claims (3)

(57) [Claims] An aramid fiber core as a tensile member is buried along a tooth bottom in a belt body made of a polyurethane resin having teeth at regular pitches on an inner surface, and a woven cloth or a knitted cloth is formed on the teeth. In the high load transmission toothed belt on which a reinforcing material layer such as a nonwoven fabric is formed, the aramid fiber core has a filament denier of 0.1%.
The filament having a diameter of 9 de to 1.6 de is set to 16.3 P ² <d <24.5 with respect to the belt tooth pitch P (unit: mm).
The twist yarn of denier d a filament bundle of a bundle of several hundred several thousand so of P ² is formed by twist under twist factor 1.2 to 4.2, and direction twist five pull aligned with Is twisted in the reverse direction with a twist factor of 3.2 to 4.2, so that the total core denier number D is set to 82P ² <D <122P ² , and the core body occupancy ratio to the belt width is 75 ~ 9
A toothed belt for high-load transmission, wherein the belt is embedded along the tooth bottom at 5%. 2. The height according to claim 1, wherein the belt tooth height h (unit mm) is set to 1.00H <h <1.02H with respect to the pulley groove depth H (unit mm). Toothed belt for load transmission. 3. The toothed belt for high load transmission according to claim 1, wherein the aramid fiber core is made of aramid fiber whose crystal orientation angle is set to about 9 ° by heat drawing.