JP2002013594A - Heavy-duty power transmission v-belt - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heavy-duty power transmission V-belt B comprising a tension band 1 having a core-wire 3 and a geometry hold rubber layer 2, and a plurality of blocks 10 locked by engagement with the tension band 1 and arranged in the direction of the belt length, in which a permanent set of the tension band 1 is restrained while maintaining an elastic modulus thereof, thereby preventing fatigue and enhancing durability for the core-wire 3, then suppressing heat generation and reducing noise level. SOLUTION: The geometry hold rubber band 2 is designed to have 60 MPa or greater and 85 MPa or less of storage modulus, under conditions of temperature 100 deg.C, static load 0.29 MPa, dynamic strain 1%, frequency 10 Hz, and pulling mode, and further to have 60% or less of compressive permanent set after 24 hours under condition of compressibility 10% and temperature 120 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-load transmission V-belt, and more particularly to a high-load transmission V-belt in which a number of blocks are continuously mounted in the longitudinal direction of a tension band.

[0002]

2. Description of the Related Art Conventionally, such a high-load transmission V-belt has been used, for example, in the field of continuously variable transmissions. The continuously variable transmission is configured by winding the high-load transmission V-belt between at least two drive pulleys, each of which includes a fixed sheave and a movable sheave, on a driving side and a driven side. This high load transmission V-belt is, for example,
As shown in JP-A-69490, a large number of blocks are connected to an endless tension band having a configuration in which a core wire is passed through a shape-retaining rubber layer made of hard rubber so as to be continuous in the longitudinal direction of the tension band. It is fixed and configured.

[0003] The block comprises an upper beam extending in the belt width direction, a lower beam narrower than the upper beam,
It is formed in a substantially H-shape from a center pillar that connects the left and right central portions of both beams up and down. And the tension band, between the upper beam and lower beam of the block,
The center pillar is mounted so as to be in contact with the center pillar by being inserted from both sides.

[0004] In this type of V-belt, in order to ensure the easiness of bending, each block is not bonded to the tension band, and the convex portions formed on the upper and lower beams of the block and the upper and lower portions of the tension band are not bonded. It is configured to lock the concave portion formed on the surface. The block and the tension band are fixed in such a physically locked state (meshed state) so that power is transmitted and received between the tension band and each block.

On the other hand, in the V-belt, for example, the mesh thickness of the tension band (the distance between the upper surface and the lower surface) is set to be larger than the mesh gap of the block (the distance between the upper beam and the lower beam). An interference is provided so that the tension band is inserted and fitted into the fitting portion of the block while being compressed in the thickness direction. The initial tightening that occurs when the tension band is pressed into the block when assembling the belt keeps the play between the tension band and the block at the required level and suppresses noise rise, block wear, and core wire fatigue. I am trying to do it.

Further, for example, a protrusion is provided in the tension band so as to protrude from the side surface of each block by about 100 μm, and this protrusion reduces the impact of the block from entering the pulley, thereby reducing noise during belt running. May be planned. In other words, both the block side surface and the tension band side surface are in contact with the pulley groove surface, and the side pressure from the pulley is shared and received by the block and the tension band. It is alleviated by the protrusion at the side of the tension band, making it difficult for rattling between the block and the tension band to occur, and also alleviating the generation of noise.

[0007]

By the way, in order to enable high load transmission and to reduce fatigue of the cord of the tension band,
It is necessary to increase the elastic modulus of the crosslinked rubber to a certain extent. For this reason, hydrogenated nitrile rubber reinforced with zinc methacrylate has been often used for the shape-retaining rubber layer in the tension band. Further, in order to increase the modulus of elasticity, the amount of zinc methacrylate in the shape-retaining rubber layer is usually set to 40% by mass or more.

[0008] On the other hand, a conventional shape-retaining rubber layer containing the amount of zinc methacrylate in the above-mentioned ratio (40% by mass or more) satisfies the condition relating to the elastic modulus, but has a large compression set. Therefore, in the running process of the belt, the locking portion of the tension band tends to set (age) over time. As a result, the engagement between the tension band and the block becomes loose, causing rattling of the block, which may cause fatigue of the core wire of the tension band, or increase in noise due to swinging of the block. There was a case.

Further, since the heat resistance of the cross-linked rubber material is low in the conventional material, cracks in the shape-retaining rubber layer tend to occur relatively early during belt running, and as a result, fatigue and breakage of the core wire occur. There was also a disadvantage that it became easier.

[0010] By increasing the above-mentioned closing margin and allowance,
It is considered that the rattling of the block is reduced, and the generation of noise can be suppressed for a relatively long period. However, in this case, since the frictional resistance is increased, the heat generated in the initial stage of traveling, particularly when the belt is not adapted to the pulley, may be increased. Further, even in this case, if the tension band wears over time and the protrusion is reduced, noise increases.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has as its object to secure sagging (aging) while ensuring the elasticity of a tension band in a V belt for high load transmission. Therefore, the core wire is prevented from being fatigued, durability is improved, and heat generation and noise are also suppressed.

[0012]

The present invention is characterized in that the elastic modulus and compression set of the shape-retaining rubber layer are specified within predetermined ranges.

Specifically, a first solution taken by the present invention is to provide a tension band formed by embedding a core wire inside a shape-retaining rubber layer;
It is assumed that a high-load transmission V-belt composed of a plurality of blocks arranged in the belt length direction by engaging with and engaging with the tension band. Then, the storage elastic modulus of the shape-retaining rubber layer in the belt length direction was measured at a temperature of 100 ° C. and a static load of 0.
Under the conditions of 29 MPa, dynamic strain 1%, frequency 10 Hz, and tensile mode, the pressure is 60 MPa or more and 85 MPa or less, and the compression set is 10% and the temperature is 120 ° C., and the compression set after 24 hours is 60% or less. It is.

[0014] A second solution taken by the present invention is:
In the first solution, the shape-retaining rubber layer is formed from a hydrogenated nitrile rubber reinforced with a metal salt monomer,
The Mooney viscosity of nitrile rubber is set to 120 ML1 + 4 (10
0 ℃ or more and 200 ML1 + 4 (100 ° C.) or less.

[0015] A third solution taken by the present invention is:
In the first or second solution, the shape-retaining rubber layer is formed from a hydrogenated nitrile rubber reinforced with a metal salt monomer, and the metal salt monomer is contained in a proportion of 20% by mass or more and 35% by mass or less. It was made.

A fourth solution taken by the present invention is:
In the second or third solution, the metal salt monomer is zinc acrylate or zinc methacrylate.

Further, a fifth solution taken by the present invention is:
In any one of the second to fourth solving means,
The shape-retaining rubber layer is reinforced by at least one filler selected from the group consisting of carbon black, silica, and calcium carbonate / talc.

A sixth solution taken by the present invention is:
In any one of the second to fifth solving means,
The shape-retaining rubber layer contains zinc oxide at a ratio of 20 parts by mass or more and 40 parts by mass or less per 100 parts by mass of the hydrogenated nitrile rubber reinforced with the metal salt monomer.

[0019]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 shows a high-load transmission V-belt B according to an embodiment of the present invention. The belt B has a pair of left and right endless tension bands 1 and 1 and a belt longitudinal direction. Blocks 10,10,10,10,10
…. As shown in FIGS. 2 and 4 in an enlarged manner, each tension band 1 has a shape-retaining rubber layer 2 made of hard rubber.
A high-strength, high-modulus core wire 3 such as an aramid fiber (braid) in a spiral shape is arranged and buried inside. The upper surface of each tension band 1 corresponds to each block 10. The groove-shaped upper recesses 4, 4,... Extending at a constant pitch in the belt width direction, and the lower recesses 5, 5 extending at a constant pitch corresponding to the upper recesses 4, 4,. ,... Are respectively formed. In addition, tension band 1
The upper and lower surfaces of the canvas 6, 6, 6 are provided for the purpose of preventing cracks and improving wear resistance.
Are integrally bonded.

The hard rubber forming the shape-retaining rubber layer 2 is as follows:
Hydrogenated nitrile rubber reinforced with metal salt monomers such as zinc methacrylate and zinc acrylate, and has excellent heat resistance by reinforcing organic short fibers 7,7,. Hard rubber which is hard to be permanently deformed is used. As described above, by using the hydrogenated nitrile rubber reinforced with zinc methacrylate as the rubber of the shape-retaining rubber layer 2, a rubber for the shape-retaining rubber layer 2 that is hard and has excellent wear resistance can be obtained. The hard rubber has a rubber hardness of 75 ° or more as measured by a JIS-C hardness tester.

The organic short fibers 7 are, for example, 6, 6
Nylon fiber, 6 nylon fiber, 4,6 nylon fiber,
Short fibers, such as aramid fibers, polyester fibers, and vinylon fibers, having a lower coefficient of friction with the pulley groove surface (not shown) than the rubber of the shape-retaining rubber layer 2, and are oriented in the belt width direction. Further, when it is necessary to increase the gripping force of the rubber against the core wire 3 to improve the durability of the tension band 1 and to provide a high rubber elastic modulus in the width direction so that the tension band 1 shares the side pressure from the pulley. It is preferable to use aramid fiber, PBO (polyparaphenylene benzobisoxazole) fiber or the like in addition to the nylon fiber.

The shape-retaining rubber layer 2 and the cords 3 and the canvases 6 are firmly adhered to each other at the time of rubber cross-linking by an appropriate bonding treatment to the cords 3 and the canvases 6 to be integrated. I have.

As a feature of this embodiment, the shape-retaining rubber layer 2
Means that the storage elastic modulus in the belt length direction (the direction perpendicular to the orientation direction of the polymer chain) is 100 ° C., static load 0.2
Under the conditions of 9 MPa, dynamic strain 1%, frequency 10 Hz, and tensile mode (by Rheometrics RSAII),
It is set so that the compression set is 60 MPa or more and 85 MPa or less, and the compression set (according to JIS K6262) after 24 hours under the conditions of a compression rate of 10% and a temperature of 120 ° C. is 60% or less.

The shape-retaining rubber layer 2 is made of a hydrogenated nitrile rubber reinforced with zinc acrylate or zinc methacrylate (metal salt monomer) as described above, and the nitrile rubber preferably has a Mooney viscosity of 120 ML1.
+4 (100 ° C) or more and 200ML1 + 4 (100 ° C)
It is set as follows.

The shape-retaining rubber layer 2 is preferably composed of a rubber composition containing a polymer containing the above-mentioned metal salt monomer in a proportion of 20% by mass or more and 35% by mass or less. Further, the shape-retaining rubber layer 2 is preferably reinforced by at least one filler selected from the group consisting of carbon black, silica, and calcium carbonate / talc. Further, the shape-retaining rubber layer 2 preferably contains zinc oxide at a ratio of 20 parts by mass or more and 40 parts by mass or less per 100 parts by mass of the hydrogenated nitrile rubber reinforced with the metal salt monomer.

On the other hand, as shown in an enlarged manner in FIGS. 2 and 3, each block 10 has a notch shape for detachably fitting each of the tension bands 1 on the left and right sides in the belt width direction from the width direction. Of the fitting groove 1
Abutment portions 1 that contact the pulley groove surface on the left and right side surfaces except 1
4,14. By fitting the tension bands 1, 1 into the fitting grooves 11, 11 of each block 10, the blocks 10, 10, ... continuously mesh with the tension bands 1, 1 in the belt longitudinal direction. It is locked.

Specifically, on the upper wall surface of each fitting groove 11 in each block 10, there is provided an upper convex portion 12 formed of a ridge meshing with each upper concave portion 4 on the upper surface of the tension band 1. On the lower wall surface of the groove 11, each lower recess 5 on the lower surface of the tension band 1 is provided.
Are formed in parallel with each other. Then, the upper and lower convex portions 12 and 13 of each block 10 are respectively connected to the tension band 1.
By engaging the upper and lower concave portions 4 and 5 of the block 1,
Are locked to the tension bands 1 and 1 in the longitudinal direction of the belt.

Each of the blocks 10 is basically made of a thermosetting phenol resin material, which is a hard resin. As shown in FIG. , A high-strength, high-elasticity reinforcing member 15 made of a lightweight aluminum alloy or the like is embedded. The reinforcing member 15 includes, for example, the upper and lower convex portions 1.
2, 13 (the meshing portion with the tension band 1) and the contact portions 1 on the left and right side surfaces
In the portions 4 and 14 (contact portions with the groove surface of the pulley), they are embedded in the hard resin and do not appear on the surface of the block 10 (that is, these portions are made of the hard resin). May be exposed.

The reinforcing member 15 is composed of upper and lower beams 15a and 15b extending in the belt width direction (left and right direction), and a center pillar 15c for connecting the left and right central portions of both beams 15a and 15b up and down. About H
It is formed in a character shape. Then, the reinforcing member 15 is inserted into a thermosetting phenol resin to form a block 10.
Is formed, and further, if necessary, various forming processes are added to increase the strength of the block 10.

Further, in advance, the engagement thickness t2 between the upper and lower concave portions 4 and 5 of the tension band 1 made of the hard rubber, that is, FIG.
The distance between the bottom surface of the upper concave portion 4 (specifically, the upper surface of the upper canvas 6) and the bottom surface of the lower concave portion 5 (the lower surface of the lower canvas 6) corresponding to the upper concave portion 4, as shown in FIG. , That is, the distance between the lower end of the upper protrusion 12 and the upper end of the lower protrusion 13 of each block 10 shown in FIG. 3 is slightly larger by, for example, about 0.03 to 0.15 mm (t2>).
t1) It has been set. For this reason, at the time of assembling each block 10 to the tension band 1, the tension band 1 is compressed and assembled in the thickness direction by the block 10, whereby the interference t2
−t1 (initial press-fitting of the tension band 1 to the block 10)
Is provided.

As shown in FIG. 2, on the pulley contact surfaces on both the left and right sides of the belt B, the side surface 1a on the outer side in the belt width direction of the tension band 1 is formed by the abutting portions 14, 14 made of resin of each block 10. Slightly more than the surface (for example, 0.03 to
0.15 mm). Thus, a protrusion Δd for the tension band 1 is provided so that both the outer side surface 1a of each tension band 1 and the contact portions 14 on the left and right sides of each block 10 contact the pulley groove surface. Have been.

When the belt B is assembled, the protrusion Δd is determined by the contact portion 14 on the side surface of the block 10 and the tension band 1.
Of the tension band 1 (the width on a plane passing through the core wire 3).
Can be adjusted freely with respect to the insertion pitch width of the fitting groove 11 (the groove depth at the position of the core wire 3 of the tension band 1 fitted into the fitting groove 11), which is the meshing portion of the block 10. Can be changed to Each tension band 1 is press-fitted into the fitting groove 11 of each block 10 and inserted. In order to complete the press-fitting, the tension band 1 is applied by the belt B with a force greater than the force received from the pulley in actual use. It is necessary to press-fit. This margin Δd can be easily measured by scanning the left and right side surfaces of the belt B after assembly with a contracer (contour shape measuring device).

Since the side surface 1a of each tension band 1 protrudes from the contact portion 14 on the side surface of each block 10, a protrusion Δd is formed. The block 10 and the tension band 1 share and receive the side pressure from the pulley by contacting the pulley groove surface together with the contact portion 14, and the impact when each block 10 enters the pulley groove is applied to the side of the tension band 1. Alleviated by the part.

[0035]

Next, specific embodiments will be described. The high load transmission V-belt has a belt angle of 26 degrees, a belt pitch width of 25 mm, a block pitch (belt length direction) of 3 mm, a block thickness of 2.95 mm, and a belt length of 6 mm.
It was 12 mm.

The rubber used for the tension band had the basic composition shown in Table 1 below. That is, one of two types of hydrogenated nitrile rubber was selected as the matrix rubber of the belt tension band, and the nitrile rubber was reinforced with zinc methacrylate or zinc acrylate. Also,
The rubber contains a predetermined amount of zinc oxide, a filler composed of calcium carbonate, silica, and carbon black (these may be used in combination of at least one of them), an antioxidant, sulfur, and peroxide. did. Nylon short fibers and aramid short fibers were added to the rubber at the ratios shown in Table 1 and kneaded to prepare a short fiber reinforced rubber. This was rolled by a calender to orient the short fibers in the rolling direction. Then, using this rubber sheet, a tension band was processed into a predetermined shape so that the belt width direction was the orientation direction of the short fibers.

[0037]

[Table 1]

In Table 1, the Mooney viscosity of the hydrogenated nitrile rubber is 85 ML1 + 4 (100
° C), and the Mooney viscosity of the hydrogenated nitrile rubber is 120 ML1 + 4 (100 ° C). Further, the compounding amount indicates a ratio to 100 parts by mass of the hydrogenated nitrile rubber reinforced with zinc methacrylate or zinc acrylate.

On the other hand, the block is manufactured by insert-molding a reinforcing material made of a lightweight and high-strength aluminum alloy having a thickness of 2 mm into a phenol resin, and performing a heat treatment after the molding so that the physical properties of the resin become a predetermined value. I made it.

As examples and comparative examples, zinc oxide, calcium carbonate, silica, and carbon black were added to a hydrogenated nitrile rubber or a rubber reinforced with a predetermined amount of zinc methacrylate or zinc acrylate. They were blended at different ratios to prepare tension bands of the example and the comparative example. Specifically, each example had the composition shown in Tables 2 to 4 below, and each comparative example had the composition shown in Tables 5 and 6 below.

[0041]

[Table 2]

[0042]

[Table 3]

[0043]

[Table 4]

[0044]

[Table 5]

[0045]

[Table 6]

Further, a durability running test was performed using a belt in which this tension band and the above block were combined. The initial interference of the tension band and the block was 0.07 mm in each of the examples and the comparative examples.

The running test was performed on each of the belts of the comparative example and the example using a heat resistance test apparatus shown in FIG. 5, and the durability of the belt during running was measured. FIG. 5A is a schematic cross-sectional view of the heat resistance test apparatus viewed from the upper side, and FIG. 5B is a schematic cross-sectional view viewed from the front side. This heat resistance test apparatus is provided with a hot air inlet 20a having a diameter of 40 mm at substantially the center of the front upper left and right sides.
However, a heat-resistant box 20 having a hot air outlet 20b having a diameter of 90 mm opened at the left end of the upper surface. A drive pulley 22 having a pitch circle diameter of 126.43 mm provided on the drive shaft 21 is provided on the left side (on the side of the hot air outlet 20 b) in the heat-resistant box 20, and a pitch circle diameter 70. 8 mm driven pulleys 24 are arranged at a distance of 148.5 mm from each other. Then, each belt B of each embodiment and comparative example is wound between these pulleys 22 and 24, and hot air is sent from the hot air inlet 20 a into the heat-resistant box 20 and discharged from the hot air outlet 20 b, and Was run under the conditions shown in Table 7 below.

[0048]

[Table 7]

For each belt B, the interference, temperature and noise after running for 100 hours were measured. Specifically, the temperature of the belt B was measured with a non-contact thermometer after running for 100 hours on the side surface of the tension band.

The noise was measured with the noise test device shown in FIG. 6 after stopping the running of the belt in the heat resistance test device (see FIG. 5) for 100 hours and removing the belt. FIG. 6A shows the noise test apparatus from above,
(B) is the figure seen from the front side, respectively. On the left side of this noise test device, a pitch circle diameter 5 provided on the drive shaft 31 is provided.
A 0.7 mm drive pulley 32 and a driven shaft 3
3 is a driven pulley 3 having a pitch circle diameter of 113.3 mm
4 are arranged at an interval of 174.4 mm between axes. Then, each belt B is wound around these pulleys 32 and 34, and the drive pulley 32 is rotated at 2500 rpm to run the belt B. At this time, the drive shaft 31
The noise at a sound measurement position P 50 mm away from the center and 100 mm away from the front side was measured with a microphone or the like. The specific conditions of the noise characteristic test are shown in Table 8 below.

[0051]

[Table 8]

The results of the noise measurement were expressed as percentages of the ratio of the noise value in each example to the noise value (dB) in Comparative Example 1, and were defined as relative values. Further, the endurance running test was continued even after the noise measurement, and the time when cracks occurred in the shape-retaining rubber layer in the tension band and the time when the belt was cut were measured.

The measurement results of the above tests are shown in Tables 2 and 3 above.
Table 6 also shows the physical properties of the crosslinked rubber of each example. Note that, among the physical property values, the heat aging elongation at break elongation ratio is based on JIS K
According to 6257, K6250, K6251, dumbbell-shaped No. 3 type, pulling speed 500 mm / min, measurement temperature: 25
° C, aging conditions: 150 ° C, 168 hours.

As can be seen from these results, all of the examples have a good balance of elastic modulus, compression set, and heat aging resistance, so that the interference is maintained at a predetermined level even after running, and the degree of fixing of the block is high. In addition, the noise is low on average and cracks are unlikely to occur, and the belt has excellent durability.

Specifically, in Comparative Examples 1 to 4, rubber cracks occurred early because of extremely high elastic modulus (especially Comparative Examples 1 and 2), and in Comparative Examples 5 to 14, the elastic modulus was low. For this reason, the belt cutting due to the core wire fatigue occurred early, whereas the elastic modulus was 60 to 85MP in each example.
Since a is set, the belt is hardly cut on average due to core wire fatigue, and rubber cracks are hardly generated for a long period of time (especially, Examples 3 to 18).

In Examples 1 and 2, a hydrogenated nitrile rubber (Mooney viscosity: 120) was used, whereas in Comparative Examples 3 and 4, a hydrogenated nitrile rubber (Mooney viscosity: 85) was used. The differences are the same, and the other composition is the same as in Examples 1 and 2. And Comparative Examples 3 and 4
In Example 1, the value of the compression set was high, so that the tension band was large, and the interference after belt running was loose and noise was large. The permanent set can be suppressed to 60% and the sag of the tension band can be reduced. Therefore, if the Mooney viscosity is set to 120 or more, the interference after belt running is not as loose as in Examples 3 and 4, and it can be seen that noise can be suppressed.

On the other hand, in Example 3, zinc methacrylate was added at 35%.
In contrast, Comparative Examples 1 and 3 contain 50% by mass and 40% by mass of zinc methacrylate, respectively. Moreover, while Examples 11-18 contain 25 mass% of zinc methacrylate or zinc acrylate (metal salt monomer), Comparative Examples 7-14 contain 15 mass% of zinc methacrylate or zinc acrylate. . And Examples 11 to
As can be seen from a comparison between Comparative Example 18 and Comparative Examples 7 to 14, when the amount of the metal salt monomer is small as in Comparative Examples 7 to 14, the elastic modulus decreases, and the belt cutting time is reduced due to the early fatigue of the cord. In contrast, in each of Examples 11 to 18, cutting due to cord fatigue is less likely to occur. Also, as can be seen from Comparative Examples 1 and 3 and Comparative Examples 2 and 4, when the blending amount of the metal salt monomer is large, the compression set becomes large, the interference becomes loose and the noise becomes large. In Example 3 and the like, the compression set is appropriately suppressed, the interference is maintained at a predetermined level, and noise can be suppressed.

In order to increase the elastic modulus to a certain level in Comparative Examples 7 to 14, it is necessary to mix more filler than necessary, and as a result, rubber cracks are likely to occur, and the belt is cut. It becomes easy to do.

Further, for example, as can be seen by comparing Example 3 with Examples 6 to 8, or Example 11 with Examples 14 to 16, 20 to 100 parts by mass of zinc oxide was added. When 40 parts by mass are blended, the heat aging elongation at break elongation ratio increases. That is, in Examples 6 to 8 and Examples 14 to 16, heat resistance is improved and cracks are less likely to occur than in Examples 3 and 11, so that the durability of the belt can be increased. When the amount of zinc oxide is too small, the heat resistance is not sufficiently increased, and when the amount is too large, the crack resistance is reduced. Therefore, as in Examples 6 to 8 and Examples 14 to 16, the zinc oxide is 20 to 40 parts by mass. It is good to

[0060]

As described above, according to the present invention,
Since the storage elastic modulus of the shape-retaining rubber layer in the belt length direction is set in a predetermined range (60 to 85 MPa), both the crack resistance of the shape-retaining rubber layer and the fatigue resistance of the core wire can be achieved. . In other words, if the storage elastic modulus is lower than the above range, the bending fatigue of the core wire is promoted, and if it is higher than this range, cracks occur in the shape-retaining rubber layer at an early stage of traveling, and the stress concentrated on the nearby core wire. Works, and the belt may be cut at an early stage, but such a problem can be prevented. Also, since the permanent compression set of the shape-retaining rubber layer is set to 60% or less, it is possible to suppress the setting of the tension band, maintain the fixed degree of the block, and reduce noise. Further, since the set of the tension band can be suppressed, the initial interference can be reduced, thereby suppressing the heat generation of the belt.

Further, since the Mooney viscosity of the nitrile rubber of the shape-retaining rubber layer is specified to be 120 ML1 + 4 (100 ° C.) or more, the elasticity of the vulcanized rubber is increased, and the settling phenomenon due to creep of the shape-retaining rubber layer is suppressed. Can be Further, if the Mooney viscosity is too high, the processability of the rubber is reduced. However, such a problem can be prevented since the Mooney viscosity is specified to be 200 ML1 + 4 (100 ° C.) or less.

Further, the amount of the metal salt monomer is not less than 20% by mass.
Since it is specified to be 5% by mass or less, the elastic modulus of the vulcanized rubber,
The balance of compression set, heat resistance and crack resistance can be balanced. On the other hand, for example, when the amount of the metal salt monomer is less than the above range, it is necessary to use an excessive amount of a reinforcing filler in order to increase the elastic modulus, and the heat resistance and crack resistance of the shape-retaining rubber layer are reduced. Deteriorates, and the durability of the belt decreases. When the amount of the metal salt monomer is larger than the above range, a predetermined elastic modulus can be obtained even if the amount of the filler is reduced, but the compression set of the crosslinked rubber becomes large, and the tension band becomes large.

By specifying the metal salt monomer as zinc acrylate or zinc methacrylate and specifying the filler as carbon black, silica or calcium carbonate, a shape-retaining rubber layer having excellent durability can be put to practical use. Further, although the present invention specifies the metal salt monomer in the polymer in a relatively small range, if the amount of the filler is appropriately adjusted, the elastic modulus of the shape-retaining rubber layer is not excessively reduced, The compression set can be reduced while setting the optimum range.

When the amount of zinc oxide is small, the heat resistance is not sufficiently improved, and when the amount is large, the crack resistance of the crosslinked rubber is reduced. On the other hand, the amount of zinc oxide is from 20 to 40 parts by mass. By doing so, the heat resistance of the crosslinked rubber is improved, and the generation of cracks at the latter stage of belt running can be suppressed, and the durability of the belt can be increased.

[Brief description of the drawings]

FIG. 1 is a perspective view of a high-load transmission V-belt according to an embodiment of the present invention.

FIG. 2 is an enlarged sectional view taken along line II-II of FIG.

FIG. 3 is an enlarged side view of a block.

FIG. 4 is an enlarged side view of a tension band.

FIG. 5 is a view showing a belt heat resistance test apparatus.

FIG. 6 is a diagram showing a belt noise test device.

[Explanation of symbols]

 B V-belt for high load transmission 1 Tension band 2 Shape-retaining rubber layer 3 Core wire 4 Upper concave portion 5 Lower concave portion 10 Block 11 Fitting groove 12 Upper convex portion 13 Lower convex portion 14 Contact portion (block side surface) 15 Reinforcement Member t1 Mesh gap of block t2 Mesh thickness between upper and lower recesses of tension band t2-t1 Tightening allowance Δd

Claims (6)

[Claims] 1. A tension band in which a core wire is embedded in a shape-retaining rubber layer, and a plurality of blocks arranged in the belt length direction by engaging with and engaging with the tension band. A high-load transmission V-belt, wherein the shape-retaining rubber layer has a storage elastic modulus in a belt length direction at a temperature of 1
00 ° C, static load 0.29MPa, dynamic strain 1%, frequency 10
Hz, 85% at 60MPa or more under tension mode conditions
MPa or less, compressibility 10%, temperature 120 ° C
A high load transmission V-belt, wherein the compression set after 24 hours is 60% or less under the following conditions: 2. The shape-retaining rubber layer is made of a hydrogenated nitrile rubber reinforced with a metal salt monomer, and has a Mooney viscosity of 120 ML1 + 4 (10
The high-load transmission V-belt according to claim 1, wherein the temperature is not less than 0 ° C) and not more than 200ML1 + 4 (100 ° C). 3. The shape-retaining rubber layer is composed of a hydrogenated nitrile rubber reinforced with a metal salt monomer, and is composed of a rubber composition containing the metal salt monomer in a ratio of 20% by mass or more and 35% by mass or less. The high load transmission V-belt according to claim 1 or 2, wherein 4. The V-belt for high load transmission according to claim 2, wherein the metal salt monomer is zinc acrylate or zinc methacrylate. 5. The shape-retaining rubber layer is reinforced by at least one filler selected from the group consisting of carbon black, silica, and calcium carbonate / talc. The high-load transmission V-belt according to any one of the preceding claims. 6. The shape-retaining rubber layer contains zinc oxide in an amount of 20 to 40 parts by mass per 100 parts by mass of the hydrogenated nitrile rubber reinforced with a metal salt monomer. The high-load transmission V-belt according to any one of claims 2 to 5.