JP2003004103A - High load transmission belt - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the reverse bending of a belt by limiting the thicknesses of blocks, to relieve center belts from burden and provide a longer service life by reducing vibration between spans of a pulley and to improve transmission efficiency by stabilizing the entry of the belt into the pulley. SOLUTION: This high load transmission belt 1 comprises center belts 3a, 3b having cores 5 embedded therein and the plurality of blocks 2 provided on the center belts. A T/P value is within 0.983-1.027 where T is the thickness of the block and P is the pitch of the block.

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 belt in which blocks are fixed at a predetermined pitch along the longitudinal direction of a center belt, and more specifically, a high load transmission belt which prevents the reverse bending phenomenon during traveling is provided. Regarding load transmission belt.

[0002]

2. Description of the Related Art A belt used in a belt type continuously variable transmission is used by being wound around a variable speed pulley in which the effective groove diameter of the pulley is changed by changing the V groove width of the pulley to adjust the gear ratio. However, since the lateral pressure from the pulley increases, the belt must withstand the large lateral pressure. In addition to the use of continuously variable transmission, it is necessary to use a belt that can withstand a particularly high load in a high load transmission application in which a normal rubber belt has a too short life.

Among such belts used is a high-load transmission belt in which a block is fixed to a center belt to increase the strength in the belt width direction. As a concrete structure, a core is made of rubber or the like. And a block made of an elastomer that is relatively harder than the elastomer used for the center belt is fixed to a center belt embedded in the elastomer of FIG. -34342, there is a belt having grooves on both side surfaces of a block and having a pair of center belts fitted in the grooves provided on the side surfaces.

As the required quality of such a tension transmission type high load transmission belt, it is used for continuously variable transmission as described above. In the continuously variable transmission, the speed is changed by changing the effective diameter of the pulley around which the belt is wound, and the belt is used with a small pulley diameter.

Particularly when the belt is wound around a small pulley diameter, the inner peripheral surface of the center belt is sandwiched between blocks and stress is concentrated, and the rubber constituting the center belt deteriorates and cracks occur. , It caused the belt to be cut.

Therefore, in order to reduce the concentration of stress applied to such a center belt, Japanese Patent Laid-Open No. 62-151646 has been proposed.
Is set so that the upper end of the convex part provided on the inner peripheral surface of the center belt is located above the lower end position of the convex part of the block, and when the belt is wound around the pulley and bent, the convex part of the center belt A belt has been proposed so that it will not be pinched by blocks.

Further, in Japanese Unexamined Patent Publication No. 9-25999, the radius of curvature of the convex portion formed by the block is set to be smaller than the radius of curvature of the concave portion formed on the inner peripheral surface of the center belt in the portion where the block and the center belt are fitted together. A belt in which a gap is provided between the two is disclosed.

[0008]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention JP-A-62-15
By adopting a configuration such as 1646 or Japanese Patent Application Laid-Open No. 9-25999, stress is concentrated on the inner peripheral surface of the center belt due to the bending of the belt, cracks are generated in the center belt, and heat is generated to cause a material such as rubber. It is possible to mitigate the occurrence of problems such as deterioration of the.

However, another cause is that the belt shakes between the spans of the pulleys around which the belt is wound. The runout of the belt imposes an excessive load on the center belt and shortens the life of the belt. Not only that, but there is also a problem that the runout of the belt affects the penetration of the belt into the pulley, resulting in a reduction in transmission efficiency.

Such a problem is caused by the above-mentioned JP-A-62-15.
With the configuration such as 1646 or Japanese Patent Laid-Open No. 9-25999, the problem cannot be solved, and further research has been awaited.

Therefore, the present invention solves the above problems and reduces the amount of belt runout occurring between the spans of at least a pair of pulleys to prevent the center belt from being fatigued and to prevent the belt from moving to the pulleys. The purpose of the present invention is to provide a high load transmission belt with high transmission efficiency by smoothing intrusion.

[0012]

In order to achieve the above object, in claim 1 of the present invention, a center belt having a core body embedded in an elastomer, and a predetermined pitch along the longitudinal direction of the center belt. In a high load transmission belt composed of a plurality of blocks provided in, when the block thickness is T and the block pitch is P, the value of T / P is in the range of 0.983 to 1.027. Is characterized by.

By setting the block thickness and the block pitch within the predetermined ranges as described above, the reverse bending of the belt is prevented by the restriction of the block thickness, and the runout between the spans of the pulleys is prevented. Less. As a result, the load on the center belt is reduced, the life of the belt is extended, and the intrusion of the belt into the pulley is stabilized, so that the transmission efficiency can be improved.

According to a second aspect of the present invention, the block is composed of an upper beam, a lower beam, and a pillar connecting the both, and has a groove for fitting a center belt surrounded by the upper beam, the lower beam, and the pillar. The block thickness T is a thickness of the belt traveling method in the upper beam, and is a high load transmission belt in which an inclined surface for bending the belt is provided on at least one of front and rear surfaces in the belt traveling direction in the lower beam. .

The lower beam is provided with an inclined surface so that the belt can be bent when it is wound around the pulley, and the thickness of the upper beam is set to have a thickness-pitch relationship as in claim 1. Thus, it is possible to prevent the runout due to the reverse bending of the belt between the spans of the pulleys.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be specifically described below with reference to the drawings.

FIG. 1 shows a high load transmission belt 1 according to the present invention.
FIG. 2 is a schematic perspective view showing an example, and FIG. 2 is a side sectional view thereof. The high load transmission belt 1 of the present invention is made of an elastomer 4
Two center belts 3a and 3b having the same width in which a rope-shaped core body 5 is embedded in a spiral shape, and recessed lines formed at a predetermined pitch on the upper and lower surfaces 6 and 7 of the center belts 3a and 3b. It is composed of a plurality of blocks 2 which are fitted to the portions 18 and 19 and are fixedly locked. Both side surfaces 2a, 2b of the block 2 are inclined surfaces that engage with the V groove of the pulley, and receive the power from the driven pulley to lock and fix the center belt 3a,
By pulling 3b, the power of the driving pulley is transmitted to the driven pulley.

As shown in FIG. 1, the block 2 includes an upper beam portion 11 and a lower beam portion 12, and an upper and lower beam portions 11,
The center pillars 13 are formed by connecting the central portions of the blocks 12 to each other.
Grooves 14 and 15 into which a and 3b are fitted are formed. Further, on the groove upper surface 16 and the groove lower surface 17 in the groove 15, the ridge portions 20 and 21 that engage with the groove portions 18 provided on the upper surface 6 and the groove portions 19 provided on the lower surface 7 of the center belts 3a and 3b. Is provided.

FIG. 3 shows an example of another belt, which is a pair of side pillars 3 which are directed upward from both ends of the beam portion 31.
2, 33 extend, and lock portions 34, 35 extending from the upper ends of the side pillars 32, 33 toward the center of the block 2 are provided so as to face each other. Then, the center belts 3a and 3a, 3a, 3a
A fitting groove 30 into which b is fitted is formed. In the fitting groove 30, the center belts 3a and 3b are locked by the lock portions 34,
It is inserted from the opening between 35 and mounted. Further, convex portions 37 are provided on the fitting grooves 30 side of the lock portions 34 and 35, respectively.
It is fitted in the recesses 36 provided at a predetermined pitch in a and 3b. As a result, the center belts 3a and 3b are in a state of being difficult to come off from the block 2 after being worn.

This block 2 is made only of synthetic resin material, and no insert material made of metal such as aluminum alloy is buried. However, the insert material made of metal or the like here refers to a skeleton that is almost in the shape of a block by itself, for example, a reinforcing material such as short fibers or whiskers added in a form mixed in a synthetic resin material. Adding does not mean embedding the insert material.

In the case of the belt using the block in which the insert material is not embedded, the belt can be made lighter than the belt using the block in which the insert material is embedded, so that the belt is generated even when used at high speed. Although it has the advantage of low centrifugal force, it is inferior in lateral pressure resistance,
It will be used with a relatively light load such as motorcycles.
In such applications, the gear ratio is important, and it is often used with a fairly small pulley diameter in order to widen the range of gear shifting. When the belt is wound around a small pulley diameter, the center belt is burdened when the belt is bent, and deterioration of the center belt due to stress becomes a problem.

In the present invention, in such a high load transmission belt, when the block thickness is T and the block pitch is P as shown in FIG. 2, the value of T / P is 0.983 to.
It is within the range of 1.027. Here, the thickness of the block means the thickness of the block substantially on the outer peripheral side of the belt. In order to prevent the reverse bending of the belt, it is necessary that the block is restricted on the outer periphery of the belt to prevent the reverse bending. However, it is not strictly the outermost thickness of the belt, for example,
If the above T / P value in the thickness of the upper beam satisfies the above range, chamfering or R
Even if it is processed, it is possible to prevent the belt from being bent backward. In short, on the outer peripheral side of the position where the core body of the center belt, which is the center of bending of the belt, is embedded,
The thickness of the block satisfying the relationship between the thickness and the pitch described above, and if the reverse bending of the belt can be prevented, the object of the present invention such as reducing the runout of the belt can be achieved. It can be said to be included in the invention.

If the value of T / P is less than 0.983, the belt reverse bending becomes large, leading to bending fatigue of the center belt and reduction in transmission efficiency. If it exceeds 1.027, the buffer between the blocks will increase during running of the belt, which may cause wear of the blocks, generation of noise, heat generation, etc., so that the life of the belt may be shortened or the flexibility may be impaired. It is also not preferable.

On the other hand, the lower beam of the block must be allowed to bend so that the belt can be wound around the pulley, and an inclined surface is provided on at least one of the front and rear surfaces in the belt running direction. By providing the inclined surface, the belt can be bent without buffering the blocks. On the contrary, since the upper beam has a thickness, the blocks buffer each other so that the belt cannot be reverse-bent. When the reverse bending is thus prevented, the belt does not swing between the spans of the pulleys, the fatigue of the center belt is reduced, and the life of the belt is extended. Further, when the belt runout is eliminated, the belt can smoothly enter the pulley, so that the transmission efficiency can be improved.

What is used as the elastomer 4 of the center belts 3a, 3b is a single material such as chloroprene rubber, natural rubber, nitrile rubber, styrene-butadiene rubber or hydrogenated nitrile rubber, or a rubber or polyurethane in which these are appropriately blended. Examples thereof include rubber. As the core body 5, a rope selected from polyester fiber, polyamide fiber, aramid fiber, glass fiber, steel wire and the like is used. Further, as the core body 5, other than the one in which a rope is embedded in a spiral shape, a woven cloth, a knitted cloth, a metal thin plate or the like of the above fibers can be used.

Polyamide resin, polyamideimide (PAI) resin, polyphenylene sulfide (PPS) resin, polybutylene terephthalate (PBT) resin, polyimide (P) can be used as the block resin.
Synthetic resins such as I) resin, polyether sulfone (PES) resin, and polyether ether ketone (PEEK) resin are used. Among them, they have a low friction coefficient, excellent wear resistance, rigidity and elasticity against bending. It is preferable to use a resin that has properties and is not easily broken, and a polyamide resin, particularly nylon 46 is preferable.

In the present invention, it is possible to mix a fibrous reinforcing material or a whisker-like reinforcing material in the synthetic resin forming the block as described above, and the fibrous reinforcing material is 15 to 4
It is compounded in the range of 0% by weight. If it is less than 15% by weight, there is a problem that the reinforcing effect is small and the abrasion resistance of the block is not sufficient, and if it exceeds 40% by weight, it becomes difficult to mix it with the resin or injection molding becomes difficult. It is not preferable because there is a problem of.

Examples of the fibrous reinforcing material to be added to the synthetic resin include aramid fiber, carbon fiber, glass fiber, polyamide fiber, polyester fiber and the like. Among them, by using nylon 46, which is a preferable example of the resin forming the block, and carbon fiber in combination, the carbon fiber can improve the water absorption defect of nylon 46 and significantly improve the rigidity, In addition, the wear resistance, impact resistance, and fatigue resistance of nylon 46 can be fully utilized. Among the carbon fibers, it is preferable to use PAN-based carbon fibers. Further, by blending the aramid fiber in combination with the carbon fiber, the toughness of the block is improved, and the wear resistance and the impact resistance can be further improved.

The PAN-based carbon fiber used here is
It has good compatibility with thermoplastic resin and the length of carbon fiber used is 1
It is preferably about 5 mm. If it is less than 1 mm, the block will not be sufficiently reinforced, and if it exceeds 5 mm, it will be difficult to knead with the resin, and it will be broken and shortened during kneading, which is not preferable.

In addition to the above organic fibers, inorganic fibers such as zinc oxide whiskers, potassium titanate whiskers and aluminum borate whiskers may be blended as the fibrous reinforcing material. Of these, zinc oxide whiskers are preferably used. Zinc oxide whiskers have a three-dimensional shape with hands extending in four directions in a tetrapot shape. This zinc oxide whisker alone has excellent heat resistance and abrasion resistance, but since it has a tetrapod-like three-dimensional shape as described above, when it is blended with carbon fiber, the orientation of carbon fiber Is suppressed, and the anisotropy of warpage and molding shrinkage during molding is improved. Further, since the orientation of the carbon fibers can be reduced in this way, the anisotropy of strength such as toughness and bending rigidity of the block 2 can be reduced, and the friction coefficient is stable, so that the wear resistance is improved. To do.

Further, since the zinc oxide whisker has a high specific gravity and a high rigidity, it is possible to reduce vibration at the time of contact with the pulley and to reduce noise generation. When the amount of this zinc oxide whisker is small, the effect of addition is not exhibited, and when it is too large, kneading cannot be performed and molding becomes difficult.

By adopting such a material constitution,
It has strength such as rigidity and toughness that can withstand the lateral pressure that it receives when it comes into contact with the pulley, and it has excellent wear resistance.
Furthermore, it becomes possible to form a block that is strong against heat generated during friction, and the power received from the pulleys can be efficiently transmitted to the center belts 3a and 3b as a tensile force, and a tension transmission type high load transmission belt. Can be configured.

In addition to these, molybdenum disulfide,
The lubricity of the block 2 can also be improved by mixing at least one selected from graphite and fluorine resin. Examples of the fluorine-based resin include polytetrafluoroethylene (PTFE), polyfluoroethylene propylene ether (PFPE), tetrafluoroethylene hexafluoropropylene copolymer (PFEP), polyfluoroalkoxyethylene (PFA), and the like. .

The block used in the high load transmission belt according to the present invention is not limited to the form shown in this embodiment.

[0035]

[Examples] Next, high-load transmission belts having different block thicknesses were produced, running tests were performed using the respective belts, and the magnitude of the belt runout was compared.

(Example 1) The high load transmission belt used was a block as shown in FIG. 1, and as the material of the block, 100 parts by weight of nylon 46 was mixed with 30 parts by weight of carbon fiber. What was done was used. In addition, hydrogenated nitrile rubber was used as the elastomer for the center belt, and a rope made of aramid fiber was embedded in the elastomer in a spiral shape as the core body. The block pitch P is 3 mm and the block thickness T is 3.05.
And Details of the shape and size of the belt are shown in Table 1.

An actual machine equipped with the obtained belt (250
cc scooter) was installed on the chassis dynamo, and a full throttle was applied for a maximum load of 280 seconds to run for 430 seconds. The runout of the belt on the tension side and the slack side was measured at the time of acceleration and at the steady state, with the acceleration until reaching the maximum speed and the steady state after reaching the maximum speed. The results are shown in Table 2.

(Example 2) The block thickness is 3.00 m.
Exactly the same belt as in Example 1 was prepared except that the length was changed to m. Details of the shape and size of the belt are shown in Table 1.

Using the obtained belt, the runout of the belt on the tension side and the belt on the slack side at the time of acceleration and at the time of steady state were measured in the same manner as in Example 1. The results are shown in Table 3.

(Comparative Example 1) The thickness of the block was 3.10 m.
Exactly the same belt as in Example 1 was prepared except that the length was changed to m. Details of the shape and size of the belt are shown in Table 1.

Using the belt thus obtained, the runout of the belt on the tension side and the belt on the slack side during acceleration and in the steady state was measured in the same manner as in Example 1. The results are shown in Table 3.

(Comparative Example 2) The block thickness is 2.90 m.
Exactly the same belt as in Example 1 was prepared except that the length was changed to m. Details of the shape and size of the belt are shown in Table 1.

Using the obtained belt, the runout of the belt on the tension side and the belt on the slack side during the steady state and during the acceleration were measured in the same manner as in Example 1. The results are shown in Table 3.

[0044]

[Table 1]

[0045]

[Table 2]

As can be seen from the results shown in Table 2, the belt of the example has less belt runout than the belt of the comparative example 2 during acceleration and in a steady state, and the center belt is less fatigued and the service life is extended. Expected. Also,
Smooth entry into the pulley and higher transmission efficiency. Further, in Comparative Example 1, the flexibility was so poor that the running test could not be conducted.

[0047]

As described above, according to the first aspect of the present invention, the height of the center belt in which the core body is embedded in the elastomer and the plurality of blocks provided at a predetermined pitch along the longitudinal direction of the center belt. In the load transmission belt, when the block thickness is T and the block pitch is P, the value of T / P is in the range of 0.983 to 1.027.

By setting the block thickness and the block pitch within the predetermined ranges as described above, the reverse bending of the belt is prevented by the restriction of the block thickness, and the runout between the spans of the pulleys is prevented. Less. As a result, the load on the center belt is reduced, the life of the belt is extended, and the intrusion of the belt into the pulley is stabilized, so that the transmission efficiency can be improved.

According to a second aspect of the present invention, the block is a block having an upper beam, a lower beam and pillars connecting the both, and having a groove for fitting a center belt surrounded by the upper beam and the lower beam. The block thickness T is a thickness of the belt traveling method in the upper beam, and is a high load transmission belt in which an inclined surface for bending the belt is provided on at least one of front and rear surfaces in the belt traveling direction in the lower beam. .

The lower beam is provided with an inclined surface so that the belt can be bent when it is wound around the pulley, and the thickness of the upper beam is set to have a thickness-pitch relationship as in claim 1. Thus, it is possible to prevent the runout due to the reverse bending of the belt between the spans of the pulleys.

[Brief description of drawings]

FIG. 1 is a schematic perspective view showing an example of a high load transmission belt according to the present invention.

FIG. 2 is a side sectional view of a high load transmission belt.

FIG. 3 is a schematic perspective view showing another example of the high load transmission belt according to the present invention.

[Explanation of symbols]

1 High load transmission belt 2 blocks 3a Center belt 3b center belt 4 Elastomer 5 mind and body 6 upper surface 7 Lower surface 11 Upper beam section 12 Lower beam part 13 center pillars 14 Mating groove 15 Fitting groove T block thickness P block pitch

Claims (2)

[Claims] 1. A high load transmission belt comprising a center belt in which a core is embedded in an elastomer, and a plurality of blocks provided at a predetermined pitch along the longitudinal direction of the center belt. The value of T / P is 0.983 to 1.02, where P is the pitch of
A high load transmission belt characterized by being in the range of 7. 2. The block comprises an upper beam, a lower beam and pillars connecting the both, and the upper beam,
A block having a groove for fitting a center belt surrounded by a lower beam and pillars, the thickness T of the block is a thickness of a belt traveling method in the upper beam, and at least the front and rear surfaces in the belt traveling direction in the lower beam. The high load transmission belt according to claim 1, wherein an inclined surface for bending the belt is provided on one side.