JPH0710116Y2 - V belt for high load transmission - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a high-load transmission V-belt used in automobiles, agricultural machines, general industrial machines, and the like, and a pair of endless tension bands and the tension bands. Relates to a V-belt including a plurality of blocks locked in the belt longitudinal direction.

(Prior Art) Currently, a gear type or hydraulic type transmission is used as a transmission such as an automobile, a combine, and a tractor.
Belt type continuously variable transmissions are being developed for the purpose of improving operability and fuel efficiency.

The belt used in this belt type continuously variable transmission requires an extremely high torque transmission capability, and the conventional rubber V-belt cannot withstand a high lateral pressure and causes buckling deformation and cannot be used.

Therefore, various types of high-load transmission belts have been proposed in the past (for example, JP-A-46-4861 and JP-A-55-27).
595, JP-A-56-76745, JP-A-59-77147
(See Japanese Patent Publication).

In addition, the applicant also proposed a V-belt 104 constituted by engaging a plurality of blocks 103 with a pair of endless tension bands 101 and 102 by engaging a concave portion and a convex portion, as shown in FIG. (JP-A-60-49151, JP-A-62-151646)
(See the official gazette).

(Problems to be Solved by the Invention) In such a V-belt 104, the engaging protrusions of the block 103 are formed in the cog valleys of the tension bodies 101, 102, and the block 103 is formed by the elasticity of the elastomer forming the tension bodies 101, 102. It is designed to be retained, but as shown in FIG.
A force P ₁ that pushes the block 103 into the pulley 105 is generated when the pulley 105 enters the pulley 105 and is engaged with the pulley 105 due to the tension generated in the V-belt 100. A pulling force P ₂ is generated. Both of these forces P ₁ and P ₂ become a force for compressing the elastomer, and particularly in high load transmission, the elastomer undergoes permanent compression deformation. When the elastomer is permanently deformed, a gap is generated between the block 103 and the cog troughs 101a and 102a of the tension members 101 and 102, slip heat generation at this interface becomes large, and the elastomer deteriorates early and cracks. This will shorten the service life.

Further, as shown in FIG. 8, a shearing force F is generated in the longitudinal direction of the belt in the block 103 for transmitting power. This shearing force F is applied to the upper and lower cog crests 101b, 102b, 101 of the tension bodies 101, 102.
This causes strain in c and 102c and causes cracks A and B to occur.

The magnitude of the strain is determined by the shear spring constant of the tension bodies 101 and 102.

That is, in the belt 100 having the conventional block 103,
The engaging portion of the tension body 101, 102 with the block 103 is in contact with the elastomer, not the core body, and the elastomer has a low Young's modulus and the strain generated in the tension bands 101, 102 is large, so if the strain increases, In addition to heat generation, it also causes cracks and permanent deformation of the elastomer, causing the belt 10
When 0 is wound around the pulley 105, the fixing force of the block 103 is reduced, and slip heat is generated at the interface between the block 103 and the tension bands 101 and 102, which causes a reduction in belt life.

Therefore, it is conceivable to install a wool cloth of nylon and polyester on the upper and lower surfaces of the tension members 101 and 102 to prevent cracks, but such a wool cloth is heated in the manufacturing process and disturbs the orientation. As a result, the strength is lowered, and particularly in the transmission under high load and high rotation, a high load of repeated compression and extension acts on the tooth root, and the tooth root is cracked due to shearing force and damaged.

The present invention has been made in view of the above points, and an object of the present invention is to provide a high load transmission V-belt that prevents the block from swinging when the speed change pulley is engaged.

(Means for Solving the Problems) In the invention of claim (1), a cog in which a cog crest portion and a cog trough portion are alternately arranged is formed on the upper and lower surfaces, respectively, and a core is spiraled in the elastomer. A pair of endless tension bands that are embedded in a shape, and inclined surfaces that frictionally engage with the pulley groove surfaces of the pulleys on both sides, and are fitted into the tension bands that are open to the inclined surfaces. A plurality of blocks each having a groove formed therein, and engaging projections formed on the upper and lower surfaces of the fitting groove to engage with the cog valleys of the upper and lower surfaces of the tension band, respectively. Is a V-belt for high load transmission, in which the block is locked in the belt in the longitudinal direction of the belt by engagement with the locking projections of each block and is detachable in the belt width direction. In the lower cog valley, the canvas layers are directly stacked on the core body. It is something.

In the invention of claim (2), the canvas of the canvas layer is covered with a thin elastomer layer.

In the invention of claim (3), the core of the tension band is covered with a thin elastomer layer.

In the invention of claim (4), the canvas is a core yarn canvas of aromatic polyamide fiber.

(Operation) According to the invention of claim (1), the above-mentioned compressive forces P ₁ and P ₂ generated in the tension body when engaged with the pulley are directly passed through the canvas layer having a high Young's modulus to the core body. Can be accepted by. Therefore, in high load transmission, the cog valley of the cog of the tension body is not permanently deformed, and the sliding heat generation at the interface between the block and the cog valley of the tension body does not increase. In addition, as for the strain of the tension body due to the shearing force F, since the elastomer does not exist in the engaging portion with the block, the cog crest portion is adjacent to the core body having a high Young's modulus and the distance from the core body to the cog crest portion is increased. Since it can be shortened, the distortion becomes extremely small. For this reason, the fixing force of the block increases, and further, the cog crest portion of the tension body does not undergo permanent deformation during high load transmission, so that the fixing force of the block does not decrease.

According to the inventions of claims (2) and (3), in each tension band, the elastomer layer allows the fibers of the core body and the canvas layer to directly contact and rub against each other at the cog valley of the cog. Avoided.

According to the invention of claim (4), the elasticity of the tension body is increased by the characteristics of the fibers forming the core yarn, and the heat resistance and the resistance which are the defects of the core yarn due to the fibers forming the covering yarn. Wear resistance is prevented from decreasing.

Embodiment An embodiment of the present invention will be described in detail below with reference to the drawings.

As shown in FIGS. 1 to 3, 1 is a V-belt, which is a pair of endless tension bands 2 and 3 and which are locked to the tension bands 2 and 3 in their longitudinal direction and in the belt width direction. It is composed of a plurality of removable blocks 4, 4, ....

The tension bands 2 and 3 are formed by embedding core bodies 10 and 10 in a spiral shape in elastomers 9 and 9. Cogs 11,1 are provided on the upper and lower surfaces of the tension band 2.
2, the cogs 13 and 14 are formed on the upper and lower surfaces of the tension band 3, and the cogs 11, 12, 13 and 14 are the cog peaks 11a, 12a, 13a and 14a and the cog troughs 11b, 12b and 13b, respectively. 14b are alternately arranged.

On the other hand, the block 4 has side surfaces 4a and 4b on both sides as inclined surfaces that frictionally engage with the pulley groove surface of the pulley.
Fitting grooves 5 and 6 that open to a and 4b are formed respectively, and locking projections (only the locking projections 7a and 7b for the fitting groove 6 are provided on the front and rear portions on the upper surfaces of the fitting grooves 5 and 6). (Shown) respectively,
On the lower surface of the groove, a locking convex portion (only the locking convex portion 8 for the fitting groove 6 is shown) is provided in the central portion.

Then, while the engaging projections on the groove upper surfaces of the fitting grooves 5 and 6 of the block 4 mesh with the front and rear portions of the cog troughs 11b and 13b of the cogs 11 and 13 of the tension bands 2 and 3, respectively. The engaging projections on the groove lower surfaces of the fitting grooves 5 and 6 of the block 4 are engaged with the cog troughs 12b and 14b of the cogs 12 and 14, respectively. As a result, each block 4 is locked and fixed to the tension bands 2 and 3 in the longitudinal direction of the belt in a concave-convex engagement relationship, and is removable in the belt width direction.

Further, the tension bands 2 and 3 are the cog troughs 11 of the cogs 11, 12, 13, and 14.
No elastomer is present at the b, 12b, 13b, and 14b portions, and the canvas layers 15, 15, 16, and 16 are directly stacked above and below the core bodies 10 and 10, respectively.

Further, a support portion (fitting groove 6) for supporting the cog crest portions 12a and 14a of the cogs 12 and 14 of the tension bodies 2 and 3 is provided on both sides of the engaging convex portion on the lower surface of the fitting grooves 5 and 6 of the block 4, respectively. Is formed).

The upper surface of the locking convex portion on the lower surface of the groove of the block 4 is a curved convex surface having a radius of curvature close to the minimum pulley radius of the transmission pulley used in order to prevent bending fatigue of the core body 10.

On the other hand, the supporting portions 17 and 18 are formed to have a curved surface shape having a predetermined radius of curvature in the direction in which the cog crest portions 12a and 14a of the cogs 12 and 14 of the tension bodies 2 and 3 are pushed up. The center of this radius of curvature is located on the center line between the blocks 4 and 4, and the curved surface shape is such that when the V-belt 1 is wound around a pulley, the V-belt 1 is wound around a polygon and the core body 10 is This is to prevent it from becoming a polygon.

In each of the above tension bands 2 and 3, the core body 10 and the canvas layer 15 and 15
6,16 fibers and cogs 11,12,13,14 cog valleys 11b, 12b, 1
In 3b, 14b, a thin elastomer layer (not shown) may be provided between the core body 10, 10 and the canvas layers 15, 15, 16, 16 for the purpose of avoiding direct contact and rubbing. Good.
This elastomer layer can be formed, for example, by coating the surface of the canvas used for the canvas layers 15, 15, 16, 16 with an elastomer or by coating the core body 10 with a thin elastomer. The elastomer (e.g., rubber) of this elastomer layer has a smaller modulus and is softer than the elastomer forming the tension bands 2 and 3, so that the problem of deformation does not occur. The thickness of the elastomer layer is about 0.2 mm.

Further, as the canvas forming the canvas layers 15 and 16, in order to improve durability, a core yarn canvas whose warp and weft are made of aromatic polyamide fiber is used. As shown in FIG. 5, a core yarn canvas is formed by forming a warp yarn 20 of a canvas with a core yarn 21 made of unstretched synthetic fiber and a covering yarn 22 wound around the core yarn 21. is there.

In particular, since the core yarn canvas is used, in a canvas made of a normal aromatic polyamide fiber, when it is molded along the cogs of the tension bands 2 and 3, the elongation is small, so the cog shape is not accurately molded, and This is because the workability is poor, and the flexibility is improved by using the core yarn canvas, and the occurrence of cracks due to the shearing force at the cog valley is prevented. Further, the core yarn 21 is made of an elastic yarn and the covering yarn 22 is made of an aromatic polyamide fiber, so that the elasticity of the canvas is improved, the decrease in strength is reduced, and cracks are prevented. For the core yarn 21, for example, a urethane yarn having a large elongation is used as an elastic yarn,
Since urethane does not have good heat resistance and wear resistance, heat resistance,
Aromatic polyamide fiber with good abrasion resistance Covering yarn 22
Since the aromatic polyamide fiber does not have a large elongation, it is stretched by winding it in a spiral shape.

Further, the cog crests 11a and 13a of the tension bands 2 and 3 which engage with the central locking recess 7c located between the front and rear locking projections 7a and 7b on the upper surfaces of the fitting grooves 5 and 6 of the block 4. Is formed to have a semicircular cross section, and the center of its radius of curvature is located on the center line of the block 4 in the thickness direction.

In addition, the block 4 is the upper beam portion 4c of the block 4.
A lower beam portion 4d and a center pillar portion 4e connecting them at their central portions, and a reinforcing member is embedded inside if necessary.

With the above configuration, when the pulley is engaged,
The above-mentioned compressive forces P ₁ and P ₂ generated in the tension bodies 2 and 3 are directly received by the core bodies 10 and 10 via the canvas layers 15 and 16 having a high Young's modulus. Therefore, in high load transmission, the cogs 1 of the tension members 2 and 3
The cog troughs 11b, 12b, 13b, 14b of 1, 12, 13, 14 are not permanently deformed, and the cog troughs 11b, 1 of the block 4 and the tension bodies 2, 3 are not deformed.
Slip heat generation at the interfaces with 2b, 13b, and 14b does not increase.
Further, as for the strain of the tension bodies 2 and 3 due to the shearing force F, since the elastomer does not exist at the engaging portion with the block 4, the cog crest portions 11a, 12a, 13a and 14a have a high Young's modulus core body 10, Since the distance from the core body 10, 10 to the cog crests 11a, 12a, 13a, 14a adjacent to 10 can be shortened, the shear spring constant increases and the strain becomes extremely small. For this reason, the fixing force of the block 4 is increased, and the cog crest portion 11 of the tension bodies 2 and 3 is transmitted during high load transmission.
Since a, 12a, 13a and 14a do not undergo permanent deformation, the fixing force of the block 4 does not decrease.

Here, since the distances from the core bodies 10, 10 to the cog crests 11a, 12a, 13a, 14a can be shortened, the reason why the strain becomes extremely small is as follows.

Since the Young's modulus of the core body 10 is extremely larger than that of the elastomer, the core body portion is considered to be a substantially rigid body. Therefore, the distances from the core body 10 to the tips of the cog peaks 11a, 12a, 13a, 14a are l ₁ , l ₂
Considering (<l ₁ ), when the shearing force F acts,
Moments at points P ₁ and P ₂ near the body 10 are M ₁ = Fl ₁ and M ₂ = F
At l ₂ , M ₁ > M ₂ .

Therefore, when the same shearing force F acts, the shorter the distance from the core body 10 to the tips of the cog crests 11a, 12a, 13a, 14a, the smaller the moment acting and the smaller the amount of deformation. The fixing force of the block 4 is increased and deformation can be prevented.

In this way, the block 4 and the cog troughs 11 of the tension bodies 2 and 3 are
At the interface with b, 12b, 13b, 14b, the sliding heat does not increase, and the strain on the cog crests 11a, 12a, 13a, 14a is reduced, and cracks due to shearing force can also be prevented, so durability is greatly improved. Improve to.

In particular, canvas layers 15, 15, 16, 16 installed on the upper and lower surfaces of the tension bodies 2, 3,
Since the warp yarns 20 arranged in the belt longitudinal direction are formed by the core yarn 21 made of unstretched synthetic fiber and the covering yarn 21 wound around the core yarn 21,
Due to the characteristics of the fibers forming the core yarn 21, the tension members 2, 3
The elastic modulus can be increased, and the fibers constituting the covering yarn 22 can prevent deterioration of heat resistance and abrasion resistance, which are the drawbacks of the core yarn 21.

Therefore, even if the V-belt 1 is used for a long period of time, it is possible to improve the durability without causing shear cracks in the cog valley portion and lowering the strength. Moreover, since the core yarn 21 is covered by wrapping the covering yarn 22, the stretching effect (enhancing the elastic modulus of the tension bodies 2 and 3) without hindering the stretching operation of the core yarn during belt molding.
Is fully demonstrated.

(Effect of the Invention) In the invention of claim (1), when the pulley is engaged, the compressive force generated in the tension body is directly received by the core body through the canvas layer having a high Young's modulus. During transmission, permanent deformation does not occur in the cog valley of the cog of the tension body, the sliding heat generation at the interface between the block and the cog valley of the tension body does not increase, and the strain of the tension body due to shearing force is Since the elastomer does not exist in the engaging portion with the block, the cog crest portion is adjacent to the core body having a high Young's modulus, and the distance from the core body to the cog crest portion can be shortened, resulting in extremely small strain. Therefore, the fixing force of the block increases, and further, the cog crest portion of the tension body does not undergo permanent deformation during high load transmission, so that the fixing force of the block does not decrease.

According to the inventions of claims (2) and (3), in each tension band, the elastomer layer prevents the fibers of the core body and the fabric layer from directly contacting and rubbing at the cog valley of the cog. .

According to the invention of claim (4), the elasticity of the tension body is increased due to the characteristics of the fibers constituting the core yarn, and the fibers constituting the covering yarn have heat resistance and abrasion resistance which are defects of the core yarn. The drop is prevented.

[Brief description of drawings]

1 to 5 show an embodiment of the present invention, FIG. 1 is a perspective view of a V-belt for high load transmission of the present invention, FIG. 2 is a longitudinal sectional view thereof, and FIG. 3 is a side view thereof. FIG. 4 is a perspective view of the warp yarns of the core yarn canvas, and FIG. 5 is an operation explanatory view. 6 to 8 show a conventional example, FIG. 6 is a perspective view of a conventional V belt, and FIGS. 7 and 8 are explanatory views of the operation. 1 …… V-belt 2,3 …… Tension band 4 …… Block 4a, 4b …… Side (slope) 5,6 …… Mating groove 8 …… Locking protrusion 11,12,13,14 …… Cog 11a, 12a, 13a, 14a …… Cog mountain part 11b, 12b, 13b, 14b …… Cog valley part 15, 16 …… canvas layer

Claims (4)

[Scope of utility model registration request] 1. A pair of endless tension bands in which a cog is formed by alternately arranging a cog crest portion and a cog trough portion on upper and lower surfaces, and a core is spirally embedded in an elastomer. And a slanting surface on both sides that is frictionally engaged with the pulley groove surface of the pulley, and a fitting groove that is opened in the slanting surface and is fitted to the tension band is formed. A plurality of blocks in which locking projections that engage with the cog valleys of the upper and lower surfaces of the tension band are formed, and by engaging the cog valleys of the tension band with the locking projections of each block, A V-belt for high load transmission, wherein a block is locked in the belt longitudinal direction with respect to the tension band and is detachable in the belt width direction, and is directly attached to the core body at the cog valleys of the upper and lower surfaces of the tension band. A V-belt for high-load transmission, which is characterized by stacking canvas layers. 2. The V for high load transmission according to claim 1, wherein the canvas of the canvas layer is covered with a thin elastomer layer.
belt. 3. The V-belt for high load transmission according to claim 1, wherein the core of the tension band is covered with a thin elastomer layer. 4. The V-belt for high load transmission according to claim 1, wherein the canvas is a core yarn canvas of aromatic polyamide fiber.