JPH0232914Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a block belt for high-load power transmission in which a block is attached to a flat belt, and particularly to the shape of the fitting portion between the belt and the block.

(Prior art) Block belts are widely used for high-load transmission applications because they can adopt a structure with a small thickness-to-width ratio in response to changes in the desired speed ratio of variable-speed belt drive devices. , Japanese Patent Publication No. 1983-
Many inventions and ideas have been proposed, including Publication No. 79349.

By the way, there are generally two major characteristics required of this type of high-load transmission belt. One of these is that it has good flexibility, and the other is that it has sufficient rigidity to withstand the pressure applied to the side surface of the belt. However, these two characteristics are contradictory to each other, and if you try to improve one characteristic, the other characteristic ends up being diminished.

Therefore, as a means of dealing with the above-mentioned problems, attempts have been made to improve the rubber compounding technology, to use metal belts, to bolt V-shaped blocks, etc. However, there are certain limits to the improvement of rubber compounding technology, and metal belts are unfavorable in terms of weight and cost, so generally bolts are often used.

By the way, the transmission of load between two shafts is generally carried out on the drive side through a path of pulley -> block -> flat belt, while on the driven side, it is carried out through a path of flat belt -> block -> pulley.

Therefore, in a high-load power transmission belt in which a block is attached to a flat belt, the efficient power transmission between the block and the flat belt determines its transmission capability.

In this sense, bolt tightening in particular makes it possible to transmit power between two shafts by pulling the frictional force between the pulley and belt with the belt, so the block and belt are both strong. It becomes important that the agreement is concluded.

However, in bolt tightening as described above, if the block is simply fastened to the flat belt, the tension force of the belt due to the frictional force between the block and the pulley in the belt, and the tension between the pulley and the block. Due to the frictional force and shearing force between the belt and the belt, concentrated stress acts only on the bolt, causing the bolt to break or the bolt hole to tear, or the belt to break due to uneven distribution of tensile stress in the rope. The problem arises that the durability of the material is significantly impaired.

Therefore, the inventors of the present invention focused on this problem and first provided a concave or convex portion on the belt, and on the other hand,
It was proposed that the shearing force be uniformly distributed in the width direction of the belt by providing a block with a shape that fits into the concave or convex portion, and by fitting them together and fastening them with bolts, thereby eliminating the above-mentioned drawbacks. .

(Problem to be solved by the invention) However, when the blocks are fitted to the flat belt as described above, the shapes or radii of curvature of the uneven parts that fit together are usually made to be the same. As shown in Figure 3, on the driving side, a compressive force Q is applied between the concave side wall of the flat belt and the block in the forward direction of the block, and on the driven side, a compressive force P is applied on the rear side of the block. As a result, stress is concentrated at the front and rear bases of the convex portions of the flat belt (corner portions of the concave portions), causing shearing force between the flat belt and the block, which causes deterioration of this portion, and when the belt wraps around the pulley, the block is essentially damaged. The radius of curvature of the flat belt tends to increase, and extra compressive force is applied to the convex portion of the flat belt, resulting in transmission loss, heat generation and deterioration, and a problem that impairs the durability of the belt.

The present invention addresses this problem by focusing on the shape of the mating surface of the flat belt and the block, as well as the rounded portion and radius of curvature on both sides, to avoid concentration of stress, and to ensure smooth contact between the block and the flat belt during load transfer. The purpose is to apply compressive force to the belt, increase the transmission force, and improve the durability of the belt.

(Means for Solving the Problems) However, the features of the present invention for solving the above problems are shown in FIGS. 1 and 2, but basically, A tensile rope 3 is embedded in an elastic body 4, and a block 2 is fastened to the flat belt 1 at a required pitch at right angles along the longitudinal direction of the flat belt 1 with a fastening member 5 such as a bolt. This is a high-load transmission belt having a concave portion 1a and a fitting portion 2a that fit into each other on the fastening joint surface with the flat belt 1 and the block 2, and in particular, the flat belt 1 and the block 2 have a fitting uneven surface shape where the flat belt 1 and the block 2 are in contact with each other. The flat belt is formed with a central straight portion and rounded portions on both sides that fit into each other, and the length of the straight portions is equal, while the radius of curvature R ₁ of the rounded portions on both sides of the recessed portion of the flat belt is The reason is that the radius of curvature _R2 is made larger than or equal to the radius of curvature of the part.

(Function) In the high-load power transmission belt having the above-mentioned configuration, stress is distributed by the fitting of the blocks and the hooking force due to the uneven fitting of the blocks, and the stress concentration effect on the fixed part due to bolt tightening is achieved. As a result, bolt breakage and bolt hole tearing do not occur, and the tensile stress applied to the tensile rope becomes uniform in the belt width direction, preventing belt breakage and significantly extending belt life. Also, when the belt wraps around the pulley and transmits the load, if R ₁ < R ₂ , extra compressive force will be applied to the concave wall of the flat belt, but if R ₁ ≧ R ₂
Therefore, in effect, R ₁ = R ₂ ,
Compressive force will be applied smoothly.

In particular, during load transfer, shear forces are normally generated between the belt and the block;
In the above configuration, a force acts on the block to rotate it around point O of the rope line.

At this time, due to the presence of the straight part, the rotation of the block can be minimized by the pressure between the rope part and the block, and it is possible to avoid applying excessive force to the bolt. Improve durability.

Also, by providing the circular arc portions on both sides, the concentrated stress of the pressure Q applied between the block and the flat belt is avoided.

Moreover, although a gap is created between the two due to the difference in the radius of curvature, when the pulleys are fitted, the flat belt and the block pulley are in complete contact, and the tension applied to the tensile rope across the entire width of the belt is evenly shared, thereby transmitting force. Improve.

(Embodiments) Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

FIGS. 1 and 2 are side sectional views showing one example of the high-load transmission belt of the present invention.

In the figure, 1 is a flat belt constituting a high-load transmission belt, 2 is a block arranged on the flat belt, and the flat belt 1 is covered with a spiral tensile rope 3 and an elastic body 4 is disposed thereon. Although not shown, canvas is laminated and adhered to the lower surface or both upper and lower surfaces.

Here, the tensile rope 3 buried in parallel in a spiral shape is a low elongation, high strength rope selected from polyester, aliphatic polyamide, aromatic polyamide (trade name: Kevlar), glass fiber, wire, etc. The elastic body 4 covering the elastic body is made of NR (natural rubber), SBR (styrene-butadiene rubber), CR (chloroprene rubber),
It is made of a single material such as NBR (nitrile rubber), IIR (butyl rubber), Hypalon (chlorosulfonated polyethylene), or a rubber that is an appropriate blend of these materials, or a resin material such as polyurethane.

On the other hand, the block 2 is preferably made of a material with greater rigidity than the elastic body constituting the flat belt 1.
Specifically, hard rubber with a hardness of 85° or more, hard polyurethane, resins such as phenolic resin, epoxy resin, nylon resin, polyester resin, acrylic resin, methacrylic resin, or these resins, cotton thread, chemical fiber, glass fiber, etc. It is made of reinforced resin mixed with short fibers such as metal fibers, canvas impregnated with the resin, spirally or laminated and molded and hardened, or rubber coated, coated, or glued.

The block 2 is usually formed into an inverted trapezoidal shape with a linear plane, and is connected to the flat belt 1 by a fitting method in which the blocks 2 are fitted into each other. The fitting part 2a of the block 2 is fitted into the recess 1a, and the flat belt 1 is secured to the flat belt 1 with a required pitch in the longitudinal direction of the belt by means of fastening materials 5 such as bolts or rivets. The belt is fastened and fixed across the width of the belt.

It is also effective to make part of the upper and lower blocks at a wide angle or provide a gap to shorten the length of the block that contacts the pulley, thereby making it difficult for large forces to be applied to the block and preventing bolt breakage.

Further, the fitting shape of the two joining surfaces is not limited to the illustrated example, but can be modified as appropriate as long as the shapes fit together with each other, and this is included in the present invention.

FIG. 2 particularly shows the structure of the fitting part between the flat belt 1 and the block 2, which is the main part of the present invention, in the above structure.
The fitting surface 2a of the block 2 and the fitting surface of the block 2 are in contact with each other at a central straight portion and arcuate rounded portions at both ends thereof. In this case, when the radius of curvature of the rounded portions on both sides of the concave portion 1a of the flat belt is R ₁ , and the radius of curvature of the rounded portions on both sides of the block is R ₂ , there is a relationship of R ₁ ≧R ₂ .

Incidentally, although not particularly essential, the above R ₁ and R ₂ are 3
It is preferable that the relationship satisfies <R ₂ ≦R ₁ <50.

Thus, the high-load transmission belt as described above is used as a power transmission belt by being wrapped around a pulley in the same manner as a conventional belt, but at this time, the tension between the belt and the tension between the pulley and the block is The shearing force and compressive force with the frictional force become uniform in the belt width direction, and the tensile stress applied to the tensile rope becomes uniform, and stress concentration at the time of contact between the flat belt and the block is avoided, preventing bolt breakage and bolt hole tearing. There is no need to worry about bolt breakage caused by such problems, and there is no extra compressive force at the contact area between the two, so there is no transmission loss, and damage due to heat deterioration is prevented, achieving smooth power transmission over a long period of time.

(Effects of the invention) As described above, the present invention provides a high-load power transmission belt in which blocks are fastened and fixed at required pitches at right angles along the longitudinal direction of the flat belt by fastening materials. Since the fastening joint surfaces are shaped to fit into each other with a central straight portion and rounded portions on both sides, and the radius of curvature of the rounded portions on both sides at the fitting contact portion of both is varied, the above-mentioned fitting is improved. Therefore, when a load is transmitted in the width direction of the belt, a shearing force is generated between the belt and the block, and a force that tries to rotate the block around the rope line point is exerted on the block, but due to the straight line in the center of the two, the rope part and the block are The rotation of the block can be minimized by applying pressure, avoiding excessive force being applied to the bolt, and stress can be relieved by the hooking force of the block without applying concentrated stress to the bolt. By dispersing the stress, it eliminates bolt breakage and tearing of bolt holes, eliminates belt breakage caused by uneven tensile stress of the rope, greatly improves belt durability, and especially improves the fit between flat belts and blocks. By making both sides of the joining part rounded with a radius of curvature, it is possible to avoid the concentrated stress of the pressure applied to the joint part, which has a remarkable effect of preventing damage to the joint part.

Moreover, in the present invention, as mentioned above, the radius of curvature of the rounded part of the belt recess is made larger than that of the block, and a gap is provided between the two, thereby reducing the extra compressive force generated between the block and the flat belt recess wall surface. In addition to reducing transmission loss and eliminating transmission loss, when the pulleys are fitted, the fitting surfaces of the pulleys are in complete contact with each other in the pulleys, and the tension applied to the rope across the entire width of the belt is evenly shared, which also has the effect of improving the transmission force.

Thus, with the above configuration, the meshing between the blocks and the flat belt becomes smooth, and efficient power transmission between them is achieved, further doubling the performance of the belt as a high-load transmission belt.

[Brief explanation of the drawing]

Figure 1 is a partial side cross-sectional view showing the main parts of the high-load power transmission belt according to the present invention, Figure 2 is a partially enlarged view of Figure 1, and Figure 3 shows the high-load power transmission belt hung on a pulley. FIG. DESCRIPTION OF SYMBOLS 1... Flat belt, 2... Block, 3... Tensile rope, 4... Elastic body, 5... Fastening material, 1a...
...Recessed part of flat belt, 2a... Inserted part of block.

Claims (1)

[Scope of Claim for Utility Model Registration] 1. A high-load device made by fastening blocks with fastening materials such as bolts at required pitches in the perpendicular direction along the longitudinal direction of a flat belt in which a tensile rope is embedded in an elastic body. In the power transmission belt, the flat belt has irregularities at regular pitches perpendicular to the longitudinal direction of the belt, and the blocks are shaped to fit into the recesses of the flat belt, and the blocks are fitted into the recesses of the flat belt. At the same time, the mating surfaces of the flat belt and the block are formed with a central straight part and arcuate rounded parts on both sides, and the length of the straight parts is equal, and the flat belt is fastened with a fastening material. Block the radius of curvature R ₁ of the rounded parts on both sides of the concave radius of curvature R ₂ of the rounded parts on both sides of the recess
A high-load power transmission belt characterized by having R ₁ ≧ R ₂ . 2. Scope of claims for utility model registration in which the radius of curvature R ₁ of the curved portions on both sides of the concave portion and the radius of curvature R ₂ of the curved portions on both sides of the fitting side in the fitting of the flat belt and the block are in the relationship of 3 < R ₂ ≦ R ₁ < 50 The high-load power transmission belt according to item 1.