JP2003307259A - Toothed belt power transmission system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve durability in a belt in a toothed belt power transmission system wherein frictional resistance between a belt and a pulley tooth flank is lowered by the attachment of oil, water and the like. <P>SOLUTION: A distance between two tooth flanks opposite to each other of a toothed pulley 20B represented by a tooth shape PT and engaged with a tooth of a toothed belt 10 represented by tooth shape BT, is narrowed. When the belt tooth flank is engaged with the pulley tooth flank, the belt tooth flank is compressed by the pulley tooth flank. The belt tooth flank and the pulley tooth flank are closely kept into contact with each other to make backlash zero. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a belt transmission system for transmitting power to a driven pulley by using a toothed belt, and more particularly to a belt transmission system used in an environment where oil or water adheres to the belt or pulley. .

[0002]

2. Description of the Related Art In a toothed belt transmission system which is driven at high speed or under a large load for a long time, in order to improve durability of the toothed belt and reduce noise, A backlash is provided for meshing with the attached belt pulley to prevent interference between the tooth flank of the belt and the tooth root of the pulley to reduce stress concentration at the tooth root.

[0003]

Among such toothed belt transmission systems, for example, in a toothed belt transmission system used in a car washer or the like, water, detergent, wax, etc. scattered due to the structure thereof are belts or pulleys. And enters between the tooth flank of the belt and the tooth flank of the pulley to reduce the frictional resistance between the tooth flanks. Further, in a toothed belt transmission system used for machine tools and the like, oil as coolant adheres to the belt and pulley, so that oil enters between the tooth surfaces of the belt and the pulley and frictional resistance decreases. In the case of a toothed belt transmission system that is used in an environment exposed to water or oil in this way, the adhered water or oil (medium) functions as a lubricant in the mesh between the belt and pulley, It reduces the frictional resistance between the surface and the tooth flank of the pulley. When the frictional force between the tooth flank of the belt and the tooth flank of the pulley is reduced, the load and driving torque may fluctuate and the belt teeth may be swung between the pulley teeth. Durability is significantly reduced.

According to the present invention, the durability of the belt is improved in a toothed belt transmission system which is used in an environment in which a medium such as oil or water is attached to reduce the frictional resistance between the belt tooth surface and the pulley tooth surface. The purpose is to improve.

[0005]

The toothed belt transmission system of the present invention transmits power by using a toothed belt and a toothed pulley to reduce frictional resistance between the tooth flank of the belt and the toothed surface of the pulley. A toothed belt transmission system used in an environment in which a medium to be driven is present, characterized in that when the toothed belt meshes with a toothed pulley, there is no backlash between the belt tooth and the pulley tooth. I am trying.

For example, the tooth profile of the toothed belt and the tooth profile of the toothed pulley are substantially the same. Further, for example, a distance between two tooth surfaces facing each other in two adjacent pulley teeth of the toothed pulley is relatively smaller than a distance between two tooth surfaces of one belt tooth of the toothed belt, and Upon meshing with the toothed pulley, the tooth flanks of the belt teeth are compressed to the tooth flanks of the pulley teeth. When the toothed belt and the toothed pulley have substantially the same tooth profile as in the former case, the backlash can be made zero while minimizing the energy loss due to the compression of the belt teeth. On the other hand, in the latter case where the belt teeth are compressed and meshed with the pulley teeth, the backlash can be more surely set to zero.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view when a part of a toothed belt used in the toothed belt transmission system of the present embodiment is cut out.

The toothed belt 10 is provided with a tooth rubber layer 12, a tooth portion 14 and a tooth bottom portion 15 are alternately and integrally formed on one surface of the tooth rubber layer 12, and the outer side thereof is a tooth cloth 11.
Is covered by. Further, the toothed belt 10 has a tooth rubber layer 1
2 includes a back rubber layer 16 integrally applied to the other surface of the two, and a plurality of core wire elements 18 embedded in a boundary surface between the tooth rubber layer 12 and the back rubber layer 16. The cord element 18 is obtained, for example, by spirally winding a pair of cords along the longitudinal direction of the toothed belt 10. Further, short fibers 17 such as aramid are mixed in the tooth rubber layer 12.

FIG. 2 is a diagram showing a belt tooth profile of the toothed belt 10 and a pulley tooth profile of the toothed pulley in the toothed belt transmission system according to the embodiment of the present invention. The tooth profile of the pulley of this embodiment will be described with reference to FIGS. 2 and 3.

2 and 3 are views showing the relationship between the belt tooth profile and the pulley tooth profile in the toothed belt transmission system of this embodiment. 2 and 3, a curve BT shows an example of the tooth profile of the toothed belt 10, and the curve PT
Reference numerals 1 and PT2 show examples of tooth profiles of toothed pulleys 20A and 20B used with the toothed belt 10, respectively. In FIG. 2, the pulley tooth profile PT1 substantially coincides with the belt tooth profile BT and the backlash is substantially zero. On the other hand, in the pulley tooth profile PT2 of FIG. 3, the distance between two adjacent teeth (distance between opposing pulley tooth surfaces) is greater than the distance between the tooth surfaces of one tooth of the toothed belt 10 meshing with this. Is also narrow. That is, the backlash is negative before the toothed belt 20B meshes with the toothed pulley 10, and when the toothed belt 20B meshes with the toothed pulley 10, the belt tooth surface is compressed to the pulley tooth surface. The mesh is engaged in the state and the backlash is 0.

FIG. 4 is a graph showing the effect of the presence or absence of backlash on the effective tension of the belt when oil adheres and the frictional force between the tooth surfaces is reduced. The toothed belt transmission system is driven at 4000 rpm. The result is shown.
The horizontal axis is the belt attachment tension (unit is Newton (N)), and the vertical axis is the dimensionless effective tension. That is,
The vertical axis of the graph represents the effective tension generated as a unit load when the toothed belt transmission system with backlash is driven in a state where oil is not attached, and the effective tension is expressed as a load ratio (percentage). . The polygonal line E1 shows the effective tension when the toothed belt transmission system with backlash is driven with oil attached, and the polygonal line E2 shows the toothed belt transmission system without backlash (this embodiment).
It shows the effective tension when the motor is driven with oil attached.

As is apparent from the graph, the effective tension (generated load ratio) is smaller when there is no backlash at any belt mounting tension. For example, when the standard belt mounting tension is 100 N, the generated load ratio is reduced by about 27%.
Even in the vicinity of the belt attachment tension of 50 N, the drop is 20% or more.

FIG. 5 shows the results of a durability test of the toothed belt in a state where oil is adhered (a frictional force between tooth surfaces is reduced). FIG. 6 shows the arrangement of the pulleys and the belt at this time. As shown in FIG. 6, the toothed belt 40 used in the test is a pulley with a driving tooth (19YU).
30 and a driven toothed pulley (38YU) 31 are suspended, and tension is applied by an idler 32.

A bar graph A shows the case where there is backlash, and a bar graph B shows the case where there is no backlash (corresponding to this embodiment). Environmental temperature is 120 ℃
The rotation speed was 6000 rpm. As shown in the figure, in the case of backlash, the belt tooth was broken (the tooth fell off from the root) in 700 hours, but in the case of no backlash, the belt was chipped in 1100 hours. Not too much. Further, regardless of the presence or absence of backlash, the wear of the tooth cloth occurs and progresses with the passage of time, but the result without wear of backlash showed superior wear resistance.

As described above, according to the present embodiment, in a toothed belt transmission system used in an environment where water, oil, etc. adheres and the frictional resistance between the tooth surfaces of the belt and the pulley decreases, the belt is generated. The effective tension of the toothed belt can be remarkably reduced and the durability of the toothed belt can be remarkably improved.

The tooth profile of the toothed belt is not limited to this embodiment, and may be any shape as long as the backlash is 0 when the belt is meshed with the pulley. For example, a trapezoidal toothed belt or a helical toothed belt may be used.

[0017]

As described above, according to the present invention, a toothed belt used in an environment in which a medium such as oil or water adheres to reduce the frictional resistance between the belt tooth surface and the pulley tooth surface. In the transmission system, the durability of the belt can be improved.

[Brief description of drawings]

FIG. 1 is a perspective view in which a part of a toothed belt used in a toothed belt transmission system to which the present invention is applied is cut away.

FIG. 2 is a diagram showing respective tooth profiles when a tooth profile of a toothed belt and a tooth profile of a toothed pulley substantially match each other.

FIG. 3 is a diagram showing respective tooth profiles when a gap between pulley teeth meshing with a belt tooth is small.

FIG. 4 is a graph showing the effect of the presence or absence of backlash on the effective tension of the belt when oil is attached (the frictional resistance between the tooth surfaces is reduced).

FIG. 5 is a graph showing the influence of the presence or absence of backlash on the durability of the belt when oil is attached (the frictional resistance between the tooth surfaces is reduced).

FIG. 6 is a layout diagram of a durability test.

[Explanation of symbols]

10 toothed belt 12 teeth 15 Tooth bottom 20A, 20B toothed pulley

Claims (3)

[Claims] 1. A tooth used in an environment in which a medium that transmits power by using a toothed belt and a toothed pulley and reduces frictional resistance between the tooth surface of the belt and the tooth surface of the pulley is present. A toothed belt transmission system, wherein when the toothed belt meshes with the toothed pulley, there is no backlash between the belt tooth and the pulley tooth. 2. The toothed belt transmission system according to claim 1, wherein the toothed shape of the toothed belt and the toothed shape of the toothed pulley substantially match each other. 3. A distance between two facing tooth surfaces of two adjacent pulley teeth of the toothed pulley is relatively smaller than a distance between two tooth surfaces of one belt tooth of the toothed belt. The toothed belt transmission system according to claim 1, wherein tooth surfaces of the belt teeth are compressed by tooth surfaces of the pulley teeth when the toothed belt and the toothed pulley are meshed with each other.