JPH0351552A - Toothed belt - Google Patents

Abstract

PURPOSE:To suppress the metallic sound generated in the high speed revolution and prevent the vibration of a belt by drilling a through hole at the width center part of the tooth bottom part of the tooth in the pulley shaft direction meshed with the teeth of a pulley which are formed on the underside of the belt. CONSTITUTION:A through hole 6 is drilled at the width center part of the tooth bottom part 5 of a tooth formed on the underside of a belt 3 meshed with the teeth of a pulley 1. Therefore, the air nipped between the tooth top part and the tooth bottom part 5 is discharged in the radial direction of the pulley 1 through the through hole 6. In order to secure the discharge, a plurality of through holes 6 may be drilled when the width of the belt 3 increases more, or the discharge range may be increased as elliptics in the width direction. Since the discharge passage is formed in the direction free from the interference with the advance path of the succeeding belt teeth 4, the trouble for the discharge to be cut off in the insufficient stage is prevented.

Description

[Detailed description of the invention] "Industrial application field" The present invention relates to a toothed belt that eliminates noise.

``Conventional technology'' A toothed belt is a reliable transmission belt with axial teeth on the underside of the belt that mesh with the teeth of the pulley, preventing slippage and enabling accurate time adjustment. It combines the advantages of belt drive with the advantages of chains and gears. This has recently become widely used because it can simplify the device as a low-power constant speed ratio transmission mechanism, does not require lubrication, is easy to maintain, and does not pollute the device. .

However, as the operating speed increases, the noise emitted from toothed belts can no longer be ignored, partly because they are often used in relatively quiet surroundings, and this has become one of the problems when using toothed belts. There is. The operating noise of such a toothed belt includes: (1) Impact noise: a) Impact sound emitted when the teeth of the belt wheel collide with the teeth of the belt at the beginning of meshing; b) The tooth groove between the tooth top of the belt wheel and the helt. (2) Sound of belt string vibration (3) Noise caused by vibration of belt wheel (4) Fluid caught between belt and belt wheel at the beginning of meshing or disengagement There are five types of noise that can be considered: noise caused by the discharge or suction of air (generally air), and (5) frictional noise. However, under conditions of rotational speed of 140 rpm or less, the two main causes of noise are impact noise and belt string vibration. , and fricatives. Of these, impact noise and string vibration sound are much louder than frictional noise. Therefore, if both impact noise and string vibration sound are not noticeable, the operating noise is so quiet that it does not pose a problem.

For this reason, many proposals have been made to reduce impact noise by changing the shape of the teeth of the belt wheel, the teeth of the belt, and the tooth grooves of the belt.

However, under conditions of even higher rotational speeds, the factor described in (4) above, which had not been a problem up to then, becomes a major cause of impact noise.

That is, this impact sound is mainly a compressed air burst sound when the air existing between the belt teeth and the pulley teeth is compressed and is suddenly discharged from a narrow gap.

There are proposals in Japanese Patent Publication No. 47-34433 and Utility Model Publication No. 62-46939 intended to eliminate the impact noise of the transmission mechanism. The former refers to a pulley with a tooth profile that meshes with the tooth profile of the belt, and the tooth profile has grooves and holes that communicate with the outside at least at a portion of the engagement surface between one pitch and the compressed air generated by the engagement with the pulley. ``Noise prevention device for toothed belt transmission, which is characterized by being configured so that it can be discharged into the outside air.'' The latter is ``(1) A noise prevention device in the longitudinal direction of the belt on the bottom of the main body in which a tensile member is embedded. A toothed belt that has teeth at a constant pitch at right angles, and two or more V grooves are provided in the teeth along the longitudinal direction of the belt; (2) teeth that mesh with the teeth of the toothed belt; a pulley having a rib along the bottom surface that is provided on the bottom surface and can be fitted into the V groove of the toothed belt; (3) the protrusion amount of the rib from the bottom surface of the pulley is determined by A Helt transmission device characterized in that the amount of protrusion from the bottom of the pulley is less than or equal to the amount of protrusion from the bottom surface of the pulley.

``Problem to be solved by the invention aJ Among the problems described in the prior art, in the former case, the pulley teeth must be carved with grooves and holes. Under high-speed rotation, the succeeding Herto tooth crest blocks the path of the slot in the discharge path before discharge is completed, resulting in a problem in which impact noise is insufficiently eliminated.

In addition, in the latter case, as in the former case, ribs must be attached to the pulley, which not only requires time and effort in machining the pulley, but also requires time and effort to create a V-groove for the belt teeth. Maintaining the strength of the belt teeth Because the depth is limited to a range of 60 to 80% from the top of the teeth and does not reach the root of the teeth, the outflow of compressed air through the grooves is insufficient, especially when rotating at high speeds. There is a problem in that it is impossible to eject the air from below, and it is impossible to eliminate impact noise at all.

The present invention has been made in view of the above-mentioned problems of the conventional technology, and its purpose is to eliminate the need for any processing on the pulley, which is difficult to process, and to improve only the belt side. This purpose is to propose a toothed bell 1 that can completely discharge compressed air under high-speed rotation with simple modifications that can be applied to existing products.

"Means for Solving the Problems" In order to achieve the above object, the toothed helt according to the present invention is provided at the width center of the bottom of the teeth in the axial direction of the pulley that meshes with the teeth of the pulley attached to the lower side of the belt. A through hole is drilled in the part.

"Operation" In the toothed belt of the present invention, the air compressed between the pulley tooth top and the belt tooth bottom is discharged in the radial direction of the pulley through the through hole 7.

Since this discharge path is oriented in such a direction that there is no possibility that the retreat path will be blocked by the following belt teeth, the discharge is not accompanied by any harmful effects, and rupture of the compressed air is reliably prevented.

"Example" Examples will be described with reference to the drawings.

FIGS. 1a and 1b are a longitudinal sectional view showing the engagement between the bell 1 and the pulley of the present invention, and an enlarged perspective view of the belt. In the figure, a through hole 6 is bored in the center width of the bottom portion 5 of the tooth 4 attached to the lower side of the belt 3 that meshes with the tooth 2 of the pulley I.

Accordingly, the air trapped between the top portion of the tooth 2 and the bottom portion 5 of the tooth is discharged in the radial direction of the pulley 1 through the through hole 7L6 according to the structure of the present invention described above.

In order to ensure the above-mentioned discharge, the through hole 6 is single in the width direction in the illustrated example, but if the width is larger, multiple holes may be bored, or an ellipse in the width direction may be formed. It is also possible to expand the drainage range.

Since the discharge path is in a direction that does not interfere with the path of the succeeding helt teeth at all, there will be no inconvenience such as being blocked when the discharge is insufficient.

"Effects of the Invention" Since the present invention is configured as described above, it produces the following effects.

It is sealed between the top of the pulley teeth and the bottom of the belt teeth with only a simple drilling process that does not require any processing on the pulley side and can be easily applied to existing products. By reliably discharging the trapped air without any inconvenience, it is possible to reduce the metallic noise generated during high-speed rotation and eliminate belt vibration.

[Brief explanation of drawings]

FIGS. 1a and 1b are a longitudinal sectional view and an enlarged perspective view of the belt, respectively, showing the engagement between the belt of the present invention and the pulley. DESCRIPTION OF SYMBOLS 1...Pulley, 2...Teeth, 3...Belt 4...Teeth, 5...Tooth bottom, 6...Through hole. Procedural amendment (voluntary) 1. 2. 3. Incident display level rIi. 2001 Patent Application No. 185562 Name of the invention Relationship to the toothed belt amendment case Patent applicant name Yoshifumi Tsuchiya 5. Scope of claims to be amended and detailed description of the invention 6. Contents of the amendment (1) The description in the claims section is amended as shown in the attached sheet. (2) In the first line of page 6, it says, “Full length (3
) Add the following sentence at the end of page 7, line 6. ``The through holes 6 are naturally formed over the entire length of the belt 3.'' 12 Claims ``The pulley shaft that meshes with the teeth of the pulley attached to the underside of the long blue-bellied belt.'' A toothed belt characterized by having a through hole bored in the center width of the bottom of the tooth in the direction.

Claims (1)

[Claims] A toothed belt characterized in that a through hole is formed in the center width of the bottom of the teeth in the axial direction of the pulley that mesh with the teeth of a pulley attached to the lower side of the belt.