JPH05106708A - Toothed pulley - Google Patents

Abstract

PURPOSE:To provide a toothed pulley over which a wide width toothed timing belt is trained and which has little noise caused by air escaping from tooth grooves even at high speed rotation. CONSTITUTION:Teeth 6 of a toothed pulley 1 is formed with a communicating path 5 communicating between tooth grooves 4. When the toothed pulley 1 meshes with a timing belt, air can escape from the tooth grooves before it is compressed in the tooth groove, so that noise caused by the escapement of the compressed air is eliminated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toothed pulley used in combination with a toothed timing belt.

[0002]

2. Description of the Related Art Toothed pulleys are used in combination with toothed timing belts to transmit large power in general industrial equipment. FIG. 4 shows, as an example, an injection power transmission section in an injection unit of a so-called direct-acting injection molding machine, in which three toothed pulleys 1 (a to c) and one driving pulley 2 are provided with wide teeth. The timing belt 3 is wound around. The three toothed pulleys 1 (a to c) are used to drive a ball screw / nut mechanism (not shown) that moves the pusher plate, and the driving pulley 2 is driven by a servomotor for injection. The driving pulley 2 is also a toothed pulley.

When the toothed pulley 1 and the toothed timing belt 3 mesh with each other and rotate, the teeth of the belt 3 are fitted into the tooth spaces 4 of the pulley 1 and the air in the tooth spaces 4 (both sides of the tooth spaces 4). Is extruded in the axis s direction). When the pulley 1 rotates faster, the speed of the air pushed out also increases,
Further, since the air is compressed at the central portion of the tooth groove 4, finally, when the air is discharged from both ends of the tooth groove 4, abnormal noise is generated. In addition to this, the toothed pulley 1 is formed to have a large size and a large width in the rotation axis direction in order to transmit large power, and the toothed timing belt 3 meshing with the toothed pulley 1 is also wide, so that the air in the tooth groove 4 is Has a long distance to reach the release points on both ends. As a result, the air is strongly compressed in the tooth space 4 and the toothed pulley 1 is operated during the operation of the injection unit.
When the air escapes at the meshing portion of the toothed timing belt 3, a high-frequency jarring sound is emitted.

To alleviate this noise, it is sufficient to divide the wide belt in the width direction and shorten the air discharge path. However, if the wide belt is divided, the same transmission capacity as that before the division is obtained even if the total width is the same. Cannot be exhibited and the transmission capacity is reduced.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a toothed pulley that uses a wide timing belt with teeth and produces little noise even when rotated at high speed.

[0006]

Means for Solving the Problems A tooth of a toothed pulley is formed with a communication passage communicating between tooth spaces.

[0007]

The function of the communicating passages connecting the tooth spaces prevents the air pressure between the tooth spaces from rising.

[0008]

1 shows a first embodiment in which a toothed pulley 1 (hereinafter abbreviated as pulley 1) is provided with a single communicating passage 5. Reference numeral 6 is a tooth of the pulley 1, and a large number of teeth are formed on the outer peripheral surface of the pulley 1 in parallel with the rotation axis s at a predetermined pitch, and a tooth groove 4 is formed between the teeth 6, 6. Then, the communication passage 5 is formed in a substantially notch portion of each tooth 6 in a shape in which the tooth 6 is cut out in a direction orthogonal to the longitudinal direction of the tooth (direction of the rotation axis s), and the teeth on both sides of the tooth 6 are formed. The groove 4 communicates. Since the communication passage 5 is provided in each tooth 6, it means that the communication passage 5 is formed around the pulley 1 in the end. The depth of the communication passage 5 (the radial dimension of the pulley 1) may be within the range of the height of the tooth 6 as shown in FIG. 3 (a), or deeper than the tooth bottom as shown in FIG. 3 (b). It may be done. In addition, the communication passage 5 may have a plurality of lines.

With the above construction, the pulley 1 is provided with a toothed timing belt 3 (hereinafter abbreviated as belt 3).
When the gear 6 is driven by driving, the air pushed out by the teeth 6 meshing with the tooth groove 4 escapes to the adjacent tooth groove 4 not only from the both ends of the tooth groove 4 but also from the communication passage 5 at the center. As soon as
The air pressure does not increase in the tooth space 4. In the part where the belt 3 is wound around the pulley 1, the tooth spaces 4 on both sides are adjacent to each other.
Teeth 6 are already engaged with each other, and as shown in FIG.
In the communication passage 5 formed in the range of the height, the communication passage is blocked by the teeth 6 and air cannot escape to the adjacent tooth groove 4, but most of the air that should be escaped is the tooth 6 and the tooth groove. Four
Have escaped before the initial communication passage 5 in which they are meshed with each other is shielded, and the amount of air to be escaped in such a wound portion is small, and there is no particular problem.

However, if the communication passage 5 is formed deeper than the tooth bottom as shown in FIG. 3B, even if the teeth 6 are meshed with the tooth spaces 4 on both sides at the winding portion as described above. The communication passage 5 is not completely shielded, and even a small amount of air is not discharged from the communication passage 5 and has a high pressure in the tooth space 4. Therefore, hang a wide timing belt,
Even if it is rotated at high speed, almost no noise is generated due to air discharge. In addition, since the wide belt can be used as it is, the transmission capacity does not decrease.

FIG. 2 shows a second embodiment, in which one communicating passage 5 is formed in a spiral shape (screw thread) on the outer peripheral surface of the pulley 1, and the depth of the groove as the communicating passage 5 is shown. As in the case described above, there is a case where it is within the height range of the tooth 6 in FIG. This second
In the case of the embodiment, since the communication passage 5 is formed in a spiral shape, the portions of the communication passage 5 on the pulley 1 contact the belt 3 evenly, and the communication passage 5 is always located in the same portion of the belt 3. It is possible to prevent local fatigue of the belt 3 due to such a situation. The above is an example. The cross-sectional shapes of the tooth 6, the tooth groove 4 and the communication passage 5 in the pulley 1 are
It is not limited to the one shown. Further, the communication passage 5 may be a hole that penetrates the tooth 6 from one tooth groove 4 to the other tooth groove 4.

[0012]

EFFECT OF THE INVENTION The operation of the toothed pulley, which is carried out by winding the toothed timing belt, becomes quiet.

A wide timing belt with teeth can be used silently without being divided.

[Brief description of drawings]

FIG. 1 is a perspective view of a first embodiment.

FIG. 2 is a perspective view of a second embodiment.

FIG. 3 is a sectional view of a main part.

FIG. 4 is a perspective view showing an example of using a toothed pulley.

[Explanation of symbols]

1 Toothed pulley 2 Driving pulley 3 Toothed belt 4 Tooth groove 5 Communication passage 6 Tooth

Claims (1)

[Claims] 1. A toothed pulley having a tooth on an outer peripheral surface thereof, the tooth being parallel to a rotating shaft, wherein the tooth is formed with a communication passage communicating between tooth spaces.