JPH05141571A - Speed reducer for driving butterfly valve - Google Patents

Abstract

PURPOSE:To prevent the precedent phenomenon of a valve body due to intermittent racing of a worm shaft, and to prevent a bad influence due to impact upon a speed reducer for driving a butterfly valve including gears, when a self-lock mechanism of a worm wheel mechanism fails to function by the vibration due to irregular flow inside a piping so that a force in the closing direction is exerted on the valve body of a butterfly valve. CONSTITUTION:A speed reducer for driving a butterfly valve consisting of a worm wheel 2 that has been fitted to the valve shaft 1 of the butterfly valve and a worm 3 that has been engaged with the worm wheel 2 is provided with a pressing means 6 for restraining the abnormal rotation of the worm 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a butterfly valve drive speed reducer in which a worm gear is attached to a valve shaft of a butterfly valve, and the worm meshes with the worm gear.

[0002]

2. Description of the Related Art A worm gear mechanism as shown in FIG. 2 is used in a butterfly valve driving speed reducer. In this worm gear mechanism, a worm 20 and a worm gear 21 mesh with each other. Then, the valve shaft 22 of the butterfly valve is fitted into the worm gear 21, and the torque input from the worm shaft 23 side is output from the worm gear 21 side to output the worm gear 21.
Is rotated, the valve shaft 22 of the butterfly valve is rotated to open and close the valve body of the butterfly valve. However, normally, the input from the worm gear 21 side is not output to the worm 20 side. That is, the worm 20 does not rotate due to the input torque on the worm gear 21 side, and this is called a self-lock mechanism of the worm gear mechanism. Due to the self-locking mechanism of the worm gear mechanism, normally, the valve body of the butterfly valve is not closed by the force of the fluid.

[0003]

However, due to the shape of the piping route to which the butterfly valve is attached and the vibration due to the irregular flow in the piping, the self-locking mechanism of the worm gear mechanism fails and the preceding phenomenon of the valve body occurs. That is, the force in the closing direction acts on the valve body of the butterfly valve, and the worm shaft
The worm gear is rotated before the rotation of the drive unit etc.
There was a problem that the phenomenon that 21 turns in the closing direction occurs. At this time, an excessive shock is applied to the worm shaft 23, which adversely affects the butterfly valve driving speed reducer including the gears together with the shock noise.

The present invention has been made in order to solve such a conventional problem, and an object thereof is to provide a butterfly valve drive speed reducer in which a preceding phenomenon of a valve body does not occur.

[0005]

A butterfly valve drive speed reducer according to the present invention is a butterfly valve drive speed reducer comprising a worm gear mounted on a valve shaft of a butterfly valve and a worm meshing with the worm gear. Is provided with a pressing means for suppressing abnormal rotation.

[0006]

With the above structure, the pressing means for suppressing the abnormal rotation of the worm acts as a resistance against the rotation of the worm shaft by an arbitrary pressing force, and prevents intermittent idling of the worm shaft due to the preceding phenomenon of the valve element.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. FIG. 1 is a partial cross-sectional view of a butterfly valve drive speed reducer according to an embodiment of the present invention. In FIG. 1, 1 is a valve shaft of a butterfly valve, and a worm gear 2 is attached to the valve shaft 1.
Is attached, and the worm 3 is further meshed with the worm gear 2. Although not shown, a drive handle or a drive unit is connected to one end of the worm shaft 4, and the drive handle or drive unit rotates the worm 3 to rotate the worm gear 2 and the valve. The shaft 1 is rotated to open and close the valve body of the butterfly valve.

The bearing portion 5 on the other end side of the worm 3 is provided with pressing means 6 for suppressing abnormal rotation of the worm 3. The pressing means 6 is composed of a pressing pin 7, a pressing spring 8, a pressing force adjusting bolt 9, and a lock nut 10. Then, the bearing portion 5 on the other end side of the worm 3
A mounting hole 11 is formed through the worm shaft 4 in the vertical direction, a pressing pin 7 is loosely fitted in the bottom of the mounting hole 11, and a pressing spring 8 is fitted from behind the pressing pin 7, and A pressing force adjusting bolt 9 is screwed from the rear side of 8 to press the pressing pin 7 against the worm shaft 4 side to suppress the rotation of the worm shaft 4. The lock nut 10
Adjusts the tightening position of the pressing force adjusting bolt 9 and stops the slack.

Next, the operation of the butterfly valve driving speed reducer in the above configuration will be described. When the self-lock mechanism of the worm gear mechanism is operating normally, even if the valve shaft 1 of the butterfly valve tries to rotate due to the force of the fluid, the self-lock mechanism does not rotate the valve shaft 1 of the butterfly valve.

However, the self-locking mechanism of the worm gear mechanism is lost due to the vibration generated by the irregular shape of the piping route and the pulsation of the fluid. For this reason, when a fluid force in the closing direction is applied to the butterfly valve, the preceding phenomenon of the valve element occurs due to intermittent idling of the worm gear 2 and an excessive impact is applied, which causes an impact noise and adversely affects the butterfly valve drive speed reducer including the gear. give. Therefore, the rotation of the worm shaft 4 is stopped by the pressing pin 7 of the pressing means 6,
The preceding phenomenon of the valve body caused by the idling of the worm 3 is suppressed.

By tightening or loosening the pressing force adjusting bolt 9, it is possible to obtain an arbitrary pressing force for the worm shaft 4, and it is possible to adjust the force for suppressing the rotation of the worm shaft 4.

The pressing means 6 of the present invention is not limited to the above-mentioned embodiment, but may be a disk brake or the like as long as it has a structure for suppressing the rotation of the worm shaft 4.

In the above embodiment, the case where the pressing means 6 is provided at the tip of the worm shaft 4 has been described. However, in the present invention, the place where the pressing means 6 is provided is not limited to such a position, and any part of the worm shaft 4 is described. It may be provided in.

[0014]

As described above, according to the present invention, by providing the pressing means for suppressing the abnormal rotation of the worm, the intermittent idling of the worm due to the preceding phenomenon of the valve body can be prevented.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view of a butterfly valve driving speed reducer according to an embodiment of the present invention.

FIG. 2 is a schematic diagram of a worm gear mechanism used in a conventional butterfly valve driving speed reducer.

[Explanation of symbols]

 1 valve shaft 2 worm gear 3 worm 6 pressing means

Claims (1)

[Claims] 1. A butterfly valve drive speed reducer comprising a worm gear attached to a valve shaft of a butterfly valve and a worm meshing with the worm gear, wherein pressing means for suppressing abnormal rotation of the worm is provided. A speed reducer for driving a butterfly valve.