JPH03295433A - Torque measuring instrument of electrically operated valve driving device - Google Patents

Abstract

PURPOSE:To diagnose the driving device by a simple device by fitting the torque sensor to the head part of a drive sleeve and by providing a reaction receiver which receives the rotational reaction of the torque sensor. CONSTITUTION:A worm 5 is fitted on a spline shaft 4 and slides axially, so as the sheet bearing of a valve increases, the worm 5 moves axially while pressing a torque spring 7. When the spring 7 is shrinked until said movement corresponds to predetermined sheet bearing, an actuator 9 which consists of a lever or a rack and a pinion is operated to break the contact of a torque switch 8, thereby stopping a driving motor 1. Even when the motor 1 stops here, it is locked by a worm gear 6, so constant sheet bearing is maintained by the spring 7 until the motor 1 reverses. Consequently, it can be diagnosed whether or not the driving device generates proper driving torque.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a torque measuring device that can be attached and detached with a simple configuration in a valve stem drive device of a large electric valve.

[Conventional technology]

In an electric valve, it is preferable to appropriately measure the torque of the drive device in order to diagnose whether the valve stem is being driven so that the valve body and valve seat can maintain appropriate seat surface pressure.

By the way, currently, after the torque setting value is measured when the drive device is shipped from the factory, there is no method of reconfirming the torque at the site where the electric valve is operated. Therefore, once the output torque is set based on the output torque data for the torque setting scale, the set value is not confirmed. Similarly, since changes over time in the torque setting value are not checked, there is a problem in that valve malfunctions occur again and again.

On the other hand, there is an example in which a manufacturer of a drive device carries a large measuring device used for measurements at the time of factory shipment to the site and measures torque. This measuring device installs a rotating disk on a simulated valve stem, and uses a load cell to measure the pressure generated when the rotation of the disk is forcibly stopped. For this purpose, the drive device to be measured is removed separately, attached to a measuring instrument installed at a predetermined location, and the driving torque is transmitted to the simulated valve stem.
This method measures the relationship between the torque setting value and the reaction force that the load cell receives.

[Problem to be solved by the invention]

However, in order to use this measuring device, the following conditions must be met. In other words, ■ the drive device must be removed from the valve body, ■ the drive device must be transported from the site to another location because a large space is required to use the measuring device, and ■ this meter requires Since it is possible to measure only the output torque for a predetermined scale value, the relationship between the scale and torque will not be clear unless the scale is changed at three or more points and measured. Since it must be operated by a control panel, if the motor output and power source are different, it is necessary to create a control panel that is compatible with the drive device. As described above, the measuring instruments used at the time of shipment have too many restrictions, and it is practically impossible to use them for periodic diagnosis.

As described above, conventional measuring instruments measure the rotational reaction force of a simulated valve stem using a load cell, but it is also possible to obtain similar diagnostic results by measuring the driving torque of the valve stem itself. That is, by detecting the drive torque, it is possible to diagnose whether the seat surface pressure is adequate or not by simple calculation. The present inventor has developed a measuring device focusing on this point, and the torque of an electric valve drive device can be measured by simply attaching a measuring device with a simple configuration without taking the trouble of removing the drive device. The purpose is to provide a measuring device.

[Means to solve the problem]

In order to achieve the above-mentioned object, the present invention transmits the drive of a motor to a worm gear via a worm slidably provided on a spline shaft, and further transmits the rotation of this worm gear to a drive sleeve screwed onto a valve stem. In the electric valve driving device that moves the valve stem up and down in the axial direction,
A detection drive sleeve disconnected from the valve stem is used in place of the drive sleeve, and a torque sensor is fitted onto the head of the drive sleeve with a square shaft, and the rotational reaction force of the torque sensor is received. We used a method of installing a receiver.

In the above-mentioned means, the worm gear of the drive device rotates the drive sleeve, and this drive sleeve is fixed vertically, so the threaded valve stem moves up and down as it rotates. In the case of a detection drive sleeve, the connection relationship with the valve stem is severed without being screwed together, and the sleeve functions independently to receive rotational force, and this force is directly transmitted to the actuator of the torque sensor. In addition, the reaction force receiver acts to restrict the rotational movement of the torque sensor.
Due to the rotational force of the detection drive sleeve and the regulation by the reaction force receiver, rotational stress is applied to the torque sensor, which converts this stress into an electrical signal. Therefore, the torque sensor performs the function of accurately capturing the torque of the drive device.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will now be described in detail with reference to the attached drawings. First, FIG. 1 shows the configuration of a drive device for driving a valve stem. Here, ■ is a drive motor, 2 is a helical gear attached to the motor shaft, 3 is a reduction gear, 4 is a spline shaft that rotates coaxially with the reduction gear 3, and the spline has a worm 5 that is slidable in the axial direction. is inserted. A worm gear 6 meshes with the worm 5 and drives a centrally attached valve stem (not shown). 7 is a torque spring, 8 is a torque switch, and the actuator 9 of this torque switch is a lever or a lever.

The sliding movement of the worm 5 is detected by the pinion, and the contact 10 is opened and closed.

With such a configuration, the rotation of the drive motor 1 is transmitted to the valve stem. First, the rotational force of the drive motor 1 passes through the helical gear 2 and rotates the worm 5.

This causes the worm gear 6 to rotate. Inside the worm gear 6, there is a NAND that is screwed into the thread of the valve stem, and a drive sleeve that receives the drive torque of the worm gear 6 is fixed on the outer periphery, thereby transferring the rotational force to the valve. The signal is transmitted to the valve rod, and the valve rod performs up and down movement, which is the opening and closing operation of the valve. On the other hand, since the worm 5 is fitted onto the spline shaft 4 and is structured to slide in the axial direction, it moves in the axial direction while pushing the torque spring 7 as the valve seat surface pressure increases. When this movement compresses the torque spring 7 until it corresponds to a predetermined seat surface pressure, the actuator 9 consisting of a lever or rack and a binion is actuated, the contact of the torque switch 8 is opened, and the drive motor 1 is activated. make it stop. Here, even if the drive motor 1 stops, since it is locked by the worm gear 6, a constant seat surface pressure is maintained by the torque spring 7 until the drive motor 1 rotates in the reverse direction.

In the present invention, a measuring instrument having the structure shown in FIG. 2 is used to diagnose whether or not the above-described drive device is generating an appropriate drive torque. Here, reference numeral 11 denotes a drive sleeve for inspection, with a square hole 12 in the axis of the head, and a worm gear 6 of the drive device on the outer periphery like a normal drive sleeve.
The structure is such that the valve stem is engaged with the valve stem and receives its drive torque, and the drive to the valve stem is cut off without forming a NAND on the inner periphery.

A torque sensor 13 has a square shaft 14 that fits into the square hole 12 of the drive sleeve 11, and converts the drive torque into an electrical signal. Furthermore, once the torque sensor 13 rotates together with the test drive sleeve 11, it will not be possible to detect torque, so it is necessary to keep it fixed. Therefore, the reaction force receiving arm 16 is fitted to another square shaft 15 of the torque sensor, and the arm 16 is combined with the reaction force receiving groove 18 of the reaction force receiving flange 17 fixed with bolts instead of the lid on the top of the drive device. Accordingly, the torque sensor 13 is fixed to the valve body. FIG. 3 shows an outline of a state in which these are combined.

Note that by replacing the reaction force receiving flange 17, this measuring instrument can be attached to any size motor-operated valve. To this end, this embodiment has a configuration in which four parts are assembled, but if the torque sensor 13 is to be used only for a specific electric valve, the torque sensor 13 can be attached to the reaction force receiving flange 17.
It is possible to perform similar measurements even if it is fixed to .

By detecting the output from the torque sensor 13 in this way, it is also possible to detect the opening/closing of the contacts of the torque switch provided in advance on the valve body, detect the displacement angle, and at the same time detect the current of the drive motor. The appropriate torque of the drive device can be diagnosed simply by detecting and inputting these parameters into a certain calculation formula.

[Effects of the Invention] In the present invention, driving torque can be directly measured simply by replacing some parts of the valve body and combining it with a torque sensor, which is extremely efficient compared to the conventional method of measuring torque using a load cell. Diagnosis of the drive unit is now possible with a simple device.

Also, when assembling it, remove the lid of the valve body, pull out the drive sleeve, replace it with a detection drive sleeve, and then fix the reaction force receiving part to the valve body.
Preparation for diagnosis is completed with a simple operation of regulating the rotation of the torque sensor using this reaction force receiving part, so it does not require an expert and can be easily installed in a short time on site. It has been possible to provide a measuring device that has a number of advantages.

[Brief explanation of drawings]

FIG. 1 is a perspective view of an electric valve driving device using a measuring device of the present invention, FIG. 2 is a perspective view of the measuring device of the present invention, and FIG. 3 is a partially sectional view showing its assembled structure. In addition, in the figure 1... drive motor, 2... helical gear,
3... Reduction gear, 4... Spline shaft, 5... Worm, 6... Worm gear, 7... Torque spring, 8... Torque switch, 9... Actuator, 10... Contact, 11... Drive sleeve for inspection, 12... Square hole, 13... Torque sensor, 14...
15... Square shaft, 16... Reaction force receiving arm, 17...
・Reaction force receiving flange, 18...Reaction force receiving groove. that's all

Claims (1)

[Claims] 1. The drive of the motor is transmitted to a worm gear via a worm slidably mounted on a spline shaft, and the rotation of this worm gear is further transmitted to a drive sleeve screwed onto a valve stem, and the valve stem is moved in the axial direction. In a drive device for an electric valve that moves up and down, a detection drive sleeve disconnected from the valve stem is used instead of the drive sleeve, and a torque sensor is fitted with a square shaft to the head of the drive sleeve, and the torque sensor is A torque measuring device for an electric valve drive device, characterized in that a reaction force receiver is provided to receive rotational reaction force of a sensor.