JPS6134581B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a control valve that supplies fluid to or discharges fluid from a control system so as to bring the control system into a desired state.

As disclosed in Japanese Utility Model Publication No. 38-24061, conventional control valves constantly detect the position of the valve stem using a position detection means such as a potentiometer. However, since the valve closing position corresponds one-to-one to a specific signal value of the position detection means, there may be delays in signal processing, play in the reduction gear or threaded joint, bumps, or wear of the valve seat. If a discrepancy occurs in this one-to-one correspondence, the valve may be incompletely closed, or excessive valve-closing force may be applied, resulting in damage to the valve portion, gear, and motor.

Therefore, the present invention prevents incomplete valve closing or excessive valve closing operation even if there is a delay in signal processing, rattling or bumping of the reduction gear or threaded joint, or wear of the valve body or valve seat. The purpose of this invention is to obtain a control valve in which the valve part, gear, and motor will not be damaged by force.

The technical means of the present invention taken to achieve the above object is that the control means receives the target signal and the detection signal of the control system state and issues an operation signal, and the operation means receives this operation signal and In a control valve that operates a control valve and adjusts the opening degree of a fluid passage communicating with or from a control system, the rotation shaft of a ball screw is applied to the output shaft of the operating means, and the shaft receives rotational force and is displaced in the axial direction. The valve shaft of the valve means is connected to the reciprocating member of the ball screw, and the rotating shaft of the ball screw is urged in the closing direction of the valve means by the elastic means, and the movable end of the elastic means is A transmission member is attached so as to be displaced along with the compression displacement, and a limit switch that sends a signal to the operating means to stop operation in the valve closing direction is incorporated into the control means, and the limit switch is driven at a position where the transmission member is displaced by a predetermined amount. It is something that is attached to.

The operation of the above technical means is as follows.

After the valve is closed, the elastic means is compressed, and when the transmission member that is displaced along with the compressed displacement is displaced by a predetermined amount, a signal is issued from the limit switch to stop the operation in the valve closing direction, so the valve body and valve seat are not worn out. too,
Alternatively, even if play occurs in the operating force transmission system, the valve will always be completely closed while receiving a predetermined urging force from the elastic means. Further, even if signal processing is delayed or solid matter is caught between the valve body and the valve seat, the elastic means acts as a buffer, so the valve part will not damage the gear or motor. For this reason, the accuracy of detecting the valve closing position may be low, and an inexpensive micro switch (limit switch) may be used.

A detailed explanation will be given below based on the illustrated embodiment.
FIG. 1 is a block diagram schematically showing the case where the control valve according to the present invention is used as a so-called pressure reducing valve.
A downstream piping 2 of the valve means 1 serves as a control system, and the pressure of the control system 2 is detected by a pressure detection means 4. Reference numeral 5 denotes a control means, into which a signal from the pressure detection means 4 is input. A target value representing a desired pressure state of the control system 2 is inputted to the control means 5 from the input means 6 . The control means 5 has a digital computer consisting of an LSI, stores the target value, performs comparisons and calculations between the target value and the detected pressure value, and outputs a predetermined operation signal according to the stored program. The operating means 7 has a step motor, and the above-mentioned operating signal is sent to the driver bar 8 from the control means. This operation signal generally includes information on the direction of rotation of the motor (forward or reverse) and the number of rotation steps per unit time. In this way, the opening degree of the valve means 1 is adjusted by the operating means 7, and if the pressure of the control system 2 is lower than the target value, the valve means is operated to increase the valve opening degree, and the pressure fluid from the inlet side piping 3 is controlled. The supply ratio is increased, and conversely, if the pressure in the control system 2 is greater than the target value, the valve means 1 is operated to reduce the valve opening, and the ratio of fluid pressure supply from the inlet side piping 3 is reduced. be done. In this way, a control valve that can be accurately controlled using a small LSI digital computer and a step motor can be obtained. With the miniaturization of computers, a single control valve equipped with a computer is now available instead of being remotely controlled. Because of its large output, the step motor allows for a simple reduction mechanism, and a ball screw can be used. 9 indicates a valve closing position detection means. For this purpose, means is used to detect the load on the valve shaft that transmits the contact force when the valve body contacts the valve seat. A signal from the valve closing position detecting means is sent to the control means and processed according to a computer program, and a signal is sent from the control means to the operating means to prohibit operation in the valve closing direction.

FIG. 2 shows a more specific example of the embodiment shown in FIG. 1 above. However, this embodiment embodies only the section A in FIG. 2, which consists of the valve means 1, the operating means 7, and the valve closing position detecting means 9, and the other parts are the same as those in FIG. 1, and their explanation will be omitted.

Regarding the parts constituting the valve means 1, 10 indicates a valve body, and this body 10 has an upstream passage 11 communicating with an upstream piping (not shown), a downstream passage 12 and a downstream passage communicating with a downstream piping (not shown). The opening 14 communicates with the passage 12. Reference numeral 15 indicates a flange portion for connection with other piping. Reference numeral 13 indicates a valve port that communicates the upstream passage 11 and the downstream passage 12, and is formed by a cylindrical valve seat member 18 that is airtightly inserted from the opening 14 via gaskets 16 and 17. 1
Reference numeral 9 indicates a communication hole provided in the valve seat member 18. After the valve seat member 18 is inserted into the opening 14, the valve body 10 is tightened using a tightening means (not shown) such as a bolt or nut.
The valve seat member 18 is held between the partition wall inside the valve body 10 and the lid 20. Reference numeral 21 indicates a gasket that maintains airtightness between the valve body 10 and the lid body 20. 22 is the valve seat member 1
8, the valve body 22 slides airtightly within the valve seat member 18 via an O-ring 23 to change the opening degree of the valve port 13. 24
indicates a communication hole that penetrates the valve body 22 and introduces upstream pressure into the upper surface chamber 25 of the valve body 22, cancels out the fluid pressure acting on the upper and lower surfaces of the valve body 22, and allows the valve body 22 to move with a small driving force. Allows sliding. Reference numeral 26 indicates a valve shaft that drives the valve body 22, and is connected to the valve body 22 using a collar portion 58 and a nut 59. This valve stem 2
6 protrudes to the outside through the lid 20, and its penetrating portion is sealed by a gland packing 28 tightened by a plug 27 and an O-ring 29. 30 indicates a gasket that maintains airtightness between the plug 27 and the lid body 20.

Next, a step motor 31 is used as the operating means 7, and this step motor 31 is carried by a mounting tube 32 fixed to the lid 20.
Further, this mounting cylinder 32 is attached to the lid body 20 by a tightening member used when fixing the lid body 20 to the valve body 10.
is fixed to. This mounting cylinder 32 has a flange part 42 at the lower part in order to stably fix it to the lid body 20, and is hollow, and an annular step part 3 is provided at the upper part of the hollow inner surface.
3 is formed, and a step motor 3 is attached to this stepped portion 33.
The first protrusion 34 is joined, and the step motor 31 is accurately positioned. An output shaft 35 protrudes from the lower surface of the step motor 31, and the lower end of the output shaft 35 has a substantially inverted L-shaped cross section and forms a part of a joint portion 36. Reference numeral 57 indicates a manual operation shaft that is formed coaxially with the output shaft and projects from the top, and is used when manually changing the opening degree of the valve means 1 by applying a spanner tool. Corresponding to the output shaft 35 is a driven shaft 37 whose upper end is formed into a substantially L-shaped cross section, and the substantially L-shaped portion of the driven shaft 37 forms a joint portion 36 together with the portion of the output shaft 35 whose cross section is substantially inverted L-shaped. This joint part 36 is connected to the output shaft 35
This is a type of bidirectional joint that can transmit rotation in both forward and reverse directions to the driven shaft 37. A guide tube 38 is attached to the outer periphery of the joint portion 36 to prevent the joint portion 36 from disengaging. 39 is the guide tube 38
A snap spring attached to the driven shaft 37 is shown to prevent it from coming off and falling. The driven shaft 37 is threaded from the middle to the lower part, and the lower end of the driven shaft 37 is connected to a ball screw 40, and the rotation transmitted from the output shaft 35 to the driven shaft 37 is caused by the rotation of the ball screw 40 itself. converted into reciprocating motion. Reference numeral 41 indicates a guide member screwed onto the casing of the ball screw 40, which prevents the ball screw 40 from tilting and smoothly reduces the flux and changes the direction of movement. Further, the valve shaft 26 on the side of the valve means 1 is screwed into the lower part of the guide member 41.
It is prevented from loosening with lock nut 43. Reference numeral 44 denotes a guide rod that prohibits and guides the guide member 41 from rotating, and the lower end of this guide rod 44 is connected to the lid body 2.
0 hole 45 , one upper end is held by a hole 47 of a holding plate 46 , and is sandwiched between the lid body 20 and the mounting cylinder 32 .

Next, a portion forming the valve closed position detecting means 9 will be explained with a partial enlargement shown in FIG. 3. 48 is driven shaft 3
A vertically moving plate is shown attached to the upper part of the ball bearing 5 via the snap spring 39, and a gap 49 is provided above and below this vertically moving plate 48.
0,51 are arranged. As shown in the figure, the bearing 50 receives rotation when the driven shaft 37 moves upward in the valve closed state, while the bearing 51 receives the rotation when the driven shaft 37 moves upward in the valve open state.
When the driven shaft 37 and deceleration mechanism 40 move downward,
etc. subject to gravity. Reference numeral 52 indicates a transmission member placed on the bearing 50, and this member 52 is biased against the bearing 50 using a disc spring 53.
Further, the transmission member 52 is plate-shaped, and the right end portion is attached to the mounting tube 3.
It is located in a groove 54 provided on the top surface of the switch 2 and is bent upward, with the flat part of the bent end facing the micro switch 55. Further, the micro switch 55 is connected to the mounting tube 3 via the mounting plate 56.
Can be attached to 2. 60 is step motor 3
1. A cover is shown attached to the upper end of the mounting tube 32 to cover parts such as a micro switch, and this cover 60 is provided with a wiring insertion opening 61.

The operation of this embodiment will be explained. When an operation signal is sent from the driver 8 to the step motor 31, the step motor 31 rotates the output shaft 35 based on this command. The output shaft 35 transmits this rotation to the driven shaft 37, and the rotation of the driven shaft 37 is converted into vertical movement of the ball screw 40 itself. The vertical movement of this ball screw 40 is controlled by a guide member 41.
The signal is transmitted to the valve shaft 26 via the valve body 2, and the valve shaft 26
2 to change the opening degree of the valve port 13. When the valve is in the closed state as shown in the figure, the valve body 22
comes into contact with the valve seat member 18, so the valve shaft 26 cannot move down any further, and this reaction force is applied to the ball screw 40.
This acts in a direction to push up the driven shaft 37, and the driven shaft 37 begins to move upward. The vertical moving plate 48 is a disc spring 5
As the driven shaft 37 moves upward against the elastic force of 3, the transmission member 52 is lifted up via the bearing 50. The micro switch 55 is the transmission member 52
is switched as the valve rises above a predetermined value, and a valve closing position detection signal is sent to the control means 5.
A signal is sent to the step motor 31 from the step motor 31 to prohibit operation in the valve closing direction. Therefore, even after the valve body 22 is seated on the valve seat member 18, the valve body 22 continues to be driven, and there is no danger that unreasonable force will be applied to the valve body 22, the valve seat member 18, etc., causing damage and deformation of these parts. Here,
The ball screw 40 is connected to the valve stem 2 in the valve closing position.
It has the effect of inhibiting the displacement of 6. In addition, in the valve closing position, a disc spring 53 is interposed in the portion that transmits the rotational force of the output shaft 35 to the valve shaft 26 and is compressed under the load, and as the disc spring 53 is compressed, the micro switch is The transmission member 52 that switches the valve 55 has the function of detecting the force acting on the valve shaft 26 when the valve is in the closed position. In addition, when returning from the valve closed state to the valve open state, the step motor 31
With the operation, the driven shaft 37 is moved downward by the elastic force of the disc spring 53 to a position where the vertical moving plate 48 comes into contact with the bearing 51. After the vertical moving plate 48 comes into contact with the bearing 51, the ball screw 40 itself moves upward, the guide member 41 lifts the valve shaft 26, and the valve shaft 26 drives the valve body 22 in the valve opening direction. to change the opening degree of the valve port 13. Thus, in this embodiment, a small elastic body such as the disc spring 53 that exerts a large elastic force is used, and the transmission member 52 is housed in the groove 54 of the mounting tube 32, so that the part forming the valve closing position detection means 9 is It is effective in reducing the space occupied by the control valve and making the control valve more compact. In addition, mechanical parts such as the screw part of the driven shaft 37, the ball screw 40, and the guide member 41 are arranged inside the mounting tube 32 so that they are not directly exposed to the outside air, so these parts are not susceptible to rust or dirt. This eliminates the risk of malfunction. Furthermore, since the step motor 31 can exert a large output, a reduction mechanism with a small reduction ratio, such as a ball screw 40, can be applied. In addition, the ball screw 40 has almost no crashing compared to other speed reduction mechanisms and moves smoothly, so that the opening/closing valve can be positioned accurately and accurate control can be performed.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a control valve according to an embodiment of the present invention, FIG. 2 is an example diagram embodying only part A in FIG. 1, and FIG. 3 is a partially enlarged view of FIG. 1. 1 is a valve means, 4 is a pressure detection means, 5 is a control means, 6 is an input means, 7 is an operating means, 8 is a driver, 9 is a valve closing position detection means, 10 is a valve body, 11
is an upstream passage, 12 is a downstream passage, 13 is a valve port, 18
20 is a valve seat member, 20 is a lid body, 22 is a valve body, 26 is a valve shaft, 31 is a step motor, 32 is a mounting cylinder, 35
is an output shaft, 36 is a joint, 37 is a driven shaft, 40 is a ball screw, 41 is a guide member, 48 is a vertical moving plate, 50 and 51 are bearings, 52 is a transmission member, 53 is a disc spring, 55 is a micro Switch, 6
0 indicates cover.

Claims (1)

[Claims] 1 The control means receives the target signal and the detection signal of the state of the control system and issues an operation signal, and the operation means receives this operation signal and operates the valve means to open a fluid passage communicating with or from the control system. In a control valve that adjusts the temperature, the rotating shaft of a ball screw is connected to the output shaft of the operating means so that it can receive rotational force and be displaced in the axial direction, and the reciprocating member of the ball screw is connected to the rotating shaft of the valve means. The valve shafts are connected, and the rotating shaft of the ball screw is urged in the valve closing direction of the valve means by an elastic means,
A transmission member is attached to the movable end of the elastic means so as to be displaced with the compressive displacement thereof, and a limit switch that sends a signal to the operating means to stop operation in the valve closing direction is incorporated into the control means, and the transmission member displaces the limit switch by a predetermined amount. The control valve is installed so that it is activated in the specified position.