JPH0821554A - Motor-driven flow control valve - Google Patents

Abstract

PURPOSE:To make accurate rate-of-flow control from the low flow range to the high and make small the whole valve construction by introducing the valve configuration of two step type which consists of the first valve element and second valve element. CONSTITUTION:A motor-driven flow control valve for use in the rate-of-flow control of a refrigerant to serve the refrigerating cycles is embodied as a two-step valve consisting of the first valve element 21 having a small diameter to be operated by a valve opening/closing mechanism C and the second valve element 22 having a large diameter which works interlocking with the motion of the first valve element 21 and is opened in a certain lag from its opening. With actuation of a stepping motor B, first the first valve element 21 moves as apart from the small diametric seat 26 of the second valve element 22 so that the small diametric valve opening 27 of the second valve element 22 is opened. Then the first valve element 21 is engaged by the second valve element 22 by an engaging means 30 with the opening motion of the first valve element 21, and interlocking with the motion of the first valve element 21, the second valve element 22 moves as apart from the large diametric seat 6 of the valve body A so that the large diametric valve opening 5 of the valve body A is opened.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric flow control valve used for controlling the flow rate of a fluid such as a refrigerant used in a refrigeration cycle.

[0002]

2. Description of the Related Art A conventional electric flow control valve is as shown in FIG. 3, in which a first casing 1 is connected to a valve casing 3 having a valve chamber 4 and a fluid inlet 1a and a second passage. 2 is the inlet 1
A valve body A having a large-diameter valve seat 6 provided at a large-diameter valve opening 5 which opens a fluid outlet 1b connected at a position orthogonal to a and communicates with a valve housing valve chamber 4 of the fluid outlet 1b, and this valve. It has a hollow cylindrical can 7 formed of a non-magnetic plate fixed to the outer side of the valve casing on the side opposite to the fluid outlet 1b of the main body A, and a stator coil 8 arranged outside the can 7. A pulse controllable stepping motor B provided with a rotor 9 which is rotated by energization excitation of a stator coil 8 inside a can 7.
And a valve body 10 that opens and closes the valve opening 5 by contacting and separating from the large-diameter valve seat 6 of the valve body A, and the valve body 10 is screw-fed in the valve housing valve chamber 4 by rotation of the rotor of the stepping motor B. And a valve opening / closing mechanism C that moves in the valve opening / closing direction by an action.

The valve opening / closing mechanism C has a male screw portion which is screwed into an inner peripheral female screw portion of the rotor 9, and is screwed and fixed to the valve casing projecting port 3a of the valve body A (the screwing screw portion is caulked). Tubular fixed guide 11 fixed to the rotor 9 and the upper end shaft portion 12a inserted into the fixed guide 11 into the center hole of the upper portion of the rotor and integrated with the rotor 9 by a locking tool 13 such as a C-shaped ring. A valve rod 12 that is locked so as to move, and the valve rod upper end shaft portion 1
The rotor 9 is provided with a valve closing buffer spring 15 which is interposed between the root step portion of 2a and the rotor upper washer 14 and biases the valve rod 12 in the valve closing direction (downward in FIG. 3). The fixed guide 11 moves in the axial direction while rotating by the screw feed action, and the rotor 9 rotates to move the valve rod 1
By moving 2 in the valve opening / closing direction, the valve body 10 (the large-diameter valve body that contacts and separates from the large-diameter valve seat 6) at the lower end of the valve rod is opened / closed to control the flow rate of the fluid. .

Reference numeral 16 in the drawing is screwed to the lower end of the rotor 9 so that the amount of protrusion can be adjusted, and when the valve body 10 is closed, it abuts against the can lower stopper 17 as shown in the drawing. 9 shows a valve closing rod for restricting the valve closing lower limit of the valve 9, and 18 in the figure is screwed to the upper end of the rotor 9 so that the protrusion amount can be adjusted, and the valve body 10 is fully opened (valve body). The valve-opening control rod for contacting the can upper stopper 19 and restricting the valve-opening rising limit of the rotor 9 immediately before the upper surface of 10 hits the upper surface of the valve housing valve chamber 4 is shown.

Thus, the electric flow rate control valve constructed as described above is operated so that the pulse applied to the stator coil 8 can obtain a two-stage fluid flow rate control characteristic as shown in FIG. For example, as shown in FIG. 2, the flow rate control characteristic of this fluid controls a low flow rate range (L part in the figure) between 0 and 250 pulses, and a large flow rate range (H part in the figure) between 250 and 500 pulses. ) Is controlled in two steps.

[0006]

However, in order to satisfy the flow rate control characteristic as shown in FIG. 2 by one valve body 10 and valve seat 6, the diameter of the valve port 5 is set to the maximum flow rate (at the time of 500 pulses). It is necessary to increase according to the flow rate) (large diameter valve opening is required). Therefore, the control of the large flow rate region (H portion in the figure) in FIG. 2 can be precisely performed, but the low flow rate region (L portion in the diagram) in FIG. 2 has a large flow rate due to a slight fluctuation of the stroke of the valve body 10. Therefore, there is a drawback that the flow rate control in the low flow rate region (L portion) varies, and precise flow rate control cannot be performed.

Further, in the conventional flow rate control valve, when the valve is opened, the fluid pressure acts in the direction of pressing the valve body 10 against the valve seat 6, that is, the valve body 10 (pressure difference P before and after the valve body P ) × (valve body diameter D ² × π / 4), a large torque is required to open the valve body 10, so that the winding specification of the stator coil 8 may be increased. However, it is necessary to take measures such as increasing the magnetic flux density of the rotor magnet, which causes a problem that the entire valve becomes large and expensive.

The present invention was devised in order to solve the above-mentioned conventional problems, and its purpose is to enable precise flow rate control from a low flow rate region to a large amount region, and to open the valve for fluid pressure. Another object of the present invention is to provide an electric flow rate control valve that has a small torque and can be downsized as a whole.

[0009]

In order to achieve the above object, in the present invention, a small diameter operated by a valve opening / closing mechanism C is used instead of the valve body 10 in the conventionally known electric flow control valve shown in FIG. A two-stage valve consisting of a first valve body 21 and a large-diameter second valve body 22 that is interlocked with the movement of the first valve body 21 and is opened with a time lag after the opening of the first valve body 21. The valve seat abutment surface 23 for contacting and separating the second valve body 22 with the large-diameter valve seat 6 of the valve body A and the communication hole 2 for the valve housing valve chamber 4 of the valve body A
And a first valve chamber 24 communicating with the first valve chamber 24.
And a small diameter valve opening 27 that communicates the second flow path 2, a small diameter valve seat 26 formed in the valve chamber opening of the small diameter valve opening 27 to and from the first valve body 21, and the first valve body 21. Engaging means 30 with
And the valve seat abutting surface 23 has a large diameter valve seat 6 of the valve body A.
It is characterized in that it is biased by a spring 31 in the direction of being pressed by the valve, and is pulled up by the engaging action of the engaging means 30 when the first valve body 21 is opened to open the valve.

[0010]

According to the electric flow rate control valve having the above-described structure, the operation of the stepping motor B (screw feeding operation by rotor rotation)
Thus, the first valve body 21 first moves in the direction away from the small-diameter valve seat 26 of the second valve body 22 to open the small-diameter valve port 27 of the second valve body 22.

At this time, the second valve body 22 is pressed by the large-diameter valve seat 6 of the valve body A by the spring force of the spring 31 to close the large-diameter valve opening 5 of the valve body A. The fluid flowing from the passage 1 into the valve casing valve chamber 4 passes through the passage of the communication hole 25 of the second valve body 22 → the first valve chamber 24 → the small diameter valve port 27 and the second passage 2
Be leaked to. The flow rate at this time is a small flow rate (low flow rate), and the control of this low flow rate region is performed by opening the small diameter first valve body 21 with respect to the small diameter valve opening 27 (the opening area of the small diameter valve seat 26 and the first valve body 21). ), It is possible to make a slight change in the flow rate with respect to a slight change in the opening stroke of the first valve body 21, so that a precise flow rate that does not vary in the low flow rate region (L part in FIG. 2). It becomes possible to control.

When the first valve body 21 is opened as described above, the opening movement of the first valve body 21 causes the first valve body 21 to move to the first position.
The valve body 21 and the second valve body 22 are engaged with each other by the engaging means 30, and the second valve body 22 is linked to the movement of the first valve body 21 so that the second valve body 22 is moved to the valve body A.
The large-diameter valve opening 5 of the valve main body A is opened by moving in the direction away from the large-diameter valve seat 6 of the valve main body A, so that the fluid flowing from the first flow path 1 into the valve housing valve chamber 4 has a large diameter of the valve main body A. A part of the fluid (fluid that has flowed into the valve housing valve chamber 4) that flows out from the valve opening 5 to the second flow path 2 communicates with the communication hole 25 of the second valve body 22 → the first valve chamber 24.
-> It flows out into the 2nd flow path 2 via the path | route of the small diameter valve opening 27.

The flow rate at this time is a large flow rate, and since the control of this large flow rate area is determined by the opening degree of the large diameter second valve body 22 with respect to the large diameter valve opening 6, the large flow rate area (see FIG. 2). The precise flow rate control of the (H portion) can be performed as in the conventional case.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be specifically described below with reference to FIG. 1. This electric flow rate control valve has a valve body A, a stepping motor B, and a valve opening / closing mechanism C similar to the conventional one. Since the configurations of the valve body A, the stepping motor B, and the valve opening / closing mechanism C are similar to those of the conventional ones, the same parts are designated by the same reference numerals and detailed description thereof will be omitted.

Therefore, in the present invention, the valve housing valve chamber 4 of the valve body A is vertically elongated as shown in FIG. 1, and the valve body 10 is replaced with the valve body 10 in the conventionally known electric flow control valve shown in FIG. The small-diameter first valve body 21 directly operated by the opening / closing mechanism C and the first valve body 21
The structure is a two-stage valve (a plurality of valves) including a large-diameter second valve body 22 that is opened with a time lag after the opening of the first valve body 21 in conjunction with the movement of the valve body 21.

The second valve body 22 is the large-diameter valve seat 6 of the valve body A.
A conical valve seat abutment surface 23 that comes into contact with and separates from the first valve chamber 24 that communicates with the valve housing valve chamber 4 of the valve body A via a communication hole 25,
A small-diameter valve port 27 that connects the first valve chamber 24 and the second flow path 2 with each other.
And the first portion formed in the valve chamber opening of the small diameter valve port 27.
It has a small-diameter valve seat 26 with which the conical surface of the tip of the valve body 21 comes into contact with and separates from it, and an engaging means 30 with the first valve body 21, and the valve seat contact surface 23 is a large-diameter valve seat of the valve body A. It is biased by the compression spring 31 in the direction in which it is pressed against 6.

The second valve body 22 is held by a spring-biased valve holder 28 as shown in the drawing.
The inner peripheral flange portion 29 protruding into the first valve chamber 24 of No. 8 is formed as the engaging means 30 with which the upper protrusion 20 (collar-shaped protrusion) of the first valve body 21 can be engaged, and the first valve body 21 When the valve is opened, the valve body upper protrusion 20 causes the engagement means 30 (valve holder 28
The second valve body 22 is pulled up and opened by engaging with the flange portion 29) of the second valve body 22.

When the stepping motor is operated, the electric flow rate control valve having the above-described structure is so arranged that the first valve body 21 is separated from the small-diameter valve seat 26 of the second valve body 22 by the screw feeding action of the rotor rotation. To open the small-diameter valve opening 27 of the second valve body 22.

At this time, the second valve body 22 is pressed by the large-diameter valve seat 6 of the valve body A by the spring force of the spring 31 to close the large-diameter valve opening 5 of the valve body A, so that the first flow The fluid flowing from the passage 1 into the valve casing valve chamber 4 passes through the passage of the communication hole 25 of the second valve body 22 → the first valve chamber 24 → the small diameter valve port 27 and the second passage 2
Be leaked to. The flow rate at this time is a small flow rate (low flow rate), and the control of this low flow rate region is performed by opening the small diameter first valve body 21 with respect to the small diameter valve opening 27 (the opening area of the small diameter valve seat 26 and the first valve body 21). ), It is possible to make a slight change in the flow rate with respect to a slight change in the opening stroke of the first valve body 21, so that a precise flow rate that does not vary in the low flow rate region (L part in FIG. 2). It becomes possible to control.

When the first valve body 21 is opened as described above, the first valve body 21 moves to open the first valve body.
The valve body 21 and the second valve body 22 are engaged with each other by the engaging means 30, and the second valve body 22 is linked to the movement of the first valve body 21 so that the second valve body 22 is moved to the valve body A.
The large-diameter valve opening 5 of the valve main body A is opened by moving in the direction away from the large-diameter valve seat 6 of the valve main body A, so that the fluid flowing from the first flow path 1 into the valve housing valve chamber 4 has a large diameter of the valve main body A. A part of the fluid (fluid that has flowed into the valve housing valve chamber 4) that flows out from the valve opening 5 to the second flow path 2 communicates with the communication hole 25 of the second valve body 22 → the first valve chamber 24.
-> It flows out into the 2nd flow path 2 via the path | route of the small diameter valve opening 27.

As described above, by making the valve portion structure a two-stage valve (a plurality of valves) by the first valve body 21 having a small diameter and the second valve body 22 having a large diameter, the low flow rate region (L part in FIG. 2) can be obtained. Large flow range (Fig. 2H
The flow rate can be controlled precisely up to the part. Here, the case of the conventional one-stage valve and the case of the two-stage valve of the present invention will be compared.

The opening area S of the valve is defined by the valve stroke L _X ,
Letting the valve body diameter be D and the cone half angle of the valve body (cone half angle of the valve seat contact surface) be θ, S = π · L _X · sin θ (D-L _X · sin θ · cos θ)

[0023] 0～0.72Mm ² the valve opening area for obtaining the flow rate of the L portion of Figure 2, when the valve opening area for obtaining the flow rate of the drawing portion H and 0.72 mm ² ～21Mm ^2, need The specifications of such a valve are as follows: In the case of the conventional one-stage valve D = 5.0mm In the case of the proposed two-stage valve D = 1.3mm (first valve body) D = 5.0mm (second valve body)

The maximum opening area of 0.72 mm ² of the L part is 2
In order to obtain at 50 pulse points, in the case of the conventional one-stage valve θ = 1.7 degrees In the case of the two-stage valve of the present proposal θ = 7.7 degrees

Here, considering the machining tolerance of the valve body diameter D and the conical half angle θ of the valve body, in the case of the conventional one-stage valve, S = 0.72 to 0.81 mm ² (valve opening area tolerance width = 0.
09 mm ² ) In the case of the two-stage valve of the present invention S = 0.72 to 0.75 mm ² (valve opening area tolerance width = 0.
03 mm ² ) As described above, when compared with the same machining accuracy in view of the valve opening area tolerance width, the two-stage valve (invention) is three times more accurate than the one-stage surface (conventional). .

[0026]

As described above, according to the electric flow rate control valve of the present invention, the valve section is a two-stage valve (a plurality of valves) having a first valve body 21 having a small diameter and a second valve body 22 having a large diameter. By doing,
Precise flow rate control can be performed from the low flow rate range (FIG. 2L part) to the large flow rate range (FIG. 2H part). In addition, the first valve body 21
Since the valve opening is small, the torque required to open the valve with respect to the fluid pressure can be small, so that an excellent effect of the invention such as miniaturization of the entire valve can be obtained.

[Brief description of drawings]

FIG. 1 is a central longitudinal sectional view of an electric flow control valve according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a flow rate control characteristic of a fluid by the control valve.

FIG. 3 is a central longitudinal sectional view of a conventional electric flow control valve.

[Explanation of symbols]

A ... Valve body, 1 ... 1st flow path, 1a ... Fluid inflow port, 2 ... 2nd flow path, 2a ... Fluid outflow port, 3 ... Valve casing, 4 ... Valve casing valve chamber,
5 ... Large-diameter valve port, 6 ... Large-diameter valve seat, B ... Stepping motor, 7 ... Can, 8 ... Stator coil, 9 ... Rotor, 1
0 ... Valve body, C ... Ben opening / closing mechanism, 11 ... Fixed guide, 12
... valve rod, 13 ... locking tool, 21 ... first valve body, 22 ... second valve body, 23 ... valve seat abutment surface, 24 ... first valve chamber, 25 ... communication hole, 26 ... small diameter valve seat, 27 ... Small-diameter valve port, 28 ... Valve holder, 29 ... Inner peripheral flange portion of valve holder, 30 ... Engaging means, 31 ... Compression spring.

Claims (2)

[Claims] 1. A valve housing having a valve chamber is provided with a fluid inflow port to which a first flow path is connected and a second flow path to which a fluid outflow port is connected in a position orthogonal to the inflow port, and the fluid outflow port A valve body having a large-diameter valve seat in a large-diameter valve port communicating with the valve housing valve chamber, a can fixed to the outside of the valve housing on the opposite side of the fluid outlet of the valve body, and the outside of the can. A pulse controllable stepping motor having a stator coil arranged therein and having a rotor which is rotated by energization and excitation of the stator coil inside the can, and a stepping motor which comes in contact with and separates from a large-diameter valve seat of the valve body. An electric flow control valve having a valve body that opens and closes, and a valve opening and closing mechanism that moves the valve body in a valve housing valve chamber in a valve opening and closing direction by a screw feed action by rotation of a rotor of the stepping motor, Instead, a small-diameter valve operated by a valve opening / closing mechanism 1
A two-stage valve composed of a valve body and a large-diameter second valve body that is interlocked with the movement of the first valve body and opens with a time lag after the opening of the first valve body is applied. A valve seat abutment surface that contacts and separates the body from a large-diameter valve seat of the valve body, a first valve chamber that communicates with a valve housing valve chamber of the valve body through a communication hole, and the first valve chamber and the second flow A small-diameter valve opening communicating with the passage; a small-diameter valve seat formed in the valve chamber opening of the small-diameter valve opening to contact and separate from the first valve body; and an engaging means for engaging the first valve body, The valve seat abutment surface is biased by a spring in a direction to be pressed against the large-diameter valve seat of the valve body, and is pulled up by the engaging action of the engaging means to open the valve when the first valve body is opened. An electric flow control valve having a configuration. 2. The second valve body is held by a spring-biased valve holder, and an inner peripheral flange portion of the valve holder protruding into the first valve chamber is engageable with an upper protrusion of the first valve body. The electric flow control valve according to claim 1, wherein the electric flow control valve is a combination means.