JP6709926B1 - Motorized valve - Google Patents

Abstract

Provided is a motorized valve capable of large flow rate control and small flow rate control in any flow direction. It has a valve body 2 having a valve chamber 2a, a plurality of ports 3 and 4 connected to the valve body 2 and communicating with each other via the valve chamber 2a, and a valve rod 9 having a tip inserted into the valve chamber 2a. The first valve body 6 opens and closes the opening of the large orifice 5. The small orifice 7 is provided in the first valve body 6, communicates the valve chamber 2a with the first port 3 in which the large orifice 5 is provided, and has an opening smaller than the large orifice 5. The second valve body 8 is provided on the valve rod 9, and opens and closes the small orifice 7 as the valve rod 9 reciprocates in the axial direction. The engagement portions 19 and 20 engage the valve rod 9 and the first valve body 6 with the second valve body 8 opening the small orifice 7.

Description

The present invention relates to an electric valve used in a refrigeration cycle such as an air conditioner and a refrigerator.

In air conditioners, refrigerators, etc., a refrigeration cycle is adopted in which the direction and flow rate of the fluid flowing inside is changed according to the intended function. Depending on the refrigeration cycle, the motor-operated valve is required to have both the controllability at the time of flowing a small flow rate and the reduction of the pressure loss at the time of flowing a large flow rate, and to cope with the forward and reverse bidirectional fluid flows.

For example, in the case of flowing a small flow rate in the forward direction and a large flow rate in the reverse direction, an electric valve using a movable valve seat body that also functions as a float type check valve is known ( For example, see Patent Document 1).

JP, 2013-241958, A

The electric valve using the above-mentioned movable valve seat body has a configuration in which the first port and the second port are connected via the valve chamber, and when the fluid flows in the forward direction, the movable valve seat body is used. The flow rate of the refrigerant passing through the small orifice formed in the valve is controlled by advancing and retracting the valve element.

On the other hand, the side peripheral surface of the movable valve seat is slidably inserted into the valve opening (large orifice) of the valve chamber. An inlet having a diameter larger than that of the small orifice is provided on the side peripheral surface of the movable valve seat, and the movable valve seat slides to connect the second port and the valve chamber via the inlet. Open and close the flow path between them. This allows the fluid to flow in the opposite direction so that pressure loss does not occur.

However, the above motor-operated valve is not suitable for circulating a large flow rate in the forward direction.

The present invention has been proposed in order to solve the above-mentioned problems of the prior art, and when the flow direction of the fluid is a forward flow (the flow direction of the refrigerant toward the valve port in the valve chamber), a small flow rate is obtained. An object of the present invention is to provide an electrically operated valve capable of both control and large flow of low pressure loss.

In order to achieve the above object, the motor-operated valve according to the present invention has the following configuration.
(1) A motor-operated valve for controlling a flow rate by axially reciprocating a valve rod, the valve body having a valve chamber, and a plurality of ports connected to the valve body and communicating with each other through the valve chamber, A valve rod whose tip is inserted into the valve chamber.
(2) A large orifice provided between the valve chamber and one of the ports.
(3) A first valve body that opens and closes the opening of the large orifice.
(4) A small orifice provided in the first valve body, which communicates the valve chamber with a port in which the large orifice is provided and which has an opening smaller than the large orifice.
(5) A second valve body which is provided on the valve rod and which comes into contact with and separates from the small orifice as the valve rod reciprocates in the axial direction.
(6) An engagement portion that engages the valve rod and the first valve body with the second valve body opening the small orifice.
(7) In the state where the valve rod moves further in the opening direction of the small orifice than in the state where the second valve element opens the small orifice, the valve rod and the first valve body form the engaging portion. Upon engagement, the first valve body opens the large orifice.

In the present invention, the following configurations can be adopted.
(1) The first valve body is fitted into the inner periphery of the large orifice, guided by the inner peripheral surface of the large orifice, and reciprocates in the moving direction of the valve rod.
(2) The first valve body is composed of a tubular member coaxial with the valve rod, and the side surface of the tubular member has the large orifice and the valve chamber when the first valve body is opened. An opening that communicates with each other is provided.
(3) The first valve body comprises a tubular member coaxial with the valve rod and a sleeve integrally provided with the tubular member, and the valve rod is provided at one opening of the tubular member. A valve seat for contacting the provided second valve body is provided, the sleeve is provided with the engaging portion for engaging with the valve rod, and a side surface portion is provided with an opening for communicating the small orifice and the valve chamber. Parts are provided.
(4) The first valve body is fitted into the inner periphery of the valve chamber, guided by the inner peripheral surface of the valve chamber, and reciprocates in the moving direction of the valve rod.
(5) A valve seat in which the first valve body is composed of a tubular member coaxial with the valve rod, and the second valve body provided on the valve rod contacts the large orifice side of the tubular member. Is provided, the engaging portion that engages with the valve rod is provided on a side of the tubular member opposite to the large orifice, and an opening that connects the small orifice and the valve chamber is provided on a side surface portion of the tubular member. Parts are provided.

According to the present invention, it is possible to provide an electrically operated valve capable of both small flow rate control and large flow rate flow with low pressure loss when the small flow rate and the large flow rate are in the same direction.

It is sectional drawing which shows the structure of the motor operated valve of 1st Embodiment. FIG. 3 is an enlarged cross-sectional view showing the configuration of the motor-operated valve according to the first embodiment, showing a state in which the valve body is inserted all the way into the small orifice. It is an expanded sectional view showing composition of an electrically operated valve of a 1st embodiment, and shows a state where an opening made contact with a ring and a top plate. It is an expanded sectional view showing composition of an electrically operated valve of a 1st embodiment, and shows a state where a valve room and the 1st port were open for free passage via a large orifice. It is sectional drawing which shows the structure of the motor operated valve of 2nd Embodiment. It is an expanded sectional view which shows the structure of the electrically operated valve of 2nd Embodiment, and shows the state in which the valve main body was inserted to the innermost part of the small orifice. It is an expanded sectional view which shows the structure of the motor-operated valve of 2nd Embodiment, and shows the state which the opening and the top plate contacted. It is an expanded sectional view showing composition of an electrically operated valve of a 2nd embodiment, and shows a state where a valve room and the 1st port were open for free passage via a large orifice. 5 shows a flow rate characteristic of the electric valve according to the embodiment of the present invention. Figure 6 shows a motorized valve in which the small orifice does not close completely. 6 is a flow characteristic of the motor-operated valve in which the small orifice is not completely closed according to the embodiment of the present invention. It is sectional drawing which shows the structure of the motor operated valve of 3rd Embodiment. It is an expanded sectional view which shows the structure of the electrically operated valve of 3rd Embodiment, and shows the state in which the valve main body was inserted to the innermost part of the small orifice. It is an expanded sectional view which shows the structure of the electrically operated valve of 3rd Embodiment, and shows the state which the opening and the top plate contacted. It is an expanded sectional view showing composition of an electrically operated valve of a 3rd embodiment, and shows a state where a valve room and the 1st port were open for free passage via a large orifice.

[1. First Embodiment]
Hereinafter, embodiments of a motor-operated valve according to the present invention will be described in detail with reference to the drawings. FIG. 1 is a cross-sectional view showing the configuration of the motor-operated valve according to this embodiment. However, the stator and coil of the stepping motor provided outside the cylindrical member 1 are omitted. In FIG. 1, with respect to the central axis of the cylindrical member 1, the valve body 2 side is upward and the first port 3 side is downward.

[1-1. Schematic configuration]
As shown in FIG. 1 and FIG. 2, in the motor-operated valve of the present embodiment, each of the first port 3 and the second port 4 which is a path of a fluid such as a refrigerant is connected to the valve chamber 2a and the valve chamber 2a is interposed therebetween. The first port 3 and the second port 4 communicate with each other. A large orifice 5 is installed at the bottom of the valve chamber 2a. The large orifice 5 has a circular opening, and the radius of the hole is the same as that of the opening even when the opening changes from the opening to the depth direction of the hole. The first valve body 6 is slidably inserted into the large orifice 5. The first valve body 6 is provided with a small orifice 7.

The second valve body 8 is housed in the valve chamber 2a. The second valve body 8 is formed at the tip of a valve rod 9 that is movable in the axial direction. The second valve body 8 tapers toward the inner diameter of the small orifice 7, and the waist circumference differs depending on the height from the tip. The valve rod 9 is driven by a stepping motor as a drive source, and axially moves toward or away from the small orifice 7 by a screw feeding mechanism. As a result, the amount of insertion of the second valve body 8 into the small orifice 7 becomes variable, and the flow rate between the first port 3 and the second port 4 is controlled according to the amount of insertion.

Such a motor-operated valve is configured by stacking the cylindrical member 1 and the valve body 2 on top of each other. The cylindrical member 1 is also called a can, and is made of, for example, a non-magnetic metal plate such as stainless steel, and has a cup shape with one end surface closed in a hemisphere shape. The valve body 2 is also called a valve body, is a substantially cylindrical body having an internal space, and has an opening at one end surface. The cylindrical member 1 and the valve body 2 are overlapped with each other with the opening of the cylindrical member 1 and the valve body 2 aligned. The cylindrical member 1 is an airtight container that houses a moving mechanism of the valve rod 9 including a screw feeding mechanism.

The first port 3 is connected to the end face of the valve body 2 facing the cylindrical member 1 and opposite to the opening, communicates with the valve chamber 2 a, and extends coaxially with the central axis of the cylindrical member 1. The second port 4 is connected to the side peripheral surface of the valve body 2, communicates with the valve chamber 2 a, and extends orthogonal to the extending direction of the first port 3. The large orifice 5 is installed on the open end surface of the first port 3.

The valve rod 9 is arranged coaxially with the central axis of the cylindrical member 1 and has a rod shape. The valve rod 9 projects from the inside of the cylindrical member 1 into the valve chamber 2 a through the opening of the cylindrical member 1 and the opening of the valve body 2. A guide member 2b is arranged in the opening of the cylindrical member 1 and the opening of the valve body 2. The valve rod 9 is restricted from moving in the radial direction by the guide hole of the guide member 2b, and is guided in the vertical direction. The valve rod 9 moves in a direction in which the tip thereof comes into contact with and separates from the small orifice 7 provided in the first valve body 6. The second valve body 8 is formed at the tip of the valve rod 9 that reaches the small orifice 7. The second valve body 8 is formed by reducing the diameter of the valve rod 9 toward the tip.

The valve rod 9 is supported by a guide bush 11 arranged on the cylindrical member 1 so as to be rotatable and movable up and down except for both end regions. The guide bush 11 supports the circumferential surface of the valve rod 9 along the axial direction. A fixing screw 11 a, which is a male screw, is formed on the outer periphery of the guide bush 11. A valve rod holder 12 arranged in the cylindrical member 1 is screwed onto the outer periphery of the guide bush 11. That is, the valve rod holder 12 is a cylindrical body having a perforated ceiling portion 12a on the end surface of the cylindrical member 1 on the bottom side, and the movable screw 10 which is a female screw is formed on the inner periphery of the valve rod holder 12. ing. The fixing screw 11a of the guide bush 11 and the movable screw 10 of the valve rod holder 12 are screwed together to form a screw feed mechanism.

A rotor 13 of a stepping motor is coaxially provided on the outer circumference of the valve rod holder 12. The rotor 13 is made of, for example, a rare earth plastic magnet such as Nd-Fe-B system, has a cylindrical shape with a predetermined magnetic pole, and has a support body 14 supporting the valve rod holder 12 extending on its inner peripheral surface. It is set up. The support 14 fixes the rotor 13 and the valve rod holder 12 to each other.

The rear end of the valve rod 9 toward the bottomed portion of the cylindrical member 1 projects from the opening of the ceiling portion 12 a of the valve rod holder 12. A push nut 15 is fixed to the protruding portion by means such as press fitting or welding. The valve rod 9 has a stepped portion 9a with a stepwise narrower diameter from the portion arranged in the valve rod holder 12 to the rear end, and between the stepped portion 9a and the ceiling portion 12a of the valve rod holder 12. A compression coil spring 16 fitted in the valve rod 9 is installed therein.

The compression coil spring 16 biases the tip end side of the valve rod holder 12 toward the first port 3 side. Therefore, the ceiling 12a of the valve rod holder 12 is elastically sandwiched by the compression coil spring 16 and the push nut 15, and the valve rod holder 12, the push nut 15, and the valve rod 9 fixed to the rotor 13 are integrated with the rotor 13. Move to.

A return spring 17 is fitted on the outer circumference of the push nut 15. When the valve rod 9 moves to the bottomed side of the cylindrical member 1, the return spring 17 comes into contact with the bottomed portion of the cylindrical member 1 and is compressed. The movable screw 10 of 12 and the fixing screw 11a of the guide bush 11 are urged in a direction to engage with each other.

A lower stopper 18 is fixed below the portion of the guide bush 11 into which the valve rod holder 12 is fitted. The lower stopper 18 is fixed to the guide bush 11 by, for example, insert molding or screwing into the fixing screw 11a. A stopper 9c (upper stopper) is integrally provided on the lower portion of the valve rod holder 12. The stopper 9c contacts the lower stopper 18 when the valve rod holder 12 reaches the lowermost position, and restricts further rotation and lowering of the valve rod holder 12.

In such a motor-operated valve, a pulse signal from the outside is input to the stepping motor to rotate the rotor 13. The amount of rotation of the rotor 13 is proportional to the number of pulses. Due to the structure using the compression coil spring 16 and the push nut 15, the valve rod holder 12 also axially rotates around the guide bush 11 as the rotor 13 rotates. As a result, the valve rod 9 also moves in the axial direction while being supported by the guide bush 11.

[1-2. Structure of valve part]
FIG. 2 is an enlarged cross-sectional view showing the configuration of the valve portion of this embodiment. In this embodiment, a large orifice 5 is provided between the valve chamber 2a and the first port 3. The large orifice 5 is provided with a first valve body 6 that opens and closes its opening. The first valve body 6 is composed of a tubular member 62 coaxial with the valve rod 9 and a sleeve 63 provided integrally with the tubular member 62. The side surface of the tubular member 62 is provided with an opening 62a that connects the large orifice 5 and the valve chamber 2a when the first valve body 6 is opened. The tubular member 62 is fitted into the inner circumference of the large orifice 5, is guided by the inner peripheral surface of the large orifice 5, and moves back and forth in the vertical direction (axial direction).

The first valve body 6 is provided with a small orifice 7 which communicates the first port 3 provided with the large orifice 5 with the valve chamber 2 a and which has a smaller opening than the large orifice 5. The valve rod 9 is provided with a second valve body 8 that moves back and forth in a direction toward and away from the small orifice 7 as the valve rod 9 reciprocates in the axial direction. On the sleeve 63 side of the small orifice 7 provided in the first valve body 6, a valve seat with which the second valve body 8 provided in the valve rod 9 contacts is provided. On the other hand, an opening 63a that connects the small orifice 7 and the valve chamber 2a is provided on the side surface of the sleeve 63 of the first valve body 6.

The valve rod 9 and the first valve body 6 are provided with an engagement portion that engages the second valve body 8 with the second valve body 8 in the state where the small orifice 7 is opened. This engaging portion is, for example, a ring 19 fixed around the valve rod 9 and a protrusion 20 provided on the sleeve 63 of the first valve body 6.

In the present embodiment, the positional relationship among the first valve body 6, the second valve body 8 and the engaging portion is configured as follows. That is, when the second valve body 8 closes the small orifice 7, the first valve body 6 closes the large orifice 5. When the flow direction of the refrigerant is the forward direction, the first valve body 6 is pressed against the valve seat of the large orifice 5 by the fluid pressure difference even when the second valve body 8 does not close the small orifice 7. .. On the other hand, the second valve body 8 of the valve rod 9 is moved in the opening direction of the small orifice 7, and the ring 19 of the valve rod 9 is moved further in the opening direction than the position where the ring 19 of the valve rod 9 is engaged with the protrusion 20 of the first valve body 6. When moved, the first valve body 6 separates from the large orifice 5 and the large orifice 5 is opened.

[1-3. Action]
In the motor-operated valve having the above configuration, the flow rate is controlled by reciprocating the valve rod 9 in its axial direction. Hereinafter, the flow rate control in the present embodiment will be described with reference to FIGS.

At the time of small flow rate control, from the position where the second valve body 8 closes the small orifice 7 (FIG. 2) to the position where the ring 19 of the valve rod 9 contacts the protrusion 20 of the sleeve 63 (FIG. 3), The rod 9 is moved up and down. That is, when the valve rod 9 is at the lowest position, the second valve body 8 is inserted to the deepest position of the small orifice 7. As a result, the gap between the second valve body 8 and the small orifice 7 is eliminated, and the fluid does not pass through the small orifice 7. It should be noted that, at the lower end position of the second valve body 8, the small orifice may not be completely closed, that is, it may be set so as to secure a minute flow rate in the forward direction. When increasing the amount of fluid passing through the small orifice 7, the valve rod 9 is moved upward in the figure (the direction in which the second valve body 8 is separated from the small orifice 7). The gap between the second valve body 8 and the small orifice 7 increases with the amount of upward movement of the second valve body 8. That is, when it is desired to increase the flow rate, the valve rod 9 is moved upward. For example, when it is desired to obtain the maximum flow rate in the control range of the small flow rate control, the valve rod 9 is raised until the ring 19 of the valve rod 9 comes into contact with the protrusion 20 of the sleeve 63, as shown in FIG. On the other hand, when it is desired to reduce the flow rate, the valve rod 9 is moved downward.

On the other hand, during the large flow rate control, as shown in FIG. 4, the opening 62a provided in the first valve body 6 is moved upward in the drawing to a position where it is not blocked by the inner peripheral surface of the large orifice 5. That is, when the valve rod 9 moves from the position shown in FIG. 3 to the position shown in FIG. 4, as the valve rod 9 rises, the ring 19 and the protrusion 20 of the sleeve 63 engage with each other, so that the first valve body 6 moves. Move up. At this time, the tubular member 62 of the first valve body 6 is guided by the inner circumference of the large orifice 5 and moves vertically without rattling. At the position where the valve rod 9 has moved to the uppermost position (upper end position), the opening 62a provided in the tubular member 62 is located outside the large orifice 5, that is, inside the valve chamber 2a. The fluid flows between the valve chamber 2a and the large orifice 5 via the opening 62a. At the upper end position of the valve rod 9, a part of the tubular member 62 is arranged inside the large orifice 5.

When the valve rod 9 moves in the valve opening direction, the range from the lower end position until the ring 19 locks the protrusion 20 is the flow rate control range of the small flow rate (the range in which the refrigerant passes only the small orifice 7). 19 is a flow rate control range of the large flow rate from the position where the protrusion 20 is locked to the upper end position (the range in which the refrigerant passes through the small orifice 7 and the large orifice 5). Here, when the axial movement range (movement range from the lower end position to the upper end position) of the valve rod 9 of the motor-operated valve is represented by the number of control pulses of the stepping motor, the motor-operated valve according to the present embodiment moves the valve rod 9. The range is 0-500 pulses. Among these, the flow rate control range of the small flow rate is a range of 0 to 150 (±50) pulses, and the range of 150 (±50) to 500 pulses is set to be the flow rate control range of the large flow rate. In other words, the ratio of the axial length of the flow rate control range of the small flow rate to the large flow rate is set to 2:8 to 4:6. The maximum passage amount of the refrigerant in the large flow rate control range is 10 times or more the maximum passage amount of the refrigerant in the small flow rate control range.

[1-4. effect]
The motor-operated valve of this embodiment can achieve the following effects.

(1) A large orifice 5 and a smaller orifice 7 having a smaller diameter are provided between the valve chamber 2a and the first port 3, and these are opened and closed by the first valve body 6 and the second valve body 8, respectively. Therefore, it is possible to control a large flow rate and a small flow rate.

(2) When a fluid flows from the first port 3 to the second port 4, the first valve body 6 that opens and closes the large orifice 5 is pressed by the second valve body 8 provided on the valve rod 9. As a result, the large orifice 5 can be closed against the pressure of the fluid flowing from the first port 3. On the contrary, when the fluid is allowed to flow from the second port 4 to the first port 3, the ring 19 and the protrusion 20 are engaged with each other so that the first valve body 6 that opens and closes the large orifice 5 is enlarged by the valve rod 9. It can be pulled up from within the orifice 5. As a result, the large orifice 5 can be opened against the pressure of the fluid flowing from the second port 4. As a result, a large flow rate control and a small flow rate control are possible for the fluid flowing in either direction.

(3) Since (the tubular member 62 of) the first valve body 6 is slidably fitted into the inner periphery of the large orifice 5, the first valve body 6 moves up and down in conjunction with the valve rod 9. There is no rattling when performing, and it is possible to perform the opening/closing operation of the first valve body 6 with high accuracy.

(4) Since the first valve body 6 is composed of the tubular member 62 coaxial with the valve rod 9 and the sleeve 63 provided integrally with the tubular member 62, the interior of these members is filled with the flow path and the valve. It can be used as a location for disposing the rod 9, and a lightweight and miniaturized electric valve can be obtained.

(5) In the present embodiment, the protrusion 20 that comes into contact with the ring 19 is provided on the sleeve 63 as an engaging portion between the valve rod 9 and the first valve body 6. Thereby, the motor-operated valve can be manufactured by relatively easy processing, and the engaging portion having high strength can be manufactured. The engaging portion may be a member other than the ring and the protrusion. For example, it may be a step portion formed by enlarging at least a part of the outer peripheral surface of the valve rod 9 perpendicularly to the axial direction. Thereby, the valve opening/closing portion can be manufactured by simple processing.

[2. Second Embodiment]
[2-1. Constitution]
The second embodiment will be described with reference to FIGS. In the second embodiment, the first valve body 6A is composed of one tubular member whose upper part is closed by the top plate and whose lower part is closed by the bottom plate. The tubular member has a large diameter in the upper portion and a small diameter in the lower portion, and the outer circumference of the large diameter portion is guided to the inner peripheral surface of the valve chamber 2a and reciprocates in the valve chamber 2a together with the valve rod 9. The gap between the outer periphery of the small diameter portion and the inner peripheral surface of the valve chamber 2a serves as a flow path that connects the large orifice 5 to the valve chamber 2a and the second port 4.

The small orifice 7 provided on the bottom plate of the first valve body 6A is provided with a valve seat 64 with which the second valve body 8 provided on the valve rod 9 contacts. A protrusion 20 that engages with the ring 19 of the valve rod 9 is provided on the top plate of the first valve body 6A. An opening 63a is provided on the side surface of the small diameter portion of the first valve body 6A so that the small orifice 7 communicates with the valve chamber 2a.

[2-2. Action]
FIG. 6 is an enlarged cross-sectional view showing the structure of the valve portion of this embodiment. In FIG. 6, the valve rod 9 is located at the lowest position. That is, the second valve body 8 is inserted into the small orifice 7 to the innermost position, and the small orifice 7 is closed by the second valve body 8. As a result, the fluid cannot flow between the second valve body 8 and the small orifice 7. Further, since the opening of the large orifice 5 on the valve chamber 2a side is closed by the small diameter portion of the first valve body 6, the fluid cannot flow between the large orifice 5 and the first valve body 6. It should be noted that, at the lower end position of the second valve body 8, the small orifice may not be completely closed, that is, it may be set so as to secure a minute flow rate in the forward direction.

At the time of the small flow rate control, from the position where the second valve body 8 closes the small orifice 7 of the valve rod 9 (FIG. 6) to when the ring 19 of the valve rod 9 comes into contact with the top plate portion of the first valve body 6. Move up and down in the interval (Fig. 7). The relationship between the second valve body 8 and the small orifice 7 in this flow rate control is the same as in the first embodiment.

As shown in FIG. 8, during the large flow rate control, the valve rod 9 is moved further upward in the drawing from the position where the small orifice 7 is opened. Then, as the valve rod 9 rises, the ring 19 and the protrusion 20 engage with each other, the valve rod 9 pulls up the first valve body 6, and a gap is created between the first valve body 6 and the large orifice 5. , The large orifice 5 is opened.

FIG. 9 shows the flow rate characteristic of the present motorized valve achieved by the above operation. The state A plotted on the graph of FIG. 9 is the state in which the motor-operated valve is in the lower left of FIG. 9 and the state shown in FIG. 6, and the valve rod 9 is in the lower end position. The state B plotted on the graph of FIG. 9 is a state in which the motor-operated valve is in the middle and lower portions of FIG. 9 and the state shown in FIG. 7, and the ring 19 is in contact with the protrusion 20. A state C plotted on the graph of FIG. 9 is a state in which the motor-operated valve is in the lower right of FIG. 9 and the state shown in FIG. 8, and the valve rod 9 is in the upper end position.

As shown in FIG. 9, when the valve rod 9 moves in the valve opening direction, the valve rod 9 moves from the lower end position in the valve opening direction until the ring 19 contacts the protrusion 20, that is, from state A to state B. The range of is a flow rate control range of small flow rate. In the flow rate control range of a small flow rate, the refrigerant passes only the small orifice 7. Further, when the valve rod 9 moves in the valve opening direction, the flow control range of the large flow amount is from the time when the ring 19 contacts the protrusion 20 to the time when the valve rod 9 is at the upper end position, that is, the range from the state B to the state C. Is. In the large flow rate control range, the refrigerant passes through the small orifice 7 and the large orifice 5.

The range of movement of the valve rod 9 of the motor-operated valve from the lower end position of the state A to the upper end position of the state C through the state B along the axial direction is represented by the number of control pulses of the stepping motor. In the motor-operated valve, the moving range of the valve rod 9 is 0 to 500 pulses. Of these, the flow rate control range of the small flow rate from state A to state B is a range of 0 to 150 (±50) pulses, and the flow rate control range of the large flow rate from state B to state C is 150 (±50) to The range is set to 500 pulses. In other words, the ratio of the length in the axial direction of the flow rate control range of the small flow rate and the large flow rate is set to 2:8 to 4:6. The maximum passage amount of the refrigerant in the large flow rate control range is 10 times or more the maximum passage amount of the refrigerant in the small flow rate control range.

Also in the motor-operated valve of the present embodiment, the small orifice 7 may not be completely closed in the state where the second valve body 8 is located at the lower end position, that is, it may be set so as to secure a minute positive flow rate. FIG. 10 shows a motor-operated valve in which the small orifice 7 is not completely closed, and is a partially enlarged view centering on the second valve body 8. As shown in FIG. 10, the second valve body 8A has a shape in which, from the upper side to the lower side, a cylindrical portion 8c whose diameter does not change and then a tapered portion 8d whose diameter gradually decreases are connected. The inner peripheral shape of the valve opening of the small orifice 7A is a cylindrical portion 7c whose diameter does not change. The inner diameter of the cylindrical portion 7c of the small orifice 7A is larger than the outer diameter of the cylindrical portion 8c of the second valve body 8A.

FIG. 11 shows the flow rate characteristics of the electric valve having the second valve body 8A and the small orifice 7A. As shown in FIG. 11, in the state A in which the valve rod 9 shown in the lower left of FIG. 11 is at the lower end position, the lower portion of the cylindrical portion 8c of the second valve body 8A is located inside the cylindrical portion 7c of the small orifice 7A. The upper portion of the cylindrical portion 8c of the second valve body 8A is exposed from the cylindrical portion 7c of the small orifice 7A. Therefore, a slight gap is formed between the second valve body 8A and the small orifice 7A. Therefore, even in the state A, the flow rate according to the gap flows.

Further, between the state A and the state B, there is an inflection point at the position (control pulse number) of the second valve body 8A corresponding to the boundary position between the cylindrical portion 8c and the tapered portion 8d of the second valve body 8A. Occurs. That is, when the valve rod 9 is raised from the state A, the lower end of the cylindrical portion 8c of the second valve body 8A (the upper end of the taper portion 8d) moves from the state A to the upper end of the cylindrical portion 7c of the valve orifice of the small orifice 7A. The flow rate is constant up to the position, and when the flow rate is further raised from there, the flow rate gradually increases to the state B because the gap expands as the diameter of the tapered portion 8d increases. The state B to the state C have the same flow rate characteristics as in FIG.

[2-3. effect]
Also in the motor-operated valve of the second embodiment, the valve rod 9 can drive the first valve body 6 in both the opening direction and the closing direction. As a result, similar to the first embodiment, it is possible to control the large flow rate and the small flow rate regardless of the flow direction of the fluid. Further, as compared with the first embodiment, the opening of the large orifice 5 can be opened and closed by moving the valve rod 9 by a smaller distance. Further, when the valve rod 9 moves, the first valve body 6 slides on the inner peripheral surface of the valve chamber 2a. As a result, the first valve body 6 can be moved with high precision, the axial length of the large orifice 5 can be shortened, and the electric valve can be downsized.

[3. Third Embodiment]
[3-1. Constitution]
A third embodiment will be described with reference to FIGS. In the third embodiment, the same components as those in the first or second embodiment are designated by the same reference numerals and detailed description thereof will be omitted.

As shown in FIG. 12, in the electrically operated valve of the third embodiment, the valve body 2A is configured by integrally combining the holder 2c, the pipe 2d and the seat member 2e. Further, the first valve body 6B is configured by integrally combining the bottom plate member 62A and the sleeve 63. Although omitted in FIGS. 1 and 5, in the motor-operated valves of the first to third embodiments, a stator unit 65 having a stator of a stepping motor, a coil, and the like provided outside the cylindrical member 1 is externally inserted. And is fixed to the side surface of the valve body 2A with a pin 66.

The holder 2c of the valve body 2A is connected to the cylindrical member 1 by welding the circular edge of the holder 2c to the cylindrical member 1. The guide bush 11 is press-fitted into the upper opening of the holder 2c. The inner peripheral diameter of the lower end side of the holder 2c is equal to or slightly larger than the outer peripheral diameter of the sleeve 63 of the first valve body 6B, and the outer peripheral portion of the sleeve 63 is guided by the inner peripheral surface 2f of the holder 2c. As a result, the first valve body 6B having the sleeve 63 can move up and down along the axis of the valve rod 9, while the movement of the first valve body 6B is restricted in the radial direction of the axis of the valve rod 9.

The pipe 2d is connected to the holder 2c by fitting the lower end of the holder 2c into the pipe 2d and welding it. The second port 4 is connected to the peripheral surface of the pipe 2d. By using this pipe 2d as a part of the valve body 2A, the cost of the valve body 2A can be reduced.

The upper portion of the sheet member 2e is fitted into the lower end of the pipe 2d and is brazed to be connected to the pipe 2d. The first port 3 is connected to the lower end of the seat member 2e by brazing. The inner diameter of the seat member 2e is a multi-step shape having two steps. That is, the upper end opening of the seat member 2e serves as a valve seat for the first valve body 6B, and the large orifice 5 extends from the upper end opening edge of the seat member 2e. The inner diameter of the large orifice 5 is larger than the opening diameter of the first port 3. Then, below this large orifice 5, a step portion having the same inner diameter as the inner diameter of the first port 3 bulges toward the axial center. The end of the first port 3 is abutted against this step and connected by brazing.

The bottom plate member 62A of the first valve body 6B has a small orifice 7 inside. The bottom plate member 62A is press-fitted into the sleeve 63 at the upper end to be integrated. A valve opening 62b reaching the small orifice 7 is formed on the end surface of the bottom plate member 62A on the first port 3 side. The valve port 62b has a taper shape with a diameter enlarged toward the first port 3 side.

In such an electrically operated valve, the first port 3, the second port 4, the pipe 2d and the seat member 2e are brazed. On the other hand, the valve shaft 9 is inserted into the sleeve 63, the ring 19 is press-fitted and fixed to the valve shaft 9, and the bottom plate member 62A is press-fitted into the sleeve 63. Next, the guide bush 11 is press-fitted into the holder 2c, the valve shaft 9 to which the first valve body 6B is connected is inserted into the holder 2c and the guide bush 11, and the rotor 13 and the valve rod holder 12 are assembled. Then, the holder 2c and the pipe 2d are welded. Finally, the starter unit 65 is extrapolated to the cylindrical member 1. As a result, the electric valve is assembled.

[3-2. Action]
FIG. 13 is an enlarged cross-sectional view showing the structure of the valve portion of this embodiment. In FIG. 13, the valve rod 9 is located at the lowest position. That is, the second valve body 8 is inserted into the small orifice 7 to the innermost position, and the small orifice 7 is closed by the second valve body 8. As a result, the fluid cannot flow between the second valve body 8 and the small orifice 7. Further, since the opening of the large orifice 5 on the valve chamber 2a side is closed by the bottom plate member 62A of the first valve body 6B, the fluid cannot flow between the large orifice 5 and the first valve body 6B. It should be noted that at the lower end position of the second valve body 8, the small orifice 7 may not be completely closed, that is, it may be set so as to secure a minute flow rate in the forward direction.

During the small flow rate control, the valve rod 9 is moved from the position where the second valve body 8 closes the small orifice 7 (FIG. 13) until the ring 19 of the valve rod 9 comes into contact with the projection 20 of the first valve body 6B. Move up and down with (Fig. 14). The relationship between the second valve body 8 and the small orifice 7 in this flow rate control is the same as in the first and second embodiments. However, during this small flow rate control, the fluid passes through the tapered valve opening 62b, so that the sound when the fluid passes is reduced.

As shown in FIG. 15, during the large flow rate control, the valve rod 9 is moved further upward in the drawing from the position where the small orifice 7 is opened. Then, as the valve rod 9 rises, the ring 19 and the protrusion 20 engage with each other, the valve rod 9 pulls up the first valve body 6B, and a gap is generated between the first valve body 6B and the large orifice 5. , The large orifice 5 is opened. At this time, since the inner diameter of the large orifice 5 is larger than the opening diameter of the first port 3 due to the seat member 2e having the two-stage multi-stage shape, the maximum flow rate of the fluid is increased.

[3-3. effect]
Also in the electrically operated valve of the third embodiment, the valve rod 9 can drive the first valve body 6B in both the opening direction and the closing direction. As a result, similar to the first and second embodiments, it is possible to perform flow rate control of a large flow rate and a small flow rate regardless of the flow direction of the fluid. In the electrically operated valve of the third embodiment, first, the valve body 2A is partially configured by the pipe 2d, so that the manufacturing cost is reduced. Secondly, since the valve opening 62b reaching the small orifice 7 has a tapered shape, the passage noise of the fluid is reduced, and the electric valve is made silent. Thirdly, since the inner diameter of the large orifice 5 is larger than the opening diameter of the first port 3, the maximum flow rate is increased.

Although the embodiments of the present invention have been described above, various omissions, replacements, and changes can be made without departing from the spirit of the invention. The embodiments and modifications thereof are included in the scope and the gist of the invention, and are also included in the invention described in the claims and the scope equivalent thereto.

DESCRIPTION OF SYMBOLS 1... Cylindrical member 2, 2A... Valve main body 2a... Valve chamber 2b... Guide member 2c... Holder 2d... Pipe 2e... Seat member 2f... Inner peripheral surface 3... 1st port 4... 2nd port 5... Large orifice 6, 6A , 6B... First valve body 7, 7A... Small orifice 7c... Cylindrical portion 8, 8A... Second valve body 8c... Cylindrical portion 8d... Tapered portion 9... Valve rod 9a... Step portion 9c... Stopper 10... Movable screw 11... Guide bush 12... Valve rod holder 12a... Ceiling part 13... Rotor 14... Support 15... Push nut 18... Lower stopper 19... Ring (engaging part)
20... Protrusion 62... Cylindrical member 62A... Bottom plate member 62a... Opening 62b... Valve opening 63... Sleeve 63a... Opening 64... Valve seat 65... Stator unit 66... Pin

Claims (3)

A motor-operated valve that controls the flow rate by reciprocating the valve rod in the axial direction,
A valve body having a valve chamber, a plurality of ports connected to the valve body and communicating with each other through the valve chamber, and a valve rod having a tip inserted into the valve chamber,
A large orifice provided between the valve chamber and one of the ports,
A first valve body that opens and closes the opening of the large orifice;
A small orifice provided in the first valve body, which communicates the valve chamber with a port provided with the large orifice, and which has a smaller opening than the large orifice;
A second valve body that is provided on the valve rod and moves in a direction toward or away from the small orifice with axial reciprocation of the valve rod;
An engaging portion that engages the valve rod and the first valve body with the second valve body opening the small orifice;
Equipped with
The valve body is
A holder for guiding the first valve body on the inner peripheral surface,
A pipe fitted and fixed to the lower end of the holder,
A sheet member fitted and fixed to the lower end of the pipe;
Have
The large orifice is provided in the seat member,
The first valve body has a sleeve in which the outer peripheral portion is guided by the inner peripheral surface of the holder and the engaging portion is provided,
When the valve rod moves further in the opening direction of the small orifice than when the second valve body opens the small orifice, the valve rod and the first valve body engage with the engaging portion. In combination, the first valve body opens the large orifice,
The electrically operated valve, wherein the second valve body does not completely close the small orifice so as to secure a minute flow rate at the lower end position of the second valve body. The valve rod has a small diameter portion having a diameter that can be inserted into an opening provided in the ceiling portion of the sleeve and a large diameter portion having a diameter that cannot be inserted into the opening provided in the ceiling portion of the sleeve. ,
The engagement portion has a ring fixed to the small diameter portion of the valve rod, and a ceiling portion of the sleeve,
The axial length from the ceiling portion to the upper end of the small orifice is shorter than the axial length from the step portion serving as the boundary between the small diameter portion and the large diameter portion to the tip of the second valve body. The motor operated valve according to claim 1. A can that is connected to the valve body and accommodates the screw feed mechanism of the valve rod;
The motor-operated valve according to claim 1, further comprising a stator of a stepping motor outside the can.

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