Electric drive valve

Abstract

To reduce an amount of valve leakage by making a soft material usable for a main valve body.SOLUTION: An electric drive valve includes a main valve, a pilot valve and a pilot valve driving device. The main valve has a valve body 12 having a main valve chamber 13, a main valve port 14, an inflow hole 16 and an outflow hole 17, a main valve body 18, and a valve closing spring 25 for energizing the main valve body toward the main valve port. The pilot valve is a drive valve having a pilot valve chamber 26, a pilot flow passage 30 communicating between the pilot valve chamber and the outflow hole, a pilot valve seat 31 and a pilot valve body 32, and includes a connection member 33 that blocks a main valve chamber top surface. The pilot valve chamber has a first pilot chamber 27 formed on an upper surface side of the connection member, and a second pilot chamber 28 formed on a lower surface side of the connection member. The pilot valve seat and the pilot valve body are arranged in the first pilot chamber. The main valve port is open to a bottom surface of the main valve chamber, and the outflow port is open to a lateral surface of the main valve chamber. The electric drive valve has a communication passage 29 communicating between the two pilot chambers, and an introduction passage 20 communicating between the inflow hole and the second pilot chamber.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an electric drive valve for opening and closing a refrigerant flow path, and particularly to a pilot type drive valve provided with a pilot valve for controlling a main valve.

Background Art

[0002] Electromagnetic valves and electric valves that open and close a refrigerant flow path using an electric drive device such as an electromagnetic actuator or an electric motor have been conventionally used in refrigeration cycle devices equipped with a refrigerant circuit such as an air conditioner, a refrigerating device, and a freezing device.

[0003] Such electric drive valves include a normally closed type (normally closed) that opens only when energized and a normally open type (normally open) that closes only when energized. Further, such electric drive valves include a direct acting type that directly moves a valve body by an electric drive device to open and close the valve, and a pilot type that opens and closes a pilot valve by an electric drive device and opens and closes a main valve in response to the opening and closing of the pilot valve. These drive valves are properly selected according to the intended use.

[0004] Further, the following Patent Document 1 is a document disclosing a pilot type electromagnetic valve.

Prior Art Document

Patent Document

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] By the way, in recent years, from the viewpoints of improving safety and reducing environmental impact, the use of CO2 refrigerant has been promoted in refrigeration cycle devices.

[0007] However, when using a high-pressure refrigerant such as CO2 refrigerant, since the valve port is closed at high pressure when the valve is closed, it is necessary to use a material with high hardness (for example, metal or hard resin) for the valve body in order to prevent the so-called sagging (deformation and performance deterioration due to long-term use) of the valve body. For this reason, it is difficult to reduce the valve leakage amount.

[0008] On the other hand, if a pressure cancellation structure that introduces the pressure on the lower side (valve seat side) of the valve body to the upper side (opposite side to the valve seat) of the valve body can be adopted, the load applied to the valve body when the valve is closed can be reduced. Therefore, it becomes possible to reduce the valve leakage amount by using a valve body made of a soft material. However, in a conventional pilot-operated valve, due to its structure, it is impossible to have such a pressure cancellation structure.

[0009] Therefore, an object of the present invention is to present a new pilot-type valve structure having a pressure cancellation structure, enabling the use of a valve body made of a soft material, and reducing the valve leakage amount.

Means for Solving the Problem

[0010] In order to solve the above problems and achieve the object, an electric drive valve according to the present invention (sometimes simply referred to as a "drive valve" in this application) is a pilot-type electric drive valve including a main valve that opens and closes a refrigerant flow path, a pilot valve that controls the main valve, and an electric drive device that drives the pilot valve, and has the following structure.

[0011] The main valve includes a valve body having a main valve chamber, an inflow hole for allowing refrigerant to flow into the main valve chamber through a main valve port opening into the main valve chamber, and an outflow hole for allowing refrigerant to flow out from the main valve chamber, a main valve body provided in the main valve chamber so as to be movable forward and backward with respect to a main valve seat formed at an end of the main valve port on the main valve chamber side and opening and closing the main valve port, and a main valve closing spring that biases the main valve body toward the main valve seat.

[0012] The pilot valve has a pilot valve chamber, a pilot flow path that connects the pilot valve chamber and the outflow hole, a pilot valve seat formed at the end of the pilot flow path on the pilot valve chamber side, and a pilot valve body that is driven by the electric drive device and moves forward and backward with respect to the pilot valve seat to open and close the pilot flow path.

[0013] Further, the electric drive valve includes a connection member fixed to the valve body so as to close the top surface of the main valve chamber. Furthermore, along the axial direction (along the axis) of the electric drive valve, the main valve, the pilot valve, and the electric drive device are arranged in this order.

[0014] The pilot valve chamber has a first pilot chamber formed on the upper surface side of the connection member and a second pilot chamber formed on the lower surface side of the connection member. The pilot valve seat is formed in the first pilot chamber. The pilot valve body is arranged in the first pilot chamber. Further, the main valve port opens at the bottom surface portion of the main valve chamber. The outflow hole opens at the side surface portion of the main valve chamber. Furthermore, the electric drive valve has a communication path that connects the first pilot chamber and the second pilot chamber, and an introduction path that connects the inflow hole and the second pilot chamber.

[0015] In the present invention, the axial direction of the electric drive valve is defined as the vertical direction, the direction from the main valve toward the electric drive device is "up", and the direction from the electric drive device toward the main valve is "down". Also, based on the concepts of "up" and "down", terms related to up and down such as "upper side", "lower side", "above", "below", "upper part", and "lower part" are used in this application. However, since the drive valve of the present invention (similarly for the embodiments described later) can be used in various orientations, it is not always the case that "down" is the direction of gravity and "up" is the direction opposite to gravity.

[0016] Further, the present invention typically relates to a solenoid valve, i.e., a solenoid valve that uses an electromagnetic actuator as a driving device for driving a pilot valve as in the embodiments described later, but it is also possible to use an electric motor as the driving device (to make it an electric valve). This is because it is possible to move the pilot valve body up and down by an electric motor as well, and thus the object of the present invention can be achieved. Therefore, in the present application, these solenoid valves and electric valves are collectively referred to as "electrically driven valves" or "driven valves".

[0017] In conventional pilot - type driven valves, generally, refrigerant is made to flow into the main valve chamber from the side surface of the main valve chamber and out from the bottom surface of the main valve chamber (such a flow path arrangement is referred to as "lateral downstream flow" in the present application). In contrast, in the driven valve of the present invention, contrary to the conventional one, refrigerant is made to flow into the main valve chamber through a main valve port that communicates with the inflow hole and opens at the bottom portion of the main valve chamber, and out from an outflow hole that opens at the side portion of the main valve chamber (such a flow path arrangement is referred to as "down - lateral flow" in the present application). In addition to this, an introduction path is provided to communicate the lower side (inflow hole and main valve port) and the upper side (second pilot chamber) of the main valve body. Thereby, it is possible to introduce the high refrigerant pressure in the main valve port (inflow hole) to the upper side of the main valve body, and it becomes possible to reduce or eliminate the pressure difference between the upper and lower surfaces of the main valve body. Therefore, according to the present invention, a soft material with relatively low hardness (and thus high sealing performance) can be used for the main valve body, and the valve leakage amount can be reduced. When using a soft material for the main valve body in this way, it is not necessary for the entire main valve body to be formed of the soft material, and it is sufficient that at least the portion that contacts the main valve seat and closes the main valve port is formed of the soft material.

[0018] Also, in one aspect of the present invention, the diameter of the main valve body is made to match the diameter of the main valve seat. According to such an aspect, the pressure difference between the upper and lower surfaces of the main valve body can be eliminated, and the load applied to the main valve body can be made only the spring load of the main valve closing spring. Therefore, it is possible to configure an electrically driven valve with good valve leakage performance (less valve leakage amount due to having a soft valve body) that can be used regardless of the type of refrigerant (whether the operating pressure of the refrigerant is low or high).

[0019] In the present invention, it is also possible to make the diameter of the main valve body larger than the diameter of the main valve seat. According to such an aspect, the closing valve load (the pressing force of the main valve body against the main valve seat when the valve is closed) can be increased, and the valve leakage amount can be further reduced.

[0020] Furthermore, in the present invention, it is preferable that both the diameter of the main valve body and the diameter of the main valve seat are larger than the diameter of the inflow hole. This is because even if the differential pressure generated on the upper and lower surfaces of the main valve body is small, the load generated on the main valve body due to the differential pressure can be increased, and the main valve body can be more reliably actuated (slid).

[0021] Also, in the present invention, since the flow path arrangement (the flow direction of the refrigerant) is a downward horizontal flow in which the refrigerant flows in from the main valve port, the main valve body that advances toward the main valve port during the closing valve operation is pushed by the refrigerant flowing into the main valve chamber, and the closing speed of the main valve is slower than that of the conventional horizontal downstream flow structure in which the refrigerant flows out from the main valve port. Therefore, according to the present invention, the impact received by the main valve body during the closing valve operation can be alleviated, and it is also possible to improve the durability of the electric drive valve (the main valve body, particularly the main valve body using a soft material).

Effects of the Invention

[0022] According to the present invention, it is possible to use a valve body made of a soft material and reduce the valve leakage amount.

[0023] Other objects, features, and advantages of the present invention will be clarified by the following description of the embodiments of the present invention based on the drawings. It should be noted that the present invention is not limited to the following embodiments, and it is obvious to those skilled in the art that various changes can be made within the scope described in the claims. Also, in each figure, the same reference numerals indicate the same or corresponding parts.

Brief Description of the Drawings

[0024]

Figure 1

Figure 2

Figure 3

[0025] An electric drive valve according to an embodiment of the present invention will be described with reference to FIGS. 1 to 3. The electric drive valve according to the present embodiment is a solenoid valve that opens and closes a refrigerant flow path in a refrigeration cycle device such as a heat pump type air conditioning system, for example. The solenoid valve includes a main valve that opens and closes the refrigerant flow path, a pilot valve that controls the main valve, and an electromagnetic drive device that drives the pilot valve, and is a normally closed type pilot-operated solenoid valve that is in a closed state when not energized.

[0026] Describing the details of each part, as shown in FIGS. 1 to 3, the main valve includes a valve body 12 having a main valve chamber 13, an inflow hole 16 for allowing refrigerant to flow into the main valve chamber 13 through the main valve port 14, and an outflow hole 17 for allowing refrigerant to flow out from the main valve chamber 13, a main valve body 18 that opens and closes the main valve port 14, and a closing spring (referred to as "lower closing spring" / corresponding to the main valve closing spring described in the present invention) 25 that biases the main valve body 18 downward.

[0027] The valve body 12 has an upper surface opening 12a that communicates with the main valve chamber 13. The main valve port 14 opens upward at the center of the bottom surface of the main valve chamber 13. A main valve seat 15 with which the main valve body 18 comes into contact and separates (contacts or separates) is formed on the upper surface portion of the main valve port 14. The inflow hole 16 communicates with the main valve chamber 13 through the main valve port 14. The outflow hole 17 opens on the side surface (circumferential surface) of the main valve chamber 13.

[0028] On the one hand, the pilot valve includes a pilot valve chamber 26 composed of an upper pilot chamber 27 and a lower pilot chamber 28 that communicate with each other through a communication passage 29, a pilot flow passage 30 that connects the pilot valve chamber 26 (upper pilot chamber 27) and the outflow hole 17, a pilot valve seat 31 formed at the end of the pilot flow passage 30 on the upper pilot chamber 27 side, and a pilot valve body 32 that is driven by an electromagnetic drive device 38 to move forward and backward with respect to the pilot valve seat 31 to open and close the pilot flow passage 30.

[0029] On the upper surface portion of the valve body 12, a connecting member 33 is fixed that closes the upper surface of the main valve chamber 13 (the upper surface opening 12a of the valve body 12) and is interposed between the valve body 12 and the electromagnetic drive device 38 to connect them (the valve body 12 and the electromagnetic drive device 38). This connecting member 33 has a flange portion 34 that projects outward from the upper surface opening 12a of the valve body 12 and abuts against the upper surface of the valve body 12, a fitting portion 35 that is fitted into the upper surface opening 12a of the valve body 12, and a cylindrical cylinder portion 36 that projects vertically downward from the lower surface of the fitting portion 35.

[0030] Note that an internal thread 12b is formed on the inner peripheral surface of the upper surface opening 12a of the valve body 12, while an external thread 37 that engages with this internal thread 12b is formed on the outer peripheral surface of the fitting portion 35 of the connecting member 33. Therefore, the connecting member 33 is fixed to the valve body by screwing the fitting portion 35 into the upper surface opening 12a.

[0031] At the center of the upper surface of the connecting member 33, a bottomed and lidless (bottom closed and top open) hole is formed, and the inside of this hole is used as an upper pilot chamber (corresponding to the first pilot chamber referred to in the present invention) 27. At the center of the bottom surface of the upper pilot chamber 27, a pilot flow path 30 is opened, and a pilot valve seat 31 is formed at the upper end thereof. The pilot valve body 32 opens and closes the pilot flow path 30 by contacting and separating from this pilot valve seat 31. The pilot flow path 30 is drilled inside the connecting member 33, and the end on the side opposite to the pilot valve seat 31 (upper pilot chamber 27) communicates with the outflow hole 17 even when the main valve body 18 is seated on the main valve seat 15, and is opened at the peripheral edge of the main valve chamber 13 (outside the main valve body 18) at the peripheral edge of the lower surface of the fitting portion 35.

[0032] The electromagnetic drive device 38 installed on the upper part of the connecting member 33 has a sleeve 39, a plunger 40, an attractor 41, a coil 42, and a closing valve spring 43.

[0033] The sleeve 39 is a bottomless and lidless (both upper and lower ends open) cylindrical member, and is fixed to the connecting member 33 so as to rise vertically upward from the upper surface portion of the connecting member 33 (upper edge portion of the upper pilot chamber 27). The fixing of the sleeve 39 to the connecting member 33 is performed by fitting the lower end portion of the sleeve 39 into the upper pilot chamber 27 and welding it, for example. Inside the sleeve 39, the plunger 40 is slidably accommodated in the vertical direction. At the center of the lower surface of the plunger 40, the pilot valve body 32 is fixed.

[0034] At the upper end of the sleeve 39, the attractor 41 is fixed so as to be able to attract the plunger 40. A coil 42 is installed outside the sleeve 39 (outer peripheral portion). Further, a closing valve spring (referred to as an "upper closing valve spring") 43 is provided between the attractor 41 and the plunger 40. The upper closing valve spring 43 is a compression coil spring, and biases the pilot valve body 32 toward the pilot valve seat 31 (downward) via the plunger 40.

[0035] Further, at the center of the lower surface of the fitting portion 35 of the connection member 33, a hole having a circular cross section that is integral with the internal space of the cylinder portion 36 (in other words, formed at the center of the lower surface of the fitting portion 35 continuously with the internal space so as to extend the internal space of the cylinder portion 36 upward) is formed, and a guide hole that slidably supports the main valve body 18 is constituted by the hole and the internal space of the cylinder portion 36. The upper end portion of the main valve body 18 is slidably fitted into the guide hole in the vertical direction, whereby the main valve body 18 is supported inside the main valve chamber 13.

[0036] The main valve body 18 has a cylindrical overall shape and has a partition wall 19 that horizontally extends at an intermediate position in the vertical direction and partitions the inside of the main valve body 18 vertically. The space above the partition wall 19, together with the upper space of the guide hole, forms a lower pilot chamber (corresponding to the second pilot chamber referred to in the present invention) 28. The lower pilot chamber 28 is provided with the lower closing spring 25. The lower closing spring 25 is installed in a compressed state between the upper surface of the partition wall 19 and the ceiling surface of the guide hole (the lower surface of the fitting portion 35 of the connection member 33).

[0037] Further, at the center of the connection member 33 (more precisely, at a position slightly offset outward from the center in order to form the pilot valve seat 31 at the center of the connection member 33), the communication passage 29 that communicates the lower pilot chamber 28 and the upper pilot chamber 27 is formed so as to penetrate the connection member 33 in the vertical direction.

[0038] Furthermore, on the outer peripheral surface of the upper end portion of the main valve body 18, a sealing material is provided that is interposed between the main valve body 18 and the inner peripheral surface of the guide hole. This sealing material consists of an O-ring 21 and a lip seal 22 disposed outside the O-ring 21, and functions to block the communication between the main valve chamber 13 and the lower pilot chamber 28.

[0039] On the outer peripheral surface of the lower end portion of the main valve body 18, a ring-shaped packing 23 made of a soft material (such as rubber or PTFE (polytetrafluoroethylene)) that is advantageous for reducing the valve leakage amount is provided. When the valve is closed, the packing 23 abuts against the main valve seat 15, thereby closing the main valve port 14. A washer 24 for preventing the packing 23 from falling off is provided on the lower surface of the packing 23.

[0040] Also, an introduction passage 20 that penetrates the partition wall 19 in the vertical direction is formed in the partition wall 19. This introduction passage 20 introduces the high refrigerant pressure in the main valve port 14 (inflow hole 16) to the upper surface side (lower pilot chamber 28) of the main valve body 18, and has a smaller flow path diameter than the pilot flow path 30.

[0041] Furthermore, both the main valve body 18 and the main valve port 14 (main valve seat 15) have a circular cross-sectional shape. In this embodiment, their diameters D1 (the diameter D1 of the main valve body 18 and the diameters D1 of the main valve port 14 and the main valve seat 15) are made equal. This is to eliminate the pressure difference between the upper and lower surfaces (upper side and lower side) of the main valve body 18 and make the load applied to the main valve body 18 only the spring load of the lower closing spring 25. Thus, in combination with using a packing 23 made of a soft material for the main valve body 18, an electromagnetic valve 11 with good valve leakage performance that can be used regardless of the type of refrigerant (operating pressure) can be configured. Also, since the load on the main valve body 18 (packing 23) pressed against the main valve seat 15 in the closed valve state can be reduced, it is also possible to improve the durability of the electromagnetic valve 11.

[0042] Also, in this embodiment, the diameter D1 of the main valve body 18 is made larger than the diameter (flow path diameter) D2 of the inflow hole 16 having a circular cross-sectional shape. This is to increase the load generated on the main valve body 18 by the differential pressure even if the differential pressure generated on the upper and lower surfaces of the main valve body 18 is small, and to more reliably operate (slide) the main valve body 18.

[0043] The operation of the electromagnetic valve 11 according to this embodiment is described as follows.

[0044] When the coil 42 is not energized, as shown in Fig. 1, the plunger 40 is pushed down by the upper closing valve spring 43, the pilot valve body 32 seats on the pilot valve seat 31, and the pilot flow path 30 is closed. Therefore, the internal pressure of the pilot valve chamber 26 (the upper pilot chamber 27 and the lower pilot chamber 28) communicating with the inlet hole 16 via the main valve port 14, the introduction path 20, and the communication path 29 is equal to the internal pressure of the inlet hole 16, and the main valve body 18 is pressed against the main valve seat 15 by the biasing force of the lower closing valve spring 25 to maintain the closed valve state.

[0045] Here, when the coil 42 is energized, as shown in Fig. 2, the plunger 40 is attracted by the attractor 41 and rises against the biasing force of the upper closing valve spring 43, the pilot valve body 32 separates from the pilot valve seat 31, and the pilot flow path 30 is opened. As a result, the refrigerant in the pilot valve chamber 26 is discharged to the outlet hole 17 through the pilot flow path 30, and the internal pressure of the pilot valve chamber 26 decreases. Also, the flow path cross-sectional area of the pilot flow path 30 is larger than that of the introduction path 20, and the amount of refrigerant discharged from the pilot valve chamber 26 to the outlet hole 17 through the pilot flow path 30 is larger than the amount of refrigerant flowing into the pilot valve chamber 26 from the inlet hole 16 through the introduction path 20. Therefore, the internal pressure of the pilot valve chamber 26 is lower than the internal pressure of the inlet hole 16 (main valve port 14), and a differential pressure that pulls the main valve body 18 upward is generated on the upper and lower surfaces of the main valve body 18.

[0046] Then, as shown in Fig. 3, the main valve body 18 is pushed up against the biasing force of the lower closing valve spring 25, and the main valve port 14 is opened to an open valve state. In this open valve state, the refrigerant (see reference numeral F1) flowing into the main valve chamber 13 from the inlet hole 16 through the main valve port 14 is discharged through the outlet hole 17 (see reference numeral F2). Note that the pushed-up main valve body 18 abuts against the lower surface of the fitting portion 35 of the connecting member 33 (the stepped portion formed at the peripheral edge of the ceiling surface of the guide hole) and stops.

[0047] On the other hand, when the power supply to the coil 42 is stopped in this valve open state, the suction force of the attractor 41 disappears and the plunger 40 is released from the attractor 41, so that the plunger 40 is pushed downward by the upper valve-closing spring 43, the pilot valve element 32 seats on the pilot valve seat 31, and the pilot flow path 30 is closed. Then, refrigerant flowing into the pilot valve chamber 26 through the introduction path 20 accumulates in the pilot valve chamber 26, and the internal pressure of the pilot valve chamber 26 increases. As a result, the pressure difference between the upper and lower surfaces of the main valve element 18 disappears, and the main valve element 18 is pushed down by the biasing force of the lower valve-closing spring 25, resulting in a valve-closed state in which the main valve element 18 seats on the main valve seat 15 (see FIG. 1). [Explanation of symbols]

[0048] A Center axis D1 Diameter of the main valve body and main valve port (main valve seat) D2 Diameter of inflow hole (flow path diameter) F1, F2 refrigerant flow 11 Electrically driven valve (solenoid valve) 12 Valve body 12a Top opening 12b female thread 13 Main valve chamber 14 Main valve port 15 Main valve seat 16 Inflow hole 17 Outflow hole 18 Main valve body 19 Bulkhead 20 Introductory path 21 O-ring 22 Lip seal 23 Gasket 24 washer 25 Lower valve closing spring 26 Pilot valve chest 27 Upper Pilot Room 28 Lower pilot compartment 29 Communication path 30 Pilot channel 31 Pilot valve seat 32 Pilot valve body 33 Connecting member 34 Flange 35 Embedded part 36 Cylinder part 37 Male thread 38 Electromagnetic drive device 39 Sleeve 40 Plunger 41 Attractor 42 Coil 43 Upper valve closing spring

Claims

1. A main valve for opening and closing a refrigerant flow path, a pilot valve for controlling the main valve, and an electric drive device for driving the pilot valve, wherein the main valve comprises a valve body having a main valve chamber, an inlet hole for allowing refrigerant to flow into the main valve chamber through a main valve port opening into the main valve chamber, and an outlet hole for allowing the refrigerant to flow out of the main valve chamber, a main valve body provided in the main valve chamber so as to be movable forward and backward with respect to a main valve seat formed at an end of the main valve port on the main valve chamber side, for opening and closing the main valve port, and a main valve closing spring for urging the main valve body toward the main valve seat, and has wherein the pilot valve comprises a pilot valve chamber, a pilot flow path for communicating the pilot valve chamber with the outlet hole, a pilot valve seat formed at an end of the pilot flow path on the pilot valve chamber side, and a pilot valve body driven by the electric drive device, for moving forward and backward with respect to the pilot valve seat to open and close the pilot flow path, and has further comprising a connecting member fixed to the valve body so as to close the top surface of the main valve chamber is an electric drive valve, wherein the main valve, the pilot valve, and the electric drive device are arranged in this order in the axial direction of the electric drive valve. When the axial direction is defined as the vertical direction, the direction from the main valve toward the electric drive device is "up", and the direction from the electric drive device toward the main valve is "down", wherein the pilot valve chamber comprises a first pilot chamber formed on the upper surface side of the connecting member, and a second pilot chamber formed on the lower surface side of the connecting member, and has wherein the pilot valve seat is formed in the first pilot chamber, the pilot valve body is arranged in the first pilot chamber, the main valve port opens at the bottom surface portion of the main valve chamber, the outlet hole opens at the side surface portion of the main valve chamber, wherein the electric drive valve comprises a communication path for communicating the first pilot chamber and the second pilot chamber, and an introduction path for communicating the inlet hole and the second pilot chamber, and has an electric drive valve characterized by the above.

2. The electric drive valve according to claim 1, wherein the diameter of the main valve body is made to match the diameter of the main valve seat.

3. The electric drive valve according to claim 1 or 2, wherein both the diameter of the main valve body and the diameter of the main valve seat are made larger than the diameter of the inlet hole. ​ ​

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