CN106545670B - Direct-acting solenoid valve and four-way selector valve provided with same as pilot valve - Google Patents

Abstract

The invention provides a direct-acting solenoid valve and a four-way switching valve having the same, which can effectively reduce noise and can rapidly switch without greatly reducing the frequency of a compressor when switching from heating operation to defrosting operation and from defrosting operation to heating operation. According to a voltage applied to a solenoid coil (51) of a direct-acting solenoid valve (50), a first plunger (61) and a second plunger (62) are respectively in an attraction position and a non-attraction position, a first valve body (71) is in one end position for communicating a port (p1) and a port (p2) and in the other end position for communicating the port (p2) and the port (p3) in linkage with the attraction position and the non-attraction position, a second valve body is in an opening position for opening the port (p4) and in a closing position for closing the port (p4), and when switching from a defrosting operation to a heating operation and from the heating operation to the defrosting operation, the second valve body (72) is in the opening position, and the pressure of a main valve chamber (12) is reduced to a predetermined pressure.

Description

Direct-acting solenoid valve and four-way selector valve provided with same as pilot valve

Technical Field

The present invention relates to a guide-type four-way switching valve for switching flow paths in a heat pump type cooling and heating system or the like, and more particularly, to a direct-acting solenoid valve capable of effectively reducing noise generated when switching operations before and after a defrosting operation, and a four-way switching valve provided as a guide valve.

Background

Generally, a heat pump type cooling and heating system such as an indoor air conditioner or a car air conditioner includes a four-way switching valve as a flow path (flow direction) switching means in addition to a compressor, an outdoor heat exchanger, an indoor heat exchanger, an expansion valve, and the like.

An example of a heat pump type cooling and heating system including such a four-way switching valve will be briefly described with reference to fig. 23A and 23B. The heat pump type cooling and heating system 200 illustrated in the drawing is configured to perform switching between a cooling operation (and a defrosting operation) and a heating operation by a four-way switching valve 240 serving as a flow path switching valve, and basically includes a compressor 210, an outdoor heat exchanger 220, an indoor heat exchanger 230, and an expansion valve 260, and the four-way switching valve 240 having 4 ports, that is, a discharge-side high-pressure port D, an outdoor-side output port C, an indoor-side output port E, and an intake-side low-pressure port S, is disposed between a discharge side and an intake side of the compressor 210, the outdoor heat exchanger 220, and the indoor heat exchanger 230.

The respective devices are connected to each other by a flow path formed by a pipe (duct) or the like, and during the cooling operation, as shown in fig. 23A, the discharge-side high-pressure port D of the four-way switching valve 240 communicates with the outdoor-side inlet port C, and the indoor-side inlet port E communicates with the suction-side low-pressure port S. Thus, the refrigerant is sucked into the compressor 210, and the high-temperature and high-pressure refrigerant from the compressor 210 is introduced into the outdoor heat exchanger 220 through the four-way switching valve 240, condensed by exchanging heat with outdoor air, changed into a high-pressure two-phase refrigerant, and introduced into the expansion valve 260. The high-pressure refrigerant is decompressed by the expansion valve 260, the decompressed low-pressure refrigerant is introduced into the indoor heat exchanger 230, where it exchanges heat (cools) with the indoor air and is evaporated, and the low-temperature low-pressure refrigerant from the indoor heat exchanger 230 is returned to the suction side of the compressor 210 by the four-way switching valve 240.

In contrast, during the heating operation, as shown in fig. 23B, the discharge-side high-pressure port D of the four-way switching valve 240 communicates with the indoor-side outlet port E, and the outdoor-side outlet port C communicates with the suction-side low-pressure port S, so that the high-temperature and high-pressure refrigerant is introduced from the compressor 210 into the indoor heat exchanger 230, is subjected to heat exchange (heating) with the indoor air, is condensed, is converted into a high-pressure two-phase refrigerant, and is introduced into the expansion valve 260. The high-pressure refrigerant is decompressed by the expansion valve 260, the decompressed low-pressure refrigerant is introduced into the outdoor heat exchanger 220, exchanges heat with outdoor air and evaporates therein, and the low-temperature low-pressure refrigerant from the outdoor heat exchanger 220 is returned to the suction side of the compressor 210 by the four-way switching valve 240.

In this heating operation, conventionally, in order to remove (melt) frost adhering to the outdoor heat exchanger 220 as needed (usually periodically), a cycle reverse to the heating operation, that is, a cycle similar to the cooling operation is performed in a short time to circulate the refrigerant, thereby heating the outdoor heat exchanger 220 to perform the defrosting operation, and the defrosting operation is resumed after the defrosting operation is terminated.

However, when switching from the heating operation to the defrosting operation (when switching the flow path), the port into which the high-pressure refrigerant flows is switched from the indoor side outlet port E to the outdoor side outlet port C, and when switching from the defrosting operation to the heating operation, the port into which the high-pressure refrigerant flows is switched from the outdoor side outlet port C, which is opposite to the indoor side outlet port E. Then, during this switching, the opening areas of the two ports change rapidly, and the high-pressure refrigerant flows into the low-pressure-side port (conduit) at once, causing a rapid pressure change in the system 200, which causes a problem of generation of loud noise (switching sound).

In order to reduce this noise, conventionally, as disclosed in, for example, patent documents 1 and 2, the operation is switched after the operation (flow path) is switched after the compressor is stopped or the frequency (number of revolutions) of the compressor is gradually reduced to reduce the pressure difference between the high pressure side and the low pressure side (to the extent that the noise can be tolerated).

Patent document 1: japanese laid-open patent publication No. 6-247135

Patent document 2: japanese patent laid-open publication No. 2003-240391

Disclosure of Invention

However, when the compressor is stopped or the frequency (number of revolutions) of the compressor is decreased to gradually decrease the pressure difference between the high pressure side and the low pressure side when switching from the heating operation to the defrosting operation as described above, although noise can be reduced, there are the following problems: the time required from the heating operation to actually performing the defrosting operation is substantially long, and as in the case of switching from the defrosting operation to the heating operation, it takes a long time for the pressure of the refrigerant to return to the required high pressure, and it takes a long time for the warm air to come out of the indoor heat exchanger.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a direct-acting solenoid valve and a four-way selector valve provided as a pilot valve, which can effectively reduce noise without significantly reducing the compressor frequency and can quickly switch from the heating operation to the defrosting operation and from the defrosting operation to the heating operation, when switching from the heating operation to the defrosting operation and from the defrosting operation to the heating operation.

To achieve the above object, a direct-acting solenoid valve according to the present invention is basically formed as follows: a valve housing having an electromagnetic coil fixed to an outer periphery of one end side thereof, a suction member, a first plunger, and a second plunger arranged in series in this order from one end side, an extension portion extending to the suction member side through an outer side of the first plunger is provided in a part of the second plunger, an area of the extension portion on a side close to the suction member is formed smaller than an area of the first plunger on a side close to the suction member, a main port is provided on the valve housing on a side closer to the second plunger than the other end side, a valve seat having first, second, third, and fourth ports is provided, a first valve element linked to the first plunger is slidably abutted to switch a communication state between the first, second, and third ports, and a second valve element linked to the second plunger is slidably abutted to switch the fourth port or disposed to be distant from and close to the second port And two spools, the first plunger and the first spool and the second plunger and the second spool being respectively in a plurality of positions according to a voltage applied to the electromagnetic coil.

In a further preferred embodiment, the direct-acting solenoid valve is formed in the following manner: a valve housing having an electromagnetic coil fixed to an outer periphery of one end side, a suction member, a first spring formed by a compression coil spring, a first plunger, a second spring formed by a compression coil spring, and a second plunger arranged in series in this order from the one end side, wherein an extension portion extending to the suction member side through an outer side of the first plunger is provided in a part of the second plunger, an area of the extension portion on a side close to the suction member is formed smaller than an area of the first plunger on a side close to the suction member, a first stopper and a second stopper are provided to prevent the first plunger and the second plunger from moving to the other end side, a high-pressure introduction port is provided on the other end side of the valve housing than the second plunger, and a valve seat having first, second, third, and fourth ports is provided on the valve seat, a sliding first valve body that is pushed and pulled by the first plunger is slidably abutted so as to switch a communication state between the first, second, and third ports, a sliding second valve body pushed and pulled by the second plunger or a poppet second valve body disposed so as to be movable away from and close to each other is slidably engaged with the fourth port, the first plunger and the second plunger are respectively in an attracting position and a non-attracting position according to a voltage applied to the electromagnetic coil, the first spool is interlocked with the first plunger at one end position at which the first port and the second port are communicated and at the other end position at which the second port and the third port are communicated, the second spool is interlocked with the second plunger to be in an open position for opening the fourth port and a closed position for closing the fourth port.

In a preferred embodiment, the direct-acting solenoid valve is formed in the following manner: in a state where the electromagnetic coil is stopped from being energized, the first plunger is in a non-attracting position where the first stopper is in abutment with the first plunger and the second plunger is in a non-attracting position where the second stopper is in abutment with the second plunger, whereby the first valve body is in the other end position and the second valve body is in the closed position, and in this state, when a first voltage is applied to the electromagnetic coil, the first plunger is still in the non-attracting position where the first stopper is in abutment with the first plunger, the second plunger is in an attracting position where the second plunger is drawn toward the first plunger side and the extending portion is in abutment with the attracting member against the urging force of the second spring, whereby the first valve body is still in the other end position and the second valve body is still in the open position, in this state, when a second voltage higher than the first voltage is applied to the electromagnetic coil, the first plunger is in an attraction position pulled up by the attraction member against the urging force of the first spring, but the second plunger is still in the attraction position, so that the first spool is in the one end position and the second spool is still in the open position, and in this state, when a third voltage lower than the first and second voltages is applied to the electromagnetic coil, the first plunger is still held in the attraction position by the attraction member, the second plunger is returned to the non-attraction position by the urging force of the second spring, so that the first spool is still in the one end position and the second spool is returned to the closed position.

In other preferred embodiments, the direct-acting solenoid valve is formed in the following manner: in a state where the third voltage is applied to the electromagnetic coil, the first plunger is held at the attraction position by the attraction force of the attraction member, and the second plunger is also held at the non-attraction position, when the second voltage is applied to the electromagnetic coil, the first plunger is held at the attraction position, the second plunger is held at the attraction position, which is drawn toward the first plunger side against the urging force of the second spring and in which the extension portion abuts against the attraction member, whereby the first valve body is held at the one end position and the second valve body is held at the open position, and thereafter, when the electromagnetic coil is stopped to be energized, the first plunger is returned to the non-attraction position by the urging force of the first spring, and the second plunger is returned to the non-attraction position by the urging force of the second spring, thereby, the first spool is returned to the other end position, and the second spool is returned to the closed position.

In another preferred embodiment, a permanent magnet is disposed on one end side of the suction member of the valve housing.

In a further preferred embodiment, the direct-acting solenoid valve is formed in the following manner: in a state where the electromagnetic coil is stopped from being energized, the first plunger is in a non-attracting position where the first stopper is in abutment with the first plunger and the second plunger is in a non-attracting position where the second stopper is in abutment with the second plunger, whereby the first valve body is in the other end position and the second valve body is in the closed position, and in this state, when a first voltage is applied to the electromagnetic coil, the first plunger is still in the non-attracting position where the first stopper is in abutment with the first plunger, the second plunger is in an attracting position where the second plunger is drawn toward the first plunger side and the extending portion is in abutment with the attracting member against the urging force of the second spring, whereby the first valve body is still in the other end position and the second valve body is still in the open position, in this state, when a second voltage higher than the first voltage is applied to the electromagnetic coil, the first plunger is in an attraction position drawn by the attraction member against the urging force of the first spring, but the second plunger is still in the attraction position, so that the first valve element is in the one end position, and the second valve element is still in the open position.

In other preferred embodiments, the direct-acting solenoid valve is formed in the following manner: in a state where the current supply to the electromagnetic coil is stopped, the first plunger is held at the attraction position by the magnetic force of the permanent magnet, and the second plunger is also held at the non-attraction position, when the second voltage is applied to the electromagnetic coil, the first plunger is held at the attraction position, the second plunger is at the attraction position where the second plunger is drawn toward the first plunger side against the urging force of the second spring and the extension portion abuts against the attraction member, whereby the first spool is still at the one end position, the second spool is at the open position, and thereafter, when a third voltage of opposite polarity is applied to the electromagnetic coil, the magnetic force of the permanent magnet is cancelled, the first plunger is returned to the non-attraction position by the urging force of the first spring, and the second plunger is returned to the non-attraction position by the urging force of the second spring, as a result, the first spool is returned to the other end position and the second spool is returned to the closed position, and then, when the electromagnetic coil is stopped from being energized, the first plunger maintains the non-attracting position, the second plunger maintains the non-attracting position, the first spool maintains the other end position, and the second spool maintains the closed position.

In another aspect, the present invention provides a four-way switching valve of a sliding type for switching a refrigerant flow direction used in a heat pump type air-cooling/heating system configured to be capable of selecting an air-cooling operation, an air-heating operation, and a defrosting operation in which a refrigerant flows in the same direction as during the air-cooling operation, the four-way switching valve including: the direct-acting solenoid valve having the above-described configuration is provided as a pilot valve, and includes a cylinder-type four-way valve body in which a first working chamber, a first piston, a main valve chamber, a second piston, and a second working chamber are arranged in this order from one end side, a discharge-side high-pressure port connected to a discharge side of a compressor is provided in the main valve chamber, a main valve seat is provided, an outdoor-side inlet port connected to an outdoor heat exchanger, a suction-side low-pressure port connected to a suction side of the compressor, and an indoor-side inlet port connected to an indoor heat exchanger are provided in this order from one end side in a valve seat surface of the main valve seat, and a main valve body having an inverted bowl-shaped cross section is slidably abutted to the main valve body, and the main valve body can be selectively placed in a cooling position where the outdoor-side inlet port is opened and the suction-side low-pressure port and the indoor-side inlet port, And a heating position where the indoor side inlet/outlet port is opened and the suction side low-pressure port and the outdoor side inlet/outlet port are communicated, wherein the high-pressure inlet port of the direct-acting solenoid valve is connected to the discharge side high-pressure port, the first port is connected to the first working chamber, the second port is connected to the suction side low-pressure port, the third port is connected to the second working chamber, and the fourth port is connected to the suction side low-pressure port, so that the second valve body of the direct-acting solenoid valve is in an open position where the fourth port is opened when switching from defrosting operation to heating operation and from heating operation to defrosting operation, and the pressure in the main valve chamber can be reduced to a predetermined pressure.

Another four-way switching valve according to the present invention is a rotary four-way switching valve for switching a refrigerant flow direction used in a heat pump type air-cooling/heating system configured to be capable of selecting a cooling operation, a heating operation, and a defrosting operation in which a refrigerant flows in the same direction as during the cooling operation, the four-way switching valve being configured to: the direct-acting solenoid valve having the above-described configuration is provided as a pilot valve, and includes a main valve having: a cylindrical main valve box for dividing the main valve chamber; a main valve element rotatably disposed in the main valve chamber; and an actuator having a first working chamber and a second working chamber, which are variable in volume and selectively introduce or discharge a high-pressure refrigerant, for rotating the main valve element, wherein the main valve box is provided with a discharge-side high-pressure port connected to a discharge side of a compressor, an outdoor-side inlet port connected to an outdoor heat exchanger, an intake-side low-pressure port connected to an intake side of the compressor, and an indoor-side inlet port connected to an indoor heat exchanger, and wherein the main valve element is rotated by controlling introduction or discharge of the high-pressure refrigerant into or from the first working chamber and the second working chamber to switch between communication ports, thereby switching from a cooling or defrosting operation to a heating operation and from the heating operation to the cooling or defrosting operation, and the high-pressure inlet port of the direct-acting solenoid valve is connected to the discharge-side high-pressure port, the first port is connected to the first working chamber, the second port is connected to the suction-side low-pressure port, the third port is connected to the second working chamber, and the fourth port is connected to the suction-side low-pressure port, so that the second spool of the direct-acting solenoid valve is placed in an open position in which the fourth port is opened when switching from defrosting operation to heating operation and when switching from heating operation to defrosting operation, and the pressure in the main valve chamber can be reduced to a predetermined pressure.

The four-way selector valve provided with the direct-acting solenoid valve according to the present invention as a pilot valve is configured as follows: when switching from the defrosting operation to the heating operation and when switching from the heating operation to the defrosting operation, the second valve body of the direct-acting solenoid valve is set to the open position, and the pressure of the main valve chamber is gradually reduced to a predetermined pressure.

As described above, according to the present invention, in a heat pump type cooling and heating system, switching from the heating operation to the defrosting operation and from the defrosting operation to the heating operation can be performed quickly while reducing noise, and further, since the solenoid valve other than the direct-acting solenoid valve according to the present invention is not required, the cooling operation, the heating operation, and the defrosting operation can be performed with a relatively simple configuration, and therefore, the installation cost and the component cost can be reduced.

In the direct-acting solenoid valve according to the present invention, since the extension portion that passes through the outside of the first plunger and extends toward the suction member (one end side) is provided in a part of the second plunger, the magnetic effect is increased, and thus, the switching operation of the direct-acting solenoid valve is facilitated when switching from the heating operation to the defrosting operation and from the defrosting operation to the heating operation.

Furthermore, in the case where the direct-acting solenoid valve is not provided with a permanent magnet, the number of components is reduced, and the structure is simpler, and in the case where the direct-acting solenoid valve is formed as a self-holding type solenoid valve provided with a permanent magnet, the energization of the electromagnetic coil can be stopped during the cooling operation (defrosting operation) and the heating operation, and energy can be saved.

Problems, structures, and operational effects other than those described above will be apparent from the following embodiments.

Drawings

Fig. 1 is an overall configuration diagram showing a cooling operation (defrosting operation) of a heat pump type cooling and heating system incorporating a sliding type four-way switching valve including a first embodiment of a direct-acting solenoid valve of the present invention as a pilot valve.

Fig. 2 is a cross-sectional view with a partial plan view showing a cooling operation (defrosting operation) of the four-way valve main body of the four-way switching valve shown in fig. 1.

Fig. 3 is an overall configuration diagram showing a heating operation of the heat pump type air-cooling and heating system incorporating the sliding type four-way switching valve shown in fig. 1.

Fig. 4 is an enlarged sectional view showing a partial plan view of the direct-acting solenoid valve of the first embodiment in cooling operation (defrosting operation) as a pilot valve of the four-way switching valve shown in fig. 1.

Fig. 5A is an enlarged perspective view showing an internal structure of the direct-acting solenoid valve according to the first embodiment.

Fig. 5B is a cross-sectional view taken along the line U-U in fig. 4.

Fig. 5C is a cross-sectional view taken along line V-V in fig. 4.

Fig. 6 is an enlarged cross-sectional view showing the direct-acting solenoid valve of the first embodiment during switching from the defrosting operation to the heating operation (in a state where the voltage V1 is applied).

Fig. 7 is an enlarged cross-sectional view showing the direct-acting solenoid valve of the first embodiment during switching from the defrosting operation to the heating operation (in a state where the voltage V2 is applied).

Fig. 8 is an enlarged cross-sectional view showing the heating operation of the direct-acting solenoid valve (state where the voltage V3 is applied) according to the first embodiment.

Fig. 9 is an enlarged cross-sectional view showing the state in which the direct-acting solenoid valve of the first embodiment is switched from the heating operation to the defrosting operation (the state in which the voltage V2 is applied).

Fig. 10 is a list showing the operation and position of each part of the direct-acting solenoid valve according to the first embodiment in each state.

Fig. 11 is a timing chart showing an outline of the operation, position, and state of each unit of the heat pump type air cooling and heating system according to the first embodiment.

Fig. 12A is a side view showing a rotary four-way switching valve including a pilot valve according to a second embodiment of the direct-acting solenoid valve of the present invention.

Fig. 12B is a top side layout view of a cooling position and a heating position of a rotary four-way switching valve including a pilot valve as a direct-acting solenoid valve according to a second embodiment of the present invention.

Fig. 13 is an overall configuration diagram showing a cooling operation (defrosting operation) of the heat pump type air-cooling system incorporating the rotary four-way switching valve shown in fig. 12A and 12B (shown in the cross section X-X of the cooling position in fig. 12B).

Fig. 14 is an overall configuration diagram showing a heating operation of the heat pump type air-cooling and heating system incorporating the rotary four-way switching valve shown in fig. 12A and 12B (shown in the X-X cross section of the heating position in fig. 12B).

Fig. 15A is a partially enlarged sectional view of a main portion of the actuator shown in fig. 12A.

Fig. 15B is an exploded perspective view of a main part of the motion conversion mechanism shown in fig. 15A.

Fig. 16 is an enlarged sectional view showing a partial plan view of the direct-acting solenoid valve of the second embodiment in cooling operation (defrosting operation) as a pilot valve of the four-way switching valve shown in fig. 13.

Fig. 17 is an enlarged cross-sectional view showing the direct-acting solenoid valve according to the second embodiment during switching from the defrosting operation to the heating operation (in a state where the voltage V1 is applied).

Fig. 18 is an enlarged cross-sectional view showing the direct-acting solenoid valve according to the second embodiment during switching from the defrosting operation to the heating operation (in a state where the voltage V2 is applied).

Fig. 19 is an enlarged cross-sectional view showing a heating operation (non-energization locked state) of the direct-acting solenoid valve according to the second embodiment.

Fig. 20 is an enlarged cross-sectional view showing the direct-acting solenoid valve according to the second embodiment during switching from the heating operation to the defrosting operation (in a state where the voltage V2 is applied).

Fig. 21 is a list showing the operation and position of each part of the direct-acting solenoid valve according to the second embodiment in each state.

Fig. 22 is a timing chart showing an outline of the operation, position, and state of each unit of the heat pump type air cooling and heating system according to the second embodiment.

Fig. 23A is a schematic configuration diagram showing the flow of the refrigerant during the cooling operation (and during the defrosting operation) in an example of the heat pump type cooling and heating system.

Fig. 23B is a schematic configuration diagram illustrating the flow of the refrigerant during the heating operation in an example of the heat pump type air-cooling and heating system.

Description of the reference symbols

1: a four-way switching valve (first embodiment); 2: a four-way switching valve (second embodiment); 10: a four-way valve main body; 11: a cylinder section; 12: a main valve chamber; 14: a main valve seat; 15: a main valve element; 21: a first piston; 22: a second piston; 31: a first working chamber; 32: a second working chamber; 50: a direct-acting solenoid valve (first embodiment); 51: an electromagnetic coil; 53: a permanent magnet; 55: a suction member; 56: a first spring; 57: a second spring; 60: a valve chamber; 61: a first plunger; 62: a second plunger; 64: a contact preventing member; 65: a limiting component; 70: a valve seat; 71: a first valve spool; 72: a second valve core; 75: a first spool holder; 76: a second spool holder; p 1: a first port; p 2: a second port; p 3: a third port; p 4: a fourth port; p10: a high-pressure introduction port (main port); # 1: a first thin tube; # 2: a second thin tube; # 3: a third tubule; # 4: a fourth tubule; # 10: a high-pressure tubule; 80: a direct-acting solenoid valve (second embodiment); 105: a main valve; 107: an actuator; 110: a main valve box; 110A: an upper valve seat; 110B: a lower valve seat; 111: a first working chamber; 112: a second working chamber; 113: a lower port; 114: an upper port; 115: a main valve chamber; 120: a main valve element; 121: a first layer of components; 122: a second layer member; 123: a third layer member; 124: a fourth layer member; 130A: an upper rotary shaft part; 130B: a lower rotary shaft part; 131: a first connecting passage; 132: a second communication path; 133: a third communicating path; 134: a fourth communication path; 152: a lower surface closing member; 153: an upper surface blocking member; 154: a keyway; 155: a working chamber; 158: a motion conversion mechanism; 160: a pressurized moving body; 162: a gasket; 163: a working pin; 165: a rotation driving body; 172: a ball bearing; 175: a helical groove; 176: a rotation driving shaft portion; 177: a rotation transmission mechanism; d: a discharge side high pressure port; s: a suction side low pressure port; c: an outdoor side input port; e: an indoor side inlet port; 200: a heat pump type cooling and heating system; 210: a compressor; 220: an outdoor heat exchanger; 230: an indoor heat exchanger; 260: an expansion valve.

Detailed Description

Hereinafter, specific embodiments of the present invention will be described with reference to the drawings.

[ first embodiment ]

Fig. 1 is an overall configuration diagram showing a cooling operation (defrosting operation) of a heat pump type cooling and heating system incorporating a sliding type four-way switching valve including a first embodiment of a direct-acting solenoid valve of the present invention as a pilot valve, fig. 2 is a sectional view with a partial plan view showing a cooling operation (defrosting operation) of a four-way valve main body of the four-way switching valve shown in fig. 1, fig. 3 is an overall configuration diagram showing a heating operation of the heat pump type cooling and heating system incorporating the sliding type four-way switching valve shown in fig. 1, and fig. 4 is an enlarged sectional view with a partial plan view showing a cooling operation (defrosting operation) of the direct-acting solenoid valve of the first embodiment as a pilot valve of the four-way switching valve shown in fig. 1.

In the present specification, the expressions of the positions and directions such as up and down, left and right, front and back, and the like are attached to the drawings for convenience in order to avoid the complexity of the description, and do not limit the positions and directions to be actually incorporated in the heat pump type cooling and heating system.

In addition, in the drawings, for the sake of easy understanding of the invention, for convenience of drawing, a gap formed between members, a spacing distance between members, and the like may be drawn to be larger or smaller than the size of each constituent member.

The heat pump type cooling and heating system 200 shown in fig. 1 includes: a compressor 210; an outdoor heat exchanger 220; an indoor heat exchanger 230; an expansion valve 260; and a four-way selector valve 1 of the pilot type according to the first embodiment of the present invention.

The four-way selector valve 1 according to the first embodiment is a sliding selector valve, and basically includes: a cylinder-type four-way valve body 10 and a single direct-acting solenoid valve 50 as a pilot valve.

[ Structure of four-way valve body 10 ]

The four-way valve body 10 has a cylinder portion 11, and a first operating chamber 31, a first piston 21, a main valve chamber 12, a second piston 22, and a second operating chamber 32 are arranged in this order from the left end side in the cylinder portion 11. To airtightly separate the cylinder portion 11, a spring-equipped gasket is attached to either one of the first and second pistons 21 and 22, and the outer peripheral portion of the spring-equipped gasket is pressed against the inner peripheral surface of the cylinder portion 11.

A left end cap member 11A is airtightly fixed to the left end of the cylinder portion 11, the left end cap member 11A also serves as a stopper for preventing the first piston 21 from moving in the left direction, and a right end cap member 11B is airtightly fixed to the right end of the cylinder portion 11, the right end cap member 11B also serves as a stopper for preventing the second piston 22 from moving in the right direction.

A discharge-side high-pressure port D formed of a pipe joint connected to the discharge side of the compressor 210 via a conduit is provided at the upper portion of the main valve chamber 12, and the main valve seat 14 having a seat surface formed on the upper surface thereof is joined and fixed to the cylinder portion 11 in an airtight manner by brazing or the like.

An outdoor side inlet/outlet port C formed of a pipe joint connected to the outdoor heat exchanger 220, an intake side low pressure port S formed of a pipe joint connected to the intake side of the compressor 210, and an indoor side inlet/outlet port E formed of a pipe joint connected to the indoor heat exchanger 230 are provided in this order from the left end side on the valve seat surface of the main valve seat 14.

A main valve element 15 having an inverted bowl-shaped cross section is slidably abutted on a seat surface of the main valve chamber 14, and the main valve element 15 has a race-track-shaped annular seal surface.

The main spool 15 is formed as follows: the air conditioner is selectively placed in a cooling position (right end position) where the outdoor side inlet port C is opened and the suction side low pressure port S and the indoor side inlet port E are communicated, as shown in fig. 1 and 2, and in a heating position (left end position) where the indoor side inlet port E is opened and the suction side low pressure port S and the outdoor side inlet port C are communicated, as shown in fig. 3.

When main spool 15 is positioned directly above any two (C and S, S and E) of ports C, S, E except during movement, main spool 15 is pressed downward by the high-pressure refrigerant introduced into main valve chamber 12 and pressed against the seat surface.

The first piston 21 and the second piston 22 are connected to each other so as to be movable integrally by a main connecting body 25 having a horizontally long rectangular plate shape as shown in a plan view of fig. 2. A main connecting body 25 is formed with a round rectangular main opening 25a, and the main valve body 15 is slidably fitted in the main opening 25a from below, and the main valve body 15 is formed as follows: the first and second pistons 21 and 22 are pushed and moved by the main opening 25a portion of the main connecting body 25 in accordance with the reciprocating movement thereof, and reciprocate between a cooling position (right end position) and a heating position (left end position).

Further, the main connecting body 25 has a circular opening 25b formed on the left and right of the main opening 25a, that is, at a position located substantially directly above the outdoor side outlet port C when the main valve element 15 is at the cooling position (right end position), and a circular opening 25C formed at a position located substantially directly above the indoor side outlet port E when the main valve element 15 is at the heating position (left end position).

[ operation of four-way valve body 10 ]

The operation of the four-way valve body 10 having the above-described configuration will be described below.

When the main valve 15 is at the heating position (left end position), when the first working chamber 31 and the discharge-side high-pressure port D are communicated and the second working chamber 32 and the suction-side low-pressure port S are communicated by a direct-acting solenoid valve 50 described later, the high-temperature and high-pressure refrigerant is introduced into the first working chamber 31 and the high-temperature and high-pressure refrigerant is discharged from the second working chamber 32, the pressure of the first working chamber 31 becomes higher than the pressure of the second working chamber 32, and as shown in fig. 1, the first and second pistons 21 and 22 and the main valve 15 move rightward, the second piston 22 abuts against the right end cap member 11B, and the main valve 15 is at the cooling position (right end position).

Thus, in the cooling/heating system 200, a cooling operation (defrosting operation) is performed (described in detail later).

When the main valve element 15 is at the cooling position (right end position) shown in fig. 1, when the second working chamber 32 and the discharge-side high-pressure port D are communicated and the first working chamber 31 and the suction-side low-pressure port S are communicated by a direct-acting solenoid valve 50 described later, the high-temperature and high-pressure refrigerant is introduced into the second working chamber 32 and the high-temperature and high-pressure refrigerant is discharged from the first working chamber 31, the pressure of the second working chamber 32 becomes higher than the pressure of the first working chamber 31, the first and second pistons 21 and 22 and the main valve element 15 move leftward, the first piston 21 abuts against the left end cap member 11A and is locked, and the main valve element 15 is at the heating position (left end position).

Thus, in the cooling/heating system 200, a heating operation is performed (described in detail later).

[ Structure of direct-acting solenoid valve 50 ]

As shown in the enlarged views of fig. 4 (and fig. 6 to 9), the direct-acting solenoid valve 50 as a pilot valve includes a valve housing 52 formed of a straight pipe having an electromagnetic coil 51 fitted and fixed to the outer periphery of the left end side, and a suction member 55, a first spring 56 formed of a compression coil spring, a first plunger 61, a second spring 57 formed of a compression coil spring, and a second plunger 62 are arranged in series in this valve housing 52 in this order from the left end side.

The left end portion of the valve housing 52 is hermetically joined to a flange-shaped portion (outer peripheral stepped portion) of a suction member 55 by welding or the like, and the suction member 55 is screwed and fixed by a bolt 59 to one end side plate-shaped portion of an outer cover 58 having a groove-shaped cross section and covering the electromagnetic coil 51.

The first plunger 61 and the second plunger 62 are formed in a substantially cylindrical shape, and are disposed so as to be slidable in the axial direction (the direction along the center line L of the valve housing 52) in the valve housing 52 along with a first valve body 71 and a second valve body 72 (described later), respectively.

Specifically, the second plunger 62 has; a short cylindrical base portion 62 a; two extending portions 62b, which are fixed to the left end side outer peripheral portion of the base portion 62a at two upper and lower positions and are formed of rectangular flat plate-like members made of the same material as the base portion 62 a. The extending portion 62b is fitted at its right end portion into a cutout portion 62c formed at two upper and lower positions on the outer peripheral portion on the left end side of the base portion 62a, and is joined to the cutout portion 62c by welding or the like, and at its left end portion, it passes through the outer side of the first plunger 61 in the shape of an elongated column and extends to the suction member 55 side (in the axial direction). Grooves 61c, 61c for inserting the two extending portions 62b, 62b (with a slight gap 61s therebetween) are formed in (two places above and below) the outer peripheral portion of the first plunger 61. Although the base portion 62a and the extending portion 62b are formed as separate bodies, it is needless to say that the base portion 62a and the extending portion 62b may be formed integrally, that is, the second plunger 62 having the base portion 62a and the extending portion 62b may be manufactured by integral molding.

The first spring 56 is attached to be compressed between the suction member 55 and the first plunger 61 to bias the first plunger 61 in a direction of separating from the suction member 55, and the second spring 57 is attached to be compressed between (the base portion 62a of) the first plunger 61 and the second plunger 62 to bias the second plunger 62 in a direction of separating from the first plunger 61.

On the right end face of the first plunger 61, a plate-shaped contact preventing member 64 (see fig. 6 for a contact preventing state) is disposed so as to prevent direct contact between (the base portion 62a of) the first plunger 61 and the second plunger 62 in the axial direction (that is, the moving direction), that is, so as to provide a slight gap therebetween, and the contact preventing member 64 is made of a nonmagnetic material such as a synthetic resin. The contact preventing member 64 is clamped by an annular step surface (step surface formed by the large diameter portion 75b and the left end small diameter portion 75A of the left half portion 75A) provided at the middle portion of the first spool holder 75 and a right end surface of the first plunger 61 that is fixed to the left end (left end small diameter portion 75A) of the first spool holder 75 by caulking, and by sandwiching the washer 63 therebetween. The contact preventing member 64 is not limited to the above configuration, and may be configured by attaching a cylindrical member or the like between surfaces that may come into contact with each other.

A stopper member 65 is fitted and fixed to the inner periphery of the valve housing 52 by brazing, welding, caulking, etc., and the stopper member 65 has a first stopper 66 that prevents the first plunger 61 from moving in the right direction and a second stopper 67 that prevents the second plunger 62 from moving in the right direction. As shown in fig. 5A, the stopper member 65 includes: a cylindrical body portion 65 a; and two leg portions 65b, 65b extending from two positions (in the axial direction) in front and rear of the cylindrical body portion 65a, and the cylindrical body portion 65a is fitted into a portion between the second plunger 62 of the valve housing 52 and a valve seat 70 (described later), and is joined and fixed by spot welding or the like (for example, at three positions). As can be more clearly understood from fig. 5B and 5C in addition to fig. 5A, the two leg-shaped portions 65B and 65B pass through the groove 62d formed in (two places in front and rear of) the outer peripheral portion of the second plunger 62, and the left end portions thereof are fitted into the cutout portions 61d formed in two places in front and rear of the outer peripheral portion on the right end side of the first plunger 61. Thus, the left end portions of the two leg portions 65b, 65b serve as a first stopper 66 for abutting and locking the left end surface of the cutout portion 61d of the first plunger 61, and the left end portion of the cylindrical body portion 65a serves as a second stopper 67 for abutting and locking the outer peripheral portion of the right end surface of the second plunger 62.

Further, by the two legs 65b, 65b being fitted in the groove 62d of the second plunger 62 and the cutout 61d of the first plunger 61, the rotational position of the first plunger 61 and the second plunger 62 about the center line L is specified, and the rotation of the first plunger 61 and the second plunger 62 about the center line L is also prevented. That is, the two leg portions 65b, 65b also function as a first rotation limiting member and a second rotation limiting member that limit the rotation of the first plunger 61 and the second plunger 62 about the center line L.

Further, a cutout 65c for fitting the left end lower portion of the valve seat 70 is formed in the right end lower portion of the cylindrical body 65 a.

In addition to the structure in which the stopper member 65 having the first and second stoppers and formed separately from the valve housing 52 is fitted and fixed to the valve housing 52, the stopper member may be formed as the second stopper 67 by forming a stepped portion in the valve housing 52, and a stopper member formed of a straight pipe or the like may be fitted and fixed to a large diameter portion of the valve housing 52 with its right end in contact with the stepped portion, and the left end of the stopper member may be formed as the first stopper 66, or may be formed as the first and second stoppers 66 and 67 at two places in the valve housing 52.

Here, the area of the two extending portions 62b, 62b of the second plunger 62 on the side closer to the suction member 55 (the total area of the two extending portions 62b, 62 b) is set smaller than the area of the first plunger 61 on the side closer to the suction member 55. The biasing force (set load) of the first spring 56 is set to be larger than the biasing force (set load) of the second spring 57. Further, a gap G1 formed between the left end surface of the base portion 62a of the second plunger 62 and the right end surface of the first plunger 61 (the right end surface of the contact preventing member 64 provided at the right end surface of the first plunger 61), and a gap G2 formed between the left end surface of the extending portion 62b of the second plunger 62 and the right end surface of the suction member 55 are set to be substantially the same.

On the other hand, a cap member 66A having a thin tube insertion port (high-pressure introduction port p10) for introducing a high-pressure refrigerant is airtightly attached to the right end opening of the valve housing 52 by welding, brazing, crimping, or the like, and the area surrounded by the cap member 66A, the second plunger 62, and the valve housing 52 serves as the valve chamber 60. In the valve chamber 60, the high-temperature and high-pressure refrigerant is introduced from the discharge-side high-pressure port D through the flexible high-pressure narrow tube #10 airtightly inserted into the narrow tube insertion port (high-pressure introduction port p10) of the cap member 66A.

Further, a valve seat 70 is airtightly joined by brazing or the like between the second plunger 62 of the valve housing 52 and the cap member 66A, and the upper surface of the valve seat 70 is formed as a flat valve seat surface. In the valve seat surface (upper surface) of the valve seat 70, a first port p1, a second port p2, and a third port p3 are provided in this order from the left end side in the longitudinal direction (left-right direction) of the valve housing 52 so as to be spaced apart from each other at predetermined intervals, and a fourth port p4 is provided in the left end surface of the valve seat 70, the first port p1 being connected to the first working chamber 31 of the four-way valve body 10 by a first narrow tube #1, the second port p2 being connected to the suction-side low-pressure port S by a second narrow tube #2, the third port p3 being connected to the second working chamber 32 by a third narrow tube #3, and the fourth port p4 being connected to the suction-side low-pressure port S by a fourth narrow tube # 4. The opening surface of the fourth port p4 is formed as a conical surface.

A sliding type first valve element 71 pushed and pulled by the first plunger 61 is slidably abutted on the valve seat surface of the valve seat 70 so as to switch the communication state among the first port p1, the second port p2, and the third port p3, and a poppet type second valve element 72 pushed and pulled by the second plunger 62 is disposed on the left end surface of the valve seat 70 so as to be spaced apart and close to open and close the fourth port p 4.

The first valve body 71 has a large oval shape in plan view, and a recess 71a is provided in the first valve body 71, and the recess 71a has a size that allows communication between adjacent ports p1 to p2 and p2 to p3 among 3 ports p1 to p3 provided on the seat surface of the valve seat 70. The first spool 71 is connected to the first plunger 61 via a first spool holder 75, and the first spool holder 75 is composed of a stepped left half 75A and a right half 75B having an opening 77 formed therein.

More specifically, the left end small diameter portion 75A of the first spool holder 75 is fixedly connected to the first plunger 61 by means of caulking or the like, the large diameter portion 75B of the left half body 75A of the first spool holder 75 is slidably fitted to the second plunger 62, the base end portion of the right half body 75B of the first spool holder 75 and the base end portion of the plate spring 68 are fixedly connected to each other by means of caulking or the like to the right end plate portion 75c of the left half body 75A, and the plate spring 68 biases the first spool 71 in the thickness direction (vertical direction). A rounded rectangular opening 77 is formed near the right end of the right half 75B of the first valve body holder 75, and the first valve body 71 is fitted in the opening 77 so as to be slidable in the thickness direction. Here, the length of the opening 77 in the width direction and the left-right direction is formed to be substantially the same as the length of the first valve body 71 in the width direction and the left-right direction.

The second spool 72 is formed as a needle valve having: a valve body portion 72a having a conical surface that is distant from and close to the fourth port p 4; and a cylindrical base end portion 72 b. The second valve body 72 is fixed by press-fitting or swaging to a mounting hole formed in the right end surface of the base end portion 62a of the second plunger 62 so as to be connected to the second plunger 62 through the base end portion 72 b.

The direct-acting solenoid valve 50 is attached to the back side of the four-way valve body 10 by a mounting member 69.

Hereinafter, with reference to fig. 10, a description will be given of a relationship between a voltage (current passing/current stopping) applied to the electromagnetic coil 51 and the operation and position of the first plunger 61 and the second plunger 62, and a relationship between the operation and position of the first spool 71 and the second spool 72 that are interlocked with the first plunger 61 and the second plunger 62. Fig. 10 is a list showing the operation and position of each part of the direct-acting solenoid valve 50 in each operating state (A, B, C, C1).

In the initial setting state in which the current supply to the electromagnetic coil 51 is stopped, as shown in fig. 4, the first plunger 61 is in the non-attracting position [ X2] in which it abuts against and is locked to the first stopper 66, and the second plunger 62 is in the non-attracting position [ X4] in which it abuts against and is locked to the second stopper 67, by the biasing forces of the first spring 56 and the second spring 57. Accordingly, the first valve body 71 is located at a right end position (also referred to as an advanced position) where the second port p2 and the third port p3 communicate with each other and the first port p1 is opened in conjunction with the first plunger 61 [ Y2], and the second valve body 72 is located at a closed position (also referred to as an advanced position) where it is pressed against the conical opening surface of the fourth port p4 and closed in conjunction with the second plunger 62 [ Y4] (state classification: a).

In this state, when the voltage V1 is applied to the electromagnetic coil 51, as shown in fig. 6, the first plunger 61 is still at the non-attracting position [ X2] where it abuts against and is locked to the first stopper 66, and the second plunger 62 is at the attracting position [ X3] where it is drawn toward the first plunger 61 against the urging force of the second spring 57. Here, (the left end portion of) the two extending portions 62b, 62b of the second plunger 62 abut against the attraction member 55, but direct contact between the second plunger 62 and the first plunger 61 is prevented by the contact preventing member 64. Accordingly, the first spool 71 is still at the right end position [ Y2], and the second spool 72 is moved in conjunction with the second plunger 62 to an open position (also referred to as a retreated position) [ Y3] in which it is separated from the conical opening surface of the fourth port p4 and opened (state classification: B).

In this state, when a voltage V2 higher than the voltage V1 is applied to the electromagnetic coil 51, as shown in fig. 7, the first plunger 61 is in the attraction (suction) position [ X1] pulled toward the attracted member 55 against the urging force of the first spring 56, but the second plunger 62 is already in the attraction position [ X3] shown in fig. 6 because it is already in contact with and locked to the attracted member 55. Accordingly, the first spool 71 is located at the left end position (sometimes referred to as a retracted position) where the first port p1 and the second port p2 communicate with each other and the third port p3 is opened (sometimes referred to as a retracted position) [ Y1] in association with the first plunger 61, and the second spool 72 is still located at the open position [ Y3] (state classification: C).

In this state, when the voltage V3 lower than the voltages V1 and V2 (that is, V3 < V1 < V2) is applied to the electromagnetic coil 51, since the areas of the two extending portions 62b, 62b of the second plunger 62 on the side closer to the attraction member 55 are set smaller than the areas of the first plunger 61 on the side closer to the attraction member 55, the first plunger 61 is still held at the attraction (attraction) position [ X1] by the attraction force of the attraction member 55, and the second plunger 62 is returned to the non-attraction position [ X4] by the urging force of the second spring 57, as shown in fig. 8. Accordingly, the first valve body 71 is still at the left end position [ Y1], and the second valve body 72 is returned to the closed position [ Y4] (state classification: C1).

On the other hand, in this state, when a voltage V2 higher than the voltage V1 is applied to the electromagnetic coil 51, as shown in fig. 9, the first plunger 61 is held at the attracting (attracting) position [ X1], and the second plunger 62 is held at the attracting position [ X3] where it is drawn toward the first plunger 61 and the (left end portions of the) extending portions 62b, 62b abut against the attracting member 55 against the urging force of the second spring 57. Accordingly, the first valve body 71 is still at the left end position [ Y1], and the second valve body 72 is again at the open position [ Y3] (state classification: C).

After that, when the electromagnetic coil 51 is stopped being energized, the first plunger 61 is returned to the non-attracting position [ X2] by the urging force of the first spring 56, and the second plunger 62 is returned to the non-attracting position [ X4] by the urging force of the second spring 57. Accordingly, the first valve body 71 is returned to the right end position [ Y2], and the second valve body 72 is returned to the closed position [ Y4] (state classification: A).

In the direct-acting solenoid valve 50 of the present embodiment, as described above, the following are formed: according to a voltage applied to the electromagnetic coil 51, the first plunger 61 is in a non-attracting position [ X2] where it abuts against and is locked to the first stopper 66, and an attracting (attracting) position [ X1] where it is drawn toward the attracting member 55 side, the second plunger 62 is in a non-attracting position [ X4] where it abuts against and is locked to the second stopper 67, and an attracting position [ X3] where it is drawn toward the first plunger 61 side and (the left end portion of) the two extending portions 62b, 62b abuts against and is attracted to the attracting member 55, and accordingly, the first valve body 71 is interlocked with the first plunger 61 to be in a right end position (advanced position) [ Y2] where it communicates with the second port p2 and the third port p3, and in a left end position (retracted position) [ Y1] where it communicates with the first port p1 and the second port p2, and the second valve body 72 is interlocked with the second plunger 62 to be in a closed position (advanced position) [ Y4] where it is pressed against and is closed by the opening surface of the fourth port p4, And an open position (retreated position) [ Y3] away from the conical opening surface of the fourth port p4 to open it.

Further, when in the above-described closed position, the second valve body 72 is pressed against the conical opening surface of the fourth port p4 by the biasing force of the second spring 57, and therefore (the left end portion of) the valve seat 70 formed with the fourth port p4 also serves as the second stopper 67A that prevents the rightward movement of the second plunger 62.

[ Overall Structure and operation of four-way selector valve 1 including direct-acting solenoid valve 50 ]

The configuration and operation of the entire four-way switching valve 1 including the direct-acting solenoid valve 50 and the cooling/heating system 200 will be described below.

The four-way selector valve 1 of the present embodiment is characterized by the following: when switching from the defrosting operation (cooling operation) to the heating operation and when switching from the heating operation to the defrosting operation (cooling operation), the second spool 72 of the direct-acting solenoid valve 50 is placed in the open position (retreated position) described above, and the pressure of the main valve chamber 12 of the four-way valve body 10 is gradually reduced to the predetermined pressure P1.

Therefore, as shown in fig. 1, in order to control the voltage applied to the solenoid 51 of the direct-acting solenoid valve 50, a control unit 40 provided with a microcomputer and an operation panel (remote controller) 42 are provided, and a pressure sensor 45 for detecting the pressure of the main valve chamber 12 is provided (for example, on the discharge-side high-pressure port D side), and the control unit 40 detects that the pressure of the main valve chamber 12 is reduced to the predetermined pressure P1 based on a signal obtained from the pressure sensor 45. In addition, although not shown, in addition to the signals from the operation panel 42 and the pressure sensor 45, signals indicating the states of the temperatures of the respective parts and the operation conditions are also supplied to the control unit 40, and the control unit 40 controls the direct-acting solenoid valve 50 (voltage application), the compressor 210 (number of revolutions), the blowers provided in the outdoor heat exchanger 220 and the indoor heat exchanger 230, and the like based on these signals.

The following describes the defrosting operation (cooling operation), the switching from the defrosting operation to the heating operation, and the switching from the heating operation to the defrosting operation in this order with reference to the time chart of fig. 11. In the timing chart of fig. 11, in order to avoid the complexity of the drawing and the description, the case where the mechanical operation of each part with respect to the change in the applied voltage is not delayed is shown.

In the defrosting operation, the refrigerant flows in the same cycle as in the cooling operation, and the operation, position, state, and the like of each portion are the same as in the cooling operation. In addition, since the frequency of switching from the cooling operation to the heating operation and the frequency of switching from the heating operation to the cooling operation are extremely low, the following description will be made by taking the defrosting operation as a representative example.

[ defrosting (refrigerating) operation ]

When the defrosting (cooling) operation is performed, the energization of the electromagnetic coil 51 is stopped. As a result, as shown in fig. 1, 2, and 4, the first plunger 61 is in the non-suction position where it abuts against and is locked to the first stopper 66, and the second plunger 62 is in the non-suction position where it abuts against and is locked to the second stopper 67 by the biasing force of the first spring 56 and the second spring 57, and accordingly, the first valve body 71 is in the right end position where the second port p2 and the third port p3 are communicated, and the second valve body 72 is in the closed position where the fourth port p4 is closed.

When the first valve body 71 is in the right end position and the second valve body 72 is in the closed position, the high-temperature, high-pressure refrigerant on the discharge side of the compressor 210 is introduced into the first working chamber 31 through the discharge side high pressure port D → the high pressure fine tube #10 → the high pressure introduction port p10 → the valve chamber 60 → the first port p1 → the first fine tube #1, and the high-pressure refrigerant in the second working chamber 32 is discharged to the low pressure suction side port S through the third fine tube #3 → the third port p3 → the recessed portion 71a of the first valve body 71 → the second port p2 → the second fine tube #2, and the main valve body 15 moves rightward and assumes the cooling position (right end position).

Thus, the high-temperature and high-pressure refrigerant from the compressor 210 is introduced into the outdoor heat exchanger 220 through the discharge-side high-pressure port D → the main valve chamber 12 → the outdoor-side inlet port C, releases heat therein, and condenses. Thereby, frost adhering to the outdoor heat exchanger 220 is melted and removed. The condensed high-pressure refrigerant is introduced into the expansion valve 260 to be decompressed, the decompressed low-pressure refrigerant is introduced into the indoor heat exchanger 230 to be evaporated by heat exchange with the indoor air, and the low-temperature and low-pressure refrigerant from the indoor heat exchanger 230 is returned to the suction side of the compressor 210 through the indoor side outlet port E → the inside of the main valve 15 → the suction side low-pressure port S.

[ switching from defrosting operation to heating operation ]

When switching from the defrosting operation to the heating operation, the voltage V1 is applied to the electromagnetic coil 51 (time t 1). Accordingly, as shown in fig. 6, the first plunger 61 is still at the non-suction position where it abuts against and is locked by the first stopper 66, the second plunger 62 is at the suction position where it is drawn toward the first plunger 61 against the biasing force of the second spring 57 and (the left end portion of) the extending portions 62b, 62b abut against the suction member 55, and accordingly, the first valve body 71 is still at the right end position, the second valve body 72 is moved leftward to be at the open position, and the fourth port p4 is opened.

When the first spool 71 is still at the right end position and the second spool 72 is at the open position, the first plunger 61, the first spool 71, and the main spool 15 are still at the positions during the defrosting (cooling) operation, and the high-pressure refrigerant introduced into the valve chamber 60 is discharged to the suction-side low-pressure port S through the fourth port p4 → the fourth narrow tube #4, and the pressure of the main valve chamber 12 gradually decreases.

Then, when the pressure of the main valve chamber 12 decreases to the predetermined pressure P1, the control unit 40 detects this in accordance with the signal from the pressure sensor 42 (time t2), and increases the voltage applied to the solenoid 51 from V1 to V2 which is higher than V1 (time t 2). Accordingly, as shown in fig. 7, the second plunger 62 is still at the suction position, the second valve body 72 is still at the open position, and the first plunger 61 is at the suction (suction) position pulled toward the suction member 55, and the first valve body 71 is moved leftward to be at the left end position where the first port p1 and the second port p2 communicate with each other.

When the second valve spool 72 is still in the open position and the first valve spool 71 is in the left end position, the high-temperature, high-pressure refrigerant on the discharge side of the compressor 210 is introduced into the second working chamber 32 through the discharge side high pressure port D → the high pressure fine tube #10 → the high pressure introduction port p10 → the valve chamber 60 → the third port p3 → the third fine tube #3, and the high-pressure refrigerant in the first working chamber 31 is discharged to the low pressure suction side port S through the first fine tube #1 → the first port p1 → the recessed portion 71a of the first valve spool 71 → the second port p2 → the second fine tube #2, so that the main valve body 15 moves leftward to be in the heating position (left end position).

In this case, immediately after voltage V2 is applied to solenoid 51, the pressure of main valve chamber 12 sharply decreases from predetermined pressure P1, and, during the period when voltage V2 is applied to solenoid 51, since second plunger 62 remains at the above-described attraction position and second valve element 72 remains at the above-described open position, the pressure of main valve chamber 12 continues to decrease even further.

Then, when a predetermined time has elapsed from time t2 at which the voltage V2 is applied, the control unit 40 decreases the voltage applied to the electromagnetic coil 51 from V2 to V3 lower than that (time t 3). Accordingly, as shown in fig. 8, the first plunger 61 is kept at the suction (suction) position by the suction force of the suction member 55, the first valve body 71 is kept at the left end position where the first port p1 and the second port p2 communicate with each other, the main valve body 15 is kept at the heating position (left end position), the second plunger 62 is returned to the non-suction position by the biasing force of the second spring 57, and accordingly, the second valve body 72 is returned to the closed position where the fourth port p4 is closed, so that the pressure in the main valve chamber 12 is not further reduced, and is increased from the time point t3 to the pressure during the normal heating operation.

Thereby, switching from the defrosting operation to the heating operation is completed. In addition, voltage V3 is applied to electromagnetic coil 51 as necessary during the heating operation.

[ heating operation ]

During the heating operation, as shown in fig. 3, the high-temperature and high-pressure refrigerant from the compressor 210 is introduced into the indoor heat exchanger 230 through the discharge-side high-pressure port D → the main valve chamber 12 → the indoor-side inlet port E, and is condensed by heat exchange (heating) with the indoor air, and is introduced into the expansion valve 260 as a high-pressure two-phase refrigerant. The high-pressure refrigerant is decompressed by the expansion valve 260, the decompressed low-pressure refrigerant is introduced into the outdoor heat exchanger 220, exchanges heat with outdoor air and evaporates therein, and the low-temperature and low-pressure refrigerant from the outdoor heat exchanger 220 is returned to the intake side of the compressor 210 through the outdoor side inlet port C → the inside of the main valve core 15 → the intake side low-pressure port S.

[ switching from heating operation to defrosting operation ]

On the other hand, when switching from the heating operation to the defrosting operation, the voltage V2 is applied to the electromagnetic coil 51 (time t 4). As a result, as shown in fig. 9, the first plunger 61 remains in the suction (attracting) position, the second plunger 62 is in the suction position in which it is drawn toward the first plunger 61 against the urging force of the second spring 57 and (the left end portion of) the extending portions 62b, 62b come into contact with the suction member 55, and accordingly, the first valve body 71 remains in the left end position, the second valve body 72 moves leftward to be in the open position, and the fourth port p4 is opened.

When the first spool 71 is still at the left end position and the second spool 72 is at the open position, the first plunger 61, the first spool 71, and the main spool 15 are still at the positions during the heating operation, and the high-pressure refrigerant introduced into the valve chamber 60 is discharged to the suction-side low-pressure port S through the fourth port p4 → the fourth narrow tube #4, and the pressure of the main valve chamber 12 gradually decreases.

When the pressure of the main valve chamber 12 decreases to the predetermined pressure P1, the control unit 40 detects the pressure based on the signal from the pressure sensor 42 (time t5) and stops the energization of the solenoid 51. Thus, the first plunger 61 is returned to the non-suction position where it abuts against and is locked to the first stopper 66 and the second plunger 62 is returned to the non-suction position where it abuts against and is locked to the second stopper 67 by the biasing forces of the first spring 56 and the second spring 57, and along with this, the first valve body 71 is in the right end position where the second port p2 and the third port p3 are communicated and the second valve body 72 is returned to the closed position where the fourth port p4 is closed.

In this case, immediately after the energization of the solenoid 51 is stopped, the pressure of the main valve chamber 12 abruptly decreases from the predetermined pressure P1, but the pressure of the main valve chamber 12 does not decrease any further, and starts to increase from the time point t5 to the pressure during the normal defrosting (cooling) operation.

Thus, the switching from the heating operation to the defrosting operation is completed, and the defrosting (cooling) operation without energization is performed as shown in fig. 1, 2, and 4.

[ effects of the direct-acting solenoid valve 50 and the four-way switching valve 1 of the first embodiment ]

As can be understood from the above description, the four-way switching valve provided with the direct-acting solenoid valve 50 of the present embodiment as a pilot valve is configured as follows: when switching from the defrosting operation to the heating operation and when switching from the heating operation to the defrosting operation, the second valve body 72 of the direct-acting solenoid valve 50 is brought into the open position, and the pressure of the main valve chamber 12 is gradually reduced to a predetermined pressure, so that the pressure difference between the high-pressure side and the low-pressure side can be reduced without reducing the frequency of the compressor 210 too much when switching from the heating operation to the defrosting operation and from the defrosting operation to the heating operation, and therefore, the noise can be effectively reduced, the time required for the pressure of the refrigerant to return to the required high pressure can be shortened, and along with this, the time required from the heating operation to the defrosting operation and the time required for the warm air to exit from the indoor heat exchanger 230 can be shortened.

As described above, in the heat pump type cooling and heating system 200 according to the present embodiment, switching from the heating operation to the defrosting operation and from the defrosting operation to the heating operation can be performed quickly while reducing noise, and in addition, the solenoid valve other than the direct-acting solenoid valve 50 is not necessary, so that the cooling operation, the heating operation, and the defrosting operation can be performed with a relatively simple configuration, and therefore, the installation cost and the component cost can be reduced.

In the direct-acting solenoid valve 50 of the present embodiment, the extension portion 62b extending toward the suction member 55 (left end side) through the outside of the first plunger 61 is provided in a part of the outer peripheral portion of the second plunger 62, and the distance between the second plunger 62 and the suction member 55 is reduced, so that the suction force can be generated with a small magnetomotive force, and therefore the magnetic effect is increased, whereby the switching operation of the direct-acting solenoid valve 50 is facilitated when switching from the heating operation to the defrosting operation and from the defrosting operation to the heating operation.

In the direct-acting solenoid valve 50 of the present embodiment, when the second spool 72 is placed in the open position, (the left end portions of) the extending portions 62b, 62b of the second plunger 62 abut against the suction member 55, and the second plunger 62 abuts against and is locked to the suction member 55, so that the switching operation of the direct-acting solenoid valve 50 can be stabilized when switching from the heating operation to the defrosting operation and from the defrosting operation to the heating operation.

Further, in the direct-acting solenoid valve 50 of the present embodiment, since the poppet-type valve body disposed in the fourth port p4 so as to be capable of being separated from and approaching is used as the second valve body 72, and the amount of movement (lift) of the second valve body 72 required for opening and closing the fourth port p4 can be reduced, the direct-acting solenoid valve 50 can be downsized, and the second valve body 72 can be moved smoothly as compared with the direct-acting solenoid valve 80 of the second embodiment (the direct-acting solenoid valve 80 using a slide-type valve body slidably abutting on the fourth port p4 as the second valve body 72) described later. Further, as compared with the direct-acting solenoid valve 80 (the direct-acting solenoid valve 80 provided with the permanent magnet 53) of the second embodiment described later, various effects as follows can be obtained: the number of parts can be reduced; when the voltage is cut off due to a power failure or the like, the position of the first plunger 61 (the first valve body 71 connected to the first plunger 61) can be easily grasped; it is no longer necessary to consider the magnetic balance design of the gap voltage of the first plunger 61, etc., which is necessary when the permanent magnet 53 is used.

[ second embodiment ]

Fig. 12A is a side view showing a rotary four-way switching valve provided with the second embodiment of the direct-acting solenoid valve of the present invention as a pilot valve, and fig. 12B is a top-surface-side layout view showing a cooling position and a heating position of the rotary four-way switching valve provided with the second embodiment of the direct-acting solenoid valve of the present invention as a pilot valve. Fig. 13 is an overall configuration diagram showing a cooling operation (defrosting operation) of the heat pump type air-cooling system incorporating the rotary four-way switching valve shown in fig. 12A and 12B (shown in the cross section X-X of the cooling position in fig. 12B). Fig. 14 is an overall configuration diagram showing a heating operation of the heat pump type air-cooling and heating system incorporating the rotary four-way switching valve shown in fig. 12A and 12B (shown in the X-X cross section of the heating position in fig. 12B). Fig. 16 is an enlarged sectional view showing a partial plan view of the direct-acting solenoid valve of the second embodiment in cooling operation (defrosting operation) as a pilot valve of the four-way switching valve shown in fig. 13.

The four-way switching valve 2 according to the second embodiment is a rotary four-way switching valve, and basically includes a main valve 105 and a single direct-acting solenoid valve 80 as a pilot valve.

[ Structure of the Main valve 105 ]

The main valve 105 has: a cylindrical main valve case 110 partitioning a main valve chamber 115; a main spool 120 rotatably disposed in the main spool chamber 115; and an actuator 107 for rotating the main spool 120, having a first working chamber 111 and a second working chamber 112, which can be changed in volume, for selectively introducing or discharging high-pressure refrigerant.

The main valve housing 110 includes: a cylindrical body portion 110C; an upper valve seat 110A having a thick disc shape fixed to hermetically close the upper surface opening of the body portion 110C; and a lower valve seat 110B having a thick disc shape fixed to hermetically close the lower surface opening of the body 110C, wherein the upper valve seat 110A has a discharge side high pressure port D and an indoor side outlet port E formed of pipe joints and hanging down in the left and right directions, and the lower valve seat 110B has an outdoor side outlet port C and a suction side low pressure port S formed of pipe joints and hanging down in the left and right directions. The ports are provided on the same circumference, and the discharge-side high-pressure port D and the outdoor-side intake port C, and the indoor-side intake port E and the intake-side low-pressure port S are arranged at the same position in plan view. The lower surface of the upper valve seat 110A and the upper surface of the lower valve seat 110B are flat and smooth valve seat surfaces 117, 117.

Further, a body 150 of the actuator 107 is provided in front and rear of the lower surface side of the lower valve seat 110B.

Main poppet 120 is a split structure of the upper and lower halves of a short cylindrical shape. Specifically, the upper half portion is composed of a thick first layer member 121 and a second layer member 122 integrally joined to the lower surface side of the first layer member 121 by welding or the like, and the lower half portion is composed of a thick disc-shaped third layer member 123 and a thick fourth layer member 124 integrally joined to the lower surface side of the third layer member 123 by welding or the like.

The main spool 120 has a spindle portion 130 that is: an upper rotary shaft portion 130A having an angular rod portion that can integrally operate with a main body portion (upper half portion and lower half portion) of the main valve element 120; a lower rotary shaft portion 130B; and round bars 130C, 130C connecting the upper spindle portion 130A and the lower spindle portion 130B. The upper rotary shaft portion 130A is rotatably supported by a bearing hole 116A provided at the center of the lower surface of the upper valve seat 110A, and the lower rotary shaft portion 130B is rotatably supported by a bearing hole 116B provided at the center of the bottom surface of a recessed hole provided at the center of the lower surface of the lower valve seat 110B.

When switching the flow path, the main valve element 120 is rotated in both forward and reverse directions by an actuator 107 described later and a rotary shaft 130, and is formed so as to be selectively positioned: the cooling position shown in fig. 12B and 13; and a heating position shown in fig. 12B and 14 rotated clockwise by 60 degrees from the cooling position.

The main valve body 120 is provided with a linear first communication passage 131 for communicating the discharge side high pressure port D with the outdoor side inlet port C when in the cooling position, and a linear second communication passage 132 for communicating the indoor side inlet port E with the suction side low pressure port S, and is provided with a U-shaped third communication passage 133 for communicating the discharge side high pressure port D with the indoor side inlet port E and a U-shaped fourth communication passage 134 for communicating the outdoor side inlet port C with the suction side low pressure port S when in the heating position.

As described above, in the four-way switching valve 2 of the present embodiment, the main valve body 120 is rotated 60 degrees clockwise from the cooling position, and the flow paths are switched from the ports D-C communicated through the first communication passage 131 to the ports E-S communicated through the second communication passage 132 to the ports D-E communicated through the third communication passage 133 and the ports C-S communicated through the fourth communication passage 134, and the main valve body 120 is rotated 60 degrees counterclockwise from the heating position, and the flow paths are switched in the opposite direction.

In the four-way selector valve 2 of the present embodiment configured as described above, the first communication passage 131 and the second communication passage 132 are formed as straight passages having a thickness (passage diameter) from the start end to the end that is substantially the same as the diameters of the discharge-side high-pressure port D and the indoor-side outlet port E, and the refrigerant flows directly from the discharge-side high-pressure port D and the indoor-side outlet port E to the right below, so that pressure loss in the main valve 105 (main valve element 120) hardly occurs. Further, since the volumes of the U-shaped third and fourth communication passages 133, 134 are formed to be large, the pressure loss is reduced, and the pressure loss can be reduced to a considerable extent as a whole.

[ Structure of actuator 107 ]

Hereinafter, the actuator 107 for rotating the main spool 120 will be described with reference to fig. 15A and 15B.

The actuator 107 is a fluid pressure type actuator utilizing a pressure difference between a high-pressure refrigerant and a low-pressure refrigerant flowing through the main valve 105, and includes a main body 150 provided on one end side (rear end side) of the lower valve seat 110B of the main valve housing 110. The main body 150 includes: a cylindrical body 151; a lower surface closing member 152 having a convex portion 152a at the center; and an upper surface closing member 153 which is thick and disc-shaped and also serves as a sealing member and a stopper, the body portion 151 extending downward from the lower valve seat 110B, the lower surface closing member 152 being fixed and hooped so as to hermetically close the lower surface opening of the body portion 151, the upper surface closing member 153 being hermetically fixed so as to hermetically close the upper surface opening of the body portion 151, a thick bottomed cylindrical pressure receiving movable body 160 and a short cylindrical rotation driving body 165 being housed in the operation chamber 155 thereof, the pressure receiving movable body 160 constituting a motion conversion mechanism 158, and the rotation driving body 165 being relatively rotatably inserted into the pressure receiving movable body 160 in accordance with the vertical movement of the pressure receiving movable body 160. As the pressure receiving movable body 160 moves up and down, the rotary drive body 165 rotates relatively inside the pressure receiving movable body 160.

A gasket 162 is attached near the lower end of the outer periphery of the pressure receiving body 160, and the gasket 162 hermetically seals the inner peripheral surface of the operating chamber 155 and hermetically partitions the operating chamber 155 into the first operating chamber 111 and the second operating chamber 112 whose volumes can be changed. Further, the operation pins 163 are fixed to the upper outer peripheral portion of the pressure receiving movable body 160 by press fitting or the like, and the operation pins 163 are fitted into the key grooves 154 provided at two left and right positions on the upper inner peripheral half portion of the body 151 and extending in the height direction.

The pressure receiving movable body 160 can linearly move up and down but is prevented from rotating by the operation pin 163 and the key groove 154.

An upper port 114 for introducing or discharging the high-pressure refrigerant into or from the second working chamber 112 is provided at an upper portion of the body 150, and a lower port 113 for introducing or discharging the high-pressure refrigerant into or from the first working chamber 111 is provided at a bottom portion (lower surface closing member 152) thereof.

Between the pressure receiving movable body 160 and the rotary drive body 165 constituting the motion conversion mechanism 158, balls 172, receiving portions 174 for the balls 172, and a spiral groove 175 are provided to convert the vertical movement (reciprocating linear motion) of the pressure receiving movable body 160 into the rotary motion of the rotary drive body 165 in both forward and reverse directions.

Specifically, the pressure receiving movable body 160 is provided with a plurality of (2 in the present embodiment) balls 172 and receiving portions 174 thereof, and the rotary drive body 165 is provided with a plurality of (2 in the present embodiment) spiral grooves 175 extending in the vertical direction while being curved in the circumferential direction at the outer periphery thereof. The receiving portion 174 receives the ball 172 in a state in which a part of the ball 172 protrudes radially inward and is rotatably substantially prevented from moving, and the spiral groove 175 is formed of a shallow groove having an arc-shaped cross section into which a part of the ball 172 protruding radially inward from the receiving portion 174 is fitted and rotatably brought into close contact with the shallow groove.

A rotation driving shaft portion 176 is fastened to the center of the rotation driving body 165, and the rotation driving shaft portion 176 rotates integrally with the rotation driving body 165. The rotation drive shaft 176 includes: an eccentric portion 176a having a lower portion fixed to the rotation driving body 165; a stepped large-diameter intermediate portion 176b rotatably supported by the upper surface blocking member 153; a pivot portion 176c having a small diameter and rotatably supported in a bearing hole 119 provided in the lower surface side of the lower valve seat 110B. Further, an O-ring 159 is provided between the central hole of the upper surface closing member 153 and the stepped large-diameter intermediate portion 176 b.

Here, the rotation axis Q of the rotation driver 165 (rotation driving shaft portion 176) is provided in parallel with the rotation axis O of the main valve element 120, and a rocker-arm type rotation transmission mechanism 177 for transmitting the rotation of the rotation driver 165 (rotation driving shaft portion 176) to the main valve element 120 is provided between the rotation driving shaft portion 176 and the lower side rotation shaft portion 130B of the main valve element 120.

In such a configuration, when high-pressure refrigerant is introduced into the first working chamber 111 through the lower port 113 and high-pressure refrigerant is discharged from the second working chamber 112 through the upper port 114, the first working chamber 111 is at a higher pressure than the second working chamber 112, and therefore the pressure receiving movable body 160 is pushed upward, the operation pin 163 of the pressure receiving movable body 160 is guided by the key groove 154, the pressure receiving movable body 160 moves straight upward, and accordingly, the balls 172 of the motion conversion mechanism 158 also move straight upward while rotating. At this time, the spiral groove 175 is pressed in the circumferential direction by the portion of the ball 172 fitted into the spiral groove 175, and the rotary drive body 165 rotates in one direction (clockwise in this case). Then, when the upper end of the pressure receiving movable body 160 comes into contact with the upper surface closing member 153, the upward movement of the pressure receiving movable body 160 is stopped, and the rotation of the rotary drive body 165 is also stopped. Hereinafter, this stroke is referred to as an upward stroke.

On the other hand, in the above-described up-stroke completed state, when high-pressure refrigerant is introduced into the second working chamber 112 through the upper port 114 and high-pressure refrigerant is discharged from the first working chamber 111 through the lower port 113, the second working chamber 112 is at a higher pressure than the first working chamber 111, so that the pressure receiving movable body 160 is pushed down, the operation pin 163 of the pressure receiving movable body 160 is guided by the key groove 154, the pressure receiving movable body 160 moves straight down, and accordingly, the balls 172 of the motion conversion mechanism 158 also move straight down while rotating. At this time, the spiral groove 175 is pressed in the circumferential direction by the portion of the ball 172 fitted into the spiral groove 175, and the rotary drive body 165 rotates in the other direction (here, counterclockwise). Then, when the lower end of the pressure receiving movable body 160 comes into contact with the convex portion 152a of the lower surface blocking member 152, the downward movement of the pressure receiving movable body 160 is stopped, and the rotation of the rotary drive body 165 is also stopped. Hereinafter, this stroke is referred to as a downward stroke.

As described above, in the upward stroke completion state, the pressure receiving movable body 160 is positioned in the downward stroke, whereby the main valve element 120 is rotated from the cooling position to the heating position, and the flow path switching as described above is performed, whereas in the downward stroke completion state, the pressure receiving movable body 160 is positioned in the upward stroke, whereby the main valve element 120 is rotated from the heating position to the cooling position, and the flow path switching as described above is performed.

In the present embodiment, the flow path switching (switching between the cooling position and the heating position), that is, the switching between the up stroke and the down stroke of the actuator 107, is performed by the direct-acting solenoid valve 80, which will be described later, connected to the upper port 114 and the lower port 113, and the discharge-side high-pressure port D, which is a high-pressure portion, and the suction-side low-pressure port S, which is a low-pressure portion.

The above description has been made of the schematic structure of the main valve 105 and the actuator 107 of the rotary four-way switching valve 2, and as for the detailed structure, reference may be made to the specification of japanese patent application No. 2014-252259 and the like filed by the present applicant, if necessary.

[ Structure of direct-acting solenoid valve 80 ]

A second embodiment of the direct-acting solenoid valve according to the present invention will be described below with reference to fig. 16 and 17 to 20.

Since the basic configuration of the direct-acting solenoid valve 80 according to the second embodiment is substantially the same as that of the direct-acting solenoid valve 50 according to the first embodiment, the same reference numerals are given to the portions corresponding to the portions of the direct-acting solenoid valve 50, redundant description is omitted, and the differences will be mainly described below.

The direct-acting solenoid valve 80 as a pilot valve of the present embodiment is basically the same as the direct-acting solenoid valve of the first embodiment in that a suction member 55, a first spring 56 made of a compression coil spring, a first plunger 61, a second spring 57 made of a compression coil spring, and a second plunger 62 are arranged in series in this valve housing 52 from the left end side, but on the left side of the suction member 55, a thick disc-shaped permanent magnet 53 is fastened and fixed together with one end side plate-shaped portion of an outer cover 58 having a groove-shaped cross section covering the electromagnetic coil 51 by a bolt 59 screwed into the suction member 55 with a plate 54 made of a magnetic metal material interposed therebetween.

The permanent magnets 53 are magnetized to have different polarities in the thickness direction, are arranged in series with the attraction member 55, and generate magnetic flux that draws the first plunger 61 and the second plunger 62 toward the attraction member 55.

A stopper member 65 having a slightly longer length in the axial direction (left-right direction) of the cylindrical body portion 65a than that of the first embodiment is fitted and fixed to the inner periphery of the valve housing 52, and the stopper member 65 includes a first stopper 66 that prevents the first plunger 61 from moving rightward and a second stopper 67 that prevents the second plunger 62 from moving rightward.

In the present embodiment, as in the first embodiment, the area of the two extending portions 62b, 62b of the second plunger 62 on the side closer to the suction member 55 (the total area of the two extending portions 62b, 62 b) is set smaller than the area of the first plunger 61 on the side closer to the suction member 55, the biasing force (set load) of the first spring 56 is set larger than the biasing force (set load) of the second spring 57, and the interval G1 between the left end surface of the base portion 62a of the second plunger 62 and the right end surface of the first plunger 61 (the right end surface of the contact preventing member 64 provided on the right end surface of the first plunger 61) and the interval G2 between the left end surface of the extending portion 62b of the second plunger 62 and the right end surface of the suction member 55 are set to be substantially the same.

Further, on the seat surface of the valve seat 70, similarly to the first embodiment, a first port p1, a second port p2, and a third port p3 are provided from one end to the other end in the lateral direction, a fourth port p4 is provided at a longer distance to the right than the third port p3, the first port p1 is connected to the first working chamber 111 of (the actuator 107 of) the main valve 105 through a first narrow tube #1, the second port p2 is connected to the suction-side low-pressure port S through a second narrow tube #2, the third port p3 is connected to the second working chamber 112 through a third narrow tube #3, and the fourth port p4 is connected to the suction-side low-pressure port S through a fourth narrow tube # 4.

Further, a sliding type first valve body 71 pushed and pulled by the first plunger 61 is slidably abutted on the valve seat surface of the valve seat 70 so as to switch the communication state among the first port p1, the second port p2, and the third port p3, and a sliding type second valve body 72 pushed and pulled by the second plunger 62 is slidably abutted on the valve seat surface so as to switch the fourth port p 4.

The first valve body 71 and the connection structure between the first valve body 71 and the first plunger 61 are substantially the same as those of the first embodiment, but here, the second valve body 72 has a shape in which a small and a large elongated semi-ellipsoidal body are combined in a plan view.

In order to connect the second spool 72 and the second spool 62, a left end portion of a second spool holder 76 is fixedly connected to the second spool 62 by means of caulking, welding, or the like, the second spool holder 76 is disposed directly below a first spool holder 75 connecting the first spool 71 and the first spool 61, a right end portion of the second spool holder 76 is positioned to the right of a right end portion of the first spool holder 75, an opening 78 having a rectangular shape with a long and narrow rounded corner and having the same width as the opening 77 of the first spool holder 75 is formed on the right end side of the second spool holder 76, and a pair of locking portions 79 protruding inward in the width direction are provided in the opening 78. The first valve body 71 is fitted to a portion 78A of the opening 78 on the left side of the locking portion 79 so as to be slidable in the left-right direction and the thickness direction. The length of the left portion 78A in the left-right direction is set to a length at which the first valve body 71 does not interfere with the first plunger 61 when reciprocating between the left end position and the right end position.

The second valve body 72 is fitted to the right side portion 78B of the opening 78 with respect to the locking portion 79 so as to be slidable in the left-right direction and the up-down direction, and the size and shape of the opening 78 are set as follows: when the second plunger 62 moves in the right direction, the locking portion 79 presses and moves the second valve body 72 to the right end position, and when the second plunger 62 moves in the left direction, the right end of the opening 78 presses and moves the second valve body 72 to the left end position.

In the present embodiment, the plate spring 68 fixed to the right end plate portion 75c of the left half body 75A of the first valve body holder 75 is connected to the right half body 75B, and biases the second valve body 72 in the thickness direction (vertical direction) together with the first valve body 71.

Hereinafter, with reference to fig. 21, a description will be given of a relationship between a voltage (current passing/current stopping) applied to the electromagnetic coil 51 and the operation and position of the first plunger 61 and the second plunger 62, and a relationship between the operation and position of the first spool 71 and the second spool 72 that are interlocked with the first plunger 61 and the second plunger 62. Fig. 21 is a list showing the operation and position of each part of the direct-acting solenoid valve 80 in each state (A, A1, B, C, C1).

In the initial setting state in which the current supply to the electromagnetic coil 51 is stopped, as shown in fig. 16, the first plunger 61 is in the non-attracting position [ X2] in which it abuts against and is locked to the first stopper 66, and the second plunger 62 is in the non-attracting position [ X4] in which it abuts against and is locked to the second stopper 67, by the biasing forces of the first spring 56 and the second spring 57. Accordingly, the first spool 71 is located at a right end position (advanced position) [ Y2] where the second port p2 and the third port p3 are communicated with each other and the first port p1 is opened in conjunction with the first plunger 61, and the second spool 72 is located at a closed position (advanced position) [ Y4] where the fourth port p4 is closed in conjunction with the second plunger 62 (state classification: a).

In this state, when the voltage V1 is applied to the electromagnetic coil 51, as shown in fig. 17, the first plunger 61 is still at the non-attracting position [ X2] where it abuts against and is locked to the first stopper 66, and the second plunger 62 is at the attracting position [ X3] where it is drawn toward the first plunger 61 against the urging force of the second spring 57. Here, (the left end portion of) the two extending portions 62b, 62b of the second plunger 62 abut against the attraction member 55, but direct contact between the second plunger 62 and the first plunger 61 is prevented by the contact preventing member 64. Accordingly, the first valve body 71 is still at the right end position [ Y2], and the second valve body 72 is moved to an open position (retreated position) [ Y3] in which the fourth port p4 is opened in conjunction with the second plunger 62 (state classification: B).

In this state, when a voltage V2 higher than the voltage V1 is applied to the electromagnetic coil 51, as shown in fig. 18, the first plunger 61 is in an attraction (attracting) position [ X1] pulled toward the attracted member 55 against the urging force of the first spring 56, but the second plunger 62 is already in abutment with and locked to the attracted member 55 and is thus still in the attraction position [ X3] shown in fig. 17. Accordingly, the first spool 71 is in a left end position (retracted position) [ Y1] in which the first port p1 and the second port p2 are communicated and the third port p3 is opened in association with the first plunger 61, and the second spool 72 is still in the above-described open position [ Y3] (state classification: C).

In this state, when the electromagnetic coil 51 is not energized, as shown in fig. 19, the first plunger 61 is held at the attracting (attracting) position [ X1] by the magnetic force of the permanent magnet 53, and the second plunger 62 is returned to the non-attracting position [ X4] by the urging force of the second spring 57 (this state is referred to as a no-energization-locked (latch) state). Accordingly, the first valve body 71 is still at the left end position [ Y1], and the second valve body 72 is returned to the closed position [ Y4] (state classification: C1).

On the other hand, in the current-non-passage blocking state, when the voltage V2 higher than the voltage V1 is applied to the electromagnetic coil 51, as shown in fig. 20, the first plunger 61 is held at the attracting (attracting) position [ X1], and the second plunger 62 is held at the attracting position [ X3] where (the left end portions of) the two extending portions 62b, 62b abut against the attracting member 55 while being drawn toward the first plunger 61 side against the urging force of the second spring 57. Accordingly, the first valve body 71 is still at the left end position [ Y1], and the second valve body 72 is again at the open position [ Y3] (state classification: C).

Thereafter, when the voltage-V2 of the opposite polarity is applied to the electromagnetic coil 51, the magnetic force of the permanent magnet 53 is cancelled, the first plunger 61 is returned to the non-attracting position [ X2] by the urging force of the first spring 56, and the second plunger 62 is returned to the non-attracting position [ X4] by the urging force of the second spring 57. Accordingly, the first valve body 71 is returned to the right end position [ Y2], and the second valve body 72 is returned to the closed position [ Y4] (state classification: A1).

As described above, in the direct-acting solenoid valve 80 of the present embodiment, the following are formed in the same manner as the direct-acting solenoid valve 50 of the first embodiment: according to a voltage applied to the electromagnetic coil 51, the first plunger 61 is in a non-attracting position [ X2] in which it abuts against and is locked to the first stopper 66, and an attracting (attracting) position [ X1] in which it is drawn toward the attracting member 55 side, the second plunger 62 is in a non-attracting position [ X4] in which it abuts against and is locked to the second stopper 67, and an attracting position [ X3] in which it is drawn toward the first plunger 61 side and (the left end portions of) the two extending portions 62b, 62b abut against and are attracted to the attracting member 55, and accordingly, the first valve body 71 is in a right end position (advanced position) [ Y2] in which the second port p2 and the third port p3 are communicated, and in a left end position (retracted position) [ Y1] in which the first port p1 and the second port p2 are communicated, and the second valve body 72 is in a closed position (advanced position) [ Y4] in which the fourth port p4 is closed, in which it is interlocked with the second plunger 62, And an open position (retreated position) [ Y3] to open it.

[ Overall operation of the rotary four-way selector valve 2 including the direct-acting solenoid valve 80 ]

The overall operation of the four-way selector valve 2 including the direct-acting solenoid valve 80 will be described below.

In the four-way switching valve 2 of the present embodiment, as in the first embodiment, when switching from the defrosting operation (cooling operation) to the heating operation and when switching from the heating operation to the defrosting operation (cooling operation), the second valve body 72 of the direct-acting solenoid valve 80 is placed in the open position (retreated position) in which the fourth port P4 is opened, and the pressure of the main valve chamber 115 of the main valve 105 is gradually reduced to the predetermined pressure P1.

The following describes the defrosting operation (cooling operation), the switching from the defrosting operation to the heating operation, and the switching from the heating operation to the defrosting operation in this order with reference to the time chart of fig. 22.

[ defrosting (refrigerating) operation ]

When the defrosting (cooling) operation is performed, the energization of the electromagnetic coil 51 is stopped. As a result, as shown in fig. 16, the first plunger 61 is in the non-suction position where it abuts against and is locked to the first stopper 66 and the second plunger 62 is in the non-suction position where it abuts against and is locked to the second stopper 67 by the biasing forces of the first spring 56 and the second spring 57, and along with this, the first valve body 71 is in the right end position where the second port p2 and the third port p3 are communicated and the second valve body 72 is in the closed position where the fourth port p4 is closed.

When the first valve body 71 is in the right end position and the second valve body 72 is in the closed position, the high-temperature and high-pressure refrigerant on the discharge side of the compressor 210 is introduced into the first working chamber 111 through the discharge side high pressure port D → the high pressure fine tube #10 → the high pressure introduction port p10 → the valve chamber 60 → the first port p1 → the first fine tube #1, and the high-pressure refrigerant in the second working chamber 112 is discharged to the low pressure suction side port S through the third fine tube #3 → the third port p3 → the recessed portion 71a of the first valve body 71 → the second port p2 → the second fine tube #2, so that the pressure receiving movable body 160 is positioned in the upward stroke, and the main valve body 120 is rotated 60 degrees counterclockwise to be positioned in the cooling position.

Thus, as shown in fig. 13, the high-temperature and high-pressure refrigerant from the compressor 210 is introduced into the outdoor heat exchanger 220 through the discharge-side high-pressure port D → the first communication passage 131 → the outdoor-side inlet port C, releases heat therein, and condenses. Thereby, frost adhering to the outdoor heat exchanger 220 is melted and removed. The condensed high-pressure refrigerant is introduced into the expansion valve 260 to be decompressed, the decompressed low-pressure refrigerant is introduced into the indoor heat exchanger 230, and is evaporated by heat exchange with the indoor air, and the low-temperature and low-pressure refrigerant from the indoor heat exchanger 230 is returned to the suction side of the compressor 210 through the indoor side inlet port E → the second communication passage 132 → the suction side low-pressure port S.

[ switching from defrosting operation to heating operation ]

When switching from the defrosting operation to the heating operation, the voltage V1 is applied to the electromagnetic coil 51 (time t 1). Accordingly, as shown in fig. 17, the first plunger 61 is still at the non-suction position where it abuts against and is locked by the first stopper 66, the second plunger 62 is at the suction position where it is drawn toward the first plunger 61 and (the left end portion of) the extending portions 62b, 62b abut against the suction member 55 against the urging force of the second spring 57, and accordingly, the first valve body 71 is still at the right end position, the second valve body 72 is moved leftward to be at the open position, and the fourth port p4 is opened.

When the first spool 71 is still at the right end position and the second spool 72 is at the open position, the first plunger 61, the first spool 71, and the main spool 120 are still at the positions during the defrosting (cooling) operation, and the high-pressure refrigerant introduced into the valve chamber 60 is discharged to the suction-side low-pressure port S through the fourth port p4 → the fourth narrow tube #4, and the pressure of the main spool 115 gradually decreases.

Then, if the pressure of the main valve chamber 115 decreases to the predetermined pressure P1, the voltage applied to the solenoid 51 is increased from V1 to V2 higher than it (time point t 2). In the present embodiment, the pressure of the main valve chamber 115 is reduced to the predetermined pressure P1, and can be detected based on a signal from a pressure sensor for detecting the pressure of the main valve chamber 115.

Accordingly, as shown in fig. 18, the second plunger 62 is still at the suction position, the second valve body 72 is still at the open position, and the first plunger 61 is at the suction (suction) position pulled toward the suction member 55, and the first valve body 71 is moved leftward to be at the left end position where the first port p1 and the second port p2 communicate with each other.

When the second valve spool 72 is still in the open position and the first valve spool 71 is in the left end position, the high-temperature, high-pressure refrigerant on the discharge side of the compressor 210 is introduced into the second working chamber 112 through the discharge side high pressure port D → the high pressure fine tube #10 → the high pressure introduction port p10 → the valve chamber 60 → the third port p3 → the third fine tube #3, and the high-pressure refrigerant in the first working chamber 111 is discharged to the low pressure intake side port S through the first fine tube #1 → the first port p1 → the recessed portion 71a of the first valve spool 71 → the second port p2 → the second fine tube #2, so that the pressure receiving movable body 160 is positioned in the downward stroke, and the main valve body 120 is rotated 60 degrees in the clockwise direction to be positioned in the heating position.

In this case, immediately after the voltage V2 is applied to the solenoid 51, the pressure of the main valve chamber 115 sharply decreases from the predetermined pressure P1, and, during the period when the voltage V2 is applied to the solenoid 51, since the second plunger 62 remains at the above-described attraction position and the second spool 72 remains at the above-described open position, the fourth port P4 remains open, and the pressure of the main valve chamber 115 continues to decrease even further.

Then, when a predetermined time elapses from time t2 at which the voltage V2 is applied, the current is stopped from being supplied to the electromagnetic coil 51 (time t 3). Accordingly, as shown in fig. 19, the first plunger 61 is still held at the above-described attracted (attracted) position (non-energized and locked state) by the magnetic force of the permanent magnet 53, the first spool 71 is still at the left end position where the first port p1 and the second port p2 communicate with each other, the main spool 120 is still at the heating position, the second plunger 62 is returned to the non-attracted position by the biasing force of the second spring 57, and accordingly, the second spool 72 is returned to the closed position where the fourth port p4 is closed, so that the pressure in the main valve chamber 115 does not further decrease, and rises from the time point t3 to the pressure during the normal heating operation.

Thus, the switching from the defrosting operation to the heating operation is completed, and the heating operation is performed in the non-energization shut-off state.

[ heating operation ]

During the heating operation, as shown in fig. 14, the high-temperature and high-pressure refrigerant from the compressor 210 is introduced into the indoor heat exchanger 230 through the discharge-side high-pressure port D → the third communication passage 133 → the indoor-side inlet port E, is condensed by heat exchange (heating) with the indoor air, is changed into a high-pressure two-phase refrigerant, and is introduced into the expansion valve 260. The high-pressure refrigerant is decompressed by the expansion valve 260, the decompressed low-pressure refrigerant is introduced into the outdoor heat exchanger 220, exchanges heat with outdoor air and evaporates therein, and the low-temperature and low-pressure refrigerant from the outdoor heat exchanger 220 is returned to the suction side of the compressor 210 through the outdoor side inlet port C → the fourth communication passage 134 → the suction side low-pressure port S.

[ switching from heating operation to defrosting operation ]

On the other hand, when switching from the heating operation to the defrosting operation, the voltage V2 is applied to the electromagnetic coil 51 (time t 4). As a result, as shown in fig. 20, the first plunger 61 is still at the suction (attracting) position, the first valve body 71 is still at the left end position, the second plunger 62 is at the suction position where it is drawn toward the first plunger 61 and (the left end of) the extending portions 62b, 62b abut against the suction member 55 against the urging force of the second spring 57, and as a result, the second valve body 72 moves leftward to be at the open position, and the fourth port p4 is opened.

When the first spool 71 is still at the left end position and the second spool 72 is at the open position, the first plunger 61, the first spool 71, and the main spool 120 are still at the positions during the heating operation, and the high-pressure refrigerant introduced into the valve chamber 60 is discharged to the suction-side low-pressure port S through the fourth port p4 → the fourth narrow tube #4, and the pressure of the main valve chamber 115 gradually decreases.

Then, if the pressure of the main valve chamber 115 decreases to the predetermined pressure P1, a voltage of opposite polarity — V2 is applied to the solenoid 51 (time point t 5).

As a result, the magnetic force of the permanent magnet 53 is cancelled, and the first plunger 61 is returned to the non-attracting position in which it abuts against and is locked to the first stopper 66, and the second plunger 62 is returned to the non-attracting position in which it abuts against and is locked to the second stopper 67 by the biasing forces of the first spring 56 and the second spring 57, and along with this, the first valve body 71 is at the right end position in which the second port p2 and the third port p3 are communicated, and the second valve body 72 is returned to the closed position in which the fourth port p4 is closed.

In this case, immediately after the voltage-V2 is applied to the solenoid 51, the pressure of the main valve chamber 115 abruptly drops from the predetermined pressure P1, but the pressure of the main valve chamber 115 does not drop any further, and rises from the time point t5 to the pressure during the normal defrosting (cooling) operation.

When a predetermined time has elapsed from time t5, the energization of the electromagnetic coil 51 is stopped (time t 6). Thus, the switching from the heating operation to the defrosting operation is completed, and the defrosting (cooling) operation is performed without supplying electricity.

[ effects of the direct-acting solenoid valve 80 and the four-way switching valve 2 of the second embodiment ]

As can be understood from the above description, the rotary four-way switching valve 2 provided with the direct-acting solenoid valve 80 of the second embodiment as a pilot valve is also configured such that: since the second valve body 72 of the direct-acting solenoid valve 80 is set to the open position and the pressure of the main valve chamber 115 is gradually reduced to the predetermined pressure when switching from the defrosting operation to the heating operation and when switching from the heating operation to the defrosting operation, the pressure difference between the high pressure side and the low pressure side can be reduced without reducing the frequency of the compressor 210 too much when switching from the heating operation to the defrosting operation and from the defrosting operation to the heating operation, and therefore, the noise can be effectively reduced, the time required for the pressure of the refrigerant to return to the required high pressure can be shortened, and accordingly, the time required from the heating operation to the defrosting operation and the time required for the warm air to exit from the indoor heat exchanger 230 can be shortened.

As described above, in the heat pump type cooling and heating system 200 according to the present embodiment, switching from the heating operation to the defrosting operation and from the defrosting operation to the heating operation can be performed quickly while reducing noise, and further, the solenoid valve other than the direct-acting solenoid valve 80 is not necessary, so that the cooling operation, the heating operation, and the defrosting operation can be performed with a relatively simple configuration, and therefore, the installation cost and the component cost can be reduced.

Further, since the direct-acting solenoid valve 80 is formed as a self-holding type solenoid valve in which the permanent magnet 53 is provided, it is possible to stop the energization of the electromagnetic coil 51 during the cooling operation (defrosting operation) and during the heating operation, thereby saving energy.

In the case where the direct-acting solenoid valve 80 is a self-holding type solenoid valve, when it is not clear whether the first plunger 61 is located at the attracting position or the non-attracting position to be attracted by the attracting member 55 due to a power failure, the operation may be restarted, or the voltage V2 may be applied to the electromagnetic coil 51 to first place the first plunger 61 at the attracting (attracting) position, or the like, and the normal operation control may be restarted after the position is grasped.

In the direct-acting solenoid valve 80 of the present embodiment, the extension portion 62b extending toward the suction member 55 (left end side) through the outside of the first plunger 61 is provided in a part of the outer peripheral portion of the second plunger 62, and the distance between the second plunger 62 and the suction member 55 is reduced, so that the suction force can be generated with a small magnetomotive force, and therefore the magnetic effect is increased, whereby the switching operation of the direct-acting solenoid valve 80 is facilitated when switching from the heating operation to the defrosting operation and from the defrosting operation to the heating operation.

In the direct-acting solenoid valve 80 of the present embodiment, when the second spool 72 is placed in the open position, (the left end portions of) the extending portions 62b, 62b of the second plunger 62 abut against the suction member 55, and the second plunger 62 abuts against and is locked by the suction member 55, so that the switching operation of the direct-acting solenoid valve 80 can be stabilized when switching from the heating operation to the defrosting operation and from the defrosting operation to the heating operation.

In the above-described embodiment, the first embodiment in which the direct-acting solenoid valve 50 is used as the pilot valve of the sliding-type four-way switching valve 1 and the second embodiment in which the direct-acting solenoid valve 80 having a different configuration from the direct-acting solenoid valve 50 is used as the pilot valve of the rotary-type four-way switching valve 2 are shown, but the direct-acting solenoid valve 50 may be used as the pilot valve of the rotary-type four-way switching valve 2, or the direct-acting solenoid valve 80 may be used as the pilot valve of the sliding-type four-way switching valve 1, and thus, it is not necessary to describe this.

In the above embodiment, the permanent magnet 53 (and the plate 54 made of a magnetic material) is omitted from the direct-acting solenoid valve 50 using the poppet-type second spool, and the permanent magnet 53 is provided in the direct-acting solenoid valve 80 using the slide-type second spool, but the non-energized closed state may be created by using the permanent magnet in the direct-acting solenoid valve 50 using the poppet-type second spool, or the permanent magnet may be omitted from the direct-acting solenoid valve 80 using the slide-type second spool, and the same state as the non-energized closed state may be created by applying the voltage V3 lower than the voltage V2 to the electromagnetic coil 51, the voltage V2 being a voltage at which the first plunger 61 is held at the attraction (attraction) position (the second plunger 62 is returned to the non-attraction position by the biasing force of the second spring 57).

Claims (22)

1. A direct-acting solenoid valve, characterized by being formed in the following manner:

a valve housing having an electromagnetic coil fixed to an outer periphery of one end side thereof, a suction member, a first plunger, and a second plunger arranged in series in this order from one end side, an extension portion extending to the suction member side through an outer side of the first plunger is provided in a part of the second plunger, an area of the extension portion on a side close to the suction member is formed smaller than an area of the first plunger on a side close to the suction member, a main port is provided on the valve housing on a side closer to the second plunger than the other end side, a valve seat having first, second, third, and fourth ports is provided, a first valve element linked to the first plunger is slidably abutted to switch a communication state between the first, second, and third ports, and a second valve element linked to the second plunger is slidably abutted to switch the fourth port or disposed to be distant from and close to the second port And two spools, the first plunger and the first spool and the second plunger and the second spool being independently located at a plurality of positions, respectively, according to a voltage applied to the electromagnetic coil.

2. A direct-acting solenoid valve, characterized by being formed in the following manner:

a valve housing having an electromagnetic coil fitted and fixed to an outer periphery of one end side, a suction member, a first spring formed of a compression coil spring, a first plunger, a second spring formed of a compression coil spring, and a second plunger arranged in series in this order from the one end side, wherein an extension portion extending to the suction member side through an outer side of the first plunger is provided in a part of the second plunger, an area of the extension portion on the suction member side is formed smaller than an area of the first plunger on the suction member side, and a first stopper and a second stopper are provided to prevent the first plunger and the second plunger from moving to the other end side,

a high-pressure introduction port, a valve seat having first, second, and third ports, and a fourth port, the valve seat being provided with a sliding type first valve element that is pushed and pulled by the first plunger and slidably abutted on the valve seat so as to switch a communication state between the first, second, and third ports, and a sliding type second valve element that is pushed and pulled by the second plunger and slidably abutted on the valve seat so as to switch the fourth port, or a poppet type second valve element that is disposed so as to be capable of being moved away from and close to the valve seat,

the first plunger and the second plunger are respectively in an attracting position and a non-attracting position according to a voltage applied to the electromagnetic coil, the first spool is interlocked with the first plunger to be in one end position at which the first port and the second port are communicated and in the other end position at which the second port and the third port are communicated, and the second spool is interlocked with the second plunger to be in an open position at which the fourth port is opened and a closed position at which the fourth port is closed.

3. Direct-acting solenoid valve according to claim 2,

the extension portion is inserted into a groove formed in an outer peripheral portion of the first plunger.

4. Direct-acting solenoid valve according to claim 2,

one end of a first valve element holder is connected and fixed to the first plunger, one end of the first valve element holder is slidably fitted to the second plunger, and the first valve element is connected, fitted, or engaged to the first plunger so as to be located at the one end position and the other end position in an interlocking manner with the first plunger at the other end of the first valve element holder.

5. Direct-acting solenoid valve according to claim 4,

the valve seat is transversely provided with the first, the second and the third ports and a fourth port from one end to the other end,

a second spool holder is connected and fixed to the second plunger, the second end of the second spool holder being positioned on the other end side of the second end of the first spool holder, and the second spool of the slide type is connected, fitted, or engaged with the second plunger so as to be positioned at the open position and the closed position while interlocking with the second plunger on the other end side of the second spool holder.

6. Direct-acting solenoid valve according to claim 4,

the first, second and third ports are provided in the valve seat in a lateral direction from one end to the other end, and the fourth port is provided at one end surface of the valve seat,

the second poppet is linked to the second plunger and connected, fitted, or engaged so as to be in the open position and the closed position.

7. Direct-acting solenoid valve according to claim 2,

in order to prevent direct contact between the first plunger and the second plunger, a contact preventing member made of a nonmagnetic material is installed therebetween.

8. Direct-acting solenoid valve according to claim 2,

the biasing force of the first spring is set to be larger than the biasing force of the second spring.

9. A direct-acting solenoid valve as claimed in claim 2, characterized by being formed in the following manner:

in a state where the electromagnetic coil is stopped from being energized, the first plunger is in a non-attracting position where the first stopper is in abutment with and locked to the first plunger and the second plunger is in a non-attracting position where the second stopper is in abutment with and locked to the second plunger, whereby the first valve body is in the other end position and the second valve body is in the closed position,

in this state, when a first voltage is applied to the electromagnetic coil, the first plunger is still in a non-attracting position in which the first stopper is in abutment with the first stopper, the second plunger is in an attracting position in which the second plunger is drawn toward the first plunger and the extending portion is in abutment with the attracting member against the urging force of the second spring, and thus the first valve element is still in the other end position and the second valve element is in the open position,

in this state, when a second voltage higher than the first voltage is applied to the electromagnetic coil, the first plunger is in an attraction position drawn by the attraction member against the urging force of the first spring, but the second plunger is still in the attraction position, so that the first valve element is in the one end position and the second valve element is still in the open position,

in this state, when a third voltage lower than the first and second voltages is applied to the electromagnetic coil, the first plunger is held at the attraction position by the attraction force of the attraction member, and the second plunger is returned to the non-attraction position by the urging force of the second spring, so that the first valve element remains at the one end position and the second valve element is returned to the closed position.

10. A direct-acting solenoid valve as claimed in claim 9, formed in the following manner:

in a state where the third voltage is applied to the electromagnetic coil, the first plunger is held at the attracting position by the attracting force of the attracting member, and the second plunger is also held at the non-attracting position, when the second voltage is applied to the electromagnetic coil, the first plunger is held at the attracting position, the second plunger is held at the attracting position in which the second plunger is drawn toward the first plunger side against the urging force of the second spring and the extending portion abuts against the attracting member, whereby the first valve body is held at the one end position and the second valve body is held at the open position,

then, when the electromagnetic coil is stopped from being energized, the first plunger is returned to the non-attracting position by the urging force of the first spring, and the second plunger is returned to the non-attracting position by the urging force of the second spring, whereby the first valve element is returned to the other end position, and the second valve element is returned to the closed position.

11. Direct-acting solenoid valve according to claim 2,

a permanent magnet is disposed on one end side of the valve housing of the attraction member.

12. A direct-acting solenoid valve as claimed in claim 11, formed in the following manner:

in a state where the electromagnetic coil is stopped from being energized, the first plunger is in a non-attracting position where the first stopper is in abutment with and locked to the first plunger and the second plunger is in a non-attracting position where the second stopper is in abutment with and locked to the second plunger, whereby the first valve body is in the other end position and the second valve body is in the closed position,

in this state, when a first voltage is applied to the electromagnetic coil, the first plunger is still in a non-attracting position in which the first stopper is in abutment with the first stopper, the second plunger is in an attracting position in which the second plunger is drawn toward the first plunger and the extending portion is in abutment with the attracting member against the urging force of the second spring, and thus the first valve element is still in the other end position and the second valve element is in the open position,

in this state, when a second voltage higher than the first voltage is applied to the electromagnetic coil, the first plunger is in an attraction position drawn by the attraction member against the urging force of the first spring, but the second plunger is still in the attraction position, so that the first valve element is in the one end position and the second valve element is still in the open position,

in this state, when the electromagnetic coil is not energized, the first plunger is held at the attraction position by the magnetic force of the permanent magnet, and the second plunger is returned to the non-attraction position by the biasing force of the second spring, so that the first valve element is still at the one-end position and the second valve element is returned to the closed position.

13. A direct-acting solenoid valve as claimed in claim 12, formed in the following manner:

in a state where the current supply to the electromagnetic coil is stopped, the first plunger is still held at the attraction position by the magnetic force of the permanent magnet, and the second plunger is also still at the non-attraction position, when the second voltage is applied to the electromagnetic coil, the first plunger is still held at the attraction position, the second plunger is in an attraction position where the second plunger is drawn toward the first plunger side against the urging force of the second spring and the extension portion abuts against the attraction member, whereby the first valve body is still at the one end position, and the second valve body is still at the open position,

then, when a third voltage having an opposite polarity is applied to the electromagnetic coil, the magnetic force of the permanent magnet is cancelled, the first plunger is returned to the non-attracting position by the biasing force of the first spring, and the second plunger is returned to the non-attracting position by the biasing force of the second spring, whereby the first valve element is returned to the other end position, and the second valve element is returned to the closed position.

14. Direct-acting solenoid valve according to claim 2,

the first stopper and the second stopper are each composed of a stopper member disposed and fixed on an inner periphery of the valve housing, a step portion provided in the valve housing, and a part of the valve seat.

15. A four-way switching valve of a sliding type for switching a refrigerant flow direction used in a heat pump type cooling and heating system configured to be capable of selecting a cooling operation, a heating operation, and a defrosting operation in which a refrigerant flows in the same direction as in the cooling operation, the four-way switching valve being configured to:

the direct-acting solenoid valve according to any one of claims 2 to 14 is provided as a pilot valve, and a cylinder-type four-way valve body is provided,

in the four-way valve body, a first working chamber, a first piston, a main valve chamber, a second piston and a second working chamber are sequentially arranged from one end side, a discharge side high pressure port connected with a discharge side of a compressor is arranged in the main valve chamber, a main valve seat is arranged, an outdoor side inlet port connected with an outdoor heat exchanger, a suction side low pressure port connected with a suction side of the compressor and an indoor side inlet port connected with an indoor heat exchanger are sequentially arranged from one end side on a valve seat surface of the main valve seat, a main valve core with an inverted bowl-shaped section is butted in a sliding manner, the main valve core can be selectively positioned at a refrigerating position where the outdoor side inlet port is opened and the outdoor side inlet port is communicated with the indoor side inlet port, and a heating position where the indoor side inlet port is opened and the outdoor side inlet port is communicated with the indoor side inlet port,

the high pressure introduction port of the direct-acting solenoid valve is connected to the discharge-side high pressure port, the first port is connected to the first working chamber, the second port is connected to the suction-side low pressure port, the third port is connected to the second working chamber, and the fourth port is connected to the suction-side low pressure port,

when switching from the defrosting operation to the heating operation and when switching from the heating operation to the defrosting operation, the second spool of the direct-acting solenoid valve is brought to an open position in which the fourth port is opened, and the pressure of the main valve chamber can be reduced to a predetermined pressure.

16. The four-way switching valve of claim 15,

the first piston and the second piston are integrally movably connected to each other by a main connection body, and the main valve body is connected, fitted, or engaged to the main connection body so as to reciprocate between the cooling position and the heating position in accordance with the reciprocating movement of the first and second pistons.

17. The four-way switching valve of claim 15,

a one-end-side cap member serving as a stopper for stopping the first piston from moving in the one-end direction is fixed to one end of the four-way switching valve, and a other-end-side cap member serving as a stopper for stopping the second piston from moving in the other-end direction is fixed to the other end of the four-way switching valve.

18. A four-way switching valve of a rotary type for switching a refrigerant flow direction used in a heat pump type cooling and heating system configured to be capable of selecting a cooling operation, a heating operation, and a defrosting operation in which a refrigerant flows in the same direction as in the cooling operation, the four-way switching valve being configured in such a manner that:

the direct-acting solenoid valve according to any one of claims 2 to 14 is provided as a pilot valve, and a main valve is provided, the main valve including: a cylindrical main valve box for dividing the main valve chamber; a main valve element rotatably disposed in the main valve chamber; and an actuator for rotating the main spool, having a first working chamber and a second working chamber of variable volume selectively introducing or discharging a high-pressure refrigerant,

the main valve box is provided with a discharge side high pressure port connected to a discharge side of the compressor, an outdoor side outlet port connected to an outdoor heat exchanger, a suction side low pressure port connected to a suction side of the compressor, and an indoor side outlet port connected to an indoor heat exchanger, and switches between communication ports by controlling introduction or discharge of a high pressure refrigerant into or from the first working chamber and the second working chamber and rotating the main valve core, thereby switching from a cooling operation or a defrosting operation to a heating operation and from the heating operation to the cooling operation or the defrosting operation,

the high pressure introduction port of the direct-acting solenoid valve is connected to the discharge-side high pressure port, the first port is connected to the first working chamber, the second port is connected to the suction-side low pressure port, the third port is connected to the second working chamber, and the fourth port is connected to the suction-side low pressure port,

when switching from the defrosting operation to the heating operation and when switching from the heating operation to the defrosting operation, the second spool of the direct-acting solenoid valve is brought to an open position in which the fourth port is opened, and the pressure of the main valve chamber can be reduced to a predetermined pressure.

19. The four-way switching valve of claim 18,

the upper and lower valve seats, which hermetically seal the upper and lower surface openings of the main valve housing, are provided with the discharge-side high-pressure port, the outdoor-side inlet/outlet port, the suction-side low-pressure port, and the indoor-side inlet/outlet port.

20. The four-way switching valve according to any one of claims 15 to 19, formed in the following manner:

a control unit for controlling application of a voltage to the solenoid coil of the direct-acting solenoid valve, wherein when switching from the defrosting operation to the heating operation, the control unit first applies a first voltage to the solenoid coil to set the second spool to the open position, and thereby applies a second voltage higher than the first voltage to the solenoid coil after the pressure of the main valve chamber is reduced to the predetermined pressure, and applies a third voltage lower than the second voltage to the solenoid coil after the first spool is set to the one end position,

on the other hand, when switching from the heating operation to the defrosting operation, the second voltage is applied to the solenoid coil to set the second spool to the open position, and thus, the energization of the solenoid coil is stopped after the pressure of the main valve chamber is reduced to the predetermined pressure, and the first spool is set to the other end position.

21. The four-way switching valve according to any one of claims 15 to 19, formed in the following manner:

a control unit for controlling application of a voltage to the solenoid coil of the direct-acting solenoid valve, wherein when switching from the defrosting operation to the heating operation, the control unit first applies a first voltage to the solenoid coil to set the second spool to the open position, and thereby, after the pressure of the main valve chamber is reduced to the predetermined pressure, a second voltage higher than the first voltage is applied to the solenoid coil, and after the first spool is set to the one end position, energization of the solenoid coil is stopped,

on the other hand, when switching from the heating operation to the defrosting operation, the second voltage is applied to the solenoid to set the second spool in the open position, and then a third voltage having an opposite polarity is applied to the solenoid after the pressure of the main valve chamber is reduced to the predetermined pressure, and then the current supply to the solenoid is stopped after the first spool is set in the other end position.

22. The four-way switching valve of claim 20,

equipped with a pressure sensor for detecting a pressure of the main valve chamber, the control portion is formed to: detecting a decrease in pressure of the main valve chamber to the predetermined pressure based on a signal derived from the pressure sensor.

Images