JPH0311667Y2 - - Google Patents

Description

[Detailed explanation of the idea] (Industrial application field) This invention relates to an electric expansion valve.

(Prior Art) An air conditioner is known that defrosts gas refrigerant discharged from a compressor to an outdoor heat exchanger during heating operation, and also has an expansion function and the bypass function. Electric expansion valves having both functions are also known, as described, for example, in Japanese Patent Application Laid-Open No. 60-29560. An example of a refrigerant circuit using this electric expansion valve is shown in FIG. 5. In the figure, 51 indicates an indoor heat exchanger, and 52 indicates an outdoor heat exchanger.
They are connected in parallel by a liquid pipe 53 and a gas pipe 54. The liquid pipe 53 is provided with an electric expansion valve 5.
5, a four-way switching valve 56 is provided in each of the gas pipes 54, and a compressor 57 is connected to the four-way switching valve 56. In this case, compressor 5
The refrigerant discharged from 7 flows from the indoor heat exchanger 51 to the first passage 58 of the electric expansion valve 55, and then the reduced pressure liquid refrigerant flows from the second passage 59 to the outdoor heat exchanger 52, and then, The flow is such that the flow is returned to the compressor 57. In addition, the discharge pipe 60 of the compressor 57 and the third
A bypass pipe 62 is connected to the passage 61 . On the other hand, in the electric expansion valve 55, a first valve body 63 for opening and closing the flow path between the first passage 58 and the second passage 59, and a first valve body 63 for opening and closing the flow passage between the first passage 58 and the second passage 59, A second valve body 64 for opening and closing the flow path between the two valve bodies 63 and 64 is arranged coaxially in the upper and lower positions, that is, the drive shaft 6 of the first valve body 63
5 is disposed so as to pass through the axial center of the second valve body 64. And in the above electric expansion valve,
Normally, an expansion action is performed between the first passage 58 and the second passage 59 by raising and lowering the first valve body 63 using the electric drive mechanism 66, while when performing a defrosting operation. By further raising the first valve body 63 by the drive mechanism 66, the second valve body 64 is pulled up, and the high pressure gas refrigerant from the third passage 61 is supplied to the second passage 59.

(Problem to be solved by the invention) By the way, in the electric expansion valve mentioned above, the third
The pressure of the high-pressure gas refrigerant in the passage 61 always acts on the second valve body 64 in the valve closing direction. There is a drawback that a large force is required to open the valve body 64, and therefore, the electric drive mechanism 66 must have a large output. Furthermore, as described above, since the driving shaft 65 is passed through the axial center of the second valve body 64, the high-pressure gas refrigerant in the third passage 61 is
There is also a problem that leakage occurs from this penetrating portion to the second passage 59, resulting in a loss of heating capacity.

This invention was made in order to solve the above-mentioned drawbacks of the conventional technology, and its purpose was to reduce the opening force during defrosting operation, thereby making it possible to downsize the electric drive mechanism. An object of the present invention is to provide an electric expansion valve that can prevent loss of heating capacity.

(Means for solving the problem) Therefore, in the electric expansion valve of this invention, when the heat exchanger on the user side is heated, the first passage 2 serves as an inlet for high-pressure liquid refrigerant, and the second passage serves as an outlet for the refrigerant. aisle 3
and a third passage 4 serving as an inlet for high-pressure liquid refrigerant or high-pressure gas refrigerant are respectively bored in the valve body 1, and the first passage 2 and the second passage 3 are communicated via a pressure equalizing passage 5. , the third passage 4 and the second passage 3 are communicated via a second passage 6, and inside the second passage 6 there is an opening that is approximately the same as the opening on the first passage side of the pressure equalization passage 5. A second valve seat 8 of caliber is provided. On the other hand, a second valve body 9 is slidably disposed within the valve body 1, and the second valve body 9 contacts and separates from the second valve seat 8 to open the second flow path 6. A valve portion 9b that opens and closes, and a pressure equalizing portion 9a that closes the pressure equalizing path 5 when the valve portion 9b is in contact with the second valve seat 8 are provided, and the second valve body 9 is A biasing means 27 biases the valve in the valve closing direction. Furthermore, a first passage 11 is provided in the second valve body 9 to communicate the first passage 2 and the second passage 3, and a first valve seat 12 is formed in this passage 11. A first valve body 13 that contacts and separates from the first valve seat 12 to open and close the first flow path 11,
It is disposed within the valve body 1 so as to be freely slidable in substantially the same direction as the second valve body 9. On the other hand, the valve body 1 is provided with an electric drive mechanism 17 for driving the first valve body 13, and furthermore, engagement means 28, 29 are provided between the first valve body 13 and the second valve body 9. After the first valve seat 12 is opened by the movement of the first valve body 13,
Further, when the first valve body 13 is moved in the valve opening direction, the second valve body 9 is moved in the valve opening direction via the engaging means 28 and 29.

(Function) In the normal operating state of the electric expansion valve described above, the first passage 1 connecting the first passage 2 and the second passage 3 is
1, the amount of refrigerant supplied to the second passage 3 is controlled by adjusting the opening degree between the first valve seat 12 and the first valve body 13. At this time, the second valve body 9
, a force from the high-pressure liquid refrigerant in the first passage 2 acts in the valve-closing direction in the pressure equalizing portion 9a, and a force in the valve-opening direction acts on the valve portion 9b. Since the first passage 2 serves as an inlet for high-pressure liquid refrigerant, and the third passage 4 serves as an inlet for high-pressure gas refrigerant or high-pressure liquid refrigerant, the pressures in both passages 2 and 4 are approximately equal, and Since the pressure equalizing valve seat 7 and the second valve seat 8 have approximately the same diameter, approximately the same forces act in opposite directions on the second valve body 9, and these forces cancel each other out. Become. As a result, the valve portion 9b is maintained in contact with the second valve seat 8 by the force of the biasing means 27, thereby preventing refrigerant from leaking from the third passage 4 to the second passage 3. It is possible.

In addition, during defrosting operation, the first valve body 13 is further moved in the valve opening direction, and the engagement means 28 and 29 provided between the first valve body 13 and the second valve body 9 engage with each other. By moving the second valve body 9 in the opening direction and separating the second valve body 9 from the second valve seat 8, the second valve body 9 is opened.
The flow path 6 is opened, thereby allowing the third passage 4 to communicate with the second passage 3. In this case, in the state before the second valve body 9 opens, the second valve body 9
Since the forces acting from the first passage 2 and the third passage 4 cancel each other out as described above, the force required to open the second valve body 9 during defrosting operation is equal to A force slightly larger than the force applied by means 27 is required, and the force required to open the second valve body 9 is small.

(Example) Next, a specific example of the electric expansion valve of this invention will be described in detail with reference to the drawings.

In FIG. 1, reference numeral 1 indicates a valve body, and this valve body 1 has a first passage 2 that opens on the circumferential side thereof, and a position below the first passage 2 that extends through the valve body 1. A second passage 3 that opens to the circumferential side and a third passage 4 that opens to the lower end surface of the valve body 1 are respectively bored. The first passage 2 and the second passage 3 communicate with each other via a pressure equalizing passage 5, and the third passage 4 and the second passage 3 communicate with each other through a second passage 6.
These pressure equalizing passages 5 and the second
The flow path 6 is formed substantially coaxially with the flow path 6 as shown in the figure. A pressure equalizing valve seat 7 is formed in the pressure equalizing passage 5, and a second valve seat 8 having approximately the same diameter as the pressure equalizing valve seat 7 is formed in the second flow passage 6. A second valve body 9 is disposed within the pressure equalizing passage 5 and the second flow passage 6 so as to be movable in the vertical direction. This second valve body 9
has a rod-like lower part and a cylindrical upper part, and has a pressure equalizing part 9a in the middle.
However, valve portions 9b are formed at their lower ends, so that the pressure equalizing portion 9a can contact the pressure equalizing valve seat 7, and the valve portion 9b can contact the second valve seat 8 at the same time. . In other words, the second valve body 9
This allows the pressure equalization path 5 and the second flow path 6 to be opened and closed simultaneously. In the figure, the second valve seat 8 is a cylindrical member 1 separate from the valve body 1.
0, but when assembling the valve, the second
The pressure equalizing portion 9a of the valve body 9 is brought into contact with the pressure equalizing valve seat 7, and in this state, the cylindrical member 10 is screwed onto the valve body 1 from below, and the second valve is attached to the second valve seat 8. The cylindrical member 10 is in contact with the valve portion 9b of the body 9.
This is to ensure that the pressure equalizing part 9a and the valve part 9b of the second valve body 9 are brought into accurate contact with both the valve seats 7 and 8 by adopting a work procedure that keeps the pressure constant.

The second valve body 9 is provided with a first passage 11 for communicating the first passage 2 and the second passage 3. A through hole 11a passing through the inside and outside of the upper cylindrical wall of the body 9
and a shaft hole 11b that communicates with the inside of the cylindrical portion and extends downward from the axial center of the rod-shaped portion;
b, and a through hole 11c that extends through the rod-shaped portion in the radial direction. In other words, the refrigerant in the first passage 2 flows into the cylindrical part through the through hole 11a, and then reaches the second passage 3 through the shaft hole 11b and the through hole 11c. . And in the first flow path 11,
A first valve seat 12 is formed at the upper peripheral edge of the shaft hole 11b, and a first valve body 13 is provided with respect to the first valve seat 12.
are designed so that they can come into contact with each other and separate from each other. That is, the first valve body 13 is arranged coaxially within the cylindrical portion of the second valve body 9, so that both valve bodies 9 and 13 can move in the same direction.

On the other hand, a cylindrical case 16 whose upper end is sealed with a cap 15 is attached to the upper part of the valve body 1, and inside and outside of this case 16, the first valve body 13 is placed vertically. An electric drive mechanism 17 is arranged for driving. This drive mechanism 17
has a structure in which a coil 18 is attached to the outer periphery of the case 16, a rotor 19 is arranged inside the case 16, and a permanent magnet 20 is fixed around the rotor 19. ,
By inputting an electrical input such as a pulse to the coil 18, the rotor 1 is
9 can be rotated. Further, a rotary screw bearing 21 is fixed to the inner circumference of the rotor 19, and this screw bearing 21 is attached to the valve body 1.
It is screwed onto a fixed screw bearing 22 fixed to. That is, when the rotor 19 rotates, it is guided by the screw bearings 21 and 22, and can move up and down as the rotor 19 rotates. Further, the upper end of the first valve body 13 is led out upward through the axial center of the rotor 19, and a fixing ring 23 is attached to this lead-out end. Further, a spring receiver 24 is attached to the middle part of the first valve body 13, and a spring 25 is interposed between the spring receiver 24 and the rotor 19. is biased toward the tip side by As a result of the above, when the rotor 19 descends, the first valve body 13 is driven downward via the spring 25 in the valve closing direction, while the rotor 1
When the rotor 9 rises, the upper surface of the rotor 19
The first valve body 13 engages with the fixing ring 23 of the valve body 13, and due to the engagement at this portion, the first valve body 13 resists the force of the spring 25.
is moved upward in the valve opening direction.

On the other hand, a cylindrical gasket 26 is attached to the upper end of the second valve body 9.
A spring 27 as a biasing means is also interposed between the valve and the rotor 19, and the second valve body 9 is pressed and biased downward in the valve closing direction by the spring 27. . In addition, the gasket 26 of the first valve body 13
An engagement ring 28 that protrudes radially outward is attached at a position further below. This engagement ring 28 is connected to the lower end surface 29 of the packing 26.
Together, they constitute an engaging means. That is, the lower end surface 29 of the gasket 26 is connected to the second valve body 9.
The electric drive mechanism 17 is formed to protrude radially inward from the inner peripheral surface of the electric drive mechanism 17.
When the first valve body 13 is raised, the engagement ring 28 is brought into contact with the lower end surface 29 of the packing 26, and by further raising the first valve body 13, the second valve body 13 is raised. The valve body 9 is configured to be able to rise against the force of the spring 27, that is, move in the valve opening direction.

By the way, a stopper mechanism is provided on the upper part of the rotor 19 for determining the upper and lower limit positions of the rotor 19, so this point will be briefly explained next. First, a screw shaft 30 is provided vertically from the cap 15, and a rotating member 31 is screwed onto the screw shaft 30. In this case, the screw shaft 30 has its lead connected to the rotating screw bearing 21.
A reed that is sufficiently larger than the reed is used. On the other hand, a pair of guide members 32, 32 are erected on the upper surface of the rotor 19, and the guide members 32, 32 are fitted into through holes 33, 33 provided at both ends of the rotary member 31. ing. In other words, the rotary member 31 is rotated by the rotation of the rotor 19 and can be driven in the vertical direction. Elastic stoppers 34 and 35 are attached to the upper and lower ends of the screw shaft 30, respectively, so that when the rotary member 31 moves up and down due to the rotation of the rotor 19, the upper or lower surface of the rotary member 31 is moved upwardly or downwardly. By contacting the side stoppers 34 and 35, further rotation of the rotating member 31, that is, further rotation of the rotor 19, can be restricted.

FIG. 2 shows an example of a refrigerant circuit using the electric expansion valve A. In the figure, 36 indicates an indoor heat exchanger, and 37 indicates an outdoor heat exchanger, and both heat exchangers 36, 37 is the liquid pipe 38 and the gas pipe 3
9 are connected in parallel. The liquid pipe 38
, the electric expansion valve A is connected to the gas pipe 39.
A four-way switching valve 40 is provided in each of the four-way switching valves 40 .
In this case, the electric expansion valve A is arranged such that its first passage 2 is connected to the indoor heat exchanger 36 side, and its second passage 3 is connected to the outdoor heat exchanger 37. Further, a discharge pipe 42 and a suction pipe 43 of a compressor 41 are connected to the four-way switching valve 40, respectively. A bypass pipe 44 is connected to a portion 39a of the gas pipe 39 that serves as a passage for a low-pressure gas refrigerant during refrigerant operation and serves as a passage for high-pressure discharged gas refrigerant during heating operation, and this bypass pipe 44 serves as a passage for the electric expansion valve A. It is connected to the third passage 4 of.

Next, the operating state of the electric expansion valve A in the refrigerant circuit described above will be explained. First, during heating operation, the discharged gas refrigerant from the discharge pipe 42 of the compressor 41 is transferred to the four-way selector valve 4, as shown by the broken line in FIG.
0 and the indoor heat exchanger 36 via the gas pipe 39a.
The high-pressure liquid refrigerant that is sent to and condenses and then exits the indoor heat exchanger 36 flows into the electric expansion valve A from the first passage 2. This high-pressure liquid refrigerant is
In the flow path 11, the fluid flows to the second path 3 through the first flow path 11, and in the flow path 11, the opening degree between the first valve seat 12 and the first valve body 13 is adjusted. By this, the outdoor heat exchanger 37 is removed from the second passage 3.
Controls the amount of refrigerant supplied to the The gas refrigerant evaporated in the outdoor heat exchanger 37 then passes through the four-way switching valve 40 and the suction pipe 43 to the compressor 41.
It is flowed back to. In this case, since high pressure gas refrigerant is introduced into the third passage 4 of the electric expansion valve A from the bypass pipe 44, the second valve body 9 is pressed in the valve opening direction at the second valve seat 8. However, since high-pressure liquid refrigerant is introduced into the first passage 2, the second valve body 9 is also moved in the closing direction by this liquid refrigerant at the pressure equalizing valve seat 7. You will be under pressure. Since the diameter of the second valve seat 8 and the diameter of the pressure equalizing valve seat 7 are made substantially the same, the above-mentioned pressing forces are substantially equal and cancel each other out. As a result, the second valve body 9 , the force of the spring 27 presses and contacts the pressure equalizing valve seat 7 and the second valve seat 8, and this state is maintained.

On the other hand, when the amount of frost on the outdoor heat exchanger 37 increases and a defrosting operation is performed, the first valve body 13 is further pulled up in the valve opening direction from the flow rate control position as described above. Then, the engagement ring 28 provided on the first valve body 13 comes into contact with the lower end surface 29 of the gasket 26 attached to the second valve body 9, and the engagement of both 28 and 29 causes the second valve body 9 to close. The second valve body 9 is pulled up.
is separated from the second valve seat 8, the second passage 6 is opened, and the third passage 4 communicates with the second passage 3. As a result, the discharged gas refrigerant from the compressor 41 is supplied to the outdoor heat exchanger 37 via the bypass pipe 44, the third passage 4, and the second passage 3, respectively, and the heat exchanger 37 is defrosted. It will be done. At this time, due to the movement of the second valve body 9, the second flow path 6 and the pressure equalization path 5 are simultaneously opened, so that the state of communication between the first path 2 and the second path 3 is maintained, and the indoor heat exchange The refrigerant is supplied to the indoor heat exchanger 36, albeit in a small amount.
heating operation status will be maintained. Then, the force acting on the second valve body 9 before opening the valve, that is, the force acting on the second valve body 9 from the high pressure liquid refrigerant in the first passage 2, and the force acting on the second valve body 9 from the high pressure gas refrigerant in the third passage 4. Since the two forces acting on the body 9 cancel each other out as described above, the force required to open the second valve body 9 may be small enough to overcome the force of the spring 27. Therefore, it becomes possible to configure the electric drive mechanism for driving the second valve body 9 more compactly than in the past.

On the other hand, when performing cooling operation in the refrigerant circuit, the four-way switching valve 40 is switched, and at this time, the refrigerant is transferred from the discharge pipe 42 of the compressor 41 to the four-way switching valve 40, as shown by the solid line in FIG. The high-pressure liquid refrigerant is sent to the outdoor heat exchanger 37 to be condensed, and then the high-pressure liquid refrigerant coming out of the outdoor heat exchanger 37 flows into the electric expansion valve A from the second passage 3. This liquid refrigerant flows into the first passage 2 through the first passage 11 in the electric expansion valve A.
3, the flow rate of the refrigerant is controlled. The low-pressure liquid refrigerant from the first passage 2 is evaporated in the indoor heat exchanger 36, and then returned to the compressor 41 via the gas pipe 39a, the four-way switching valve 40, and the suction pipe 43. . In this case, the force from the low pressure gas refrigerant on the third passage 4 side is applied to the second valve body 9 in the valve opening direction, and at the same time, the force from the low pressure liquid refrigerant on the first passage 2 side is applied to the valve closing direction. However, since these forces cancel each other out as described above, the state in which the second valve element 9 contacts the second valve seat 8 and closes the second flow path 6 is as follows. It will be maintained.

FIG. 3 shows a modified example of a refrigerant circuit using the electric expansion valve A described above. This refrigerant circuit is different from the above circuit in that a bypass pipe 45 is provided between the indoor heat exchanger 36 and the electric expansion valve A, and this bypass pipe 45 is connected to the third passage 4 of the electric expansion valve A. connection, and during defrosting operation, high-pressure liquid refrigerant is supplied from both the first passage 2 and the third passage 4 to the outdoor heat exchanger 37, and the evaporation temperature of the outdoor heat exchanger 37 is raised to perform defrosting. This is what I decided to do. The other configurations are the same as the refrigerant circuit described above, and the electric expansion valve A operates in substantially the same manner as described above. Therefore, the same parts are denoted by the same reference numerals and the explanation thereof will be omitted.

FIG. 4 shows another modification of the refrigerant circuit using the electric expansion valve A described above. This is a refrigerant circuit for a refrigeration system, and under normal refrigeration operating conditions,
The flow rate of refrigerant supplied from the condenser 46 to the evaporator 47 is controlled by the first valve body 13 between the second passage 3 and the first passage 2 of the electric expansion valve A. In this case, the third
The passage 4 is connected to a drain pan heater 48, and no refrigerant is allowed to flow through the drain pan heater 48 during normal refrigeration operation. On the other hand, when performing defrosting operation, the four-way switching valve 40 is switched, and the first valve body 13 and the second valve body 9 are moved so that both the first passage 2 and the third passage 4 are connected to the second passage. The high-pressure gas refrigerant from the compressor 41 is communicated with the passage 3 to the evaporator 4.
7 and the drain pan heater 48. Since the other circuit configurations in the Naoho circuit are the same as the circuit shown in FIG. 2, the same parts are designated by the same reference numerals and the explanation thereof will be omitted.

In the above embodiment, a motor is used as the electric drive mechanism 17, but it may be an electromagnetic type.

(Effect of the invention) In the electric expansion valve of this invention, the third passage, which serves as the inlet of the high-pressure gas refrigerant or high-pressure liquid refrigerant, is communicated with the second passage, which serves as the outlet of the refrigerant, during the heating action of the heat exchanger on the user side. A second valve body is provided to prevent the high pressure from acting on the second valve body at both valve seats. Since the forces from the refrigerant cancel each other out, the force required to open the second valve element is reduced, and therefore the electrical drive function can be downsized. Furthermore, since the structure is such that the second valve body is brought into contact with the second valve seat by the force of the biasing means, thereby closing the third passage, when the third passage is closed, the refrigerant from the passage is removed. Leakage can be prevented, and therefore, it is possible to prevent the conventional deterioration in operating performance due to refrigerant leakage.

[Brief explanation of the drawing]

Fig. 1 is a central vertical cross-sectional view showing one embodiment of the electric expansion valve of this invention, Fig. 2 is a circuit diagram showing an example of a refrigerant circuit using the above-mentioned electric expansion valve, and Fig. 3 is an example of a modification of the refrigerant circuit. FIG. 4 is a circuit diagram showing another modification of the refrigerant circuit, and FIG. 5 is an explanatory diagram of a conventional example. 1...Valve body, 2...First passage, 3...Second passage, 4...Third passage, 5...Pressure equalization passage, 6...Second passage
Flow path, 7... pressure equalization valve seat, 8... second valve seat, 9...
Second valve body, 11...first flow path, 12...first valve seat, 13...first valve body, 17...electric drive mechanism, 27...spring.

Claims (1)

[Scope of utility model registration request] During the heating action of the heat exchanger on the user side, the first passage 2 serves as an inlet for the high-pressure liquid refrigerant, and the second passage serves as an outlet for the refrigerant.
A passage 3 and a third passage 4 serving as an inlet for high-pressure liquid refrigerant or high-pressure gas refrigerant are respectively bored in the valve body, and the first passage 2 and second passage 3 are communicated via a pressure equalization passage 5. In addition, the third passage 4 and the second passage 3
A second valve seat 8 having approximately the same diameter as the opening on the first passage 2 side of the pressure equalizing passage 5 is provided in the second passage 6. On the other hand, a second valve body 9 is slidably disposed within the valve body 1, and the second valve body 9 contacts and separates from the second valve seat 8 to open the second flow path 6. A valve portion 9b that opens and closes, and a pressure equalizing portion 9a that closes the pressure equalizing path 5 when the valve portion 9b is in contact with the second valve seat 8 are provided, and the second valve body 9 is A biasing means 27 biases the valve in the valve closing direction, and a first passage 11 is provided in the second valve body 9 for communicating the first passage 2 and the second passage 3. A first valve seat 12 is formed in the valve body 1, and a first valve body 13 that contacts and separates from the first valve seat 12 to open and close the first flow path 11 is disposed inside the valve body 1. The first valve body 1 is disposed slidably in substantially the same direction as the valve body 9, and the first valve body 1
An electric drive mechanism 17 for driving 3 is provided,
Further, engagement means 28 and 29 are provided between the first valve body 13 and the second valve body 9, and after the first valve seat 12 is opened by the movement of the first valve body 13, the engagement means 28 and 29 are further provided in the valve opening direction. An electric expansion valve characterized in that when the first valve body 13 is moved, the second valve body 9 is moved in the valve opening direction via the engaging means 28 and 29.