JPH0311666Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) This invention relates to an electric expansion valve used in a heat pump circuit, and in particular an electric expansion valve that can open and close the flow path within the valve body when the expansion function is not in use. Related to valves.

(Prior Art) An air conditioner in which multiple indoor units are connected to one outdoor unit to perform both cooling and heating functions is described in, for example, Utility Model Application No. 59-25067. It is well known that there are many. A refrigerant circuit in this type of air conditioner is schematically shown in FIG. 3, where 1 indicates an outdoor unit and 2 indicates an indoor unit. Note that since each of the indoor units 2...2 has the same structure, only one indoor unit 2 is shown in the figure for convenience. As shown in the diagram, this circuit consists of compressor 3
A four-way switching valve 4 controls the flow direction of the refrigerant sent from the refrigerant, and during cooling, the refrigerant is returned to the compressor 3 from the outdoor heat exchanger 5 via the cooling expansion valve 6 and the indoor exchanger 7 (in the figure). On the other hand, during heating, the flow is reversed to the above, and the flow is transferred from the indoor heat exchanger 7 to the compressor 3 via the heating expansion valve 8 and the outdoor heat exchanger 5 (the flow shown by the solid line in the figure). This method adopts the flow shown in . In addition to the expansion valve 6, the indoor unit 2 has three check valves 9 and 1 to switch between air conditioning and heating and selectively stop using the unit 2 as described above.
0,11 and one electromagnetic on-off valve 12 are used. That is, during cooling operation, refrigerant is supplied from the liquid pipe 1 to the expansion valve 6 via the check 9 and the electromagnetic on-off valve 12, and the depressurized refrigerant is supplied to the liquid pipe 1.
4 to the indoor heat exchanger 7, while during heating operation, the refrigerant is sent from the liquid pipe 13 to the heating expansion valve 8 via the check valve 10, electromagnetic shut-off valve 12, and check valve 11 from the liquid pipe 14. It is sent out.

(Problems to be solved by the invention) By the way, in the above-mentioned device, three check valves 9, 10, 11 and one electromagnetic shut-off valve 12 are used, and it is not necessary to connect these as described above. For this reason, the piping configuration becomes complicated, which also has the disadvantage of increasing costs.
Another drawback is that the reliability of the entire device is likely to deteriorate because of the large number of parts used.

Therefore, the expansion valve has the following two functions: when the function as an expansion valve is required, it operates as a normal expansion valve, and on the other hand, when the function as an expansion valve is not required, the internal flow path is fully opened or fully closed. The check valves 9 and 1 are provided with a function as an on-off valve.
It is conceivable to use the 0, 11 and electromagnetic on-off valves 12 and to omit the associated piping.

Therefore, as a countermeasure, the stroke of the expansion valve is increased, throttle control is performed when the valve body is in a position close to the valve seat, and the fluid is closed while the valve body is in contact with the valve seat. On the other hand, it is possible to adopt a structure that fully opens the flow path when the valve body is moved far away from the valve seat, but in that case, the entire valve would be large and expensive. This may cause a problem. It is also possible to increase the diameter of the valve seat to provide opening and closing functions, but in this case, the opening area of the valve will change significantly due to slight fluctuations in the stroke of the valve body. Another disadvantage is that precise throttle control cannot be performed when used as an expansion valve.

This invention was made to solve the above-mentioned drawbacks of the conventional system, and its purpose was to simplify the piping configuration by eliminating the need for the three check valves and electromagnetic shut-off valves that were conventionally used. Therefore, it is an object of the present invention to provide an electrically driven expansion opening/closing valve that can be constructed at low cost, has a compact expansion valve itself, and can be precisely controlled in the same manner as conventional ones.

(Means for solving the problem) Therefore, in the electrically driven expansion on-off valve of this invention, as shown in FIG. A first passage 18 that serves as an outlet for refrigerant, a second passage 19 that serves as an outlet for low-pressure liquid refrigerant during cooling operation and an inlet for high-pressure liquid refrigerant during heating operation, and valve body 1.
7, and both passages 18 and 19 are communicated via a first flow passage 20 bored in the valve body 17,
A first valve seat 23 is provided in the first flow path 20, and in the valve body 17, abutting against the first valve seat 23,
Valve body 2 for opening and closing the first flow path 20 by separating
1 are slidably arranged. On the other hand, the valve body 17 further includes the first passage 18 and the second passage 25.
A third passage 24 is provided which communicates with the high-pressure liquid refrigerant through the passageway, and the second passage 25 is provided with a second valve seat 27 having a larger diameter than the first valve seat 23. The valve seat 27 is arranged so that it can be opened and closed at the same time as the first passage 20 is opened and closed by a stepped part 40 provided on the valve body 21, and the third passage 24 is configured to prevent fluid from flowing into the valve body 17. Allowable check valve 28
An electric drive mechanism 31 for driving the valve body 21 is attached to the valve body 17.

(Function) First, during cooling operation, the electric drive mechanism 31 drives the valve body 21 to open the first valve seat 23 and adjust the degree of opening to open the first valve seat 23.
Liquid refrigerant reduced to a predetermined pressure is supplied from the passage 18 to the second passage 19. In this case, the second valve seat 27 is also opened, but the third passage 2
Since the check valve 28 is connected to the third passage 24, the liquid refrigerant will not flow out from the third passage 24. On the other hand, during heating operation, the drive mechanism 31 fully opens the valve body 21. Then, the second valve seat 2
7 is in an open state, and the third passage 24 is connected to the first passage 1.
It will be connected to 8. At this time, the second valve seat 27
Since the bore diameter of the valve body 17 is made sufficiently large, most of the high pressure liquid refrigerant supplied to the valve body 17 is
4 into the first passage 18. As a result of the high-pressure liquid refrigerant flowing from the third passage 24, which has a large flow area, to the first passage 18, almost no pressure difference occurs before and after the expansion valve. Also, when driving as above,
When stopping the passage of the liquid refrigerant, the valve body 21 may be driven by the drive mechanism 31 to fully close both the first valve seat 23 and the second valve seat 27.

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

The air conditioner shown in FIGS. 1 and 2 has a structure in which a plurality of indoor units 2...2 are connected to one outdoor unit 1. In addition, since the structure of each indoor unit 2...2 is the same, the figures are shown for convenience.
Only one indoor unit 2 is shown. The outdoor unit 1 is similar to the conventional unit described above,
It has a compressor 3, a four-way switching valve 4, an outdoor heat exchanger 5, a heating expansion valve 8, and a check valve 15. The indoor unit 2 also includes an indoor heat exchanger 7 and an electrically driven expansion on/off valve 16, which is a feature of this invention.

The expansion on-off valve 16 has a valve body 17, and the valve body 17 includes a first passage 18 that serves as an inlet for high-pressure liquid refrigerant during cooling operation and an outlet for high-pressure liquid refrigerant during heating operation; A second passage 19 is provided which serves as an outlet for low-pressure liquid refrigerant at times and an inlet for high-pressure liquid refrigerant during heating operation. Both passages 18 and 19 are connected to the first passage 1 as shown in the figure.
8, the valve body 17 extends inward to the axial center of the valve body 17, and then extends downward along the axial center of the valve body 17. Further, at the axial center of the valve body 17,
A valve body 21 is slidably arranged, and a valve 22 formed at the tip thereof is brought into contact with and separated from a first valve seat 23 provided in the first flow path 20.
The first flow path 20 can be opened and closed. Note that the drive mechanism for this valve body 21 will be described later. At a position above the first passage 18 in the figure, a third passage 24 is formed in the valve body 17, which opens on the side thereof and serves as an inlet for high-pressure liquid refrigerant during heating operation. This third passage 24 is connected to the first passage through the second flow passage 25.
It communicates with passage 18. This second flow path 25
As shown in the figure, is a flow path that extends from the third passage 24 to the axial center of the valve body 17, then extends downward through the axial center of the valve body 17, and reaches the first passage 18. . On the other hand, the midway portion 26 of the valve body 21 is formed to have a slightly larger diameter than the distal end thereof, and a stepped portion 40 is formed at a lower position of the large diameter portion 26. A second valve seat 27 is formed at a position opposite to the stepped portion 40 .
In other words, as the valve body 21 moves, the stepped portion 40 allows the second valve seat 27 to be opened and closed at the same time as the first valve seat 23 is opened and closed. Note that the diameter of the second valve seat 27 is formed to be sufficiently larger than the diameter of the first valve seat 23, as shown in the figure. Further, a check valve 28 is connected to the third passage 24, and although this check valve 28 allows refrigerant to flow into the valve body 17, it prevents the refrigerant from flowing out from the valve body 17. It has a function, and in addition to being placed outside the valve body 17 as shown in the figure, it can also be placed inside the valve body 17. A cylindrical case 29 is fixed to the upper part of the valve body 17, and the upper end of the case 29 is sealed with a cap 30.

Since the valve body 21 is driven up and down by an electric drive mechanism 31, the drive mechanism 31 will be explained below.
This drive mechanism 31 has a coil 32 attached to the outer periphery of the case 29 and a rotor 33 arranged inside the case 29, and a permanent magnet 34 is fixed to the outer periphery of the rotor 33. The rotor 33 can be rotationally driven via the magnet 34 by electrical input such as a pulse to the coil 32. A rotary screw bearing 35 is fixed to the inner peripheral portion of the rotor 33, and this bearing 35 is screwed to a fixed screw bearing 36 fixed to the valve body 17. In other words, the rotor 3
When the rotor 33 rotates, the rotor 33
5 and 36, and can move up and down as they rotate. On the other hand, the valve body 2
The base end of the rotor 33 passes through the axial center of the rotor 33 and is led out to the upper part thereof, and a fixing ring 37 is attached near the end. Further, a spring 38 is interposed between the rotor 33 and the valve body 21, and the valve body 21 is urged by the spring 38 toward the first valve seat 23 on the tip side. . As a result, when the rotor 33 descends, the valve body 21 is driven downward via the spring 38, while when the rotor 33 ascends, the upper surface of the rotor 33 Fixed ring 3
7, and engagement at this portion causes the valve body 21 to rise. A protrusion 39 is formed on the lower surface of the cap 30, and this protrusion 39 is for determining the upper limit of the lift of the valve body 21.

Next, the operating state of the expansion on-off valve 16 will be explained. First, the operating state during cooling operation will be explained. At this time, this expansion on-off valve 16 is
As shown in the figure, it will function as an expansion valve.
That is, the electric drive mechanism 31 drives the valve body 21 to move the valve 22 away from the first valve seat 23, and by adjusting the opening degree during that time, the valve body 21 is moved from the first passage 18 to the second valve seat 23. Liquid refrigerant reduced to a predetermined pressure is supplied to the passage 19. In this case, the second valve seat 27 will also be opened, but since the check valve 28 is connected to the third passage 24, liquid refrigerant will not flow out from the third passage 24. On the other hand, during heating operation, the drive mechanism 31 fully opens the valve body 21. Then, both the first valve seat 23 and the second valve seat 27 become open, and both the second passage 19 and the third passage 24 communicate with the first passage 18. At this time, since the diameter of the second valve seat 27 is sufficiently larger than the diameter of the first valve seat 23, most of the high-pressure liquid refrigerant supplied from the liquid pipe 14 passes through the third passage 24 to the first passage. It will be introduced in 18th.
As a result of the high-pressure liquid refrigerant flowing from the third passage 24, which has a large flow area, to the first passage 18, almost no pressure difference is generated before and after the expansion valve 16.
The high-pressure liquid refrigerant passes freely through the interior and is then supplied from the liquid pipe 13 to the heating expansion valve 8. Furthermore, during the cooling operation or the heating operation as described above, the operation of a specific indoor unit 2 is stopped by driving the valve body 21 by the drive mechanism 31, and controlling the first valve seat 23 and the second valve seat 21. This can be done by completely closing both of 27 and stopping the passage of refrigerant.

As mentioned above, the expansion on-off valve has the same function as a conventional expansion valve during cooling operation when it is used as an expansion valve, but on the other hand, during heating operation when it is not used as an expansion valve, it becomes fully open and high-pressure liquid Conventionally, the refrigerant is allowed to freely pass through, and when it is necessary to stop the operation of a specific indoor unit 2 during heating/cooling, the valve can be closed and the passage of the refrigerant can be stopped. For each indoor unit 2, three check valves 9, 10, 11 and one electromagnetic shut-off valve 12 are used to switch between cooling and heating and to stop the unit 2, and a complicated Instead of using piping, it is now sufficient to use only one expansion valve 16 as described above. Therefore, the piping work can be greatly simplified, the cost can be significantly reduced, and the reliability of the device can be improved by reducing the number of parts.

Note that in the above embodiment, the electric drive mechanism 3
Although an example using a motor is shown as No. 1, an electromagnetic type may be used.

(Effect of the invention) As mentioned above, the electrically driven expansion on/off valve of this invention performs the same function as a conventional expansion valve during cooling operation when it is used as an expansion valve, while it performs the same function as a conventional expansion valve during cooling operation when it is used as an expansion valve. During operation, it is fully open to allow the free passage of refrigerant, and when the use of a particular unit is to be stopped, it is fully closed to stop the passage of refrigerant. The number of parts is reduced compared to the conventional model,
In addition, the piping configuration can be simplified, and
It becomes possible to reduce the cost of the entire device. Moreover, the expansion on-off valve itself can be constructed compactly, and precise control can be performed as in the conventional case.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional view of one embodiment of the electrically driven expansion on-off valve of this invention in a cooling operation state, Fig. 2 is a longitudinal sectional view of its heating operation state, and Fig. 3 is a circuit diagram showing a conventional example. be. 16... Expansion on/off valve, 17... Valve body, 18...
...first passage, 19...first passage, 20...first passage, 21...first valve body, 23...first valve seat, 24
...Third passage, 25...Second flow path, 27...Second
Valve seat, 28... Check valve, 31... Electric drive mechanism, 40... Stepped portion.

Claims (1)

[Scope of utility model registration request] The first passage 18 serves as an inlet for high-pressure liquid refrigerant during cooling operation and serves as an outlet for high-pressure liquid refrigerant during heating operation.
and a second passage 19 that serves as an outlet for low-pressure liquid refrigerant during cooling operation and an inlet for high-pressure liquid refrigerant during heating operation.
are provided in the valve body 17, and both passages 18 and 19 are communicated via a first passage 20 bored in the valve body 17, and a first valve seat 23 is provided in the first passage 20.
A valve element 21 for opening and closing the first flow path 20 by contacting and separating from the first valve seat 23 is slidably disposed within the valve body 17, while the valve body 17 17 further includes the first passage 18 and the second passage.
A third passage 24 is provided which communicates through a passage 25 and serves as an inlet for the high-pressure liquid refrigerant, and the second passage 25 is provided with a second valve seat 27 having a larger diameter than the first valve seat 23. This second valve seat 27 is connected to the valve body 21.
A check valve 28 is connected to the third passage 24 to allow fluid to flow into the valve body 17. , an electrically driven expansion opening/closing valve characterized in that an electrical drive mechanism 31 for driving the valve body 21 is mounted on the valve body 17;