JP3481036B2 - Expansion valve - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an expansion valve for adiabatically expanding a refrigerant while controlling the flow rate of the refrigerant sent to an evaporator in a refrigeration cycle. 2. Description of the Related Art FIG. 5 shows an example of an expansion valve 10 which has been widely used in the past, and 1 is an evaporator. [0003] An inlet end of a low-pressure refrigerant passage 12 formed in a main body block 11 of the expansion valve 10 is connected to an outlet of the evaporator 1, and an outlet end of the high-pressure refrigerant passage 13 is connected to an inlet of the evaporator 1. It is connected to the. The low-pressure refrigerant flow path 12 and the high-pressure refrigerant flow path 13 are formed in parallel with each other.
Penetrates between the low-pressure refrigerant channel 12 and the high-pressure refrigerant channel 13. Further, a temperature sensing chamber 30 is attached to an opening formed so as to pass outward from the low-pressure refrigerant flow path 12. [0005] The high-pressure refrigerant flow path 13 has an intermediate portion formed as a throttle hole 15 having a circular cross-sectional shape and a narrowed cross-sectional area, and is formed coaxially with the through hole 14. The mouth of the upstream opening is beveled in a tapered shape to form a valve seat 20. A spherical valve element 21 having a diameter larger than the diameter of the throttle hole 15 is disposed facing the valve seat 20 from the upstream side. As a result, the narrowest part of the gap between the valve element 21 and the valve seat 20 becomes the throttle portion of the high-pressure refrigerant flow path 13,
The high-pressure refrigerant adiabatically expands in the downstream pipeline from there to the evaporator 1. The valve body 21 is urged by the compression coil spring 17 in a direction approaching the valve seat 20 (ie, in a closing direction). However, between the valve body 21 and the compression coil spring 17, the valve body 21 is received on one side and the compression coil spring 17 is provided on the other side so as to transmit the urging force of the compression coil spring 17 to the valve body 21. Receiving valve body 16 is interposed. Reference numeral 18 denotes an adjusting nut which is screwed and attached to the main body block 11 to adjust the urging force of the compression coil spring 17, and 19 denotes an O-ring for sealing between the high-pressure refrigerant flow path 13 and the outside. It is. The rod 23 inserted into the through hole 14
The upper end reaches the temperature sensing chamber 30, the middle part passes through the through-hole 14 vertically across the low-pressure refrigerant passage 12, and the lower end is welded to the head of the valve 21. Have been. The rod 23 is formed thinner than the inner diameter of the throttle hole 15 so that the refrigerant can pass between the inner wall surface of the throttle hole 15 and the rod. Therefore, the valve body 21 is pushed by the rod 23 against the urging force of the compression coil spring 17, and the valve seat 2 is pushed.
As the distance from zero increases, the flow path area of the high-pressure refrigerant flow path 13 increases. As described above, the flow path area of the high-pressure refrigerant flow path 13 changes in accordance with the amount of movement of the rod 23, thereby changing the amount of the high-pressure refrigerant supplied to the evaporator 1. Reference numeral 24 denotes an O-ring for sealing between the high-pressure refrigerant flow path 13 and the low-pressure refrigerant flow path 12. The O-ring 24 is disposed adjacent to the through hole 14 and in close contact with the outer peripheral surface of the rod 23. I have. Reference numeral 25 denotes a compression coil spring for pressing the O-ring 24 so as not to come off. The temperature sensing chamber 30 has a housing 31 made of a thick metal plate and a diaphragm 3 made of a flexible thin metal plate.
2 and a diaphragm receiving plate 33 disposed facing the center of the lower surface of the diaphragm 32.
One end of the rod 23 is in contact with the center of the lower surface of the. In the temperature sensing chamber 30, the refrigerant passages 12,
A gas in a saturated vapor state, which has the same or similar properties as the refrigerant flowing in the 13, is sealed therein, and the injection hole for gas filling is closed by a stopper 34. 36 is an O-ring for sealing. A bush 38 made of a plastic material or the like having a low thermal conductivity is fixed to an immovable portion between the low-pressure refrigerant flow path 12 and the temperature-sensitive chamber 30, and the low-pressure refrigerant wraps around the temperature-sensitive chamber 30. Regulated. However, in the bush 38, a ventilation groove 40 for penetrating the low pressure refrigerant flow path 12 and the temperature sensing chamber 30 side is penetrated. In the expansion valve configured as described above,
When the temperature of the low-pressure refrigerant flowing in the low-pressure refrigerant passage 12 decreases, the temperature of the diaphragm 32 decreases, and the saturated vapor gas in the temperature-sensitive chamber 30 condenses on the inner surface of the diaphragm 32. Then, the pressure in the temperature sensing chamber 30 decreases, and the diaphragm 32 is displaced inside the temperature sensing chamber 30, and accordingly, the diaphragm receiving board 33 is displaced in the axial direction of the rod 23 in the direction of escaping from the rod 23. 23 moves by being pushed by the compression coil spring 17. As a result, the valve element 21 moves toward the valve seat 20 and the flow area of the high-pressure refrigerant is reduced, so that the flow rate of the refrigerant sent into the evaporator 1 is reduced. When the temperature of the low-pressure refrigerant flowing in the low-pressure refrigerant flow path 12 rises, the valve element 21 is pushed by the rod 23 and moves away from the valve seat 20 by the operation reverse to the above, and the flow path area of the high-pressure refrigerant increases. Accordingly, the flow rate of the high-pressure refrigerant sent to the evaporator 1 increases. In this manner, the temperature-sensitive chamber 30 and the rod 2 correspond to the temperature of the low-pressure refrigerant sent from the evaporator 1.
The amount of the high-pressure refrigerant sent to the evaporator 1 is controlled by opening and closing the valve body 20 through the operation of the third operation. The high-pressure refrigerant sent to the expansion valve 10 may have a pressure fluctuation on the upstream side for some reason. Is transmitted to the expansion valve 10.
When the refrigerant pressure on the upstream side of the valve element 21 rises due to pressure fluctuation, it acts in a direction to close the valve element 21. FIGS. 6 to 8 show the movement of the valve element 21 at that time. First, as shown in FIG. 6, the valve element 21 starts to move in the direction approaching the valve seat 20. As shown in FIG. 7, the valve element 21 partially contacts the valve seat 20. Then, the valve element 21 easily slides in the rotational direction between the valve element receiver 16 and the valve element receiver 16 as shown by the arrow A, and is easily displaced laterally. As a result, the valve element 21 is easily displaced in the direction of the center of the valve seat 20, so that there is almost no resistance, and
As shown in (2), the valve element 21 is in a fully closed state where the valve seat 20 is completely closed. When the valve is completely closed immediately in this way, the refrigerant pressure on the upstream side of the valve body 21 further rises, and the pressure fluctuation becomes even greater. The operation of the valve 10 may become unstable. Such a phenomenon is caused by the valve body 21 as described above.
Is generated even if it is fixed to the rod 23. However, if the valve element 21 and the rod 23 cannot be fixed due to structural reasons, the valve element 21 can move freely, and the state is more likely to occur. According to the present invention, in an expansion valve having such a structure in which the valve element is not fixed to the rod, even if the pressure of the high-pressure refrigerant on the upstream side fluctuates and rises, the valve element suddenly moves. It is an object of the present invention to be able to maintain a stable operation without closing, without generating vibration or the like. In order to achieve the above object, an expansion valve according to the present invention is formed by narrowing a cross-sectional area in the middle of a high-pressure refrigerant passage through which a high-pressure refrigerant sent to an evaporator passes. And a spherical valve element disposed from the upstream side to a valve seat formed at the mouth of the upstream opening of the throttle hole, and the valve element is disposed on the valve seat from the upstream side. Urging means for urging toward the valve, and a temperature-sensing part which operates in response to the temperature of the low-pressure refrigerant sent from the evaporator, and the valve body, and is loosely inserted into the throttle hole. And a rod which is provided so that one end abuts on the valve body without being fixed thereto, so that the valve body is opened and closed with respect to the valve seat by the movement of the temperature sensing portion via the rod. In the valve, at the end face of the rod abutting on the valve body,
A recess is formed to guide the valve body pressed against the urging means to a position shifted from the center of the valve seat. Embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows an expansion valve 10 according to a first embodiment of the present invention, which is used, for example, in a refrigeration cycle of a vehicle indoor cooling device (car air conditioner). 1 is an evaporator. An inlet end of a low-pressure refrigerant passage 12 formed in a main body block 11 of the expansion valve 10 is connected to an outlet of the evaporator 1, and an outlet end of a high-pressure refrigerant passage 13 is connected to an inlet of the evaporator 1. It is connected to the. The low-pressure refrigerant flow path 12 and the high-pressure refrigerant flow path 13 are formed in parallel with each other.
Penetrates between the low-pressure refrigerant channel 12 and the high-pressure refrigerant channel 13. Further, a temperature sensing chamber 30 is attached to an opening formed so as to pass outward from the low-pressure refrigerant flow path 12. The high-pressure refrigerant flow path 13 has an intermediate portion formed as a throttle hole 15 having a circular cross-sectional shape and a narrower cross-sectional area, and is formed coaxially with the through hole 14. The mouth of the upstream opening is chamfered into a tapered shape having an angle of about 45 degrees to form the valve seat 20. A spherical valve element 21 having a diameter larger than the diameter of the throttle hole 15 is disposed facing the valve seat 20 from the upstream side. As a result, the narrowest part of the gap between the valve body 21 and the valve seat 20 becomes the throttle portion of the high-pressure refrigerant flow path 13,
The high-pressure refrigerant adiabatically expands in the downstream pipeline from there to the evaporator 1. The valve element 21 is urged by the compression coil spring 17 in a direction approaching the valve seat 20 (ie, in a closing direction). However, between the valve body 21 and the compression coil spring 17, the valve body 21 is received on one side and the compression coil spring 17 is provided on the other side so as to transmit the urging force of the compression coil spring 17 to the valve body 21. Receiving valve body 16 is interposed. Numeral 18 denotes an adjusting nut which is screwed and attached to the main body block 11 to adjust the urging force of the compression coil spring 17, and numeral 19 denotes an O-ring for sealing between the high-pressure refrigerant flow path 13 and the outside. It is. The rod 23 inserted in the through hole 14 without play is provided so as to be able to advance and retreat in the axial direction, and the lower end is in contact with the head of the valve 21 without being fixed thereto. I have. The rod 23 is formed thinner than the inner diameter of the throttle hole 15 so as to allow the refrigerant to pass between the inner wall surface of the throttle hole 15 and is arranged substantially coaxially with the throttle hole 15. Therefore, the valve body 21 is pushed by the rod 23 against the urging force of the compression coil spring 17 and the valve seat 2 is pushed.
As the distance from zero increases, the flow path area of the high-pressure refrigerant flow path 13 increases. As described above, the flow path area of the high-pressure refrigerant flow path 13 changes in accordance with the amount of movement of the rod 23, thereby changing the amount of the high-pressure refrigerant supplied to the evaporator 1. On the contact surface of the rod 23 with the valve body 21, a conical recess 22 as shown in an enlarged view in FIG.
The rod 23 is formed eccentrically with respect to the center axis position. The valve body 21 urged by the compression coil spring 17 is pressed against the recess 22, which will be described later. The temperature sensing chamber 30 has a housing 31 made of a thick metal plate and a diaphragm 3 made of a flexible thin metal plate.
2, a metal diaphragm receiving board 33 is disposed facing the center of the lower surface of the diaphragm 32. In the temperature sensing chamber 30, the refrigerant passages 12,
A gas in a saturated vapor state, which has the same or similar properties as the refrigerant flowing in the 13, is sealed therein, and the injection hole for gas filling is closed by a stopper 34. 36 is an O-ring for sealing. The stem 37 extending straight downward from the center of the lower surface of the diaphragm receiving board 33 is provided with the low-pressure refrigerant flow path 12.
The other end face is in contact with the end face of the rod 23 through the inside. Reference numeral 38 denotes a heat insulating cylinder attached so as to cover the outer peripheral surface of the stem 37, and 39 denotes a diaphragm 32
A pressure equalizing hole 24 for making the pressure of the back surface of the low pressure refrigerant flow channel 12 the same as that of the low pressure refrigerant flow channel 12 is attached to the outer periphery of the stem 37 to prevent refrigerant leakage from the high pressure refrigerant flow channel 13 to the low pressure refrigerant flow channel 12. O-ring for sealing. In the expansion valve 10 configured as described above, when the temperature of the low-pressure refrigerant flowing through the low-pressure refrigerant flow path 12 decreases, the temperature of the diaphragm 32 decreases, and the temperature-sensitive chamber 30 decreases.
The saturated vapor gas inside condenses on the inner surface of the diaphragm 32. Then, the pressure in the temperature-sensitive chamber 30 is reduced, and the diaphragm 32 is displaced inside the temperature-sensitive chamber 30, and the diaphragm receiving plate 33 is displaced in the axial direction of the rod 23 in the direction of escaping from the rod 23. Rod 23
Is pushed by the compression coil spring 17 and moves. As a result, the valve element 21 moves toward the valve seat 20 and the flow area of the high-pressure refrigerant is reduced, so that the flow rate of the refrigerant sent into the evaporator 1 is reduced. When the temperature of the low-pressure refrigerant flowing in the low-pressure refrigerant flow path 12 rises, the valve body 21 is pushed by the rod 23 and separated from the valve seat 20 by the operation reverse to the above, and the flow path area of the high-pressure refrigerant increases. Accordingly, the flow rate of the high-pressure refrigerant sent to the evaporator 1 increases. As described above, the temperature-sensitive chamber 30 and the rod 2 correspond to the temperature of the low-pressure refrigerant sent from the evaporator 1.
The amount of the high-pressure refrigerant sent to the evaporator 1 is controlled by opening and closing the valve body 20 through the operation of the third operation. However, the high-pressure refrigerant sent to the expansion valve 10 may cause pressure fluctuations on the upstream side for some reason, and the pressure fluctuations are transmitted to the expansion valve 10 using the high-pressure refrigerant liquid as a medium. You. When the refrigerant pressure on the upstream side of the valve element 21 rises due to pressure fluctuation, it acts in a direction to close the valve element 21. FIGS. 2 to 4 show the movement of the valve body 21 at that time.
Is pressed against the recess 22 by the urging force. Then, first, as shown in FIG. 2, the valve element 21 starts to move in a direction approaching the valve seat 20, and then, as shown in FIG. 3, the valve element 21 partially contacts the valve seat 20. Then, the valve body 21 is located at a position where the surface portion is fitted into the recess 22, and the recess 22 is formed eccentrically from the axial position of the rod 23.
2 is guided to a position deviated from the central axis position (that is, the central axis position of the valve seat 20), and the gap between the valve body 21 and the valve seat 20 is not completely closed. In order for the valve body 21 to be in the fully closed state shown in FIG. 4 from the state where the valve body 21 partially contacts the valve seat 20 and is not completely closed, the valve body 21 must be removed from the recess 22. It is necessary to move the valve seat 20 to the center position of the valve seat 20. However, since the valve body 21 is pressed by the urging force of the compression coil spring 17 to form a so-called click mechanism, the recess 22
In order for 1 to come out, it is necessary to press the valve body 21 against the valve seat 20 with a larger force. Therefore, if the pressure in the high-pressure refrigerant flow path 13 rises for a short time, the space between the valve element 21 and the valve seat 20 is not completely closed, and the pressure does not develop into a large pressure fluctuation in the high-pressure refrigerant flow path 13. No vibration or abnormal noise occurs. According to the present invention, a recess is formed in the end surface of the rod abutting on the valve body for guiding the valve body pressed against the valve body to a position deviated from the center of the valve seat. Due to the formation, the recess becomes a so-called click mechanism, and the valve body needs to be pressed against the valve seat with a larger force in order for the valve body to come out of the recess. As a result, when the pressure in the high-pressure refrigerant flow path rises for a short time, the valve does not completely close and does not develop into large pressure fluctuations in the high-pressure refrigerant flow path, so that no vibration or noise occurs.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a longitudinal sectional view of an expansion valve according to an embodiment of the present invention. FIG. 2 is a partial cross-sectional view of the valve according to the embodiment of the present invention in a slightly opened state. FIG. 3 is a partial cross-sectional view showing a state where the valve according to the embodiment of the present invention is almost closed. FIG. 4 is a partial cross-sectional view showing a state in which the valve according to the embodiment of the present invention is completely closed. FIG. 5 is a longitudinal sectional view of a conventional expansion valve. FIG. 6 is a partial cross-sectional view of a conventional expansion valve in a state where a valve is slightly opened. FIG. 7 is a partial cross-sectional view showing a state where a valve of a conventional expansion valve is almost closing. FIG. 8 is a partial cross-sectional view showing a state where a valve of a conventional expansion valve is completely closed. [Description of Signs] 1 Evaporator 10 Expansion valve 13 High-pressure refrigerant flow path 15 Restriction hole 17 Compression coil spring 20 Valve seat 21 Valve body 22 Recess 23 Rod 30 Thermosensitive chamber

Claims (1)

(57) [Claims 1] A throttle hole formed by narrowing a cross-sectional area in the middle of a high-pressure refrigerant flow path through which a high-pressure refrigerant fed into an evaporator is formed, and an upstream opening of the throttle hole. A spherical valve element disposed so as to face from the upstream side to a valve seat formed at the mouth of the portion, and urging means for urging the valve element from the upstream side toward the valve seat; It is interposed between the temperature sensing part that operates according to the temperature of the low-pressure refrigerant sent from the evaporator and the valve body, is loosely inserted into the throttle hole, and one end is not fixed to the valve body. An expansion valve provided with an abutting rod, wherein the valve body is opened and closed with respect to the valve seat by the movement of the temperature sensing portion via the rod; and an end surface of the rod abutting on the valve body. And a valve body pressed against the urging means by the urging means. An expansion valve, wherein a recess is formed for guiding to a position deviated from the center of the expansion valve.