JPH08193769A - Temperature type expansion valve - Google Patents

Abstract

PURPOSE: To prevent a temperature type expansion valve from being erroneously operated owing to the influence of external temperature without being influenced by mounting attitude. CONSTITUTION: A temperature sensitive chamber 14 is provided in a reception pedestal 11 fixed to an upper part of a valve block 8, the temperature sensitive chamber being composed of a diaphragm 12 and a housing 13. The temperature sensitive chamber 14 includes a fluid reservoir chamber 16 in which there are stored and kept condensed liquid droplets of saturated vapor gas encapsulated in the temperature sensitive chamber 14 when it is condensed and liquefied. The fluid reservoir chamber 16 is formed with a partition plate 17 mounted by permitting its outer peripheral part to be held between the diaphragm 12 and the housing 13. The partition plate 17 permits its entire central part to be protruded toward the housing 13 side with respect to the outer peripheral part thereof in close contact with the diaphragm 12 whereby a flattened space is formed between it and the diaphragm 12 as the fluid reservoir chamber 16.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal expansion valve for adjusting the flow rate of the refrigerant sent to the refrigerant evaporator according to the temperature of the refrigerant flowing out from the refrigerant evaporator.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 8, a greenhouse 120 is provided at the end of a valve block 110, and
Gas charge expansion valve 10 in which saturated vapor gas is sealed in 20
There is 0. Since the expansion valve 100 is arranged in an atmosphere having a higher temperature than the flowing refrigerant, the surface of the diaphragm 130 has the lowest temperature among the wall surfaces forming the greenhouse 120.
Therefore, when the temperature of the refrigerant transmitted to the diaphragm 130 via the rod 140 decreases, the saturated vapor gas filled in the greenhouse 120 is condensed on the inner surface of the diaphragm 130 and liquefied.

Therefore, the diaphragm 130 has the greenhouse 12
There is no problem if the expansion valve 100 is arranged so as to be the lower surface of 0, but in other cases, for example, the expansion valve 10 such that the diaphragm 130 is the upper surface of the greenhouse 120.
When 0 is arranged, the liquid droplets condensed by the diaphragm 130 drop onto the inner surface of the outer wall member 150 forming the greenhouse 120. Since the outer wall member 150 is exposed to a high temperature atmosphere, the pressure in the greenhouse 120 is rapidly increased by evaporating the dropped liquid droplets again. However, since the saturated vapor pressure due to the temperature of the surface of the diaphragm 130 is lower than that pressure, it is condensed again on the inner surface of the diaphragm 130.

As a result, the pressure inside the greenhouse 120 periodically fluctuates, the valve mechanism 160 operates, and the flow rate of the refrigerant flowing through the refrigerating cycle constantly fluctuates, and the refrigerating cycle becomes unstable. Will end up. Therefore, in the expansion valve 100 of this type, it is necessary to arrange the expansion valve 100 so that the diaphragm 130 is always on the lower surface of the greenhouse 120, and the mounting posture of the expansion valve 100 is limited.

In view of this, Japanese Patent Laid-Open No. 5-26541 proposes an expansion valve in which an adsorbing means for adsorbing liquid drops is added to the inner surface of the diaphragm. According to this, since the condensed droplets are adsorbed by the adsorption means and are always held on the surface portion of the diaphragm, even if the expansion valve is arranged so that the diaphragm is on the upper surface of the greenhouse, the condensed droplets are Does not fall and re-evaporate. Therefore, the mounting posture of the expansion valve is not limited.

[0006]

However, in the structure in which the adsorbing means is added to the inner surface of the diaphragm as described above, the adsorbent used as the adsorbing means may be peeled off from the diaphragm, in which case the desired effect cannot be obtained. You won't get it. Further, if the peeled adsorbent drops and enters between the diaphragm and the outer wall member, the operation of the diaphragm is affected. Furthermore, it may lead to the diaphragm being damaged. The present invention has been made based on the above circumstances, and its purpose is to be independent of the mounting posture.
It is to provide a thermal expansion valve that prevents malfunction due to the influence of external temperature.

[0007]

The present invention has the following features to attain the object mentioned above. In claim 1,
A greenhouse which is filled with saturated vapor gas, forms a wall surface of the greenhouse, and a diaphragm which is displaced according to the pressure fluctuation in the greenhouse, and the temperature of the refrigerant flowing out from the refrigerant evaporator to the diaphragm. In thermal expansion provided with heat transfer means for transmitting and a valve mechanism for varying the valve opening degree according to the displacement of the diaphragm, a liquid storage chamber for accumulating the condensed droplets of the saturated vapor gas in the greenhouse. And the liquid storage chamber is insulated from the outer wall of the greenhouse.

According to a second aspect of the present invention, in the thermal expansion valve according to the first aspect, the liquid storage chamber is formed between the diaphragm and the outer wall by a plate member sandwiched between the diaphragm and the diaphragm. It is characterized by

According to a third aspect of the present invention, in the thermal expansion valve according to the first aspect, the liquid storage chamber is formed by a plate-shaped member provided in thermal contact with the diaphragm. To do.

[0010]

In the temperature type expansion valve of the present invention having the above structure, the liquid storage chamber formed inside the greenhouse is insulated from the outer wall of the greenhouse. Therefore, the condensed droplets of the saturated vapor gas in the greenhouse are collected and held in the liquid storage chamber without touching the outer wall (inner surface) of the greenhouse. As a result, the once condensed droplets do not re-evaporate by touching the outer wall other than the diaphragm, and it is possible to prevent malfunction due to the influence of the external temperature. Further, since the liquid droplets are held in the liquid storage chamber, the mounting posture of the thermal expansion valve is not limited.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of the thermal expansion valve of the present invention will be described with reference to the drawings. (First Embodiment) FIG. 1 is an overall sectional view of a thermal expansion valve. Thermal expansion valve 1 of the present embodiment (hereinafter referred to as expansion valve 1)
Is a refrigerant compressor 2, a refrigerant condenser 3,
A refrigeration cycle is configured with the receiver 4 and the refrigerant evaporator 5.

The expansion valve 1 includes a first flow path 6 and a second flow path 7.
The valve block 8 is formed in a substantially rectangular parallelepiped shape. The first flow path 6 is a passage for decompressing and expanding the liquid refrigerant guided from the receiver 4 to the refrigerant evaporator 5, and is provided on the lower side of the valve block 8 (lower side in FIG. 1). A high pressure passage 6a leading to the outlet side, a low pressure passage 6b leading to the inlet side of the refrigerant evaporator 5, and a communication hole 6c communicating the high pressure passage 6a and the low pressure passage 6b. The high pressure passage 6a is formed from one end surface (right end surface in FIG. 1) of the valve block 8 to the valve block 8
The low pressure passage 6b is drilled from the other end surface of the valve block 8 to the middle of the valve block 8.
However, the high pressure passage 6a and the low pressure passage 6b are connected to the valve block 8
Are provided so as to be displaced in the longitudinal direction (vertical direction in FIG. 1).

The communication hole 6c forms an orifice of the first flow passage 6, and connects the high pressure passage 6a and the low pressure passage 6b in the longitudinal direction of the valve block 8. A conical valve seat 6d that forms a valve mechanism with the ball valve 9 described below is formed on the high pressure passage 6a side of the communication hole 6c. The second flow path 7 is a low-pressure refrigerant passage through which the refrigerant evaporated in the refrigerant evaporator 5 passes, one end of which is connected to the outlet of the refrigerant evaporator 5, and the other end of which is connected to the inlet of the refrigerant compressor 2. The second flow path 7 is provided on the upper side of the valve block 8 so as to penetrate from one end surface to the other end surface of the valve block 8.

At the upper end of the valve block 8, an O-ring 10 is provided.
The receiving seat 11 is fixed to the receiving seat 11, and the receiving room 11 is provided with the greenhouse 14 formed of the diaphragm 12 and the housing 13. The receiving seat 11 and the housing 13 are both made of a thick metal plate, and their outer peripheral portions sandwich the peripheral edge portion of the diaphragm 12 and are airtightly joined. The diaphragm 12 is provided by a flexible metal thin plate (for example, a stainless steel plate having a plate thickness of about 0.1 mm),
It is supported so as to be displaceable according to pressure fluctuations in the greenhouse 14. The saturated greenhouse gas (for example, the same as the refrigerant gas used in the refrigeration cycle) is sealed in the greenhouse 14 by a sealing tube 15. The end portion of the sealing tube 15 is sealed after the saturated vapor gas is completely sealed.

Further, the greenhouse 14 is provided with a liquid storage chamber 16 for storing and holding the condensed droplets when the saturated vapor gas is condensed and liquefied. This reservoir 16
As shown in FIG. 2, the outer peripheral portion is formed by a partition plate 17 (a plate-shaped member of the present invention) that is attached by being sandwiched between the diaphragm 12 and the housing 13. The partition plate 17 has a central portion that is convex toward the housing 13 side with respect to the outer peripheral portion that is in close contact with the diaphragm 12, and forms a flat space between the partition plate 17 and the diaphragm 12, and this space is the liquid storage chamber 16 It is said that

However, the liquid storage chamber 16 is so constructed that the housing 1 is not affected by the external temperature through the housing 13.
It is insulated with 3. In other words, the partition plate 17 is not limited to the outer peripheral portion sandwiched between the diaphragm 12 and the housing 13, and especially between the diaphragm 12 and the liquid storage chamber 16
In the convex-shaped portion that forms the space, a gap is maintained between the housing 13 and the housing 13 without contacting the housing 13. A vent hole 17a is formed in the center of the partition plate 17 so that the saturated vapor gas can flow through the liquid storage chamber 16. The opening peripheral edge of the vent hole 17a is bent toward the diaphragm 12 side.

In the valve block 8, a heat transfer rod 18 (heat transfer means of the present invention) for transferring the temperature of the refrigerant flowing through the second flow path 7 to the diaphragm 12, a ball valve 9 interlocked with the displacement of the diaphragm 12, Parts such as an adjusting spring 19 for urging the ball valve 9 are incorporated. The heat transfer rod 18 is made of a material having excellent thermal conductivity (for example, brass, aluminum, etc.), and is slidable through a vertical hole 20 formed in the central portion of the valve block 8 via an O-ring 21. Has been inserted into. That is, since the heat transfer rod 18 is arranged across the second flow path 7,
It is exposed to the refrigerant flowing through the second flow path 7. The head 18a of the heat transfer rod 18 is brought into contact with the lower surface of the diaphragm 12,
It is enlarged in the radial direction to obtain the contact area with the diaphragm 12.

The ball valve 9 is attached to the lower end of a rod 22 connected to the heat transfer rod 18, and is arranged on the upstream side (high pressure passage 6a side) of the communication hole 6c. The ball valve 9 is integrally displaced with the heat transfer rod 18 and the rod 22 to change the opening degree of the communication hole 6c, that is, the valve opening degree. The adjusting spring 19 is held by an adjusting screw 23 attached to the lower end of the valve block 8, and urges the ball valve 9 upward (in a direction in which the valve opening becomes smaller) via the valve receiving member 24. ing. Adjusting screw 23
Is screwed to the lower end of the valve block 8 via the O-ring 25, and the valve opening pressure (mounting load of the adjusting spring 19) is varied by adjusting the mounting position (screwed position) to the valve block 8. .

Next, the operation of the expansion valve 1 of this embodiment will be described. High pressure passage 6a through low pressure passage 6b through communication hole 6c
The flow rate of the refrigerant flowing into is determined by the valve opening, that is, the position of the ball valve 9 with respect to the valve seat 6d. The ball valve 9 includes a pressure of the greenhouse 14 for urging the diaphragm 12 downward in the figure, an urging force of the adjusting spring 19 for urging the diaphragm 12 upward in the figure, and a low pressure (for the refrigerant flowing through the second flow path 7). Pressure) moves to a position that is balanced with.

Therefore, when the temperature in the passenger compartment rises and the refrigerant vaporizes rapidly in the refrigerant evaporator 5, the degree of superheat at the outlet of the refrigerant evaporator 5 becomes high and the second flow path 7 of the expansion valve 1 flows. The temperature of the flowing refrigerant rises. As a result, the refrigerant temperature is transmitted to the diaphragm 12 via the heat transfer rod 18, and the temperature of the diaphragm 12 rises, so that the diaphragm 1
The liquid droplets condensed on the surface of No. 2 are evaporated and the pressure of the greenhouse 14 rises. As a result, the diaphragm 12 is pushed down, and the ball valve 9 is passed through the heat transfer rod 18 and the rod 22.
Moves downward in the figure, and the valve opening degree increases (the gap with the valve seat 6d increases), so that the refrigerant flow rate sent to the refrigerant evaporator 5 increases.

When the temperature inside the vehicle compartment decreases and the degree of superheat at the outlet of the refrigerant evaporator 5 decreases, the temperature of the refrigerant flowing through the second flow path 7 decreases and the temperature of the diaphragm 12 decreases. Fourteen saturated vapor gases condense on the surface of diaphragm 12. As a result, contrary to the above-described operation, the pressure in the greenhouse 14 is lowered and the diaphragm 12 is pushed up, the ball valve 9 moves upward in the drawing, and the valve opening becomes small (a gap with the valve seat 6d is generated. As a result, the flow rate of the refrigerant sent to the refrigerant evaporator 5 decreases.

(Effects of the Embodiment) According to the expansion valve 1 of this embodiment, the liquid droplets condensed on the surface of the diaphragm 12 as the temperature of the diaphragm 12 decreases depend on the mounting posture of the expansion valve 1. Not, always the liquid storage chamber 1 in the greenhouse 14
Held at 6. For example, when the expansion valve 1 is mounted in the posture shown in FIG. 1, that is, when the diaphragm 12 forms the lower surface of the greenhouse 14, the liquid condensed on the surface of the diaphragm 12 as in the conventional expansion valve 1. The drops are retained on the surface of the diaphragm 12 as they are.

When the expansion valve 1 is mounted upside down with respect to the posture shown in FIG. 1, that is, when the diaphragm 12 forms the upper surface of the greenhouse 14, the liquid condensed on the surface of the diaphragm 12 is used. The drops fall under their own weight,
It does not fall to the housing 13 of the greenhouse 14,
As shown in FIG. 3, most of the droplets are retained on the partition plate 17 located below the diaphragm 12. This time,
A ventilation hole 17a is formed in the center of the partition plate 17, but since the opening peripheral edge of the ventilation hole 17a is bent toward the diaphragm 12 side, the partition plate 1
The liquid droplets held in 7 do not fall from the ventilation hole 17a.

Further, when the expansion valve 1 is mounted in a sideways posture, that is, when the diaphragm 12 is in an upright state, the liquid droplets condensed on the surface of the diaphragm 12 travel down the surface of the diaphragm 12. Although it falls, it does not reach the housing 13, and as shown in FIG. 4, it is retained and retained in the liquid reservoir chamber 16 formed by the partition plate 17. As described above, no matter how the expansion valve 1 is mounted, the liquid droplets condensed on the surface of the diaphragm 12 do not directly contact the housing 13 and accumulate in the liquid storage chamber 16 formed by the partition plate 17. Retained. Therefore, the once-condensed liquid droplets do not come into contact with the housing 13 and re-evaporate, so that it is possible to prevent malfunction due to the influence of the external temperature.

(Second Embodiment) FIG. 5 is a sectional view showing a mounting state of the partition plate 17. In this embodiment, as shown in FIG.
The inner volume of the liquid storage chamber 16 is expanded by greatly expanding the central portion of the. According to this, it is effective against the vibration of the vehicle. That is, even if vibration of the vehicle occurs, the liquid storage chamber 1
The liquid does not easily spill from 6.

(Third Embodiment) FIG. 6 is a sectional view showing a mounting state of the partition plate 17. In this embodiment, as shown in FIG. 6, the tip of the enclosing tube 15 is joined (for example, brazed) to the partition plate 17 so that the liquid storage chamber 16 is hermetically sealed. According to the present embodiment, there is no risk of liquid spilling from the liquid storage chamber 16. In order to ensure the airtightness of the liquid storage chamber 16, the outer peripheral portion of the partition plate 17 has a housing 1
3, the diaphragm 12 and the receiving seat 11 must be welded all around at the same time, or must be sufficiently pressed and attached between the diaphragm 12 and the housing 13 so that saturated vapor gas is not vented. A heat insulating material (not shown) may be interposed between the sealed tube 15 and the housing 13 in order to suppress heat transfer from the housing 13.

(Fourth Embodiment) FIG. 7 is a sectional view showing a mounting state of the partition plate 17. In this embodiment, as shown in FIG. 7, the partition plate 17 is formed in a bowl shape.
The bottom may be joined to the center of the diaphragm 12 by spot welding or the like. In this case, the decrease in the temperature of the diaphragm 12 is transmitted to the partition plate 17, causing condensation on the inner surface of the partition plate 17, and the droplets are retained in the liquid storage chamber 16 formed by the partition plate 17 as it is.

[Brief description of drawings]

FIG. 1 is an overall sectional view of a thermal expansion valve.

FIG. 2 is a cross-sectional view showing a mounting state of a partition plate (first embodiment).

FIG. 3 is a cross-sectional view illustrating the operation of the partition plate (first embodiment).

FIG. 4 is a cross-sectional view illustrating the operation of the partition plate (first embodiment).

FIG. 5 is a cross-sectional view showing a mounting state of a partition plate (second embodiment).

FIG. 6 is a sectional view showing a mounting state of a partition plate (third embodiment).

FIG. 7 is a cross-sectional view showing a mounting state of a partition plate (fourth embodiment).

FIG. 8 is an overall sectional view of a thermal expansion valve according to a conventional technique.

[Explanation of symbols]

 1 Temperature Expansion Valve 5 Refrigerant Evaporator 6d Valve Seat (Valve Mechanism) 9 Valve Body (Valve Mechanism) 12 Diaphragm 13 Housing (Outer Wall) 14 Greenhouse 16 Liquid Storage Chamber 17 Partition Plate (Plate Member) 18 Heat Transfer Rod ( (Heat transfer means)

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Kenichi Fujiwara, 1-1, Showa-cho, Kariya city, Aichi Prefecture, Nihon Denso Co., Ltd.

Claims (3)

[Claims] 1. A greenhouse which is filled with saturated vapor gas, a diaphragm which forms one wall surface of the greenhouse and is displaced according to a pressure fluctuation in the greenhouse, and a refrigerant which flows out from a refrigerant evaporator. In a thermal expansion valve comprising a heat transfer means for transmitting a temperature to the diaphragm and a valve mechanism for varying a valve opening degree according to the displacement of the diaphragm, a liquid in which the saturated vapor gas is condensed in the greenhouse. A temperature type expansion valve characterized in that a liquid storage chamber for storing drops is formed, and the liquid storage chamber is insulated from the outer wall of the greenhouse. 2. The thermal expansion valve according to claim 1, wherein the liquid storage chamber is formed between the diaphragm and the outer wall by a plate member sandwiched between the diaphragm and the diaphragm. Thermal expansion valve characterized by. 3. The thermal expansion valve according to claim 1, wherein the liquid storage chamber is formed by a plate member provided in thermal contact with the diaphragm. Expansion valve.