JPH08210734A - Temperature type expansion valve - Google Patents

Abstract

PURPOSE: To provide a temperature type expansion valve which is constituted to perform stable valve operation without increasing a manufacturing cost. CONSTITUTION: A valve block 8 constituting an expansion valve 1 body is provided with a second flow passage 7 through which a refrigerant fed from a refrigerant vaporizer 5 flows. The temperature of the refrigerant flowing through the second flow passage 7 is transmitted through a transmission rod 18 to a diaphragm 12 forming one wall surface of a temperature-sensitive chamber 14. The transmission rod 18 comprises a temperature-sensitive part 18b exposed to a refrigerant flowing through a second flow passage 7, a return part 18c having diameter larger than that of the temperature-sensitive part 18b, and a head part 18a having diameter further larger than that of the return part 18c, and the upper end surface of a head part 18a is adhered to the diaphragm 12. The return part 18c is positioned on the inner periphery of an opening hole 16 communicated with the second flow passage 7, an outer periphery is expanded to a position approaching the inner peripheral surface of the opening hole 16, and a difference in a level is produced between the temperature- sensitive part 18b and the return part.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a temperature type expansion which automatically adjusts the flow rate of the refrigerant sent to the refrigerant evaporator in response to the temperature change of the refrigerant flowing from the refrigerant evaporator of the refrigeration cycle to the refrigerant compressor. Regarding the valve.

[0002]

2. Description of the Related Art Conventionally, there is a gas charge expansion valve in which saturated vapor gas is enclosed in a sensitive greenhouse where a diaphragm forms one wall surface. In this expansion valve, the temperature of the refrigerant (the refrigerant flowing from the refrigerant evaporator to the refrigerant compressor) flowing through the low pressure refrigerant passage formed in the valve block is transmitted to the diaphragm via the rod, but flows through the low pressure refrigerant passage. If the temperature change of the refrigerant is transmitted to the diaphragm too quickly, small pulsation generated in the refrigerant such as a slight change in the degree of superheat of the refrigerant is directly transmitted to the opening / closing operation of the valve mechanism, so that the valve operation becomes very unstable.

Therefore, the expansion valve disclosed in Japanese Patent Laid-Open No. 157405/1993 has a space between the low-pressure refrigerant passage and the greenhouse (diaphragm) in order to regulate the amount of the refrigerant flowing from the low-pressure refrigerant passage to the greenhouse-sensitive side. An intermediate plug body made of rubber or plastic having low thermal conductivity is provided. As a result, it is possible to delay the time until the temperature change of the refrigerant flowing through the low-pressure refrigerant passage is transmitted to the temperature-sensing greenhouse, so that it is not sensitive to a small (small) temperature change of the refrigerant flowing through the low-pressure refrigerant passage. Therefore, stable valve operation can be performed.

[0004]

However, in the expansion valve disclosed in the above publication, since an intermediate plug is newly added, it takes time and effort for assembling, which causes an increase in manufacturing cost. The problem you said arises. The present invention has been made based on the above circumstances, and an object of the present invention is to provide a thermal expansion valve capable of performing stable valve operation without increasing manufacturing cost.

[0005]

The present invention has the following features to attain the object mentioned above. In claim 1,
A valve mechanism that adjusts the flow rate of the refrigerant to be sent to the refrigerant evaporator by changing the valve opening degree, a sensing chamber in which one wall is formed by a diaphragm, and saturated vapor is enclosed inside, and a sent from the refrigerant evaporator. A low-pressure refrigerant passage through which a refrigerant is passed, and an opening hole communicating from the low-pressure refrigerant passage to the diaphragm side are inserted to transmit the temperature of the refrigerant flowing through the low-pressure refrigerant passage to the diaphragm, and the displacement of the diaphragm is transferred to the valve mechanism. In the temperature type expansion valve having a transmission rod for transmitting to the transmission rod, the transmission rod has a return portion whose outer diameter is enlarged at a portion passing through the inner periphery of the opening hole until it comes close to the inner peripheral surface of the opening hole. It is characterized by being provided.

According to a second aspect, in the thermal expansion valve according to the first aspect, the transmission rod has a step between the outer peripheral surface of the temperature sensing portion and the outer peripheral surface of the return portion that pass through the low pressure refrigerant passage. Is provided.

According to a third aspect of the present invention, in the thermal expansion valve according to the first or second aspect, a portion of the transmission rod on the diaphragm side of the return portion expands in a radial direction beyond an outer diameter of the return portion. It is characterized by being.

According to a fourth aspect of the present invention, in the thermal expansion valve according to the first or second aspect, the transmission rod is radially inside the opening on the diaphragm side of the opening and is larger than the outer diameter of the return portion. It is characterized in that an enlarged second return portion is provided.

[0009]

In the temperature type expansion valve of the present invention having the above-mentioned structure, the low pressure (the pressure of the refrigerant flowing through the low pressure refrigerant passage) acts on the diaphragm through the opening hole through which the transmission rod is inserted. However, since the return portion provided on the transmission rod has an enlarged outer diameter until it is close to the inner peripheral surface of the opening hole, the refrigerant flowing through the low-pressure refrigerant passage passes through the opening hole (a gap with the return portion). The amount that enters the diaphragm side is small.

That is, since the gap (gap with the return portion) formed on the inner circumference of the opening hole is small, and the refrigerant which tries to pass through the opening hole along the transmission rod is repelled by the return portion, the above-mentioned gap is generated. It can be said that the effect of the refrigerant temperature transmitted to the diaphragm (greenhouse) by the refrigerant passing through is small.
Therefore, the temperature transmitted to the diaphragm is dominated by the temperature transmitted via the transmission rod, so that a stable valve operation can be performed without sensitively reacting to a small temperature change of the refrigerant flowing through the low-pressure refrigerant passage. .

In the second aspect, the temperature sensing portion passing through the low pressure refrigerant passage (the portion exposed to the refrigerant flowing inside the low pressure refrigerant passage).
A step is provided between the outer peripheral surface of the and the outer peripheral surface of the return portion. That is, the return portion is enlarged substantially at right angles to the outer peripheral surface of the temperature sensing portion. For this reason, most of the refrigerant that attempts to pass through the opening along the transmission rod is repelled by the return portion.

According to the third aspect of the present invention, the portion closer to the diaphragm than the return portion is enlarged in the radial direction beyond the outer diameter of the return portion. That is, since the volume of the transfer rod increases and the heat capacity increases, the transfer time of the refrigerant temperature transferred to the diaphragm via the transfer rod becomes longer. As a result, more stable valve operation can be performed.

In the fourth aspect, the second return portion can prevent the refrigerant that could not be prevented from entering the return portion provided on the inner periphery of the opening hole. That is, it is possible to prevent the refrigerant, which tends to enter the diaphragm side along the transmission rod, in two stages of the return portion and the second return portion. Further, since the volume of the transmission rod is increased and the heat capacity is increased by providing the second return portion, the transmission time of the refrigerant temperature transmitted to the diaphragm via the transmission rod is increased. become longer. As a result, more stable valve operation can be performed.

As described above, according to the temperature type expansion valve of the present invention, stable valve operation can be obtained with a simple structure in which the return portion is provided on the transmission rod. In other words, there is no need to newly add another component as in the conventional case, and therefore, there is no problem in assembling, so that an increase in manufacturing cost can be suppressed.

[0015]

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)
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 has a substantially rectangular parallelepiped shape. The first flow path 6 is a passage for decompressing and expanding the refrigerant guided from the receiver 4 and sending it to the refrigerant evaporator 5, and is provided on the lower side of the valve block 8 (the lower side in FIG. 1) and The high pressure passage 6a communicates with the outlet side, the low pressure passage 6b communicates with the inlet side of the refrigerant evaporator 5, and the communication hole 6c communicates the high pressure passage 6a with the low pressure passage 6b.

The high pressure passage 6a is bored from one end surface (right end surface in FIG. 1) of the valve block 8 to the middle of the valve block 8, and the low pressure passage 6b is formed from the other end surface of the valve block 8 to the valve block 8. Has been drilled up to the middle. However, the high pressure passage 6
a and the low pressure passage 6b are in the longitudinal direction of the valve block 8 (see FIG.
(Up and down direction) of the.

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 valve body 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.
A receiving seat 11 is attached via the through hole 11, and a greenhouse 14 formed of a diaphragm 12 and a housing 13 is provided to the receiving seat 11. The receiving seat 11 is screwed onto the inner peripheral surface of an opening 15 formed at the center of the upper end of the valve block 8. The opening 15 communicates with the second flow path 7 through an opening 16 that opens at the center of the bottom surface. 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 thin metal plate (for example, a stainless steel plate having a thickness of about 0.1 mm), and is supported so as to be displaceable according to the pressure fluctuation in the greenhouse 14. It should be noted that the sensitive room 14 has a sealed tube 17
The saturated vapor (for example, the same as the refrigerant gas used in the refrigeration cycle) is enclosed by. The end portion of the sealing tube 17 is sealed after the saturated vapor gas is completely sealed.

The valve block 8 has a transmission rod 1 for transmitting the temperature of the refrigerant flowing through the second flow path 7 to the diaphragm 12.
8, components such as a valve body 9 that interlocks with the displacement of the diaphragm 12 via the transmission rod 18 and the connecting rod 19, a spring 20 that urges the valve body 9, and an adjusting screw 21 that adjusts the mounting load of the spring 20. Is built in.

The transmission rod 18 is made of a material having excellent thermal conductivity (eg, brass, aluminum, etc.), passes through the opening 15 and the opening hole 16 and the second flow path 7, and passes through the center of the valve block 8. O-ring 2 in the vertical hole 22 formed in the
It is slidably inserted through 3.

The transmission rod 18 is enlarged in the radial direction and is accommodated in the opening portion 15, a temperature sensing portion 18b exposed to the refrigerant flowing through the second flow path 7, and the head portion 18a and the temperature sensing portion 18b. And a return portion 18c located on the inner periphery of the opening hole 16 between and. However, the return part 18c is the temperature sensing part 18b.
The outer diameter is larger, the outer circumference is enlarged until it is close to the inner circumferential surface of the opening hole 16, and there is a substantially right-angled step with the temperature sensing portion 18b. The outer diameter of the head portion 18a is larger than that of the return portion 18c, the outer circumference of the head portion 18a is enlarged until the inner peripheral surface of the opening portion 15 is close to the return portion 18c, and the head portion 18a has a substantially right-angled step.

The upper end surface of the head portion 18a has the second flow path 7
In order to transmit the temperature of the refrigerant flowing through to the diaphragm 12, it is in close contact with the lower surface of the diaphragm 12. Further, the outer periphery of the upper end of the head portion 18a is spread over the umbrella, and the receiving seat 11
By contacting with, the downward movement in the figure (that is, the displacement of the diaphragm 12) is restricted.

The valve body 9 is attached to the lower end of a connecting rod 19 connected to the transmission rod 18, and is arranged upstream of the communication hole 6c (high pressure passage 6a side). The valve body 9 is integrally displaced with the transmission rod 18 and the connecting rod 19 to change the opening degree of the communication hole 6c, that is, the valve opening degree. The connecting rod 19 is
The low pressure passage 6b is traversed through a through hole (not shown) which penetrates from the vertical hole 22 to the low pressure passage 6b, and the communication hole 6
It passes through c and reaches the high pressure passage 6a side. An O-ring 23 arranged in the vertical hole 22 hermetically seals between the second flow path 7 and the low-pressure passage 6b.

The spring 20 is held by an adjusting screw 21 attached to the lower end of the valve block 8 and attaches the valve body 9 upward (in a direction in which the valve opening becomes smaller) via a valve receiving member 24. I am energetic. The adjusting screw 21 is an O-ring 2
The valve opening pressure (mounting load of the spring 20) is variable by being screwed to the lower end of the valve block 8 via 5 and 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 to is determined by the valve opening, that is, the position of the valve body 9 with respect to the valve seat 6d. The valve body 9 has a pressure of the greenhouse 14 that urges the diaphragm 12 downward in the drawing, a biasing force of a spring 20 that biases the diaphragm 12 upward in the drawing, and a low pressure (pressure of the refrigerant flowing in the second flow path 7). )
And move to a balanced position. The low-pressure pressure acts on the lower surface of the diaphragm 12 through the opening hole 16 and the opening 15 that open to the second flow path 7.

When the temperature inside the passenger compartment rises and the refrigerant evaporates rapidly in the refrigerant evaporator 5, the superheat degree at the outlet of the refrigerant evaporator 5 increases and the refrigerant flowing through the second flow path 7 of the expansion valve 1 increases. Temperature rises. As a result, the temperature of the refrigerant is changed to the transmission rod 18
Further, the temperature of the greenhouse 14 is transmitted to the greenhouse 14 via the diaphragm 12 and the temperature of the greenhouse 14 rises, so that the pressure of the greenhouse 14 rises to the saturated pressure of the elevated temperature.
As a result, the diaphragm 12 is pushed down, the valve body 9 moves downward in the drawing via the transmission rod 18 and the connecting rod 19, and the valve opening increases (the gap between the valve body 9 and the valve seat 6d increases. Therefore, the flow rate of the refrigerant sent to the refrigerant evaporator 5 increases.

When the temperature inside the vehicle compartment decreases and the 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 greenhouse 14 decreases. Conversely, the pressure in the greenhouse 14 is lowered and the diaphragm 12 is pushed up, the valve body 9 moves upward in the drawing and the valve opening becomes small (the gap between the valve body 9 and the valve seat 6d is reduced). As a result, the flow rate of the refrigerant sent to the refrigerant evaporator 5 decreases.

(Characteristics and effects of the first embodiment) In the above operation, the refrigerant pressure (low pressure) of the second flow passage 7 acts on the lower surface of the diaphragm 12 through the opening hole 16 and the opening portion 15. Returning part 1 provided at 18
Since 8c has an outer diameter enlarged until it comes close to the inner peripheral surface of the opening hole 16, the refrigerant flowing through the second flow path 7 passes through the opening hole 16 (a gap between the return portion 18c) and the diaphragm 1
The amount that enters the 2 side is small.

That is, the gap formed in the inner periphery of the opening 16 (the gap with the return portion 18c) is small, and the transmission rod 1
Since the refrigerant (mainly the liquid-phase refrigerant) that is about to pass through the opening hole 16 along 8 is repelled at the return portion 18c, the diaphragm 12 (the greenhouse 1
It can be said that the influence of the refrigerant temperature transmitted to 4) is small. In particular, since the liquid-phase refrigerant has a larger influence of heat transfer than the gas-phase refrigerant, it can be said that the effect of preventing the infiltration of the liquid-phase refrigerant is large.

Therefore, the temperature transmitted to the greenhouse 14 is dominated by the temperature transmitted via the transmission rod 18. The transmission rod 18 has a radially expanded head portion 18a.
Because of the large heat capacity, the time taken for the temperature of the refrigerant flowing through the second flow path 7 to be transmitted to the diaphragm 12 becomes long. As a result, stable valve operation can be performed without hypersensitivity to a small temperature change of the refrigerant flowing through the second flow path 7.

(Second Embodiment) FIG. 2 is an overall sectional view of a thermal expansion valve 1 according to the second embodiment. In the present embodiment, the return portion 18c is provided only in the portion corresponding to the opening hole 16 in the middle of the transmission rod 18. In the present embodiment, the time until the heat is transferred to the diaphragm 12 is slightly shortened as the heat capacity of the transfer rod 18 is reduced, but the difference in the effect due to the heat capacity is smaller than the effect due to the return portion 18c. There is almost no problem in practical use.

That is, the time until the temperature of the refrigerant flowing through the second flow path 7 is transmitted to the diaphragm 12 is the opening hole 16
The greater the amount of the refrigerant flowing through to the diaphragm 12 side, the shorter the time. Therefore, also in the present embodiment, the return portion 18c provided on the transmission rod 18 can bounce off the refrigerant (mainly the liquid-phase refrigerant) that is about to pass through the opening 16 to reduce the amount of the refrigerant entering the diaphragm 12 side. Therefore, similar to the first embodiment, stable valve operation can be performed without hypersensitivity to a small temperature change of the refrigerant flowing through the second flow path 7.

(Third Embodiment) FIG. 3 is an overall sectional view of a thermal expansion valve 1 according to the third embodiment. In this embodiment, in addition to the return portion 18c described in the second embodiment, a second return portion 18d is provided inside the opening 15. This second
The return portion 18d has a larger outer diameter than the return portion 18c and is enlarged until it comes close to the inner peripheral surface of the opening 15. As a result, even if there is a refrigerant that passes through the return hole 18c and passes through the opening hole 16, the diaphragm 12 is not discharged by the second return portion 18d.
Since the invasion of the refrigerant into the side can be suppressed, the opening hole 1
The diaphragm 12 (the greenhouse 1
It is possible to reduce the influence of the refrigerant temperature transmitted to 4). Further, since the volume of the transfer rod 18 increases and the heat capacity increases by providing the second return portion 18d (compared to the second embodiment), the heat is transferred to the diaphragm 12 via the transfer rod 18. The transmission time of the refrigerant temperature becomes long, and stable valve operation can be performed.

[Brief description of drawings]

FIG. 1 is an overall sectional view of a thermal expansion valve (first embodiment).

FIG. 2 is an overall sectional view of a thermal expansion valve (second embodiment).

FIG. 3 is an overall sectional view of a thermal expansion valve (third embodiment).

[Explanation of symbols]

 1 Temperature Expansion Valve 5 Refrigerant Evaporator 6d Valve Seat (Valve Mechanism) 7 Second Flow Path (Low Pressure Refrigerant Passage) 9 Valve Body (Valve Mechanism) 12 Diaphragm 14 Greenhouse 15 Opening 16 Opening Hole 18 Transfer Rod 18b Temperature Sensitive Part 18c Return part 18d Second return part

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

Claims (4)

[Claims] 1. A valve mechanism for adjusting a flow rate of a refrigerant to be sent to a refrigerant evaporator by varying a valve opening degree, a greenhouse in which one wall is formed by a diaphragm, and saturated vapor is sealed inside, and the refrigerant evaporation. A low-pressure refrigerant passage through which the refrigerant sent from the container is passed, and an opening hole communicating from this low-pressure refrigerant passage to the diaphragm side, and transmitting the temperature of the refrigerant flowing through the low-pressure refrigerant passage to the diaphragm, and In a thermal expansion valve including a transmission rod that transmits displacement to the valve mechanism, the transmission rod has an outer diameter that increases at a portion passing through the inner circumference of the opening hole until the outer diameter approaches the inner circumference surface of the opening hole. A thermal expansion valve, characterized in that it is provided with an inverted return section. 2. The thermal expansion valve according to claim 1, wherein the transmission rod is provided with a step between an outer peripheral surface of the temperature sensing portion passing through the low pressure refrigerant passage and an outer peripheral surface of the return portion. The temperature type expansion valve is characterized by having. 3. The thermal expansion valve according to claim 1, wherein a portion of the transmission rod that is closer to the diaphragm than the return portion is radially expanded to be larger than an outer diameter of the return portion. A temperature type expansion valve characterized in that 4. The thermal expansion valve according to claim 1 or 2, wherein the transmission rod is expanded in the opening on the diaphragm side of the opening in the radial direction more than the outer diameter of the return portion. A temperature type expansion valve characterized in that a second return portion is provided.