JP2002350015A - Expansion valve and fitting structure thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an expansion valve being excellent in the contact of outlet piping of an evaporator with a temperature sensing tube and of a low cost. SOLUTION: A temperature sensing portion 12 detecting the temperature of the outlet piping 18 of the evaporator is formed by bending the fore end of the temperature sensing tube 11 of the expansion valve at one place at least, and this portion 12 is fastened and fixed to the outlet piping 18 by a band 19. According to this constitution, the length of the temperature sensing portion 12 being in contact with the outlet piping 18 is enlarged and the area of the contact with the outlet piping 18 can be increased. Therefore a heat conducting member for increasing the contact area is dispensed with and the cost can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an expansion valve and a mounting structure thereof, and more particularly, to an expansion valve used in a refrigeration cycle of an air conditioner for an automobile and a mounting of an expansion valve for mounting a temperature sensing tube of the expansion valve to an evaporator. Regarding the structure.

[0002]

2. Description of the Related Art An expansion valve is disposed on the inlet side of an evaporator of a refrigeration cycle, and changes the opening degree of the valve in accordance with the temperature of the refrigerant on the outlet side of the evaporator to change the flow rate of the refrigerant supplied to the evaporator. It has a function to control. In a so-called gas-filled expansion valve,
The distal end of the temperature-sensitive tube in which the temperature-sensitive refrigerant is sealed is brought into contact with the outlet-side pipe portion of the evaporator, the base end side is communicated with the airtight chamber, and a part of the airtight wall of the airtight chamber is formed by a diaphragm, The diaphragm drives a valve element for changing the flow path area of the throttle portion through which the high-pressure refrigerant passes before being sent to the evaporator.

In such a gas-filled expansion valve,
It is desirable that the tip of the thermosensitive tube is brought into contact with the outlet pipe of the evaporator with as large an area as possible. As a method for realizing this, for example, in Japanese Utility Model Application Laid-Open No. 6-56663, a part of the outer periphery of the temperature sensing tube is tightly covered with an elastic heat conductive member, and the heat conductive member is connected to the outlet pipe of the evaporator. It has been proposed to press against the outer peripheral surface.

[0004]

However, in the conventional expansion valve, a heat conducting member is used in order to increase the contact area between the temperature sensing portion of the temperature sensing tube and the outlet pipe of the evaporator. There is a problem that the heat conduction member increases the cost of the expansion valve.

The present invention has been made in view of the above points, and provides an expansion valve capable of increasing a contact area with an outlet pipe of an evaporator without requiring a costly heat conduction member. The purpose is to.

[0006]

According to the present invention, in order to solve the above-mentioned problems, an airtight chamber in which a temperature-sensitive refrigerant is sealed, and a base end side of which is communicated with the airtight chamber, the refrigerant temperature at the outlet of the evaporator is reduced. A temperature sensing tube for sensing, a diaphragm forming a part of the airtight chamber, and a valve body for changing a flow path area of a throttle section through which the high-pressure refrigerant sent to the evaporator passes by driving the diaphragm. In the expansion valve, the temperature-sensitive tube may be bent at its end so as to have at least one bent portion to increase the length of a temperature-sensitive portion that comes into contact with an outlet pipe of the evaporator. Provided.

According to such an expansion valve, the length of the temperature-sensitive portion that comes into contact with the outlet pipe of the evaporator is lengthened by bending the tip of the temperature-sensitive tube, and the contact with the outlet pipe at the temperature-sensitive portion is increased. The area was increased. As a result, the contact area can be increased by devising the tip shape of the temperature sensing tube itself, so that the heat conducting member interposed between the temperature sensing tube and the outlet pipe of the evaporator in order to increase the contact area. Becomes unnecessary, and the cost can be reduced.

[0008]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a partial sectional view showing the expansion valve according to the first embodiment.

This expansion valve has a high-pressure refrigerant passage 2 drilled from the side toward the center at a substantially central portion of the body 1 in the longitudinal direction, and a lower end portion drilled in the axial direction. It has a low-pressure refrigerant passage 3. At the axial position of the body 1, there is a hole communicating between the high-pressure refrigerant passage 2 and the low-pressure refrigerant passage 3, and the end on the low-pressure refrigerant passage 3 side is a valve seat 4. A spherical valve element 5 is disposed facing the valve seat 4, and the valve element 5 is urged toward the valve seat 4 by a conical spring 6. The proximal end of the conical spring 6 is received by an adjusting screw 7. The adjusting screw 7 is screwed onto the inner wall surface of the low-pressure refrigerant passage 3. By rotating the adjusting screw 7, the urging force on the valve element 5 can be changed to adjust a set value at which the valve element 5 starts to open. it can.

The upper portion of the body 1 is integrally formed with a fixing portion 8 whose outer peripheral portion projects in a cylindrical shape so as to form a part of a temperature sensing chamber. A diaphragm 9 made of a flexible thin metal plate and a housing 10 made of a metal plate are arranged in the fixing portion 8, and the peripheral portion is fixed by caulking the fixing portion 8 to form an airtight chamber. ing. The space between the fixing portion 8 of the caulked portion and the housing 10 is brazed to improve the tightness of the airtight chamber. A temperature sensing tube 1 formed of a capillary tube for sensing a temperature change of the refrigerant flowing through the outlet pipe of the evaporator is provided at a central portion of the housing 10.
1 is welded. In the airtight chamber formed by the housing 10 and the diaphragm 9, the thermosensitive tube 1 is provided.
A gas having the same or similar properties as the refrigerant as the working fluid of the refrigeration cycle is filled in a saturated vapor state. The distal end of the temperature sensing tube 11 is bent to form a temperature sensing portion 12 that comes into contact with the outlet pipe of the evaporator.

A shaft 13 is inserted through an axial position of the body 1 located below the temperature sensing chamber so as to be able to advance and retreat in the axial direction. Through the lower surface of the diaphragm 9. The upper end of the shaft 13 is
Is positioned at the axial position of the body 1.

The body 1 is provided with a communication passage 16 for equalizing the space under the diaphragm 9 of the temperature sensing chamber with the low-pressure refrigerant passage 3. A space below the diaphragm 9 is sealed from the high-pressure refrigerant passage 2 by an O-ring 17 provided on the shaft 13.

In the expansion valve having the above structure, when the refrigerant is supplied to the high-pressure refrigerant passage 2 through the high-pressure refrigerant pipe, the refrigerant passes through the gap formed by the valve seat 4 and the valve element 5. And is sent to the evaporator from the low-pressure refrigerant passage 3 through the low-pressure refrigerant pipe. The refrigerant output from the evaporator is sent to the compressor, and the outlet temperature of the refrigerant at that time is detected by the temperature-sensitive portion 12 of the temperature-sensitive tube 11.

According to the detected temperature, the pressure of the gas sealed in the airtight chamber changes, and the pressure in the airtight chamber rises and falls.
On the other hand, since the low-pressure refrigerant passage 3 communicates with the back side of the airtight chamber through the communication passage 16, the back surface of the diaphragm 9 receives the refrigerant pressure in the low-pressure refrigerant passage 3. The diaphragm 9, the shaft 13, and the valve body 5 are stopped at a position where the pressure of the refrigerant, the pressure in the airtight chamber, and the urging force of the conical spring 6 are balanced, and the amount of the refrigerant sent from the high-pressure refrigerant pipe to the evaporator is determined.

Here, when the outlet temperature of the refrigerant flowing out of the evaporator increases, the pressure in the airtight chamber increases, and the pressure in the diaphragm 9 increases.
Is displaced downward, and the displacement pushes down the valve body 5 via the shaft 13 to increase the valve opening, thereby increasing the flow rate of the refrigerant, and controlling the outlet temperature of the refrigerant exiting the evaporator to decrease. When the outlet temperature of the refrigerant discharged from the evaporator becomes low, the reverse operation is performed to control so as to increase the outlet temperature of the refrigerant discharged from the evaporator.

FIG. 2 is a perspective view showing a state in which the temperature sensing tube of the expansion valve according to the first embodiment is attached to the outlet pipe of the evaporator. The temperature sensing tube 11 of the expansion valve constitutes a temperature sensing portion 12 by bending one end portion thereof. The temperature-sensitive portion 12 is provided on an outer surface of an outlet pipe 18 provided on the outlet side of the evaporator, for example, by a metal band 1.
9 for fastening. As described above, since the temperature-sensitive portion 12 can extend the length in contact with the outlet pipe 18 of the evaporator by bending the end of the temperature-sensitive tube 11 to increase the contact area, the outlet pipe 18 The temperature of the flowing refrigerant can be efficiently transmitted to the temperature-sensitive portion 12.

FIG. 3 is a perspective view showing a state in which the temperature sensing tube of the expansion valve according to the second embodiment is attached to the outlet pipe of the evaporator. According to the second embodiment, the temperature-sensitive portion 12 is formed by bending the distal end portion of the temperature-sensitive tube 11 at two places. Thereby, the length of the temperature sensing tube 11 in the temperature sensing portion 12 becomes longer than in the case of the first embodiment, so that the contact area with the outlet pipe 18 can be further increased.

In the above embodiment, the temperature-sensitive portion 1
2 illustrates the case having 1 or 2 bent portions,
It may have a bent portion larger than that.

[0019]

As described above, according to the present invention, at least one end of the temperature sensing tube is bent so that the length of the temperature sensing portion in contact with the outlet pipe of the evaporator is increased. Thereby, it is possible to increase the contact area of the temperature-sensitive portion that comes into contact with the outlet pipe of the evaporator, and the same effect as in the case where a heat conducting member is interposed between the temperature-sensitive pipe and the outlet pipe of the evaporator. Since it can be obtained and no heat conducting member is required, the cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a partial sectional view showing an expansion valve according to a first embodiment.

FIG. 2 is a perspective view showing a state in which a temperature sensing tube of the expansion valve according to the first embodiment is attached to an outlet pipe of an evaporator.

FIG. 3 is a perspective view showing a state in which a temperature sensing tube of an expansion valve according to a second embodiment is attached to an outlet pipe of an evaporator.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Body 2 High-pressure refrigerant passage 3 Low-pressure refrigerant passage 4 Valve seat 5 Valve body 6 Conical spring 7 Adjust screw 8 Fixing part 9 Diaphragm 10 Housing 11 Temperature sensing tube 12 Temperature sensing part 13 Shaft 14 Disk 15 Holder 16 Communication path 17 O-ring 18 Outlet piping 19 band

Continued on the front page (72) Inventor Takeshi Kaneko 1211-4 Nukuda-cho, Hachioji-shi, Tokyo Inside TDK Corporation

Claims (2)

[Claims] An airtight chamber filled with a temperature-sensitive refrigerant, a temperature-sensitive tube having a base end communicated with the airtight chamber to sense a refrigerant temperature at an outlet of an evaporator, and a part of the airtight chamber. An expansion valve having a diaphragm that changes a flow path area of a throttle portion through which high-pressure refrigerant sent to the evaporator passes by driving the diaphragm, wherein the temperature-sensitive tube has at least one bent portion. An expansion valve characterized in that the length of the temperature-sensitive portion in contact with the outlet pipe of the evaporator is lengthened by bending the tip so as to have the following. 2. A hermetic chamber filled with a refrigerant for temperature sensing, a thermosensitive tube having a base end communicated with the hermetic chamber to sense a refrigerant temperature at an outlet of an evaporator, and forming a part of the hermetic chamber. And a valve body for changing a flow path area of a throttle portion through which the high-pressure refrigerant sent to the evaporator passes by driving the diaphragm. A mounting structure for an expansion valve, wherein a temperature-sensitive portion formed by bending at least one bent portion is bound to an outlet pipe of the evaporator.