JPS6117788A - Expansion valve - Google Patents

Abstract

PURPOSE:To simplify the structure of an expansion valve by adding a function as a heating unit to a valve driving element. CONSTITUTION:When an electric current does not flow through a valve driving element 14, the valve driving element 14 is bent to be convex as shown by a two-dot chain line because there is no self-heat generation and it is in the state of low-temperature, so that a spindle 15 is pushed upward to increase the open area of an orifice 9. When an electric current is applied to the valve driving element 14, the valve driving element generates heat by itself so that the valve driving element 14 itself comes to a high temperature, and is deformed to be flat by a shape memory effect of the valve driving element 14. Thus, the spindle 15 is pushed downward to reduce the open area of the orifice 9.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an expansion valve that changes a flow path area by controlling the energization of a plate-shaped valve driving element formed of a shape memory alloy. .

Conventional Structure and Problems Conventionally, an expansion valve constructed using a shape memory alloy as shown in FIG. 1 has been proposed. In this conventional example, the valve driving element 1 is formed of a shape memory alloy, and is curved into a convex shape at the center due to the elasticity of the bias spring 2. When the valve driving element 1 is heated above a certain temperature, the valve driving element 1 is made of a shape memory alloy. becomes flat. This flattening causes the spindle 3 to deflect in the direction of closing the orifice against the elasticity of the bias spring 2, thereby closing the orifice 4. In other words, the opening of the expansion valve is fully controlled by energizing the heater 5 that is in contact with the valve drive element 1. However, in the conventional example, the heater 5 is added to give thermal deformation to the valve drive element 1. However, the structure is complicated and the operation is delayed.

Technical Problem of the Invention The present invention has been made in view of the drawbacks of the above-mentioned conventional examples.
Rather than installing a heater that adds all of the thermal energy to the valve drive element made of a shape memory alloy, the heater is added by adding a function as a heating element to the valve drive element and directly energizing the valve drive element. The purpose of this invention is to provide an inexpensive expansion valve with a simple structure and quick response.

Technical Means of the Invention In order to achieve the above object, the present invention provides a main body having a fluid inlet and a fluid outlet, and a spindle connected to a plate-shaped valve driving element made of a shape memory alloy; An orifice whose opening area changes according to the displacement of the spindle is provided, and a control circuit is provided to control the energization of the valve drive element.

Effect of the Invention With this configuration, the valve drive lever made of a shape memory alloy is directly energized, and the valve drive element is deformed by utilizing the self-heating of the valve drive element and the shape memory effect at this time. The orifice opening area is controlled by interlocking spindles.

Example of a pharyngeal structure Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 2 is a schematic diagram of an expansion valve showing one embodiment of the present invention.

In FIG. 2, 6 is a main body having a fluid lower, a fluid outlet 8, and an orifice 9, and a lower lid 10 and an upper i11 are joined to seal the main body 6. On the inside of the main body of the upper lid 11 is a retainer made of conductive material.

A pedestal 13 is provided, and a plate-shaped valve driving element 14 made of a shape memory alloy is joined to the supporting pedestal 13. Furthermore, the valve driving element 14 has a spindle 15 for changing the opening area of the orifice 9, and a valve driving element 14 for changing the opening area of the orifice 9. A bias spring 16 for applying a counterforce to the drive element 14 is connected and mounted in free contact with the main body. A terminal block 12 is provided on the outside of the main body of the top cover 11, and the valve drive element 1 is mounted on the terminal block 12.
A control circuit 17 for controlling energization to 4 is connected thereto.

Note that the terminal block 12, the support stand 13, and the valve drive element 14 are electrically connected and insulated from other parts.

Here, the plate-shaped valve drive element 14 is made of a shape memory alloy that exhibits unidirectional operation, and when the valve drive element 14 becomes hot, it assumes a shape as shown by the solid line in FIG. 2, that is, a flat shape. As such, amnesia has been pre-processed.

This shape change occurs in a certain temperature range, and the shape change temperature range can be adjusted by the composition of the shape memory alloy or heat treatment.

In the above configuration, the operation of the spindle 15 shown in FIG. 2 to change the total opening area of the orifice 9 will be explained.

First, a state in which the control circuit 17 does not energize the valve drive element 14 will be described. At this time, since no current is flowing through the valve drive element 14, there is no self-heating and the valve drive element 14 is at a low temperature, so the valve drive element 14 is moved as shown by the two-dot chain line in FIG. At the same time, the spindle 15 connected to the valve drive element 14 is pushed upward, and the opening area of the orifice 9 is increased.

Next, when the control circuit 17 energizes the valve drive element 14, the electric resistance of the shape memory alloy causes self-heating and the valve drive element 14 itself becomes high temperature.
Due to the shape memory effect, the bias spring 16 overcomes the drag force and deforms into a flat shape, and at the same time, the spindle 15 is pushed down and the opening area of the orifice 9 is reduced.

In this way, the present expansion valve deforms the valve drive element 14 by utilizing self-heating due to energization of the plate-shaped valve drive element 14 made of a shape memory alloy and the shape memory effect at this time. In both cases, the opening area of the orifice 9 is changed by displacement of the spindle 15 connected to the valve drive element 14.

Effects of the Example In this expansion valve, the function of a heating element is added to the valve drive element 14, and the heater 4 can be removed by direct energization, so the structure can be simplified. . Further, by directly energizing the valve driving element 14, there is less heat loss than when heating is indirectly performed from the surroundings, and therefore the response is better than heating with a heater having the same amount of heat.

In this example, the shape memory alloy forming the valve driving element is unidirectional, but the same effect can be obtained even if the shape memory alloy exhibits bidirectional operation, and in this case, counterforce is applied. There is no need for a bias spring for this purpose.

In addition, in this example, the valve driving element formed of a shape memory alloy is subjected to memory treatment so that it becomes flat when heated to high temperatures, but conversely, by performing memory treatment so that it becomes convex. , it is possible to reverse the change in the orifice opening area due to energization of the valve drive element to that in this embodiment.

Effects of the Invention As is clear from the above embodiments, the expansion valve of the present invention has a main body having a fluid inlet, a flow, and an outlet connected to a plate-shaped valve driving element formed of a shape memory alloy. A spindle and an orifice whose opening area changes depending on the displacement of the spindle are provided, and a control circuit is provided to control energization to the valve drive element, and the valve drive element has a function as a heat generating element. As a result, the heater can be completely removed, the structure can be simplified, and the valve driving element can be electrically energized directly, resulting in good responsiveness and other excellent effects.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing a conventional expansion valve, and FIG. 2 is a sectional view of an expansion valve showing an embodiment of the present invention. 6...Body, 7...Fluid inlet, 8...
...Fluid outlet, 9... Orifice, 14...
・Valve drive element, 15... spindle, 17...
control circuit.

Claims (1)

[Claims] A main body having a fluid inlet and a fluid outlet is provided with a spindle connected to a plate-shaped valve driving element made of a shape memory alloy, and an orifice whose opening area changes according to displacement of the spindle. An expansion valve equipped with a control circuit that controls energization of the element.