JPH049948B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a control valve that controls the opening of a valve hole by utilizing the displacement of a driving body made of a shape memory alloy due to temperature changes.

Shape memory alloys utilize the phenomenon that occurs when the low-temperature phase generated by thermoelastic martensitic transformation is deformed and then reversely transformed into the high-temperature phase by heating. It changes to an austenite structure at higher temperatures, and changes to a martensitic structure at lower temperatures. When this shape memory alloy is cooled from the high temperature side, the austenitic structure transforms to the martensitic structure, and it has superelasticity.On the other hand, when it is heated from the low temperature side, the martensitic structure transforms to the austenite structure, and the forming process It returns to the memorized shape. Nickel-titanium, copper-aluminum-nickel, copper-aluminum, etc. are known as alloys that exhibit such a shape memory effect, and the opening and closing of the valve hole is caused by the displacement of these shape memory alloys due to temperature changes. What has been done is known from Japanese Utility Model Application Publication No. 56-56969 and Japanese Patent Application Laid-Open No. 57-25572.

However, in the operating means for opening and closing the valve shown in Japanese Utility Model Application Publication No. 56-56969, the opening/closing means is formed of a shape memory alloy and is dependent on the temperature of the control fluid flowing down the valve body. According to such a structure, Temperature changes in the control fluid are essential, and it is unsuitable for applications in which such temperature changes cannot be obtained, and has the disadvantage of being unsuitable for wide control valve applications.

Furthermore, Japanese Patent Application Laid-Open No. 57-25572 discloses a structure in which a valve drive element made of a shape memory alloy is heated directly with a heater to control the opening and closing of the valve hole. Since it is a heating process, a large amount of electric power is required, and heaters with small diameter wires are generally used. There was a risk of wire breakage, and the opening/closing control function of the control valve was poor.

Furthermore, in a structure in which the heater is directly wound around the valve driving element, it is necessary to provide an insulating coating to insulate the heater from those elements, which makes efficient heating difficult. Ta.

The control valve using the shape memory alloy of the present invention was created in view of the above-mentioned disadvantages, and it directly controls the driving body that drives the valve body without heating or cooling it with the environmental temperature of the control fluid, etc. Furthermore, since it is electrically heated, it can be widely used as a control valve, and requires less electricity to open and close compared to a control valve that opens and closes the valve by directly heating the driver with a heater. The object of the present invention is to obtain a control valve that can generate a large amount of heat, heat a driving member directly from the heating element, and has excellent heating characteristics and good valve opening/closing controllability.

EMBODIMENT OF THE INVENTION Hereinafter, one embodiment of a control valve using a shape memory alloy according to the present invention will be described with reference to the drawings.

1 has a flow path 2 passing through it, and is divided into a primary flow path 2A and a secondary flow path 2B by a valve seat 3 provided in the middle of the flow path 2. This is a valve body provided with an opening recess 2C that opens toward the front. A mounting stay 4 is disposed on the opening recess 2C of the valve body 1, and the mounting stay 4 includes a flat plate-shaped closing plate portion 4A that closes the opening recess 2C, and a closing plate portion 4A.
A reduced diameter portion 4B that continuously opens upward from approximately the center thereof, and an enlarged diameter portion 4C that expands from the upper end of the reduced diameter portion and continuously opens upward.

Reference numeral 5 denotes a valve stem that is slidably guided and held within the reduced diameter portion 4B of the earlier mounting stay, and the lower end of the valve stem 5 in the opening recess 2C of the valve body 1 has a valve seat 3 for opening and closing. A flange portion 5B having a larger diameter than the valve rod 5 is formed at the upper end of the valve rod 5 within the enlarged diameter portion 4C of the mounting stay 4.

A spiral coil 6 made of a conductive material such as copper is disposed in the upper opening of the enlarged diameter portion 4C of the mounting stay 4 to close the upper opening, and both ends of the coil 6 are connected to a power source 7. The outer periphery thereof is filled and fixed with epoxy resin or the like.

Further, a cylindrical heating element 8 made of a magnetic material such as iron is arranged on the lower surface of the coil 6 facing into the enlarged diameter section 4C, and the lower surface of this heating element 8 faces into the enlarged diameter section 4C. become.

Thus, the upper opening of the mounting stay 4 is closed by the heating element 8 and the coil 6.

Further, a coil spring as a driving body 9 made of a shape memory alloy is disposed between the upper surface of the flange 5B of the valve stem 5 and the lower surface facing the enlarged diameter portion 4C of the heating element 8, and the upper end of this driving body 9 is locked to the lower surface of the heating element 8, and the lower end is locked to the upper surface of the flange 5B. Further, a spring 10 that elastically urges the valve stem 5 upward in the figure is compressed between the lower surface of the flange portion 5B and the stepped portion A formed by the reduced diameter portion 4B and the enlarged diameter portion 4C. will be established.

A driving body 9 made of the shape memory alloy
As for the coil spring, when the temperature decreases at the martensitic transformation start point (M point),
The elongation deformation of the driving body 9 starts, and this deformation stops when it reaches the martensitic transformation end point (point M), and on the other hand, the shape starts to be restored at the reverse transformation start point (point A) due to the temperature rise. Shrinkage deformation begins and ends at the reverse transformation end point (point A), returning to the set shape.

Next, we will discuss its operation.

When the coil 6 is not energized, no heat is applied to the drive body 9 made of a shape memory alloy, so the drive body 9 reaches the reverse transformation temperature (point A).
Therefore, the driving body 9 is held in an extended state.At this time, by making the stretching force of the driving body 9 larger than the spring force of the spring 10, the valve including the valve body 5A is The rod 5 is pressed downward and the valve seat 3 is held closed by the valve body 5A. Therefore, the flow path 2 is maintained in a blocked state.

Next, when the coil 6 is energized, radial lines of magnetic force are generated from the coil 6, and these lines of magnetic force pass through the heating element 8 disposed near the coil 6. When the magnetic lines of force pass through the heating element 8, Joule heat is generated within the heating element 8 due to eddy currents induced by the magnetic lines of force, causing the temperature of the heating element 8 itself to rise rapidly. According to this temperature rise of the heating element 8, the driving element 9 disposed close to the heating element 8 also receives heat from the heating element 8 and experiences a temperature rise, and the temperature of the driving element 9 undergoes reverse transformation. Starting point (point As)
As it rises further, the driving body 9 starts to contract,
The temperature further increases and reaches the end point of reverse transformation (Af point), at which point the contraction is completed. When the driver 9 contracts, the valve stem 5 including the valve body 5A is displaced upward by the spring 10, opening the valve seat 3 and keeping the flow path 2 open.

As described above, according to the control valve of the present invention, the control valve includes: a flow path 2 passing through the inside thereof, and a valve seat 3 provided in the flow path 2;
An opening recess 2 that is divided into a primary flow path 2A and a secondary flow path 2B and is recessed facing the valve seat 3.
and a reduced diameter portion 4B that opens and extends toward one side from the closing plate portion that closes the opening recess 2C of the valve body 1.
and an enlarged diameter portion 4C that opens toward one side from the end of the reduced diameter portion 4B; A heating element 8 made of a magnetic material that is located within the enlarged diameter section 4C of the mounting stay 4 and has one end facing the coil 6 and the other end facing into the enlarged diameter section 4C; A reduced diameter of the mounting stay 4. A valve rod 5 that is slidably guided by the portion 4B, has a valve body 5A for opening and closing the valve seat 3 at one end located within the opening recessed portion 2, and has a collar portion 5B at the other end located within the enlarged diameter portion 4C; A drive made of a shape memory alloy, which is located inside the enlarged diameter section 4C of the mounting stay 4, and whose one end is engaged with the flange section 5B of the valve stem 5 and whose other end is engaged with the heating element 8 facing the enlarged diameter section 4C. The body 9 is located within the enlarged diameter portion 4C of the mounting stay 4, one end is locked to the flange portion 5B of the valve stem 5, and the other end is locked to the reduced diameter portion 4B to compress the drive body 9. Since it is constructed by the arranged springs 10 and ;, the following effects are particularly achieved.

Since the spiral coil serving as the dielectric heating means and the heating element made of a magnetic material placed opposite to the coil can be housed in the mounting stay placed on the valve body, the heating means for the drive body made of a shape memory alloy can be used. The advantage of these control valves is that they can be placed compactly in the valve body, and the external shape of these control valves themselves is similar to that of conventional solenoid valves (the mounting stay is formed by a reduced diameter part and an enlarged diameter part). It can be made compatible with solenoid valves, and the degree of freedom in its installation is not hindered in any way. That is, the solenoid valve can be easily replaced.

Since the driver does not come into direct contact with the coil, there is no need to provide a special insulating coating. The heating element will serve as an insulating film.

Since the heat generated in the heating element is directly transferred to the driver, the heating characteristics of the driver can be improved, and a control valve with excellent thermal responsiveness can be provided.

[Brief explanation of drawings]

The figure is a longitudinal sectional view showing an embodiment of the control valve that will be explained herein. 1...Valve body, 3...Valve seat, 4...Mounting stay, 4B...Reduced diameter part, 4C...Enlarged diameter part, 5...
... Valve stem, 5A... Valve body, 5B... Flange, 6... Coil, 7... Heating element, 9... Drive body, 10... Spring.

Claims (1)

[Claims] 1. A flow path 2 passes through the inside, and is divided into a primary flow path 2A and a secondary flow path 2B by a valve seat 3 provided in the flow path 2, and faces the valve seat 3. A valve body 1 consisting of an opening recess 2C recessed in the valve body 1; and a reduced diameter portion 4B opening and extending toward one side from the closing plate portion that closes the opening recess 2C of the valve body 1.
and an enlarged diameter portion 4C that opens toward one side from the end of the reduced diameter portion 4B; A heating element 8 made of a magnetic material that is located within the enlarged diameter section 4C of the mounting stay 4 and has one end facing the coil 6 and the other end facing into the enlarged diameter section 4C; A reduced diameter of the mounting stay 4. A valve rod 5 that is slidably guided by the portion 4B, has a valve body 5A for opening and closing the valve seat 3 at one end located within the opening recessed portion 2C, and has a collar portion 5B at the other end located within the enlarged diameter portion 4C; A drive made of a shape memory alloy, which is located inside the enlarged diameter section 4C of the mounting stay 4, and whose one end is engaged with the flange section 5B of the valve stem 5 and whose other end is engaged with the heating element 8 facing the enlarged diameter section 4C. The body 9 is located within the enlarged diameter portion 4C of the mounting stay 4, and is arranged so that one end is locked to the collar 5B of the valve stem 5 and the other end is locked to the reduced diameter portion 4B to compress the driver 9. A control valve consisting of a spring 10 and;