JP2007315529A - Compact valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compact valve capable of sealing an orifice by utilizing contraction of a wire formed by shape memory alloy to prolong service life of the wire. <P>SOLUTION: This compact valve 1 is provided with a fixed structure 2 having the orifice 25, a movable structural body 3 being freely movable for the fixed structure 2, the wire 4 formed by the shape memory alloy, and a bias elastic body 5 for giving bias tensile stress to the wire 4, which is engaged with the bias elastic body 5 and is held by a first electrode 6 and a second electrode 7. A protruding part 33 of the movable structural body 3 is engaged with the bias elastic body 5. When carrying electric current to the wire 4 through the first electrode 6 and the second electrode 7, the wire 4 is heated and contracted, and the bias elastic body 5 is deformed to move the movable structural body 3 and seal the orifice 25. The stress acting on the wire 4 while the orifice 25 is sealed is reduced by deformation of the bias elastic body 5. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a small valve for controlling various fluids such as gas and liquid using a shape memory alloy.

Conventionally, as a small valve for performing this kind of fluid adjustment, for example, as disclosed in Patent Document 1, a movable structure is inserted into a cylindrical fixed structure having an orifice, and a wire made of a shape memory alloy is used. A small valve is known in which an orifice is sealed by engaging a movable structure, energizing and contracting the wire, and pulling the movable structure against the orifice by pulling it with the wire.
JP-A-11-153234

  By the way, the shape memory alloy usually has a contracted shape that has been previously memorized when the temperature is higher than a certain temperature, and has a property of recovering to its original shape when the temperature returns to the low temperature of the initial temperature. However, when an excessive stress (overload) is applied to the shape memory alloy, the shape memory alloy does not recover to the original shape, and the reproducibility of the recovered shape deteriorates.

  In the conventional small valve described above, in order to maintain the hermeticity of the orifice, the electric heating of the wire made of the shape memory alloy is continued even after the movable structure is pressed against the orifice, so that the orifice of the movable structure It is necessary to continue pressing on the. However, in such a state where the pressing of the movable structure to the orifice is continued, the movable structure cannot move any more, so that the wire cannot be contracted despite trying to contract, and excessive Stress (overload) is applied. As a result, the wire made of the shape memory alloy has a possibility that the reproducibility of the recovery shape is deteriorated and the life is shortened.

  The present invention has been made to solve the above-described problems, and is a compact valve in which an orifice is sealed by moving a movable structure using contraction of a wire made of a shape memory alloy. An object of the present invention is to provide a small valve capable of extending the life of a wire made of a memory alloy.

  In order to achieve the above object, a first aspect of the present invention provides a small valve including a cylindrical fixed structure having an orifice and a movable structure that is inserted in the fixed structure and movably seals the orifice. A wire made of a shape memory alloy held by the first electrode and the second electrode for energization, and a bias elastic body for applying a tensile tensile stress to the wire to relieve stress when the wire contracts The bias elastic body and the wire are engaged with each other, and the movable structure is provided so as to be movable by deformation of the bias elastic body. The wire is energized through the first electrode and the second electrode. Then, by heating the wire and contracting the shape memory alloy to deform the bias elastic body, the movable structure is moved to seal the orifice.

  According to a second aspect of the present invention, in the small valve according to the first aspect, a sealing elastic body is provided for pressing the movable structure so as to seal the orifice.

  According to a third aspect of the present invention, in the small valve according to the first or second aspect, one end of the movable structure is engaged with the fixed structure so as to restrict the movement of the movable structure to the side opposite to the orifice. It has a stop part to stop.

  According to a fourth aspect of the present invention, in the small valve according to any one of the first to third aspects, the bias elastic body and the wire are engaged at two positions.

  According to a fifth aspect of the present invention, in the small valve according to any one of the first to fourth aspects, the fixed structure is formed by joining two pieces to be divided into one piece. A movable structure, a wire, and a bias elastic body are disposed, and then the other piece is joined to one piece.

  According to the invention of claim 1, since the stress acting on the wire is reduced when the wire is in a high temperature state and the movable structure seals the orifice, the life of the wire can be extended.

  According to the invention of claim 2, the operation when the movable structure seals the orifice becomes smooth.

  According to the invention of claim 3, since the stress acting on the wire is reduced when the wire is in a low temperature state and the movable structure releases the sealing of the orifice, the life of the wire can be extended. .

  According to the fourth aspect of the present invention, it is possible to reduce the load applied to the place where the wire is engaged with the bias elastic body, thereby extending the life of the wire.

  According to invention of Claim 5, a small valve can be assembled easily and productivity improves.

Hereinafter, a small valve according to an embodiment of the present invention will be described with reference to the drawings.
<First Embodiment>
First, the first embodiment will be described. 1A, 1B, 1C, and 1D show the configuration of a small valve according to the first embodiment. The small valve 1 controls various fluids such as gas and liquid, and includes a fixed structure 2, a movable structure 3 movably provided with respect to the fixed structure 2, and a movable structure 3 movable. A wire 4 and a bias elastic body 5, and a first electrode 6 and a second electrode 7 for energization.

  The fixed structure 2 includes an end wall portion 21, a peripheral wall portion 22 that continues from the end wall portion 21, and overhang portions 23 and 24 that protrude from the peripheral wall portion 22. It has a cylindrical shape with an opening (on the opposite side to the end wall portion 21), and an orifice 25 that is a small-diameter hole for allowing various fluids such as gas and liquid to flow therethrough is formed in the end wall portion 21. . The fixed structure 2 is made of a nonconductive material such as resin. The first electrode 6 is fixed to the overhang portion 23, and the second electrode 7 is fixed to the overhang portion 24.

  The movable structure 3 is moved to seal and release the orifice 25 of the fixed structure 2, and includes a shaft portion 31 that extends substantially straight, and a head provided at one end of the shaft portion 31. 32 and a projecting portion 33 projecting on the outer peripheral surface of the shaft portion 31, and the shaft portion 31 is movably inserted in a space surrounded by the peripheral wall portion 22 of the fixed structure 2. The diameter of the head portion 32 is formed larger than the diameter of the shaft portion 31. The movable structure 3 is made of a nonconductive material such as resin.

  The wire 4 is made of a shape memory alloy, and both ends thereof are held by the first electrode 6 and the second electrode 7 respectively, and the substantially intermediate portion is related to the bias elastic body 5 so as to be bent at the substantially intermediate portion. Are combined. The shape memory alloy that forms the wire 4 is a material that has a property of contracting when the temperature increases and elongating when the temperature decreases (for example, a Ti—Ni shape memory alloy). Accordingly, when the wire 4 is energized through the first electrode 6 and the second electrode 7, the wire 4 is heated and tends to contract in a high temperature state. When the energization to the wire 4 is stopped, the wire 4 is cooled and is in a low temperature state. Try to stretch back to (normal temperature).

  The bias elastic body 5 is formed of a spiral spring, and is movable between the peripheral wall portion 22 of the fixed structure 2 and the shaft portion 31 of the movable structure 3 and movable with the end wall portion 21 of the fixed structure 2. It is provided between the head 3 of the structure 3 and is inscribed in the peripheral wall 22 of the fixed structure 2. In addition, the bias elastic body 5 is engaged with the wire 4 at a location near the head 22 of the movable structure 3, and the tensile stress of the wire 4 causes the end wall portion 21 of the fixed structure 2 and the wire 4 to be connected. It is in a compressed state. In other words, the bias elastic body 5 gives a bias tensile stress that relaxes the stress when the wire 4 contracts to the wire 4 by the elastic restoring force of the bias elastic body 5.

  The bias elastic body 5 thus provided is held in a state where the tensile stress of the wire 4 and the elastic restoring force of the bias elastic body 5 are balanced. Therefore, the bias elastic body 5 is compressed and deformed when the force that causes the wire 4 to contract due to the high temperature state (when the tensile stress of the wire 4 increases), the wire 4 returns to the normal temperature state and tries to expand. When a force is generated (when the tensile stress of the wire 4 is reduced), it is deformed by extension.

  The movable structure 3 is movable by such a deformation of the bias elastic body 5. That is, when the bias elastic body 5 is compressed and deformed, the movable structure 3 moves in a direction approaching the orifice 25 by pushing the protrusion 33 by the bias elastic body 5, and when the bias elastic body 5 extends and deforms, When the head 32 is pushed by the elastic body 5, the elastic body 5 moves in a direction away from the orifice 25.

  Next, the operation of the small valve 1 having the above configuration will be described. First, when the wire 4 is in a normal temperature state, the shaft portion 31 of the movable structure 3 is separated from the end wall portion 21 of the fixed structure 2, and thus the orifice 25 is not sealed. (See FIG. 1 (a)).

  When the wire 4 is energized through the first electrode 6 and the second electrode 7, the wire 4 is heated to a high temperature state, and a force for contracting the wire 4 is generated. The bias elastic body 5 is compressed and deformed while contracting. When the bias elastic body 5 is compressed and deformed, the projecting portion 33 of the movable structure 3 is pushed by the bias elastic body 5 so that the movable structure 3 moves in a direction approaching the orifice 25, and the shaft portion of the movable structure 3 is moved. 31 is pressed against the end wall portion 21 of the fixed structure 2 so that the orifice 25 is sealed (see FIG. 1D).

  When the orifice 25 is sealed in this way, the movable structure 3 cannot move any more, but the wire 4 can further contract because the bias elastic body 5 can be further compressed and deformed. Is possible. Therefore, after the orifice 25 is sealed, if the energization of the wire 4 is continued in order to maintain the sealed state of the orifice 25, the wire 4 further contracts due to further compression deformation of the bias elastic body 5. This can reduce the stress acting on the wire 4.

  Further, when the energization to the wire 4 is stopped, the wire 4 is cooled and returned to the normal temperature state, and a force to extend the wire 4 is generated. As a result, the wire 4 expands and the bias elastic body 5 extends. Deform. When the bias elastic body 5 is extended and deformed, the head 32 of the movable structure 3 is pushed by the bias elastic body 5 so that the movable structure 3 moves away from the orifice 25, and the shaft portion of the movable structure 3 is moved. 31 is separated from the end wall portion 21 of the fixed structure 2, and the sealing of the orifice 25 is released (see FIG. 1A).

  Thus, according to the small valve 1 of the present embodiment, by energizing the wire 4 through the first electrode 6 and the second electrode 7, the wire 4 contracts and the bias elastic body 5 is compressed and deformed. Thereby, the movable structure 3 is moved and the orifice 25 is sealed. After the orifice 25 is sealed, the wire 4 can be further contracted by further deformation of the bias elastic body 5. Therefore, when the orifice 25 is sealed, the stress acting on the wire 4 is reduced by the deformation of the bias elastic body 5, and no excessive stress (overload) is applied to the wire 4, thereby The life of the wire 4 can be extended.

  In the above-described embodiment, a part of the movable structure 3 is bonded to a part of the bias elastic body 5 without providing the protruding portion 33 on the movable structure 3, so that the bias elastic body 5 is deformed. The movable structure 3 may be movable. In addition, the bias elastic body 5 may be configured to move the movable structure 3 and seal the orifice 25 by expanding and deforming when the wire 4 contracts.

<Second Embodiment>
Next, a second embodiment will be described. FIGS. 2A and 2B show the configuration of a small valve according to the second embodiment. The small valve 1 of this embodiment includes a sealing elastic body 8 in addition to the configuration of the first embodiment.

  In the present embodiment, the fixed structure 2 includes a rear end wall portion 26 and a rear peripheral wall in addition to the end wall portion 21, the peripheral wall portion 22, the overhang portions 23 and 24, and the orifice 25 similar to those in the first embodiment. Part 27 and rear projecting parts 28, 29. The interior is hollow, and an opening is formed between projecting part 23 and rear projecting part 28, and between projecting part 24 and rear projecting part 29. It has a cylindrical shape. Similarly to the first embodiment, the fixed structure 2 is made of a non-conductive material such as resin. The first electrode 6 is fixed to the overhang portion 23, and the overhang portion 24 is fixed to the overhang portion 24. The second electrode 7 is fixed.

  The sealing elastic body 8 is formed of a spiral spring, is inserted into the fixed structure 2, and is interposed between the rear end wall portion 26 of the fixed structure 2 and the head 32 of the movable structure 3. It is provided in a compressed state and is inscribed in the rear peripheral wall portion 27 of the fixed structure 2. That is, the sealing elastic body 8 presses the movable structure 3 so as to seal the orifice 25 by the elastic restoring force of the sealing elastic body 5. Other configurations in the present embodiment are the same as those in the first embodiment.

  In the small valve 1 of the present embodiment, the movable structure 3 is held in a state where the tensile stress of the wire 4, the elastic restoring force of the bias elastic body 5, and the elastic restoring force of the sealing elastic body 8 are balanced. . When the wire 4 is in a normal temperature state (low temperature state), the movable structure 3 is held at a position away from the end wall portion 21 of the fixed structure 2, and the orifice 25 is not sealed. (See FIG. 2 (a)).

  When the wire 4 is energized through the first electrode 6 and the second electrode 7, the bias elastic body 5 is compressed and deformed in the same manner as in the first embodiment because the wire 4 is in a high temperature state and contracts. Accordingly, the movable elastic body 3 is moved to the orifice 25 by the force of the bias elastic body 5 pushing the protrusion 33 of the movable structural body 3 and the force of the sealing elastic body 8 pushing the head 32 of the movable structural body 3. It moves in the approaching direction, and the shaft portion 31 of the movable structure 3 is pressed against the end wall portion 21 of the fixed structure 2 so that the orifice 25 is sealed (see FIG. 2B).

  When the energization of the wire 4 is stopped, the bias elastic body 5 is extended and deformed in the same manner as in the first embodiment because the wire 4 returns to the normal temperature state and expands, whereby the movable structure 3 is sealed. The elastic member 8 is moved in a direction away from the orifice 25 while compressing and deforming, the shaft portion 31 of the movable structure 3 is separated from the end wall portion 21 of the fixed structure 2, and the sealing of the orifice 25 is released. It will be in a state (refer to Drawing 2 (a)).

  Thus, according to the small valve 1 of the present embodiment, the movable structure 3 is pushed by the sealing elastic body 8 in addition to being pushed by the bias elastic body 5, so as to approach the orifice 25. Move to seal the orifice 25. Therefore, according to the small valve 1 of the present embodiment, the operation of the movable structure 3 when the orifice 25 is sealed becomes smooth in addition to the same operations and effects as the first embodiment.

  In the above embodiment, the sealing elastic body 8 is inserted into the fixed structure 2 and compressed between the rear end wall portion 26 of the fixed structure 2 and the head 32 of the movable structure 3. The structure is not limited to that provided in the state, and any structure may be used as long as the movable structure 3 is pressed toward the orifice 25, and any structure may be provided.

<Third Embodiment>
Next, a third embodiment will be described. FIG. 3 shows a configuration of a small valve according to the third embodiment. In the small valve 1 of the present embodiment, the configuration of the fixed structure 2 is different from the configuration of the second embodiment.

  In the present embodiment, the fixed structure 2 includes a stop portion 9 that restricts the movable structure 3 from moving to a side opposite to the orifice 25 from a predetermined position. The stop portion 9 is formed of a step formed in the rear peripheral wall portion 27 of the fixed structure 2, and the movable structure 3 is locked by locking the head portion 32 of the movable structure 3 (that is, one end of the movable structure 32). The body 3 is restricted from moving further to the opposite side of the orifice 25. Other configurations in the present embodiment are the same as those in the second embodiment.

  In the small valve 1 of the present embodiment, when the wire 4 is in a normal temperature state (low temperature state), the movable structure 3 is held in a state of being pressed against the stop portion 9 by the elastic restoring force of the bias elastic body 5. Yes. At this time, the movable structure 3 is held at a position away from the end wall portion 21 of the fixed structure 2, and the orifice 25 is not sealed (see FIG. 3). When the wire 4 is energized through the first electrode 6 and the second electrode 7, the orifice 25 is sealed as in the second embodiment, and when the energization to the wire 4 is stopped. As in the second embodiment, the sealing of the orifice 25 is released.

  According to the small valve 1 of the present embodiment, when the wire 4 is in a normal temperature state and the sealing of the orifice 25 is released, the movable structure 3 is locked by the stop portion 9 and is further opposite to the orifice 25. Since the bias elastic body 5 cannot be moved to the side, further extension deformation of the bias elastic body 5 is suppressed, whereby the load that the wire 4 receives from the bias elastic body 5 is reduced, and the stress acting on the wire 4 is reduced. Therefore, according to the small valve 1 of the present embodiment, in addition to the same operations and effects as those of the second embodiment, when the wire 4 is in a normal temperature state and the orifice 25 is released from sealing, the wire Excessive stress (overload) is not applied to 4, thereby extending the life of the wire 4.

  In the above embodiment, the stop portion 9 is not limited to a step formed on the rear peripheral wall portion 27 of the fixed structure 2 or a portion that locks the head portion 32 of the movable structure 3, Any structure may be used as long as the body 3 is restricted from moving from the predetermined position to the opposite side of the orifice 25.

<Fourth Embodiment>
Next, a fourth embodiment will be described. 4A, 4B, and 4C show the configuration of a small valve according to the fourth embodiment. The small valve 1 of the present embodiment differs from the configuration of the third embodiment in the engagement structure between the wire 4 and the bias elastic body 5.

  In this embodiment, the bias elastic body 5 and the wire 4 are engaged at two locations. The shaft portion 31 of the movable structure 3 has a recess 35 so that the bias elastic body 5 and the wire 4 can be engaged at two locations. Other configurations in the present embodiment are the same as those in the third embodiment.

  According to the small valve 1 of the present embodiment, since the wire 4 is engaged with the bias elastic body 5 at two locations, the load received by the wire 4 from the bias elastic body 5 is distributed at two locations. Therefore, according to the small valve 1 of the present embodiment, in addition to the same operations and effects as the third embodiment, it is possible to reduce the load applied to the place where the wire 4 is engaged with the bias elastic body 5, The life of the wire 4 can be extended.

<Fifth Embodiment>
Next, a fifth embodiment will be described. FIGS. 5A to 5I show a method for assembling a small valve according to the fifth embodiment. In this embodiment, the fixed structure 2 is formed by joining two pieces 2a and 2b to be divided (see FIGS. 5G, 5H, and 5I). Other configurations in the present embodiment are the same as those in the fourth embodiment.

  One piece 2 a of the fixed structure 2 includes one end wall portion 21 of the fixed structure 2, a part of the peripheral wall portion 22, overhang portions 23 and 24, an orifice 25, a rear end wall portion 26, and a rear peripheral wall portion 27. And rear projecting portions 28 and 29, and has an open storage space for storing the movable structure 3, the wire 4, the bias elastic body 5, and the sealing elastic body 8. Yes. The other piece 2b of the fixed structure 2 forms the remaining part of the peripheral wall portion 22 of the fixed structure 2 and the remaining part of the rear peripheral wall portion 27, and has a substantially flat plate shape. . The one piece 2a and the other piece 2b become the fixed structure 2 by joining the other piece 2b to the one piece 2a so as to cover the storage space of the one piece 2a with the other piece 2b.

  The small valve 1 of this embodiment is assembled as follows. First, one piece 2a of the fixed structure 2 is prepared (see FIGS. 5A, 5B, and 5C), and the first electrode 6 and the second electrode 7 are formed on the overhang portions 23 and 24 of the one piece 2a. The movable structure 3, the wire 4, the bias elastic body 5, and the sealing elastic body 8 are disposed in the storage space of one piece 2a (see FIGS. 5D, 5E, and 5F). Next, the other piece 2b is joined to the one piece 2a so as to cover the storage space of the one piece 2a with the other piece 2b (see FIGS. 5G, 5H, and 5I). Thereby, the small valve 1 is completed. According to this embodiment, the small valve 1 can be easily assembled, and productivity is improved.

  In addition, in the said embodiment, the fixed structure 2 has the part which comprises the end wall part 21, the surrounding wall part 22, and the overhang | projection parts 23 and 24, the rear end wall part 26, the rear periphery wall part 27, and the back overhang part. 28 and 29 may be divided into two pieces, or may be divided into two pieces around a line passing through the orifice 25 in parallel with the movable direction of the movable structure 3. It may be.

(A) is sectional drawing when the orifice of the small valve | bulb which concerns on the 1st Embodiment of this invention is not sealed, (b) is the sectional view on the AA line of (a), (c) is (a) BB line sectional drawing of (), (d) is sectional drawing when the orifice is sealed. (A) is sectional drawing when the orifice of the small valve | bulb which concerns on the 2nd Embodiment of this invention is not sealed, (b) is sectional drawing when the orifice is sealed. Sectional drawing when the orifice of the small valve | bulb which concerns on the 3rd Embodiment of this invention is not sealed. (A) is sectional drawing when the orifice of the small valve | bulb which concerns on the 4th Embodiment of this invention is not sealed, (b) is a principal part which shows the engagement structure of the bias elastic body and wire of the orifice The enlarged view and (c) are CC sectional view taken on the line of (b). It is a figure which shows the assembly method of the said small valve, (a) is a top view in the state which has not arrange | positioned components to one piece of a fixed structure, (b) is the side view, (c) is the same cross section (D) is a plan view of a state in which parts are arranged on one piece of a fixed structure, (e) is a side view, (f) is a cross-sectional view, and (g) is one side of the fixed structure. The top view of the state which arrange | positioned components in the piece and joined the other piece, (h) is the side view, (i) is the sectional drawing.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Small valve 2 Fixed structure 2a 1st piece 2b 2nd piece 3 Movable structure 4 Wire 5 Bias elastic body 6 1st electrode 7 2nd electrode 8 Elastic body for sealing 9 Stop part 25 Orifice

Claims (5)

In a small valve comprising a cylindrical fixed structure having an orifice and a movable structure that is inserted into the fixed structure and movably seals the orifice,
A wire made of a shape memory alloy held by the first electrode and the second electrode for energization;
A bias elastic body that imparts a tensile stress of a bias that relaxes the stress when the wire contracts to the wire;
The bias elastic body and a wire are engaged, and the movable structure is provided to be movable by deformation of the bias elastic body,
By energizing the wire through the first electrode and the second electrode, heating the wire to contract the shape memory alloy and deforming the bias elastic body, thereby moving the movable structure and A small valve characterized by sealing an orifice.   The small valve according to claim 1, further comprising a sealing elastic body that presses the movable structure so as to seal the orifice.   2. The stop structure for locking the one end of the movable structure to the fixed structure so as to restrict the movement of the movable structure to the opposite side of the orifice. Item 3. The small valve according to Item 2.   The small valve according to any one of claims 1 to 3, wherein the bias elastic body and the wire are engaged at two positions. The fixed structure is formed by joining two pieces to be divided,
5. The movable structure, the wire, and the bias elastic body are arranged on one piece, and then the other piece is joined to the one piece. The small valve as described in any one.

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