JP2005226573A - Pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To eliminate the necessity of solenoids and armatures, reduce costs by simplifying a structure, reduce the size and remove anxiety for wear by reducing the number of sliding members. <P>SOLUTION: In this pump, four coil spring-shaped actuators 10 to 13 made of shape memory alloy are hung between an electrode 14 mounted on a piston 2 and electrodes 16, 17 mounted on a cover 15. When a drive current is supplied to these actuators 10 to 13, they are contracted so as to have a solid winding posture. At this time, liquid in a pump chamber 9 is flowed out from a check valve 24. Next, when a drive current is supplied to actuators 4 to 7, the actuators 4 to 7 are contracted until they become solid winding. The other actuators 10 to 13 are extended, and fluid in a pump chamber 3 is flowed out from a check valve 21. The pump is constituted so as to repeat these steps. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an improvement in a pump that performs pumping action by changing the volume of a pump chamber by reciprocating movement of a piston.

  In an electromagnetic pump in which the volume of the pump chamber in each cylinder formed in the left and right housings is changed by the armature reciprocated by receiving electromagnetic force from the solenoid, and the two pump chambers are alternately pumped. An electromagnetic pump in which a piston is provided in each pump chamber and left and right pistons are in contact with the armature is known (see, for example, Patent Document 1).

In this electromagnetic pump, the diameters of the left and right pistons are set smaller than the diameter of the armature.
JP 2001-41148 A

  The conventional pump has a structure in which three reciprocating members including the armature and left and right pistons slide left and right in the housing, and two solenoids for applying an electromagnetic force to the armature are also required. It was. Therefore, there is a problem that the structure is complicated and the cost is high. In addition, each of the armature and the left and right pistons requires consideration of sliding wear with the housing, and there is a problem in that there is an adverse effect on cost. Furthermore, in order to reduce the stirring resistance when the piston reciprocates left and right, it is necessary to provide the armature with a communication passage or a communication groove that communicates the left and right chambers of the sliding space. There was a problem of becoming.

  In addition, there is a problem in that the driving unit, which is an electromagnetic force generating part such as a solenoid or an armature, becomes large and the pump weight increases.

  Therefore, the present invention is simple in structure, requires only a small number of members with less consideration for sliding wear, and does not require an armature itself provided with a communication passage or a communication groove communicating with the left and right sliding spaces. An object is to provide a small and lightweight pump.

  The present invention is a pump in which the volume of the left and right pump chambers of the piston is changed by the reciprocating motion of the piston, and the two pump chambers alternately perform the pumping action. The main feature is that an actuator is provided and a drive current is allowed to flow through each actuator at intervals. Either the left or right side of the actuator made of shape memory alloy may be replaced with a tension spring. In this case, a drive current is intermittently supplied to the remaining actuator made of shape memory alloy.

  In order to achieve the above object, the invention according to claim 1 is a pump in which the volume of the left and right pump chambers of the piston is changed by the reciprocating motion of the piston, and the two pump chambers are alternately pumped. The pump is characterized in that actuators made of a shape memory alloy are arranged on the left and right sides of the pistons to act on the pistons, and a drive current is alternately supplied to each actuator at intervals.

  According to a second aspect of the present invention, there is provided a pump in which the volume of the left and right pump chambers of the piston is changed by the reciprocating movement of the piston, and the two pump chambers are alternately pumped. A pump is characterized in that a tension spring is disposed on the other side of the actuator and acts on each piston, and a drive current is intermittently supplied to the actuator.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, the actuator made of a shape memory alloy disposed on one of the pistons is a coil spring.

  According to a fourth aspect of the present invention, in the third aspect of the present invention, a plurality of actuators are provided on one of the pistons, and a shape restoring force is applied thereto.

  According to a fifth aspect of the invention, in the fourth aspect of the invention, a plurality of actuators arranged on one side of the piston are electrically connected in parallel.

  A sixth aspect of the present invention is the pump according to any one of the first to fifth aspects, wherein the fluid is a liquid.

  Since the present invention is configured as described above, the structure is simple and maintenance is easy. Therefore, the cost can be reduced. Moreover, since a solenoid or an armature is not required, a small pump can be realized. In addition, since the reciprocating member is a single piston, it is not necessary to provide a total of three reciprocating members between the armature and the two pistons as a countermeasure for coaxial displacement as in the prior art, and the piston length is also output. It is advantageous in terms of cost because it can be shortened because it has no effect.

In the invention of claim 3, the operation amount of the actuator can be increased.
In the invention of claim 4, the acting force applied to the piston of the actuator can be increased.

  In the invention of claim 5, electrical connection of a plurality of actuators in the pump chamber is facilitated.

  In the invention of claim 6, since the temperature rise of the shape memory alloy is suppressed by the fluid, there is an advantage that the response can be improved and the cycle period (t1 + t2 or T) can be reduced.

  Next, the best mode for carrying out the present invention will be described based on the embodiments shown in the drawings.

  FIG. 1A is a longitudinal sectional view, FIG. 1B is a side view, and FIG. 2 is a cross-sectional view taken along line A- in FIG. A sectional view and FIG. 3 are BB sectional views in FIG. 4 shows a longitudinal sectional view of a mode different from FIG. 1A of the first embodiment, FIG. 1A shows a mode in which the piston moves to the left end, and FIG. 4 shows a mode in which the piston moves to the right end. Show. Each figure is an enlarged view from the actual state as described later.

  In these drawings, an electrically insulating synthetic resin piston 2 is slidably disposed in a cylindrical cylinder 1 in the left-right direction in the figure. In FIG. 1 (a), the piston 2 is at the left end position, and in FIG. It is in the rightmost position. In the left pump chamber 3, four coil spring actuators 4, 5, 6, 7 made of a shape memory alloy are disposed, each right end is mechanically connected to the electrode 8, and also electrically It is connected. The electrode 8 is provided with recesses into which the right ends of the four actuators 4, 5, 6, and 7 are fitted at equal intervals (every 90 degrees) on the circumference centered on the axis XX of the cylinder or piston 2. The right ends of the coil spring-like actuators 4, 5, 6 and 7 are fitted into the respective recesses, and are mechanically firmly connected and fixed. Therefore, the right ends of these four actuators 4 to 7 are electrically connected to each other via the electrode 8. The electrode 8 is generally disc-shaped as a whole and is fixed to the left side surface of the piston 2 as shown in FIG.

  The pump chamber 9 on the right side of the piston 2 is provided with four coil spring actuators 10, 11, 12, 13 made of a shape memory alloy, each left end of which is mechanically connected to an electrode 14, and It is also electrically connected. The electrode 14 is provided with recesses into which the left ends of the four actuators 10, 11, 12, and 13 are fitted at equal intervals (every 90 degrees) on the circumference centered on the axis XX of the cylinder 1 or piston 2. The left ends of the coil spring-like actuators 10, 11, 12, and 13 are fitted into these recesses, and are mechanically firmly connected and fixed. Therefore, the left ends of these four actuators 10 to 13 are electrically connected to each other via the electrode 14. The electrode 14 is generally disc-shaped as a whole, and is fixed to the right side surface of the piston 2 as shown in FIG.

  In FIG. 1A, two electrodes 16 and 17 are inserted into a lid 15 made of an electrically insulating material fixed to the right end of the cylinder 1. One electrode 16 has a coil spring-like actuator. The right ends of 10 and 13 and the right ends of the coil spring-like actuators 11 and 12 are mechanically firmly connected and fixed to the other electrode 17 and are also electrically connected.

  Further, two electrodes 19 and 20 are inserted into a lid 18 made of an electrical connection material fixed to the left end of the cylinder 1, and the left end of each of the coil spring-like actuators 4 and 7 is inserted into one electrode 19. However, the left ends of the coil spring-like actuators 5 and 6 are mechanically firmly connected and fixed to the other electrode 20 and are electrically connected.

  By the way, the actuators 4 to 7 and 10 to 13 are each formed by winding a shape memory alloy wire in a coil spring shape, and are commercially available under the name of Biometal Helix made by Toki Corporation. Biometal is a registered trademark of the company. This biometal helix is hereinafter abbreviated as BMX.

  BMX used in the examples is made of Ti—Ni-based shape memory alloy as a raw material and has anisotropy in the twisting direction of the wire. The wire diameter d is 0.2 mm and the coil outer diameter D is 0. .85 mm and the coil diameter D / d wire diameter ratio is 4.25, which is a very small and fine coil spring. This BMX is in the form of tightly wound coils when shipped from the manufacturer Toki Corporation. This is stretched and deformed at room temperature (room temperature). 1 to 4, the actuators 4 to 7 and 10 to 13 have a wire diameter d of 0.2 mm and a coil outer diameter D of 0.85 mm enlarged about 6.5 times. In the drawing, the outer diameter of the cylinder 1 is also enlarged, and the actual dimension is as small as 5.7 mm.

  In the embodiment, when the BMX is purchased from the manufacturer, it is a coil spring-like coil that is closely wound, and the length in the closely wound state is the length in the left-right direction of the actuators 4 to 7 in FIG. Equivalent to. This is used by being extended at room temperature to a size slightly larger than the length in the left-right direction of the actuators 10 to 13 shown in FIG. That is, it is stretched to about twice the length when closely wound.

  By the way, BMX begins to shrink little by little as the temperature is raised, and when it exceeds 70 ° C., it contracts rapidly and almost shrinks at 80 ° C. That is, it returns to the memorized tightly wound shape. At the time of cooling, it begins to relax-extend from about 75 degrees and finishes almost extending at 60 ° C to 70 ° C. The so-called temperature hysteresis is 10 ° C. or less. Compared to general shape memory alloys, the hysteresis of temperature is very small, and it is said that a larger strain can be taken out effectively. BMX has a relatively large electric resistance, and the resistance value is close to that of a nichrome wire. Therefore, since it can be utilized as an actuator of an electric / thermal drive system in which a current is passed to generate heat and move like a nichrome wire, this is utilized in the present invention. In the embodiment, the fluid is a pump that handles fuel, water, oil, and the like.

  In order to pass a current through the actuators 4 to 7, a voltage is applied to the terminal portions 19 a and 20 a of the electrodes 19 and 20. Further, in order to pass a current through the actuators 10 to 13, a voltage is applied to the terminal portions 16 a and 17 a of the electrodes 16 and 17.

  Each actuator, that is, each BMX has a standard heating current (standard driving current) of 300 to 400 mA, a generated force during heating (high temperature) of 40 to 50 gf, and a motion displacement (length change) of 200%. Accordingly, in FIGS. 1 to 4, when a drive current is passed through the actuators 4 to 7 in the left pump chamber 3, the actuators 4 to 7 contract between 40 to 50 gf as shown in FIG. Is moved to the illustrated position. At this time, the actuators 10 to 13 of the right pump chamber 9 are pulled by the piston 2 and extend as shown in the figure. Little force is required to extend the low temperature actuators 10-13.

  When a driving current is supplied to the actuators 10 to 13 of the right pump chamber 9, the actuators 10 to 13 contract with a force of 40 to 50 gf, and the piston 2 is moved to the position shown in FIG. At this time, the actuators 4 to 7 of the left pump chamber 3 are pulled by the piston 2 and extend as shown in FIG.

  When the piston 2 moves to the left, the volume of the pump chamber 3 decreases, and fluid flows out from the pump chamber 3 through the check valve 21. At this time, the check valve 22 is closed. At this time, the volume of the right pump chamber 9 increases, and the fluid flows from the check valve 23 into the pump chamber 9.

  Next, when the piston 2 moves to the right, the volume of the pump chamber 9 decreases and the fluid flows out from the check valve 24. Further, the fluid flows into the pump chamber 3 from the check valve 22.

  In order to move the pump continuously, a driving current is intermittently supplied to the actuator by the electric circuit shown in FIG. FIG. 4A is an electric circuit, and FIG. 4B is a time chart showing voltage waveforms at a, b, c, and d of the circuit of FIG. The output a of the rectangular wave oscillator 25 is applied to the inputs of the AND gates 26 and 27 and also input to the ½ divider circuit 28. The output b of the 1/2 divider circuit 28 is applied to the input of the AND gate 26 and the input of the AND gate 27 through the inverter 29. The output c of the AND gate 26 causes a drive current to flow from the power source + E to the actuators 4 to 6 via the transistor Tr1. The output d of the AND gate 27 causes a drive current to flow to the actuators 10 to 13 via the transistor Tr2. In addition, each actuator 4-7 and 10-13 are described as shown to Fig.5 (a) in an electrical circuit diagram.

  The driving current flows through the actuators 4 to 7 of the left pump chamber 3 at a time interval T only during the period t1 in which the output c of the AND gate 26 is between the H levels in FIGS. . In addition, the actuators 10 to 13 in the right pump chamber 9 have a driving current that passes the time interval T only during a period t1 in which the output d of the AND gate 27 is between the H levels in FIGS. Flowing. A time interval t2 is provided between the time when the output c shown in FIG. 5B becomes the L level and the time when the output d becomes the H level.

  That is, after the drive current of the actuators 4 to 7 in the left pump chamber 3 stops, there is an interval of time t2 until the drive current of the actuators 10 to 13 in the right pump chamber 9 starts to flow. At the same time, after the drive current of the actuators 10 to 13 in the right pump chamber is cut off, there is an interval of time t2 until the drive current starts to flow in the actuators 4 to 7 in the left pump chamber. This is because even if the current of the actuator in one pump chamber is cut off, the temperature of the actuator does not decrease immediately, so that a drive current is supplied to the actuator in the other pump chamber after a time t2 until the temperature decreases. It is for doing so.

  In order to mechanically connect and fix the right ends of the actuators 4 to 7 to the electrode 8, they are connected and fixed by welding, soldering or caulking. A similar method can be used to connect and fix the left ends of the actuators 10 to 13 to the electrode 14. In addition, when the left ends of the actuators 4 to 7 are connected and fixed to the electrodes 19 and 20, or the right ends of the actuators 10 to 13 are connected to and fixed to the electrodes 16 and 17, the right ends of the actuators 4 to 7 and the electrodes 8 are used. The same construction method can be used as connecting and fixing.

  Instead of the actuators 10 to 13 in one of the pump chambers in the first embodiment, for example, the right pump chamber 9, a pump is used by using four tension coil springs made of a normal spring material without using a shape memory alloy. Can be configured.

  In this case, each coil spring is smaller than one shape recovery force (50 to 60 gf) of the actuators 4 to 7 in the left pump chamber (although these are actuators of the same size and shape), so that it can be deformed at a low temperature. Set a force (bias force) greater than the required force. In the second embodiment in which BMX is used for the actuators 4 to 7, the bias force of the tension coil spring used in place of the actuators 10 to 13 is set to about half of the shape recovery force of the actuators 4 to 7.

  The electric circuit of Example 2 is shown in FIG. In this case, the output a of the rectangular wave oscillator 25 is input to the AND gate 26, and the output c of the AND gate 26 is the same as the output a of the oscillator 25 as shown in FIG.

  Accordingly, the drive current flows from the power source + E to the BMX4 to 7 as the actuators for the time t1 every period T / 2. The period t2 is used as a cooling period for the actuator BMX.

1 shows Embodiment 1 of the present invention, in which (a) is a longitudinal sectional view and (b) is a side view. FIG. AA sectional drawing of Fig.1 (a). BB sectional drawing of Fig.1 (a). The longitudinal cross-sectional view at the time of the different aspect of the Example of FIG. The electric circuit diagram used for Example 1 of FIGS. The electric circuit diagram of Example 2 of this invention.

Explanation of symbols

1 Cylinder 2 Piston 3, 9 Pump chamber 4, 5, 6, 7 Actuator made of shape memory alloy 10, 11, 12, 13 Actuator made of shape memory alloy

Claims (6)

  In the pump that changes the volume of the pump chamber on the left and right of the piston by the reciprocating motion of the piston and alternately pumps the two pump chambers, actuators made of shape memory alloy are arranged on the left and right of the piston, respectively. Then, the pump is made to act on the piston, and a drive current is alternately passed through each actuator at intervals.   In a pump in which the volume of the left and right pump chambers of the piston is changed by the reciprocating movement of the piston to cause the two pump chambers to alternately perform the pumping action, an actuator made of a shape memory alloy is applied to one of the pistons, and a tension spring to the other The pump is characterized in that each is acted on a piston, and a drive current is intermittently supplied to the actuator.   The pump according to claim 1 or 2, wherein the actuator made of a shape memory alloy disposed on one of the pistons is in a coil spring shape.   4. The pump according to claim 3, wherein a plurality of actuators are provided on one of the pistons, and their shape recovery force is applied.   5. The pump according to claim 4, wherein a plurality of actuators disposed on one of the pistons are electrically connected in parallel.   The pump according to any one of claims 1 to 5, wherein the fluid is a liquid.

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