JP2006281178A - Syringe pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a syringe pump capable of discharging a minute amount of liquid highly precisely at a high speed. <P>SOLUTION: The syringe pump 1 is provided with a syringe 2, a piston 3 and a moving device of the piston 3. The moving device is provided with a driving rod 70 which is allowed to advance and retreat by expansion and contraction of a piezoelectric element 72, a guide rod parallel to the driving rod 70, a unidirectional clutch member 8 and a declutching means 10. When the driving rod 70 moves in a first direction, a ball 86 of the unidirectional clutch member 8 is brought into pressurized contact with the driving rod 70 and a ring member 82 to lock the unidirectional clutch member 8, and the unidirectional clutch member 8, a pipe 9 and the piston 3 are also moved to deliver liquid. When the driving rod 70 moves in a second direction, the unidirectional clutch member 8 is locked for a guide rod by the ball 86 of the unidirectional clutch member 8 and the movement of the unidirectional clutch member 8 is inhibited. Owing to the expansion and contraction of a piezoelectric element 72, the piston 3 can be moved accurately by a minute quantity in the delivery direction and a minute amount of liquid can be discharged highly precisely at a high speed. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a syringe pump including a syringe (injection cylinder) and a piston (pushing element), and more particularly to a syringe pump capable of discharging a small amount of liquid with high accuracy and at high speed.

The syringe pump has been used to hold the syringe in a replaceable manner, set a syringe filled with a liquid in advance to the pump, and push out and discharge the liquid. Since this syringe pump can also seal the liquid in the syringe until the syringe is set in the pump, it can improve hygiene, and it can also be used for hazardous substances, highly viscous liquids, defoamed liquids, etc. There are advantages such as easy handling.
For this reason, syringe pumps have been widely used for medical purposes, and can be used for various types of liquids such as adhesives, silver pastes, solder pastes, greases, chemicals, and liquid crystals. Widely used in parts manufacturing and assembly lines.

As a syringe pump used in the above applications, an air type pump that supplies pressurized air to the inside of the syringe and pushes out the liquid inside the syringe is generally used (see Patent Document 1).
Since the pneumatic syringe pump controls the pressure and pressurization time of the pressurized air supplied through the tube into the syringe and pushes out the liquid, the syringe part can be made lightweight. For this reason, in a manufacturing / assembly line or the like, a syringe pump is attached to a robot arm and the liquid is discharged while moving the pump relative to the workpiece.

JP 2002-361144 A

However, the pneumatic syringe pump has the following problems.
In other words, regarding the setting and accuracy of the discharge amount, there are many factors that affect the discharge amount, such as air pressure, space size, time, needle (nozzle) conditions, and liquid viscosity. It was difficult. For this reason, in order to improve the accuracy of the discharge amount, it is necessary to repeat the feedback control by measuring the actually discharged liquid amount, such as photographing the discharged liquid portion and performing image processing, and the control is complicated. there were.
In addition, regarding the operating speed, a rise time is required from when a signal instructing discharge is input until the liquid actually starts to be discharged. It could not be shortened to about 10 msec or less.

  An object of the present invention is to provide a syringe pump capable of discharging a small amount of liquid with high accuracy and at high speed.

  A syringe pump according to the present invention includes a syringe filled with a liquid, a piston that is disposed so as to be able to advance and retreat in the syringe and that can push out and discharge the liquid filled in the syringe, and a moving device that moves the piston. The moving device includes a piezoelectric element, a drive rod that moves forward and backward in the movement axis direction of the piston as the piezoelectric element expands and contracts, a guide rod disposed in parallel to the drive rod, the drive rod, and When the drive rod is disposed across the guide rod and moves in the first direction, the drive rod is locked with respect to the drive rod and moves together with the drive rod to push the piston and discharge the liquid. A one-way clutch member that is locked with respect to the guide rod and stops without moving with the drive rod when moved in the second direction opposite to the direction; Characterized in that it comprises a clutch release means which freely movable relative to the one-way clutch releasing to each rod a locked state for the drive rod and the guide rod members.

In the present invention, the liquid in the syringe is discharged by moving the piston through the drive rod and the one-way clutch member using the piezoelectric element. Can be discharged.
That is, since the one-way clutch member that moves together with the drive rod only when the drive rod moves forward and backward by expansion and contraction of the piezoelectric element and the drive rod moves to the piston side, the piston can be moved by the displacement amount of the piezoelectric element. . Since the positioning accuracy of the piston due to the displacement of the piezoelectric element can be made higher than that when using air pressure, a very small amount of liquid can be discharged with high accuracy according to the present invention.
In addition, since the piezoelectric element has a response speed as fast as about 1/1000 compared to the pneumatic type, the liquid can be discharged at a high speed. Furthermore, since the amount of movement of the piston due to one expansion / contraction of the piezoelectric element is small, a very small amount of liquid can be discharged, and since the piezoelectric element can be driven at high speed, the liquid discharged per unit time, for example, for 1 second The amount can be the same as that of the pneumatic type, and it can cope with various discharge conditions.
And since the syringe pump of the present invention uses the one-way clutch member that moves linearly along the drive rod and the piezoelectric element to drive the piston, it is as small as a pneumatic syringe pump, The weight can be reduced, and the syringe pump can be easily reduced in size compared to the case where a servo motor and a ball screw drive mechanism are employed. Therefore, when using the syringe pump of the present invention for discharging adhesives and various pastes in the production line of various products, it can be attached to the robot arm and moved at high speed and high acceleration. The tact time can be shortened, and it can contribute to productivity improvement.

In addition, since the piezoelectric element generates a larger force than when driven by a pneumatic method, even if the nozzle is thinned and the resistance is increased, the liquid can be ejected and discharged. For this reason, for example, even 0.1 microliters of water can be blown cleanly, and a stable operation can be realized.
In addition, the displacement amount of the piezoelectric element can be easily adjusted by the voltage value applied to the piezoelectric element. Therefore, by adjusting the stroke amount of the piston by the voltage value, the discharge amount for each time can be adjusted even during the driving operation. It can be adjusted automatically. For this reason, in the step of attaching a plurality of electronic components on the substrate, in order to apply a different amount of adhesive for each electronic component attachment location, the amount of liquid discharged on the substrate may be changed, In a production line where products are mixed and sent, even when the liquid discharge amount is changed for each product, a syringe pump that can be easily handled and can be provided is provided.

  In the present invention, the one-way clutch member includes a first clutch means that is switched between a locked state and an unlocked state with respect to the drive rod, and a second clutch that is switched between a locked state and an unlocked state with respect to the guide rod. The first clutch means is in a locked state with respect to the drive rod when the drive rod moves in the first direction and is moved together with the drive rod, and the drive rod is moved in the second direction. And the second clutch means is unlocked with respect to the guide rod when the one-way clutch member moves in the first direction together with the drive rod, and When the drive rod moves in the second direction, the drive rod is locked with respect to the guide rod. It is preferable to prohibit the movement of the one-way clutch member.

  According to the present invention, the one-way clutch member can move in the same direction when the drive rod moves in the first direction by the first clutch means, and the drive rod moves in the second direction by the second clutch means. The one-way clutch member can be prohibited from moving in the same direction. Therefore, the one-way clutch member can be moved only in the first direction, that is, the piston can be moved only in the liquid discharge direction, and it is possible to reliably prevent the liquid from flowing back into the syringe by returning the piston.

  Here, the drive rod and the guide rod are formed of round bars having a circular cross section, and the first clutch means and the second clutch means are respectively larger in diameter than the drive rod and the guide rod, and the drive rod and the guide rod A guide ring having a through-hole through which the rod is inserted; an inner peripheral surface of the through-hole of the guide ring; and an outer peripheral surface of the drive rod and the guide rod; A plurality of balls arranged at intervals along the circumferential direction; and a biasing means for biasing the balls toward the first direction side, the inner circumference of the through hole of the guide ring The surface includes a tapered surface that decreases in diameter toward the first direction, and the diameter of the ball includes a drive rod, a guide rod, and a tapered surface. Of dimension between, greater than the minimum dimension, it is preferably set smaller than the maximum dimension.

  According to such a configuration, when the drive rod is moved in the first direction by the piezoelectric element, the ball that is in contact with the drive rod is moved by the drive rod to the side where the distance between the taper surface and the drive rod is narrow, and the taper surface. And it is fixed in pressure contact between the drive rods. Accordingly, the one-way clutch member moves in the first direction together with the drive rod, and the liquid is discharged by the piston. At this time, the one-way clutch member also moves in the first direction with respect to the guide rod. However, the guide rod moves in the second direction relative to the ball in contact with the guide rod, and the ball tapers. Since the distance between the surface and the guide rod is moved wider, the one-way clutch member is unlocked with respect to the guide rod, and the movement of the one-way clutch member is not hindered.

  On the other hand, when the drive rod is moved in the second direction by the piezoelectric element, the ball in contact with the drive rod is moved by the drive rod to the side where the distance between the tapered surface and the drive rod is wider, and the lock is released. At this time, even if the one-way clutch member tries to move in the second direction with respect to the guide rod, the guide rod moves in the first direction relative to the ball abutting on the guide rod, and the ball has a tapered surface and a guide. Since the distance between the rods is reduced, the one-way clutch member is locked with respect to the guide rod, the one-way clutch member does not move in the second direction, and liquid backflow is reliably prevented. The

  As described above, when the drive rod is advanced and retracted by the piezoelectric element, the one-way clutch member is automatically switched to the locked state or the unlocked state, so there is no need to provide a special control mechanism for controlling on / off of the clutch. The configuration can be simplified and the cost can be reduced. Moreover, since the 1st clutch means locked with respect to a drive rod and the 2nd clutch means locked with respect to a guide rod are the same structures, components can be shared and cost can be reduced.

  In the present invention, the drive rod and the guide rod are made of round bars having a circular cross section, and the first clutch means and the second clutch means have a diameter larger than that of the drive rod and the guide rod, respectively, and pass therethrough. A guide ring having a hole, a ball holder disposed in a through-hole of the guide ring and having the drive rod and the guide rod inserted through a central shaft portion, and a space along the circumferential direction of the ball holder And a plurality of balls arranged one by one in the plurality of through-holes formed, and an inner peripheral surface of the through-hole of the guide ring has a diameter toward the first direction. The diameter of the ball is larger than the minimum dimension among the dimensions between the drive rod and guide rod and the tapered surface, The through hole of the ball cage is set smaller than the large dimension, and the balls arranged in the through hole are in contact with the inner peripheral surfaces of the rods and the guide ring. The diameter of the through hole is made larger than that of the ball, and the axial direction of the ball holder passes through the center point of the through hole on the first direction side with respect to the center point of each through hole. On the other hand, a magnet capable of attracting the ball is provided for each through hole at an oblique position offset in the circumferential direction, and the ball holder may be provided so as to be rotatable about each rod as a rotation center. .

  Even in such a configuration, when the drive rod is moved in the first direction by the piezoelectric element, the ball that is in contact with the drive rod is moved by the drive rod in a direction where the distance between the taper surface and the drive rod is narrow. It is fixed by pressure between the drive rods. Accordingly, the one-way clutch member moves in the first direction together with the drive rod, and the liquid is discharged by the piston. At this time, the one-way clutch member also moves in the first direction with respect to the guide rod. However, the guide rod moves in the second direction relative to the ball in contact with the guide rod, and the ball tapers. Since the distance between the surface and the guide rod is moved wider, the one-way clutch member is unlocked with respect to the guide rod, and the movement of the one-way clutch member is not hindered. Further, since the ball is attracted by the magnet, when the drive rod moves in the first direction, the ball is pressed between the tapered surface and the drive rod at a position offset in the circumferential direction from the center position of the through hole. Fixed.

  On the other hand, when the drive rod is moved in the second direction by the piezoelectric element, the ball in contact with the drive rod is moved by the drive rod to the side where the distance between the tapered surface and the drive rod is wider, and the lock is released. At this time, even if the one-way clutch member tries to move in the second direction with respect to the guide rod, the guide rod moves in the first direction relative to the ball abutting on the guide rod, and the ball has a tapered surface and a guide. Since the distance between the rods is reduced, the one-way clutch member is locked with respect to the guide rod, the one-way clutch member does not move in the second direction, and liquid backflow is reliably prevented. The

  As described above, also in the present invention, when the drive rod is advanced or retracted by the piezoelectric element, the one-way clutch member is automatically switched to the locked state or the unlocked state, so a special control mechanism for controlling on / off of the clutch is provided. There is no need to provide it, and the configuration can be simplified and the cost can be reduced. Moreover, since the 1st clutch means locked with respect to a drive rod and the 2nd clutch means locked with respect to a guide rod are the same structures, components can be shared and cost can be reduced.

Here, it is preferable that the clutch release means includes a ball moving member capable of moving the ball in the second direction by an external operation.
According to such a structure, if the said ball | bowl is moved to a 2nd direction, a ball | bowl can be moved to the one where the space | interval between a taper surface and each rod is wide, and a locked state can be cancelled | released easily.
Further, by using a ball cage with a built-in magnet, when the ball is pressed and fixed between the tapered surface and the drive rod at a position offset in the circumferential direction from the center position of the through hole, If the ball cage is moved in the second direction, the inner circumferential surface of the through hole of the ball cage comes into contact with the ball and can move in the second direction while rotating the ball along the inner circumferential surface. The distance between the tapered surface and each rod can be easily moved to the wider side, and the friction between the ball and the tapered surface and each rod can be changed from static friction to dynamic friction, reducing the force required for unlocking and releasing operability. Can be improved.

The one-way clutch member includes a drive pipe having a drive rod inserted therein and one end fixed to the piston, and the piston and the syringe are provided on an axis of the drive rod and the drive pipe. It may be what you have.
A syringe containing a liquid such as silver paste or liquid crystal used in a production line has a piston cup disposed in a syringe filled with the liquid, and is formed on the discharge port of the syringe and on the opposite side of the discharge port. It is often prepared in a state where each opening of a syringe into which a piston cup is inserted is closed with a cap. According to the configuration of the present invention, the piston moved by the drive pipe is inserted into, for example, the piston cup in the syringe, and the drive pipe fixed to the piston is moved to the inside of the syringe, thereby completing the discharge of the liquid in the syringe. The piston can be moved reliably until

Further, the piston and the syringe may be provided in parallel with the drive rod, and the one-way clutch member may have an abutting portion capable of abutting on an end portion of the piston.
In many cases, a syringe containing a medical solution used in a medical field is a plunger type piston having a long axial direction. In such a case, if the syringe and the piston are arranged on the axis of the drive rod, the entire length of the syringe pump becomes long and handling becomes difficult. On the other hand, in this invention, since the drive rod, piston, and syringe are arrange | positioned in parallel, the full length of a syringe pump can be shortened and handling property can be improved.

  The piezoelectric element has one end surface in the expansion / contraction direction in contact with the element case through a spherical member, and the other end surface is in contact with an element receiving member attached to the end of the drive rod through the spherical member. Each spherical member is in contact with the piezoelectric element so that the end surface of the piezoelectric element can be in close contact with each other, the contact surface with the element case and the element receiving member is a spherical surface, and the element receiving member is The element receiving member and the drive rod move in the first direction against the urging force of the urging means when the piezo-electric element is extended by being urged toward the second direction and in close contact with the spherical member of the piezoelectric element. When the piezoelectric element contracts, it is preferable that the element receiving member and the drive rod move in the second direction by the urging force of the urging means.

  Since spherical members are provided at both ends of the piezoelectric element, and the spherical surface of this spherical member is in contact with each element case and element receiving member, it is possible to prevent the piezoelectric element from being applied with a bias load, and the piezoelectric element is damaged by the bias load. Can be prevented.

Here, the syringe pump of the present invention includes a sensor that detects the displacement amount of the piezoelectric element or the displacement amount of the drive rod, and a control unit that controls a voltage value applied to the piezoelectric element in accordance with the output of the sensor. It is preferable.
Since there is a hysteresis between the applied voltage and the displacement amount of the piezoelectric element, it is difficult to adjust the displacement amount by feedforward control, but as in the present invention, the displacement amount of the piezoelectric element or the like is detected, If feedback control based on the displacement amount is performed, the displacement amount can be controlled with high accuracy.
For the measurement of the displacement amount, for example, a strain gauge or a capacitance type position sensor may be used.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 shows a syringe pump 1 of the present embodiment, FIG. 2 shows a cross-sectional view along the line AA in FIG. 1, and FIG. 3 shows a line along the line BB in FIG. A cross-sectional view is shown.
The syringe pump 1 includes a syringe 2, a piston 3, a syringe table 4, a guide rod 5, a syringe lid member 6, a drive unit 7, and a one-way clutch member 8.

  As shown in FIG. 2, the syringe 2 has a discharge port 21 to which a nozzle or the like is attached on the lower end side, and the piston 3 is fitted on the upper end side. A cap is attached to the discharge port 21 so that the liquid in the syringe 2 can be sealed together with the piston 3.

  The piston 3 includes a piston body 31 and a piston cup 32. The piston main body 31 is made of, for example, plastic, and a sealing material 33 such as an O-ring that seals a gap with the inner peripheral surface of the syringe 2 is attached to the outer periphery. A recess 34 is formed on the upper end surface of the piston body 31, and a sealing material 35 is also attached to the inner peripheral surface of the recess 34. Further, a through-hole is formed in the central axis portion of the piston body 31, and when the piston body 31 is inserted into the piston cup 32, the air in the piston cup 32 is discharged to place the piston body 31 in the piston cup 32. It is configured so that it can be inserted smoothly.

The piston cup 32 is a cover material that prevents the filled liquid from directly contacting and affecting the piston body 31 and is made of a fluororesin having excellent liquid resistance and chemical resistance.
The piston 3 is not limited to the piston main body 31 and the piston cup 32, and may be, for example, a rubber integral. If it is rubber-made piston 3, even if it does not provide the sealing material 33 separately, a liquid leak can be prevented. Thus, what is necessary is just to set the structure and material of piston 3 according to the kind of liquid to discharge.

  Such a syringe 2 is normally provided in a state in which a liquid is filled in advance, a piston cup 32 is inserted, and the opening on the opposite side of the discharge port 21 and the discharge port 21 is sealed with a cap. Therefore, the user attaches the syringe 2 filled with the liquid to the syringe base 4, and after discharging the liquid, removes the syringe 2 from the syringe base 4 and replaces it with a new syringe 2.

The syringe base 4 has a screw hole 41 for attaching to a robot arm or the like. Further, a discharge port 21 of the syringe 2 and a recess 42 that holds a tapered portion continuous to the discharge port 21 are formed.
The two guide rods 5 are screwed to the syringe table 4. The syringe lid member 6 is disposed so as to straddle the two guide rods 5 and is provided so as to be movable along the guide rods 5. Each guide rod 5 is provided with a pipe 51 having a predetermined length for restricting the movement of the syringe lid 6 toward the syringe base 4.

Therefore, when the syringe 2 is mounted on the syringe table 4, the syringe lid member 6 is separated from the syringe table 4, the syringe 2 is inserted into the concave portion 42 of the syringe table 4, and then the syringe lid material 6 is attached to the syringe table 4. The syringe 2 is sandwiched between the syringe base 4 and the syringe lid 6 and attached.
In the present embodiment, the syringe lid member 6 is formed with a cylindrical insertion portion 61, and the insertion portion 61 is fitted to the syringe 2.

The drive unit 7 includes a drive rod 70 and a rod advance / retreat mechanism 71 that moves the drive rod 70 forward and backward.
As shown in FIG. 4, the rod advance / retreat mechanism 71 mainly includes a piezoelectric element 72 and a disc spring 73 as an urging means for urging the drive rod 70 toward the piezoelectric element 72 (second direction side). And an element case 74 in which the piezoelectric element 72 is accommodated.

The element case 74 is formed in a substantially box shape, and the guide rods 5 are attached to both ends thereof. That is, one end of the guide rod 5 is fixed to the syringe table 4, the other end is fixed to the element case 74, and the guide rods 5 are arranged in parallel to each other.
The element case 74 is attached with a connector 75 to which wiring from a controller (control means) (not shown) for controlling the driving of the piezoelectric element 72 is connected. A drive signal (voltage) is applied from the connector 75 to the piezoelectric element 72 via a wiring (not shown).

  Here, the piezoelectric element 72 is a ceramic laminated piezoelectric element formed in a rectangular parallelepiped shape. If the longitudinal dimension (vertical dimension in FIG. 2) is about 20 mm, a predetermined drive voltage ( For example, when 100 V) is applied, the longitudinal dimension is displaced by about 11 μm. This displacement amount is mainly proportional to the longitudinal dimension of the piezoelectric element 72. If the longitudinal dimension is approximately 40 mm, the displacement amount is approximately 28 μm.

An opening is formed in the end surface of the element case 74 on the syringe base 4 side, and a cap 741 is attached. A through hole is formed in the cap 741, and the drive rod 70 and an element receiving member 76 fixed to the end of the drive rod 70 are inserted therethrough.
The element receiving member 76 is formed in a substantially cylindrical shape, and a step portion is provided on the outer peripheral surface thereof. The disc spring 73 is interposed between the stepped portion of the element receiving member 76 and the cap 741, and biases the element receiving member 76 and the drive rod 70 toward the piezoelectric element 72 side.

  The piezoelectric element 72 is disposed between the element case 74 and the element receiving member 76. That is, concave portions are formed on the opposing surfaces of the element case 74 and the element receiving member 76, and both end surfaces on the longitudinal direction side of the piezoelectric element 72 are in contact with the bottom surfaces of the concave portions via the resin sheet 77. Yes. The resin sheet 77 is interposed to prevent the ceramic piezoelectric element 72 from directly contacting the metal element case 74 or the element receiving member 76 such as aluminum, and the piezoelectric element 72 and the like are damaged. This is to make it difficult.

  Therefore, when the drive signal is input to the piezoelectric element 72 and the piezoelectric element 72 extends in the longitudinal direction, the element case 74 side does not move, so that the element receiving member 76 and the drive are driven by the displacement against the biasing force of the disc spring 73. The rod 70 is moved in the direction toward the syringe table 4 (downward in FIG. 2). On the other hand, when the piezoelectric element 72 returns to its original length, the element receiving member 76 and the drive rod 70 are also moved away from the syringe base 4 (upward in FIG. 2) by the biasing force of the disc spring 73.

Next, the configuration of the one-way clutch member 8 will be described.
The one-way clutch member 8 includes a clutch base 80. As shown in FIG. 1, the clutch base 80 is formed in a substantially box shape and is spanned between two guide rods 5. Further, an operation projection 80A is provided on the front side thereof.
A through hole is formed in the central portion of the clutch base 80 in the left-right direction in FIG. 1, and the drive rod 70 is inserted into the through hole. In addition, the syringe base 4 side of the through hole is a large-diameter space, and a substantially cylindrical pin guide member 81 and a ring member 82 as a guide ring are inserted therein.

  The pin guide member 81 is formed with a through hole 811 through which the drive rod 70 is inserted in the central shaft portion. The pin guide member 81 is formed around the through hole 811 in parallel with the through hole 811 so that the pin guide member 81 is axially arranged. A plurality of guide holes 812 penetrating therethrough are formed at equal intervals along the circumferential direction.

The ring member 82 is made of a cemented carbide, and a through-hole portion inside thereof has a diameter larger than that of the drive rod 70. Further, on the inner peripheral surface of the through hole, a tapered surface 821 formed so that the diameter becomes smaller toward the syringe base 4 side, that is, the lower side (first direction) in FIG. 4, and the syringe of the tapered surface 821 A circumferential surface 822 that is formed continuously on the base 4 side and is concentric with the outer circumferential surface of the drive rod 70 is formed.
The pin guide member 81 and the ring member 82 are sandwiched and fixed between the pressing member 83 screwed to the clutch base 80 and the clutch base 80.

  For example, about six guide holes 812 of the pin guide member 81 are formed, and a push pin 84 is inserted into each of the guide holes 812. The push pin 84 is biased toward the syringe stand 4 by a spring 85 provided between the clutch stand 80 and the push pin 84. Therefore, the pushing pin 84 and the spring 85 constitute a biasing means that biases the ball 86 in the first direction.

  A ball 86 is disposed between the tapered surface 821 of the ring member 82 and the drive rod 70. The balls 86 are precision balls made of cemented carbide, and are provided at positions corresponding to the respective push pins 84. That is, when six push pins 84 are provided, six balls 86 are provided. A spherical ball holding recess 841 is formed on the end face of the pin 84 so that the ball 86 moves in the circumferential direction so that the interval between the balls 86 does not shift.

  A return ring 87 is disposed between the circumferential surface 822 of the ring member 82 and the drive rod 70. The return ring 87 is slidable along the drive rod 70. When the return ring 87 is moved toward the piezoelectric element 72 by a clutch release means described later, the ball 86 and the push pin 84 are piezoelectrically moved against the urging force of the spring 85. It moves to the element 72 side.

  The relationship between the diameter of the ball 86 and the diameters of the tapered surface 821 and the drive rod 70 is set as follows. That is, the diameter of the ball 86 is larger than the gap dimension between the end portion of the tapered surface 821 on the circumferential surface 822 side and the drive rod 70, and the end portion of the tapered surface 821 on the piezoelectric element 72 side and the drive rod. It is set smaller than the gap dimension between 70.

Further, through holes are also formed at both ends in the left-right direction of the clutch base 80, and the guide rod 5 is inserted into the through holes as shown in FIG. The pin guide member 81, the ring member 82, the pressing member 83, the pressing pin 84, the spring 85, the ball 86, and the return ring 87 are disposed in the through hole. That is, since the configuration in the through hole through which the guide rod 5 is inserted is the same as the through hole through which the drive rod 70 is inserted, the same configuration is denoted by the same reference numeral and description thereof is omitted.
The guide rod 5 and the drive rod 70 with which the ball 86 abuts are made of cemented carbide like the ball 86 and the ring member 82.

  In the one-way clutch member 8, an end portion of a push pipe 9 as a drive pipe is fixed to a pressing member 83 through which the drive rod 70 is inserted, as shown in FIGS. A drive rod 70 is inserted into the push pipe 9. Further, the end of the push pipe 9 is inserted into the recess 34 of the piston 3. A lid 91 is inserted at the end of the push pipe 9 to prevent liquid from entering the pipe 9.

  A clutch release means 10 is provided on the syringe table 4 side of the one-way clutch member 8. Similar to the clutch base 80, the clutch release means 10 includes a clutch pushing member 100 formed of a plate-like member that is bridged between the two guide rods 5. The clutch pushing member 100 is also provided with a projecting projection 100A provided to face the projection 80A.

A through hole through which the drive rod 70 and the guide rod 5 are inserted is formed in the center portion of the clutch pushing member 100 in the left-right direction and both left and right end portions, respectively. Moreover, the recessed part 101 in which each pressing member 83 can be arrange | positioned is formed in each through-hole part, respectively.
One end of a pin 102 is fixed to each recess 101. A plurality of pins 102 are arranged around the drive rod 70 and the guide rod 5. For example, four rods are arranged around the rods 5 and 70 at intervals of 90 degrees in the circumferential direction. The other end of the pin 102 penetrates the pressing member 83 and is in contact with the return ring 87.

  For this reason, as shown in FIG. 6, when the clutch pressing member 100 is brought close to the clutch base 80 by grasping the protrusion 80A and the protrusion 100A, the pin 102 presses the return ring 87 toward the piezoelectric element 72. Then, the ball 86 and the push pin 84 move toward the piezoelectric element 72 against the urging force of the spring 85. Since the ball 86 moves from the locked state in which the tapered surface 821 of the ring member 82 and the drive rod 70 and the guide rod 5 are in pressure contact with each other, the distance between the tapered surface 821 and the drive rod 70 and the guide rod 5 is wider. The locked state is released. That is, the user can release the locked state of the one-way clutch member 8 by bringing the protrusions 80A and 100A closer to each other, and the user can freely move the one-way clutch member 8 and the clutch release means 10 along the guide rod 5 and the drive rod 70. Can move to. Therefore, the ball moving member that can move the ball 86 in the second direction is configured to include the return ring 87, the pin 102, and the clutch pushing member 100.

As shown in FIG. 1, each side surface of the clutch pushing member 100 is provided with a movement restricting plate 103 that is bent in an L shape and can receive a moment applied when the protrusion 80A and the protrusion 100A are gripped. It is attached. That is, the movement restricting plate 103 is extended from the side surface of the clutch pressing member 100 to the side surface side of the clutch base 80 and is bent to the surface side facing the element case 74 of the clutch base 80. The flange bush 104 is attached.
The flange bush 104 is fitted into each guide rod 5. Therefore, the movement of the clutch pushing member 100 toward the syringe base 4, that is, the movement away from the clutch base 80 is restricted to a position where the flange bush 104 abuts the surface of the clutch base 80 on the element case 74 side.

Next, the liquid discharge operation in the syringe pump 1 of the present embodiment will be described.
[Syringe set]
First, as a preliminary preparation, the cap of the syringe 2 filled with the discharge liquid is removed, the piston main body 31 is attached to the piston cup 32, and the syringe 2 is disposed between the syringe base 4 and the syringe lid member 6. Then, the clutch state of the one-way clutch member 8 is released, the pipe 9 is moved to the piston 3 side, and is inserted into the recess 34 of the piston 3.

[Discharge operation]
When a drive signal is input to the piezoelectric element 72 by a controller (not shown), the piezoelectric element 72 is driven to expand and contract in the longitudinal direction, that is, the axial direction of the drive rod 70, and the drive rod 70 repeats advancing and retracting toward the syringe 2 along with this drive.
Here, the ball 86 is biased toward the syringe 2 by the spring 85, and is in contact with the tapered surface 821 and the outer peripheral surface of the drive rod 70. In this state, when the drive rod 70 moves to the syringe 2 side, the ball 86 in contact with the drive rod 70 also tries to move in the same direction, and the ball 86 is pressed so as to bite into the tapered surface 821. For this reason, the one-way clutch member 8 and the pipe 9 move together with the drive rod 70 to the syringe 2 side, and the piston 3 also moves to the discharge port 21 side with this movement. For this reason, the liquid in the syringe 2 is discharged from the discharge port 21 according to the movement amount of the piston 3.

  The one-way clutch member 8 tends to move toward the syringe 2 with respect to the guide rod 5. At this time, since the guide rod 5 is fixed and does not move, the guide rod 5 moves relatively to the element case 74 side with respect to the one-way clutch member 8, and the ball 86 that contacts the guide rod 5. Also, the element 85 moves against the biasing force of the spring 85 in the direction in which the dimension between the taper surface 821 and the outer peripheral surface of the guide rod 5 increases. Accordingly, the one-way clutch member 8 is unlocked with respect to the guide rod 5 and can freely move.

On the other hand, when the piezoelectric element 72 returns to its original length and the drive rod 70 also returns to its original position, the one-way clutch member 8 has a ball 86 on the element case 74 side, that is, a tapered surface. Since the dimension between 821 and the outer peripheral surface of the drive rod 70 increases, the lock is released.
At this time, if the one-way clutch member 8 tries to move toward the element case 74 with respect to the guide rod 5, the guide rod 5 tends to move relatively toward the syringe 2 with respect to the one-way clutch member 8. It will be. For this reason, as in the case where the drive rod 70 moves to the syringe 2 side, the ball 86 tries to move in the narrow direction of the tapered surface 821 and the outer peripheral surface of the guide rod 5 and is firmly pressed against the tapered surface 821.
Accordingly, since the one-way clutch member 8 is locked so as not to move with respect to the guide rod 5, only the drive rod 70 moves to the piezoelectric element 72 side.

Since the piezoelectric element 72 extends and the drive rod 70 moves to the syringe 2 side due to the operation as described above, the one-way clutch member 8, the pipe 9 and the piston 3 are moved by the amount of movement, and the liquid is discharged. The
On the other hand, even if the piezoelectric element 72 is reduced and the drive rod 70 moves to the piezoelectric element 72 side, the one-way clutch member 8 is locked so as not to move with respect to the guide rod 5. 9 and the piston 3 are stopped, and no liquid is discharged.
For this reason, when the piezoelectric element 72 repeatedly expands and contracts, the one-way clutch member 8, the pipe 9, and the piston 3 are intermittently moved only to the discharge port 21 side of the syringe 2 without returning in the reverse direction, and the liquid is discharged. The

As shown in FIG. 7, when the piston 3 moves to the end surface on the discharge port 21 side of the syringe 2 and finishes discharging the liquid inside the syringe 2, the protrusion 80 </ b> A and the protrusion 100 </ b> A are moved as described above. The one-way clutch member 8 is operated to be released, and the one-way clutch member 8, the pipe 9, and the piston 3 are moved to the piezoelectric element 72 side. Then, the pipe 9 is removed from the piston 3, the syringe 2 is removed from between the syringe base 4 and the syringe lid member 6, the syringe 2 is filled with the liquid, and the discharge of the liquid may be continued. The piston main body 31 may be removed by forming a female screw in the through-hole portion, screwing the attachment jig out of the syringe 2, and washing and reusing as appropriate.
Therefore, in the present embodiment, the guide rod 5, the drive unit 7, the one-way clutch member 8, the pipe 9, and the clutch release means 10 constitute a moving device that moves the piston 3. The first clutch means is configured by including a ball 86 that abuts against the drive rod 70 and a ring member 82 against which the ball 86 abuts, and the ball 86 that abuts against the guide rod 5 and the ball 86 A second clutch means is configured including a ring member 82 to be brought into contact with.

The controller adjusts the discharge speed by controlling the current flowing through the piezoelectric element 72 and adjusts the displacement amount of the piezoelectric element 72, that is, the discharge amount by controlling the voltage value applied to the piezoelectric element 72.
At this time, a sensor that detects the amount of displacement of the piezoelectric element 72, the drive rod 70, the one-way clutch member 8, the pipe 9 and the like that are displaced in conjunction with the piston 3, such as a capacitive sensor, a strain gauge, etc. By providing the detection data of these sensors and feeding back the detection data, the discharge amount set by the controller can be accurately controlled.

According to this embodiment, there are the following effects.
(1) Since the piston 3 is moved using the piezoelectric element 72, the liquid can be discharged with high accuracy even in a small amount. That is, for example, when 1 microliter of liquid is discharged with a syringe 2 having a diameter of 16 mm (cross-sectional area is approximately 200 mm ² ), the moving amount of the piston 3 is 5 μm. When using the conventional air pressure or using a ball screw or the like, it is difficult to make the positioning accuracy about 1 μm or less, so even if positioning can be performed with the highest accuracy of about 1 μm, The error in the discharge amount is about 0.2 microliter (20%).
On the other hand, in this embodiment, since the piezoelectric element 72 capable of positioning accuracy of about 0.1 μm is used, the discharge amount error is 0.002 microliters, and the error is very small as 0.2%. it can. Therefore, even a very small amount of liquid can be discharged with high accuracy.

(2) Since the response speed of the piezoelectric element 72 is as fast as about 0.01 msec, it is possible to realize a high-speed liquid ejection operation compared to a pneumatic or ball screw type drive having a response speed of about 10 msec. Furthermore, since the piezoelectric element 72 has a larger generation force than the air cylinder drive, even if the nozzle attached to the discharge port 21 is thinned and the resistance is increased, the liquid can be discharged and discharged. For this reason, for example, even 0.1 microliters of water can be blown cleanly, and a stable operation can be realized.

(3) Since the one-way clutch member 8 can make the forward and backward movement of the piezoelectric element 72 and the drive rod 70 into a one-way linear motion, the one-way clutch member 8 can have a compact configuration. Further, only one piezoelectric element 72 may be provided. Accordingly, since one piezoelectric element 72 is used as a driving source and the one-way clutch member 8 can be configured in a compact manner, the syringe pump 1 can be easily reduced in size as compared with a case where a driving mechanism such as a servo motor and a ball screw is employed. Can be
Therefore, in the production line of various products, when using the syringe pump 1 of this embodiment for discharging adhesives and various pastes, it can be attached to the robot arm and moved at high speed and high acceleration. The tact time of the production line can be shortened and it can contribute to productivity improvement.

(4) The amount of discharge liquid per unit time can be easily changed even during the discharge operation by changing the voltage value applied to the piezoelectric element 72 or changing the current value applied to the piezoelectric element 72. it can. For this reason, for example, in the step of attaching a plurality of electronic components on the substrate, in order to apply an adhesive having a different liquid amount for each attachment location of each electronic component, the amount of liquid discharged on the substrate may be changed or In a production line in which a plurality of products are mixed and sent, even when the discharge amount of the liquid has to be changed for each product, it is possible to provide a syringe pump 1 that can be easily handled and is easy to use.

(5) Since the one-way clutch member 8 is used, it is possible to reliably prevent the piston 3 from moving away from the discharge port 21 when the piezoelectric element 72 is driven. Therefore, the problem that the piston 3 moves in the opposite direction and air is sucked from the discharge port 21 and the amount of discharge liquid is contained when the discharge operation is performed next is included is surely prevented. it can. Furthermore, the syringe pump 1 can be used for injecting a chemical solution in which backflow is prohibited.
Since the one-way clutch member 8 has the same configuration as the portion disposed in the drive rod 70 portion and the portion disposed in the guide rod 5 portion, the manufacturing cost can be reduced accordingly.

(6) The one-way clutch member 8 can be realized with a simple configuration in which the ball 86 is disposed between the tapered surface 821 of the ring member 82 and the outer peripheral surface of each of the rods 5, 70. Can be reduced.
Further, when the drive rod 70 is advanced and retracted by the piezoelectric element 72, the one-way clutch member 8 is automatically switched to the locked state or the unlocked state, so there is no need to provide a special control mechanism for controlling on / off of the clutch. The configuration can be simplified and the cost can be reduced.
Further, the clutch release means 10 can be realized with a very simple configuration by moving the ball 86 to the portion having a large dimension between the tapered surface 821 and the outer peripheral surfaces of the rods 5 and 70 using the pin 102 or the like. .

(7) In this embodiment, since the syringe 2 can be easily exchanged, even if it is difficult to handle various drugs or liquid crystals, the syringe 2 sealed with the liquid is simply attached to the syringe base 4 part. Since the liquid can be discharged, deterioration of the liquid can be reliably prevented.

[Second Embodiment]
Next, a syringe pump 1A according to a second embodiment of the present invention will be described with reference to FIGS.
In the present embodiment, as shown in FIG. 8, spherical members 78 are provided instead of the resin sheet 77 on both end surfaces in the longitudinal direction (stretching direction) of the piezoelectric element 72, and the ball 86 in the one-way clutch member 8. The point which changed the structure which hold | maintains is different from the said 1st Embodiment. Accordingly, the same or similar components as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted or simplified.

  The spherical members 78 attached to both ends of the piezoelectric element 72 are formed in a hemispherical shape, and the outer peripheral surface 781 is a spherical surface. The spherical member 78 has a recess 782, and the end of the piezoelectric element 72 is disposed in the recess 782. Here, the bottom surface of the recess 782 is formed in a flat shape, and the end surface of the piezoelectric element 72 is bonded to the bottom surface with an adhesive such as an epoxy resin.

  The outer peripheral surface 781 of each spherical member 78 is in contact with the element case 74 and the element receiving member 76. Concave portions 742 and 762 are formed in the element case 74 and the element receiving member 76, respectively, and the outer peripheral surface 781 of the spherical member 78 is in contact with the concave portions 742 and 762. Thus, the element case 74 can be prevented from being subjected to a partial load.

In the one-way clutch member 8, a ring member 82 is disposed in a through hole formed in the clutch base 80 as in the first embodiment. The ring member 82 is clamped and fixed by a clutch base 80 and a pressing member 83 screwed to the clutch base 80.
However, in the embodiment, the push pin 84 that directly biases the ball 86 and the pin guide member 81 that guides the push pin 84 are provided. However, in the present embodiment, the movement of each ball 86 is within a certain range. The difference is that a ball cage 88 is provided which is regulated by.

As shown in FIG. 10, the ball cage 88 is formed in a substantially cylindrical shape, and the rods 5 and 70 are inserted through the central axis portion. A through hole 882 that penetrates in the radial direction is formed in the circumferential surface 881 of the ball cage 88. A plurality of the through holes 882 are provided at equal intervals along the circumferential direction. In the present embodiment, four through holes 882 are formed at intervals of 90 degrees.
The diameter of the through hole 882 is larger than the diameter of the ball 86, and the ball 86 is configured to be movable in the through hole 882.

  The ball holder 88 includes a magnet 883 that can attract the ball 86 corresponding to each through hole 882. The magnet 883 includes an axial direction 882A of the ball holder 88 passing through the center point of the through hole 882 and a direction orthogonal to the axial direction 882A, as shown in the developed views of the outer peripheral surface of the ball holder 88 shown in FIGS. It is provided in the diagonal position respectively offset with respect to the circumferential direction 882B to do. Specifically, the magnet 883 is provided at an oblique position offset from the center point of each through hole 882 on the first direction side (syringe table 4 side) and on the circumferential direction 882B side.

A disk-shaped spacer 89 is disposed on the clutch retainer 100 side (first direction side) of the ball cage 88, and a pin 102 is in contact with the spacer 89.
Here, the spacer 89 is made of a metal such as stainless steel, the ball cage 88 is made of oil-impregnated resin, and the ball cage 88 can be smoothly rotated with respect to the spacer 89 around the rods 5 and 70 as the rotation center. It is configured.

Further, the ball cage 88 is biased toward the syringe 2 by a spring 85. The urging force of the spring 85 is transmitted to the clutch pushing member 100 via the ball cage 88, the spacer 89, and the pin 102, and the clutch pushing member 100 moves to the syringe 2 side, that is, the flange of the movement restricting plate 103. The bush 104 is movable to a position where it comes into contact with the clutch base 80.
At this time, as shown in FIGS. 8 and 9, the through hole 882 of the ball cage 88 is formed so as to include the most range of the tapered surface 821 of the ring member 82, and in a state where the piezoelectric element 72 is not driven. The ball 86 is set so as to freely rotate in the through hole 882.

The liquid discharge operation in the syringe pump 1A of the second embodiment will be described.
The mounting of the syringe 2 may be performed in the same manner as in the first embodiment. When the piezoelectric element 72 is not driven after the syringe 2 is mounted, the ball 86 can also freely move within the range of the through hole 882 as shown in FIG. Therefore, the ball 86 is attracted by the magnet 883 and is in contact with the tapered surface 821 and each rod outer peripheral surface in the direction in which the magnet 883 is provided with respect to the center point of the through-hole 882, that is, at an obliquely lower position. It is positioned stably at the position.

Next, when the piezoelectric element 72 is driven by the controller and the drive rod 70 moves in the syringe table 4 side, that is, in the first direction, the ball 86 that contacts the drive rod 70 moves to the center point of the through hole 882 as shown in FIG. On the other hand, the taper surface 821 and the rod outer peripheral surface are pressed against each other at a position shifted to the circumferential direction 882B side to be in a locked state. Accordingly, as in the first embodiment, the one-way clutch member 8 moves in the first direction together with the drive rod 70, and the piston 3 moves in the first direction via the pipe 9 to discharge the liquid.
When the drive rod moves in the piezoelectric element 72 side, that is, in the second direction, the ball 86 that contacts the guide rod 5 is in the locked state as in the first embodiment, so that the one-way clutch member 8 does not move. Stopped.
Accordingly, the one-way clutch member 8 intermittently moves to the syringe 2 side and the piston 3 also moves in synchronization with the expansion / contraction operation of the piezoelectric element 72, so that the liquid in the syringe 2 is sequentially discharged.

When the liquid discharge is completed and the clutch 2 is released by operating the protrusions 80A and 100A to replace the syringe 2, the ball 86 is in an eccentric position from the center position of the through hole 882, and therefore, as shown in FIG. As described above, the ball 86 abuts against the inner peripheral surface of the through hole 882 obliquely below. The ball holder 88 sandwiched between the ball 86 and the spacer 89 is rotated in the circumferential direction around the rods 5 and 70, and the ball 86 that has been in contact with the through hole 882 along with this is also indicated by the arrow in FIG. Rotate as shown.
When the ball 86 rotates in this manner, the ball 86 moves upward, that is, in a direction in which the interval between the tapered surface 821 and the rod outer peripheral surface is wide, and the one-way clutch member 8 is unlocked.

In this embodiment as well, the same effects as the first embodiment can be obtained, and the following effects can also be obtained.
(8) A ball holder 88 having a through hole 882 having a diameter larger than that of the ball 86 is used, and a magnet 883 is provided in the ball holder 88 so that the ball 86 when the clutch is released is inserted into the through hole 882. The ball 86 can be displaced from the center of the through hole 882 when the clutch is locked. For this reason, when the clutch pushing member 100 is operated and the clutch is released, the ball holder 88 can be rotated in the circumferential direction by bringing the ball 86 into contact with the through hole 882, and accordingly, the ball 86 can also be rotated. Therefore, the ball 86 is more easily moved upward, that is, in a direction in which the interval between the tapered surface 821 and the rod outer peripheral surface is wide, and the friction of the contact portion with the tapered surface 821 and the rod outer peripheral surface is changed from static friction to dynamic friction. The force required to move the ball 86 and release the lock can be reduced.

(9) Since the spherical member 78 is provided at both ends of the piezoelectric element 72 and the spherical outer peripheral surface 781 of the spherical member 78 is in contact with each element case 74 and the element receiving member 76, the piezoelectric element 72 is biased unevenly. Can be prevented from being added. Therefore, it is possible to prevent the piezoelectric element 72 from being damaged by the partial load.

[Third Embodiment]
Next, a third embodiment of the present invention will be described with reference to FIGS.
In the syringe pump 1B of the present embodiment, the piston 3 is housed in the syringe 2 in the above embodiment, but the plunger 3A extended to the outside of the outer cylinder 2A that is a syringe is used as the piston. The difference is that the plunger 3A is arranged not on the axis of the drive rod 70 but in parallel with the drive rod 70, but the basic structure for moving the plunger 3A is the same as that of the above embodiments. is there.

That is, the outer cylinder (syringe) 2A is detachably attached to the syringe base 4A. That is, a substantially U-shaped groove 44 is formed in the syringe base 4A. A similar substantially U-shaped groove 48 is also formed in the holding plate 45 slidably provided on the syringe base 4 </ b> A via two parallel shafts 46. An operation lever 47 is connected between the ends of the shafts 46.
The holding plate 45, the shaft 46, and the operation lever 47 are urged toward the lower side (discharge port 21 side) in FIG. 14 by a spring (not shown), and the urging force holds the flange 25 of the outer cylinder 2A. 45 and the syringe base 4A. Therefore, the operation lever 47 is pushed upward (piezoelectric element 72 side) against the urging force of the spring, and the outer cylinder 2A is disposed in each of the grooves 44 and 48 of the syringe base 4A and the holding plate 45. When 47 is returned to the original position, the flange 25 of the outer cylinder 2A is held between the holding plate 45 and the syringe base 4A. That is, the syringe base 4A is detachably attached to the syringe base 4A by operating the operation lever 47.

As shown in FIG. 15, one end of each of the two guide rods 5 is fixed to the syringe base 4A. Further, the end of the drive rod 70 is inserted into the syringe base 4A.
That is, a stepped recess 401 is formed in the syringe base 4 </ b> A, and a rod receiving member 701 attached to the end of the drive rod 70 is inserted into the recess 401. A disc spring 73 as an urging means for urging the drive rod 70 toward the piezoelectric element 72 is interposed between the step portion of the recess 401 and the rod receiving member 701.

The other end of the guide rod 5 is attached to the base member 79. In addition, a drive rod 70 arranged in parallel between the guide rods 5 is inserted into the base member 79, and an element case 74 is attached.
In the element case 74, the piezoelectric element 72 is disposed in the same manner as in the above embodiment. The piezoelectric element 72 is disposed between the element case 74 and the drive rod 70 via the resin sheet 77. A ring-shaped element receiving member 76 for preventing the piezoelectric element 72 from falling off is attached to the end of the drive rod 70.

  As shown in FIG. 16, the one-way clutch member 8 </ b> A includes a first clutch base 181, a second clutch base 182, and a pressing member 183. The first clutch base 181 is formed with a through hole 185 through which the drive rod 70 is inserted in the same manner as the clutch base 80 of the above embodiment. The through hole 185 has a large diameter space on the syringe base 4A side, and a substantially cylindrical ball guide member 186 and a coil spring 187 for urging the ball guide member 186 toward the syringe base 4A are inserted therein. Has been.

  Further, the first clutch base 181 is formed with a protrusion 181A as shown in FIG. An abutment rod 189 as an abutment portion that abuts against the plunger 3A is fixed to the protrusion 181A. Further, the sensor rod 190 is fixed to the protrusion 181A, and is inserted into a potentiometer 74A fixed to the element case 74. Accordingly, the position of the one-way clutch member 8A relative to the drive rod 70 is detected by the potentiometer 74A, and the piezoelectric element 72 can be controlled in accordance with the position.

The second clutch base 182 is formed with a through hole 191 through which the drive rod 70 is inserted and a through hole 192 through which each guide rod 5 is inserted.
The through-hole 191 has a large diameter on the piezoelectric element 72 side, and the same ring member 82 as that of the first embodiment and the first clutch base 181 are inserted into the large diameter portion. The first clutch base 181 is fixed to the second clutch base 182 with screws or the like (not shown).
A return ring 87 is inserted in the small diameter portion so as to be movable in the axial direction. A ball 86 is disposed between the tapered surface 821 of the ring member 82 and the drive rod 70. Further, the ball guide member 186 is formed with a concave portion that holds the ball 86 in a circumferential direction along the outer peripheral surface of the drive rod 70 so that the ball 86 cannot move. The balls 86 are arranged at predetermined intervals in the circumferential direction. Yes.

Similarly to the first clutch base 181, a ball guide member 186 and a coil spring 187 are inserted into each through hole 192.
Also, pressing members 183 are screwed to the through-hole 192 portion of the second clutch base 182. In the holding member 183, a ring member 82, a ball 86, and a return ring 87 are arranged in the through hole portion through which the guide rod 5 is inserted, as in the above embodiment.

On the syringe base 4A side of the second clutch base 182, a clutch pushing member 200 constituting the clutch release means 10A is disposed. The clutch pressing member 200 is formed with a recess 201 and a pressing member 183 is disposed. Further, the clutch pushing member 200 is provided with a pin 202 that can be brought into contact with each return ring 87.
A movement restricting plate 211 is connected to the clutch pushing member 200 via a connecting plate 210. The movement restricting plate 211 is disposed on the base member 79 side of the second clutch base 182. For this reason, the clutch pushing member 200 urged by each coil spring 187 is movable in the direction of the syringe base 4 </ b> A to a position where the movement restricting plate 211 contacts the second clutch base 182.

  The movement restricting plate 211 is extended to the same position as the protruding portion 181A and protrudes from the second clutch base 182 and the clutch pushing member 200, and an operation formed in a U shape in FIG. A lever 212 is provided. When the operation lever 212 is brought closer to the protruding portion 181A side, the ball 86 is pushed through the pin 202 and the return ring 87, and the clutch is released as in the embodiment. Therefore, in this embodiment, the clutch pushing member 200, the pin 202, the connecting plate 210, the movement restricting plate 211, and the operation lever 212 constitute the clutch releasing means 10A.

In this embodiment as well, liquid ejection is performed by the same operation as in the above embodiments.
First, the outer cylinder 2A and the plunger 3A filled with the liquid are attached to the syringe base 4A by operating the operation lever 47. Next, the operation lever 212 is operated to release the clutch, and the one-way clutch member 8 is moved to bring the contact rod 189 into contact with the plunger 3A.
As described above, when the preparation for ejection is completed, the piezoelectric element 72 is driven. When the piezoelectric element 72 extends and the drive rod 70 moves to the syringe base 4A side, the first clutch base 181 moves to the syringe base 4A side together with the drive rod 70 by locking the ball 86 against the ring member 82. To do. Accordingly, the second clutch base 182 connected to the first clutch base 181 also moves to the syringe base 4A side. At this time, the ball 86 abutting on the guide rod 5 moves relative to the ball 86 toward the base member 79, so that the one where the gap between the tapered surface 821 and the guide rod 5 is wider. As in the above-described embodiment, the clutch for the guide rod 5 is released.
As the first clutch base 181 moves, the plunger 3A is pushed through the contact rod 189, and the liquid is discharged from the discharge port 21 of the outer cylinder 2A.

On the other hand, when the piezoelectric element 72 is reduced, the drive rod 70 is moved to the piezoelectric element 72 side by the disc spring 73. For this reason, as in the above-described embodiment, the ball 86 in contact with the drive rod 70 moves to the side where the distance between the tapered surface 821 and the drive rod 70 is wider, and the clutch for the drive rod 70 is released.
Even if the second clutch base 182 moves toward the base member 79 with respect to the guide rod 5, the guide rod 5 moves relative to the ball 86 relative to the syringe base 4A. Is in pressure contact with the tapered surface 821, and the clutch for the guide rod 5 is locked, so that the first clutch base 181 and the second clutch base 182 do not move, and the movement of the plunger 3A is also stopped.
Therefore, by repeating expansion and contraction of the piezoelectric element 72, the first clutch base 181 and the plunger 3A intermittently move to the syringe base 4A side, and the liquid is discharged.

  When the liquid discharge in the outer cylinder 2A is completed, the clutch is released by operating the operation lever 212, the first clutch base 181 and the second clutch base 182 are moved to the base member 79 side, and the outer cylinder 2A is replaced. Good.

In this embodiment as well, the same effects as the first embodiment can be obtained, and the following effects can also be obtained.
(10) Even if the plunger 3A having a length longer than that of the piston 3 is used, since the outer cylinder 2A and the plunger 3A are arranged in parallel to the drive rod 70, the overall length of the syringe pump 1B can be suppressed. it can.

In addition, this invention is not limited to the structure of the said Example, The deformation | transformation of the range which can achieve the objective of this invention is included in this invention.
The controller is preferably one that performs feedback control by detecting the amount of displacement of the piezoelectric element 72 or the like, but may be controlled without using feedback control, for example, control is performed using an experimentally obtained mathematical model. Good.

The spherical member 78 of the second embodiment may be used for the syringe pumps 1 and 1B of the first and third embodiments. In the second embodiment, a resin sheet 77 may be used instead of the spherical member 78. However, it is preferable to use the spherical member 78 because the piezoelectric element 72 can be prevented from being damaged.
Further, in the syringe pump 1B of the third embodiment, a ball holder 88 as in the second embodiment may be used. If this ball holder 88 is used, there is an advantage that the unlocking operability can be improved.

In the said 1st Embodiment, although the piston main body 31 was comprised separately from the push pipe 9, you may comprise integrally. However, if the piston main body 31 and the push pipe 9 are configured to be separable as in the first embodiment, the push pipe 9 may be attached after the piston main body 31 is inserted into the syringe 2. Therefore, the syringe pump 1 can be made compact.
In each of the above embodiments, the clutch mechanism (second clutch means) that restricts the movement of the one-way clutch members 8, 8 </ b> A with respect to the guide rod 5 is configured using the ball 86 and the ring member 82. However, you may comprise using a friction plate, for example. That is, it is only necessary to provide a releasing means for setting the frictional force by the friction plate to be smaller than the driving force of the piezoelectric element 72 and releasing the frictional state to release the locked state with respect to the guide rod 5. Even in such a configuration, if the piezoelectric element 72 is driven and the drive rod 70 is moved in the liquid discharge direction, the drive force is greater than the friction force of the friction plate. Move. On the other hand, when the drive rod 70 returns, the clutch base 80 is locked to the guide rod 5 by the frictional force, and the clutch base 80 does not move. Furthermore, if the release means is operated, the clutch base 80 can be returned to the piezoelectric element 72 side by manual operation. Therefore, the same operation as that in each of the above embodiments can be realized.

The syringe pumps 1, 1 </ b> A, 1 </ b> B of the present invention may be used by being incorporated in an electronic component manufacturing apparatus. That is, the electronic component manufacturing apparatus includes the above-described syringe pumps 1, 1 </ b> A, 1 </ b> B and a controller (control device) that controls the driving of the syringe pumps 1, 1 </ b> A, 1 </ b> B, and supplies the liquid necessary for manufacturing. An electronic component may be manufactured by discharging from the syringe pump 1.
In such an electronic component manufacturing apparatus, since the above-described syringe pumps 1, 1 </ b> A, and 1 </ b> B that can accurately transfer a very small amount of liquid are used, a very small amount of liquid can be discharged with high accuracy.

  INDUSTRIAL APPLICABILITY The present invention can discharge a small amount of liquid with high accuracy and at high speed, and can be used for a syringe pump used in fields such as semiconductor manufacturing and chemical dispensing.

It is a front view which shows the syringe pump of 1st Embodiment of this invention. It is sectional drawing along the AA line of FIG. It is sectional drawing along the BB line of FIG. It is sectional drawing which shows the structure of the drive part of the said embodiment, and a one-way clutch member. It is sectional drawing which shows the structure of the one way clutch member of the said embodiment. It is sectional drawing which shows the state which operated the clutch release means of the said embodiment. It is sectional drawing which shows the liquid discharge completion state of the said embodiment. It is sectional drawing which shows the principal part of the syringe pump of 2nd Embodiment of this invention. It is sectional drawing which shows the principal part of 2nd Embodiment. It is a perspective view which shows the ball holder of 2nd Embodiment. It is the expanded view which expand | deployed the outer peripheral surface of the ball holder of 2nd Embodiment. It is the expanded view which expand | deployed the outer peripheral surface of the ball holder of 2nd Embodiment. It is a front view which shows the syringe pump of 3rd Embodiment of this invention. It is sectional drawing which shows the principal part of 3rd Embodiment. It is sectional drawing which shows the principal part of 3rd Embodiment. It is sectional drawing which shows the principal part of 3rd Embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1,1A, 1B ... Syringe pump, 2 ... Syringe, 2A ... Outer cylinder, 3 ... Piston, 3A ... Plunger, 4, 4A ... Syringe stand, 5 ... Guide rod, 7 ... Drive part, 8, 8A ... One-way clutch Member: 9 ... Push pipe, 10, 10A ... Clutch release means, 70 ... Drive rod, 71 ... Rod advance / retreat mechanism, 72 ... Piezoelectric element, 73 ... Disc spring, 74 ... Element case, 76 ... Element receiving member, 78 ... Spherical surface Member, 80 ... clutch base, 81 ... pin guide member, 82 ... ring member, 84 ... push pin, 85 ... spring, 86 ... ball, 87 ... return ring, 88 ... ball cage, 100, 200 ... clutch push member, DESCRIPTION OF SYMBOLS 102 ... Pin, 181 ... 1st clutch stand, 182 ... 2nd clutch stand, 186 ... Ball guide member, 189 ... Contact rod, 821 ... Tapered surface, 882 ... Through-hole, 883 ... Stone.

Claims (9)

A syringe filled with liquid;
A piston that is disposed so as to be able to advance and retreat in the syringe, and that can push out and discharge the liquid filled in the syringe;
A moving device for moving the piston,
The mobile device is
A piezoelectric element;
A drive rod that is advanced and retracted in the direction of the movement axis of the piston with the expansion and contraction drive of the piezoelectric element;
A guide rod arranged parallel to the drive rod;
When the drive rod is disposed across the drive rod and guide rod and moves in the first direction, it is locked with respect to the drive rod and moves with the drive rod to push the piston and discharge the liquid. A one-way clutch member that is locked to the guide rod and stops without moving with the drive rod when the rod moves in the second direction opposite to the first direction;
Clutch release means for releasing the locked state of the one-way clutch member with respect to the drive rod and the guide rod so as to be freely movable with respect to each rod;
A syringe pump comprising: The syringe pump according to claim 1,
The one-way clutch member includes first clutch means that is switched between a locked state and an unlocked state with respect to the drive rod, and second clutch means that is switched between a locked state and an unlocked state with respect to the guide rod. ,
The first clutch means is locked with respect to the drive rod when the drive rod moves in the first direction and is moved together with the drive rod, and is driven when the drive rod moves in the second direction. It becomes unlocked with respect to the rod,
The second clutch means is unlocked with respect to the guide rod when the one-way clutch member moves in the first direction together with the drive rod, and the guide rod when the drive rod moves in the second direction. A syringe pump characterized by being locked with respect to the guide rod and prohibiting movement of the one-way clutch member relative to the guide rod. The syringe pump according to claim 2,
The drive rod and guide rod are made of round bars with a circular cross section,
The first clutch means and the second clutch means are respectively
A guide ring having a diameter larger than that of the drive rod and the guide rod and having a through hole through which the drive rod and the guide rod are inserted;
Arranged between the inner peripheral surface of the through hole of the guide ring and the outer peripheral surface of the drive rod and the guide rod, and a plurality of them are arranged at intervals along the circumferential direction of the outer peripheral surface of the drive rod and the guide rod. With the ball,
Biasing means for biasing the ball toward the first direction side,
The inner peripheral surface of the through hole of the guide ring includes a tapered surface whose diameter decreases as it goes in the first direction,
The diameter of the said ball | bowl is set larger than the minimum dimension among the dimensions between a drive rod and a guide rod, and a taper surface, and is set smaller than the maximum dimension, The syringe pump characterized by the above-mentioned. The syringe pump according to claim 2,
The drive rod and guide rod are made of round bars with a circular cross section,
The first clutch means and the second clutch means are respectively
A guide ring having a diameter larger than that of the drive rod and the guide rod and having a through hole;
A ball cage disposed in the through hole of the guide ring and having the drive rod and the guide rod inserted through a central axis portion;
A plurality of balls arranged one by one in each of the through holes formed at intervals along the circumferential direction of the ball cage,
The inner peripheral surface of the through hole of the guide ring includes a tapered surface whose diameter decreases as it goes in the first direction,
The diameter of the ball is set to be larger than the minimum dimension and smaller than the maximum dimension among the dimensions between the drive rod and guide rod and the tapered surface,
Each through hole of the ball holder is penetrated in the radial direction of the ball holder so that a ball disposed in the through hole can come into contact with the inner peripheral surface of each rod and guide ring, and the through hole The diameter of the ball is larger than that of the ball, and is offset in the circumferential direction with respect to the axial direction of the ball cage passing through the center point of the through hole on the first direction side with respect to the center point of each through hole. In each oblique position, a magnet capable of attracting the ball is provided for each through hole,
A syringe pump characterized in that the ball holder is rotatably provided with each rod as a rotation center. The syringe pump according to claim 3 or claim 4,
The syringe pump is characterized in that the clutch release means includes a ball moving member capable of moving the ball in the second direction by an external operation. The syringe pump according to any one of claims 1 to 5,
The one-way clutch member has a drive pipe having a drive rod inserted therein and one end fixed to the piston,
The said piston and syringe are provided on the axis of a drive rod and a drive pipe, The syringe pump characterized by the above-mentioned. The syringe pump according to any one of claims 1 to 5,
The piston and syringe are provided in parallel with the drive rod,
The syringe pump according to claim 1, wherein the one-way clutch member has a contact portion capable of contacting the end portion of the piston. The syringe pump according to any one of claims 1 to 7,
The piezoelectric element has one end surface in the expansion / contraction direction in contact with the element case through a spherical member, and the other end surface in contact with an element receiving member attached to the end of the drive rod through the spherical member. ,
Each spherical member has a contact surface with the piezoelectric element, the end surface of the piezoelectric element can be in close contact, and the contact surface with the element case and the element receiving member is a spherical surface,
The element receiving member is urged toward the second direction by an urging means and is in close contact with the spherical member of the piezoelectric element,
When the piezoelectric element extends, the element receiving member and the drive rod move in the first direction against the urging force of the urging means, and when the piezoelectric element contracts, the element receiving member and the driving rod are urged by the urging force of the urging means. Moves in the second direction. The syringe pump according to any one of claims 1 to 8,
A syringe pump comprising: a sensor that detects a displacement amount of the piezoelectric element or a displacement amount of the drive rod; and a control unit that controls a voltage value applied to the piezoelectric element in accordance with an output of the sensor.

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