JP4804116B2 - Method and apparatus for quantitative dispensing of liquid in which switching valve leakage is prevented - Google Patents

Description

  The present invention enables high-speed and high-accuracy liquids of all viscosities, for example, from low-viscosity substances such as water and alcohol to high-viscosity fluids such as adhesives, paste-like or cream-like industrial materials. The present invention relates to a discharging method and apparatus.

  2. Description of the Related Art Conventionally, in a device that discharges liquid in a fixed amount, a pneumatic discharge device that applies a regulated amount of compressed air to a liquid in a storage container for a desired time and discharges a desired amount of liquid from a discharge port at the nozzle tip Alternatively, a plunger-type discharge device has been developed in which a plunger disposed in a liquid-tight manner is moved to the liquid in the storage container to pressurize the liquid and discharge a desired amount of liquid from the discharge port at the tip of the nozzle.

Further, a cylinder is provided between the storage container and the nozzle, and a plurality of through holes provided in the cylinder are provided so that one plunger is advanced and retracted in one through hole, and the storage is performed by the retreating movement of the plunger. In the mechanism in which the liquid is sucked into the cylinder from the container and the liquid is discharged from the cylinder to the nozzle by the forward movement of the plunger, the plurality of plungers act on the liquid in order to pressurize the liquid, whereby the discharge port at the tip of the nozzle Multiple plunger pump type discharge devices have also been developed that discharge a desired amount of liquid.
Japanese Utility Model Sho 56-35570 JP 49-93930

  However, with these technologies, it is impossible to perform discharge with high accuracy and quantitativeness while maintaining a fast tact time as currently required. Because of the emergence of large devices with high functionality and the demand for higher tact to improve productivity, it is required to discharge a large amount in a short time, while high quality products are required. Since high-precision discharge and fine coating are required, all the switching valves used in the conventional apparatus have problems in order to satisfy such a requirement.

  For example, a pneumatic discharge device uses air pressure as a pressure source for discharging liquid. However, since air pressure is rich in compressibility, it is very difficult to change the pressure greatly in a short time, and therefore it has a high tact time. Even when a large amount of liquid is discharged in a short time and particularly when the liquid to be discharged is a high-viscosity liquid agent, it is necessary to apply a high pressure to the liquid. Since a rapid pressure change in the storage container is required, there is a limit to shortening the discharge time, and there is a problem that the discharge cannot be performed at high speed.

  In addition, the plunger-type discharge device is a method in which a plunger disposed in a liquid-tight manner in the vicinity of the liquid head in the storage container pressurizes and discharges all of the stored liquid, and the amount of pressurized liquid is stored. Since it depends on the amount of residual liquid in the container, the desired pressure arrival time when the liquid agent is pressurized to the desired pressure is faster when the residual liquid amount is small and slow when the residual liquid amount is large. . As described above, since the pressure change at the time of discharge differs depending on the amount of remaining liquid in the storage container, there is a problem that the discharge amount varies due to this, and if the amount of liquid to be stored in advance is small, a short cycle occurs. Thus, there is a problem that work efficiency is deteriorated because work for replacing the storage container is required.

  Furthermore, the multiple plunger pump type discharge device is a system in which a plurality of plungers sequentially pressurize the liquid, and when the control is transferred from one plunger to the other plunger, two liquids are simultaneously supplied. Since the pressure applied by the plunger is not uniform, the applied force is not uniform, and there is a problem that the pulsation is generated in the discharged liquid and the flow velocity is not uniform. For this reason, if liquid is applied and drawn on the workpiece in a linear shape with this device, unevenness and distortion occur in the line width and line height, and a uniform application shape cannot be formed. In this case, it is substantially impossible to form the coating.

  Therefore, the present inventor has provided a switching valve suitable for an apparatus for discharging liquid at high speed and high accuracy in order to solve these problems concerning high-speed and high-precision liquid discharge of liquid (Japanese Patent Application No. 11-350369). ).

By the way, as for the fixed_quantity | quantitative_quantity discharge apparatus of the said invention, as shown in FIG. 6, motor A20 is connected via the ball screw A23 and the gear A21.
The plunger rod A27 is attached to the plunger rod mounting plate A25 so as to move inward and backward with respect to the cylinder A29 by rotation of the motor A20.
The plunger rod B28 is attached to the plunger rod mounting plate B26 so as to move inward and backward with respect to the cylinder B30 by the rotation of the ball screw B24. When the plunger rod A27 moves forward, the plunger rod B28 moves backward. The gear B22 connected to the ball screw B24 is connected to the gear A21 so that the plunger rod B28 moves forward when the rod A27 moves backward.

Moreover, switching valve used in the apparatus, the valve block 34 is constituted by the pressing block 35 for holding the valve block 34 slidably in the cylinder block 31 and cylinder block 31 cooperate with retention cylinder A29 container Cylinder block 30 based on a signal from air control means 10 so that cylinder B30 and nozzle 15 communicate with each other, and cylinder B29 and storage container 14 communicate with each other when cylinder A29 and nozzle 15 communicate with each other. The flow path is switched by sliding the valve block 34 with respect to 31.

  To prevent leakage of the switching valve, the pressure block 35 at the tip of the air cylinder A36 presses and fixes the cylinder block with the air pressure supplied from the air control means 10, so that the valve block 34 is connected to the cylinder block 31 and the pressure block. Since it can slide relatively close to the block 35 and prevents leakage of unnecessary liquid, the air cylinder A36 and the cylinder 35 for generating a pressing force on the air cylinder A36 and the holding block 35 have a high pressure. The pipes 47 and 48 for supplying air are required, and further, means for controlling the amount of high-pressure air supplied to the air cylinder A36 is required, and the structure is complicated.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve these problems associated with high-speed and high-accuracy quantitative discharge of liquid and to provide a discharge method and apparatus for discharging liquid at high speed and high accuracy.
More specifically, the present invention eliminates these problems associated with high-speed and high-precision quantitative discharge of liquid, and further, a method and apparatus for discharging high-speed and high-precision liquid with simplified prevention of leakage of the switching valve. The purpose is to provide.

  The present invention is a liquid quantitative discharge method for sucking a liquid from a storage container into a cylinder by a backward movement of a plunger rod and discharging the liquid from the cylinder to a nozzle by an advance operation of the plunger rod. The gist of the method is to prevent leakage of the switching valve that communicates the cylinder and the storage container or nozzle by creating a sealing force corresponding to the pressure of the liquid to be driven.

  The flow path of the liquid discharged by the advancing operation of the plunger rod is branched into two, with one flow path leading to the discharge port and the other flow path creating a sealing force. A method for quantitatively discharging a liquid in which a liquid is sucked from a storage container into a cylinder by a retreating operation of the plunger rod, and discharged by discharging the liquid from the cylinder to a nozzle by an advancing operation of the plunger rod. The flow path of the liquid to be discharged by the operation is branched into two. One flow path is connected to the discharge port and the other flow path is created so as to create a sealing force, and the sealing force corresponding to the pressure of the liquid to be discharged is provided. This is a method characterized by preventing leakage of the switching valve that communicates between the cylinder and the storage container or nozzle.

  One discharge is performed by one suction operation and one discharge operation of the plunger rod. In this case, the present invention sucks the liquid from the storage container into the cylinder by the backward movement of the plunger rod, and the plunger rod The liquid is discharged and discharged from the cylinder to the nozzle by the advancing operation of the liquid, and the liquid is quantitatively discharged by one suction operation and one discharge operation of the plunger rod. By creating a sealing force according to the pressure of the liquid, preferably, the flow path of the liquid discharged by the advance operation of the plunger rod is branched into two, one flow path to the discharge port and the other flow path By creating a sealing force in accordance with the pressure of the liquid to be discharged, it is possible to prevent leakage of the switching valve that connects the cylinder and the storage container or nozzle. A method which is characterized in that stop.

  The liquid suction start position and the liquid discharge end position of the plunger rod are made equal. In this case, according to the present invention, the liquid is sucked into the cylinder from the storage container by the backward movement of the plunger rod, and the liquid is moved by the advancement of the plunger rod. Is discharged from the cylinder to the nozzle and discharged, and the liquid suction start position and the liquid discharge end position of the plunger rod are made equal. Preferably, one discharge is performed by one suction operation and one discharge operation of the plunger rod. In the method for quantitatively discharging liquid to be performed, preferably, by creating a sealing force according to the pressure of the liquid to be discharged, the flow path of the liquid discharged by the advance operation of the plunger rod is branched into two branches. The flow path of the other is connected to the discharge port, and the other flow paths are connected to create a sealing force, creating a sealing force according to the pressure of the liquid to be discharged. It makes it method characterized by preventing leakage of the switching valve for communicating the cylinder with the reservoir or nozzle.

  Set the liquid suction start position of the plunger rod for each discharge to the same position and the liquid suction end position of the plunger rod for each discharge to the same position, and / or the same liquid discharge start position of the plunger rod for each discharge The liquid discharge end position of the plunger rod for each discharge is set to the same position. In this case, the present invention sucks the liquid from the storage container into the cylinder by the backward movement of the plunger rod, and the plunger rod advances. The liquid is discharged from the cylinder to the nozzle by the operation and discharged, the liquid suction start position of the plunger rod for each discharge is set to the same position, and the liquid suction end position of the plunger rod for each discharge is set to the same position, and / Or the liquid discharge start position of the plunger rod for each discharge to the same position, and the liquid of the plunger rod for each discharge The discharge end position is set to the same position, preferably, the liquid suction start position and the liquid discharge end position of the plunger rod are equalized, and / or one discharge operation and one discharge operation of the plunger rod are performed once. A method for quantitatively discharging a liquid performed in a discharge operation, wherein a sealing force corresponding to the pressure of the liquid to be discharged is created, and the flow path of the liquid discharged by the advance operation of the plunger rod is preferably divided into two branches. One channel is connected to the discharge port, the other channel is connected so as to create a sealing force, and a sealing force corresponding to the pressure of the liquid to be discharged is created to communicate the cylinder with the storage container or nozzle. In this method, leakage of the switching valve is prevented.

Further, the present invention includes a nozzle for discharging liquid, a reservoir for storing the liquid, a cylinder with a plunger rod, and a drive means for driving the plunger rod, alternatively a cylinder and the storage container or nozzle A liquid dispensing apparatus comprising a switching valve in communication, wherein the switching valve has a first flow path communicating with a cylinder or a cylinder, and a cylinder having a second flow path communicating with a storage container A valve block having a block, a discharge channel that communicates the cylinder or the first channel and the nozzle, and a suction channel that communicates the cylinder or the first channel and the second channel; It pushed a holding block for holding the valve block slidably in the cylinder block and cooperate with a seal member disposed between the valve block and holding block, and valve block When the plunger rod of the cylinder is retracted, the switching valve communicates the cylinder and the storage container, and the cylinder and the discharge container are provided between the block and the space surrounded by the seal member. When the communication between the flow path, the gap and the nozzle is cut off and the plunger rod of the cylinder is advanced, the switching valve communicates the cylinder with the discharge flow path, the gap and the nozzle, and the cylinder and the storage. Abstract: A liquid dispensing apparatus characterized in that by blocking communication with a container, a part of liquid in a discharge channel flows into the gap and acts to press a valve block against a cylinder block. It is said.

  As shown in FIGS. 3 (a) and 3 (b), the switching valve is composed of a valve block 34 slidably mounted between a cylinder block 31 provided in the sub block 50 and a holding block 35. The cylinder block 31 is provided with three flow paths 31a, 31b, and 31c at equal intervals, and the valve block 34 communicates with the storage container attachment port 32 and either the cylinder A29 or the cylinder B30. The flow path 34a, and the flow path 34c communicating with either the cylinder A29 or the cylinder B30 via the 31a or 31c provided in the cylinder block 31 and the attachment port of the liquid feed tube A40 that pumps the liquid to the nozzle 15 are provided. A communicating channel 34b is provided.

  Further, the holding block 35 is provided with an O-ring 35a mounting groove so as to always surround a flow path 34d that moves in accordance with the switching operation of the valve block 34, and the groove is connected to the valve block 34 during discharge operation. An O-ring 35 a that prevents liquid from leaking from between the holding block 35 is fitted.

  The constant rate dispensing apparatus according to the first embodiment of the present invention configured as described above first sets the plunger rod A27 to the lowest position based on the work start signal from the control unit 11, and sets the switching valve to the state shown in FIG. Switch to. When the motor 20 is rotated in this state to raise the plunger rod A27, the cylinder A29 is stored through the flow paths 31a and 31b provided in the cylinder block 31, the flow path 34a provided in the valve block 34, and the storage container attachment port 32. Since the liquid in the storage container 14 is sucked into the cylinder A29 because it communicates with the container 14, the plunger rod B28 descends and reaches the lowest position at the same time as the plunger rod A27 reaches the uppermost position. The state shown in FIG.

  Next, when the plunger rod A27 reaches the uppermost position, a control signal is issued from the control unit 11, and when the switching valve is switched to the switching position shown in FIG. 3 (b), the cylinder A29 is connected to the cylinder block 31. The cylinder B30 communicates with the nozzle 15 via the flow paths 34b and 34c provided in the passage 31a and the valve block 34. The cylinder B30 includes the flow paths 31c and 31b provided in the cylinder block 31, the flow path 34a provided in the valve block 34, and The storage container 14 communicates with the storage container 14 through the storage container attachment port 32. In this state, when the rotation direction of the motor 20 is reversed by a control signal from the control unit 11, the plunger rod A27 descends to push the liquid in the cylinder A29 toward the nozzle 15, and the plunger rod B28 rises to raise the storage container 14. The liquid inside is sucked into the cylinder B30.

Hereinafter, the rotation direction control of the motor 20 and the switching operation of the switching valve are repeatedly performed, and the discharge operation is continued. The flow path 31a or 31b provided in the cylinder block 31 during the operation corresponds to the cylinder 29 or the liquid discharge operation. 30 and the flow paths 34b and 34d provided in the valve block 34 are communicated, and a part of the liquid discharged from the cylinder 29 or 30 is surrounded by an O-ring 35a between the valve block 34 and the holding block 35. It flows into the region and pushes the valve block 34 toward the cylinder block 31 to bring the cylinder block 31 and the valve block 34 into close contact with each other, thereby preventing liquid from leaking between the blocks.

The present invention is characterized in that a high-pressure liquid receiving gap surrounded by an O-ring is provided between the valve block and the holding block. In this case, the present invention includes a nozzle that discharges the liquid, a storage container that stores the liquid, A liquid dispensing apparatus comprising a cylinder block on which a cylinder having a plunger rod is mounted, a driving means for driving the plunger rod, and a switching valve for communicating the cylinder with a storage container or nozzle, the above switching valve, the valve block, the cylinder block and the press block and the cylinder block and cooperating to hold the valve block slidably, high pressure liquid, which is surrounded by an O-ring provided between the valve block and holding block The receiving air gap causes a part of the high-pressure liquid to be discharged to act on the back of the valve block and Which is a dispensing system for a liquid which is characterized by being configured to press the valve seat surface formed in the cylinder block.

In the liquid dispensing apparatus, the storage container and the switching valve and / or the nozzle and the switching valve are configured to communicate with each other via a liquid feeding pipe .

Further, the liquid dispensing apparatus described above is characterized by comprising a pressurizing means for pressurizing the liquid in the storage container .

In the above-described liquid dispensing apparatus, the plunger rod diameter is substantially equal to the cylinder inner diameter, preferably the plunger rod is inscribed in the cylinder, more preferably the outer cross-sectional shape inscribed in the cylinder of the plunger rod is circular. It is characterized by its shape .

In the above-described liquid dispensing apparatus, the switching valve is a slide valve having a valve block having a first hole communicating with the storage container and a second hole communicating with the nozzle, and preferably is brought into close contact with pressure. The slide valve, more preferably its sliding surface, is characterized in that the contact area is minimized .

The device of the present invention is characterized in that the driving means and / or the switching valve is configured to operate based on a signal from the control unit.
Further, the apparatus of the present invention has a plurality of plunger rods, preferably the drive means is made equal to the number of plunger rods, more preferably the switching valve while maintaining the relative distances of the rod tips of the plurality of plunger rods. The plunger rod position adjusting means for adjusting the relative distance between the plunger rod and the plunger rod is provided, and / or the plunger rod is configured to be independently controllable.
Furthermore, the apparatus according to the present invention may perform the suction operation or stop operation of the other plunger rod and / or the discharge operation speed of the plunger rod in the discharge operation of any one of the plunger rods. The speed is different from the speed.

  As described above, since the present invention uses the pressure of the liquid discharged to the seal between the valve block and the cylinder block, other force sources, for example, members such as an air cylinder as in the invention of Japanese Patent Application No. 11-350369 In addition, since the liquid pressure and the sealing force, that is, the contact force between the valve block and the cylinder block are proportional, it is possible to create a sealing force according to the liquid pressure, and the valve block operation due to excessive contact force. Liquid leakage due to defects or insufficient adhesion can be prevented.

  Since one discharge is performed by one movement of the plunger rod, there is no pulsation in the discharged liquid and it is possible to discharge the liquid at a constant flow rate. Can be applied and formed. Moreover, since the position of the plunger rod at the start and end of discharge for each discharge is always constant, the liquid compression amount is always constant regardless of the amount of liquid stored in the container, and stable high-precision discharge is performed. be able to.

  Furthermore, since the amount of liquid to be discharged at one time is sucked into the cylinder and the liquid in the cylinder is discharged by applying pressure by moving the plunger rod, the amount of liquid to be pressurized can be minimized. Therefore, it is possible to effectively eliminate the influence caused by the liquid, and furthermore, it is possible to greatly shorten the time from when the liquid is pressurized until the liquid is discharged from the nozzle, enabling high-speed discharge And

The present invention relates to a liquid discharge method in which a liquid is sucked from a storage container into a cylinder by a backward movement of a plunger rod, and the liquid is discharged from a cylinder to a nozzle by an advance operation of the plunger rod. This is a liquid discharge method performed by a single suction operation and a single discharge operation of the plunger rod.
Accordingly, since the liquid is not pressurized by a plurality of plungers at the same time, the pressure applied to the liquid is constant, so that no pulsation is generated in the discharged liquid and the flow velocity is uniform. For this reason, even if the liquid is applied and drawn on the workpiece in a linear shape, the width and height of the line are not uneven or distorted, and a uniform applied shape can be formed. Can be formed.

The above method is characterized in that leakage of the switching valve that connects the cylinder and the storage container or nozzle is prevented by creating a sealing force according to the pressure of the liquid to be discharged.
The flow path of the liquid discharged by the advancing operation of the plunger rod is branched into two, with one flow path leading to the discharge port and the other flow path creating a sealing force.

  Moreover, since the discharge means that the liquid flows out from the nozzle due to the pressure difference between the liquid induced by pressurizing the liquid and the atmospheric pressure, the liquid is pressurized in order to effectively induce the pressure difference. The smaller the volume of the liquid, the better. The liquid pressure can be increased more steeply, which is effective when a large amount of liquid is discharged in a short time and particularly when the liquid to be discharged is a high-viscosity liquid agent. Therefore, it is preferable to pressurize a single discharge amount by sucking the liquid into the cylinder rather than pressurizing a liquid amount corresponding to a plurality of discharge amounts. More preferably, there is no remaining amount of liquid in the cylinder after completion of liquid discharge of the plunger rod.

  Here, it is preferable that the liquid suction start position and the liquid discharge end position of the plunger rod are made equal for each discharge. The amount of liquid to be pressurized at each discharge is always kept constant because the amount of liquid to be pressurized does not depend on the amount of remaining liquid in the storage container, and the liquid when the plunger rod pressurizes the liquid at the time of discharge. Since the process of increasing the pressure can be made equal for each discharge, there is no variation in the discharge amount depending on the remaining liquid amount in the storage container. More preferably, the liquid discharge start position of the plunger rod for each discharge is set to the same position, and the liquid discharge end position of the plunger rod for each discharge is set to the same position. More preferably, the liquid suction start position of the plunger rod for each discharge is set to the same position, and the liquid suction end position of the plunger rod for each discharge is set to the same position.

A specific device configuration includes a nozzle that discharges liquid, a storage container that stores liquid, a cylinder that has a space inside, a plunger rod that is inscribed and retracted in contact with the cylinder, and a drive unit that drives the plunger rod. And a liquid metering discharge device comprising a switching valve that communicates the cylinder and the storage container or nozzle.
The above switching valve, the valve block, and the cylinder block and the cylinder block cooperate with the holding block for holding the valve block slidably, part of the high pressure liquid to be discharged to act on the rear surface of the valve block, The valve block is configured to be pressed against a valve seat surface formed in the cylinder block.
That is, the discharge device discharges the liquid, the storage container that stores the liquid, the cylinder, the plunger rod that advances and retreats inside the cylinder, the driving means that drives the plunger rod, the cylinder, the storage container, or the nozzle. In the liquid metering device comprising a switching valve communicating with the liquid, the liquid metering device in which the valve block having a flow path is slidably disposed between the cylinder block and the holding block. It is characterized in that a part of the high-pressure liquid to be applied acts on the back surface of the valve block and presses the valve block against the valve seat surface formed on the cylinder block. Further, a seal member ( wherein the O-ring) by providing high pressure liquid receiving voids surrounded by.

In this device, the plunger rod connected to the driving means moves forward and backward in contact with the inner wall, the plunger rod moves backward by an amount equal to the discharge amount, sucks liquid from the storage container into the cylinder, and the plunger rod reaches the discharge amount. Ejection is performed by moving forward by an equal amount and discharging liquid from the cylinder to the nozzle.
At this time, the switching valve communicates the cylinder and the storage container when the plunger rod moves backward to suck liquid into the cylinder, and communicates the cylinder and nozzle when the plunger rod moves forward and discharges the liquid from the cylinder. Operates as follows.

By connecting the storage container and the switching valve via the liquid feed pipe, the liquid agent storage part and the discharge mechanism part can be separated, so that the storage container can be arranged in an easy-to-handle place, For example, when the remaining amount of the liquid in the storage container is reduced, it is possible to easily perform the operation of replenishing the liquid storage container with the liquid or exchanging the storage container filled with the liquid in advance.
Furthermore, the amount of liquid stored in the container can be stored in a planned manner, considering the pot life of the liquid to be used and the daily work amount. It is possible to dispense with the replenishment work or to replenish appropriately.

  Further, since the discharge mechanism and the discharge port can be separated by communicating the nozzle and the switching valve via the liquid feed pipe, the discharge mechanism is installed in the fixed part, and the nozzle is moved to the movable part, for example, a robot. Therefore, the movable part can be made extremely lightweight. This makes it possible to carry out a coating operation, for example, a drawing operation for applying a desired pattern shape on the workpiece surface at a very high speed.

  When the liquid in the storage container is a highly viscous fluid, or when the liquid is quickly sucked into the cylinder, the suction force by the backward movement of the plunger rod is assisted to feed the liquid in the storage container to the cylinder. In order to do so, it is preferable to provide a pressurizing device for pressurizing the liquid in the storage container.

Further, the diameter of the plunger rod that slides into the piston is preferably substantially equal to the cylinder inner diameter. More preferably, the plunger rod is inscribed in the cylinder.
Further, the outer cross-sectional shape inscribed in the cylinder of the plunger rod diameter can be circular.

The switching valve can be a ball valve.
Preferably, the switching valve is a slide valve having a first block that communicates with the storage container and a second hole that communicates with the nozzle, and a valve block that slides and switches a site that communicates.
As the first hole and the second hole are adjacent to each other, the loss time at the time of switching can be shortened and the discharge can be performed with a high tact time.

The driving means and / or the switching valve can operate based on a signal from the control unit.
Preferably, the switching valve is controlled so that the plunger rod communicates with the nozzle at the time of discharge, and further, the liquid is pressurized by controlling the driving means, and the switching valve is communicated with the storage container at the time of suction. And the liquid is sucked by controlling the driving means.

The number of plunger rods can be plural.
At this time, since a plurality of discharges can be performed with different plunger rods each time, in the discharge operation of any one of the plunger rods, the other plunger rods perform suction or stop operation, so that at the next discharge Since the plunger rod that has sucked the liquid can quickly discharge the liquid, the time required for effectively sucking the liquid can be made unnecessary, and a faster tact time can be achieved.

Furthermore, it is possible to make the drive means equal to the number of plunger rods.
Further, the plunger rod can be controlled independently.
At this time, the discharge operation speed of the plunger rod when one plunger rod discharges the liquid and the suction operation speed when the other plunger rod sucks the liquid into the cylinder can be easily adjusted to different speeds. Therefore, it is preferable that one of the plurality of plunger rods can be set to a speed suitable for discharge when the plunger rod is involved in discharge, and is preferably suitable for suction when engaged in the suction.

[Action]
The operation principle of the present invention will be described with reference to FIG.
The holding block 5 and the cylinder block 1 constituting the switching valve are fixed to the base plate, and the valve block 4 is slidably disposed between the blocks 5 and 1. A cylinder 2 provided with a plunger rod 3 is mounted. Further, the cylinder block 1 is provided with a flow path 1 b that leads from the liquid source to the flow path 4 a of the valve block 4. Further, the holding block 5 is provided with an O-ring so as to always surround the opening of the flow path 4 b that communicates with the holding block 5 provided in the valve block 4.

  The valve block 4 is provided with a flow path 4a and a branched flow path 4b, one of which is connected to the discharge port and the other is connected to the holding block 5. When sucking, the cylinder 2 and the flow path 4a are communicated with each other, and when discharging the liquid, the cylinder 2 and the flow path 4b are communicated with each other. When the rod 3 is pressurized by the advancing operation of the rod 3 and flows out to the valve block 4, a part of the liquid flows into the gap surrounded by the O-ring 6 between the valve block 4 and the holding block 5. It can be moved in the direction of the cylinder block 1 to bring them into close contact with each other and prevent liquid leakage between them.

  Details of the present invention will be described with reference to the drawings. However, the present invention is not limited to these embodiments.

  The motor A20 is connected via a ball screw A23 and a gear A21. The plunger rod A27 is attached to the plunger rod mounting plate A25 so as to move inward and backward with respect to the cylinder A29 by the rotation operation of the motor A20. The plunger rod B28 is attached to the plunger rod mounting plate B26 so as to move forward and backward in contact with the cylinder B30 by the rotation of the ball screw B24. When the plunger rod A27 moves forward, the plunger rod B28 moves backward. The gear B22 connected to the ball screw B24 is connected to the gear A21 so that the plunger rod B28 moves forward when the plunger rod A27 moves backward.

  The switching valve is composed of a valve block 34 and a cylinder block 35. The cylinder B30 and the nozzle 15 communicate with each other when the cylinder A29 and the storage container are connected, and the cylinder B30 when the cylinder A29 and the nozzle 15 communicate with each other. The valve block 34 is slid with respect to the cylinder block 31 based on a signal from the air control means 10 so that the storage container 14 communicates with the storage container 14.

  As shown in FIG. 3, the switching valve has a valve block 34 slidably mounted between a cylinder block 31 and a holding block 35 provided in the sub-block 50. The cylinder block 31 is provided with three flow paths 31a, 31b, and 31c at equal intervals. The valve block 34 is provided with a flow path 34a for selectively communicating the storage container attachment port 32 with either the cylinder A29 or the cylinder B30. A flow path 34b for providing communication between the other cylinder and the discharge port 34c is provided. The flow path 34 d is branched and opened at the contact surface between the valve block 34 and the holding block 35. The pressing block 35 is provided with an O-ring 35a that always surrounds the opening of the flow path 34d that communicates with the discharge port 34c.

  The switching valve in this embodiment has the above-described configuration, and when the liquid is discharged from the cylinder A29 or the cylinder B30, the liquid is pumped in the direction of the nozzle 15, but at this time, a part of the liquid is in the valve block 34 and the holding block 35. It flows into the area surrounded by the O-ring 35a between them and presses the valve block 34 toward the cylinder block 31 to bring 31 and 34 into close contact with each other, thereby preventing liquid from leaking from between both blocks.

  The motor B38 is connected to the ball screw C39, and the relative distance between the base block 49 and the sub block 50 can be changed in the axial direction of the ball screw C39 by the rotational operation of the motor B38. A23, Ball screw B24, Plunger rod A27, Plunger rod B28, Plunger rod mounting plate A25, Plunger rod mounting plate B26 are fixed, and cylinder A29, cylinder B30, cylinder block 31, nozzle 15 and valve block are attached to sub block 50 34 is fixed.

  Therefore, the fact that the relative distance between the base block 49 and the sub block 50 can be moved in the rotational direction of the ball screw C39 is that the relative distance between the plunger rod A27 and the plunger rod B28 is kept constant, Since the relative distance with respect to 34 can be adjusted, when the plunger rod that performs a small amount of discharge is slightly displaced, the plunger rod can be brought close to the valve block 34, and unnecessary liquid remains in the cylinder. It can be effectively removed.

  Further, when the center of the maximum stroke amount that the plunger rod moves forward and backward is the position where the tip of the plunger rod A27 and the tip of the plunger rod B28 are aligned, when discharging an amount that does not require the maximum stroke, for example, a small amount is discharged. In such a case, the actuator moves forward and backward by a slight amount compared to the maximum stroke amount of the plunger rod. At this time, the liquid from the plunger rod tip position at the end of the discharge to the valve block 34 functions as a buffer. Therefore, it is preferable to exclude the liquid as the buffer particularly when discharging at high speed tact.

  In the first embodiment, the storage container 14 can be appropriately replenished with liquid or replaced with another storage container 14 in which the liquid is stored. The air cylinder B37 is connected to the air control means 10 and can supply air as required. The air control means 10, the motor A20, and the motor B38 are connected to the control unit 11. And operates based on a signal from the control unit 11.

Next, the discharge operation of the apparatus will be described over time.
1. The distal ends of the plunger rod A27 and the plunger rod B28 are adjusted to a position (aligned position) that is equidistant from the cylinder block. This position is the base position.
2. The plunger rod A27 is moved forward by driving the motor A20 by a volume that is half the desired discharge amount. At this time, the rotation of the motor A20 is transmitted to the gear B22 via the gear A21 so that the plunger rod B28 moves backward by half the volume of the desired discharge amount.

3. At this time, the amount of advancement of the plunger rod A27 from the reference position is the maximum when the desired amount is discharged, and therefore the motor B38 is driven so that the tip position of the plunger rod A27 approaches the valve block 34. Then, the relative distance between the base block 49 and the sub-block 50 is adjusted so that the remaining amount of liquid in the cylinder A29 is minimized and preferably zero. At this time, since the plunger rod A27 and the plunger rod B28 are integrally translated by driving the motor B35, the relative distance between the plunger rod A27 and the plunger rod B28 does not change.
4). Here, the position of the valve block 34 is adjusted so that the storage container and the cylinder A29 communicate with each other, that is, the nozzle 15 and the cylinder B30 communicate with each other.
5. Next, the cylinder B30 is moved forward by driving the motor A20 by a desired discharge volume. At this time, the rotation of the motor A20 causes the plunger rod A27 to move backward by the desired discharge volume, so that the liquid in the storage container 14 is sucked into the cylinder.

6). Furthermore, the position of the valve block 34 is adjusted so that the storage container 14 and the cylinder B30 communicate with each other, that is, the nozzle 15 and the cylinder A29 communicate with each other.
7). The cylinder A29 is moved forward by driving the motor A20 by a desired discharge volume. Since the cylinder A29 is filled with a desired amount of liquid, the liquid is discharged from the discharge port at the tip of the nozzle 15 by driving the motor A20. Further, the storage container 14 and the cylinder B30 are in communication with each other. At this time, the plunger rod B28 moves backward by a desired discharge volume amount by the rotation of the motor A20, so that the liquid in the storage container 14 is sucked into the cylinder B30.
Thereafter, the above-described operations 5 to 7 are repeated to continuously discharge the liquid to form a desired coating pattern. Thus, the discharge is performed by the advancement of one plunger, and at the same time the other one Since the plunger sucks the liquid into the cylinder, the discharge operation can be performed at a high speed tact.

In the second embodiment, motors 60 and 61 are connected to the two plunger rods 27 and 28, respectively, and air pressure is applied to the liquid in the storage container 14 so that the liquid can be quickly filled into the cylinders 29 and 30 from the storage container 14. This is an applied example. (FIG. 4 (a) and FIG. 4 (b) are both device diagrams showing the second embodiment, and the same device is described by changing the angle.
In FIG. 4A, the storage container 14, the air control means 10, and the nozzle 15 are not drawn, and in FIG. 4B, the control unit 11 is not shown. The storage container 14, the air control means 10, the nozzle 15, and the control part 11 are attached to both Fig.4 (a) and FIG.4 (b). The air control means 10 is also connected to the control unit 11 and controlled by the control unit 11. These figures are omitted to avoid obfuscation depending on the angle. )

The main features of Example 2 are as follows.
i) Since the motors 60 and 61 are connected to the two ball screws 23 and 24, respectively, the two plunger rods 27 and 28 can be moved independently. As a result, the discharge and suction speeds can be changed, so that it is possible to reduce the filling speed without changing the discharge speed in a liquid that takes a long time for suction, and suction that is inappropriate for the liquid. It is possible to suppress the occurrence of cavitation without applying force.
ii) By rotating the two independent motors 60 and 61 in the same direction, the plunger rod A27 and the plunger rod B28 and the valve block 34 are kept at a constant relative distance between the plunger rod A27 and the plunger rod B28. Therefore, in the second embodiment, it is unnecessary to separate the base block and the sub-block as in the first embodiment and slide them with a motor.
iii) Since the air inside the storage container 14 can be pressurized by the air control means 10 so that the liquid can be quickly sucked into the cylinders 29 and 30 from the storage container 14, the supply of liquid to the cylinder can be performed at a high speed. This makes it possible to perform the discharge operation with a faster tact time. Great effect when discharging high viscosity liquid.
Further, since the storage container 14 and the cylinder block 31 are connected by the liquid feed tube 64 and the valve block 34 and the nozzle 15 are connected by the liquid feed tube 40, the storage container 14, the pump body and the nozzle 15 are connected. Even when the pump main body must be installed in a place where the pump main body cannot be reached, the storage container 14 can be installed at hand, so that the liquid disappears and the storage container 14 is removed. Useful when replacing.

FIG. 5 shows an embodiment in which the constant rate dispensing apparatus of the second embodiment is used for an XYZ robot (coating robot) 72, and the nozzle 15 connected from the valve block 34 of the pump body 70 via the liquid feed tube 64 is connected to the XYZ robot. It is mounted on the robot 72 and is connected to the storage container 14 from the cylinder block 31 of the pump body 70 via the liquid feed tube 64, and the storage container 14 has an air control function via the air tube 63. The controller 71 is connected to each motor of the pump body and can control the motor.
Therefore, the head of the XYZ robot can be lightened compared to the conventional case where the entire storage container is mounted on the XYZ robot, so that the relative movement between the nozzle and the work table can be performed quickly and smoothly. Thus, stable application can be performed, and as can be seen from the figure, the nozzle 15, the pump main body 70, the control unit 71, and the storage container 14 can be arranged at different locations. Things that are frequently handled, such as, can be placed in a place where it is easy to work.

It is the schematic explaining the working principle of this invention. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a general view of a first embodiment of a liquid dispensing apparatus to which a leakage preventing apparatus according to the present invention is applied. FIG. 3 is an enlarged view of a main part of FIG. 2. It is the whole figure of Example 2 of the fixed_quantity | quantitative_discharge apparatus of the liquid which gave the leakage prevention apparatus of this invention. It is a whole figure of the fixed_quantity | quantitative_discharging apparatus of the liquid which mounted the leakage prevention apparatus of this invention of Example 2 on the XYZ robot. 1 is an overall view of one embodiment of a prior invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cylinder block 2 Cylinder 3 Plunger rod 4 Valve block 5 Holding block 6 O ring 10 Air control means 11 Control part 12 Air tube A
13 Air tube B
14 Storage container 15 Nozzle 20 Motor A
21 Gear A
22 Gear B
23 Ball screw A
24 Ball screw B
25 Plunger rod mounting plate A
26 Plunger rod mounting plate B
27 Plunger rod A
28 Plunger rod B
29 Cylinder A
30 Cylinder B
31 Cylinder block 32 Storage container attachment port 33 Support arm 34 Valve block 35 Holding block 36 Air cylinder A
37 Air cylinder B
38 Motor B
39 Ball screw C
40 Liquid feed tube A
41 Air cylinder B air tube mounting port 1
42 Air cylinder B air tube mounting port 2
43 Air Tube C
44 Air tube D
45 Air tube A air tube mounting port 1
46 Air tube mounting port 2 of air cylinder A
47 Air Tube E
48 Air Tube F
49 Base block 50 Sub block 60 Motor C
61 Motor D
62 Motor E
63 Air tube G
64 Liquid feed tube B
70 Pump body (Example 3)
71 Control means (including air control means)
72 Dispensing robot (XYZ robot)
73 Storage container holder

Claims (15)

While switching the communication between the cylinder and the storage container or nozzle by the switching valve, the plunger rod retracts to suck the liquid into the cylinder, and the plunger rod advances to discharge the liquid from the cylinder to the nozzle for discharge. A method for quantitatively discharging a liquid,
The switching valve is a cylinder block having a first flow path communicating with a cylinder or a cylinder, a second flow path communicating with a storage container, and a discharge for communicating the cylinder or the first flow path with a nozzle. A valve block having a flow path and a suction flow path that communicates the cylinder or the first flow path and the second flow path; and a holding block that slidably holds the valve block in cooperation with the cylinder block And a seal member disposed between the valve block and the pressing block, and a gap provided between the valve block and the pressing block and surrounded by the sealing member,
When the plunger rod of the cylinder is moved backward, the cylinder and the storage container are communicated by the switching valve, and the communication between the cylinder and the discharge flow path, the gap and the nozzle is blocked, and the suction flow path is connected. Aspirating liquid from the storage container into the cylinder; and
When the plunger rod of the cylinder is advanced, the cylinder and the discharge flow path, the gap and the nozzle are communicated with each other by the switching valve, and the communication between the cylinder and the suction flow path is blocked, and the liquid is discharged from the nozzle. Along with discharging, a part of the liquid in the discharge channel flows into the gap so that the valve block is pressed against the cylinder block, creating a sealing force according to the pressure of the liquid to be discharged and switching A liquid dispensing method characterized by preventing leakage of a valve.   The method of dispensing a liquid according to claim 1, wherein the switching valve is a slide valve, and the valve block is slidably held.   3. The liquid quantitative discharge method according to claim 1, wherein one discharge is performed by one suction operation and one discharge operation of the plunger rod. Set the liquid suction start position of the plunger rod for each discharge to the same position and the liquid suction end position of the plunger rod for each discharge to the same position , and / or set the liquid discharge start position of the plunger rod for each discharge. 4. The liquid quantitative discharge method according to claim 1, wherein the liquid discharge end position of the plunger rod for each discharge is set to the same position at the same position . It said plunger rod is more, during the discharge operation of any one of the plunger rod, one of dispensing method of the liquid of claim 1-4 for sucking operation of the other of the plunger rod. A nozzle that discharges liquid, a storage container that stores liquid, a cylinder that includes a plunger rod, a drive unit that drives the plunger rod, and a switching valve that selectively communicates the cylinder and the storage container or nozzle. A liquid dispensing device comprising:
The switching valve is a cylinder block having a first flow path communicating with a cylinder or a cylinder, a second flow path communicating with a storage container, and a discharge for communicating the cylinder or the first flow path with a nozzle. A valve block having a flow path and a suction flow path that communicates the cylinder or the first flow path and the second flow path; and a holding block that slidably holds the valve block in cooperation with the cylinder block And a seal member disposed between the valve block and the pressing block, and a gap provided between the valve block and the pressing block and surrounded by the sealing member,
When the plunger rod of the cylinder moves backward, the switching valve communicates the cylinder and the storage container, and blocks communication between the cylinder and the discharge flow path, the gap and the nozzle.
When the plunger rod of the cylinder is advanced, the switching valve communicates the cylinder with the discharge flow path, the gap and the nozzle, and cuts off the communication between the cylinder and the storage container. A liquid dispensing apparatus characterized in that a part of the liquid in the passage flows into the gap and presses the valve block against the cylinder block. The liquid dispensing apparatus according to claim 6 , wherein the switching valve is a slide valve, and the valve block is slidably held. The storage container and the switching valve are configured to communicate with each other via a liquid feeding pipe , and / or the nozzle and the switching valve are configured to communicate with each other via a liquid feeding pipe. The liquid dispensing apparatus according to claim 6 or 7 . Either dispensing system for a liquid according to claim 6-8, characterized in that comprises a pressurizing means for pressurizing the liquid in the storage container. Either dispensing system for a liquid according to claim 6-9, characterized in that it has substantially equal to the inner diameter of said the diameter of said plunger rod cylinder. Either dispensing system for a liquid according to claim 6-10, wherein the plunger rod is inscribed in a cylinder. 12. The liquid dispensing apparatus according to claim 11 , wherein the outer cross-sectional shape inscribed in the cylinder of the plunger rod is circular. The liquid dispensing apparatus according to any one of claims 6 to 12 , wherein the driving unit and the switching valve are configured to operate based on a signal from a control unit. The liquid quantitative discharge device according to any one of claims 6 to 13 , wherein the discharge operation speed and the suction operation speed of the plunger rod can be controlled to different speeds, respectively. The liquid dispensing apparatus according to any one of claims 6 to 14 , wherein one discharge is performed by one suction operation and one discharge operation of the plunger rod.

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