JP4524103B2 - Liquid ejection device - Google Patents

Description

  The present invention relates to a liquid discharge apparatus that sucks and discharges liquid using reciprocation of a plunger.

A plunger pump type liquid discharge device (dispenser) that can discharge a very small amount of liquid with high accuracy and is used for adhesive discharge in a semiconductor manufacturing process is known (for example, Patent Document 1).
The liquid discharge device includes a valve block having a sliding contact surface in which a communication hole communicating with the suction port and the discharge port is opened, and the sliding contact surface of the valve block is in contact with the sliding contact surface at one end. And a pump block having three plunger insertion holes drilled in the axial direction in a state of being able to communicate with the opening of the communication hole of the valve block. The plunger insertion holes are sequentially communicated with the communication holes by being rotated while being urged toward the block side, and the plungers in the plunger insertion holes are driven in the axial direction to sequentially repeat the suction and discharge of the liquid. Thereby, it has the outstanding characteristic that a very small amount of liquid can be discharged without a pulsation and for every fixed quantity.

JP-A-6-129345

By the way, the liquid discharge device rotates the pump block while energizing the pump block toward the valve block, thereby bringing the end surface (sliding contact surface) of the pump block into contact with the end surface (sliding contact surface) of the valve block. The communication state between the plunger insertion hole and the communication hole was switched. That is, a so-called surface valve system has been adopted.
Such a surface valve method has an advantage that there is almost no dead space in the valve portion and even a very small amount of liquid can be discharged with high accuracy, but there is a possibility that the following problems may occur.

For example, when sending liquid to a remote position via a tube so that the robot can move the liquid discharge port at high speed, or when pumping discharge liquid like high viscosity liquid, the surface valve part In some cases, a high pressure (for example, a liquid pressure of about 100 atm) is applied to the case.
In other words, the pump block is pressed against the valve block side by a spring or the like, but if high pressure is applied to the surface valve part and the urging force of the spring is exceeded, the sliding surface of the pump block separates from the sliding surface of the valve block. This causes a problem that the liquid leaks.
On the other hand, if the pressing force (biasing force) is increased close to the permissible PV value and permissible load of each material of the valve block and the pump block in order to cope with the high pressure, wear of each sliding contact surface increases, and The torque required to rotate the pump block increases due to the frictional force of the face valve part, the efficiency must be reduced, and the motor must be increased, making the structure of the liquid ejection device more robust and heavy than necessary. There is a problem that must be done.

  An object of the present invention is to provide a liquid ejection apparatus that can be simplified in structure and easily reduced in size, and that can cope with a case where the hydraulic pressure is high.

The liquid ejection device of the present invention includes a cylinder block having three cylinder holes that are closed at one end and opened at the other end, and three plunger members that are inserted into the cylinder holes from the other end, Drive means for rotating the plunger member around the cylinder hole while reciprocating in the axial direction with respect to the cylinder hole. A suction port whose other end is opened on the outer surface of the cylinder block, and a discharge port whose one end is opened on the inner surface of each cylinder hole and whose other end is opened on the outer surface of the cylinder block. wherein the the inner circumferential surface of each cylinder bore, the intake-side opening and the discharge side openings through respectively with the suction port and the discharge port is formed respectively, wherein each flops The plunger member is opened on a side surface of the plunger member, and when the plunger member rotates, the suction side communication state communicated with the suction port, the port switching state not communicated with any of the suction port and the discharge port, the discharge port A side opening that can be sequentially switched to a discharge side communication state that is communicated with the port, and a port switching state that is not communicated with any of the discharge port and the suction port, and one end side that communicates with the side opening and that is closed on the cylinder hole. A liquid storage space opened at the end face of the opposing plunger member, and the suction side opening and the discharge side opening in each cylinder hole are connected to the side opening of one plunger member of the three plunger members. A state in which the side openings of the other two plunger members are not communicated with each other, and the three plunges A state in which the side opening of two plunger members of the members communicates with the suction side opening, and the side opening of the other plunger member communicates with the discharge side opening; and one plunger of the three plunger members A state in which the side opening of the member communicates with the suction side opening and the side opening of the other two plunger members communicates with the discharge side opening is formed so as to be switchable with the rotation of each plunger member, When the side opening of the plunger member is in the suction side communication state, the plunger member is rotated and moved away from one end side of the cylinder hole, and when the side opening of the plunger member is in the discharge side communication state, The plunger member is rotated and moved in a direction approaching one end side of the cylinder hole, and the side opening of the plunger member is in a port switching state. Sometimes, when the plunger member is rotated without moving in the axial direction and only the side opening of one plunger member is connected to the suction side opening, the amount of movement of the plunger member with respect to its rotation angle is increased. When it is moved in a direction away from one end side of the cylinder hole so as to be constant, and only the side opening of one plunger member communicates with the discharge side opening, the amount of movement of the plunger member relative to its own rotation angle is When the side surface openings of the two plunger members are communicated with the suction side opening, the plunger members are moved away from the one end side of the cylinder hole. The total amount of movement of each plunger member with respect to the rotation angle of each plunger member is the one plunger portion. When the side opening of the two plunger members is in communication with the discharge side opening, the amount of movement of the plunger member is set to be the same as the amount of movement of the plunger member when only the side opening of the plunger is in communication with the suction side opening. The plunger member is moved in a direction approaching one end side of the cylinder hole, and the total movement amount of each plunger member with respect to the rotation angle of the plunger member is such that only the side opening of the one plunger member communicates with the discharge side opening. It is set so that it may become the same as the movement amount of the plunger member in the case .

Here, since the plunger member is driven to rotate and advance / retreat with respect to the cylinder hole, a slight gap is provided between the side surface (outer peripheral surface) of the plunger member and the inner peripheral surface of the cylinder hole. This gap is set by the processing accuracy of the plunger member and the cylinder block. For example, when the cylinder block is made of ceramic and the plunger member is made of stainless steel, the clearance can be reduced to about 1 μm, particularly when the processing accuracy of the ceramic cylinder block is increased. If it is normal processing accuracy, it is about 5 μm. If the gap dimension can be narrowed to about 1 μm, even if the liquid has a low viscosity, the liquid can hardly be leaked through the gap portion, and the low-viscosity liquid can be accurately discharged. On the other hand, when the gap size is about 5 μm, the liquid may leak through the gap portion with a low-viscosity liquid. However, if the liquid has a relatively high viscosity such as an adhesive, the liquid leakage from the gap portion can be reduced. . Therefore, the gap size may be designed according to the type of liquid used.
Further, the plunger member only needs to have an opening formed on the side surface and a liquid storage space opened on the end surface facing the closed end surface of the cylinder hole. A D-cut plunger cut out in a plane parallel to the direction can be used. That is, a concave groove that continues from the axial end surface of the plunger member to the axial intermediate portion is formed on the side surface of the plunger member, and the liquid storage space may be formed by the concave groove. In this case, the side opening of the plunger member is formed by the opening of the concave groove (liquid storage space) on the side of the plunger member, and the end surface opening of the plunger member is formed by the opening of the concave groove on the plunger member end surface side.

In the present invention, when the plunger member is moved in a direction away from one end side of the cylinder in a state where the side opening of the plunger member inserted into the cylinder hole is in communication with the suction port, the liquid storage space of the plunger member and the plunger member The liquid metering space constituted by the space in the cylinder hole communicated with the liquid storage space via the end surface opening is enlarged. For this reason, the liquid is sucked into the liquid measuring space (the liquid storage space and the space in the cylinder hole communicating with the space) through the suction port and the side opening.
When the plunger member rotates and the side opening is not communicated with the suction port, the liquid is partitioned and measured in the liquid measuring space.
Further, when the plunger member is rotated and the plunger member is moved in a direction approaching one end side of the cylinder in a state where the side surface opening communicates with the discharge port, the liquid in the liquid measuring space is discharged through the discharge port.
Then, by repeating the above operations, liquid suction, metering, and discharge are repeated, and liquid is sequentially discharged.

According to the present invention as described above, the communication state between the discharge port and the suction port and the side opening of the plunger member is switched by rotating the plunger member inserted into the cylinder hole about the axis thereof. Since each port is opened on the inner peripheral surface of the cylinder hole, liquid pressure is applied to the outer peripheral surface of the plunger member. At this time, since the outer peripheral surface of the plunger member is guided by the inner peripheral surface of the cylinder hole, even if a high hydraulic pressure is applied to the plunger member, the pressure can be supported by the cylinder hole. A liquid discharge apparatus having a higher pressure resistance than the discharge apparatus can be obtained.
In the present invention, since the plunger member inserted into the cylinder hole is driven to rotate and advance / retreat, compared to the case of rotating the cylinder block in which the cylinder hole is formed as in the case of the conventional surface valve system. Thus, the driving force can be reduced, and the driving mechanism such as a motor can be reduced in size.

  According to the present invention as described above, the three plunger members are provided, the suction side opening and the discharge side opening are formed in each cylinder hole, and the side surface openings of the two plunger members can communicate with each opening at the same time. And by setting the cam surface to a predetermined shape, the movement amount of the plunger member when the side opening of one plunger member communicates with each opening and the side surface of the two plunger members Since the total amount of movement of the two plunger members when the opening communicates with each opening is always set to match, the liquid discharge amount and the suction amount when each plunger member is operated are set. , And can be made proportional to the rotation angle of each plunger member. That is, it is possible to make the discharge amount and the suction amount constant at every predetermined rotation angle of the plunger member, for example, every one degree. For this reason, the liquid can be continuously discharged at a constant discharge amount, and a non-pulsating continuous pump can be configured. Furthermore, by controlling the rotation speed, the discharge amount for a certain time can be increased or decreased, and the discharge amount can be easily controlled.

Here, the cylinder block is formed in a substantially cylindrical shape, the cylinder holes are formed at equal intervals on a concentric circle centered on the central axis of the cylinder block, and the discharge ports are formed along the central axis of the cylinder block. It is preferable to include a single discharge hole and a communication hole that communicates the discharge hole with each cylinder hole.
According to such a configuration, since it is not necessary to form a plurality of discharge holes corresponding to each cylinder hole, the configuration of the cylinder block can be simplified and the configuration can be made compact, so that the liquid discharge device can be easily reduced in size. Can be

In addition, the side opening of the plunger member is formed at a position a predetermined distance away from the end of the plunger member on the side of the plunger member, and the side of the plunger member is left on each plunger end side of the side opening. preferable.
According to such a configuration, the side opening formed on the side surface of the plunger member is formed at an intermediate portion between both axial ends of the plunger on the side surface of the plunger member. For this reason, even when a high hydraulic pressure is applied to the plunger member from the discharge port side or the like, and the side surface opening side of the plunger member is pressed against the inner peripheral surface of the cylinder hole, the side surface portions that exist on both axial sides of the side surface opening of the plunger member Since it contacts the cylinder hole, the hydraulic pressure can be supported in a well-balanced manner. For this reason, compared with the case of using a so-called D-cut type plunger member in which a side end portion of the plunger member is cut out to form a recess for sucking liquid, the plunger member is axially moved even when a high pressure is applied. On the other hand, since the plunger member can be smoothly advanced and retracted in the axial direction without being inclined, it is possible to provide a liquid discharge apparatus with high pressure resistance.

Further, the cylinder block is arranged in a container capable of storing a liquid for discharge, and configured to be able to collect the liquid in the container when the liquid leaks between the cylinder hole and the plunger member. preferable.
According to such a configuration, it is not necessary to arrange a sealing material for preventing liquid leakage, so that assembly work and maintenance work can be easily performed.

Further, the driving means includes a motor, a cam rotated by the motor, and a cam follower connected to each plunger member, and the cam is a cam surface having a predetermined shape formed on an end surface thereof. And a gear provided on the rotation center shaft portion and projecting from the cam surface. One end of the cam follower is coupled to each plunger member so as to be reciprocally driven and rotatable, and the other end A cam follower main body having a substantially hemispherical recess formed on the other end side end surface is formed on the side, and a gear that can mesh with the gear of the cam and advance and retract in the axial direction with respect to the gear. A ball disposed and capable of contacting the cam surface;
The friction coefficient between the ball and the recess is set smaller than the friction coefficient between the cam surface and the ball, and when the cam is driven to rotate by the motor, the cam follower body is rotated by meshing with the cam gear. In addition, it is preferable that the cam surface in contact with the ball is rotationally moved to advance and retract in the axial direction according to the shape of the cam surface, and the plunger member is rotated and advanced and retracted integrally with the cam follower body.

In the present invention as described above, the cam follower that abuts the cam surface is composed of a ball and a plunger member having a concave portion for holding the ball, so that the diameter of the liquid ejection device can be made smaller than when a conventional roller is used. This can reduce the size of the liquid ejection device. In other words, when a roller is used, a roller shaft must protrude from the plunger member arranged in the valve member so as to be able to advance and retreat in the axial direction, and the roller must be arranged rotatably on this roller shaft. The diameter of the moving locus of the roller revolving along the cam surface is also increased, and the diameter of the end face cam must be increased corresponding to the moving locus of the roller.
On the other hand, in the present invention, the ball only has to be disposed in the concave portion of the plunger member, and there is no portion protruding from the plunger member to the outer peripheral side. And can be easily downsized.

  Further, in the present invention, the friction coefficient between the ball and the concave portion that holds the ball is set lower than the friction coefficient between the cam surface and the ball. Even if this force is applied, the force is absorbed by sliding of the concave portion of the plunger member and the ball. For this reason, a side slip etc. do not generate | occur | produce between a cam surface and a ball | bowl, but a ball can be rolled without slipping with respect to a cam surface. Therefore, it is not necessary to form the cam surface with oil-impregnated resin in consideration of friction as in the prior art, and it can be formed with a hard member such as metal, and the ball can also be formed with a hard member, so the stroke amount error of the plunger member And the liquid discharge accuracy can be improved.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a front view of a liquid ejection device (dispenser, pump) 1 according to an embodiment of the present invention.
The liquid ejection device 1 includes a driving unit 2, a case body 3, and a container 4. As the driving means 2, various driving devices such as a servo motor and a stepping motor can be used. In the present embodiment, the driving means 2 includes a servo motor 2A and a speed reducer 2B.
The case body 3 includes a main tube 11, a connecting tube 12 that connects the main tube 11 and the driving means 2, and a connecting tube 13 that connects the main tube 11 and the container 4.

  The main cylinder 11 and the connecting cylinders 12 and 13 are each formed in a substantially prismatic shape. As shown in FIG. 2, the main cylinder 11 is inserted into the screw holes provided at the four corners of the connecting cylinders 12 and 13, respectively. Are connected by screwing bolts 14. The servo motor 2A and the speed reducer 2B are fixed to the connecting cylinder 12 with bolts (not shown), and the container 4 is fixed to the connecting cylinder 13 with bolts (not shown).

As shown in FIG. 3, the container 4 includes an upper lid member 4A connected to the connecting cylinder 13, a container body 4C fixed to the upper lid member 4A with bolts 4B, and a lower lid member 4D that closes the lower end opening of the container body 4C. And is configured.
Note that the structure of the container 4 is not limited to that described in the present embodiment, and may be of another structure, for example, one in which the container body 4C and the lower lid member 4D are integrated.

A cylinder block 30 is disposed in the container 4.
On the other hand, through holes 11 </ b> A to 13 </ b> A having a substantially circular cross section are formed in the main cylinder 11 and the connection cylinders 12 and 13. In these through holes 11A and 12A, a cam follower guide block 60 and an end face cam 20 are arranged in this order from the container 4 side.

The cylinder block 30 is formed of a hard material such as alumina ceramic, and has a substantially cylindrical shape as shown in FIG.
The cylinder block 30 has three cylinder holes 31 that penetrate in the axial direction, three bolt insertion holes 32 that also penetrate in the axial direction, and a discharge hole 33 </ b> A formed in the central axis of the cylinder block 30. Is formed. The discharge hole 33 </ b> A is open to the end surface on the lower lid member 4 </ b> D side of the cylinder block 30 and is formed to have a length up to an intermediate portion in the axial direction of the cylinder block 30 so as not to penetrate the cylinder block 30 in the axial direction. Yes.

Further, as shown in FIG. 5, each cylinder hole 31 is concentrically arranged with respect to the center axis of the cylinder block 30, and the position of the center axis of each cylinder hole 31 with respect to the center axis of the cylinder block 30 is 120. They are arranged at regular intervals.
The discharge hole 33 </ b> A and each cylinder hole 31 communicate with each other via three communication holes 33 </ b> B provided corresponding to each cylinder hole 31. And the discharge port 33 of each cylinder hole 31 is comprised by this communication hole 33B and the discharge hole 33A. That is, three discharge ports 33 are provided corresponding to the three cylinder holes 31, and the discharge holes 33 </ b> A are shared by the discharge ports 33. Accordingly, the discharge port 33 has one end side, that is, the opening end of the discharge hole 33A is opened on the inner peripheral surface of each cylinder hole 31, and the other end side, that is, the opening end of the discharge hole 33A is the outer surface of the cylinder block 30 (lower lid member 4D). Side surface).

The cylinder block 30 is formed with a total of three suction ports 35, one for each cylinder hole 31, which communicates the cylinder hole 31 with the side surface (outer surface) of the cylinder block 30. That is, the suction port 35 has one end opened to the inner peripheral surface of each cylinder hole 31 and the other end opened to the outer surface (side surface) of the cylinder block 30.
The opening position formed on the side surface of the cylinder block 30 of the suction port 35 is adjusted to the height position exposed to the internal space of the container 4, particularly the lowest part of the space in which the liquid is stored, as shown in FIG. In the position. Further, the bottom surface of the container 4 is inclined so that the liquid flows toward the central portion where the cylinder block 30 is disposed. For this reason, it is designed to flow into the suction port 35 even when the amount of liquid in the container 4 decreases.

Each opening of the discharge port 33 and the suction port 35 formed in the cylinder hole 31 is disposed so as to face the center axis of the cylinder hole 31. Further, as shown in FIGS. 4 and 5, a discharge side opening 34 </ b> A communicating with the discharge port 33 and a suction side opening 35 </ b> A communicating with the suction port 35 are formed on the inner peripheral surface of the cylinder hole 31, respectively.
Here, the opening 42 of the plunger member 40 and each of the openings 34A and 35A communicate with each other within a predetermined rotation angle range even if the plunger member 40 rotates with respect to the cylinder hole 31. The size and the formation position are such that the maintained state can be maintained. For this reason, each of the openings 34A and 35A may be a circular opening, but is preferably formed in an elliptical shape in which the major axis direction is the rotation direction of the plunger.
Further, the communication hole 33B is configured such that the suction side opening 35A side has a large diameter, and the discharge hole 33A side has a small diameter through a diameter reduction portion in the middle.

As shown in FIG. 3, one end surface (lower end surface) of the cylinder block 30 is in contact with the lower lid member 4D via a fluororesin sheet 36. The other end face (upper end face) of the cylinder block 30 is also in contact with the support plate 37 via the fluororesin sheet 36.
The bolt 38 inserted through the lower lid member 4 </ b> D, the bolt insertion hole 32 of the cylinder block 30, and the support plate 37 is screwed into one end of the support rod 39. The other end of the support rod 39 is fixed to the upper lid member 4A by a bolt inserted through the upper lid member 4A.
Therefore, the cylinder block 30 is suspended and supported via the three support rods 39 fixed to the upper lid member 4A.

On the other hand, a plunger member 40 is inserted into each cylinder hole 31. As shown in FIG. 4, the plunger member 40 is formed in a columnar shape (a rod having a circular cross section). Further, the plunger member 40 opens to a lower end surface thereof (a surface facing the lower lid member 4D that closes the cylinder hole 31 and the fluororesin sheet 36) and extends to an intermediate portion in the axial direction of the plunger member 40. The liquid storage space 41 is provided.
The liquid storage space 41 is also communicated with an opening 42 formed on the side surface of the plunger member 40 at a position away from the end surface of the plunger member 40 by a predetermined dimension. The height of the opening 42 is formed larger than the height of the hole of the suction port 35. For this reason, when the plunger member 40 is moved up and down in the cylinder hole 31, the communication state between the opening 42 and the suction port 35 can be maintained.

  The plunger member 40 is connected to the connecting rod 44 via the flexible coupling 43. The flexible coupling 43 is formed of a synthetic resin or the like and includes a thin portion formed by cutting or the like, so that the center of the connecting rod 44 can be obtained even if the angle between the central axes of the plunger member 40 and the connecting rod 44 is slightly inclined. The rotational force about the shaft as a rotation center can be transmitted to the plunger member 40 via the flexible coupling 43.

The upper end side of each connecting rod 44 is inserted through a bush 45 fitted into a hole formed in the upper lid member 4A, and is extended to the through hole 13A portion.
As shown in FIG. 6, a hub 47 constituting an Oldham joint 46 is fixed to the upper end of each connecting rod 44 using a pin 46A or the like.

Each hub 47 is guided by a support plate 50 bolted to a cam follower guide block 60 so as to be rotatable and axially movable.
A coil spring 48 as an urging means is interposed between the hub 47 and the bush 45, and urges the hub 47, that is, the connecting rod 44 toward the cam follower guide block 60 side. Specifically, the coil spring 48 is interposed between the bush 45 and the spring receiver 48 </ b> A, and a ball bearing 49 is disposed between the spring receiver 48 </ b> A and the hub 47. Since the bush 45 is fixed to the container 4, the biasing force of the coil spring 48 is applied to the hub 47 via the spring receiver 48 </ b> A and the ball bearing 49, and the hub 47, that is, the connecting rod 44 is biased toward the cam follower guide block 60. Yes. The hub 47 and the connecting rod 44 not only move forward and backward in the axial direction, but also rotate around the central axis, but since the ball bearing 49 is interposed, the hub 47 and the connecting rod 44 are smoothly urged by the coil spring 48. Can be rotated.

The cam follower guide block 60 is made of a synthetic resin material such as oil-impregnated POM (polyacetal) or a metal material such as stainless steel, and has a substantially cylindrical shape as shown in FIG. The cam follower guide block 60 has a through hole 61 formed in the central axis portion, and a through hole 62 as three guide holes formed around the through hole 61.
The through-hole 61 has a small diameter portion 61A on the container 4 side and a large diameter portion 61B on the end face cam 20 side. The small-diameter portion 61 </ b> A has a sectional radius from the central axis of the cam follower guide block 60 that is shorter than the distance from the central axis to each through hole 62, and is partitioned from the through hole 62. On the other hand, the large-diameter portion 61 </ b> B has a cross-sectional radius from the central axis of the cam follower guide block 60 that is longer than the distance from the central axis to each through hole 62 and communicates with the through hole 62.

  A cylindrical ball holding member 70 is inserted into each through hole 62 of the cam follower guide block 60. The ball holding member 70 is inserted in each through hole 62 so as to advance and retreat in the axial direction. A substantially hemispherical recess 71 is formed on the end surface of the ball holding member 70 on the end cam 20 side, and a ball 75 is accommodated in the recess 71. Of the outer peripheral surface of the ball holding member 70, about half of the end face cam 20 side (from the end face on the end face cam 20 side in the axial direction to the middle part), teeth 72 are formed to form a gear.

On the other hand, as shown in FIG. 6, a hub 73 constituting the Oldham joint 46 is attached to the end of the ball holding member 70 on the cylinder block 30 side using pins 74.
In the Oldham joint 46, the hub 73 is slightly movable in the axial direction of the pin 74 with respect to the ball holding member 70. Further, the projections 47A and 47B formed on the hub 47 are fitted into the concave grooves 73A and 73B formed on the hub 73, and the hub 47 slides in a direction perpendicular to the axial direction of the pin 74 with respect to the hub 73. It can be moved. Therefore, the Oldham joint 46 is configured by the hub 47, the hub 73, and the pin 74, and the Oldham joint 46 is configured so that rotation can be transmitted even if the connecting rod 44 and the ball holding member 70 are misaligned.

  As shown in FIG. 6, the two projecting portions 47A and 47B formed on the end surface of the hub 47 have different width dimensions, and the two concave grooves 73A and 73B formed on the end surface of the hub 73 are also different in width from each other. The dimensions are different. Therefore, the hub 47 and the hub 73 are configured to be connected only in a direction in which the protrusion 47A is fitted in the groove 73A and the protrusion 47B is fitted in the groove 73B. Thereby, when assembling the liquid ejection apparatus 1, it is possible to easily assemble without making a mistake in the direction of the plunger member 40, that is, the direction of the opening 42.

As shown in FIG. 2, the end face cam 20 is disposed on the servo motor 2 </ b> A side of the cam follower guide block 60.
The end face cam 20 includes a substantially cylindrical cam main body 23 having a through-hole formed in the central shaft portion, and a gear shaft member 24 fitted in the through-hole of the cam main body 23. Are arranged via ball bearings 21. For this reason, the end face cam 20 is supported so as to be rotatable about its central axis and not to be movable in the axial direction.

The end face cam 20 is connected to the output shaft 2 </ b> C via an Oldham joint 22. The Oldham joint 22 is a disc-shaped hub having a cylindrical hub 22A fixed to the output shaft 2C, and a protrusion that is slidably fitted in a groove formed on the end surface of the hub 22A in the extending direction. The slider 22B is provided. A concave groove is formed on the other plane opposite to the plane on which the protruding portion of the slider 22B is formed, and the extending direction of the protruding portion and the concave groove is configured to be orthogonal to each other.
A protrusion 20B formed on the end face of the end face cam 20 is fitted in the groove of the slider 22B so as to be slidable in the extending direction, and the axis between the output shaft 2C and the rotation shaft of the end face cam 20 is shifted. Even so, the rotation can be transmitted.

The cam body 23 and the gear shaft member 24 of the end face cam 20 are integrated by a pin 25 provided so as to penetrate each member, and the cam body 23 and the gear shaft member 24 rotate integrally. The gear shaft member 24 is not movable in the axial direction with respect to the cam body 23.
Here, the cam body 23 has a projection 20B that fits into the groove of the slider 22B on one end surface, and a cam surface 20A on the other end surface, forming a three-dimensional cam. The cam surface 20A is formed to be a cam diagram as shown in FIG.

  In this embodiment, the cam follower body is configured by the ball holding member 70 and the connecting rod 44, and the cam follower is configured by the cam follower body, that is, the ball holding member 70 and the connecting rod 44, and the ball 75.

The gear shaft member 24 has an end portion on the cam follower guide block 60 side as a small diameter portion 24 </ b> A, and the small diameter portion 24 </ b> A is rotatably fitted in the small diameter portion 61 </ b> A of the through hole 61 of the cam follower guide block 60.
Further, teeth 27 are formed on the outer peripheral surface of the portion protruding from the cam surface 20A of the gear shaft member 24 to form a gear. The teeth 27 are meshed with the teeth 72 of the ball holding member 70.

Further, since the ball holding member 70 is biased toward the cam surface 20A by the coil spring 48, the ball 75 always rolls while being in contact with the cam surface 20A.
Therefore, when the motor 2A is driven and the output shaft 2C is rotated, the end face cam 20 is rotated, and the rotation is transmitted to the three ball holding members 70 via the gear shaft member 24, and the Oldham joint 46 is further rotated. The three plunger members 40 can be rotated about the center axis of the rotation through the connecting rod 44 and the flexible coupling 43.
At the same time, as the end face cam 20 rotates, the ball 75 and the ball holding member 70 advance and retreat in the axial direction along the shape of the cam surface 20A. The advance / retreat of the ball holding member 70 is transmitted to the plunger member 40 via the Oldham coupling 46, the connecting rod 44, and the flexible coupling 43.

Here, the material of each ball holding member 70, the ball 75, and the end face cam 20, and the coating treatment so that the friction coefficient between the ball holding member 70 and the ball 75 is lower than the friction coefficient between the ball 75 and the cam surface 20 </ b> A. Presence or absence, coating method, etc. are set.
Specifically, the ball 75 is a hard ball made of a superhard alloy such as tungsten carbide. The end face cam 20 is also made of a hardened and polished metal such as carbon tool steel, and the cam face 20A is hard.
On the other hand, each ball holding member 70 can be made of resin or the like. Here, each ball holding member 70 is usually made of a soft resin material compared to the ball 75, but the surface of the ball holding member 70 may have the same hardness as the ball 75 by DLC coating or the like. . In short, each material or the like may be selected so that the coefficient of friction with the ball 75 is lower on each ball holding member 70 side than on the cam surface 20A. Each ball holding member 70 is soft compared to the ball 75, and the displacement of the cam surface 20A must be transmitted to the plunger 80 via the ball 75 and each ball holding member 70. Therefore, the strength that does not cause deformation by such contact is ensured.

Next, the effect | action of this embodiment is demonstrated with reference to FIGS.
A liquid is supplied into the container 4 before operating the liquid ejection apparatus 1 of the present embodiment. For example, the liquid may be supplied by providing the upper lid member 4A with a liquid supply port or by removing the container body 4C from the upper lid member 4A. The container 4 may be supplied with liquid for a certain period of time and replenished at regular time intervals. Alternatively, the liquid may be continuously supplied from the liquid supply port to enter the container 4. You may make it accumulate temporarily and discharge.

[Explanation of operation of plunger member]
The operation of each plunger member 40 is as follows.
When the motor 2A is driven in a state where the liquid is supplied to the container 4, the rotation of the output shaft 2C is transmitted to each ball holding member 70 via the cam body 23 and the gear shaft member 24 of the end face cam 20. Further, since the ball holding member 70 is urged toward the cam surface 20A by the coil spring 48, the ball 75 held by the ball holding member 70 remains in contact with the cam surface 20A and the axial direction of the cam surface 20A. Advances and retreats along the displacement. At this time, since the friction coefficient between the ball 75 and the recess 71 is smaller than the friction coefficient between the ball 75 and the cam surface 20A, the ball 75 rolls against the cam surface 20A and slides against the recess 71. Will rotate.

  The rotation and advance / retreat of the ball holding member 70 is transmitted to the plunger member 40 via the Oldham joint 46, the connecting rod 44, and the flexible coupling 43, and the plunger member 40 moves into the cylinder hole 31 of the cylinder block 30 according to the cam surface 20A. Rotate while moving forward and backward in the axial direction.

  The plunger member 40 is advanced and retracted by setting the shape of the cam surface 20A to an appropriate shape, so that the end face cam is located at a position where the opening 42 of the plunger member 40 communicates with the opening 35A on the suction port 35 side of the cylinder block 30. It is moved in the direction away from the 20 side, that is, the suction port 35 side (upward in FIG. 3). Due to the movement of the plunger member 40, a negative pressure is generated in the liquid storage space 41 and a space (liquid metering space) formed in the cylinder hole 31 through which the liquid storage space 41 communicates, and this negative pressure causes the suction port 35, The liquid to be transferred is sucked into the liquid metering space through the opening 35A.

  At the point where the movement of the plunger member 40 toward the end face cam 20 side (rear end side) is completed, the opening 42 moves away from the position of the opening 35A and moves along the inner peripheral surface of the cylinder hole 31. In the middle of this movement, the cam surface 20A has a flat shape with no axial displacement. Therefore, the plunger member 40 does not move forward and backward in the axial direction, and remains in the position as it is toward the opening 34A. And rotate. During this rotational movement, the liquid storage space 41 is not communicated with either the suction port 35 or the discharge port 33, so that the liquid metering space (the liquid storage space 41 and the space in the cylinder hole 31 communicating therewith) Since the volume is constant and the volume of the liquid inside is also constant, the liquid is measured with high accuracy.

  When the opening 42 comes to a position communicating with the opening 34A on the discharge port 33 side, the ball 75 and the ball holding member 70 are moved to the cylinder block 30 side (front end side) by the action of the cam surface 20A. The plunger member 40 is similarly moved to the distal end side through the connecting rod 44 and the like, and the sucked liquid is pushed out from the liquid storage space 41 according to the amount of movement, and through the communication hole 33B and the discharge hole 33A. To discharge.

  The liquid discharging operation by the plunger member 40 is performed while the opening 42 communicates with the arc-shaped opening 34A, and is completed when the opening 42 is removed from the opening 34A, and the opening 42 is removed from the opening 34A. When the position is reached, the movement of the plunger member 40 in the axial direction is stopped. The stopped state of the plunger member 40 is maintained until the opening 42 comes to the position of the opening 35A on the suction port 35 side again by the rotation of the end face cam 20 and the plunger member 40.

Thus, when the opening 42 comes again to the opening 35A side of the suction port 35, the plunger surface 40 is moved again to the end face cam 20 side by the action of the cam surface 20A, and the suction for sucking liquid from the suction port 35 is performed. The operation moves to the operation, and thereafter the same operation is repeated, and by one rotation of the plunger member 40 inserted into one cylinder hole 31, the liquid suction and discharge operations are performed one cycle at a time.
At this time, as the plunger member 40 rotates, the opening 42, that is, the liquid storage space 41, communicates with the suction side opening 35 </ b> A (suction port open state) and communicates with the discharge side opening 34 </ b> A (discharge port open state). And a state in which neither of the openings 34A and 35A communicates (suction / discharge port closed state) is sequentially repeated. That is, the same operation as that in which a valve is provided at each port and the valve is switched can be obtained.

The suction and discharge operations associated with the advance and retreat of the plunger member 40 are performed in the same manner for each plunger member 40. As can be seen from FIGS. 5 and 9 to 11, the two adjacent plunger members 40 perform the suction or discharge operation. Since the two can communicate with the opening 34A and the opening 35A at the same time, the liquid sucked into each liquid storage space 41 or discharged from the liquid storage space 41 is continuously sucked or discharged. And, as will be described later, a constant flow rate is maintained.
In addition, by appropriately setting the shape of the cam surface 20A, the total flow rate of the liquid sucked into or discharged from each liquid storage space 41 is always constant. Can be discharged.

[Description of Operation of Three Plunger Members 40]
Hereinafter, the operation of each plunger member 40 will be described in more detail. 9-11, the three plunger members 40 are demonstrated as the 1st plunger member 40A, the 2nd plunger member 40B, and the 3rd plunger member 40C, respectively.
The cam surface 20A has a cam shape corresponding to the cam diagram shown in FIG. In the y-axis of this cam diagram, the cam surface 20A closest to the cylinder block 30 side is the lowest cam position (y = 0), and the farthest part is the highest cam position (in this embodiment, for example, y = 8 .4mm). On the other hand, in the x-axis, the state where the ball 75 is in contact with the lowest cam position (y = 0) is 0 °, and the rotation angle of the end face cam 20 from that position, that is, the relative rotation angle of the cam surface 20A with respect to the ball 75. Is represented. In the cam diagram, the movement locus of the center position of the ball 75 is also described.

  As described in this cam diagram, the cam surface 20A remains in the lowest position (y = 0) when the rotation angle of the end face cam 20 is 0 ° to 16 °, and the ball 75 and the plunger member 40 are It does not move in the axial direction of the plunger member 40. The cam surface 20A from 16 ° to 44 ° is set so that the ball 75 and the plunger member 40 move to the end cam 20 side (upper side) by a uniform acceleration motion. Further, the cam surface 20A from 44 ° to 136 ° is set so that the ball 75 and the plunger member 40 move toward the end face cam 20 by a constant speed motion. Further, the cam surface 20A from 136 ° to 164 ° is set so that the ball 75 and the plunger member 40 move toward the end face cam 20 by a uniform acceleration motion. Further, from 164 ° to 196 °, the cam surface 20A remains at the highest cam position, and the ball 75 and the plunger member 40 do not move in the axial direction of the plunger member 40.

  The cam surface 20A from 196 ° to 224 ° is set so that the ball 75 and the plunger member 40 move to the lower lid member 4D side (downward side) by a uniform acceleration motion. Furthermore, the cam surface 20A from 224 ° to 316 ° is set so that the ball 75 and the plunger member 40 move to the lower lid member 4D side at a constant speed. Further, the cam surface 20A from 316 ° to 344 ° is set so that the ball 75 and the plunger member 40 move to the lower lid member 4D side by a uniform acceleration motion. Further, from 344 ° to 360 °, the cam surface 20A remains in the lowest position (y = 0), and the ball 75 and the plunger member 40 do not move in the axial direction of the plunger member 40.

Accordingly, when the end face cam 20 rotates, the plunger members 40 rotate about the central axis through the gear shaft member 24, the ball holding member 70, and the like, and the balls 75 come into contact with the cam surface 20A. Thus, each plunger member 40 moves forward and backward in the axial direction. At this time, the three plunger members 40 (40A, 40B, 40C) operate as follows.
Each plunger member 40 has a 120 ° phase shift with respect to the cam surface 20A because the circumferential interval along the cam surface 20A is 120 °. That is, when one plunger member 40 (first plunger member 40A) is at the 0 degree position of the cam surface 20A, the other two plunger members 40 (second plunger member 40B, third plunger member 40C) The cam surface 20A is positioned at 120 degrees and 240 degrees, respectively.

  As shown in FIGS. 9A and 9B, when the rotation angle of the end face cam 20 is 0 ° to 16 °, the cam surface 20A remains in the lowest position (y = 0), and the first plunger member 40A does not move in the axial direction of the plunger member 40. The opening 42 of the first plunger member 40A is designed not to communicate with any of the openings 34A and 35A.

On the other hand, the second plunger member 40B is moved from 120 ° to 136 ° of the cam surface 20A, and the end 42 is connected to the opening 35A on the suction port 35 side and is moved toward the end face cam 20 by constant speed movement. Moved.
The third plunger member 40C moves from the 240 ° to 256 ° position of the cam surface 20A, and the lower lid member 4D side (lower end) is moved at a constant speed with the opening 42 communicating with the opening 34A on the discharge port 33 side. Side).
Therefore, in this state, the second plunger member 40B performs an operation of sucking the liquid into the liquid storage space 41, the third plunger member 40C performs an operation of discharging the liquid from the liquid storage space 41, and the first plunger member 40A. Neither sucks nor discharges liquid.

When the first plunger member 40A is moved from the 16 ° position of the cam surface 20A shown in FIG. 9B to the 44 ° position shown in FIG. 9C, the first plunger member 40A has an opening 35A. In the state where the opening 42 is communicated with each other, and is moved to the end face cam 20 side by equal acceleration motion.
At this time, the second plunger member 40B moves from a position of 136 ° on the cam surface 20A to a position of 164 °, and moves toward the end face cam 20 in a state where the opening 42 communicates with the opening 35A and with a constant acceleration motion.
On the other hand, the third plunger member 40C moves from a position of 256 ° on the cam surface 20A to a position of 264 °, and moves to the lower lid member 4D side in a state where the opening 42 is in communication with the opening 34A and at a constant speed.

Accordingly, both the first plunger member 40A and the second plunger member 40B move to the end face cam 20 side, and are sucked into the space formed in the cylinder hole 31 where each liquid storage space 41 and the liquid storage space 41 communicate with each other. Liquid is sucked through the port 35 and the opening 35A.
On the other hand, since the third plunger member 40C moves to the lower lid member 4D side, the liquid is discharged from the discharge port 33 from the space in the liquid storage space 41 and the cylinder hole 31 of the third plunger member 40C through the opening 34A. Is done.
At this time, the constant velocity region of the cam surface 20A is such that the liquid discharge amount by the third plunger member 40C with respect to the rotation angle of the end face cam 20 coincides with the sum of the liquid suction amounts by the first plunger member 40A and the second plunger member 40B. And the constant acceleration area is set.

When the first plunger member 40A is moved from the position of 44 ° of the cam surface 20A shown in FIG. 9C to the position of 136 ° shown in FIG. 10D, the first plunger member 40A has an opening 35A. In the state where the opening 42 is communicated to the end face cam 20, the end face cam 20 is moved at a constant speed.
At this time, since the second plunger member 40B moves from the 164 ° position on the cam surface 20A to the 256 ° position, the second plunger member 40B has the opening 42 communicating with both the discharge port 33 and the suction port 35. Rotate in a state where it is not, and then move to the lower lid member 4D side with the opening 42 communicating with the opening 34A to perform a liquid discharge operation.
On the other hand, since the third plunger member 40C moves from a position of 284 ° on the cam surface 20A to a position of 376 ° (that is, 16 °), the opening of the third plunger member 40C is changed to the opening 34A on the discharge port 33 side. After rotating in a connected state and performing a liquid discharging operation, the opening 42 subsequently moves to a state where it is not connected to the openings 34A and 35A.

  Therefore, between FIG. 9C and FIG. 10D, only the first plunger member 40A communicates with the suction port 35 to perform the liquid suction operation. At this time, the axial movement amount of the first plunger member 40A with respect to the rotation angle of the end face cam 20 is constant. Therefore, a certain amount of liquid is sucked into the liquid storage space 41 and the cylinder hole 31 with respect to the rotation angle of the end face cam 20, that is, the output shaft 2 </ b> C. This suction amount is the same as the amount when the liquid is sucked by both the first plunger member 40A and the second plunger member 40B, and a constant amount of liquid is continuously sucked from the container 4. The

When the first plunger member 40A has moved from the 136 ° position of the cam surface 20A shown in FIG. 10D to the 164 ° position shown in FIG. 10E, the first plunger member 40A has an opening 35A. In the state where the opening 42 is communicated with each other, and is moved to the end face cam 20 side by equal acceleration motion.
Similarly, since the third plunger member 40C moves from the position of 16 ° to the position of 44 °, the third plunger member 40C is moved to the end cam 20 side in a state where the opening 42 is communicated with the opening 35A and in a uniform acceleration motion.
Here, each cam surface 20A in this portion is set to have a uniform acceleration motion, and the movement amount of the third plunger member 40C increases with respect to the rotation angle between 16 ° and 44 °. The movement amount of the first plunger member 40A decreases between 136 ° and 164 °.
Then, the cam surface 20A is set so that the total amount of movement of the plunger members 40A and 40C always coincides with the case where the plunger member 40 moves from a position of 44 ° to 136 °. For this reason, even when each opening 42 communicates with the suction port 35 via the opening 35A, the total amount of movement of the two plunger members 40A and 40C is constant, so the suction amount with respect to the rotation angle is the plunger member. This is the same as when 40 is moving at a constant velocity, and a constant amount of inhalation is continued.

  On the other hand, since the second plunger member 40B moves from a position of 256 ° to a position of 284 °, the lower lid member 4D side is in a state where the opening 42 is in communication with the discharge port 33 through the opening 34A and is moved at a constant speed. Moved to. With this movement, the liquid sucked into the liquid storage space 41 and the cylinder hole 31 of the second plunger member 40B is discharged through the opening 34A and the discharge port 33. In the present embodiment, a connecting tool in which a through hole communicating with the discharge hole 33A is attached to the lower lid member 4D, and a discharge tube is connected to a screw of this connecting tool, and the tip of the tube is not shown. The liquid is discharged from the nozzle.

When the first plunger member 40A is moved from the 164 ° position of the cam surface 20A shown in FIG. 10 (E) to the 196 ° position shown in FIG. 10 (F), the opening 42 of the first plunger member 40A is Then, the opening is disengaged from the opening 35A and is not in communication with any of the openings 34A, 35A.
Accordingly, since the liquid storage space 41 of the first plunger member 40A is not communicated with either the discharge port 33 or the suction port 35, the ports 33 and 35 (valves) are closed.

Since the second plunger member 40B continues to move from the position of 284 ° to the position of 316 °, the opening 42 is in communication with the discharge port 33 through the opening 34A and is moved toward the lower lid member 4D side at a constant speed. It is moved and a certain amount of liquid is continuously discharged.
The third plunger member 40C is moved from a position of 44 ° to a position of 76 °, and is moved toward the end face cam 20 in a state where the opening 42 is communicated with the opening 35A and at a constant speed. That is, only the third plunger member 40C communicates with the suction port 35 side, and as described above, the liquid is sucked into the liquid storage space 41 and the cylinder hole 31 of the third plunger member 40C.

When the first plunger member 40A is moved from the 196 ° position of the cam surface 20A shown in FIG. 10 (F) to the 224 ° position shown in FIG. 11 (G), the opening 42 of the first plunger member 40A is While moving to the opening 34A, it moves to the lower lid member 4D side by a uniform acceleration motion.
Similarly, the second plunger member 40B moves from a position of 316 ° to a position of 344 °, and the opening 42 of the second plunger member 40B communicates with the opening 34A while moving toward the lower lid member 4D with a constant acceleration motion. Moving.
Therefore, the volume of the space defined by the liquid storage space 41 of each plunger member 40A, 40B and the cylinder hole 31 communicating therewith is reduced, and the liquid sucked into the space is discharged through the opening 34A. 33 is discharged.

,
Here, the cam surface 20A of this portion is set to have a uniform acceleration motion, and the movement amount of the first plunger member 40A is increased with respect to the rotation angle between 196 ° and 224 °. The movement amount of the second plunger member 40B decreases between 316 ° and 344 °. Then, the cam surface 20A is set so that the total amount of movement of the first and second plunger members 40A, 40B always coincides with the case where the plunger member 40 is moving from 224 ° to 316 °. Has been. For this reason, even when the openings 42 of the two plunger members 40A and 40B are communicated with the discharge port 33, the total amount of movement of the two plunger members 40A and 40B is constant. Is the same as when the plunger member 40 is moving at a constant speed, and a certain amount of discharge is continued.

  On the other hand, the third plunger member 40C moves from the 76 ° position to the 104 ° position. For this reason, as described above, while moving alone to the suction port 35, it moves toward the end face cam 20 and continues the liquid suction operation.

  When the first plunger member 40A is moved from the 224 ° position of the cam surface 20A shown in FIG. 11G to the 316 ° position shown in FIG. 11H, the opening 42 of the first plunger member 40A is While moving to the opening 34A, it moves to the lower lid member 4D side by a constant velocity motion. During this time, only the opening 42 of the first plunger member 40A communicates with the discharge port 33, and the first plunger member 40A moves at a constant speed, so that the liquid discharge amount with respect to the rotation angle of the end face cam 20 is constant. Maintained.

The second plunger member 40B moves from a position of 344 ° to a position of 76 °, and the third plunger member 40C moves from a position of 104 ° to a position of 196 °.
Here, until the second plunger member 40B reaches the position of 344 ° to 16 °, the opening 42 does not communicate with any of the ports 33 and 35, and the so-called valve is closed. At this time, since the third plunger member 40C moves from 104 ° to 136 °, the third plunger member 40C moves to the end face cam 20 side by a constant velocity motion, and performs the liquid suction operation only by the third plunger member 40C.
Furthermore, while the second plunger member 40B is moved from the position of 16 ° to 44 ° and the third plunger member 40C is moved from the position of 136 ° to 164 °, the plunger members 40B and 40C are It moves to the end face cam 20 side by a uniform acceleration motion, and a constant amount of liquid suction is continued by the cooperation of the plunger members 40B and 40C.
Subsequently, while the second plunger member 40B is moved from 44 ° to 76 ° and the third plunger member 40C is moved from 164 ° to 196 °, only the second plunger member 40B is moved as described above. The third plunger member 40C is in a state in which the ports 33 and 35 (valves) are closed by communicating with the suction port 35 and performing a liquid suction operation.

When the first plunger member 40A is moved from the 316 ° position of the cam surface 20A shown in FIG. 11 (H) to the 344 ° position shown in FIG. 11 (I), the opening 42 of the first plunger member 40A is While moving to the opening 34A, it moves to the lower lid member 4D side by a uniform acceleration motion.
During this time, since the third plunger member 40C also moves from 196 ° to 224 °, as described above, the third plunger member 40C moves to the lower lid member 4D side with a constant acceleration motion while communicating with the opening 34A.
Since the sum of the axial movement amounts of the plunger members 40A and 40C is made constant by setting the cam surface 20A, the liquid discharge amount with respect to the rotation angle of the end face cam 20 is kept constant.
The second plunger member 40B moves from 76 ° to 104 °, and moves to the end face cam 20 side at a constant speed movement as in the case of the first plunger member 40A described above. Continue.

When the first plunger member 40A is moved from the position of 344 ° of the cam surface 20A shown in FIG. 11 (I) to the position of 0 ° shown in FIG. 9 (A), the opening 42 of the first plunger member 40A is In this state, the port 33A is disconnected from the opening 34A and is not communicated with any of the ports 33 and 35, that is, the ports 33 and 35 (valves) are closed.
During this time, the second plunger member 40B moves from the 104 ° to 120 ° position toward the end face cam 20 by a constant velocity motion, and continues a certain amount of liquid suction operation.
Further, since the third plunger member 40C is also moved from 224 ° to 240 °, similarly to the case of the first plunger member 40A described above, the third plunger member 40C is moved to the lower lid member 4D side by a constant velocity motion, and a certain amount of liquid is discharged. Continue operation.

  As described above, the first plunger member 40A returns to 0 ° of the cam surface 20A. Therefore, by repeating the operations described above, a constant amount of liquid is continuously discharged and sucked, and continuous suction and pulsation are performed. Discharging is performed.

According to this embodiment, there are the following effects.
(1) Since the liquid can be sucked into and discharged from the liquid measuring space simply by rotating the plunger member 40 inserted into the cylinder hole 31, a high hydraulic pressure is applied to the plunger member 40. Even if it adds, the outer peripheral surface of the plunger member 40 can contact | abut to the cylinder hole 31, and can be guided. Since the port (valve) is switched by the rotation of the plunger member 40, the port switching state does not change even when a high hydraulic pressure is applied. Since the liquid is leaked away from each other and the state of the valve does not change, a liquid discharge device with high pressure resistance can be obtained.
Further, unlike the case of the surface valve method, it is not necessary to increase the urging force of the surface valve member to increase the pressure resistance performance, so that the necessary torque for rotating the plunger member 40 is also larger than that in the case of the surface valve method. Therefore, the motor can be made smaller, and the structure of the liquid ejection device can be simplified. Therefore, it is possible to provide the liquid ejection apparatus 1 that has a simple structure and can be easily downsized.

(2) Since the three plunger members 40 are provided and the liquid discharge amount and the suction amount when each plunger member 40 is operated are made constant in proportion to the rotation angle of each plunger member 40, The liquid can be continuously discharged at a constant discharge amount, and a pulsation continuous pump can be configured. Furthermore, by controlling the rotation speed, the discharge amount for a certain time can be increased or decreased, and the discharge amount can be easily controlled.

(3) Since the opening 42 is formed in the intermediate portion of the side surface of the plunger member 40 and the side surface portions of the plunger member 40 are formed on both sides in the axial direction of the opening 42, the opening 42 side of the plunger member 40 is located on the cylinder hole 31. Even when pressed against the inner peripheral surface, the plunger member 40 does not tilt, the hydraulic pressure can be supported in a balanced manner, and the plunger member 40 can be smoothly driven forward and backward in the axial direction. Therefore, also from this point, the necessary driving force of the motor 2A can be reduced, and the liquid ejection apparatus 1 can be reduced in size.

(4) Since the cylinder block 30 is disposed in the container 4, even when liquid leaks from between the cylinder hole 31 and the plunger member 40, the liquid can be collected in the container 4, and a sealing material for preventing liquid leakage Therefore, assembly work and maintenance work can be easily performed.

(5) Since the cam follower that contacts the cam surface 20A includes the ball holding member 70 and the ball 75 held in the concave portion 71 of the ball holding member 70, the cam follower is composed of the end face cam 20 and the cam follower. A part can be reduced in size. That is, when a conventional roller is used, a rotating shaft that rotatably supports the roller is required, and this rotating shaft must protrude from the rod or the like that drives the plunger member 40 in the outer circumferential direction. The diameter of the movement (revolution) trajectory along the cam surface also increases. On the other hand, since the ball 75 is used in the present embodiment, the roller shaft can be omitted, and the diameter of the movement locus can be reduced correspondingly, and the liquid ejecting apparatus 1 can be downsized.

(6) When a roller is used, side slip occurs between the flat cam and the roller. Therefore, it is necessary to reduce the wear of the roller by forming the flat cam with oil-impregnated resin. Due to the deformation of the oil-impregnated resin at the time, an error in the stroke amount of the plunger occurs, and the liquid discharge accuracy decreases.
In contrast, in this embodiment, the ball 75 is brought into contact with the cam surface 20A, and the friction coefficient between the ball holding member 70 and the ball 75 is set lower than the friction coefficient between the cam surface 20A and the ball 75. Therefore, even if a force in the circumferential direction or the like is applied to the ball 75 along with the revolution, the force is absorbed by the sliding of the concave portion 71 of the ball holding member 70 and the ball 75. For this reason, no side slip or the like occurs between the cam surface 20A and the ball 75, and the ball 75 can roll without sliding with respect to the cam surface 20A. Therefore, it is not necessary to form the cam surface 20A with oil-impregnated resin or the like in consideration of friction as in the prior art, and the cam surface 20A can be formed with a hard member such as metal, and the ball 75 can also be formed with a hard member. The amount error can be reduced, and the liquid ejection accuracy can be improved.
Further, since the advancement / retraction of the plunger member 40 is uniquely set by the shape of the cam surface 20A of the end cam 20 via the ball holding member 70 and the ball 75, by appropriately setting the shape of the cam surface 20A, The movement of the plunger member 40 can be accurately controlled, and accurate discharge without pulsation can be performed.

(7) Further, the ball holding member 70 is made of a softer material than the ball 75 such as a resin, but holds the ball 75 with a hemispherical recess 71 that can accommodate an approximately hemispherical portion of the ball 75. Therefore, when a slip occurs between the ball 75 and the recess 71, the force generated by the slip can be supported over a wide area of the recess 71, so that the deformation of the ball holding member 70 can be prevented. Thereby, the movement of the plunger member 40 can be accurately controlled without generating an error in the movement amount of the plunger member 40. Accordingly, by arranging the three plunger members 40 and setting the shape of the cam surface 20A and the positional relationship between the openings 34A and 35A and the openings 42 to a predetermined relationship, the liquid suction amount and the discharge amount are set to the motor 2A. , That is, proportional to the rotation angle of the plunger member 40. If the motor 2A is rotated at a constant speed, a constant amount of liquid can be continuously discharged without pulsation.
Therefore, it is possible to provide the liquid discharge apparatus 1 having very excellent characteristics as compared with the conventional swash plate pump. That is, since the swash plate pump drives the plunger along the swash plate, the sliding portion with the swash plate is a flat contact, and the connection portion with the plunger (piston) is a spherical bush. In this swash plate pump, since the cam (swash plate) is limited to a flat surface, the discharge amount cannot be discharged every fixed amount in proportion to the rotation angle. Further, since it is necessary to reduce the wear and friction by supplying oil to the slide portion with the swash plate, it must be used while supplying oil, and handling is complicated.
On the other hand, in the liquid ejection device 1 of the present embodiment, since a three-dimensional cam can be used, a certain amount of liquid can be ejected according to the rotation angle, and the ball 75 is used, and the friction coefficient has a predetermined relationship. Since it is set, wear of the ball 75 or the like is less likely to occur, and refueling or the like can be made unnecessary.
Further, since the discharge amount per unit time can be set by the rotation speed of the motor 2A, the discharge amount can be controlled accurately and easily by the speed controller of the motor 2A, and the liquid discharge apparatus 1 that is easy to handle is obtained. be able to.

(8) In this embodiment, since the cam follower can be constituted by the two members of the ball holding member 70 and the ball 75, the configuration can be simplified and the size can be reduced as compared with the case where the roller shaft is used.

(9) Since the suction port 35 is opened on the outer peripheral surface of the cylinder block 30, the liquid can be smoothly supplied to the suction port 35 simply by disposing the cylinder block 30 in the container 4. In addition, since the opening of the suction port 35 is aligned with the bottom surface of the container 4, the liquid can be reliably supplied to the suction port 35 without leaving the liquid in the container 4.

(10) Since the discharge port 33 is shared by forming the discharge hole 33A on the central axis of the cylinder block 30, the configuration of the discharge port 33 can be simplified and liquid can be discharged from one discharge hole 33A. Therefore, continuous liquid discharge can be easily realized.

(11) Since only the container 4, the cylinder block 30, the plunger member 40, the connecting rod 44, the flexible coupling 43, and the support rod 39 are in contact with the liquid, the material of these parts is made of alumina ceramic, for example. As a result, the liquid ejection device 1 having excellent chemical resistance can be realized at a relatively low cost. For this reason, the transfer fluid which can be handled is not limited, It can utilize for discharge of various liquids, such as a chemical | medical solution, an adhesive agent, and various solvents.

  The present invention is not limited to the above-described embodiments, and modifications, improvements, and the like within the scope that can achieve the object of the present invention are included in the present invention. In the following description, the same or similar components as those in the above-described embodiment are denoted by the same reference numerals, and description thereof is omitted or simplified.

In the embodiment, the container 4 having a large volume with respect to the cylinder block 30 is used. However, as shown in FIG. 12, the cylinder block 30 is inserted and disposed in a case body 90 having the same size as the cylinder block 30. The liquid discharge device 1A may be used.
Here, a liquid supply groove 91 continuous in the circumferential direction is formed on the inner peripheral surface of the case body 90. The case body 90 is formed with a suction hole 92 that communicates with the liquid supply groove 91 and a discharge hole 93 that communicates with the discharge port 33. Further, since the distance between the cylinder block 30 and the ball holding member 70 can be reduced, the connecting rod 44 is not provided, and the plunger member 40 is directly connected to the ball holding member 70 via an Oldham joint.

Since the liquid ejection device 1A does not include the container 4, the liquid recovery unit 94 for returning the liquid leaking from the gap between the plunger member 40 and the cylinder hole 31 to the liquid supply groove 91 is provided in the cylinder block 30. In addition, a liquid leakage prevention seal 95 is provided.
The liquid recovery unit 94 includes a circumferential groove formed along the inner periphery of the cylinder hole 31 and a communication hole that communicates the circumferential groove with the liquid supply groove 91, and the liquid leaked from the gap Is collected in the liquid supply groove 91 through the circumferential groove and the communication hole.
The liquid leakage prevention seal 95 is made of a sealing material such as an O-ring disposed in an arc groove formed on the inner peripheral surface of the cylinder hole 31. The liquid is sealed from the cylinder block 30 to the support plate 37 side by sealing the gap. To prevent leakage.

Also in such a liquid ejection apparatus 1A, when the liquid is supplied from the suction hole 92 to the liquid supply groove 91, the liquid is supplied into the liquid metering space from the suction port 35 opened on the side surface of the cylinder block 30, and the discharge port 33 and Since the liquid is discharged through the discharge hole 93, the same effect as that of the above embodiment can be obtained.
Further, since the container 4 can be made unnecessary, the liquid ejecting apparatus 1A can be made smaller than the liquid ejecting apparatus 1.

  However, since the volume of the liquid supply groove 91 is smaller than that of the container 4, it is necessary to continuously supply the liquid from the suction hole 92 while discharging the liquid. There is an advantage that it can be performed at regular intervals. In the above embodiment, since the liquid can be recovered in the container 4, there is an advantage that the liquid recovery part 94 and the liquid leakage prevention seal 95 can be eliminated.

Further, the connection between the connecting rod 44 and the plunger member 40 and the ball holding member 70 is not limited to the Oldham joint, and other connection structures may be employed.
For example, a joint using magnetic force may be used as in the liquid ejection apparatus 1B shown in FIGS. In the liquid ejection device 1 </ b> B, the magnet holder 101 is fixed to one end of the plunger member 40, and two magnets 102 are attached to the magnet holder 101. Note that the magnet 102 has an end protruding from the magnet holder 101, and the protruding end surfaces are arranged to be an N pole and an S pole.

On the other hand, the ball holding member 70 includes a first ball holding member 111 formed with a recess 71 and a second ball holding member 112 disposed on the first ball holding member 111 via a ball bearing 49. Has been. Each ball holding member 111, 112 is integrated with a connecting pin 113 press-fitted into each ball holding member 111, 112.
Two magnets 114 are embedded in the end surface of the second ball holding member 112. At this time, the end surface of the magnet 114 is recessed from the end surface of the second ball holding member 112, and the magnet 102 is configured to fit into the recess. The two magnets 114 are also arranged so that the surfaces exposed to the recesses are the N pole and the S pole.

Also in such a liquid discharge apparatus 1B, when liquid is supplied from the suction hole 92 to the liquid supply groove 91, the liquid is supplied into the liquid metering space from the suction port 35 that opens to the side surface of the cylinder block 30, and the discharge port 33 and Since the liquid is discharged through the discharge hole 93, the same effects as the liquid discharge apparatus 1 and the liquid discharge apparatus 1A can be achieved.
Moreover, since it connects using the magnets 102 and 114, the plunger member 40 can be attached or detached easily, and the removal at the time of washing | cleaning and an assembly operation can be performed easily.
Furthermore, since two magnets 102 and 114 are provided, and their north and south poles are different from each other, the mounting direction of the plunger member 40 relative to the ball holding member 70, that is, the direction of the opening 42 can be made constant and can be assembled incorrectly. It can be assembled even more easily.

  The connection between the plunger member 40 and the connecting rod 44 and the ball holding member 70 is not limited to using an Oldham coupling or a magnet. For example, a cap nut is formed on the end surface of the ball holding member 70 to Other methods, such as forming and connecting a male screw to be screwed to the cap nut on the end face, may be employed. In particular, as in the case where the container 4 is not used, when the plunger member 40 and the ball holding member 70 can be directly connected and the respective members can be accurately aligned, a connecting structure that allows an axial displacement of an Oldham joint or the like is provided. There is no need to adopt.

  The material of the cylinder block 30, the plunger member 40, etc. can be selected from ceramics such as alumina ceramic and silicon nitride, metals such as cemented carbide and stainless steel, and may be selected depending on the type of liquid used.

The shape of the cam surface 20A of the end cam 20 is not limited to that of the cam diagram of the above embodiment. For example, the cam surface portion in which each plunger member 40 is caused to move at a constant acceleration when the openings 42 of the two plunger members 40 communicate with the openings 34A and 35A may be a sine curve cam surface. Each cam surface may be designed so that the total amount of movement of the two plunger members 40 is constant.
Further, in the case of the liquid discharge apparatus 1 that does not need to discharge a constant amount of liquid continuously without pulsation, the cam surface 20A may be designed according to the discharge operation. In short, the shape of the cam surface 20A may be designed according to the liquid discharge operation required for the liquid discharge device, and also in such a liquid discharge device, the plunger member 40 inserted into the cylinder hole 31 is rotated. On the other hand, by moving in the axial direction, it is possible to realize a liquid discharge apparatus that is small and can perform high-precision discharge.

  The configuration of the cylinder block 30 is not limited to that of the above embodiment, and for example, the discharge port 33 and the suction port 35 may be set in reverse. The number of cylinder holes 31 and plunger members 40 is not limited to three, and two or four or more may be provided. However, in the case of two, since the liquid discharge becomes intermittent, it is preferable that the number is three or more when continuously discharging, and in particular, the configuration can be simplified as compared with the case where four or more are provided. In terms of the point, it is most preferable to provide three as in the above embodiment.

  Further, the communication hole 33B and the suction port 35 of the discharge port 33 formed in the cylinder hole 31 are not limited to those having a circular cross-sectional shape, that is, the discharge-side openings 34A and the suction-side openings 35A are formed in a circular shape. May be formed in other shapes such as an ellipse. In particular, each of the openings 34A and 35A requires that the opening 42 of each rotating plunger member 40 continues to communicate within a predetermined angular range, so that the length dimension in the rotational direction is the axial direction of the cylinder hole 31 perpendicular to the opening. If the cross-sectional shape is elliptical, for example, the short axis is provided along the axial direction of the cylinder hole 31, and the long axis is provided in the rotation direction of the plunger member 40. It is preferable. If such a configuration is adopted, the communication area with the opening 42 of the plunger member 40 can be maintained without increasing the opening areas of the openings 34A and 35A so much. However, there is an advantage that the ports 33 and 35 can be easily processed if they are formed in a circular shape as in the above embodiment.

  Further, the plunger member 40 is not limited to the one in which the opening 42 is formed at a position away from the end face of the plunger member 40 by a predetermined dimension, that is, the opening 42 is formed in the middle portion of the side surface. You may use the D-cut type plunger member formed continuously from the end surface. In the case of a D-cut plunger member, it is only necessary to form a concave portion continuous from the end surface on the side surface, so that the processing is facilitated. Even if it is very thin, about 2 mm, there is an advantage that it can be formed relatively easily.

As the motor 2A, various motors such as a stepping motor, a servo motor, a synchronous motor, a DC motor, an induction motor, a reversible motor, and an air motor can be used.
Further, the shape, structure, and the like of the portions other than these are not limited to the above-described embodiments, and various modifications can be made.

  The liquid ejection devices 1, 1A and 1B according to the present invention are not only used for a constant flow rate that keeps a constant flow rate for a predetermined time. It can be used when a small amount of liquid is discharged into the line to be mixed or sampled from the line according to the flow rate measurement value of the line through which the liquid flows.

  Further, a plunger pump is interposed in a line through which a predetermined liquid flows to operate the motor 2A so that the pressure of the line before and after the pump is in an equilibrium state, and the rotation amount and the number of pulses of the motor 2A in the equilibrium state The flow rate may be measured from In particular, the liquid discharge device of the present invention is suitable for sucking and discharging a very small amount of liquid, and therefore can be used as a very small flow meter.

  INDUSTRIAL APPLICABILITY The present invention can be used for a liquid ejecting apparatus that can be simplified in structure and easily reduced in size, and can cope with a case where the hydraulic pressure is high.

It is a front view which shows 1st Embodiment of this invention. It is sectional drawing which shows the principal part of 1st Embodiment. It is sectional drawing which shows the principal part of the container part of 1st Embodiment. It is a perspective view which shows a cylinder block and a plunger member. It is sectional drawing which shows a cylinder block and a plunger member. It is a disassembled perspective view which shows an Oldham coupling. It is a perspective view which shows an end surface cam and a ball | bowl holding member. It is a cam diagram of an end face cam. It is operation | movement explanatory drawing in 1st Embodiment. It is operation | movement explanatory drawing in 1st Embodiment. It is operation | movement explanatory drawing in 1st Embodiment. It is sectional drawing which shows the principal part in the modification of this invention. It is sectional drawing which shows the principal part in the other modification of this invention. It is a perspective view which shows the principal part in the modification of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,1A, 1B ... Liquid discharge apparatus, 2A ... Servo motor, 2C ... Output shaft, 4 ... Container, 20 ... End surface cam, 20A ... Cam surface, 22 ... Oldham coupling, 23 ... Cam main body, 24 ... Gear shaft member, DESCRIPTION OF SYMBOLS 30 ... Cylinder block, 31 ... Cylinder hole, 33 ... Discharge port, 35 ... Suction port, 40, 40A, 40B, 40C ... Plunger member, 41 ... Liquid storage space, 42 ... Opening, 44 ... Connecting rod, 46 ... Oldham coupling 60 ... Cam follower guide block, 70 ...
Ball holding member, 72 ... teeth, 75 ... ball, 90 ... case body, 101 ... magnet holder, 102, 114 ... magnet, 111 ... first ball holding member, 112 ... second ball holding member.

Claims (5)

A cylinder block having three cylinder holes with one end closed and the other end opened;
Three plunger members inserted into the cylinder holes from the other end side;
Driving means for rotating each plunger member about each cylinder hole while reciprocating in the axial direction of the plunger member about the axial center axis;
The cylinder block has a suction port having one end opened on the inner peripheral surface of each cylinder hole and the other end opened on the outer surface of the cylinder block; one end side opened on the inner peripheral surface of each cylinder hole; A discharge port opened on the outer surface of the block;
A suction side opening and a discharge side opening communicated with the suction port and the discharge port, respectively, are formed on the inner peripheral surface of each cylinder hole,
Each plunger member is opened on a side surface of the plunger member, and with the rotation of the plunger member, the suction side communication state communicated with the suction port, the port switching state not communicated with any of the suction port and the discharge port, Side opening that can be sequentially switched to a discharge side communication state that is connected to the discharge port, a port switching state that is not connected to any of the discharge port and the suction port, and one end that is connected to the side opening and that is closed on the cylinder hole A liquid storage space opened on the end surface of the plunger member facing the side,
The suction side opening and the discharge side opening in each cylinder hole are such that the side opening of one of the three plunger members does not communicate with each opening, and the side opening of the other two plunger members is connected to each opening. The state of communication,
Of the three plunger members, the side opening of two plunger members communicates with the suction side opening, and the side opening of the other one plunger member communicates with the discharge side opening;
A state in which the side opening of one plunger member of the three plunger members communicates with the suction side opening and the side opening of the other two plunger members communicates with the discharge side opening is defined as rotation of each plunger member. Along with the switchable,
When the side opening of the plunger member is in the suction side communication state, the driving means rotates the plunger member in a direction away from one end side of the cylinder hole, and the side opening of the plunger member is in the discharge side communication state. The plunger member is rotated in a direction approaching one end side of the cylinder hole while rotating, and when the side opening of the plunger member is in the port switching state, the plunger member is rotated without moving in the axial direction. With
When only the side opening of one plunger member communicates with the suction side opening, the plunger member is moved in a direction away from one end side of the cylinder hole so that the amount of movement with respect to its own rotation angle is constant,
When only the side opening of one plunger member communicates with the discharge side opening, the plunger member is moved in a direction approaching one end side of the cylinder hole so that the amount of movement with respect to its rotation angle is constant,
When the side openings of the two plunger members are communicated with the suction side opening, the plunger members are moved away from one end side of the cylinder hole, and the amount of movement of each plunger member with respect to the rotation angle of each plunger member Is set to be the same as the amount of movement of the plunger member when only the side opening of the one plunger member communicates with the suction side opening,
When the side openings of the two plunger members are in communication with the discharge side openings, the plunger members are moved in a direction approaching one end side of the cylinder hole, and the amount of movement of each plunger member with respect to the rotation angle of the plunger member is The liquid ejection apparatus according to claim 1, wherein the total is set to be the same as a movement amount of the plunger member when only the side surface opening of the one plunger member communicates with the ejection side opening . The liquid ejection apparatus according to claim 1,
The cylinder block is formed in a substantially cylindrical shape,
The cylinder holes are formed at equal intervals on a concentric circle centered on the central axis of the cylinder block,
The discharge port includes a single discharge hole formed along the central axis of the cylinder block, and a communication hole that communicates the discharge hole with each cylinder hole. apparatus. The liquid ejection apparatus according to claim 1 or 2,
The side opening of the plunger member is formed at a position a predetermined distance away from the end of the plunger member on the side of the plunger member, and the side of the plunger member is left on each plunger end side of the side opening. Liquid ejecting device. The liquid ejection apparatus according to any one of claims 1 to 3,
The cylinder block is arranged in a container capable of storing a liquid for discharge, and is configured to be able to collect the liquid in the container when the liquid leaks between the cylinder hole and the plunger member. The liquid ejection apparatus according to any one of claims 1 to 4,
The driving means includes
A motor, a cam rotated by the motor, and a cam follower connected to each plunger member;
The cam is configured to include a cam surface having a predetermined shape formed on an end surface thereof, and a gear provided on a rotation center shaft portion and protruding from the cam surface.
One end of the cam follower is integrally connected to the plunger members so as to be reciprocally driven and rotatable, and the other end has a gear that can mesh with the gear of the cam and that can advance and retract in the axial direction with respect to the gear. A cam follower body formed with a substantially hemispherical recess formed on the other end side end surface, and a ball disposed in the recess and capable of contacting the cam surface,
The friction coefficient between the ball and the recess is set to be smaller than the friction coefficient between the cam surface and the ball,
When the cam is driven to rotate by the motor, the cam follower body is rotated by meshing with the gear of the cam, and the cam surface abutting on the ball is rotated to move forward and backward in the axial direction according to the shape of the cam surface. Driven,
The liquid ejecting apparatus, wherein the plunger member is driven to rotate and advance / retreat integrally with a cam follower body.

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