JP6982736B2 - Coating nozzle head and liquid coating device equipped with it - Google Patents

Description

The present invention relates to a coating nozzle head and a liquid coating device including the coating nozzle head. In particular, the present invention relates to a coating nozzle head for discharging a highly viscous liquid and a liquid coating apparatus including the coating nozzle head.

A device for discharging a liquid material by a reciprocating operation of a plunger is known. For example, it is a jet type liquid coating device shown in Patent Document 1.

In recent years, high speed coating work has been required from the viewpoint of improving productivity. In this type of liquid coating apparatus, there is an increasing demand for further increasing the number of discharges within a certain period of time. Therefore, it is necessary to reciprocate the plunger of the liquid coating device at high speed.

Actuators such as motors, air, and piezoelectric elements are often used as the drive source for reciprocating the plunger. The piezoelectric element can operate at high speed. However, since the displacement amount is small, it is generally used by increasing the displacement amount in combination with the displacement expansion mechanism. For example, the one described in Patent Document 2 is known.

Hereinafter, a conventional liquid coating device using the displacement expanding mechanism and the piezoelectric element will be described with reference to FIGS. 1 to 4.

A conventional liquid coating device is shown in FIG. 1 of the front view. FIG. 2 shows a cross-sectional view of a discharge portion of a conventional liquid coating device. The liquid coating device 1 discharges the discharged droplet 65 from the nozzle hole 60. The liquid coating device 1 includes a supply flow path 52 that communicates with the nozzle hole 60 and is supplied with a liquid material, a plunger 12a in which the tip portion reciprocates in the supply flow path 52, and an actuator 2a that reciprocates the plunger 12a. , A displacement expanding mechanism 3a, and the like.

The displacement expanding mechanism 3a is composed of elastically deformable U-shaped members 5, 6, 7, 8 and 9 in which the actuators 2a are arranged symmetrically and the plunger 12a is connected to the lower portion. FIG. 3 describes the operation of the plunger 12a when it is raised. FIG. 4 describes the operation of the plunger 12a when it is lowered. The actuator 2 moves the plunger 12 upward by applying a force that separates both ends of the U-shaped members 5, 6, 7, 8, and 9. On the contrary, the actuator 2a moves the plunger 12a downward by applying a force that brings both ends of the U-shaped members 5, 6, 7, 8, and 9 close to each other. This is a feature.

Japanese Unexamined Patent Publication No. 10-314640 Japanese Unexamined Patent Publication No. 2015-051399

In order to discharge the high-viscosity liquid material, it is necessary to drive the plunger 12 at high speed with a large displacement amount.

In the conventional displacement expanding mechanism 3a, the plunger 12a is reciprocated in the vertical direction by elastically deforming the U-shaped members 5, 6, 7, 8, and 9. In order to secure the required displacement amount, it is necessary to reduce the rigidity of the U-shaped members 8 and 9. Along with this, the natural frequency becomes low, and there is a limit to improving the displacement response speed of the plunger 12.

Therefore, the displacement amount of the plunger 12a can be increased by increasing the displacement expansion ratio of the displacement expansion mechanism 3a with respect to the displacement of the actuator 2, but it is difficult to achieve both with high-speed drive.

The present invention solves such a conventional problem, and is capable of controlling the coating of a high-viscosity liquid material at high speed and stably, a displacement expanding mechanism, a coating nozzle head provided with the mechanism, and a liquid coating provided with the same. The purpose is to provide the device.

In order to achieve the above object, the nozzle hole for discharging the liquid material, the supply flow path for supplying the liquid material to the nozzle hole, the reciprocating plunger that abuts on the liquid in the supply flow path, and the displacement to the plunger. A liquid coating device is used that includes a displacement expanding mechanism that imparts a displacement and an actuator that imparts a displacement to the displacement expanding mechanism, and at least one of the contact portions between the displacement expanding mechanism and the actuator is a curved surface.

According to the configuration of the present invention, in industrial applications such as manufacturing of electronic devices, it is possible to control the application of a high-viscosity liquid material containing functional particles at high speed and stably, and the optimum amount can be applied to a required place. It can be applied in any pattern.

Front view of conventional liquid coating device Cross-sectional view of the discharge part of a conventional liquid coating device Operational illustration of the conventional liquid coating device when the plunger is raised Operational illustration of the conventional liquid coating device when the plunger is lowered Sectional drawing of the liquid coating apparatus of embodiment of this invention Cross-sectional view of the tip of the plunger according to the embodiment of the present invention Cross-sectional view of the tip of the plunger according to the embodiment of the present invention Cross-sectional view of the tip of the plunger according to the embodiment of the present invention Cross-sectional view of the tip of the plunger according to the embodiment of the present invention Cross-sectional view of the tip of the plunger according to the embodiment of the present invention Cross-sectional view of the tip of the plunger according to the embodiment of the present invention Sectional drawing of the liquid coating apparatus of embodiment of this invention Sectional drawing of the liquid coating apparatus of embodiment of this invention Sectional drawing of the liquid coating apparatus of embodiment of this invention Sectional drawing of the liquid coating apparatus of embodiment of this invention Plunger displacement behavior diagram of the embodiment of the present invention Sectional drawing of the liquid coating apparatus of embodiment of this invention Sectional drawing of the liquid coating apparatus of embodiment of this invention Sectional drawing of the liquid coating apparatus of embodiment of this invention Sectional drawing of liquid coating apparatus of modification of embodiment of this invention

Hereinafter, embodiments will be described with reference to the drawings. Since the description is an example, the invention of the present application is not limited to the following description.
<Liquid coating device>
<Structure>
FIG. 5 is a cross-sectional view of the liquid coating apparatus 100 according to the embodiment of the present invention, and the basic configuration will be described below.

The liquid coating device 100 discharges the discharged droplet 65 of the liquid material from the nozzle hole 60. The liquid coating device 100 includes a supply flow path 52 that communicates with the nozzle hole 60 and supplies a liquid material, a plunger 12 whose tip portion reciprocates in the supply flow path, and an actuator 2 that reciprocates the plunger 12. A displacement expanding mechanism 3 is provided.

The features of each component will be described below.

<Nozzle hole 60>
The nozzle hole 60 is a through hole provided in a metal such as cemented carbide, stainless steel, aluminum, or titanium. The material may be not only metal but also a resin material such as ceramic or PEEK. However, it is necessary to select a material that does not wear with the contained particle material or erode or elute with the liquid material when the liquid material is discharged.

Further, the inner diameter of the nozzle is selected from the range of Φ0.05 mm to 0.5 mm according to the size of the discharged droplet. The nozzle length is selected from the range of 0.05 mm to 5 mm according to physical properties such as viscosity, thixotropic property, surface tension, and contact angle with the nozzle surface of the liquid material.

In FIG. 5, for simplification, the supply flow path 52 and the nozzle hole 60 are shown as an integrated structure. However, the nozzle hole 60 may be separately manufactured and assembled as a separate part in order to improve manufacturing and maintainability.

<Supply flow path 52>
The same material as the nozzle hole 60 can be used for the supply flow path 52. The cross section of the supply flow path 52 may be a circular shape having a diameter of about 0.5 to 10 mm or a rectangular shape having the same cross-sectional area. A circular shape is preferable from the viewpoint of workability and prevention of bubble accumulation.

The supply flow path 52 communicates a tank (not shown) for supplying a liquid material with a nozzle hole 60. The supply flow path 52 has a function of supplying the liquid material filled in the tank to the nozzle hole 60.

<Plunger 12>
The plunger 12 moves through the holes in the guide 110 and the sealing material 104. This pushes the liquid material out of the nozzle hole 60 in the supply flow path 52. The same material as the nozzle hole 60 can be used for the plunger 12. However, as the material of the plunger 12, it is necessary to select a material that is not deteriorated by wear or is not eroded or dissolved in the liquid material due to the guide 110, the sealing material 104, and the particle material contained in the liquid material. Further, in order to drive the plunger 12 at high speed, it is preferable to select a material having a small specific gravity. Further, it is preferable to reduce the volume of the plunger 12 itself to the minimum to reduce the weight.

The plunger 12 has a function of converting the drive energy of the actuator 2 into the discharge energy of the liquid material. When the plunger 12 reciprocates in the vicinity of the nozzle hole 60, pressure is applied to the liquid material in the vicinity of the nozzle hole 60 to eject the discharged droplet 65 of the liquid material from the nozzle hole 60.
The tip shape of the plunger 12 may be a flat shape as shown in FIG. 5, but may be a convex shape as shown in FIGS. 6A to 6F.
<Guide 110>
The guide 110 moves the plunger 12 straight up and down. The guide 110 has a through hole, and the plunger 12 moves up and down through the through hole.

<Actuator 2>
The actuator 2 is used as a drive source for reciprocating the plunger 12, and a motor, air, a piezoelectric element, or the like is often used.

<Displacement expansion mechanism 3>
As with the plunger 12, it is desirable to select a material that can achieve both wear resistance and light weight for the displacement expansion mechanism 3, and the displacement expansion mechanism 3 is composed of a fulcrum portion 101 and a lever 102.

The displacement expanding mechanism 3 has a function of expanding the displacement amount of the plunger 12 to be larger than the displacement amount of the actuator 2. By reciprocating the plunger 12 more greatly using the smaller actuator 2, a highly viscous liquid material or a liquid material containing large particles can be ejected from the nozzle hole 60.

In FIG. 5, the lever 102 is installed on the fulcrum portion 101 that is in contact with the housing 30, and the plunger 12 is held in a state of being in contact with the tip portion of the lever 102 by the tensile force of the elastic body 103. The elastic body 103 may be installed between the plunger 12 and the housing 30 and held by a compressive force.

The elastic body 103 may be a spring coil spring or a leaf spring. The spring constant is preferably selected from the range of 0.1 to 10 N / mm. This is because if the spring constant is too small, the natural frequency becomes low and high-speed driving becomes impossible, and if the spring constant is too large, the change in spring force due to the displacement amount of the actuator becomes large and the driving becomes unstable.

<Contact portion between lever 102 and actuator 2>
At least one of the contact portions between the lever 102 and the actuator 2 has a curved surface. As a result, the actuator 2 abuts on the upper surface of the lever 102 to apply the displacement. The lever 102 rotates around the fulcrum portion 101. By this rotation, the plunger 12 installed at the tip of the lever 102 can reciprocate up and down due to the displacement of the actuator 2.

Further, in order to reduce the sliding resistance of the contact portion between the lever 102 and the actuator 2, at least one of the contact surfaces may have an uneven shape. That is, either the concave shape or the convex shape may be present.
Forming unevenness <Contact surface between fulcrum 101 and lever 102>
The fulcrum portion 101 has a cylindrical shape. The tip of the lever 102 comes into contact with the action point 109 on the flange plane of the plunger 12 on a convex curved surface. Further, the portion of the lever 102 that comes into contact with the fulcrum portion 101 is preferably a concave curved surface having a radius of curvature equal to or greater than the radius of curvature of the fulcrum portion 101 that abuts. These may be integrated into a component configuration. The concave portion and the convex portion may have an inverse relationship.

Here, the center of rotation around the fulcrum portion 101 of the lever 102 is set as the fulcrum 107, the contact surface between the lever 102 and the actuator 2 is set as the force point 108, and the point where the lever 102 pushes the plunger 12 is set as the action point 109.

As shown in FIG. 5, the fulcrum 107, the force point 108, and the action point 109 do not exist on the same straight line and form a triangle.

In FIG. 5, the actuator 2 and the plunger 12 are located in the same direction with respect to the fulcrum 107 which is the center of rotation of the lever 102, but they may be located in different directions.

It is important that the distance L1 from the fulcrum 107 to the force point 108 is smaller than the distance L2 from the fulcrum 107 to the point of action 109. This makes it possible to greatly increase the displacement of the plunger 12 as compared with the displacement of the actuator 2.

When the actuator 2 is a piezoelectric element, it is possible to apply a preload of a compressive load by an elastic body 103 in order to prevent the piezoelectric element from being destroyed by a tensile force. As a result, the drive reliability of the actuator 2 can be improved.

<Applying operation>
Next, the coating operation of the liquid material will be described below.
(1) Supply of Liquid Material When the tip of the plunger 12 moves upward in the supply flow path 52 filled with the liquid material, the liquid material is supplied to the vicinity of the nozzle hole 60. By applying a back pressure of about 0.1 to 500 kPa to the tank (not shown) for supplying the liquid material directly connected to the supply flow path 52, the supply speed of the liquid material is increased and the discharge interval is shorter. It is possible to apply a high viscosity material. The higher the back pressure, the faster the supply rate of the liquid material, but in the case of the particle-containing paste material, there is a problem that the solid content and the liquid component are separated, so the back pressure should be about 300 kPa or less. preferable. Even if the back pressure is 300 kPa or less, if the liquid material seeps out from the nozzle hole 60, the gas-liquid interface (meniscus surface) in the nozzle hole 60 becomes unstable, and stable droplet ejection can be performed. It is indispensable to set the back pressure according to the liquid material and the discharge conditions because it may disappear.

(2) Liquid Discharge When the plunger 12 moves downward in the vicinity of the nozzle hole 60, the liquid pressure in the vicinity of the nozzle hole 60 rises and the discharged droplet 65 of the liquid material is discharged. Here, the sealing material 104 is installed in close contact with the plunger 12 and the housing 30 so that the liquid pressure in the vicinity of the nozzle hole 60 does not decrease even during the vertical movement of the plunger 12. The faster the downward movement speed of the plunger 12, the more rapidly the nozzle pressure can be increased. Therefore, the discharge speed of the liquid material that pops out from the nozzle hole 60 at the head can be increased. Further, by moving the plunger 12 upward rapidly after the leading liquid material starts to pop out from the nozzle hole 60, the discharge speed of the subsequent liquid material can be rapidly reduced. As a result, even with a high-viscosity liquid material, it is possible to shorten the stringing of the discharged droplets, and it is possible to stably discharge a smaller amount of the discharged droplets 65.

In FIG. 5, the tip of the plunger 12 comes into contact with the liquid material in the supply flow path 52 and moves up and down. However, as shown in FIG. 7, the tip of the plunger 12 comes into direct contact with the liquid material. It is also possible to make the diaphragm 105 surface move up and down without liquid.

FIG. 7 is a cross-sectional view of a modified example of the liquid coating device 100 of FIG. The plunger 12 is located on the upper surface of the diaphragm 105. The plunger 12 pushes and pulls the diaphragm 105.

<Modification example 1 of displacement expansion mechanism 3>
Subsequently, a modification of the displacement expansion mechanism 3 will be described below.

FIG. 8A has the same basic configuration as the liquid coating apparatus 100 described above. Displayed for comparison. Here, as shown in FIG. 8B, a curved bearing 106 may be installed on the surface of the actuator 2 that does not come into contact with the lever 102.

With such a configuration, the force in the short axis direction (left-right direction in FIG. 8A) does not act on the actuator 2, and the drive reliability can be improved.

<Deformation example 2 of displacement expansion mechanism 3>
Further, in the displacement expanding mechanism 3, in order to improve the displacement response speed of the plunger 12 and ensure long-term continuous drive reliability, the drive resistance of the actuator 2, the lever 102, the fulcrum portion 101, and the sliding portion of the plunger 12 is set. It is necessary to reduce it.

Therefore, as shown in FIG. 8C, the surface on which the actuator 2 and the lever 102 abut and the surface on which the lever 102 and the fulcrum portion 101 abut are not overlapped with each other when viewed from the long axis direction of the actuator 2. The reaction force received when the 102 is driven can be reduced, and extra sliding resistance can be suppressed. That is, the surface where the lever 102 and the fulcrum portion 101 come into contact with each other is not included in the dotted line in FIG. 8C.

Further, it is also possible to reduce the contact area and reduce the sliding resistance by forming irregularities or grooves of 0.1 μm or more on either or both of the sliding surfaces.

In addition, in order to reduce the sliding resistance of the contact interface, it is more preferable to apply a solid lubricant or grease to form a film.

<Deformation example 3 of displacement expansion mechanism 3>
FIG. 9A shows the relationship between the displacement of the plunger 12 and the time. Ideally, the plunger 12 should be displaced like an ideal curve. However, in reality, a time response delay occurs, and the plunger 12 is displaced on the actual displacement curve. In particular, when a highly viscous liquid material is discharged, the actual displacement curve is obtained. This occurs remarkably because the drive resistance of the plunger 12 becomes large when a large displacement is applied to the plunger 12.

There are two main factors for this.
(1) The closer the tip of the plunger 12 is to the nozzle hole 60, the higher the pressure near the nozzle hole 60 at the tip of the plunger 12.
(2) This is because the tensile force and the compressive force of the elastic body 103 increase as the displacement of the actuator 2 alone and the displacement enlargement magnification increase.

As a countermeasure for this, as shown in FIG. 9B, it is preferable that the surface on which the actuator 2 and the lever 102 abut is formed of curved surfaces having different radii of curvature. FIG. 9B is a cross-sectional view of a modified example of the liquid coating device 100.
When the contact surface on the lever 102 side is a convex curved surface on the surface in contact with the lever 102 of the actuator 2, the radius of curvature of the surface on the lever 102 side shall be smaller than the radius of curvature of the surface on the actuator 2 side. Is preferable. On the other hand, when the contact surface on the lever 102 side is a concave curved surface, it is preferable that the radius of curvature of the surface on the lever 102 side is larger than the radius of curvature of the surface on the actuator 2 side.

FIG. 9C is a cross-sectional view of a modified example of the liquid coating device 100, and is a cross-sectional view of the liquid coating device 100 at the start of lowering of the plunger 12. FIG. 9D is a cross-sectional view of a modified example of the liquid coating device 100, and is a cross-sectional view of the liquid coating device 100 at the end of lowering of the plunger 12. As shown in FIG. 9C, the distance (arrow) between the force point at which the actuator 2 pushes the lever 102 and the fulcrum 107 at the start of descent of the plunger 12 is relatively short, and the displacement expansion is larger, so that the displacement response rises faster. It becomes possible to change. Further, as shown in FIG. 9D, at the end of the descent of the plunger 12, the distance (arrow) between the force point at which the actuator 2 pushes the lever 102 and the fulcrum 107 becomes relatively long, and the displacement expansion becomes smaller, so that the pushing load of the plunger 12 is reduced. Can be made a larger force, and the displacement response can be made faster without losing the drive resistance of the plunger 12.

In this case, when the plunger 12 moves downward, the length of the arrow changes, so that the displacement expansion magnification of the displacement expansion mechanism 3 can be gradually changed to a small value.

<Modification example 4 of displacement expansion mechanism 3>
Further, in order to discharge a small amount of the high-viscosity liquid material, it is important to drive the plunger 12 at high speed with a large force with a relatively small displacement amount. For that purpose, it is necessary to keep the displacement expansion magnification of the displacement expansion mechanism 3 to the minimum necessary and reduce the mass of the lever 102 to the minimum to reduce the weight.

However, the structure must be such that the actuator 2 and the elastic body 103 do not interfere with each other, which limits the design range. This is the same even when the elastic body 103 is installed between the plunger 12 and the housing 30 and is held by a compressive force.

As an embodiment of this measure, FIG. 10 shows a cross-sectional view of a modified example of the liquid coating device 100. As shown in FIG. 10, the displacement direction of the actuator 2 has an inclination θ with respect to the displacement direction of the plunger 12. This inclination θ is often selected from the range of 1 degree to 90 degrees, and is most effective in the range of 10 to 60 degrees. Note that FIG. 10 shows a state before the operation of the plunger 12.
When the plunger 12 operates, the displacement direction of the actuator 2 is tilted with respect to the displacement direction of the plunger 12.

With such a configuration, the surface on which the actuator 2 and the lever 102 abut and the surface on which the lever 102 and the fulcrum portion 101 abut are not overlapped when viewed from the long axis direction of the actuator 2, but the actuator 2 The distance between the fulcrum 107 and the force point 108 in the direction orthogonal to the displacement direction of is set to be smaller.

Moreover, since the physical distance between the actuator 2 and the elastic body 103 becomes large, the length of the lever 102 can be shortened.

Therefore, the weight of the lever 102 can be reduced, and the moment of inertia of the lever 102 and the movable portion such as the plunger 12 can be reduced by about 50% to 90%.

When a predetermined torque is applied, the displacement acceleration is inversely proportional to the moment of inertia, so the displacement acceleration of the plunger 12 can be increased to about 2 to 10 times, which is useful for discharging a small amount of high-viscosity liquid material. be.

Further, in FIG. 10, the actuator 2 and the plunger 12 are located in the same direction with respect to the fulcrum which is the center of rotation of the lever 102, but they may be located in different directions.

The liquid coating apparatus of the present invention can control the coating of a liquid material containing functional particles at high speed and stably. Further, the liquid coating apparatus of the present invention can apply an optimum amount to a required portion in a non-contact manner at high speed with an arbitrary pattern.

The liquid coating apparatus of the present invention can be used in industrial applications such as manufacturing electronic devices in which long-term continuous driving is indispensable. Further, the liquid coating apparatus of the present invention is
It is preferable as a displacement expansion mechanism for coating arbitrary patterns and a liquid coating device equipped with it for the purpose of 3D coating on three-dimensional structures such as uneven surfaces and curved surfaces, and improving productivity in manufacturing high-mix low-volume electronic devices. Used.

1 Liquid coating device 2, 2a Actuator 3, 3a Displacement expansion mechanism 5-shaped member 8-shaped member 12, 12a Plunger 30 Housing 52 Supply flow path 60 Nozzle hole 65 Discharge droplet 100 Liquid coating device 101 fulcrum 102 Lever 103 Elastic Body 104 Sealing material 105 Diaphragm 106 Bearing 107 Support point 108 Power point 109 Acting point 110 Guide

Claims (11)

Nozzle holes for discharging liquid materials and
A supply flow path for supplying a liquid material to the nozzle hole,
A plunger that reciprocates in contact with the liquid in the supply flow path,
A displacement expansion mechanism that gives displacement to the plunger,
Including an actuator that imparts a displacement to the displacement expansion mechanism.
The displacement expansion mechanism has a lever portion and a strut portion, and has a lever portion and a strut portion.
At least one of the contact portions between the displacement expansion mechanism and the actuator is a curved surface .
A liquid coating device that changes the distance between a fulcrum that is the center of rotation around the strut portion and a force point that is a contact surface between the lever portion and the actuator. One end of the actuator has the lever portion.
The liquid coating device according to claim 1, wherein the other end of the actuator has a bearing, and the curvature of the contact portion between the other end and the bearing is the same. The liquid coating apparatus according to claim 1 or 2 , further comprising an elastic body connected to the plunger. The liquid coating device according to any one of claims 1 to 3, wherein the fulcrum portion has a curved surface. A fulcrum that is the center of rotation around the fulcrum portion of the lever portion, and a force point that is a contact surface between the lever portion and the actuator.
The point of action that is the contact surface between the lever and the plunger is
The liquid coating apparatus according to any one of claims 1 to 4, which has a positional relationship that does not exist on the same straight line. The liquid coating device according to any one of claims 1 to 5, wherein at least one of the contact surfaces between the displacement expanding mechanism and the actuator has an uneven shape. At the contact surface between the displacement expansion mechanism and the actuator,
The radius of curvature of the contact surface on the side of the displacement expansion mechanism,
The liquid coating device according to any one of claims 1 to 6, wherein the radius of curvature of the contact surface on the actuator side is different from that of the contact surface. The liquid coating device according to claim 7, wherein the radius of curvature of the contact surface on the side of the displacement expanding mechanism is smaller than the radius of curvature of the contact surface on the side of the actuator. The liquid coating device according to any one of claims 1 to 8, wherein the position of the contact point between the displacement expanding mechanism and the actuator changes according to the operating position of the plunger. The liquid coating device according to any one of claims 1 to 9, wherein the displacement direction of the actuator is inclined with respect to the displacement direction of the plunger. The liquid coating device according to any one of claims 1 to 10, wherein a piezoelectric element is used for the actuator.

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