JPH06328029A - Nozzle device - Google Patents

Abstract

PURPOSE:To prevent the leakage of a coating soln. from a nozzle orifice even when the tip of a needle and the nozzle orifice fitted thereto are abraded. CONSTITUTION:A first piezoelectric element 21 is arranged in a piezoelectric element casing 20 so as to be stretchable in a vertical direction while a second piezoelectric element 22 is made stretchable in a horizontal direction and arranged so as to come into close contact with the piezoelectric element casing 20 at the time of stretching and contraction to generate compression force. The second piezoelectric element 22 and the fixing member 24 fitted to the piezoelectric element 22 in the stretching and contracting direction thereof are fixed to one end of the first piezoelectric element 21. The other end of the first piezoelectric element 21 is connected to one end of the lever 31 supported on a fulcrum 32 and the other end of the lever 32 is connected to a needle 33. The tip of the needle 33 is fitted in a nozzle orifice 39. The needle 33 is energized by a second spring 35 so as to close the tip of the needle and the nozzle orifice 39.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a nozzle device for preventing leakage of discharged material due to wear of a nozzle discharging portion.

[0002]

2. Description of the Related Art When a paint is discharged from a nozzle to write letters or symbols on a steel plate, or a glue is discharged to paste, a needle valve that combines a nozzle and a needle is driven by a solenoid coil and a spring. Then, a device for controlling the discharge of paint and glue is used.

FIG. 5 shows a sectional view of a marking nozzle for marking characters and symbols on a steel plate or the like with a paint as such a device. The tip of the needle is fitted to the nozzle tip 1, and the needle 2 penetrates the diaphragm 3 and is joined to the plunger 8. The pressure chamber 6 is provided with a paint inlet 4. A fixed iron core 9 for attracting the plunger 8 is provided on the side opposite to the needle of the plunger 8, and the stroke of the plunger 8 can be set by adjusting the gap t between the plunger 8 and the fixed iron core 9 with the fixed iron core adjusting screw 12 and the nut 13. It is like this. A solenoid coil 10 is provided so as to enclose the plunger 8 and the fixed iron core 9, and when energized, the plunger 8 is attracted and moved in a direction in which the gap t is zero. The spring 11 is attached so as to press the tip of the needle 2 against the nozzle tip 1.

When marking or gluing is performed, a signal voltage is applied to the solenoid coil 10, and the distance between the tip of the needle 2 and the nozzle tip 1 is opened by t according to this signal voltage.
Paint is discharged. A nozzle device using a piezoelectric element instead of the solenoid coil 10 has also been used. FIG. 6 shows an example of a nozzle device using a piezoelectric element. Since the stroke of the piezoelectric element 21 is small, it is enlarged by using the lever 31, and the needle 33 is driven in the vertical direction. The tip of the needle 33 is pressed against the nozzle opening 39 by the spring 35, and the extension of the piezoelectric element 21 raises the tip of the needle 33 to open the nozzle. A tip fitting 23 is provided at the tip of the piezoelectric element 21, abuts against one end of the lever 31, and the rear end is pressed by an adjusting screw 50 and a lock screw 51.

[0005]

In the above-mentioned method, since the valve seat portion of the nozzle tip 1 and the tip of the needle 2 are in shock contact with each one pulse, the needle tip and the nozzle tip valve seat portion are not worn. Occurs. Depending on the paint,
May contain materials that promote wear,
Significant wear occurs with such paints. When such wear occurs, the needle 2 is pressed by the spring 11 and moves to the nozzle tip side, so that the gap t increases. Therefore, the adjustment screw 12 of the fixed iron core needs to be adjusted so as to maintain the gap t at a predetermined value. However, it is difficult to check the wear amount of the needle 2 and the nozzle tip 1 and adjust the gap t to the predetermined value. It was a laborious task.

In the case of a nozzle device using a piezoelectric element, such adjustment occurs as a problem of adjusting the position of the piezoelectric element. Also in the case of the nozzle using the piezoelectric element shown in FIG. 6, the contact portion between the tip of the needle 33 and the nozzle opening 39 is worn. In order to cope with this wear, a gap d is provided between the rear end of the piezoelectric element 21 and the adjusting screw 50 so that the tip of the needle 33 is pressed against the nozzle opening 39 by the spring 35 when the nozzle is closed. By doing this, the lever ratio L1 / L
Until the value obtained by multiplying by 2 reaches d, the tip of the needle 33 when the nozzle is closed and the nozzle opening 39 are pressed by the spring 35 and are in close contact with each other, and no leakage occurs. However, when the gap d is provided, the stroke of the piezoelectric element 21 is reduced accordingly.
Further, every time the value obtained by multiplying the wear amount by the lever ratio L1 / L2 reaches d, the adjustment amount 50 must be set again by the adjusting screw 50 and the lock screw 51.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a nozzle device that automatically operates properly in response to wear of a needle and a nozzle tip fitted thereto. .

[0008]

In order to achieve the above object, the present invention secures one end of a piezoelectric element to a securing means, and adds the amount of expansion and contraction occurring at the other end to one end of a lever supported by a fulcrum. In a nozzle device that transmits to a needle connected to the other end of a lever and opens and closes a gap between a needle tip and a nozzle port to discharge an applied material, the fixing means includes a casing that stores the piezoelectric element, and the casing. Another piezoelectric element which is arranged inside the piezoelectric element so as to expand and contract in a direction perpendicular to the expansion and contraction direction and which is in close contact with the casing and expands with a predetermined force when expanded, and the other piezoelectric element and one end of the piezoelectric element are fixed. The needle is connected to one end of the lever at a substantially right angle and at a rear end rotatably, and is biased by a spring so that the tip is pressed to the nozzle opening. Those were.

Further, a gap adjusting means for adjusting the length of the other piezoelectric element in the expansion / contraction direction and the gap with the casing is provided.

Further, the time constant showing the response of the piezoelectric element drive signal of the piezoelectric element is made larger than the time constant of the other piezoelectric element.

[0011]

When a voltage is applied to the piezoelectric element and the other piezoelectric element, the other piezoelectric element expands and contracts to apply a predetermined force to the casing, and the generated frictional force suppresses the reaction force of the piezoelectric element, so that the piezoelectric element is placed in the casing. It is fixed to the other side, but when no voltage is applied, the other piezoelectric elements can move without coming into close contact with the casing.
The piezoelectric element coupled to this via the fixing portion is not constrained in the expansion / contraction direction. When no wear occurs between the tip of the needle and the nozzle opening, the lever is horizontal when the tip of the needle is pressed against the nozzle opening and the gap between them is zero. When stationary when wear occurs,
Since the tip of the needle is pressed against the nozzle opening by the spring, this lever tilts toward the needle by the amount of wear. When the piezoelectric element and another piezoelectric element are driven in this state, the piezoelectric element expands and contracts with the lever being tilted as a reference. In this way, the tilt of the lever changes according to the amount of wear, and the piezoelectric element expands and contracts based on the state of the tilted lever, so the relationship between the needle tip and the nozzle port is always the same regardless of the amount of wear. The relationship will be adjusted automatically.

By adjusting the lengths of the other piezoelectric elements in the expansion / contraction direction and the gaps with the casing by the gap adjusting means, it is possible to set the frictional force due to the compressive force generated when the piezoelectric elements are extended to withstand the reaction force of the piezoelectric elements. .

When a voltage is applied to the piezoelectric element and another piezoelectric element at the same time, the other piezoelectric element having a smaller time constant expands first to generate a compressive force, and then the expansion of the piezoelectric element causes a reaction. You will bear the power. As a result, the piezoelectric element is always fixed by another piezoelectric element when a voltage is applied.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of an embodiment of the present invention. In the piezoelectric element casing 20, a first piezoelectric element 21 that expands and contracts in the vertical direction and a second piezoelectric element 22 that expands and contracts in the horizontal direction are provided. Each of the piezoelectric elements 21 and 22 is a laminated piezoelectric element and has a cylindrical shape. Yes, when a DC voltage is applied, it extends in the axial direction of the cylinder, and when removed, it returns to its original length. A tip fitting 23 for transmitting the amount of expansion and contraction is attached to one end of the first piezoelectric element 21, and the other end is a hollow cylinder fixed to a fixing member 24 slidably fitted to the second piezoelectric element 22 by an inner cylinder. There is. One end of the second piezoelectric element 22 is in contact with the piezoelectric element casing 20 so as to generate a sufficient frictional force when a force is applied, and the other end of the second piezoelectric element 22 has a gap smaller than the amount of expansion and contraction to the first adjusting screw 25. Facing each other. The first adjusting screw 25 is held loose by a lock screw 26. The first spring 27 presses the first piezoelectric element 21 vertically downward via the fixing member 24 so that the tip fitting 23 does not separate from the lever 31. The set screw 28 presses the first spring 27.

A pulse voltage is applied to each of the piezoelectric elements 21 and 22 from a connector 30 by a lead wire 29. A pulse voltage is applied to the connector 30 from a piezoelectric element drive circuit described later.

The lever 31 has a knife edge 32 as a fulcrum, one end supports the tip fitting 23, and the other end has a needle 33.
The upper spherical portion 34 is rotatably supported. The tip fitting 23 and the lever 31 are knife-edge fitted.
The spherical portion 34 is pressed by the second spring 35. The second spring 35 is urged to press the tip of the needle 33 toward the nozzle port 39, and the pressing force can be adjusted by the second adjusting screw 36 screwed to the nozzle casing 37.

The tip of the needle 33 is pressed against the nozzle opening 39 of the nozzle tip 38 by the pressing force of the second spring 35 to close the nozzle, and the extension of the first piezoelectric element 21 raises the tip of the needle 33 to open the nozzle. The diaphragm 40 constitutes a pressure chamber 41 together with the nozzle tip 38 in a state where the needle 33 can move up and down. A marking device such as paint or ink is supplied to the supply port 42 from a supply device (not shown) at a constant pressure and is discharged from the nozzle port 39 by opening and closing the nozzle.

FIG. 2 shows a piezoelectric element drive circuit which constitutes a nozzle control circuit. A capacitor C is provided in parallel with the first piezoelectric element 21 and has a larger time constant than the second piezoelectric element 22.

The operation of the nozzle device constructed as above will be described. FIG. 3 shows the signal voltage applied to the piezoelectric elements 21 and 22 and the amount of displacement of the piezoelectric elements 21 and 22. Timing and voltage of the signal voltage are determined by the shape or thickness of the marked characters. When such a signal voltage is applied to the lead wire 29 from the connector 30, the piezoelectric elements 21 and 22 expand and contract according to the signal voltage.

When voltage is applied to the first piezoelectric element 21 and the second piezoelectric element 22 at the same time, the second piezoelectric element 22 having a small time constant expands and presses the piezoelectric element casing 20 to generate a compressive force. Next, the first piezoelectric element 21 extends, and the tip fitting 23 pushes down the left end of the lever 31 by the same amount as the extension amount of the first piezoelectric element 21. At this time, the reaction force applied to the first piezoelectric element 21 is the second
The piezoelectric element 22 is opposed by the frictional force based on the compressive force due to the expansion.

The lever 31 has the knife edge 32 as a fulcrum, and the spherical portion 34 is enlarged and pulled up by the lever ratio (L2 / L1), and the needle 33 connected to this is pulled up, and the tip of the needle 33 and the nozzle port 39 are pulled up. The gap is opened so that the marking liquid can be discharged. When the pulse voltage is kept ON for a certain period of time and the voltage is set to 0 V, the first and second piezoelectric elements 21 and 22 are reduced to their original states, and the spherical portion 34 is pushed down by the second spring 35, and the needle 33 is pushed down. At the same time, the diaphragm 40 is also pushed down, the volume of the pressure chamber 41 is rapidly decreased, and the tip of the needle 33 finally closes the nozzle opening 39 while discharging the marking liquid from the gap between the tip of the needle 33 and the nozzle opening 39. The discharging of the marking liquid is stopped.

The above is the operation of one pulse cycle shown in FIG. 3. When this operation is continuously performed, relative movement is performed between the nozzle device and the material to be marked, and a character locus is drawn. Marking as shown in can be performed. Although FIG. 4 shows a case where relative movement is performed so that the respective ejection amounts do not overlap, continuous characters can be drawn by slowly moving.

When the ejection is carried out for a long time as described above, the tip of the needle 33 and the nozzle opening 39 are worn due to frequent contact between the tip of the needle 33 and the nozzle opening 39, and particles included in the marking liquid. Come on. If the first piezoelectric element 21 expands and contracts and the position of the first piezoelectric element 21 does not change when the first piezoelectric element 21 extends and returns to its original position, the tip of the needle 33 completely completes the nozzle opening 39. The marking liquid cannot be blocked, and the marking liquid leaks.

However, the tip of the needle 33 and the nozzle port 3
When 9 is worn, the first and second piezoelectric elements 21, 22
When there is no voltage and there is no extension, no frictional force is generated by the second piezoelectric element 22, and the first and second piezoelectric elements 21, 22
Since the fixing member 24 and the fixing member 24 can move up and down, the needle 33
It is pressed by the second spring 35 until the tip of is pressed against the nozzle port 39. Therefore, the first and second piezoelectric elements 21 and 22 are moved by the lever 31 via the tip fitting 23.
When the fixing member 24 is pushed up and the expansion and contraction of the first and second piezoelectric elements 21 and 22 are started next, the expansion and contraction operation is performed in a state of being fixed to the pushed up position. Therefore, the tip of the needle 33 and the nozzle port 39 that fits with this
Even when the mark is worn, the gap between the tip of the needle 33 and the nozzle port 39 caused by the wear is automatically corrected, and the marking liquid does not leak.

[0025]

As is apparent from the above description, the present invention is provided with the first piezoelectric element for opening and closing the nozzle opening and the second piezoelectric element for fixing the first piezoelectric element only when electricity is applied, and the position of the first piezoelectric element is set to the lever. Since the spring provided on the needle side moves according to the wear between the tip of the needle and the nozzle opening, the marking liquid is prevented from leaking from the gap between the needle tip and the nozzle opening even if wear occurs. be able to.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an embodiment of the present invention.

FIG. 2 is a piezoelectric element drive circuit diagram.

FIG. 3 is a diagram showing a relationship between a pulse applied to a piezoelectric element and an expansion / contraction amount of the piezoelectric element.

FIG. 4 is a diagram showing an example of marking according to the present embodiment.

FIG. 5 is a configuration diagram of a conventional marking nozzle.

FIG. 6 is a structural diagram of a marking nozzle using a piezoelectric element.

[Explanation of symbols]

 20 Piezoelectric element casing 21 First piezoelectric element 22 Second piezoelectric element 23 Tip fitting 24 Fixing member 25 First adjusting screw 26 Lock screw 27 First spring 28 Set screw 29 Lead wire 30 Connector 31 Lever 32 Knife edge 33 Needle 34 Spherical part 35 Second Spring 36 Second Adjustment Screw 37 Nozzle Casing 38 Nozzle Tip 39 Nozzle Port 40 Diaphragm 41 Pressure Chamber 42 Supply Port

Claims (3)

[Claims] 1. A piezoelectric element, wherein one end of a piezoelectric element is fixed to a fixing means, and the amount of expansion and contraction generated at the other end is transmitted to a needle connected to one end of a lever supported by a fulcrum and the other end of the lever, In a nozzle device that opens and closes a gap between a tip and a nozzle port to discharge a coating material, the fixing means includes a casing that houses the piezoelectric element, and expands and contracts in the casing in a direction perpendicular to the expansion and contraction direction of the piezoelectric element. When arranged and extended, the other piezoelectric element that comes into close contact with the casing and compresses with a predetermined force, and the other piezoelectric element and a fixing portion that fixes one end of the piezoelectric element, the needle is the lever of the lever. A nozzle device characterized in that it is connected to one end at a substantially right angle and rotatably at a rear end, and is biased by a spring so that the front end is pressed against a nozzle opening. 2. The nozzle device according to claim 1, further comprising a gap adjusting means for adjusting a length of the other piezoelectric element in a direction of expansion and contraction and a gap between the casing and the casing. 3. The nozzle device according to claim 1, wherein a time constant representing the response of the piezoelectric element drive signal of the piezoelectric element is made larger than the time constants of the other piezoelectric elements.