JPH01225381A - Micro distance continuous drive type actuator - Google Patents

Abstract

PURPOSE:To insure smooth operation of a plunger as well as its watertightness, by making the plunger move back and forth through a micro distance closed drive system by pulse like voltage and providing a sliding resistance reduced layer between the point of the plunger and the packing of a vent hole located at a casing wall. CONSTITUTION:A plunger 4 is mounted in a casing 3 in such a manner that it is movable back and forth and a packing 14 is fitted by protruding the point 4a of the plunger into a vent hole 7. A sliding resistance reduced layer 5 consisting of a fluorine contained resin mixed with, for example, a specific filler is provided on the surface of the packing or the peripheral surface of the plunger 4a. The plunger 4 is driven by elastic bridges 10 and 11 where piezoelectric elements a and b having elastic diameters and the extensible element c as well as an element are supported. The installation of the foregoing layer 5 makes the plunger operate smoothly and regulates a correct flow rate by applying this device to a fluid valve.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a direct-acting, minute-distance, stepless drive type actuator used for operating fluid pulp and the like.

(B) Prior Art Conventionally, there are various types of actuators for opening and closing fluid pulp, etc., such as those operated mechanically, those operated electrically, and those operated by fluid.

The actuator stores the plunger in the actuator casing so that it can move forward and backward, and the tip of the plunger is inserted into the insertion hole provided in the front wall of the casing in a protruding manner to the outside, so that the tip moves forward and backward. The opening/closing operation of fluid pulp etc. can be performed in conjunction with the above.

Moreover, a packing is provided on the circumferential surface of the insertion hole so as to closely fit the circumferential surface of the tip end of the plunger to improve the watertightness within the actuator casing.

(c) Problems to be Solved by the Invention However, the above actuator had the following problems.

■ Conventional actuators do not allow highly accurate positioning, make delicate opening/closing adjustments of fluid valves difficult, and are mechanically complex, making it difficult to make them compact.

■There is a problem in that smooth operation of the plunger cannot be ensured because there is a large frictional resistance between the tip of the plunger that moves forward and backward and the gasket that is in close contact with the tip.

■As the seal wears heavily, the seal becomes less watertight, impairing the functions of actuators, etc., and requires frequent maintenance.

■In order to improve the slidability of the tip of the plunger, it is necessary to apply grease to the circumferential surface of the tip and the surface of the gasket, so there is a problem that a separate grease application process is required, and the grease is cheap. Therefore, there was a problem in that the manufacturing cost was high. Moreover, there was also the problem that the effect of the grease was not permanent.

■In the case of inchworm actuators, the clamping part of the plunger must have a large coefficient of friction, so grease is applied to the tip of the plunger, which is the sliding part, and the grease is applied to the clamping part of the plunger. If this occurs, there is a risk that the basic functions of the actuator may be impaired.

(d) Means for Solving the Problems In this invention, a plunger that can be driven steplessly over minute distances by pulsed voltage is housed in the actuator casing so as to be movable forward and backward, and the tip of the plunger is
A gasket is inserted in a protruding manner to the outside into an insertion hole provided in the front wall of the actuator casing, and is closely attached to the circumference of the proximal end of the plunger along the circumference of the insertion hole to improve watertightness inside the actuator casing. A micro-distance stepless drive type actuator, which is provided with a sliding resistance reducing layer on at least one of the surface of the packing or the peripheral surface of the tip of the plunger to reduce the sliding resistance of the tip. We aim to provide the following.

In addition, here, micro-distance stepless drive actuators include laminated piezoelectric actuators, piezoelectric bimorph actuators, stepping linear motors, piezoelectric linear motors, ultrasonic linear motors, combinations of ultrasonic motors (rotary type) and rotating screws, and stepping motors. (rotary type) and a combination of a rotating screw, etc.

(e) Action/effect This invention provides the following effects.

■Actuator operation, that is, plunger movement 9
Since the operation is a minute distance stepless drive using a pulsed voltage, the plunger can be moved forward or backward depending on the order of the number of voltage applications, and the mechanism is simple and compact, making it suitable for fluid valves and other various devices. , the machine can be operated precisely.

■Since a sliding resistance reduction layer is formed on at least one of the surface of the gasket or the peripheral surface of the tip of the plunger to reduce the sliding resistance of the tip, the friction between the gasket and the tip of the plunger is reduced. This reduces resistance and allows the plunger to operate smoothly and with high precision.

■Since there is less wear on the packing, it is possible to maintain good watertightness by the packing, and the function of the actuator etc. can be ensured well, and the frequency of maintenance of the packing can be reduced.

- Since it is possible to provide a sliding resistance reducing layer that is cheaper and more durable than grease, it is possible to reduce manufacturing costs, ensure permanence, and ensure smooth operation of the plunger.

■Since it does not stick to the clamp part of the plunger like grease, the basic functions of the actuator can be maintained in good condition.

(f) Example An example of the present invention will be described in detail based on the drawings. Fig. 1 shows a cross-sectional view of a piezoelectric actuator (^) which is one form of a minute distance stepless drive type actuator according to the present invention. A plunger (4) is installed concentrically in a cylindrical actuator casing (3) having front and rear walls (1) and (2) so as to be movable back and forth along the axis. The tip (4a) is formed to have a stepped small diameter, and the tip (4a) is an insertion hole (4a) provided in the front wall (1).
7) It is inserted into the inside in a protruding manner to the outside.

A recess (1a) for attaching the gasket is provided in the front wall (1) along the opening surface of the insertion hole (7).
a) The packing (14) is installed inside.

The packing (14) is made of rubber, synthetic resin, or other watertight elastic material and is formed into a seven-figure shape.

Moreover, as shown in Figures 2 and 3, Patsukin (1
4) on the insertion hole (7) side, that is, the plunger (
4), or on the circumferential surface of the tip (4a) of the plunger (4).
Sliding resistance reduction layer (5) to reduce the sliding resistance of a)
) is formed.

As the sliding resistance reducing layer (5), preferred chemical materials such as fluorine-containing resin, nylon, polyoxymethylene, tetrafluoroethylene, polyethylene, and silicone, which have low friction, low abrasion, and high chemical resistance, are used. and physical properties.

In addition, the above-mentioned fluorine-containing resin includes a compound obtained by adding a special filler to tetrafluoroethylene resin, and the special filler is softer than the mating material it comes into contact with, has less wear, and does not wear out the mating material. Linear expansion coefficient is 9.0x107
℃, such as polyimide resin, carbon, graphide, etc., can be used.

Moreover, the fluorine-containing resin can be formed into a sheet, the surface of which can be chemically treated with an ammonia solution of metallic sodium, etc., and the sheet can be bonded with an adhesive (epoxy type) for fluorine-containing resins.

Furthermore, it is better to apply the above-mentioned fluorine-containing resin sheet not only to the area in contact with the other material, but also to the surrounding area, since the sheet will be less likely to peel off. Of course it's a good thing.

Therefore, the sliding resistance reducing layer (5) can improve the low friction, low abrasion, chemical resistance, etc. of the circumferential surfaces of the tips (4a) of the packing (14) and the plunger (4). can.

Note that an elastic body (6) having sealing properties such as silicone rubber is provided at the tip of the plunger (4).

Furthermore, as shown in Fig. 1, piezoelectric elements (a) and (b) whose diameter can be freely contracted and expanded, and a piezoelectric element (C) which can be expanded and shortened are arranged on the outer circumferential side of the plunger (4). has been done.

That is, the piezoelectric element (C) is disposed in the center of the plunger (4), and is cantilevered by a cylindrical one-side holder (9) with an abbreviated cross-section whose base end is fixed to the actuator casing (3). supported by the state.

(9') is a cylindrical other side holder with an abbreviated cross-section fixed to the tip of the piezoelectric element (C), and supports the piezoelectric element (b) via a rear elastic bridge (11), which will be described later. ing.

Moreover, another piezoelectric element (a) (b) is a plunger (4)
The front and rear elastic bridges (1G) (11) are supported at the front and rear ends of the front and rear elastic bridges (10) (
11) is a cantilever whose base end is attached to the inner peripheral surface of each holder (909°) in a vertically overlapping state, and whose tip extends toward the front and rear walls (1) and (2) of the actuator casing (3). A piezoelectric element (a) is formed on the outer peripheral surface of the tip.
(b) is fixed, and brake shoes (12) and (13) are fixed to the inner circumferential surface of the tip.

Moreover, the front and rear elastic bridges (10) and (11) are arranged so that the piezoelectric elements (a) and (b) are reduced in diameter and the plunger (
4) When clamping from the outer periphery, a certain length is required to maintain a certain deflection performance, but each bridge (10)
(11) is attached to the inner peripheral surface of each holder (9) (9') in an overlapping state, so that each bridge (10)
The piezoelectric elements (a) and (b) fixed to the tip of (11) can be brought as close as possible to the piezoelectric element (C).

Therefore, in order to be able to assemble the piezoelectric elements (a), (b), and (c) compactly as described above, the plunger (4) is also made as short as possible, and the piezoelectric actuator (^)
The device itself can be made more compact.

The piezoelectric elements (a) (, b) are configured to shorten when they are in a energized state, and the piezoelectric elements (C) are shortened when they are in a non-energized state.

That is, the piezoelectric elements (a) and (b) shorten when energized, reducing the inner diameter and clamping the plunger (4) from the outer periphery, and expand and expand the inner diameter when not energized. diameter to release the clamp on the plunger (4).

On the other hand, when the piezoelectric element (C) is energized, it extends in the axial direction on the plunger (4), and when it is not energized, it shortens the upper part of the plunger (4) and extends in the axial direction. This will shorten the overall length.

Then, the plunger (4) connects these three piezoelectric elements (
By controlling a), (b), and (c) appropriately, it is possible to move forward and backward in the axial direction.

The piezoelectric elements (a), (b), and (c) are cylindrical elements formed by laminating a large number of piezoelectric element pieces in the axial direction of the plunger (4), as shown in FIGS. 1 and 4. , electrodes are provided at both ends of the cylinder, and the cylinder is configured to contract and expand in diameter by applying a voltage to both ends.

Note that piezoelectric ceramics can be used as the material of the piezoelectric element pieces, for example, and such piezoelectric ceramics include:
ABO3 is a ferroelectric material with a lobskite crystal structure, such as PZT [Pb (Zr, Ti)Oal system,
PLZT [Pb (Zr.

Ti)03], PT[PbTiO3] system, or p
A three-component system based on z'r can be used.

Moreover, the piezoelectric elements (a), (b), and (c) are formed by laminating a large number of thin ring-shaped piezoelectric element pieces in the axial direction around the axis of the plunger (4), as shown in FIG. You can also do that.

In this case, the direction of voltage application is changed by 90 degrees.

Note that in the above configuration, piezoelectric elements (a), (b), and (C)
can have not only a circular cross section but also a rectangular cross section, for example, and can also be formed from divided pieces as shown in FIGS. 6 and 7.

In addition, the main xylem of the plunger (4) is plexi s −
(12) (13) Via piezoelectric elements (a) (b) (c)
Because it is clamped many times, it has a large friction coefficient unlike the sliding/moving parts at the tip, and also has a small coefficient of linear expansion, and has high hardness, strength, creep resistance, and wear resistance1, making it easy to process. It is desirable to use a material with high precision; for example, a ceramic material may be used.

Further, FIG. 8 shows the configuration of a control device (C) for controlling the piezoelectric actuator (A). As shown in FIG.
), an input/output interface (S) (1), and a memory (U) that stores a drive order program for the piezoelectric elements (a), (b), and (c).

Next, the movement of the plunger (4) by the actuator (A) having such a configuration will be explained with reference to FIGS. 9 to 12.

When the actuator drive button (U) shown in FIG. 8 is pressed, the control device (C) drives the piezoelectric element (a) as shown in FIG.
), and the voltage is the same.

By expanding the diameter of the electronic element (a), the plunger (4
), the plunger (4) is clamped by applying a voltage to the piezoelectric element (b) and reducing the diameter of the piezoelectric element (b).

Next, as shown in FIG. 10, when the voltage application to the piezoelectric element (C) is released and the piezoelectric element (C) is shortened, the piezoelectric element (C) moves in the direction of the arrow, and Accordingly, the plunger (4) clamped by the piezoelectric element (b) also moves in the direction of the arrow.

Thereafter, as shown in FIG. 11, a voltage is applied to the piezoelectric element (a) to reduce the diameter of the piezoelectric element (a), thereby clamping the plunger (4) and increasing the diameter of the piezoelectric element (b). By removing the voltage application and expanding the diameter of the piezoelectric element (1), the clamp on the plunger (4) is released.

Next, as shown in FIG. 12, when a voltage is applied to the piezoelectric element (C) and the same piezoelectric element (C) is expanded, the piezoelectric element (C) moves in the direction of the arrow, and along with this, the piezoelectric element (C) moves in the direction of the arrow. Plunger (
The piezoelectric element (b) whose clamp is released in 4) also moves in the direction of the arrow.

After that, by repeating the above operation, the plunger (
4) can be moved in a linear manner with a stroke on the μm order or sub-μm order, and various actuating devices connected to the tip (4a) of the plunger (4) can be precisely operated. become.

In this case, the micro-distance stepless drive actuator refers to a laminated piezoelectric actuator, a piezoelectric bimorph actuator, a stepping linear motor, a piezoelectric linear motor, an ultrasonic motor (a combination of a rotary motor and a rotating screw,
A combination of a stepping motor (rotary type) and a rotating screw.

Next, to explain an application example of the actuator (8) according to this embodiment, the one shown in FIG. 13 has a structure applied to a valve for performing flow rate HM and water stop as a single channel valve. The actuator casing (3) includes:
In the direction of the tip of the plunger (4), the valve case (1
6) are connected in series, the valve case (16) is bent into an abbreviated shape, and one side is connected to the water inlet [17].
, the other is a water outlet (18), and the flow path (I4) from the water inlet (17) to the water outlet (18) is formed in an abbreviated shape along the valve case (16), and the flow path (I4) is formed in an abbreviated shape along the valve case (16). A valve body (19) made of a diaphragm valve is disposed in the curved portion.

The tip (4a) of the plunger (4) can freely come into contact with the rear wall of the valve body (19), and as the plunger (4) advances and retreats, the valve body (19) opens and closes the flow path (the old opening and closing). is configured to do so.

(20) is a water inlet channel that communicates with the water inlet (17);
21) is a water outlet communicating with the water outlet (18);
(22) is a partition interposed between the water inlet channel (2G) and the water outlet channel (21), and (23) indicates a valve receiver formed at the base of the water outlet channel (21).

The valve receiver (23) has a valve body (1) made of a diaphragm valve.
9) can be press-contacted and separated, and when the plunger (4) advances, the valve body (19) is pressed from the rear wall, and the valve body (19) is attached to the valve receiver (23) based on the function of the diaphragm valve.
9) is pressed into contact with the valve body (19), and the base of the water outlet channel (21) is pressed against the valve body (19).
) and the flow path is blocked.

On the other hand, when the plunger (4) is operated to retreat, the tip (4a) of the plunger (4) separates from the pilot hole of the diaphragm valve, and the valve body (19) moves toward the valve receiver (23) based on the function of the diaphragm. ) away from the outflow channel (21
) is opened and the flow channel (formerly) is opened, and water from the water inlet (17), which can also be operated to shut off the water by blocking the flow, flows out from the water outlet (18). .

In addition, the forward and backward movement range of the plunger (4) is controlled by the action of the piezoelectric elements (a), (b), and (c) of the actuator (^).
By adjusting the opening degree of the valve body (19), the amount of water flowing can also be adjusted.

Moreover, the one shown in Fig. 14 shows the case where it is used as a mixing path valve in a hot water mixing faucet, and is used for temperature adjustment,
This figure shows an example in which the actuator (^) of this embodiment is applied to a mixing faucet valve that performs water flow adjustment and water shutoff functions.

That is, the actuators (A) (A) are disposed on the left and right sides facing each other, and a mixing faucet valve case (24) is interposed between them, and in the valve case (24),
Plungers (4) of left and right actuators (A) (^)
) (4), a valve body (19) (19°) consisting of a diaphragm is arranged facing left and right at the tip of the valve body (19).
9) (19”) is disposed so as to be able to press against and separate from the opening edges at both ends of the cylindrical mixing water tank (25) interposed therebetween, so that the opening edges at both ends of the mixing water tank (25) are connected to the left and right sides. Valve receptor (23)
(23°).

The openings at both ends of the mixed hot water and water cylinder (25) are connected to the left and right valve bodies (1
9) (19°), the water inlet flow path (26) and the hot water entry flow path (27) are connected to each other through the - pipes. It is partitioned by a central partition wall (28), and a mixed hot water channel C29) is communicated with the central part of the mixed hot water f@(25).

Therefore, the piezoelectric elements (a) (b) of the actuator (^)
The left and right valve bodies (
19) (19°) opens and closes the valve receiver (23) (23°), or adjusts the degree of opening and closing, and connects water from the water inlet flow path (2e) and hot water from the hot water flow path (27). , the hot water flows into the mixed hot water cylinder (25) at an appropriate adjustment ratio, and the hot water flows out from the mixed hot water flow path (29), and the valve body ( 23) can adjust the temperature by adjusting the amount of water and hot water from the water inlet flow path (26) and the hot water input flow path (27), and can also adjust the overall amount. The body (23) is closed.

The embodiment of the present invention is constructed as described above, and the following effects are produced according to the embodiment.

■The plunger (4) is actuated by the piezoelectric elements (a), (b), and (c), and the tip (4) of the plunger (4)
a) A sliding resistance reduction N (5) is applied to the circumferential surface or the surface of the gasket (14) that is in close contact with the circumferential surface of the tip (4a) in order to reduce the sliding resistance of the tip (4a). Because of this, the plunger (4) can be moved forward and backward with precision, and the mechanism can be simplified and made more compact.

(2) When the piezoelectric actuator (8) having such a configuration is applied to a valve that requires operations such as temperature adjustment, flow rate adjustment, and water shutoff, temperature and flow rate adjustments can be made accurately.

■Since there is less wear on the packing (14), the packing (14) has less wear.
14) can be maintained well, the function of the piezoelectric actuator (A) can also be ensured well, and the frequency of maintenance of the seal (14) can be reduced.

■Since it is possible to form a sliding resistance reducing layer (5) made of fluorine-containing resin, etc., which is cheaper and more durable than grease, it reduces manufacturing costs, ensures permanence, and reduces plunger (
4) smooth operation can be ensured.

(2) Since the sliding resistance reducing layer (5) does not stick to the clamp part of the plunger (4) like grease, the basic functions of the piezoelectric actuator (8) can be ensured well.

[Brief explanation of the drawing]

FIG. 1 is an explanatory cross-sectional view showing the actuator of the present invention, FIG. 2 is an enlarged partially cutaway cross-sectional view of the tip of the plunger, and FIG.
The figure is an enlarged view of the packing, Figure 4 is a sectional view taken along the line I-I in Figure 1, Figures 5 to 7 are illustrations of other specific examples of piezoelectric elements, and Figure 8 is an explanation of the configuration of the control device. Figures 9 to 12 are explanatory diagrams showing the operating sequence of the actuator of the present invention, Figure 13 is a cross-sectional explanatory diagram of a single channel valve to which the actuator of the present invention is applied, and Figures 1 and 4 are illustrations of the present invention. FIG. 2 is a cross-sectional explanatory diagram of a valve for a mixing path to which the actuator of the invention is applied. (8): Piezoelectric actuator (a) (b) (c): Piezoelectric element (1): Front wall (2): Rear wall (3): Actuator casing (4) Nib plunger (5): Sliding resistance reduction layer ( 7): Insertion hole

Claims (1)

[Claims] 1) Inside the actuator casing (3), there is a plunger (4) that can be driven steplessly over minute distances using pulsed voltage.
The plunger (4) is inserted into the insertion hole (7) provided in the front wall (1) of the actuator casing (3) so as to protrude outward. The plunger (4) is inserted along the circumference of the insertion hole (7).
) is provided with a packing (14) that is in close contact with the circumferential surface of the tip (4a) of the actuator casing (3) to improve the watertightness inside the actuator casing (3), and the surface of the packing (14) or the plunger (4
) is formed with a sliding resistance reducing layer (5) on at least one of the circumferential surfaces of the tip (4a) to reduce the sliding resistance of the tip (4a).