JPH0282667A - piezoelectric actuator - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a piezoelectric actuator used for operating various devices.

(Ron) Conventionally, as a form of piezoelectric actuator, a plunger that moves in the axial direction, a clamp member that grips the plunger, a piezoelectric element that operates the clamp member, and a stroke piezoelectric element that moves one plunger are used. There is something composed.

(c) Problems to be Solved by the Invention However, the lead wires connected to the piezoelectric plates constituting the piezoelectric element have no copper between the piezoelectric plates (50) as shown in FIG.
(51) is used as an electrode, and from this the external lead wire (
52) It was structured to directly count the numbers.

Therefore, it is difficult to solder the lead wire (52), and the connection part easily comes off.
) could not be increased.

(d) Means for Solving the Problems In the present invention, a piezoelectric element is formed by bonding a large number of ring-shaped piezoelectric plates with a conductive paste, and the same piezoelectric plates are laminated on a printed circuit board, and one end is It is an object of the present invention to provide a piezoelectric actuator characterized in that the curved ends of the lead wires connected to each piezoelectric plate are connected to a printed part on a printed circuit board, and the external lead wires are taken out from the printed circuit board.

(E) Functions and Effects With the configuration described above, the present invention has the following functions and effects.

■The ring-shaped piezoelectric plate that constitutes the piezoelectric element is stacked on a printed circuit board, and the lead wire that connects the base to the piezoelectric plate is connected to the printed part on the printed circuit board, and the external lead wire is connected to the printed circuit board. Since the lead wires can be taken out, it is easy to solder the lead wires all at once on a wide printed circuit board, and the soldering is reliable, so there is no possibility that the lead wires will come off unexpectedly due to vibration etc. It is connected for a long period of time.

■Also, in the conventional type, the lead wire was made by sandwiching a copper foil between the piezoelectric plates, so the strength of the lead wire was weak, and the actuator could stop functioning due to breakage. In the present invention, the lead wires are connected to the printed circuit board by soldering, and then the external lead wires having a larger wire diameter are connected, so that the strength of the lead wires is greatly improved.

■Also. Since the lead wires of the piezoelectric plate are connected to the printed circuit board, the lead wires can be shortened, and therefore the soldering of the lead wires can be automated and the manufacturing stage can be streamlined.

Furthermore, since the lead wires can be connected together on the printed circuit board, the lead wires can be reliably protected.

EXAMPLES The present invention will be specifically described below based on examples shown in the accompanying drawings.

FIG. 1 shows the configuration of a piezoelectric actuator (Δ) according to this embodiment.

As shown in the figure, the actuator (^) is connected to the front and rear walls (a
) (b) cylindrical actuator gauging (
A plunger (d) is mounted concentrically within C) so as to be movable back and forth along the axis, and three piezoelectric elements (e) and (f) are mounted concentrically on the outer peripheral surface of the plunger (d).
It is constructed by arranging the piezoelectric element assembly (B5) consisting of (g).

In addition, in the illustrated embodiment, piezoelectric elements (c) (f) (
g) is supported by the holder ((1), and the holder (
11) Attach the outer periphery to the end face of the front wall (a) with bolts (11°)
It is fixed at.

Then, the piezoelectric element (e) (
[) has a clamping member (k) (J) for clamping the plunger (d) located on the inner diameter part, and
A mounting collar (j) is located on the inner diameter of the central piezoelectric element (g), and the clamp member (k) is placed on the mounting collar.
The base fn+)(n) of (j) is connected. The tips of the clamp members (k) and (j) are divided into an appropriate number of parts by providing slits. (p) is a piezoelectric element ((1
) and (f) is a piezoelectric element mounting plate for clamping.

Next, the operation and specific configuration of each piezoelectric element (e), (f), and (g) will be explained as follows.

That is, the piezoelectric elements (e) and (f) clamp the plunger (d) with a constant clamping force F in the non-energized state,
By applying a positive voltage, it is clamped with a clamping force F+α, and by applying a negative voltage, it is clamped with a clamping force F−α. Note that the clamping force satisfies F-α≧0. That is, even when a negative voltage is applied, the piezoelectric element (e) [f
) will clamp the plunger (d) with a constant clamping force.

On the other hand, when the piezoelectric element ((1) is energized, the piezoelectric element ((1)
) in the axial direction, and in the de-energized state,
The plunger (d) is retracted and its total length in the axial direction is shortened.

The plunger (d) then connects these three piezoelectric elements (
e) A control device (the procedure for applying suppression to (fHg) will be described later)
C), it can be moved in the axial direction.

Piezoelectric elements (e) (f) ((+) are composed of many piezoelectric plates (Q)
It is a cylindrical element formed by laminating in the axial direction of the plunger (d). Electrodes are provided at both ends of the cylinder, and it is configured to expand by applying a voltage to both ends.

Also, in Figure 5, (1) is the actuator (^)
This is a U-shaped or Y-shaped packing with low sliding resistance that is designed to improve watertightness.

In addition, FIG. 5 shows a piezoelectric actuator (
8) shows the configuration of a control device (C) for controlling. As shown in the figure, the control device (C) includes a microprocessor (Ro), an input/output interface (T)fT') consisting of a ^/D, D/^ converter, etc., and the piezoelectric element (e)m( (J) and a memory (Uo) that stores the drive order program, and based on the input signal from the actuator drive button (31) manually input to the control device via the input interface (■), A control signal is generated according to the programmed program, and the control signal is transmitted to each piezoelectric element (c) (f) via the output interface (■°).
(g) to be connected to the hair).

Note that the piezoelectric element piece can be made of, for example, piezoelectric ceramics, and such piezoelectric ceramic pieces include A
PZTCPb (Zr.BO3) is a ferroelectric material with a perovskite crystal structure.

Ti) Oa) system, and P L Z T CP b , L
a (Zr.

A Ti ) Oa ) system, a PT[PbTiO3] system, or a three-component system based on PZT can be used.

Moreover, the piezoelectric element (e) (g) can also be formed by laminating a large number of thin ring-shaped piezoelectric element pieces in the axial direction around the axis of the plunger (d).

Note that in the above configuration, piezoelectric elements (e) (f) (u)
can have not only a circular cross section but also a rectangular cross section, for example, and can also be formed from divided pieces.

Further, the plunger fd) is a clamp member (k) (it
), it has a small coefficient of linear expansion, high hardness, strength, creep resistance, and wear resistance, and has high processing accuracy (1 is preferable; for example, ceramic It can be considered as a material.

In the above configuration, each of the piezoelectric elements (e) (f) ((1
The ring-shaped piezoelectric plate (Q) constituting the piezoelectric plate (Q) has a tapered chamfered part (R) on its outer peripheral surface as shown in FIGS. A conductive paste (P) is applied to the outer circumferential chamfered portion (It), and a lead wire (S) is connected to the chamfered portion (1'l) by soldering.

In Figs. 1 and 2, (v-1) is a printed circuit board for a piezoelectric element (e) for clamping, and while piezoelectric plates (0) are stacked, a lead wire (S-1) is connected to the printed part (w).
) and the piezoelectric element (e) are connected.

(v-2) is a printed circuit board for the stroke piezoelectric element (C1), which is connected to the piezoelectric element ((1)) by a lead wire (S-2).

(X) is an insulating ring provided at the right end of the piezoelectric element (9) for clamping, and (v-3) is the printed circuit board of the piezoelectric element (f), which is connected to the piezoelectric element (f) by the lead wire (S-3). ing.

Then, each of the above printed circuit boards (v-1) (v-2) (v
-3) The printed part (v4) has an external lead wire (So).
is connected.

In addition, the above printed circuit boards (v-1) (v-2) (v-3
), it is desirable to use a ceramic substrate with excellent heat resistance and mechanical strength.

Next, a piezoelectric actuator having such a configuration (^)
Regarding the operation of plunger (d) by
This will be explained with reference to the figures.

When the actuator drive button (31) shown in FIG. 5 is actuated, the control device (C) applies a negative voltage to the piezoelectric element (e) as shown in FIG. A pulsed drive voltage is applied to reduce the clamping force to the plunger (d) to F-α, and a positive pulsed drive voltage is applied to the piezoelectric element (f) to increase the clamping force to F+α. to clamp the plunger (d).

Next, as shown in Fig. 7, when the piezoelectric element ((+)
moves in the direction of the arrow, and accordingly, the plunger (d) clamped by the piezoelectric element (f) or the clamper F1α also moves in the direction of the arrow.

Thereafter, as shown in FIG. 8, a negative pulsed drive voltage is applied to the piezoelectric element ([) to reduce the clamping force to Fα, and a positive pulsed drive voltage is applied to the piezoelectric element (0). Increase the clamping force to F1α and press the plunger (d).
to be clamped. Then, when a positive pulse-like driving voltage is applied to the piezoelectric element (1) and the piezoelectric element (g) is moved in the direction of the arrow.

Next, by repeating the above operation, the plunger (
d) can be moved in a linear manner with a stroke on the order of μm or sub-μmn.

Therefore, when such a piezoelectric actuator (A) is installed in a hot water mixing device (D), which will be described later, etc., the mixing valve can be opened and closed while finely adjusting its opening degree, and an appropriate temperature can be controlled.

Okay, Figure 9 shows the actuator (8) according to this embodiment.
This is an example in which a piezoelectric actuator (A) is applied to an automatic opening/closing valve (D) that functions as a hot water mixing faucet.

In Fig. 9, (10) is a cylindrical box-shaped gauge, and the casing (10) has a
The negative side flow paths (13 and 14) forming two one-side flow paths (13H14) function as a water supply flow path and a hot water supply flow path for the hot and cold water mixing faucet, and their outer open ends are in communication with a water supply pipe (15) and a hot water supply pipe (16), respectively.

On the other hand, the inner open ends of the - side channels (13) and (14) are connected to compartments (17) formed at both ends of the casing (10), respectively.
It communicates with (18).

Also, on the other side wall of the gauging (10), there is a
A T-shaped flow path (20) on the other side is formed.

The other side flow 178 (20) functions as a mixed water flow path of the hot and cold mixer faucet, and its outer open end communicates with the mixed water pipe (21), while its inner bifurcated The open end communicates with the compartments (17) and (18).

Furthermore, in the inner bifurcated opening of the T-shaped cylinder (one),
Valve seats (22) and (23) are provided respectively, and the valve seats (22H23) move back and forth in the axial direction inside the casing (10) to come into contact with and separate from the valve seats (22) and (23), and have an inner bifurcated shape. A valve body (24
) (25) are provided.

Furthermore, piezoelectric actuators (A) are attached to both ends of the gauging (10), respectively.

In each piezoelectric actuator (8), the tip of the plunger (d) can come into contact with the rear part of the valve body (24) (25), so that the valve body (24H25) can be opened and closed.

In addition, in FIG. 9, (30) is a temperature sensor received in the other side flow path (20), which detects the temperature of the mixed water and feeds back the detected value to the control unit as shown in FIG. Then, based on the detected value, the control section operates both actuators (A) of the automatic opening/closing valve by PTD control or the like to perform appropriate temperature control.

The operation of the automatic on-off valve (D) having such a configuration will be briefly explained as follows.

That is, when the detected value from the temperature sensor (30) is fed back to the control section and the control section separately operates both piezoelectric actuators (8) of the automatic opening/closing valve (D) based on the detected value, the valve body (24) and (25) open and close at the set opening degree, and from the - side flow path (13) (14) to the other side flow path (20).
The amount of water supplied and the amount of hot water flowing into the system can be mixed at a fixed mixing ratio.

In this operation, since the valve bodies (24) and (25) are operated by the same actuator (8), flow rate control can be performed more reliably, and appropriate temperature control can be performed more reliably.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional side view of a piezoelectric actuator according to the present invention, FIG. 2 is a cross-sectional view of the main part of the present invention, FIG. 3 and FIG. 4 are perspective views of the main parts of the present invention, and FIG. Fig. 6 to Fig. 8 are explanatory diagrams of the configuration of the control device, Fig. 6 to Fig. 8 are explanatory diagrams of the operating state of the actuator, Fig. 9 is a cross-sectional side view of an automatic on-off valve equipped with the above-mentioned actuator, and Fig. 10 is a perspective view of a conventional type. . (8): Actuator (B): Piezoelectric element assembly C: Control device D: Automatic opening/closing valve e (f) ((]): Piezoelectric element Q: Piezoelectric plate S: Lead wire So): External lead wire ■) Niblint Substrate W) Niblint part

Claims (1)

[Claims] 1) In a piezoelectric actuator in which the piezoelectric elements (e), (f), and (g) are formed by bonding a large number of ring-shaped piezoelectric plates (Q) with conductive paste (P), the same piezoelectric plates ( Q) is stacked on a printed circuit board (v), one end is connected to each piezoelectric plate (Q), and the other end of a lead wire (S) is connected to a printed part (w) on the printed circuit board (v), A piezoelectric actuator characterized in that an external lead wire (S') is taken out from the printed circuit board (v).