JPS62189979A - Piezoelectric actuator - Google Patents

Abstract

PURPOSE:To simplify and miniaturize a construction, to contrive to reduce power consumption and to eliminate an electromagnetic noise by applying voltage selectively to piezoelectric elements, making locking and expansion mechanisms operate respectively by the electrostriction of said piezoelectric elements and moving a rod axially in an inching movement. CONSTITUTION:The expansile and contractile force of a piezoelectric element 32 in case of application of voltage thereto is such that moves a holder 11 to the left side along the central axis of a rod 50 against the elastic force of a spring 12. The expansive force of piezoelectric elements 112 and 212 in case of application of voltage thereto acts so as to lock a movement of the rod 50 against holders 11, 21 in the direction of the central axis. The application of voltage selectively to the piezoelectric elements 32, 112, 212 moves the rod 50 axially in an inching movement.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention is configured to move a rod by using the electrostrictive action of a piezoelectric element to drive an object connected to the rod. Regarding the piezoelectric actico J-Yu.

(Prior Art) As is well known, in the past, many actuators for operating various working mechanisms to be driven have applied so-called electromagnetic action such as solenoids and electromagnets.

(Problems that the invention attempts to solve) However, in this type of conventional Akujiko J-Yu, a. The structure is complicated.

b. The size is large and the power consumption is large.

C0 Generates electromagnetic noise.

The if degree of d0 positioning is low.

There were various problems such as.

(Means for Solving the Problems) In the present invention, in order to solve the above problems, the first piezoelectric element L'11 is arranged in the center of the rod. A second piezoelectric element is housed in a first hole that is in contact with the end of the first piezoelectric element, and is applied to the second piezoelectric element that is held in the first hole. , a first lock R structure that fixes and covers the movement of the rod in the axial direction with respect to the first holder by being displaced in a direction intersecting the axial direction; and Electrostrictive action in the axial direction of the rod by a third piezoelectric element housed in a second holder in contact with the right end of the element and attached to the rod by t1 intersects with the axial direction. by displacing the second holder in the direction
The second [1] fixes the movement of the rod in the axial direction.
Once the bolt of either the first or second holder is fixed so that it cannot move in the axial direction of the Jrad, the other holder is fixed to the telescopic mechanism. The spring force that moves in the axial direction of the [] tube following the expansion and contraction action of 11! 5. Elasticity (J-'j is the first, second, and third) 3.11-The structure includes a drive circuit that selectively applies a voltage to the electric element. .

[Function] In the piezoelectric actuator having such a configuration, the first. Second. A voltage is selectively applied to the third piezoelectric element, and the electrostrictive action of the third piezoelectric element causes the telescopic structure and the first
．． By activating each of the second locking mechanisms, the rod is moved in the axial direction in a shakudori east manner.

(Example) Hereinafter, an example of the present invention will be described in detail based on the accompanying drawings.

FIG. 1 shows an embodiment of a piezoelectric actuator according to the present invention, and FIG. 1(a) is a sectional view, and FIG. 1(b) is a sectional view.
shows a side view, respectively.

At d3 in FIG. 1, the main body of the piezoelectric actuator has brackets 1 to 10 and 20 and spacers 30 at the top and bottom.
and 31 are placed on both sides, and the spacer l-10 and the spacer 30. Bracket 1-20 and bracket l-10, spacer 31. The guide pins 40 and 41 are inserted into the bracket 20, and both i'lry
+ to put 1~/12.713 and nara h/14.4
Tighten with 5.''
, 31, the brackets 1 to 31
It has a structure in which 10 and 20 are fixed.

Further, a cylindrical hole is formed passing through the central part of the brackets 1 to 10 and 20 in the direction of the central axis of the guide pin /'lo, 4.1. The spacers 30 and 31 are attached to the brackets 10 and 20.
A movable part as shown below is constructed through the space formed in between.

J, the central axis of the cylindrical hole is the same as the guide pin 40.
4.1, the axis U is aligned at J:, and the rod 50 is located at the central axis.

In other words, the central axes of each of the cylindrical holes and the 1] tube 50 coincide with each other.

Further, a piezoelectric element 32 is disposed at the center of each rod 50, and holders 11 and 21 are disposed on the left and right sides thereof in contact with both ends of the piezoelectric element 32.

Here, the holder 11 is! 1iJ As described above, the brackets 1 to 10 are slidably accommodated in the cylindrical holes formed therein, and the r end of the bracket is connected to the screw 13 via the spring 12.
It is held in place by a screw thread into the cylindrical hole.

On the other hand, the holder 21 is accommodated in a cylindrical hole formed in the bracket 20, and its right end is held by a screw 23 screwed into the cylindrical hole through a spacer 22.

Incidentally, the axial alignment of each cylindrical hole and the central axis of the rod 5o described above is achieved by the screwcoats 13 and 23.

Further, inside the holder 11, there are a screw 110, a spacer 111, and a spacer 111, which are separated and independent from each other around the rod 50. Piezoelectric cord 112. Spacer 113. ■Fuji 114, 115. Sets 1 to 116 are respectively embedded in the inner circumferential surface of the holder 11 so as to be able to slide freely.

Here, one end surface of the wedge 114 is formed as four parts in the shape of a truncated cone, and conversely engages with the groove 11 of the wedge 115, which is formed as a convex part on the base of a circle.

Further, the screws 1 to 1164 screwed onto the inner circumferential surface of the holder 11 can be moved to the right by rotation around the eye 50, and the piezoelectric element 112 can be moved to the right as will be described later. When no voltage is applied to 11111.Scrico 110.Sveza 111.J piezoelectric element 1
12. The spacing 1)-113 and the wedges 114 and 115 are in close contact with each other in the holder 11, and in this state, the rod 50 is screwed (ff
The position has been adjusted.

Incidentally, when viewed from the piezoelectric element 32, the structures inside the holder 11 and )r which are symmetrical to each other are the respective scratch bars 210. spacer 211, LF electric wire 212. Spacer 213. Wedge 21/I, 215. The cellar 1 to the screw 216 are also configured inside the holder 21.

In this way, in the piezoelectric actuator 1-1 of the present invention, the entire movable part is connected to the
and 20, of which holder 11 is always stressed to the right by a spring 12.

The piezoelectric element 32 (the piezoelectric elements 112 and 212 are similarly constructed) used in such a piezoelectric actuator having the @ structure has a hole 320 in the center as shown in FIG. 2, for example.
A thin disk [made of a piezoelectric material such as barium titanate (BaCO3)] 3 has a notch 321 on the circumference that is perpendicular to the straight line 2 passing through the center of the chain hole 320.
A laminate 323 is constructed by laminating a large number of 22, and an electrode 325 extending in the lamination direction is arranged on a flat part 324 formed in the laminate 323 by the notch 321 of each disc 322. It has an established structure.

In the piezoelectric cord 32 of N construction, when a predetermined voltage is applied to the electrode 325, the laminate 323 is distorted according to the voltage, and in the mounted state as shown in FIG.
The piezoelectric element 32 extends in the direction of the central axis of the rod 50.

At this time, the movement of the holder 21 in the direction of the central axis of the rod 50 is fixed by screwing the screw 23 into the cylindrical hole of the bracket 1-20 via the spacer 22, as described above.

Therefore, the stretching force of the voltage water droplet 32 when voltage is applied is applied to the holder 11, and the boulder 11 is moved by the spring 1.
The rod 50 acts against the spring force No. 2 to move the rod 50 to the left along the central axis [action (2)].

On the other hand, the piezoelectric element 112 mounted in the boulder 11 expands in the direction of the central axis of the rod 50 by receiving the voltage applied as described above.

At this time, the right end of the piezoelectric element 112 is connected to the screen 1 through the spacer 111. -110, the above-mentioned stretching force of the piezoelectric element 112 when voltage is applied is space + J
113 to the left side of the piezoelectric element 112, and brings the wedges 114 and 115 into contact with Lt with stress in the direction of the central axis of the rod 50.

Here, the two bolts 114 and 115 are engaged by the concave end face and the convex end face formed in a truncated cone shape as shown in the previous item (e), so that the central axis of the rod 50 due to the pressure welding is The stress in the direction is changed by the wedge 114 into a direction perpendicular to the central axis direction.

Due to this stress, a tightening force from the J Fuji 114 is applied to the outer circumference of the rod 50 and the inner circumference of the holder 11.
Movement of the rod 50 in the central axis direction with respect to the holder 11 is locked.

Similarly, in the holder 21, the voltage applied to the piezoelectric element 212 mounted in the holder 21 (the tension force in the direction of the center axis of the pull rod 50 is applied in the direction of the center axis through the wedge 214). The rod 50 is displaced in a direction perpendicular to
and the holder 21, and movement of the rod 50 relative to the holder 21 in the central axis direction is locked.

In this way, the stretching force of the piezoelectric cords 112 and 212 when voltage is applied is
The force of the force of the force of the force of the force of the force of the force of the force of the force of the force of the force acting on the rod 50 against the holders 11J3J and 21 is as described above. It is possible to adjust it depending on the right position.

Next, FIG. 3 shows the configuration of a drive circuit 60 for a piezoelectric actuator according to the present invention, and FIG. The operation will be explained with reference to 3. First, before the fjj operation of this LF electric actuator, when the polarization switch 61 is operated, the operation will be followed by a steady signal from the driver 69. '1 is element 112, 32°2
12, a predetermined polarization type L" is stamped hl+, and the piezoelectric elements 112, 32, 212 are subjected to a so-called polarization process.

This polarization process Pv is an indispensable process for stabilizing the electrostrictive behavior of the piezoelectric elements 112, 32, 212 with respect to the electric currents 1 and 1 applied thereafter.

Next, when the starting switch 62 is operated by the piezoelectric actuator to move the rod 5o, the OR circuit 6
The gate 5 is released, and the clock CK as shown in FIG. is input.

If, for example, forward counting is selected by the count direction selection switch 63, the IJ/D counter 66 will output the clock C.
K is successively divided into 1/2.1/4.1/8, and frequency-divided pulses Q1 . Q2. Q3 yells.

This frequency divided pulse Q1. Q2. Based on Q3, the U/D counter 66 repeatedly counts the clock CK from 0 to 7, and uses the count 1 to 7 as an address command to a read-only memory (hereinafter abbreviated as ROM) 67. Manpower.

The ROM 67 has addresses O to 7 as shown in FIG.
Ni, D, D3 (-T piezoelectric elements 112, 32, respectively)
212 (corresponding to the voltage application side CII), and from the U/D counter 66 to IJ
Every time the CK of the CK is input, the data D of the address is 3.1, - for the corresponding column i~11〆1. , Dl, 1) 2 in Figure 4(C).

They are output in parallel in the manner shown in (f) and (q).

The output data []. , D1. D2. is input to a driver 69 through a D-flip-flop (hereinafter referred to as D-FF and 18-Lee) 68, and the driver 69 inputs this data D. , D, and D2, a predetermined control voltage is applied to the piezoelectric elements 112, 32, and 212 that have been polarized as shown in the previous 3 d. .

Under such control, the piezoelectric acticoator performs the operation shown in J's F corresponding to counts O to 7 of the clock CK.

(Karan l-0) Do, D2 becomes "')-bilbel, and piezoelectric element 112
．． A voltage is applied to 212, and the movement of the rod 50 in the central axis direction is locked with respect to the holders 11.21 on both the left and right sides by the above (action (2)).

(Count 1) When the 02 force reaches the "j" level, the I lower type element 2'I2 is released, and the II socket of the (-] TRADO O against the holder 21 is released.

(Count 2) Dl goes to "H" level, a voltage is applied to the piezoelectric element 32, and the above (action (■)) is applied to the holder 11.

In other words, the holder 11 is moved toward the 62nd side against the rightward stress of the spring 12.

At this time, the rod 50 is still locked to the holder 11, so it follows the movement of the holder 11 and
-Moved to side.

(Tsunoran 1-3) [] 2 also becomes ``1-Billbel'', voltage is applied to the electric FEE Kiko 212, (Karan 1-2) and the rod 50 moves to the h- side, or the above [action (■)] ”, it is locked again to Revolk 21.

(Count 4) Do becomes the iiL u level, and the piezoelectric element 1''I2 is discharged, so that the locks 1 to 1 against the holder 11 are
``50 L'' is divided by fk.

(Karan t-5, 6) 1] 1 also becomes the "l" level, the bar wire 32 is discharged, and several sets i11 move toward the center axis of the rod 50.

At this time, the lock of the lrad 50 relative to the holder 11 which had been moved to the side is released, so that the holder 11 absorbs the rightward stress of the spring 12 due to the contraction of the piezoelectric body 32. The receiver 11 is moved to the right and returned to its original position.

On the other hand, since the rod 50 is locked with respect to the holder 21, it cannot be moved even when the holder 11 is returned to its original position.

Therefore, when this state is viewed from the holder 11, the rod 50 has been moved to the 1 side by the extension of the moon-denki 32.

(Count 7) One. Also “'I do I novel roar, (1 telecomment, 112
An electric current j1 is applied to ゜212, and the holder 11.21 is returned to the state of (Karan l-0) by the 1-notation (action ■)!] rad 0 is turned 1 to 8.

In this way, each time the clock CK rotates one turn in the forward direction, the rod 5 is moved by an amount corresponding to the extension of the L" type element 32.
It becomes possible to move the rod 50 to the side of 0, and if such control is repeated, the rod 50, which is
It can be moved to the i side.

During this movement, the rod 50 is always locked by one of the right holders 11.21, so even if a certain amount of force is applied to the rod 50 in the right direction, that force will If the force is less than the tension force of the piezoelectric cord 32 minus the tension force of the spring 12,
The rod 50 cannot be moved to the left.

When moving the rod 50 to the right, select the count h selection switch 63 to advance the JJ count of the tJ ID counter 66 in the opposite direction, and set If the cheeks D, 101, 02 are outputted from the corresponding address of the ROM 67 so as to be opposite to the timing cutout 'V-1~ mentioned above.

In this case, whether to start or stop the movement of the rod 50 to the left or right can be selected using the start switch 62.

Note that [the force for moving the rod 50 to the right side is exerted on the rod 50 when the rod 50 moves to the right side because it is generated by the tension force of the spring 12]
The force 1 in the direction of the r-button must be less than or equal to the tension force of the spring 12.

The tension force of this spring 12 is
7 can be achieved by adjusting and overturning.

By the way, the drive circuit 60 in FIG.
The moving speed of the piezoelectric element 32 is determined by using a microcomputer, etc. instead of the oscillator 64, and applying a clock pulse of an arbitrary frequency to calculate the time per cycle involved in the expansion and contraction of the piezoelectric element 32. In other words, the moving speed of the rod 50 may be arbitrarily set according to the clock pulse frequency.

In addition, this type of piezoelectric element 32 can freely set the extension length per cycle by making the application type LF variable, thereby making it possible to make the moving speed of the mouth rad 50 variable and positioning. The accuracy will be improved and you will be able to avoid errors.

In the piezoelectric actuator of the present invention, the piezoelectric element 112.3 is used in consideration of miniaturization, power saving, and drive efficiency.
2. In 212, an example using a cylindrical laminated type as shown in FIG. 2 has been described, but it goes without saying that a simpler shape such as a rectangular parallelepiped can also be used.

[Effects of the Invention] As explained below, according to the piezoelectric actuator 1-2 of the present invention, one side of each locking mechanism of the rod is made of left and right piezoelectric elements penetrated into the rod, and the other side is fixed. is disposed so as to be movable in the axial direction of the rod by an expansion/contraction mechanism consisting of another piezoelectric element provided at the center of each of the locking mechanisms, and a voltage is selectively applied to each of the piezoelectric elements to reduce its electrostrictive effect. By making the locking mechanism and the telescoping mechanism work respectively, the rod can be moved in the axial direction (left and right) in a horizontal manner, which simplifies and downsizes the structure and saves power consumption. The result is 1! The electromagnetic radiation 18 is divided by 4''1, and in particular, it has various excellent advantages such as increasing the degree of high fi'j degree ff' (determination is increased by 1). Right.

[Brief explanation of drawings]

FIGS. 1(a) and 1(b) show one embodiment of a soup electric actuator according to the present invention, and FIG.
a) is a sectional view, FIG. 1 (11) is a side view, FIG. 2 is a perspective view showing an example of a piezoelectric element mounted on the same piezoelectric actuator, and FIGS. 3G, t, Figure 4 is a schematic diagram showing one embodiment of a drive circuit for a piezoelectric actuator. This figure shows the booter map of the ROM 67. 10.20... Bracket 1~. 11.21... Holder, 12... Spring, 13, 23, 110, 21
0... Scrikou, 22, 30, 111, 113゜2
11.213...Spacer, 32,112°212.
...Piezoelectric water child, 40.41...Guide pin, 42,4
3,44,45...Nut, 50...Rod, 11
4.115,214,215...wedge, 116,
'216...set scrico, 320...hole, 3
21... Notch portion, 322... Disc, 323...
Laminated body, 324... Flat part, 325... Electrode, 60
...Drive circuit, 61...Polarization switch, 62...
Start switch, 63... Callan 1 one-way selection switch, 64... Oscillator, 65... OR circuit, 66...
Up/down counter (U/D counter), 67.
・Read-only memory (ROM), 68...D-
Flip-flop (D-FF), 69...driver.

Claims (2)

[Claims] (1) A telescoping mechanism consisting of a first piezoelectric element inserted into a rod to which a driven object is connected to one of its ends so that the electrostrictive action when a voltage is applied extends in the axial direction of the rod; a second piezoelectric element housed in a first holder in contact with the left end of the first piezoelectric element and penetrated into the rod so as to exert an electrostrictive action in the axial direction of the rod when a voltage is applied; By displacing the electrostrictive action by the second piezoelectric element in a direction perpendicular to the axial direction of the rod,
a first locking mechanism consisting of a wedge that fixes movement of the rod in the axial direction with respect to the holder; and a second locking mechanism that is housed in a second holder that is in contact with the right end of the first piezoelectric element and that prevents electrostriction when a voltage is applied. A third piezoelectric element penetrates into the rod so as to exert an action in the axial direction of the rod, and by displacing the electrostrictive action by the third piezoelectric element in a direction perpendicular to the axial direction of the rod. Said second
a second locking mechanism comprising a wedge that fixes movement of the rod in the axial direction with respect to the holder; and a wedge that prevents movement of one of the first and second holders in the axial direction of the rod. an elasticity imparting mechanism that provides a spring force that allows the other holder to follow the expansion and contraction action of the expansion and contraction mechanism and move in the axial direction of the rod when fixed; and the first, second, and third piezoelectric elements. A piezoelectric actuator comprising: a drive circuit that selectively applies voltage to; and a piezoelectric actuator. (2) The piezoelectric actuator according to claim (1), wherein each of the first, second, and third piezoelectric elements is formed by laminating thin disc-shaped piezoelectric materials in a cylindrical shape.