JPH0636673B2 - Drive - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a drive device that applies a driving force to a driven body, and more specifically, a drive device that applies a driving force to a driven body using a piezoelectric body having a piezoelectric effect. It relates to the device.

[Conventional technology]

Drive devices that apply a driving force to a driven body can be roughly classified into those that use electrical input and those that use fluid input. A typical example of the former drive device is an electric motor utilizing electromagnetic force, and a typical example of the latter drive device is an oil-pneumatic motor, an oil-pneumatic cylinder or the like.

On the other hand, in recent years, along with the development of the piezoelectric body, various drive devices using the piezoelectric body have been proposed. This piezoelectric body exhibits a phenomenon that distortion occurs when a voltage is applied, that is, a so-called inverse piezoelectric effect, and has been known for a long time. One method of a driving device using this piezoelectric material is as follows:
IBM Technical Disclosure Biltain Vol. 16, No. 6, published in January (IBM Te
chnical Disclosure Bulletine, Vol.16, No. 6) and the one described in Japanese Patent Laid-Open No. 53-82286, a flexible mechanism is provided for two piezoelectric bodies having a strained form in one direction. There is a mechanism in which the distortions in the orthogonal directions are combined by connecting and combining them in the orthogonal directions via.

[Problems to be Solved by the Invention]

In the arrangement of the piezoelectric bodies in this type of driving device, one of the piezoelectric bodies only makes a contact or non-contact operation between the driving end portion of the piezoelectric body and the driven body or changes the pressing force, and the driving force of the driven body is not changed. It has a structure in which only the other piezoelectric body does not participate and generates a driving force. Therefore, the efficiency is low. Furthermore, the tensile force is applied to the piezoelectric body on the driving force generating side during either forward rotation or reverse rotation, so the durability of the piezoelectric body is difficult. In particular, in recent years, a laminated piezoelectric material has been developed for the purpose of low voltage driving and large displacement of the piezoelectric material. However, applying tensile stress to this laminated piezoelectric material has a significant adverse effect on its life. .

The present invention has been made based on the above matters, and an object of the present invention is to provide a driving device using a piezoelectric body that can transmit a driving force with high efficiency and that has good durability. is there.

[Means for Solving the Problems]

In order to solve the above-mentioned problems, in the driving device of the present invention, the driving force is generated by synthesizing the vibrations of the first and second piezoelectric bodies arranged on the base so as to intersect with each other. A drive unit for driving the driven body by bringing the vibration synthesizing member into contact with the driven body. The first and second piezoelectric bodies are obliquely arranged so that their displacement directions are line-symmetric with respect to the normal line at the center of the contact portion between the vibration synthesizing member and the driven body. The piezoelectric body and the second piezoelectric body have respective portions facing each other, and the portion facing the first piezoelectric body is rigid in the displacement direction of the first piezoelectric body and is in the displacement direction of the second piezoelectric body. A flexible mechanism is formed, and the second piezoelectric body is formed in a portion facing the second piezoelectric body. Is the direction of displacement in the displacement direction of the at Tsuyoshi second piezoelectric flexible mechanism is a soft is formed.

[Action]

The first piezoelectric body and the second piezoelectric body are obliquely arranged so as to be line-symmetric with respect to the normal line of the driving direction at the contact portion between the vibration synthesizing member and the driven body. Further, the vibration synthesizing member does not reduce the displacement force of each piezoelectric body by the flexible mechanism. Therefore, when driving is performed with a phase difference between the vibration of the first piezoelectric body and the vibration of the second piezoelectric body, synthetic vibration having an elliptical locus is generated in the vibration synthesizing member. This combined vibration is transmitted to the driven body via the driving end portion, and the driven body is driven thereby. The displacement in the driving direction that contributes to the driving of the driven body is very large because it is obtained as a combination of the displacement amounts of both piezoelectric bodies in the configuration of the present invention, and the pressing force of the piezoelectric body against the driven body is also large. Since the pressing force of the piezoelectric body is combined, it becomes very large.

Further, in the above configuration, the first and second piezoelectric bodies are line-symmetric with respect to the normal line of the driving direction, so that the driving characteristics are not only constant when the driven body is driven in either forward or reverse directions. Not only that, since compressive stress is always applied to both piezoelectric bodies, damage to the piezoelectric bodies can be prevented.

Example of Invention

 Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an embodiment of the driving device of the present invention. In the figure, reference numerals 1 and 2 denote rectangular parallelepiped piezoelectric bodies, which are, for example, lead zirconate titanate [Pb (Zr, Ti).
O ₃ ] (abbreviated PZT) is used to form a laminated structure capable of large displacement at low voltage. Reference numeral 10 is a driving end portion of a vibration synthesizing member made of a wear resistant material such as ceramics, and 11 is a driven body.

Reference numeral 17 denotes a base having an inclined surface 17A of ± 45 ° with respect to a tangent plane at a contact point between the driven body 11 and the driving end portion 10. The inclined surface 17A of the base 17 has bottom surfaces of the piezoelectric bodies 1 and 2, respectively. Is stuck.

Therefore, each piezoelectric body has a displacement component of ± 45 ° with respect to the normal line at the contact point between the driven body 11 and the drive end portion 10, that is, the drive direction. That is, the directions of mechanical displacement of the piezoelectric bodies 1 and 2 are ± 4 with respect to the driving direction of the driven body 11, as indicated by arrows 5 and 6, respectively.
It crosses at an angle of 5 degrees. A vibration synthesizing member 18 having a flexible mechanism is provided between the piezoelectric bodies 1 and 2 and the drive end 10. This vibration synthesizing member 18 has a portion 1 facing the piezoelectric body 1.
8a and a portion 18b facing the piezoelectric body 2, and they are integrated to synthesize vibration. The part 18a of the member 18 rigidly transmits the force in the direction of the arrow 5,
A leaf spring structure is provided in which a slit is formed in the direction of arrow 5 so as to be flexible in the direction perpendicular to. Similarly, the vibration synthesizing member 18
18b has a leaf spring structure in which a slit is formed in the direction of arrow 6 so that the force is rigidly transmitted in the direction of arrow 6 and is flexible in the direction perpendicular to arrow 6. Therefore, the displacement of the piezoelectric body 1 displaces the drive end 10 in the direction of the arrow 5 without being disturbed by the piezoelectric body 2, and conversely the displacement of the piezoelectric body 2 causes the drive end 10 to move in the direction of arrow 6 without being disturbed by the piezoelectric body 1. Displace in the direction. The lower surface of the drive end portion 10 has surfaces orthogonal to the displacement arrows 5 and 6 of the piezoelectric bodies 1 and 2 in consideration of force transmission, and further, the drive end portion 10, the vibration synthesizing member 18, and the piezoelectric body 1, 1. 2 is integrally fixed. An elastic member 19 is provided between the vibration synthesizing member 18 and the base 17 so that the piezoelectric bodies 1 and 2 are always subjected to a compressive force. Base 1
7 is provided on the fixed wall 20. The driven body 11 is pressed against the drive end 10 from the fixed wall 21 via the elastic member 22 and the bearing means 23. Reference numeral 12 is an oscillator, 13 is an amplifier, 14 is a phase converter, 15 is an amplifier, and 16 is an operation controller. The controller 16 adjusts the frequency of the oscillator 12 and the phase of the phase converter 14.

The basic operation of the above-described embodiment of the device of the present invention is that when an AC voltage having an appropriate phase difference is applied to the piezoelectric bodies 1 and 2,
The respective displacements 5 and 6 are combined at the drive end 10.
The driving end portion 10 draws an elliptical locus so that the pressed driven body 11 is contact-driven in one direction.

Next, the operation of the above-described embodiment of the apparatus of the present invention will be described in more detail with reference to FIG.

FIG. 2 is an enlarged schematic representation of the operation of the embodiment of the apparatus of the present invention shown in FIG. Driven body 11
Piezoelectric body 1, which is arranged ± 45 ° to the contact surface of
If the maximum amplitude of each of the two is a, the range of motion of the drive end 10 falls within the square region B inclined by 45 ° on the side 2a. That is, when a maximum amplitude voltage having an appropriate phase difference is applied to the piezoelectric bodies 1 and 2, the drive locus A of the drive end portion 10 becomes an ellipse inside the square B, and its flatness depends on the phase difference of the voltage. The elliptical locus shown in FIG. 2 corresponds to a phase difference of approximately 120 ° between the two. In order to increase the driving efficiency, it is desirable to drive a flat elliptical locus so that the displacement in the direction perpendicular to the contact surface is as small as possible and the displacement in the contact surface direction is increased.
The displacement in the contact surface direction can be calculated by combining the displacements of the piezoelectric body with the maximum amplitude a. Can be close to. Therefore, when the piezoelectric body having the same performance is used, the piezoelectric body of the present invention can utilize the piezoelectric body more effectively than the conventional one. That is, the displacement in the contact surface direction is more than that of the conventional method. Drive speed because it will be close By driving force Closer, and in its output Improving near, greatly improving efficiency.

Further, according to the embodiment of the present invention, the pressing force of the driven body 11 to the driving end portion 10 is applied to the piezoelectric bodies 1 and 2 as a compressive force, and the spring member 19 also causes the piezoelectric bodies 1 and 1 to move. Since a compressive force acts on the piezoelectric body 2, a compressive stress is constantly applied to the piezoelectric bodies 1 and 2 in operation, and the durability of the piezoelectric body having a characteristic weak against tensile stress is greatly improved.

In the above-described embodiment of the present invention, the vibration synthesizing member 18 and the drive end portion 10 are separate members.
The drive end 10 may be formed by subjecting the surface 8 facing the driven surface 11 to abrasion resistance treatment such as ceramic coating.

Next, typical application examples of the driving device of the present invention will be described.

FIG. 3 and FIG. 4 show an application example of the drive device of the present invention, and this application example is an embodiment in which an actuator for rotating the driven body 11 is configured. 3 and 4, the same reference numerals as those in FIG. 2 represent the same parts. In FIG. 3, the drive end portion 10 is a countersunk screw 24 and is used as a vibration synthesizing member 18.
It is fixed to. Further, as a member corresponding to the elastic member 19, a part of the base 17 is made to have a spring property, and the vibration synthesizing member 18 and the base 17 are coupled with each other by the bolt 25, so that the piezoelectric body 1,
2 is given compressive force. In the rotary actuator of this embodiment, as shown in FIG. 4, the disk-shaped fixed wall 20 is provided with three units of the driving device of the present invention, and the opposed annular driven body 11 is supported by three-point contact. It has a structure.
In FIG. 3, only the front drive unit is shown, and the rear drive unit is omitted. The driven body 11 is the elastic member 2
2 is fixed to the rotor 26 via the stop ring 2
It is pressed against the drive end 10 by 7. The rotor 26 is supported by a rotary bearing provided between the fixed wall 20 and the casing 28.

The operation of this rotary actuator will be described below. As already described in detail, when an AC voltage having an appropriate phase difference is applied to the piezoelectric bodies 1 and 2, the driving end portion 10 makes an elliptic motion. Therefore, when the driving ends 10 of the three driving devices installed in the present rotary actuator are synchronously moved in an elliptical motion, the driven body 11 and the rotor 26 that are contact-supported at three points are continuously moved in one direction. It can be rotated. If the phase difference between the voltages applied to the piezoelectric bodies 1 and 2 is reversed, the rotor 26 naturally rotates in the reverse direction.

FIG. 5 shows another application example of the driving device of the present invention.
This application example is one example in which an actuator for linearly moving the driven body 11 is configured. In FIG. 5, two driving devices of the present invention are provided on opposing fixed walls 20a, 20b via elastic members 22a, 22b, and each driving end 10 presses and supports the driven body 11. There is. The operation of the linear movement actuator is to drive the driven body 11 continuously in one direction by driving the respective drive devices in synchronization in the same manner as the operation of the rotary actuator.

〔The invention's effect〕

As described in detail above, according to the present invention, it is possible to provide a driving device that can efficiently transmit a driving force to a driven body and further improve the durability of the piezoelectric body.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of an embodiment of a driving device of the present invention,
FIG. 2 is an operation explanatory view of an embodiment of the driving device of the present invention, FIG. 3 is a front view showing a rotary actuator to which the driving device of the present invention is applied in a partial section, and FIG. 4 is FIG. IV-IV
FIG. 5 is a diagram showing a linear movement type actuator to which the driving device of the present invention is applied. 1,2 ... Piezoelectric body, 5,6 ... Piezoelectric body displacement direction, 7,
8 ... Flexible mechanism, 10 ... Driving end, 11 ... Driven body,
12 ... Oscillator, 13, 15 ... Amplifier, 14 ... Phase converter, 16 ... Operation controller, 17 ... Base,
18 ... Vibration synthesizing member, 19 ... Elastic member.

Claims (2)

[Claims] 1. A driving force by synthesizing vibrations of a first piezoelectric body and a second piezoelectric body and a vibration of the first piezoelectric body and the second piezoelectric body, which are arranged on a base so as to intersect with each other. And a power supply means for exciting the first piezoelectric body and the second piezoelectric body to vibrate, and the vibration synthesizing member and the driven body are brought into contact with each other. In the drive device for driving the driven body by force, the displacement direction of the first piezoelectric body and the second piezoelectric body is a normal line at a center of a contact portion between the vibration synthesizing member and the driven body. The vibration synthesizing members are arranged obliquely so as to be line-symmetrical with respect to each other, and the vibration synthesizing member has portions facing the first piezoelectric body and the second piezoelectric body, respectively. The opposing portions are rigid in the displacement direction of the first piezoelectric body and in the displacement direction of the second piezoelectric body. A flexible mechanism is formed that is flexible and is rigid in the displacement direction of the second piezoelectric body and is flexible in the displacement direction of the first piezoelectric body in a portion facing the second piezoelectric body. A drive device characterized by being formed. 2. A driving force by synthesizing vibrations of a first piezoelectric body and a second piezoelectric body and a vibration of the first piezoelectric body and the second piezoelectric body, which are arranged on a base so as to be orthogonal to each other. And a power supply means for exciting the first piezoelectric body and the second piezoelectric body to vibrate, and the vibration synthesizing member and the driven body are brought into contact with each other. In a drive device for driving the driven body by force, the displacement directions of the first piezoelectric body and the second piezoelectric body are normal to a center of a contact portion between the vibration synthesizing member and the driven body. And the vibration synthesizing member has portions facing the first piezoelectric body and the second piezoelectric body, respectively. The opposing portions are rigid in the displacement direction of each piezoelectric body and are orthogonal to the displacement direction. A flexible mechanism is formed on the base plate, and an elastic member that applies a compressive force to the first and second piezoelectric bodies is provided between the vibration synthesizing member and the base. Drive device.