JPH04279A - Ultrasonic motor - Google Patents

Abstract

PURPOSE:To reduce abrasion as well as transmission loss and improve driving efficiency by transmitting a torque to a moving piece through a gear. CONSTITUTION:When an AC voltage is impressed on a piezo electric body 1, the piezo-electric body 1 is oscillated while the oscillation is amplified by the rod 2 made of aluminum and the amplitude of the tip end of a Langevin oscillator is increased. A micro-gear 3, attached to the tip end of the Langevin oscillator, is rotated into only a direction shown by an arrow sign in a diagram. When the oscillator is elongated, the micro-gear 3 is displaced, however, the micro-gear 3 is meshed with a gear 5 and is not rotated except the arrow sign direction whereby the amount of displacement of the micro-gear 3 becomes the amount of displacement of the moving piece 4 as it is. On the other hand, the micro-gear 3 is displaced when the oscillator is contracted, however, the gear 3 is rotated into the arrow sign direction while meshing with the gear 5 whereby no force is applied on the moving piece 4. The moving piece 4 is moved into a direction, shown by a broken line, by the elongating and contracting motion of the oscillator in such a manner.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an ultrasonic motor comprising a Langevin element made of piezoelectric ceramics and a mover.

(Prior Art) Electric motors commonly used today are driven using electromagnetic action, and their performance depends on the characteristics of the magnetic and conductive materials that make up the motor. . Therefore, although it is possible to improve performance by improving these materials, the reality is that dramatic improvements can no longer be expected, or even if improvements are made, the extent is very small. Recently, ultrasonic motors have been attracting attention as a new actuator. The ultrasonic motor is of a type in which the motor is driven by ultrasonic energy emitted from a vibrator.

As such an ultrasonic motor, for example, research paper "
"Prototype production of ultrasonic drive motor" (Applied Physics 51.713<
1982>: Satoshi Sashida) describes the following ultrasonic motor.

A vibrating piece is fixed to the tip of a piezoelectric vibrator that generates bending vibration in a direction perpendicular to the axial direction of the motor. A rotor that rotates in one direction and whose rotation center is located at the center is disposed, and the tips of the vibrating pieces are in contact with the periphery of the rotor. By applying voltage from a power source to the piezoelectric vibrator, the vibrating piece vibrates ultrasonically, and its tip periodically contacts the rotor, causing the rotor to rotate due to the frictional force between the vibrating piece and the rotor. .

Compared to electric motors, the ultrasonic motor configured in this way is: ■) Smaller and lighter, 2) Simpler in structure, and 3)
It has advantages such as high efficiency and 4) excellent controllability.

(Problem to be solved by the invention) However, in such an ultrasonic motor, since the means of transmitting the moving torque of the vibrating stator to the rotor is by frictional force, the sliding surfaces are prone to wear and fatigue, and the durability is poor. There were problems such as low performance and reduced efficiency.

(Means for Solving Problem 1) The present invention transmits torque generated in an ultrasonic vibrating elastic transducer to a moving element not by contact friction but only in one direction attached to the tip of the transducer. A rotating micro gear and a gear that meshes with the micro gear are formed in a moving element, and torque is transmitted by meshing both gears,
We came up with an ultrasonic motor that can solve the problems mentioned above.

The present invention provides an ultrasonic motor consisting of a Langevin element made of piezoelectric ceramics and a mover, wherein the Langevin element is fixed and has a micro-gear that rotates only in one direction at its tip, and the mover An ultrasonic motor is provided, characterized in that the ultrasonic motor is provided with a gear provided in the longitudinal direction or around the micro-gear so as to mesh with the micro-gear.

(Function) The ultrasonic motor of the present invention is an ultrasonic motor consisting of a transducer made of a Langevin element and a moving element. At the tip of the transducer, a micro gear that rotates in only one direction is attached to the moving element. It is necessary that a gear that meshes with the micro gear is formed.

The Langevin element mainly refers to a device in which a piezoelectric body and an elastic body such as metal or ceramics are bonded together, and the elastic body vibrates ultrasonically due to the amplitude of the piezoelectric body. With this structure, the piezoelectric element transmits the torque of the Langevin vibrator that vibrates ultrasonically to the movable element via the gear, so wear due to friction between the movable element and the vibrator is extremely reduced, and the above-mentioned problem can be achieved. This is because the problem is solved in one go.

The mover may be of either a so-called linear type or a rotary type.

If the mover is a linear type, a gear that meshes with the micro gear may be formed in the longitudinal direction of the mover, or if it is a rotary type, on the outside or inside of the circumference of the mover (rotor). is necessary.

Further, since the micro gear formed at the tip of the vibrator of the present invention rotates only in one direction, the movement or rotation direction of the mover is limited to one direction.
The piezoelectric material used in the present invention, which can control the direction of movement or rotation by combining two types of oscillators and switching each oscillator as necessary, is a crystal oscillator or PZT (titanate, lead zirconate). ) can be used, and the excitation frequency of the applied voltage can be arbitrary.

Next, an example will be described and the driving principle will be explained.

Example 1 This embodiment relates to a linear type ultrasonic motor.

FIG. 1 is a side view of the present invention. An aluminum rod 2 was adhered to the side surface of a polarized piezoelectric body 1 made of lead zirconate titanate to form a Langevin oscillator.

Next, a micro gear 3 that rotates in only one direction was attached to the tip of this element, and a mover 4 on which a gear 5 that meshed with the micro gear 3 was formed was held, thereby obtaining an ultrasonic motor.

The driving principle of this ultrasonic motor is explained below.When an AC voltage is applied to a piezoelectric body, the piezoelectric body vibrates, and this vibration
It is amplified by the aluminum rod 2, and the tip of the Langevin oscillator vibrates greatly. The micro gear 3 attached to the tip of this Langevin oscillator rotates only in the direction of the arrow (solid line) in Fig. 1.When the oscillator extends, the micro gear 3 is displaced;
Since it meshes with the gear 5 and rotates only in the direction of the arrow in FIG. 1, the amount of displacement of the micro gear 3 directly becomes the amount of displacement of the mover 4. Also, when the oscillator contracts,
Although the micro gear 3 is displaced, it rotates in the direction of the arrow in FIG. 1 while meshing with the gear 5, so no force is applied to the mover 4. Therefore, the mover 4 is either moving due to inertia or is stationary.

Such expansion and contraction of the vibrator causes the mover 4 to move in the direction of the broken line in FIG.

Example 2 The ultrasonic motor of this embodiment is shown in FIG.

FIG. 2 shows an ultrasonic motor obtained by forming linear gears on both sides of the mover 4 and installing a vibrator, which is a combination of a Langevin vibrator and a micro gear 3 similar to that in Example 1, on each side. It is.

Electromagnets Ml and M2 are attached to the second ultrasonic motor, and when the electromagnets are activated, the micro gear 3
The vibrator is separated from the gear 5, and the vibrator that acts on the mover 4 can be selected by selecting the electromagnet to be activated. Therefore, when the transducer LL is selected, the movable element 4 is moved in the ten direction, and when the transducer L2 is selected, the movable element 4 is
Since it moves in the - direction, the direction of movement can be controlled.

Example 3 The ultrasonic motor of this embodiment is shown in FIG.

FIG. 3 shows an example in which a rotary type mover 4 (rotor) is used in place of the linear type mover 4 shown in FIG.

As in the first embodiment, when the Langevin oscillator performs an expansion and contraction movement, the rotary mover rotates in the direction of the arrow (broken line) in FIG. 3.

Example 4 The ultrasonic motor of this embodiment is shown in FIG.

FIG. 4 shows an example in which the gear 5 is formed inside the circumference of the rotary mover 4.

As in the first embodiment, when the Langevin oscillator undergoes expansion and contraction vibration, the rotary mover 4 rotates in the direction shown by the arrow (broken line) in FIG. 4.

(Effects of the Invention) In the ultrasonic motor of the present invention, torque is transmitted to the movable element through gears, so there is less wear and less transmission loss than in the conventional case where torque is transmitted by frictional force. Therefore, driving efficiency is improved.

[Brief explanation of drawings]

Figure 1 shows a linear ultrasonic motor. Figure 2 shows an ultrasonic motor that can control the direction of movement. Figure 4 shows a rotary ultrasonic motor. piezoelectric body Elastic body (metal rod) micro gear Mover (rotor) gear Mover support gear Ll, L2 Ml, M2 Oscillator (Langevin oscillator and Combined with micro gear of) electromagnet Patent application 1 IBIDEN Co., Ltd. Representative: Shin Taga NF2 diagram Figure 3 Figure 2 4th A

Claims (1)

[Claims] An ultrasonic motor consisting of a Langevin element made of piezoelectric ceramics and a mover, the Langevin element being fixed and equipped with a micro gear that rotates in only one direction at the tip, and a micro gear that rotates in one direction only in the longitudinal direction or around the mover. An ultrasonic motor comprising a gear provided to mesh with the micro gear.