JPS6260480A - Ultrasonic motor with abrasion preventive mechanism - Google Patents

Abstract

PURPOSE:To stabilize operation by mounting a stopper mechanism, through which an excess over a predetermined level of a sliding surface in a rotor and vibrations to the stator side are obstructed, when the rotor is subjected to the longitudinal vibration component of the elliptical vibrations of a stator and longitudinally vibrate. CONSTITUTION:A terminal board 5 is held between piezoelectric vibrators 2, 3, an end dust board 4 is superposed on the outside, a cap bolt 10 set to a washer 6 is penetrated to these vibrators and boards, and made to pass through an aluminum drum section 7, and the nose of the bolt 10 is penetrated to a bolthole for a torsional connector 8 in aluminum and clamped, thus unifying these vibrators, boards, drum section and connector, then constituting a stator. The stator is fitted to a case-shaped frame body 1, and the washer 6 is pressed in and fixed to the frame body 1. The outer circumference of a rotor 9 is supported by a ring-shaped shelf section 1' for the frame body 1. The frame body 1 prevents a contact with the stator on antiphase of the rotor 9.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to an ultrasonic motor, and includes 2! More specifically, the present invention relates to an improvement in a sliding mechanism between a stator and a rotor.

[Conventional technology and its problems]

In conventional devices of this kind, -C is 1, for example, as disclosed in Japanese Patent Application No. 59-172429 or Japanese Unexamined Patent Publication No. 56-138 filed by the present inventor.
As shown in No. 469, the rotational torque generated in the rotor is utilized by pressing the rotor onto the back surface of the stator that vibrates elliptically. Since the output torque of the motor depends on the pressure force, in order to increase the output torque, the pressure force between the rotor and stator must be increased. On the other hand, the elliptical vibration of the stator with the rotor strongly compressed suppresses the in-plane component perpendicular to the stator, resulting in a distorted ellipse, and the force the rotor receives is not only the component that contributes to rotation, but also the return component that opposes rotation. This has the drawback of causing a discrepancy in the relative speed between the rotor and stator surfaces, resulting in wear.

The object of the present invention is to solve the drawback of the above-mentioned conventional products, such as wear on the sliding surface between the rotor and stator, and thereby provide an ultrasonic motor with excellent durability.

[Means to solve the problem]

The reason why the sliding surface of an ultrasonic motor wears out is that there is a difference between the vibration speed of the stator and the linear velocity of the sliding surface as the rotor rotates. If there is no deviation in the relative speed, the torque transmission by rollers is the same as the v1 structure, so in principle no wear will occur. The vibration of the free end surface of the stator when the rollers are not pressed is an elliptical motion within a plane that includes the normal to the surface (a plane perpendicular to the end surface), and the horizontal component of the elliptical motion changes over time. Since it is a reciprocating motion that fluctuates in a sinusoidal manner, it never becomes a constant value. However, when the rotor is pressed, the vertical component of the elliptical motion is suppressed in response to the pressing force, and the head of the ellipse deforms as if it were flattened horizontally. In this deformed part, the motion is constant and balances the inertia of the rotor, and no deviation occurs.

If the pressing force becomes even larger, the position of the rotor's horizontal plane changes over time, making the deformation of the ellipse more complicated, and the rotor and stator come into contact even when the elliptical motion is in opposite phase, causing H wear. Become. This can be prevented by supporting the rotor so that its sliding surface is always maintained at a constant horizontal position. In other words, when the rotor receives the elliptical motion of the stator and applies rotor torque in the horizontal direction, vibration in the vertical direction also acts at the same time.
The greater the pressure force, the greater the effect of the vertical component. As a result, even if the rotor is in the opposite phase of the ellipse, which should be separated from the stator, the rotor and stator are in strong contact, resulting in wear.To prevent this, it is necessary to It is sufficient to adopt a structure in which the rotor does not come into contact with the stator.

The present invention has been made based on the above technical idea, and includes a stator that vibrates in an elliptical manner and a rotor that is crimped onto the end face of the stator. The sonic motor is characterized by being provided with a stopper mechanism that prevents the sliding surface of the rotor from vertically vibrating toward the stator beyond a certain level due to the vertical component of the elliptical vibration of the stator. It is.

〔Example〕

An embodiment of an ultrasonic motor having a wear prevention mechanism according to the present invention will be described below with reference to the drawings.

Embodiment 1 FIG. 1 is a partial sectional view showing a first embodiment of the present invention, and its structure is compared with a conventional technology, for example, an ultrasonic motor shown in an embodiment of Japanese Patent Application No. 59-172429. The basic difference is that a frame 1 is provided to prevent the rotor from sinking, the cross section of which is shown with diagonal lines in FIG. Other aspects are the same as the conventional piezoelectric motor using a cantilever type ultrasonic elliptical vibrator that the present inventor has proposed in the past. That is, a terminal plate 5 with a lead wire is sandwiched between two piezoelectric vibrators 2 and 3 made of PZT, for example, with their positive electrode surfaces facing each other, and another end dust plate 4 is placed on the outside. , pass these through the cap bottle 10L set on the washer 6, then pass them through the aluminum body 7, and then pass the tip of the bolt through the bolt hole of the aluminum torsion connector 8 and tighten them to integrate them, It was configured as a stator. The completed stator was fitted into a case-like frame 1 made of a synthetic resin with excellent slipperiness and rigidity, such as acetal resin or fluorocarbon resin, and a washer 6 was press-fitted into the frame 1. The frame has a ring-shaped shelf 1', and the outer periphery of the rotor is supported by this shelf 1', so the upper surface of the shelf 1' and the end surface of the stator are almost in the same plane. The stator is press-fitted into the frame 1, the rotor 9 is set, and a predetermined high frequency voltage is input between the lead wires 4 and 5 to rotate the rotor 9, and the magnitude of the output torque is determined.

Considering the smoothness of rotation, we finely adjusted the relative level difference between the upper surface of the shelf 1' and the end surface of the stator.

Rotor 91′! Bolt l passed through coil spring 12
1 was crimped by tightening it into the screw hole 14 on the end face of the stator. Note that a ball bearing 13 is interposed between the coil spring 12 and the rotor 9 so that the rotor 9 rotates smoothly. Tighten the bolt 11 sufficiently and connect the lead wires 4 and 5 with 34.70Kilz, I OOV.
When a sinusoidal voltage of 1 was applied, the rotor 9 rotated quietly at a rotation speed of about 150 rpm. Output torque is approximately 6Kg c
It was m.

Since the rotor 9 vibrates up and down in response to the up and down components of the ultrasonic vibrations of the stator, if the level adjustment of the shelf section 1' is incorrect, it will come into contact with the stator in the opposite phase, causing squeaks and wear. Even in the case of a conventional frameless motor, it is possible to achieve a state without squeaks and wear by finely adjusting the crimp force and frequency to VUa, but if left in that state for 30 minutes to several hours, the crimp conditions will deviate. A squeaking sound begins to appear, and soon after the squeak begins, the rotor 9 burns into the stator.
The rotation has stopped.

The frame 1 of this embodiment prevents the rotor 9 from contacting the stator when the phase is reversed, so once! After 1 m of oil, no squeaks or burn-in occurred even after leaving it for about 1 month.

Note that the shelf 1'- formed in the frame 1 is for supporting the lower surface of the rotor 9, and its shape is not limited to a ring shape. 41 portions may be equally distributed in the inner circumferential direction of the frame body 1.

Embodiment 2 FIG. 2 shows another embodiment of the ultrasonic motor having a 12 mm resistance mechanism according to the present invention.

In the ultrasonic motor of this embodiment, the rotor receives the vertical vibration of the stator, the vertical vibration is excited by the reaction of the crimping force, and the rotor comes into contact with the end face of the stator at the opposite phase of the elliptical vibration of the stator, creating a gap between the rotor and the stator. Squeak due to surface misalignment based on the difference in relative speed of #! To prevent wear, a thrust bearing is installed between the end of the rotor and stator, and even if the rotor vibrates strongly toward the stator when the stator is out of phase, the thrust bearing prevents the vibration. However, by preventing the rotor from approaching the stator any further, the rotor is prevented from being pressed against the stator surface.

That is, in this embodiment, as shown in FIG.

Put the thrust bearing 23 in the center of the rotor 22,
A bolt 26 with a coil spring 25 attached to its outer periphery
is tightened to the end face 21' of the torsion coupler 21 through the swing prevention bearing 24 and the thrust bearing 27, and the sliding surface 22'' of the rotor 22 is crimped to the end face 21' of the torsion coupler 21.As described above, Ultrasonic motor configured.

Since excessive crimping is prevented by the thrust bearing 23, it is possible to prevent the rotor from coming into contact with the stator at the opposite phase of the stator's elliptical vibration, thereby preventing the rotor from making a squeaky sound and causing wear.

In addition, as a result of six experiments in which it is possible to use the stopper mechanisms described in each of the above embodiments in combination, rather than applying them individually, the combination of both mechanisms was found to be the most effective in improving wear resistance. It worked. .

〔Effect of the invention〕

As explained above, in the present invention, in an ultrasonic motor whose driving force is rotational torque generated in the rotor by crimping the rotor to the end face of the stator that vibrates in an elliptical manner, the rotor generates a vertical vibration component of the elliptical vibration of the stator. Therefore, we adopted a stopper mechanism that prevents the sliding surface of the rotor from exceeding a certain level and vibrating toward the stator when vertical vibration occurs, so that the rotor will not move during the opposite phase when the stator contracts. This prevents undesirable situations such as the stator coming into contact with the stator and causing squeaks and wear, and the rotor seizing up and preventing rotation, thereby stabilizing rotation and increasing output torque. , and extended the life of the motor.

[Brief explanation of drawings]

FIG. 1 is a partial sectional view showing a first embodiment of an ultrasonic motor with a wear prevention mechanism according to the present invention, and FIG. 2 is a partial sectional view showing the structure of a rotor in the second embodiment.

Claims (3)

[Claims] (1) In an ultrasonic motor that is equipped with a stator that vibrates elliptically and a rotor that is crimped onto the end face of the stator, and uses the rotational torque generated in the rotor as a driving force, the vertical component of the elliptical vibration of the stator An ultrasonic motor having a wear prevention mechanism, characterized in that a stopper mechanism is provided to prevent the sliding surface of the rotor from vertically vibrating toward the stator beyond a certain level. (2) As a stopper mechanism for an ultrasonic motor having a wear prevention mechanism according to claim 1, one end is fixed to a stator, and the other end is formed with a shelf part that supports the sliding surface of the rotor. A filter ultrasonic motor having a wear prevention mechanism characterized by using a frame made of resin material. (3) As a stopper mechanism for an ultrasonic motor having a wear prevention mechanism as set forth in claim 1, a thrust bearing is interposed between the rotor and a bolt that presses the stator and rotor. Ultrasonic motor with anti-wear mechanism.