JPH03222681A - Ultrasonic motor - Google Patents

Abstract

PURPOSE:To enable highly accurate positioning of a moving member with respect to a fixed member by employing a hollow frame, having axis in parallel with the moving direction of the moving member, as the fixed member or the moving member. CONSTITUTION:A moving member, i.e., a moving frame 2, comprising a hollow cylindrical body is arranged movably in the axial direction at the inside of a fixed member, i.e., a fixed frame 1, comprising a hollow cylindrical body through a predetermined gap, and a slide board 3 extending in the axial direction of the moving frame 2 is secured to the moving frame 2 at a part above the gap between the fixed frame 1 and the moving frame 2. When an oscillator 12 disposed at a position facing with the support 13b of the moving frame 2 is pushed in the axial direction O through the slide board 3, centripetal function is produced by linear grooves 1a-1c, 2a-2c and the supports 13a-13c and thereby the moving frame 2 is aligned accurately and precisely to the fixed frame 1.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an ultrasonic motor, and more particularly to a hollow linear type ultrasonic motor in which a hollow moving member is driven in a straight line.

[Prior Art] In recent years, as is well known, ultrasonic motors have attracted attention as actuators that can drive focusing operations of camera lenses and the like in a small space. The reason for this is that ultrasonic motors can obtain large torque at lower speeds than conventional electromagnetic motors, so they can drive the lens holding frame directly, so there is no need for reduction gears, and they are compact, silent, and highly accurate. This is because high-response lens drive can be achieved.

By the way, when using an ultrasonic motor as an actuator for driving a camera lens, the actuator can be installed within the hollow cylindrical frame that houses the lens holding frame without taking up space, but its shape and arrangement must be consistent. It requires some ingenuity.

JP-A-1-2226, which realized this,
There is an annular ultrasonic motor using a traveling wave, which is disclosed in Japanese Patent No. 72. This generates a traveling wave in the circumferential direction of a ring-shaped vibrator, presses the end face of a cylindrical body serving as a rotor to the end face where the traveling wave is generated, and rotates the cylindrical body. In order to convert the rotation of the lens into a linear movement of the lens, a conversion mechanism such as a cam or a helicoid screw is provided on the cylindrical body, and this mechanism moves the lens forward and backward in the optical axis direction.

Furthermore, as disclosed in Japanese Patent Publication No. 60-7245, a lens has been proposed in which an inchworm type actuator is provided in the lens to drive the lens in a straight line. This is designed to drive the lens holding frame in a straight line by sequentially operating two actuators for clamping and one actuator for driving.

Furthermore, as seen in Japanese Unexamined Patent Publication No. 62-99714, a traveling-wave rail-shaped linear motor is arranged around the outer periphery of the lens holding frame, and the lens holding frame is moved by the progressive vibration waves generated in the linear motor. Some are configured to be driven.

[Problems to be Solved by the Invention] However, in order to drive a lens with the annular ultrasonic motor using a traveling wave disclosed in the above-mentioned Japanese Patent Laid-Open No. 1-222672, the above-mentioned method is necessary. A conversion mechanism such as a helicoid screw or a cam is required to convert the rotational motion generated by the motor into linear motion, and if the motor is hollow, it will be large and complicated. Furthermore, since a helicoid screw or cam is used, there is also a drawback that it is difficult to accurately determine the positional accuracy of the lens holding frame due to mechanical play.

Furthermore, with the inchworm type actuator shown in the above-mentioned Japanese Patent Publication No. 60-7245, which uses the inchworm type actuator for lens drive, due to its operating mechanism, it is only possible to realize drive up to a step frequency of about several KHz. The disadvantage is that the operation speed is slow, and the clamping actuator must hold the lens frame fixedly on the fixed frame when clamping, and be completely separated from the fixed frame when not clamped, but this clamping actuator is a multilayer A piezoelectric body is used, and its operating stroke is several micrometers to several tens of micrometers, and the clamping operation may become unstable due to abrasion of the clamping surface, causing the lens drive to stop. Furthermore, in order to hold the lens in a certain position, it is necessary to keep the actuator energized to keep it in a clamped state, which also causes the problem that energy is consumed even when the lens is not in operation.

On the other hand, the traveling wave type linear ultrasonic motor disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 62-99714 requires a closed-loop shaped vibrator to be disposed around the outer periphery of the lens to generate a traveling wave. Using a damping material increases the size of the lens frame, and since traveling waves are used, it is difficult to fix the transducer without damaging the vibration. The position of the lens relative to the member in the direction perpendicular to the lens optical axis cannot be precisely determined.

Therefore, the present applicant has previously proposed an ultra-compact linear ultrasonic motor designed to eliminate these drawbacks in Japanese Patent Application No. 1-1999.
It was proposed in No. 5767. This ultrasonic motor is equipped with a vertical vibrator that vibrates in a direction perpendicular to the plate at the node of the bending standing wave of the plate, and by combining the bending standing wave vibration and the longitudinal vibration, an elliptical shape is formed on the end face of the vertical vibrator. The vibration is generated to drive a movable body that is crimped onto the end face of a vertical vibrator.

An object of the present invention is to further configure the linear ultrasonic motor proposed in the above-mentioned Japanese Patent Application No. 1-195767 so as to be able to drive a hollow moving member in a straight line, and at the same time to provide a space-saving and simple structure. Furthermore, it is an object of the present invention to provide a highly efficient hollow linear type ultrasonic motor that can position and guide a moving member with respect to a fixed member with high precision.

[Means and effects for solving the problem] A hollow linear type ultrasonic motor according to the present invention includes a bending vibrator that generates bending vibration by applying a high frequency voltage, and a longitudinal vibration in the amplitude direction of the bending vibration. A vibrator supported by a fixed member and a longitudinal vibrator that generates a a movable member that moves with respect to the fixed member; and a guide member that is provided between the fixed member and the movable member and guides movement of the movable member with respect to the fixed member, and at least one of the fixed member and the movable member. One of the movable members is a hollow frame having a central axis parallel to the moving direction of the movable member, and the movable member is formed into a hollow frame having a flat surface at least partially parallel to the moving direction, It is characterized in that the flat surface is pressed against the tip of the vertical vibrator.

[Example] The present invention will be explained below with reference to illustrated embodiments.

FIGS. 1A and 1B are cross-sectional views of an ultrasonic motor showing a first embodiment of the present invention. Inside the fixed frame 1, which is a fixed member made of a hollow cylindrical body, a movable frame 2, which is a movable member also made of a hollow cylindrical body, is arranged so that it can move in the central axis direction with a certain gap. will be established. Then, the upper part of the gap between fixed frame 1 and movable frame 2 (in Fig. 1)
A slide plate 3 extending in the central axis direction of the movable frame 2 is fixed on a part of the movable frame 2.
A rectangular notch hole 1d (see FIG. 2), which is long in the front-rear direction of the central axis, is bored in the middle portion of the fixed frame 1 facing the center axis. This notch hole 1d is a hole for arranging a vibrator, which will be described later.

On the other hand, a support guide mechanism for the moving frame 2 is provided in a gap on the opposite side to the gap in which the slide plate 3 is arranged. In this embodiment, this support and guide mechanism is composed of three guide grooves and a support member, which is a guide member, consisting of a plurality of bearing balls arranged in each of the same bays. That is, at opposing positions of the slide plate 3 sandwiching the central axis 0, a straight groove 2b consisting of a partially arcuate recess is bored in the outer circumferential surface of the movable frame 2 in the direction of the movable frame's central axis. A straight line consisting of a partial arc-shaped recess in the fixed frame center axis direction is located halfway in the axial direction opposite to the straight groove 2b on the inner circumferential surface of the fixed frame. 1It1
Further, straight grooves 1g, 2a, slc, 2c, which are also partially arcuate concave portions, are provided at equal distances in the circumferential direction on both sides of the double-sided line grooves lb, 2b. Perforations are provided in the outer circumferential surface and the inner circumferential surface of the movable frame 2, respectively, in the direction of the central axis 0. And each of the above-mentioned straight grooves 1 a, 2 as 1 b.

Inside 2b, lc, and 2c is a support 13a made up of a plurality of bearing balls that constitute a guide member.

13b and 13c are provided, respectively.

In this support mechanism, when a vibrator 12 (described later) disposed at a position facing the support body 13b of the movable frame 2 is pressed toward the central axis 0 direction via the slide plate 3,
Said straight grooves 1a to 1c and 2a to 2C and support body 13a
~13c acts as a centripetal action, and the movable frame 2 becomes the fixed frame 1.
It is placed accurately and precisely so that the central axis coincides with the Furthermore, as shown in FIG. 1(B), the supports 13a to 13c have a plurality of bearing balls arranged in the direction of the central axis of the fixed frame 1, so that the movable frame 2 is supported without any wobbling of the central axis. . Further, the moving frame 2 is supported by a support body 13a.
~13c only, so moving frame 2. If only the linear grooves 1a-IC and 2a-2C of the fixed frame 1 are machined with high precision, the movable frame 2 can be positioned with respect to the fixed frame 1 with high precision.

As shown in FIG. 2, the notch hole 1d is bored in the middle of the upper part of the fixed frame 1, facing the slide plate 3.

That is, the middle of the upper circumferential surface of the fixed frame 1 is cut off in a direction perpendicular to the central axis 0 to form a plane part, and a notch hole consisting of an axially long rectangular through hole is formed in the center of the plane part. 1d is drilled.

Therefore, on both sides of the notch hole 1d in the axial direction, there are flat portions 1d.
is formed, and this plane portion 1do serves as a mounting portion for the holder 8 that supports the vibrator 12.

The vibrator 12 includes a bending vibrator 11 and a longitudinal vibrator 4. The bending vibrator 11 has the cutout hole 1
The piezoelectric body 6 consists of a relatively thick rectangular elastic body 5 and a thin rectangular piezoelectric body 6 having a length shorter than the elastic body 5 and having a size that is arranged with a margin within d. is fixed to the upper surface of the elastic body 5 with a boxy adhesive.

A driving high-frequency voltage is applied to the piezoelectric body 6 of the bending vibrator 11 in the thickness direction thereof, and in the case of this embodiment, a first-order bending resonance is generated. It has become. At the two nodes of this bending vibration, a vertical vibrator 4 is formed on the lower surface of the unfixed elastic body of the piezoelectric body 6 in the shape of a rectangular column made of a laminated piezoelectric body, and vibrates longitudinally in the thickness direction of the laminated plate.
is fixed so as to vibrate longitudinally in the thickness direction of the bending vibrator 11.

In addition, the bending vibrator 11 has four cylindrical support pins 7 fixed to the elastic body 5, each extending outward in the board width direction of the bending vibrator 11 at six positions of the nodes. A holder mounting groove 7a is provided in the middle of the pin 7 in the circumferential direction.

The vibrator 12 configured in this manner is housed and held from below in a holder 8 that has a channel-shaped cross section and is formed in a shape that covers the vibrator 12 from above. That is, the holder 8 is formed by bending a thin elastic plate, and an oval hole-shaped receiving part 8a with an open bottom is provided on the hanging wall of the holder 8 at a position corresponding to the support pin 7. The lower open portion of the receiving portion 8a is formed with a notch having a width slightly smaller than the diameter of the holder mounting groove portion 7a.

Further, in the middle of the rain hanging wall of this holder 8, a mounting fixing part 8b is provided which is bent outward and extends horizontally.
Apertures 8c are formed through which the holes 8c pass through, respectively.

The vibrator 12 is stored in the holder 8 so that it can vibrate freely by tightly fitting the holder mounting groove 7a of the support bin 7 into the receiving part 8a. A fixing screw 10 is passed through the opening 8C of the fixing frame 1 through the disc spring 9, and the fixing screw 10 is inserted into the flat part 1d of the fixing frame 1.

The vibrator 12 is disposed within the cutout hole 1d of the fixed frame l by screwing it into the screw hole 1e screwed into the fixed frame l. The lower end surface of the vertical vibrator 4 of the arranged vibrator 12 is pressed against the upper plane of the slide plate 3 fixed to the movable frame 2.

The operating principle of the ultrasonic motor of this embodiment configured as described above is the same as that of Japanese Patent Application No. 1195767 previously proposed by the applicant, in which the phase difference between the bending vibration and the longitudinal vibration is set to 90''. This generates elliptical vibration on the end face of the vertical vibrator 4 that moves the movable frame 2 forward and backward in the direction of its central axis.2
Since the two vertical vibrators 4 are configured to vibrate with a phase difference of 180', only the unidirectional movement of the pendulum vibration around the nodes due to the bending vibration acts on the slide plate 3 of the movable frame 2. Therefore, this causes the movable frame 2 to move forward and backward in the central axis direction.

If the ultrasonic motor is configured as in the first embodiment, the vibrator 12 is placed in the cutout hole 1d of the fixed frame 1, and the supports 13a to 13c are connected to the fixed frame 1 and the movable frame 2. Since it is placed in the gap between the two, the hollow linear ultrasonic motor can be configured very compactly. In addition, the holder 8 can be manufactured by pressing a thin plate, and has a channel shape (
By forming it in a U-shape, rigidity can be maintained even with a thin plate, which is effective in downsizing the ultrasonic motor. Furthermore, by making the notch width of the receiving portion 8a of the holder 8 smaller than the outer diameter of the mounting groove 7a of the support pin 7, it is possible to attach and detach the vibrator 12 with a single touch, similar to a C-ring type retaining ring. It is easy to assemble. Further, since the inner diameter of the receiving portion 8a is larger than the outer diameter of the mounting groove portion 7a by a margin, the bending vibration of the bending vibrator 11 is not hindered, and the motor efficiency is high.

Furthermore, in the case of this embodiment, since two vertical vibrators 4 are used, the support of the movable frame 2 becomes more stable. That is, since one of the two vertical vibrators 4 is always in contact with the upper surface of the slide plate 3 of the moving frame 2 even during motor operation, the moving frame 2 is always pressed against the support 13b. This is because the movable frame 2 is always kept at a stable position relative to the fixed frame 1.

Furthermore, in this embodiment, the supports 13a to 13c are arranged symmetrically in three rows at positions facing the vibrator 12, but this is because only one row of the central supports 1.3b is sufficient for the holding function. Of course, only two rows of supports 13a and 13c may be used. Furthermore, in the above embodiment, the support body is also placed in the gap between the movable frame 2 and the fixed frame 1 above the central axis 0, so that the vibrator 12 is moved only by the support body without being involved in holding the movable frame 2. The frame 2 may also be supported. In this way, when an external force or the like that causes the central axis of the movable frame 2 to swing is applied, a large pressure force is not directly applied to the vibrator, and the vibrator is protected.

FIG. 3 shows a modification of the pressing holding portion of the holder 8 in the above embodiment. In this modification, the screw 10 for fixing the holder is constituted by a stepped screw IOA, and a spacer 14 for pressure regulation is used.

With this configuration, the large-diameter stepped shaft portion 10Aa of the stepped screw 10A can be fitted into the opening 8C of the holder attachment fixing member 8b with high accuracy, and the arrangement position of the vibrator 12 can be adjusted with higher precision. can be decided. The ultrasonic vibrations generated by the vibrator 12 are strong, and as shown in FIG. 2 above,
When the holder 8 is fixed so that the screw 10 is loosely engaged with the opening 8C, the vibrator 12 generates unnecessary vibration due to the looseness that occurs in the loosely engaged portion, reducing motor efficiency and causing noise. An audible sound occurs. Therefore, when holding the vibrator 12 using non-stepped screws 10 as shown in FIG. be.

However, as shown in the modified example in Fig. 3, if the stepped screw 10A is used, the stepped shaft 10Aa will be fixed so as to butt against the fixed frame 1, so if the screw IOA is sufficiently tightened, the screw IOA and the fixed frame 1, the screw IOA is fixed to the fixed frame 1 with sufficient holding force.

On the other hand, the pressing force of the vibrator 12 on the top surface of the slide plate 3 is
If the settings are not set with sufficient precision, the motor output may become unstable, efficiency may be reduced, or audible noise may occur. Therefore, in the modification shown in FIG. 3 above, the longitudinal vibrator 4
The flat part 1 of the fixed frame 1 is in contact with the slide plate 3.
Since a gap S is formed between the do and the mounting fixing part 8b, use this to attach the donut plate-shaped pressure regulating spacer 14.
is inserted into the stepped shaft portion 10Aa of the screw IOA and arranged between the disc spring 9 and the head of the screw IOA, and the pressing force of the spring 9 can be adjusted by changing the thickness of this pressure adjusting spacer 14. The pressing force of the vibrator 12 against the slide plate 3 is adjusted optimally.

Furthermore, in this modification, once the set pressure is adjusted, the setting will not deviate.

As described above, according to the modification shown in FIG. 3, the vibrator 12 can be assembled to the fixed frame 1 more reliably and with higher precision, and the pressing force of the vibrator against the slide plate 3 can also be applied accurately and precisely. Since the setting can be made, it is possible to provide a stable and highly efficient holder mounting structure that does not generate audible motor noise.

In the above embodiments and modifications, the disc spring 9 is used as the spring for attaching the holder; however, other elastic bodies such as a coil spring or a plate spring may be used, or the fixing part of the holder 8 8b may be formed as a cantilevered leaf spring, or the mounting and fixing portion 8b may be used as a spring. Furthermore, the mounting fixing portions 8b are provided at two locations symmetrically in the width direction of the transducer 12, but it goes without saying that they may be provided at two or more locations, and their extending direction also matches the direction of the transducer 12. It may be in the longitudinal direction of the plate, and if the position where the vibrator 12 is pressed against the slide plate 3 and the position where the support body is placed are momentarily suspended, the mounting fixing portions 8b do not need to be provided symmetrically. .

FIGS. 4(A) and 4(B) are cross-sectional views of an ultrasonic motor showing a second embodiment of the present invention. This second embodiment is actually configured to move the photographing lens of a camera in the direction of the optical axis of the camera for focusing and zooming using the ultrasonic motor of the present invention. Lens 17 is fixed.

The ultrasonic motor of the second embodiment differs from the ultrasonic motor of the first embodiment in that two ultrasonic transducers 12A and 12B are disposed on the fixed frame IA, and that The body is formed of one row of supports 13, and the holding portion of this support 13 on the fixed frame IA side is constituted by a holding body 15 separate from the fixed frame IA.

That is, both of the two ultrasonic transducers 12A and 12B have the same structure as that of the first embodiment, and are arranged in the circumferential direction from a position opposite to the position where the support body 13 is disposed. They are placed at equal distances from each other. Also,
The holding body 15 is tightly fitted into an opening IAa cut out in the lower central part (in FIG. 4) of the fixed frame IA, and is fixed to the fixed frame IA with screws 16, thereby forming a part of the fixed frame IA. A straight groove IAb consisting of a partially arcuate recess for holding the support body 13 is bored in the direction of the central axis on the inner circumferential surface thereof. Then, in this straight groove IAb and the straight groove 2Ab of the moving frame 2A,
A support body 13 consisting of a plurality of bearing balls is provided.

According to the second embodiment configured in this way, the vibrator 12
A, 12B and the support body 13 are arranged in a well-balanced manner at approximately three equal parts of the gap between the fixed frame IA and the movable frame 2A, so that the movable frame 2A is fixed as in the first embodiment. It is possible to accurately position the frame IA, and in addition, since a plurality of transducers 12A and 12B are used in this second embodiment, the movable frame 2A holding the photographing lens 17 can be positioned in the optical axis direction. The driving force to advance and retreat will be doubled. However, in terms of space, it requires approximately the same space as the ultrasonic motor of the first embodiment described above, and can be constructed in a small size despite its high output.

Further, the holding body 15 that holds the support body 13 is attached to the fixed frame IA.
The vibrator 12A is provided separately from the vibrator 12A and is fixed to the fixed frame IA with screws 16.

The position of the support body 13 can be finely adjusted and assembled with respect to the attachment position of the support body 12B, and manufacturing errors of the movable frame 2A, fixed frame IA, etc. can be corrected.

Furthermore, the straight grooves of the movable frame and the straight grooves of the fixed frame that the support body 13 comes into contact with need to be made of a wear-resistant material, but if they are made of a separate holder 15 as in this second embodiment, It is no longer necessary to make the entire fixed frame of a wear-resistant material, and only the holder 15 needs to be made of a wear-resistant material, which is a remarkable effect.

FIG. 5 is a sectional view of an ultrasonic motor showing a third embodiment of the present invention. This third embodiment differs from the ultrasonic motor of the first and second embodiments in that the fixed frame IB and the movable frame 2
The point B is that it is formed of a hollow rectangular cylinder as shown in cross section in FIG.

And the vibrator 12. The holder 8 and the like are constructed in exactly the same way as those of the first embodiment shown in FIGS. 2 and 3 above, and have a cutout hole IBd bored in one side of the rectangular cross section of the fixed frame IB, for example, in the center of the upper side. Disposed within the disc spring 9. Pressure regulating spacer 14. The tip of the vertical vibrator 4 is placed in pressure contact with the top surface of the slide plate 3 by a screw 10 screwed into the top surface of the fixed frame IB through the holder opening 8c.

On the other hand, straight grooves IBa and IBb are provided in both sides of the inner surface of the lower side of the fixed frame 1B, which faces the vibrator 12 arranged in this manner, as in the first embodiment. The relationship between the drilling positions of the straight grooves IBa and IBb and the mounting position of the vibrator 12 is as follows:
, IBb are arranged to be symmetrical. Furthermore, straight grooves 2Ba and 2Bb are provided on the outer surface of the lower side of the moving frame 2B opposite to the straight grooves IBa and IBb, and these straight grooves 28a and 2Bb and the straight groove IBa.

Support bodies 13d and 13e, which are guide members each consisting of a plurality of bearing balls, are disposed within IBb.

Even with this configuration, the ultrasonic motor operates in exactly the same way as the ultrasonic motor of the first embodiment.

If the fixed frame IB has a flat portion as in the third embodiment, it is possible to easily attach the vibrator having a flat plate shape.

In addition, in conventional camera lens frames, when driving the lens frame, it is necessary to minimize play between the movable frame and the fixed frame in order to increase the positional accuracy of the frames. However, if configured as in this embodiment, a straight groove IBa.

IBb and 2Ba, 2Bb and support 13d.

If 13e is precisely processed, the moving body 2B and fixed frame I
B can be precisely positioned, so the shapes of the fixed frame and the movable frame can be freely formed. Furthermore, in this embodiment, the slide plate 3 is provided separately from the moving frame 2B, but
If the moving frame 2B is made of a wear-resistant material, the slide plate 3 does not need to be provided. Further, when the rectangular tube frame of the above embodiment is used as a camera lens frame, the lens itself can be made rectangular, thereby making it possible to reduce the size of a lens having a rectangular visual field such as a film or a finder visual field.

Next, FIGS. 6 and 7 respectively show modified examples of the fixed frame IB in the ultrasonic motor of the third embodiment. That is, the fixed frame IC shown in FIG. 6 is formed by forming a part (upper part) of a hollow cylinder into a flat part ICc, and a notch hole ICd is provided in the center of the flat part ICc.
The straight grooves ICa and ICb are formed symmetrically with respect to the straight grooves ICa and ICb. Further, the fixed frame ID shown in FIG. 7 is formed of a hollow polygonal cylinder, for example, a hexagonal cylinder, and a notch hole IDd is provided in the center of the upper flat part IDc, and this notch hole I
Straight grooves IDa and ID are located symmetrically with respect to Dd.
b.

The shape of the movable frame corresponding to the fixed frame IC, ID shown in these modified examples may be formed by having a cross-sectional shape similar to that of the fixed frame IC, ID, or the fixed frame IC, Other different shapes may be used as long as they can be accommodated on the inner peripheral surface of the ID. Furthermore, it goes without saying that the shape of the hollow frame body is not limited to those shown in FIGS. 5 to 7 above, but may be a combination of other curved lines or straight lines, as long as it has a flat part. It is.

Incidentally, in each of the above examples, the supports 13.1'3a to 13
Although bearing balls were used as C113d and C13e, it goes without saying that bearing rollers may also be used.

[Effects of the Invention] As described above, the ultrasonic motor according to the present invention is ideal as a drive source for things that require linear motion, such as camera lenses, and can be used to move hollow movable frames and fixed frames inside lens barrels. It can be configured to fit into the smallest space.

Moreover, according to the present invention, what holds the movable frame is a support member that is a guide member provided between the fixed frame and the movable frame;
With only the ultrasonic transducer for driving, the energy loss directly lost through the support structure is minimal. Since the movable frame is directly driven by the vibrator, it has the advantage of extremely high motor efficiency, and since the movable frame is always held in pressure contact with the support, the fixed frame of the movable frame This has the remarkable effect of maintaining extremely high positional accuracy.

[Brief explanation of drawings]

1(A) and (B) are cross-sectional views of an ultrasonic motor showing a first embodiment of the present invention, and FIG. 2 is a mounting structure of an ultrasonic vibrator in the ultrasonic motor of the first embodiment. FIG. 3 is an enlarged sectional view of essential parts showing a modified example of the mounting structure of the ultrasonic transducer, and FIGS. 4(A) and (B) show a second embodiment of the present invention. FIG. 5 is a cross-sectional view of an ultrasonic motor showing a third embodiment of the present invention. FIGS. 6 and 7 are modifications of the fixed frame in the third embodiment, respectively. FIG. 1, IA, IB, IC, ID・old and old-fixed frame (fixed member) 2.2A, 2B town old...movable frame (movable member) 4...
......Longitudinal vibrator 5...Piezoelectric body 6...Elastic body 11...・Bending vibrator 12... Vibrator

Claims (2)

[Claims] (1) A vibrator supported by a fixed member, including a bending vibrator that generates bending vibration by applying a high-frequency voltage, and a longitudinal vibrator that generates longitudinal vibration in the amplitude direction of the bending vibration; A movable member that presses against the tip of the longitudinal vibrator and moves relative to the fixed member due to the combined vibration of the rocking motion due to the bending vibration and the longitudinal vibration generated at the tip, and a space between the fixed member and the movable member. a guide member that is provided and guides the movement of the movable member relative to the fixed member; and at least one of the fixed member and the movable member is a hollow frame having a central axis parallel to the moving direction of the movable member. An ultrasonic motor featuring: (2) Claim 1 characterized in that the moving member is formed into a hollow frame having at least a part of it a flat surface parallel to the moving direction, and the flat surface is pressed against the tip of the vertical vibrator.
Ultrasonic motor as described.