JPH05268780A - Driver - Google Patents

Abstract

PURPOSE:To block transmission of manual driving torque to an ultrasonic motor by providing a power transmission system, located closer to the motor than a power transmission gear interlocked with power drive/manual drive switching operation, with a slip clutch mechanism. CONSTITUTION:An output gear 41, a double-reduction gear 31, a pulse gear 33, and a switching gear 30 rotate as a manual operating member rotates to transmit rotary power to a second friction gear 25. First and second friction gears 24, 25 are friction coupled and the friction part thereof slips before a rotor 3 slips with respect to a vibration resilient body 1 of an ultrasonic rod motor under that state. Since the rotor of ultrasonic motor is not rotary driven forcibly even if the motor is inadvertently driven manually with the power transmission being set in motor drive, the motor is protected against damage.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive unit (or drive unit) suitable for mounting on a small device such as a portable camera, and particularly uses an ultrasonic motor (vibration wave motor) as a power source. The present invention relates to a drive device having a structure capable of switching between power drive and manual drive.

[0002]

2. Description of the Related Art Recently, an interchangeable lens barrel for a single-lens reflex camera is equipped with an autofocus device and a power zoom device. As these devices, a power drive and a lens for driving a lens by a power generated by a motor are used. A lens driving device capable of manually driving the lens is provided. The lens driving device includes a motor that is a power source,
A reduction gear mechanism for transmitting the power generated by the motor to a lens holding frame or the like, and the reduction gear mechanism operates to operate a power drive / manual drive switching operation member provided outside the lens barrel. A power transmission system switching gear (hereinafter abbreviated as a shift gear) that is shifted in an interlocking manner and a power transmission system switching gear that is provided closer to the output shaft of the reduction gear mechanism than the shift gear and does not transmit power (that is, from the motor to the lens). A gear (not in the mechanical coupling mechanism), and a known encoder plate is attached to the gear, and the coding pattern formed on the encoder plate is exchanged with an electric signal. A photoelectric detector for is arranged near the reduction gear mechanism. When the lens is power-driven in the lens barrel having the known lens driving device having the above-described configuration, when the switching operation member is operated to the power driving position, the shift gear is shifted and the gear mechanism is operated. When the motor is driven after that, the power generated by the motor is transmitted to the lens holding frame via the output shaft of the gear mechanism, and the lens holding frame is moved by the power of the motor. Be done. At this time, since the encoder plate mounting gear is also rotated by the power of the motor, the amount of movement of the lens and the position change of the lens are detected by the photoelectric detector as an electric signal.

On the other hand, when the lens is manually driven in the lens barrel, when the switching member is operated to the manual drive position, the shift gear is shifted from the power transmission position to the power non-transmission position, and then the lens holding is carried out. When the manual operation ring linked to the frame or the lens holding cylinder is manually rotated, the lens holding frame moves to manually drive the lens. Then, at that time, the rotation of the manual operation ring or the like is transmitted from the output shaft of the reduction gear mechanism to the encoder plate mounting gear, so that the amount of lens movement and lens position change at the time of manual driving are also controlled by the photoelectric detector. It is detected as an electric signal.

[0004]

An ultrasonic motor (vibration wave motor) which the applicant of the present invention has already put into practical use in an interchangeable lens for a camera has a large low-speed torque and can reduce a reduction gear, so that the electromagnetic drive of the related art is used. It has many advantages such as smaller size and quieter operation than a motor, so recently other manufacturers are planning to install it in devices such as cameras. When an ultrasonic motor is used as a power generation source, there are the following problems, which need to be solved.

(A) An ultrasonic motor, as is well known, has a stator (vibration generator) and a rotor (moving body).
Power cannot be generated unless and are pressed against each other with a considerable pressing force. When an ultrasonic motor is used as the power generation source of the above-mentioned known lens driving device, for example, when the user accidentally moves the shift gear to the power non-transmission position and manually drives the shift gear. , A manual drive torque is applied to the rotor of the ultrasonic motor via the reduction gear mechanism, so that the rotor is forcibly rotated, but the stator is held so as not to rotate. There is a risk of problems such as scratches on the press contact end surface, damaging the motor and deteriorating its performance, and rubbing noise generated by the rotor and the stator rubbing against each other to give an unpleasant feeling. is there.

(B) In recent cameras, not only the camera body but also the interchangeable lens is downsized as compared with the conventional products.
The motor is also mounted close to the grease using portion such as the helicoid coupling portion of the lens barrel, but assuming that the ultrasonic motor is mounted on the conventional device having such a structure, the grease using portion is changed from the grease using portion to the ultrasonic motor. There is a risk that grease may invade into the ultrasonic motor, resulting in a significant deterioration in the performance of the ultrasonic motor. (As already explained, an ultrasonic motor cannot generate power unless there is considerable friction between the rotor and stator because they are pressed against each other with considerable pressure. This is because not only the friction between the two will decrease, but also the rotation of the rotor will become significantly unstable. (C) In the above-mentioned conventional lens driving device, the motor is rotated to drive the lens by the motor driving. In this case, since no load is applied to the encoder plate mounting gear, there is backlash in the meshing portion between the power transmission gear of the gear mechanism and the encoder plate mounting gear, but the encoder plate mounting gear is small. It will rotate while rattling. Therefore, when the resolution of the encoder is fine (for example, when 1 to 2 pulses are output from the photoelectric detector due to the backlash), the lens movement amount detection accuracy deteriorates, and as a result, the accuracy of autofocus and zooming is reduced. Will worsen and result in degraded camera performance.

On the other hand, during manual driving, the shift gear is moved to the power non-transmitting position and the load of the motor power transmission system is not applied to the manual operating ring, so that the manual operating ring can be moved extremely lightly, but on the other hand, However, since the resistance applied to the manual ring is too small, a delicate operation becomes difficult, and an appropriate operation feeling cannot be obtained, which is a problem that the user hates to use.
Therefore, in the past, in order to improve the feeling of operation during manual drive, a viscous oil such as grease was injected into the rotating part of the manual operation ring, etc. It has the drawback that it is difficult to manage, and that an accident that grease may flow into other areas where grease cannot adhere is likely to occur.

An object of the present invention is to solve the above-mentioned problems (a) to (c) and to use an ultrasonic motor as a drive source without damaging the ultrasonic motor.
A drive device or a drive unit in which the control accuracy of the driven object is improved as compared with the conventional device, a good operation feeling is obtained for the manually operated member when the driven object is manually driven, and grease or the like does not enter the ultrasonic motor. Is to provide.

[0009]

In order to solve the above-mentioned problems, in the drive unit according to the present invention, a slip clutch mechanism is provided in the power transmission system at a position closer to the motor than the shift gear, and the manual drive torque exceeds The reduction gear mechanism and the power generation part of the ultrasonic motor, which are prevented from being transmitted to the ultrasonic wave motor, are housed in a housing to isolate the power generation part of the ultrasonic motor from other grease-using parts. Manually driven by mounting the encoder mounting gear on the stationary support shaft of the gear so as to generate a predetermined frictional resistance, which eliminates the risk of grease or the like flowing into the power generation part of the ultrasonic motor. Occasionally, resistance is applied to the manually operated ring, etc., and friction resistance is added to the gear when the encoder mounting gear is driven from the power transmission system. Characterized in that so as to eliminate the influence of the backlash of the meshing portion of the gears, solutions and the like is applied by.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the driving device (drive unit) according to the present invention is applied to an interchangeable lens for a single-lens reflex camera will be described below with reference to FIGS.

The structure of the device of the present invention will be described below by dividing it into parts such as an ultrasonic motor part and a power transmission mechanism.

<Structure of ultrasonic motor (rod-shaped ultrasonic motor)> In FIGS. 1 to 4, reference numeral 1 is a vibrating elastic body of the rod-shaped ultrasonic motor, and the vibrating elastic body 1 is a cylindrical body having an intermediate portion. A female thread 1a is formed in the central hole, which is screwed into the threaded portion 2a of the conductive shaft 2. The vibration elastic body 1 is made of a conductive material, and one end surface 1b of the vibration elastic body is pressed against one end surface 3a of the rotor 3. The rotor 3a is also a tubular body, and is fitted to the outer periphery of the spring holding member 17, which is also a tubular body. Reference numeral 4 denotes a conductive retainer having a central hole 4a, which is pressed against the piezoelectric element described later by the head of the shaft 2. Reference numerals 5 to 8 are annular disk-shaped piezoelectric elements as an electro-mechanical energy conversion element composed of, for example, PZT.
Constitutes the A phase, and the piezoelectric elements 7 and 8 constitute the B phase. In this embodiment, various phases of A phase and B phase are composed of two piezoelectric elements, but the number of piezoelectric elements of each phase may be only one.

The diameter of the center hole of each of the piezoelectric elements 5 to 8 described above is larger than the outer diameter of the screw portion 2a of the shaft 2, and each piezoelectric element is polarized in the circumferential direction. Reference numeral 9 is a sensor also composed of a piezoelectric element, and the sensor 9 is a machine for detecting the vibration state of the stator including the vibrating elastic body 1 and the pressing body 4.
It has an electric energy conversion function. The diameter of the central hole of the sensor 9 is also larger than the outer diameter of the threaded portion 2a of the shaft 2 so as not to contact the threaded portion 2a of the shaft 2. 10-12
Is an electrode that supplies an alternating voltage of a first phase to the piezoelectric elements 5 and 6, and 12 to 14 are alternating voltage having a second phase different from the phase of the alternating voltage applied to the electrodes 10 to 12. Electrodes supplied to 7 and 8. The ground electrode 12 is connected to the ground electrode 14 via the threaded portion 2a of the shaft 2.
Electrically connected to. Further, the ground electrode 10 is connected to the ground electrodes 12 and 1 via the vibration elastic body 1 and the shaft 2.
4 is electrically connected. Reference numerals 14 and 15 denote electrodes for outputting an electric signal from the sensor 9 according to the vibration of the vibrating elastic body 1 as the ultrasonic transducer (stator) and the pressing body 4, and the output signal is an oscillator control circuit (not shown). Is to be transmitted to. Reference numeral 16 denotes an insulating washer provided between the shaft 2 and the presser body 4, and the washer is the presser body 4
This is for preventing the vibrating elastic body 1 and the vibrating elastic body 1 from being short-circuited, that is, at the same potential, via the shaft 2.

The rotor 3 described above has an axis Z when the vibrating elastic body 1 as an ultrasonic vibrator (stator) and the pressing body 4 vibrate in response to an AC voltage supplied to the piezoelectric element.
Rotate around. Reference numeral 17 is a spring holding member that receives a pressure spring 19 described later and is fixed to the rotor 3. 18
Is a rotation output member having a gear portion 18a, and has a protrusion 18b so as to be integrated with the spring holding member 17 in the rotation direction and free in the thrust direction, and the groove portion 17a corresponding to this protrusion 18b. Is a spring holding member 17
It is provided in. 19 is a pressure spring, which is provided between the rotation output member 18 and the spring holding member 17, and
Is pressed against a vibrating elastic body 1 as an ultrasonic transducer (stator). Reference numeral 20 denotes a bearing that rotatably supports the rotation output member 18 and the rotor 3. Reference numeral 21 is a support member for fixing the rod-shaped ultrasonic motor to the mounting member 38, and is fixed to the mounting member 38 with screws 22 and 23. In assembling the ultrasonic motor, the support member 21 is fitted to the shaft 2 and abutted against the flange portion 2b of the shaft 2 and then fixed to the shaft 2 with an adhesive. As a result, the assembly of the rod-shaped ultrasonic motor is completed with the pressing state of the pressing spring 19 being maintained via the bearing 20 and the rotation output member 18.

<Structure of Power Transmission Mechanism Connected to Ultrasonic Motor> Reference numeral 24 is a first friction gear in which the gear portion 18a of the rotation output member 18 of the rod-shaped ultrasonic motor meshes. 25 is the second
It is a friction gear, and the gear 25 includes two friction plates 2
6 and 27, a compression coil spring 28, and a spring retainer 29, the friction coupling mechanism normally rotates integrally with the first friction gear 24, and the switching gear 3 to be described later.
Although the rotation is transmitted to 0, the frictional force of the friction coupling mechanism is generated between the vibrating elastic body 1 of the rod-shaped ultrasonic motor and the rotor 3 when the second friction gear 25 is rotated from the switching gear 30 side described later. Since it is set to be larger than the frictional force, the first friction gear 24
On the other hand, the second friction gear 25 slips, and the first friction gear 24 and the rotor 3 do not rotate. Reference numeral 30 denotes a switching gear that operates in the thrust direction when the automatic manual focus adjustment mode is switched, meshes with the second friction gear 25, and has a fitting portion 45a of a mode switching spring 45, which will be described later, fitted into the groove portion 30a. 31 is a transmission gear that meshes with the switching gear 30. 32 is a gear portion 3 that meshes with the transmission gear 31.
It is a two-stage gear having 2a, and a pulse gear 33 described later meshes with the other gear 32b. Reference numeral 34 denotes a pulse plate, which is fixed to the pulse gear 33. When a pulse of the pulse plate 34 is read by the photocoupler 35, movement of a driven object (focus lens L described later) rotationally driven by a gear 41b described later and The position can be detected. 37 is a fixed member, and has a shaft that supports each gear. Three
Reference numeral 8 denotes a mounting member, which receives the gear support shafts of the fixing member 37, and is fixed to the fixing member 37 by screws 39 and 40. The fixing member 37 or the mounting member 38
Further, the photo coupler 35 is fixed by adhesion or the like.

A pressure contact portion between the rotor 30 of the ultrasonic motor and the vibrating elastic body 1 and a peripheral wall portion 37a surrounding the power transmission mechanism are formed on the outer peripheral portion of the fixing member 37. When 38 and 38 are coupled with screws 39 and 40, a housing that houses the power transmission mechanism and the power generation part of the ultrasonic motor is formed by the fixing member 37 and the mounting member 38, and the housing The power generation part of the sonic motor is shielded from a grease using part (not shown) on the outside of the housing. In the device of the present invention, no grease or lubricating oil is used for each gear constituting the power transmission mechanism, and each gear does not need a lubricant and has a low coefficient of friction (for example, a fluororesin coating). Alternatively, it is made of an impregnated material or a polyacetal resin).

The above-described pulse gear 33 is formed of a material having a low bending rigidity and a low friction coefficient, for example, polyacetal resin, and an elastic portion 33a having at least two legs is integrally formed. The elastic portion 33a
Is elastically pressed against the shaft portion 37b of the fixing member 37 in the radial direction, and imparts a weak frictional resistance force to the rotation of the pulse gear 33 itself. Reference numeral 41 is an output gear having a gear portion 41a that meshes with the gear portion 32a of the two-stage gear 32, and also has a gear portion 41b that meshes with a gear portion 42a of a manual operation member (rotary cylinder) 42 described later.

<Structure of an interchangeable lens barrel in which the drive unit (drive unit) of this embodiment is mounted as a lens drive unit> In FIG. 2, reference numeral 42 denotes a manual operation member which is a rotary barrel for focusing, and a focus lens. L
Holding Reference numeral 43 denotes a fixed cylinder, which is a manual operation member 4
It has a helicoid 43a that is helicoid-bonded with the second helicoid portion 42b. Reference numeral 44 is a mode switching member for switching between automatic focus adjustment and manual focus adjustment. Reference numeral 45 is a mode switching spring fixed to the mode switching member 44 with a screw 46, and the spring 45 is the groove portion 30a of the switching gear 30.
And a click portion 45b for clicking the motor drive (automatic focusing) mode position and the manual drive mode position at the other end. Reference numeral 47 denotes a support member that fixes the fixed cylinder 43, and the support member 4
Reference numeral 7 has click grooves 47a and 47b into which the click portion 45b of the mode switching spring 45 is inserted, and the fixed cylinder 43 is fixedly supported by screws or the like. In this configuration, when the click portion 45b is inserted into the click groove 47a, the motor drive (automatic focus) mode is set, and when the click portion 45 is inserted in the click groove 47b, the manual drive (manual focus) mode is set.

The driving device of the present embodiment shown in FIG. 1 is fixed to the fixed barrel 43 with screws 48 as shown in FIG.

<Operation> Next, the operation will be described. 1 and 2
Indicates the state when the motor drive (automatic focusing) mode is set,
FIGS. 3 and 4 explain the operation when the lens barrel is moved using the rod-shaped ultrasonic motor in the motor drive (automatic focus) mode in FIGS. 1 and 2 when the manual drive (manual focus) mode is set. To do. In this state, in the mode switching member 44, the click portion 45b of the mode switching spring 45 has the click groove 47.
It is located closer to the left side of the figure because it is inserted into a. On the other hand, the switching gear 30 is gear-connected to the second friction gear 25 by the fitting portion 45a of the mode switching spring 45 as shown in FIG. Further, since the mode switching member 44 is located on the left side as shown in FIG. 2, it is in a circuit state in which a drive signal of a drive circuit (not shown) can be sent to the rod-shaped ultrasonic motor. When a lens drive signal is received from a drive circuit (not shown) in this state, the electrode 1
AC voltages 0 to 14 are supplied to the A-phase piezoelectric elements 5 and 6, and to the B-phase piezoelectric elements 7 and 8, respectively.
Then, the vibration generated in the piezoelectric elements 5 to 8 excites the two end surfaces of the vibrating elastic body 1 and the pressing body 4. That is, due to the phase difference between the AC voltages applied to the set of piezoelectric elements, progressive vibration that moves in the rotational direction about the axis Z is generated at the end faces of the vibrating elastic body 1 and the pressing body 4. Therefore, the rotor 3 pressed against the vibrating elastic body 1 forming the ultrasonic vibrator (stator) makes a rotational motion. As a result, the rotation output member 18 integrated in the rotational direction with the spring holding member 17 fixed to the rotor 3 rotates together with the rotor 3. The rotation is transmitted to the first friction gear 24, and the second friction gear 25 frictionally coupled to the first friction gear 24 also rotates integrally with the gear 24. Then, the rotation of the gear 25 is changed by the switching gear 3
0, the transmission gear 31, the two-stage gear 32, and the output gear 41 to be transmitted to the manual operation member (rotary cylinder) 42. The focus lens L is arranged on the manual operation member (rotary cylinder) 42, while the helicoid portion 43a and the helicoid portion 42b of the fixed cylinder 43 are helicoidally coupled, so that the manual operation member (rotary cylinder) 42 rotates. While moving forward and backward, you can focus. On the other hand, with the rotation of the two-stage gear 32, the pulse gear 33 meshing with the gear portion 32b of the two-stage gear 32 also rotates. By this rotation, the position and speed of the focus lens L are detected by the pulse plate 34 and the photocoupler 35, and when the focus lens L is moved to a predetermined position, the supply of the AC voltage to the rod-shaped ultrasonic motor is stopped. You can automatically focus. The pulse gear 33 is formed of a material having a low bending rigidity and a low friction coefficient, such as polyacetal resin, and is in radial contact with the shaft portion 37a of the fixing member 37 by the elastic portion 33a. Therefore, the pulse gear 33 itself is weak. It will rotate while receiving frictional resistance. When the pitch of the pulse plate 34 is small, one or two pulses of the pulse plate 34 are generated due to the backlash amount due to the meshing of the gear portion 32b of the two-stage gear 32 and the gear portion of the pulse gear 33. In the conventional lens driving device, a detection error occurs because the pulse gear rotates while rattling by the amount of this backlash during gear rotation. The present invention realizes a drive device that does not generate an erroneous pulse by applying a weak frictional resistance force to the pulse gear 33.

Next, referring to FIGS. 3 and 4, manual driving (manual focusing)
The operation when the manual operation member 42 is rotated in the mode will be described. In this state, the mode switching member 44 is located closer to the right side of the drawing because the click portion 45b of the mode switching spring 45 is inserted into the click groove 47b. On the other hand, the fitting portion 45a of the mode switching spring 45 causes the switching gear 30 to move to the second friction gear 2 as shown in FIG.
It is held in that state after disconnecting the gear connection with the gear 5. Further, since the mode switching member 44 is located closer to the right side as shown in FIG. 4, the drive signal of the drive circuit (not shown) is not transmitted to the rod-shaped ultrasonic motor. When the manual operation member 42 is rotated in this state, the helicoid couplings 42b and 43a allow the manual operation member 42 itself to rotate and move back and forth for focusing. On the other hand, when the manual operation member 42 is rotated, the output gear 41 that meshes with it rotates, and the two-stage gear 32, the transmission gear 31, and the switching gear 30 that mesh with it also rotate. Further, the rotation of the two-stage gear 32 also rotates the pulse gear 33. Since a weak frictional resistance force is applied to the pulse gear 33 as described above, when the manual operation member 42 is rotated, an appropriate resistance torque is felt in the manual operation member 42 itself. This resistance torque has, for example, 16 teeth for the pulse gear 33, 38 teeth for the gear portion 32b of the two-step gear 32, 22 teeth for the gear portion 32a,
The gear portion 41a of the output gear 41 has 27 teeth and the gear portion 4
1b has 10 teeth, the gear portion 42a of the manual operation member 42
If the number of teeth is 135, the pulse gear 33 has 1gc
When friction resistance of m is applied, 1gcm x 135
/ 10 × 27/22 × 38/16 = 39 gcm,
The weak frictional resistance force of the pulse gear 33 causes a resistance torque of about 40 times on the manual operation member 42. Therefore, since an appropriate resistance torque is applied to the rotation of the manual operation member 42, an operation with a good manual operation feeling, that is, a good manual taste can be obtained. Since the switching gear 30 is disconnected from the second friction gear 25, the rotation of the manual operation member 42 does not affect the rod-shaped ultrasonic motor.

Next, referring to FIGS. 1 and 2, the operation when the manual operation member 42 is erroneously operated in the motor drive (automatic focusing) mode will be described. Since the positions of the gears and the like are the same as those in the motor drive (automatic focusing) mode, description thereof will be omitted. When the manual operation member 42 is rotated, the output gear 41, the two-stage gear 31, the pulse gear 3 are rotated along with the rotation.
3. The switching gear 30 is rotated. Then, the rotational force is transmitted to the second friction gear 25. On the other hand, the first friction gear 24 and the second friction gear 25 are frictionally coupled to each other, and in this state, the rotor 3 slides on the vibrating elastic body 1 of the rod-shaped ultrasonic motor when rotated from the second friction gear 25 side. Before the first friction gear 24 and the second friction gear 25
The friction part of is configured to slide. Therefore, even if the rotational force is transmitted to the second friction gear 25, the first friction gear 24 does not rotate and slides at the friction portion, so there is no influence on the rod-shaped ultrasonic motor.

[0023]

As described above, according to the driving device of the present invention, the following effects can be obtained.

(I) Even if the power transmission mechanism is set to drive the motor by mistake and the manual drive is erroneously performed, the rotor of the ultrasonic motor is not apt to be rotationally driven, so that the motor is damaged. It is possible to realize a drive device that can be prevented and can use an ultrasonic motor.

(II) Since the power generation part of the ultrasonic motor is housed in the housing and shielded from the grease using part, there is no fear that grease or the like will enter the mutual pressure contact surface between the rotor and the stator of the ultrasonic motor. There is no risk of causing performance deterioration of the motor.

(III) Since friction resistance is given to the detection rotary member (or the no-load rotary member) which is interlocked with the manual drive system, the operation feeling of the manual operation member at the time of manual drive is improved and it is easy to use. It was

Further, when the motor is driven, the rattling rotation due to the backlash between the detection rotating member and other gears is eliminated, so that highly accurate detection can be performed.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of a driving device according to the present invention, and is a longitudinal sectional view of a main part of a lens driving device of an interchangeable lens for a single lens reflex camera configured by applying the present invention (where the driving device is a motor). The figure which shows the state set to the drive mode).

FIG. 2 is a cross-sectional view of a main part of an interchangeable lens equipped with the apparatus of FIG. 1, showing a state corresponding to the state of FIG.

FIG. 3 is a diagram showing a state in which the drive device shown in FIG. 1 is set for manual drive.

FIG. 4 is a diagram showing a state in which the interchangeable lens shown in FIG. 2 is set to a manual drive mode.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Vibration elastic body (stator) 3 ... Rotating member (rotor) 4 ... Pressing body (stator) 5-9 ... Piezoelectric element (electrical-mechanical energy exchange element) 10-15 ... Electrode plate 18 ... Rotation output member 19 ... Addition Pressure spring 24 ... First friction gear 25 ... Second friction gear 30 ... Switching gear 31 ... Transmission gear 32 ... Two-stage gear 33 ... Pulse gear (encoder means) 34 ... Pulse plate 35 ... Photo coupler 37 ... Fixing member 41 ... Output gear 42 ... Manual operation member 44 ... Mode setting member 45 ... Mode switching spring L ... Focus lens

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[Procedure amendment]

[Submission date] March 25, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be amended] Claims

[Correction method] Change

[Correction content]

[Claims]

Claims (8)

[Claims] 1. An ultrasonic motor having a stator made of a vibrating elastic body and a rotor pressed against the stator at a predetermined pressure, a power transmission mechanism connected to the rotor, and when the ultrasonic motor is not driven. Clutch means for automatically preventing the reverse drive force applied to the power transmission mechanism from the load side to be transmitted to the rotor, and the transmission limit torque of the reverse drive force in the clutch means is A drive device, which is set to a value lower than a maximum static friction torque between the rotor and the stator when the ultrasonic motor is not driven. 2. An ultrasonic motor having a stator made of a vibrating elastic body and a rotor pressed against the stator at a predetermined pressure, a power transmission mechanism connected to the rotor, and a non-driving state of the ultrasonic motor. The non-load member includes clutch means for automatically preventing reverse drive force applied to the power transmission mechanism from the load side to be transmitted to the rotor, and a non-load member interlocking with the power transmission mechanism. The drive device is characterized in that the member is configured to generate a predetermined low resistance torque when driven by the power transmission mechanism. 3. An ultrasonic motor having a stator made of a vibrating elastic body and a rotor pressed against the stator at a predetermined pressure, a power transmission mechanism connected to the rotor, and mutual pressure contact between the rotor and the stator. A shield for enclosing the power generation part of the ultrasonic motor and the power transmission mechanism including a portion, and a reverse driving force applied from the load side to the power transmission mechanism to the rotor when the ultrasonic motor is not driven. And a clutch means for automatically preventing the power generation section and the power transmission mechanism of the ultrasonic motor from being shielded from the lubricant using section by the shield. A drive device, wherein a transmission limit torque of the reverse driving force is set to a value lower than a maximum static friction torque between the rotor and the stator when the ultrasonic motor is not driven. 4. An ultrasonic motor having a stator made of a vibrating elastic body and a rotor pressed against the stator at a predetermined pressure, a power transmission mechanism connected to the rotor, and mutual pressure contact between the rotor and the stator. A shield for enclosing the power generation part of the ultrasonic motor and the power transmission mechanism including a portion, and a reverse driving force applied from the load side to the power transmission mechanism to the rotor when the ultrasonic motor is not driven. A drive device comprising: a clutch means for automatically preventing the power transmission from being performed; and a low resistance torque generating means that is interlocked with the power transmission mechanism. 5. The drive device according to claim 1, wherein the clutch means is a friction clutch mechanism. 6. The non-load member is a rotating member rotatably fitted on a stationary shaft, and the rotating member is fitted on the stationary shaft at a predetermined fitting pressure. Item 2
Drive. 7. The drive device according to claim 2, wherein the non-load member is a detection member. 8. The drive device is configured as a lens drive device of an optical device with a built-in lens, and a lens holding frame interlocking mechanism and a manual drive operation member can be connected to an output end of the power transmission mechanism. The drive device according to any one of claims 1 to 4, which is characterized in that: