Vibration type motor for guiding movement of a friction member, and lens apparatus and electronic apparatus including said motor

A vibration type motor includes first and second vibrators, a friction member configured to contact the first and second vibrators, a pressure member configured to press the first and second vibrators against the friction member, and first and second guide members configured to guide a relative movement between the first and second vibrators and the friction member. The first and second vibrators are spaced in a direction different from a relative movement direction between the first and second vibrators and the friction member. The first and the second guide member are provided between the first vibrator and the second vibrator in a direction different from the relative movement direction. A pressure center of a pressure applied to the first vibrator and the second vibrator by the pressure member is located between the first guide member and the second guide member.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to a vibration type motor applicable to a lens apparatus etc.

Description of the Related Art

Japanese Patent Laid-Open No. (“JP”) 2015-65809 discloses an ultrasonic motor that includes a vibrator having a piezoelectric element and an elastic body having a protrusion, a friction member configured to move relative to the vibrator due to a high-frequency vibration of the vibrator, and a pressure member configured to press the vibrator against the friction member. The ultrasonic motor disclosed in JP 2015-65809 further includes guide means configured to guide the relative movement between the vibrator and the friction member while receiving the reaction force of the pressure applied to the vibrator. The guide means includes a guide member and a guide groove, and the guide member is engaged with the guide groove and rolls on the guide groove, thereby guiding the relative movement between the vibrator and the friction member.

However, the ultrasonic motor disclosed in JP 2015-65809 applies the pressure of the pressure member to the vibrator inside the three guide members over the entire driving range. Thus, the occupancy range of the guide groove is long in the moving direction of the ultrasonic motor. As a result, the ultrasonic motor in the moving direction becomes larger, and it is difficult to realize a compact ultrasonic motor.

SUMMARY OF THE INVENTION

The present invention provides a compact vibration type motor, a lens apparatus, and an electronic apparatus.

A vibration type motor according to one aspect of the present invention includes a first vibrator and a second vibrator, a friction member configured to contact the first vibrator and the second vibrator, a pressure member configured to press the first vibrator and the second vibrator against the friction member, and a first guide member and a second guide member configured to guide a relative movement between the first and second vibrators and the friction member. The first vibrator and the second vibrator are spaced in a direction different from a relative movement direction between the first and second vibrators and the friction member. The first guide member and the second guide member are provided between the first vibrator and the second vibrator in a direction different from the relative movement direction. A pressure center of a pressure applied to the first vibrator and the second vibrator by the pressure member is located between the first guide member and the second guide member.

A lens apparatus according to another aspect of the present invention includes the above vibration type motor, and an optical system driven by the vibration type motor. An electronic apparatus according to still another aspect of the present invention includes the above vibration type motor, and a target driven by the vibration type motor.

DESCRIPTION OF THE EMBODIMENTS

Referring now to the accompanying drawings, a detailed description will be given of embodiments according to the present invention. In each figure, the same reference numerals are given to the same elements, and a duplicate description thereof will be omitted.

First Embodiment

A description will now be given of a first embodiment according to the present invention. This specification sets an X direction to a moving direction in which the following vibrator and friction member move relative to each other, and a Z direction to a pressing direction for pressing the vibrator against the friction member. In the Z direction, +Z direction is set to a direction from the following vibrator to the friction member, and −Z direction is set to a direction from the friction member to the vibrator. A Y direction is set to an orthogonal direction orthogonal to each of the X direction and the Z direction.

Referring now toFIGS. 1A to 1C, a description will be given of a configuration of an ultrasonic motor150as a vibration type motor according to this embodiment and a lens apparatus160including the ultrasonic motor150. The ultrasonic motor150constitutes part of a lens driving unit that drives a lens120in the lens apparatus160.FIGS. 1A to 1Cillustrate the configuration of the ultrasonic motor150and the lens apparatus160including the ultrasonic motor150.FIG. 1Ais a front view of the lens apparatus160,FIG. 1Bis a front view of the ultrasonic motor150enlarging a region180inFIG. 1A, andFIG. 1Cis a sectional view taken along a line A-A inFIG. 1B.

Each of a vibrator (first vibrator)100X and a vibrator (second vibrator)100Y includes a vibration plate101having two protrusions101aand a piezoelectric element102that vibrates at a high frequency. The piezoelectric element102vibrates at a high frequency (ultrasonically) when an unillustrated power supply applies the voltage. The piezoelectric element102is fixed onto the vibration plate101by the adhesion or other means, and the high frequency vibration of the piezoelectric element102excites the high frequency vibrations in the entire corresponding vibrators100X and100Y. Each of a friction member (first friction member)103X and a friction member (second friction member)103Y contact a corresponding one of the vibrators100X and100Y and is fixed onto a base member108by a screw etc. The vibrators100X and100Y are fixed onto a holder105by the adhesion and other means. The holder105is fixed onto a fixing member112by the adhesion or other means via a coupling plate113. However, this embodiment is not limited to fixing these members by screws or adhesions, but is applicable to a fixing method using other means.

A pressure member104presses each of the vibrators100X and100Y against the corresponding one of the friction members103X and103Y and presses the vibrator100through an upper pressure plate109, a lower pressure plate111, and an elastic plate110. The pressure member104connects the upper pressure plate109and the fixed side plate (fixed plate)114at two locations and provides a pressure so as to press the vibrators100X and100Y against the friction members103X and103Y.

According to this embodiment, the ultrasonic motor150includes two vibrators100X and100Y and two friction members103X and103Y contacting them. The vibrators100X and100Y are spaced from each other and arranged in parallel in a direction (Y direction) orthogonal to the pressure direction (Z direction). Similarly, the friction members103X and103Y are also arranged in parallel in the direction (Y direction) orthogonal to the pressure direction (Z direction). Reference numerals for two parallel pairs arranged in the Y direction as the same members may be omitted in each drawing for simpler views.

The upper pressure plate109is engaged with the fixing member112about an engagement portion112aof the fixing member112as a rotation center and contacts a convex portion on the lower pressure plate111to transmit the pressure of the pressure member104to it. The lower pressure plate111is disposed across the tops of the vibrators100X and100Y. An elastic plate110is disposed between the lower pressure plate111and each of the piezoelectric elements102in the vibrators100X and100Y. The elastic plate110prevents the pressure part of the lower pressure plate111and the piezoelectric elements102from directly contacting each other, and protects the piezoelectric elements102from damage.

The fixed side plate114is fixed onto the fixing member112with unillustrated screws or the like. A movable side plate (guide plate)106is fixed onto the base member108with a screw116. However, the fixing method of these members is not limited to this example. Since the friction members103X and103Y are also fixed onto the base member108, the movable side plate106is integrated with the friction members103X and103Y. A fixed surface106bfixed by the screw116on the movable side plate106is lower to a position closer to the base member108than a surface106con which a movable side guide groove (first groove)106ais provided. Therefore, when the movable side plate106moves relative to the fixed side plate114, the screw116does not interfere with the fixed side plate114and the movable side plate106can be smaller in the moving direction (X direction). The base member108onto which the friction members103X and103Y and the movable side plate106are fixed is located on the vibrators100X and100Y side (+Z direction) of the friction members103X and103Y and the movable side plate106. The base member108is thus provided so as to overlap the vibrator100in the pressure direction (Z direction) and can be made smaller in the pressure direction (Z direction) than the base member108provided on the opposite side of the vibrators100X and100Y.

The fixed side plate114has two V-shaped fixed side guide grooves (second grooves)114a.The movable side plate106also has two V-shaped movable side guide grooves106a.The movable side guide groove106aon the movable side plate106and the fixed side guide groove114aon the fixed side plate114are opposed to each other. A spherical guide member (first guide member)107X and a spherical guide member (second guide member)107Y guide the relative movement between the vibrators100X and100Y and the friction members103X and103Y. The guide members107X and107Y are engaged with and held by the movable side guide groove106aand the fixed side guide groove114a.In other words, the movable side plate106contacts the guide members107X and107Y. This configuration linearly guides the movable side plate106and the fixed side plate114in the X direction, as the spherical guide members107X and107Y roll on the V-shaped movable side guide groove106aand fixed side guide groove114a.

This embodiment sets the friction members103X and103Y to movable parts and the vibrators100X and100Y to fixed parts in the relative movements between the vibrators100X and100Y and the friction members103X and103Y. The friction members103X and103Y are integrated with the movable side plate106, and the vibrator100is integrated with the fixed side plate114. Hence, the vibrators100X and100Y and the friction members103X and103Y are linearly guided by the guide members107X and107Y in the X direction as the following moving direction. The movable side plate106is provided between the two friction members103X and103Y. In addition, the movable side plate106is provided so as to overlap at least part of each of the friction members103X and103Y when viewed from the direction (Y direction) orthogonal to the pressure direction (Z direction). Thus, the configuration of this embodiment can be smaller than the configuration in which the movable side plate106and the friction members103X and103Y overlap each other in the pressure direction (Z direction).

The base member108is connected to the lens holder121tightly in the moving direction (X direction). The lens holder121holds the lens120, is engaged with a first guide bar122, and thereby is linearly guided so as to be rotatable around the moving direction (X direction). The first guide bar122is fixed onto an unillustrated member as labelled “fixed” inFIGS. 1A and 1B. The lens holder121is engaged with a second guide bar123as a rotation restricting member of the lens holder121. The second guide bar123is also fixed onto an unillustrated member as labelled “fixed” inFIGS. 1A and 1B. Thereby, the lens holder121is restricted from rotating, and is linearly guided without rotating in the moving direction (X direction). According to this embodiment, the lens apparatus160includes the ultrasonic motor150, the lens120, the lens holder121, the first guide bar122, and the second guide bar123.

As described above, the piezoelectric element102excites the high-frequency vibration in the vibrators100X and100Y. Thereby, an elliptical motion is generated on the projections101aof the vibration plate101. The vibrators100X and100Y are pressed against and brought into contact with the friction members103X and103Y by the pressure member104. Thus, the elliptical motions of the vibrators100X and100Y generates the frictions between the vibrators100X and100Y and the friction members103X and103Y, so that the vibrators100X and100Y and the friction members103X and103Y move relative to each other in the moving direction (X direction). The friction members103X and103Y move in the moving direction (X direction) relative to the vibrators100X and100Y integrated to the fixing member112. Thus, the base member108onto which the friction members103X and103Y are fixed, the lens holder121, and the lens120move in the moving direction (X direction). In other words, the lens120can be moved in the X direction by the relative movements between the vibrators100X and100Y and the friction members103X and103Y as the voltage is applied to the piezoelectric element102.

Referring now toFIGS. 2A to 2C, a description will be given of positions of the guide members107X and107Y.FIGS. 2A to 2Care explanatory views of the positions of the guide members107X and107Y.FIGS. 2A and 2Bare top views of principal parts of the ultrasonic motor150, andFIG. 2Cis a front view corresponding toFIG. 19.FIGS. 2A and 2Bomit the pressure member104, the holding member105, the upper pressure plate109, the elastic plate110, the lower pressure plate111, and the coupling plate113.FIG. 2Aillustrates the movable part, such as the friction members103X and103Y, located at the center in the moving range, andFIG. 2Billustrates the movable part located in the moving range at the end in the −X direction.

The vibrators100X and100Y are pressed against the friction members103X and103Y by the pressure member104so that the protrusions101aof the vibrators100X and100Y compressively contact the friction members103X and103Y. Thus, a pressure (resultant force) Pa1applied to the two protrusions101ais applied to each of the friction members103X and103Y. The ultrasonic motor150includes the two vibrators100X and100Y and the two friction members103X and103Y. The two vibrators100X and100Y are arranged in the direction (Y direction) approximately orthogonal to the moving direction (X direction) in which the vibrators100X and100Y and the friction members103X and103Y move relative to each other. The two friction members103X and103Y are also arranged in the direction (Y direction) approximately orthogonal to the moving direction (X direction). A pressure Pa1is applied to each of the two friction members103X and103Y, and the two friction members103X and103Y and the movable side plate106are integrated with the base member108. Thus, a resultant force Pb1of the two applied pressures Pa1is applied to the friction members103X and103Y, the movable side plate106, and the base member108.

The guide members107X and107Y are aligned with the moving direction (X direction) between the vibrators100X and100Y, and the position (pressure center) to which the resultant force Pb1of the applied pressures Pa1is applied is located inside a range C that encloses the guide members107X and107Y. In other words, the resultant force Pb1of the pressures Pa1applied to the vibrators100X and100Y by the pressure member104is given to the inside of the guide members107X and107Y within the following relative movement range LS1between the vibrators100X and100Y and the friction members103X and130Y. In other words, the resultant force Pb1is given between the guide members107X and107Y in the X direction. Thereby, the pressures Pa1applied to the vibrators100X and100Y can prevent the movable side plate106from lifting and stably press it.

This embodiment sets a distance D1in the orthogonal direction (Y direction) between each of the guide members107X and107Y and the vibrator100X to be smaller than a distance D2in the orthogonal direction between each of the guide members107X and107Y and the vibrator100Y (Y direction). The configuration according to this embodiment provides the base member108fixed to the friction members103X and103Y with a moment about the moving direction (X direction) due to the pressure Pa1of the pressure member104. However, the distances D1and D2are equal to each other and thus the moments due to the pressures Pa1applied to the vibrators100X and100Y are well balanced, so that no unnecessary moment is generated in the base member108.

Referring now toFIGS. 3A and 3B, a description will be given of each angle and length of the movable side guide groove106aand the fixed side guide groove114a.FIGS. 3A and 3Bare explanatory views of the angles and lengths of the movable side guide groove106aand the fixed side guide groove114a.FIG. 3Ais an enlarged view of a range D inFIG. 2C, andFIG. 3Bis an enlarged view of a range E inFIG. 3A.FIG. 3Aomits the guide members107X and107Y in order to illustrate the angles of the movable side guide groove106aand the fixed side guide groove114a.θ1and θ2are V-shaped angles in the movable side guide groove106aand the fixed side guide groove114a,respectively. As described above, as the movable side plate106and the fixed side plate114move relative to each other, the spherical guide members107X and107Y roll over the movable side guide groove106aand the fixed side guide groove114a.At this time, the movable side plate106and the fixed side plate114move relative to the guide members107X and107Y, respectively, and the relative movement amount (rolling amount) is determined based on the angles of the movable side guide groove106aand the fixed side guide groove114a.

Assume that RM1is a rolling radius when the guide members107X and107Y roll over the movable side guide groove106a,and RS1is a rolling radius when the guide members107X and107Y roll on the fixed side guide groove114a. Then, the rolling amounts of the movable side plate106and the fixed side plate114when the guide members107X and107Y roll and make one turn become 2πRM1and 2πRS1. Assume that LS1is a relative movement range of the ultrasonic motor150and n is the number of revolutions at which the guide members107X and107Y roll when the base member108moves over the range LS1. In addition, LRMand LRSare lengths of the guide members107X and107Y rolling on the movable side guide groove106and the fixed side guide groove114, respectively. Then, the range LS1is calculated as LS1=LRM+LRS, the rolling lengths LRMand LRSare n×2πRM1and n×2πRS1, and these lengths are required for the movable side guide groove106aand the fixed side guide groove114a.The rolling radii RM1and RS1are expressed by the following expressions (1A) and (1B), respectively, using the angles θ1and θ2of the V-shaped groove.
RM1=r×sin θ1   (1A)
RS1=r×sin θ2   (1B)

In the expressions (1A) and (1B), r is a radius of each of the guide members107X and107Y. Thus, larger angles θ1and θ2of the V-shaped grooves provide the larger rolling radii RM1and RS1and the longer necessary length of each guide groove. This embodiment sets the angle θ1of the movable side guide groove106ain the movable side plate106to be smaller than the angle θ2of the fixed side guide groove114ain the fixed side plate114. This configuration can make shorter the movable side guide groove106aand to configure the movable side guide groove106awithout increasing its size in the relative movement direction of the movable side plate106.

Referring now toFIGS. 4A to 4C, a description will be given of a relationship between the range LS1and the length of the movable side guide groove106a.FIGS. 4A to 4Care explanatory views of the relationship between the range LS1and the length of the movable side guide groove106a.FIGS. 4A to 4Care top views and illustrate only the movable side guide groove106a,the guide members107X and107Y, and the resultant force (pressure center) Pb1for simpler views.FIG. 4Aillustrates the movable part, such as the friction members103X and103Y, located at the center in the range LS1.FIGS. 4B and 4Cillustrate the positional relationship among the movable side guide groove106a,the guide members107X and107Y and the resultant force (pressure center) Pb1when the movable part is located at the end in the −X direction and the end in the +X direction in the range LS1.

The friction members103X and103Y the base member108, and the movable side plate106are moved in the X direction relative to the fixed pressure member104, upper pressing plate109, and the like by the relative movement between the vibrators100X and100Y and the friction members103X and103Y. Thus, the position of the resultant force (pressure center) Pb1is maintained despite the relative movement between the vibrators100X and100Y and the friction members103X and103Y, and the movable side guide groove106amoves in the X direction. In response, the guide members107X and107Y move in the X direction while rolling on the movable side guide groove106a.At this time, as described above, the resultant force (pressure center) Pb1is located inside the two guide members (rolling members)107X and107Y in the entire range of the range LS1and on the dotted line in each ofFIGS. 4A to 4C. Now assume that L1is an occupancy range of the movable side guide groove106a.Then, the occupancy range L1is calculated with a length LM1of the two movable side guide grooves106aand a distance LD1between the two movable side guide grooves106a,as expressed in the following expression (2).
L1=2×LM1+LD1(2)

The length LM1is determined according to the size of the range LS1as described above. The distance LD1is a minimum machinable distance to form, for example, two groove shapes. This embodiment provides two movable side guide grooves106aand two fixed side guide grooves114ato the two guide members107X and107Y, but is not limited to this example. For example, one movable side guide groove106aand one fixed side guide groove114amay be provided to the two guide members107.

Referring now toFIGS. 5A and 5B, a description will be given of an ultrasonic motor150aaccording to a variation of the present embodiment.FIGS. 5A and 5Bare explanatory views of the guide members107X and107Y, the movable side guide groove106a,and the fixed side guide groove114ain the ultrasonic motor150aaccording to the variation.FIG. 5Ais a top view corresponding toFIG. 2A, andFIG. 5Bis a front view corresponding toFIG. 1B.FIG. 5Aomits the vibrators100X and100Y, and illustrates the movable side plate106with a dotted line so as to illustrate the fixed side plate114and the fixed side guide groove114a.

The ultrasonic motor150ahas one movable guide groove106aand one fixed guide groove114a.The guide members107X and107Y are provided so as to be engaged with the movable side guide groove106aand the fixed side guide groove114a,respectively. The holding plate117is a plate-shaped member with a hole located between the movable side guide groove106aand the fixed side guide groove114a.The guide members107X and107Y are provided in the hole portion117ain the holding plate117. Thereby, the configuration with only one movable side guide groove106aand only one fixed side guide groove114acan keep constant the distance between the guide members107X and107Y. One movable side guide groove106acan eliminate the interval LD1between the two movable side guide grooves106a,and make narrow the occupancy range L1of the movable side guide groove106a.

Referring now toFIGS. 8A, 8B, and 9A to 9C, a description will be given of an ultrasonic motor950according to a comparative example.FIGS. 8A and 8Bare explanatory views of the positions of the guide members907X,907Y, and907Z in the ultrasonic motor950.FIGS. 8A and 8Bare top views corresponding toFIGS. 2A and 2B.FIGS. 9A to 9Care explanatory diagrams of the relationship between the range (relative movement range) LS9of the ultrasonic motor950and the length of the movable side guide groove906a.FIGS. 9A to 9Care top views corresponding toFIGS. 4A to 4C.

The ultrasonic motor950has three guide members907X,907Y, and907Z. In addition, the ultrasonic motor950has two movable side guide grooves906a1corresponding to the guide members907X and907Y, and one movable side guide groove906a2corresponding to the guide member907Z. The ultrasonic motor950has three fixed side guide grooves914acorresponding to the two movable side guide grooves906a1and one movable side guide groove906a2.

Two movable side guide grooves906a1are arranged in parallel in the moving direction (X direction), and one movable side guide groove906a2is provided on the opposite side of the two movable side guide grooves906a1with respect to the vibrators900X and900Y. In order to stably press the vibrators900X and900Y against the friction members903X and903Y, the movable side guide grooves906a1and906a2are provided so that the resultant force (pressure center) Pb9is located inside a triangular range F made by connecting the guide members907X,907Y, and907Z in the entire range LS9. This comparative example separates the resultant force (pressure center) Pb9and the two movable side guide grooves906a1by a distance DB9in the orthogonal direction (Y direction), and thus needs to separate the two movable side guide grooves906a1by a distance LD9. Therefore, the occupancy range L9of the movable side guide groove906a1(expressed by L9=2×LM9+LD9using the length LM9of the two movable side guide grooves906a1and the distance LD9between the two provable side guide grooves906a1).

A description will now be given of the effects of this embodiment. In comparison with the comparative example, this embodiment provides the movable side guide groove106abetween the two vibrators100X and100Y, and a distance between the movable side guide groove106aand the resultant force (pressure center) Pb1in the orthogonal direction (Y direction) becomes zero. Therefore, it is necessary to separate them by the distance LD1between the two movable side guide grooves906a.Alternatively, as described above, the interval LD1can be set to zero when the two movable side guide grooves106ais reduced to one. Thereby, the occupancy range L1of the movable side guide groove106acan be made smaller than that of the comparative example. In other words, this embodiment can reduce the occupation range of the guide groove in the moving direction and realizes a miniaturization in the moving direction.

This embodiment discusses the configuration in which the friction members103X and103Y move in the X direction relative to the vibrators100X and100Y fixed to the fixing member112, but is not limited to this embodiment. For example, the friction members103X and103Y may be fixed onto the fixing member112, and the vibrators100X and100Y may be relatively movable in the X direction. A wide moving range can reduce the size in the moving direction with the configuration in which the vibrators100X and100Y move. This embodiment also discusses the configuration in which the vibrators100X and100Y are respectively pressed against the two friction members103X and103Y but the vibrators100X and100Y may be pressed against a single friction member. One friction member can reduce the cost.

Second Embodiment

Next follows a description of a second embodiment according to the present invention. The first embodiment has discussed the configuration in which the two guide members are located between the two vibrators. On the other hand, this embodiment is different from the first embodiment in that this embodiment provides three guide members with two guide members located between two vibrators. A description of the element common to the first embodiment will be omitted.

FIGS. 6A to 6Care explanatory views of the positions of the guide members207X,207Y, and207Z according to this embodiment.FIGS. 6A and 6Bare top views of an ultrasonic motor250,FIG. 6Cis its front view, and these figures correspond toFIGS. 2A to 2C.FIGS. 7A to 7Care explanatory views of the relationship between a range (relative movement range) LS2of the ultrasonic motor250and the length of the movable side guide groove906a.FIGS. 7A to 7Care top views corresponding toFIGS. 4A to 4C.

The ultrasonic motor250according to this embodiment has the vibrators200X and200Y, the friction members203X and203Y, a movable side plate206, a fixed side plate214, and a base member208. The ultrasonic motor250has three guide members207X,207Y and207Z while the two guide members207X and207Y are located between the vibrators200X and200Y. As illustrated inFIG. 6C, a distance D1in the Y direction between each of the guide members207X and207Y and the vibrator200X is larger than a distance D2in the Y direction between each of the guide members207X and207Y and the vibrator200Y (D1>D2). As illustrated inFIGS. 6A and 6B, the guide members207X,207Y and207Z are arranged such that the resultant force (pressurizing center) Pb2is located inside a triangular area G made by connecting the guide members207X,207Y and207Z, in the entire drive range LS2.

In the comparative example illustrated inFIGS. 9A to 9C, the resultant force (pressure center) Pb9and the two movable side guide grooves906a1are separated by the distance DB9in the orthogonal direction (V direction), and the two movable side guide grooves906a1need to be separated by the distance LD9. On the other hand, this embodiment provides the guide grooves207X and207Y between the vibrators200X and200Y. Therefore, the distance DB2between the resultant force (pressure center) Pb2and each of the two movable side guide grooves206a1can be made smaller, and the distance LD2between the two movable side guide grooves206a1can be made smaller. Hence, the occupancy range L2of the movable side guide groove206a1can be made narrower (which is expressed by L2=2×LM2+LD2using the length LM2of the two movable side guide grooves206a1and the distance LD2between the two movable side guide grooves206a1). In other words, the occupancy range of the guide groove in the moving direction can be made smaller for the miniaturization in the moving direction. This embodiment provides the three guide members207X,207Y, and207Z, receives the pressure of the pressure member204, and has a meritorious effect of the stable orientation of the base member208.

Third Embodiment

Referring now toFIG. 10, a description will be given of an imaging apparatus according to a third embodiment of the present invention.FIG. 10illustrates a configuration (sectional view) of an imaging device3. The imaging device3includes the ultrasonic motor, such as the ultrasonic motor150of each of the above embodiments. The imaging device3includes a camera body (imaging apparatus body)32and a lens barrel (lens apparatus)31attachable to and detachable from the camera body32. However, this embodiment is not limited to this example, and is applicable to an imaging apparatus in which a camera body and a lens barrel are integrated with each other.

The camera body32includes an image sensor32a.The image sensor32aincludes a CMOS sensor or a CCD sensor, photoelectrically converts an optical image (object image) formed by the imaging optical system (lenses G1, G2, and G3) in the lens barrel31, and outputs image data. A mount321on the camera body32has a bayonet portion used to attach the lens barrel31to the camera body32.

The lens barrel31has a fixed barrel311that contacts a flange portion in the mount321. The fixed barrel311and the mount321are fixed by an illustrated screw. A front barrel312for holding the lens G1and a rear barrel313for holding the lens G3are fixed onto the fixed barrel311. The lens barrel31includes a lens holding frame314that holds the lens G2. The lens holding frame314is linearly movably held by a first guide bar122. held by the front barrel312and the rear barrel313. The ultrasonic motor150is fixed onto the rear barrel313by unillustrated screws or the like. This configuration transmits the driving force of the ultrasonic motor150to the lens holder121when the vibrator in the ultrasonic motor150vibrates. Then, the lens holder121linearly moves in a direction along an optical axis C while guided by the first guide bar122.

Each embodiment spaces the first and second vibrators (vibrators100X and100Y) in a direction (which is preferably a direction (Y direction) orthogonal to the relative movement direction) different from the relative movement direction (X direction) between the first and second vibrators and the friction members103X and103Y. The first and second guide members (guide members107X and107Y) are provided between the first and second vibrators in the direction different from the relative movement direction (X direction). The ultrasonic motor according to each embodiment can reduce the occupancy range of the guide groove and thereby size in the moving direction. Therefore, each embodiment can provide a compact ultrasonic motor, lens apparatus, and imaging apparatus.

The third embodiment drives the imaging optical system (lens) by the vibration type motor, but may drive a component other than the imaging optical system (lens) in the imaging apparatus. For example, the image sensor is set to a target to be driven and the above vibration type motor may be used to drive the image sensor in a direction orthogonal to the optical axis in the imaging optical system. The electronic apparatus to which the present invention is applicable is not limited to the imaging apparatus, but the above vibration type motor may be used to drive a component as the target to be driven in an electronic apparatus other than the imaging apparatus.

For example, the ultrasonic motor according to each embodiment is not limited to the lens apparatus, and is applicable to another electronic apparatus that is required to be small and lightweight, and to have a wide driving speed range.

This application claims the benefit of Japanese Patent Application No. 2017-226466, filed on Nov. 27, 2017, which is hereby incorporated by reference herein in its entirety.