JP2014138438A - Pressing mechanism for standing wave type piezoelectric vibration motor, lens driving device and lens barrel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pressing mechanism for a standing wave type piezoelectric vibration motor which can press a vibrator to a driver side in a stable state by reducing the disturbance of vibration of the vibrator, and a lens driving device using a standing wave type piezoelectric vibration motor having the pressing mechanism.SOLUTION: A pressing mechanism for a standing wave type piezoelectric vibration motor is provided on the one end side of a piezoelectric vibration motor body, and brings a vibration output terminal on the other end side into contact with a driven object with energization. The pressing mechanism uses an energizing member provided with a contact surface which comes into contact with the surface on the one end side of the piezoelectric vibration motor body to press it, and has lubricant slide resistance reduction means which makes the contact surface of the energizing member retain a lubricating agent in order to reduce slide resistance generated between the vibrating piezoelectric vibration motor body and the energizing member.

Description

  The present invention relates to a pressing mechanism for a standing wave piezo vibration motor that is disposed on one end side of a piezo vibration motor main body that is a vibrating body, and that urges and contacts a vibration output terminal that is provided on the other end side to a driven object. The present invention relates to a lens driving device and a lens barrel using a standing wave type piezoelectric vibration motor having a mechanism.

  Conventionally, there has been a piezoelectric vibration motor using a reverse piezoelectric effect as a drive source for various devices including a movable mechanism. A piezo vibration motor refers to a motor that vibrates a piezo vibration motor body made of a piezo element and extracts the vibration as a driving force through a frictional force. Piezo vibration motors can achieve low speed and high torque, have excellent quietness, and are suitable for miniaturization and weight reduction. For example, precision auto-focus function, zoom function, scanning electron microscope, etc. It is suitably used as a drive source for a movable mechanism that requires positioning.

  Incidentally, there are two types of piezoelectric vibration motors, standing wave type and traveling wave type. Here, the standing wave type piezo vibration motor mainly has a rectangular shape, and vibrates a piezo vibration motor main body composed of piezo elements, and generates a rotational motion such as an ellipse at a vibration output terminal at one end thereof. The vibration output terminal is urged into contact with the driven object, and the driven object is driven by the frictional force between them. On the other hand, a traveling wave type piezoelectric vibration motor mainly has an annular shape, vibrates an elastic body to which a piezoelectric element is attached, and generates a traveling wave that forms elliptical vibration on the elastic body surface. Is urged into contact with the driven object, and the driven object is driven by the frictional force between them. Therefore, in order to reduce the size of the piezoelectric vibration motor, it is preferable to employ a standing wave type piezoelectric vibration motor rather than a traveling wave type piezoelectric vibration motor due to its shape and structure.

  By the way, in order to transmit the driving force to the driven object side using the standing wave type piezo vibration motor, it is necessary to urge the vibration output terminal of the piezo vibration motor main body against the driven object. A pressing mechanism for pressing the piezoelectric vibration motor main body toward the driven object side is provided. This pressing mechanism is generated by the vibration output terminal by pressing the vibration output terminal against the driven object by pressing from the side opposite to the side where the vibration output terminal is provided in the piezoelectric vibration motor main body. It is provided in order to reliably transmit a rotational motion such as an ellipse to the driven object.

  For example, Patent Document 1 relates to a vibration actuator used in various electronic devices, and more specifically, discloses an invention related to a standing wave type ultrasonic actuator using an electromechanical transducer. Here, in the ultrasonic actuator disclosed in Patent Document 1, the drive element causes an elliptical motion by synthesizing the bending vibration and the stretching vibration of the piezoelectric element, and the movable body supported by the drive element is operated by the elliptical motion. It is used for.

  In FIG. 1 and the like of Patent Document 1, the piezo element 10 is supported by the support portions 6A, 6B, 7A, 7B, and 9A of the supports 6, 7, and 9 provided on the mounted body 1, and the piezo element. The structure which supports 10 from the back surface via the support part 9A and presses the drive element 2 to the movable body 3 is shown. Here, in the ultrasonic actuator according to Patent Document 1, the pressing mechanism for pressing the piezo element 10 toward the movable body 3 side is provided with the support portion 9A for pressing the piezo element 10 toward the movable body 3 side as an elastomer. Further, the piezoelectric element 10 is brought into surface contact as an elastic body such as silicone rubber or a leaf spring. The ultrasonic actuator according to Patent Document 1 employs such a pressing mechanism to press the piezo element 10 toward the movable body 3, thereby reducing the inhibition of elongation vibration (stretching vibration) of the piezo element 10. To get.

Japanese Patent No. 4035156

  However, in the ultrasonic actuator disclosed in Patent Document 1, in the pressing mechanism for pressing the piezo element toward the movable body, the direction in which the support section is pressed by the movable body as the pressing force of the support section on the piezo element increases. The stretchability in the substantially parallel direction is lost, and the effect of reducing the obstruction vibration (stretching vibration) of the piezoelectric element cannot be sufficiently obtained, so that the driving efficiency of the ultrasonic actuator is lowered. The piezo element vibrates not only at the part that is in pressure contact with the movable body but also at the part that is pressed toward the movable body, and the support part is crushed and the hardness is reduced as the pressing force of the support part against the piezo element increases. As a result, the behavior of the piezo element becomes nonlinear, which is not preferable.

  Further, in the ultrasonic actuator disclosed in Patent Document 1, when the piezoelectric element vibrates, the contact state between the support unit that presses the piezoelectric element toward the movable body and the piezoelectric element is easily affected by the vibration. Therefore, when the mechanism for pressing the piezo element against the movable body in the ultrasonic actuator disclosed in Patent Document 1 is used in a standing wave type piezo vibration motor for moving a lens provided in the lens driving device, the movable body is restricted due to the restriction of the installation location. The pressing mechanism cannot be arranged on the substantially same straight line as the contact portion between the driving element and the driving element, and the pressing force by the pressing mechanism tends to become unstable. In addition, since a piezoelectric element used as a vibrating body in an ultrasonic actuator has hysteresis, the positional relationship between the pressing mechanism assumed in a stationary state and the piezoelectric element may slightly shift. As a result, the pressing force acting on the piezo element from the pressing mechanism is dispersed, so that the pressing cannot be performed in an optimum state, resulting in a problem that the driving efficiency is lowered.

  The present invention solves the above-described problems, and when the vibrating body in the standing wave piezo vibration motor is pressed against the driven object side, the obstruction of the vibration of the vibrating body is reduced, and the It is an object of the present invention to provide a pressing mechanism capable of pressing the vibrating body toward the driving body in a stable state, a lens driving device using the standing wave piezo vibration motor provided with the pressing mechanism, and a lens barrel. .

  Accordingly, as a result of intensive studies, the present inventors have achieved the above problem by employing the following pressing mechanism for a standing wave type piezoelectric vibration motor, a lens driving device, and a lens barrel.

Standing wave type piezoelectric vibration motor pressing mechanism according to the present invention: The standing wave type piezoelectric vibration motor pressing mechanism according to the present invention is arranged on one end side of the piezoelectric vibration motor main body, and is a vibration output terminal on the other end side. Is a pressing mechanism for a standing wave type piezo vibration motor that urges and contacts the driven object, and the pressing mechanism has a contact surface that can be pressed in contact with a surface on one end side of the piezo vibration motor main body. Lubricity that uses a biasing member provided and holds a lubricant on the contact surface of the biasing member in order to reduce sliding resistance generated between the vibrating piezoelectric vibration motor main body and the biasing member. A sliding resistance reduction means is provided.

  In the pressing mechanism for a standing wave piezo vibration motor according to the present invention, the lubricous sliding mitigation means has a groove shape, an opening shape, and an unevenness on a contact surface of an urging member disposed on one end side of the piezo vibration motor main body. It is preferable that any one of the shapes is provided to hold the lubricant.

  In the standing wave type piezoelectric vibration motor pressing mechanism according to the present invention, the lubricant is preferably an oil-based lubricant.

  In the pressing mechanism for a standing wave piezo vibration motor according to the present invention, the contact surface of the urging member disposed on one end side of the piezo vibration motor main body has a vibration output terminal on the other end side attached to the driven object. It is preferable to arrange so as to be substantially perpendicular to the urging shaft when the urging contact is made.

Lens drive mechanism according to the present invention: The lens drive mechanism according to the present invention is a lens drive device of an imaging apparatus, and is a standing wave type piezo provided with the above-described pressing mechanism as a drive source for moving the lens in the optical axis direction. A vibration motor is used.

Lens barrel according to the present invention: The lens barrel according to the present invention is characterized by using the lens driving device described above.

  The pressing mechanism for a standing wave piezo vibration motor according to the present invention is an urging member having the above-described characteristics on a surface of one end side of a piezo vibration motor main body that is a vibrating body in a standing wave piezo vibration motor. By arranging this, it is possible to maintain an appropriate vibration state without inhibiting the vibration of the piezo vibration motor main body. As a result, the driving unevenness of the standing wave type piezoelectric vibration motor is reduced, and the driving efficiency can be optimized. Further, according to the pressing mechanism for a standing wave piezo vibration motor according to the present invention, it is possible to reduce the size and weight of the lens driving device and the lens barrel using the piezo vibration motor provided with the mechanism.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing an embodiment of a standing wave type piezoelectric vibration motor pressing mechanism according to the present invention. It is the perspective view which showed 1st embodiment of the biasing member of this invention. It is the perspective view which showed the biasing member of the form different from the biasing member shown in FIG. It is sectional drawing which showed one Embodiment of the standing wave type piezoelectric vibration motor provided with the press mechanism containing the biasing member shown in FIG. It is the perspective view which showed 3rd embodiment of the biasing member of this invention. It is the perspective view which showed 4th embodiment of the biasing member of this invention. It is the perspective view which showed 5th embodiment of the biasing member of this invention. It is the perspective view which showed 6th embodiment of the biasing member of this invention. It is a principal part schematic sectional drawing of the imaging device provided with the lens drive device which concerns on one embodiment of this invention.

  Hereinafter, preferred embodiments of a pressing mechanism for a standing wave piezo vibration motor, a lens driving device, and a lens barrel according to the present invention will be described with reference to the drawings.

  FIG. 1 is a perspective view showing an embodiment of a pressing mechanism for a standing wave piezo vibration motor according to the present invention. FIG. 2 is a perspective view showing the first embodiment of the urging member of the present invention.

Standing wave type piezoelectric vibration motor pressing mechanism 10 according to the present invention: The standing wave type piezoelectric vibration motor 1 pressing mechanism 10 according to the present invention is disposed on one end side of the piezoelectric vibration motor 1 main body and on the other end side. The present invention relates to a pressing mechanism 10 for a standing wave piezo vibration motor 1 that biases and contacts a vibration output terminal 3 with a driven object (see reference numeral 20 in FIG. 8). The pressing mechanism 10 uses a biasing member 11 having a contact surface 11a that can be pressed in contact with a surface on one end side of the piezoelectric vibration motor main body 2, and vibrates a piezoelectric vibration motor main body. In order to reduce the sliding resistance generated between the urging member 11 and the urging member 11, a lubricating sliding resistance reducing means for holding the lubricant on the contact surface 11a of the urging member 11 is provided.

  As shown in FIG. 1, a standing wave type piezoelectric vibration motor 1 of the present invention includes a piezoelectric vibration motor main body 2 having a substantially rectangular parallelepiped shape including a piezoelectric element (not shown) as a vibrating body. As shown in FIG. 1, the piezo vibration motor main body 2 has a projecting vibration output terminal 3 on one end side thereof. In the standing wave type piezo vibration motor 1 using a piezo element, the shape of the piezo element, the place where the voltage is applied, the amount and period of the applied voltage, etc., so that the vibration output terminal 3 performs a predetermined regular motion. Is adjusted to generate vibration in the piezo element. The vibration output terminal 3 is disposed in contact with the driven object, so that the vibration of the piezo vibration motor main body 2 is transmitted to the driven object.

  The piezoelectric element in the standing wave type piezoelectric vibration motor 1 of the present invention includes a plurality of stacked piezoelectric bodies (not shown) and internal electrodes (not shown) sandwiched between the piezoelectric bodies. The internal electrodes are alternately stacked. Then, by applying an AC voltage whose phase is shifted to each internal electrode of the piezo element, the piezo vibration motor body 2 is excited simultaneously with vibrations of the stretching vibration mode and the bending vibration mode, and the vibration output terminal 3 is A rotational motion such as an ellipse is performed (see arrows shown in FIG. 1). The standing wave type piezo vibration motor 1 of the present invention takes out such a motion by the vibration output terminal 3 as a specific one-way motion by a frictional force. As described above, the standing wave type piezo vibration motor 1 of the present invention uses the vibration of the piezo element as a driving source, moves the driven output object in one direction by moving the vibration output terminal 3 in an elliptical manner, and the like. The operation of the object is converted into driving force and output.

  Further, the pressing mechanism 10 for the standing wave type piezoelectric vibration motor 1 according to the present invention is provided with a lubricant sliding resistance reducing means for holding the lubricant on the contact surface of the biasing member 11 with the piezoelectric vibration motor main body 2. Thus, the piezoelectric vibration motor main body 2 can be pressed and urged against the driven object without impeding the vibration of the piezoelectric vibration motor main body 2. Therefore, according to the pressing mechanism 10 for the standing wave type piezoelectric vibration motor 1 according to the present invention, the piezoelectric vibration motor main body 2 can be stably pressed against the driven object side, and the standing wave type piezoelectric vibration motor can be obtained. It is possible to efficiently transmit the elliptical motion or the like of one vibration output terminal 3 to the driven object. In addition, it is preferable for the biasing member 11 of the present invention to increase the hardness of the material because the coefficient of friction with the piezo vibration motor main body 2 can be further reduced.

  Further, the pressing mechanism 10 for the standing wave type piezoelectric vibration motor 1 according to the present invention is arranged so that the pressing direction of the urging member 11 is substantially parallel to the direction from the piezoelectric vibration motor main body 2 toward the driven object. It is desirable to do. By doing so, the vibration output terminal 3 of the piezo vibration motor main body 2 can be more stably pressed against the driven object side, and the driven object can be efficiently moved in one direction.

  As described above, the pressing mechanism 10 for the standing wave piezo vibration motor 1 according to the present invention presses the piezo vibration motor body 2 toward the driven object side, and the vibration output terminal 3 is driven. A structure in which the object is urged into contact is adopted. If a structure that presses the driven object toward the vibration output terminal 3 is used to transmit a rotational motion such as an ellipse generated by the vibration output terminal 3 to the driven object, It becomes difficult to reliably transmit the rotational movement of the vibration output terminal 3 to the driven object. Moreover, when the structure which presses the said to-be-driven target object to the said vibration output terminal 3 side is employ | adopted, there exists a possibility of causing the enlargement of a press mechanism, and is unpreferable.

  Further, in the pressing mechanism 10 for the standing wave type piezo vibration motor 1 according to the present invention, the lubricous sliding mitigation means has a groove on the contact surface 11a of the urging member 11 arranged on one end side of the piezo vibration motor 1 main body 2. It is preferable that any one of a shape, an opening shape, and a concavo-convex shape is provided and a lubricant is held therein.

  As described above, the urging member 11 constituting the pressing mechanism 10 for the standing wave type piezo vibration motor 1 according to the present invention is a contact surface with the standing wave type piezo vibration motor 1 as a lubricating sliding resistance reducing means. 11a is provided with a structure for holding a lubricant. For example, FIG. 2 shows that the groove 11c is provided on the contact surface 11a of the biasing member 11 of the present invention. As shown in FIG. 2, the urging member 11 of the present invention has a groove 11c formed in communication with the contact surface 11a of the urging member 11 so that the lubricant is held in the contact surface of the urging member 11. A lubricant is appropriately supplied onto 11a. As shown in FIG. 2, the biasing member 11 can be configured not to form a groove shape or the like on the outer peripheral edge so that the lubricant held by the groove-shaped portion 11 c does not easily leak.

  The urging member 11 is constantly pressed against the piezo vibration motor main body 2 side by the spring 12 locked to the spring locking portion 11b. The urging member 11 according to the present invention is provided with the shape as described above on the contact surface 11a, so that it is not in direct contact with the piezo vibration motor main body 2 but separated by a continuous oil film. The piezoelectric vibration motor main body 2 can be pressed and biased in a state where it is always interposed.

  Further, the urging member 11 of the present invention can appropriately supply the lubricant to the contact surface 11a by providing the contact surface 11a with any one of a groove shape, an opening shape, and an uneven shape. Become. For example, FIG. 3 shows a biasing member 11 ′ having a different form from the biasing member 11 shown in FIG. 2. As illustrated in FIG. 3, the biasing member 11 ′ of the present invention has the same contact surface 11 ′ as long as the basic structure is the same, such as the biasing member 11 shown in FIG. 2 and the spring locking portion 11 ′ b. Even if the shape of the groove 11′c provided in a is different from that of the biasing member 11 shown in FIG. 2, it is possible to appropriately supply the lubricant to the contact surface 11′a.

  In the urging member 11 of the present invention, the urging member 11 slides on a surface on one end side of the piezoelectric vibration motor main body 2 by injecting a lubricant into a groove-shaped portion 11c provided on the contact surface 11a. Sometimes, the lubricant is discharged from the groove-like shape portion 11c, and the lubricant is appropriately supplied between the urging member 11 and the piezoelectric vibration motor main body 2. Thereby, the urging member 11 of the present invention can always keep the direction in which the pressing force is applied to the piezo vibration motor main body 2, and the vibration output terminal 3 is always set to a predetermined object with respect to the driven object. Energizing contact can be made by pressing force.

  Further, the biasing member 11 of the present invention can reduce wear by appropriately supplying a lubricant to the contact surface with the piezo vibration motor main body 2, and can reduce the amount of heat generated by friction. Generation of noise at the contact portion with the piezoelectric vibration motor main body 2 can be suppressed. The urging member 11 of the present invention receives the load applied to the contact surface 11a with the fluid pressure of the lubricant when the lubricant is supplied to the contact surface 11a, and disperses the stress by expanding the pressure receiving area. In addition, the piezoelectric vibration motor main body 2 can be stably pressed and urged.

  The urging member 11 of the present invention can also have an internal structure that can smoothly supply the lubricant onto the contact surface 11a. For example, in FIG. 2, a groove-shaped portion 11 c is provided on the contact surface 11 a of the biasing member 11, and the lubricant is supplied so that the lubricant is appropriately supplied onto the contact surface 11 a of the biasing member 11. A shape in which the lubricant discharge path from the disposed position to the lubricant discharge port is formed by a stepped slope is shown. The urging member 11 according to the present invention includes the shape portion 11c as shown in FIG. 2 so that the lubricant can be discharged smoothly.

  FIG. 4 is a cross-sectional view showing an embodiment of a standing wave piezo vibration motor provided with a pressing mechanism including an urging member shown in FIG. As shown in FIG. 4, the piezo vibration motor main body 2 of the standing wave piezo vibration motor 1 is disposed at a position where the output terminal 3 on one side surface 2a abuts the driven object 20, and the other side. The pressing mechanism 10 is disposed in contact with the side surface 2b. The driven object 20 and the pressing mechanism 10 are each attached to the base member 30, and the piezoelectric vibration motor main body 2 serving as a vibrating body is accommodated and held in a vibrating body holder 31 attached to the base member 30. In FIG. 4, the pressing mechanism 10 includes a spring 25 that is locked by a bolt 25 in which one end of a spring 12 is locked by a spring locking portion 11 b and the other end of the spring 13 is screwed to a base member 30. Locked to the portion 25a. In this case, the pressing mechanism 10 rotates the bolt 25 to change the screwing position with the base member 30, whereby the spring 12 sandwiched between the spring locking portion 11 b and the spring locking portion 25 a. It becomes possible to adjust the force with which the biasing member 11 presses the piezo vibration motor main body 2.

  The lens driving mechanism in the present embodiment causes the output terminal 3 provided in the piezo vibration motor main body 2 to elliptically move by the vibration of the piezo vibration motor main body 2 to rotate the driven object 20 in one direction, thereby driving the driven A driving force is output from an output gear 23 attached to one end of the driving force output shaft portion 22 via a rolling member 21 that rotates following the object 20. Here, the output terminal 3 provided in the piezo vibration motor main body 2 is bonded to the piezo vibration motor main body 2 in a state where it cannot be easily separated. Further, the driving force output shaft portion 22 is rotatably supported by a driving force output shaft pressing ring 24 fixed to the base member 30. Further, as the rolling member 21, a member capable of smoothly rotating around the driving force output shaft portion 22 such as an angular bearing or a thrust bearing can be appropriately used.

  Incidentally, the opening pattern of the groove-like portion 11c provided on the contact surface 11a of the biasing member 11 of the present invention is not limited to the shape shown in FIGS. 2 and 3, but is a lattice shape, a circular shape, a linear shape, an arc shape. Alternatively, a zigzag shape, a spiral shape, or the like may be used. Further, the opening shape of the opening shape portion provided on the contact surface 11a of the biasing member 11 of the present invention with the piezo vibration motor main body 2 is a hole shape formed of a circular shape, an elliptical shape, a long hole shape, a polygonal shape, or the like. It may be. Moreover, the uneven | corrugated shaped part provided in the said contact surface 11a of the urging | biasing member 11 of this invention may be a thing in which the recessed part and the convex part were mixed regularly or irregularly in the porous form.

  For example, as shown in FIG. 5, the urging member 21 of the present invention may include a spring locking portion 21b and a lattice-shaped groove 21c formed on the contact surface 21a. Further, as shown in FIG. 6, the biasing member 31 of the present invention includes a spring locking portion 31 b and a concentric groove 31 c formed on the contact surface 31 a with the piezo vibration motor main body 2. I can do it. Further, as shown in FIG. 7, the biasing member 41 of the present invention includes a spring locking portion 41 b and a plurality of opening shapes 41 c are formed on the contact surface 41 a with the piezo vibration motor main body 2. I can do it. Further, as shown in FIG. 8, the biasing member 51 of the present invention includes a spring locking portion 51b, and a plurality of convex shapes 51c are formed on the contact surface 51a with the piezoelectric vibration motor main body 2. I can do it.

  Moreover, in the pressing mechanism 10 for the standing wave type piezoelectric vibration motor 1 according to the present invention, the lubricant is preferably an oil-based lubricant.

  The pressing mechanism 10 for the standing wave type piezoelectric vibration motor 1 according to the present invention uses an oil-based lubricant as a lubricant held by the biasing member 11 so that the piezoelectric vibration motor main body 2 and the biasing member 11 are in contact with each other. Lubricant can be appropriately supplied to the interface. Here, as the oil-based lubricant used in the pressing mechanism 10 of the present invention, it is desirable to use silicone grease, mineral oil grease, or the like. Here, the grease refers to a semi-solid lubricant obtained by mixing a liquid lubricant and a thickener, and can be suitably used for a portion requiring leakage resistance. Further, since the grease can maintain the lubricating performance for a long period of time even in a small amount, it is not necessary to replenish frequently. Incidentally, since the viscosity of the liquid lubricant is small, the oil cannot withstand the pressure on the contact surface and the fluid lubrication state cannot be maintained, so that it is not suitable for use in the pressing mechanism 10 of the present invention. However, if the viscosity of the semi-solid lubricant is too high, the frictional resistance increases, and friction loss occurs during the sliding operation. Therefore, the use of the standing wave type piezoelectric vibration motor 1 according to the present invention is used. It is preferable to adjust the viscosity according to the conditions.

  Note that the oil-based lubricant held by the biasing member 11 of the present invention has a high fluidity and may flow out of the biasing member 11, but may have a groove shape or the like provided on the contact surface of the biasing member 11. By disposing the fibrous substance in the portion 11c, the lubricant retention force is increased to prevent wasteful outflow of the lubricant, and the lubricant is appropriately supplied to the contact surface of the biasing member 11 by capillary action. It becomes possible. Here, the kind of the fibrous substance is not particularly limited, but, for example, felt, polypropylene fiber, or the like can be suitably used. Incidentally, the biasing member 11 of the present invention is provided with an opening portion 11d for supplying a lubricant on the side surface other than the contact surface 11a, and the lubricant is injected into the opening portion 11d, whereby the lubricant is loaded into the biasing member 11. Can be replenished. The urging member 11 of the present invention does not need to be replenished frequently by storing the lubricant therein.

  Further, in the pressing mechanism 10 for the standing wave type piezoelectric vibration motor 1 according to the present invention, the contact surface of the urging member 11 arranged on one end side of the piezoelectric vibration motor main body 2 has a vibration output terminal 3 on the other end side. It is preferable to arrange so as to be substantially perpendicular to the urging shaft when urging and contacting the driven object 20.

  The contact surface of the urging member 11 of the present invention is arranged so as to be substantially perpendicular to the urging shaft when the vibration output terminal 3 on the other end side is in urging contact with the driven object 20. The vibration output terminal 3 of the piezoelectric vibration motor main body 2 presses the driven object 20 with an appropriate force, so that the driving force output from the standing wave type piezoelectric vibration motor 1 is efficiently transmitted. Further, as described above, the standing wave piezo vibration motor 1 of the present invention converts the vibration of the piezo vibration motor main body 2 into a driving force and transmits it to the driven object 20, so that the vibration output terminal 3 It is desirable to press and contact the driven object 20 with a constant force. From the above, in the standing wave type piezoelectric vibration motor 1 according to the present invention, it is preferable that the driven object 20, the piezoelectric vibration motor main body 2, and the pressing mechanism 10 are arranged on a substantially straight line.

  Incidentally, the standing wave type piezo vibration motor 1 according to the present invention includes the vibration regulating member 4 that prevents the shaft deflection of the bias shaft of the vibration output terminal 3 on the outer periphery of the body portion of the piezo vibration motor main body 2. Appropriate vibrations can be generated in the piezo vibration motor main body 2, and the movement output to the vibration output terminal 3 is not uneven, so that drive efficiency and drive control ability can be improved.

  The standing wave type piezo vibration motor 1 of the present invention generates a vibration as an output unit by generating one natural vibration or two different natural vibrations at a predetermined frequency and timing in a piezo vibration motor body 2 as a vibrating body. At the output terminal 3, a rotational motion such as an ellipse or a reciprocating motion is generated. For example, a vibration output terminal is generated by causing the piezoelectric vibration motor body 2 to generate stretching vibration (longitudinal vibration) and bending vibration, matching the natural frequencies of the stretching vibration and bending vibration, and exciting them at predetermined timings. In 3, a rotational motion such as an ellipse occurs. The driven object 20 is brought into contact with the vibration output terminal 3, and the rotational movement of the vibration output terminal 3 is transmitted to the driven object 20 by the frictional force between the two, so that the driven object 20 rotates. To do.

  Therefore, the vibration of the piezo vibration motor main body 2 is hindered at a position where the vibration displacement of the piezo vibration motor main body 2 is minimized (a position corresponding to a common node when the stretching vibration and the bending vibration occur harmoniously). By arranging the vibration restricting member 4 as a member that supports the vibration, it is possible to effectively suppress the axial deflection of the urging shaft of the vibration output terminal 3 of the piezo vibration motor main body 2. As a result, the standing wave piezo vibration motor 1 of the present invention maintains the vibration of the piezo vibration motor main body 2 in an appropriate state, reduces drive unevenness due to fluctuations in the pressing force, and optimizes drive efficiency. Is possible. Incidentally, in FIG. 1, since the vibration regulating member 4 to be pressed against the piezo vibration motor main body 2 is disposed at a position corresponding to the node, the piezo vibration motor main body 2 is spaced at two locations on one side with an interval in the longitudinal direction. (A part separated from the center by about 30 to 40% of the element length).

  Further, the piezoelectric vibration motor main body 2 of the present invention is supported by the vibration restricting member 4 so that the resonance phenomenon generated by the vibration of the piezoelectric vibration motor main body 2 propagating to the surrounding parts does not occur, and an abnormal noise is generated. Generation can be prevented. The standing wave type piezo vibration motor 1 is characterized by quietness during operation in terms of driving principle, and therefore, a quiet design is desired for the driving mechanism. The vibration regulating member 4 can be supported more stably without hindering the vibration of the piezoelectric vibration motor 1 by using an elastomer, silicon rubber, a leaf spring, a coil spring, or the like. Moreover, although the vibration control member 4 is shown by the column shape in FIG. 1, this invention is not limited to this. For example, the vibration regulating member 4 can have a spherical shape or a truncated cone shape as an outer shape.

Lens driving device according to the present invention: A lens driving device 51 according to the present invention is a lens driving device of an imaging apparatus, and is provided with the pressing mechanism 10 as a driving source for moving the lens in the direction of the optical axis O. A wave type piezoelectric vibration motor 1 is used.

  FIG. 9 is a schematic cross-sectional view of a main part of an imaging device including a lens driving device according to an embodiment of the present invention. The lens driving device 51 according to the present invention uses the standing wave piezo vibration motor 1 provided with the above-described pressing mechanism 10 as means for moving the lens 57 in the optical axis O direction. For example, the piezo vibration motor 1 of the present invention connects the lens 57 as shown in FIG. 9 to the driven object 20 to which the vibration output terminal 3 of the piezo vibration motor main body 2 is pressed. It can act as a drive source that moves in the direction of the optical axis O. The driven object 20 is a movable member that is driven based on the motion transmitted from the vibration output terminal 3 of the piezo vibration motor main body 2, and has an outer shape that is cylindrical, and rotates about the driving force output shaft portion 22. Attached to the base member as possible. When the vibration output terminal 3 of the piezo vibration motor main body 2 is pressed against the driven object 20 and the vibration output terminal 3 makes a predetermined motion, the frictional force between the vibration output terminal 3 and the driven object 20 causes the object to be driven. The drive object 20 rotates.

  The lens driving device 51 according to the present invention can reduce the size of the entire lens driving device 50 by using the standing wave piezo vibration motor 1 provided with the pressing mechanism 10 described above, and can also achieve driving efficiency and driving. It is possible to realize a high-performance lens driving device with excellent control ability.

  Here, the lens driving mechanism of the lens driving device 51 according to the present invention will be briefly described with reference to FIG. 9, the lens driving mechanism of the present invention includes a fixed cylinder 52 fixed in the lens barrel 50, a cam cylinder 53 inserted through the outer periphery of the fixed cylinder 52, and the driving force output shaft portion 22. A focus gear ring 54 that meshes with the gear 22 provided on one end side and rotates about the optical axis O, and one end side is coupled to the focus gear ring 54 and the other end side is a convex provided on the outer periphery of the cam cylinder 53. And an arm member 56 coupled to the portion 55. A standing wave type piezoelectric vibration motor unit 51 is disposed in the vicinity of the outer peripheral surface from the imaging side of the fixed cylinder 52.

  As shown in FIG. 9, the lens driving mechanism of the present invention is arranged in a state where the focus lens 57 is held by the lens holding frame 58 in the fixed cylinder 52, and the convex portion 59 is provided on the lens holding frame 58. The cam roller 60 is inserted into the convex portion 59. The cam roller 60 passes through a straight cam groove hole (not shown) of the fixed cylinder 52 and a cam groove hole (not shown) of the cam cylinder 53 and is disposed between the fixed cylinder 52 and the cam cylinder 53. Fixed to the straight cylinder 61. Then, when the cam cylinder 53 rotates at a fixed position with respect to the direction of the optical axis O within the cam groove hole, the cam roller 60 moves along the straight cam groove hole. Along with the cam roller 60, it slides in the direction of the optical axis O.

  That is, the lens driving mechanism of the present invention shown in FIG. 9 is held via the cam roller 60 when the cam cylinder 53 is rotated by the rotation of the gear 22 fixed to one end side of the driving force output shaft portion 22. When the lens holding frame 58 slides in the direction of the optical axis O together with the rectilinear cylinder 61, the focus adjustment of the focus lens 57 is performed. Incidentally, in FIG. 9, the lenses denoted by reference numerals 62 and 63 are fixed lenses.

Lens barrel according to the present invention: The lens barrel 50 according to the present invention is characterized by using the lens driving device 51 described above.

  According to the lens driving device 51 described above, the lens barrel 50 according to the present invention can reduce the occupied area viewed from the optical axis direction, and can reduce the size and weight of the lens barrel. Further, by using the lens barrel 50 according to the present invention, the image pickup apparatus can be reduced in size and weight.

  Although the standing wave type piezoelectric vibration motor pressing mechanism according to the present invention has a simple structure, it can always maintain a good transmission of driving force to the driven object side of the piezoelectric vibration motor main body. I can do it. Therefore, the lens driving device according to the present invention uses the standing wave piezo vibration motor pressing mechanism according to the present invention, so that the driving efficiency is improved and the control at the time of lens movement can be performed with high accuracy. . In addition, the lens driving device according to the present invention includes such a piezo vibration motor with high driving efficiency, so that the power consumption can be suppressed. Moreover, the lens barrel according to the present invention can be reduced in size and weight by using this lens driving device. From the above, the piezo vibration motor pressing mechanism and the lens driving device according to the present invention are capable of providing an imaging device having good imaging quality, and are important mechanical elements in configuring the entire system in the industrial field. It can be suitably used for a certain positioning mechanism or the like.

DESCRIPTION OF SYMBOLS 1 Piezo-electric vibration motor 2 Piezo-electric vibration motor main body 3 Vibration output terminal 4 Vibration control member 10 Pressing mechanism 11 Energizing member 11a Contact surface 11b Spring locking part 11c Groove-shaped part 12 Spring

Claims (6)

A pressing mechanism for a standing wave piezo vibration motor, which is disposed on one end side of the piezo vibration motor main body and urges and contacts the vibration output terminal on the other end side to the driven object,
The pressing mechanism uses an urging member having a contact surface that can be pressed in contact with a surface on one end side of the piezoelectric vibration motor main body,
In addition, in order to reduce the sliding resistance generated between the vibrating piezo vibration motor main body and the biasing member, a lubricating sliding resistance reducing means for holding the lubricant on the contact surface of the biasing member is provided. A pressing mechanism for a standing wave piezo vibration motor. The lubrication sliding mitigation means is provided with a groove shape, an opening shape, or an uneven shape on a contact surface of an urging member disposed on one end side of the piezo vibration motor main body, and holds a lubricant therein. The pressing mechanism for a standing wave piezo vibration motor according to claim 1. The pressing mechanism for a standing wave piezo vibration motor according to claim 1, wherein the lubricant is an oil-based lubricant. The contact surface of the urging member disposed on one end side of the piezoelectric vibration motor main body is substantially perpendicular to the urging shaft when the vibration output terminal on the other end side is in urging contact with the driven object. The pressing mechanism for a standing wave piezo vibration motor according to any one of claims 1 to 3, wherein the pressing mechanism is for a standing wave type. A lens driving device for an imaging apparatus, wherein the standing wave type piezoelectric vibration motor including the pressing mechanism according to any one of claims 1 to 4 is used as a driving source for moving the lens in an optical axis direction. A lens driving device. A lens barrel using the lens driving device according to claim 5.

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