JP2010220797A - Piezoelectric actuator mounting structure for endoscope - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a piezoelectric actuator mounting structure for an endoscope by which a piezoelectric actuator the drive source of which is high-frequency vibration generated by a piezoelectric element is mounted to a member to be mounted without occurrence of a large drive loss and without need of a large space. <P>SOLUTION: Between the outer surface of the outer surface of the piezoelectric element 12 and the inner surface of a bracket 14, a clearance is formed. The clearance is filled with an elastic tape 22 which is made from a polymer and placed around the outer surface of the piezoelectric element 12. In another embodiment, the clearance is filled with an elastic adhesive 21. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an endoscope piezoelectric actuator mounting structure for mounting an ultra-small piezoelectric actuator to a mounted member of an endoscope.

  Many of the objective optical systems arranged at the distal end of the endoscope insertion part are fixedly arranged, but some or all of the lenses are movable in the axial direction to adjust the focus and focal length. Many of them have advanced functions that enable adjustment (zoom).

  In order to drive such a movable objective optical system, there is a type in which an ultra-small motor is arranged in the distal end of the insertion portion to directly drive the objective optical system. Such direct drive is superior in that the response is very good compared to remote drive from the operation unit (for example, Patent Document 1).

  However, the focus output and focal length adjustment of the objective optical system requires a slide operation in the axial direction, but the motor output is a rotation operation, so an operation conversion mechanism is required to convert the rotation operation into a slide operation. When the motor is arranged in the distal end of the operation part of the endoscope where the space is extremely limited, there is a case where it becomes a neck.

  Therefore, it is conceivable to use a piezoelectric actuator that can directly obtain a slide output by moving the screw rod as an output shaft in the axial direction simultaneously with the rotation operation instead of the motor (for example, Patent Document 2).

  The piezoelectric actuator described in Patent Document 2 and the like is generated when a plurality of piezoelectric elements are arranged in close contact with the outer peripheral surface of a nut-like member through which a female screw hole is formed, and driving power is applied to the piezoelectric element. The screw rod screwed into the female screw hole is rotationally driven by the high frequency vibration.

Japanese Patent Laid-Open No. 2005-52455 Special table 2007-505599

  The piezoelectric actuator as described in Patent Document 2 can directly obtain a slide output and can be configured to be extremely small. Therefore, it is suitable for being built in at the distal end of the insertion portion of the endoscope.

  However, in order to mount the piezoelectric actuator in a very small space such as in the distal end of the insertion portion of the endoscope, if the outer surface portion of the piezoelectric element placed in close contact with the outer surface portion of the nut-like member is pressed with a bracket or the like, the piezoelectric element The distortion operation of the element is restricted and a large driving loss occurs.

  However, in order not to disturb the operation of the piezoelectric element, if a rubber O-ring or the like is sandwiched between the piezoelectric element and the bracket, the space in the distal end of the insertion portion of the endoscope is considerably eroded. This is not preferable.

  The present invention provides a piezoelectric actuator for an endoscope that can attach a piezoelectric actuator that uses high-frequency vibration generated by a piezoelectric element to a mounting member without causing a large driving loss and without requiring a large space. An object is to provide an actuator mounting structure.

  In order to achieve the above object, an endoscope piezoelectric actuator mounting structure according to the present invention is an endoscope piezoelectric actuator mounting structure for mounting a piezoelectric actuator to a mounted member of an endoscope. A high frequency generated when a plurality of piezoelectric elements are arranged in close contact with the outer peripheral surface of a nut-like member having a female screw hole formed therethrough, and a screw rod screwed into the female screw hole applies drive power to the piezoelectric element. Driven by vibration and configured to move in the axial direction while rotating in the direction around the axis, and to surround and press the outer surface of a plurality of piezoelectric elements in order to fix the entire piezoelectric actuator to the mounted member In a tape provided with a bracket, a gap is formed between the outer surface of the piezoelectric element and the inner surface of the bracket, and the elastic tape is made of a polymer material. Are those which are filled in the gap in a state wound on the outer surface of the piezoelectric element, the tape may be formed of a foamed polymeric material.

  Further, instead of the tape, an elastic adhesive may be filled in the gap, and in that case, a window portion for filling the gap with the adhesive may be formed in the bracket.

  According to the present invention, a gap is formed between the outer surface of the piezoelectric element and the inner surface of the bracket, and a flexible tape made of a polymer material is filled in the gap while being wound around the outer surface of the piezoelectric element. Alternatively, the gap is filled with an elastic adhesive, so that a piezoelectric actuator that uses high-frequency vibration generated by the piezoelectric element as a drive source does not cause a large drive loss and requires a large space. It can attach to a to-be-attached member without.

1 is a perspective view of a piezoelectric actuator mounting structure for an endoscope according to a first embodiment of the present invention. FIG. It is sectional drawing of the piezoelectric actuator attachment structure of the endoscope which concerns on 1st Example of this invention. 1 is a circuit diagram of a piezoelectric actuator according to a first embodiment of the present invention. It is a perspective view which shows operation | movement of the piezoelectric actuator attachment structure of the endoscope which concerns on 1st Example of this invention. It is sectional drawing of the piezoelectric actuator attachment structure of the endoscope which concerns on 2nd Example of this invention.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a perspective view of a piezoelectric actuator mounting structure for an endoscope according to a first embodiment of the present invention, and FIG. 2 is a cross-sectional view in a direction perpendicular to the axis.

  The piezoelectric actuator 10 includes a screw rod 13 in which a plurality of piezoelectric elements 12 are arranged in close contact with an outer peripheral surface of a nut-like member 11 through which a female screw hole is formed, and a male screw is formed over the entire length of the outer peripheral portion. 11 is threaded into the female screw hole.

  The nut-like member 11 is formed in an elongated rectangular parallelepiped shape and has a female screw hole formed at an axial position thereof, and a rectangular piezoelectric element 12 is disposed in close contact with substantially the whole of the four outer peripheral surfaces of the nut-like member 11. Yes.

  As a result, the screw rod 13 screwed into the female screw hole is rotationally driven by high-frequency vibration (here, ultrasonic level vibration) generated by applying drive power to the piezoelectric element 12, and the screw rod 13 is rotated around the axis. It can move in the axial direction while rotating in the direction to directly obtain the slide output.

  As shown in FIG. 3 which is a circuit diagram, each piezoelectric element 12 is electrically connected to the drive circuit on both front and back surfaces. Then, driving power is applied to the two piezoelectric elements 12 at opposite positions and the two piezoelectric elements 12 arranged so as to be deflected by 90 ° with respect to each other due to the high-frequency vibration generated thereby. The screw rod 13 is driven to rotate. The principle of such an apparatus is known, for example, from JP-T-2007-505599, and detailed description thereof is omitted.

  Returning to FIGS. 1 and 2, reference numeral 14 surrounds and presses the outer surface portions of the plurality of piezoelectric elements 12 in order to fix the entire piezoelectric actuator 10 to, for example, the attached member 50 in the distal end of the insertion portion of the endoscope. It is a bracket for.

  The bracket 14 formed by bending a metal plate is formed when the portion surrounding the piezoelectric actuator 10 is formed in a U-shaped cross-section and the attached member 50 is positioned on the lower surface side of the piezoelectric actuator 10. 14 faces the left and right side surfaces and the upper surface of the piezoelectric actuator 10.

  However, as shown in FIG. 2, a gap is formed between the inner surface of the bracket 14 and the outer surface of each piezoelectric element 12 facing the bracket 14. A similar gap is also formed between the surface of the attached member 50 and the outer surface of the piezoelectric element 12 facing it.

  The size t of each gap is, for example, about 0.05 to 0.5 mm, and an elastic adhesive 21 is filled in each gap. As the adhesive 21, for example, a silicon-based adhesive having a high elasticity is used.

  The piezoelectric actuator 10 is bonded to the bracket 14 with such an adhesive 21 and is also bonded to the attached member 50. Depending on the situation, the adhesive 21 may not be bonded to the attached member 50, but is filled between the attached member 50.

  A mounting portion 15 facing the mounted member 50 is formed on the bracket 14 by being bent at a right angle from the lower ends of both the left and right wall portions, and the mounting portion 15 is laser spot welded or bonded to the mounted member 50. It is fixed with. If there is enough space, it may be fixed with screws.

  As shown in FIG. 1, a window portion 16 for filling an adhesive 21 into a gap between the outer surface of the piezoelectric element 12 and the inner surface of the bracket 14 is cut out in the intermediate portion of the bracket 14. The opening 21 is formed, and the adhesive 21 can be completely filled from the window portion 16 to the inner surface portion of the bracket 14.

  In the endoscope piezoelectric actuator mounting structure configured as described above, when driving power is applied to the piezoelectric element 12, the adhesive 21 is elastically associated with the distortion operation of the piezoelectric element 12, as schematically shown in FIG. Due to the deformation, the distortion operation of the piezoelectric element 12 is not so restricted by the bracket 14.

  Therefore, the screw rod 13 can be screw-driven by high-frequency vibration without causing a large drive loss, and a slide output can be directly obtained, and the piezoelectric actuator 10 can be attached to the attached member 50 without requiring a large space. Can be attached to.

  FIG. 5 is a cross-sectional view of a cross section perpendicular to the axis of the piezoelectric actuator mounting structure for an endoscope according to the second embodiment of the present invention. In this embodiment, an elastic tape 22 made of a polymer material is placed in the gap formed between the outer surface of the piezoelectric element 12 and the inner surface of the bracket 14 in the same manner as in the first embodiment. The gap is filled in a state wound around the outer surface of 12.

  The tape 22 is preferably formed of a foamed polymer material such as foamed PTFE (polytetrafluoroethylene) resin or foamed silicon resin. Even with such a configuration, the distortion operation of the piezoelectric element 12 is not so much restricted by the bracket 14, and the same effect as in the first embodiment can be obtained. In the case of this embodiment, the window portion 16 formed in the bracket 14 of the first embodiment is not necessary.

  In addition, this invention is not limited to the said Example, For example, the nut-shaped member 11 does not necessarily need to be a rectangular parallelepiped, and the piezoelectric element 12 has two or eight pieces on the outer peripheral surface of the nut-shaped member 11, or other Several arrangements may be possible. Further, the attached member 50 may be disposed outside the distal end of the insertion portion of the endoscope (for example, inside the operation portion).

DESCRIPTION OF SYMBOLS 10 Piezoelectric actuator 11 Nut-shaped member 12 Piezoelectric element 13 Screw rod 14 Bracket 16 Window part 21 Adhesive 22 Tape 50 Attached member

Claims (4)

An endoscope piezoelectric actuator mounting structure for mounting a piezoelectric actuator to an endoscope attached member,
In the piezoelectric actuator, a plurality of piezoelectric elements are arranged in close contact with the outer peripheral surface of a nut-like member through which a female screw hole is formed, and a screw rod that is screwed into the female screw hole applies driving power to the piezoelectric element. It is configured to move in the axial direction while being rotated by the high frequency vibration generated by the rotation and rotating in the direction around the axis,
In order to fix the entire piezoelectric actuator to the attached member, a bracket is provided for surrounding and pressing the outer surface portions of the plurality of piezoelectric elements.
A gap is formed between the outer surface of the piezoelectric element and the inner surface of the bracket, and the gap is filled with an elastic tape made of a polymer material wound around the outer surface of the piezoelectric element. A piezoelectric actuator mounting structure for an endoscope characterized by the above.   The endoscope actuator mounting structure for an endoscope according to claim 1, wherein the tape is formed of a foamed polymer material. An endoscope piezoelectric actuator mounting structure for mounting a piezoelectric actuator to an endoscope attached member,
In the piezoelectric actuator, a plurality of piezoelectric elements are arranged in close contact with the outer peripheral surface of a nut-like member through which a female screw hole is formed, and a screw rod that is screwed into the female screw hole applies driving power to the piezoelectric element. It is configured to move in the axial direction while being rotated by the high frequency vibration generated by the rotation and rotating in the direction around the axis,
In order to fix the entire piezoelectric actuator to the attached member, a bracket is provided for surrounding and pressing the outer surface portions of the plurality of piezoelectric elements.
A piezoelectric actuator mounting structure for an endoscope, wherein a gap is formed between an outer surface of the piezoelectric element and an inner surface of the bracket, and an elastic adhesive is filled in the gap.   The piezoelectric actuator mounting structure for an endoscope according to claim 3, wherein a window for filling the gap with the adhesive is formed in the bracket.

Images