JP4316350B2 - Ultrasonic motor and electronic device with ultrasonic motor - Google Patents

Description

  The present invention relates to an ultrasonic motor and an electronic apparatus with an ultrasonic motor, and more particularly to a support pressure structure for an ultrasonic motor.

In recent years, precise positioning has been required in various electronic devices. An ultrasonic motor has attracted attention as a driving source.
The component parts of the ultrasonic motor include a vibrating body, a pressure member, and a moving body that contacts the vibrating body. When a voltage is applied to the vibrating body, the vibrating body is excited. And it is the principle that a moving body which contacts a vibrating body receives a frictional force and generates a driving force by applying pressure to the vibrating body and the moving body by a pressing member.

An ultrasonic motor according to a conventional technique uses, for example, a rectangular vibrating body as shown in FIG. An example of a vibrator according to this conventional technique is shown in FIG. In FIG. 8, a structure is adopted in which a rectangular vibrating body 100 made of a piezoelectric element is supported so as to be sandwiched between elastic members 101. (See Patent Document 1)
Japanese Patent Laid-Open No. 09-037575 (FIG. 11)

  However, since the supporting and pressing structure shown in FIG. 8 only sandwiches the vibrating body 100 with the elastic member 101, the supporting member is deformed during driving or with time, and the position of the movable portion is shifted. The contact point between the vibrating body and the moving body may fluctuate and output characteristics may fluctuate. For the same reason, it is difficult to change the support conditions such as the support force of the vibrating body or to make the support conditions the same for each motor, which may lead to variations in motor characteristics.

  Therefore, an object of the present invention is to obtain a pressure support structure that stably supports the vibrating body and stabilizes the contact between the vibrating body and the moving body.

  In order to solve the above problems, the ultrasonic motor of the present invention employs the following configuration. That is, in an ultrasonic motor including a vibrating body made of a piezoelectric element, a moving body driven by vibration of the vibrating body, and a pressure member that applies pressure between the vibrating body and the moving body, It is characterized by having a projecting portion projecting from the vicinity of the node, a support member provided in the projecting portion and extending in the pressurizing direction, and a guide member for guiding the support member so as to be movable only in the pressurizing direction. According to this, even if a slight backlash occurs between the support member and the guide member, the support member can move only in the pressurizing direction, and the vibrating body does not rotate and moves only in the pressurizing direction. Therefore, the contact position between the vibrating body and the moving body is constant, the output of the ultrasonic motor is stabilized, and individual differences are less likely to occur.

Further, since the protruding portion protrudes from the vicinity of the vibration node of the vibration body, the vibration loss of the vibration body can be reduced near the vibration node of the vibration body.
In the present invention, the protrusion is provided on the side surface in the width direction and the center in the longitudinal direction of the vibrating body. According to this, the support structure can be thinned by providing the protruding portion on the side surface in the width direction of the vibrating body and in the center in the longitudinal direction.

  Further, the present invention is characterized in that the protruding portion is provided on the side surface in the thickness direction of the vibrating body and on the center in the longitudinal direction and the width direction. According to this, by providing the protruding portion on the side surface in the thickness direction of the vibrating body and in the center in the longitudinal direction and the width direction, it becomes possible to provide a space near the side surface of the vibrating body, thereby increasing the degree of design freedom. It becomes possible.

  In the present invention, the support member and the guide member are in contact with each other at a position avoiding the extended portion of the protruding portion. According to this, the portion directly supporting the vibrating body does not come into contact with the guide member, and the vibration loss of the vibrating body can be reduced, and the support conditions are stable.

  In the present invention, the pressurizing member pressurizes the protruding portion or the support member. According to this, since the pressing member does not contact the vibrating body, it is possible to reduce the vibration loss of the vibrating body.

  According to the present invention, an electronic apparatus with an ultrasonic motor using any of the ultrasonic motors described above is proposed. According to this, the energy loss of the electronic apparatus with an ultrasonic motor is small, and stable driving is possible.

  An ultrasonic motor according to the present invention includes a protruding portion protruding from the vicinity of a vibration node of a vibrating body, a supporting member provided on the protruding portion and extending in a pressing force direction, and the supporting member can be moved only in the pressing force direction. A guide member is provided for guiding in a similar manner. As a result, the vibrating body can move stably in the applied pressure direction, but does not displace in a direction perpendicular to the applied pressure, so that the contact between the vibrating body and the moving body is constant. As a result, the output characteristics of the motor become stable, and the output characteristics of the individual motors are less varied.

  Further, the support structure can be thinned by providing the protruding portion on the side surface in the width direction of the vibrating body and in the center in the longitudinal direction.

  In addition, by providing the protruding portion on the side surface in the thickness direction of the vibrating body and in the center in the longitudinal direction and the width direction, it is possible to provide a space near the side surface of the vibrating body, thereby increasing the degree of design freedom. .

The support member and the guide member are brought into contact with each other at a position avoiding the extended portion of the protruding portion, thereby avoiding fluctuations in motor output characteristics caused by the support structure.
In the electronic apparatus with an ultrasonic motor using the ultrasonic motor described above, the contact between the vibrating body and the moving body is constant and stable motor driving is possible, so there is no individual variation and stable performance can be obtained. .

(Embodiment 1)
Hereinafter, a first embodiment to which the present invention is applied will be described with reference to FIGS.

  FIG. 1 is a diagram illustrating an ultrasonic motor according to the first embodiment. FIG. 1A shows the overall configuration of the ultrasonic motor. FIG. 1B shows the A-A ′ cross section in FIG.

  The ultrasonic motor according to the first embodiment pressurizes the vibrating body 1, the protruding portion 5 protruding from the vicinity of the vibration node of the vibrating body 1, the supporting member 6 extending in the pressurizing direction, and the supporting member 6. A guide member 7 having a guide groove 7a that guides in the same direction as the direction, a moving body 3 that contacts the vibrating body 1 and moves by frictional force, and a pressurizing member 4 that applies pressure to the vibrating body 1 and the moving body 3 The moving body guide member 8 guides the movement of the moving body 3 and the fixing member 9 fixes the moving body guide member 8. As shown in FIG. 1, the vibrating body 1 may be provided with a protrusion 2 for making the contact point constant at a position where it makes contact with the moving body 3.

  The vibration body 1 is excited by the application of a voltage to generate two vibrations of longitudinal vibration and bending vibration shown in FIG. The moving body 3 that comes into contact with the protrusion 2 receives pressure from the pressing member 4 and moves in a linear direction by frictional force.

  As the vibrating body 1, a single piezoelectric element such as lead zirconate titanate is used.

  The protrusion 2 may be attached with an engineering plastic having excellent wear resistance processed into a rectangular shape.

  The material of the projecting portion 5 and the support member 6 may be a metal such as stainless steel, and if electrical insulation is required, it may be a highly rigid engineering plastic or ceramics. The projecting portion 5 and the support member 6 are integrated. It may be produced, or may be integrated by separately producing and bonding.

  Since the support member can move only in the pressurizing direction and extends in the pressurizing direction, the vibrating body can move stably in the pressurizing direction, but does not move in other directions, such as a rotational operation. For this reason, the contact position between the vibrating body and the moving body is constant, the output of the motor is stabilized, and the output of each motor is less likely to vary.

FIG. 2 is a diagram showing an ultrasonic motor different from FIG. 1 according to the first embodiment.
FIG. 2A shows the overall configuration of the ultrasonic motor. 2B is a cross-sectional view taken along the line AA ′ in FIG. 2A, and the vibrating body 1 is formed by sandwiching the elastic material 15 with a plurality of piezoelectric elements 10, and the protruding portion 5 is bonded to the side surface of the vibrating body. Indicates. 2C similarly shows the AA ′ cross-sectional portion of FIG. 2, and the vibrating body 1 is configured by sandwiching the elastic material 15 such as a metal with a plurality of piezoelectric elements 10, and the elastic material 15 and the protruding portion 5 shows a state in which they are integrally formed.

  In the case of the structure shown in FIG. 2B, as in the example shown in FIG. 1, the position of the vibrating body does not fluctuate in the direction perpendicular to the applied pressure acting on the vibrating body and the moving body, Since no rotational force is applied to the body, the contact between the vibrating body and the moving body is stabilized. As a result, the output of the motor becomes stable and variations in the output of each motor are less likely to occur.

  In the case of the structure shown in FIG. 2C, in addition to the effect of the structure shown in FIG. 2B, the elastic member 15 and the protruding portion 5 are integrated to bond the vibrating body 1 and the protruding portion 5 together. It is also possible to reduce vibration loss at the portion. The moving body 3 can be configured not only in a linear motion but also as a rotary ultrasonic motor by making the moving body shape a disk.

  FIG. 3 is a diagram illustrating an example of a vibration mode excited by applying a voltage to the vibrating body 1 according to the first embodiment. For example, a bending vibration mode and a longitudinal vibration mode are excited by applying a voltage to the vibrating body 1, an elliptical motion is drawn at one end in contact with the moving body, and the moving body is moved by a frictional force. By providing the protruding portions 5 at the vibration node positions in the bending vibration mode and the longitudinal vibration mode, vibration loss is reduced.

  FIG. 4 is a diagram illustrating a configuration when a cutout portion is provided in the support member of the ultrasonic motor according to the first embodiment.

A cutout portion 16 is provided so that the support member 6 does not come into contact with a guide groove (not shown) on an extension line at a position where the protruding portion 5 is provided. Thereby, since the contact pressure with the guide groove is not applied to the protrusion 5 or the vibrating body in a straight line, the vibration loss of the vibrating body can be reduced and the vibration loss can be stabilized.
(Embodiment 2)
Hereinafter, Embodiment 2 will describe in detail a pressurizing structure that applies pressure to the vibrating body and the moving body.

  FIG. 5A shows the case where the pressure from the pressure member is applied to one point of the vibrator, and FIG. 5B shows the case where the pressure from the pressure member is applied to the support member provided on the support member. FIG. 5C is a diagram showing a case where the pressure from the pressure member is applied to the protrusion.

  When pressure is applied to the position shown in FIG. 5 (a), since the pressure is applied to at least one point of the vibrating body or the vibrating body, the rigidity of the protruding portion and the supporting member can be reduced. The vibration loss at the support portion can be reduced, and the vibration body or the pressure applied to the vibration body can be increased, so that the ultrasonic motor can have high torque and high driving force.

  When pressure is applied to the position shown in FIG. 5B, since the pressing member does not contact the vibrating body or the vibrating body, it is possible to reduce the vibration loss of the vibrating body or the vibrating body.

When pressure is applied to the position shown in FIG. 5C, for example, a coil spring-shaped pressure member can be provided in the vibration body or a space between the vibration body and the support member, so that the ultrasonic motor The whole can be downsized.
(Embodiment 3)
Hereinafter, Embodiment 3 to which the present invention is applied will be described with reference to FIG.

  FIG. 6A shows the vibrator 1, the support member 6, and the protrusion 5 used in the ultrasonic motor according to the third embodiment. The protrusion 5 is provided on the side surface in the thickness direction of the vibrating body 1 and in the longitudinal direction and the center in the width direction.

  FIG. 6B shows a guide member 7 having a guide groove 7a through which the support member 6 is guided, and FIG. 6C shows a state in which the entire configuration is viewed from the side.

  As in the first embodiment, since the support member 6 extends in the pressurizing direction, the vibrating body 1 moves only in the pressurizing direction, so that the contact between the vibrating body 1 and the moving body (not shown) is constant. Become. This stabilizes the motor drive. Here, the support member 6 is prevented from coming into contact with the guide member 7 by providing a notch 6a at a position where the protruding portion extends.

Further, by providing the protrusions 5 on the side surfaces in the thickness direction, the protrusions 5 can be provided at the complete nodes of the bending vibration mode and the longitudinal vibration mode, so that the vibration loss is extremely small. Moreover, it becomes possible to provide an empty space in the side surface of the vibrating body 1, and it becomes possible to raise the freedom degree of design.
(Embodiment 4)
Hereinafter, a fourth embodiment to which the present invention is applied will be described with reference to FIG.
FIG. 7 shows an electronic apparatus with an ultrasonic motor according to the fourth embodiment, and specifically shows a calendar mechanism structure of a wristwatch with a calendar.

  The electronic apparatus with an ultrasonic motor according to the fourth embodiment guides the vibrating body 1, the protrusion 2 provided on the vibrating body 1, the pressing member 4, the protruding portion 5, the support member 6, and the support member 6. It comprises a guide member 7, a rotor 11 that contacts the projection 2, rotates around the rotation shaft 4 and has a gear portion 13 that is a gear, and a dial plate 10 on which the date is written. The gear portion 13 meshes with the inner periphery of the dial plate 10, and the dial plate 10 obtains rotational force to drive the calendar mechanism.

  Since the ultrasonic motor used in the electronic apparatus with the ultrasonic motor uses the ultrasonic motor according to the first to third embodiments, the support of the vibrating body 1 is stable, and the positional deviation between the vibrating body 1 and the moving body 3 is maintained. Since there is no contact, the contact with the rotor 11 is constant, so that a stable calendar mechanism can be driven. In addition, since the vibration loss at the support portion is extremely small, the efficiency is high and the drive can be performed at a low voltage, so that the battery can be sufficiently driven. And since the structure of the whole motor is small, a small electronic device (timepiece) can be realized.

It is a figure which shows the ultrasonic motor which concerns on Embodiment 1 of this invention. It is a figure which shows the ultrasonic motor which concerns on Embodiment 1 of this invention. It is a figure which shows the structure of the supporting member which concerns on Embodiment 1 of this invention. It is a figure which shows another structure of the ultrasonic motor which concerns on Embodiment 1 of this invention. FIG. 10 is a diagram illustrating a pressure structure of an ultrasonic motor according to the second embodiment of the present invention. It is a figure which shows the ultrasonic motor which concerns on Embodiment 3 of this invention. It is a figure which shows the electronic device with an ultrasonic motor which concerns on Embodiment 4 of this invention. It is a figure which shows the structure of the ultrasonic motor by a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Vibrating body 2 Protrusion 3 Moving body 4 Pressure member 5 Protruding part 6 Support member 7 Guide member 7a Guide groove 8 Moving body guide member 9 Fixed member 10 Piezoelectric element 11 Rotor 12 Rotating shaft 13 Gear part 14 Dial 15 Elastic member 16 Notch

Claims (6)

A vibrating body composed of a piezoelectric element, a moving body driven by the vibration of the vibrating body, a pressurizing member that applies pressure between the vibrating body and the moving body, and protruding from the vicinity of a vibration node of the vibrating body In an ultrasonic motor comprising a protrusion and a support member provided integrally with the protrusion and extending in the pressurizing direction,
An ultrasonic motor comprising a guide member that engages with the support member and has a guide groove that allows the support member to move only in the pressurizing direction.   The ultrasonic motor according to claim 1, wherein the protrusion is provided on a side surface in a width direction and a center in a longitudinal direction of the vibrating body.   The ultrasonic motor according to claim 1, wherein the protruding portion is provided on a side surface in the thickness direction of the vibrating body and on a center in a longitudinal direction and a width direction.     The ultrasonic motor according to claim 1, wherein the support member and the guide member are in contact with each other at a position avoiding an extension of the protruding portion.   The ultrasonic motor according to claim 1, wherein the pressure member pressurizes the protrusion or the support member.   An electronic apparatus with an ultrasonic motor, comprising the ultrasonic motor according to claim 1, wherein an operating unit is driven by the ultrasonic motor.

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