JPH04308485A - Oscillator - Google Patents

Abstract

PURPOSE:To suppress influence onto the oscillation of an oscillator being employed in a pencil type ultrasonic motor, to simplify wiring and to prevent lateral shift at the time of assemblage of electrode plates by decreasing the number of electrode plates having external power supply terminals as low as possible among the electrode plates constituting the oscillator. CONSTITUTION:A common ground electrode 22 is provided with an external power supply terminal and contact chips 22a contacting with a bolt 12. Other ground electrode plates 21, 23 are not provided with external power supply terminal but the electrode plate 23 is oppositely provided with a contact chip 23a contacting with the bolt 12. Ground voltage is fed through the bolt 12 and a metal block 1 to the electrode plate 21 contacting directly with the metal block 1 and through the bolt 12 to the electrode plate 23.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a vibration generating element such as a piezoelectric element, and a member pressed against the vibrating body, such as a rotor, by the vibration generated in the vibrating body that vibrates in response to the vibration from the piezoelectric element. The present invention relates to an ultrasonic vibrator for a vibrating motor that relatively moves a vibrator and a vibrating body, particularly a vibrator of a pencil-shaped motor (hereinafter referred to as a pencil-type motor) or a Langevin type vibrator.

0002

[Prior Art] A group of vibration generating drive parts is made by stacking two vibration generating elements such as piezoelectric elements, and these two groups are used as a vibration driving source, and these two groups of laminated piezoelectric elements are used as a vibration driving source. A vibrator has been proposed in which metal blocks as a vibrating body are arranged on both sides of the vibrator, and a piezoelectric element is sandwiched between these metal blocks, and these metal blocks are fastened together using a fastening member such as a bolt.

[0003] Electrode plates for supplying voltage to the piezoelectric elements are interposed between the stacked piezoelectric elements, and AC voltage from a drive circuit (not shown) is applied to each piezoelectric element via these electrode plates. is supplied to

A conventional vibrator will be briefly explained with reference to FIG.

1 and 2 are front and rear metal blocks forming a vibrating body; 4, 5, 6, and 7 are piezoelectric elements as electro-mechanical energy conversion elements made of PZT, etc.; 8, 9, 10, 1
Reference numeral 1 denotes an electrode plate, in which piezoelectric elements 4 and 5 constitute a group of vibration generating drive sections (hereinafter referred to as A phase), and piezoelectric elements 6 and 7 constitute a group of vibration generation drive sections (hereinafter referred to as B phase). The male threaded part 12a of the fastening bolt 12 inserted from the rear metal block 2 side is connected to the female threaded part 1 of the front metal block 1.
By screwing into a, the members constituting these vibrators are integrated.

[0006] Electrode plate 8 for ground and electrode plate 9 for A phase.
An AC voltage is applied from the A-phase driving AC source circuit 13, and an AC voltage from the B-phase driving AC power circuit 14 is applied to the ground electrode (common ground electrode) 10 and the B-phase electrode plate 11. A voltage is applied, the ground electrode plate 8 is in electrical contact with the conductive front metal block 1, and the common ground electrode 10 is connected to the A phase and B phase.
Connected to the ground side outputs of the phase drive AC power supply circuits 13 and 14, the conductive rear metal block 2 is electrically connected via the conductive fastening bolt 12, and then the metal block 2 Since the electrode plate 7 is in electrical contact with the electrode plate 7, a voltage of the same potential as the electrode plate 5 is applied to the electrode plate 7.

Therefore, the inner diameter of each piezoelectric element 4 to 7 is made smaller than the outer diameter of the bolt 12, so that the bolt 12 does not come into direct contact with the electrodes formed on the front and back surfaces of the piezoelectric element.

The vibrator shown in FIG. 5 is used as a vibrator for a pencil type motor, and although it will not be described in detail here, it has a small diameter shaft portion 12 provided at the tip of the bolt 12.
A rotor (not shown) that comes into contact with the front end surface of the front metal block 1 is arranged around a, and the vibrator itself is attached to the small diameter shaft part 12.
It is fixed to a case or the like to which a pencil type motor is attached by a fixing member (not shown) fixed to the tip of the small-diameter shaft 12a, and the fixing member is a non-illustrated fixing member that is screwed onto the tip threaded portion 12b of the small diameter shaft portion 12a. It is fixed with the illustrated nut.

[0009] Such a pencil type motor can be miniaturized to be even smaller than the little finger of a human hand, and the electrode plate 8
The power supply terminal portions 8a to 11a extending radially outward in portions 8a to 11a become a factor of imbalance in the vibration system of the vibrator, and have a considerable influence on vibration, so it is desirable to reduce them as much as possible. There is a demand.

Further, as shown in FIG. 6, these power supply terminal portions 8a to 11a are close to each other in the vertical direction, and there has been a demand to reduce the number of these power supply terminal portions as much as possible in order to simplify wiring, soldering, etc. Note that the vibrator shown in FIG. 6 is provided with piezoelectric elements 15 and 16 for sensors in addition to the piezoelectric element for driving.
Similarly, a ground electrode plate 17 and a sensor electrode plate 1 are provided, and these electrode plates 17 and 18 are also provided with terminal portions 17a and 18a, respectively. Similarly, the influence on vibration, wiring,
There are problems with soldering etc.

[0011] Furthermore, Japanese Utility Model Publication No. 3-3482 discloses an electrode plate without an external terminal that is provided with a protrusion that comes into contact with a tightening bolt. Therefore, during assembly, there was a problem in that the electrode plate itself would shift laterally due to the reaction force of this protrusion (reaction force generated when inserting and tightening bolts, etc.). Of course, when this electrode plate is used as a vibrator for the above-mentioned pencil type motor, the presence of only one protrusion may cause an imbalance in the vibration system.

0012

[Problems to be Solved by the Invention] The problems to be solved by the present invention are that the electrode plate shifts laterally during assembly, and that the power feeding terminal portion of the electrode plate that contacts the piezoelectric element of the vibrator is affected by the vibration of the vibrator. The effects of proximity to wiring, soldering, etc. impair workability and affect vibration characteristics.

The purpose of the present invention is to reduce the number of terminals on the electrode plate as much as possible, to reduce the influence on vibration, to make wiring and soldering work easier, and to reduce vibration without causing the electrode plate to shift laterally during assembly. It is about providing children.

[0014]

[Means for Solving the Problems] A configuration for realizing the object of the present invention includes an electro-mechanical energy conversion element that generates vibration in response to an electric signal supplied through an interposed electrode plate. In a vibrator that is arranged in a stacked manner and integrated by fastening conductive blocks arranged at both ends so as to sandwich them with a conductive fastening member, the vibrator excites vibration in the conductive blocks. Among the plurality of electrode plates, only one of the electrode plates to which a voltage of the same potential is supplied is provided with a terminal portion for power supply, and a contact member that comes into contact with the fastening member is formed, and a voltage of the same potential is connected to the other electrode plate. The present invention is characterized in that a contact member that contacts the fastening bolt faces the electrode plate to which power is applied, so that a voltage of the same potential is supplied to the electrode plate.

[0015]

[Function] In the vibrator having the above-mentioned configuration, if three electrode plates are arranged for grounding, a terminal part for power feeding is formed only on the middle electrode plate among them, and the other two electrode plates are arranged. The two ground electrode plates are electrically conductive blocks and
Assuming that a pair of contact pieces is interposed between the mechanical energy conversion elements and contacts a fastening member such as a bolt on each of the other two electrode plates excluding the end electrode plate, the three ground electrodes are , just by supplying voltage to the middle electrode plate,
A voltage of the same potential will be supplied via the fastening member. Further, when a fastening member such as a fastening bolt is inserted and tightened, since the contact pieces of the electrode plate are provided as a pair facing each other, the insertion of the fastening bolt does not cause the electrode plate to shift laterally to one side.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an exploded perspective view showing an embodiment of a vibrator according to the present invention, and FIG. 2 is a sectional view thereof.

In the vibrator of this embodiment, the piezoelectric elements 4 and 5 for driving the A phase, the piezoelectric elements 6 and 7 for driving the B phase, and the piezoelectric elements 15 and 16 for the sensor phase are all symmetrical about the diameter line. It has element parts polarized to different polarities, and electrode plates 21, 9, 22,
11, 23, and 18 are interposed between the piezoelectric elements.

The electrode 22 corresponds to the common ground electrode 10 in the conventional vibrator shown in FIG.
A contact piece 2 extending inward from the outside diameter of the bolt 12 on the inside diameter part.
2a is formed symmetrically so as to be in contact with the bolt 12 for electrical continuity. Further, the electrode plate 21 that contacts the front metal block 1 is not provided with a connecting terminal portion, and is made to have the same potential as the common ground electrode 22 via the bolt 12 and the front metal block 1.

The electrode 23 interposed between the B-phase driving piezoelectric element 7 and the sensor piezoelectric element 7 corresponds to the electrode plate 17 of the conventional vibrator shown in FIG. A contact piece 23a similar to the common ground electrode 22 is formed on the inner diameter part, and the contact piece 23a is electrically connected to the bolt 12 via the contact piece 23a. Therefore, a voltage having the same potential as that of the common ground electrode 22 is applied to the electrode 23.

As described above, in this embodiment, the ground voltage for the A-phase and B-phase driving piezoelectric elements is not individually supplied from the driving power supply circuit as in the conventional case, but is supplied from the common ground electrode 22. Since power can be supplied only to the other ground electrodes 21 and 23 via the bolt 12, there is no need for any special connection terminals for these ground electrodes 21 and 23, and the wiring is simple as shown in Figure 2. This also improves soldering workability.

Furthermore, since the number of electrode plates having terminal portions is reduced,
The unbalance of the vibrator seen from the vibration system is reduced,
The influence on vibration is reduced accordingly. In particular, when used in ultra-small pencil-type motors, the mass of solder applied to the terminals is quite large, so if the influence of the mass of solder can be reduced even a little, the motor can be driven with high precision. can do.

On the other hand, in this embodiment, in addition to the effect from the vibration system and the effect from the electrical connection of the vibrator, there is an effect of preventing the electrode plate from shifting laterally during assembly.

This effect of preventing lateral slippage is achieved by forming a pair of contact pieces facing each other on the electrode plate, so that when the fastening bolt is inserted, it will not be pushed to one side by contact with the bolt, and therefore it can be assembled without lateral slippage. become.

FIG. 3 shows a sectional view of a pencil type motor using the vibrator shown in FIG.

30 is a rotor, and 31 is a gear portion 31a on the outer periphery.
The rotor 30 is in contact with the front end surface of the front metal block 1, and the output member 31 is in contact with the rotor 30. The output member 31 is held by a sleeve member 32 via a bearing 33, and the rotor 30 is rotated by a pressure spring 34 elastically mounted on the sleeve member 32.
1, etc., and is pressed against the front metal block 1. 35
is a fixing member, which is inserted until its insertion cylinder part 35a comes into contact with the flange part 12b formed at the tip of the bolt 12, and by screwing a nut 36 onto the threaded tip part 12c, vibration is applied to the fixing member 35. The child is fixed directly.

The pencil type motor constructed in this manner applies a predetermined voltage to the piezoelectric element plates 4 to 7 through the electrode plates 9, 22, 1.
By supplying power through the connection terminals 1 and 18, the surface particles on the front end surface of the front metal block 1 perform a circular or elliptical motion, the rotor in frictional contact therewith rotates, and the rotation output member 31 rotates. do.

Various usage examples of such a pencil type motor can be considered, but the gear part 31 of the rotation output member 31
For example, a can be meshed with an input gear of a gear reduction device, and the output section of the device can be used as an AF (autofocus) motor, for example, to rotate the lens barrel of a photographic lens of a camera.

In this embodiment, two contact pieces 22a of the common ground electrode 22 are formed facing each other at a pitch of 180°, but as shown in FIG.
Four contact pieces 23a may be formed at a pitch, and four contact pieces 23a may also be formed at a 90° pitch on the inner diameter portion of the electrode plate 23, as shown in FIG. You can.

On the other hand, an electrode plate 22,
Concave groove 1 into which the contact pieces 22a and 23a formed in 23 fit
When 2d is recessed, rotation of the electrode plate can be prevented and positioning can be easily performed.

[0030]

Effects of the Invention As explained above, according to the present invention, the electrode plate interposed for applying voltage to an electro-mechanical energy conversion element such as a piezoelectric element has a terminal portion for external power supply as much as possible. It is no longer necessary to form a wire, which reduces the impact on vibration and simplifies wiring, etc.
Also, the electrode plate will not shift laterally during assembly.

[Brief explanation of drawings]

FIG. 1 is an exploded perspective view showing an embodiment of a vibrator according to the present invention.

FIG. 2 is a cross-sectional view of FIG. 1.

FIG. 3 is a cross-sectional view of a pencil-type motor using the vibrator shown in FIG. 1.

FIG. 4 is a plan view showing another example of the electrode plate.

FIG. 5 is an exploded perspective view of a conventional vibrator.

FIG. 6 is a cross-sectional view of FIG. 5;

[Explanation of symbols]

1, 2...metal block 4
~7, 15, 16... Piezoelectric element plates 8-11, 17, 18... Electrode plates 21, 22
, 23...electrode plates 22a, 23a...contact piece

Claims (1)

[Claims] [Claim 1] Electro-mechanical energy conversion elements that generate vibrations in response to electrical signals supplied through interposed electrode plates are arranged in a stacked manner, and are arranged at both ends so as to sandwich them. In the vibrator, which is integrated by connecting the conductive blocks with each other using a conductive fastening member, and which excites vibration in the conductive blocks, a voltage of the same potential is supplied to the plurality of electrode plates. A terminal portion for power supply is provided on only one of the electrode plates, and a contact member is formed in contact with the fastening member, and another electrode plate to which a voltage of the same potential is applied for power supply is in contact with the fastening bolt. A vibrator characterized in that contact members are formed to face each other and are supplied with voltages of the same potential.