JPH04308486A - Oscillator - Google Patents

Abstract

PURPOSE:To ensure an oscillation suitable for the oscillator of a pencil type motor and to superpose the external power supply terminal parts of electrode plates mounted on the oscillator in the axial direction. CONSTITUTION:Piezoelectric elements 3 constituting a piezoelectric element group for driving phase A are disposed while shifting the phase by 90 deg. from the piezoelectric elements constituting a piezoelectric element group for driving phase B. Electrode plates having external power supply terminal parts are then disposed between respective piezoelectric elements of these piezoelectric element groups so that the external power supply terminal parts are arranged with phase shift of 45 deg. which is equal to half of the phase difference between the phase A driving piezoelectric element group and the phase B driving piezoelectric element group.

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, and particularly to a vibrator for a pencil-shaped motor (hereinafter referred to as a pencil-type motor).

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 metal block is placed as a vibrating body on both sides, a piezoelectric element is placed between these metal blocks, and an electrode plate is interposed between these piezoelectric elements to supply voltage from an external power source to the piezoelectric element. However, a vibrator has been proposed in which these metal blocks are fastened together using a fastening member such as a bolt while holding the piezoelectric element and electrode plate therebetween.

A conventional vibrator will be explained based on FIG. 3.

1 and 2 are front and rear metal blocks forming a vibrating body; 3, 4, 5, and 6 are piezoelectric elements as electro-mechanical energy conversion elements made of PZT, etc.; 7, 8, 9, and 10.
is an electrode plate, in which the piezoelectric elements 3 and 4 constitute a group of vibration generation drive parts (hereinafter referred to as A phase), and the piezoelectric elements 5 and 6 constitute a group of vibration generation drive parts (hereinafter referred to as B phase), respectively. and the fastening bolt 1 inserted from the rear metal block 2 side.
The male threaded part 11a of 1 is the female threaded part 1a of the front metal block 1.
The members constituting these vibrators are integrated by screwing them into one.

[0005] Electrode plate for ground (common ground electrode)
8 and the electrode plate 7 for the A phase are supplied with AC voltage from an AC power supply circuit (not shown) for driving the A phase, and the electrode 10 for grounding and the electrode plate 9 for the B phase are supplied with the AC voltage for driving the B phase. AC voltage is supplied from an AC power supply circuit (not shown). A ground electrode plate 10 is in electrical contact with the conductive rear metal block 2, and a common ground electrode 8 is connected to the ground side outputs of the A-phase and B-phase driving AC power circuits 13 and 14. The conductive rear metal block 2 is electrically connected to the common ground electrode 8 and the front metal block 1 via conductive fastening bolts 11.

The vibrator shown in FIG. 3 is used as a vibrator for a pencil type motor, and is arranged around a small-diameter shaft portion 15 implanted at the tip of a bolt 11 and in contact with the front end surface of the front metal block 1. a rotor 12 in contact with the rotor 12; an output member 13 having a gear 13a on the outer periphery in contact with the rotor 12;
A sleeve member 16 that is installed inside via a bearing 14
The rotor 12 is pressed against the front metal block 1 by a pressure spring 17 elastically mounted between a stopper plate 18 fixed to the tip of the small diameter shaft portion 15 and the sleeve member 16. .

[0007] Such a pencil type motor can be miniaturized to be even smaller than the little finger of a human hand, and the electrode plate 7
The power feeding terminal portions 7a to 10a extending radially outward at points 7a to 10a become unbalanced factors in the vibration system of the vibrator, have a considerable influence on vibration, and There is a demand to minimize the influence of the department as much as possible.

[0008] Furthermore, the orientation of the power supply terminals 7a to 10a is not particularly stipulated, so it differs for each vibrating body, and is usually determined by wiring between power supply circuits using lead wires. For example, as shown in FIG. 3(a), they are arranged at different positions (angles) in the circumferential direction.

However, when these terminal portions 7a to 10a are connected to the power supply circuit using a flexible printed wiring board, there is a problem that the flexible printed wiring board becomes unnecessarily large and complicated due to the large spacing between the terminals. There is.

Furthermore, since these terminal portions 7a to 10a do not overlap in the axial direction, when actually arranging the vibrator, in the example of FIG. It is necessary to provide a maximum of four reliefs, and there is a problem in that this results in a significant waste of space when used in a pencil-type motor that allows for ultra-miniaturization.

[0011]

Problems to be Solved by the Invention The problems to be solved by the present invention are that the power supply terminal portion of the electrode plate that contacts the piezoelectric element of the vibrator affects the vibration of the vibrator depending on its placement position; Since the plurality of terminal parts are positioned in different directions, it is not suitable for connection with a flexible printed wiring board, and also requires a large amount of extra space around the vibrator.

[0012] An object of the present invention is to provide a vibrator that has less influence on vibration and can reduce the connection with a flexible printed wiring board and the wasted space around it as much as possible.

[0013]

[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. The plurality of electro-mechanical energy conversion elements arranged in a stacked manner were divided into two into an A-phase drive group and a B-phase drive group, and these electro-mechanical energy conversion elements and electrode plates were placed at both ends thereof so as to be sandwiched therebetween. In the vibrator which is integrated by fastening the vibrating body blocks with a fastening member and which vibrates by combining the vibrations excited by the A-phase drive group and the B-phase drive group in the vibrator block, the plurality of electrodes are integrated. Each external power supply terminal part of the plate is arranged in a superimposed position in the axial direction, and the external power supply terminal part is a conjugate of a vibration system vibrated by the A-phase drive group and a vibration system vibrated by the B-phase drive group. It is characterized by its location.

[0014]

[Function] In the vibrator having the above configuration, the external power supply terminals of the electrode plates are overlapped in the axial direction, but they are not placed at arbitrary positions, but for example, the A-phase drive group and the B-phase drive group
Assuming that they are arranged with a phase shift of 0 degrees, by arranging the external power supply terminal part of the electrode plate at a position with a phase shift of 45 degrees, which is the middle of the phase shift, the A-phase drive group and The mechanical impedance of each vibration system by the B-phase drive group becomes equal, and desired vibration can be given to the vibrator by combining the vibrations of both vibration systems.

[0015]

Embodiment FIGS. 1 and 2 show an embodiment of a vibrator according to the present invention. The vibrator shown in FIG. 1 is used in a pencil type motor and has the same basic structure as the conventional example shown in FIG.

The piezoelectric element plates 3 to 6 constituting the vibrator in this embodiment have the same structure. Taking the piezoelectric element plate 3 shown in FIG. 2 as an example, it has a disk shape with an inner diameter part. The piezoelectric element plate 3 has an electrode film 3A on both sides of the slit part 3C in which no electrode film is formed in the diameter line part as a boundary.
and 3B are formed, and the regions of these electrode films 3A and 3B are polarized in different polarization directions. The piezoelectric elements 3 and 4 forming the A phase for driving are stacked with their polarities reversed (180 degrees out of phase) with the central slit portions 3C aligned, and piezoelectric elements 3 and 4 forming the B phase for driving The piezoelectric elements 5 and 6 have a phase of 180° as in the case of the A phase above.
Although they are overlapped with a degree shift, they are arranged with a phase shift of 90 degrees with respect to the A phase. That is, the slit portion 5C of the piezoelectric element 5 is perpendicular to the slit portion 3C of the piezoelectric element 3.

On the other hand, the electrode plates 7 to 10 interposed between these piezoelectric elements are aligned such that their terminal portions 7a to 10a are overlapped in the axial direction, and these terminal portions 7a to 10a are They are arranged with a phase angle α shifted from the slit 3C of the element 3, and in this embodiment, the A-phase piezoelectric element group for driving and the B-phase piezoelectric element group for driving have a phase shift of 90 degrees. Because of the arrangement, the phase angle α is set to 45 degrees.

In other words, in order to cause the vibrator to vibrate only in its length direction, it is not necessary to provide a two-phase piezoelectric element group; rather, vibrations with different phases are excited by the two-phase piezoelectric element group, and as a result of the synthesis, In order to generate a swing-like vibration in the vibrator and frictionally drive the rotor 12 by circular or elliptical motion formed on the surface of the tip of the vibrator, a vibration system vibrating by a group of A-phase drive piezoelectric elements; It is most desirable that the vibration systems vibrated by the B-phase drive piezoelectric element group be equivalent.

However, the terminal portion extending from the electrode plate is 1
This impedes the symmetry of the vibrator, and in the conventional arrangement shown in FIG. There is a difference in mechanical impedance between directional vibration and radial vibration,
This makes it impossible to cause the vibrator to perform the oscillation motion that draws a substantially perfect circle as described above.

On the other hand, as in this embodiment, the position of the electrode plate is set at a conjugate position where the phase angle is shifted by 45 degrees, which is equivalent to the vibration system of the A-phase piezoelectric element group and the vibration system of the B-phase piezoelectric element group. By positioning it in such a way that there are no mechanical impedance differences and therefore no effect on motor performance.

[0021]

As explained above, according to the present invention, the plurality of electrode plates interposed for applying voltage to an electro-mechanical energy conversion element such as a piezoelectric element have terminal portions thereof By being placed one on top of the other in the axial direction,
It is possible to connect without making the flexible printed wiring board itself complicated or large, and since it is placed facing a specific position relative to the piezoelectric element, it is possible to avoid the effect on vibration of the terminal part. .

[Brief explanation of drawings]

FIG. 1 is a sectional view showing one embodiment of a vibrator according to the present invention.

FIG. 2 is a sectional view taken along line A-A in FIG. 1;

FIG. 3 is a vertical cross-sectional view showing a conventional vibrator.

[Explanation of symbols]

1, 2...metal block 3 to 6...Piezoelectric element plate 7-10...electrode plate 7a to 10a...Terminal section 11...Bolt 12...Rotor 13...Output member 14...Bearing

Claims (1)

[Claims] Claim 1: Electromechanical energy conversion elements that generate vibrations in response to electrical signals supplied through interposed electrode plates are arranged in a stacked manner, and these plurality of electromechanical energy conversion elements are driven in A phase. It is divided into two parts, a group and a B-phase drive group, and is integrated by fastening the vibrating blocks disposed at both ends thereof so as to sandwich the electro-mechanical energy conversion element and the electrode plate with a fastening member, In a vibrator that vibrates by combining vibrations excited by the A-phase drive group and the B-phase drive group in the vibrator block, a position where each external power supply terminal part of the plurality of electrode plates is overlapped in the axial direction. A vibrator, characterized in that the external power supply terminal portion is located at a conjugate position of a vibration system vibrated by the A-phase drive group and a vibration system vibrated by the B-phase drive group.