Electrical generator or motor structure – Non-dynamoelectric – Piezoelectric elements and devices
Reexamination Certificate
1996-12-30
2001-04-17
Budd, Mark O. (Department: 2834)
Electrical generator or motor structure
Non-dynamoelectric
Piezoelectric elements and devices
Reexamination Certificate
active
06218767
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a vibration device which uses a vibration of a vibration member to generate vibration force.
2. Description of the Related Art
In a vibration device, power is supplied to a vibration member while the vibration member is in pressure contact with a contact member, to generate vibration force in the vibration member, so that the vibration member and the contact member are relatively moved.
In this case, as a method of connecting a power supply terminal of a conventional vibration member, as disclosed in Japanese Examined Utility Model Publication No. 6-28954, one method is to directly bond a lead line, a flexible printed board, or the like on the vibration member with solder.
However, in the above embodiment, since the vibration m ember directly receives heat from the solder, the piezoelectric characteristics of the vibration member are degraded, and satisfactory driving characteristics of a vibration device cannot be obtained.
In a method of directly bonding a power supply terminal to a vibration member with solder, the power supply terminal may be disconnected from the solder, or the solder may peel together with an electrode layer of the vibration member. As a result, the power supply terminal may not be in contact with the vibration member. In addition, when solder is bonded at a position where vibration displacement occurs, a desired vibration mode may be blocked, and sufficient driving force may not be obtained.
Furthermore, both soldering on the vibration member, and providing leads and connections for the terminal for the vibration member to an external drive circuit are cumbersome operations. For this reason, productivity is considerably degraded.
In some vibration devices using a vibration wave, a vibration member having a rectangular shape is vibrated to linearly vibrate a moving member (contact member) which is in contact with the vibration member. Such a vibration device is arranged as shown in
FIG. 27
, for example. In
FIG. 27
, reference numeral
271
denotes an elastic member, and reference numeral
272
denotes a piezoelectric element for exciting a vibration of the elastic member
271
. The above vibration member is constituted by the elastic member
271
and the piezoelectric element
272
.
Reference numerals
272
a
,
272
b
, and
272
c
denote electrode films for applying a voltage signal having a specific frequency to the piezoelectric element
272
. Reference numeral
275
denotes a pressure spring for pressing the mobile member
274
against the elastic member
271
with appropriate force, and reference numeral
277
denotes a bearing for reducing an abrasion resistance between the pressure spring
275
and the mobile member
274
.
In the vibration device arranged as described above, when a voltage control circuit applies voltages (indicated by sin and cos in
FIG. 27
) having specific frequencies and phases which are different by 90° to the electrode films
272
a
and
272
b
, the piezoelectric element
272
repeatedly extends and contracts at these frequencies. The extension and contraction of the piezoelectric element
272
excites a longitudinal vibration (e.g., primary mode vibration) and a bending vibration (e.g., quaternary mode vibration) in the elastic member
271
. These vibrations synthesize a standing wave for moving the mobile member
274
. Due to the synthesized standing wave, material points on the surface of the elastic member
271
elliptically move in the same direction. For this reason, when the mobile member
274
is brought into pressure contact with the elastic member
271
, the mobile member
274
is driven by friction between the elastic member
271
and the mobile member
274
in the direction indicated by the arrow in FIG.
27
. Movement extraction members
273
a
and
273
b
amplify the elliptical movement and transmit it to the mobile member
274
arranged on the elastic member
271
.
As unit structures of a driving device operate on the basis of the same principle as described above, for example, a structure proposed in Japanese Unexamined Patent Publication No. 2-228266 (see FIG.
28
(
b
)) and a structure proposed in Japanese Unexamined Patent Publication No. 6-261568 (see FIG.
28
(
b
)) are known. In these unit structures, the vibration member
281
and the contact portion between the mobile member
284
and the vibration member
281
are covered with a case
286
.
However, in both cases shown in FIGS.
28
(
a
) and
28
(
b
), since the pressure spring
285
for pressing the mobile member
284
against the vibration member
281
is attached to the inside of the case
286
, a space for storing the pressure spring
285
must be formed inside the case
286
. For this reason, the case
286
tends to increase in size.
The space can be decreased in size by decreasing an amount of deformation by increasing the spring constant of the pressure spring
285
. However, when the spring constant is large, the pressing force greatly changes depending on the amount of deformation of the pressure spring
285
, and it is difficult to properly set the pressing force.
Also, a unit in which the pressure spring
285
is stored in the case
286
cannot be easily assembled.
SUMMARY OF THE INVENTION
According to one aspect of the Invention, a power supply member for supplying power to a vibration member is arranged to sandwich the vibration member, so that stable power supply can be performed without soldering.
Other aspects of the Invention will be apparent with reference to the following detailed description of the preferred embodiments.
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patent: 4720650 (1988-01-01), Hanamori
patent: 4857793 (1989-08-01), Okuno
patent: 4959580 (1990-09-01), Vishnevsky et al.
patent: 5036245 (1991-07-01), Ohnishi et al.
patent: 5039899 (1991-08-01), Yamaguchi
patent: 5066884 (1991-11-01), Takagi et al.
patent: 5101132 (1992-03-01), Yamaguchi
patent: 5105117 (1992-04-01), Yamaguchi
patent: 5136200 (1992-08-01), Takizawa et al.
patent: 5247220 (1993-09-01), Miyazawa et al.
patent: 5532540 (1996-07-01), Claeyssen et al.
patent: 5665918 (1997-09-01), Takano et al.
patent: 06-028954 (1994-03-01), None
Akada Hiroshi
Chigira Tatsuo
Takano Hironori
Yamamoto Hiroshi
Budd Mark O.
Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
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