Electrical generator or motor structure – Non-dynamoelectric – Piezoelectric elements and devices
Reexamination Certificate
2000-01-19
2002-05-07
Ramirez, Nestor (Department: 2834)
Electrical generator or motor structure
Non-dynamoelectric
Piezoelectric elements and devices
C310S323040
Reexamination Certificate
active
06384513
ABSTRACT:
TECHNICAL FIELD
The present invention relates to an ultrasonic motor which is structured for applying an electric signal to an electrode provided on polarized piezoelectric elements to thereby cause a vibration wave on an ultrasonic stator fixed with the piezoelectric element, so that an ultrasonic rotor is driven while in pressure contact with the ultrasonic stator. More particularly, the invention is concerned with a structure of an ultrasonic motor lead board provided for applying an electric signal to piezoelectric elements of the ultrasonic motor.
Also, the invention relates to a method for manufacturing an ultrasonic motor including an ultrasonic motor lead board provided for applying an electric signal to piezoelectric elements.
BACKGROUND ART
Referring to FIG.
11
and
FIG. 12
, an ultrasonic motor of the related art includes an ultrasonic motor
910
provided with an ultrasonic stator
922
, an ultrasonic motor support member
924
, an ultrasonic motor shaft
932
, an ultrasonic rotor
934
and an ultrasonic motor lead board
940
.
The ultrasonic motor support member
924
has a through-hole
924
a
fixed with the ultrasonic motor shaft
932
by passing the ultrasonic motor shaft
932
through the through-hole
924
a.
The ultrasonic stator
922
has a center hole
922
a,
an ultrasonic stator main body
922
b
and projections (comb teeth)
922
c
for displacement magnification. The displacement-magnifying projections (comb teeth)
922
c
are provided in a surface of the ultrasonic stator main body
922
b.
A polarized piezoelectric element
950
is fixed on an underside of the ultrasonic stator main body
922
b.
The ultrasonic stator
922
is passed at its center hole
922
a
over the ultrasonic motor shaft
932
and firmly fixed to the ultrasonic motor shaft
932
. The ultrasonic stator
922
is firmly fixed on the ultrasonic motor shaft
932
such that the center hole
922
a
has an end face at an outer peripheral portion thereof that is contacted with the ultrasonic motor shaft
932
.
The ultrasonic motor lead board
940
is provided to apply an electric signal to an electrode provided on the piezoelectric element
950
. The ultrasonic motor lead board
940
is arranged between the ultrasonic stator main body
922
b
and the ultrasonic motor support member
924
. The ultrasonic motor lead board
940
is neither fixed to the ultrasonic stator main body
922
b
nor the ultrasonic motor support member
924
. The ultrasonic motor lead board
940
has conductor patterns
940
a,
940
b
having tips respectively soldered (respectively shown at
952
a,
952
b
) to electrodes
950
a,
950
b
of the piezoelectric element
950
.
The ultrasonic rotor
934
includes an ultrasonic rotor lower member
934
a,
an ultrasonic rotor upper member
934
b,
a rotation member
934
c,
a set screw
934
d
and a spring contact member
934
e.
The ultrasonic rotor
934
is provided rotatable relative to the ultrasonic motor shaft
932
such that the lower member
934
a
at its underside contacts top surfaces of projections
922
c
of the ultrasonic stator
922
.
A pressurizing spring
960
contacts with a summit of the spring contact member
934
e.
The elastic force of the pressurizing spring
960
puts the ultrasonic rotor
934
in pressure contact with the ultrasonic stator
922
.
An ultrasonic motor drive circuit (not shown) generates an electric signal to drive the ultrasonic motor
910
. The electric signal is input to the piezoelectric element
950
by way of the conductor patterns
940
a
and
940
b
on the ultrasonic motor lead board
940
. Based on the electric signal, oscillation waves are produced on the ultrasonic stator
922
fixed with the piezoelectric element
950
. Due to the oscillation wave, the ultrasonic rotor
934
rotates which is contacted in a pressurized state with the ultrasonic stator
922
.
In the related art ultrasonic motor, however, the ultrasonic motor lead board is arranged between the ultrasonic stator and the ultrasonic motor support member but secured neither to the ultrasonic stator nor the ultrasonic motor support member. Meanwhile, a vertical gap exists between the ultrasonic motor lead board and the ultrasonic stator. Also, there is a vertical gap between the ultrasonic motor lead board and the ultrasonic motor support member.
As a consequence, the ultrasonic motor lead board might freely move in the vertical direction between the ultrasonic stator and the ultrasonic motor support member. As a result, there has been a concern that the conductor patterns on the ultrasonic motor lead board may be stripped off the ultrasonic motor lead board main body thus resulting in the occurrence of electric disconnection.
Furthermore, in the related art ultrasonic motor the ultrasonic stator has been secured onto the ultrasonic motor shaft in a state wherein the conductor patterns on the ultrasonic motor lead board are connected to the ultrasonic stator. Consequently, there has been difficulty in firmly fixing the ultrasonic stator to the ultrasonic motor shaft. Meanwhile, there has been a concern that in the fixing process the conductor patterns on the ultrasonic motor lead board may be stripped off the ultrasonic motor lead board main body thus resulting in the occurrence of electric disconnection.
It is therefore an object of the present invention to provide, in order to solve the above problems, an ultrasonic motor which is free from the concern that the conductor patterns on an ultrasonic motor lead board may be stripped off the ultrasonic motor lead board main body, and a method for manufacturing such an ultrasonic motor.
It is another object of the invention to provide an ultrasonic motor which is easy to assemble and manufacture.
DISCLOSURE OF INVENTION
In order to solve the above problems, the present invention is structured such that, in an ultrasonic motor having a structure in which an electric signal is applied to an electrode provided on a polarized piezoelectric element to cause a vibration wave on an ultrasonic stator fixed with the piezoelectric element, and an ultrasonic rotor is driven that contacts in a pressurized state with the ultrasonic stator, a combination is provided comprising: an ultrasonic motor shaft for supporting an ultrasonic stator and an ultrasonic motor support member; an ultrasonic motor support member firmly fixed on the ultrasonic motor shaft; an ultrasonic stator fixed with a piezoelectric element having an electrode and being polarization treated, and fixed on the ultrasonic motor shaft; an ultrasonic motor lead board having a conductor pattern firmly fixed to the ultrasonic motor support member; an ultrasonic rotor rotatably provided on the ultrasonic motor shaft and contacted with the ultrasonic stator; a pressurizing spring for pressurizing the ultrasonic stator and the ultrasonic rotor; wherein the conductor pattern of the ultrasonic motor lead board is electrically connected to the electrode of the piezoelectric element.
This structure can eliminate the concern that the conductor pattern of the ultrasonic motor lead board may be stripped off an ultrasonic motor lead board main body, or reduce this concern.
Also, it is preferred that the ultrasonic motor support member has a first through-hole to pass through the ultrasonic motor shaft and a second through-hole to pass through the conductor pattern of the ultrasonic motor lead board, the ultrasonic motor support member being firmly fixed on the ultrasonic motor shaft in such a state that the ultrasonic motor shaft is passed through the first through-hole of the ultrasonic motor support member, and the conductor pattern of the ultrasonic motor lead board, in a state passing through the second through-hole, being firmly fixed to the electrode of the piezoelectric element in the ultrasonic motor of the present invention.
Also, it is preferred that the ultrasonic stator has a cylindrical portion (
122
d
) having a center hole, and that the ultrasonic stator is firmly fixed on the ultrasonic motor shaft in such a state that the cylindrical portion at one end face contac
Oono Takashi
Satodate Takayuki
Adams & Wilks
Medley Peter
Ramirez Nestor
Seiko Instruments Inc.
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