Oscillation gyroscope

Details Oscillation gyroscope Oscillation gyroscope

1995-12-01

2001-06-05

Budd, Mark O. (Department: 2834)

Electrical generator or motor structure

Non-dynamoelectric

Piezoelectric elements and devices

C310S321000, C310S348000, C310S353000

Reexamination Certificate

active

06242848

ABSTRACT:

BACKGROUND OF THE INVENTION
The present invention relates to an oscillation gyroscope, and in particular to an oscillation gyroscope which is used in navigation systems, shaking prevention systems and the like, for example.
FIG. 9
is a cutaway perspective view showing an example of a conventional oscillation gyroscope
100
which is the background of this invention, and
FIG. 10
is a circuit drawing of the oscillation gyroscope
100
. This oscillation gyroscope
100
includes an oscillator
102
. The oscillator
102
includes a cross-sectional triangular oscillating body
103
, and piezoelectric elements
104
a,
104
b
and
104
c
which are formed in the three side surfaces of the oscillating body
103
, as shown in FIG.
10
. Each of these piezoelectric elements
104
a
to
104
c
form electrodes on both surfaces of a piezo ceramics for example.
As shown in
FIG. 9
, the oscillator
102
has support members
105
a
and
105
b
which are substantially C-shaped and are each attached to ridge line portions in the vicinity of two node points. The end portions of these support members
105
a
and
105
b
are respectively fixed to a flat plate shaped attachment boards
106
a
and
106
b.
The attachment boards
106
a
and
106
b
are separated into two so as not to suppress the vibration of the oscillator
102
. Also, a plurality of terminal electrodes (not shown in the drawing) are formed on the attachment board
106
a,
and these are respectively electrically connected with the electrodes of the piezoelectric elements
104
a
to
104
c
of the oscillator
102
via lead wires. Further, on the attachment boards
106
a
and
106
b,
substantially C-shaped protective plates
110
a
and
110
b
are fixed substantially perpendicular to the main surfaces of the attachment boards
106
a
and
106
b
by attaching them by soldering or welding. The protective plates
110
a
and
110
b
have respective predetermined gaps from the lower surface of the oscillator
102
, which are for the purpose of protecting the support members
105
a
and
105
b
so that the oscillator
102
is not displaced more than necessary when shocks are imposed thereon.
The attachment boards
106
a
and
106
b
are each fixed to one main surface of a cross-sectional substantially C-shaped metal frame
107
. The metal frame
107
is fixed to one main surface of a flat plate-shaped circuit board
108
. An oscillator circuit
113
comprising chip components such as an operational amplifier, resistors, capacitors, etc., a variable resistor unit etc., and a detection circuit
114
, and the like are mounted on the other main surface of the circuit board
108
. Also, the attachment board
106
a
and the circuit board
108
are rigidly coupled to each other by rigid metal terminals
109
a
to
109
d
comprising metal plates which are substantially L-shaped and have predetermined widths and lengths. The end portions of each of the rigid metal terminals
109
a
to
109
d
are each rigidly fixed to the attachment board
106
a
and the circuit board
108
, respectively. Also, the terminal electrodes on the attachment boards
106
a
and
106
b
are connected to the terminal electrodes (not shown in the drawing) of the circuit board
108
via the rigid metal terminals
109
a
to
109
d,
respectively. Further, as shown in
FIG. 9
, the oscillator
102
, the metal frame
107
, the rigid metal terminals
109
a
to
109
d,
etc. are all housed in a box-shaped case
112
. In addition, both ends in the length direction of the oscillator
102
are protected by the inside surface of the case
112
so that the oscillator
102
is not displaced more than necessary when shocks are imposed thereon.
As shown in
FIG. 10
, one piezoelectric element
104
c
of the oscillator
102
is electrically connected to an input terminal of the oscillator circuit
113
, and an output terminal of the oscillator circuit
113
is electrically connected to the other two piezoelectric elements
104
a
and
104
b,
respectively. As a result, the oscillator
102
is driven by self-excitation. Also, the two piezoelectric elements
104
a
and
104
b
are each electrically connected to input terminals of the detection circuit
114
comprising a differential amplifier, for example. Accordingly, rotation angle velocity is detected by the output circuit of the detection circuit
114
.
However, if the spaces between the oscillator
102
and the case
112
surrounding it and the protective plates
110
a
and
110
b
is too short, the vibration of the oscillator
102
is hindered, and if the spaces are too long, the oscillator
102
is greatly displaced when a shock is imposed causing the support members
105
a
and
105
b
to be plastically deformed. As a result, there is a possibility that the oscillation gyroscope
100
may cease to function. Therefore, these spaces must be precisely formed to a length which does not hinder the vibration of the oscillator
102
and which does not cause plastic deformation of the support members
105
a
and
105
b.
However, because in the oscillation gyroscope
100
of the prior art, the protective plates
110
a
and
110
b
are affixed by soldering or the like, the space between the protective plates
110
a
and
110
b
and the oscillator
102
may fluctuate readily depending on the amount of solder or the like. Further, the space between the protective plates
110
a
and
110
b
and the oscillator
102
may fluctuate readily in the period until the solder or the like hardens.
In addition, because the metal terminals
109
a
to
109
d
are provided at only one location in the lengthwise direction of the oscillator
102
, when the case
112
is attached, the space between the case
112
and the oscillator
102
may vary readily at both sides in the lengthwise direction of the oscillator
102
. Further, in the prior art oscillator gyroscope
100
, the upper end in the height direction of the oscillator
102
is protected by the case
112
, but it is difficult to form the space between the case
112
and the oscillator
102
precisely.
In this way, in the oscillation gyroscope
100
of the prior art, because it is difficult to precisely form the space between the oscillator
102
and the periphery thereof, it is also difficult to improve the shock resistance thereof. Also, in the oscillation gyroscope
100
shown in
FIG. 9
, displacement in both diagonal upward directions of the oscillator
102
cannot be sufficiently prevented, and when a large shock is imposed in these directions, the shock resistance has not been found to be sufficient.
SUMMARY OF THE INVENTION
Given the above, the main object of this invention is to provide an oscillation gyroscope having excellent shock resistance.
The oscillation gyroscope of this invention is an oscillation gyroscope comprising an oscillator, support members for supporting the oscillator close to a node point thereof, and protective members disposed surrounding a periphery of the oscillator, for preventing displacement of the oscillator so that the support members do not cause plastic deformation. Further, it further comprises attachment boards for supporting the oscillator and the support members, and the protective members preferably include members formed by bending part of the attachment bases in the direction of the oscillator. Also, the protective members preferably include members having notches corresponding to a shape of the oscillator.
Since the periphery of the oscillator is surrounded and protected by the protective members, even when a large shock is imposed on the oscillation gyroscope, the oscillator is not displaced more than a predetermined limited amount and plastic deformation of the support members is prevented. Also, where members formed by bending part of the attachment board in the direction of the oscillator are included in the protective members, the precision of the gap between these members and the oscillator can be improved. Further, where members having a notch corresponding to the shape of the oscillator are included in the protective members, the gap between th

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