Measuring and testing – Speed – velocity – or acceleration – Angular rate using gyroscopic or coriolis effect
Reexamination Certificate
1999-02-01
2001-03-13
Chapman, John E. (Department: 2856)
Measuring and testing
Speed, velocity, or acceleration
Angular rate using gyroscopic or coriolis effect
C073S493000
Reexamination Certificate
active
06199429
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a vibrating gyroscope to be incorporated into an angular speed sensing device included in a navigation system for an automobile.
2. Description of the Related Art
Referring to
FIG. 22
, a conventional vibrating gyroscope for measuring angular velocity has a case
221
, pins
222
, sensor support plate
223
provided with recesses
225
, vibration isolators
224
each having a neck
226
, provided with a through hole
227
and fitted in the recess
225
of the sensor support plate
223
, a tuning fork unit
228
serving as a sensor, collars
229
each provided with a through hole
230
, a wiring board
231
provided with through holes
232
, a flexible flat cable
233
, a lid
234
, and terminals
235
.
In this vibrating gyroscope, the sensor support plate
223
of a large mass supporting the sensor, i.e., the tuning fork unit
228
, is supported on the four vibration isolators
224
.
Since the sensor is attached to the sensor support plate
223
of a large mass, the sensor is unable to operate in a high response speed when the sensor support plate
223
is rotated at a high angular velocity. Consequently, the response of the sensor is delayed, and the operation of the sensor is unable to follow the change of the direction of angular velocity if the direction of angular velocity is reversed suddenly and, in some cases, the sensor is unable to provide an accurate output. The large sensor support plate
223
is heavy and the vibrating gyroscope has a complicated construction.
SUMMARY OF THE INVENTION
It is a first object of the present invention to provide a vibrating gyroscope having a simple construction, and employing a member of a small mass to be held by an elastic vibration isolator to reduce the effect of inertial force on a vibrator in order that the vibrator is able to respond at a high response speed to the quick change of angular velocity.
A second object of the present invention is to provide a vibrating gyroscope provided with a vibrator having a base part, and wiring lines connected to the base part of the vibrator by holding the base part of the vibrator between a plurality of elastic members. Since the wiring lines are connected to the base part of the vibrator by holding the base part of the vibrator between the plurality of elastic members, lead wires and such are not damaged when assembling the vibrating gyroscope.
A third object of the present invention is to provide a vibrating gyroscope having a first elastic member, a vibrator and a second elastic member placed in that order when assembling the vibrating gyroscope and capable of being easily assembled.
A fourth object of the present invention is to provide a vibrating gyroscope capable of suppressing the variation of the characteristic of a vibrator due to the inclination of the vibrator.
A fifth object of the present invention is to provide a vibrating gyroscope capable of easily assembled.
A sixth object of the present invention is to provide a vibrating gyroscope having elastic members capable of being uniformly distorted to reduce the variation of the characteristic of a vibrator.
A seventh object of the present invention is to provide a vibrating gyroscope employing elastic members capable of being easily held by lugs on a wiring board.
An eighth object of the present invention is to provide a vibrating gyroscope employing a vibrator holding case provided with retaining member for retaining an elastic member therein, and capable of preventing the elastic member from falling off the vibrator holding case even if an undesired force acts on the vibrator holding case.
A ninth object of the present invention is to provide a lightweight, inexpensive vibrating gyroscope employing an elastic vibration isolator made of silicone rubber.
According to a first aspect of the present invention, a vibrating gyroscope comprises a vibrator having a base part and provided with cantilever vibrating arms having vibrating free end parts, elastic vibration isolator put on the base part of the vibrator, and a wiring board supporting the elastic vibration isolator. Since the mass of the vibrator held by the elastic vibration isolator is small, the vibrator is scarcely subject to inertial force and is able to respond to the quick change of angular velocity at a high response speed, and the vibrating gyroscope is simple in construction.
Preferably, the vibrating gyroscope further comprises a vibrator holding case consisting of first and second holding members, the elastic vibration isolator has a plurality of vibration isolating members to be pressed against the opposite surfaces of the base part of the vibrator, respectively, to hold the base part of the vibrator therebetween, the elastic vibration isolator is interposed and compressed between the first and the second holding members, and the vibrator holding case is attached to the wiring board. Since the base part of the vibrator is held between the plurality of vibration isolating members, the joints of the electrodes formed on the base part of the vibrator, and lead wires and wiring lines of a flexible wiring board are not broken when assembling the vibrator and the elastic vibration isolator. If the elastic vibration isolator is provided with a hole and the base part of the vibrator is pressed in the hole to assemble the elastic vibration isolator and the vibrator, the joints of the electrodes, and the lead wires and the wiring lines may possibly caught by the elastic vibration isolator and broken.
Preferably, the elastic vibration isolator has a first elastic member having a hollow, and a second elastic member pressed against the base part of the vibrator fitted in the hollow of the first elastic member, and the base part of the vibrator is fitted in the hollow and is held between the first and the second elastic member. The vibrator and the elastic vibration isolator can easily be assembled simply by placing the base part of the vibrator in the hollow of the first elastic member, and putting the second elastic member on the base part of the vibrator.
Preferably, the base part of the vibrator has the shape of a plate, and the elastic members are pressed against the flat surfaces of the plate-shaped base part of the vibrator substantially perpendicularly to the surfaces of the base part by the vibrator holding case. Since the elastic members are pressed against the flat surfaces of the plate-shaped base part of the vibrator substantially perpendicularly to the surfaces of the base part, i.e., in directions along the thickness, by the vibrator holding case, the elastic members are hardly twisted and the vibrator is hardly tilted and hence the change of the sensing characteristic of the vibrator can be suppressed. If the elastic members are pressed in directions other than the directions along the thickness, the elastic members may be twisted and the vibrator may be tilted. Since the vibrator is tilted indefinitely if the elastic members are twisted, the sensing characteristic of the vibrator changes indefinitely.
Preferably, the vibrator holding case has a first holding member of a metal having at least a flat bottom wall and opposite side walls continuous with the flat bottom wall, and a plate-shaped second holding member, the first and the second holding member are pressed against the elastic members, respectively, at least one of the side walls of the first holding member is provided with a fastening lug, the elastic members and the base part of the vibrator are disposed between the side walls of the first holding member so that the surfaces of the base part and the flat surface of the bottom wall of the first holding member are substantially parallel to each other, and the fastening lug is fixed by crimping to the second holding member disposed with its plate-shaped part facing toward the flat bottom wall of the first holding member. Since the elastic members are compressed between the bottom wan of the first holding member and the second holding member, the elastic members can easi
Alps Electric Co. ,Ltd.
Brinks Hofer Gilson & Lione
Chapman John E.
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