Nippondenso Co., Ltd.

Denso Corporation

Kenzi Kato

Tomoo Kawase

Kazuhiko Miura

Yoshimi Yoshino

Takehiro Watarai

Tomoyuki Kanda

Satoshi Hayashi

Yoshinobu Takeuchi

Junichi Sato

A vibration-type angular velocity detector is for accurately correcting temperature-induced variations of an angular velocity signal without using a temperature sensor. A driving piezoelectric element, a detecting piezoelectric element and reference piezoelectric element are disposed on a vibration element. Using an output signal of the reference piezoelectric signal, a feedback control loop for applying driving voltage to the driving piezoelectric element is provided using an amplifier, a phase-shifting circuit, a rectifier, a reference voltage generator, a differential amplifier and a multiplier so as to vibrate the vibration element at a fixed amplitude. In addition, using an output signal of the detecting piezoelectric element at the time of vibrating the vibration element, an angular velocity signal is output. Here, the output voltage of the differential amplifier is a signal corresponding to the temperature of the vibration element. A correction signal is prepared by a correction signal preparing circuit using the differential amplifier output signal added to the angular velocity signal by a summer so that the temperature correction of the angular velocity signal is performed.

Vibration-type angular velocity detector having sensorless temperature

A frame body and a tuning fork-shaped vibratory element are made of a single crystalline silicon substrate. The vibratory element has arms extending parallel to each other. The respective sides of the frame body are located face to face with a predetermined distance from the arms. Thin portions are formed between thick portions located partially on the arms of the vibratory element. Piezo-resistant elements for detecting angular velocity are disposed on the thin portions. When electrostatic force is imposed between the sides of the frame body and the arms, the arms are excited to vibrate. At this time, when angular velocity is imposed, the arms vibrate in the direction crossing at right angles with the excited direction. The piezo-resistant elements detect vibration of the arms caused by the angular velocity with stabilized characteristics and higher sensitivity.

Angular velocity sensor apparatus

An angular velocity detector includes vibrator made of piezoelectric material and having a pair of arms. A pair of driving electrodes are attached to the arms in order to generate vibrations in the arms. A pair of detecting electrodes, which are attached to the arms, detect the vibrations of the arms. Therefore, the pair of driving electrodes can cause the arms to vibrate uniformly and stably, so that a S/N ratio of the angular velocity sensor can be improved.

Angular velocity sensor

A vibration-type angular-velocity sensor which can be reduced in size in the direction of the axis of the angular-velocity to be measured. A vibration body 11 comprises a pair of parallel driving plates 121 and 122 bent into a U-shape and extending in a Y direction, and a pair of detection plates 151 and 152 are so formed as to extend in mutually opposite directions in an X-axis direction by bending outwards the distal ends of the driving plates 121 and 122, respectively. The driving plates 121 and 122 are supported at a connecting plate 13 portion by a support member 14 in such a manner as to be capable of vibration. Piezoelectric devices 161 and 162 are bonded to the surfaces of the driving plates 121 and 122, respectively. When an A.C. voltage is applied, the driving plates are vibrated in mutually opposite directions. When a rotary angular-velocity, around the Z-axis of the sensor, generates a force in a Y-axis direction, due to the Coriolis effect, on the detection plates 151, 152, the Coriolis force is detected by piezoelectric devices 171 and 172. Accordingly, detection signals proportional to the angular-velocity are outputted from the detection piezoelectric devices 171 and 172.

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Okazaki, Japan

Kenzi Kato