Hitachi, Ltd.

Hitachi Engineering Service Co., Ltd.

Hitachi Material Engineering, Ltd.

Takao Yoneyama

Ichiya Sato

Tsuguaki Koga

Sanshiro Obara

Hisanori Okamura

Kanji Kawakami

Katsukuni Hisano

Hisao Okada

Tomoaki Inoue

Masanori Tanabe

Kazuo Ikeuchi

Hideo Uzuhashi

Satoshi Kokura

Soji Sasaki

Ichiya Satoh

Mareo Suto

Minoru Yanagibashi

Shigeru Inose

Yoshihisa Nomoto

Shigeru Takegami

Koichi Nakakubo

The features of the present invention are 1) to apply metallization on the bonding surface of a piezoelectric ceramic with a metal likely to react with the piezoelectric ceramic material, 2) when the piezoelectric ceramic material is soldered on the bonding surface, to apply metallization with a metal likely to react with the solder material, 3) to provide between the metallizing layers formed in 1) and 2) a metallizing layer including metal which prevents reaction between the metals and their diffusion, 4) to use a mounting member for the piezoelectric ceramic which has substantially the same thermal expansion coefficient as the piezoelectric ceramic in non-polarization condition and 5) to solder in the non-polarization condition and thereafter to polarize. As the result, a bonded type piezoelectric apparatus with a high reliability or with a broad application temperature range near from the absolute zero temperature to the Curie point of the piezoelectric element, and a method of manufacturing the same are provided.

Bonded type piezoelectric apparatus, method for manufacturing the same

Disclosed is a rotating machinery diagnosis system with an AE technique, which comprises: an AE sensor mounted on a rotary machine for sensing an acoustic signal of the rotary machine; envelope detector means for obtaining an envelope signal from the acoustic signal from the AE sensor; waveform-feature processor means for performing signal processing so as to detect a feature of waveform of an output waveform signal from the envelope detector means; feature decision means for judging whether the feature of waveform belongs to a continuous type or a burst type and/or to a rotation-synchronous type or a rotation-asynchronous type on the basis of an output signal from the waveform-feature processor means; and diagnostic output means for outputting and displaying an output signal from the feature decision means, whereby it is possible to perform judgement simultaneously as to a plurality of kinds of abnormality.

Rotating machinery diagnosis system with acoustic emission technique

A tablet type coordinate input apparatus comprises a flat medium for propagating a longitudinal elastic wave, longitudinal elastic wave detecting elements disposed on part of the end-adjacent side surfaces or of the front surface of the flat medium, a longitudinal elastic wave input member having an end portion terminating in a sharp-pointed end and brought into pressure engagement at that end with any desired position on the surface of the flat medium to radiate the longitudinal elastic wave from that end, an amplifier circuit amplifying electrical signals indicative of the elastic wave detected by the detecting elements, a comparator circuit comparing the signals amplified by the amplifier circuit with a predetermined threshold voltage thereby generating delay pulse signals corresponding to the propagation times of the longitudinal elastic wave, a counter circuit counting the lengths of time elapsed from the time of radiation of the longitudinal elastic wave toward the flat medium as a result of pressure engagement of the input member therewith to the time of generation of the delay pulse signals, and a computing circuit computing the coordinates on the basis of the time signals applied from the counter circuit.

Tablet type coordinate input apparatus using elastic wave

A method and apparatus for detecting metal wipe damages of plane bearings with the metal wipe generating an ultrasonic signal as an acoustic emission signal when it occurs. The ultrasonic signal has a periodic appearance therefore, the metal wipe damages, can be detected by monitoring the periodic nature of the ultrasonic signal. The ultrasonic signal is received by a transducer fixed to the plane bearing with the periodic nature of the received ultrasonic signal being computed by a processing unit so as to provide a output signal of the occurrence of a metal wipe when the received ultrasonic signal is periodic.

Method and apparatus for detecting metal wipe damages of plane bearing

A method and apparatus for detecting the occurrence of rubbing in a rotary machine, in which at least one acoustic sensor is mounted on at least the rotor part or the stator part of the rotary machine, and the output signal from the acoustic sensor is detected and then filtered to extract a frequency component having a frequency substantially equal to the rotational frequency of the rotary machine, so as to detect the occurrence of rubbing in the rotary machine as early as possible and also to locate the source of the rubbing. Even when the occurrence of abnormal metal-to-metal contact at a bearing of the rotary machine is detected, it is discriminated from rubbing so that the occurrence of the rubbing can be reliably detected.

Method and apparatus for detecting rubbing in a rotary machine

Temperature-rise detecting device and average beam current restricting device operable in response to the former device are provided in television receiver set. Temperature in the television receiver may be kept below a predetermined temperature by reducing the average beam current when the temperature in the television receiver set rises. This results in the lowering of the maximum rated temperature for the parts used in the fly-back transformer, the high voltage rectifier, etc.

Temperature-rise preventive apparatus for television receiver parts

Growing community of inventors

Katsuta, Japan

Takao Yoneyama