A sensor unit includes a pressure sensor, an acceleration sensor and a signal-processing circuit, which are disposed on the bottom surface of a lead to form a line in the longitudinal direction of the sensor unit. The pressure sensor and the acceleration sensor are disposed at respective symmetrical positions with respect to the center of the signal-processing circuit in the longitudinal direction of the sensor unit. Each of the pressure sensor and the acceleration sensor has substantially the same height dimension. The sensors, the signal-processing circuit and the lead are sealed with a molded body, in such a manner as to allow lead terminals of the lead to protrude outside the molded body. The signal-processing circuit is operable, based on a signal from the acceleration sensor, to control the ON/OFF action of the pressure sensor.
1. A sensor unit comprising:
a lead having edge portions formed as lead terminals serving as input/output terminals;
a plurality of physical-quantity sensors including a pressure sensor and an acceleration sensor, wherein each of said plurality of physical quantity sensors are disposed relative to said lead;
a signal-processing circuit disposed relative to said lead and adapted to process a signal from each of said physical-quantity sensors;
a molded body made of a plastic material, and formed to seal said lead, said physical-quantity sensors and said signal-processing circuit in such a manner as to allow said lead terminals to protrude outside said molded body, said molded body comprising a through-hole extending upwardly from a pressure receiving portion of the pressure sensor and allows fluid communication between the outside of the molded body and the pressure receiving portion; and
wherein said signal-processing circuit is operable, based on the signal from at least one of said plurality of physical-quantity sensors, to control the ON/OFF action of the remaining physical-quantity sensors.
2. The sensor unit according to claim 1 , wherein:
said pressure sensor, said acceleration sensor and said signal-processing circuit are disposed to form a line in the longitudinal direction of said sensor unit;
said pressure sensor and said acceleration sensor are disposed at respective symmetrical positions with respect to the center of said signal-processing circuit in the longitudinal direction of said sensor unit; and
each of said pressure sensor and said acceleration sensor has substantially the same height dimension.
3. The sensor unit according to claim 1 , further comprising a flexible resin interposed between a lower surface of said acceleration sensor and a surface of said molded body.
4. The sensor unit according to claim 1 , wherein said pressure-introducing passage includes a plurality of small-diameter channels.
5. The sensor unit according to claim 1 , wherein said molded body is integrally formed with a tubular portion extending continuously from the edge of the opening of said through-hole to the outside of said molded body and having substantially the same inner diameter as that of said through-hole.
6. The sensor unit according to claim 1 , wherein said plurality of physical-quantity sensors further include a rotational-angular-velocity sensor.
7. The sensor unit according to claim 1 , wherein:
each of said plurality of physical-quantity sensors has substantially the same height dimension; and
said molded body has a portion extending between each of said physical-quantity sensors and an outer surface of said molded body on the side of said physical quantity sensor, and another portion extending between said lead and an outer surface of said molded body on the side of said lead, each of said portions having substantially the same thickness dimension.
8. The sensor unit according to claim 1 , wherein said molded body have a portion covering the top-surface side of said lead and another portion covering the bottom-surface side of said lead, said portions being formed to have different tapered shapes from one another so as to allow the respective volumes of said portions to be substantially equalized.
9. The sensor unit according to claim 1 , wherein at least one of said plurality of physical-quantity sensors and said signal-processing circuit are disposed, respectively, on the top and bottom surfaces of said lead in such a manner as to sandwich said lead therebetween.
10. A sensor unit comprising:
a lead having edge portions formed as lead terminals serving as input/output terminals;
a plurality of physical-quantity sensors including an acceleration sensor and a rotational angular-velocity sensor, each of said plurality of physical quantity sensors disposed relative to said lead;
a signal-processing circuit disposed relative to said lead and adapted to process a signal from each of said physical-quantity sensors; and
a molded body made of a plastic material, and formed to seal said lead, said physical-quantity sensors and said signal-processing circuit in such a manner as to allow said lead terminals to protrude outside said molded body, wherein said signal-processing circuit is operable, based on the signal from at least one of said plurality of physical-quantity sensors, to control the ON/OFF action of the remaining physical-quantity sensors.
11. A sensor unit comprising:
a lead having edge portions formed as lead terminals serving as input/output terminals;
a plurality of physical-quantity sensors each disposed relative to said lead and adapted to measure a physical quantity;
a signal-processing circuit disposed relative to said lead and adapted to process a signal from each of said physical-quantity sensors;
a molded body made of a plastic material, and formed to seal said lead, said physical-quantity sensors and said signal-processing circuit in such a manner as to allow said lead terminals to protrude outside said molded body, wherein said signal-processing circuit is operable, based on the signal from at least one of said plurality of physical-quantity sensors, to control the ON/OFF action of the remaining physical-quantity sensors, and wherein each of said plurality of physical-quantity sensors has substantially the same height dimension; and
said molded body has a portion extending between each of said physical-quantity sensors and an outer surface of said molded body on the side of said physical quantity sensor, and another portion extending between said lead and an outer surface of said molded body on the side of said lead, each of said portions having substantially the same thickness dimension.
12. A sensor unit comprising:
a lead having edge portions formed as lead terminals serving as input/output terminals;
a plurality of physical-quantity sensors each disposed relative to said lead and adapted to measure a physical quantity;
a signal-processing circuit disposed relative to said lead and adapted to process a signal from each of said physical-quantity sensors; and
a molded body made of a plastic material, and formed to seal said lead, said physical-quantity sensors and said signal-processing circuit in such a manner as to allow said lead terminals to protrude outside said molded body, wherein said signal-processing circuit is operable, based on the signal from at least one of said plurality of physical-quantity sensors, to control the ON/OFF action of the remaining physical-quantity sensors, and wherein said molded body has a portion covering the top-surface side of said lead and another portion covering the bottom-surface side of said lead, said portions being formed to have different tapered shapes from one another so as to allow the respective volumes of said portions to be substantially equalized.
13. A sensor unit comprising:
a lead having edge portions formed as lead terminals serving as input/output terminals;
a plurality of physical-quantity sensors each disposed relative to said lead and adapted to measure a physical quantity;
a signal-processing circuit disposed relative to said lead and adapted to process a signal from each of said physical-quantity sensors; and
a molded body made of a plastic material, and formed to seal said lead, said physical-quantity sensors and said signal-processing circuit in such a manner as to allow said lead terminals to protrude outside said molded body, wherein said signal-processing circuit is operable, based on the signal from at least one of said plurality of physical-quantity sensors, to control the ON/OFF action of the remaining physical-quantity sensors, and wherein at least one of said plurality of physical-quantity sensors and said signal-processing circuit are disposed, respectively, on the top and bottom surfaces of said lead in such a manner as to sandwich said lead therebetween.