Pressure sensor having a diaphragm having a pressure-receiving portion receiving a pressure and a thick portion adjacent to the pressure-receiving portion

1. A pressure sensor, comprising:

a diaphragm having two pressure-receiving portions receiving a pressure and a thick portion adjacent to the pressure-receiving portions;

a pressure sensitive element having a first and a second ends facing each other, wherein the pressure sensitive element extends in a direction intersecting the thick portion and the first end of the pressure sensitive element is bonded to a pressure-receiving surface of the pressure-receiving portions;

a central portion of a portion at which the pressure-receiving portions and the first end are bonded is positioned at a side closer to the second end of the pressure sensitive element than a center of the pressure-receiving portions;

a supporting portion including a supporting frame portion provided at a periphery of the two pressure-receiving portions; and

a bending-restraining portion serving as the thick portion disposed between the two pressure-receiving portions,

wherein the pressure sensitive element is disposed to step over the bending-restraining portion and is bonded to each of the pressure-receiving portions with the respective first and second ends.

2. The pressure sensor according to claim 1 , further comprising a cover to cover a surface having the pressure sensitive element of the diaphragm, the cover being fixed to the supporting frame portion so as to air-tightly seal an internal space formed between the diaphragm and the cover.

3. The pressure sensor according to claim 1 further comprising an oscillation circuit coupled to the pressure sensitive element and a frequency measuring and calculating unit coupled to the oscillation circuit.

4. A pressure sensor, comprising:

a diaphragm having pressure-receiving portions receiving a pressure and a thick portion adjacent to the pressure-receiving portions;

a pressure sensitive element having first and second ends facing each other, wherein the pressure sensitive element extends in a direction intersecting the thick portion and the first end of the pressure sensitive element is bonded to a pressure-receiving surface of the pressure-receiving portions;

a central portion of a portion at which the pressure-receiving portions and the first end are bonded is positioned at a side closer to the second end of the pressure sensitive element than a center of the pressure-receiving portions;

wherein the diaphragm includes:

a supporting frame portion formed in a frame shape;

first and second bending-restraining portions serving as the thick portion protruding toward an inside of the supporting frame portion from the supporting frame portion so as to face each other; and

the pressure-receiving portions are each disposed to a first region surrounded by the supporting frame portion and the first and second bending-restraining portions, and a second region surrounded by the supporting frame portion and the first and second bending-restraining portions, and

wherein the pressure sensitive element is disposed between the first and second bending-restraining portions so as to pass through therebetween, and the first end is bonded to the first region while the second end is bonded to the second region.

5. The pressure sensor according to claim 4 , further comprising a cover to cover a surface having the pressure sensitive element of the diaphragm, the cover being fixed to the supporting frame portion so as to air-tightly seal an internal space formed between the diaphragm and the cover.

6. The pressure sensor according to claim 4 , further comprising an oscillation circuit coupled to the pressure sensitive element, and a frequency measuring and calculating unit coupled to the oscillation circuit.

7. A pressure sensor, comprising:

a diaphragm having a pressure-receiving portion receiving a pressure and a thick portion adjacent to the pressure-receiving portion;

a pressure sensitive element having first and second ends facing each other, wherein the pressure sensitive element extends in a direction intersecting the thick portion and the first end of the pressure sensitive element is bonded to a pressure-receiving surface of the pressure-receiving portion;

a central portion of a portion at which the pressure-receiving portion and the first end are bonded is positioned at a side closer to the second end of the pressure sensitive element than a center of the pressure-receiving portion;

a supporting portion of the diaphragm serves as a thick portion provided at a periphery of the pressure-receiving portion, wherein the first end of the pressure sensitive element is bonded to the pressure-receiving portion, and at least a part of a portion excluding the first end is provided to the supporting portion to face each other,

wherein a distance a and a distance c satisfy a relation of c>a>0 where the distance a is a distance between a first edge of the first end and a first edge line of the supporting portion, the first edge facing the first edge line and being positioned toward an inside of the pressure sensitive element while the distance c is a distance between a second edge of the first end and a second edge line of the pressure-receiving portion, the second edge facing the second edge line and being provided in a direction intersecting the first edge.

8. The pressure sensor according to claim 7 , further comprising a cover to cover a surface having the pressure sensitive element of the diaphragm, the cover being fixed to the supporting frame portion so as to air-tightly seal an internal space formed between the diaphragm and the cover.

9. The pressure sensor according to claim 7 further comprising an oscillation circuit coupled to the pressure sensitive element and a frequency measuring and calculating unit coupled to the oscillation circuit.