What is claimed is:
1. A high frequency piezoelectric resonator, the piezoelectric resonator including a piezoelectric plate having disposed on its main surfaces, respectively, mutually opposing main electrodes for the excitation, a pair of second electrodes being each disposed surrounding the peripheral edge of its corresponding main electrode with a gap in between, wherein:
the material of the main electrode and the material of the second electrode are different from each other.
2. A high frequency piezoelectric resonator according to claim 1, wherein the density of the material of the second electrode is made lower than that of the main electrode; and relevant values of the main electrode, second electrode, and gap are set so that an anti-symmetric 0th mode does not become an trapped mode.
3. A high frequency piezoelectric resonator according to claim 1 or 2, wherein the piezoelectric plate is made a piezoelectric plate having formed therein a recess.
4. A high frequency piezoelectric resonator according to claims 1 to 3, wherein the configuration of the main electrode is made elliptic.
5. A high frequency piezoelectric resonator including a piezoelectric plate, one main surface of the piezoelectric plate being recessed to thereby form a thin portion therein, the main surface opposing the recess corresponding to the thin portion having formed thereon at its central portion a convex portion, the convex portion having formed thereon a main electrode for the excitation, a lead electrode being extended from the main electrode toward an edge of the plate, a second electrode being so provided as to surround the main electrode and the lead electrode with a gap in between, the piezoelectric plate having applied on a recess side thereof an entire electrode.
6. A high frequency piezoelectric resonator according to claim 5, wherein the convex portion is made elliptic.
7. A high frequency piezoelectric resonator according to claims 1 to 6, wherein the second electrode is divided into a plurality of portions; and adjustment of frequency is performed of these electrode portions.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A pressure regulating valve, comprising:
a case that includes a primary chamber and a secondary chamber;
a valve moving member that includes a piston and a valve element, wherein:
the valve moving member moves in such a manner as to cause communication or block communication between the primary chamber and the secondary chamber within the case, and
one end of the piston faces the secondary chamber and the other end faces a reference pressure chamber;
a plurality of seal members arranged between said case and said valve moving member, wherein:
said plurality of seal members are made of different materials, and
said plurality of seal members are arranged between a side surface of said piston and an inner wall of said case; and
communicating means for causing a space and said reference pressure chamber to communicate, wherein:
the space is defined by said side surface of said piston, said inner wall of said case and said plurality of seal members,
the communicating means is formed in a body of the case, and
the communicating means is configured to connect the space and the reference pressure chamber such that a pressure of the space is regulated when the piston moves.
2. The pressure regulating valve according to claim 1, wherein the communicating means is formed at an inner wall surface of the body of the case at a location of a first seal member of the plurality of seal members on a side of said reference pressure chamber.
3. The pressure regulating valve according to claim 1, wherein the communicating means is positioned in the body of the case such that the communication means and a first seal member of the plurality of seal members on a side of said reference pressure chamber do not overlap when the piston moves.
4. The pressure regulating valve according to claim 1, wherein materials for said plurality of seal members have different resistances to sliding.
5. The pressure regulating valve according to claim 1, wherein said plurality of seal members includes a ring-type seal at least provided between the side surface of said piston and the inner wall of said case and a ring-type damper that is configured to attenuate an extent of movement of said valve moving member.
6. The pressure regulating valve according to claim 1, wherein a first seal member of the plurality of seal members positioned at a side of the secondary chamber has a lower resistance to sliding than a second seal member of the plurality of seal members on a side of said reference pressure chamber.
7. The pressure regulating valve according to claim 1, wherein a first seal member of the plurality of seal members positioned at a side of the secondary chamber seals fluid to a greater extent than a second seal member of the plurality of seal members on a side of said reference pressure chamber.
8. The pressure regulating valve according to claim 1, wherein a first seal member of the plurality of seal members positioned on a side of said reference pressure chamber is configured to attenuate a moving force of said valve moving member to a greater extent than a second seal member of the plurality of seal members on a side of said secondary chamber.
9. The pressure regulating valve according to claim 1, wherein said plurality of seal members is constituted by at least two ring-type seals for sealing fluid, with one ring-type seal having a relatively higher resistance to sliding than the other ring-type seal.
10. The pressure regulating valve according to claim 1, wherein one of said plurality of seal members is a ring-type damper that is configured to attenuate an extent of movement of said valve moving member, with the ring-type damper being located at at least one of between said inner wall of said case and said valve element and between said inner wall of said case and said piston.
11. The pressure regulating valve according to claim 5, wherein said valve moving member is arranged with first and second urging means on either side within said case, with said ring-type damper being located at at least one of between said case and said first urging means, between said first urging means and said valve element, between said valve element and said piston, between said piston and said second urging means, and between said second urging means and said case.
12. The pressure regulating valve according to claim 1, utilized in high-pressure gas pressure regulation.
13. The pressure regulating valve according to claim 1, utilized in pressure regulation of fuel gas.
14. A fuel gas supply system comprising a fuel gas supply source and the pressure regulating valve according to claim 1.
15. The fuel gas supply system according to claim 14 comprising a fuel gas container or a fuel gas consuming member, which is connected to said secondary chamber of said pressure regulating valve.
16. The fuel gas supply system according to claim 14, wherein said fuel gas is hydrogen gas.