1. A load sense valve assembly, comprising:
a first valve in flow communication with a pump discharge line, the first valve comprising a solenoid actuated directional control valve;
a second valve in flow communication with the first valve, the second valve comprising a hydraulic pilot actuated directional control valve; and
a third valve in flow communication with the first valve, the third valve comprising a hydraulic pilot actuated directional control valve.
2. The valve assembly of claim 1, wherein the first valve is an electric solenoid actuated three-waytwo-position hydraulic directional control valve.
3. The valve assembly of claim 1, wherein the second valve is a hydraulic pilot actuated two-waytwo-position hydraulic directional control valve.
4. The valve assembly of claim 1, wherein the third valve is a hydraulic pilot actuated three-waytwo-position hydraulic directional control valve.
5. The valve assembly of claim 1, including a first hydraulic flow limiting valve in the flow path between the discharge line and the first valve.
6. The valve assembly of claim 1, including a second hydraulic flow limiting valve in the flow path between the first valve and the second valve.
7. The valve assembly of claim 1, including a third hydraulic flow limiting valve in the flow path between the first valve and the third valve.
8. The valve assembly of claim 1, wherein the second valve is connected to a valve outlet port to direct fluid flow to downstream system components.
9. The valve assembly of claim 1, wherein the third valve is connected to a load sense flow and pressure signal line from downstream operational components and is also connected to an outlet load sense flow and pressure signal line in flow communication with a control valve assembly of a pump.
10. The valve assembly as claimed in claim 1, connected to a pump assembly, the pump assembly comprising a variable displacement pump and a control valve.
11. A hydraulic system, comprising:
a pump;
a control valve in flow communication with the pump; and
a load sense valve assembly in flow communication with the pump and the control valve, the load sense valve assembly comprising:
a first valve comprising a solenoid activated directional control valve;
a second valve connected to the first valve, the second valve comprising a hydraulic pilot actuated directional control valve; and
a third valve connected to the first valve, the third valve comprising a hydraulic pilot actuated directional control valve.
12. The hydraulic system as claimed in claim 11, wherein the valve assembly has a first configuration in which hydraulic fluid supplied to the first valve is directed to a pilot chamber of the second valve and a pilot chamber of the third valve, such that fluid flow to downstream operators is blocked and the pump increases displacement to maintain a pre-set load sense differential standby pressure at an input port of the valve assembly.
13. The hydraulic system as claimed in claim 11, wherein the valve assembly has a second configuration in which hydraulic fluid supplied to the first valve is directed to the second valve and to downstream operators, and wherein the pump is controlled to maintain a pressure at an input port of the valve assembly equal to a pre-set load sense differential pressure plus a system demand operating pressure.
14. The hydraulic system as claimed in claim 11, wherein both the second valve and the third valve are connected to an output of the first valve such that a flow path state of the first valve simultaneously affects a flow path state of the second valve and third valve.
15. The hydraulic system as claimed in claim 11, wherein the first valve is a solenoid actuated three-waytwo-position hydraulic directional control valve.
16. The hydraulic system as claimed in claim 11, wherein the second valve is a hydraulic pilot actuated two-waytwo-position hydraulic directional control valve.
17. The hydraulic system as claimed in claim 11, wherein the third valve is a hydraulic pilot actuated three-waytwo-position hydraulic directional control valve.
18. A load sense valve assembly for a hydraulic system, the load sense valve assembly comprising:
a first valve connected to a variable displacement hydraulic pump and a hydraulic system control valve, the first valve comprising a solenoid actuated three-waytwo-position hydraulic directional control valve;
a second valve connected to the first valve and to a valve outlet port to selectively direct fluid to downstream system components, the second valve comprising a pilot actuated two-waytwo-position directional control valve; and
a third valve connected to the first valve, to a load sense flow and pressure signal line from the downstream system components, and to an outlet load sense flow and pressure signal line connected to the system control valve, wherein the second and third valves are connected to an output of the first valve such that a flow path state of the first valve simultaneously affects a flow path state of the second and third valves,
wherein the valve assembly has a first configuration in which hydraulic fluid supplied to the first valve is directed to a pilot chamber of the second valve and a pilot chamber of the third valve such that fluid flow to the downstream components is blocked and the pump increases displacement to maintain a pre-set load sense differential standby pressure at an input port of the valve assembly, and
wherein the valve assembly has a second configuration in which hydraulic fluid supplied to the first valve is directed to the second valve and to the downstream components, and wherein the pump is controlled to maintain a pressure at an input port of the valve assembly equal to a pre-set load sense differential pressure plus a system demand operating pressure.
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 temperature controlled crystal oscillator provided with a circuit substrate having a crystal resonator, an oscillating circuit, and a temperature control circuit, arranged on one or both principal surfaces, and a container main body that accommodates said circuit substrate and has mount terminals on an outer bottom surface thereof, wherein said temperature control circuit includes at least a first temperature sensor that detects an operating temperature of said crystal resonator, a second temperature sensor that detects a surrounding temperature of said container main body, wherein a metal film surrounds a periphery of said second temperature sensor, and a heating resistor that applies heat to said crystal resonator according to a temperatures detected by said first temperature sensor and said second temperature sensor, and lead wires extend from said circuit substrate and are connected electrically to said mount terminals,
wherein an insulation groove that passes through said circuit substrate in a thickness direction is formed between: a first lead wire closest to said second temperature sensor, wherein said first lead wire is electrically connected to said metal film, and said second temperature sensor; and said heating resistor.
2. A temperature controlled crystal oscillator according to claim 1, wherein said first lead wire that extends from said circuit substrate having said second temperature sensor arranged thereon and said insulation groove, functions as a ground.
3. A temperature controlled crystal oscillator according to claim 2, wherein one principal surface of said circuit substrate includes said insulation groove, and on which said second temperature sensor is arranged.
4. A temperature controlled crystal oscillator according to claim 1, wherein said second temperature sensor arranged on said circuit substrate having said insulation groove, is electrically connected to said first lead wire.
5. A temperature controlled crystal oscillator according to claim 1, wherein said second temperature sensor is arranged on one principal surface of said circuit substrate having said insulation groove, and said heating resistor is arranged on another principal surface of said circuit substrate.
6. A temperature controlled crystal oscillator according to claim 1, wherein said circuit substrate is of a planarly rectangular shape; said first lead wire and second to fourth lead wires extend from four corner sections of said circuit substrate; and between said heating resistor and at least one of said second to fourth lead wires, there is formed an insulation groove that passes through said circuit substrate in a thickness direction and corresponds to said second to fourth lead wires.
7. A temperature controlled crystal oscillator according to claim 1, wherein said insulation groove is of a narrow groove shape, and one end thereof is formed so as to open to an outer periphery of said circuit substrate.
8. A temperature controlled crystal oscillator according to claim 1, wherein said first temperature sensor is a thermistor, and said second temperature sensor is a linear resistor.
9. A temperature controlled crystal oscillator comprising:
a circuit substrate having a crystal resonator;
an oscillating circuit;
a container main body that accommodates said circuit substrate and has mount terminals on an outer bottom surface thereof;
a temperature control circuit, arranged on one or both principal surfaces of said circuit substrate, said temperature control circuit comprises:
at least a first temperature sensor that detects an operating temperature of said crystal resonator;
a second temperature sensor that detects a surrounding temperature of said container main body;
a metal film that surrounds a periphery of said second temperature sensor; and
a heating resistor that applies heat to said crystal resonator according to a temperatures detected by said first temperature sensor and said second temperature sensor;
lead wires extend from said circuit substrate and are electrically connected to said mount terminals; and
an insulation groove formed on at least one principal surface of said circuit substrate, on which said second temperature sensor is arranged, said insulation groove passes through said circuit substrate in a thickness direction formed between a first lead wire closest to said second temperature sensor and said second temperature sensor, and said heating resistor, and wherein said first lead wire is electrically connected to said metal film and functions as a ground.
10. A temperature controlled crystal oscillator provided with a circuit substrate having a crystal resonator, an oscillating circuit, and a temperature control circuit, arranged on one or both principal surfaces, and a container main body that accommodates said circuit substrate and has mount terminals on an outer bottom surface thereof, wherein said temperature control circuit includes at least a first temperature sensor that detects an operating temperature of said crystal resonator, a second temperature sensor that detects a surrounding temperature of said container main body, and a heating resistor that applies heat to said crystal resonator according to a temperatures detected by said first temperature sensor and said second temperature sensor, and lead wires extend from said circuit substrate and are connected electrically to said mount terminals,
wherein an insulation groove that passes through said circuit substrate in a thickness direction is formed between: a first lead wire closest to said second temperature sensor, and said second temperature sensor; and said heating resistor, and wherein said insulation groove is of a narrow groove shape, and one end thereof is formed so as to open to an outer periphery of said circuit substrate.