초록 ▼

A two way closed-center solenoid valve provides effective areas upon the valve members which result in static pressure balancing of these members. Additional feedback areas are provided and exposed to fluid pressure which approximates a first time derivative of fluid pressure at an outlet port of th

A two way closed-center solenoid valve provides effective areas upon the valve members which result in static pressure balancing of these members. Additional feedback areas are provided and exposed to fluid pressure which approximates a first time derivative of fluid pressure at an outlet port of the solenoid valve. Accordingly, an input signal is opposed dynamically approximately as a first time derivative of fluid pressure delivered to the output port. The feedback areas are larger in effective area than the effective areas upon the valve members to provide a favorable margin of feedback forces over static and dynamic frictions.

대표청구항 ▼

Servo valve apparatus comprising: a housing defining an inlet port, an outlet port, a vent port, and a flow path communicating each port with the others; a pair of relatively movable valve members movably received by said housing, a first of said pair of valve members sealingly cooperating in a firs

Servo valve apparatus comprising: a housing defining an inlet port, an outlet port, a vent port, and a flow path communicating each port with the others; a pair of relatively movable valve members movably received by said housing, a first of said pair of valve members sealingly cooperating in a first position to close fluid communication between said inlet port and said outlet port while defining a respective first sealing area, said first valve member further sealingly and movably cooperating with said housing to close fluid communication between said inlet port and said vent port while defining a second sealing area substantially equal with said first sealing area, said first valve member in a respective second position opening fluid communication between said inlet port and said outlet port, said first valve member further defining a passage communicating said outlet port with said vent port; a second of said pair of valve members in a respective first position thereof sealingly cooperating with said first valve member to close said passage and fluid communication between said outlet port and said vent port while defining a third sealing area substantially equal to said first and said second sealing areas, said second valve member moving to a respective second position opening fluid communication between said outlet port and said vent port via said passage; input means for moving either selected one of said pair of valve members to said respective second position thereof; feedback means for urging said selected one of said pair of valve members from said second position toward the respective first position thereof substantially as a first time derivative of fluid pressure at said outlet port, said feedback means defining a pair of concentric oppositely disposed faces, a first of said pair of faces defining an area significantly exceeding said first, second, and third sealing areas individually and being disposed to urge said second valve member from its respective second position toward said first position thereof in response to fluid pressure thereon, the other of said pair of faces defining an area substantially equal to the area difference between said first face area and said first, second, and third sealing areas individually, said other face being disposed to exert a force tending to allow movement of said first valve member from its second position toward said first position thereof in response to fluid pressure thereon, and flow path means freely communicating fluid pressure from said outlet port to said other face and restrictively communicating to said first face fluid pressure from said outlet port according to a first time derivative thereof; said input means comprising a magnetic armature position and a spaced apart pair of electromagnetic stator means for moving said armature portion from a respective first centered position wherein said pair of valve members both occupy their respective first positions alternatively to respectively opposite second and third position wherein a selected one of said pair of valve members is moved to its respective second position; said feedback means including a stepped piston portion sealingly cooperating with said housing to define a pair of chambers and said pair of oppositely disposed faces respectively bounding individually a respective one of said pair of chambers; and said input means carrying said stepped piston portion intermediate of said armature portion and an end of said input means which operatively contacts one of said pair of valve members.