CONTROLLER FOR FLUID OPERATED DEVICE

• US 3,801,239 A
• Filed: 04/03/1972
• Issued: 04/02/1974
• Est. Priority Date: 04/03/1972
• Status: Expired due to Term

• Current Assignee: Bernard J. Larson
• Original Assignee: Bernard J. Larson
• Inventors: Larson, Bernard J.
• Primary Examiner(s): Croyle, Carlton R.
• Assistant Examiner(s): Koczo, Jr., Michael
• Application Number:
  US05/240,418
• Time in Patent Office: 729 Days
• Field of Search: 418/130,131,133,61 180/79.2R 91/467,375,388 60/384
• US Class Current: 418/61.3
• CPC Class Codes: B62D 5/097 gerotor type

Abstract

A controller for a fluid pressure operated device has a section for metering control fluid through the controller to the pressure operated device. The meter section of the controller is enclosed in a pressurizable housing. A static pressure head equal to the control fluid pressure within the meter is applied to the casing and acts on the external surfaces of the meter to eliminate leakage out of metering elements during operation of the controller and to thereby reduce or eliminate '"'"''"'"''"'"''"'"'slip'"'"''"'"''"'"''"'"' between an input member of the controller and the fluid pressure operated device. Additionally, this pressure head is used to create a frictional braking force resisting movement of the movable element of the meter.

Claims

1. A controller for a fluid pressure operated device, said controller comprising a housing having an inlet port, and a control fluid outlet port, a member disposed in said housing and movable under the influence of fluid pressure to meter the volume of fluid which passes out of said control port during operation of said controller, and means for applying a braking force to said movable member which is proportional to the outlet pressure at said control port, said movable member comprising an externally toothed member having parallel end surfaces, said housing including an internally toothed member, and parallel end walls, said externally toothed member being disposed between said end walls with its opposite end surfaces adjacent thereto, the teeth of said members intermeshing to form expanding and contracting fluid chambers for metering control fluid during operation of said controller, said means for applying a braking force to said movable member comprising means for pressure biasing one of the ends of said externally toothed member into frictional engagement with one of said end walls including said movable member having a bore extending axially therethrough, said bore normally being exposed to a pressure which is substantially below the pressure in said fluid chambers, means for sealing said bore to prevent flow therethrough, and a leakage clearance between one of said end surfaces and the adjacent end wall whereby one of said end surfaces may be exposed to pressure in said fluid chambers.

2. The invention of claim 1 including a pressurizable casing surrounding and enclosing said internally and externally toothed members, and means for pressurizing said casing to the pressure in said fluid chambers to thereby control distortion of said members due to fluid pressure in said chambers during operation of said controller.

3. The invention of claim 2 wherein said means for pressurizing said casing includes passage means extending from said leakage clearance through one of said end walls to the interior of said casing.

4. A controller for a fluid operated device, said controller comprising a housing, a first portion of said housing having an internally toothed member and a pair of axially spaced fixed end walls defining a chamber, an externally toothed member disposed for orbital and rotational movement about an axis in the chamber, the teeth of said internally and externally toothed members forming expanding and contracting volume chambers during relative movement therebetween to measure the volume of fluid which passes through said chamber, said externally toothed member having parallel end surfaces and a splined bore extending axially therethrough, a second portion of said housing defining an inlet port, a return port, a control port, and a valve chamber, valve means disposed in the valve chamber and operable to feed an exhaust pressurized fluid through said expanding and contracting volume chambers upon movement thereof, and drive means connecting said valve means for follow up movement in synchronism with one of the movements of said externally toothed member, said drive means including a shaft having a splined end received in and drivingly engaging the splined bore of said externally toothed member, the improvement which comprises said externally toothed member having a counterbored recess in one end surface thereof surrounding said splined bore, a plate member disposed in said recess and sealing said splined bore to prevent fluid leakage therethrough and to provide a continuous end surface extending across one end of said externally toothed member, the distance between said fixed end walls of said housing being slightly greater than the width of said externally toothed member to enable one of the end surfaces of said externally toothed member to be entirely exposed to fluid pressure in the expanding and contracting volume chambers, and means in said housing for directly exposing at least a portion of the other end surface of said externally toothed member to a relatively lower fluid pressure to provide a resultant axial force acting on said externally toothed member and urging said externally toothed member into sealing engagement with one of said end walls.

5. The invention of claim 4 including a pressurizable casing surrounding and enclosing said internally and externally toothed members, and means for pressurizing said casing to the pressure in said fluid chambers during operation of said controller to thereby control distortion of said members due to fluid pressure in said chambers.

6. A controller for a fluid pressure operated device, said controller comprising a housing, a first portion of said housing having an internally toothed member and a pair of axially spaced end walls defining a pressurizable metering chamber, an externally toothed member disposed in said chamber for rotational and orbital movement about an axis thereof, the teeth of said members interengaging to form expanding and contracting volume chambers during relative movement therebetween, said externally toothed member having an end surface disposed parallel to and in confronting relationship with each of said end walls, means for exposing one of the end surfaces of said externally toothed member directly to the fluid pressure in said expanding and contracting volume chambers, and means for exposing at least a portion of the opposite end surface of said externally toothed member directly to a lower fluid pressure to provide a resultant axial force acting directly on said one end surface of said externally toothed member urging said externally toothed member into sealing engagement with the opposite end wall of said metering chamber during operation of said controller.