Patent Number: 6,170,381

Title: Control valve seal

Abstract: A fluid power apparatus having a housing with a bore therein which is divided by a power piston into an inlet chamber and an outlet chamber. The power piston has a passageway for connecting the inlet chamber with an outlet chamber. A valve arrangement controls the flow of a fluid under pressure from a source through the passageway. The valve arrangement including a valve seal, a valve spring and an input rod. The valve spring urges the valve seal into engagement with the input rod to define a working chamber within said passageway. The fluid under pressure flows from the inlet chamber to the outlet chamber by passing between the valve seal and a valve seat located in the working chamber. The flowing of fluid past the valve seat in a rest mode of operation develops a turbulence which creates a broad band non-resonance sound having an acceptable audible level of approximately 30 dB. The input rod responds to an actuation force from an operator by moving the valve seal toward the valve seat to restrict the flow of fluid from the working chamber. The restriction in the flow of fluid causes a corresponding fluid pressure change of the fluid in the inlet chamber. This corresponding fluid pressure change acts on the power piston to create an output force. The restriction in the flow of fluid from the working chamber creates a turbulence which produces an undesirable resonance noise. The valve seal is characterized by a labyrinth ring located on a face which modifies the level of turbulence and shifts the frequency of the fluid flowing past the valve seat such that the resonance noise of the fluid is below an acceptable audible range of 65 dB.

Inventors: Cramer; Kim David (New Troy, MI), Malosh; James Boyd (Baroda, MI)

Assignee: Robert Bosch Corporation

International Classification: B60T 13/10 (20060101); B60T 13/16 (20060101); B60T 17/00 (20060101); F15B 009/10 ()

Expiration Date: 01/09/2018