Hydraulic control apparatus with an adjustable throttle
First Claim
1. A hydraulic control steering apparatus, comprising, a throttle valve unit having fixed and moveable valve elements forming an adjustable throttle relative to a sealing face on said element, said fixed element having a slot shaped orifice with edges in said sealing face, said moveable element having bounding throttle surfaces with trailing edges engageable with said sealing face and leading edges spaced a distance t from said sealing face, said moveable element having a slot shaped orifice with transversely extending edges thereof defined by said leading edges of said bounding surfaces, said bounding surfaces being respectively cooperable with said edges of said fixed element orifice and forming a variable length throttle passage with said sealing face, said throttle passage being relatively flat by reason of said bounding surface having a large breath relative to said t, and at least one of said bounding surfaces having an exponential function section relative to said sealing surface.
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Accused Products
Abstract
The invention relates to a hydrostatic steering control unit of the type having valving for an open center neutral position which bypasses pressurized fluid from the pump to the tank when in neutral. During a turning operation with a steering wheel the open center valving is caused to close and the pressurized fluid is directed to one side or the other of a servomotor which is connected to wheels to be steered. The open center valving includes orifices in relatively rotatable elements which are aligned in the neutral position and closed to effect the turning operation. Open center valving can be the cause of noise and cavitation and such valving herein is provided with slot shaped orifices and flat generally wedge shaped throttle passages to minimize the noise and cavitation problems. The throttle passages are defined by curved bounding surfaces having rectangularly shaped outlines. A characteristic of the curved surfaces is that they are formed with exponentially shaped sections.
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Citations
9 Claims
- 1. A hydraulic control steering apparatus, comprising, a throttle valve unit having fixed and moveable valve elements forming an adjustable throttle relative to a sealing face on said element, said fixed element having a slot shaped orifice with edges in said sealing face, said moveable element having bounding throttle surfaces with trailing edges engageable with said sealing face and leading edges spaced a distance t from said sealing face, said moveable element having a slot shaped orifice with transversely extending edges thereof defined by said leading edges of said bounding surfaces, said bounding surfaces being respectively cooperable with said edges of said fixed element orifice and forming a variable length throttle passage with said sealing face, said throttle passage being relatively flat by reason of said bounding surface having a large breath relative to said t, and at least one of said bounding surfaces having an exponential function section relative to said sealing surface.
Specification