초록 ▼

Disclosed is an improved hydraulic control comprising a fail-to-neutral module. As is conventional, the hydraulic control comprises a main spool and a fluid flow path comprising a bridge circuit including a driver stage. The fail-to-neutral module comprises means defining a fail-to-neutral orifice w

Disclosed is an improved hydraulic control comprising a fail-to-neutral module. As is conventional, the hydraulic control comprises a main spool and a fluid flow path comprising a bridge circuit including a driver stage. The fail-to-neutral module comprises means defining a fail-to-neutral orifice which (a) is located in the fluid flow path upstream of the bridge circuit and (b) has a relatively large flow area but a maximum dimension smaller than the smallest orifice in the pilot stage. Preferably the means comprise a pin positioned through a hole, the pin and the hole both being circular in cross-section and coaxial, and the fail-to-neutral orifice is the clearance between the pin and the boundary of the hole.

대표청구항 ▼

A hydraulic control comprising: (a) a main spool; (b) a fluid flow path operatively connected to said main spool and comprising a bridge circuit containing a plurality of orifices at least one of which is a variable orifice; and (c) means defining a fail-to-neutral orifice which (i) has a flow area

A hydraulic control comprising: (a) a main spool; (b) a fluid flow path operatively connected to said main spool and comprising a bridge circuit containing a plurality of orifices at least one of which is a variable orifice; and (c) means defining a fail-to-neutral orifice which (i) has a flow area large enough so that it does not cause an appreciable pressure drop but a maximum dimension smaller than the smallest orifices in the bridge circuit, said maximum dimension being small enough so that the fail-to-neutral orifice serves as a filter for contaminants in fluid passing through said fluid flow path, and (ii) is located in said fluid flow path upstream of the bridge circuit, said means comprising a pin positioned through a hole, the fail-to-neutral orifice being the clearance between the pin and the boundary of the hole.