Selectable detent assembly with neutral protection
View Patent ↗A selectable detent assembly that has a housing with a plurality of passageways. Within the housing is a selector spool that is disposed within a selector passageway and is rotatable to provide a plurality of rotational positions including a no detent position, a kick down position, and a continuous detent position. A pilot check valve is disposed within the housing and provides a fluid flow path from a pilot passageway to the selector passageway and a detent passageway. A detent arming piston is disposed within the detent passageway and is connected to a directional control valve spool. Thus, depending on the rotational position of the selector spool, the selector spool can either provide a continuous flow path through the selector passageway to a tank, a flow path that is controlled by the axial position of the selector spool or prevent flow to the tank in order to operate the detent arming piston.
1. A selectable detent assembly comprising:
a housing having a selector passageway, a pilot passageway and a detent passageway disposed therein;
a selector spool disposed within the selector passageway and rotatable to provide a plurality of rotational positions;
a pilot check valve disposed within the housing and providing a fluid flow path from the pilot passageway to the selector passageway and the detent passageway;
a detent arming piston disposed within the detent passageway, operatively connected to a directional control valve spool and in fluid communication with the selector passageway; and
wherein in a plurality of rotational positions of the selector spool provide a plurality of fluid flow paths through the selectable detent assembly.
2. The selectable detent assembly of claim 1 wherein in a first rotation position the selector spool provides a continuous fluid flow path through the selector passageway to a tank.
3. The selectable detent assembly of claim 2 wherein in a second rotational position the selector spool is axially movable from a first axial position that provides a fluid flow path through the selector passageway to the tank and a second axial position that prevents fluid flow through the detent passageway to the tank.
4. The selectable detent assembly of claim 3 wherein in a third rotational position the selector spool prevents fluid flow through the detent passageway to the tank.
5. The selectable detent assembly of claim 1 further comprising a pilot relief valve disposed within the housing and providing a second fluid flow path from the pilot passageway to the selector passageway.
6. The selectable detent assembly of claim 1 further comprising a selector spool bias spring engaging a selector shaft to bias the selector spool axially.
7. The selectable detent assembly of claim 1 wherein the operative connection between the detent arming piston and the directional control valve spool comprises a detent biasing spring engaging the detent arming piston at a first end and a detent center ball at a second end and wherein the detent center ball engages detent satellite balls that engage the directional control spool valve.
8. The selectable detent assembly of claim 1 wherein an orifice is disposed in an auxiliary passageway disposed between the pilot passageway and a tank to regulate the flow of fluid from the pilot passageway to the tank.