US 12,253,116 B1
Hydraulic piston design
Ionut Manta, Avon, IN (US); and Evan Meredith, Indianapolis, IN (US)
Assigned to Allison Transmission, Inc., Indianapolis, IN (US)
Filed by Allison Transmission, Inc., Indianapolis, IN (US)
Filed on Aug. 22, 2023, as Appl. No. 18/453,441.
Int. Cl. F16D 25/0638 (2006.01); F16D 48/02 (2006.01)
CPC F16D 25/0638 (2013.01) [F16D 25/14 (2013.01)] 14 Claims
OG exemplary drawing
 
1. A system, comprising:
a clutch assembly including
a clutch pack,
a housing defining a bore,
a piston being slidably disposed in the bore,
wherein the piston is configured to actuate the clutch pack,
wherein the piston has a head,
wherein the head has one or more pads extending from the head,
wherein the housing defines a flow passage into the bore,
wherein the flow passage is configured to both supply hydraulic fluid to the bore and exhaust the hydraulic fluid from the bore,
wherein the head includes an inner head and an outer head,
wherein the head defines a channel,
wherein the channel is defined between the inner head and the outer head,
wherein the inner head is disposed radially inwards relative to the outer head,
wherein the piston has an engaged position where the piston engages the clutch pack,
wherein the piston has a disengaged position where the piston is disengaged from the clutch pack,
wherein the bore has a bore head wall,
wherein the bore head wall faces the head of the piston,
wherein the one or more pads extend from the inner head to form a standoff,
wherein the one or more pads are absent from the outer head,
wherein the one or more pads define one or more gaps where the hydraulic fluid flows,
wherein the one or more pads are configured to contact the bore head wall when in the disengaged position,
wherein the inner head and the outer head each have a surface facing the bore head wall that are planar with one another,
wherein the one or more pads extend from the surface of the inner head farther than the surface of the outer head towards the bore head wall,
wherein the inner head defines an inner groove,
an inner gasket received in the inner groove,
wherein the inner gasket is configured to seal against the bore,
wherein the outer head defines an outer groove,
an outer gasket received in the outer groove,
wherein the outer gasket is configured to seal against the bore, and
wherein the inner gasket and the outer gasket axially overlap in a direction that is orthogonal to a rotational axis of the clutch assembly.