Two stage piston for faster clutch apply

摘要

A clutch assembly, including: a secondary piston assembly; a primary piston including a portion located radially outward of the secondary piston assembly; a first chamber at least partially formed by a first side of the primary piston; a second chamber at least partially formed by the secondary piston assembly and a second side of the primary piston; and a check valve connecting the first and second chambers. For a first force applied by fluid in the first chamber: the primary piston remains axially stationary; the fluid flows from the first chamber into the second chamber; and the secondary piston assembly displaces in a first axial direction to contact a clutch pack. For an increase of the first force to a second force: fluid flow between the first and second chambers is blocked by the check valve; and the primary piston and the secondary piston assembly displace in the first axial direction to close the clutch pack.

主权项

1. A clutch assembly, comprising:
a secondary piston assembly; a primary piston including a portion located radially outward of the secondary piston; a first chamber at least partially formed by a first side of the primary piston; a second chamber at least partially formed by the secondary piston assembly and a second side of the primary piston; and, a check valve connecting the first and second chambers, wherein:
for a first force applied by fluid in the first chamber:
the primary piston remains axially stationary;the fluid flows from the first chamber into the second chamber; and,the secondary piston assembly displaces in a first axial direction to contact a clutch pack; and,for an increase of the first force to a second force:
fluid flow between the first and second chambers is blocked by the check valve; and,the primary piston and the secondary piston assembly displace in the first axial direction to close the clutch pack.