US 12,247,658 B2
Electric park systems, transmissions incorporating the same, and methods for transmissions
James Raszkowski, Indianapolis, IN (US); and Isaac Mock, Martinsville, IN (US)
Assigned to ALLISON TRANSMISSION, INC., Indianapolis, IN (US)
Filed by ALLISON TRANSMISSION, INC., Indianapolis, IN (US)
Filed on Sep. 28, 2022, as Appl. No. 17/954,942.
Prior Publication US 2024/0102555 A1, Mar. 28, 2024
Int. Cl. F16H 63/34 (2006.01)
CPC F16H 63/3466 (2013.01) [F16H 63/3425 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A transmission comprising:
an input shaft to receive torque from a drive unit;
an output shaft to transmit torque to a load; and
a park system to selectively brake the output shaft, the park system including
a park actuation assembly having a park gear in direct contact with the output shaft,
an actuator, and
an actuation linkage coupled between the actuator and the park actuation assembly to be moved by the actuator,
wherein in use of the transmission, the actuator drives operation of the park actuation assembly through the actuation linkage such that the park system is operable in (i) an engaged state, in which rotation of the park gear is constrained to resist rotation of the output shaft, (ii) a disengaged state, in which rotation of the park gear is permitted to allow rotation of the output shaft, and (iii) a staged state distinct from the engaged state and the disengaged state which facilitates a transition to the engaged state in an event of an electrical failure or when park is selected by an operator, and
wherein the actuation linkage comprises a screw directly coupled to the actuator to be driven by the actuator, a nut or axial cam coupled to the screw for translation along a first longitudinal axis in response to movement of the screw, a lever directly coupled to the nut at one end of the lever, a sleeve directly coupled to the lever at another end of the lever arranged opposite the one end, and a rod supporting the sleeve and adapted for translation along a second longitudinal axis arranged parallel to the first longitudinal axis.