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US 12,247,658 B2Granted
Electric park systems, transmissions incorporating the same, and methods for transmissions
AssigneeAllison Transmission, Inc.
InventorsJames Raszkowski, Isaac Mock
Life of this patent
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Abstract
Transmissions, park systems, and methods of operating transmissions are disclosed herein. A transmission includes 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 includes a park actuation assembly having a park gear in direct contact with the output shaft, an actuator to supply rotational power, and an actuation linkage coupled between the actuator and the park actuation assembly.
Claims20
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.
6 more elements
A park system to selectively brake an output shaft of a transmission, the park system comprising:
- a park actuation assembly having a park gear in direct contact with the output shaft,
- an electric actuator to supply rotational power, and
- an actuation linkage coupled between the electric actuator and the park actuation assembly,
- wherein in use of the park system, the electric 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,
- wherein the actuation linkage comprises a screw directly coupled to the electric actuator to receive rotational power therefrom and a nut threadably locked to the screw for translation along a first longitudinal axis in response to rotation of the screw, and
- wherein at least one hanger limits translation of the screw and the nut along the first longitudinal axis and includes an aperture through which the screw extends.
3 more elements
A park system to selectively brake an output shaft of a transmission, the park system comprising:
- a park actuation assembly having a park gear in direct contact with the output shaft,
- an electric actuator to supply rotational power, and
- an actuation linkage coupled between the electric actuator and the park actuation assembly including a screw directly coupled to the electric actuator to receive rotational power therefrom and a nut threadably locked to the screw for translation along a first longitudinal axis in response to rotation of the screw,
- wherein a pair of hangers limit translation of the screw and the nut along the first longitudinal axis and each include an aperture through which the screw extends.
1 more element
Dependencies are inferred from the claim text.