Selectable Dual-Direction One-Way Clutch With Low-Loss Locking
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Solution Overview
Problem
Conventional one-way clutches in automatic transmissions and battery electric vehicle axles face challenges in providing a cost-effective solution that allows for fully free rotation, full locking in both directions, and one-way clutch functionality in either direction, while minimizing parasitic losses and package size.
Innovation Solution
A dual direction, selectable one-way clutch with electromechanical actuation that includes concentric shafts, gear plates, pawl plates, and actuator rings, allowing for fully locked, one-way, and free rotational states, with power required only for state changes, utilizing a combination of drive and cam profiles and springs for engagement and disengagement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a conventional selectable one-way clutch is used, then it can provide one-way clutch functionality, but it requires a hydraulic pump, passages, controls, piston, and wet clutch pack resulting in large package size and parasitic losses
Solution Approach 1:
The patent replaces the hydraulic system (pump, passages, piston) with a purely mechanical actuation system using a solenoid that directly moves the actuator ring through magnetic field conversion to mechanical motion. This eliminates parasitic hydraulic losses while maintaining the selectable one-way clutch functionality.
Solution Approach 2:
The patent extracts and removes the unnecessary hydraulic components (pump, passages, controls, piston, wet clutch pack) from the system, retaining only the essential mechanical elements (solenoid, actuator ring, pawls, gear plates) needed to achieve the same functional outcome with reduced complexity and energy loss.
2Force
If a roller one-way clutch is used, then it provides good function, but the torque capability relies on friction requiring larger contact surfaces
Solution Approach 1:
The patent segments the torque transmission function into multiple discrete pawls that engage with gear teeth, distributing the torque load across several point contacts rather than relying on a single large friction surface. This allows high torque capability in a compact package.
Solution Approach 2:
Instead of using friction-based roller contact to transmit torque, the patent inverts the approach by using positive mechanical engagement through pawls that lock onto gear teeth, converting the torque transmission mechanism from friction-dependent to geometry-dependent for more efficient force transfer.
3Adaptability or versatility
If a ratcheting pawl one-way clutch is used, then it can carry substantial torque in a small package, but it is typically passive and cannot be selectively controlled
Solution Approach 1:
The patent transforms the passive ratcheting pawl mechanism into a dynamic, controllable system by introducing an actuator ring that can actively engage or disengage the pawls from the gear teeth. This allows the clutch to switch between locked, free-wheeling, and one-way states on demand, providing adaptability while maintaining compact dimensions.
4Reliability
If a clutch system provides full locking in both directions, then it ensures secure connection, but it requires additional actuation mechanisms compared to conventional one-way clutches
Solution Approach 1:
The patent merges the functions of multiple clutch states (one-way locking, two-way locking, and free-wheeling) into a single integrated mechanism using two gear plates with opposite-handed teeth and a common actuator ring. This unified design achieves reliable full locking in both directions without requiring separate actuation systems for each locking mode.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables efficient power transmission in either direction with low friction and fast state changes, scalable for various torque requirements, and reduces energy losses by only requiring power for active switching of the clutch states.
Implementation Method 1
A first spring is associated with each of the first pawls that biases the first ends of the first pawls into the engaged positions. A second spring is associated with each of the second pawls that biases the first ends of the second pawls into the engaged positions.
Implementation Method 2
A first actuator ring is provided that is axially movable between an actuated position, in which the second ends of the first pawls are in the activated position, and a disengaged position, in which the first actuator ring presses the second ends of the first pawls radially inwardly to the deactivated position
Data Source
AI summary
A dual direction, selectable one-way clutch is provided that can be set to be fully free to rotate in both directions, can be fully locked in both directions, and can provide a one-way clutch option in both directions. The actuator to change the clutch state is an electromechanical and only requires power to change a coupling state of the clutch. The clutch is formed by two sets of gear plates and corresponding engagement pawls that are engageable/disengageable in order to provide for the different locked and one-way clutch states. One or more actuator rings are provided to activate or disengage the pawls.