Bi-directional Clutch Assembly with Selectable One-Way Clutches

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Solution Overview

Problem

Conventional dog-type disconnect clutches in hybrid/electric vehicles have high backlash angles, require high release forces to disengage, and do not allow ratcheting behavior, limiting their functionality in providing a disconnect feature in electric drive modes.

Innovation Solution

A bi-directional clutch assembly with a pair of selectable one-way clutches (SOWC) that provides four distinct operating modes: LOCK-LOCK, FREEWHEEL, LOCK-RATCHET, and RATCHET-LOCK, allowing for selective connection and disconnection of input and output shafts, and enabling a rotary disconnect feature between rotary components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If conventional dog-type disconnect clutches are used, then the disconnect feature is provided, but high backlash angles and high release forces are incurred

Engineering Contradiction:

Improverelease forceVSAvoidbacklash angle

Core Design Contradiction:

Ease of operationVSObject-generated harmful factors

Solution Approach 1:

The clutch assembly is segmented into multiple independent SOWC units (first and second SOWC) that can operate independently. Each SOWC has its own active struts and coil units, allowing selective engagement/disengagement to achieve different operating modes (LOCK-LOCK, FREEWHEEL, LOCK-RATCHET, RATCHET-LOCK), thereby reducing overall backlash and release forces compared to a single dog-type clutch

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent replaces the conventional mechanical dog-type clutch engagement mechanism with an electromagnetic actuation system. Coil units generate magnetic fields to move armatures, which in turn control the deployment of active struts. This electromagnetic-mechanical hybrid system eliminates the high release forces and backlash associated with pure mechanical engagement

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Adaptability or versatility

If conventional dog-type disconnect clutches are used, then the disconnect feature is provided, but ratcheting behavior is not allowed

Engineering Contradiction:

Improveoperating modesVSAvoidfunctional flexibility

Core Design Contradiction:

Adaptability or versatilityVSEase of operation

Solution Approach 1:

The clutch assembly is designed as a multi-functional device that can operate in four distinct modes: LOCK-LOCK (both SOWC engaged), FREEWHEEL (both SOWC disengaged), LOCK-RATCHET (first SOWC engaged, second disengaged), and RATCHET-LOCK (first SOWC disengaged, second engaged). This universal design allows the same assembly to handle various operational requirements including unidirectional overrun conditions, bidirectional torque transmission, and complete disconnection

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The clutch system employs dynamic control through independent actuation of the first and second coil units. The system can transition between different operating modes by selectively energizing or de-energizing the coil units, allowing the active struts to dynamically deploy or retract based on real-time operational requirements, thereby enabling ratcheting behavior and improved adaptability

Inventive Principle:

Principle #15Dynamics

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

The bi-directional clutch assembly enhances the functionality of overrunning coupling devices by providing a disconnect feature in hybrid/electric axles and transaxles, reducing backlash and release forces, and accommodating unidirectional overrun conditions, thus improving the efficiency of electric drive modes.

Implementation Method 1

a first armature fixed for rotation with the outer race and being axially moveable between a non-actuated position and an actuated position in response to energization of the first coil unit

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentUS11519468B2Rotating e-clutch assembly providing four operating modes

Publication Date: 2022.12.06 MAGNA POWERTRAIN INC(CA)

AI summary

A bi-directional clutch assembly equipped with a pair of laterally-spaced, selectable one-way clutches configured in a compact arrangement. The bi-directional clutch assembly establishes a LOCK-LOCK mode when both SOWC's are non-actuated, establishes a FREEWHEEL mode when both SOWC's are actuated, and establishes a pair of LOCK-RATCHET mode when one SOWC is actuated and the other is not actuated. Coils units of the SOWC's are energized to shift an actuator toward active struts of an outer race. The actuator is rotationally fixed to the outer race. The active struts are biased toward the deployed position, and the actuator is biased toward the non-actuated position. The actuator includes a strut engagement feature that contacts the active struts and causes pivotal movement of the active struts to the non-deployed position.