Automotive Motor Drive Clutch Decoupling via Reverse Rotation
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Solution Overview
Problem
Existing motor drive transmission control devices with clutches between electric drive motors and vehicle wheels face challenges in decoupling during two-wheel drive mode, leading to unnecessary energy waste and potential over-speed rotation due to locked clutch positions, especially when transitioning from four-wheel drive to two-wheel drive.
Innovation Solution
A motor drive transmission control device with a rotational direction estimating unit and a clutch release unit that allows the retainer to be released with a lower torque than required for wheel drive, ensuring the clutch can be decoupled even when locked, preventing reverse input from wheels and reducing energy waste by avoiding unnecessary electric drive motor operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the clutch is locked in the coupling position to protect the electric drive motor from reverse input, then the motor protection is improved, but the energy waste increases and over-speed rotation may occur when transitioning to two-wheel drive mode
Solution Approach 1:
The clutch mechanism transitions from a static locked state to a dynamic controllable state. The engagement elements can be actively disengaged by rotating the inner member in the reverse direction, allowing the clutch to switch between coupled and decoupled states based on operational requirements, thereby preventing energy waste while maintaining motor protection capability
Solution Approach 2:
The rotational direction of the inner member is changed to achieve clutch disengagement. By rotating the inner member in the reverse direction (opposite to the normal drive direction), the engagement elements are moved from the engaged position to a disengaged position, changing the clutch's coupling parameter from locked to unlocked state
2Power
If the engagement elements are locked within the engagement spaces to maintain clutch coupling, then the torque transmission is improved, but the decoupling reliability deteriorates when the retainer is released
Solution Approach 1:
Instead of using the normal rotational direction to disengage the clutch, the invention uses the reverse rotational direction of the inner member. This inverted approach allows the engagement elements to be actively pushed out of the engagement spaces by rotating the inner member backward, ensuring reliable decoupling even when the retainer is released
Solution Approach 2:
Before fully releasing the retainer, the inner member is first rotated in the reverse direction to pre-position the engagement elements in a state that facilitates easy disengagement. This preliminary action ensures that when the retainer is subsequently released, the engagement elements can be reliably disengaged without remaining locked in the engagement spaces
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 solution effectively decouples the clutch during two-wheel drive mode, preventing reverse input to the electric drive motor and reducing energy waste by ensuring the clutch is in a decoupling position, thus enhancing operational efficiency and preventing over-speed issues.
Implementation Method 1
a wedge shaped engagement space S is defined by each of cam face 6 between an outer member 1, which forms a rotatable member linked with the wheels, and an inner member 4, which forms a rotatable member linked with the electric drive motor
Data Source
AI summary
A clutch (60) of a type including engagement elements (9) interposed between rotatable members (4, 1) on motor and wheel sides, respectively is disposed between an electric drive motor (51) and wheels (56). This clutch (60) includes a retainer constraining mechanism (21) for selectively constraining and releasing a retainer (7) retaining the engagement elements (9) so that when the retainer (7) is constrained, rotation in any one of two directions opposite to each other can be transmitted. A rotational direction estimating unit (63) estimates the direction of rotation of the electric drive motor (51) immediately before the motor being halted during the halt of the automotive vehicle or immediately before the halt of the automotive vehicle. A clutch release unit (64) operates, when the automotive vehicle is to be started from a halted condition by means of a different drive system (41) under the two wheel drive mode, to cause the retainer constraining mechanism (21) to release the retainer (7) after the electric drive motor (51) has been driven in a direction reverse to that estimated by the rotational direction estimating unit (63), with a torque lower than that required to drive the wheels (56).