Vehicle Drivetrain Freewheel With Single-Ring Pawl Switching
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Solution Overview
Problem
Existing motor vehicle drive train freewheels require multiple actuators and sensors to separately lock and unlock rotational directions, making them costly and complex to produce.
Innovation Solution
A freewheel design with a rotating locking pawl carrier and pivotable locking pawls, utilizing a single switching ring and actuator to load locking pawls in opposite directions, allowing for cost-effective production with minimal sensors and actuators, enabling efficient coupling and decoupling of the shaft in both rotational directions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple actuators and sensors are used to separately lock and unlock rotational directions, then the locking and unlocking function is reliable, but the production cost and device complexity increase
Solution Approach 1:
The patent combines multiple locking pawls (first locking pawl and second locking pawl) onto a single rotating locking pawl carrier, which is actuated by a single actuator. The switching ring integrates the control function for both locking pawls, allowing one actuator to control multiple locking mechanisms. This merging approach reduces the number of actuators and sensors while maintaining reliable locking and unlocking functionality in both rotational directions.
Solution Approach 2:
The locking pawl carrier serves multiple functions: it carries both the first locking pawl and the second locking pawl, and its single rotational movement controls the engagement and disengagement of both pawls simultaneously. The switching ring also performs multiple functions by controlling the positioning of both locking pawls through its axial displacement. This multi-functionality reduces the overall number of components needed.
2Manufacturing precision
If multiple actuators and sensors are used to separately lock and unlock rotational directions, then the locking control is precise, but the manufacturing cost increases
Solution Approach 1:
By merging the control of both locking pawls into a single actuator-system, the patent reduces component count and assembly complexity, directly lowering manufacturing costs. The integrated switching ring and locking pawl carrier maintain precise control through mechanical design rather than multiple independent actuation systems.
Solution Approach 2:
The locking pawls are designed to engage and disengage automatically based on the rotational direction and the position of the switching ring. The system uses the rotational motion itself to control the locking mechanism, reducing the need for complex external actuation systems and sensors, thereby simplifying manufacturing.
3Ease of manufacture
If a single switching ring and actuator are used to control locking pawls, then the production cost is reduced, but the complexity of controlling multiple locking pawls increases
Solution Approach 1:
The switching ring is designed with asymmetric features including a first rod for controlling the first locking pawl and a second rod for controlling the second locking pawl. These rods are positioned and dimensioned differently to accommodate the specific control requirements of each locking pawl, allowing a single switching ring to manage multiple pawls with different control characteristics through its axial displacement.
Solution Approach 2:
The switching ring acts as an intermediary component that translates the single actuator's axial motion into differential control of multiple locking pawls. The first and second rods on the switching ring serve as intermediaries that distribute the control motion to the respective locking pawls, simplifying the overall control architecture while maintaining the ability to control multiple pawls.
4Productivity
If locking pawls are engaged asynchronously in different rotational directions, then the operational efficiency is improved, but the synchronization control becomes more complex
Solution Approach 1:
The locking pawls are designed to engage and disengage dynamically based on the rotational direction and the position of the switching ring. The system allows asynchronous engagement of the first and second locking pawls depending on the operational requirements, with the switching ring's axial position determining which pawl is active. This dynamic control enables efficient operation in both rotational directions without requiring complex synchronization mechanisms.
Data Source
AI summary
A freewheel for a motor vehicle drive train includes a locking pawl carrier which is rotatable with respect to a rotational axis, first and second locking pawls fastened pivotably in a locking pawl receptacle where the locking pawl receptacle is fixedly coupled to the locking pawl carrier. A shaft is rotatable about the rotational axis and has first and second coupling depressions in which the first and second locking pawls are respectively engageable. A switching ring is coupled fixedly to the locking pawl carrier so as to rotate with the locking pawl carrier and the switching ring is movable along the rotational axis by an actuator. A position of the switching ring is detectable by a sensor. A movement of the switching ring in one direction loads the first and second locking pawls in opposite pivoting directions and fixes a position of the first and second locking pawls.