Friction-Induced Overrunning Clutch Actuation
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Solution Overview
Problem
Existing overrunning clutches in motor vehicle drivetrains face issues with noise generation, torque transmission efficiency, complexity, and compactness, particularly in applications requiring high torque and silent operation.
Innovation Solution
A self-switching overrunning clutch design featuring a torque-introducing and torque-receiving clutch member with a switching member that utilizes a friction-force-induced actuating force, mediated by an actuator in frictional contact, to transition between engagement and overrun positions, eliminating the need for pivot axle mountings and allowing for compact and silent operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If spring-loaded ratchets are used to control switching member positions, then the clutch can transmit torque in the load direction, but noise is generated due to the sweeping action of latches across detents
Solution Approach 1:
The patent replaces the traditional mechanical spring-loaded ratchet system with a friction-based actuating mechanism. The actuator uses friction forces generated by differential rotation between the torque-introducing clutch member and the actuator itself to switch the switching member between engagement and overrun positions, eliminating the need for spring-loaded latches that sweep across detents and generate noise.
Solution Approach 2:
The patent introduces an intermediate actuator mechanism that mediates between the torque-introducing clutch member and the switching member. This actuator uses friction pairing with the torque-introducing clutch member to generate actuating forces, which are then transmitted through actuation detents to control the switching member, thereby avoiding direct mechanical interaction between latches and detents.
2Reliability
If pivot axle mountings are used for switching members, then the clutch can achieve reliable engagement, but the construction becomes complex and manufacturing becomes difficult
Solution Approach 1:
The patent extracts and eliminates the pivot axle mounting mechanism from the clutch design. The switching member is controlled through friction-based actuation forces applied to its bearing surface, removing the need for pivot axles and their associated complex mounting structures, thereby simplifying both construction and manufacturing.
Solution Approach 2:
The switching member utilizes its own bearing surface against the actuator as a self-contained mechanism for receiving actuating forces. This eliminates the need for external pivot axle mountings, as the bearing surface itself serves as the interface for force transmission, simplifying the overall construction.
3Volume of moving object
If a compact design is implemented for motor vehicle applications, then space is saved, but torque transmission capability is limited
Solution Approach 1:
The patent changes the fundamental parameter of force generation from spring-loaded mechanical advantage to friction-based force generation. The friction pairing between the actuator and torque-introducing clutch member allows for high actuating forces in a compact configuration, enabling adequate torque transmission capability within a reduced volume suitable for motor vehicle applications.
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 design achieves high torque transmission with reduced noise and complexity, ensuring reliable and compact integration in motor vehicle drivetrains while maintaining silent operation in the overrun rotation direction.
Implementation Method 1
the actuating force is a friction-force-induced actuating force which is induced by a friction-force pairing between the actuator and a component of the overrunning clutch that is in frictional contact with said actuator
Data Source
AI summary
The disclosure relates to an overrunning clutch, comprising a torque-introducing clutch element, a torque-receiving clutch element and switching element, which is forced from an engagement position into a freewheeling position or from a freewheeling position into an engagement position in dependence on the direction of a sufficient change in the rotational angle position between the torque-introducing clutch element and the torque-receiving clutch element by means of an actuating force applied to the switching element by an actuator. According to the disclosure, the actuating force is a friction-induced actuating force, which is induced by means of a friction-force pairing between the actuator and a component of the overrunning clutch that is in frictional contact with the actuator and the actuator forms an interlockingly acting actuating stop, by means of which the actuating force acts on the switching element.