Reverse Input Cutoff Clutch With Guided Engagement Release
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Solution Overview
Problem
The reverse input cutoff clutch described in JP 2007-232095A faces difficulties in releasing the state where the output member is prevented from rotating due to a large meshing force when rotational torque is reversely input, making it hard to release the rolling elements from their meshed position.
Innovation Solution
The design incorporates a pressed member, an input member, an output member, and engaging elements with guided surfaces that allow the engaging elements to move radially and frictionally engage with the pressed surface when reverse torque is input, enabling easy release of the locked state by controlling the force distribution between the input and output members.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If rolling elements are meshed into a narrow-width portion of a wedge-shaped space to prevent rotation of the output member, then the blocking function is improved, but the ease of operation deteriorates because it becomes difficult to release the meshed state when large meshing force is generated
Solution Approach 1:
The engaging element is divided into multiple functional portions: a pressing surface for frictional engagement with the pressed member, an input-side engaged portion for engaging the input member, and an output-side engaged portion for engaging the output member. This segmentation allows each portion to perform its specific function independently, enabling the engaging element to be pushed away from the pressed surface by input member engagement, thereby releasing the locked state
Solution Approach 2:
Instead of using the conventional wedge-shaped space that forces rolling elements into a meshed state, this invention inverts the approach by providing a pressed surface on the pressed member and having the engaging element's pressing surface frictionally engage with it. When rotational torque is input to the input member, the engaging element is pushed away from the pressed surface, inverting the force direction to enable easy release of the locked state
2Reliability
If a lock type reverse input cutoff clutch is used to completely block reverse torque, then the blocking function is improved, but the device complexity increases compared to free type clutches
Solution Approach 1:
The pressing surface, input-side engaged portion, and output-side engaged portion are merged into a single integrating member (engaging element). This merging simplifies the device structure by eliminating the need for separate components for pressing and engagement, while still achieving the lock type reverse input cutoff function of completely blocking reverse torque
Solution Approach 2:
The engaging element serves multiple functions simultaneously: it acts as a pressing member through its pressing surface, an input-side engaging member through its input-side engaged portion, and an output-side engaging member through its output-side engaged portion. This multi-functionality reduces the number of components needed in the mechanism
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
This configuration allows for stable switching between locked, half-locked, and unlocked states, preventing the engaging elements from getting stuck and facilitating easy release of the output member's locked or half-locked state, unlike conventional designs.
Implementation Method 1
the engaging element frictionally engage the pressing surface with the pressed surface by pressing the pressing surface against the pressed surface
Data Source
AI summary
The reverse input cutoff clutch comprises a pressed member having a pressed surface, an input member arranged coaxially with the pressed surface and having an input-side engaging portion arranged radially inside the pressed surface, an output member arranged coaxially with the pressed surface and having an output-side engaging portion arranged more radially inside than the input-side engaging portion, and an engaging element arranged radially inside the pressed surface and having a pressing surface facing the pressed surface, an input-side engaged portion that engages with the input-side engaging portions, and an output-side engaged portion that engages with the output-side engaging portion. The output-side engaged portion is configured by a recessed portion, and the interior surface of the recessed portion has a pair of guided surfaces. The output-side engaging portion has a pair of guide surfaces facing the pair of guided surfaces.