Automobile Engine Output Shaft Locking Mechanism with Dual-Finger Alignment
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Solution Overview
Problem
Existing methods for immobilizing the output shaft of a motor vehicle engine, such as using a finger and parking wheel, do not ensure complete locking due to circumferential play, leading to rotor movement and potential vehicle overspeeding during battery recharging, as they allow for slight rotation and vibration-induced torque.
Innovation Solution
A system with two fingers, one engaging without circumferential play and the other with strong play for pre-alignment, along with a pusher mechanism and elastomer ring, ensures complete locking of the output shaft by aligning spaces between teeth and filtering vibrations, allowing for safe immobilization even at non-zero speeds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single finger is used to engage the parking wheel, then the device complexity is reduced, but the locking reliability is insufficient due to circumferential play allowing rotor movement
Solution Approach 1:
The locking mechanism is divided into two independent fingers: a first finger designed to engage without circumferential play for precise locking, and a second finger with strong circumferential play for pre-alignment. This segmentation allows each finger to specialize in one function, resolving the contradiction between reliability and complexity by distributing functions across multiple simple components rather than one complex component.
Solution Approach 2:
The second finger performs a preliminary alignment action by engaging with strong circumferential play to position the parking wheel correctly before the first finger engages. This preliminary action ensures that when the first finger engages without play, the rotor is already properly positioned, achieving reliable locking without requiring a complex single-component mechanism.
2Ease of operation
If the finger width is reduced to enable engagement at non-zero speed, then the ease of operation is improved, but the locking precision deteriorates due to increased circumferential clearance
Solution Approach 1:
The locking function is segmented between two fingers with different dimensional characteristics. The first finger has dimensions optimized for precise engagement without play, while the second finger has larger clearance for easy engagement at motion. This segmentation resolves the contradiction by allowing each finger to have optimized dimensions for its specific function.
Solution Approach 2:
The second finger with larger clearance performs the preliminary engagement action at non-zero speed, bringing the system into a pre-aligned state. This preliminary action with generous clearance enables easy operation, after which the first finger engages with precise dimensions to achieve accurate locking, thus resolving the precision-ease contradiction.
3Manufacturing precision
If the first finger engages without circumferential play, then the locking precision is improved, but the ease of operation deteriorates due to inability to engage at non-zero speed
Solution Approach 1:
The engagement process is segmented into two stages performed by two different fingers. The second finger with large clearance handles the easy engagement at non-zero speed, while the first finger with precise fit handles the final precise locking. This segmentation resolves the contradiction by separating the easy operation function from the precise locking function.
Solution Approach 2:
The system uses the second finger to perform a preliminary engagement action that is easy to execute at non-zero speed. This preliminary action positions the components correctly, enabling the subsequent precise engagement of the first finger without play. The preliminary action thus enables the precise locking to follow, resolving the operation ease-precision contradiction.
4Reliability
If vibration filtering is added to prevent to-and-fro movement, then the reliability is improved, but the device complexity increases
Solution Approach 1:
The vibration filtering function is merged into the existing finger structure by adding an elastomer ring to the first finger. This combines the locking function and vibration damping function into a single integrated component rather than adding a separate vibration isolation system, thus improving reliability while minimizing the increase in device complexity.
Solution Approach 2:
The first finger is made composite by adding an elastomer ring, combining rigid material (finger body) with flexible material (elastomer). This composite structure provides both the precise locking geometry of the rigid finger and the vibration filtering capability of the elastomer, achieving improved stability without significant complexity increase.
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 system effectively prevents rotor movement and torque generation during battery recharging, enhancing safety by ensuring complete locking of the output shaft without wear on components, thus preventing unexpected vehicle movement and prolonging system lifespan.
Implementation Method 1
an elastomer ring between the axis of rotation of the first finger and the first finger so as to filter the vibrations generated by the reactions on the rotor
Implementation Method 2
a pusher capable of performing a translational movement, and the first finger is capable of performing a rotational movement around an axis of rotation
Data Source
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AI summary
The invention relates to a system for blocking the output shaft (16) of the engine of an automobile, of the type that comprises a toothed wheel (10) coaxially mounted on said shaft (16), and a first finger (18) mobile between a shaft (16) releasing position and a shaft blocking position in which said first finger (18) is engaged in a gap formed between two teeth (12, 14) of the wheel. According to the invention, the system includes an alignment means (20) capable of aligning a gap between two teeth (12, 14) of the wheel (10) and the first mobile finger, and the first mobile finger (18) is adapted so as to be inserted into said gap without any substantial circumferential clearance.