Park-Lock Tilting Lever Cam Dynamics for Reduced Actuation Force
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Solution Overview
Problem
Existing park-lock devices for vehicle transmissions require springs to maintain the tilting lever in the disengagement position and necessitate higher forces to rotate the cam, risking the tilting lever becoming locked in the engagement position due to contact forces.
Innovation Solution
A double-acting cam system with two cam followers and a spring-mounted drive shaft allows the tilting lever to move between engagement and disengagement positions without a retaining spring, reducing the required force and preventing unintended locking, by using a spring to apply elastic torque to the cam and allowing reversible operation through angular clearance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a spring is used to hold the tilting lever in the disengagement position, then the tilting lever can be maintained in the disengagement position, but the force required to rotate the cam increases and the structure becomes more complex
Solution Approach 1:
The patent applies the dynamics principle by making the cam rotatable on the drive shaft with angular clearance instead of being fixed. This dynamic arrangement allows the cam to automatically adjust its position during rotation, enabling the tilting lever to move between engagement and disengagement positions without requiring a spring to maintain the disengagement position. The angular clearance creates a dynamic system where the cam can tilt relative to the drive shaft, reducing the force needed for rotation while maintaining position stability.
2Stability of the object's composition
If a spring is used to hold the tilting lever in the disengagement position, then the tilting lever can be maintained in the disengagement position, but the device complexity increases
Solution Approach 1:
The patent eliminates the need for a separate spring mechanism by implementing a dynamic cam rotation system. The cam is mounted with angular clearance on the drive shaft, allowing it to tilt and automatically control the tilting lever's position through its rotational movement alone. This dynamic solution replaces what would otherwise require additional springs and mounting mechanisms, thereby reducing device complexity while maintaining position stability.
Solution Approach 2:
The cam serves multiple functions in this invention: it acts as both the actuating element that moves the tilting lever between positions and as the positioning element that maintains the disengagement position without requiring a separate spring. The angular clearance mounting allows the cam to perform both the actuation and positioning functions simultaneously, reducing the number of components needed and simplifying the overall device structure.
3Ease of operation
If high force is applied to rotate the cam, then the tilting lever can be moved to the engagement position, but the tilting lever may become locked in the engagement position due to contact forces
Solution Approach 1:
The dynamic mounting of the cam with angular clearance allows it to tilt and adjust its position during rotation. This dynamic behavior reduces the contact forces between the cam and tilting lever during engagement, preventing the tilting lever from becoming locked. The cam can automatically adjust its angle to minimize binding and friction, ensuring smooth engagement and reliable release without requiring excessive force.
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 provides a compact structure that eliminates the need for retaining springs, reduces the force needed to rotate the cam, and prevents the tilting lever from becoming stuck in the engagement position, ensuring reliable operation and efficient engagement/disengagement.
Implementation Method 1
a spring adapted to apply an elastic torque on the cam about the axis of rotation of the latter
Data Source
AI summary
A park-lock device having a gearwheel connected to a rotating member; a tilting lever with a locking tooth engagable with the gearwheel to prevent rotation thereof, the tilting lever is tiltable about a first axis of rotation between a disengagement and engagement position; and a spring that applies torque on the cam. The cam is mounted about a second axis of rotation parallel to the first axis of rotation and has a first lateral surface portion that cooperates with a first cam follower of the tilting lever. The tilting lever has a second cam follower and the cam has a second lateral surface portion that cooperates with the second cam follower. In a first rotational direction the cam causes the tilting lever to tilt from the disengagement to the engagement position. In a second direction the cam causes the tilting lever to tilt from the engagement to the disengagement position.