Interference-Fit Shaft Lock for Compact High-Torque Holding
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Solution Overview
Problem
Existing shaft locks lack a constructively simple, spatially compact design that efficiently transmits high mechanical moments with minimal rotational clearance and requires significant energy for state transitions, while also being prone to misalignment and heat generation.
Innovation Solution
An interference-fit connection using locking bodies between a radially inner-lying rotor part and a fixed stator part, actuated by a hollow-cylindrical locking ring, allowing for a robust, cost-effective, and energy-free locking and unlocking mechanism with adjustable rotational angle positions and tolerance to misalignments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional shaft locks are used, then rotational movement can be blocked, but the device complexity increases and installation space is consumed
Solution Approach 1:
The shaft lock utilizes the kinetic energy of the shaft itself to drive the locking mechanism. The inertia weights are positioned such that centrifugal force during shaft rotation automatically engages the locking elements, eliminating the need for external power sources or complex control systems while maintaining reliable locking functionality
Solution Approach 2:
The invention extracts and utilizes the kinetic energy already present in the rotating shaft, converting it into the locking action through strategically positioned inertia weights. This eliminates the need for separate actuating mechanisms, reducing overall device complexity while maintaining locking reliability
2Reliability
If conventional shaft locks are used, then rotational movement can be blocked, but significant installation space is required
Solution Approach 1:
The locking mechanism is nested within the existing shaft structure, with inertia weights and locking elements integrated into the shaft's radial and axial dimensions. This nested configuration allows the locking function to be achieved within the existing envelope of the rotating assembly, minimizing additional installation space while maintaining reliable locking
Solution Approach 2:
The invention transitions from conventional axial locking mechanisms to a radial locking approach using centrifugal force. By utilizing the radial dimension and the rotational motion already present in the shaft, the design achieves compact positioning without compromising locking reliability, effectively reducing the volume occupied by the locking mechanism
3Reliability
If conventional shaft locks are used, then rotational movement can be blocked, but energy is consumed during state transitions
Solution Approach 1:
The shaft lock system uses the shaft's own rotational kinetic energy to drive the locking and unlocking actions. The inertia weights automatically position themselves based on rotational speed, engaging locking elements during normal operation and disengaging when rotation stops or reverses, eliminating the need for external actuators and energy input for state transitions
Solution Approach 2:
The locking mechanism is designed to be dynamically responsive to the shaft's rotational state. The inertia weights and locking elements are positioned and dimensioned to automatically engage or disengage based on centrifugal force and rotational speed, allowing the system to transition between locked and unlocked states without additional energy input while maintaining reliable locking during rotation
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 enables efficient transmission of high torques with low installation space, minimal rotational clearance, and no energy consumption in the holding or locking states, while allowing for precise adjustment and contact-free operation, reducing operational heat and misalignment issues.
Implementation Method 1
an interference-fit connection using a plurality of locking bodies between the radially inner-lying rotor part and the fixed and radially outer-lying stator part
Data Source
AI summary
A shaft lock includes a radially inner rotor part that is coaxially connected to a shaft having a rotational axis and a fixed stator part that at least partially encloses the rotor part. In a locking state and in a holding state, an interference-fit connection between the rotor part and the stator part is produced by a plurality of locking bodies, and the interference-fit connection is cancelable by a transition into an unlocking state. To produce the interference-fit connection, each of the plurality of locking bodies are partially engageable in an interference-fit manner in a respective receiving geometry of the rotor part by rotation of a substantially hollow-cylindrical locking ring that coaxially encloses the stator part in a partially radially outer-lying manner.