Electromagnetic Shaft Brake Assembly for Stable Lens Focus
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Solution Overview
Problem
In imaging assemblies, maintaining the focus of a lens is challenging due to power consumption requirements for electromagnetic actuator shafts, especially in mobile devices, and exposure to vibrations and thermal changes in large-scale assemblies, which can compromise lens position.
Innovation Solution
An electromagnetic braking assembly comprising a braking coil, a braking magnet, and a braking spring that maintains the actuator shaft's position by exerting pressure when electricity is applied and allowing movement when it's not, thereby reducing power consumption and stabilizing the lens during vibrations and thermal changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If continuous current is applied to the actuator coil to maintain the actuator shaft position, then the lens focus position is maintained, but power consumption increases
Solution Approach 1:
The braking coil receives periodic or pulsed current rather than continuous current. The controller applies current to the braking coil only when needed to maintain the braking magnet in the first position, allowing the actuator shaft to remain stationary without continuous power consumption. This periodic activation resolves the contradiction by providing position maintenance only when necessary.
Solution Approach 2:
The braking spring provides a mechanical self-service mechanism that continuously exerts force on the braking magnet to maintain it in the first position. This mechanical system works passively without requiring continuous electrical power, allowing the actuator shaft to maintain its position through the combined effect of the spring force and intermittent electromagnetic braking.
2Use of energy by moving object
If the actuator shaft is allowed to move freely without braking pressure, then power consumption is reduced, but the lens focus position becomes unstable under vibration and thermal changes
Solution Approach 1:
The braking spring预先 applies a stabilizing force to the actuator shaft through the braking magnet, creating a preliminary counter-action against potential disturbances such as vibration and thermal changes. This pre-applied mechanical constraint ensures position stability without requiring continuous electromagnetic power, resolving the contradiction between stability and power consumption.
3Reliability
If the braking spring continuously exerts pressure on the actuator shaft to prevent movement, then position stability is improved, but the actuator shaft cannot engage in linear movement when needed
Solution Approach 1:
The braking system transitions from a static continuous-pressure state to a dynamic intermittent-pressure state. The braking magnet can move between the first position (where the spring exerts stabilizing pressure) and the second position (where the spring does not exert pressure, allowing linear movement). This dynamic positioning resolves the contradiction by adapting the braking force to the operational needs of the actuator shaft.
Solution Approach 2:
The braking magnet serves as an intermediary element between the braking spring and the actuator shaft. It transmits the stabilizing force from the spring to the shaft when in the first position, but can be moved to the second position to disconnect this force transmission, allowing the shaft to move freely. This intermediary mechanism enables both stability and movement capability.
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 braking assembly effectively maintains the actuator shaft's position without continuous power, conserving energy in mobile devices and stabilizing the lens under various conditions, ensuring optimal image quality.
Implementation Method 1
a braking coil to which electricity may be applied to produce a magnetic field, a braking magnet that is capable of changing position as it interacts with the magnetic field
Data Source
AI summary
An electromagnetic braking assembly for maintaining an actuator shaft in position, and methods for utilizing the same, are provided. The actuator shaft may include an object, e.g., an imaging lens, which is movable in accordance with movement of the shaft. The braking assembly may include a braking coil to which electricity may be applied to produce a magnetic field, a braking magnet capable of changing position as it interacts with the magnetic field, and a braking spring coupled with the magnet such that the spring changes position as the magnet changes position. When the braking spring is in one position, the spring exerts pressure on the actuator shaft substantially preventing the shaft from engaging in linear movement and thus maintaining the shaft in position. When the actuator shaft is in another position, the braking spring does not exert pressure on the shaft permitting the shaft to engage in linear movement.