Linear Drive Passive Unit Mass Reduction via Lateral Guidance
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Solution Overview
Problem
Existing linear drives face challenges in achieving high drive forces with minimal passive unit mass, while maintaining a reduced overall structural size and stable lateral guidance, due to limitations in the design of the passive unit and lateral guidance mechanisms.
Innovation Solution
The linear drive employs a lateral guidance plate integrated into the reflux element, which engages in a guiding gap to provide symmetric force conditions, and uses a thin toothed plate with a reflux element to increase magnetic flow cross-section, allowing for a drastic mass reduction of the passive unit while maintaining high drive forces. Additionally, an air bearing supports the passive element, and the guidance gap is formed by a secondary air bearing for reduced friction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If the passive unit is made thinner to reduce mass, then the acceleration and force-to-mass ratio improve, but the magnetic flow cross-section decreases causing drive force loss
Solution Approach 1:
The patent extends the magnetic circuit in the lateral dimension by adding a reflux element that runs parallel to the active unit. This creates an additional path for magnetic flux, effectively increasing the magnetic flow cross-section without increasing the thickness of the passive unit's toothed plate, thus maintaining drive force while reducing mass
Solution Approach 2:
The magnetic circuit is segmented into multiple parallel paths: one through the toothed plate and another through the reflux element. This segmentation allows the magnetic flux to be distributed across multiple channels, effectively increasing the total cross-section for magnetic flow while keeping individual components thin and lightweight
2Measurement precision
If lateral guidance is added to stabilize the passive unit, then positioning precision improves, but the overall structural size and mass increase
Solution Approach 1:
The reflux element serves multiple functions simultaneously: it provides a return path for magnetic flux (solving the drive force problem), acts as a lateral guide for the toothed plate (solving the positioning precision problem), and serves as a structural support element. This multi-functionality eliminates the need for separate lateral guidance components, maintaining positioning precision without increasing overall structural size
Solution Approach 2:
The lateral guidance function is merged with the reflux element structure. The reflux element is positioned and dimensioned to simultaneously close the magnetic circuit and provide lateral guidance for the toothed plate, combining two previously separate functions into a single integrated component
3Speed
If air bearing is used to reduce friction, then movement smoothness and speed improve, but the complexity of the bearing unit increases
Solution Approach 1:
The patent employs air bearings to support the passive unit, allowing it to move smoothly over the active unit with minimal friction. Compressed air is supplied through nozzles to create a thin air film between the active and passive units, enabling high-speed movement and precise positioning while keeping the bearing mechanism relatively simple
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 enables high acceleration and precise positioning with a significantly reduced overall weight, achieving a high force-to-mass ratio and improved structural stability, making it suitable for automation units with enhanced accuracy and reduced susceptibility to torques and transverse forces.
Implementation Method 1
a fixed active unit (1) containing coil bodies (2) to generate an alterable magnet flow
Implementation Method 2
a bearing unit (15) permitting a low friction movement between the active and passive units
Data Source
AI summary
The invention relates to a linear drive having a stationary active unit (1), a stationary return flow element (11), a movably mounted passive unit in the form of a thin tooth rack (10) and a bearing unit (15), which allows the relative movement between the active unit and the passive unit. A lateral guidance plate (30) is attached to the tooth rack (10), extends at an angle with respect to the plane of the tooth rack (10) into a guide gap (31) and is guided there, the guide map (31) running in the return flow element (11) or in the active unit (1).