Linear Motor Cavity Venting for Stable Reciprocating Thrust

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Solution Overview

Problem

The relative movement between the mover and stator assemblies in a linear motor causes pressure differences in the cavities, leading to thrust fluctuation and energy loss due to compression and expansion of spaces.

Innovation Solution

The cavities on either side of the stator assembly are in communication with the external space of the mover assembly, allowing air exchange to quickly adjust pressures and reduce pressure differences, thereby minimizing thrust fluctuation and energy loss.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the linear motor operates with sealed cavities, then the structural integrity is maintained, but thrust fluctuation increases due to pressure differences

Engineering Contradiction:
Improvestructural integrityVSAvoidthrust stability
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The cavity is divided into an upper cavity and a lower cavity that are communicatively connected. This segmentation allows independent pressure management in each cavity while maintaining overall structural integrity, enabling the pressure balancing mechanism to reduce thrust fluctuation without compromising structural strength.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A communication channel is introduced as an intermediary between the upper and lower cavities. This channel enables air flow and pressure equalization between the cavities, acting as a mediator that balances the pressure differences caused by mover assembly movement, thereby reducing thrust fluctuation while maintaining structural integrity.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the cavities are sealed, then the structural integrity is maintained, but energy loss increases due to pressure buildup

Engineering Contradiction:
Improvestructural integrityVSAvoidenergy loss
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The cavity is divided into an upper cavity and a lower cavity that are communicatively connected. This segmentation allows pressure to be managed separately in each cavity, enabling the system to release pressure buildup through the communication channel or breathable valve, thereby reducing energy loss while maintaining structural integrity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The breathable valve extracts excess pressure from the cavities to the external environment. By providing a controlled release mechanism, the system can maintain structural integrity while preventing excessive pressure buildup that would otherwise cause energy loss through inefficient motor operation.

Inventive Principle:
Principle #2Taking out (Extraction)

3Stability of the object's composition

If pressure difference between cavities is large, then structural stability is maintained, but thrust fluctuation increases

Engineering Contradiction:
Improvestructural stabilityVSAvoidthrust fluctuation
Core Design Contradiction:
Stability of the object's compositionVSForce

Solution Approach 1:

A communication channel is introduced as an intermediary between the upper and lower cavities. This channel enables air flow and pressure equalization between the cavities, acting as a mediator that balances the pressure differences caused by mover assembly movement, thereby reducing thrust fluctuation while maintaining structural stability.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system changes the pressure parameter distribution between the upper and lower cavities by enabling communication between them. This allows dynamic adjustment of pressure differences during motor operation, optimizing the balance between structural stability and thrust consistency.

Inventive Principle:
Principle #35Parameter changes

4Ease of manufacture

If the cavities are isolated, then the manufacturing complexity is reduced, but the pressure adjustment speed decreases

Engineering Contradiction:
Improvemanufacturing complexityVSAvoidpressure adjustment speed
Core Design Contradiction:
Ease of manufactureVSSpeed

Solution Approach 1:

The cavity is divided into an upper cavity and a lower cavity with a communication channel between them. This segmentation provides a straightforward manufacturing approach while enabling rapid pressure adjustment through the dedicated communication path, balancing manufacturing ease with performance requirements.

Inventive Principle:
Principle #1Segmentation

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 air exchange mechanism effectively reduces thrust fluctuations and energy loss by quickly equalizing pressures in the cavities, enhancing the stability and efficiency of the linear motor operation.

Implementation Method 1

air in the first cavity and air in the second cavity can be directly or indirectly exchanged with air in the external space of the mover assembly. This helps quickly adjust a pressure in the first cavity and a pressure in the second cavity, and reduce a pressure difference between the first cavity and the second cavity

Methodology Applied
Scientific EffectPressure equalization: Pressure Gradient

Data Source

PatentEP4625786A1Linear motor, electromagnetic suspension, and vehicle
Publication Date: 2025.10.01 BYD CO LTD
  • EP4625786A1 patent drawingFigure 1
  • EP4625786A1 patent drawingFigure 2
  • EP4625786A1 patent drawingFigure 3

AI summary

The present invention discloses a linear motor, an electromagnetic suspension, and a vehicle. The linear motor includes a stator assembly and a mover assembly. The mover assembly is sleeved on an outer periphery of the stator assembly and the mover assembly and the stator assembly define a first cavity and a second cavity. The first cavity and the second cavity are separately located on two sides of an axial direction of the stator assembly for the stator assembly and the mover assembly to move relative to each other. The first cavity is in communication with the second cavity. At least one of the first cavity and the second cavity is in communication with external space of the mover assembly. According to the linear motor in embodiments of the present invention, at least one of the first cavity and the second cavity that are located on the two sides of the stator assembly is in communication with the external space of the mover assembly, so that air in the first cavity and air in the second cavity can be directly or indirectly exchanged with air in the external space of the mover assembly. This helps reduce a pressure difference between the first cavity and the second cavity, thereby reducing thrust fluctuation caused by an impact of the pressure difference on reciprocation of the linear motor.