Brushless Direct-Drive Linear Servo Actuator With Integrated Position Feedback
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Solution Overview
Problem
Existing brushless direct drive linear actuators for harsh application environments, such as internal combustion engines, face challenges with accuracy, reliability, and cost due to mechanical motion conversion mechanisms, high temperature sensitivity, and brush motor limitations, which result in reduced service life and increased manufacturing complexity.
Innovation Solution
A brushless direct drive linear servo actuator with a stator composed of integrally encapsulated armatures, a mover with magnets, and integral position feedback, where the stator and mover are arranged in mirror symmetry, reducing friction and mechanical clearances, and using wear-resistant bushings to enhance load resistance and heat dissipation, allowing for precise position control without mechanical conversion deviations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If mechanical motion conversion mechanisms (gears, cam mechanisms, screw mechanisms) are used to convert rotary motion to linear motion, then linear thrust can be generated with appropriate stroke, but manufacturing accuracy requirements increase, clearance amplification occurs, and reliability decreases due to mechanical wear and high temperature sensitivity
Solution Approach 1:
The patent replaces mechanical motion conversion mechanisms (gears, cam mechanisms, screw mechanisms) with a direct linear motor structure where the mover assembly directly generates linear motion through electromagnetic forces. The stator assembly with armatures and the mover assembly with magnets interact to produce direct linear thrust without mechanical conversion, eliminating wear, clearance amplification, and mechanical failure points while maintaining the required linear thrust output
Solution Approach 2:
The patent extracts and removes the mechanical motion conversion mechanisms (gears, cam mechanisms, screw mechanisms) from the system entirely. By taking out these intermediate mechanical components, the design achieves direct linear motion generation through electromagnetic interaction between the stator and mover assemblies, eliminating the reliability issues associated with mechanical wear and high-temperature sensitivity
2Power
If mechanical motion conversion mechanisms are used, then linear motion can be achieved, but manufacturing accuracy and assembly positioning accuracy requirements increase significantly
Solution Approach 1:
The patent replaces mechanical motion conversion mechanisms with a direct linear motor structure where the stator and mover assemblies interact through electromagnetic fields. This substitution eliminates the need for high-precision mechanical gears, cam mechanisms, or screw mechanisms, thereby reducing manufacturing and assembly positioning accuracy requirements while maintaining linear motion capability
Solution Approach 2:
The patent extracts mechanical motion conversion mechanisms from the system, removing the source of high manufacturing precision requirements. The direct electromagnetic interaction between stator armatures and mover magnets enables linear motion without intermediate mechanical components that would require tight tolerances and precise assembly positioning
3Ease of manufacture
If brush motors are used to reduce cost, then manufacturing cost decreases, but service life is limited due to brush abrasion
Solution Approach 1:
The patent replaces the brush motor's mechanical contact system (brushes and commutator) with a brushless direct current motor structure. The electromagnetic interaction between the stator armatures and mover magnets occurs without physical contact, eliminating brush abrasion and extending service life while maintaining cost-effectiveness through simplified construction and reduced maintenance requirements
Solution Approach 2:
The patent extracts and removes the brush and commutator components from the motor system. By taking out these consumable parts that require frequent replacement due to abrasion, the design achieves extended service life through contactless electromagnetic actuation while maintaining manufacturing cost efficiency
4Duration of action of moving object
If electronic controllers with commutation and actuator control are added to use brushless motors, then service life increases, but electronics cost and device complexity greatly increase
Solution Approach 1:
The patent extracts and removes the need for complex electronic controllers with commutation circuits. By designing a brushless motor structure where the stator armatures and mover magnets directly interact to produce linear motion, the system eliminates the requirement for electronic commutation and complex control electronics, thereby reducing device complexity and cost while maintaining extended service life
Solution Approach 2:
The patent replaces the electronic control system with a simplified electromagnetic direct drive mechanism. The stator armatures and mover magnets interact through electromagnetic fields to produce direct linear motion without requiring electronic commutation or complex actuator control, achieving service life extension through brushless operation while minimizing electronics cost and device complexity
5Measurement precision
If position signal sensors are separately arranged at the output end, then position feedback can be obtained, but electromagnetic interferences affect accuracy and structural arrangement becomes challenging
Solution Approach 1:
The patent merges the position feedback function directly into the mover assembly structure. The position signal emitter is integrated on the mover assembly, which moves with the linear motion, eliminating the need for separate sensors at the output end. This integration reduces electromagnetic interference and simplifies structural arrangement while maintaining position feedback accuracy
Solution Approach 2:
The patent embeds the position signal emitter within the mover assembly structure. The emitter is nested into the moving component itself, allowing position feedback to be obtained directly from the moving part without external sensors. This nesting approach reduces electromagnetic interference and simplifies the overall structural arrangement
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 high accuracy, reliability, and reduced production costs by minimizing friction, eliminating mechanical conversion errors, and improving heat dissipation, making it suitable for large-scale manufacturing applications in harsh environments.
Implementation Method 1
A brushless direct drive linear servo actuator comprises a stator, a mover and a housing, wherein the stator comprises a pair of armatures arranged in mirror symmetry at both sides of the mover... each armature comprises a core, an insulation and a wire coil... The mover comprises a frame and a magnet...
Data Source
AI summary
The present disclosure provides a brushless direct drive linear servo actuator, comprising: a stator, a mover and a housing, wherein the stator is a pair of armatures arranged in mirror symmetry at both sides of the mover, the housing integrally encapsulates the stator and forms a cavity for the mover at the mover, and the mover has an output end protruding out of the housing and is linearly movable along a direction of the output end. A displacement signal emitter is provided at a side of the mover, and a signal receiver is provided within a cover arranged outside the housing on said side for detecting a displacement signal emitted by the emitter of the mover. The actuator of the present disclosure is characterized by high reliability, high accuracy and low cost.