Integrated Motor Linear Actuator With Direct-Drive Thrust Tube
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing linear actuator designs for robotic welding and automated machine tool systems face challenges in achieving improved positioning accuracy with reduced deflection and tool displacement within a desired weight and size envelope, while maintaining high speed and endurance, and managing thermal performance effectively.
Innovation Solution
The design incorporates an integrated motor linear actuator system with a compact housing that includes a stator, rotor, screw shaft, and nut assembly, where the thrust tube is directly coupled to the nut assembly, enhancing torque and cooling efficiency through a cooling assembly, and providing rotational stability with bushings or bearings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional linear actuator designs are used, then system size and weight are reduced, but positioning accuracy and deflection control deteriorate
Solution Approach 1:
The motor assembly is integrated directly into the actuator housing, merging previously separate components (motor, housing, drive mechanism) into a unified structure. This integration eliminates the need for additional mounting brackets, coupling mechanisms, and external motor mounts, thereby achieving high positioning accuracy through rigid component alignment while maintaining a compact overall size.
Solution Approach 2:
The screw shaft and nut assembly are nested within the motor assembly, which itself is integrated into the actuator housing. This nested arrangement allows the drive components to be housed within the existing structural envelope, providing precise positioning through rigid component support without increasing the external dimensions of the actuator system.
2Productivity
If high speed operation is implemented, then productivity increases, but thermal performance deteriorates
Solution Approach 1:
A cooling assembly is introduced as an intermediary component between the motor assembly and the external environment. This cooling assembly includes cooling channels or heat dissipation structures that facilitate thermal transfer from the motor windings and bearing surfaces, enabling high-speed operation by actively managing the heat generated during rapid actuator cycles.
Solution Approach 2:
The thermal management system modifies the thermal parameters of the motor assembly by introducing active cooling pathways. This allows the motor to operate at higher speeds by continuously removing heat, thereby maintaining acceptable temperature levels even under high-power, high-speed operating conditions that would otherwise cause thermal accumulation.
3Power
If integrated motor design is used, then power-to-weight ratio improves, but manufacturing complexity increases
Solution Approach 1:
The integrated motor linear actuator is divided into distinct modular segments: the actuator housing forming the structural base, the motor assembly as a separate integrated unit, the screw shaft and nut assembly as drive components, and the cooling assembly as a functional add-on. This segmentation allows each module to be manufactured and tested independently using standard processes, reducing overall manufacturing complexity while maintaining the power-to-weight benefits of integration.
Solution Approach 2:
The actuator housing serves multiple functions simultaneously: it provides the structural framework for mounting components, acts as a thermal management pathway for the cooling assembly, and serves as the external interface for the actuator system. This multi-functionality reduces the number of separate parts needed, simplifying manufacturing while achieving high power-to-weight ratio through efficient use of material and space.
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 achieves higher positioning accuracy, reduced weight, increased speed, and improved power-to-weight ratio, along with enhanced thermal management, allowing for more precise and efficient operation in robotic welding and automated systems.
Implementation Method 1
A screw shaft extends within the rotor, along the common longitudinal axis. A nut assembly is engaged with the screw shaft... The nut assembly is configured to convert rotational motion of the rotor about the longitudinal axis into linear motion of the thrust tube along the longitudinal axis
Data Source
AI summary
A linear actuator system having an actuator housing, a motor assembly, a screw shaft, a thrust tube, and a nut assembly. The nut assembly is engaged with the screw shaft and directly coupled with the thrust tube. The nut assembly can define a mechanical fitting for direct physical engagement between the thrust tube and the nut assembly, absent additional load bearing components intervening therebetween. The nut assembly is configured to convert rotational motion of the rotor about the longitudinal axis to linear motion of the thrust tube along the longitudinal axis. A cooling loop can be at least partially embedded, potted or seated within the actuator housing, with a thermally conductive material disposed at least partially about the cooling loop to conduct heat from the actuator housing.