Nested Electric Motor Linear Actuator Design
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Solution Overview
Problem
Hydraulic actuators in heavy machinery are complex and prone to failure, requiring frequent maintenance and operator attention, while existing electric linear actuators have limited range of motion due to motor placement and size constraints.
Innovation Solution
The design of a compact electric linear actuator with the electric motor housed within the actuator rod, allowing for greater retraction and extended range of motion, and incorporating a puck and transmission system for efficient linear motion, reducing mechanical complexity and increasing operational efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the electric motor is placed inside the actuator rod, then the range of motion is extended and retraction is improved, but the mechanical complexity increases
Solution Approach 1:
The electric motor is nested within the actuator rod, with the motor housing positioned inside the rod structure. This allows the motor to be integrated into the existing actuator geometry without significantly increasing external dimensions, enabling extended range of motion while containing mechanical complexity within the nested structure.
Solution Approach 2:
The motor is positioned axially within the rod rather than radially or externally, utilizing the longitudinal dimension of the rod to accommodate the motor. This dimensional arrangement allows the motor shaft to extend toward the piston end, enabling the drive mechanism to reach the piston for direct coupling without increasing radial footprint.
2Measurement precision
If hydraulic actuators are used for positioning heavy machine components, then precision and control are improved, but maintenance requirements and operator attention increase
Solution Approach 1:
The hydraulic actuation system is replaced with an electric motor-driven mechanism. The motor couples directly to the piston through the rod, eliminating hydraulic fluid, seals, and piping while maintaining precise positioning control through electrical actuation. This substitution reduces maintenance requirements associated with hydraulic fluid levels, contamination, and seal leakage.
Solution Approach 2:
The electric motor provides self-contained actuation within the rod structure, requiring no external hydraulic fluid reservoirs, pumps, or cooling systems. The motor's integrated position within the rod allows it to self-regulate its operation without external hydraulic system intervention, reducing the need for operator monitoring and maintenance of hydraulic fluid characteristics.
3Speed
If a threaded spindle and nut mechanism is used, then linear motion is achieved, but the motor occupies significant space limiting rod retraction
Solution Approach 1:
The threaded spindle mechanism is extracted from the traditional configuration where the nut moves along an external spindle. Instead, the motor and its drive mechanism are taken inside the rod, with only the essential driving components remaining. This extraction allows the rod to retract more fully since the bulk of the mechanism is contained within the rod volume rather than occupying external space.
Solution Approach 2:
Rather than having the nut travel along a fixed external spindle, the design inverts the arrangement by placing the motor and spindle inside the rod, with the drive mechanism oriented to push the piston directly. This inversion allows the rod to retract into the housing more completely, as the motor housing provides the structural boundary rather than an external spindle assembly.
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 compact design enhances mechanical simplicity, reduces part failure, and provides a greater range of motion, making it suitable for various mechanical applications with reduced operational complexities and costs.
Implementation Method 1
An electric linear actuator utilizes one or more electric motors to generate torque. The generated torque is then converted, via one or more mechanisms of the electric linear actuator, into translational motion in a substantially straight-line path.
Data Source
AI summary
An electric linear actuator includes include a housing, a puck, an actuator rod, and an electric motor. The puck is contained within the housing and configured for substantially linear motion, within the housing. The actuator rod is capable of being contained, at least in part, within the housing and configured to actuate, in a substantially linear fashion, in response to substantially linear motion of the puck. The electric motor is disposed within the rod and configured to provide mechanical force to cause the substantially linear motion of the puck, within the housing.