Nested Linear Drive Mechanism for Compact High-Load Actuation
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Solution Overview
Problem
Existing linear actuators with coaxial and parallel drive mechanisms face challenges in reducing size, increasing load capacity, and optimizing space efficiency due to the integration of motor and nut components, necessitating a more compact and efficient design.
Innovation Solution
A linear drive mechanism with a hollow rotor and integrated rolling lead screw, where the rotor drives the screw nut to rotate, converting torque into thrust for axial movement, while using bearings to constrain axial movement and reduce the length of the screw nut, allowing independent processing and cost savings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the motor and nut are arranged in a series structure along the axis, then the linear actuator achieves reliable operation with proper confinement, but the overall size increases due to the housing requirement
Solution Approach 1:
The patent applies nesting by placing the nut inside the motor stator, with the rolling lead screw passing through the rotor. This nested arrangement allows the motor and nut to occupy the same spatial envelope, eliminating the need for an additional housing and reducing the overall actuator size while maintaining reliable operation.
Solution Approach 2:
The patent merges the motor and nut into a single integrated structure where the nut is positioned inside the stator and the rolling lead screw passes through the rotor. This combination eliminates the need for separate housing to confine both components, reducing overall size while maintaining system reliability.
2Length of moving object
If the rolling lead screw is sleeved in the rotor with the screw nut extending axially along the rotor, then the length of the screw and nut is reduced, but the manufacturing complexity increases
Solution Approach 1:
The patent segments the nut into two parts: a stationary portion fixed inside the second bearing and a rotating portion that rotates with the rotor. This segmentation allows the nut to be manufactured as separate components that are easier to produce, while still achieving the reduced axial length when assembled in the integrated structure.
3Strength
If the screw nut is fixed inside the second bearing, then the axial movement is constrained and load capacity increases, but the device complexity increases
Solution Approach 1:
The patent merges the bearing support function with the nut structure by fixing the stationary portion of the nut inside the second bearing. This integration provides axial constraint and load support without requiring additional separate components, thereby increasing load capacity while minimizing the increase in device complexity.
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 mechanism achieves compact size, high load-bearing capacity, and simplified manufacturing with reduced installation space, while maintaining efficient linear motion.
Implementation Method 1
a rolling lead screw sleeved in the rotor. The rolling lead screw includes a central screw rod set on an inner peripheral side of the rotor and passing through the front cover, a screw nut extending axially along the rotor and being fixed inside the second bearing and sleeved on the central screw rod for forming a rotational connection
Data Source
AI summary
The present invention provides a linear drive mechanism, including a housing, a front cover, a rear cover, a stator, and a rotor. The linear drive mechanism further includes a rolling lead screw, a first bearing, and a second bearing. The rolling lead screw includes a central lead screw and a lead screw nut. The rotor includes a hollow rotor body and an annular protrusion thereby driving the central lead screw to achieve linear telescopic motion. Compared with the prior art, the linear drive mechanism of the present invention has a good linear drive effect, which is convenient for reducing the length of the lead screw nut, saving costs, and saving installation space.