Planetary Gear Electric Linear Actuator Series Configuration
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional electric linear actuators face limitations in load-carrying capacity due to large screw diameters and require external gear trains for mechanical advantage, which increase complexity and cost.
Innovation Solution
The electric linear actuator incorporates a planetary gear arrangement with a ring gear integrally connected to the piston rod, a sun gear, planet carrier, and retainer with continuous threads, allowing the electric motor, planetary gear arrangement, and piston rod to be disposed in series along a central axis, reducing complexity and enhancing the extension and contraction range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a large diameter screw is used in the screw/nut mechanism, then the load-carrying capacity is improved, but the wall thickness of the associated cylinder becomes thinner which limits the load-carrying capacity
Solution Approach 1:
A planetary gear arrangement is introduced as an intermediary mechanism between the motor and the screw/nut assembly. The ring gear is integrally connected to the piston rod, and the planet gears provide mechanical advantage to amplify the motor's output force, allowing the use of a smaller diameter screw while maintaining high load-carrying capacity
Solution Approach 2:
The invention changes the mechanical advantage parameter by incorporating a planetary gear system with a specific gear ratio. This allows the actuator to achieve higher output force without increasing the screw diameter, thereby maintaining cylinder wall thickness and structural strength
2Force
If external gear trains are used to gain mechanical advantage, then the load-carrying capacity is increased, but the device complexity, space, and cost increase
Solution Approach 1:
The planetary gear arrangement is nested within the actuator housing, with the sun gear connected to the motor output shaft, planet gears mounted on a carrier, and the ring gear integrally connected to the piston rod. This compact nested configuration provides mechanical advantage without requiring external gear trains, reducing overall device complexity and space
Solution Approach 2:
The invention merges the gear reduction function with the linear motion transmission function by integrally connecting the ring gear to the piston rod. This integration eliminates the need for separate external gear trains and reduces the number of components, thereby simplifying the overall device structure
3Force
If the screw feed mechanism surrounds the motor and reduction gear, then the load-carrying capacity is improved, but the expansion and contraction length range along the axis is limited
Solution Approach 1:
The invention transitions from a radial configuration where the screw feed mechanism surrounds the motor to a linear series configuration where the motor, planetary gear arrangement, and piston rod are arranged along a central axis. This dimensional change allows for greater expansion and contraction length range while maintaining load-carrying capacity through the planetary gear mechanical advantage
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 improves the load-carrying capacity and range of motion while reducing the complexity and cost associated with external gear trains, offering a more efficient and cost-effective solution for heavy equipment applications.
Implementation Method 1
a planetary gear arrangement disposed inside the cylinder housing and configured to connect the electric motor to the piston rod. The planetary gear arrangement may include a sun gear, a planet carrier, at least one set of planetary gears that are received in the carrier and engaged with the sun gear, a ring gear engaged with the planet gears
Implementation Method 2
a retainer connected to the planet carrier and having continuous threads on an outer circumferential surface that engage corresponding threads formed on an inner circumferential surface of the cylinder housing
Data Source
AI summary
An electric linear actuator is provided. The electric linear actuator may have a cylinder housing, an electric motor disposed inside the cylinder housing, a piston rod at least partially slidably disposed inside the cylinder housing, and a planetary gear arrangement disposed inside the cylinder housing and configured to connect the electric motor to the piston rod. The planetary gear arrangement may have a ring gear integrally connected to the piston rod. The electric motor, the planetary gear arrangement, and the piston rod may be disposed in series along a central axis of the cylinder housing.