Lead Screw Actuator Re-Engagement to Prevent Nut Binding
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Solution Overview
Problem
Lead screw actuators often become stuck due to the nut lodging against structures during rotation, preventing reverse disengagement and requiring maintenance.
Innovation Solution
Incorporating a shaft with a disengagement portion and an engagement portion, along with a biasing portion that limits movement towards the motor in the uncoupled position, allowing the nut to disengage from the threaded portion and maintain a position adjacent to it, enabling smooth reverse engagement with the threaded portion during opposite rotation direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the nut is allowed to move freely along the threaded rod during rotation, then the actuator can achieve full range of motion, but the nut may lodge against structures and cause the actuator to become stuck
Solution Approach 1:
A biasing portion (spring) is introduced as an intermediary element between the nut and the motor. This spring applies a biasing force to the nut, ensuring it remains engaged with the threaded rod during rotation while preventing it from lodging against the motor or other structures. The spring mediates between the need for free movement and the need to prevent sticking.
Solution Approach 2:
The biasing portion applies a preliminary biasing force to the nut in the direction opposite to potential lodging. By pre-applying this counteracting force, the system prevents the nut from reaching positions where it could lodge against structures, thereby avoiding the stuck condition before it occurs.
2Ease of operation
If the housing is allowed to move toward the motor during rotation, then the actuator can accommodate full travel, but the housing may bind against the motor in the uncoupled position
Solution Approach 1:
The biasing portion acts as an intermediary between the housing and the motor, applying a biasing force that prevents the housing from binding against the motor. This spring element mediates the interaction, allowing full travel while preventing harmful contact.
Solution Approach 2:
The biasing portion provides beforehand cushioning by applying a protective biasing force that prevents the housing from directly contacting and binding against the motor. This pre-applied protective force cushions against potential binding conditions before they occur.
3Ease of repair
If the nut disengages from the threaded portion during operation, then maintenance can be simplified, but the actuator loses motion control capability
Solution Approach 1:
The system dynamically transitions between engaged and disengaged states. The biasing portion ensures the nut remains engaged during motion control operations, but allows easy disengagement when maintenance is needed. This dynamic behavior provides both motion control capability and maintenance simplicity at different times.
Solution Approach 2:
The biasing portion automatically maintains engagement during operation without requiring active control, and allows passive disengagement for maintenance. The system serves itself by automatically re-engaging after disengagement, reducing the need for complex control mechanisms while maintaining motion control capability.
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
Prevents the actuator from becoming stuck, allowing for reliable operation by ensuring the nut can re-engage with the threaded portion, reducing maintenance needs and ensuring smooth motion control.
Implementation Method 1
A biasing portion is slidably engaged with the shaft and is positioned between the housing and the motor, and the biasing portion is configured to limit movement of the housing toward the motor with the housing in the uncoupled position
Implementation Method 2
A motor is coupled to the first end of the shaft and is configured to rotate the shaft about a longitudinal axis of the shaft
Implementation Method 3
A lead screw actuator is a type of actuator that converts rotational motion to linear motion. A lead screw actuator may include a threaded rod coupled to a motor configured to rotate the threaded rod
Data Source
AI summary
An actuator may include a shaft with a first end and a second end. The shaft may include a disengagement portion near the first end and an engagement portion near the second end. The actuator may also include a motor coupled to the first end of the shaft and configured to rotate the shaft about a longitudinal axis of the shaft. A housing may be coupled to the shaft and may be configured to move toward the disengagement portion during rotation of the shaft in a first direction. The housing may have a coupled position, in which the housing is engaged with the engagement portion of the shaft, and an uncoupled position, in which the housing is disengaged from the engagement portion of the shaft and is located adjacent to the disengagement portion of the shaft.