Ball Screw Actuator Piston Structure for Stroke Limiting
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Solution Overview
Problem
The existing stroke limiting mechanism in linear motion actuators requires a separate rotation prevention member, which increases weight, size, and complexity, hindering operability and efficiency.
Innovation Solution
The integration of a stepped face on the piston within the linear motion actuator eliminates the need for a separate rotation prevention member by using the piston's design to disperse load and prevent rotation, reducing parts count, weight, and size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate rotation prevention member is mounted on the screw shaft, then the stroke limiting mechanism can be implemented, but the weight and size of the linear motion actuator increase
Solution Approach 1:
The patent combines the rotation prevention member with the piston by integrating a stepped face directly into the piston structure. The stepped face includes a first stepped surface and a second stepped surface that work together to prevent rotation of the screw shaft relative to the piston, eliminating the need for a separate rotation prevention member while maintaining the stroke limiting function.
Solution Approach 2:
The piston is designed to perform multiple functions: it provides the stroke limiting function through the stepped face configuration, prevents rotation of the screw shaft, and maintains the mechanical connection between the screw shaft and the load. This multi-functionality reduces the overall parts count and weight of the linear motion actuator.
2Reliability
If a separate rotation prevention member is mounted on the screw shaft, then the stroke limiting mechanism can be implemented, but the parts count increases
Solution Approach 1:
The rotation prevention member is merged with the piston structure by forming a stepped face directly on the piston body. This integration reduces the parts count by eliminating the separate rotation prevention member while maintaining the necessary stroke limiting and rotation prevention functions through the geometric configuration of the stepped face.
3Reliability
If a separate rotation prevention member is mounted on the end of the screw shaft, then the stroke limiting mechanism can be implemented, but the space required for placing the screw shaft and rotation prevention member increases
Solution Approach 1:
The patent integrates the rotation prevention functionality into the piston structure through the stepped face, eliminating the need for additional space dedicated to a separate rotation prevention member on the screw shaft. The stepped face configuration achieves rotation prevention within the existing piston-screw shaft interface space.
4Reliability
If a separate rotation prevention member is used, then the stroke limiting mechanism can be implemented, but the operability of the linear motion actuator deteriorates
Solution Approach 1:
By integrating the rotation prevention function into the piston structure, the patent reduces the overall mass and moment of inertia of the moving components. This improvement in mass distribution enhances the operability and responsiveness of the linear motion actuator while maintaining the stroke limiting function.
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 parts count reduction, weight reduction, and size reduction while dispersing load effectively, preventing stress concentration and improving operability.
Implementation Method 1
a ball screw device having a screw shaft, a nut, and a plurality of balls
Data Source
AI summary
A linear motion actuator has a ball screw device having a screw shaft, a nut, and a plurality of balls, a piston mounted on one end of the screw shaft, and a stroke limiting mechanism setting an operation starting point in time of the screw shaft toward a first direction pointed by the one end. The nut has one end face directed to the first direction and a protruding part protruding from the one end face.