Electric Cylinder Piston-Nut Joint for Misalignment-Tolerant Assembly
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Solution Overview
Problem
The assembly of electric cylinder devices is hindered by the requirement for high accuracy to avoid uneven wear due to radial misalignment between the piston and cylinder, which reduces productivity.
Innovation Solution
The electric cylinder device allows for relative displacement in the radial direction between components such as the piston and cylinder, using mechanisms like elastic deformation and line or point contact to alleviate radial loads, preventing uneven wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high assembly accuracy is required to avoid radial load and uneven wear, then component reliability is improved, but manufacturing productivity deteriorates
Solution Approach 1:
The piston is designed with dynamic adjustment capability in the radial direction through a spherical connection interface between the piston rod end and the nut. This allows the piston to automatically adjust its radial position during operation, transitioning from a static fixed-position design to a dynamic self-adjusting design that compensates for assembly deviations without requiring high precision assembly
Solution Approach 2:
The invention changes the geometric parameters of the connection interface from a conventional fixed cylindrical connection to a spherical connection that allows radial displacement. This parameter change enables the system to tolerate assembly deviations by allowing the piston to move radially within a certain range, thereby reducing the required assembly precision while maintaining component reliability
2Object-affected harmful factors
If strict center position alignment is enforced during assembly, then uneven wear is prevented, but assembly complexity and time increase
Solution Approach 1:
The spherical connection interface between the piston rod end and the nut provides self-aligning functionality, where the piston automatically adjusts its radial position based on the actual assembly conditions. This self-service mechanism eliminates the need for complex alignment procedures and precision measurement tools during assembly, reducing both assembly complexity and time while preventing uneven wear through automatic radial load distribution
3Device complexity
If rigid fixed-position connection is used between piston and nut, then structural simplicity is maintained, but radial load causes uneven wear
Solution Approach 1:
The connection between the piston rod end and the nut is changed from a rigid fixed-position connection to a dynamic spherical connection that allows radial displacement. The piston rod end features a spherical outer surface that fits into a spherical inner surface of the nut, enabling the piston to adjust its radial position dynamically during operation. This maintains structural simplicity while eliminating radial load-induced uneven wear through automatic self-adjustment
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 design prevents uneven wear on components due to assembly deviations and misalignments, enhancing productivity and ease of assembly.
Implementation Method 1
The piston is allowed to undergo relative displacement with respect to the cylinder in the radial direction. On the other hand, a load in the radial direction acting between the piston and the cylinder is alleviated by the relative displacement in the radial direction.
Data Source
AI summary
In an electric cylinder device including a third gear that rotates by receiving rotation of an electric motor and a linear motion conversion mechanism that converts the rotation of the third gear into linear motion of a piston inside a cylinder, a nut, which is a linear motion portion of the linear motion conversion mechanism, and the piston are connected in a state in which relative displacement in a radial direction is allowed.