Ball Screw End Stop Assembly to Prevent Self-Locking Jamming
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Solution Overview
Problem
Conventional ball screw drives face jamming issues due to self-locking effects when using axial end stops, requiring high loosening torque, and existing solutions like radial stop disks or splines are complex and difficult to install.
Innovation Solution
A one-piece bearing/stop element with two anti-rotation devices, allowing adjustable and fixed angular positioning of the threaded spindle and featuring a radial stop element that interacts with a counter-stop surface on the spindle nut, reducing system complexity and assembly effort.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If an axial end stop (flange) is used to limit the travel of the spindle nut, then the travel limitation is achieved, but the self-locking effect causes the spindle nut and threaded spindle to jam, requiring very high loosening torque
Solution Approach 1:
The invention transitions from axial end stopping to radial end stopping. The radial stop element is arranged radially outward from the threaded spindle, with a stop surface that interacts with a counter-stop surface on the spindle nut. This dimensional change from axial to radial direction eliminates the jamming effect caused by self-locking while maintaining effective travel limitation.
2Ease of operation
If a radial stop washer is connected to the spindle and a projection is provided on the spindle nut, then the rotational movement is stopped, but the assembly effort and system complexity increase
Solution Approach 1:
The invention merges the radial stop element with the bearing element into a single integrated component. The radial stop element is formed as one piece with the bearing element, eliminating the need for separate assembly steps and reducing system complexity while maintaining the anti-rotation function.
Solution Approach 2:
The bearing element is designed to serve multiple functions simultaneously: it acts as both a bearing element and a radial stop element. This multi-functionality reduces the number of components needed and simplifies the overall assembly process.
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 jamming by allowing smooth end-stop engagement without angular momentum issues, simplifying installation and reducing the required loosening torque, thus enhancing the operational efficiency of ball screw drives.
Implementation Method 1
The bearing element is positively connected to a receptacle and features two anti-rotation devices. The first anti-rotation device is designed such that an angular relationship between the threaded spindle and the bearing/stop element can be adjusted and subsequently fixed by friction.
Implementation Method 2
The first anti-rotation device is designed such that an angular relationship between the threaded spindle and the bearing/stop element can be adjusted and subsequently fixed by friction.
Data Source
Figure 1~3b
AI summary
A ball screw drive (10) comprises a threaded spindle (12) and a spindle nut (14), which coaxially at least partially surrounds the threaded spindle (12) and has a stop on an axial end face (18). A plurality of balls can rotate in the space (16) between the threaded spindle (12) and the spindle nut (14). A radial stop element (22) is force-fitted to the threaded spindle (12) and is designed to interact with the complementary axial end face (18) of the spindle nut (14). A bearing element is provided for receiving a first longitudinal end of the spindle nut (12). According to the invention, the radial stop element (22) and the bearing element are combined as a one-piece bearing/stop element (24) and have two anti-rotation features (26, 28).