Wrap Spring Brake for Spindle Drive Axial Locking
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Solution Overview
Problem
Existing drive devices for movable components in vehicles, such as hatches and doors, lack a compact and efficient braking mechanism to maintain stop positions against unwanted dynamic movements caused by external forces like weight and spring forces, leading to uncontrolled movements.
Innovation Solution
A compact brake device using a wrap spring brake with a switching spring and a brake spring, which are radially frictionally engaged with rotationally symmetrical components, allowing different braking torques in both directions without the need for an actuating device, and are automatically activated by the rotation or non-rotation of the driveshaft.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a centrifugal brake is used to prevent uncontrolled movements, then the braking reliability is improved, but the installation space requirement increases
Solution Approach 1:
The invention extracts the essential braking function from the complex centrifugal brake mechanism and implements it through a simplified wrap spring brake system. The wrap spring brake achieves the necessary braking reliability by using a spring element that automatically engages with the driveshaft, eliminating the need for complex centrifugal mechanisms while reducing installation space requirements.
Solution Approach 2:
The wrap spring brake is designed to actuate automatically based on the rotational state of the driveshaft without requiring external control systems. The spring element self-engages and self-disengages depending on whether the driveshaft is rotating or stationary, providing reliable braking action when needed while maintaining a compact structure.
2Volume of moving object
If a wrap spring brake with switching spring and brake spring is used, then the construction size is reduced, but the complexity of frictional engagement control increases
Solution Approach 1:
The invention uses two wrap springs with different frictional engagement characteristics that dynamically respond to the driveshaft's rotational state. The switching spring provides light frictional engagement that allows rotation in one direction while the brake spring provides stronger frictional engagement to prevent rotation in the opposite direction, creating a dynamic braking system that adapts to operational requirements.
Solution Approach 2:
The braking system employs asymmetric frictional engagement through the two wrap springs, where the switching spring and brake spring have different friction torques tailored to different operational phases. This asymmetric design allows the system to provide appropriate braking force in each direction of rotation while maintaining a compact construction.
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
The solution provides a simple, economical, and compact braking system that effectively maintains the stop position in both movement directions, reducing the construction size and assembly effort while ensuring reliable operation.
Implementation Method 1
the switching spring is radially frictionally engaged at a first rotationally symmetrical component element and the brake spring is radially frictionally engaged at a second rotationally symmetrical component element
Data Source
AI summary
A drive device has a spindle drive having a threaded spindle and a spindle nut arranged on the threaded spindle. The spindle drive is configured to drive a first component element and a second component element so as to be axially movable relative to one another. The spindle drive is reversibly rotatably drivable around an axis of rotation extending coaxial to the threaded spindle by a rotatably driven driveshaft arranged in a housing so as to be fixed with respect to rotation. A brake device prevents axially relative movement of the first component element and second component element relative to one another through axial application of force to the first component element and/or second component element.