Robot Joint Brake Assembly With Curved Braking Star Webs
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Solution Overview
Problem
Existing braking devices for robot arms, particularly in human-robot collaboration, face challenges with high rotational speeds leading to material failure due to pronounced elastic deformation and reduced service life.
Innovation Solution
A braking device with a rotationally fixed braking star and a bolt, where the braking star features radially projecting webs with inwardly curved impact surfaces and recesses, distributing forces to reduce leverage effects and minimize deformation, combined with a suitable material pairing for enhanced energy absorption and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a spring-actuated head bolt engages with radially projecting prongs of a braking star at high rotational speeds, then emergency stop function is achieved, but pronounced elastic deformation occurs leading to material failure
Solution Approach 1:
The impact surface of the web is curved inwards with respect to the direction of rotation, forming an arc-shaped surface that matches the rotational path of the bolt. This curvature allows the bolt to engage smoothly along a curved trajectory, distributing the impact forces more evenly across the web structure and reducing peak stresses that cause elastic deformation and material failure.
Solution Approach 2:
The impact surface extends in the radial direction beyond the distance between the axis of the rotor and the axis of the bolt, creating a three-dimensional engagement geometry. This radial extension allows forces to be introduced into the web in multiple directions (radially outward and longitudinally), converting concentrated impact loads into distributed stress patterns that reduce leverage effects and prevent material failure.
2Reliability
If the impact surface extends radially beyond the bolt axis distance, then forces are distributed to reduce leverage effects, but the web structure becomes more complex
Solution Approach 1:
The braking star is divided into multiple webs that are radially projecting from the rotor axis. Each web is independently structured with its own impact surface, allowing the load to be distributed across multiple separate structural elements. This segmentation reduces the leverage effect on any single web while maintaining overall structural simplicity through modular repetition of the web design.
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 significantly increases the service life of the braking device by reducing the risk of mechanical failure and allowing for faster speed reduction during emergency stops, while maintaining a lightweight and compact design suitable for human-robot collaboration.
Implementation Method 1
the forces are distributed in the web in such a way that elastic energy dissipation takes place, which, viewed in the radial direction, exerts a reduced leverage effect on the web acting as a bending beam
Data Source
AI summary
A braking device for a drive device of a joint between two links of a robot arm including a brake activating device and a locking element, wherein the brake activating device is designed to bring the locking element into engagement with a rotor of the drive device as required in order to halt rotation of the rotor, the locking element being designed as a bolt and the braking element being designed as a braking star with webs which have a defined impact surface for the bolt.