Robot Brake Surfaces With Low Friction for Oil-Resistant Torque
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Solution Overview
Problem
Industrial robot brake devices are sensitive to oil and grease contamination, leading to reduced braking torque and safety concerns, and require complex, bulky, or expensive designs to mitigate these issues, while also facing challenges with high impact forces at high speeds.
Innovation Solution
A brake device with a low dynamic friction coefficient between its frictional surfaces, achieved through material selection or lubrication, decouples the normal force creating friction from the actuator, using a high pressing force to compensate for contamination and featuring a resilient engagement mechanism to reduce impact forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional brake devices with high friction coefficients are used, then high braking torque can be generated, but the brake device becomes highly sensitive to oil and grease contamination which drastically reduces braking performance
Solution Approach 1:
The patent fundamentally changes the friction coefficient parameter from conventional high values (0.3-0.5) to a very low value (0.05-0.15). This parameter inversion makes the brake device insensitive to additional lubricant contamination because the friction surfaces are already in a low-friction state, eliminating the drastic performance reduction seen in conventional brakes when contaminated by oil or grease.
2Object-affected harmful factors
If design efforts are made to reduce ingress of friction reducing substances to the friction materials, then contamination resistance is improved, but the design becomes more complex, bulky and expensive
Solution Approach 1:
The patent extracts and removes the need for complex protective measures against contamination. By fundamentally changing the friction characteristic to low friction, the invention eliminates the requirement for seals, shields, and other protective structures that would otherwise be needed to prevent contamination, thereby simplifying the design while achieving contamination resistance.
3Use of energy by moving object
If pin brakes are used to decouple the normal force from the actuator, then the brake device becomes more compact and energy efficient, but high impact forces are generated between the actuator pin and brake disc
Solution Approach 1:
The patent applies beforehand cushioning by introducing a resilient element between the actuator pin and brake disc that absorbs and dampens impact forces. This cushioning element is pre-installed to prevent damage from impact forces while maintaining the compact pin brake design and low energy consumption characteristics.
4Reliability
If a high pressing force is applied to compensate for low dynamic friction coefficient, then braking torque is maintained even with contamination, but the force device must be designed for higher loads
Solution Approach 1:
The patent replaces the conventional mechanical friction-based braking system with a low-friction surface system where braking is achieved through a different mechanism. The low dynamic friction coefficient surfaces (0.05-0.15) allow for controlled braking with reduced sensitivity to contamination, and the pressing force is optimized rather than maximized, balancing reliability with reasonable force requirements.
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 brake device is less sensitive to contaminants, provides reliable and safe operation, and is suitable for high-speed and high-torque applications with a compact and cost-effective design, maintaining effective braking performance even in the presence of lubricants.
Implementation Method 1
a dynamic friction coefficient between the first frictional brake surface and the second frictional brake surface is less than 0.15, or less than 0.1; and wherein the pressing force is dimensioned with respect to the dynamic friction coefficient
Data Source
AI summary
A brake device including a first device; a brake element having a first frictional brake surface and an engageable structure; a second device movable relative to the first device; a second frictional brake surface; a force device arranged to press the first frictional brake surface and the second frictional brake surface against each other with a pressing force; and an actuator connected to the first device, the actuator including an engaging structure movable between a disengaged position not engaging the engageable structure, and an engaged position engaging the engageable structure to brake relative motion between the first device and the second device; wherein a dynamic friction coefficient between the first frictional brake surface and the second frictional brake surface is less than 0.3, such as less than 0.15, or less than 0.1; and wherein the pressing force is dimensioned with respect to the dynamic friction coefficient.