Robot Joint Brake Shoe with Piezo Release for Low-Wear Locking
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Solution Overview
Problem
Existing safety brake systems for rotating shafts are complex, large, heavy, energy-intensive, and prone to rapid wear due to point contacts, making them unsuitable for compact and efficient applications like robot arm joints.
Innovation Solution
A compact safety brake system utilizing a spring-activated brake shoe and a piezo actuator to counteract the spring, eliminating the need for a ball carrier rotor or brake disc, with a brake shoe design that provides a larger contact surface and self-lubricating materials to reduce wear and heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a solenoid is used as the switch-off device to activate the brake, then the brake can be reliably activated, but the energy consumption increases and heat dissipation occurs
Solution Approach 1:
The patent replaces the solenoid (electromagnetic actuator) with a piezoelectric actuator to drive the brake shoe. The piezoelectric actuator converts electrical energy to mechanical displacement more efficiently, reducing energy consumption and heat generation while maintaining reliable brake activation capability.
Solution Approach 2:
The patent changes the actuation mechanism from electromagnetic to piezoelectric, fundamentally altering the energy conversion parameters. The piezoelectric effect provides higher efficiency in converting electrical energy to mechanical work, thereby reducing overall energy consumption and heat dissipation of the brake system.
2Reliability
If balls with point contacts are used for locking the shaft, then the locking function is achieved, but rapid wear occurs
Solution Approach 1:
The patent changes the contact interface from point contact (balls) to surface contact (brake shoe against shaft). This local quality change distributes the contact pressure over a larger area, significantly reducing wear rate and extending the service life of the braking components while maintaining effective locking capability.
Solution Approach 2:
The brake shoe is designed with composite material structure, combining materials with high friction coefficients and wear resistance. This allows the brake shoe to maintain effective friction-based locking while enduring prolonged operational cycles with minimal wear.
3Reliability
If a ball carrier rotor and brake disc are included in the system, then the braking function is achieved, but the system becomes complex and heavy
Solution Approach 1:
The patent extracts and eliminates unnecessary components (ball carrier rotor, brake disc) from the traditional brake system. By using a simplified friction-based braking mechanism where the brake shoe directly contacts the shaft, the system achieves reliable braking function with significantly reduced structural complexity and weight.
Solution Approach 2:
The patent merges multiple components into a more integrated structure. The brake shoe is positioned to directly contact the shaft surface, eliminating the need for separate ball carrier rotors and brake discs. This merging of functions reduces the number of parts and simplifies the overall system architecture.
4Duration of action of stationary object
If a larger contact surface is used for the brake shoe, then wear is reduced, but the axial dimension increases
Solution Approach 1:
The patent optimizes the brake shoe geometry to distribute contact area across different dimensions. By carefully designing the radial and axial extents of the brake shoe, the system achieves sufficient contact surface area for wear reduction while constraining the axial dimension to meet compactness requirements through dimensional optimization.
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 results in a lightweight, energy-efficient brake system with reduced wear and improved performance, capable of fast switching and fail-safe operation in emergency situations, suitable for compact designs like robot arm joints.
Implementation Method 1
a constant-on braking device (2) activated by a spring (3)
Implementation Method 2
a switch-off device (4) for the braking device (2) that counteracts the spring (3), so that the shaft (1) can be unlocked
Implementation Method 3
self-lubricating materials to reduce wear and heat dissipation
Data Source
AI summary
The invention relates to a safety brake system comprising a round rotatable shaft locked with a constant-on braking device activated by a spring and a switch-off device for the braking device that counteracts the spring, so that the shaft is unlocked and can rotate when the switch-off device is active. According to the invention the constant-on brake device comprises a brake shoe pushed against the shaft by the spring and the switch-off device is a piezo actuator that counteracts the spring. The brake system is normally constant on since the spring pushes the brake shoe against the shaft. When the shaft needs to rotate the piezo actuator counteracts the spring, thus releasing the brake shoe from the shaft. In case of an emergency or when the shaft needs to be locked, the power to the piezo activator is shut off and the spring pushes the brake shoe against the shaft to stop any rotation.