Direct-Drive Brake Structure With Low-Energy Actuation
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Solution Overview
Problem
Existing brake devices for direct drive motors in industrial applications are large, energy-inefficient, and costly, with known pin brakes often requiring exposed shafts that are not always available.
Innovation Solution
A compact brake device design featuring a shaft with a brake element and a second member having an opening, where a forcing member pre-tensions a frictional brake surface against another surface, decoupling the normal force for friction from the actuator, and using a simple, energy-efficient actuator to engage and disengage the brake.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a traditional brake device is scaled up to generate high braking torque for direct drive motors, then the braking torque capability is improved, but the device size and energy consumption increase significantly
Solution Approach 1:
The brake device is divided into two independent functional components: a forcing member that applies normal force to create friction braking torque, and a separate actuator that only engages/disengages the brake element. This segmentation allows the braking function to be decoupled from the actuation function, enabling high braking torque with minimal actuator energy consumption.
Solution Approach 2:
The brake element acts as an intermediary between the forcing member and the rotating member. The forcing member applies force to the brake element, which then transfers this force to the rotating member through friction contact, enabling torque transmission without requiring the actuator to directly interact with the rotating member during braking.
2Power
If a traditional brake device is scaled up to generate high braking torque for direct drive motors, then the braking torque capability is improved, but the device size increases
Solution Approach 1:
By separating the forcing member (providing normal force) from the actuator (providing engagement force), the device achieves high braking torque capability in a compact configuration. The actuator can be small since it only needs to move the brake element axially, not generate the full braking torque directly.
Solution Approach 2:
The brake element is configured to move axially (in one dimension) to engage and disengage the brake, while the friction contact occurs in a different dimension (radial direction). This dimensional separation allows compact actuator design while maintaining effective braking capability.
3Device complexity
If friction force is made proportional to clamping force in disc brakes and band brakes, then the braking mechanism is simplified, but the releasing force requirement increases leading to higher energy consumption
Solution Approach 1:
The device separates the function of creating normal force (forcing member) from the function of engaging the brake (actuator). The forcing member continuously applies normal force through elastic deformation, while the actuator only needs to move the brake element axially to engage/disengage, requiring minimal force and energy.
Solution Approach 2:
The forcing member uses its own elastic deformation to continuously maintain the normal force on the brake element without requiring external power input. The elastic element automatically adjusts to maintain contact pressure, making the normal force generation self-sustaining.
4Volume of moving object
If known pin brakes are used, then compact design is achieved, but they require exposed shafts that are not always available in direct drive configurations
Solution Approach 1:
The brake element can engage with the rotating member in multiple ways: through axial movement to contact friction surfaces, or through the engaging structure that can interact with various rotor configurations (exposed shafts, enclosed rotors, hub configurations). This makes the brake device universally applicable to different direct drive motor types.
Solution Approach 2:
The brake element is designed with dynamic engagement capability through the engaging structure that can selectively engage or disengage from the rotor. This dynamic engagement mechanism allows the brake to adapt to different rotor configurations and operational requirements, enhancing versatility.
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 design provides effective braking with reduced energy consumption, compact size, and cost-effectiveness, suitable for braking traction wheels in drive units with electric motors, and can be integrated into industrial devices like AGVs and robots.
Implementation Method 1
a forcing member pre-tensioned to force the second frictional brake surface against the first frictional brake surface
Data Source
AI summary
A brake device including a first device having a shaft; a brake element having a first frictional brake surface and an engageable structure; a second device rotatable relative to the first device about a rotation axis, the second device including a second member having an opening, a second frictional brake surface, and a forcing member pre-tensioned to force the second frictional brake surface against the first frictional brake surface; and an actuator connected to the first device, the actuator including an engaging structure movable between a disengaged position, and an engaged position to brake relative rotation between the first device and the second device about the rotation axis; wherein the shaft is concentric with the rotation axis and passes through the opening.