Rail Brake Actuator With Self-Locking Worm Gear Force Holding
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Solution Overview
Problem
Existing parking brake systems for rail vehicles face challenges in maintaining a specified braking force consistently due to factors like complexity and reliability, particularly in the context of temperature variations affecting brake components.
Innovation Solution
An electromechanical brake system with a brake actuator that generates an electric brake-force signal, utilizing a self-locking worm gear arrangement to maintain a set force value, and includes a backup power unit for uninterrupted operation, ensuring the brake remains engaged as needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional pneumatic brake systems are replaced by electro-mechanical brake actuators, then modernization and new opportunities are achieved, but reliability is compromised due to difficulty in maintaining particular clamping force
Solution Approach 1:
The worm gear arrangement is self-locking, meaning it automatically maintains the clamping force without requiring external power or control systems. The mechanical self-locking property prevents back-driving, ensuring the brake maintains its set force value independently of power supply status.
Solution Approach 2:
The patent replaces the traditional pneumatic system with an electro-mechanical actuator that uses a worm gear mechanism. This mechanical substitution eliminates the need for compressed air while providing reliable force maintenance through the self-locking property of the worm gear.
2Reliability
If additional locking mechanisms are added to maintain braking force, then reliability is improved, but device complexity increases
Solution Approach 1:
The worm gear arrangement serves dual functions: it transmits the actuating force from the electric motor to the pressing member, and simultaneously provides self-locking to maintain the clamping force. This multi-functionality eliminates the need for separate locking mechanisms.
Solution Approach 2:
The self-locking worm gear automatically maintains the braking force without requiring additional locking devices or complex control systems. The mechanical property of the worm gear itself provides the locking function, simplifying the overall device structure.
3Reliability
If continuous power supply is used to maintain brake engagement, then braking force consistency is improved, but energy consumption increases
Solution Approach 1:
The electric motor operates periodically to adjust the pressing member position, and once the desired clamping force is achieved, the motor can be de-energized. The self-locking worm gear maintains the force without requiring continuous power supply, enabling periodic rather than continuous energy consumption.
Solution Approach 2:
The self-locking mechanism maintains the braking force passively without requiring continuous energy input. The mechanical self-locking property allows the system to hold the clamping force indefinitely without power consumption, eliminating the need for continuous electrical power supply.
4Measurement precision
If complex control systems are implemented to adjust braking force, then braking precision is improved, but device complexity increases
Solution Approach 1:
The system includes a force sensor that detects the actual braking force and provides feedback to the control unit. The control unit compares the detected force with the target force and adjusts the electric motor operation accordingly, achieving precise force control through feedback without overly complex mechanisms.
Solution Approach 2:
The self-locking worm gear automatically maintains the set clamping force without requiring complex active control systems. The mechanical self-locking property provides passive force maintenance, reducing the complexity of the control system while still achieving precise braking force control.
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 system provides a simple and reliable mechanism to maintain a consistent braking force, adapting to dimensional changes in brake components and ensuring the vehicle remains stationary despite temperature variations, with minimal energy consumption and no need for additional locking mechanisms.
Implementation Method 1
The gear assembly (220) contains a worm gear arrangement (300) with a gearing ratio configured to de facto prevent a position of the at least one pressing member (211, 212) to be altered by movement of the at least one pressing member (211, 212)
Implementation Method 2
The gear assembly (220) contains a worm gear arrangement (300) with a gearing ratio configured to de facto prevent a position of the at least one pressing member (211, 212) to be altered by movement of the at least one pressing member (211, 212)
Data Source
Figure 1~2
Figure 3~6
Figure 4a~7
AI summary
A rail vehicle brake system includes a brake unit (200) that receives an electric brake-force signal (BF) designating a set force value (Fset). The brake unit (200) contains: pressing members (211, 212), a rotatable member mechanically linked a wheel of the rail vehicle, a gear assembly (220) that operates mechanically on the pressing members (211; 212) so as to move them towards or away from the rotatable member, an electric motor (230) that, in response to the electric brake-force signal (BF), acts on the gear assembly (220) to cause the gear assembly (220) to operate the pressing members (211; 212), a load-cell sensor (250) produces a sensor signal (F) representing the force applied by the pressing members (211, 212), and a locking mechanism that locks the pressing members (211; 212). The brake actuator (120) obtains the sensor signal (F). When the magnitude of the applied force matches the set force value (Fset), the brake actuator (120) controls the locking mechanism to lock the pressing members (211; 212). The locking mechanism is self-locking, included in and forms an integral part of the gear assembly (220).