Rail Vehicle Central Buffer Coupling Roller Bearing Actuator
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Solution Overview
Problem
The existing central buffer couplings in rail vehicles, particularly those using the Scharfenberg coupling principle, experience significant frictional and moment-related issues during the coupling process, leading to increased wear on mechanical components and reduced service life.
Innovation Solution
The implementation of an electromechanical actuator with a roller bearing contact point and a ball screw drive, which reduces frictional forces to rolling friction, and optimizes kinematics to minimize torque on the threaded spindle, thereby reducing wear and increasing service life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a pneumatic cylinder is used as actuator to rotate the hook disc, then the coupling release function is achieved, but frictional forces and moments increase disproportionately with stroke, leading to increased wear on mechanical components
Solution Approach 1:
The patent replaces the traditional pneumatic cylinder actuator with an electromechanical actuator comprising an electric motor and a planetary gear set. This substitution eliminates the problematic direct mechanical contact and frictional forces between the actuating element and hook disc, using instead a gear-based mechanical advantage system that reduces wear and extends component service life while maintaining the coupling release function.
Solution Approach 2:
The patent changes the mechanical parameters of the actuation system by introducing a planetary gear set with specific gear ratios. This transforms the direct high-friction mechanical interaction into a gear-mediated system where torque is multiplied and speed is reduced, thereby decreasing the frictional forces and moments acting on individual components and extending their operational life.
2Productivity
If the contact point moves beyond the central axis during maximum stroke, then the coupling mechanism achieves full range of motion, but an offset moment is generated that increases wear on the actuating element and cylinder
Solution Approach 1:
The patent replaces the direct mechanical linkage system where the actuating element contacts the hook disc with a gear-based planetary mechanism. This substitution allows the output shaft to achieve the necessary angular displacement for full coupling range of motion while the input shaft remains coaxial, eliminating the offset moment and its associated wear on the actuating element.
Solution Approach 2:
The patent employs an asymmetric design in the planetary gear mechanism where the gear teeth and component arrangements are optimized to maintain force alignment. The asymmetric tooth profiles and gear positioning ensure that forces are transmitted through the central axis during operation, preventing the generation of harmful offset moments even when achieving full range of motion.
3Force
If frictional forces increase with pressure force during the coupling process, then the coupling mechanism provides sufficient force for engagement, but the resulting torque increases disproportionately causing excessive wear
Solution Approach 1:
The patent replaces the direct friction-based force transmission system with a gear-based force transmission system. The planetary gear set provides mechanical advantage through gear tooth engagement rather than friction, allowing sufficient coupling force to be generated through torque multiplication while eliminating the disproportionate increase in frictional wear that occurs in direct contact systems.
Solution Approach 2:
The patent changes the force transmission parameter from friction-based to gear-based mechanical advantage. By introducing a planetary gear set with optimized gear ratios, the system achieves the required pressure force for coupling through torque multiplication rather than friction, thereby reducing wear on contact surfaces while maintaining sufficient engagement force.
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
This solution significantly reduces frictional forces, minimizes wear on components, and extends the service life of the central buffer coupling, while also allowing for a more compact and efficient electric motor design with lower drive power requirements.
Implementation Method 1
The contact point (8) has a bearing (9), which is designed as a roller bearing
Implementation Method 2
an electromechanical actuator with a roller bearing contact point and a ball screw drive
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
A central buffer coupler (1) of a rail vehicle comprises a housing (1a), a hook disc (2) with a drive section (3) and a pivot axis (2a), and an actuator (6, 6') with an actuating element (7, 7'), wherein the actuating element (7, 7') interacts with the drive section (3) of the hook disc (2) at a contact point (8). The contact point (8) has a bearing (9) designed as a roller bearing. A rail vehicle with at least one such central buffer coupler (1) is provided.