Direct-Drive Rail Bogie With Liquid-Cooled Motor Fairing
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Solution Overview
Problem
High-speed rail vehicles face challenges in heat dissipation of traction motors, particularly when the bogie is covered, leading to inefficient energy consumption due to poor aerodynamics and increased air resistance.
Innovation Solution
A bogie design with a permanently excited synchronous motor as a direct drive, featuring liquid cooling and a fully enclosed shell-shaped cladding, allowing for efficient heat dissipation through a closed internal cooling circuit and water jacket cooling, eliminating the need for external airflow and gearbox heat loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a full aerodynamic covering is provided for the bogie, then aerodynamic efficiency is improved, but heat dissipation of the traction motor deteriorates
Solution Approach 1:
The cooling system is segmented into multiple independent pathways: a first cooling pathway for the traction motor using a water jacket, and a second cooling pathway for power electronics modules. This segmentation allows each component to be cooled independently without interfering with the aerodynamic covering.
Solution Approach 2:
A water jacket is introduced as an intermediary cooling medium between the traction motor and the external environment. The water jacket absorbs heat from the traction motor and transports it to a cooling plate, enabling heat dissipation without requiring direct airflow to the motor, thus maintaining aerodynamic efficiency.
2Temperature
If self-ventilated or forced-ventilated traction motors are used, then cooling is achieved, but air resistance increases due to required airflow paths
Solution Approach 1:
The invention transitions from pneumatic cooling (air-based ventilation) to hydraulic cooling (water-based jacket system). The water jacket circulates coolant to absorb and remove heat from the traction motor, eliminating the need for air intake and exhaust paths, thereby reducing air resistance and improving aerodynamic efficiency.
3Speed
If a gearbox is used for drive transmission, then speed control is improved, but device complexity and heat generation increase
Solution Approach 1:
The gearbox is completely removed from the drive system. The traction motor is directly coupled to the wheelset, eliminating the intermediate transmission mechanism. This extraction simplifies the device structure, reduces the number of moving parts, and eliminates the heat generation associated with gear friction and mechanical losses.
Solution Approach 2:
The functions of the gearbox and traction motor are merged into a direct-drive configuration. The traction motor's rotor is directly connected to the wheelset axle, combining the motor and drive transmission into a single integrated system, thereby reducing complexity while maintaining speed control capability through electrical means.
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 design reduces energy consumption by minimizing air resistance, effectively cooling the traction motor within the bogie, and maintaining efficient motor performance while ensuring aerodynamic efficiency and reduced energy usage.
Implementation Method 1
the liquid cooling being designed as a liquid cooling jacket
Implementation Method 2
a closed internal cooling circuit that can be recooled on the liquid jacket
Implementation Method 3
a permanently excited synchronous motor
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The invention relates to a bogie (21) of a rail vehicle, having: - at least one wheelset (24) with two oppositely situated wheels (11) which are rigidly connected to one another, - a wheelset bearing arrangement (13) of the wheelset (24) within the two wheels (11), - a traction motor (1) which directly drives the wheelset (24), wherein the traction motor (1) is a permanently excited synchronous motor with liquid cooling (7), - an aerodynamic panelling (20) of the bogie (21).