Rail Motor Speed Sensor Layout Using Coupling-Mounted Sensor Wheel
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Solution Overview
Problem
Existing electric motors for rail vehicles face challenges in arranging components for controlling the motor in a space-saving manner, particularly in limited spaces like bogies, and require efficient speed sensing without additional installation space or protection from heat and debris.
Innovation Solution
The electric motor integrates a speed sensor mounted on a bearing plate, with a sensor wheel on a coupling, allowing for space-saving arrangement and protection from heat and debris, using a curved-tooth coupling to connect the rotor and wheelset shaft, and employing multiple speed sensors on threaded blind holes in the bearing plate for various control functions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the speed sensor is mounted inside the motor housing, then it is easier to install and protect, but it is exposed to high temperatures that can affect its reliability
Solution Approach 1:
The speed sensor is extracted from the motor housing interior and mounted on the exterior bearing plate. This separation removes the sensor from the high-temperature environment inside the motor while maintaining its functional connection to the rotor through the external sensor wheel, thereby protecting it from thermal damage.
Solution Approach 2:
The sensor wheel mounted on the coupling acts as an intermediary between the rotor and the speed sensor. It transfers rotational information from the high-temperature rotor area to the cooler external sensor without requiring the sensor itself to be in the hot environment.
2Measurement precision
If additional components are added for speed sensing, then control precision is improved, but the device complexity and space requirements increase
Solution Approach 1:
The sensor wheel is integrated into the coupling structure, merging two separate components into one. This eliminates the need for additional mounting space and reduces overall device complexity while maintaining the speed sensing function.
Solution Approach 2:
The coupling serves multiple functions: it connects the rotor to the output shaft, compensates for misalignment, and provides a mounting surface for the sensor wheel. This multi-functionality reduces the need for separate components and simplifies the overall device structure.
3Ease of manufacture
If the sensor wheel is mounted separately from the coupling, then it is easier to install, but additional axial space is required which is limited in bogie installations
Solution Approach 1:
The sensor wheel is merged with the coupling structure, eliminating the need for separate mounting brackets or additional axial space. The sensor wheel becomes an integral part of the coupling assembly, maintaining ease of installation while minimizing space requirements.
4Object-affected harmful factors
If the speed sensor is mounted on the bearing plate, then it is protected from stone chips and debris, but the mounting structure becomes more complex
Solution Approach 1:
The bearing plate serves its primary function of supporting the motor bearings while also providing a mounting surface for the speed sensor. This dual functionality eliminates the need for separate protective housings or mounting structures, reducing overall complexity while providing protection from debris.
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 configuration achieves a space-saving, reliable, and cost-effective solution that protects the speed sensor from heat and debris, enabling precise speed and rotation control for high-performance motors in rail vehicles.
Implementation Method 1
the speed sensor is configured to scan the teeth of a sensor wheel connected to the rotor
Implementation Method 2
The coupling can compensate for relative movement between the motor shaft and the wheelset shaft or transmission shaft
Data Source
Figure 1~2
Figure 3~4
AI summary
The invention relates to an electric motor (1) for a rail vehicle, having a rotational speed sensor (3). According to the invention, the rotational speed sensor (3) is mounted to an end shield (2) of the electric motor (1), and a sensor wheel (5) for the rotational speed sensor (3) is mounted to a clutch (4) of the electric motor (2).