Stator Winding Sensor Mount With Expandable Thermal Contact
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Solution Overview
Problem
Existing temperature sensors in electric machines, particularly in electric vehicles, struggle to accurately measure the maximum temperature of tightly wound windings due to their inaccessible location, leading to inaccurate readings and maintenance challenges.
Innovation Solution
A sensor mounting system with a pivotable connection, expandable design, and spreading element allows the temperature sensor to be inserted axially past the winding, pressing it against the radially inner edge for accurate temperature measurement, utilizing an insulating plastic material for thermal contact and a self-locking mechanism for secure positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a temperature sensor is installed inside the stator winding to measure the maximum temperature, then the measurement precision is improved, but the ease of operation for maintenance deteriorates because the sensor becomes inaccessible from the outside
Solution Approach 1:
The temperature sensor is nested within the sensor mounting structure, which itself is designed to be inserted into the stator winding space. The mounting structure acts as a carrier that protects the sensor while allowing it to reach the measurement position deep within the winding, making the sensor indirectly accessible through the radial insertion path.
Solution Approach 2:
The sensor mounting structure is pre-assembled with the temperature sensor before insertion into the stator. The mounting structure is designed in advance with the capability to be inserted radially and then expanded to secure the sensor in the optimal measurement position, eliminating the need for complex in-situ assembly during maintenance.
2Ease of operation
If the sensor mounting structure is made compact to facilitate insertion past the winding, then the ease of operation is improved, but the reliability of thermal contact deteriorates
Solution Approach 1:
The sensor mounting structure transitions from a compact, low-profile state during insertion to an expanded, stable state during operation. The mounting structure can be radially expanded after insertion to increase the contact force between the temperature sensor and the winding, ensuring reliable thermal contact while maintaining ease of insertion in the compact state.
Solution Approach 2:
The mounting structure changes its physical parameters (radial dimension, contact force) after insertion. By expanding radially or applying spring force, the structure increases the pressure between the sensor and winding surface, improving thermal contact reliability without affecting the initial compact insertion capability.
3Reliability
If the spreading element is inserted to expand the holding body away from the support body for secure sensor positioning, then the reliability of sensor positioning is improved, but the device complexity increases
Solution Approach 1:
The spreading element is designed to be inserted through the central web opening and automatically expands the holding body away from the support body using its own structural properties (such as spring force or elastic deformation). The structure self-adjusts to secure the temperature sensor in the correct position without requiring additional actuators or complex control mechanisms.
4Measurement precision
If the temperature sensor is pressed against the radially inner edge of the winding to measure maximum temperature, then the measurement precision is improved, but the stress on the sensor and mounting structure increases
Solution Approach 1:
The mounting structure uses elastic or flexible materials that can deform under the pressing force required to achieve good thermal contact. The material parameters (elasticity, flexibility) are selected to allow sufficient contact force for accurate measurement while remaining within the elastic limit to prevent permanent deformation or failure of the sensor and mounting structure.
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
Enables maintenance-friendly and accurate measurement of maximum winding temperatures by ensuring thermal contact at the radially inner edge, minimizing deformation and damage, and facilitating easy sensor replacement.
Implementation Method 1
the spreading element can thus press the holding body, together with the temperature sensor, away from the stator lamination and onto the winding
Implementation Method 2
the material can be elastically bent slightly by the force applied by the expanding agent in the axial direction of the electrical machine, thus ensuring thermal contact between the temperature sensor and the radially inner edge of the winding
Implementation Method 3
Between the axial edge of the winding, to which the temperature sensor is pressed, and an axially central inner wire section of the winding, heat transfer occurs primarily through conduction
Data Source
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AI summary
The invention relates to a sensor fastening device (10) for temperature measurement in an electrical machine for driving a motor vehicle, comprising a retaining body (16) for receiving a temperature sensor (12), a support body (20) for resting against a stator lamination (22) of the electrical machine, the support body (20) being connected to the retaining body (16) spreadably, in particular substantially jointedly, and a spreading element (36) for spreading the retaining body (16) away from the support body (20). By means of the sensor fastening device (10), which can be shifted in the radial direction and can be moved past the winding (14) axially, the temperature sensor (12) can be positioned, from the radial outside, on the radially inner edge of the winding (14) and can be thermally coupled by means of the spreading element (36) such that maintenance-friendly and accurate measurement of a maximum temperature in a winding (14) of an electrical machine for a motor vehicle is made possible.