Integrated Rotary Encoder in Motor End Shield for Magnetic Shielding
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing electric drive units with rotary encoders require a separate housing, leading to increased complexity and space requirements due to the need for additional space to accommodate the encoder, resulting in a less cost-effective and more cumbersome design.
Innovation Solution
Integrating the sensor for detecting a magnetic field into the bearing shield of the electric motor, with the transmitter element arranged parallel to the axis and a shielding element to minimize additional shaft space and shield against external magnetic influences, allowing the encoder element to be placed within the end shield without additional space requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate housing is used for the rotary encoder, then the sensor can be properly positioned and shielded, but the device complexity and space requirements increase
Solution Approach 1:
The patent combines the bearing shield and encoder housing into a single integrated component. The bearing shield serves dual functions: supporting the bearing and housing the encoder sensor, while the encoder element is mounted on the shaft within the same structural envelope. This eliminates the need for a separate encoder housing while maintaining sensor shielding effectiveness through the conductive material in the bearing shield.
Solution Approach 2:
The bearing shield is designed to perform multiple functions simultaneously: it supports the bearing, houses the encoder sensor, provides magnetic shielding through conductive material, and serves as the structural housing for the encoder assembly. This multi-functionality reduces the overall number of components and simplifies the drive system structure.
2Reliability
If a separate housing is used for the rotary encoder, then the sensor can be enclosed, but the space requirements and footprint increase
Solution Approach 1:
The encoder sensor is housed within the existing bearing shield structure rather than requiring a separate encoder housing. The encoder element is mounted on the shaft in close proximity to the sensor, utilizing the same structural space. This integration eliminates the need for additional axial space on the shaft and reduces the overall footprint of the drive system.
Solution Approach 2:
The encoder element is positioned in a radial direction from the shaft, parallel to the axis, rather than extending axially along the shaft. This spatial arrangement allows the encoder to be accommodated within the radial clearance of the bearing shield without increasing the axial length of the motor shaft, thereby reducing the overall footprint.
3Area of stationary object
If the sensor is integrated into the bearing shield, then space requirements are reduced, but shielding against external magnetic fields becomes more challenging
Solution Approach 1:
The bearing shield is made from conductive material, changing its electromagnetic properties to provide magnetic shielding. This material property modification allows the shield to block external magnetic fields from reaching the encoder sensor, while the integrated design maintains compact space requirements.
Solution Approach 2:
The bearing shield utilizes conductive material that combines mechanical support functions with electromagnetic shielding properties. This composite approach integrates structural and protective functions in a single material selection, enabling space-efficient design while maintaining shielding effectiveness against magnetic interference.
4Length of moving object
If the encoder element is positioned radially, then additional shaft space is minimized, but the magnetic field detection becomes more complex
Solution Approach 1:
The encoder element is positioned radially from the shaft axis rather than axially along the shaft, utilizing the radial clearance space within the bearing shield. This spatial reconfiguration minimizes the axial length requirements while the magnetic field detection remains effective because the sensor is positioned in close proximity to the encoder element in the radial direction, maintaining strong magnetic coupling.
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 results in a more compact and cost-effective electric drive unit with reduced space requirements and improved shielding against external magnetic interference, enabling efficient operation without separate components for shielding and friction.
Implementation Method 1
A common principle by which such rotary encoders can detect the movement of the motor shaft is based on the detection of magnetic fields by a sensor suitable for detecting magnetic fields. This sensor detects a magnetic field generated by a encoder element.
Implementation Method 2
The electric motor has a shielding element for magnetically shielding the sensor from an external magnetic field acting on the motor. This shielding element can be, for example, a shielding plate.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The invention relates to an electric motor, wherein the electric motor has an end shield (5), wherein the electric motor has a sensor (7) for detecting a magnetic field. The sensor (7) is integrated into the end shield (5) of the electric motor. The invention also relates to an electric drive unit (1) comprising a brake (3), in particular an electromagnetically actuatable brake (3), and an electric motor, wherein a shielding element (8) is arranged between the sensor (7) and the brake (3).