Motor Rotor Conductive Pillar Grounding for Shaft Current Discharge
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Solution Overview
Problem
Conductive bearings in conventional motor rotors experience unstable grounding during high-speed operation, leading to electrical corrosion of both the conductive bearing and the main bearing due to inadequate contact, resulting in reduced service life and potential damage from offset loading forces.
Innovation Solution
A motor rotor design featuring a conductive pillar that passes through the conductive bearing, with an outer wall interference fit to ensure stable contact and even force distribution, preventing electrical corrosion by maintaining continuous electrical connection and reducing stress concentrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conductive spring is pressed against the inner ring of the conductive bearing, then the shaft current can be discharged, but the conductive bearing cannot be stably grounded during high-speed operation due to axial and radial movement
Solution Approach 1:
The patent introduces a conductive pillar as an intermediary component between the conductive bearing and the grounding system. The conductive pillar passes through the conductive bearing and provides a stable grounding path, mediating the connection between the moving conductive bearing and the stationary grounding system, thereby ensuring stable discharge of shaft current during high-speed operation
Solution Approach 2:
The patent accommodates the dynamic movement of the conductive bearing during high-speed operation by allowing the conductive pillar to move axially and radially within the shaft hole while maintaining continuous electrical contact. This dynamic design ensures that the grounding connection remains stable despite the bearing's movement
2Reliability
If a conductive spring is used to ground the conductive bearing, then shaft current can be discharged, but offset loading forces cause concentrated stress and damage to the conductive bearing
Solution Approach 1:
The conductive pillar serves as a mediator that distributes the grounding function across its entire surface area rather than concentrating force at a single point. The pillar's cylindrical surface provides uniform contact with the inner ring of the conductive bearing, distributing loading forces evenly and preventing concentrated stress
Solution Approach 2:
The patent achieves homogeneous force distribution by using the conductive pillar's cylindrical surface to contact the inner ring of the conductive bearing uniformly around the circumference. This homogeneous contact ensures even distribution of electrical and mechanical loads, preventing localized stress concentrations that could damage the bearing
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
The design ensures stable discharge of shaft current, prevents conductive bearing damage, and prolongs service life by maintaining continuous electrical connection and evenly distributing forces, thereby preventing electrical corrosion and wear.
Implementation Method 1
a shaft current is generated on a motor rotor. When the shaft current is discharged to a main bearing sleeved on an outer periphery of the motor rotor, the main bearing is electrically corroded
Implementation Method 2
an outer ring of the conductive bearing interference fits with an inner wall of the shaft hole
Implementation Method 3
an inner ring of the conductive bearing interference fits with an outer wall of the conductive pillar
Data Source
AI summary
Embodiments of this application provide a motor rotor, a motor, and a vehicle. A conductive pillar passes through an inner ring of a conductive bearing, an outer wall of the conductive pillar interference fits with the inner ring of the conductive bearing, and an end of the conductive pillar is grounded. In this way, it is ensured that a shaft current on a rotor body is discharged by using the conductive bearing and the conductive pillar, to prevent a main bearing of the motor rotor from being electrically corroded by the shaft current. In addition, the conductive bearing is sleeved on the grounded conductive pillar, so that the inner ring of the conductive bearing can interference fit with the outer wall of the conductive pillar.