Bearing Shield Press-Fit Structure for Actuator Shaft Alignment
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Solution Overview
Problem
Conventional drive devices for electric machines face misalignment issues due to radial press forces during assembly, which can lead to improper orientation of the bearing shield and subsequent misalignment of the roller bearing.
Innovation Solution
The bearing shield's retaining segment is designed with a first axial partial segment and a second partial segment of larger outer diameter, ensuring that radial press forces act away from the annular disk-shaped floor segment, preventing misalignment and allowing for a secure seating within the housing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the bearing shield is pressed into the housing or the housing is shrunk onto the bearing shield, then the bearing shield is securely fixed in the housing, but the orientation of the bearing shield and floor segment may be impaired, leading to misalignment of the roller bearing
Solution Approach 1:
The retaining segment is divided into two partial segments with different diameters. The first partial segment has a smaller diameter that allows it to pass through the housing without contact, while the second partial segment has a larger diameter that provides the pressing surface. This segmentation allows the fixation force to be applied at a distance from the floor segment, preventing orientation impairment during assembly.
2Ease of manufacture
If the retaining segment has a uniform diameter, then the manufacturing of the bearing shield is simplified, but the pressing forces may directly affect the floor segment and cause misalignment
Solution Approach 1:
The retaining segment has different diameters in different axial regions. The first partial segment has a smaller diameter suitable for passing through the housing, while the second partial segment has a larger diameter for providing a stable pressing surface. This local variation in geometry allows the pressing forces to be applied away from the floor segment, preventing misalignment while maintaining manufacturing feasibility through deep-drawing processes.
3Productivity
If the bearing shield is pressed into the housing, then assembly is simplified, but radial press forces may cause the floor segment to pivot out of the perpendicular plane
Solution Approach 1:
The second partial segment of the retaining segment acts as an intermediary element between the housing and the floor segment. By providing a larger diameter pressing surface at a distance from the floor segment, it mediates the transmission of pressing forces, preventing them from directly affecting the floor segment's orientation while still enabling secure fixation and simplified assembly.
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 ensures precise orientation of the bearing shield and roller bearing, preventing misalignment and simplifying the assembly process while maintaining a constant inner diameter for the housing, thus enhancing manufacturing efficiency and sealing capabilities.
Implementation Method 1
a bearing shield (9) that is held with a frictional fit in the housing (4)
Data Source
AI summary
A drive device for an actuator for a brake device of a motor vehicle. The drive device has an electric machine having a rotor rotatably mounted in a housing and a stator fixed to the housing. A bearing shield is situated in the housing that has an axially extending sleeve-shaped bearing segment for the rotatable bearing of a drive shaft, which bears the rotor. The bearing shield has an axially extending sleeve-shaped retaining segment held with a frictional fit in a sleeve-shaped end segment of the housing and has a diameter that is greater than the diameter of the bearing segment. A radially extending annular disk-shaped floor segment of the bearing shield is between the retaining segment and the bearing segment. The retaining segment has a first axial partial segment connected to the floor segment, and a second partial segment connected to the first partial segment.