Motor Assembly Bearing Sheet Radial Constraint
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Solution Overview
Problem
The conventional motor assembly for windshield wipers requires separate cutting processes to form the receiving portion and the hole for the rotary shaft, leading to increased manufacturing costs and performance degradation due to machining and assembling errors, which result in inconsistent distance between the rotary shaft and the output shaft.
Innovation Solution
A motor assembly with a supporting body featuring an open receiving portion for the bearing member, where a bearing sheet is forcibly inserted to prevent radial movement, using a die-casting method for the bearing sheet to ensure accurate and cost-effective fabrication, and a coaxial insertion of the output shaft into the inner race of the bearing member.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If separate cutting processes are used to form the receiving portion and the hole for the rotary shaft, then the manufacturing process can accommodate perpendicular axes, but the manufacturing cost increases and machining errors cause inconsistent distances between components
Solution Approach 1:
The receiving portion and the hole for the rotary shaft are formed as integrated features in the supporting body through die-casting, combining what were previously separate machining operations into a single molding process. This eliminates the need for separate cutting processes and ensures precise positional relationships between features.
Solution Approach 2:
Traditional mechanical cutting processes are replaced with die-casting molding to form the receiving portion and mounting hole. This substitution of manufacturing methodology enables complex three-dimensional features with precise geometric relationships to be created in a single process step.
2Ease of manufacture
If separate cutting processes are used to form the receiving portion and the hole for the rotary shaft, then the perpendicular axes can be accommodated, but the manufacturing cost increases
Solution Approach 1:
Multiple cutting operations are merged into a single die-casting process that forms both the receiving portion and the rotary shaft mounting hole with correct perpendicular orientation in one manufacturing step, reducing process complexity.
Solution Approach 2:
The geometric relationships between the receiving portion and mounting hole are predetermined and built into the die-casting mold itself, so that the correct perpendicular orientation and positioning are established during molding rather than requiring subsequent machining operations.
3Stability of the object's composition
If the bearing member is supported by a closed cylindrical receiving portion, then the bearing member is prevented from radial movement, but the manufacturing cost increases due to additional cutting processes
Solution Approach 1:
The receiving portion is designed as an open structure with a bottom wall and lateral walls that define a receiving space, rather than a fully enclosed cylinder. The bearing sheet provides additional support, segmenting the support function between the receiving portion structure and the bearing sheet material.
Solution Approach 2:
A bearing sheet is used to provide radial support to the bearing member, replacing the need for a fully rigid closed cylindrical structure. The bearing sheet acts as a flexible thin film that provides the necessary radial constraint while allowing for simpler manufacturing.
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 reduces manufacturing costs, prevents radial movement of the bearing member, and improves the motor assembly's performance by maintaining consistent distances between components, thereby enhancing the motor's stability and reducing noise and vibration.
Implementation Method 1
The bearing sheet 100 supports elastically the bearing member 7 toward the output shaft 4 of the motor 3
Data Source
AI summary
Provided is a motor assembly including a supporting body; a bearing member including an inner race and an outer race; and a supporting unit for supporting the bearing member onto the supporting body, wherein the supporting body comprises: a receiving portion with an opening on a portion in the diameter direction of the output shaft for receiving the bearing member having a first supporting surface disposed perpendicularly to the output shaft of the motor and a second supporting surface separated from the first supporting surface in parallel to the first supporting surface; a side surface of the outer race of the bearing member contacts the first supporting surface, the supporting unit includes a bearing sheet that is forcedly inserted between the other side surface of the outer race in the bearing member that is received in the receiving portion and the second supporting surface, wherein the bearing sheet includes a radial supporting portion contacting an outer circumferential surface of the bearing member received in the receiving portion so as to prevent the bearing member from escaping from the receiving portion.