Motor Bearing Support Structure for Shaft-Gear Center Alignment
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Solution Overview
Problem
The alignment or misalignment between the rotation center of the rotation shaft and the planetary gear reducer in existing motor devices is dependent on the molding accuracy of the housing protrusion, leading to inconsistent transmission of driving force and varying motor characteristics.
Innovation Solution
A motor device design where the motor case and gear case are arranged in the axial direction of the rotation shaft, with bearings supporting the rotation shaft and sun gear, and using opposing members to align the ring magnet and rotor core axes, ensuring precise alignment and stable rotation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the rotation shaft is supported by a bearing fixed to a protrusion of the housing, then the structure is compact and easy to manufacture, but the alignment between the rotation center of the rotation shaft and the rotation center of the planetary gear reducer shifts when molding accuracy is low, causing inconsistent driving force transmission
Solution Approach 1:
A dedicated bearing support structure is introduced as an intermediary component between the housing and the bearing. This support structure provides precise positioning features that ensure accurate alignment of the rotation shaft with the planetary gear reducer, decoupling the alignment precision from the housing molding accuracy and enabling consistent driving force transmission while maintaining ease of manufacture.
2Device complexity
If the rotation shaft and planetary gear reducer are aligned using housing protrusion molding, then the device complexity is reduced, but the reliability of driving force transmission varies from product to product due to molding accuracy variations
Solution Approach 1:
The housing structure is segmented into functional zones: a general housing body for structural support and a dedicated bearing support structure for precise alignment. This segmentation allows the bearing support to provide consistent, high-precision positioning independent of variations in overall housing molding accuracy, thereby improving reliability while keeping the overall device complexity manageable through modular design.
Data Source
AI summary
A motor device includes: a first ball bearing rotatably supporting a rotation shaft, and a first sun gear mounted to an end part of the rotation shaft and disposed at the center of a first planetary gear reducer. A motor case is provided with a bearing support tube disposed coaxially with respect to the rotation shaft, and a gear case is provided with a through hole of a blocking member disposed coaxially with respect to the first sun gear. Both axial sides of the first ball bearing are respectively mounted to the bearing support tube and the through hole. Thus, the rotation centers of the rotation shaft and the first planetary gear reducer can be precisely aligned with each other based on the first ball bearing regardless of the molding accuracy of the motor case.