Vehicle Geared Motor Shaft Layout for Reduced Width
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Solution Overview
Problem
Existing geared motors for vehicles, particularly straddle type vehicles like motorcycles, face challenges in compactness due to the increased distance between the motor case and power transmission members, which affects vehicle width and stability.
Innovation Solution
The design includes a gear shaft protruding from the motor case with an inner bearing at the axial inner side, a driven gear at the axial outer side, a rotating member coupled to the power transmission member, and an outer bearing at the axial outer side, optimizing the placement to reduce the axial dimension and enhance load-bearing capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If two bearings for the motor and the gear and a reduction gear are disposed between the power transmission member and a motor case, then the motor can transmit power to the rear wheel, but the distance between an outer end surface of the motor case and the power transmission member increases
Solution Approach 1:
The patent applies nesting by placing the driven gear inside the space between the two bearings along the axial direction. Specifically, the first bearing is disposed between the motor case and the driven gear, the second bearing is disposed between the driven gear and the power transmission member, creating a nested arrangement where the gear is positioned within the bearing spacing. This reduces the overall axial distance compared to placing bearings and gear in sequence without nesting.
Solution Approach 2:
The patent optimizes the axial arrangement of components along the axial direction of the gear shaft. By carefully positioning the driven gear at a specific axial location between the two bearings, and by specifying that the gear shaft protrudes from the motor case in the axial direction, the design achieves compactness in the axial dimension while maintaining proper power transmission function.
2Adaptability or versatility
If the gear shaft and motor shaft extend in vehicle width direction with gear shaft closer to pivot shaft, then the motor can be integrated with reduction gear, but the vehicle width size may increase
Solution Approach 1:
The patent segments the motor assembly into distinct functional components: the motor case containing the motor, the gear shaft assembly with bearings and driven gear, and the power transmission member coupling. This segmentation allows each component to be optimized independently and assembled in a compact configuration where the gear shaft extends axially from the motor case, reducing overall width while maintaining integration.
Solution Approach 2:
The patent employs asymmetric positioning where the gear shaft is disposed closer to the pivot shaft than the motor shaft, and the gear shaft protrudes from the motor case in the axial direction rather than being symmetrically arranged. This asymmetric configuration optimizes the use of available space and achieves compact vehicle width dimensions while maintaining proper mechanical function.
Data Source
AI summary
A motor is to be mounted on a vehicle as a drive source. The motor includes a motor shaft extending in an axial direction, a drive gear provided on the motor shaft, a gear shaft extending in the axial direction, a driven gear provided on the gear shaft and coupled to the drive gear, a rotating member, an inner bearing that supports the gear shaft, and an outer bearing that supports the gear shaft. The rotating member is provided on the gear shaft and is configured to be coupled to a power transmission member that transmits power to a wheel of the vehicle. The rotating member is located between the inner bearing and the outer bearing in the axial direction.