Annular Cover Protects Oil Seal in Drive Device
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Solution Overview
Problem
The existing drive devices with wet brakes are prone to damage from debris, such as strings, that can get caught and carried to the oil seal, potentially damaging it.
Innovation Solution
A drive device configuration that includes an annular cover to secure the fasteners and prevent debris from reaching the oil seal, with the cover being positioned between the hub and housing to protect the oil seal from external interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the hub is exposed without a cover, then the fasteners are accessible for maintenance and inspection, but debris can be caught by the rotating hub and carried to the oil seal causing damage
Solution Approach 1:
The hub assembly is segmented into functional zones: the inner hub portion with fasteners remains accessible, while the outer hub portion is protected by a cover. This segmentation allows different parts to serve different purposes - maintenance accessibility versus debris protection - resolving the contradiction between ease of operation and reliability
Solution Approach 2:
A cover is introduced as an intermediary element between the external environment (source of debris) and the oil seal (protected component). The cover acts as a mediator that blocks debris from reaching the oil seal while allowing the fasteners to remain accessible for maintenance, thus protecting the oil seal without compromising accessibility
2Reliability
If a cover is added to protect the oil seal, then debris is prevented from reaching the oil seal, but the device complexity increases
Solution Approach 1:
A thin cover component is used to protect the oil seal from debris. This thin-film approach provides effective protection while adding minimal structural complexity and mass to the device, resolving the contradiction between reliability improvement and device complexity
Solution Approach 2:
The protective function is extracted as a separate cover component rather than being integrated into the main hub structure. This extraction allows the cover to be easily installed and removed for maintenance while keeping the rest of the device simple, thus protecting the oil seal without significantly increasing overall device complexity
Data Source
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AI summary
A drive device (1) for driving and rotating a wheel (2) includes an axle shaft (4), a hub (6) to which rotation of the axle shaft (4) is conveyed, a plurality of fasteners (18) for securing the wheel (2) to the hub (6), a wet brake (7), a housing (9, 10), an oil seal (29), and a cover (30). The wet brake (7) is configured to restrain the rotation of the axle shaft (4). The housing (9) accommodates the axle shaft (4) and the wet brake (7). The oil seal (29) is disposed between the housing (10) and a part (14) of the hub (6) that is disposed inward of the fasteners (18) in a radial direction of the hub (6). The cover (30) has an annular shape. The cover (30) is disposed in a space (S) formed between the hub (6) and the housing (10), and is secured to the housing (10). The cover (30) is configured to cover the plurality of fasteners (18).