Stepped Shaft Design for Reducing Friction in Image Forming Apparatuses
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Solution Overview
Problem
Conventional driving force transmission mechanisms experience significant losses due to friction and thrust loads, with existing solutions failing to effectively minimize these losses, particularly in image forming apparatuses where electric power consumption is a concern.
Innovation Solution
A driving force transmission mechanism featuring a shaft with a large diameter portion, a small diameter portion, and a middle diameter portion, along with stepped sections to optimize the bearing of radial and thrust loads, reducing the contact area and friction between the gear and shaft, and utilizing lubricant only in defined areas to minimize shearing losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single diameter shaft is used, then the structure is simple, but it cannot effectively reduce driving force transmission loss from thrust load
Solution Approach 1:
The shaft incorporates local quality variations through different diameter portions, where each portion is specifically designed to handle different load types. The small diameter portion is strategically positioned to contact the thrust load bearing surface, creating a localized optimization that reduces thrust load transmission loss without requiring complete structural redesign.
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 significantly reduces torque loss and frictional wear, minimizing the overall driving force transmission loss attributed to both radial and thrust loads, while optimizing lubricant usage and preventing excessive lubricant consumption, thus enhancing the efficiency and power conservation in image forming apparatuses.
Implementation Method 1
Some of the causes of the driving force transmission loss, which occurs to driving force transmission mechanisms such as the one shown in FIG. 8, is the loss attributable to the friction, which occurs to the driving force transmitting section 121a of the gear 121, and the friction which occurs between the shaft 121 and gear 121.
Implementation Method 2
it has been widely known to apply lubricant between the peripheral surface of the shaft 122 and the shaft contacting portion 121b of the gear 121
Implementation Method 3
the area of contact between the gear 121 and shaft 122, and between the gear 121 and the other components other than the shaft 122, are coated with lubricant to reduce the driving force transmission loss attributable to the force necessary to shear the lubricant in the above described area of contact
Data Source
AI summary
A drive transmission mechanism includes a rotatable member provided with a drive transmitting portion; and a shaft supporting the rotatable member; wherein the shaft has a large diameter portion, a small diameter portion having a diameter smaller than that of the large diameter portion, at least one middle diameter portion having a diameter smaller than that of the large diameter portion and larger than that of the small diameter portion, and a stepped portion at a boundary between the small diameter portion and the middle diameter portion.