Clutch Output Shaft Shim Structure to Block Bearing Grease Scatter

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Solution Overview

Problem

Conventional driving force transmission devices in image forming apparatuses fail to effectively prevent grease scattering from bearings, leading to operational failures in electromagnetic clutches due to grease adherence, and existing solutions are costly and inefficient.

Innovation Solution

A driving force transmission device incorporating an annular shim with a through hole matching the output shaft's cross-section, which inserts between the clutch and bearing, ensuring tight contact and preventing grease scattering through frictional contact and a protruding piece for enhanced stability and assembly ease.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a cover or collar is used to prevent grease scattering, then grease scattering is prevented, but device complexity and cost increase

Engineering Contradiction:
Improveprevention of grease scatteringVSAvoidstructure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent introduces an annular shim as an intermediary component positioned between the bearing and the electromagnetic clutch. This shim acts as a mediator that blocks grease from migrating from the bearing to the clutch, solving the grease scattering problem without requiring complex covers or collars. The shim is a simple annular element that fits into the axial space already present in the assembly.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention extracts the grease-blocking function from complex cover structures and implements it through a simple annular shim. By separating the grease containment function from the overall housing structure, the solution achieves effective grease prevention with minimal additional complexity. The shim is positioned specifically at the interface where grease migration occurs, targeting the problem area precisely.

Inventive Principle:
Principle #2Taking out (Extraction)

2Reliability

If a cover or collar is used to prevent grease scattering, then grease scattering is prevented, but manufacturing cost increases

Engineering Contradiction:
Improveprevention of grease scatteringVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The annular shim is designed as a simple, inexpensive component that can be easily manufactured from common materials such as resin or metal. Unlike complex covers or collars that require精密 machining and assembly, the shim can be produced through simple molding or stamping processes, significantly reducing manufacturing costs while maintaining effective grease containment.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The shim serves as a low-cost intermediary element that provides the necessary grease barrier function. By using a simple annular structure rather than complex protective housings, the invention achieves reliable grease prevention at minimal manufacturing cost.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Power

If the output shaft rotates at high speed, then power transmission is efficient, but grease scatters from the bearing

Engineering Contradiction:
Improvepower transmission efficiencyVSAvoidgrease scattering
Core Design Contradiction:
PowerVSObject-generated harmful factors

Solution Approach 1:

The annular shim acts as a stationary intermediary barrier between the rotating bearing and the electromagnetic clutch. While the output shaft rotates at high speed for efficient power transmission, the shim remains in place and blocks the centrifugal force-driven grease migration, preventing grease from reaching the clutch without impeding the rotation or power transmission.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention converts the harmful effect of high-speed rotation (which causes grease to scatter) into a contained system where the grease is blocked by the shim. The high-speed rotation continues uninterrupted for efficient power transmission, while the shim transforms the potential harm of grease scattering into a controlled situation where grease remains confined to the bearing area.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

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

The shim effectively prevents grease from entering the electromagnetic clutch, reducing operational failures and simplifying assembly by ensuring precise positioning and secure attachment of the output shaft, thus enhancing the reliability and cost-effectiveness of the transmission device.

Implementation Method 1

the protruding piece is folded along the flat face so as to come frictionally contact with the flat face

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3751352B1Driving force transmission device and image forming apparatus
Publication Date: 2023.05.24 KYOCERA DOCUMENT SOLUTIONS INC
  • EP3751352B1 patent drawingFigure 1
  • EP3751352B1 patent drawingFigure 2
  • EP3751352B1 patent drawingFigure 3

AI summary

A driving force transmission device (47) includes a clutch (55), an output shaft (63), a bearing (71) and an annular shim (81). The clutch (55) is capable of being switched between a transmission of a rotational force and an interruption of the transmission of the rotational force. The output shaft (63) outputs the rotational force of the clutch (55). The bearing (71) supports an end portion (65) of the output shaft (63) with grease. The annular shim (81) is disposed around the end portion (65) of the output shaft (63) between the clutch (55) and the bearing (71). The shim (81) has a through hole (83) through which the end portion (65) of the output shaft (63) is inserted. The through hole (83) has the same shape as a cross section of the end portion (65) of the output shaft (63). A circumferential edge of the through hole (83) comes into tightly contact with an outer circumferential face of the end portion (65) of the output shaft (63).