Power Transmission Device Shaft Alignment via Bearing Segmentation

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Solution Overview

Problem

The radial load imparted by chain tension on a rotary shaft in power transmission devices causes misalignment, leading to a shortened device lifetime.

Innovation Solution

A power transmission device design that includes a joint linking the rotary shaft to the driving sprocket, where the driving sprocket is supported by a bearing secured to a stationary member, preventing radial loads from affecting the rotary shaft and maintaining alignment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the rotary shaft directly supports the driving sprocket to transmit torque to the auxiliary device, then the structure is simple and compact, but the radial load from chain tension causes misalignment of the rotary shaft and shortens device lifetime

Engineering Contradiction:
Improvestructural simplicityVSAvoidshaft alignment stability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent divides the support function into two separate components: the rotary shaft for torque transmission and the bearing for radial load support. The driving sprocket is no longer directly supported by the rotary shaft but by a bearing that is secured to a stationary member, separating the torque transmission function from the radial load support function.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The bearing acts as an intermediary component between the driving sprocket and the stationary member. It supports the driving sprocket and absorbs the radial load from chain tension, preventing this load from being transmitted to the rotary shaft while still allowing torque transmission through the joint.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the driving sprocket is supported by a bearing secured to a stationary member, then the rotary shaft is protected from radial loads and misalignment is prevented, but the device complexity increases

Engineering Contradiction:
Improveshaft alignment stabilityVSAvoidstructural complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The bearing serves multiple functions: it supports the driving sprocket, absorbs radial loads from chain tension, and prevents misalignment of the rotary shaft. By consolidating these functions into a single component secured to the stationary member, the patent avoids the need for additional complex support structures.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The joint is positioned within the hollow portion of the rotary shaft, creating a nested arrangement where the joint (for torque transmission) is contained within the rotary shaft structure. This nested configuration allows compact integration of multiple functions without increasing overall device complexity.

Inventive Principle:
Principle #7Nested doll (Nesting)

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 prevents misalignment and extends the lifetime of the device by isolating the rotary shaft from radial loads, ensuring compactness and reducing production costs.

Implementation Method 1

a bearing (55) supporting the driving sprocket (51)

Methodology Applied
Scientific EffectBall bearing: Ball Bearing

Data Source

PatentEP2390533B1Power transmission device
Publication Date: 2019.04.24 NISSAN MOTOR CO LTD
  • EP2390533B1 patent drawingFigure 1
  • EP2390533B1 patent drawingFigure 2
  • EP2390533B1 patent drawingFigure 3~4

AI summary

A power transmission device is used to distribute torque from a power source (ENG) to an external device and an auxiliary device. The power transmission device is comprised of a first bearing (55) and a second bearing (12) both secured to a stationary member, a first sprocket (51) rotatably supported by the first bearing (55), a second sprocket (52) capable of being drivingly coupled with the auxiliary device, a chain (53) coupling the first sprocket (51) with the second sprocket (52), a rotary shaft (5) rotatably supported by the second bearing (12), which is drivingly coupled with the power source and drivingly engageable with the external device to transmit a first part of the torque to the external device, and a joint drivingly linking the rotary shaft (5) with the first sprocket (51) to transmit a second part of the torque to the first sprocket (51).