Propeller Shaft Snap Ring Assembly With Visual Engagement Check

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

The existing power transmitting shaft structures, where snap rings are fitted into and engaged with stopper grooves of constant-velocity joints, make it impossible to visually check the engagement-stop state from the outside, leading to potential improper assembly and risk of snap ring pulling-out.

Innovation Solution

A power transmitting shaft design featuring a shaft member with a joint member having a flexible joint and a tubular portion with a retaining ring inserting portion and fitting groove, allowing a retaining ring made of elastic material to be inserted and fitted, enabling visual verification of the engagement-stop state and preventing snap ring pulling-out.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of stationary object

If a conventional power transmitting shaft is used, then the structure is simple, but the shaft bends under its own weight over long distances, limiting the number of booms that can be supported

Engineering Contradiction:
Improveshaft lengthVSAvoidshaft bending
Core Design Contradiction:
Length of stationary objectVSStability of the object's composition

Solution Approach 1:

The power transmitting shaft is divided into multiple modular sections that can be connected in series. Each section has a standardized interface allowing them to be assembled to different lengths while maintaining structural integrity. This segmentation allows the shaft to span longer distances between booms without excessive bending, as each module contributes to the overall stiffness and load distribution.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The shaft is constructed using composite materials with high strength-to-weight ratio, combining materials that provide both structural rigidity and minimal self-weight. This composite construction reduces the bending moment caused by the shaft's own weight over long spans, enabling longer distances between booms while maintaining stability and supporting the required number of booms.

Inventive Principle:
Principle #40Composite materials

2Stability of the object's composition

If the shaft diameter is increased to reduce bending, then the weight of the shaft increases, requiring stronger and heavier booms

Engineering Contradiction:
Improveshaft bending resistanceVSAvoidshaft weight
Core Design Contradiction:
Stability of the object's compositionVSWeight of moving object

Solution Approach 1:

The shaft utilizes composite materials that provide high bending resistance without proportionally increasing weight. These materials offer superior specific stiffness (stiffness per unit weight), allowing the shaft to resist bending over long spans while keeping the weight increase minimal compared to traditional solid shaft designs.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The shaft design incorporates varying cross-sectional properties along its length, with thicker or reinforced sections at critical locations (such as near boom connections) and thinner sections in intermediate areas. This localized reinforcement provides bending resistance where needed while minimizing overall weight, avoiding the need to uniformly increase the shaft diameter throughout its entire length.

Inventive Principle:
Principle #3Local quality

3Quantity of substance

If the distance between booms is increased, then fewer booms are needed, but the shaft must support greater spans, increasing bending and requiring more booms

Engineering Contradiction:
Improvenumber of boomsVSAvoidshaft bending between booms
Core Design Contradiction:
Quantity of substanceVSStability of the object's composition

Solution Approach 1:

The modular shaft design allows for optimized spacing between booms by providing standardized connection interfaces that maintain structural integrity at regular intervals. This enables longer spans between booms to be achieved while keeping the shaft's bending within acceptable limits, as each modular section contributes to the overall stiffness and load distribution along the span.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The use of high-specific-stiffness composite materials enables longer spans between booms without excessive bending. These materials allow the shaft to maintain adequate stiffness over extended distances, reducing the number of booms required while preventing the shaft from bending excessively between support points.

Inventive Principle:
Principle #40Composite materials

4Weight of moving object

If a hollow shaft is used to reduce weight, then material strength is reduced, but this limits the shaft's ability to support long spans

Engineering Contradiction:
Improveshaft weightVSAvoidshaft strength
Core Design Contradiction:
Weight of moving objectVSStrength

Solution Approach 1:

The hollow shaft is constructed using composite materials that provide exceptional strength-to-weight ratio. These materials allow the hollow structure to maintain adequate bending strength and stiffness while keeping the weight low. The composite construction compensates for the reduced material quantity in the hollow design, ensuring the shaft can support long spans without excessive bending.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The hollow shaft design incorporates localized reinforcement at critical sections where bending moments are highest, such as near boom connections. This may include thickened walls or integrated stiffening elements at these locations while maintaining the hollow lightweight structure in intermediate sections. This selective reinforcement maintains overall strength while preserving weight advantages.

Inventive Principle:
Principle #3Local quality

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 design allows for visual verification of the snap ring engagement-stop state and prevents snap ring pulling-out, ensuring proper assembly and secure connection between the shafts.

Implementation Method 1

a retaining ring made of elastic material, wherein the retaining ring can be inserted into the tubular portion body from the retaining ring inserting portion

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3763959B1Power transmitting shaft
Publication Date: 2023.06.28 ASTEMO LTD
  • EP3763959B1 patent drawingFigure 1
  • EP3763959B1 patent drawingFigure 2
  • EP3763959B1 patent drawingFigure 3~4

AI summary

A propeller shaft (1), as a power transmitting shaft, of the present invention is configured such that a snap ring (8) as a retaining ring can be inserted inwards into a first penetration slot (31) formed at a tubular portion body (33) of a tubular portion (30) from a radial direction outer side. With this, good workability of assembly of the snap ring (8) is secured. Further, an engagement-stop state of a second shaft (3) by the snap ring (8) can be visually checked from the outside through the first penetration slot (31), then check of an engagement state by the snap ring (8) can be made.