Universal Joint Structure for Flexing Angle Limitation

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Solution Overview

Problem

Existing universal joints for propeller shafts face issues with weight increase and interference due to projecting portions, which limit the flexing angle and cause blockages during vehicle collisions, and require larger bolt diameters, leading to increased weight and clearance issues.

Innovation Solution

A universal joint design featuring flexing limiting portions that restrict the flexing angle through mutual contact between the base end portion and the spider, eliminating the need for projecting portions on the yoke arms and allowing the flange to maintain a smaller size and weight, with the spider's flange portion supporting both sealing and flexing functions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If projecting portions are formed on the lateral sides of the yoke arms to limit the flexing angle, then the flexing angle is limited, but the size of the yoke becomes larger and its weight increases

Engineering Contradiction:

Improveflexing angle limitationVSAvoidyoke weight

Core Design Contradiction:

ReliabilityVSWeight of moving object

Solution Approach 1:

The patent merges the flexing angle limiting function with the existing yoke structure by forming the limiting portions at the base end portions that contact the spider, rather than adding separate projecting portions on the lateral sides. This integration allows flexing angle limitation while avoiding additional weight from protruding structures.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

Instead of adding projecting portions that extend outward from the yoke arms, the patent inverts the approach by utilizing the base end portions that naturally contact the spider. The limiting function is achieved through the configuration of these existing contact surfaces rather than through additional outward-protruding elements.

Inventive Principle:

Principle #13The other way round (Inversion)

2Reliability

If projecting portions are formed on the lateral sides of the yoke arms, then the flexing angle is limited, but the pitch circle diameter of the bolts must be enlarged, causing weight increase and clearance issues

Engineering Contradiction:

Improveflexing angle limitationVSAvoidflange outer diameter

Core Design Contradiction:

ReliabilityVSArea of stationary object

Solution Approach 1:

The patent extracts the flexing angle limiting function from the lateral projecting portions and relocates it to the base end portions at the center of the yoke. This separation allows the flange and bolt holes to maintain their original dimensions without interference, eliminating the need to enlarge the pitch circle diameter.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the spatial dimension where the limiting function is implemented - moving from lateral projections (radial dimension) to base end portion configurations (axial dimension). This dimensional shift allows the flange to maintain its original size while still achieving flexing angle limitation.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Data Source

PatentUS11306786B2Universal joint and propeller shaft

Publication Date: 2022.04.19 HONDA MOTOR CO LTD

AI summary

A cross joint comprises a flange yoke and a stab yoke, each comprising a based end portion and a pair of arm portions having a shaft hole and extending from both sides of the base end portion, and a spider having a first shaft fitted into the shaft hole of the flange yoke and a second shaft fitted into the shaft hole of the stab yoke, wherein the cross joint further comprises a flexing limiting portion, which limits a flexing angle of the cross joint due to mutual contact of a protruding portion of the base end portion and a flange portion of the spider when the flange yoke is flexed to a predetermined angle.