Double Cardan Joint Protection Cap Structure for Lower Wear

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Solution Overview

Problem

Existing double Cardan joints suffer from significant wear due to the use of flexible material protection caps, which are designed to allow rotation around cross shafts, leading to reduced durability.

Innovation Solution

A double Cardan joint design featuring rigid plastic protection caps and a support bearing system with a spherical surface and truncated cone shape, along with a tubular casing and coupling sleeve, to minimize wear and maintain efficient rotation while adhering to standard spatial constraints.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If flexible material protection caps are used to allow rotation around cross shafts, then the joint can rotate freely, but the caps are subjected to relatively great wear

Engineering Contradiction:
Improverotation capabilityVSAvoidwear resistance
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The protection cap is divided into two distinct parts: a rigid plastic cap that provides structural support and wear resistance, and a flexible bellows element that enables rotation. This segmentation allows each part to fulfill its specific function - the rigid part resists wear while the flexible part provides rotational freedom.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The protection cap combines two different materials with complementary properties: rigid plastic material for wear resistance and structural integrity, and flexible material for rotational movement. This composite structure resolves the contradiction by allowing both rotation capability and wear resistance to coexist in different parts of the same component.

Inventive Principle:
Principle #40Composite materials

2Reliability

If rigid plastic protection caps are used to reduce wear, then durability is improved, but rotation around cross shafts may be restricted

Engineering Contradiction:
Improvewear resistanceVSAvoidrotation capability
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The protection cap is divided into two distinct parts: a rigid plastic cap that provides structural support and wear resistance, and a flexible bellows element that enables rotation. This segmentation allows each part to fulfill its specific function - the rigid part resists wear while the flexible part provides rotational freedom.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The protection cap combines two different materials with complementary properties: rigid plastic material for wear resistance and structural integrity, and flexible material for rotational movement. This composite structure resolves the contradiction by allowing both rotation capability and wear resistance to coexist in different parts of the same component.

Inventive Principle:
Principle #40Composite materials

Data Source

PatentEP4015858B1Double cardan joint
Publication Date: 2023.08.09 AMA SPA
  • EP4015858B1 patent drawingFigure 1
  • EP4015858B1 patent drawingFigure 2
  • EP4015858B1 patent drawingFigure 3

AI summary

A double Cardan joint has a driving fork (2); a driven fork (4); a central body (6) connected to the two forks (2, 4) by means of respective cross shafts (8, 11); a first protection cap (16) connected to the central body (6); and a second protection cap (29) connected to the driven fork (4) and coupled to the driven fork (4) in a rotary manner so as to rotate, relative to the driven fork (4), around a rotation axis (32), which is transverse, in particular orthogonal, to a longitudinal axis (5) of the driven fork (4) .