Sleeve Yoke Fixing Surface Segmentation for Short Cardan Shafts

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Solution Overview

Problem

Existing methods for fixing sleeve yokes to broaching benches for cutting spline profiles in cardan shafts are inadequate for extremely short shafts, as they require a circular fixing surface that interferes with the protective cover seal, leading to reduced axis distance, excessive chip removal, and decreased strength due to machining on the external diameter.

Innovation Solution

Creating fixing surfaces on the heights of the ear lugs of the sleeve yoke, allowing for a non-circular arc angle of 360° to 150°, which reduces chip removal and positions the fixing surface away from the protective cover seal, enabling shorter cardan shafts with increased strength and stiffness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If a circular fixing surface is created on the external diameter of the body, then the fixing surface provides adequate contact area, but excessive chip removal is required and the axis distance cannot remain under a certain value

Engineering Contradiction:
Improvefixing surface areaVSAvoidchip removal amount
Core Design Contradiction:
Area of stationary objectVSLoss of substance

Solution Approach 1:

The invention divides the fixing surface into two separate locations: one on the external diameter of the body and another on the internal diameter of the body. This segmentation allows each fixing surface to be smaller and positioned optimally, reducing the total chip removal required while maintaining adequate contact area for fixing the sleeve yoke to the broaching bench

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention transitions from a single circular fixing surface on the external diameter to a dual-location fixing system that utilizes both external and internal diameters. This dimensional change in the fixing surface configuration reduces the sliding length requirement and allows for shorter cardan shafts while minimizing chip removal

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Area of stationary object

If a circular fixing surface is created on the external diameter of the body, then the fixing surface provides adequate contact area, but the machining time increases due to larger diameter body

Engineering Contradiction:
Improvefixing surface areaVSAvoidmachining time
Core Design Contradiction:
Area of stationary objectVSLoss of time

Solution Approach 1:

By segmenting the fixing surface into two locations (external and internal diameters), the required contact area at each location is reduced, allowing for smaller diameter bodies to be used. This segmentation enables faster machining times while still providing adequate fixing surface area for the broaching operation

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention changes the geometric parameters of the fixing surface configuration, transitioning from a single large circular surface to two smaller surfaces at different locations. This parameter change allows for reduced body diameter and consequently shorter machining times while maintaining the necessary fixing surface area

Inventive Principle:
Principle #35Parameter changes

3Area of stationary object

If the fixing surface is created on the external diameter of the body, then the fixing surface provides adequate contact area, but the strength of the cardan shaft is reduced in the fixing area

Engineering Contradiction:
Improvefixing surface areaVSAvoidcardan shaft strength
Core Design Contradiction:
Area of stationary objectVSStrength

Solution Approach 1:

The invention segments the fixing surface requirement into two locations, allowing the external diameter fixing surface to be smaller and not compromise the overall strength of the cardan shaft. The internal diameter fixing surface provides additional support, distributing the stress and maintaining strength in the fixing area

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention creates a recess or cavity in the internal diameter of the body beforehand, which serves as a pre-prepared fixing surface location. This preliminary action allows for the fixing surface to be created without compromising the strength of the external diameter, as the internal fixing surface is prepared in advance

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP2385263B1A high-strength sleeve yoke having fixing surfaces with reduced machining chipping surface and corresponding production method
Publication Date: 2016.08.03 TIRSAN KARDAN SANAYI & TICARET ANONIM SIRKETI
  • EP2385263B1 patent drawingFigure 1
  • EP2385263B1 patent drawingFigure 2
  • EP2385263B1 patent drawingFigure 3

AI summary

The invention relates to the leaning surfaces wherein the sleeve yoke (11) is attached to the broach bench for the process of cutting spline threads (12) in the inner section of the sleeve yoke (11); and is characterised in that; it comprises heights (14) formed on the lobe (13) of the said sleeve yoke (11) and the leaning surfaces (15) formed on these heights (14).