Universal Joint Shaft with Nested Intermediate Sleeve for Compact Torque Transmission
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Solution Overview
Problem
Joint shafts with axial length compensation are too long for small installation spaces in roll mills, requiring a significant axial overlap to transmit torque reliably, which can lead to excessive forces and premature wear.
Innovation Solution
A universal joint shaft design featuring pivot joints and a central part with length compensation, including a tubular shaft element with internal gearing and a rod-shaped element with external gearing, along with intermediate sleeves and axial stops, allowing for torque transmission in both extended and retracted states while minimizing axial length.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If axial length compensation is implemented using traditional telescopic shaft elements with gearings, then the joint shaft can transmit torque reliably in extended and retracted states, but the axial length becomes too long for small installation spaces
Solution Approach 1:
The second shaft element is nested inside the first shaft element in a telescopic arrangement, allowing the joint shaft to compact its axial length when retracted while maintaining the capability to extend when needed. The intermediate sleeve is similarly nested between the two shaft elements, optimizing the compactness of the overall structure.
Solution Approach 2:
The axial length of the joint shaft is made variable through the telescopic mechanism, allowing it to change between a short retracted state for compact installation and an extended state for torque transmission. The spiral bevel gearings enable this parameter change while maintaining torque transmission capability across different lengths.
2Length of moving object
If the axial overlap between shaft elements is reduced to shorten the joint shaft, then the installation space is reduced, but the surface pressures and forces on the gearings become excessively high
Solution Approach 1:
An intermediate sleeve is introduced as a mediator between the first and second shaft elements. This intermediate sleeve carries additional spiral bevel gearings that engage with the shaft elements, distributing the torque transmission load across multiple gearing stages and reducing the surface pressures on individual gear teeth while maintaining compact axial dimensions.
Solution Approach 2:
The torque transmission path is segmented into multiple stages through the intermediate sleeve with its own set of spiral bevel gearings. This segmentation allows the total torque load to be distributed across several smaller gearing engagements rather than concentrated in a single large gearing, reducing surface pressures.
3Stress or pressure
If the axial overlap between shaft elements is increased to reduce surface pressures, then the joint shaft becomes too long for small installation spaces
Solution Approach 1:
The intermediate sleeve is nested between the first and second shaft elements, allowing the multi-stage gearing system to be packed into a compact axial space. This nesting arrangement enables sufficient axial overlap for torque transmission while keeping the overall joint shaft length suitable for small installation spaces in roll mills.
4Adaptability or versatility
If the joint shaft is designed with telescopic functionality for length compensation, then it can adapt to different installation spaces, but the structural complexity increases
Solution Approach 1:
The intermediate sleeve serves multiple functions simultaneously: it acts as a structural connector between the two shaft elements, provides additional torque transmission through its spiral bevel gearings, and enables the telescopic motion for length compensation. This multi-functionality reduces the need for separate components and simplifies the overall structure despite the telescopic capability.
Solution Approach 2:
The intermediate sleeve merges the functions of structural support, torque transmission, and telescopic motion control into a single component. The spiral bevel gearings on the intermediate sleeve are combined with the shaft element gearings to create an integrated torque transmission system that also enables length compensation, reducing structural complexity.
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
Enables reliable torque transmission in compact spaces with reduced wear and force, maintaining maximum transmittable torque in all states, and preventing jamming and buckling through defined retraction and centering mechanisms.
Implementation Method 1
The first shaft element (6) comprises a first spiral bevel gearing (9) with inner teeth, which are distributed over the circumference and extend in the direction of the longitudinal axis, and the second shaft element (7) comprises a second spiral bevel gearing (12) with outer teeth
Implementation Method 2
provided in the central part (4), or when the end part (22) is designed with length compensation, in the end part (22), are axial stops which delimit an extending of the second shaft element (7)
Implementation Method 3
provided in the central part (4), or when the end part (22) is designed with length compensation, in the end part (22), are radial guide means which, in a radial manner, guide the intermediate sleeve (8)
Data Source
AI summary
A joint shaft, in particular a universal joint shaft, has first and second axial connection ends and a central part that connects the two connection ends to one another in a torsionally rigid and pivotable manner. At least one intermediate sleeve is provided between a first and a second shaft element with internal gearing having inner teeth, which are distributed over the circumference and extend in the direction of the longitudinal axis, and external gearing with outer teeth, which are distributed over the circumference and extend in the direction of the longitudinal axis. The sleeve is longitudinally displaceable relative to the first shaft element and to the second shaft element and is attached directly or indirectly in a torsionally rigid manner to the first shaft element by way of the intermediate sleeve external gearing and to the second shaft element by way of the intermediate sleeve internal gearing.