Tripod Joint Roller Bore Design for Vibration Reduction
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Solution Overview
Problem
Conventional tripod joints experience increased wear, power loss, and vibration due to relative sliding in rolling contacts, which affects the service life and smooth operation of motor vehicle drive shafts.
Innovation Solution
A tripod joint design featuring elongate tracks on the outer joint element and radial axle journals with pivotable rollers, and a bore configuration with cylindrical and constriction sections to minimize vibration by allowing controlled displacement and maintaining alignment during angling, reducing friction and contact stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional tripod joints are used with shafts articulated at working angles, then the joint can transmit power between angled shafts, but relative sliding occurs in the rolling contacts leading to increased wear, power loss, and vibration
Solution Approach 1:
The invention applies spherical contact surfaces between the rollers and the outer joint element, replacing conventional cylindrical or flat contacts. The rollers have spherical outer surfaces that engage with spherical recesses in the outer joint element, ensuring pure rolling motion without sliding even when shafts are articulated at working angles. This spherical geometry maintains constant contact and eliminates the relative sliding that causes wear and vibration in conventional designs.
2Stress or pressure
If ball/ball contact surface is used between axle journal and roller to distribute Hertzian stress, then contact area is increased, but friction and shaking are intensified
Solution Approach 1:
The invention replaces the ball/ball contact configuration with spherical roller surfaces engaging spherical recesses. This geometric change transforms the contact mechanics from point contact with high stress concentration to distributed surface contact that maintains pure rolling. The spherical geometry ensures that the contact points naturally align with the motion path, eliminating the shaking and excessive friction observed in ball/ball contact designs while still distributing stresses effectively.
3Ease of manufacture
If constrictions are made in the bore of the roller for assembly aid, then the roller is secured on the axle journal during assembly, but these constrictions do not come into contact during operation and only serve as assembly aids
Solution Approach 1:
The invention designs the bore of the roller with a stepped configuration that serves dual purposes: the narrower section acts as both an assembly aid for securing the roller on the axle journal and as a functional element that comes into contact during operation. This multi-functional design eliminates the need for separate assembly features while maintaining operational effectiveness, reducing overall device 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
The design minimizes vibration excitation and maintains low friction, enhancing the service life and driving comfort of motor vehicles by distributing displacement paths effectively and limiting noise-critical movements.
Implementation Method 1
the roller being in the associated track in the axial direction of the outer joint member is slidably received... This rolling contact between roller and track of the outer joint member
Implementation Method 2
a constriction section is provided at least on one side of the cylindrical section and adjoining it, which engages behind the ball end faces in order to limit the displacement movement
Implementation Method 3
a cylinder/ball contact surface is provided in the cylindrical section
Data Source
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AI summary
The invention relates to a tripod joint (1), comprising an outer joint element (2) having several axially extending elongate tracks (4) formed therein and distributed over the internal periphery thereof, an inner joint element (3) having several radial journals (5) distributed over the external periphery thereof, at least a number of rollers (6) corresponding to the number of journals (5), wherein each roller (6) is pivotably retained by a central bore (20) on the associated journal (5) and engages with the elongate track (4), wherein the roller (6) is movable in the associated track (4) in the axial direction of the outer joint element (2), wherein each journal (5) has two outer, diametrically opposed spherical end faces (16) in the circumference thereof for engagement in the bore (20). The articulation joint is characterized in that the bore (20) has a cylindrical section (9c) for engagement with the spherical end faces (16) in order to mount the roller (6) such as to be displaceable relative to the journal (5), and at least one constricted section (9d, 9e) which adjoins the cylindrical section (9c) in the axial direction, forming a continuous transition on one side of the cylindrical section (9c), and engages behind the spherical end faces in order to limit the displacement movement.