Nonuniformity of Isometric Properties of Automotive Driveshafts

Mihai Bugaru,Andrei Vasile

doi:10.3390/computation9120145

Abstract

This paper presents an analysis of the CVJ (constant velocity joint) of automotive driveshafts from a point of view concerning the nonuniformity of isometric properties. In the automotive industry, driveshafts are considered to have constant velocity through its joints: free tripode joints and fixed ball joints, which has been proved by Mtzner’s indirect method and Orain’s direct method for tripod joint. Based on vectorial mechanics, the paper proved the quasi-isometry of velocity for polypod joints such as fixed ball joints. In the meantime, it was computed that the global nonuniformity of constant velocity joints for modern driveshafts based on the Dudita-Diaconescu homokinetic approach for the driveshafts. The nonuniformity of the velocity isometry of driveshafts was computed as a function of the input angular velocity of the driveshaft, angular inclination between the tripod–tulip axis and the midshaft axis and the angular inclination between the bowl axis and midshaft axis. The main aim of this article is how to improve the geometric and kinematic approach to add an important correction when designing the driveshaft dynamics prediction such as: forced torsional vibrations, forced bending–shearing vibrations, and coupled torsional–bending vibrations for the automotive driveshaft in the regions of specific resonances such as principal parametric resonance, internal resonance, combined resonance, and simultaneous resonances. By the way it is added, there are important corrections for the design of driveshafts, for the torsional dynamic behavior prediction, and for bending–shearing dynamic behavior of the driveshafts in the early stages of design. The results presented in the article represent a starting point for future research on dynamic phenomena in the area mentioned previously.

Highlights

Let us look inside the components of such a mechanism by looking at the Figure 2, which consists of (a) the bowl-balls joint fixed assembled by the car wheel; (b) the midshaft axis; (c) the tulip–tripode joint that allows for axial plunging of the tripod in the tulip and the plunging assembled in the gear box
The first to introduce the concept of a constant velocity joints (CVJs) was Metzner, in 1967, who is mentioned in the literature [4] as the creator of the first indirect method (FIM) for proving constant in the literature [4] as the creator of the first indirect method (FIM) for proving constant velocity for special Hooke joints [1], based on the idea that “the generators of a constant velocity for special Hooke joints [1], based on the idea that “the generators of a constant velocity joint must be mirror images in space” [1] (p. 61)
That time, the nineteenties, it wasitconsidered that athat nonuniformity fromfrom a kinematic isometry of theoftripode joints seventies, was considered a nonuniformity a kinematic isometry the tripode of was acceptable; when an improvement of is a huge gain in the automojoints of 5–7% was acceptable; when an improvement of 1% is a huge gain in the tive industry, and is and it is is noitlonger acceptable

Summary

Introduction

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State of the Art

Nonuniformity of Geometric

Findings

Conclusions