30% lighter than conventional driveshafts, contributing to lower fuel consumption
NTN Corporation (hereafter, NTN) has developed the “Lightweight Driveshaft for FR vehicle” that has been optimized for rear-wheel drive layouts commonly used in luxury vehicles.
As automobile fuel consumption regulations become more stringent in Europe and other countries around the world in recent years, reducing CO2 emissions has emerged as a major challenge for car makers. Accordingly, there is increased lighter-weight demand for driveshafts for rear-wheel drive layouts of luxury vehicles (hereafter, rear driveshafts) with the aim of reducing fuel consumption.
Development of this driveshaft for rear-wheel drive layouts has resulted in drastic reductions in weight saving. Until now, the constant velocity joints (hereafter, CVJ) that had been optimized for the front wheels in a front-wheel drive layout had also been used for the rear driveshafts. CVJ for the front wheels cover the vertical stroke due to suspension movement, as well as the steering angle when turning the steering wheel, and is designed to transmit torque smoothly at the same constant speed up to angles of 47 to 50°. Yet rear driveshafts generally only need to cover the vertical stroke due to suspension movement and do not require such a large operating angle, with reductions in weight expected.
The newly developed “Lightweight Driveshaft for FR vehicle” is designed exclusively for rear wheels with the limited operating angle required for the rear driveshafts. The fixed CVJ on the tire side and the sliding CVJ on the differential side have been newly designed, the wall thickness of the hollow shaft connecting them has been reduced as far as possible, and a compact boot has been used to cover CVJs. As a result, the weight of each driveshaft has been reduced by 2.2 kg (approximately 30%) from conventional driveshafts. In addition to the CVJ, the shape of all main parts has also been optimized to ensure the required load capacity while also achieving a lighter, more compact design.
The developed product will be marketed for the luxury vehicle market mainly in Europe and Japan to contribute to lower fuel consumption and better ride comfort of automobiles.
NTN will exhibit the developed product at the “44th Tokyo Motor Show 2015” to be held at Tokyo Big Sight from October 29 to November 8.
|(1) Lightweight||each driveshaft is 2.2 kg lighter|
(approximately 30% reduction compared to conventional products)
|(2) More compact||3 to 5% reduction in CVJ outer ring diameter compared to conventional products|
Rear driveshafts of rear-wheel drive and four-wheel drive automobiles