Ntn Corporation

Bridgestone Corporation

Yoshihiko Hayama

Haruo Nagatani

Keisuke Sone

Takashi Nozaki

Hiroyuki Hakamata

A cross groove constant velocity universal joint for a drive shaft or a propeller shaft of an automotive vehicle includes an inner ring and an outer ring each having ball grooves which are alternately slanted in respective directions opposite to each other while alternating with each other in a direction circumferentially thereof. Torque transmission balls are positioned at a crossing area where each of the ball grooves in the inner ring and the associated ball groove in the outer ring are crossed with each other. A cage is provided to retain the torque transmission balls. The number of torque transmission balls is ten, and a crossing angle between the axis of the inner or outer ring and each of the ball grooves in the inner or outer ring is within the range of 10 to 15&#xb0; or 6 to 9&#xb0; for the drive shaft or the propeller shaft, respectively.

Cross groove constant velocity universal joint

A shaft coupling includes plates fitted on ends of input and output shafts, respectively. A plurality of guide grooves are formed in the opposed surfaces of the plates, respectively, so that each of the grooves extends perpendicular to the corresponding groove formed in the other plate. A steel ball is disposed between each pair of guide grooves of the plates at a portion where the pair of grooves cross each other. When the steel balls are pushed by the driving plate, they push the driven plate while rolling in the guide grooves, with their movements restricted by a retainer in the radial direction of the plates. Thus, large power can be smoothly transmitted between the rotary members with less frictional resistance. The offset amount can be changed easily. Between the plates, there are only the steel balls and the retainer.

Shaft coupling

The width (L) in the circumferential direction of the outer surface,of an inner joint member,is L&gE;3.5 mm. When the assembly angle (&thgr;,) of the torque transmitting ball,is set to 50&deg;, the width (W) in the axial direction is set so that the ratio Rw (&equals;W/PCD,) between the width (W) in the axial direction and the pitch circle diameter (PCD,) of the teeth of an engagement portion,lies within the range of 0.57<Rw&lE;0.95. Thus, while enabling the assembly of the torque transmitting ball at the assembly angle &thgr;,&equals;50&deg;, cold forging on the inner joint member,is made possible, thereby reducing the processing cost. By reducing the width (W) in the axial direction as much as possible, the weight, dimension, and material cost can be reduced.

Propeller shaft and constant velocity universal joint for a propeller shaft

In an inner joint member (,) that has eight guide grooves (,) formed to extend in the axial direction located at equal intervals in the circumferential direction on the outer circumference (,) of spherical shape and a fitting portion (,) provided on the inner circumference for the purpose of coupling with a stub shaft, ratio of width W between the center of curvature O,of the outer circumference (,) of spherical shape and the end face to the pitch circle diameter Ds of the fitting portion (,) is set as W/D,>0.27, thereby making it possible for a plunging constant velocity universal joint for propeller shaft of the vehicle to be lighter in weight, more compact and is capable of contributing to the improvement of the NVH characteristic of the vehicle.

Growing community of inventors

Iwata, Japan

Yoshihiko Hayama