Rotary shafts – gudgeons – housings – and flexible couplings for ro – Coupling facilitates relative axial motion between coupled... – Coupler includes antifriction rolling body engageable with...
Reexamination Certificate
1999-07-09
2001-06-05
Browne, Lynne H. (Department: 3629)
Rotary shafts, gudgeons, housings, and flexible couplings for ro
Coupling facilitates relative axial motion between coupled...
Coupler includes antifriction rolling body engageable with...
C464S179000, C464S906000
Reexamination Certificate
active
06241617
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to a propeller shaft assembly for connecting the front gearbox output to the drive input of the rear axle drive of a motor vehicle, especially of a passenger car.
Such propeller shaft assemblies known from the technical literature, for example Prof. Dipl.-Ing. Jörnson Reimpell: Fahrwerktechnik 1, 5
th
edition, Vogel-Verlag, p. 285, FIG. 3.1/21, comprise two propeller shaft portions which are connected to one another by a constant velocity plunging joint. At the ends of the propeller shaft portions intended to be connected to the front gearbox output and to the rear drive input, there are arranged universal joints. The propeller shaft serving to be connected to the gearbox output is associated with a resilient intermediate bearing which serves for additionally supporting the propeller shaft assembly on the floor assembly of the motor vehicle. The connection at the front end between the universal joint and the gearbox output is effected by a sleeve which is associated with a joint yoke of the universal joint and which comprises a bore with longitudinal toothing by means of which it is slid onto a correspondingly toothed shaft in the neck of the gearbox output. The constant velocity plunging joint connecting the two propeller shaft portions permits angular movements as well as displacing movements between the inner joint part and the outer point part, so that any changes in distance and position between the intermediate bearing and the rear drive input are compensated for. However, the resistance against such displacement is high.
In the assembly described, the smooth running characteristics are improved as compared to those propeller shaft assemblies wherein the between the two propeller shaft portions is a universal joint, but any movement vibrations generated by the gearbox, by the axle drive of the rear axle and resulting from the displacement of the articulation center of the universal joint, are transmitted by the front and rear propeller shaft portions into the attached assemblies. The intermediate bearing is also excited by vibrations.
The propeller shaft assembly is subject to movement vibrations and structure-borne sound vibrations introduced by the gearbox output and the rear drive input. In addition, as far as the rear propeller shaft portion is concerned, there are temporarily increased articulation angles. The problem is that constantly changing torque values and rotational speeds are transmitted from the front engine and gearbox unit to the rear axle. Load values suddenly increasing to 10 times the nominal torque, and rotational speeds up to 10,000 revolutions per minute are no rarity.
SUMMARY OF THE INVENTION
It is an object of the invention to propose a propeller shaft assembly which largely disconnects any vibrations introduced in the longitudinal direction and which, itself, does not generate any rotational vibrations.
In accordance with the invention, the objective is achieved by providing a propeller shaft assembly for connecting the front gearbox output to the drive input of the rear axle drive of a motor vehicle, such as a passenger car. The assembly includes a joint at each end for providing a connection to the front gearbox output and to the rear drive input, and includes plunging elements arranged near the joints to be connected to the front gearbox output and to the rear drive input. The plunging elements are provided in the form of a rolling contact member guide which permits plunging movements along a longitudinal axis and effect the transmission of torque. All of the joints are provided in the form of constant velocity fixed joints which only permit angular movements.
The advantage of the present embodiment is that any vibrations which can be transmitted by the front gearbox or by the rear axle drive into the propeller shaft assembly, and thus into the intermediate bearing, can be disconnected close to the vibration generating elements. There exist floating centering conditions.
According to a further embodiment, there are provided at least two propeller shaft portions, at least one intermediate bearing and one constant velocity fixed joint at each end for providing a connection to the front gearbox output and to the rear drive input, and one such joint between the two adjoining propeller shaft portions. Furthermore, the plunging elements are associated with the front propeller shaft portion and the rear propeller shaft portion. It is thus possible to keep the intermediate bearing largely free from vibration loads. This means that the intermediate bearing can be designed more easily for damping radial vibrations.
A particularly advantageous way of arranging the plunging elements consists in integrating same into the inner parts of the constant velocity fixed joints associated with the front gearbox output and the rear drive input.
According to a further embodiment of the invention, it is proposed that the joints each comprise an outer part with a cavity and two circumferentially distributed sets of outer running grooves which extend from the two open ends of the outer part in opposite directions in an undercut-free way in meridian planes around the longitudinal axis of the outer part. The inner part arranged in the cavity of the outer part is provided with inner running grooves which are arranged in accordance with the outer running grooves and which, like the outer running grooves, start from the same open ends and extend in an undercut-free way in meridian planes around the longitudinal axis. Between the outer part and the inner part, there is arranged a joint cage whose windows are open towards the outer running grooves and the inner running grooves. Said windows accommodate joint balls of which one each is arranged in a pair of outer and inner running grooves.
Said constant velocity fixed joints are advantageous in that they run in a low-friction way and even at larger articulation angles, they have a long service life. In particular, this is the case if, per type of running groove, there are used at least five balls, i.e., a total of at least ten joint balls. The running characteristics are then smoother, too, because the mass of said joint balls is much smaller than in the case of the usual joints which are provided with six balls. Furthermore, the torque transmitting capacity is improved at higher articulation angles because more balls participate in the transmission of torque. Smooth running characteristics are particularly important when using such joints in the propeller shaft of a passenger car where high rotational speeds occur.
REFERENCES:
patent: 5582546 (1996-12-01), Welschof
patent: 5611733 (1997-03-01), Jacob et al.
patent: 5634853 (1997-06-01), Smith
patent: 5813917 (1998-09-01), Wakamatsu et al.
patent: 5899814 (1999-05-01), Murillo
patent: 2 212 882 (1989-02-01), None
patent: 2 289 929 (1995-06-01), None
patent: 2 311 758 (1997-08-01), None
patent: 2 311 117 (1997-09-01), None
Pro. Dipl.-ing Jörnson Reimpell: Fahrwerktechnik 1, 5th Edition, Vogel-Verlag, p. 285, Figure 3.1/21.
Binda Greg
Browne Lynne H.
GKN Lobro GmbH
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