GB2044394A

GB2044394A - Vibration Suppressor for Rotating Shafts

Info

Publication number: GB2044394A
Application number: GB8002042A
Authority: GB
Original assignee: Goetze GmbH
Current assignee: Goetze GmbH
Priority date: 1979-01-25
Filing date: 1980-01-22
Publication date: 1980-10-15
Also published as: DE2902752A1; IT1126456B; FR2447487A1; IT7927763A0

Abstract

A mounting flange 2 is fitted on the shaft, e.g. the propeller shaft of a motor vehicle, and carries a flywheel ring 5 by way of rubber bodies 8 which are pre-stressed and vulcanized to arms 3 of the flange 2 and radial faces 10 of chambers 7 formed in the flywheel ring 5. The rubber bodies 8 and the radial ends of the arms 3 are spaced by a gap 12 from the chamber head 11 which serves as an abutment to limit bulging of the rubber bodies under load. The arms may instead be on the flywheel ring and project into chambers in the hub. Alternatively the hub and ring may be axially spaced. <IMAGE>

Description

SPECIFICATION Vibration Suppressor for Rotating Shafts The invention relates to a vibration suppressor for reducing torsional and/or bending vibrationain rotating shafts and in particular universal-joint shafts for motor vehicles, comprising a mounting flange encircling the shaft and connectable thereto and having a plurality of arms pointing radially outwards, and a flywheel ring connected to the mounting flange via rubber bodies.

For damping torsional vibrations, in particular in drive lines of motor vehicles, flexible shaft couplings are frequently employed, these serving at the same time as swivel joint. Due to the transmission of the entire torque via these shaft couplings, which are generally equipped with rubber springs, only a slight damping action occurs. Almost complete suppression of torsional and bending vibrations occurring in the universaljoint shaft system is possible only with special vibration suppressors.

The basic principle of vibration suppressors is as follows:- These suppressors frequently consist of a hub, a flywheel ring and elastic bodies arranged between the two parts and vulcanized or cemented onto or forced between the parts, the flywheel ring, in contrast to a rotationally flexible shaft coupling, having a degree of freedom of movement which is at least three-dimensional and not being substantially impaired in its vibration behaviour by any compelling force, for example a torque to be transmitted.

There is already known from German Patent Specification 710,556 a vibration damping device comprising a hub having two arms disposed opposite one another and projecting radially outwards, and a flywheel mass surrounding these arms. Pretensioned elastic intermediate elements, which are in the form of sectors, are supported by one of their ends against radial abutments of the mass ring and by their other ends against arms projecting radially from the shaft or the hub into the ring space. The pretensioning is effected by means of pressure plates arranged between the elastic elements and which are forced in the circumferential direction against the ends of the elastic elements by means of expanding members extending parallel to the axis of the shaft and mounted to pivot about their axes.This .construction is purely a torsional vibration damper wherein the elastic elements are subjected only to pressure loads or, if adhesion has been used in construction, to pressure and tensile loads.

The vibration occurring in the drive systems of motor vehicles results on the one hand from the pulsating driving-torque generation and on the other hand from the irregular rolling movement of the wheels on the roadway. Furthermore, mass accelerations occurring transversely of the axis of the drive and its universal-joint shaft lead to radial vibrations which, aided by the largely elastic suspension and mounting of the entire drive -system, take effect partially in the universal-joint shaft as bending vibration. For these reasons alone, a mere torsional vibration damper cannot be used.Moreover, in the suppressor according to German Patent Specification No. 710,556 there is the. difficulty that because of the applied pretensioning the elastic elements harden to such an extent that in consequence of the high resistance to deformation vibration-suppressing deflections are hardly still possible.

According to the invention, this problem is solved in that the rubber bodies, which are of prismatic cross-section, are arranged between defining faces of the mounting flange and of the flywheel ring, and abutments for limiting deformation extend on the flywheel ring and/or the mounting flange along a defined gap. A vibration suppressor of this kind may advantageously be so designed that the flywheel ring surrounds the mounting flange, or, for reasons of space, is arranged axially beside it.The prismatic rubber bodies are either introduced under prestress between the two parts to be connected, so that the rubber bodies can be subjected only to a pressure load, or they are preferably vulcanised or cemented onto the defining faces of the mounting flange and the corresponding defining faces of the flywheel ring, so that they can be subjected both to a pressure load and to a tensile load. During turning movements of the flywheel mass occurring in operation with respect to the hub, the rubber bodies bulge very slightly outwards. On reaching a limit deformation, the rubber bodies bear against the flywheel mass and the natural frequehcy of the suppressor changes in such manner that the amplitudes become smaller and the system is therefore detuned in itself.The invention counteracts this detuning and in fact advantageously in that uniformly distributed chambers are worked into the inner circumferential surface of the flywheel ring. The mounting flange is preferably provided with arms pointing radially outwards and the number of which is identical with the number of chambers in the flywheel ring. The arms of the mounting flange extend at least partially into the corresponding chambers. Due to the radial length of the arms and the resultant defined gap between the radial end of the arms and the head of the chamber, the vibration behaviour of the suppressor can be advantageously so influenced that these suppressors can be adapted to the appropriate case of application. Preferably, the axial length of the chambers in the flywheel ring corresponds substantially to the axial width of the rubber bodies.This is to be regarded as advantageous in the case of vibration suppressors whose flywheel mass must be arranged axially beside the hub for reasons of space without the vibration behaviour of the suppressor changing.

Depending on the case of application, one end wail of the chambers may naturally also be partially or completely closed. Furthermore, there is the possibility of placing the chambers not in the flywheel mass, but in the hub, and of providing the flywheels mass with arms pointing radially inwards.

The vibration suppressors 1 shown in the drawing comprises a star-shaped mounting flange 2 in the arms of which through holes 4 for fixing it to a universal-joint shaft (not shown) are arranged. The mounting flange 2 is surrounded in the radial direction by a flywheel ring 5 into whose inner circumferential surface 6 uniformly distributed chambers 7 are worked. The arms 3 of the mounting flange 2 project partially into the corresponding chambers 7. On both sides, as seen in the circumferential direction, rubber bodies 8 in the form of prisms are arranged and are vulcanised onto the defining faces 9 of the arms 3 of the mounting flange 2 and the defining faces 10 of the chambers 7 of the flywheel ring 5.

Between the rubber bodies 8, the radial ends of the arms 3 of the mounting flange 2 and the heads 11 of the chambers there extends in the circumferential direction a defined gap 12 along or across which limitation of the deformation of the rubber bodies 8 in the radial direction is produced against the chamber head 11 when there is a heavy pressure load and a resultant bulging outwards of the rubber bodies 8.

Claims

1. A vibration suppressor for reducing torsional and/or bending vibrations in a rotating shaft comprising a mounting flange for attachment to the shaft, the mounting flange having a plurality of arms which extend radially outwards from the shaft when the mounting flange is mounted on the shaft, and a flywheel ring connected to the arms of the mounting flange by intervening rubber bodies wherein the rubber bodies extend between defining faces of the mounting flange and the flywheel ring and abutments for limiting deformation of the rubber bodies are formed on the flywheel ring and/or the mounting flange and are spaced from the rubber bodies by a predetermined gap in the rest condition.

2. A vibration suppressor as claimed in claim 1 in which the defining faces of the flywheel ring and mounting flange lie in generally radial planes.

3. A vibration suppressor as claimed in claim 2 in which the abutment surfaces extend circumferentially and lie radially outwards of the rubber bodies.

4. A vibration suppressor as claimed in any of ciaims 1 to 3 in which the inner circumferential surface of the flywheel ring is formed with uniformly distributed chambers into which the arms of the mounting flange extend.

5. A vibration suppressor as claimed in claim 4 in which the rubber bodies rest under pre-stress between the arms of the mounting flange and the circumferentially spaced defining surfaces of the chamber.

6. A vibration suppressor as claimed in claim 4 or 5 in which the axial length of the chambers corresponds to the axial width of the rubber bodies.

7. A vibration suppressor as claimed in any of the preceding claims in which the rubber bodies are vulcanized or cemented onto the defining faces of the flywheel ring and of the arms of the mounting flange.

8. A vibration suppressor for a propeller shaft of a motor vehicle substantially as described with reference to the accompanying drawing.