GB2162611A

GB2162611A - A rotary vibration damper

Info

Publication number: GB2162611A
Application number: GB08518591A
Authority: GB
Inventors: Hans Gebhardt
Original assignee: MAN Maschinenfabrik Augsburg Nuernberg AG
Current assignee: MAN AG
Priority date: 1984-08-04
Filing date: 1985-07-23
Publication date: 1986-02-05
Also published as: DE3428894A1; GB8518591D0; GB2162611B

Abstract

A rotary vibration damper comprising a primary member (1) mountable on a rotary shaft and a radially-outer secondary member (2) mounted on the primary member (1) by means of a resilient member 3, e.g. of rubber. The secondary member 2 comprises a V-belt pulley unit. In order to allow interchangeability, the secondary member (2) comprises a plurality of parts, i.e. the V-belt pulley unit (5) and a support (4). Optionally the secondary member (2) further comprises an annular mass (6). <IMAGE>

Description

SPECIFICATION A rotary vibration damper This invention relates to a rotary vibration damper.

A torsional vibration damper is disclosed in for example, DE-OS 25 37 390. It consists of a fly wheel-type ring (also called secondary member), a flange (also called primary member) and an intermediate rubber layer. In this arrangement, the primary member is rigidly screwed to a crank shaft and, for compactness, the secondary member is formed as a V-belt pulley (as a single solid part) for driving auxiliary machines (for example a dynamo or a motor-driven water pump). The resilient connection by means of the rubber is free in this damper, i.e. primary and secondary members are joined together non-positively by pressure. The object of the damper is to damp the torsional vibrations of the crank shaft.

To prevent the damper from being actuated in the range of harmless vibrational deflections (unnecessary temperature evolution), the damper is tuned to resonance with the system to be damped.

This is achieved by suitable dimensioning of the secondary member and the rubber mass.

A vibration damper of this type, therefore, begins to operate when resonant speeds occur, the vibratory system being split into a further form of vibration with nodes in the damper by the resilient connection of the secondary member. Harmful resonances can be effectively damped by intentional tuning.

If a spring-mass system tuned and designed for a specific purpose or application is provided with a different moment of inertia, this is usually accompanied by re-determination of the damper.

A further problem resides in the fact that V-belt pulleys of which the effective diameter, belt tracks and belt widths have been altered relative to the original belt pulley make it necessary to re-design the vibration damper.

In other words, the usefulness of a typical damper is based on the following factors: a) Suitability for a specific size of fly wheel (considered from the moment of inertia).

b) suitability for a specific required auxiliary machine V-belt drive.

Compliance with the foregoing points - individually or simultaneously - is synonymous in the current design (the secondary member acting as a Vbelt pulley is formed as a single solid part) with redesign of the damper, i.e. a new damper with primary member and adapted secondary member now have to be connected and attached using the rubber layer. The composition and storage of the damper are correspondingly expensive.

An object of the invention is to provide a rotary vibration damper which is more suitable for the various applications with respect to change of Vbelt pulley unit or with respect to a possible change in the mass of inertia, the conversion and adaptation being achievable in a simple and inexpensive manner. Moreover, the provision and storage of the dampers or of the damper parts should be simplified and this will also reduce costs.

The invention provides a rotary damper as claimed in claim 1.

This division of the secondary member into a plurality of parts according to its function represents a particularly economic solution. The primary member together with the rubber layer and the support may be obtained from a damper manufacturer as one unit in relatively large numbers at a corresponding price. It is necessary to store only this assembly.

Suitable or appropriate V-belt pulley units which are connected in the appropriate manner to the support may be used for the corresponding auxiliary machine drives or for each specific application.

Finally, an additional mass which is connected to the support in the same manner as the V-belt pulley unit can also be provided if necessary. This additional fly wheel-type ring is used if the V-belt pulley unit formed as a solid part does not have sufficient mass or if the damper needs to be used for a mass of inertia which may have been altered.

This additional mass is obviously also used if a Vbelt pulley unit made of sheet metal is used instead of a solid one.

The type of connection of V-belt pulley unit and additional mass to the support may be positive or non-positive (for example as a longitudinal pressure fit or transverse pressure fit) or can be designed as a screw connection.

Embodiments of the invention will now be described with reference to the accompanying drawings, wherein: Figure 1 is a longitudinal section through a first embodiment of a damper.

Figure 2 is a longitudinal section through a second embodiment of a damper.

Figure 3 is a longitudinal section through a third embodiment of a damper.

Figure 4 is a longitudinal section through a fourth embodiment of a damper, and Figure 5 is a longitudinal section through a fifth embodiment of a damper.

In the drawings, a torsional vibration damper comprises a primary member 1 formed as a flange screwed to a crank shaft (not shown), and a secondary member 2 arranged radially outwardly of the primary member 1. A resilient damping layer 3 formed of rubber is provided between the two members 1, 2. There is no physical connection between the rubber layer 3 and the members 1, 2, i.e.

the rubber is only compressed between the members 1, 2.

For compactness in this type of damper, a V-belt pulley unit for driving auxiliary machines is fitted to the secondary member 2. In the past, this was actually formed integrally with the secondary member (fly wheel-type ring).

In accordance with the invention, the secondary member 2 comprises a plurality of parts, i.e. a secondary part support 4, a V-belt pulley unit 5 and an additional mass 6 (additional fly wheel-type ring).

The additional mass 6 is not always necessary, as explained below.

Figure 1 shows a solid V-belt pulley unit 5 which simultaneously acts as a fly wheel-type ring. In Figures 2, 3, 4and 5, a ring 6 is provided in addition to the V-belt pulley unit 5. The additional ring 6 is ,used, for example, if the mass (the moment of inertia) of the V-belt pulley unit selected for the specific application is not sufficient.

The damper will also be adapted to new parameters, for example if the moment of inertia on the fly wheel side is altered, by means of an additional ring. If a V-belt pulley unit made from sheet metal is used (see Figures 4 and 5), the additional ring 6 is invariably required to provide the necessary mo ment of inertia.

The V-belt pulley unit 5 and the additional ring 6 are connected positively or merely by friction to the support 4 forming a unitary assembly with the rubber layer 3 and the primary member 1. The connection may be in the form of e.g. a longitudi nal pressure fit, a transverse pressure fit or a screw connection.

The formation of the secondary member 2 into a number of parts, depending on its function, makes the provision and storage for line assembly and supply of spare parts more economic than in the past. In order to repair "defective dampers" it is necessary to provide only the less expensive as sembly of primary member 1, intermediate rubber layer 3, and support 4. The exchanged parts such as ring mass 6 and V-belt pulley unit 5 can be pressed out and used again.

Claims

1. A rotary vibration damper comprising a pri mary member mountable on a rotary shaft, and a radially-outer secondary member connected to the primary member by means of a resilient damping member, wherein the secondary member is formed of a plurality of parts comprising a support and a V-belt pulley unit.

2. A rotary vibration damper as claimed in claim 1, wherein the support is connected to the primary member by means of the resilient damp ing member.

3. A rotary vibration damper as claimed in claim 1 or 2, wherein the secondary member fur ther comprises an annular mass.

4. A rotary vibration damper as claimed in claim 1, 2 or 3, wherein the V-belt pulley unit or the annular mass is positively or non-positively connected to the support by means of a longitudi nal pressure fit, a transverse fit or a screw connec tion.

5. A rotary vibration damper as claimed in any one of the preceding claims, wherein the V-belt pulley unit is formed from sheet metal.

6. A rotary vibration damper substantially as herein described with reference to any one of the accompanying drawings.

7. A multi-cylinder engine having a crank shaft connected to a rotary vibration damper as claimed in any one of the preceding claims.