WO2000046524A1 - Device for damping oscillations, notably oscillation damper - Google Patents

Abstract

The invention relates to a device for damping the oscillations of a rotating component. Said device comprises a primary mass which can be at least indirectly coupled to the rotating component, and a secondary mass. The two masses can be rotated in relation to each other to a limited degree in the peripheral direction. The device also comprises at least one anti-friction bearing (7) for absorbing axial forces. According to the invention such a device is characterized in that a device (10) is provided for which subjects the anti-friction bearing to a force so as to press the anti-friction rolling elements against the race of at least one of the bearing rings (7.1, 7.2).

Description

 Device for damping vibrations, in particular vibration absorbers

The invention relates to a device for damping vibrations of a rotating component, in particular a vibration damper, in detail with the features from the preamble of claim 1.

The expression "device for damping vibrations" is to be understood in the broadest sense. These can be so-called vibration absorbers, vibration damping devices or combined devices between vibration absorbers and vibration dampers. A vibration damper is understood to mean a device which reduces the vibrations occurring in the drive train, in particular on rotating components, and not the damping of vibrations during the torque transmission between two components in the

Powertrain is used. A damper is therefore not primarily involved in the torque transmission during the entire operation from an input to an output side. A vibration damping device is generally an elastic coupling that is arranged between two components, for example an internal combustion engine and a transmission. Couplings of this type are used to prevent torsional vibrations from the rotor from being transmitted to the rest of the drive train. Such an elastic coupling is disclosed in DE-PS 28 48 748. A combined vibration damper damping device is described in the application DE 197 28 894. The one between the two

Elements - primary mass and secondary mass - provided spring devices serve to carry the secondary mass during the start-up phase and the acceleration phases. Otherwise there is essentially no torque transmission.

CONFIRMATION COPY Devices for damping vibrations are designed in such a way that the critical speed of the entire mass system is sufficiently far below the operating range. When driving through the critical speed, there should be no large amplitudes and no large torsional moments in the individual elements.

Essential elements of a vibration damper or a damper are a damping device and a spring device. The damping device comprises chambers which are in conductive connection with one another via channels of defined width. It is during the

Operation displaces a damping agent from one chamber through the channel into the adjacent chamber. The spring device comprises a plurality of springs which are arranged on a circle which is coaxial with the damper or damper axis.

Such a device is generally equipped with roller bearings. One flywheel is often mounted on the other. For this purpose, a single bearing can be used - see DE 28 48 784 C3, or two roller bearings lying next to each other are provided - see DE 34 12 961 A1. It is also possible to mount one flywheel on the drive shaft by means of a first bearing and the other by means of a further bearing on the first flywheel.

In practice, all of these bearings are subject to high forces. These are primarily radial forces. These are by no means constant. Axial loading generally only takes place to a very small extent or not at all.

The bearings represent a weak point of the devices mentioned. They have a life that can be extremely short. If such a bearing fails, the entire bearing must be replaced for the purpose of replacing the bearing Device disassembled and reassembled, which is a high cost and thus causes high costs.

The invention has for its object to design a device according to the preamble of claim 1 such that a longer life of the bearing is achieved.

This object is solved by the features of claim 1. The inventors have recognized the following: Because of the special conditions in a device of the type mentioned, the rolling elements, for example the bearing balls, do not circulate at all. The rolling elements are therefore almost or almost stationary during the entire operation. However, the bearing carries out vibrations that run in the axial direction. This leads to wear that could be called vibration friction wear.

By applying an axial force according to the invention to one of the bearing rings, the rolling elements are also acted upon axially. The individual rolling element is constantly pressed against the running surface of the bearing ring in question. This causes the rolling elements to roll.

The standstill of the rolling elements is thus eliminated and thus also the frictional wear, which is essentially concentrated on individual points or lines.

Generating such axial forces on the rolling elements through the action of magnets represents a very elegant and structurally simple one

Solution.

In practice, this can be moved in that a certain component, for example one of the flywheels, is axially acted upon by magnetic force and presses with a collar against one of the bearing rings, so that this too, and thus the rolling elements, are displaced in the axial direction.

The invention can be applied to any type of bearing that can absorb axial as well as radial forces. In general, the bearings in question are designed primarily to absorb radial forces. To a certain extent, however, they must also be able to absorb axial forces. There are therefore essentially ball bearings, angular contact ball bearings and tapered roller bearings or other axially loadable roller bearings, the latter also called "shoulder bearings".

The invention is explained by way of example with reference to the drawings. The following is shown in detail:

Figure 1 shows a vibration damper in an axial section.

Figure 2 shows the subject of Figure 1 in an enlarged view.

Figure 3 shows the subject of Figure 1 in a view in

Axis direction.

The device shown in Fig. 1 is located on a rotating component. In this case, the device is not involved in the torque transmission. The device is connected via the shaft journal 1 to the rotating component, which is not shown in detail here. This is rotatably connected to a center plate 2. A flywheel 3 is rotatably mounted on the shaft journal 1. With the flywheel 3 side windows 4, 5 are rotatably connected.

The flywheel 3 is mounted on the shaft journal 1 by means of a needle bearing 6 and a ball bearing 7. The needle bearing 6 can only absorb radial forces, the ball bearing 7, however, also axial forces. The primary mass of the device comprises the shaft journal 1 and the center disk 2. The secondary mass comprises the flywheel 3 and the side disks 4, 5. The two masses can be rotated relative to one another to a limited extent in the circumferential direction. As can be seen from Figure 3, a plurality of spring devices 8 are provided, of which only the holder 8.1 are shown, further displacement chambers 9, which are filled with a pasty agent, and in which this means in a known manner in the limited rotation mentioned by narrow gaps is squeezed so that a torsional resistance is applied.

According to the invention, a plurality of permanent magnets 10 are embedded in one of the two side windows, namely in the side window 4. As can be seen from FIG. 3, these are distributed over the side window 4 at the same mutual angular intervals on one and the same radius. It would also be conceivable to arrange the magnets 10 on different radii in the side window 4. It should be ensured that the side window is not deflected from its perpendicular position by the magnetic forces.

As you can see, there are five magnets 10 in the present case. However, more or fewer magnets could also be provided.

In theory, a ring magnet is ideal. Its axis then coincides with the axis of rotation of the vibration absorber / damper. The division of the ring magnet into individual magnets makes more economic sense. Theoretically, two such magnets would then suffice. Appropriately, however, there should be at least three magnets.

Electromagnets could also be used instead of permanent magnets. This would have the advantage of being able to regulate.

The magnets 10 are designed and arranged with respect to their poles in such a way that they pull the center disk 2 towards the side disk 4. The Outer ring 7.2 of the bearing 7 is supported in the flywheel 3. It is advantageous to fix this outer ring without play. The inner ring 7.1 of the bearing 7 is in turn fixed over the bearing pot 2.2 and the collar 2.1. It is thus fixed relative to the center disk 2 and the shaft journal 1. The clearance-free setting is also advantageous for the inner ring.

An axial force is generated between the components 4 and 3, thus ultimately the outer ring 7.2, and the components 2, 2.1, 2.2 and 1, and thus ultimately the inner ring 7.1, via the magnets 10. According to the invention, this axial force causes the remaining bearing play between the inner bearing ring, rolling elements and outer bearing ring to be canceled. Due to the axial force

Rolling elements pressed between the bearing inner and outer rings, which move axially relative to one another, against the respective running surfaces. If the bearing inner ring 7.1 and / or the bearing outer ring 7.2 are not yet fixed free of play in their bearing seats, this axial force can additionally cause the axial play of the inner and outer ring to be canceled in their respective bearing seats in the shaft and hub area. Advantageously, however, inner ring 7.1 and outer ring 7.2 are already fixed without axial play. This causes the balls to circulate, thereby avoiding the aforementioned vibratory friction wear.

The invention achieves a considerable increase in the life of the bearings of a few tens of thousands of hours.

Claims

claims 1. Device for vibration damping of a rotating component; 1.1 with a primary mass which can be coupled at least indirectly to the rotating component; 1.2 with a secondary mass; 1.3 the two masses can be rotated relative to one another to a limited extent in the circumferential direction; 1.4 at least one roller bearing (7) is provided for absorbing axial forces; characterized by the following features: 1.5 a magnetic device (10) is provided with which the roller bearing (7) is acted upon in order to press the roller bodies against the running surface of at least one of the bearing rings (7.1, 7.2). 2. Device according to claim 1, characterized by the following features: 2.1 one of the two masses has a central disc (2); 2.2 the other of the two masses has two side disks (4, 5) which sandwich the middle disk between them; 2.3 one (4) of the two side windows (4, 5) are assigned magnets (10). 3. Device according to one of claims 1 to 2, characterized in that the magnets are permanent magnets. 4. Device according to one of claims 1 to 2, characterized in that the magnets are electromagnets. Apparatus according to claim 4, characterized in that the electromagnets are adjustable for setting certain bearing preload forces.