GB2501286A

GB2501286A - Torsional vibration damper having a plurality of chambers containing a liquid and a gas

Info

Publication number: GB2501286A
Application number: GB1206821.9A
Authority: GB
Inventors: Matthieu Hiard; Bertrand Eber
Original assignee: GM Global Technology Operations LLC
Current assignee: GM Global Technology Operations LLC
Priority date: 2012-04-18
Filing date: 2012-04-18
Publication date: 2013-10-23
Also published as: GB201206821D0

Abstract

A torsional vibration damper 1 (10, fig 2) for damping torsional vibrations is provided that comÂprises a housing 8 comprising a preferably annular inner wall 3, a preferably annular outer wall 2 and a plurality of dividing walls 4 extending between the inner wall 3 and the outer wall 2 and define a plurality of chambers 5 for receiving a liquid and a gas. The chambers 5 may have connecting passages (11, fig 2). A cover is preferably provided for the damper. The damper may have mounting members 9. The damper is preferably used in a vehicle transmission, preferably an automatic transmission, and may be mounted on a dual mass flywheel and/or a torque converter.

Description

Torsional vibration damper for a vehicle transmission and a vehicle transmission The present invention relates to a torsional vibration damper for a vehicle transmission and a vehicle transmission including at least one torsional vibration damper. The torsional vibra-tion damper may be used for damping torsional vibrations of a crankshaft of an engine for a vehicle, for example.

Torsional vibration dampers may be used for damping torsional vibrations of a shaft. For example, in a vehicle driven by a reciprocating engine, the crankshaft of a reciprocating engine may torsionally vibrate. These torsional vibrations may be transmitted to the trans-mission and cause undesirable rattles and booming. A torsional vibration damper may comprise a housing, which may be connected to the crankshaft, and have a closed annular reception chamber for receiving a fluid, such as a silicone oil, having high viscosity.

US 2009/0255368 discloses an arrangement in which the flywheel ring and the high viscosi- ty fluid are arranged in an annular reception chamber and the flywheel ring is circumferen- tially mounted on a supporting ring which is connected to the housing. Such an arrange-ment aims to result in the damping behaviour of the torsional vibration damper being largely independent of the respective excitation frequency and also of the respective operating temperature.

However, further improvements to the damping behaviour of torsional vibration dampers are desirable.

A torsional vibration damper for damping torsional vibrations is provided that comprises a housing comprising an inner wall, and outer wall and a plurality of dividing walls. The divid- ing walls extend between the inner wall and the outer wall and define a plurality of cham-bers for receiving a liquid and gas.

The torsional vibration damper is a separate discrete component which may be used to damping torsional vibrations, for example torsional vibrations of a crankshaft of an engine for a vehicle. In use, the torsional vibration damper may be mounted on various compo-nents of a vehicle transmission, such as a torque converter or a flywheel to damp torsional vibrations. The liquid and gas are enclosed within the chambers and the liquid is able to move within the chamber due to the gas and is able to oscillate with a phase opposing that of the torsional vibration and thus damp the torsional vibrations. In contrast to tuned toN sional vibration dampers, the torsional vibration damper is not designed to damp only a specific frequency, but is able to damp torsional vibrations over a frequency range.

In one embodiment, the torsional vibration damper is annular. Therefore, the inner wall and outer wall are annular and the dividing walls extend radially to provide the plurality of cham-bers. An annular design is suitable for mounting on a shaft and also provides a uniform damping structure around the shaft. The diameter of the inner wall and the diameter of the outer wall may be selected in order to adjust the system inertia.

The torsional vibration damper may further comprise a cover for sealingly closing the chambers. The cover may be used to prevent leakage of liquid positioned within the cham-bers.

In some embodiments, the chambers are formed as recesses in a surface of a member such that the bases of the chambers, the inner wall, the outer wall and the dividing walls are provided by remaining portions of the member.

In some embodiments, a surface of the component onto which the torsional vibration damper is mounted may be used to sealingly close the chambers.

One or more of the chambers may be partially filled with a liquid such as oil. This liquid may have a predetermined viscosity which may be adjusted in order that the particular frequency range of vibration which occur in a particular system may be damped. The remaining vol-ume of the chambers which is not filled with liquid is filled with gas, for example air. This enables the liquid to move within the chambers and provide a damping effect.

In some embodiments, at least one chamber is in flow communication with a neighbouring chamber. This may be achieved by providing one or more channels extending between neighbouring chambers, for example, through the dividing walls. Movement of the liquid within the channels may also provide a damping effect.

The channel shape may be selected to increase the pendulum effect of the damper. Oil within the channel can have a longer travel when subjected to torsional excitation. The number, volume and shape of the chambers as well as the liquid fill level, the liquid type and the viscosity of the liquid may be adjusted in order to adjust the overall damping effect as well as the damping effect at particular frequencies.

The torsional vibration damper may further comprise at least one mounting member. The mounting member may be a protruding pin and/or a through hole, and/or a screw and/or a bolt. If two or more mounting members are provided, they may be arranged equidistantly around the housing in order to enable the torsional vibration damper to be reliably mounted on a rotatable component of a vehicle transmission and to minimize the imbalance induced by the torsional vibration damper.

A vehicle transmission is also provided, which comprises a shaft having a first end config-ured to be coupled to, and driven by, an engine. The engine may be a reciprocating engine which drives a crankshaft. The vehicle transmission comprises at least one torsional vibra- tion damper according to one of the embodiments described above. As previously dEs-cussed, the torsional vibration damper may be mounted on different components within the transmission. If two or more torsional vibration dampers are provided, they may be the same or they may differ in the construction and/or in the liquid provided in the chambers in order to provide differing damping effects at different positions in the transmission. This enables the damping characteristics of each of the torsional vibration dampers to be adjust-ed depending on the torsional vibrations occurring in a particular part of the transmission.

In one embodiment, the vehicle transmission comprises a dual mass flywheel and the tor-sional vibration damper is mounted on the dual mass flywheel. If a dual mass flywheel is provided, it comprises a primary flywheel on the engine side and a secondary flywheel on the transmission side. The torsional vibration damper may be mounted on the secondary flywheel.

In further embodiment, the vehicle transmission comprises a torque converter and the tor-sional vibration damper is mounted within the torque converter.

The vehicle transmission may be an automatic transition. However, a torsional vibration damper, according to the embodiments described above may also be used in a manual transmission.

A vehicle is also provided comprising the vehicle transmission according to one of the pre-viously described embodiments in which the vehicle transmission is coupled and decoupled to the engine and, in particular, to the crankshaft of an engine via a torque converter or a clutch. The torsional vibration damper may be mounted within the vehicle transmission to damp torsional vibrations of crankshaft and assist in isolating the transmission from torsion-al vibrations caused by the engine.

In an automatic transmission including a torque converter, one option to reduce the fuel consumption is to close the torque converter when the crankshaft is rotating at a few revolu- tions per minute (rpm). However, at lower rpm, for example from idle to 1500 rpm, the en-gine typically exhibits the maximum irregularities causing torsional vibrations. The torsional vibration damper may be effective in this low RPM range to damp torsional vibrations and prevent phenomena such as rattle, growling and booming, which are undesirable to the driver and occupants of the vehicle.

Embodiments will now be described with reference to the accompanying drawings.

Figure 1 illustrates a torsional vibration damper according to a first embodiment, Figure 2 illustrates a torsional vibration damper according to a second embodiment, Figure 3 illustrates a schematic diagram of a vehicle transmission including a torsional vi-bration damper, Figure 4 illustrates a schematic diagram of vehicle transmission, including a torsional vibra-tion damper, Figure 5 illustrates damping characteristics of a torsional vibration damper according to the invention.

Figure 1 illustrates a torsional vibration damper 1 according to a first embodiment. The tor- sional vibration damper 1 has an annular or ring-shaped form and comprises an outer an-nular wall 2 and an inner annular wall 3. The torsional vibration damper 1 further comprises a plurality of dividing walls S which extend radially between the inner annular wall 3 and the outer annular wall 2 and define a plurality of chambers 5.

Each of the chambers 5 has a trapezoidal form and is closed at its baseS. Each of the chambers 5 may be considered to be a recess positioned in a surface 7 of a ring-shaped memberS providing a housing. The recesses are open at the surface 7 of the ring-shaped member S. The torsional vibration damper 1 further comprises a plurality of mounting mem-bers 9 positioned equidistantly around surface 7 of the torsional vibration damper 1. The mounting members 9 are positioned in, or protrude from, the dividing walls 4 and are posi-tioned between chambers 5. The mounting members 9 may comprise a pin, screw or a bolt which enables the torsional vibration damper ito be mounted onto a component of a vehi-S cle transmission.

In use, the chambers 5 are partially filled with a liquid, for example, oil having a predefined viscosity. The remainder of the volume of the chambers 5 is filled with gas, such as air The liquid is able to move within the chambers S as each of the chambers 5 is only partially filled with the oil. This movement of the oil reacts in the opposing manner to torsional vibrations of the component on which the torsional vibration damper 1 is mounted. The vibration of the oil within the chambers 5 may have the opposite phase to that of the vibrations of the com- ponent and provide a damping effect due to the opposing phase. Since the torsional vibra- tion damper 1 reacts to the vibrations of the component, it can be said to be tuned. Howev-er, the torsional vibration damper 1 is able to provide a damping effect over a frequency range, rather than being changed to tuned to damp only a single particular frequency.

Figure 2 illustrates a torsional vibration damper 10 according to a second embodiment.

Components of the torsional vibration damper 10, which are the same as that of the first embodiment, are indicated with the same reference number and are not necessarily de-scribed again.

The torsional vibration damper 10 comprises a plurality of chambers 5 which are defined by an outer annular wall 2, an inner annular wall 3 and radially extending dividing walls 4 as in the first embodiment. In the second embodiment, the torsional vibration damper 10 further includes a channelsi 1, which extends through the dividing wall 4 so that neighbouring chambers 5 are in flow communication with one another. Oil present in the chambers 5 can also flow through the channel 11 between neighbouring chambers 5, providing a further damping effect. Figure 2 illustrates two chambers 5 connected by a channel ii in a single quadrant of the annular torsional vibration damper 10. The further three quadrants also have the same arrangement although this is not illustrated in Figure 2 for clarity.

In some embodiments, all of the chambers are in flow communication with one another. In other embodiments, groups of chambers are provided which are in flow communication with chambers within the group, but not in flow communication with chambers of other groups.

Figure 3 illustrates a schematic diagram of a vehicle manual transmission 20 including a dual mass flywheel 21. The inertia of the engine and the primary wheel of the dual mass flywheel 2lis illustrated with reference number 22. The engine inertia and inertia of the primary flywheel is coupled by a spring to the inertia of the secondary flywheel 23 of the dual mass flywheel 21, such that vibrations may be transferred and damped from the en- gine to the secondary flywheel 23. The secondary flywheel 23 is coupled to the transmis- sion 24 by means of a clutch 25. The torsional vibration damper 26 is mounted on the sec-ondary flywheel 23.

Figure 4 illustrates a vehicle automatic transmission 30 including a torque converter 31. The torque converter 31 comprises a turbine accommodated within a housing, which is con- nected to flywheel, which is in turn connected to the engine. The engine inertia is repre-sented by the reference number 32 and is coupled to the turbine inertia 33 by a clutch when the torque convener is in lock mode or by viscous coupling when the torque converter is in free mode. Turbine inertia is coupled to the transmission inertia 34 by a spring. The torsion- al vibration damper 35 is mounted within the torque converter, so that it can damp vibra-tions arising from the engine 32.

Figure 5 illustrates a graph of amplitude of vibration against time. The solid line schemati-cally illustrates torsional vibrations arising from the engine and the dashed line illustrates the vibration of the od within the torsional vibration damper. The phase of the vibration of the oil within the torsional vibration damper opposes that of the engine vibrations and thus provides a damping effect.

While at least one exemplary embodiment has been presented in the foregoing summary and detailed description, it should be appreciated that a vast number of variations exist. It should also be appreciated that the exemplary embodiment or exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration in any way. Rather, the foregoing summary and detailed description will provide those skilled in the art with a convenient roadmap for implementing at least one exemplary embodiment, it being understood that various changes may be made in the function and arrangement of elements described in an exemplary embodiment, without departing from the scope as set forth in the appended claims and their legal equivalents.

Claims

Claims 1. A torsional vibration damper (1; 10) for damping torsional vibrations, the torsional vibra-tion damper (1; 10) comprising: a housing (8) comprising an inner wall (3), an outer wall (2) and a plurality of dividing walls (4), the dividing walls (4) extending between the inner wall (3) and the outer wall (2) and defining a plurality of chambers (5) for receiv-ing liquid and gas.
2. The torsional vibration damper (1; 10) according to claim 1, wherein the torsional vibration damper (1; 10) is annular.
3. The torsional vibration damper (1:10) according to claim 1 or claim 2, further compris-ing a cover for sealingly closing the chambers (5).
4. The torsional vibration damper (1; 10) according to one of claims ito 3, wherein at least one chamber (5) is partially filled with a liquid.
5. The torsional vibration damper (1; 10) according to claim 4, wherein the liquid is oil having a predetermined viscosity.
6. The torsional vibration damper (1; 10) according to one of claims ito 5, wherein at least one chamber (5) is in flow communication with a neighbouring chamber.
7. The torsional vibration damper (1; 10) according to one of claims ito 6, further corn- prising channels (ii) extending through the dividing walls (4) to provide flow communi-cation between two adjacent chambers (5).
8. The torsional vibration damper (1; 10) according to one of claims 1 to 7, further com-prising at least one mounting member (9).
9. The torsional vibration damper (1; 10) according to one of claims ito 8, further com-prising a plurality of mounting members (9) arranged equidistantly around the housing (8).
10. A vehicle transmission, comprising: a shaft having a first end configured to be coupled to an engine, and at least one torsional vibration damper (1; 10) according to one of claims ito 9.
11. The vehicle transmission according to claim 10, further comprising a dual mass fly- wheel, wherein the torsional vibration damper (1; 10) is mounted on the dual mass fly-wheel.
12. The vehicle transmission according to claim 10 or claim 11, further comprising a torque converter, wherein the torsional vibration damper (1; 10) is mounted within the torque converter.
13. The vehicle transmission according to one of claims 10 to 12, wherein the vehicle transmission is an automatic transmission.
14. A vehicle comprising the vehicle transmission according to one of claims 10 to 13.