DE102008015742A1 - Clutch, has intermediate wheel arranged between guidance device and housing for transferring torque, and mechanism for producing and/or varying magnetic fields changing viscosity of magnetorheological liquid - Google Patents

Abstract

The clutch (1) has an intermediate wheel (4) i.e. intermediate disk, arranged between a guidance device (2) and a housing (3) for transferring a torque. The wheel is connected with a shaft in a force-fit and/or form-fit manner, on the housing, where the wheel is adjusted to a form closure with the housing. A magnetorheological liquid (MRF) changeable in its viscosity is provided in a gap (18) between the wheel and the housing for transferring the torque. A mechanism is provided for producing and/or varying magnetic fields changing the viscosity of the MRF. An independent claim is also included for a method for switching a clutch.

Description

Field of the invention

The Invention relates to a coupling with a guide device, a housing and an interposed intermediate wheel for transmitting a torque from the idler, the positively and / or positively connected with a shaft is on the housing, with the idler gear in a positive connection is displaceable with the housing.

The The invention also relates to a method for switching such Clutch.

Couplings of various types are already known from the prior art. For example, US patent application US 2006/0049018 A1 discloses a clutch designed with a plurality of disks and a method for synchronizing the individual torque transmission elements. The US 2006/0049018 A1 discloses a shaft which provides an input torque. A piston housing is further connected to the shaft and houses a piston. The piston is slidably mounted on the shaft and is in positive engagement with the shaft via a toothing.

Of the Piston is replaced by hydraulic oil passing through the piston housing is supplied, moved away from the piston housing. there gets a toothing of the piston in contact with an external toothing a friction disk.

These Friction disc also has an internal toothing, which in operative engagement is located with the external teeth of the shaft. The friction disk is then pushed by means of the piston on an intermediate. by virtue of the now arising between the friction disc and the intermediate Friction, the idler gear is at the speed applied to the piston accelerated. Only at this time is a positive connection of moving on Piston on the internal teeth to an external toothing of the intermediate wheel.

These and similar types of couplings, which are also several lamellae and viscous couplings and electromotive couplings, have the disadvantage that they require a lot of axial space. For each individual gear, namely to guarantee a synchronization, such a considerable amount of space is available to deliver. Furthermore, those known from the prior art Clutches have the disadvantage of causing high overall system costs, subject to high wear due to solid friction and, in particular viscous couplings, high idling torques at high speed have to accept.

From the prior art, couplings are known that use magnetorheological fluids. Such couplings are about from the DE 21 2004 000 042 U1 , of the DE 20 2006 010 663 U1 and the DE 11 2005 000 727 T5 known.

Indeed have the known from the prior art couplings, which use magnetorheological fluids, the disadvantage that only limited high torques are transferable. One Use in high-torque diesel engines prohibits such Coupling types.

Furthermore, the DE 20 2006 010 663 U1 the disadvantage that large amounts of relatively expensive magnetorheological fluid are needed.

It the object of the present invention is an improvement here to make available so that a clutch is achieved is needed, which requires only a small space, the necessary Switching times are reduced while the cost of the entire system reduced. The idling torques should also be kept small.

In This application will be hereinafter magnetorheological fluids also abbreviated to "MRF". Such magnetorheological Liquids (MRF) represent an alternative to electrorheological Liquids. This also known as "ERF" Liquids, however, are within the scope of this invention used in place of magnetorheological fluids.

Disclosure of the invention

The The object shown above is by a generic Clutch solved by one in their viscosity changeable magnetorheological fluid in one located between the idler and the housing Space for transmitting a torque available is and means for generating and / or varying a Viscosity of the magnetorheological fluid (MRF) has changing magnetic field.

Characterized in that a magnetorheological fluid is present in the gap, when activated by means of a magnetic field, the viscosity of the magnetorheological fluid increase, which means that the movement of the shaft via the intermediate wheel by means of the high-viscosity liquid is transferable to the housing. The housing is thereby accelerated. Due to the fact that the intermediate wheel is slidable in the direction of the housing, with appropriate sliding of the intermediate wheel in the direction of the housing, on the then highly viscous MRF transmit torque even more to the case. Even very high torques and forces are transferable when the intermediate gear enters into positive engagement with the housing, even if the magnetic field fails or is switched off for energy saving reasons. A power-saving and fail-safe coupling is the result.

The The object of the invention is also achieved by a method for switching solved a clutch in which the intermediate at elevated Viscosity of the MRF in the direction of a positive locking device of the housing is moved and only at reduced again Viscosity of the MRF the idler gear in positive connection with the Housing is brought.

By Such a procedure is in addition to the already The coupling described advantages also a wear-free Engaging allows, as a fitting of the formschlussermöglichenden Elements of the idler and the housing at again reduced viscosity is easier, which lowers the wear of these elements. As such Elements are advantageously projections and recesses, as they are present in gears, usable.

advantageous Embodiments of the coupling are in the dependent claims claimed and in the following embodiments explained in more detail.

So It is particularly advantageous if the intermediate wheel slidably over a toothing is connected to the shaft. In this way it is ensured that in each shift position the same thing Transferring torque from the shaft to the idler gear is rotated, ie with the same number of revolutions as the shaft. Even when moving the idler, always the same power transmission remains available.

A particularly simple and efficient adjustment of the intermediate wheel, is then enabled when the guiding device a sleeve having a Schaltgabelangriffsbereich and the sleeve form fit over a Gearing is stored on the while. By a form-fitting Store the sleeve on the shaft by means of a toothing It is also ensured that the guide device with the same number of revolutions as the shaft and the idler wheel. Unnecessary wear between these three elements is avoided. The clutch will be even more durable. It is particularly advantageous if the guide device, the sleeve and the intermediate are formed integrally. However, a multi-part design is possible and facilitates the assembly in special cases.

If the shift fork attack area is formed as a recess, in which preferably interlocks a shift fork, so can rely on existing displacement means for the idler which reduces the testing effort and the reliability further increased.

In a further advantageous embodiment, it has turned out to be positive when arranged a solenoid so is that when energizing the coil, an increase in viscosity the magnetorheological fluid occurs. So is by one corresponding arrangement of the solenoid the viscosity the magnetorheological fluid can be changed in a timely manner, so that precise shifting is possible.

If in the intermediate wheel, which is preferably designed as an intermediate disc is, passages are included, which pass through the magnetorheological fluid through the intermediate wheel allow, so there is another advantage. This The advantage is that pressures in the intermediate range of Guide device and housing are compensated and when pushing the intermediate wheel in the direction of the guide device facing away from the housing, no unnecessary resistance due to the expected compression of the MRF. The precision the clutch when shifting is increased. Also does not have to so much heat is dissipated, which in turn the Lifespan increased.

When has proven particularly efficient, if in one embodiment at the outer edge of an external gear having intermediate in operative engagement with an internal toothing of the housing slidable. Particularly high torques can be transferred in this way. Also, the corresponding can be Manufacture external and internal gears with high precision, whereby the switching accuracy is increased.

Leakage losses can then be permanently and effectively avoided if a seal against an exit of the MRF in the form of a permanent magnet seal is attached to a transition region between the housing and the guide device. The permanent magnet seal increases the viscosity of the MRF in the transition region, ie a sealing region that occurs in the gap between the housing and the guide device, such that it can no longer pass through this gap. The use of a permanent magnet, especially at this point, reduces wear, since no longer usual mechanical seals must be used. Also, such a seal does not require a permanent or intermittent energy supply. a great freedom from maintenance is guaranteed.

If the transition region on the side facing the shaft is arranged of the idler, so do not occur high centripetal forces the magnetorheological fluid on, thereby reducing the burden the seal is reduced. The probability of leaving Fluid from the clutch is reduced, resulting in operating costs reduced such a coupling.

In order to also appropriate support forces can be applied, without causing unnecessary wear it is advantageous if in a further embodiment in the transition region a sliding or rolling bearing is arranged. As such camp offers a radial needle bearing because this requires only small space requirements. Indeed Other bearings such as barrel and / or taper bearings are also usable.

Short description of the drawing

The Invention will be explained in more detail by means of a drawing, the individual figures show the following:

1 A first embodiment of a coupling according to the invention in a schematic sectional view without a shaft,

2 a second embodiment of a coupling according to the invention, wherein the shaft is not shown and the coupling is shown schematically in section,

3 a partially sectioned perspective view in a schematic manner by a guide device according to the invention, which has a sleeve and a Schaltgabelangriffsbereich in addition to an intermediate wheel integrally formed and

4 a schematically illustrated perspective view of a partial section through the housing, which has an internal toothing.

embodiments

The Illustrated embodiments serve only as an example the realization of the present invention, its scope or use.

1 shows a first embodiment of a coupling according to the invention 1 , The coupling 1 has a guide device 2 on. Relative to the guide device 2 is a housing 3 movable. The housing 3 and the guide device 2 rotate about the same axis of symmetry, which is not shown.

Between the guide device 2 and the housing 3 is an idler 4 arranged. The intermediate wheel 4 is here formable as a disk and is then referred to as a washer. In the 1 and 2 the idler is designed as an intermediate disc.

In the gap, between the guide device 2 and the housing 3 So also in the area where the idler 4 is located, a magnetorheological fluid MRF is included.

In the present embodiment, the guide device comprises 2 also the intermediate wheel 4 such that these two machine elements are integrally formed. However, the guide device is also designed in several parts, so that they in the intermediate 4 , a sleeve 6 and a shift fork attack area 7 decays.

The shift fork attack area 7 has a recess 8th on, in which a shift fork engages. This shift fork is not shown, but known from the prior art in different embodiments.

Im in 1 illustrated embodiment, the guide device 2 So also the idler 4 , an internal toothing, with the reference numeral 9 is marked. About this internal toothing 9 is a torque from the shaft, not shown, to the intermediate 4 transfer.

The shaft, not shown, which is a torque on the intermediate 4 is usually an input wave. However, the shaft can also be designed as an output shaft, so that then the torque of the intermediate 4 is transmitted to the then acting as an output shaft shaft.

The intermediate wheel 4 has passage openings 10 on. These passages 10 are equidistant to each other in axial alignment relative to a rotation axis of the intermediate gear 4 arranged. The passage openings 10 are sized to provide little resistance to a magnetorheological fluid passing through them. However, a passage of the highly viscous magnetorheological fluid is made correspondingly difficult with a suitable choice of the diameter of the passage openings. The passage openings 10 are designed as holes or through holes. Other channel-like passage openings are possible and do not necessarily have a round cross section, as in 1 shown, have. Also, the through holes 10 each have a different distance from the axis of rotation.

In not yet in form-fitting state of the intermediate wheel 4 regarding the housing 3 , exists between the outer surface of the guide device 2 and an inner surface of the housing 3 a relative speed.

In the transition area between housing 3 and the guide device 2 , which by the reference numeral 11 is provided, a small gap is present, which is sealed by a seal against the exit of MRF. In the embodiments according to 1 and 2 is a schematic as a permanent magnet seal 12 illustrated seal used.

The permanent magnet seal 12 , is an annular permanent magnet formed and arranged to be in the transition region 11 leads to a change in the viscosity of the magnetorheological fluid to the effect that a sealing in the transition region 11 existing gap is reached.

In 1 is a sliding bearing between the housing 3 and the guide device 2 available. This slide bearing is denoted by the reference numeral 13 Mistake.

The intermediate wheel 4 has on its outside an external toothing 14 on. On the intermediate wheel 4 facing side inside the housing 3 is an internal toothing 15 of the housing 3 educated.

The intermediate wheel 4 is by means of the guide device 2 so in the direction of the internal teeth 15 of the housing 3 slidable, that the external toothing 14 of the intermediate wheel 4 in operative engagement with the internal toothing 15 arrives, so produces a positive connection.

The the idler 4 facing side of the internal toothing 15 is roof-shaped provided with tips, so that in a form-fitting of the external teeth 14 with the internal toothing 15 , which serves as a form-fitting device, as frictionless and wear-free.

This in 2 illustrated embodiment differs from the in 1 illustrated embodiment essentially in that the guide device 2 a connector 16 has, which radially from the shaft side facing the guide device 2 protrudes outwards.

In this 2 , as well as in the 3 and 4 , the same reference numerals have been used for the same elements.

In the transition area 11 is unlike the first embodiment, a rolling bearing 17 arranged. The rolling bearing 17 is configured as a radial bearing, in particular as a radial barrel bearing.

In 3 is the one-piece exhibited combination of the guide device 2 comprising the idler gear 4 , the sleeve 6 and the shift fork engagement portion with a recess 8th shown. Both the internal teeth 9 these elements, as well as the external teeth 14 of the intermediate wheel 4 are shown. Here, the cuboid configuration of the individual elements of the external toothing 14 only to be understood schematically. As with the in 4 shown internal teeth, a roof-shaped configuration of the individual teeth is also possible here.

In 4 is the internal toothing 15 in one with the reference numeral 18 provided gap recognizable.

The Operation of the coupling is explained below.

A shift fork engages in the recess 8th the shift fork attack area 7 and pushes both the sleeve 6 , as well as the idler 4 in the direction of the internal teeth 15 of the housing 3 , At the same time, a solenoid, not shown, is activated so that current flows through it and a magnetic field in a gap 18 takes place, so that changes the viscosity of a magnetorheological fluid in this space, also referred to as a gap. By the action of the magnetic field, the viscosity is increased. A movement of the intermediate wheel 4 is as a result on the case 3 transfer. The housing 3 is thereby at the same speed as the idler 4 , ultimately accelerated to the same number of revolutions as the shaft, which is not shown. The intermediate wheel 4 is so long on the internal teeth 15 moved until briefly the external teeth 14 with the internal toothing 15 comes into operative engagement. Then, the solenoid is deactivated again, which lowers the viscosity of the MRF and ultimately the information-guiding movement of the idler wheel 4 with the external teeth 14 in operative engagement with the internal toothing 15 can be done without friction.

The solenoid must therefore be activated only for a short moment, namely until the acceleration of the housing 3 the same number of revolutions as the idler 4 lasts.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• US 2006/0049018 A1 [0003]
• - DE 212004000042 U1 [0007]
• - DE 202006010663 U1 [0007, 0009]
• - DE 112005000727 T5 [0007]

Claims (11)

Clutch ( 1 ) with a guiding device ( 2 ), a housing ( 3 ) and an interposed intermediate wheel ( 4 ) for transmitting a torque from the intermediate wheel ( 4 ), which is non-positively and / or positively connected to a shaft, on the housing ( 3 ), whereby the intermediate wheel ( 4 ) in a positive connection with the housing ( 3 ) is displaceable, characterized in that a variable in its viscosity magnetorheological fluid (MRF) in a between the intermediate ( 4 ) and the housing ( 3 ) intermediate space ( 18 ) for transmitting a torque and having means for generating and / or varying a magnetic field viscosity (MRF) changing magnetic field. Clutch ( 1 ) according to claim 1, wherein the intermediate wheel ( 4 ) is slidably connected via a toothing with the shaft. Clutch ( 1 ) according to claim 1 or 2, wherein the guiding device ( 2 ) a sleeve ( 6 ) with a shift fork attack area ( 7 ) and the sleeve ( 6 ) is mounted positively via a toothing on the shaft. Clutch ( 1 ) according to claim 3, wherein the shift fork attack area ( 7 ) as a recess ( 8th ) is formed, in which a shift fork preferably engages positively. Clutch ( 1 ) according to one of claims 1 to 4, wherein a magnetic coil is arranged so that upon energization of the magnetic coil, an increase in viscosity of the magnetorheological fluid (MRF) occurs. Clutch ( 1 ) according to one of claims 1 to 5, wherein in the intermediate wheel ( 4 ), which is preferably designed as a washer, through holes ( 10 ) passing through the magnetorheological fluid (MRF) through the intermediate wheel ( 4 ) enable. Clutch ( 1 ) according to any one of claims 1 to 6, wherein on the outer edge of an external toothing ( 14 ) intermediate wheel ( 4 ) in operative engagement with an internal toothing ( 16 ) of the housing ( 3 ) is slidable. Clutch ( 1 ) according to one of claims 1 to 7, wherein at a transition region ( 11 ) between the housing ( 3 ) and the guiding device ( 2 ) a seal against a leakage of the magnetorheological fluid (MRF) in the form of a permanent magnet seal ( 12 ) is attached. Clutch ( 1 ) according to claim 8, wherein the transition region ( 11 ) on the side of the intermediate wheel facing the shaft ( 4 ) is arranged. Clutch ( 1 ) according to claim 8 or 9, wherein in the transition region ( 11 ) a sliding or rolling bearing ( 13 . 17 ) is arranged. Method for switching a clutch ( 1 ), characterized in that an intermediate wheel ( 4 ) with increased viscosity of the magnetorheological fluid (MRF) in the direction of a positive locking device of the housing ( 3 ) and only when the viscosity of the magnetorheological fluid (MRF) has decreased again, the intermediate wheel ( 4 ) in positive engagement with the housing ( 3 ) is brought.