DE102011050360A1 - Coupling arrangement for transferring drive torque from drive shaft to auxiliary unit i.e. fan wheel, of motor vehicle i.e. motor car, has liquid frictional clutch attached to disk clutch for torque transmission from drive shaft to output - Google Patents

Abstract

The arrangement has a non-variable liquid frictional clutch (4) attached to a switched friction disk clutch (7) e.g. hydraulic clutch, for torque transmission from a drive shaft (2) to an output (10). The liquid frictional clutch and the switched friction disk clutch are serially arranged such that the flow of power runs from the drive shaft to an auxiliary unit i.e. fan wheel, by the liquid frictional clutch and the friction disk clutch. The liquid friction clutch is arranged between the drive shaft and the friction disk clutch in a torque transmission direction. The switched friction disk clutch is selected from electromagnet clutch, pneumatic clutch, hydraulic clutch, single-stage or multi-stage clutch, or electromagnetically-operated clutch. The liquid friction clutch is formed as a controlled or regulated or self-regulated clutch with bimetal.

Description

The invention relates to a coupling arrangement (coupling device) for transmitting a drive torque to an accessory, in particular to a fan, a motor vehicle, according to the preamble of claim 1, comprising a drive shaft, an output and a switchable friction disc clutch.

Basically known are single or multi-stage friction disc clutches for driving ancillaries, such as fan wheels. Such, for example, designed as electromagnetically actuated clutches friction disc clutches are for example in the EP 0 317 703 A2 , of the DE 32 03 143 C2 as well as the DE 42 07 710 A1 described. With regard to the basic structure, the mode of action and the field of application of such friction disc clutches, reference is made to these publications. Instead of couplings with an electromagnetic switching mechanism pneumatic or hydraulic friction disc clutches are used in the prior art.

Friction disc clutches do not slip when connected and thus do not have a differential speed on the bearing. However, it is well known that this can lead to increased wear and thus to increased wear to the possible failure of the bearings in field use by the lack of rolling of the rolling elements. In particular, in the case of single-stage friction disk clutches, it is disadvantageous that, in the engaged (engaged) state, at high numbers of drives they often provide undesirably high output speeds, and strong shift shocks occur.

Instead of the friction disk clutches described above, so-called fluid friction clutches, also called viscous coupling or viscosity clutch, are used for driving ancillary components of motor vehicles. In the case of viscous couplings, a rotary motion is transmitted from a primary side to a fluid and from there to a secondary side of the clutch.

With regard to a possible construction of fluid friction clutches is on the US 4,305,491 as well as the EP 12 48 007 B1 directed.

Unlike single-stage friction disc clutches, fluid friction clutches have sluggish response and high slip values.

Based on the aforementioned prior art, the present invention seeks to provide an alternative coupling arrangement, which is characterized by a lower wear of the friction disc clutch. In the case of the arrangement of a belt drive on the output of this is preferably less burden. More preferably, the clutch assembly should be characterized by a reduction in energy consumption at high engine speeds and even more preferably have increased damping properties in terms of torsional vibrations and ensure a switching-reduced connection.

This object is achieved with a clutch assembly having the features of patent claim 1, in particular in that the clutch assembly comprises a fluid friction clutch in addition to the friction disc clutch for torque transmission.

Further advantages, features and details of the invention are specified in the subclaims. All combinations of at least two features disclosed in the description, the claims and / or the figures fall within the scope of the invention. In order to avoid repetition, features disclosed in accordance with the device should also be regarded as disclosed according to the method and be able to be claimed. Likewise, according to the method disclosed features should also be considered as disclosed device and claimable.

The invention is based on the idea of combining a single-stage or multi-stage friction disk clutch, preferably designed as an electromagnetic clutch, in a common drive train for an auxiliary unit with a fluid friction clutch. In other words, according to the invention, both a friction disc clutch and a fluid friction clutch are used to transmit a torque from a drive shaft to an accessory of a motor vehicle, in particular to the fan of a motor vehicle radiator. The invention thus consciously takes a more complex and cost-intensive construction of a coupling arrangement at a first glance, in order to then surprisingly combine the advantages of a friction disk clutch known per se and a fluid friction clutch known per se. By combining both technologies in a common clutch assembly, as will be explained in detail later, a muted (smooth) connecting the friction disc clutch can be realized, resulting in less wear of the friction disc clutch, in particular the friction disc of the friction disc clutch. Furthermore, the combination of a friction disc clutch with a fluid friction clutch results in less stress on a belt drive optionally provided on the output. In addition, due to a possible reduction in power consumption can be reduced at high engine speeds. Also, damping of torsional vibrations is achieved due to the combination, whereby the clutch assembly according to the invention is suitable for crankshaft.

Very particularly preferred is an advantageous embodiment of the invention, according to which the fluid friction clutch and the friction disc clutch are arranged in series, ie such that the power flow from the drive shaft to the auxiliary unit passes through both clutches. In other words, the power flow initially passes from the drive shaft in one of the clutches and via this into the other clutch, which then transmits the power from the output. For this purpose, the fluid friction clutch and the friction disc clutch are preferably arranged successively on the drive shaft, wherein it is particularly preferred if the fluid friction clutch is placed in the torque transmission direction between the drive shaft and the friction disc clutch.

It is particularly preferred if the primary side of the fluid friction clutch permanently, d. H. mechanically fixed to the drive shaft is connected, so is automatically always driven as soon as the drive shaft rotates. It is even more preferred when the friction disc clutch is firmly connected to the secondary side of the fluid friction clutch, so that the fluid friction clutch by engaging the friction disc clutch frictionally torque-transmitting connected to the accessory and preferably, especially in the case of the formation of the friction disc clutch as a single-stage clutch by means this is frictionally uncoupled.

Particularly preferred is provided in a further development of the invention that the accessory magnetic means are assigned, in particular in the form of permanent magnets, which are further preferably in the region of the accessory, in particular at the output are arranged in order to entrain the output with the fluid friction clutch vortex current-based in this way , In other words, an inhomogeneous magnetic field is generated by the magnetic means, which induces an eddy current in the counterpart comprising an electrical conductor, in particular in the secondary side of the fluid friction clutch, which in turn generates a magnetic field opposing the magnetic field, which then entrains the magnetic medium. In other words, between the fluid friction clutch and the output preferably an eddy current clutch is realized, which ensures that the output of the fluid friction clutch is entrained. A variant of the clutch arrangement with eddy-current means is particularly advantageous for an embodiment in which the fluid-friction clutch can be decoupled frictionally from the output by means of the friction disc clutch. By providing the magnetic means is achieved that the output permanently, d. H. constantly rotated at an increased speed, creating a basic performance of the accessory, z. B. the fan is reached.

Instead of the arrangement of the magnet means, in particular the permanent magnet on the output, it is of course conceivable to arrange the magnet means on the fluid friction clutch, in particular on its secondary side. It is only essential that a relative rotational movement between the magnetic means on the one hand and an electrical conductor, so either the output or the secondary side of the fluid friction clutch is generated.

It is particularly preferred if the secondary side of the fluid friction clutch carries a return spring of the friction disc clutch. It is particularly useful when it comes to the return spring to a, preferably an anchor comprehensive, friction disc away from the drive towards the secondary side of the fluid friction clutch, d. H. decoupling spring acts, whereby it is of course also possible to form the spring as a compression spring to the friction disc clutch in this case closed in the non-energized state, d. H. to keep engaged.

Particularly useful is a variant in which the fluid friction clutch is a non-variable coupling, d. H. is a trained neither controlled, nor as a controlled clutch clutch, so a clutch in which the height of the slip is not adjustable. In other words, the fluid flow, in particular an oil flow within the fluid friction clutch should be influenced neither via an externally activatable control or control mimic, nor via a bimetallic arrangement.

Even in the event that the friction disc clutch should be designed only as a single-stage clutch, can be realized with a clutch assembly according to the invention with a non-variable fluid friction clutch at least two operating states (speed profiles). In a first operating state, the friction disc clutch is engaged so that the full rotational speed of the secondary side of the fluid friction clutch is transmitted 1: 1 to the output. In a second operating state, the output can be taken over the bearing friction, whereby a bearing standstill and thus a bearing damage is avoided even in this second operating state, ie disengaged friction disc clutch. For the In the event that optional eddy-current means should be realized between the fluid friction clutch and the friction disc clutch, the output is entrained via these eddy-current means when the friction disc clutch is disengaged. In addition, a variant in which the eddy-current means can be switched on or off can also be implemented, so that it can be selected whether the output is only carried along via the bearing friction or, alternatively, via the eddy-current means.

It is particularly useful if the friction disc clutch is designed as a simple single-stage clutch, ie a clutch which transmits either the full torque or no torque, whereby it is of course also possible to provide a two-, three- or more-stage clutch as Reibscheibenkupplung, for example, as in the DE 20 2007 004 786 U1 described Reibscheibenkupplung, wherein it is particularly useful if, in the case of the formation of the coupling as a multi-stage coupling eddy current means are provided for generating an eddy current for the purpose of entrainment of a coupling part.

In principle, it is possible to actuate the friction disc clutch pneumatically or hydraulically. However, a variant of the friction disc clutch is particularly preferred as an electromagnetic clutch, in which an armature, in particular an armature disc is adjustable by means of an electromagnet, wherein the friction disc clutch coupled both as energized in the energized state and alternatively in the energized state coupled coupling. d. H. can be realized as a fail-safe coupling. In the case of the formation of the friction disc clutch as a pneumatic clutch or hydraulic clutch can of course also a fail-safe clutch can be realized, for which purpose the clutch, for example, by a spring force, is closed in non-pressurized pneumatic or Hydraulikaktuatormimik.

In the case of the formation of the friction disc clutch as an electromagnetic clutch, it is particularly useful if the drive is arranged axially between an electromagnet arrangement of the friction disc clutch and an armature associated with the armature, which is provided for adjusting a friction disc, the armature, in particular via a return spring preferably permanently is mechanically connected to the secondary side of the fluid friction clutch.

Further advantages, features and details of the invention will become apparent from the following description of a preferred embodiment and from the drawings.

These show in:

1 a schematic representation of a preferred embodiment of a clutch assembly, which in addition to a formed as an electromagnetic clutch, single stage friction disc clutch comprises a non-variable fluid friction clutch for transmitting the torque from a drive shaft to an auxiliary unit, here a fan of an engine cooling, and

2 a functional diagram showing the slip of the clutch assembly in different operating modes.

In the figures, like elements and elements having the same function are denoted by the same reference numerals.

In 1 is highly schematic one embodiment of a clutch assembly 1 shown. This includes a drive shaft driven by an internal combustion engine, not shown 2 at the free end of a primary part 3 (Rotor) of a fluid friction clutch 4 is rotationally fixed. In the illustrated embodiment, the fluid friction clutch is 4 (Viscous coupling) to a non-variable, ie neither controllable nor controllable coupling. The primary part 3 rotates, driven by the drive shaft 2 relative to a secondary part 5 the fluid friction clutch 4 , where the secondary part 5 from a housing of the fluid friction clutch 4 which is about a bearing 6 rotatable on the drive shaft 2 is stored, and which is filled with a torque transmitting fluid. The torque transmission between the primary part 3 and abutment 5 takes place via the fluid provided in between, in particular an oil.

Furthermore, the clutch arrangement comprises 1 designed as an electromagnetic clutch friction disc clutch 7 , which in the embodiment shown with the fluid friction clutch 4 is connected in series.

The trained as single-stage electromagnetic clutch friction disc clutch 7 includes a stationary, energizable solenoid assembly 8th relative to the drive shaft 2 over a (further) camp 9 is rotatably mounted.

Axial between the (only half shown in section) electromagnet assembly 8th and the fluid friction clutch 4 there is a (in half only shown on average) output 10 that has an output bearing 11 rotatable on the drive shaft 2 is stored. In the embodiment shown, the output is 10 from a fan 12 formed, but may alternatively also, for example as Pulley or be designed as part of an alternative accessory.

On the from the electromagnet assembly 8th opposite side of the output 10 So axially between the output 10 and the secondary side 5 the fluid friction clutch 4 there is an anchor formed as an anchor plate 13 the friction disc clutch 7 , which is an axially adjustable friction disc 14 carries, which cooperate with an opposing, driven-side friction disc 15 is designed and arranged. The anchor 13 is via a return spring 16 on the secondary side 5 the fluid friction clutch 4 established. Preferred is a variant in which the armature disc directly the axially adjustable friction disc 14 forms. In other words, in this preferred embodiment, the armature disc is integral with the friction disc 14 educated. It is likewise possible and preferred for the driven-side friction disk 15 in one piece with the downforce 10 train, so in this embodiment, the output has 10 at the same time the function of friction means or the friction disc 15 ,

When energizing the solenoid assembly 8th becomes the anchor 13 including friction disc 14 against the restoring force of the return spring 16 axially on the output 10 moved to and in this way frictionally engaged with the driven-side friction disc 15 connected, ie coupled.

The secondary side 5 the fluid friction clutch 4 are magnetic means 17 assigned in the form of a permanent magnet, which in the embodiment shown at the output 10 is arranged, but alternatively also on the secondary side of the fluid friction clutch 4 can be arranged. The magnetic means 17 by inducing eddy currents provide for the generation of a magnetic opposing field, so that the output 10 That is, in the embodiment shown, the fan 12 , with uncoupled electromagnet arrangement 8th from the permanently, ie constantly driven secondary side of the fluid friction clutch 4 is taken in the circumferential direction, whereby always an increased speed on the output 10 (here fan) is applied, which in turn is a basic cooling power generated by the fan. Theoretically conceivable, of course, a clutch assembly without designed and arranged for entrainment magnetic means 17 , These can, as mentioned in an alternative embodiment also on a moving part of the fluid friction clutch 4 can be arranged, in which case eddy currents are induced in the output. In the case of the waiver of the eddy current means bearing damage to the output bearing with advantage 11 anyway avoided because of the downforce 10 bearing friction (in comparison with a variant with eddy current at reduced speed) is carried along. To avoid a magnetic short circuit, or to force the magnetic flux over the working air gap is in the output 10 a magnetic separation 20 between two radial sections of the output 10 intended.

Most preferably, the magnetic means comprise 17 a plurality of circumferentially adjacent permanent magnets alternating polarity, wherein it is even more preferred if these permanent magnets via a ferromagnetic yoke element 18 , in particular a non-return ring, are flux-conductively connected to each other, wherein the ferromagnetic return element preferably on that of the fluid friction clutch 4 remote side of the permanent magnets is located. Preferably, the permanent magnet opposite in the secondary side (secondary part 5 ) of the fluid friction clutch 4 an electrical conductor, in particular a metal ring, assigned, in which the eddy currents are induced by the relative movement between the conductor and the permanent magnet. To minimize the magnetic losses, the electrical conductor material, in particular on the side facing away from the permanent magnet side, a ferromagnetic non-return element 19 , in particular a ferromagnetic return ring, are allocated, which, for example, to the primary part 3 determined, ie relative to the secondary part 5 may be arranged to rotate or the component of the secondary part 5 can be.

In the 1 shown clutch assembly can be operated in two operating states. In a first operating state, the electromagnet arrangement 8th energized and thus in the illustrated embodiment, the friction disc clutch 7 engaged, so that the permanently driven fluid friction clutch 4 frictionally connected via the friction disc clutch to the output. This will do this on the secondary side 5 the fluid friction clutch 4 applied torque directly connected to the output via the frictional engagement. This operating state is indicated by the curve II in the diagram according to FIG 2 characterized. In the diagram according to 2 is the fan speed (vertical axis, y-axis) given in revolutions per minute plotted against the input speed (abscissa, x-axis), ie the speed of the drive shaft in revolutions per minute. The curve I represents the theoretical, with the execution according to 1 unrealizable case is that the drive shaft speed corresponds to the fan speed. The differential speed between the curve I and the curve II is due to the inevitable slip between the primary and secondary side of the fluid friction clutch 4 ,

A second operating state is that the friction disc clutch 7 is decoupled. In this case, the fluid friction clutch is 4 not frictionally via the friction disc clutch 7 with the downforce 10 connected. The downforce 10 is compared to the operating state 1 at reduced speed due to the magnet means 10 from the secondary side of the fluid friction clutch 4 dragged. This is in the diagram according to 2 visualized via the curve III. It can be seen that, overall, in operating state III a greater slip prevails, due to the addition of the slip of the fluid friction clutch 4 and the slip of the between fluid friction clutch 4 and downforce 10 realized eddy current coupling.

The curve IV indicates an operating state for a variant without eddy current means, in which the output is entrained exclusively by the bearing friction. This operating state can also be realized in a clutch arrangement with turbulence means, in the event that the turbulence means are arranged switched off. In any case, at least two operating states can always be realized with the exemplary embodiment shown, namely the operating states according to the curves II and III in a clutch with (permanent) eddy-current means and the operating states according to the curves II and IV in a variant without eddy-current means. In one variant embodiment with switchable eddy current means all operating conditions II, III and IV can be realized. Other operating conditions can be realized in the formation of the friction disc clutch as a multi-stage, in particular as a two-stage, three-stage or four-stage clutch.

LIST OF REFERENCE NUMBERS

1

clutch assembly

2

drive shaft

3

primary part

4

Fluid friction clutch

5

secondary part

6

camp

7

friction disc clutch

8th

Solenoid assembly

9

camp

10

output

11

output bearing

12

fan

13

anchor

14

friction

15

friction

16

Return spring

17

Magnetic means for generating eddy currents

18

Return element

19

Return part

20

magnetic separation

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• EP 0317703 A2 [0002]
• DE 3203143 C2 [0002]
• DE 4207710 A1 [0002]
• US 4,305,491 [0005]
• EP 1248007 B1 [0005]
• DE 202007004786 U1 [0018]

Claims (10)

Coupling arrangement for transmitting a drive torque from a drive shaft ( 2 ) on an accessory, in particular on a fan ( 12 ), a motor vehicle, comprising a drive shaft ( 2 ), an output ( 10 ) and a switchable friction disc clutch ( 7 ), characterized in that the coupling arrangement ( 1 ) in addition to the friction disc clutch ( 7 ) for transmitting torque from the drive shaft ( 2 ) on the output ( 10 ) a fluid friction clutch ( 4 ). Coupling arrangement according to claim 1, characterized in that the fluid friction clutch ( 4 ) and the friction disc clutch ( 7 ) are arranged in series, so that the power flow from the drive shaft ( 2 ) to the accessory both by the fluid friction clutch ( 4 ) as well as by the friction disc clutch ( 7 ) runs. Coupling arrangement according to one of claims 1 or 2, characterized in that the fluid friction clutch ( 4 ) in the torque transmission direction between the drive shaft ( 2 ) and the friction disc clutch ( 7 ) is arranged. Coupling arrangement according to one of the preceding claims, characterized in that the liquid friction disk clutch by means of the friction disk clutch ( 7 ) for transmitting torque frictionally to the output ( 10 ) can be coupled and uncoupled. Coupling arrangement according to one of the preceding claims, characterized in that the fluid friction clutch ( 4 ), preferably in the region of the output ( 10 ) and / or the fluid friction clutch ( 4 ), magnetic means ( 17 ), in particular permanent magnets, for generating eddy currents for entrainment of the output ( 10 ) assigned. Coupling arrangement according to one of the preceding claims, characterized in that on a secondary side of the fluid friction clutch ( 4 ) Return means, in particular a return spring ( 16 ), the friction disc clutch ( 7 ). Coupling arrangement according to one of the preceding claims, characterized in that the fluid friction clutch ( 4 ) is designed neither as a controlled nor as a regulated, in particular not as a self-regulated with a bimetallic coupling. Coupling arrangement according to one of the preceding claims, characterized in that the friction disc clutch ( 7 ) is designed as a single-stage clutch, or as, preferably vortex flow means for torque transmission comprehensive, multi-stage coupling. Coupling arrangement according to one of the preceding claims, characterized in that the friction disc clutch ( 7 ) is designed as an electromagnetic, pneumatic, or hydraulic clutch. Coupling arrangement according to one of the preceding claims, characterized in that the output ( 10 ) axially between an electromagnet arrangement ( 8th ) of the friction disc clutch ( 7 ) and one of the electromagnet arrangement ( 8th ) associated anchor ( 13 ), which is preferably mechanically connected to the secondary side of the fluid friction clutch ( 4 ) connected is.

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