EP0656990B1 - Device for driving a motor vehicle accessory group, in particular the radiator fan of an internal combustion engine - Google Patents

Abstract

A planetary gear (15b) mounted on a central shaft (29b) that turns together with the crankshaft (17b) drives an accessory group of a motor vehicle, in particular a radiator fan (1b) of an internal combustion engine temperature-dependent controllable by a hydraulic friction clutch (5b). The planetary gear has three gear components rotatable with respect to each other together with the shaft (29b) around a common axis of rotation (27b), which form a sun wheel (33b), a ring gear (35b) and a planet carrier (39b) provided with planet wheels (43b). The gear components are rotatively mounted with respect to each other on rolling bearings (49b, 51b, 59b) clamped between bearing members (167, 169) of the shaft (29b) in a common bearing force path together with parts of the gear components, in order to compensate axial play. Lubricant conveyor means (91b) associated to the planetary gear (15b) supply liquid lubricant to the rolling bearings (49b, 51b, 59b) when the gear components rotate with respect to each other. The planetary gear (15b) is designed as a gear whose speed of rotation can be changed-over, and locked in direct drive. In order to allow the rolling bearings (49b, 51b, 59b) exposed to the variable motion in direct drive to be lubricated in spite of being locked, the rolling bearings are arranged in radially inwardly open but radially outwardly tight lubricant pockets (129, 133, 141) which extend over the radially inner running races of the rolling bearings and which are filled with lubricant when the internal combustion engine is started by temporarily operating the planetary gear (15b) in a speed increasing mode.

Description

The invention relates generally to a device for driving a cooling fan of an internal combustion engine, according to the preambles of claims 1, 7 (EP-A-0129685).

Usually, a plurality of auxiliary units driven by the internal combustion engine are provided in a motor vehicle, such as, for example, an electric generator, oil pumps, compressors for compressed air or air conditioning units, or a cooler fan or cooler fan. Auxiliary units of this type are often driven from the internal combustion engine via a belt transmission. The belt transmission, which can be a transmission gear or a reduction gear, adjusts the speed of the internal combustion engine to the operating speed of the auxiliary unit.

Radiator fans are usually via fluid friction clutches controlled temperature-dependent, as described for example in DE-A-38 07 109. The fluid friction clutch turns the radiator fan off at low temperatures and on at high temperatures. However, the cooling capacity requirement also depends on the driving speed and the resulting cooling of the wind. The power that can be transferred from the fluid friction clutch to the radiator fan also depends on the engine speed. In order to be able to transmit a sufficiently large torque via the clutch at a low engine speed, it is often necessary to rapidly translate the engine speed for driving the radiator fan. On the other hand, it is desirable to reduce the speed at high speeds to save power.

In a first aspect, it is an object of the invention to provide a drive device for a radiator fan of a motor vehicle, the speed of which can be adapted better than previously to the cooling requirements of the internal combustion engine of the motor vehicle.

In the first aspect, the invention is based on a device for driving a radiator fan of an internal combustion engine of a motor vehicle, comprising: a gearbox in the drive path of the radiator fan and a fluid friction clutch connected to the gearbox for in particular temperature-dependent control of the operation of the radiator fan.

The device according to the invention is characterized by the features of claims 1 and 7, respectively.

The combination of the fluid friction clutch with a gearbox with changeable speed ratio allows the cooling capacity of the radiator fan to be better adapted to the current operating conditions of the motor vehicle, in particular its driving speed and engine speed. While the fluid friction clutch is expediently controlled as a function of temperature, as before, the braking device can be controlled as a function of an engine speed threshold and / or a driving speed threshold via an electrical control, for example. The coaxial structure of both the fluid friction clutch and the planetary gear allows both components to be arranged coaxially and, if necessary, directly connected to an output end of the crankshaft of the internal combustion engine. It goes without saying that the planetary gear can also be offset against the crankshaft axis and can optionally be connected to the crankshaft via a belt transmission.

In a first variant, the braking means are designed as a controllable clutch, in particular as an electromagnetic clutch, by means of which the first transmission component can be blocked relative to a component that is stationary relative to the internal combustion engine. The second gear component is connected to the third gear component via a one-way clutch and to the radiator fan via the fluid friction clutch. In this embodiment, with a sufficiently small installation space, a transmission gear can be built up which, when the clutch is engaged, translates rapidly, but with the clutch controlled in the open state via the additional one-way clutch, however, it allows the radiator fan to be driven directly at the engine speed. At low engine speeds, the fan speed can be increased in this way without having to accept increased drive losses.

The second gear component comprising the ring gear is preferably firmly connected to the fluid friction clutch. This applies in particular if the drive from the internal combustion engine is via the third gear component, i.e. the planet carrier. The transmission ratio achievable in this configuration with a stationary sun gear is particularly well adapted to the operating speed range of the internal combustion engine on the one hand and of the radiator fan on the other.

Especially when the central shaft is in rotary drive with the crankshaft of the internal combustion engine, the fluid friction clutch can be connected to the structural unit in a particularly simple manner with the second gear component forming the ring gear. In this case, the central shaft can in particular also be connected coaxially and permanently directly to the crankshaft.

Planetary gears mounted directly on the crankshaft are exposed to comparatively high mechanical loads due to the irregularity of the crankshaft rotation. Last but not least, vibrations occur on the crankshaft both radially and axially, since the crankshaft is generally floating in plain bearings. Signs of wear on the electromagnetic clutch can be considerably reduced if the electromagnetic clutch comprises an axially movable armature unit which is connected to the first gear component in a rotationally fixed manner and a magnetic winding unit which surrounds the central shaft in a ring shape and which is guided radially or indirectly via at least one roller bearing on the central shaft and via one both axially and radially elastic torque arm is rotatably guided on a component of the internal combustion engine. In this way, the magnetic winding unit can follow the axial and radial oscillatory movements of the crankshaft and is nevertheless held on the internal combustion engine in a rotationally fixed manner. The torque arm is expediently a sheet metal part which is rigid in the circumferential direction and extends in a first section in the direction normal to the axis of rotation and in a second section in the direction of the axis of rotation.

In this context, it has proven to be particularly favorable if the armature unit comprises at least one armature plate which is fixedly connected to the first gear component, for example riveted, by means of an axially elastic leaf spring arrangement. It has been shown that such a suspension of the anchor plate wears little even with large vibrations of irregularity.

In a second embodiment of the invention, the fluid friction clutch also forms the controllable one Brake means and exerts a braking torque of variable magnitude on one of the transmission components. The clutch torque of the fluid friction clutch allows not only to control the performance of the radiator fan, but also its drive speed. Control is conventionally carried out by changing the degree of fluid filling in the shear gaps of the fluid friction clutch, but preferably by means of external control means, such as pumps or valves, in order to be able to specify a certain temperature characteristic of the clutch operation, or additionally or alternatively the clutch operation depending on the engine speed or to be able to vary the driving speed. The fluid friction clutch can be combined with the planetary gear in the manner explained above for an electromagnetic clutch, so that stationary feed lines can be used for the feed of the shear fluid.

The radiator fan is expediently connected in a rotationally fixed manner to the second gear component forming the ring gear, while the fluid-friction clutch is connected to one of the two other gear components depending on the gear component used for the drive, but in particular to the first gear component forming the sun gear. It is understood that the fluid friction clutch, which acts as a "fluid friction brake" in this embodiment, can also exert its braking action between two of the gear components in order to block the planetary gear as a whole and to achieve a 1: 1 drive of the radiator fan. Preferably, however, the fluid friction clutch is connected in a rotationally fixed manner to a stationary component of the internal combustion engine.

From DE-C-35 08 808 it is known a speed switchable To mount planetary gear on an extension of the crankshaft of an internal combustion engine and to use it for the speed adjustment of an auxiliary unit of the motor vehicle. The planetary gear is designed as a reduction gear and drives the sun gear ending in a pulley via its planet gear carrier, which is connected in a rotationally fixed manner to the extension of the crankshaft. The ring gear of the planetary gear, which meshes with the planet gears as well as the sun gear, can be blocked relative to the stationary motor housing via an electromagnetic clutch. A one-way clutch connects the planet carrier with the ring gear for direct drive.

In the known planetary gear, the ring gear and the sun gear are mounted on one another and on the extension of the crankshaft via conventional deep groove ball bearings. The belt pulley forming the output element of the planetary gear also forms a housing enclosing the planetary gear and is filled with lubricant in order to be able to keep the wear low even with a comparatively high drive power to be transmitted.

Since the transmission rotates together with the crankshaft, the lubricant filling is exposed to centrifugal forces. In order to be able to reliably lubricate all ball bearings and the gears of the planetary gear, the housing would have to be completely filled with lubricant. This is undesirable in itself, since it increases the weight of the planetary gear and even slight lubricant losses in operation lead to the dry running of the ball bearings arranged essentially radially on the inside in the housing.

It has already been suggested that the planetary gear to fill the receiving lubricant chamber only partially with lubricant, for example oil, and to convey the lubricant thrown outwards by the centrifugal forces during operation back into the radially inner region of the lubricant chamber by means of a conveying device. The conveying device can be a pump or a scoop pipe, which is driven by the relative movement of the gear components of the planetary gear, after the gears of the planetary gear only roll against one another in the reduction or step-up mode.

However, it has been found that the above-described attempt to solve the lubrication problem can only reduce the wear in the reduction or step-up mode of the planetary gear. With direct drive and a bridged planetary gear, the planet gears do not rotate continuously, but due to the non-uniformity of the crankshaft movement, the gear components vibrate relative to one another in a limited range of rotation angles. However, since the lubricant delivery stops when the planetary gear is bridged, the lubricant is centrifuged off, which means that the roller bearings and gear components located radially outside of the lubricant fill level tend to run dry. It has been shown that, in particular, the inner raceways of the roller bearings are worn out after a short time if the planetary gear is operated exclusively in a bridged state for too long periods.

With a view to keeping the life-reducing wear very low, it is proposed that at least one of the gear components is mounted on at least one roller bearing, the roller bodies of which are guided between a radially inner raceway and a radially outer raceway.

Furthermore, it is provided that the planetary gear has a partially filled with lubricant, sealed to the outside lubricant chamber, which encloses at least the sun gear, the ring gear and each planet gear, that within the lubricant chamber at least one radially open, but otherwise closed, annular lubricant pocket is divided, in which the outer and inner raceways of at least one roller bearing are essentially completely accommodated, and in that the planetary gear has a lubricant delivery device which delivers the lubricant from a radially outer region of the lubricant chamber to a region radially inside the sun gear and each lubricant pocket.

The lubricant delivery device conveys the lubricant, which is expediently liquid lubricant, such as oil or the like, during the reduction or translation operation of the planetary gear in the region of the central shaft, from where it is lubricated by centrifugal force Areas distributed. If necessary, additional channels are provided so that the lubricant can be distributed in a targeted manner. In order to avoid the Direct drive, in order to be able to lubricate the inner raceways of the roller bearings, even in this operating situation, the roller bearings run in a lubricant bath inside the lubricant pockets. The lubricant pockets, which can partially empty when the transmission is at a standstill after they are open radially inward, are filled with the first gear ratio or reduction operating phase of the planetary gear which follows the standstill. If necessary, provision can be made for the planetary gear to be switched on in certain operating situations, for example when the internal combustion engine is started, for example for a short period of time. In any case, however, the raceways of the rolling bearing are subsequently prevented from running dry and wearing out.

Although the above-described planetary gear is particularly suitable for driving the above-described radiator fan, it should be emphasized that it is also suitable for driving other auxiliary units, such as an electric generator, a pump for a hydraulic or pneumatic system, an air conditioner or the like. The device according to the invention is This is particularly advantageous if the planetary gear is coupled directly to the crankshaft, i.e. it is not driven from the crankshaft via a vibration-damping belt drive. The drive via a belt drive is also possible. It is understood that separate lubricant pockets can be assigned to the individual roller bearings. However, more or less closely adjacent bearings or other components at risk of wear can also be accommodated in a common lubricant pocket. Preferably, all of the rolling bearings provided for the storage of the individual gear components relative to one another are accommodated in lubricant pockets of the type described.

The lubricant pockets can be realized particularly simply in that a first component forming the outer raceway is fixedly, in particular integrally, connected axially on one side of the rolling elements to an annular shoulder, which extends radially inward beyond the smallest diameter of that provided on a second component inner career extends beyond. These components can be bearing rings of conventional roller bearings, but expediently, however, the raceways are also integrally molded into components that are otherwise required for the function of the planetary gear, in order to save installation space and additional means for fixing the bearings. It goes without saying that the annular shoulder and the first component forming the outer raceway can be connected to one another in one piece, but it can also be two separate but firmly connected parts, for example in a press fit.

The ring shoulder is preferred on that of the planet gears axially facing side of the outer raceway is provided, wherein the first component on the side axially facing away from the planet gears is either sealed with a sealing ring against the second component or is rotatably and tightly connected to a side wall of the lubricant chamber. In this way, components required for sealing the lubricant chamber can be used anyway. However, this type of sealing offers particular advantages if, as will be explained in more detail below, the construction is such that the rolling bearings provided for mounting the gear components are clamped axially to compensate for play.

Especially if, in addition to one of the rolling bearings, other components to be lubricated, such as a one-way clutch or the like, are to be accommodated in one of the lubricant pockets, assembly problems can arise if the surfaces to be lubricated cover the annular shoulder in the direction of installation. In a preferred embodiment it is therefore provided that the annular shoulder has an annular flange made of elastic material which projects radially inwards and engages in a peripheral recess of the second component. Such an elastic ring flange can also be installed across undercuts. This is particularly advantageous when raceways or the like are to be integrally formed on the second component.

In particular, embodiments that are to be mounted directly on the crankshaft of the internal combustion engine are exposed to particularly high vibrations and irregularities in the rotary movement. Since the crankshaft is normally supported in plain bearings, that is, it "floats" on an oil film, those caused by the firing order are Non-uniformity or torsional vibration overlaps both radial and axial vibrations. This is especially true for diesel engines and here especially diesel engines for trucks. In a preferred embodiment it is provided that the gear components on both sides of the area in which each planet gear rotates around the sun gear are rotatably mounted on roller bearings whose components forming the raceways together with components of at least one of the gear components in a common support force path between two in are axially spaced opposite stop members of the central shaft axially substantially free of play. It is hereby achieved that the gear components mounted on the roller bearings are essentially axially free of play with respect to one another and accordingly there is no impact load on the roller bearings due to gear components moving axially or radially relative to one another. All of the roller bearings involved in the bearing of the gear components are preferably included in the common support path. The roller bearings are preferably shoulder bearings or angular contact bearings, ie roller bearings with at least one raceway which generally runs obliquely to the axis of rotation. The advantage of these roller bearings is that their raceways, which are inclined anyway, can be used to form the lubricant pocket.

The central shaft that supports the planetary gear can be a stationary shaft, in particular if the planetary gear is arranged separately from the crankshaft and is driven, for example, by a belt drive or the like. In an expedient embodiment, however, it is provided that the central shaft is arranged rotatably about the axis of rotation and that one of the gear components via connecting means, which allow an axial movement is connected in a rotationally fixed manner to the central shaft, while the two other gear components are arranged in the supporting force path via roller bearings, the inner and outer raceways of which permit axial movement relative to one another, relative to one another and to the central shaft. In this way, the transmission components are in and of themselves loosely guided on the central shaft, and axial play is only compensated for by the axial support in the support force path.

A particularly simple variant for a translating planetary gear of the latter type is obtained when the third gear component is seated on the central shaft in a rotationally fixed manner and the first gear component is mounted on the central shaft with a first of the roller bearings, the second gear component being supported by a second one of the roller bearings the third gear component and a third of the roller bearings on the first gear component. Such an embodiment is compact, can be easily installed and can be sealed without problems.

The lubricant delivery device can operate in the manner of a gear pump, the stator and rotor of which are each connected to different gear components, so that they rotate relative to one another in the gear unit's transmission mode. The first gear component comprising the sun gear preferably carries the pump device so as to bring the lubricant particularly close to the central shaft. The pump device can be, for example, a radially extending scoop tube, which skims the lubricant from the radially outer region during the relative rotation of the sun gear and the ring gear and conveys it radially inwards. In the radially inner area, it is expedient between the first Gear component and the central shaft an axially extending lubricant channel, for example in the form of an annular gap or at least one axially extending groove, is provided, which distributes the lubricant in the axial direction in the area of the individual lubrication points. The axial lubricant channel expediently ends at one end in the lubricant pocket of the first rolling bearing. The other end of the axial lubricant channel can be connected to a radially outwardly closed, annular lubricant pocket of the third gear component, from which a radial channel leads radially within the region of each planet gear to the bearing of the planet gear. With the aid of such a lubricant pocket, the lubricant emerging from the axial lubricant duct can be distributed uniformly in the circumferential direction in a simple manner, while the radial ducts emanating from the lubricant pocket ensure targeted lubrication of the planet gear bearings.

Fig. 1

eine Teildarstellung eines Axiallängsschnitts einer Antriebsbaueinheit für einen Kühlerlüfter einer Brennkraftmaschine;

Fig. 2

eine schematische Darstellung der Baueinheit;

Fig. 3

ein Diagramm, das die Abhängigkeit der Antriebsleistung P des Kühlerlüfters von der Drehzahl n des Kühlerlüfters zeigt;

Fig. 4

eine schematische Darstellung einer Variante einer Antriebsbaueinheit für einen Kühlerlüfter und

Fig. 5

eine Teildarstellung eines Axiallängsschnitts einer noch weiteren Variante einer Antriebsbaueinheit für einen Kühlerlüfter.

Fig. 1 zeigt eine Antriebsbaueinheit für einen Kühlerventilator bzw. Kühlerlüfter 1 einer nicht näher dargestellten Brennkraftmaschine eines Kraftfahrzeugs. Der Kühlerlüfter 1 sitzt in an sich bekannter Weise auf einem Gehäuse 3 einer allgemein mit 5 bezeichneten Flüssigkeits-Reibungskupplung herkömmlicher Bauart, wie sie anhand von Fig. 5 noch näher erläutert werden soll. Wie in Fig. 2 schematisch dargestellt, ist das Gehäuse 3 an einem Zapfen 7 drehbar gelagert und bildet zusammen mit einer fest an dem Zapfen 7 gehaltenen Läuferscheibe 9 Scherspalte 11, die, wenn sie mit einem viskosen Scherfluid gefüllt sind, das auf den Antriebszapfen 7 wirkende Antriebsmoment auf das Gehäuse 3 und damit den Kühlerlüfter 1 übertragen. Der Füllpegel in den Scherspalten 11 bestimmt das übertragbare Drehmoment und wird über eine nicht näher dargestellte Ventilanordnung von einer mechanischen Temperatursteuerung 13, beispielsweise einer Bimetallsteuerung, temperaturabhängig gesteuert, wie dies beispielsweise in der DE-A-38 07 109 beschrieben ist. Bei tiefen Temperaturen wird das Scherfluid aus den Scherspalten 11 dynamisch aufgrund der Relativdrehung zwischen der Läuferscheibe 9 und dem Gehäuse 3 abgepumpt, womit der Kühlerlüfter 1 von dem Abtriebszapfen 7 abgekuppelt ist, während die Scherspalte 11 bei hohen Temperaturen gefüllt und der Kühlerlüfter 1 damit eingeschaltet ist.The invention is explained in more detail below with reference to a drawing. Here shows:

Fig. 1

a partial view of an axial longitudinal section of a drive assembly for a radiator fan of an internal combustion engine;

Fig. 2

a schematic representation of the unit;

Fig. 3

a diagram showing the dependence of the drive power P of the radiator fan on the speed n of the radiator fan;

Fig. 4

a schematic representation of a variant of a drive assembly for a radiator fan and

Fig. 5

a partial view of an axial longitudinal section of yet another variant of a drive assembly for a radiator fan.

1 shows a drive unit for a radiator fan or radiator fan 1 of an internal combustion engine, not shown, of a motor vehicle. The radiator fan 1 is seated in a manner known per se on a housing 3 of a conventional type of fluid friction clutch, generally designated 5, as will be explained in more detail with reference to FIG. 5. As shown schematically in FIG. 2, the housing 3 is rotatably mounted on a pin 7 and, together with a rotor disk 9 held firmly on the pin 7, forms shear gaps 11 which, when filled with a viscous shear fluid, act on the drive pin 7 acting drive torque to the housing 3 and thus the radiator fan 1 transmitted. The filling level in the shear gaps 11 determines the transmissible torque and is controlled in a temperature-dependent manner by a mechanical temperature control 13, for example a bimetal control, via a valve arrangement (not shown in more detail), as is described, for example, in DE-A-38 07 109. At low temperatures, the shear fluid is pumped out of the shear gaps 11 dynamically due to the relative rotation between the rotor disk 9 and the housing 3, with which the cooler fan 1 is uncoupled from the driven pin 7, while the shear gap 11 is filled at high temperatures and the cooler fan 1 is thus switched on .

The fluid friction clutch 5 is flanged directly to a crankshaft 17 of the internal combustion engine via a switchable planetary gear 15. The planetary gear 15 is designed as a transmission gear and comprises an electromagnetic clutch 19, via which it can be switched on in the drive path between the crankshaft 17 and the drive pin 7 to increase the drive speed or can be bridged for direct drive with the crankshaft speed. The electromagnetic clutch 19 is controlled by a controller 21 (FIG. 2), which in turn responds to further operating parameters of the motor vehicle, in particular the speed of the internal combustion engine detected by a speed sensor 23 and, if appropriate, the driving speed of the motor vehicle detected by a sensor 25, and on the basis of these parameters Operation of the cooling fan 1 optimized.

By monitoring the engine speed, the power loss of the fluid friction clutch 5, as seen over the entire operating speed range, can be optimized or reduced. FIG. 3 shows the power requirement P of the cooling fan 1 as a function of the fan speed n with the engine speed assumed to be constant. Curve A shows the power requirement of the radiator fan 1 alone, that is to say the drive power required for the radiator fan 1 at the outlet of the fluid friction clutch 5, while curves B and C represent the drive power to be used for this purpose at the inlet of the fluid friction clutch 5 at different output speeds. Curve B shows the conditions for the direct drive with the engine speed, while curve C represents the conditions for speed transmission by the planetary gear 15. The power difference indicated by hatching represents the power loss due to slippage in the fluid friction clutch 5. As shown in FIG. 3, the power loss and thus the slippage increases with decreasing transferable power and passes through a maximum. The power loss and its maximum is proportional to the heat development in the fluid friction clutch. By a suitable choice of the switching speed n _s , in which the control 21 via the electromagnetic clutch 19, the planetary gear 15 from the direct gear into the gear ratio switches and by suitable adaptation of the fluid friction clutch 5 to the resulting speed ranges, the power loss can be reduced. Curve C, which is extended into the area of curve B for a better understanding, clearly shows the reduction in power loss compared to a gearbox that only drives the radiator fan at a speed ratio, such as is conventionally used as a belt gearbox for this purpose.

The switchover speed n _s can have a predefined size; however, it can also be varied depending on the driving situation of the motor vehicle, for example depending on its driving speed and the resulting cooling power requirement of the internal combustion engine, for example by increasing the fan speed at a low driving speed and thus low airflow cooling, while reducing it at a high driving speed.

1 shows structural details of the drive assembly explained in principle with reference to FIG. 2. The planetary gear 15 is guided radially and axially on a central shaft 29 which is coaxial with the axis of rotation 27 of the fluid friction clutch 5 and thus of the radiator fan 1. The shaft 29 is coaxial with an end flange 31 and is directly attached to an end face of the crankshaft 17. The planetary gear 15 comprises three gear components rotatable relative to one another about the axis of rotation 27, of which a first gear component comprises a sun gear 33 rotatable relative to the shaft 29, a second gear component, a ring gear 35 rotatable both about the shaft 29 and the sun gear 33 and a third gear component one via a toothing 37 rotatably connected to the shaft 29, generally designated 39 Planetary carrier comprises, on which a plurality of, for example three, planet gears 43 are rotatably mounted axially parallel to the axis of rotation 27 via roller bearings 41. For the sake of simplicity, FIG. 1 shows only one of the planet gears 43 meshing with both the sun gear 33 and the ring gear 35.

The sun gear 33 is connected in a rotationally fixed manner to a double cone 47 via a clutch disc 45, which is toothed both radially on the inside and radially on the outside. The double cone 47 is mounted radially on the inside via a first roller bearing 49 on the shaft 29 and in turn supports one of two housing shells 53, 55 radially on the outside via a second roller bearing 51, between which the ring gear 35 is held by screws 57. The other housing shell 55 is connected via a third roller bearing 59 to a ring part 61 of the planetary gear carrier 39 which surrounds the shaft 29 and is coupled to the ring part 61 via the toothing 37. A further ring part 67 is rotatably connected to the housing half 55 by a cover part 63 coaxially with the ring part 61 a toothing 65 held. The ring parts 61, 67 form, on the one hand, the raceways of the roller bearing 59 and, on the other hand, the engagement surfaces of a one-way or one-way clutch 69 arranged axially between the roller bearing 59 and the planet gears 43.

The electromagnetic clutch 19 comprises a magnetic coil unit 71 which is concentric with the axis of rotation 29 and which is guided centered on the shaft 29 via a roller bearing 73. A reaction torque arm 75, which is rigid in the circumferential direction and is designed, for example, as a sheet metal part, connects the electromagnet unit 71 in a rotationally fixed manner to a stationary component, for example the engine block of the internal combustion engine. The reaction torque arm 75 extends around both axial and radial vibrations of the crankshaft 17 to be able to accommodate radially in a first section 77 and axially in a second section 79. The electromagnet unit 71 is assigned an armature unit 81 which is held on the double cone 47 in a rotationally fixed but axially movable manner via a toothing 83. In speed-translated operation, the electromagnetic unit 71 is excited, as a result of which the armature unit 81 is attracted and the sun gear 33 is braked against the stationary engine block. The crankshaft 17 drives the planet gear carrier 39 via the shaft 29, the planet gears 43 of which are supported on the stationary sun gear 33 and drive the ring gear at a geared speed. The fluid friction clutch 5, which is centrally attached to the cover part 63 with its drive pin 7, is thus driven via the ring gear 35.

When the electromagnetic clutch 19 is not energized, the sun gear is released and the ring gear 35 and thus the fluid friction clutch 5 is directly connected via the one-way clutch 69, i.e. driven in a speed ratio of 1: 1 by the shaft 29.

The housing halves 53, 55 form a lubricant chamber 85, which is only partially filled with liquid lubricant, such as lubricating oil. The roller bearings 49, 51 arranged axially adjacent to the electromagnetic clutch 19 are sealed by ring seals 87, 89; for sealing on the axially other side of the planetary gear 15, the cover part 63 covers the free end face of the shaft 29. In order to be able to lubricate the radially inner region of the planetary gear 15 despite partial filling, a scoop pipe 91 leading from the radially outer region into the radially inner region conveys the lubricant in the area of the shaft 29. The scoop pipe 91 sits on the double cone 47, that is rotatably connected to the sun gear 33, and scoops the lubricant centrifuged into the outer region and rotating with the ring gear 35 or the housing halves 53, 55 relative to the sun gear 33 in the region of the shaft 29, where it is distributed over axial channels (not shown) and centrifuging back in the area of the rolling bearings and gears.

Variants of drive units for a radiator fan are explained below. Components having the same effect are designated by the reference numerals of exemplary embodiments explained above and are provided with a letter to distinguish them. To explain the structure and mode of operation, reference is made to the preceding description.

FIG. 4 schematically shows a radiator fan 1a, which in turn is driven from the crankshaft 17a of the internal combustion engine via a planetary gear 15a. The planetary gear 15a in turn comprises a planet gear carrier 39a connected in a rotationally fixed manner to a central shaft 29a and having a plurality of planet gears 43a, each of which meshes with a sun gear 33a rotatably enclosing the shaft 29a and a ring gear 35a connected to a unit with housing halves 53a, 55a. In contrast to the assembly of FIGS. 1 and 2, the radiator fan 1 a is connected in a rotationally fixed manner to the ring gear 35 a, and instead of the electromagnetic clutch 19, the fluid friction clutch 5 a is connected to the sun gear 33 a. The fluid friction clutch 5a acts as a "brake", by means of which the sun gear can be braked against the engine block of the internal combustion engine via the reaction torque arm 75a with variable torque. The braking torque is determined by the filling state of the shear gap 11a of the fluid friction clutch 5a. In order to be able to change the filling level, the fluid friction clutch has a Shear fluid supply line 92 is connected to a fluid source 93 which, controlled by the electrical control 21a, changes the filling state of the shear gap 11a. The controller 21a not only responds to the engine speed and possibly the driving speed of the motor vehicle by means of the sensors 23a, 25a, but also to the coolant water temperature or the ambient temperature of the internal combustion engine by means of a temperature sensor 95. The advantage of the variant of the structural unit shown in FIG. 4 is that the speed of the radiator fan 1 a can be varied continuously via the fluid friction clutch 5 a acting as a brake. The operation of the cooling fan 1a can be further optimized by means of suitable speed characteristic curves, for example implemented by characteristic curve fields of the control 21a.

In the exemplary embodiment in FIG. 4, the one-way clutch of the exemplary embodiment in FIGS. 1 and 2 is missing. In this way, the cooler fan 1 a can be switched off when the shear gaps 11 a are completely empty, since the planet gears 43 a can no longer be supported on the freely rotating sun gear 33 a. The maximum speed of the cooling fan la is reached at the maximum fill level of the shear gap la and thus essentially completely stationary braked sun gear 33a.

5 shows a further variant of a drive unit for a radiator fan 1b. The structural unit corresponds to the principle according to the variant of FIGS. 1 and 2, the liquid friction clutch 5b being shown in further details. In particular, FIG. 5 shows that the housing 3b, which is supported by a bearing 97 on the drive pin 7b, through a partition 99 into a working chamber 101 which contains the rotor disk 9b and together with the rotor disk 9b forms the shear gap 11b an axially adjacent storage chamber 103 for the shear fluid is divided. The partition 99 contains a valve hole 105, which is opened or closed in a temperature-dependent manner by a bimetal 109 controlled by a valve plate 107. When the valve hole 105 is open, shear fluid flows into the shear gap 11b. A pump element 111, which acts due to the relative rotation between the rotor disk 9b and the housing 3b, pumps the shear fluid back into the reservoir 103 through an opening 113 of the partition wall 99 for switching off the fluid friction clutch 5b when the valve hole 105 is closed.

Similar to the embodiment of FIGS. 1 and 2, the planetary gear 15b forms a structural unit with the fluid friction clutch 5b and the radiator fan 1b. It is in turn mounted on a central shaft 29b, which is attached via its flange 31b to the crankshaft 17b coaxially with the axis of rotation 27b. It in turn comprises a sun gear 33b rotatable relative to the shaft 29b, a ring gear 35b rotatable relative to the sun gear 33b and the shaft 29b and a planet gear carrier 39b non-rotatably connected to the shaft 29b via the toothing 37b, on which several are connected to the sun gear 33b and via needle bearings 41b the planet gears 43b meshing with the ring gear 35b are mounted axially parallel to the axis of rotation 27b.

The sun gear 33b is connected in a rotationally fixed manner via the double cone 47b to the armature unit 81b of the electromagnetic clutch 19b, the ring-shaped electromagnet 71b surrounding the shaft 29b on the crankshaft side of the planetary gear 15b is guided radially relative to the shaft 29b by means of the ball bearing 73b. The ball bearing 73b, however, is not arranged axially next to the roller bearings 49b, 51b, which are arranged essentially radially one above the other, but is also approximately radial in order to save axial space over these camps. Similar to FIG. 1, the electromagnet unit 71b is assigned a reaction torque arm 75b, which connects the electromagnet unit 71b in a rotationally fixed manner to a stationary component of the internal combustion engine, for example the engine block, and also a radially extending, axially elastic section 77b and an axially extending, radial one elastic portion 79b includes to absorb axial and radial vibrations of the crankshaft 17b. The electromagnetic clutch is in turn controlled by an electrical controller 21b which responds to the speed of the internal combustion engine by means of a speed sensor 23b and optionally to the driving speed of the motor vehicle with a further sensor 25b.

1, the sun gear is not connected to the armature unit 81b via positive toothed clutches or the like, since it has been found that the non-uniformity of the rotational movement of the crankshaft 17b and its axial and radial vibrations lead to high wear on the positive locking teeth. The sun gear 33b is therefore either in one piece or, as shown in FIG. 5, connected by a press fit connection 115 to the component passing between the two roller bearings 49b, 51b, here the double cone 47b. The armature unit 81b has an annularly closed armature plate 117, which may be composed of a plurality of segments, and which is fixedly attached, for example riveted, to the double cone 47b by an optionally also segmented leaf spring element 119. The leaf spring element 119 connects the anchor plate 117 in a rotationally fixed but axially movable manner to the double cone 47b.

The ring gear 35b is between two according to FIG. 1 Housing halves 53b, 55b inserted and fastened with screws 57b, the housing halves 53b, 55b on the crankshaft side via the bearings 51b, 49b on the shaft 29b and on the side remote from the crankshaft via the bearing 59b on the planet carrier 39b, which is in turn seated on the shaft 29b support. A one-way clutch 69b is again provided between the ring part 61b of the planet gear carrier 39b seated on the shaft 29b and a ring part 67b fastened by screws 121 to the housing half 55b.

The housing halves 53b, 55b together with the ring gear 35b enclose a lubricant chamber 85b which is only partially filled with a liquid lubricant, in the radially outer region of which a protruding scoop tube 91b connected non-rotatably to the sun gear 33b projects the lubricant driven outwards by centrifugal forces back into the region of Shaft 29b scoops if the ring gear 35b moves relative to the sun gear 33b in the speed-translating operation of the planetary gear 15b. The scoop tube 91b is connected via a radial bore 123 of the sun gear to an axially extending channel 125 formed radially between the sun gear 33b and the shaft 29b. The channel 125 distributes the lubricant in the axial direction in the planetary gear 15b and opens on the crankshaft side in an annular lubricant pocket 129 formed between the double cone 47 and a bearing ring 127 of the radially innermost rolling bearing 49b, which is sealed to the outside by the ring seal 87b . The radially overlying roller bearing 51b also forms between the double cone 47b and an outer bearing ring 131b of the roller bearing 51b inserted axially from the outside into the housing half 53b, an annular lubricant pocket 133 which is sealed to the outside by the ring seal 89b and which is connected via an outlet 135 in radially inner region of the scoop tube 91b can also be supplied with lubricant. The lubricant pockets 129, 133 are sealed radially outward and are only accessible from the radial inside.

The end of the channel 125 remote from the crankshaft 17b opens into an annular space 137 which serves to distribute the lubricant, from which a channel 139 in the ring part 61b leads into an annular lubricant pocket 141 located between the ring parts 61b, 67b. The lubricant pocket contains the roller bearing 59b including its inner bearing ring 143 placed on the ring part 61b and the one-way clutch 69b, the engagement surfaces of which are formed by regions of the ring parts 61b, 67b lying radially one above the other. On the side remote from the crankshaft, the lubricant pocket 141 is sealed by a sealing plate 145 held with the screws 121 on the ring part 67b, which extends over the end of the shaft 29b remote from the crankshaft, but has an assembly and filling opening closed by a cover 147 in the region of this end. On the side adjacent to the planet gears, an annular sealing plate 149 is inserted between the ring part 67b and the housing half 55b, which carries an annular sealing lip 151 on its inner circumference, which radially inward both via the inner ring 143 and via the radially inner engagement surface of the one-way clutch 69b protrudes in and engages in a circumferential groove 153 of the ring part 61b, but does not touch it. The lubricant pocket 141, which is divided in this way in the lubricant chamber 85b, seals off a radially outwardly sealed volume of lubricant into which all surfaces and components of both the roller bearing 59b and the one-way clutch 69b that are at risk of wear are completely immersed. Even if the planetary gear 15b with the electromagnetic clutch 19b open in is operated in direct gear, the lubricant filling of the lubricant pocket ensures adequate lubrication. Oscillating movements due to the non-uniformity of the crankshaft movement can therefore not lead to wear of the components that move relative to one another.

The roller bearings 49b, 51b are lubricated in an analogous manner even in the direct gear of the planetary gear 15b. The lubricant pockets 129 and 133 are delimited on their sides adjacent to the planet gears 43b by ring shoulders which extend radially inward to the smallest diameter of the inner raceways of the roller bearings 49b, 51b. After initial filling, the lubricant pockets 129 and 133 thus store lubricant which cannot be centrifuged off even in the direct gear of the planetary gear 15b. In this way, running of the roller bearings 49b, 51b and 59b and the one-way clutch 69b is definitely avoided.

When the internal combustion engine is at a standstill, the lubricant pockets 129, 133 and 141 are at least partially emptied due to gravity. In order to refill the lubricant pockets for the operation of the planetary gear 15b, a control 155 is assigned to the controller 21b, which controls the planetary gear 15b either periodically or for certain operating situations of the motor vehicle, for example when starting the internal combustion engine, for a predetermined period of time regardless of the cooling requirements shifts into the gear in which lubricant is conveyed by the scoop pipe 91b.

The annular shoulders provided to form the lubricant pockets 129, 133 can be similar to the lubricant pocket 141, can be realized by additional sealing components; however, they can also be realized by end faces of components already present, for example an end face 157 of the sun gear in the case of the lubricant pocket 129 or by an annular shoulder 159 integrally formed on the bearing ring 131.

The needle bearings 41b of the planet gears 43b are also lubricated. For this purpose, an inner circumferential groove 163 adjoins the distribution annular space 137 via an annular gap 161, from which a radial channel 165 leading to the needle bearing 41b branches off in the region of each planet gear 43b.

The sun gear 33b is lubricated through openings on the radially inner foot of the scoop tube 91b. The ring gear 35b is immersed in the lubricant sump that collects when rotating in the radially outer region of the lubricant chamber 85b.

The bearing arrangement of the planetary gear 15b is made such that all the gear components of the planetary gear 15b against each other and the shaft 29b bearing bearings 49b, 51b and 59b in a common supporting force path between a support shoulder 167 provided on the shaft 29b and a central end of the crankshaft remote from the Shaft 29b screwed mounting nut 169 are arranged without play. The roller bearings 49b, 51b and 59b are all designed as shoulder bearings or inclined bearings, that is to say they generally have raceways which run at an angle to the axis of rotation 27b. All of the components arranged in the supporting force path between the annular shoulder 167 and the fastening nut 169 are axially loose to compensate for play and are tensioned against one another during assembly while compensating for the play. The supporting force path of the roller bearings 49b, 51b and 59b leads from the bearing ring 127 via the roller bearing 49b, the double cone 47b, the roller bearing 51b, the outer ring 131, the housing half 53b, the ring gear 35b, the housing half 55b, the ring part 67b, the roller bearing 59b, the inner ring 143 to a support ring 171, which by means of the fastening nut 169 can be screwed against the ring shoulder 167. The generally obliquely running raceways of the roller bearings 49b, 51b, 59b here extend axially on both sides of the revolving area of the planet gears 43b obliquely outwards in order to be able to form the lubricant pockets 129, 133 and 141 explained above. By compensating the play of the roller bearings 49b, 51b and 59b, an increased service life of these bearings is achieved, even under greater stress due to axial and radial vibrations of the crankshaft 17b, which is normally mounted in slide bearings.

The planetary gear 15b shown in FIG. 5 forms, together with the fluid friction clutch 5b and the radiator fan, a structural unit which is mounted directly on the crankshaft 17b. It is understood that only the planetary gear 15b can be mounted on the crankshaft 17b, while the fluid friction clutch 5b including the radiator fan 1b can be arranged at another location. For the connection, the ring gear 35b can be connected to a separate output element, for example a pulley 173. A separate belt drive can optionally also be provided between the shaft 29b and the crankshaft 17b.

It is further understood that the planetary gear 15b can also be used to drive other auxiliary units of a motor vehicle independently of a fluid friction clutch. Analogously to the embodiment of FIG. 4, the planetary gear of FIG. 5 can also the electromagnetic clutch 19b is replaced by a fluid friction clutch. In this case, the one-way clutch 69b may also be omitted.

Claims (27)

1. Device for driving a radiator fan (1) of an internal combustion engine of a motor vehicle, comprising:

   a) a planetary gear (15) with a sun wheel (33) as a first gear component, a ring gear (35) surrounding the sun wheel (33) as a second gear component and a planet carrier (39) as a third gear component, in which the planet carrier (39) comprises at least one planet wheel (43) meshing with the sun wheel (33) and the ring gear (35) and in which the sun wheel (33), the ring gear (35) and the planet carrier (39) are rotatable with respect to one another about an axis of rotation (27) of a central shaft (29) drivable by the internal combustion engine,

   b) a radiator fan (1) drivable by the planetary gear for rotation about axis (27),

   c) a liquid friction clutch (5) assigned to the radiator fan (1) for the temperature-dependent control of the operation of the radiator fan (1),

   d) controllable braking means (19) for exerting an alterable braking torque on one (33) of the gear components (33, 35, 39), whereby one (39) of the two remaining gear components (35, 39) is connected to the internal combustion engine as a gear input element and the second (35) of the two remaining gear components (35, 39) is connected to the radiator fan (1) as a gear output element,

   characterised in that

   - the sun wheel (33) is rotatably mounted on the central shaft (29),

   - the ring gear (35) surrounding the sun wheel (33) is mounted in the direction of the axis of rotation (27) on both sides of the sun wheel (33) on the central shaft (29),

   - the controllable braking means (19) are assigned to the sun wheel (33) to produce a braking torque between the sun wheel (33) and a stationary component (75), in particular the internal combustion engine,

   - the liquid friction clutch (5) is arranged between the gear output element (35) and the radiator fan (1) for the temperature-dependent rotating coupling of the gear output element (35) with the radiator fan (1).
2. Device according to claim 1, characterised in that the internal combustion engine is connected to the planet carrier (39) as the gear input element and in that the radiator fan (1) is connected to the ring gear (35) as the gear output element.
3. Device according to claim 1 or 2, characterised in that a liquid friction clutch input component (9) is securely connected to the gear output element (35) for joint rotation about the axis of rotation (27), and in that a liquid friction clutch output component (3) is securely connected to the radiator fan (1) for joint rotation about the axis of rotation (27).
4. Device according to one of claims 1 - 3, characterised in that the braking means are designed as a controllable clutch (19), in particular an electromagnetic clutch, by means of which the first gear component (33) can be blocked relative to the stationary component (75) of the internal combustion engine, and in that the second gear component (35) is connected by a free engine clutch (69) to the third gear component (39, 43) and by the liquid friction clutch (5) to the radiator fan (1).
5. Device according to one of claims 1 - 4, characterised in that the electromagnetic clutch (19) comprises an axially movable anchor unit (81) connected rotation-fast to the first gear component (33) and a magnetic winding unit (71) surrounding the central shaft in a ring, which is radially guided by at least one rolling bearing (73) on the central shaft (29) and is guided rotation-fast by an axially and radially elastic torque support (75) on a component of the internal combustion engine.
6. Device according to claim 5, characterised in that the anchor unit (81b) comprises at least one anchor plate (117) which by means of an axially elastic leaf spring arrangement (119) is securely connected axially movably to the first gear component (33b).
7. Device for driving a radiator fan (1) of an internal combustion engine of a motor vehicle, comprising,

   a) a planetary gear (15) with a sun wheel (33) as a first gear component, a ring gear (35) surrounding the sun wheel (33) as a second gear component and a planet carrier (39) as a third gear component, in which the planet carrier (39) comprises at least one planet wheel (43) meshing with the sun wheel (33) and the ring gear (35) and in which the sun wheel (33), the ring gear (35) and the planet carrier (39) are rotatable with respect to one another about an axis of rotation (27) of a central shaft (29) drivable by the internal combustion engine,

   b) a radiator fan (1) drivable by the planetary gear for rotation about axis (27),

   c) controllable braking means (19) for exerting an alterable braking torque on one (33) of the gear components (33, 35, 39), whereby one (39) of the two remaining gear components (35, 39) is connected to the internal combustion engine as a gear input element and the second (35) of the two remaining gear components (35, 39) is connected to the radiator fan (1) as a gear output element,

   characterised in that

   - the sun wheel (33) is rotatably mounted on the central shaft (29),

   - the ring gear (35) surrounding the sun wheel (33) is mounted in the direction of the axis of rotation (27) on both sides of the sun wheel (33) on the central shaft (29),

   - the controllable braking means (19) are assigned to the sun wheel (33) to produce a braking torque between the sun wheel (33) and a stationary component (75), in particular the internal combustion engine,

   - the controllable braking means (19) are designed as a liquid friction clutch (5a), whereby a first liquid friction clutch component is connected rotation-fast to the stationary component (75a), and a second liquid friction clutch component is securely connected to the sun wheel (33) for joint rotation about the axis of rotation.
8. Device according to claim 7, characterised in that the internal combustion engine is securely connected to the planet carrier (39) as the gear input element and in that the radiator fan (1) is securely connected to the ring gear (35) as the gear output element.
9. Device according to one of claims 1 to 8 in which the first (33b) and/or the second (35b) gear component is mounted on at least one rolling bearing (49b, 51b, 59b) the rolling bodies of which are guided between a radially inner running race and a radially outer running race, characterised in that the planetary gear (15b) comprises a lubricant chamber (85b) partly filled with lubricant, sealed to the outside, which surrounds at least the sun wheel, the ring gear and each planet wheel,

   in that inside the lubricant chamber (85b) at least one exclusively radially inwardly open but otherwise sealed annular lubricant pocket (129, 133, 141) is formed separately, in which the outer and the inner running race of at least one rolling bearing (49b, 51b, 59b) are accommodated completely,

   and in that the planetary gear (15b) has a lubricant conveying device (91b) which conveys the lubricant from a radially outer region of the lubricant chamber (85b) into a region radially inside the sun wheel and each lubricant pocket (129, 133, 141).
10. Device according to claim 9, characterised in that a first component (47b, 121, 131) forming the outer running race is connected securely, in particularly integrally, at least on axially one side of the rolling body by a ring shoulder (149, 157, 159), which extends radially inwards over the smallest diameter of the inner running race on a second component (47b, 61b, 127, 143).
11. Device according to claim 10, characterised in that the ring shoulder (149, 157, 159) is provided on the side of the outer running race axially facing the planet wheels (43b) and in that the first component (47b, 61b, 121, 131) is sealed on the side axially averted from the planet wheels (43b) relative to the second component (47b, 127) or is rotation-fast and sealingly connected to a side wall (145) of the lubricant chamber (85b).
12. Device according to claim 10 or 11, characterised in that the ring shoulder (149) comprises a radially inwards projecting annular flange (151) made of elastic material engaging in a peripheral recess (153) of the second component (67b).
13. Device according to claim 12, characterised in that the lubricant pocket (141) delimited by the elastic annular flange (151) also contains a one-way clutch (69b) in addition to the running races of the rolling bearing (59b).
14. Device according to one of claims 9 to 13, characterised in that the gear components (33b, 35b, 39b, 43b) are rotatably mounted relative to one another on rolling bearings (49b, 51b 59b), on both sides of the region, in which each planet wheel rotates around the sun wheel, the components (47b, 67b, 127, 131, 143) forming the running races of which together with components (35b, 53b, 55b) of at least one part of the gear components are fixed axially without play in a common bearing force path between two axially spaced opposite stop elements (167, 179) of the central shaft (29b).
15. Device according to claim 14, characterised in that each of the rolling bearings (49b, 51b, 59b) rotatably guiding the gear components (33b, 35b, 39b, 43b) relative to one another has at least one running race generally diagonally relative to the axis of rotation, and in that this running race extends away from the peripheral region of the planet wheels diagonally radially outwards.
16. Device according to claim 14 or 15, characterised in that the central shaft (29b) is arranged rotatably about the axis of rotation (27b) and in that one of the gear components (39b, 43b) is connected rotation-fast to the central shaft (29b) by connecting means (37b) which permit an axial movement, and the two other gear components (33b, 35b) are arranged in the bearing force path by rolling bearings (49b, 51b, 59b), the inner and outer running races of which permit an axial movement relative to one another and are rotatably guided relative to one another and to the central shaft (29b).
17. Device according to one of claims 9 to 16, characterised in that the third gear component (39b, 43b) sits rotation-fast on the central shaft (29b) and the first gear component (33b) is mounted with a first (49b) of the rolling bearings on the central shaft (29b), and in that the second gear component (35b) is mounted by a second (59b) of the rolling bearings on the third gear component (39b, 43b) and by a third (51b) of the rolling bearings on the first gear component (33b).
18. Device according to claim 17, characterised in that the first gear component (33b) bears a pump device (91b) in particular in the form of a bucket pipe which on a relative rotation between the first (33b) and the second (35b) gear component conveys the lubricant out of the radially outer region of the lubricant chamber (85b) into an axially running lubricant channel (125) radially between the first gear component (33b) and the central shaft (29b)
19. Device according to claim 18, characterised in that the axial lubricant channel (125) enters into the lubricant pocket (129) of the first rolling bearing (49b)
20. Device according to claim 17 or 19, characterised in that the axial lubricant channel (125) on the side axially averted from the first rolling bearing (49b) is connected to a radially outwards sealed, annular lubricant pocket (163) of the third gear component (39b, 43b) from which radially inside the region of each planet wheel a radial channel (165) leads to the bearing (41b) of the planet wheel.
21. Device according to one of claims 17 to 20, characterised in that the internal combustion engine drives the central shaft (29b), the braking means (19b) brake the first gear component (33b) and the accessory group (1b) is connected to the second gear component (35b).
22. Device according to claim 21, characterised in that the accessory group (1b) is designed as a radiator fan and is held in the same axis to the central shaft (29b) on the second gear component (35b).
23. Device according to one of claims 17 to 22, characterised in that a one-way clutch (69b) is arranged in the torque path from the third (39b, 43b) to the second (35b) gear component.
24. Device according to claim 23, characterised in that the one-way clutch (69b) is arranged axially between the second rolling bearing (59b) and the peripheral region of the planet wheel.
25. Device according to one of claims 9 to 24, characterised in that the lubricant conveying device (91b) comprises a pump device that is only effective on a relative movement between the gear components (33b, 35b, 39b, 43b) and in that a control (21b) is assigned to the braking device (19b) which switches the braking device (19b) in predetermined operating states of the motor vehicle, in particular on starting the internal combustion engine, into the position effecting relative rotation.
26. Device according to claim 25, characterised in that the control (21b) switches the braking device (19b) to the starting of the internal combustion engine for a predetermined period of time into the position effecting relative rotation.
27. Device according to claim 25 or 26, characterised in that the planetary gear (15b) forms a transmission and drives a radiator fan (1b).

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