DE202011051969U1 - Eddy current clutch - Google Patents

Abstract

Coupling, in particular for transmitting a torque from a drive shaft (4) driven by an internal combustion engine (3) to an auxiliary unit (5) of a motor vehicle, preferably to an internal combustion engine fan, comprising an eddy current coupling (2) with a first rotatable coupling element (6) which comprises an electrically conductive eddy current section (22) in which eddy currents can be formed and with a second coupling element (7) which is separated from the first coupling element (6) via an air gap (21) and which is relative to the first coupling element (6) is rotatable and is assigned to the magnetic means (9) in such a way that when the first and second coupling elements (6, 7) rotate relative to one another, eddy currents are generated in the eddy current section (22), so that one of the coupling elements driven by a drive shaft (4) (6, 7) dragging the other of the coupling elements (6, 7) in the circumferential direction, thereby k indicates that the magnetic means (9) comprise at least one electromagnet (10), to which the energizing means (14, 15) are assigned, with which the effective energizing of the electromagnet ...

Description

The invention relates to a clutch, in particular for transmitting a torque from a drive shaft driven by an internal combustion engine to an auxiliary unit, for example an internal combustion engine fan, of a motor vehicle according to the preamble of patent claim 1.

From the EP 0 634 568 A1 a clutch for a fan of a motor vehicle internal combustion engine is known in which the fan for direct transmission of engine speed via a friction disc clutch is connected to transmit torque directly to a drive shaft, wherein the fan is entrained with disconnected friction disc clutch by means of an eddy current coupling. The eddy current coupling comprises on two opposite annular regions on one side a magnet disk wheel with permanent magnets and on the opposite side a flat copper circular ring, which is arranged on a flat steel circular ring. The steel ring (reflux ring) amplifies the magnetic field for generating the eddy currents in the copper ring, which improves the efficiency of the eddy current coupling. The slip of the eddy current coupling is fixed by design.

Based on the aforementioned prior art, the present invention seeks to provide a coupling, in particular for transmitting torque from a drive shaft to an auxiliary unit of a motor vehicle, in which the speed of the output is variable or is adjusted as needed.

This object is achieved with the features of claim 1. Advantageous developments 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.

The invention is based on the idea to provide instead of or in addition to permanent magnets for generating eddy currents in an eddy current section of the clutch at least one electromagnet (energiable winding) and assigned to this Bestromungsmittel, which are designed and determined the effective energization (effective magnetflußbeeinflussende current) of the electromagnet Variation, d. H. Influencing (default) to set the slip between the first and the second coupling element. In other words, by a suitable energization of only one or more electromagnets, the magnetic field generated by this / these can be influenced in a targeted manner, which has direct effects on the slip between the first and the second coupling element. With the single-stage or multi-stage clutch according to the invention, the rotational speed of the output and thus, for example, the rotational speed of an internal combustion engine fan can be varied within a wide range independently of the input shaft rotational speed and adapted to the current needs or specifications.

With the coupling according to the invention therefore a precise control and / or regulation of the output speed for demand-driven drive of the auxiliary unit, in particular a cooling fan is possible. The coupling thus enables a variation of the transmitted torque via the variation of the strength of the eddy current generated by the electromagnet.

Under an effective current or effective current flow is understood to mean the magnetic flux relevant current, so the current of the at least one electromagnet, which is available for generating the magnetic field or to the generated magnetic field or the magnetic flux generated in a functional context stands. If the electromagnet is energized, for example, with constant direct currents, then the actual current intensity or current flow is understood as meaning respectively constant current intensity (non-pulsed current). If the electromagnet arrangement is energized, for example, with a PWM signal, then the effective current intensity is to be understood as meaning the mean current intensity resulting or, in a specific time interval.

It is very particularly preferred to set the most different effective current intensities with which the electromagnet can be energized by means of the energizing means with or by different PWM duty cycles, with a PWM output of a motor vehicle control unit being particularly preferred for this purpose. By the PWM duty ratio is meant the ratio in a period between the time proportion in which the current is turned on to the time proportion in which the current is turned off. If the PWM frequency z. B. 1 Hz, the time to be considered (period) is 1 s; 60% PWM then means 0.6 s of power on and 0.4 s of power off. For example, if the frequency is 5 Hz, the time to be considered (period duration) is 0.2 s; 60% PWM means 0.12 s current on and 0.08 s current off. The effective current intensity is the same in both aforementioned examples, only the time base, ie the period duration (time between two rising pulse edges) is different. As also indicated, it is conceivable, instead of PWM-energizing a Use current control device that can output different amounts of constant currents (non-pulsed currents) for energizing the electromagnet.

Likewise, a voltage regulating device can be provided as the energizing means, which can output different levels of constant voltages (not pulsed).

In principle, it is possible to rotatably arrange the electromagnet on the first coupling means, that is to say about the drive shaft, in which case the contacting of the energizing means, for example via slip ring contacts, is possible. However, in order to simplify the construction of the clutch and to increase the reliability, it is preferable to arrange the solenoid in a member separate from the first clutch member (electromagnetic carrier), with respect to the drive shaft and the first clutch member, the magnetic flux being suitable is to be coupled into the first coupling element, in particular in which overlap the first coupling element and a component carrying the electromagnet in the axial and / or radial direction to form a, preferably small air gap.

In the first coupling element, at least two, preferably exclusively two regions of different magnetic polarity are generated by means of the electromagnet, namely a magnetic north pole region and a magnetic south pole region which is non-rotatably connected thereto but magnetically separated from this (largely). The magnetic separation can be realized between the north pole region and the south pole region, for example, via a non-magnetically conductive material which bonds the two regions mechanically tightly together.

It is particularly expedient for the concentration of the magnetic flux at a plurality of circumferentially spaced, preferably circumferentially spaced over an air gap of the winding section in the second coupling element spaced locations on the Nordpolbereich several north poles and form on the Südpolbereich several south poles, preferably the number of north poles of Number of south poles corresponds. In this case, the north and south poles are more preferably arranged relative to one another in such a way that, in the case of a relative movement between the first and the second coupling element in the circumferential direction, the magnetic field in the eddy current section changes. In other words, a magnetic field which is inhomogeneous in the circumferential direction is generated by an appropriate arrangement of the north poles and south poles relative to one another. This can be realized, for example, in that the north poles and the south poles can be arranged alternately in the circumferential direction, wherein north and south poles alternatively overlap in the circumferential direction (of course do not touch to avoid a magnetic short circuit) or are spaced apart in the circumferential direction , It is conceivable to let the north and south poles, which alternate in the circumferential direction, mesh with one another in the manner of a tooth and, in particular, to arrange them in a common radial plane. It is also possible to provide a circumferentially alternating arrangement of north and south poles, when they are spaced in the axial direction with respect to the longitudinal extension of the drive shaft. It is essential to arrange the north and south poles which are acted upon by the electromagnet with a magnetic flux in such a way that a magnetic field which is inhomogeneous in the circumferential direction results, possibly only through interaction with optional permanent magnets to be explained later.

With regard to the arrangement of the north pole region and the south pole region, more precisely the north pole and the south pole relative to the, preferably annular, electrically conductive eddy current section, there are different possibilities. According to a first alternative embodiment, all north and south poles are arranged together on a common radial or a common axial side of the eddy current portion, in which case it is preferred if on the side facing away from the north and south poles (axial or radial side) Eddy current section magnetic guide means (eg., A steel ring), in particular in the form of a return ring are provided to increase the magnetic field or the magnetic field strength in the magnetic means, thus improving the efficiency. According to a second alternative, the north poles are arranged on a first side and the south poles on a second (axial or radial) side facing away from the first (axial or radial) side, so that the magnetic field lines on their way from one of the north poles to one of the South poles do not have to cross the magnetic media twice as in the first alternative, but only once.

In a further development of the invention is advantageously provided that the magnetic means for generating an electromagnetic field in addition to, at least one, preferably only one electromagnet at least one, preferably a plurality of permanent magnet (s), the permanent magnets preferably so relative to the north pole region and the Are arranged south pole region, in particular to the acted upon by the electromagnet north and south poles and can be energized that a resulting from the permanent magnet and the north and south poles magnetic field is stronger or weaker than that exclusively generated by the permanent magnet field.

Dislocated differently, is provided in a further development of the invention to reinforce the magnetic field generated by permanent magnets using the at least one electromagnet by a corresponding energization and arrangement of the north and south poles relative to the permanent magnets or attenuate. Such an embodiment also enables a fail-safe configuration of the eddy current coupling, since eddy currents can also be generated when the electromagnet fails or is not supplied with current, so that in the case of driving a fan wheel cooling of the internal combustion engine is ensured.

With regard to the arrangement of the permanent magnetic north and south poles and the electromagnetic poles relative to each other, there are different possibilities. According to a first alternative, permanent magnetic and electromagnetic pole pairs alternate in the circumferential direction, ie. H. a permanent magnetic north pole is associated with axial or radial distance a permanent magnetic south pole and vice versa. At the same time, an electromagnetic north pole is arranged in the radial or axial direction opposite to a south electromagnetic pole. According to a second alternative, all poles (north and south poles) lying on a common axial side or radial side of the eddy-current means are formed by permanent magnets and all radially or axially opposite poles (north and south poles) by a corresponding actuation by means of the electromagnet. Preferably, a permanent magnetic south pole opposite (preferably axially or radially aligned) arranged an electromagnetic north pole and / or a permanent magnetic north pole an electromagnetic south pole.

With regard to the further embodiment of the clutch, in particular a fan clutch, there are different possibilities.

Thus, it is conceivable to design the coupling as a single-stage eddy-current coupling, that is, as a coupling in which, in addition to the eddy-current mechanism comprising at least one electromagnet, no further coupling mechanism is provided. Alternatively, it is possible and preferred in addition to the eddy current clutch mechanism, i. H. in addition to the eddy current coupling to provide a further clutch mechanism (another clutch), for example, a further eddy current clutch and / or, which is preferably at least one friction disc clutch, etc .. In the case of providing a friction disc clutch can bridge over this, in a conventional manner, the eddy current coupling or be short-circuited, so that 1: 1, the torque can be transmitted from the output shaft to the output.

Preferably, the friction disc clutch comprises a by energizing an electromagnet, in particular axially, adjustable friction disc (armature), which may alternatively be attached to the first or second coupling element of the friction disc clutch.

With regard to structural refinements of a clutch having at least two different shifting mechanisms, namely a solenoid-based eddy-current switching mechanism according to the invention and an electromagnetically actuated friction-disc clutch mechanism, there are fundamentally different possibilities. Thus, it is possible to control the eddy current mechanism and the friction disc switching mechanism by two solenoids which can be energized independently of one another or, alternatively, with suitable magnetic flux guidance via a common, preferably single electromagnet. In the case of providing an electromagnet for the eddy current mechanism and a separate Reibscheibenkupplungselektromagneten these may alternatively be arranged radially or axially adjacent.

Overall, the combination of the slip-variable eddy-current mechanism with a switchable friction disc coupling results in considerable advantages.

For a full variability of the output torque from zero to the maximum eddy current torque is given on the one hand. In addition, a slip-free full connection or switching through the friction disc clutch can be realized. If necessary, can be completely dispensed with the use of permanent magnets, which is preferred.

As already indicated above, it is possible according to a preferred embodiment to switch the friction disc clutch with the at least one, preferably only one, electromagnets of the eddy current clutch, wherein the clutch assembly is then preferably designed so that when exceeding a defined (predetermined) energization (current ) This electromagnet of the friction disc clutch mechanism is actuated, whereby preferably the eddy current clutch mechanism is bridged, so that the full torque is switched through from the drive shaft to the output or on the auxiliary unit. In the above embodiment, the magnetic flux of the electromagnet on the one hand passes through the Reibscheibenkupplungsmechanismus and bridged while - not switched state of Reibscheibenkupplung - the working air gap between an adjustable, preferably by means of a spring rückverstellbaren friction disc and its associated friction partners and additionally passes through the eddy current coupling mechanism, ie between the north and Südpolbereich, and thereby ensures in a relative rotation of the first and the second coupling element of the eddy current coupling to each other in the eddy current portion of the eddy current coupling mechanism eddy currents are generated to thereby mitzuschlep the opposite coupling element in the circumferential direction. The slip, as already explained in detail above, depends on the effective current supply.

In an alternative embodiment, the friction disc clutch comprises at least one, preferably only one, of the at least one, preferably only one, electromagnets of the eddy current clutch separate electromagnet (friction disc clutch magnet), which is preferably energized independently of the electromagnet of the eddy current coupling. As a result, the different electromagnets can be better designed for their specific task and generally designed as a whole smaller or less powerful than a common solenoid. The disadvantage, however, is that a total of more than one solenoid must be provided, preferably with separate control lines.

In the case of the provision of at least two electromagnets (one electromagnet for the friction disc clutch and another electromagnet for the eddy current clutch), there are basically two alternative arrangement possibilities. Thus, the magnets in the radial direction or in the axial direction adjacent, preferably spaced, are arranged, whereby thereby, d. H. in the latter alternative, the axial length of the overall coupling arrangement can be minimized. Alternatively, an axial misalignment, preferably spacing, is possible, thereby minimizing the radial extent, i. H. can be optimized.

Regardless of the specific arrangement, it is advantageous (but not mandatory) that the Reibscheibenkupplungspartner adjacent in the axial direction and the eddy current coupling partners in the radial direction.

It is particularly preferred in a radially adjacent arrangement of the electromagnet and the Reibscheibenkupplungselektromagneten when the Reibscheibenkupplungsomagnet magnet radially inwardly and the electromagnet of the eddy current coupling is arranged radially outward. Preferably, with an axial arrangement of the two electromagnets, the friction disk clutch electromagnet is arranged closer to a friction disk of the friction disk clutch than the axially adjacent electromagnet of the eddy current clutch.

Preferably, the Reibscheibenkupplungsmechanismus (also) between the first and the second coupling element of the eddy current coupling acts, in which case one of the coupling elements carries the adjustable friction and the other coupling element carries or forms the friction partner. Alternatively, the friction disc clutch can be designed as an open or closed clutch when energized.

Be particularly advantageous in the case of providing separate magnets for the eddy current clutch and friction disc clutch has been found if between the axially or radially adjacent magnet, a Magnetleitabschnitt is provided with both the magnetic flux of the electromagnet of the eddy current clutch and Reibscheibenkupplungselektromagneten in radial or axial direction is conductive.

A variant embodiment is preferred in which an adjustable friction disk / armature of the friction disk clutch is arranged on that coupling element on which the eddy current section of the eddy current coupling is also arranged.

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

These show in:

1 a highly schematic representation of a trained as a single-stage swirl clutch clutch, comprising an electromagnet for generating an eddy current in an eddy current portion of a second coupling element,

2 a possible arrangement of north and south poles of the coupling according to 1 in a representation along the line AA,

3 an alternative embodiment of an eddy current coupling, wherein the north and south poles are axially spaced apart and at the same time arranged offset in the circumferential direction,

4 a further alternative embodiment of a formed as an eddy current clutch coupling, are separated in the north and south poles in the radial direction and in the circumferential direction,

5 a possible arrangement of the north and south poles in the coupling according to 4 .

6 a longitudinal sectional view of a clutch, in which all the north and south poles are arranged on a common radial side of the magnet portion of the second coupling element,

7 a sectional view along the section line AA according to 6 .

8th a further alternative embodiment of a coupling, in which in addition to being acted upon by a solenoid north and south poles a plurality of circumferentially arranged permanent magnets are provided,

9 a possible arrangement of the permanent magnets and acted upon by the electromagnet north and south poles for an embodiment according to 8th .

10 a further alternative embodiment of a coupling, in which radially opposite permanent magnetic and electromagnetic poles,

11 a possible arrangement of the formed as a bar magnets permanent magnets and acted upon by the electromagnet north and south poles for the embodiment according to 10 .

12 an embodiment of the coupling, which comprises a variable eddy current mechanism, a friction disc clutch mechanism, wherein the two clutch mechanisms can be operated with separate electromagnets, in the embodiment according to 12 axially spaced,

13 a clutch variant with a friction disc clutch mechanism and a variable eddy current mechanism, wherein each clutch mechanism is associated with a separate solenoid and the electromagnets are radially spaced,

14 an embodiment of a clutch having a variable eddy current mechanism and a friction disc clutch mechanism operable with a common (single) electromagnet,

15 a half-cut, sectional view of a structural design of the coupling variant according to 12 with two axially spaced electromagnets for the eddy current mechanism and the friction disc clutch mechanism,

16 a sectional view along the section line AA according to 15 .

17 a constructive design possibility of the coupling variant according to 13 with two radially adjacent or here spaced electromagnets for the friction disc clutch on the one hand and the eddy current clutch on the other hand,

18 a sectional view along the section line AA according to 17 .

19 a constructive design possibility of the coupling variant according to 14 with a common electromagnet for actuating the friction disc clutch and the eddy current mechanism and

20 a sectional view along the section line AA according to 19 ,

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

In 1 is a clutch 1 , in this case consisting of an eddy current coupling 2 for transmitting a torque from one of an internal combustion engine 3 driven drive shaft 4 on an accessory 5 of a motor vehicle, shown here on a combustion engine fan.

The eddy current coupling 2 includes a rotationally fixed to the drive shaft 4 connected first coupling element 6 to which magnetic poles are to be explained later and a second coupling element 7 which is relative to the first coupling element 6 and the drive shaft 4 rotatable by means of a bearing 8th is stored.

The first coupling element 6 are magnetic means 9 in the form of an electromagnet 10 associated, which on a support member 11 which is about a bearing 12 opposite the drive shaft 4 is stored, so that the drive shaft 4 relative to the stationary with respect to this, ie non-rotatably arranged support member 11 is rotatable.

As it turned out 1 results, overlap the support member 11 and the first coupling element 6 in the radial direction while maintaining a small gap 13 so that of the electromagnet 10 generated magnetic flux in the first coupling element 6 can be coupled. The electromagnet 10 are an energizer 15 assigned, which preferably from a motor vehicle control unit are formed. In the embodiment shown are the Bestromungsmittel 15 for acting on the electromagnet 10 formed with a pulse width modulated current.

When the electromagnet is energized 10 with the help of the energizers 15 is, as mentioned above, that of the electromagnet 10 generated magnetic field coupled into the first coupling element 6 , where then a magnetic north pole area 16 and a magnetic south pole area 17 in the first coupling element 6 form, wherein in the illustrated embodiments, the north pole region 16 radially outside the south pole region 17 is arranged (the reverse arrangement is of course alternatively feasible). North Pole area 16 and South Pole area 17 are separated by a magnetic separation, at least largely magnetically separated from each other to avoid a magnetic short circuit and rotatably connected to each other at the circuit side.

As can be seen from a detailed representation according to 2 are at the magnetic north pole area 16 a plurality of spaced apart in the circumferential direction and in the radial direction, in this case pointing inwards, north poles 19 formed, the toothing in between the radially spaced south poles 20 of the South Pole area 17 intervention. In the radial direction and in the circumferential direction between the north and south poles 19 . 20 is the magnetic separation 18 , Overall, this results in an arrangement of circumferentially alternately arranged north and south poles for generating a inhomogeneous magnetic field in the circumferential direction.

In the axial direction over an air gap 21 spaced apart from the north and south poles is an annular eddy current section 22 arranged in the form of an annular electrical conductor, such as copper, in which in a relative movement of the first and second coupling element 6 . 7 eddy currents are induced to each other.

On the north and south poles 19 . 20 opposite side of the eddy current section 22 are Magnetleitmittel 23 in the form of a return ring, which is the magnetic field in the eddy current section 22 focus.

With rotating first coupling element 6 induce the magnetic fields of the electromagnet in the eddy current section 22 Eddy currents. These eddy currents in turn generate a magnetic field which interacts with the magnetic field of the electromagnet and counteracts this magnetic field such that the second coupling element 7 by the rotation of the first coupling element 6 also in a rotation and that in the same circumferential direction offset (with dragged) is.

By varying the duty cycle of the PWM current, the effective current (effective magnetic field relevant current) and thus the strength of the magnetic field formed by the electromagnet between the north and south poles can be influenced and thus again directly the slip between the first, directly from the drive shaft 4 driven coupling element 6 and the entrained second coupling element 7 , which in the embodiment shown, the output of the clutch 1 forms, on which here the accessory 5 is fixed immediately. In an alternative embodiment, it is conceivable that between the output of the clutch 1 and the accessory torque transmission by means of suitable center body in case of doubt by means of a belt drive.

In the following, further exemplary embodiments of clutches are described, wherein the avoidance of repetition essentially addresses the differences from the preceding exemplary embodiment. In view of the similarities, reference is made to the preceding figures with associated description.

Also in the embodiment according to 3 is one with the help of an energizer 15 energizable electromagnet 10 provided for generating the magnetic field, wherein the first, rotationally fixed to the drive shaft 4 connected coupling element 6 relative to the electromagnet 10 is rotatable and is arranged relative to this, that of the electromagnet 10 generated magnetic field in the first coupling element to form a magnetic north pole region 16 and a south magnetic pole region 17 is coupled. Also in the embodiment according to 3 are the two areas 16 . 17 different magnetic polarity via a magnetic separation 18 magnetically separated from each other and at the same time fixed on this non-rotatably to each other.

In contrast to the embodiment according to 1 are in the embodiment according to 3 the north poles 19 and the south poles 20 on different axial sides of the eddy current section 22 of the second coupling element 7 , wherein the north and south poles are thus spaced in the axial direction. To generate an inhomogeneous magnetic field, these are analogous to the exemplary embodiment according to FIG 2 also offset in the circumferential direction to each other, so that viewed in the circumferential direction north and south poles alternate.

As it turned out 3 results, the second coupling element engages 7 with the eddy current section 22 in the radial direction between the axially spaced north and south poles 19 . 20 one. By rotation of the over the electromagnet 10 acted upon by an electric field coupling element 6 relative to the second coupling element 7 be in its eddy current section 22 Induced eddy currents, which generate a magnetic field, which ensures that the second coupling element 7 is dragged along in the circumferential direction. The slip between the first coupling element 6 and the second coupling element 7 is by adjusting the effective, ie magnetic field influencing energization of the electromagnet 10 influenced or adjustable.

Another alternative embodiment of a clutch 1 is in 4 shown, in contrast to the embodiment according to 3 the north poles 19 from the south poles 20 spaced radially (and not axially).

Axially in the radially spaced north poles 19 and south poles 20 engages the second coupling element 7 with the eddy current section 22 in the axial direction. As in the embodiment according to 3 is both between the north poles 19 and the eddy current section 22 as well as between this and the south poles 20 one air gap each 21 educated.

Out 5 This results in a possible arrangement of the north poles 19 and south poles 20 relative to each other and relative to the annular eddy current portion 22 , It can be seen on the one hand radial spacing of north and south poles 19 . 20 , that is, on different radial sides of the eddy current section 22 are located. At the same time, viewed in a circumferential direction, those of the electromagnet alternate 10 impinged north and south poles.

In the 6 and 7 are shown sectional views of an alternative coupling structure. The coupling 1 serves to torque from a drive motor side driven drive shaft 4 on a second coupling element 7 transferred to. For this purpose, a first coupling element 6 non-rotatable (positive locking) with the drive shaft 4 connected.

The drive shaft 4 is about a designed as a rolling bearing 12 relatively rotatable with respect to the shaft fixedly arranged support member 11 for the electromagnet 10 the carrier component 11 is about a circumferentially slit in the axial direction 13 spaced from the axial direction extending circumferential gap 13 spaced from the first coupling element 6 and a radial gap extending in the radial direction 24 from an inner portion of the first coupling element viewed in the radial direction 6 , About this small column 13 . 24 the magnetic field becomes the first coupling element 6 coupled, forming a magnetic north pole region 16 and a radially inwardly spaced south magnetic pole region 17 , The two areas 16 . 17 are non-rotatable via a magnetically non-conductive material (magnetic separation 18 ) connected with each other.

In the axial direction opposite from the first coupling element 6 is the second coupling element 7 with an eddy current section projecting in the axial direction 22 radially outside of this magnetic guiding means 23 in the form of, for example, pressed ring.

As is apparent from the sectional view according to 7 This results in the magnetic north pole section 16 trained north poles 19 on the same radial side as the magnetic south pole 17 trained south poles 20 , North and South poles 19 . 20 are in the embodiment shown radially within the annular eddy current section 22 and are from this across the air gap 21 spaced. North Pole 19 and south poles 20 alternate in the circumferential direction and generate when the electromagnet is energized 6 a circumferentially inhomogeneous magnetic field.

In the 8th and 9 is another alternative embodiment of an eddy current coupling 2 trained clutch 1 shown. Also this clutch 1 includes one with the help of energizers 15 energizable electromagnet 10 which is in a non-rotatable carrier component 11 held over which the of the electromagnet 10 generated electromagnetic field in a first coupling element 6 , more precisely in a magnetic north pole area 16 and a south magnetic pole region 17 can be coupled. At the magnetic north pole area 16 are a plurality of circumferentially spaced north poles 19 and to the South Pole area 17 a plurality of circumferentially spaced south poles 20 educated. Between these rotatable via air gaps 21 spaced apart is the eddy current section 22 of the second coupling element.

In the embodiment shown, the means of the electromagnet 10 loadable north poles 19 arranged radially opposite from the south poles 20 , Ie. the magnetic north poles and the south magnetic poles are not offset in the circumferential direction but are each located at the same circumferential angles.

In the circumferential direction between two each arranged in pairs (electromagnetically acted upon) north and south poles 19 . 20 There is a permanent magnet north-south pole combination. In other words, located between two circumferentially spaced electromagnetic north poles 19 one from a permanent magnet 25 educated South Pole 26 , wherein the permanent magnetic south pole of an independent permanent magnet and the associated, radially spaced permanent magnetic north pole of a separate permanent magnet (reverse orientation) are formed. In this case, the corresponding opposite poles of the permanent magnets in each case in the opposite radial direction. In the embodiment shown, the permanent magnets are realized as short, cylindrical bar magnets. It is also conceivable an alternative embodiment in which in each case a permanent magnet 25 horseshoe-like, encompassing the eddy-current section 22 on the radially inner side of the eddy current section 22 extends and there a permanent magnetic north pole 27 formed.

In this alternative variant, therefore, every combination of permanent magnetic south pole 26 and permanent magnetic north pole 27 from a common permanent magnet 25 formed, and not as in the illustrated embodiment of two separate permanent magnets.

Instead of in 9 shown radial arrangement is of course also an axial spacing analogous to the embodiment according to 3 realizable.

When the electromagnet is energized 10 the north poles form 19 and south poles 20 out, so that both radially outward and radially within the eddy current section 22 alternating north and south poles are arranged, wherein in each case between two circumferentially spaced (electromagnetic) north poles a permanent magnetic south pole or between two permanent magnetic north poles on the radially inner side of an (electromagnetic) south pole is arranged. By varying the effective energization of the electromagnet 10 can the resulting magnetic field and thus the slip between the first and second coupling element 6 . 7 to be influenced. In the embodiment shown, the slip is lowest at maximum current.

In the 10 and 11 is another alternative embodiment of an eddy current coupling 2 trained clutch 1 shown. Also this clutch 1 includes one with the help of energizers 15 energizable electromagnet 10 which is in a non-rotatable carrier component 11 held over which the of the electromagnet 10 generated electromagnetic field in a first coupling element 6 , more precisely in a magnetic north pole area 16 and a south magnetic pole region 17 can be coupled. At the magnetic north pole area 16 are a plurality of circumferentially spaced north poles 19 and a plurality of circumferentially spaced south poles 20 formed, these north and south poles in contrast to the embodiment according to the 8th and 9 not radially opposite each other or on different sides of the eddy current section 22 are arranged, but are provided alternately on a common radial side in the circumferential direction. For example only, the electromagnetic north / south poles are arranged radially inward and the permanent magnetic poles to be explained below radially outward. Alternatively, a reversed arrangement is possible. Furthermore, an exemplary embodiment is analogous to the exemplary embodiment according to FIG 3 feasible, in which the here radially spaced poles are axially spaced and the eddy current portion 22 absorb axially between them.

As it turned out 11 results, lies each electromagnetic South Pole 20 radially spaced or aligned (ie on each respective same circumferential vortex) a permanent magnetic north pole 27 opposite and every electromagnetic north pole 19 a permanent magnetic south pole 26 ,

In contrast to the embodiment according to 9 So do not change the same type, ie permanent magnetic and electromagnetic pole pairs in the circumferential direction, but the pairings are inhomogeneous insofar as that each one electromagnetic pole interacts with a permanent magnetic opposite pole or in the radial direction with this, wherein, as already explained, an axially aligned Arrangement in analogy to the embodiment according to 3 is feasible. The embodiment according to the 10 and 11 generates even in the absence of energization a pole change by the arrangement of the permanent magnets whereby even in case of failure of energization entrainment of the eddy current section 22 or the second coupling element 7 is ensured.

How out 11 can be seen, the permanent magnetic poles are formed by separate permanent magnets, the opposite poles are directed to the relevant respectively for the generation of eddy currents permanent magnetic poles in the embodiment shown radially outward.

In 12 is a clutch 1 shown in addition to an eddy current coupling 2 a friction disc clutch 28 includes. Both clutches work between the common first and second coupling elements 6 . 7 , To actuate the eddy current coupling is an electromagnet 10 provided, which is arranged rotationally fixed, so that a drive shaft 4 and a first and a second coupling element 6 . 7 are rotatable relative to this. Axially adjacent and spaced apart is a friction disc clutch solenoid 29 provided with the electromagnet 10 the eddy current coupling is arranged on a common (non-rotatable) carrier. The electromagnets 10 . 29 can be supplied separately. For this purpose, not shown Bestromungsmittel are provided, which are preferably formed by a vehicle control unit. In the embodiment shown, the energizing means, not shown, for applying the electromagnet 10 formed with a pulse width modulated current. If necessary, the friction disc clutch magnet 29 are also energized with a pulse width modulated current, in which case also an alternative current application with constant current is possible.

When the electromagnet is energized 10 with the help of the energizing means that of the electromagnet 10 generated magnetic field coupled into the first coupling element 6 namely in the plane of the drawing on the left in the axial direction and in the plane of the drawing in the middle in the radial direction, in which case there is a magnetic north pole region 16 and a magnetic south pole area 17 form.

North Pole area 16 and South Pole area 17 are separated by a magnetic separation to avoid a magnetic short circuit and rotatably connected. Preference is given to the north pole area and the south pole area 16 . 17 in the axial direction toothed into each other. It is therefore preferred in the circumferential direction next to each other alternately north poles and south poles - in other words, results in an arrangement of circumferentially alternately arranged north and south poles for generating a inhomogeneous magnetic field in the circumferential direction.

In the radial direction over an air gap 21 from the north and south poles 16 . 17 separated and in the radial direction opposite and spaced apart is an annular eddy current portion 22 in the form of an annular electrical conductor, for example made of copper, arranged in the case of a relative movement of the first and second coupling element 6 . 7 eddy currents are induced to each other.

On the side of the eddy current section facing away from the north and south poles 22 are Magnetleitmittel 23 in the form of a return ring, which is the magnetic field in the eddy current section 22 focus.

With rotating first coupling element 6 induce the magnetic fields of the electromagnet 10 in the eddy current section 22 Eddy currents. These eddy currents in turn generate a magnetic field that matches the magnetic field of the electromagnet 10 enters an interaction and counteracts this magnetic field so that the second coupling element by the rotation of the first coupling element 6 also in a rotation in the same circumferential direction offset (entrained) is.

By varying the duty cycle of the PWM current, the effective current (effective magnetic field relevant current) and thus the strength of the magnetic field formed by the electromagnet between the north and south poles can be influenced and thus again the slip between the first, directly from the drive shaft 4 driven coupling element 6 and the entrained second coupling element 7 , which in the embodiment shown, the output of the clutch 1 forms, on which here the accessory 5 is fixed immediately.

To the torque lossless, ie without slip, from the output shaft 4 or the first coupling element 6 on the second coupling element 7 to transfer, is the aforementioned friction disc clutch 28 intended. This includes the Reibscheibenkupplungsmagneten 29 with which a friction disc 30 is axially adjustable, via a return spring 31 to the second coupling element 7 is connected. It can be seen that in a radial arm 32 (Radial disc) a circumferentially extending magnetic separation 33 is integrated, which separates a radially outer portion of a radially inner portion. This magnetic separation 33 is necessary to energize the Reibscheibenkupplungsmagneten 29 the magnetic flux across the working air gap 34 to force, which extends in the circumferential direction and in the radial direction and not energized Reibscheibenkupplungsmagneten 29 the radial arm 32 of the first coupling element 6 axially spaced from that on the second coupling element 7 fixed (here axially) by means of the friction disc clutch magnet 29 adjustable friction disc 30 , Will the electromagnet 29 so energized, the magnetic flux in the radially upper portion and the radially lower portion of the coupling element 6 coupled in the illustrated embodiment via a extending in the axial direction gap between the carrier of the friction disc clutch magnet 29 and a (lower) or inner axial extension of the first coupling element. In this, the magnetic flux passes over the working air gap 34 into the friction disk 30 , in this in the radial outward direction, then axially back into the radially outer portion of the coupling element 6 , there in the axial direction and then bridges the radial gap between the upper portion of the coupling element 6 and the carrier of the friction disc clutch magnet 29 in the radial direction. The electromagnets 10 . 29 are poled so that they do not block in their effect - ie the South Pole area 17 the eddy current coupling 2 is at the same time the South Pole area of the friction disc clutch. The north pole region of the friction disc clutch is from the radially lower portion of the radial arm 32 educated.

It can be seen that between the electromagnet 10 and the friction disc clutch electromagnet 29 common magnetic means 35 are provided by which both the magnetic flux of the electromagnet 10 as well as the magnetic flux of the friction disc clutch electromagnet 29 can flow in the radial direction.

The embodiment according to 13 differs from the embodiment according to 12 only by the arrangement of the electromagnet 10 and the friction disc clutch electromagnet 29 , which are radially spaced here and spaced from each other via common Magnetleitmittel 35 for conducting the magnetic flux here in the axial direction. The friction disc clutch 28 otherwise has an almost identical structure. You can also see the magnetic separation 33 in the radial arm 32 as well as on the second coupling element 7 fixed friction disc 30 , with which the first coupling element 6 torque transmitting, slip-free coupling with the second coupling element can be coupled and that during energization of the friction disc clutch element 29 ,

Also, the structure of the eddy current coupling 2 corresponds essentially to the structure according to the embodiment according to FIG 12 , There are provided in the circumferential direction alternating north and south poles, which - with not coupled friction disc clutch 28 - Relative to the second coupling element 7 More specifically, to the eddy current section 22 , can rotate.

In the embodiment according to 14 are also a friction disc clutch 28 and an eddy current clutch 2 in a common clutch 1 realized, in which case in contrast to the embodiment according to the 12 and 13 a common electromagnet 10 is provided for the friction disc clutch 28 and the eddy current coupling 2 , In other words, the electromagnet forms 10 at the same time the friction disc clutch magnet 29 , The magnetic flux proceeds from the electromagnet 10 or its rotatably arranged carrier by the eddy current coupling 2 and through the friction disc clutch 28 and bridges there in not switched state of the friction disc 30 the working air gap 34 , With sufficiently large effective energizing the friction disc 30 operated and thus the eddy current coupling 2 bridged, ie, the torque is immediately without slip from the output shaft and thus rotatably arranged first coupling element on the second coupling element 7 and thus on the accessory 5 transfer.

Basically, variations of the embodiments according to the 12 to 14 possible - so the eddy current coupling and in particular their north and south pole regions or in turn their arrangement relative to the eddy current portion can also be formed analogously to the preceding embodiments.

The following are based on the 15 to 20 different structural design options of the various embodiments according to the 12 to 14 described.

In 15 is the upper half of a clutch 1 in a motor vehicle for operating a here designed as a fan accessory 5 shown, which rotatably with a second coupling element 7 connected is. The coupling 1 includes in addition to a slip variable eddy current coupling 2 a friction disc clutch 28 , As it turned out 15 results, is rotatably with a drive shaft, a first coupling element 6 connected, which is a radial arm 22 (Radial disc section), with magnetic separations 33 is provided.

The first coupling element 6 surrounds a rotatably mounted carrier 36 who has a rolling bearing 37 is mounted on the rotatably arranged drive shaft.

The second coupling element 7 is about another rolling bearing 38 axially spaced from the rolling bearing 37 relative to the drive axle 4 rotatably mounted.

It can be seen that two electromagnets are arranged in the carrier, namely an electromagnet 10 the eddy current coupling 2 as well as a friction disc clutch electromagnet 29 ,

Firm with the second coupling element 7 is a friction disk 30 connected to the coupling element 7 over as return spring 31 trained return means is established, which ensure that when switching off the Reibscheibenkupplungselektromagneten 29 the friction disc clutch 28 is decoupled. For engaging the friction disc clutch 28 becomes the friction disc electromagnet 29 energized. This results in a magnetic flux 39 , which is indicated by a large dashed line. The magnetic flux 39 flows through radial magnetic means 35 of the carrier 36 in an axial extension of the carrier and from this in the radial direction over a circumferential gap 40 in a friction disc clutch north pole area 41 of the first coupling element 6 , This friction disc clutch north pole area 41 is about the magnetic separations 33 magnetically decoupled from the magnetic south pole region 17 the eddy current coupling, this south pole region 17 , at least in one of the friction discs 30 opposite region, also the south pole region of the friction disc clutch 28 represents. The magnetic flux 39 crosses the working air gap several times in the embodiment shown 34 and then flows over the South Pole area 17 again radially inward into a radially outer axial extension of the carrier 36 ,

For actuating the eddy current coupling 2 is the electromagnet 10 intended.

It can be seen that the magnetic south pole area 17 and the magnetic north pole area 16 the friction disc clutch 2 via a non-magnetically conductive connecting part 42 rotatably coupled to each other. Overall, results in the embodiment according to the 15 and 16 As a result, an alternating arrangement of circumferentially alternately arranged north and south poles, which are arranged relatively rotatable to a radially spaced eddy current section 22 with radially outwardly arranged Magnetleitmittel 23 of the second coupling element 7 ,

It can be seen in the 15 and 16 the magnetic flux 43 , which consists of the pulse width modulated current supply of the electromagnet 10 results.

In the 17 and 18 is an alternative embodiment of a clutch 1 comprising a variable eddy current coupling 2 and a friction disc clutch 28 for switching through the torque of the drive shaft to the output or the auxiliary unit 5 shown. In contrast to the preceding embodiments, the carrier has 36 for the electromagnet 10 and the friction disc clutch magnet 29 a greater radial than axial extension. The electromagnet 10 is located radially outside of the friction disc clutch electromagnet 29 , The two magnets 10 . 29 are spaced apart by common magnetic conduction means 35 ,

The second coupling element 7 carries a friction disk 30 axially opposed to a radial arm 32 of the first coupling element 6 , in which in a radially outer region, such as 18 it can be seen, North Pole 19 and south poles 20 the eddy current coupling 2 are formed, which are arranged alternately in the concrete embodiment in the radial direction.

It can be seen in 17 in particular, the connecting part 42 of a non-magnetically conductive material, which is the magnetic north pole region 16 the eddy current coupling 2 rotatable with the magnetic South Pole area 17 combines.

In the 19 and 20 is a particularly preferred embodiment of a coupling 1 comprising an eddy current coupling 2 and a friction disc clutch 28 shown, wherein here only a single (common) magnet for actuating both clutches 2 . 28 is provided. In a lower power supply, the eddy current coupling 2 variable, ie with variable slip, are operated, whereas when a limit energization or minimum energization is exceeded, the friction disc clutch 28 is switched. In the embodiments described above, the friction disc clutch 28 switched on when a certain current is exceeded - of course, the alternative embodiment can be realized in which opens the friction disc clutch falls below a predetermined energization.

The components that are tightened to the right are magnetic flux conducting (magnetically conductive), whereas the left-toned components are not magnetically conductive.

The common electromagnet 10 . 29 is in a carrier 36 held, which is arranged rotationally fixed, wherein the drive shaft 4 relative to the carrier 36 rotates. For this purpose the bearing is 37 provided in analogy to the preceding embodiments. The first coupling element 6 is rotatably coupled to the drive shaft 4 whereas the second coupling element 7 over the rolling bearing 38 opposite the drive shaft 4 rotatably mounted.

As it turned out 20 in synopsis with 19 results are by energizing the electromagnet 10 a north pole area 16 and a south pole area 17 with alternately arranged north and south poles 19 . 20 shown relative to an eddy current section 22 of the second coupling element 7 are rotatably arranged. The magnetic flux 39 of the electromagnet 10 bridges both the working air gap 34 the friction disc clutch, so flows from the first coupling element 6 into the friction disk 30 and back again and also penetrates the circumferential gap between the first coupling element 6 and second coupling element 7 in the field of eddy current coupling 2 ,

LIST OF REFERENCE NUMBERS

1

clutch

2

Eddy current clutch

3

internal combustion engine

4

drive shaft

5

accessory

6

first coupling element

7

second coupling element

8th

camp

9

magnet means

10

electromagnet

11

support component

12

camp

13

gap

14

energizing

15

energizing

16

magnetic north pole area

17

magnetic south pole area

18

magnetic separation

19

North Pole

20

South Pole

21

Air gap (e)

22

Eddy current section

23

Magnetleitmittel

24

radial gap

25

Permanent magnet (s)

26

permanent magnetic south pole

27

permanent magnetic north pole

28

friction disc clutch

29

Reibscheibenkupplungsmagnet

30

friction

31

Return spring

32

radial arm

33

magnetic separation

34

Working air gap

35

Magnetleitmittel

36

carrier

37

roller bearing

38

roller bearing

39

magnetic flux

40

circumferential gap

41

Reibscheibenkupplungsnordpol

42

Connecting part (magnetic separation)

43

magnetic flux

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 0634568 A1 [0002]

Claims (15)

Coupling, in particular for transmitting a torque from one of an internal combustion engine ( 3 ) driven drive shaft ( 4 ) on an accessory ( 5 ) of a motor vehicle, preferably on an internal combustion engine fan, comprising an eddy current coupling ( 2 ) with a first rotatable coupling element ( 6 ) comprising an electrically conductive eddy current section ( 22 ), in which eddy currents can be formed and with a second coupling element ( 7 ), which of the first coupling element ( 6 ) via an air gap ( 21 ) is separated and relative to the first coupling element ( 6 ) is rotatable and the magnetic means ( 9 ) are assigned such that in a relative rotation of the first and the second coupling element ( 6 . 7 ) to each other in the eddy current section ( 22 ) Eddy currents are generated, so that one of a drive shaft ( 4 ) driven the coupling elements ( 6 . 7 ) the other of the coupling elements ( 6 . 7 ) entrains in the circumferential direction, characterized in that the magnetic means ( 9 ) at least one electromagnet ( 10 ), the energizing agent ( 14 . 15 ) are assigned, with which the effective energization of the electromagnet ( 10 ) for varying the slip between the first and the second coupling element ( 6 . 7 ) is adjustable. Coupling according to claim 1, characterized in that the, preferably by a motor vehicle control unit formed, energizing means ( 14 . 15 ) for applying the magnetic means ( 9 ) are formed with a modulated current, in particular a PWM current. Coupling according to one of claims 1 or 2, characterized in that the electromagnet ( 10 ) rotationally fixed with respect to the drive shaft ( 4 ) of the eddy current coupling ( 2 ) and is arranged relative to the first coupling means such that one of the magnetic means ( 9 ) generated magnetic flux in the second coupling element ( 7 ) can be coupled. Coupling according to one of the preceding claims, characterized in that with the electromagnet ( 10 ) in the first coupling element ( 6 ) a magnetic north pole region ( 16 ) and a magnetically connected therewith and magnetically separated from this south magnetic pole region ( 17 ) is producible. Coupling according to claim 4, characterized in that the north pole region ( 16 ) a plurality of circumferentially arranged north poles ( 19 ) and the South Pole area ( 17 ) a plurality of circumferentially arranged south poles ( 20 ) having. Coupling according to claim 5, characterized in that the north pole ( 19 ) and the south poles ( 20 ) are arranged relative to one another in such a way that they are preferably intermeshing with one another in the circumferential direction and / or in the manner of a toothing, that during a relative movement between the first and the second coupling element ( 6 . 7 ) in the circumferential direction, the magnetic field in the eddy current section ( 22 ) changes. Coupling according to one of claims 4 to 6, characterized in that the north pole region ( 16 ) and the South Pole area ( 17 ), in particular the North Pole ( 19 ) and the south poles ( 20 ) on a common radial or a common axial side of the eddy current section (FIG. 22 ) are arranged. Coupling according to claim 7, characterized in that on the north and south poles ( 19 . 20 ) facing away from the eddy current section ( 22 ) Magnetic Conductor ( 23 ) are provided. Coupling according to one of claims 6 or 7, characterized in that the north pole ( 19 ) and the south poles ( 20 ) on different radial or axial sides of the eddy current section (FIG. 22 ) are arranged. Coupling according to one of the preceding claims, characterized in that the magnetic means ( 9 ) in addition to the electromagnet ( 10 ) at least one, preferably a plurality of permanent magnets ( 25 ), and that the at least one electromagnet ( 10 ) in such a way by means of the energizing means ( 14 . 15 ) is energized, that from the at least one permanent magnet ( 25 ) and the at least one electromagnet ( 10 ) is stronger or weaker than that of the at least one permanent magnet ( 25 ) resulting magnetic field. Coupling according to one of the preceding claims, characterized in that the coupling ( 1 ) as a multi-stage coupling ( 1 ) is formed and next to the eddy current coupling ( 2 ) at least one further coupling ( 1 ), in particular a friction disc clutch ( 28 ). Coupling according to claim 11, characterized in that the friction disc clutch ( 28 ) with the electromagnet ( 10 ) of the eddy current coupling ( 2 ) is switchable, in particular by maximum energization of the electromagnet ( 10 ), and / or that the friction disc clutch ( 28 ) a friction disc clutch electromagnet ( 29 ) assigned. Coupling according to claim 12, characterized in that the electromagnet ( 10 ) of the eddy current coupling ( 2 ) and the friction disc clutch electromagnet ( 29 ) axially with respect to Drive shaft ( 4 ) are arranged one behind the other, in particular with magnetic conducting means ( 35 ) for radially guiding the magnetic flux of the electromagnet ( 10 ) and the friction disc clutch electromagnet ( 29 ). Coupling according to claim 12, characterized in that the electromagnet ( 10 ) of the eddy current coupling ( 2 ) and the friction disc clutch electromagnet ( 29 ) radially with respect to the drive shaft ( 4 ) are arranged one behind the other, in particular with a magnetic guide means ( 35 ) for axially guiding the magnetic flux of the electromagnet ( 10 ) and the friction disc clutch electromagnet ( 29 ). Coupling according to one of claims 11 to 14, characterized in that by means of the friction disc clutch ( 28 ) the first and the second coupling element ( 6 . 7 ) are rotatably coupled to each other, wherein preferably one, in particular axially, adjustable friction disc ( 30 ) of the friction disc clutch ( 28 ) to that of the coupling elements ( 6 . 7 ) is arranged, on which also the eddy current section ( 22 ) of the eddy current coupling ( 2 ) is arranged.

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