DE102013002987A1 - Freewheel device for coupling crankshaft in gear unit of vehicle engine, has clamping element that is moved into coupling position from release position due to force and magnetic flux on clamping element by electromagnetic device - Google Patents

Abstract

The freewheel device (8) has a clamping element which is arranged between two coupling components and switched between the release position and coupling position. An electromagnetic device is provided to actuate the clamping element. The clamping element is moved into coupling position from release position by the force and magnetic flux acting on the clamping element. The clamping element is made of ferromagnetic material. An independent claim is included for a method for selective connecting of two coupling components.

Description

The present invention relates to a freewheel device for selectively connecting two coupling partners with at least one clamping body which is arranged between the two coupling partners and can be transferred from a freewheeling position into a coupling position. Furthermore, the present invention relates to a transmission unit with a corresponding freewheel device and to a method for selectively connecting two coupling partners by means of such a freewheel device.

Freewheel devices for selectively connecting two clutch partners are required in modern motor vehicles in order to realize different operating states of the internal combustion engine. In order to reduce fuel consumption and the associated emission of pollutants, the internal combustion engine is switched off in modern motor vehicles when the vehicle no longer has to be actively driven, but can drive without power. Such an operating state can occur in motor vehicles, for example, when driving onto a red traffic light or when driving on a downgrade. This operating state without an active drive of the motor vehicle by the internal combustion engine is referred to as sailing operation. The sailing operation also requires a start-stop function for the internal combustion engine to restart and use the internal combustion engine without delay when changing the operating situation. The sailing operation and also the required start-stop function require an independent of the engine to be operated auxiliary drive, which can be driven without a drive through the engine to sufficiently drive the necessary for the operation of the vehicle ancillaries in sailing operation.

The secondary engine of an internal combustion engine drives the auxiliary units required for the operation and function of the motor vehicle by means of a coupling with the internal combustion engine and supplies the vehicle with electrical energy via a generator. In order to enable a sailing operation in modern motor vehicles, a freewheel device must be integrated in the drive train between the engine and the auxiliary drive, the drive of the ancillaries in a sailing operation by means of an integrated electric drive in the auxiliary drive and in the coupled state, the drive of the ancillaries of the internal combustion engine permits. In this case, the freewheel device is usually positioned at the connection point between the crankshaft of the internal combustion engine and the crankshaft drive wheel of the secondary drive or in the crankshaft drive wheel itself. In addition, there are just in the entire drivetrain of modern motor vehicles other uses for freewheel devices for selectively connecting two coupling partners.

In the powertrain of modern motor vehicles and hybrid vehicles very different constructions for the technical realization of freewheel devices for selectively connecting two coupling partners are known. Such usually trained as sprag or pinch roller freewheels couplings allow when the load conditions change, one coupling partner from the rotational movement of the other to decouple, or selectively connect to the other. From the publication DE 39 11 075 A1 For example, a powershift freewheel clutch device for four-wheel motor vehicles is known in which a variable diameter clamping ring causes a coupling of the coupling partner by utilizing a wedge surface effect by the relative rotation of a provided with clamping bodies switching part for diameter variable clamping ring. Furthermore, from the DE 103 27 213 A1 a sprag freewheel device for coupling two coupling partners in both directions of rotation, in which the clamp bodies arranged between the clamping bodies have an inner and an outer clamping contour, so that when the clamping body is tilted, a clamping of the coupling partner in both directions of rotation is possible. The center of gravity of the prestressed by at least one spring clamping body is arranged eccentrically, so that the centrifugal force causes tilting of the clamping body against the spring force to connect the coupling partners together. Many of the freewheel devices known in the prior art have proven themselves well even in use in motor vehicles, with just the mechanical circuit of the freewheel devices via the centrifugal forces acting on the clamping body and the load change between the two coupling partners allows a contactless control of the freewheel devices. In this case, friction losses between the clamping bodies and the clutch partner moving relative to one another occur not only in the case of simply designed sprag-type freewheel devices in the non-coupled state.

Although many of the prior art constructions for overrunning devices having at least one sprag have proven to be well suited for use in motor vehicles, there is a continuing effort to improve the constructions of components and to adapt to the increasing demands of the general innovation pressure in the automotive industry.

The present invention is therefore an object of the invention to provide a freewheel device for selectively connecting two coupling partners, which enables a safe switching between the various operating conditions and at the same time economical operation with a simple construction possible.

This object is achieved in that an electromagnetic means for actuating the at least one clamping body is provided, which transfers the at least one clamping body of the freewheeling position into the coupling position by means of acting on the at least one clamping body magnetic flux. Novel combinations of mechanical and electronic components in a freewheel device for selectively connecting two coupling partners allows not only a structurally simple construction but also a simple and dynamic actuation. The electromagnetic actuation of the clamping body is independent of a force acting on the clamping body centrifugal force and thus also independent of the movement of the coupling partner. In addition, an active electromagnetic actuation of the freewheel device allows a much faster coupling of the coupling partners in comparison to conventional freewheels exploiting the inertia of the clamping body. In the freewheeling position, the coupling partners are completely independently movable, while in the coupling position, the coupling partners are coupled together and only moved together. As a result of the electromagnetic actuation of the clamping body by means of the electromagnetic device, usually an electrical coil, the at least one clamping body arranged on one of the coupling partners is transferred from a substantially friction-free freewheeling position into the coupling position in order to temporarily establish a coupling with the second coupling partner. Even if the present electromagnetic actuated freewheel device only requires a clamping body, it is preferably possible to use a plurality of clamping bodies which are arranged uniformly between the two coupling partners. In this case, the at least one clamping body as a mechanical part of the freewheel device is at the same time also part of the magnetic circuit through which the magnetic flux flows upon activation of the electromagnetic device. For as vibration-free and problem-free coupling of the two coupling partners they can be synchronized in their movement before activation of the at least one clamping body.

Suitably, the at least one clamping body may be made at least in part of a magnetizable material, preferably of a ferromagnetic material, in particular offering soft magnetic materials that can be easily magnetized in a magnetic field. The at least partial formation of the clamping body of a magnetizable material ensures the good and effective integration of the clamping body in the magnetic flux during the actuation by the electromagnetic device. In addition to the simple production of the clamping body, the formation of a magnetizable material allows different functional design, wherein in addition to a formation of a core or an outer part of the clamp body from extending in the longitudinal direction of the clamping body magnetizable material, the clamping body in particular also made entirely of a magnetizable or ferromagnetic material could be.

An advantageous embodiment provides that the at least one clamping body is designed to be self-holding in the coupling position. The electrical actuation of the at least one clamping body by the electromagnetic device acts as an impulse on the clamping body and causes a coupling of the two coupling partners. In the coupling position, the at least one clamping body is then held independently of the electromagnetic device by means of the possible after the selective connection torque transmission between the two coupling partners. Since the torque transmission between the two coupling partners holds the at least one clamping body after a transfer to the coupling position without permanent actuation by the electromagnetic device in the coupling position, no continuous power supply for activating the electromagnetic device is necessary in the switching period. Due to the self-holding configuration of the at least one clamping body, only a small activation energy is required for selectively connecting the two coupling partners of the freewheel device, which leads to a significant energy saving compared to conventional actively activated freewheel devices with the inherent coupling of the coupling partners in the switching period by means of torque transmission.

For a simple construction of the freewheel device according to the invention, the at least one clamping body can be arranged pivotably on one of the two coupling partners and can be in frictional contact or positive-locking contact with the other two coupling partners in the coupling position. The pivotal arrangement of the at least one clamping body allows the latter, in a relatively simple interaction with the magnetic flux of the electromagnetic device acting on it, to pivot into a more upright position oriented in the direction of the magnetic flux by simply rising from an inclined position to the magnetic flux. The erection of the Clamping body at an actuation by the electromagnetic device leads to a reduction of the resistance to the magnetic flux and correspondingly in the associated magnetic circuit.

Preferably, a return device may be provided which holds the at least one clamping body in the freewheeling position and / or transferred from the coupling position to the freewheeling position. By means of the return device, the at least one clamping body is securely held in its free-running position on one of the two coupling partners, whereby a freewheeling gap is set relative to the other coupling partner. This means that the two coupling partners can be moved independently of one another without friction, which reduces the overall mechanical resistance of the freewheel device. Accordingly, the freewheel device in the freewheeling position may have a freewheeling gap between the first coupling partner with the at least one clamping body and the second coupling partner of only 0.1 to 1.5 mm, preferably of 0.3 to 1.0 mm. When returning the at least one clamp body from the coupling position, in which the clamp body is held by the torque transmitted between the two coupling partners, the restoring device pulls or pushes the clamp body back into its free-running position after terminating the torque transmission. In the design of the spring force of the return device is in addition to the clamping or wedge effect with a low torque transmission between the two clutch partners, which must be greater than the spring force, and the clamping or wedge effect without a torque transmission, which must be smaller than the spring force, Also, the force of the magnetic flux for moving the at least one clamping body in the coupling position and for bridging the freewheeling gap, which must be greater than the spring force of the return device to take into account.

A favorable embodiment provides that the two coupling partners are designed for transmitting torque in two directions of rotation, wherein the two coupling partners are selectively connected by means of the at least one clamping body in the coupling position in one direction of rotation or in the other direction. Such a bidirectional freewheel device allows a transmission of torque between the two clutch partners in both directions without providing an additional mechanical component for this purpose. Bidirectional freewheel devices are needed in particular in modern motor vehicles and hybrid vehicles. To simplify the function of the bidirectionally acting freewheel device, a plurality of clamping bodies may be provided, which are designed selectively for one of the directions of rotation and can therefore be constructed in a structurally simple manner.

To simplify the structural design of the freewheel device and to reduce the mechanical and electrical resistance in the freewheel device, the electromagnetic device may be arranged independently of the two clutch partners, in particular fixedly opposite to the two torque-transmitting movable coupling partners arranged. The independent, preferably fixed arrangement of the electromagnetic device is a direct, independent supply of electrical energy possible. The avoidance of sliding contacts for energy transfer or the avoidance of an inductive contactless energy transfer device not only allows a simple and inexpensive construction of the freewheel device, but also reduces the wear and the loss of energy not only in the freewheel device by avoiding mechanical and / or electrical resistance of such energy transfer devices. In this case, in a simple variant, the electromagnetic device may be designed as an electrical coil, which generates a magnetic flux via the clamping body during a current flow through the coil.

A further embodiment of the freewheel device provides that the two coupling partners are arranged concentrically with one another, and a plurality of clamping bodies are provided between the two coupling partners, wherein the clamping bodies are arranged in the freewheeling position on the inner first coupling partner with a freewheeling gap to the outer second coupling partner, and wherein the clamping body in the coupling position in a frictional contact or form-fitting contact to the outer second coupling partner to selectively connect the two coupling partners together. The concentric arrangement of the two coupling partners and thus the radial alignment of the torque transmission via the freewheel device is a common application, especially in the field of motor vehicles. The radial arrangement of the coupling partners relative to their axis of rotation in an arrangement of the clamping body on the inner coupling partner supports the transfer of the clamping body from the freewheeling position to the coupling position by the centrifugal forces acting on the clamping body during a rotational movement of the inner first coupling partner. The provision of a plurality of clamping body and thereby possible uniform arrangement of the clamping body on the radially encircling first inner coupling partner avoids the provision of balancing weights and reduces the risk of imbalance of the first coupling partner. Appropriately, in such a radial freewheel device, the clamping body and the associated contact path of the second clutch partner designed as a friction partner, which form a frictional connection in a contact and a torque transmission between the two clutch partners.

For a quick and reliable radial erection of the clamp body in the coupling position, the clamp body can be kidney-shaped, the kidney-shaped clamp body are preferably arranged in blocks on the inner first coupling partner and each block is assigned to one of the two directions of rotation of the coupling partner. The kidney-shaped design of the clamping body allows a direct juxtaposition of several clamping body, without adversely affecting their pivotal movement for transfer to the coupling position. By such a block-wise arrangement of adjoining and uniformly moving clamping body allows the provision of very many clamping body on a relatively small area, so that the frictional force of a corresponding frictional connection is increased. Since the kidney-shaped clamping body are all constructed identical, there are no increased manufacturing and assembly costs. In addition, these kidney-shaped clamping body can be arranged in a simple manner uniformly on the inner first coupling partner and distributed accordingly for a bidirectional effect of the freewheel device. An advantage is further that the kidney-shaped clamping body perform a pivoting movement when transferring the freewheeling position in the coupling position. The pivoting movement of the kidney-shaped clamping body allows in particular in the blockwise arrangement and a common erection of the clamping body, but also after an end of the torque transmission between the two coupling partners a safe and easy solution of the clamping body from the coupling position and the return to the freewheeling position.

A particular embodiment provides that the inner first coupling partner is formed with a plurality of convex receiving pockets, in which the clamping body are at least partially accommodated. Such a relatively simple construction of the inner first coupling partner enables a variable and at the same time secure arrangement of the clamping bodies, without influencing their actuation by the magnetic flux generated by the electromagnetic device. In this case, the convex receiving pockets for receiving the preferably kidney-shaped clamping body may conveniently have a semicircular profile.

A variant of the freewheel device according to the invention provides that a spring element is provided as a restoring device which holds the clamping body in the freewheeling position on the inner first coupling partner with a freewheeling gap to the outer second coupling partner and / or the clamping body of the coupling position in the freewheeling position on the inner transferred first coupling partner. A spring element is a cost-effective and easy to implement solution for a restoring device of the clamping body in the freewheel device, in particular as a circumferential elastic ring. It can be very evenly create a spring action on all positioned on the inner first coupling partner clamp body with a circumferential elastic ring. In order to bring the spring element, in particular as a circumferential elastic ring in a simple manner with the clamping bodies in operative function, the clamping body may be provided with a groove in which the spring element is arranged. Such a particular semicircular groove can be considered very easily in the production of the clamping body, and avoids influencing the coupling function of the clamping body with the second outer coupling partner, especially in a preferred frictional connection between the clamping bodies and the second coupling partner.

The present invention further relates to a transmission unit, in particular for coupling a crankshaft of an internal combustion engine by means of a switchable planetary gear with an electric machine arranged in a secondary operation, with one of the above-defined free-wheeling devices according to the invention. In modern motor vehicles, whether with a fuel-efficient combustion engine or with a hybrid drive, the aspects of optimizing energy consumption and reducing pollutant emissions are nowadays very important design aspects. Accordingly, this also applies to all transmission units for selectively connecting clutch partners, no matter whether for coupling a crankshaft of an internal combustion engine with an electrical machine arranged in a secondary operation or for connecting the drive train or individual drive units to the wheel hub, and integrated therein freewheel devices according to the present invention ,

Furthermore, the invention also relates to a method for selectively connecting two coupling partners of a freewheel device with at least one clamping body and an electromagnetic device for actuating the at least one clamping body with the steps:
Generating a magnetic field by the electromagnetic device, wherein the at least one clamping body is arranged in the magnetic field;
Erecting the at least one clamping body from the freewheeling position to the coupling position for Bridging the freewheeling gap between the two coupling partners;
Coupling the two coupling partners through the at least one clamping body;
Transmitting a torque between the two clutch partners;
Self-locking of the at least one clamping body in the coupling position by means of torque transmission between the two coupling partners; and
Switching off the magnetic field.

In contrast to the function of known freewheels for selectively connecting two coupling partners, no centrifugal forces acting on the at least one clamping body are required here, but merely the activation energy of an electromagnetic device. Instead, only a magnetic circuit generated by the magnetic flux of the electromagnetic device is required here via the at least one clamping body in order to bring about a transfer from the freewheeling position to the coupling position. In this case, the clamping body is part of the magnetic circuit, which moves to reduce the resistance in the magnetic circuit in the coupling position. Since this method requires only the activation of the electromagnetic device for actuating the clamping body electrical energy and in the freewheeling position of the clamping body by the freewheeling gap allows a frictionless rotation of the two coupling partners, this method leads in contrast to the function of known freewheels to an energy saving.

In the following, an embodiment of the present invention will be explained in more detail with reference to drawings. Show it:

1 a schematic representation of a connected to the crankshaft slave drive of an internal combustion engine;

2 a perspective view of a freewheel device according to the invention, integrated in a crankshaft Nebenbiebsrad;

3 a radial section through the freewheel device according to the invention 2 ;

4 an enlarged detail view of the clamping body from the radial sectional drawing of the freewheel device according to the invention 3 ;

5 a perspective assembly drawing of the freewheel device according to the invention 2 ;

6 an axial section through the freewheel device according to the invention 2 ;

7 a perspective view of the axial section through the freewheel device according to the invention 6 ;

8th an enlarged detail view of the clamping body from the perspective view of the freewheel device according to the invention 7 ; and

9 an enlarged detail view of the freewheel device according to the invention 6 ,

1 shows the by-drive 1 an internal combustion engine, in particular for use in an energy-saving motor vehicle or a hybrid vehicle, via a secondary drive crankshaft 2 and the crankshaft 3 is connected to the internal combustion engine (not shown). To selectively connect this slave drive 1 with the internal combustion engine is between the crankshaft 3 the internal combustion engine and the crankshaft secondary wheel 2 a freewheel device according to the invention 8th intended. In the by-drive 1 Further, an electric machine (not shown) is provided, which via the drive wheel 4 in the secondary drive 1 is coupled. In addition, in this secondary drive 1 at least one auxiliary unit of the internal combustion engine, for example a brake booster, a hydraulic pump or an air conditioning unit, provided by a drive wheel 5 in the secondary drive 1 is involved. The drive wheel 4 the electric machine and the drive wheel 5 the at least one auxiliary unit are on the rotating drive means 6 of the by-drive 1 , usually a belt, with the crankshaft by-drive wheel 2 positively connected with each other. In addition to the usual training of the secondary drive 1 as a belt drive without training also training as a chain drive with a rotating drive chain is possible. To get a good power transfer from the crankshaft secondary wheel 2 on the drive wheel 4 and the drive wheel 5 to make sure, are in the secondary drive 1 two tension rollers 7 provided that the revolving drive means 6 pretension accordingly.

If, during sailing operation of the motor vehicle, for example when driving on a red traffic light or driving on a downgrade, the internal combustion engine to reduce fuel consumption and pollutant emissions is switched off, the drive of the slave drive takes place 1 over the drive wheel 4 by means of the electric machine in order to sufficiently drive the necessary for the operation of the vehicle ancillaries. Here is the crankshaft-side drive wheel 2 by a freewheel device according to the invention 8th from the crankshaft 3 decoupled. In an operation of the internal combustion engine, the freewheel device according to the invention is 8th activated and over the Torque transmission between the crankshaft 3 and the crankshaft secondary wheel 2 inherently coupled, so over the secondary drive 1 and the drive wheel 4 a rotary motion is transmitted to the electric machine. In this operating state, the electric machine then no longer acts as a drive but as a generator in order to refill a connected energy store and to supply the electrical system of the motor vehicle with electricity. This operating state is therefore also referred to as a generator mode.

The crankshaft secondary wheel 2 out 1 is in 2 shown in an enlarged perspective view, wherein the freewheel device according to the invention 8th radially between the crankshaft secondary wheel 2 and the crankshaft 3 is arranged. Here are the clamp body 9 on the inner ring 11 the first inner clutch partner arranged with the crankshaft 3 connected is. The clamp body 9 are formed as elongated in cross-section kidney-shaped elements on the outer ring 12 facing front or friction side have a frictional contact surface around with the outer ring 12 the second outer clutch partner can be in frictional connection. The outer ring 12 is as part of the second clutch partner with the pulley ring 13 connected, the rotational movement of the crankshaft 3 over the selectively with the outer ring 12 related clamp body 9 on the drive means 6 of the by-drive 1 transfers. To reset the clamp body 9 from the coupling position in which the clamping body 9 in frictional contact with the outer ring 12 stand, in the freewheel position, in which there is a freewheeling gap 32 between the clamp body 9 and the outer ring 12 Adjust is via the clamp body 9 a circumferential elastic spring ring 14 strained, the appropriate spring force for the provision of the clamping body 9 applies. For the transfer of the clamping body 9 from the freewheel position to the clutch position is part of the freewheel device 8th an electromagnetic device 15 provided by means of a magnetic flux through the clamping body 9 an erection of the kidney-shaped clamp body 9 and thereby a frictional contact with the outer ring 12 causes.

The interaction of the inner ring 11 the first inner clutch partner arranged clamping body 9 with the outer ring 12 of the second outer coupling partner is clearly in the radial section through the freewheel device according to the invention 8th in 3 to recognize. The inner ring 11 turns together with the crankshaft 3 and the block bidirectional on the inner ring 11 arranged clamping bodies 9 , At an actuation of the clamp body 9 through the electromagnetic device 15 by means of the electromagnetic device 15 generated magnetic flux through the clamp body 9 All clamp bodies are aimed 9 from a position slightly inclined with respect to the magnetic flux, to a more upright position to engage the outer ring 12 to come into frictional contact. Instead of a corresponding training of the clamping bodies 9 facing Reibkontaktfläche 16 of the outer ring 12 and the corresponding end faces of the clamping body 9 as a rubbing side 18 For a frictional contact these contact areas can also be provided with a corresponding contour for a form-locking contact.

Like both in 3 as well as in the enlarged detail view of the clamp body in 4 To recognize, are the kidney-shaped clamp body 9 Blockwise on the inner ring 11 arranged. In each case, 6 of the kidney-shaped clamping body in the same direction of inclination, spoon-like and arranged touching each other. Subsequent to such a block in one direction inclined clamping body 9 are after a short space the next six kidney-shaped clamp body 9 in the other direction inclined on the inner ring 11 positioned. For the arrangement of the clamping body 9 are on the inner ring 11 convex pockets 17 provided according to the friction side 18 the clamp body 9 opposite end face 19 are formed. To simplify the contour of the convex receiving pockets 17 is the shape of the front side 19 uniformly shaped, in particular formed with a same radius, and so regardless of the inclined arrangement or orientation of the clamping body 9 , The on the inner ring 11 arranged convex receiving pockets 17 with regard to the mutual arrangement of the kidney-shaped clamping body 9 Usually designed circular section, allow a simple block-wise arrangement of the clamping body 9 , because after each block similarly inclined clamping body 9 a convex receiving bag 17 is released before the next block with oppositely inclined clamp body 9 follows.

After the actuation of the clamp body 9 through the electromagnetic device 15 are all sprags 9 erect and touch without a freewheeling gap 32 the friction contact surface 16 of the outer ring 12 , Depending on the direction of rotation of the inner ring 11 and the outer ring 12 or the torque transmission direction of the two coupling partners are inclined in a direction of rotation, block-wise arranged clamping body 9 in further torque transmission operation in frictional contact with the Reibkontaktfläche 16 of the outer ring 12 and thus enable the transmission of the rotational movement or of the torque. Opposite are the other blocks with sprags 9 that are not involved in torque transmission between the two coupling partners, in no frictional contact with the outer ring 12 However, depending on the Operation of the return device the outer ring 12 touch.

5 shows a perspective assembly drawing of the freewheel device according to the invention 8th out 2 , In this drawing, the arrangement of the spring ring 14 to about half the length of the clamp body 9 and the return of the spring ring 14 opposite the friction side 18 the clamp body 9 easy to recognize. In this representation is still the outer ring 12 from the pulley ring 13 shown separately and subtracted, so that in 5 a clear view of the blocks on the inner ring 11 arranged clamping body 9 is possible. In this illustration is also the division of the electromagnetic device 15 in a support ring 20 and a coil 21 to recognize. Because the support ring 20 not in contact with the crankshaft 3 stands and also on the clamp body 9 acting and from the coil 21 generated magnetic flux for actuating the clamping body 9 requires no contact and also no joint movement, the support ring 20 and thus the entire electromagnetic device 15 opposite the crankshaft 3 and the inner ring 12 be executed fixed. The opposite the crankshaft 3 fixed arrangement allows direct supply of the coil 21 the electromagnetic device 15 with electrical power, without a constructive or inductive transmission of electrical current to a rotating electromagnetic device 15 to need. As coils 21 There, in principle, all known but also novel electrical components are suitable, which provide a magnetic field via the clamping body 9 For example, windings of a conductor made of wire around a solid body or without solid body, but also spirally printed on printed circuit boards with or without an enclosing ferrite core.

In 6 is an axial sectional view through a crankshaft by-drive 2 with a freewheel device according to the invention 8th shown, where 7 a perspective view of this axial sectional drawing shows. The crankshaft by-drive 2 is in this embodiment with a planetary gear 22 equipped, in addition to a sailing operation, with a freewheel device 8th in freewheeling position, and a generator mode, with a freewheel device 8th in a coupling position, also to allow a starter operation. This is the planetary gear 22 so with the secondary disc ring 13 coupled, that induced by the electric machine rotational movement with a reduction of about 1: 5 to the crankshaft 3 is transmitted in order to start the associated internal combustion engine after a sailing operation of the motor vehicle without delay.

That in the crankshaft by-drive 2 integrated planetary gear 22 is with one on the crankshaft 3 Fixed planet carrier 23 provided in common with the inner ring 11 on a flange-like widening at the crankshaft end 24 is trained. On the planet carrier 23 are three planetary gears arranged evenly around the circumference 25 provided, which is rotatable relative to the planet carrier 23 are. The planet wheels 25 engage in an externally toothed sun gear 26 one on the one at the crankshaft end 24 arranged bearings 27 rotatable relative to the crankshaft 3 is stored. The sun wheel 26 is over an inside pin 28 firmly with the pulley wheel 13 connected so that also the pulley wheel 13 rotatable relative to the crankshaft 3 is stored. Furthermore, the planetary gears would come 25 with an internally toothed ring gear 29 that together with the outer ring 12 is trained.

In generator operation of the motor vehicle, the clamping body 9 the freewheel device 8th in the coupling position, thus connecting the inner ring 11 rotatably with the outer ring 12 , Corresponding are also the ring gear 29 and the planet carrier 23 of the planetary gear 22 rotatably positioned to each other, so that also according to the planet carrier 25 and the gear 26 and the pulley ring 13 non-rotatable with the crankshaft 3 are connected. Therefore, in the generator operation, a rotational movement of the crankshaft 3 without translation on the pulley ring 13 and thus on the runner 1 transfer. In sailing operation are the clamp body 9 the freewheel device 8th in its freewheeling position, so that the outer ring 12 and the ring gear 29 independent of the crankshaft 3 can move. It is true that the pulley ring turns in sail operation 13 by driving the by-drive 1 by means of the electric machine, so that also the sun gear 26 rotates. The rotational movement of the sun gear 26 is on the planet carrier 25 and from there to the ring gear 29 transfer. Because the ring gear 29 However, free running, the rotational movement in the planetary gear 22 in sailing mode not on the one with the crankshaft standing 3 firmly connected planet carrier 23 transfer. On the other hand, during starter operation, the ring gear 29 by means of an axial freewheel device (not shown) on the motor housing 30 set, so that when driving the pulley ring 13 through the runner 1 the rotational movement of the planet gears 25 on the ring gear 29 supports and to a rotation of the planet carrier 23 and the associated crankshaft 3 leads. In this case, the rotational movement corresponding to the tooth ratio of the ring gear 29 to the sun wheel 26 stocky to the crankshaft 3 to provide sufficient torque to start the engine.

8th shows an enlarged rotated detail view of the inner ring 11 arranged clamping body 9 the freewheel device 8th and the electromagnetic device 15 , As you can see in this detail view, the coil is 21 and the support ring 20 the electromagnetic device 15 with a small gap, but non-contact, against the inner ring 11 and the sprags 9 arranged so that the inner ring 11 and the clamp body 9 independent of the electromagnetic device 15 can move. In addition to the blockwise arrangement of the clamp body 9 and the remaining between the blocks free of convex receiving pockets 17 of the inner ring 11 Here is also very good, the round spring ring in cross-section 14 and its arrangement in a semicircular groove 31 to recognize. The semicircular groove 31 is about in the middle of the elongated clamp body 9 provided and designed so deep that the spring ring 14 opposite the friction side 18 the clamp body 9 is set back.

A greatly enlarged view of the electromagnetic device 15 shows the detailed view of the section through the freewheel device 8th in 9 , In addition to the distances between the electromagnetic device 15 and the inner ring 11 with sprags 9 as well as the outer ring 12 is clearly in this drawing in the freewheeling position shown here, the freewheeling gap 32 between the clamping bodies 9 and the outer ring 12 in the area of the friction contact surface 16 to recognize. In addition, this detailed view illustrates the magnetic flux of force 33 through the coil 21 upon activation of the electromagnetic device 15 , On the side of the clamp body 9 the magnetic flux of force flows 33 starting from the crankshaft facing end face of the coil 21 through the support ring 20 , through the adjoining inner ring 11 and the clamp body 9 to the outer ring 12 and from there back into the crankshaft 3 facing away from the end of the coil 21 , To the resistance in this magnetic flux 33 reduce the clamping body to reduce 9 against the spring force of the spring ring 14 from its inclined freewheeling position in a direction of magnetic flux oriented coupling position, so that the friction side 18 the clamp body 9 and the friction contact surface 16 of the outer ring 12 touch and the freewheeling gap 32 through the clamp body 9 is bridged. This reduces the resistance to magnetic flux 33 , Since the magnetic field has the aspiration the resistance of the magnetic flux 33 which is lower in a solid, in particular in a magnetizable material, than in an air gap, is the lower resistance of the magnetic flux 33 in the coupling position of the clamping body 9 at the same time the drive for moving the clamp body 9 from the freewheeling position in the coupling position against the spring force of the spring ring 14 ,

In the following, the function and operation of the inventive freewheel device described above 8th explained in more detail.

The freewheel device described here 8th is in a crankshaft secondary drive wheel 2 for driving a secondary drive 1 by means of the crankshaft 3 arranged via an internal combustion engine. By using the freewheel device 8th can the by-drive 1 be used both for a sailing operation of a motor vehicle and for the conventional generator operation. In the freewheeling position of the clamp body 9 the freewheel device 8th can the by-drive 1 operated by the drive by means of an electric machine necessary for the operation of the vehicle ancillaries regardless of the internal combustion engine. In the coupling position of the clamp body 9 is the crankshaft 3 with the crankshaft secondary wheel 2 coupled, so that the rotational movement generated by the internal combustion engine via the crankshaft 3 on the runner 1 is transferred to the secondary drive 1 both to drive the ancillaries, as well as to provide electricity for the vehicle electrical system and for storing the electrical energy via the electric machine.

To the freewheel device 8th to transfer from a freewheeling position to a clutch position and thereby the crankshaft 3 selectively with the crankshaft secondary wheel 2 to couple is through the electromagnetic device 15 creates a magnetic field that spreads over the inner ring 11 and the outer ring 12 as well as the interposed clamping body 9 extends. In a simple embodiment, the electromagnetic device 15 from a support ring 20 and one approximately parallel to the clamping bodies 9 arranged coil 21 so that by means of the coil 21 generated magnetic field very close to the moving clamping bodies 9 is positioned. In addition, the electromagnetic device 15 over the support ring 20 fixed against the rotating inner ring 11 of the first coupling partner and outer ring 12 positioned the second coupling partner, so that a firm connection with, for example, the motor housing 30 and also a direct connection of the coil 21 to an external power grid is possible, for example, the electrical system of a motor vehicle.

Located in the magnetic field of the electromagnetic device 15 resulting magnetic flux 33 also extends through the relative to the magnetic field lines inclined arranged clamping body 9 and the freewheeling gap 32 between the clamping bodies 9 and the outer ring 12 , Since the magnetic field strives for the resistance of the magnetic power flow 33 to reduce that over the freewheeling gap 32 is much larger than via the clamping body preferably made of a magnetizable material 9 , are caused by the effect of magnetic flux 33 the clamp body 9 erected from its inclined freewheeling position in the upright coupling position. As a result, the freewheeling gap 32 bridged between the two coupling partners and correspondingly reduced the resistance in the magnetic field. It must be on the clamp body 9 acting magnetic force flow 33 for erection of the clamping body 9 be larger than that on the clamp body 9 acting spring force of the spring ring 14 ,

After the selective coupling of the two coupling partners by the erection of the clamping body 9 arises between the friction side 18 the erected clamp body 9 and the friction contact surface 16 of the outer ring 12 a frictional contact, so that a torque can be transmitted between the two clutch partners, here the drive torque of the internal combustion engine via the crankshaft 3 and the crankshaft secondary wheel 2 to the runner 1 , In a bidirectional freewheel device 8th In this case, the torque is only on the trained for the transmission of torque in this direction of rotation or arranged clamping body 9 transferred while the other clamp body remain functionless. To a sufficient for torque transmission contact, or sufficient friction between clamping body 9 and outer ring 12 to provide the clamp body 9 in a bidirectional freewheel device 8th Blockwise on the inner ring 11 arranged. The transmission of torque between the two clamp bodies 9 leads over the frictional contact between the friction side 18 the clamp body 9 and the friction contact surface 16 of the outer ring 12 to a self-locking of the clamp body in the clutch position, as long as the torque transmission between the two clutch partners stops. Consequently, immediately after the beginning of the torque transmission, that of the electromagnetic device 15 generated magnetic field are deleted and the electromagnetic device 15 turned off. An activation of the clamping body 9 by means of the electromagnetic device 15 is therefore only directly at the transfer of the clamp body 9 from the freewheeling position into the coupling position necessary, while in the remaining operating time of the generator operation, but also during the sailing operation, a power supply of the electromagnetic device 15 or the coil 21 is not necessary. Accordingly, the freewheel device according to the invention allows 8th despite one for the construction of the magnetic field via the clamping body 9 necessary relatively high energy impulse compared to conventional actively actuated freewheel devices energy savings in a simple design, as an actuation only in the short moments of transfer of the clamp body 9 in the coupling position is necessary and the coupling partners in the coupling position inherently on the clamp body 9 connected to each other.

QUOTES INCLUDE IN THE DESCRIPTION

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Cited patent literature

• DE 3911075 A1 [0004]
• DE 10327213 A1 [0004]

Claims (15)

Freewheel device ( 8th ) for selectively connecting two coupling partners with at least one clamping body ( 9 ) which is arranged between the two coupling partners and can be transferred from a freewheeling position into a coupling position; characterized in that an electromagnetic device ( 15 ) for actuating the at least one clamping body ( 9 ) is provided, which by means of a on the at least one clamping body ( 9 ) acting magnetic flux the at least one clamping body ( 9 ) transferred from the freewheeling position to the coupling position. Freewheel device ( 8th ) according to claim 1, characterized in that the at least one clamping body ( 9 ) is made at least in part of a magnetizable material, preferably of a ferromagnetic material. Freewheel device ( 8th ) according to claim 1 or 2, characterized in that the at least one clamping body ( 9 ) is formed self-holding in the coupling position. Freewheel device ( 8th ) according to one of claims 1 to 3, characterized in that the at least one clamping body ( 9 ) is pivotally mounted on one of the two coupling partners and is in the coupling position in a frictional contact or positive engagement with the other of the two coupling partners. Freewheel device ( 8th ) according to one of claims 1 to 4, characterized in that a restoring device is provided which the at least one clamping body ( 9 ) holds in the freewheeling position and / or transferred from the clutch position to the freewheeling position. Freewheel device ( 8th ) according to one of claims 1 to 5, characterized in that the two coupling partners are designed for torque transmission in two directions of rotation, wherein the two coupling partners by means of the at least one clamping body ( 9 ) in the coupling position are selectively connected in one direction of rotation or the other direction of rotation. Freewheel device ( 8th ) according to one of claims 1 to 6, characterized in that the electromagnetic device ( 15 ) is arranged independently of the two coupling partners, in particular fixedly opposite the two clutch partners movably arranged for transmitting torque. Freewheel device ( 8th ) according to one of claims 1 to 7, characterized in that the two coupling partners are arranged concentrically to each other and a plurality of clamping body ( 9 ) are provided between the two coupling partners, wherein the clamping body ( 9 ) in the freewheeling position on the inner first coupling partner with a freewheeling gap ( 32 ) are arranged to the outer second coupling partner, and wherein the clamping body ( 9 ) are in the coupling position in a frictional contact or positive contact with the outer second coupling partner to connect the two coupling partners together. Freewheel device ( 8th ) according to claim 8, characterized in that the clamping body ( 9 ) kidney-shaped, wherein the kidney-shaped clamping body ( 9 ) are preferably arranged block by block on the inner first coupling partner and each block is associated with one of the two directions of rotation of the concentrically arranged two coupling partners. Freewheel device ( 8th ) according to claim 9, characterized in that the kidney-shaped clamping body ( 9 ) perform a pivoting movement when transferring from the freewheeling position to the coupling position. Freewheel device ( 8th ) according to one of claims 8 to 10, characterized in that the inner first coupling partner with a plurality of convex receiving pockets ( 17 ) is formed, in which the clamping body ( 9 ) are at least partially included. Freewheel device ( 8th ) according to one of claims 8 to 11, characterized in that as restoring means a spring element ( 14 ) is provided, in particular a circumferential elastic ring, which the clamping body ( 9 ) in the freewheeling position on the inner first coupling partner with a freewheeling gap ( 32 ) holds to the outer second coupling partner and / or the clamping body ( 9 ) transferred from the clutch position to the freewheeling position on the inner first clutch partner. Freewheel device ( 8th ) according to claim 12, characterized in that the clamping body ( 9 ) with a groove ( 31 ) are provided in the spring element ( 14 ) is arranged. Gear unit, in particular for coupling a crankshaft ( 3 ) of an internal combustion engine by means of a switchable planetary gear ( 22 ) with one in a secondary drive ( 1 ) arranged electric machine, with a freewheel device ( 8th ) according to one of claims 1 to 13. Method for selectively connecting two coupling partners of a freewheel device ( 8th ) with at least one clamping body ( 9 ) and one electromagnetic device ( 15 ) for actuating the at least one clamping body ( 9 ) comprising the steps of: - generating a magnetic field by the electromagnetic device ( 15 ), wherein the at least one clamping body ( 9 ) is disposed in the magnetic field; Erecting the at least one clamping body ( 9 ) from the freewheeling position to the coupling position for bridging the freewheeling gap ( 32 ) between the two coupling partners; - coupling the two coupling partners by the at least one clamping body ( 9 ); - Transferring a torque between the two clutch partners; Self-locking of the at least one clamping body ( 9 ) in the coupling position by means of the torque transmission between the two clutch partners; - switching off the magnetic field.

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