WO2012048842A1 - Coupling arrangement - Google Patents

Abstract

The invention relates to a coupling arrangement comprising a clutch which is disposed on a rotating shaft (2, 3) in order to couple the rotating shaft as required to a drive element, wherein for coupling the rotating shaft to the drive element (25) a first clutch part (20) can be brought into positive engagement with a second clutch (21) part by offsetting along the axis of the rotating shaft relative to the second clutch part, and a lifting magnet arrangement (27) for actuating the clutch, wherein the lifting magnet arrangement comprises a field coil (29) for producing a magnetic field and an armature (31) which can be attracted by the magnetic field of the field coil along a lifting direction. The armature and the first clutch part to be offset are movable separately from one another and a spring unit (33) is provided which acts between the armature and the first clutch part in the lifting direction and which biases the first clutch part relative to the armature in the lifting direction (H).

Description

 COUPLING ARRANGEMENT

The present invention relates to a coupling arrangement, in particular for a drive train of a motor vehicle, having at least one coupling which is arranged on a rotating shaft to selectively couple the rotating shaft with a drive element, wherein for coupling the rotating shaft with the drive element, a first Kupp - Releasing part by displacement along the axis of the rotating shaft relative to a second coupling part in a form-locking engagement with the second coupling part, and a Hubmagnetanordnung for actuating the clutch, wherein the Hubmagnetanordnung an excitation coil for generating a magnetic field and by the magnetic field of the excitation coil comprises armature which can be attracted along a stroke direction.

The drive element to be coupled to the rotating shaft may be a further shaft or a transmission element. For example, upon actuation of the clutch, a positive connection between the rotating shaft on the one hand and an input shaft, an output shaft, a housing or a crown wheel of a differential gear, or a gear of an angular gear on the other hand can be provided. Such devices can be used for example in the form of so-called disconnect systems for decoupling of parts of a drive train in a motor vehicle with switchable four-wheel drive, so that in two-wheel drive, the connection between the primary axis or the drive unit on the one hand and the secondary axis on the other hand can be at least partially shut down. In general, the torque transmission from the rotating shaft as an input element to the

CONFIRMATION COPY called drive element as the starting element, or in the reverse direction.

In the context of the present invention, the directional indications "axial" and "radial" always refer to the axis of the rotating shaft.

A solenoid for actuating the clutch allows for a hydraulic or pneumatic actuator a particularly simple and inexpensive construction. To amplify the magnetic force, the excitation coil of the lifting magnet can be wound around a yoke or a core of magnetizable material. Between the armature and the exciter coil or a front abutment surface of the yoke there is generally an air gap through which the maximum Verstellhub is given.

In order to fully engage a positive coupling such as a dog clutch, the two rotating at different speeds coupling parts must first be synchronized. This can be done for example by means of a lock synchronization. However, such lock synchronizers are relatively complex and expensive. In addition, the complete engagement of the clutch can be prevented even when synchronization, for example, if there is a "tooth on tooth" position. The actuation force must then be maintained until the two coupling parts have reached a "tooth gap" position due to a residual rotational speed difference.

It is an object of the invention to allow for coupling arrangements of the type mentioned a simpler, more effective and less expensive operation of the clutch. The object is achieved by a coupling arrangement with the features of claim 1. According to the invention, the armature and the first coupling part to be displaced are movable apart from each other and there is provided an effective between the armature and the first coupling part in the stroke direction spring device, which faces the first coupling part biases the anchor in the stroke direction. The armature and the first coupling part to be displaced are therefore not rigidly coupled with each other, but flexible via a spring. Now, if a movement of the first coupling part along the stroke direction has been stopped due to a "tooth on tooth" position of the coupling parts, further movement of the armature along the stroke direction is permitted under tensioning of the spring. In the tensioned spring, the force is stored for final engagement or switching through the clutch until the claws of the two coupling parts have taken the correct position to each other. The armature of the Hubmagnetanordnung must not be moved for switching through. The invention thus makes it possible to connect a dog clutch with a simple and inexpensive Hubmagnetanordnung at any time.

Further developments of the invention are specified in the dependent claims, the description and the accompanying drawings.

The first coupling part is preferably coupled to the armature via a driver device in such a way that, when the armature moves counter to the stroke direction, the armature entrains the first coupling part. By the driver is ensured that despite the flexible coupling of the first coupling part with the armature via the spring means a effective return movement of the first coupling part when opening the clutch takes place. The driver can be in particular a Hintergreifung. The spring device is preferably effective on pressure. For example, can be arranged between a front end face of the armature seen in the stroke direction and a rear end face of the first coupling part, a compression spring. This is compressed in an axial movement of the armature in the stroke direction, provided that the first coupling part is prevented from axial movement.

According to one embodiment of the invention, the spring device is effective between the first coupling part and a component rotationally coupled to the armature or between the armature and a component rotationally coupled to the first coupling part. This makes it possible in an advantageous manner to perform the lifting magnet assembly fixed to the housing. In particular, the spring device can be connected to the first coupling part and be supported on the anchor via at least one thrust bearing. The armature is rotationally coupled by the first coupling part through the axial bearing and can be fixedly mounted in the housing.

Furthermore, a return spring acting in particular between the excitation coil and the armature can be provided, which biases the two coupling parts, preferably in the opening direction, relative to one another. Such a return spring makes it possible, for example, to open the clutch only to interrupt the power supply of Hubmagnetanordnung.

According to one embodiment of the invention, the first coupling part as a coaxial to the rotating shaft sliding sleeve, in particular with frontal claws, executed. This allows a simple, cylindrical construction of the coupling arrangement. In particular, no levers are necessary, which must be stored in the housing. According to a further embodiment of the invention, the first coupling part is coupled to a synchronization element, which is axially movable relative to the first coupling part and can be latched in a basic position with the first coupling part. In the latched position, the actuating force is thus transmitted from the first coupling part to the synchronization element, which thus comes into operation and sets the synchronization of the two coupling parts in motion. After synchronization of the coupling parts, the latching between the synchronization element and the first coupling part can be released, so that the synchronization element is decoupled axially from the first coupling part and thus losses are minimized.

In particular, the synchronization element may have a friction cone, which cooperates in the basic position with a friction cone of the second coupling part when the armature is tightened. The course of the synchronization force can be controlled by driving the Hubmagnetanordnung, i. be adjusted by the height and duration of the magnetic force, according to the application. The latching mechanism ensures that, when a maximum force acting in the stroke direction is exceeded, the axial coupling between the synchronization element and the first coupling part is released.

For latching the first coupling part and the synchronizing element, a ball mounted in the synchronization element and spring-biased in the radial direction can be provided, which in one Recess of the first coupling part snaps or vice versa.

This allows a particularly simple construction.

According to a further embodiment of the invention, the first coupling part can form an outer sleeve and the synchronization element can form an inner sleeve of a cylinder-like sliding component. It can thus be provided, so to speak, a two-part sliding sleeve in the radial direction, which equally provides the synchronization effect and causes the positive engagement.

Preferably, the Hubmagnetanordnung in a closed position of the coupling to a vanishing air gap. At a zero air gap, there is a relatively low magnetic resistance, so that the electric power to hold this position is minimal. The holding of the clutch in the closed position can thus be particularly energy-efficient.

The invention will now be described by way of example with reference to the drawings.

Fig. 1 is a sectional view of a coupling arrangement according to an embodiment of the invention, wherein a coupling of the coupling arrangement is shown in an open position.

Fig. 2 shows the coupling arrangement according to Fig. 1 at the beginning of a synchronization process. FIG. 3 shows the coupling arrangement according to FIG. 1 at a first time during a synchronization process. FIG. 4 shows the coupling arrangement according to FIG. 1 at a second, later point in time during a synchronization process.

FIG. 5 shows the coupling arrangement according to FIG. 1 after completion of a synchronization process.

FIG. 6 shows the coupling arrangement according to FIG. 1 with a clutch in the closed position. FIG. 7 is a force-displacement diagram illustrating the force curves on the coupling arrangement of FIG. 1 during various operating conditions. FIG.

Fig. 8 is a sectional view of a coupling assembly according to an alternative embodiment of the invention, showing a coupling of the coupling assembly in an open position.

FIG. 9 shows the coupling arrangement according to FIG. 8 at a first time during an engagement process.

FIG. 10 shows the coupling arrangement according to FIG. 8 at a second, later point in time during an engagement process. FIG. 11 shows the coupling arrangement according to FIG. 8 with a coupling in the closed position.

1 to 6 a coupling arrangement according to a first embodiment of the invention is shown, which can be used at different positions within a drive train of a motor vehicle to selectively couple two components of the drive train with each other. In particular, the coupling arrangement can form a longitudinal or a transverse disconnect system in a motor vehicle with manually or automatically connectable four-wheel drive.

In principle, it is also conceivable to decouple an internal combustion engine from the primary drive train by means of the coupling arrangement in order to reduce losses which result from further rotation of drive train components such as manual or automatic transmissions when the vehicle is rolling or when driven by an electric motor at the secondary axis. Likewise, in a hybrid vehicle powered by an electric motor on the secondary axle, the coupling assembly may be used to decouple the electric motor from the driveline when it is not needed or when excessive speed increase is to be prevented.

The coupling arrangement comprises a dog clutch 11, which is arranged on an input half-shaft 23 rotating about an axis of rotation R. The dog clutch 11 comprises a first coupling part 20 and a second coupling part 21, which each have end-side jaws 22 and which can be brought together for closing the dog clutch 11 in a form-locking engagement. The first coupling part 20 is coupled to the input half-wave 23, which is for example coupled to a front axle differential of the motor vehicle. The second coupling ment part 21 is coupled to an output half-wave 25, which in turn is coupled, for example with a rear differential of the motor vehicle. When the two coupling parts 20, 21 are in positive engagement, the dog clutch 11 is engaged or closed and there is a torque transmission from the input half-shaft 23 to the output half-shaft 25, so for example from the front to the rear axle of the drive train instead , On the other hand, when the two clutch parts 20, 21 are not engaged with each other, the dog clutch 11 is opened and the input half-shaft 23 is disconnected from the output half-shaft 25. The opening and closing of the dog clutch 11 takes place by the first coupling part 20 being displaced along the axis of rotation R relative to the second coupling part 21.

For this purpose, a Hubmagnetanordnung 27 is provided, which comprises an excitation coil 29 for generating a magnetic field and an attractable by the magnetic field of the excitation coil 29 along a stroke direction H anchor 31. The excitation coil 29 can be controlled by means of a control device, not shown, so as to attract the armature 31 with a predetermined actuating force of predetermined duration.

The armature 31 and the first coupling part 20 are movable separately from one another in the direction of the rotation axis R, but are coupled to one another via a storage spring 33 on the one hand and a rear engagement 35 on the other hand. The pressure-effective accumulator spring 33 is supported on the one hand on a viewed in the stroke direction H rear end 38 of the first coupling part 20 and on the other hand on a transmission ring 36, which in turn is supported via a thrust bearing 37 on the armature 31 fixed to the housing. The accumulator spring 33 thus biases the first coupling part 20 with respect to the transmission ring 36 and consequently with respect to the armature 31 in the stroke direction H. The thrust bearing 37 causes a rotary Decoupling between the transmission ring 36 and the armature 31. A acting between the transmission ring 36 and the input half-wave 23 return spring 39 biases the jaw clutch 11 in the opening direction. The return spring 39 could alternatively be arranged between the exciter coil 29 and the armature 31. The formed between the first coupling part 20 and the transmission ring 36

Rear engagement 35, in conjunction with the restoring spring 39, ensures that, when the armature 31 moves counter to the stroke direction H, the armature 31 carries along the first coupling part 20 via the transmission ring 36.

As is apparent from FIGS. 1-6, the sleeve-shaped first coupling part 20 encloses a radially inwardly located, likewise sleeve-shaped synchronization ring 40, whereby a two-part sliding sleeve is formed overall. The synchronizing ring 40 is axially movable relative to the first coupling part 20, but can be latched via a latching device 43 in a basic position with this. In the illustrated embodiment, the latching device 43 is formed by a ball 45 mounted in the synchronization ring 40 and prestressed in the radial direction by a detent spring 47, which in the basic position snaps into a groove 49 of the first coupling part 20. Likewise, the ball could also be mounted in the first coupling part 20 and snap into a groove of the synchronization ring 40. On the front face 51 of the synchronizer ring 40 seen in the stroke direction H, a projecting frictional cone 53 is formed, which is able to cooperate with a frictional cone 55 of the second coupling part 21. Since the first friction cone 53 and the second friction cone 55 are arranged projecting with respect to the claws 22, when the synchronization ring 40 is in the home position, the first friction cone 53 and the second friction cone 55 arrive during tightening of the armature 31 before the claws 22 of the coupling parts 20, 21 come into engagement.

In the open position of the dog clutch 11 shown in FIG. 1, neither the claws 22 of the first coupling part 20 and the second coupling part 21 are in frictional engagement with the first friction cone 53 and the second friction cone 55 in frictional engagement. By the return spring 39, the dog clutch 11 is held in this open position, wherein the power supply to the field coil 29 is interrupted, so that no electrical energy is consumed.

To close the dog clutch 11, the exciting coil 29 is supplied with an electric current and the armature 31 is attracted by the corresponding magnetic force. The armature 31, in turn, pushes the transmission ring 36 and, via the storage spring 33, the first coupling part 20 in the stroke direction H. Initially, only the clearance of the dog clutch 11 is traversed until the first friction cone 53 and the second friction cone 55 come into contact (FIG ). During the further tightening of the armature 31 shown in FIGS. 3 and 4, a rotational speed equalization of the two coupling parts 20, 21 takes place, wherein the magnetic force can be increased stepwise, as illustrated by the field lines in FIGS. 2 to 6. Specifically, the course of the synchronization can be adjusted as desired both via the control of the exciter coil 29 and on the characteristic of the storage spring 33. The storage spring 33 is tensioned during the synchronization process.

If, as shown in FIG. 5, the synchronizing process is completed, a further increase in the magnetic force causes the latching device 43 to release. The spring force of the storage spring 33 then no longer overflows the ball 45 is transmitted to the synchronizing ring 40, so that the synchronizing device formed by the first friction cone 53 and the second friction cone 55 is substantially free of forces. The claws 22 of the first coupling part 20 and the second coupling part 21 will in many cases first come into contact with each other in a "tooth-to-tooth" position. The movement of the first coupling part 20 in the stroke direction H is thus stopped before a complete closing of the dog clutch 11 has taken place. Due to the flexible coupling of the first coupling part 20 with the armature 31 via the storage spring 33, however, the armature 31 can move under further tensioning of the storage spring 33 into its end position shown in FIG. 5 with a vanishing air gap. The exciter coil 29 must be supplied in this end position only with a minimum holding current, since due to the vanishing air gap, the magnetic resistance of the Hubmagnetan- order 27 is low.

The accumulator spring 33 remains taut and has sufficient power reserves to cause the dog clutch 11 to shift into the final closed position as soon as the claws 22 have reached a suitable "tooth gap" position. When switched through, the accumulator spring 33 relaxes by the clearance of the dog clutch 11. However, the armature 31 remains rigidly in its end position during the final through-connection. The accumulator spring 33 is designed so that it relaxes during the passage through the dog clutch 11 to a predetermined minimum force, which prevents accidental opening of the dog clutch 11 straight. To reopen the dog clutch 11, the current is turned off to the exciter coil 29, whereupon the return spring 39, the first coupling member 20 pushes back into the starting position. The synchronization ring 40 locks again in its basic position with the first coupling part 20th In the force-displacement diagram according to FIG. 7, forces F occurring during the closing and during the opening of the dog clutch 11 are shown in a simplified manner as a function of the travel s of the armature 31. The tightening force of the lifting magnet arrangement 27 is shown as a dashed line 57, the tightening force reduced by the spring force of the return spring 39 as a solid line 59. The line 61 characterizes the spring force of the storage spring 33. In the region 63, the storage spring 33 is tensioned or relaxed. At 65 is the point at which it comes to a "tooth on tooth" position.

8 to 11 show a coupling arrangement according to an alternative embodiment of the invention, wherein identical or equivalent components are denoted by the same reference numerals as in the embodiment according to FIGS. 1 to 6. The first coupling part 20 'is here by a one-piece sliding sleeve formed, ie no synchronizing ring is provided. This variant does not offer a synchronization function, but is less expensive than the embodiment according to FIGS. 1 to 6. In particular, fewer components and components that are easier to manufacture are required. By replacing the split sliding sleeve - with synchronizing function - with a one-piece sliding sleeve - without synchronization function - a modular system can be realized in a simple way. That Optionally, a synchronized dog clutch 11 or a less expensive, non-synchronized dog clutch 11 'may be provided using many of the same or similar components.

An important advantage of the invention is that the exciter coil 29 and the armature 31 are fixed to the housing and do not have to transmit any mechanical power. The magnetically conductive parts are therefore of the mechanically clean parts separated clean, which is advantageous in that a high magnetic conductivity is basically associated with a low mechanical strength and vice versa. In a construction according to the invention, components which have to transmit a torque do not conduct or magnetically insulate a magnetic field and can therefore be produced from high-strength standard materials. Conversely, all magnetic field leading parts do not require high mechanical strength and can thus be advantageously made of soft iron.

Overall, the invention enables a simple and inexpensive to implement claw clutch 11, 1 Γ, which manages without a complicated lock synchronization.

LIST OF REFERENCE NUMBERS

11, 11 'dog clutch

 20, 20 'first coupling part

21 second coupling part

 22 claw

 23 input half-wave

25 output half-wave

27 Hubmagnetanordnung

29 exciter coil

 31 anchors

 33 memory spring

 35 Hintergreifung

 36 transmission ring

37 thrust bearings

 38 rear face

 39 return spring

 40 sync ring

43 locking device

45 ball

 47 detent spring

 49 groove

 51 front end

 53 first friction cone

55 second friction cone

 57 tightening force

 59 reduced tightening force

 61 spring force

 63 tensioning / relaxing area

65 point of a "tooth on tooth" position R rotation axis

H stroke direction F force

s way

Claims

claims Coupling arrangement, in particular for a drive train of a motor vehicle, with  at least one coupling (11, 1Γ) disposed on a rotating shaft (23) for selectively coupling the rotating shaft (23) to a drive element (25), the coupling of the rotating shaft (23) with the drive element (25) a first coupling part (20, 20 ') by displacement along the axis (R) of the rotating shaft (23) relative to a second coupling part (21) in a form-locking engagement with the second coupling part (21) can be brought, and  a Hubmagnetanordnung (27) for actuating the clutch (11, 1 Γ), wherein the Hubmagnetanordnung (27) comprises an excitation coil (29) for generating a magnetic field and by the magnetic field of the excitation coil (29) along a stroke direction (H) attractable anchor ( 31), By doing so, that is the armature (31) and the first coupling part (20, 20 ') to be displaced are movable apart from one another and a spring device (33) is provided between the armature (31) and the first coupling part (20, 20') in the stroke direction (H) is, which biases the first coupling part (20, 20 ') relative to the armature (31) in the stroke direction (H). Coupling arrangement according to claim 1, characterized in that  the first coupling part (20, 20 ') is coupled to the armature (31) via a driver device (35) such that upon movement of the armature (31) against the stroke direction (H) of the armature (31), the first coupling part (20 , 20 '). 3. Coupling arrangement according to claim 1 or 2,  characterized in that  the spring device (33) is effective for pressure. 4. Coupling arrangement according to at least one of the preceding claims,  characterized in that  the spring device (33) is effective between the first coupling part (20, 20 ') and a component (36) rotationally coupled to the armature (31) or between the armature (31) and a component rotationally coupled by the first coupling part (20, 20') is. 5. Coupling arrangement according to claim 4,  characterized in that  the spring device (33) is connected to the first coupling part (20, 20 ') and is supported on the armature (31) via at least one axial bearing (37). 6. Coupling arrangement according to at least one of the preceding claims,  characterized in that a, in particular between the excitation coil (29) and the armature (31) effective, return spring (39) is provided which the two Clutch parts (20, 20 ', 21), preferably in the opening direction, biased relative to each other. Coupling arrangement according to at least one of the preceding claims, characterized in that the first coupling part (20, 20 ') is designed as a sliding sleeve coaxial with the rotating shaft (23), in particular with end-side claws (22). Coupling arrangement according to at least one of the preceding claims, characterized in that the first coupling part (20) is coupled to a synchronization element (40) which is axially movable relative to the first coupling part (20) and can be latched in a basic position with the first coupling part (20). Coupling arrangement according to claim 8, characterized in that the synchronization element (40) has a friction cone (53) which in the basic position cooperates with a friction cone (55) of the second coupling part (21) when the armature (31) is tightened. Coupling arrangement according to claim 8 or 9, characterized in that for latching the first coupling part (20) and the synchronization element (40) a ball (45) mounted in the synchronization element (40) and spring-biased in the radial direction is provided, which in a recess (49) of the first coupling part (20) snaps or vice versa. Coupling arrangement according to one of claims 8 to 10, characterized in that the first coupling part (20) forms an outer sleeve and the synchronizing element (40) forms an inner sleeve of a cylinder-like sliding component. Coupling arrangement according to at least one of the preceding claims, characterized in that the Hubmagnetanordnung (27) in a closed position of the clutch (11, 1 Γ) has a vanishing air gap.