Torque transfer device

A torque transfer device, in particular in the power train of a motor vehicle, having at least one wet-running clutch device, in particular a multi-plate clutch device, which is actuatable by an actuating lever device, in particular an actuating lever spring device, through a pressure member. The pressure member has a blocking cross section which is opened toward a pressure chamber.

CROSS REFERENCE TO RELATED APPLICATIONS

This patent claims priority of German Patent Application No. 10 2006 049 729.5, filed Oct. 21, 2006, which application is incorporated herein by reference.

BACKGROUND OF THE INVENTION

The invention relates to a torque transfer device, in particular in the power train of a motor vehicle, having at least one wet-running clutch device, in particular a multi-plate clutch device, which is actuatable by means of an actuating lever device, in particular an actuating lever spring device, through a pressure member. A torque transfer device of this type is known for example from German published unexamined application DE 10 2005 027 610 A1.

SUMMARY OF THE INVENTION

The present invention broadly comprises a torque transfer device, in particular in the power train of a motor vehicle, having at least one wet-running clutch device, in particular a multi-plate clutch device, which is actuatable by means of an actuating lever device, in particular an actuating lever spring device, through a pressure member, where the pressure member has a blocking cross section which is opened toward a pressure chamber. According to an essential aspect of the invention, in addition to its pressure force transmitting function the pressure member fulfills at least one other function, such as transferring torque or reducing the leakage from the pressure chamber. The pressure chamber is supplied with a cooling medium that serves to cool the clutch device, for example with the help of a cooling oil pump. The blocking cross section bounds an annular space in which a ring of cooling medium builds up under the effect of centrifugal force during operation of the rotating clutch device. Leakage from the pressure chamber caused by centrifugal force is prevented or reduced by the pressure of the ring of cooling medium.

A preferred exemplary embodiment of the torque transfer device is characterized by the fact that the blocking cross section is essentially C-shaped. The blocking cross section is preferably designed and situated so that a leakage gap issues between the free ends of two legs of the C-shaped blocking cross section.

Another preferred exemplary embodiment of the torque transfer device is characterized by the fact that the blocking cross section bounds an annular space which is connected to the pressure chamber through a leakage gap. A ring of cooling medium collects in the annular space under the effect of centrifugal force during operation of the rotating clutch device.

Another preferred exemplary embodiment of the torque transfer device is characterized by the fact that the pressure member is ring-shaped. The ring-type pressure member is preferably situated between the actuating lever device and a clutch disc, in particular a clutch plate; in particular, it is clampable or is clamped.

Another preferred exemplary embodiment of the torque transfer device is characterized by the fact that the pressure member has at least one torque delivery element, which is connected in a rotationally fixed connection, at a torque transfer interface between the pressure member and a pump drive element that drives a pump, to the pump drive element. Preferably, the torque transfer interface is realized with such a large diameter that the associated contact force, i.e., the unit surface pressure, is sufficiently reduced so that a single torque delivery element is adequate to transfer the torque that occurs in operation.

Another preferred exemplary embodiment of the torque transfer device is characterized by the fact that the pressure member has radially on its inside at least one in particular circular-arc-shaped recess. The recess creates a possibility of meshing for a complementary designed projection which is provided on the pump drive element.

Another preferred exemplary embodiment of the torque transfer device is characterized by the fact that a projection is provided radially outside on the pump element, which meshes with the recess on the pressure member. That creates a rotationally fixed connection between the pump drive element and the pressure member.

Another preferred exemplary embodiment of the torque transfer device is characterized by the fact that the pump drive element is rotatably supported on a bearing element of the clutch device, in particular a plate carrier, by a bearing device with sealing function. The support of the pump drive element on the bearing element is preferably designed so that no cooling oil can escape in the radial direction.

Another preferred exemplary embodiment of the torque transfer device is characterized by the fact that the pressure member has at least one torque delivery element, which is connected in a rotationally fixed connection, at a torque transfer interface between the pressure member and the clutch device, in particular a plate carrier of the clutch device, to the clutch device, in particular to the plate carrier. That makes it possible to transfer torque in a simple manner to drive a cooling oil pump.

Another preferred exemplary embodiment of the torque transfer device is characterized by the fact that the pressure member has radially on its outside at least one driver lug. The driver lug, which is also referred to as a driver cog, creates a positive-locking connection between the pressure member and the clutch device.

Another preferred exemplary embodiment of the torque transfer device is characterized by the fact that a recess is provided on the clutch device, with which the driver lug of the pressure member meshes. Preferably, a plurality of driver lugs is distributed on the circumference of the pressure member, in particular uniformly.

Another preferred exemplary embodiment of the torque transfer device is characterized by the fact that the pressure member is situated between the actuating lever device and a clutch disk, in particular a clutch plate. A plurality of clutch disks, which are also referred to as clutch plates, are pressed together by the pressure member in order to produce a frictional connection.

Another preferred exemplary embodiment of the torque transfer device is characterized by the fact that the pressure member has a pressure lug which is in contact with the clutch disk. The pressure lug preferably extends in the axial direction.

Another preferred exemplary embodiment of the torque transfer device is characterized by the fact that the pressure member, viewed in cross section, has a protuberance with which the actuating lever device is in contact. The magnitude of the diameter on which the protuberance is situated influences the transmission ratio of the actuating lever device.

The invention also relates to a transmission, in particular a double-clutch transmission, having at least one transmission input shaft, in particular having two transmission input shafts, and having a torque transfer device described earlier for transferring torque between a combustion engine and the transmission.

DETAILED DESCRIPTION OF THE INVENTION

Part of power train1of a motor vehicle is depicted inFIG. 1. Situated between drive unit3, in particular a combustion engine, from which crankshaft4extends, and transmission5, is wet operating double clutch6of multiple-disk design. Connected between drive unit3and double clutch6is rotary vibration damping device8. Rotary vibration damping device8is a damped flywheel.

Crankshaft4of combustion engine3is rigidly connected through a screw connection9to input part10of rotary vibration damping device8. Input part10of rotary vibration damping device8essentially has the form of a circular ring disk extending in the radial direction, to which starter gear rim11is welded radially on the outside. In addition, an inertial mass12is welded onto the input part10of rotary vibration damping device8. Inertial mass12and input part10of rotary vibration damping device8form vibration damper cage14, which at least partially incorporates a plurality of energy storage devices, in particular spring devices16.

Output part18of rotary vibration damping device8engages spring devices16. Output part18is connected through connecting part22to input part24of double clutch6in a rotationally fixed connection. Clutch input part24is joined in one piece to outer plate carrier26of a first multi-plate clutch assembly. Positioned radially inside outer plate carrier26is inner plate carrier28of first multi-plate clutch assembly27. Inner plate carrier28is attached to hub piece30, which is connected through toothing to first transmission input shaft31in a rotationally fixed connection. First transmission input shaft31is designed as a solid shaft.

Clutch input part24, or outer plate carrier26of first multi-plate clutch assembly27, which is connected to the latter in a single piece, is connected through connecting part34to an outer plate carrier36of a second multi-plate clutch assembly38in a rotationally fixed connection. In the example shown, connecting part34is connected to outer plate carrier36in a single piece. Positioned radially inside outer plate carrier36is an inner plate carrier40of second multi-plate clutch assembly38, which is connected to hub part41in a single piece. Hub part41is connected through toothing in a rotationally fixed connection to second transmission input shaft42, which is constructed as a hollow shaft. First transmission input shaft31is situated in second transmission input shaft42so that it can rotate.

The two multi-plate clutch assemblies27and38are operated by means of actuating levers44,45, whose radially inner ends are supported on actuating bearings. The actuating bearings are actuated in the axial direction with the help of actuating pistons. Actuating levers44,45are preferably connected to associated diaphragm spring devices in a single piece.

Each friction clutch27,38has input-side and output-side friction units48,49, which may be acted on by means of axial pressing together parallel to axis of rotation50of at least one of transmission input shafts31,42to form a frictional engagement. Friction units48,49of two friction clutches27,38are situated radially one above the other, and are formed of a plurality of frictional companion bodies alternating layer by layer in the axial direction on the input side and output side.

Pressure member59,60is situated in each case between actuating levers44,45and associated friction units48,49. The clamping force to actuate double clutch6is transmitted from actuating levers44,45to associated friction units48,49through pressure members59,60. Pressure member60is connected in a rotationally fixed connection to collar64of drive sleeve65radially on the inside of torque delivery interface61. Radially on the outside of another torque delivery interface62, pressure member60is connected in a rotationally fixed connection to the outer plate carrier36of the second multi-plate clutch assembly.

Drive sleeve65is connected in a rotationally fixed connection to a pump drive element of a pump (not shown) which serves to provide a flow of cooling agent to cool at least one friction clutch27,38. The pump is, for example, an internal gear pump, in particular a gerotor pump, which is driven by means of crankshaft4. Arrows67,68,69indicate that the flow of cooling agent, in particular the flow of cooling oil, provided by the pump, enters into pressure chamber70through an annular space that is formed between transmission input shaft42and drive sleeve65. Pressure chamber70is bounded laterally in the axial direction by radial segment71of inner plate carrier40and by guide ring73. Through a leakage gap between guide ring73and inner plate carrier40or friction unit49, cooling agent from pressure chamber70enters into annular space72, which is bounded by ring-type basic body74of pressure member60.

FIGS. 2 through 4depict pressure member60with ring-type basic body74in three different views. Radially on the outside of ring-type basic body74, which has essentially the form of a circular ring disk, four driver cogs76through79are distributed uniformly around the outer circumference. The driver cogs76through79, which are also referred to as driver lugs, extend radially outward from the outer circumference of the ring-type basic body74. The width of driver cogs76through79decreases toward the outside. Radially on the inside, ring-type basic body74has two diametrically situated recesses82, which have essentially the form of circular arcs.

InFIG. 4it can be seen that ring-type basic body74, viewed in cross section, has a circumferential pressure nose radially on the outside. A leg85of an essentially C-shaped blocking cross section proceeds from the pressure nose84. Leg85is connected in a single piece to a base86, from which another leg87proceeds. In the transition area between the leg85and the base86, ring-type basic body74has a circumferential protuberance89.

According to an essential aspect of the invention, a pressure member of a small size is created, into which various functions are integrated to save additional parts. Pressure member60is preferably made in a single piece as a sheet metal part with great stiffness. Pressure member60according to the invention makes it possible in particular to save a separate pump drive. That enables the costs of the wet-running double clutch to be further reduced. In addition, the cooling oil circuit is improved and the drag torque is reduced by pressure member60according to the invention. That makes it possible to save fuel.

In the wet-running double clutch transmission depicted inFIG. 1, the clutch disks or plates of friction unit49of the second multi-plate clutch assembly38are pressed against the transmission5by pressure member60to transfer the existing torque. In addition, pressure member60according to the invention fulfills two other functions. On the one hand, the inward-drawn pot of the ring-type basic body74, that is, the blocking cross section formed by the base86with the legs85,87, allows an oil ring to be built up in the annular space72, whose pressure prevents greater leakage in the centrifugal oil gap. That supports the cooling function of the clutch plates.

In addition, drive sleeve65is driven rotationally by way of the recesses81,82, which are engaged by corresponding radial projections of the collar64. Additionally, driver cogs76through79engage corresponding cutouts in outer plate carrier36. Thus a rotationally fixed connection is created between outer plate carrier36and drive sleeve65through pressure member60. That enables the engine speed of crankshaft4to be passed along to the cooling oil pump of the double clutch transmission, in order to maintain a constant cooling oil volume flow.

Pressure member60is situated between actuating lever spring45and friction unit49, which are surrounded by the plate pack, and serves first and foremost to build up the clamping pressure in the second multi-plate clutch assembly38. Actuating lever spring45rests against the protuberance89and presses the plate pack of friction unit49together with pressure nose84. The transmission ratio of the actuating lever45for the clutch assembly38is determined with the diameter for clamping the actuating lever spring45in the outer plate carrier36, the diameter of the actuating lever spring45on the associated actuating system, and the diameter of the protuberance of pressure member60.

The support of the pump drive sleeve65on inner plate carrier40, to which guide ring73belongs, is designed so that the cooling oil cannot escape radially. By choosing a suitable bearing, for example a slide bearing, a sealing function can be fulfilled. The bearing is designed so that cooling oil is not influenced in its direction of flow by the bearing, and flows directly into the pressure chamber70.

The cooling oil from the pressure chamber70that does not directly reach the grooves of the friction plates of friction unit49escapes through the leakage gap from the pressure chamber into the annular space72, which is bounded by the base86and the legs85,87of the ring-type basic body74of pressure member60. The rotary motion of the individual components causes the cooling agent to accumulate radially at the outside on the leg85, and builds up a ring of centrifugal oil, whose pressure counteracts further leakage. The differential speed that develops between the parts bounding the pressure chamber70and the pressure member60when clutch assembly60is not actuated supports the buildup effect in the annular space72.

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