DRY DOUBLE CLUTCH WITH INDIVIDUALLY ACTUATORY PARTIAL CLUTCHES

Description

[0001] The present invention relates to a dual clutch for a reversing transmission, for use in a motor vehicle. The motor vehicle is preferably an agricultural machine, in particular a tractor.

[0002] Reversing gearboxes are most commonly used for tractors and implements where frequent switching between forward and reverse travel occurs. These gearboxes are transmissions that allow for at least one reversal of rotation. Such gearboxes are required when a drive system needs to provide two equivalent directions of rotation, but the reversal cannot be achieved by the drive motor itself.

[0003] A dual-clutch transmission with an attached reversing gearbox enables a mostly fully automatic gear change into forward or reverse without interrupting traction, the so-called power shift, and without using a clutch pedal. Torque is transmitted via one of two partial clutches, which connect two partial gearboxes to a single drive. Similar to an automatic transmission with a hydraulic torque converter, this principle also allows gear changes without interrupting traction by simultaneously engaging one partial clutch while the other disengages.

[0004] A dual-clutch transmission typically uses two wet multi-plate clutches or single-plate dry clutches. Single-plate dry clutches are usually standard equipment in compact passenger cars with engines up to approximately 250 Nm of torque, as dissipating the greater heat loss at higher power outputs is difficult.

[0005] Wet dual-clutch transmissions allow for higher torque and vehicle weights within the same size. The heat generated during shifting and starting is dissipated via a cooling oil flow. The transmission itself typically serves as the oil sump. The oil thus serves both to cool the clutch and to lubricate the gear set. A wet dual-clutch transmission always exhibits a certain amount of drag torque when disengaged, resulting in higher idling losses and consequently reduced efficiency. Additionally, the operation of the oil pump further reduces overall efficiency. Furthermore, a wet dual-clutch transmission requires additional components for operation and control.

[0006] Wet double clutches for reversing gearboxes are known from the prior art, which are intended especially for agricultural machinery such as a tractor and are mechanically operated.

[0007] However, such dual clutches often require pull and push actuation in opposite directions to open or close the respective clutch components. Furthermore, wet dual clutches must be equipped with a cooling circuit for the lubricating oil. The corresponding slave / master cylinder assemblies, consisting of actuating levers and bearings, along with the cooling circuit, sometimes require a considerable number of components. Moreover, such an assembly requires significant installation space and a high degree of additional effort for mounting the device. Maintenance is also generally high, especially when used in agricultural machinery.

[0008] From DE 10 2019 116 593 A1, a dual clutch is known in which the directly actuated, normally disengaged partial clutches are engaged by a concentric actuation system. From DE 10 2014 212 416 A1, a lever-actuated multi-plate dual clutch is known in which both levers are actuated by two different groups of actuating pins. From US 2008 / 078642 A1, DE 36 28 693 A1, and DE 695 19 544 T2, tractor dual clutches with a normally engaged drive clutch and a normally disengaged power take-off clutch are known.

[0009] The present invention is based on the objective of overcoming, at least partially, the problems known from the prior art. This objective is achieved by the features of independent claim 1. Further advantageous embodiments of the invention are specified in the dependent claims. The features listed individually in the dependent claims can be combined with one another in a technologically meaningful manner and can define further embodiments of the invention. In addition, the features specified in the claims are further specified and explained in the description, which also presents further preferred embodiments of the invention.

[0010] The dual clutch according to the invention with one axis of rotation comprises a first partial clutch and a second partial clutch, wherein the first partial clutch comprises, in the direction of the axis of rotation, a first pressure plate, a flywheel and an intermediate first clutch disc, wherein the first pressure plate and the first clutch disc are slidably mounted along the axis of rotation, wherein the second partial clutch comprises, in the direction of the axis of rotation, a second pressure plate, a housing projection fixedly connected to a housing, and an intermediate second clutch disc, wherein the second pressure plate and the second clutch disc are slidably mounted along the axis of rotation, further comprising an actuating system with a first actuating lever for the compressive actuating of the first partial clutch and a second actuating lever for the compressive actuating of the second partial clutch.wherein the first and second partial clutches are disengaged in the unactuated state, and wherein at least two return springs are supported with one end on the housing projection and with their other end on the first actuating lever or on the second actuating lever and oppose the direction of actuation of the first and second actuating levers to engage the first and second partial clutches.

[0011] It should be noted as a precaution that the numerical terms used here ("first", "second", etc.) primarily serve (only) to distinguish between several similar objects, quantities, or processes, and thus do not necessarily dictate any dependency and / or sequence between these objects, quantities, or processes. Should a dependency and / or sequence be required, this is explicitly stated here, or it will be obvious to a person skilled in the art upon studying the specific configuration described.

[0012] Preferably, the dual clutch is designed as a dry dual clutch. A wet dual clutch always has a certain amount of drag torque when disengaged, resulting in higher idling losses. These idling losses do not occur with a dry dual clutch. Thus, the dry dual clutch has a higher efficiency compared to a wet design. Furthermore, the dry dual clutch is less complex than a wet dual clutch and requires fewer components, as an oil cooling circuit is not necessary. Consequently, the dry dual clutch also requires less installation space. Due to the reduced complexity, assembly and maintenance efforts are also reduced.Since the dual clutch according to the invention is preferably used in agricultural machinery such as a tractor, the reduction in components of the dual clutch also leads to easier repair, which can be carried out on site, i.e. not in a workshop.

[0013] The double coupling is formed from two partial couplings, wherein the first partial coupling is formed at least from the elements marked "first / s / n...", and wherein the second partial coupling is formed at least from the elements marked "second / s / n...".

[0014] The term "disengaged in the unactuated state" means that the respective sub-clutch is disengaged when the associated actuating lever is not being actuated, i.e., when no actuating force is being exerted. This means that there is no frictional engagement between the respective friction partners of the sub-clutch. A "push actuation" means that, when actuated, the associated actuating lever pushes one of the elements of the respective sub-clutch towards the other, thus exerting a force that causes the respective components of the sub-clutch to move in order to establish a frictional engagement.

[0015] To actuate the first and / or second partial clutch, the first actuating lever is preferably operatively connected to the first pressure plate by means of a first transmission element, and the second actuating lever is operatively connected to the second pressure plate by means of a second transmission element. The function of the first and second actuating levers is, in each case, to transmit a compressive or tensile force exerted on the first or second actuating lever to the first or second pressure plate, respectively. If a compressive force is applied by the actuating lever, the corresponding pressure plate is moved against the other components of the respective partial clutch, thereby establishing frictional engagement between the components of the respective partial clutch. If a tensile force is applied, the existing frictional engagement of the respective partial clutch is released.

[0016] A flywheel is a disc-shaped mass that is mounted on a rotating axis without imbalance. Among other things, a flywheel is used as an energy storage device for kinetic energy in the form of rotational energy and inertia, by storing its rotational motion with minimal friction loss for use when needed.

[0017] The housing projection is an area that is directly or indirectly connected to the housing. This area is designed to serve as a support for the return springs and to hold the ends of the return springs, which are located in or on the housing projection, in a fixed position relative to the rest of the housing.

[0018] The first and second clutch discs are rotating components relative to and within the housing, each featuring a radially external friction section. Preferably, the housing surrounds at least the first and second clutch discs, as well as the first and second pressure plates, coaxially with the axis of rotation. When the clutch is engaged, the respective friction sections of the first and second clutch discs engage with the friction surface of the flywheel or with a friction surface of the housing and the friction surface of the respective pressure plate, forming a frictional connection. Once this frictional connection is established, a torque is transmitted to the first and / or second clutch disc via the housing projection and / or the flywheel and the respective pressure plate.

[0019] The first and second pressure plates, arranged between the first and second clutch discs, are each disc-shaped and aligned coaxially with the axis of rotation. To engage or disengage the partial clutch, the first and second pressure plates can each be actuated by means of the first or second actuating lever, respectively. The first and second actuating levers are, in turn, preferably actuated by a first and a second actuating bearing.

[0020] Preferably, the first actuating lever is actuated by pushing through the first actuating bearing in the direction of the flywheel, and the second actuating lever is also actuated by pushing through the second actuating bearing in the direction of the flywheel. Thus, the actuation directions, i.e., the directions for moving the respective partial clutch from the disengaged to an engaged state, are identical.

[0021] Preferably, the opposing sides of the first and second pressure plates are separated from each other by a stop arranged on the housing in the direction of the axis of rotation. The stop is preferably in the form of a snap ring, which thus restricts or limits the movement of the first and second pressure plates along the axis of rotation. The first pressure plate has a friction surface on its side facing the first clutch disc for the friction section of the first clutch disc, and the second pressure plate has a similar friction surface on its side facing the second clutch disc for the friction section of the second clutch disc. Furthermore, the flywheel also has a friction surface for the friction section of the first clutch disc on its side facing the first clutch disc.On the side of the second clutch disc facing away from the second pressure plate, the housing is designed with a friction surface for the friction section of the second clutch disc. The friction surface is preferably formed on a housing projection in the direction of the flywheel. The stop is arranged within the housing such that, at least when in contact with the stop, the first and second pressure plates form an air gap between themselves and their respective clutch discs, and an air gap between each clutch disc and the friction surface on the housing or flywheel side. However, the stop is not limited to the form of a snap ring. Alternatively, and preferably, the stop can also be a shoulder with a smaller radius within the housing, which is preferably integrally connected to the housing.

[0022] To enable the first and second clutch components to disengage independently, the return springs are supported at one end on the side facing away from the flywheel against the housing projection and at their other end against the first or second actuating lever. When the first and second actuating bearings no longer exert a counterforce, the return springs continue to hold the first and second actuating levers against the retracting bearings. The first and second actuating levers thus follow the further return movement of the first and second actuating bearings. The first and second pressure plates then also move away from the friction surfaces of the flywheel or the housing projection, respectively, and thus towards each other, lifting themselves away from the first or second clutch disc.The maximum return movement of the first and second pressure plates is limited by the housing-fixed stop between the two pressure plates.

[0023] Preferably, the first and / or the second transmission element is designed as an eye bolt, wherein the first transmission element and the first pressure plate are operatively connected to each other by a forming element, and the second transmission element and the second pressure plate are connected to each other by a further forming element. An eye bolt is a bolt with a ring at one end for receiving, for example, a bearing pin, and the other end of the bolt has a thread. In principle, the first and second transmission elements are not limited to the design as eye bolts. Particularly preferably, the forming element and the further forming element are designed as nuts that are complementary to the thread of the first and second transmission elements.However, various designs are also conceivable for the connecting element, creating a form-fit, material-fit, and / or friction-fit connection between the first clutch disc and the first transmission element, as well as between the second clutch disc and the second transmission element. Furthermore, the connecting elements are also intended for adjusting the distance between the respective friction surface of the flywheel or the housing projection and the corresponding friction section of the first and second clutch discs.

[0024] Preferably, the housing and the flywheel are connected to each other in a rotationally fixed manner, so that the flywheel fulfills the function of both a flywheel and an end-face housing cover. Furthermore, the mass of the flywheel is increased by the components connected to it in a rotationally fixed manner, which increases its moment of inertia. A reduction in the mass of the actual flywheel, which is compensated for by the mass of the housing, is also preferred in order to save weight on the entire dual clutch.

[0025] Preferably, the first and second actuating bearings are designed as rolling bearings, with the second actuating bearing having a larger inner radius than the outer radius of the first actuating bearing. The first actuating bearing rests against the side of the inwardly facing end of the first actuating lever facing away from the flywheel. The second actuating bearing also rests against the side of the inwardly facing end of the second actuating lever facing away from the flywheel. The first and second actuating bearings are preferably designed as rolling bearings and thus each has an annular shape. Both the first and second actuating bearings are arranged coaxially with the axis of rotation and axially, one behind the other, and are also mounted to be axially displaceable.The first actuating bearing is positioned inwards towards the flywheel, relative to the second actuating bearing. The second actuating bearing has a larger radial extent than the first, and its inner radius is larger than the outer radius of the first. This allows the first and second actuating bearings to be slidably positioned relative to each other along the axis of rotation A. Consequently, opening or closing the first or second partial clutch is possible independently of opening or closing the other partial clutch. This also enables a compact design for the actuating bearings.

[0026] Furthermore, a reversing transmission is proposed, which includes a dual clutch as described here. The details and advantages revealed for the dual clutch can be applied and transferred to the reversing transmission, and vice versa.

[0027] The invention and its technical context are explained in more detail below with reference to the figures. It should be noted that the invention is not intended to be limited by the exemplary embodiments shown. In particular, unless explicitly stated otherwise, it is also possible to extract partial aspects of the situations explained in the figures and combine them with other elements and findings from the present description and / or figures. It should be noted in particular that the figures, and especially the depicted proportions, are only schematic. The same reference numerals denote the same objects, so that explanations from other figures can be consulted as needed. The figures show: Fig. 1: a schematic cross-section of the double clutch according to the invention in the installed state; Fig. 2: a schematic representation of a first partial clutch of the double clutch according to the invention; and Fig. 3: a schematic representation of a second partial clutch of the double clutch according to the invention.

[0028] Fig. 1Figure 1 shows a schematic cross-section of a dual clutch 1. This clutch consists of a flywheel 5, which is connected coaxially to its axis of rotation A to a third transmission shaft 4 in a rotationally fixed manner and at its radially outer and circumferential end to a rotating housing 10. The third transmission shaft 4 is preferably designed to connect a drive (not shown), preferably an internal combustion engine, directly to an auxiliary drive shaft (also not shown). Coaxially to the third transmission shaft 4, a first transmission shaft 2, designed as a hollow shaft, is rotatably mounted on the outer circumferential surface of the third transmission shaft 4 and is axially displaceable along the axis of rotation A. At the end facing the flywheel 5, the first transmission shaft 2 is rotationally fixed to a radially outwardly projecting first clutch disc 6.The first transmission shaft 2 is designed to engage the forward gear via the first clutch disc 6. Furthermore, a second transmission shaft 3 is rotatably mounted on the outer circumferential surface of the first transmission shaft 2, coaxially with the first and third transmission shafts 2, 4, and is axially displaceable along the axis of rotation A. The second transmission shaft 3 is shorter than the first transmission shaft 2 in the direction of the flywheel 5. The second transmission shaft 3 is designed to engage the reverse gear via the second clutch disc 7. Thus, the dual clutch 1 can be connected, in particular, to a reversing transmission of a motor vehicle, such as an agricultural machine, in which a direct change of direction of travel is achieved by switching between the first transmission shaft 2 and the second transmission shaft 3.Alternatively, the first transmission shaft 2 is designed to engage reverse gear via the first clutch disc 6 and the second transmission shaft 3 is designed to engage forward gear via the second clutch disc 7.

[0029] At the end of the second transmission shaft 3 facing the first clutch disc 6, the second transmission shaft 3 is rotationally fixed to a radially outwardly extending second clutch disc 7, wherein the first and second clutch discs 6, 7 have identical radial extents. A first pressure plate 40 and a second pressure plate 50 are arranged between the first and second clutch discs 6, 7. The first and second pressure plates 40, 50 are each designed as discs and arranged coaxially with the axis of rotation A, wherein the first and second pressure plates 40, 50 have a radial extension outwards and are each provided with a through-opening 42, 52 towards the axis of rotation A, through which the first, second and third transmission shafts 2, 3, 4 extend.The opposing sides of the first and second pressure plates 40, 50 are separated by a stop 60, in the form of a snap ring, which is attached to the housing 10 and arranged coaxially around the axis of rotation A. A first actuating lever 20 and a second actuating lever 30 are each pivotally mounted at one end on the housing 10, with each of the first and second actuating levers 20, 30 extending radially inwards towards the axis of rotation A from a respective pivot bearing 21, 31 on the housing 10. The other, inwardly facing end of the first and second actuating levers 20, 30 is pivotally mounted in the direction of the axis of rotation A and about the respective pivot bearing 21, 31. A first actuating bearing 80 rests on the side of the inwardly facing end of the first actuating lever 20 that is opposite the flywheel 5.A second actuating bearing 90 is also located on the side of the inwardly facing end of the second actuating lever 30 facing away from the flywheel 5. This is shown in Figure 1. Fig. 1 only one first and one second actuating lever 20, 30 each, however, a plurality of first and second actuating levers 20, 30 are preferably provided around the circumference of the housing 10.

[0030] The first and second actuating bearings 80, 90 are designed as rolling bearings and thus each have an annular shape. Both the first actuating bearing 80 and the second actuating bearing 90 are arranged coaxially with the axis of rotation A and axially, namely in the direction of the axis of rotation A, one behind the other, and are also each mounted to be axially displaceable. The first actuating bearing 80 is located inwards relative to the second actuating bearing 90 in the direction of the flywheel 5, with the second actuating bearing 90 having a larger radial extent than the first actuating bearing and its inner radius being larger than the outer radius of the first actuating bearing 80. Thus, the first and second actuating bearings 80, 90 are also arranged to be displaceable relative to each other along the axis of rotation A, either one above the other or within each other.Although not shown, the first and second actuating bearings, designed as rolling bearings, are each provided with an inner and an outer ring, the inner ring or the outer ring being supported on the first or second actuating lever 20, 30.

[0031] On the first actuating lever 20, a further pivot bearing 22 is provided radially inside opposite the pivot bearing 21, with one end of a first transmission element 23 being mounted on this further pivot bearing 22. The first transmission element 23 extends from the further pivot bearing 22 parallel to the axis of rotation A in the direction of the flywheel 5. The first transmission element 23 is designed as an eye bolt, the eye forming the receptacle for the further pivot bearing 22. The end of the first transmission element 23 facing away from the eye is designed as a bolt and is provided with an external thread. At the end facing the flywheel 5, the first transmission element 23 is positively and frictionally connected to the first pressure plate 40 by a form element 41 in the form of screw connections that are screwed onto the threaded section of the first transmission element 23.The first pressure plate 40 has a friction surface 43 on its side facing the first clutch disc 6, designed for a friction section 8 of the first clutch disc 6. Furthermore, the flywheel 5 also has a friction surface 5a for the friction section 8 of the first clutch disc 6 on its side facing the first clutch disc 6.

[0032] On the second actuating lever 30, a further pivot bearing 32 is provided radially outside the pivot bearing 31, with one end of a second transmission element 33 being mounted on this second pivot bearing 32. The second transmission element 33 extends from the second pivot bearing 32 parallel to the axis of rotation A in the direction of the flywheel 5. Like the first transmission element 23, the second transmission element 33 is designed as an eyebolt, with the eye forming the receptacle for the second pivot bearing 32. The end of the second transmission element 33 facing away from the eye is designed as a bolt and is provided with an external thread.At the end facing the flywheel 5, the second transmission element 33 is positively and frictionally connected to the second pressure plate 50 by a form element 51 in the form of screw connections that are screwed onto the threaded section of the second transmission element 33. The second pressure plate 50 is designed with its side facing the second clutch disc 7 as a friction surface 53 for a friction section 9 of the second clutch disc 7. The same applies to the first and second transmission elements 23, 33 and the form elements 41, 51 as was stated for the first and second actuating levers 20, 30: although the figure only shows two actuating levers 20, 30, several transmission elements 23, 33, corresponding to the number of lever elements 20, 30, are distributed around the circumference of the housing 10.Both the at least one first actuating lever 20 and the at least one second actuating lever 30 are moved in a common actuating direction 100 to actuate the respective partial clutch 1a, 1b. Both partial clutches 1a, 1b are normally disengaged, so that the actuation of the respective partial clutch 1a, 1b causes the corresponding partial clutch 1a, 1b to engage.

[0033] On the side of the second clutch disc 7 facing away from the flywheel 5, a housing projection 11 is formed on the housing 10, extending radially inwards and rotating around the axis of rotation A. The housing projection 11 has a friction surface 13 on the side facing the second clutch disc 7. Furthermore, the housing 10 with the associated housing projection 11 and the flywheel 5 are designed to prevent dirt from entering the dual clutch and are shaped to dissipate heat particularly quickly.

[0034] Furthermore, the housing projection 11 is provided on the side facing away from the second clutch disc 7 with receptacles 12 for return springs 70. The return springs 70 are supported at one end on or within the receptacles 12 on the housing projection 11 and at their other end on the first or second actuating lever 20, 30. Any designation is possible for the return springs 70, preferably in the form of compression springs, tension springs, or torsion springs. As indicated by the designation "first / s" or "second / s", the first partial clutch 1a is formed at least from the flywheel 5, the first clutch disc 6, the first pressure plate 40, the first transmission element 23, the first actuating lever 20, and the first actuating bearing 80.The second partial clutch 1b is formed at least from the housing projection 11, the second clutch disc 7, the second pressure plate 50, the second transmission element 33, the second actuating lever 30 and the second actuating bearing 90.

[0035] Fig. 2 Figure 1 shows a schematic representation of a first partial coupling 1a of the double coupling 1 according to the invention, omitting the second partial coupling 1b, to illustrate the operating principle of the device. As already explained in the preceding description, the first partial coupling 1a is formed at least from the elements labelled "first / s / n...", and the second partial coupling 1b is formed at least from the elements labelled "second / s / n...".

[0036] To create a frictional connection between the first clutch disc 6 and a friction surface 5a of the flywheel 5, or to engage the first clutch component 1a of the dual clutch 1, an actuating force is initially transmitted in the actuation direction 100, namely towards the flywheel 5, through the first actuating bearing 80 to the first actuating lever 20. The force, in the form of pressure, and the displacement, corresponding to the lever ratio, are then transmitted to the first pressure plate 40 via the first transmission element 23, which is an eyebolt. The first pressure plate 40 thus follows the lever movement and moves towards the friction surface 5a of the flywheel 5.Accordingly, the first clutch disc 6 is clamped between the friction surface 43 of the first pressure plate 40 and the friction surface 5a of the flywheel 5, whereby a torque transmission takes place from the third transmission shaft 4, which is non-rotatably connected to the flywheel 5, to the first transmission shaft 2 under frictional action.

[0037] To open the first partial clutch 1a and create an air gap between the flywheel 5 and the first clutch disc 6, the actuating force at the first actuating bearing 80 is reduced in the direction of the flywheel 5, causing the first actuating bearing 80 to move away from the flywheel 5. Initially, a friction lining spring (not shown) of the first clutch disc 6 moves the first pressure plate 40 back in the opposite direction to the flywheel 5 along the axis of rotation A. When the first clutch disc 6 no longer exerts a counterforce, the return spring 70 continues to hold the first actuating lever 20 against the retracting first actuating bearing 80. The first actuating lever 20 thus follows the further retraction of the first actuating bearing 80. The first pressure plate 40 then also moves back and lifts off the first clutch disc 6.The maximum return movement of the first pressure plate 40 is limited by the housing-fixed stop 60; thus, the maximum return movement of the first actuating lever 20 is also predetermined. The first partial clutch 1a is therefore designed as a normally disengaged (disengaged in the unactuated state) friction clutch, which is actuated by the first actuating lever 20.

[0038] Fig. 3Figure 1 shows a schematic representation of a second partial clutch 1b of the dual clutch 1 according to the invention, now with the first partial clutch 1a omitted, to illustrate the operation of the device. In order to also create a frictional connection between the second clutch disc 7 and the friction surface 13 of the housing projection 11, and also to engage the second partial clutch 1b of the dual clutch 1, an additional actuating force is exerted in the actuating direction 100, i.e., in the direction of the flywheel 5, pressing on the second actuating bearing 90 and thus on the second actuating lever 30. The actuating direction 100 is therefore oriented the same as for the first partial clutch 1a, or, to engage one of the partial clutches 1a, 1b of the dual clutch 1, the first and the second actuating bearings 80, 90 are oriented in the actuating direction 100 (cf. Figure 1). Fig. 1), i.e., displaced in the direction of the flywheel 5 along the axis of rotation A. Preferably, a movement in the opposite direction to the described movement is also possible with the same effect if the pivot bearings 21, 31 of the first and second actuating levers 20, 30 are adapted accordingly.

[0039] Through the second transmission element 33, the force and displacement are also transmitted to the second pressure plate 50 in the second partial clutch 1b according to the lever ratio. However, unlike the first partial clutch 1a, the second pressure plate 50 is pulled in the direction of the second actuating lever 30. The second pressure plate 50 therefore does not follow the lever movement or the actuating direction 100 of the second actuating lever 30 towards the flywheel 5, but rather moves away from the flywheel 5. Accordingly, after a certain distance, the second clutch disc 7 is pulled against the inside of the housing 10, or more specifically, against the housing projection 11. The transmitted actuating force clamps the second clutch disc 7 between the friction surface of the second pressure plate 50 and the friction surface 13 of the housing projection 11.Thus, a frictional effect is created here as well between the second clutch disc 7 and the housing projection 11, so that a torque transmission from the housing 10 connected to the flywheel 5 to the second transmission shaft 3 can take place.

[0040] The opening of the second partial clutch 1b of the dual clutch 1 occurs in the same way as the opening of the first partial clutch 1a. In order to also open the second partial clutch 1b and create an air gap between the housing projection 11 and the second clutch disc 7, the actuating force is applied to the second actuating bearing 90 in the direction of the flywheel 5, which is located in the Fig. 3 is not shown and in the Fig. 3 is formed to the left of the projection 60 (cf. Fig. 1The force is reduced so that the second actuating bearing 90 moves away from the flywheel 5. Initially, a lining spring (not shown) of the second clutch disc 7 moves the second pressure plate 50 back towards the flywheel 5 along the axis of rotation A. When the second clutch disc 7 no longer exerts a counterforce, the return spring 70 continues to hold the second actuating lever 30 against the retracting second actuating bearing 90. The second actuating lever 30 thus follows the further return movement of the second actuating bearing 90. The second pressure plate 50 then also moves back, but in the opposite direction towards the flywheel 5, and lifts off the second clutch disc 7. The maximum return movement of the second pressure plate 50 is limited by the housing-fixed stop 60, thus also determining the maximum return movement of the second actuating lever 30.The second partial clutch 1b is therefore designed as a normally disengaged (disengaged in the unactuated state) friction clutch, which is actuated by pressing the second actuating lever 30.

[0041] The overall arrangement of the dual clutch 1, consisting of the first and second partial clutches 1a, 1b, is a so-called safety clutch, in which both partial clutches 1a, 1b are disengaged in the unactuated state, i.e., not engaged, and therefore no torque transmission takes place. For both the first partial clutch 1a and the second partial clutch 1b, the actuation direction for engaging the two partial clutches 1a, 1b is oriented towards the flywheel 5, with the return springs 70, arranged between the housing projection 11 and the first and second actuating levers 20, 30, opposing the direction of actuation. In particular, the actuation of the first and second partial clutches 1a, 1b is compressive, whereby a compressive force is exerted on the respective first and / or second actuating lever 20, 30 via the first and second actuating bearings 80, 90 to engage the respective partial clutch 1a, 1b.To disengage the two partial clutches 1a, 1b, the first and second actuating levers 20, 30 must retract in the opposite direction. Reference symbol list

[0042] 1 Dual clutch 1a First partial clutch 1b Second partial clutch 2 First transmission shaft 3 Second transmission shaft 4 Third transmission shaft 5 Flywheel 5a Friction surface 6 First clutch disc 7 Second clutch disc 8 Friction section of first clutch disc 9 Friction section of second clutch disc 10 Housing 11 Housing projection 12 Mounts 13 Friction surface 20 First actuating lever 21 Swivel bearing 22 Second swivel bearing 23 First transmission element 30 Second actuating lever 31 Swivel bearing 32 Second swivel bearing 33 Second transmission element 40 First pressure plate 41 Molded element 42 Through opening 43 Friction surface 50 Second pressure plate 51 Molded element 52 Through opening 53 Friction surface 60 Stop 70 Return spring 80 First actuating bearing 90 Second actuating bearing 100 Direction of operation A pivot axis

Claims

1. A dual clutch (1) with an axis of rotation (A), comprising a first sub-clutch (1a) and a second sub-clutch (1b), wherein the first sub-clutch (1a) comprises, in the direction of the axis of rotation (A), a first pressure plate (40), a flywheel (5) and a first clutch disc (6) therebetween, wherein the first pressure plate (40) and the first clutch disc (6) are slidably mounted along the axis of rotation (A), wherein the second sub-clutch (1b) comprises, in the direction of the axis of rotation (A), a second pressure plate (50), a housing projection (11) fixedly connected to a housing (10) and a second clutch disc (7) therebetween, wherein the second pressure plate (50) and the second clutch disc (7) are slidably mounted along the axis of rotation (A), further comprising an actuating system with a first actuating lever (20) for pressing actuation of the first sub-clutch (1a) and a second actuating lever (30) for pressing actuation of the second sub-clutch (1b), and wherein at least two return springs (70) are supported with one end on the housing projection (11) and with their other end on the first actuating lever (20) or on the second actuating lever (30) and counteract the direction of actuation of the first and second actuating levers (20, 30) to engage the first and second sub-clutches (1a, 1b), characterised in that the first and the second sub-clutches (1a, 1b) are disengaged in the unactuated state.

2. The dual clutch (1) according to claim 1, characterised in that the housing (10) surrounds at least the first and second clutch discs (6, 7) and the first and second pressure plates (40, 50) coaxially to the axis of rotation (A).

3. The dual clutch (1) according to claim 1 or 2, characterised in that the first actuating lever (20) is operatively connected to the first pressure plate (40) by means of a first transmission element (23), wherein the second actuating lever (30) is operatively connected to the second pressure plate (50) by means of a second transmission element (33).

4. The dual clutch (1) according to any one of the preceding claims, characterised in that the first and / or the second transmission element(s) (23, 33) are designed as eye bolts.

5. The dual clutch (1) according to any one of the preceding claims, characterised in that the first transmission element (23) and the first pressure plate (40) are operatively connected to each other by a shaped element (41) and the second transmission element (33) and the second pressure plate (50) are operatively connected to each other by a further shaped element (51).

6. The dual clutch (1) according to claim 5, characterised in that the shaped element (41) and the further shaped element (51) are designed as nuts.

7. The dual clutch (1) according to claim 6, characterised in that the first actuating lever (20) is actuated by a first actuating bearing (80) and the second actuating lever (30) is actuated by a second actuating bearing (90).

8. The dual clutch (1) according to any one of the preceding claims, characterised in that the housing (10) and the flywheel (5) are non-rotatably connected to each other.

9. The dual clutch (1) according to claim 7, characterised in that the first actuating bearing (80) and the second actuating bearing (90) are designed as rolling bearings, wherein the second actuating bearing (80) has a larger inner radius than the outer radius of the first actuating bearing (90).

10. A reversing transmission comprising a dual clutch (1) according to any one of the preceding claims.