Patent Application
20070267270
To return to the torsion damper hub 20 of the takeoff-side transmission element 22, this hub has a set of teeth 21 by which it engages nonrotatably but with freedom of axial movement with a bearing journal 23 of a coupling arrangement 25, which, as will be explained again in more detail later, has a first clutch device 24 and a second clutch device 54.
The bearing journal 23 of the coupling arrangement 25 carries on its radially outer side a bearing 32, by which the bearing journal 23 is to be centered by means of a partition wall 26 on a gearbox housing 42 of a gearbox 43. The partition wall 26 is supported for this purpose by way of a radially outer seal 34 against an inner wall of the gearbox housing 42 and by way of a radially inner seal 33 against the outside diameter of the bearing journal 23. The partition wall separates an essentially dry surrounding space 30, through which a shaft 31 of a drive train can be suitably passed, from a wet space 143, which is located on the other side of the partition wall 26 and which serves to hold the two clutch devices 24 and 54 of the coupling arrangement 25 and also to hold an electric machine 44. This machine has a stator 45, which is fastened by a retainer 48 to an inside wall of the gearbox housing 42, and which acts by way of a gap 47 on a rotor 46. The rotor 46, like the torsional vibration damper 7, the crankshaft 2 of the internal combustion engine 1, the bearing journal 23 of the coupling arrangement 25, and a takeoff 35 in the form of a gearbox input shaft 36, rotate around an axis of rotation 37, which is at least essentially the same for all of the previously mentioned components. It should also be observed here supplementally that the end of the bearing journal 23 facing the gearbox input shaft 36 is provided with a recess 41, in which the free, drive-side end of the gearbox input shaft 36 engages axially. The input shaft is centered here by a radial bearing 40, which serves as a pilot bearing, on the bearing journal 23 and thus on the gearbox housing 42.
At the end facing away from the crankshaft 2, the bearing journal 23 is connected nonrotatably to a first drive-side clutch element carrier 27 and can therefore be considered functionally a part of this first drive-side clutch element carrier 27. The radially outer area of the clutch element carrier 27 is connected nonrotatably by way of a set of teeth 28 to radially inner first clutch elements 67 of the first clutch device 24. These radially inner first clutch elements 67, which are in the form of inner plates, are moved into working connection with radially outer first clutch elements 68 in the form of outer plates when a first piston 72 of the first clutch device 24 exerts axial pressure on the first clutch elements 67, 68 in the direction toward the partition wall 26. As a result of this pressure, the first clutch elements 67, 68 come to rest axially against each other under the effect of friction and thus form a friction area 69. Ultimately, the first clutch element 67 closest to the partition wall 26 comes to rest by way of the last plate 90 against an axial backup ring 91, which is stationary with respect to the first drive-side clutch element carrier 27. When, however, the axial pressure being exerted by the piston 72 on the first clutch elements 67, 68 is released, the frictional effect present in the friction area 69 at least partially disappears. In this latter state of the piston, the first clutch device 24 is in its released position, whereas, when the piston 72 is exerting axial pressure on the first clutch elements 67, 68, the first clutch device 24 is in its engaged position. Thus the piston 72 and the first clutch elements 67, 68 together form the clutch components 85 of the first clutch device 24.
The radially outer first clutch elements 68 are connected for rotation in common by a set of teeth 77 to a first takeoff-side clutch element carrier 50 of the first clutch device 24, the carrier being connected nonrotatably to a second drive-side clutch element carrier 51 of the second clutch device 54. The second drive-side clutch element carrier 51 consists of an at least essentially radial drive-side radial housing wall 53 and an axial housing wall 55, which is formed in the radially outer area of the radial housing wall 53. The free, takeoff-side end of this axial housing wall 55 holds another takeoff-side radial housing wall 56 in nonrotatable, sealed fashion, which cooperates with the drive-side radial housing wall 53 and the axial housing wall 55 to form the clutch housing 60 of the second clutch device 54, which is at least essentially sealed off from the wet space 143 and from the gearbox housing 42.
Before the second clutch device 54 is discussed in detail, it should first be pointed out that the first takeoff-side clutch element carrier 50 and the second drive-side clutch element carrier 51 together form a coupling element 61 of the coupling arrangement 25. This coupling element 61 is an essential feature which makes it possible to design the coupling arrangement 25 as a clutch module 145.
The second drive-side clutch element carrier 51 is connected nonrotatably by a set of teeth 57 to radially outer second clutch elements 93, which can be brought into working connection with radially inner second clutch elements 92 by way of a friction area 70, where the radially inner second clutch elements 92 are connected nonrotatably to a second takeoff-side clutch element carrier 103 of the second clutch device 54 by a set of teeth 58. The second clutch device 54 is in its engaged position when the piston 94 is exerting axial pressure on the second clutch elements 92, 93 by way of a contact-mediating energy storage device 100, which is intended to make the engagement process proceed more “softly”, so that the second clutch elements 92, 93 come to rest by way of the last plate 107 against an end stop 106 on the drive-side radial housing wall 53. The second clutch device 54 is in its released position, however, when the axial force exerted by the piston 94 is reduced to such an extent that the frictional effect present in the friction area 70 between the second clutch elements 92, 93 has at least essentially disappeared.
The radially inner area of the coupling element 61, specifically of its drive-side radial housing wall 53, is connected nonrotatably to a coupling element hub 62, which is centered with respect to the gearbox input shaft 36 by a bearing 64 and positioned axially by means of another bearing 71 versus the first drive-side clutch element carrier 27 and thus versus the bearing journal 23 of the coupling arrangement 25. The coupling element hub 62 for its own part centers the hub 104 of the second takeoff-side clutch element carrier 103 by means of another bearing 65.
The first clutch device 24 has a pressure space 75, the boundaries of which are formed by the piston 72 on one side and by the drive-side radial housing wall 53 of the second clutch device 54 on the other. This pressure space is sealed off by seals 73, 74 against a first cooling space 76, in which the first clutch elements 67, 68 are located. This cooling space 76 holds an axial energy storage device 80, which is formed preferably by a stack of two springs, and which is supported at one end against the piston 72 and at the other end against a retainer 162 permanently connected to the coupling element hub 62. The axial energy storage device 80 serves to exert force on the piston 72 in the direction toward the drive-side radial wall 53 of the second clutch device 54. The goal of this measure is to prevent the piston 72 from making undesirable contact with the first clutch elements 67, 68 when in the disengaged position and thus to avoid the occurrence of undesirable torque transmission by the first clutch device 24.
As a result of the rotation of the coupling arrangement 25 around the axis of rotation 37, fluid medium present in the cooling space 76 is accelerated radially outward. It then passes through flow passages 86 in the first drive-side clutch element carrier 27 and thus efficiently cools the friction area 69 of the first clutch device 24. After passing through the friction area 69, the fluid medium arrives via the set of teeth 77 of the first takeoff-side clutch element carrier 50 in a discharge route 144, which leads farther outward in the radial direction and which is part of the wet space 143. The fluid can thus return via this discharge route 144, which extends as much as possible within the gearbox housing 42, to a fluid reservoir 141, illustrated in merely schematic fashion.
As
The second clutch device 54 also has a pressure space 97, located axially between the piston 94 and the adjacent takeoff-side radial housing wall 56 of the clutch housing 60, for which reason the piston is separated radially on the outside and radially on the inside by seals 95, 96 from a cooling space 98, in which the second clutch elements 92 and 93 are located, which act jointly with the piston 94 as clutch components 146 of the second clutch device 54. The piston 94 is mounted with freedom of axial movement on a clutch housing hub 63 of the clutch housing 60 of the second clutch device 54, where the clutch housing hub 63 and a stationary support shaft 110, which is designed as a hollow shaft, form the radial boundaries of a first ring-shaped channel 111, whereas the support shaft 110 for its own part and the gearbox input shaft 36 form the boundaries of a second ring-shaped channel 112. Finally, a central bore 113 is provided in the gearbox input shaft 36; this bore is sealed off on the drive side by a plug 114, which is inserted into the end of the bore.
To return to the clutch housing hub 63, a line 116 passes through the hub. This line opens out into the pressure space 97 of the second clutch device 54 and is connected to a line 115 in the gearbox 43, where the line 115 is connected to the previously mentioned infeed line 147 of the open-loop and/or closed-loop control unit 136. The lines 115 and 116 possibly together with the infeed line 147 form a first supply line 120, through which the pressure space 97 of the second clutch device 54 is filled with fluid medium.
A second supply line 121 is created on the basis of the first ring-shaped channel 111 and possibly the infeed line 133 and serves to connect the cooling space 98 of the second clutch device 54 to the open-loop and/or closed-loop control unit 136. Fluid medium flows from the second supply line 121 radially outward, whereupon it flows through the flow passages 99 present in the second takeoff-side clutch element carrier 103 to supply the friction area 70 of the second clutch device 54. After flowing through this friction area 70, the fluid medium is deflected radially inward again at the set of teeth 51 of the second drive-side clutch element carrier 51, and then flows radially inward, arriving in an axial area between the drive-side radial housing wall 53 of the clutch housing 60 and the second takeoff-side clutch element carrier 103, this area extending all the way to the hub 104 of the carrier. Once there, the fluid passes through the bearing 65 at least essentially in the axial direction. Then the fluid medium passes through another line 130, which acts as a connecting line 131, formed in the coupling element hub 62 and shown in broken line, and arrives in the cooling space 76 of the first clutch device 24, where, in the manner previously described, the fluid medium arrives at the friction area 69 of this clutch device 24 via the flow passages 86. In contrast to the cooling space 98 of the second clutch device 54 closer to the supply source 140, the cooling space 76 of the first clutch device 24 farther away from the supply source 140 is not supplied with fresh fluid medium from the supply source through its own separate supply line but rather merely via the connecting line 131 leading to the cooling space 98 of the second clutch device 54. As a result, one of the supply lines can be eliminated, but this is uncritical, because both clutch devices 24 and 54 rotate around the axis of rotation 37 and thus bring about an enormous amount of circulation and therefore of mixing of the fluid medium inside the cooling space 98 of the second clutch device 54. As a result, it is guaranteed that the fluid medium which has been sent onward by the connecting line 131 to the cooling space 76 of the first clutch device 24 is sufficiently cool and is therefore still fully capable of fulfilling its intended function in the first clutch device 24 as well.
Only a portion of the fluid medium flowing radially inward between the drive-side radial housing wall 53 and the second takeoff-side clutch element carrier 103 arrives via the bearing 65 and the connecting line 131 at the cooling space 76 of the first clutch device 24. The remaining portion of this fluid medium flows through a line 123 provided in the hub 104 of the second takeoff-side clutch element carrier 103 and thus arrives in the second ring-shaped channel 112, so that the line 123 and the second ring-shaped channel 112 and possibly the outfeed line 135 together form a discharge line 122 for the second clutch device 54. The departing fluid medium arrives via the outfeed line 135 at the open-loop and/or closed-loop control unit 136, and from there it returns to the fluid reservoir 141. From there, possibly after intermediate cooling, the fluid medium can be sent back through the connecting line 142 to the supply source 140 and is thus available again to the infeed lines 133, 134, and 147 for filling the supply lines 120, 121, and 126.
In conclusion it remains to be said that the second clutch device 54 also has an axial energy storage device 101, which for its own part is supported on one side against the piston 94 and on the other side against a backup ring 102, recessed into the clutch housing hub 63, and which exerts force on the piston 94 in the direction away from the clutch elements 92, 93. In the case of the second clutch device 54 as well, the purpose of the axial energy storage device 101 is to prevent undesirable friction between the clutch elements 92, 93 after the clutch device 54 has been released.
Of course, the individual supply lines 120, 121, and 126 must be isolated from each other in a leakproof manner, for which reason seals 132a to 132e are provided at the appropriate points. Specifically, there are first seals 132a and 132b, which are located radially between the coupling element hub 62 and the gearbox input shaft 36, which is centered versus the coupling element hub 62 by at least one bearing 64. There is also a second seal 132c, located radially between the support shaft 110 and the hub 104 of the takeoff-side clutch element carrier 103, this hub executing only slight radial movement relative to this support shaft 110. Finally, there are the third seals 132d and 132e, located radially between the clutch housing hub 63 and the gearbox housing 42 of the gearbox 43, where the clutch housing hub 63 is centered versus the gearbox housing 42 by at least the bearing 66.
Thus, while there have shown and described and pointed out fundamental novel features of the invention as applied to a preferred embodiment thereof, it will be understood that various omissions and substitutions and changes in the form and details of the devices illustrated, and in their operation, may be made by those skilled in the art without departing from the spirit of the invention. For example, it is expressly intended that all combinations of those elements and/or method steps which perform substantially the same function in substantially the same way to achieve the same results are within the scope of the invention. Moreover, it should be recognized that structures and/or elements and/or method steps shown and/or described in connection with any disclosed form or embodiment of the invention may be incorporated in any other disclosed or described or suggested form or embodiment as a general matter of design choice. It is the intention, therefore, to be limited only as indicated by the scope of the claims appended hereto.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2006 023 289.5 | May 2006 | DE | national |
