BRIEF DESCRIPTION OF THE DRAWINGS
The invention is subsequently described with reference to figures. These show the following in particular:
FIG. 1 illustrates the disposition of a shaft according to the invention in the form of a transmission input shaft in a transmission unit in a highly simplified illustration;
FIG. 2 illustrates the forming of the groove by the two elements, defining the shaft, in a detail view according to FIG. 1;
FIGS. 3
a and 3b illustrate possible embodiments of the design of the flange section at the tubular element in two views.
DETAILED DESCRIPTION
FIG. 1 illustrates in a schematic highly simplified view through a cutout from an axial sectional view of a force transmission unit 1 the disposition of a shaft unit 2 provided according to the invention in the form of a transmission input shaft 3. The power transmission device 1 comprises an input E and an output A, as well as a hydrodynamic component 4, which is provided in the depicted embodiment as a hydrodynamic speed-/torque converter, subsequently designated abbreviated as torque converter 5. Embodiments as a hydrodynamic clutch are also conceivable. The hydrodynamic torque converter 5 comprises a pump wheel P, which can be connected or coupled torque proof with the input E of the force transmission device 1, a turbine wheel T, which is coupled with the output A at least indirectly, this means directly, or through additional intermediary or functional elements, and at least one stator wheel L. The hydrodynamic torque converter 5 thus serves for converting speed and torque. Furthermore, the power transmission device 1 comprises a device for circumventing the hydrodynamic power transfer, which is also designated as lockup clutch 6. Thus, the lockup clutch 6 is disposed in parallel to the hydrodynamic component 4. The lockup clutch 6 thus serves for the circumvention of the power flow through the hydrodynamic component 4. This comprises a first, friction surface array 7, comprising at least one element having friction surfaces, wherein the friction surface array 7 is connected at least indirectly torque proof with the input E, or the pump wheel P, or the connection between pump wheel P and input E of the force transmission device 1, and can be brought into operative engagement through an operating device 10, with a second friction surface array 8, comprising at least one element bearing a friction surface. The second friction surface array 8 is thus connected torque proof at least indirectly with the output A, either directly, or through a coupling with the turbine wheel T, or through a device 38 for attenuating oscillations. The coupling of the turbine wheel T and the second friction surface array 8 to the output A is thus performed in the simplest case through a so-called drive hub 9. The output A is formed by the shaft unit 2, which simultaneously serves as a transmission input shaft 3 for a transmission unit, arranged subsequently to the force transmission unit 1, which, however, is not shown. The operation of the lockup clutch 6 is performed through the operating device 10, which preferably comprises an axially movable piston element 11, which is supported movable in axial direction, depending on its coupling with an element connected torque proof to the input of the force transmission unit 1, or its connection with the pump wheel P, or the transmission input shaft 3, or the turbine wheel hub 9. The engineering design can be performed in various manners. The sliding movability is shown with a double arrow. Due to the disposition of the lockup clutch 6 in the housing of the force transmission device 1, which is formed by the housing 12 of the torque converter 5, which is formed in the simplest case by the pump wheel shell elements 12.1, 12.2, coupled with the pump wheel P, two chambers 14 and 15 are formed in the interior cavity 13, enclosed by the housing 12, which are divided in axial direction through the piston element 11. The control of the operation of the lockup clutch 6, in particular, of the friction engagement, is thus performed through adjustment of a pressure differential in the two chambers 14, 15, at least partially filled or flowed through by pressure medium, which are formed in the axial direction, respectively between the second friction surface array 8, or the piston element 11, and the housing 12 of the torque converter 5, and the piston element 11, or the face side of the piston element 11, facing the torque converter 5, and the torque converter 5. Thus, the piston element 11 is moved axially relative to the first and the second friction surface array 7, 8, when the pressure in the chamber 15 between housing wall and piston element 11 is higher than the pressure in the pressure chamber 14, and brings the friction surface arrays 7, 8 into mutual engagement. The magnitude of the pressure differential thus determines, if the lockup clutch 6 is operated with or without slippage. For conducting the operating medium and the cooling medium, which are not addressed here in detail, the connections 16 or 17 are associated with the chambers 14, 15. An additional connection, which is not shown here in detail, serves for coupling with the operating space of the torque converter 5.
The chamber 15 can be pressurized independently from the conditions in the torque converter 5, while the chamber 14 depends on the conditions in the torque converter 5. The particular chambers 14 and 15 are furthermore sealed against each other through a seal device 18, disposed between the transmission input shaft 3 and the housing 12. Furthermore, the pressure chamber 15, which is pressurized by the medium that transfers the operating pressure, is sealed relative to the adjacent oil channel, this means the connection 16 in the torque converter 5 through a seal device 18. The seal device 18 is thus provided between the transmission input shaft 3 and the output shaft 9. The coupling of the transmission input shaft 3 with the output shaft 9 thus forms the interface in the connection between the force transmission unit 1 and the transmission unit. The transmission unit in the illustrated embodiment has two channels 19, 20 disposed coaxial, which are used for carrying operating- or pressure media, in particular, in the form of oil. A first inner channel 19 is provided, which is enclosed by a second channel 20 in radial direction. The second outer channel 20 is thus connected with at least one, preferably a plurality of outlet openings 21, arranged in circumferential direction, which lead into the first pressure chamber 14, or which are connected with it. Thus, the particular outlet openings 21 are coupled at the shaft unit 2 in installed position with the operating cavity of the torque converter 5. The middle axes M of the particular outlet openings 21 are thus preferably disposed orthogonal, or at least at an angle with the center axis, and thus the rotation axis R of the transmission input shaft 3.
The seal device 18 is thus disposed in axial direction between the outlet openings 21 and the pressure chambers 15, 14. The shaft unit 2 therefore comprises a first hollow cylindrical element 22, forming the first channel 19. A second hollow cylindrical element 23 is furthermore provided, enclosing the first hollow cylindrical element in circumferential direction, forming the other second channel 20, wherein the first hollow cylindrical element 22 is coupled with the second one, 23, through a press connection 24. The first hollow cylindrical element is pressed into an axial end section 25, which protrudes from the second hollow cylindrical element 23, wherein the first hollow cylindrical element 22 has at least one protrusion 26, provided in radial direction in the end section 25 at the outer circumference, which protrusion 26 is offset in axial direction from a face side 36 of the second hollow cylindrical element 23, forming a groove 27 with it, with the seal device 18 being disposed in the groove 27.
FIG. 2 illustrates the embodiment, according to the invention, of the transmission input shaft 3 with integrated sealing device 18, based on a detail of FIG. 1. The input shaft 3, which comprises the two coaxially disposed channels 19, 20, is provided in at least two pieces for this purpose. The two channels 19, 20 are formed by the particular hollow cylindrical elements 22, 23. The second hollow cylindrical element 23 is provided in the form of a hollow shaft, which can be connected torque proof with the drive hub 9, depending on the embodiment. Thus, the interior circumference 28 of the second hollow cylindrical element 23 and the outer circumference 29 of the first hollow cylindrical element 22 determine the dimensions of the second channel 20. The other first channel 19, coaxially disposed to it, is provided by a first hollow cylindrical element 22, which is inserted into the hollow shaft in axial direction. The first hollow cylindrical element 22 is thus provided preferably in tubular form. It extends through the hollow shaft 23. Analogously, this applies for the channel 19 defined by the interior circumference 30. The first hollow cylindrical element 22 has a first section 31, a second section 32, and an end section 33, wherein the end section 33 belongs to the second section 32, forming the protrusion 25. The particular sections 31 and 32 are characterized through different dimensions in radial direction. The first section 31 forms a wall for the flow of operating fluid through the channel 20. Thus it has a smaller diameter than the interior diameter of the second hollow cylindrical element 23. The second partial area 32 serves to realize a press connection 24 with the second hollow cylindrical element 23, and it is adapted with respect to its outer diameter to the interior diameter of the second hollow cylindrical element, in order to form a press connection. The end section 33 forms the protrusion 25, the axial end section 25 forms the seal carrier. Therefore, the outer diameter in the second section 32 is provided with a press fit relative to the interior diameter of the second hollow cylindrical element 23 in this section. Through the press connection, the two channels 19 and 20 in the shaft unit 2 are provided mostly pressure and fluid tight.
The end section 33 protrudes in axial direction from the second hollow cylindrical element 23 with the end section 25. It has a preferably circumferentially extending ring- or flange shaped protrusion 34, forming a support surface for the seal unit 18 in axial direction on its axial surface 35, facing the second hollow cylindrical element 23. This surface 35 is disposed in installed position, offset in axial direction from the front face 36 of the second hollow cylindrical element 23, thus forming a groove 27 with it, and the outer circumference of the second section 32, extending in this area.
In order to avoid that the groove 27, required for the seal device 18 on the outer circumference 37 of the second hollow cylindrical element 23 of the transmission input shaft 3, leads to an unnecessary weakening of the cross section of the transmission input shaft 3, in particular, of the second hollow cylindrical element 23, provided in the form of the hollow shaft, in the area where the seal device 18 is located, according to the invention, the connection of the second hollow cylindrical element 23 to the first hollow cylindrical element 22 is performed in axial direction, so that the groove 27 is formed. The groove 27 is thus not only machined into the outer circumference 37, thus of the second hollow cylindrical element 23, but it is limited in axial direction by the first and the second hollow cylindrical element 22, 23. The diameter, in particular, the interior diameter, di27 of the groove 27, is thus determined by the outer diameter dA22 of the first hollow cylindrical element 22, in particular, of the tube. Thus, it is required that the tube in its axial end section 25 has at least a protrusion 26 extending in radial direction from the outer circumference 29 of the tube, and extending at least partially in circumferential direction, preferably, a circumferential annular protrusion 34, provided as an annular flange 37. It forms the surface 35, facing the first section 31, or the side surface of the groove 27, with its elements disposed in mounted position in axial direction with an offset between the first and the second hollow cylindrical element 22, 23, forming the groove 27, while the face side 36 of the second hollow cylindrical element 23 forms the second axial defining surface of the groove 27. The seal device 18 is thus fixated in axial direction between the two hollow cylindrical elements 22 and 23 with respect to its position. The groove 27 is thus formed quasi by a tubular flange with the face side of the transmission input shaft 3. This solution permits that the seal device 18 can be mounted on the tube before pressing it in. Thus it is not required to stretch the seal device 18 over the outer shaft diameter of the transmission input shaft 3, in particular of the hollow shaft, during assembly. Thus it is possible, in particular, also to use closed seal elements for outer shaft diameters in the range of more than 20 mm, wherein no particular requirements with respect to the material exist. The groove 27 does not have to be machined anymore, but it is defined through the positioning of the tube, this means the hollow cylindrical element 22 and 23 in axial direction. The end area of the transmission input shaft 3 can be provided with small wall thickness, when provided as a hollow shaft, without additional consideration for the placement of the sealing device 18.
According to a particularly preferred embodiment, the flange 37 at the end section 25 of the tube 27 can additionally take over a sealing function in axial direction. In this case, the flange area 37 in circumferential direction is provided completely circumferential at the end section 25. This flange 37 defines a seal surface 39, or a seal surface area with its face side 38 facing away from the groove 27, while the surface 39 at the flange 37 is being used only partially. The flange 37 can form a sealing pair with the complementary surface areas, wherein the flange abuts to respective surface areas of connection elements in axial direction in a sealing manner, or wherein it is coupled with these respective elements. The forming of a flange 37 with sealing function with a flange surface, extending in circumferential direction in the end section 25 of the first hollow cylindrical element 22, in particular of the tube, is depicted in an exemplary manner in a view from the front in the FIG. 3a in both views for the first hollow cylindrical element 22.
According to a refinement, the flange 37 can also be provided without sealing function. Thus, the particular flange sections can be formed through protrusions 26.1 through 26.3, which are formed in radial direction, and which partially extend in circumferential direction, formed as flange segments 37.1 through 37.n. In this case, the function of the flange 37 is only the formation of a lateral support, or support area sections for the seal device 18. Such an embodiment is shown in two views in FIG. 3b.
The double arrows in the figures illustrate motion- or flow directions.
DESIGNATIONS
1 force transmission device
2 transmission unit
3 transmission input shaft
4 hydrodynamic component
5 hydrodynamic speed-/torque converter
6 device for circumventing the power transmission at the hydrodynamic component
7 first friction surface array
8 second friction surface array
9 drive hub
10 actuation device
11 piston element
12, 12.1,
12.2 torque converter housing
13 interior space
14 pressure chamber
15 pressure chamber
16 connector
17 connector
18 seal device
19 channel
20 channel
21.1-21.n outlet opening
22 first hollow cylindrical element
23 second hollow cylindrical element
24 press connection
25 end section
26 protrusion
27 groove
28 inner circumference
29 outer circumference
30 inner circumference
31 first section
32 second section
33 end section
34 protrusion
35 surface
36 front face
37 flange
37.1-37.n flange segment
38 face side
39 seal surface
- di27 inner diameter of groove
- dA22 outer diameter of first hollow cylindrical element
Patent Application
20080083593
