Advantageous exemplary embodiments explained below are illustrated in the drawings.
The drawings show, each in schematic diagrams,
FIG. 1 an inventive camshaft in which a first adjusting element of an adjusting mechanism is supplied with hydraulic fluid through hydraulic lines which communicate with hydraulic lines in a second abutment,
FIG. 2 an alternative embodiment if the camshaft from FIG. 1 with a pressure bearing disk.
According to FIG. 1, an axial end area of an adjustable camshaft 1 has an inside shaft 4 mounted in an outside shaft 2 so that it is rotatable via a hydraulic adjusting mechanism 3 arranged at the end. The two shafts 2 and 4 each have cams 5 and 6 fixedly connected to them for valve control of an internal combustion engine. The cams 5 are fixedly connected to the outside shaft 2 while the cams 6 are connected to the inside shaft 4 in a rotationally fixed manner via pinning 7. The pins 7 run through the outside shaft 2 so that an independent rotational movement of the inside shaft 4 with the cams 6 pinned to it is possible with respect to the outside shaft 2. To create a relative rotation between the inside shaft 4 and the outside shaft 2, the hydraulic adjusting mechanism 3 is provided, as mentioned above, a first and a second rotatable adjusting element 8 and 9 that are rotatable with respect to one another, each being connected to one of the two shafts 4 and 2, are provided there. The first adjusting element 8 is fixedly connected to the inside shaft 4 while the second adjusting element 9 is fixedly connected to the outside shaft 2. In addition, the outside shaft 2 is adjacent to the adjusting mechanism 3 and is fixedly connected to a first bearing ring 11 that supports at least the outside shaft 2 in a stationary first abutment 10.
According to the first alternative of the inventive camshaft 1, the first bearing ring 11 has two hydraulic channels 12 and 12′ which communicate at one end with hydraulic channels in the stationary first abutment 10 and at the other end with the second adjusting element 9 of the adjusting mechanism 3. The supply of hydraulic fluid to the second adjusting element 9 is accomplished here via hydraulic channels 12, 12′ arranged in the first bearing ring 11 and in the first abutment 10. Hydraulic fluid is supplied to the first adjusting element 8 of the adjusting mechanism 3 via hydraulic channels 12″ and 12′″ which are provided in a second abutment 13 arranged in a stationary position adjacent to the first abutment 10 and a second bearing ring 14 mounted on the former. The two hydraulic channels 12″ and 12′″ supplying hydraulic fluid to the first adjusting element 8 run radially to the camshaft 1 in the second abutment 13 and in the second bearing ring 14 and also run radially through the outside shaft 2 whereby the hydraulic channel 12″ runs between the inside shaft 4 and the outside shaft 2 up to the first adjusting element 8, while the hydraulic channel 12′″ runs coaxially and within the inside shaft 4. The supply of hydraulic fluid to the first adjusting element 8 of the adjusting mechanism 3 is thus separated from the supply of hydraulic fluid to the second adjusting element 9 and is shifted to another abutment 13 of the camshaft and/or the respective bearing ring 14. Accordingly, this relieves the stress on the situation with regard to installation space in the area of the first abutment 10 is relieved.
According to FIG. 1, the pinning 7 connecting the cams 6 to the inside shaft 4 runs across the hydraulic channel 12′″ running within the inside shaft 3 and would interrupt flow of hydraulic medium in same if the pinning did not have a through-opening 15 which is preferably aligned with the hydraulic channel 12′″ and across the longitudinal axis of the pinning 7. The through-opening 15 ensures unhindered flow of hydraulic fluid within the channel 12′″ and thus ensures a reliable supply of hydraulic fluid to the first adjusting element 8. It is also conceivable here for the through-opening 15 to be formed from a plurality of through-holes and/or openings running across the pins 7 so that an accurate alignment of the pins 7, which should ensure unhindered flow of hydraulic fluid through the through-opening 15, can be omitted.
In an alternative embodiment of the camshaft 1 according to FIG. 2, an adjusting mechanism 3 is again provided, having a first adjusting element 8 fixedly connected to the inside shaft 4 and a second adjusting element 9 fixedly connected to the first bearing ring 11 and the outside shaft 2. In contrast with FIG. 1, however, the bearing ring 11 in FIG. 2 has four hydraulic channels 12, 12′, 12″ and 12′″, two hydraulic channels 12 and 12′ communicating at one end with corresponding hydraulic channels in the first abutment 10 and at the other end communicating with the first adjusting element 8 via hydraulic channels 12 and 12′ arranged in/on the inside shaft 4. The two other hydraulic channels 12″ and 12′″ communicate at one end with hydraulic channels in the first abutment 10 via hydraulic channels running in a pressure bearing disk 16 and at the other end with the second adjusting element 9. The pressure bearing disk 16 serves to adjust an axial play of the camshaft 1 and is connected fixedly to the first abutment 10 via corresponding connecting means 17, e.g., screws. In this alternative embodiment, the problem of an exclusive axially adjacent channel guidance in the first abutment 10 is thus solved.
For both embodiments, it is true that a fixation mechanism 20 which secures the adjusting mechanism 3 on the camshaft 1 and seals the hydraulic channel 12′″ (see FIG. 1) or 12′ (see FIG. 2) tightly on one end axially, said hydraulic channel being arranged coaxially within the inside shaft 4.
According to FIG. 2, a first radial seal 18 is provided between the first bearing ring 11 and the pressure bearing disk 16, serving to seal the hydraulic channels 12″ and 12′″ that supply hydraulic fluid to the second adjusting element 9. On the other hand, a second radial seal 19 is provided between the inside shaft 4 and the outside shaft 2 to seal the hydraulic channels (12′″ in FIGS. 1 and 12′ in FIG. 2) that supply hydraulic fluid to the first adjusting element 8.
In general, the first bearing ring 11 and/or the second bearing ring 14 may be shrunk onto the outside shaft 2 and thereby fixedly connected to it.
All the features described in the description and characterized in the following claims may be essential to the invention either individually or when combined in any form with one another.
Patent Application
20070295296
