Patent Application
20090075778
This application claims priority from German Application Serial No. 10 2007 044 782.7 filed Sep. 19, 2007.
The invention concerns the connection of a planetary gear drive with the spur gear and/or central gear in an automatic transmission.
The Applicant's DE 103 33 437 A1 discloses a multi-speed automatic transmission, comprising an input shaft, an output shaft, three single planetary gearsets arranged side by side in a row, as well as five shifting elements. In the known transmission, a sun gear of the third gearset can be fixed on a transmission via the first shifting element. The drive shaft is furthermore connected to a sun gear of the second gearset and can be connected via the second shifting element to a sun gear of the first gearset and/or via the fifth shifting element to a carrier of the first gearset. As an alternative to this arrangement, the sun gear of the first gearset can be fixed on the transmission housing via the third shifting element and/or the carrier of the first gearset can be fixed on the transmission housing via the fourth shifting element. It is also provided to connect the input shaft to a ring gear of the first gearset and one of the carriers of the second or third gearset, wherein the second and fifth shifting element form an assembly, each having one disc set and one servo device, as well as one disc carrier for both shifting elements, wherein the disc set of the second shifting element has a larger diameter than the disc set of the fifth shifting element.
From DE 10 2004 050 123 A1 a power shift transmission is known with three planetary gearsets, which is selectively controlled via five torque transmission mechanisms to establish six forward speed ratios and one reverse speed ratio for the transmission. The torque transmission mechanisms comprise piston mechanisms, which can be displaceably arranged in elements of the transmission housing, which comprise a front-end cover, a rear-end cover and a shell that connects the front-end cover and the rear-end cover. The output of the planetary gear drive is also carried out via a carrier of the planetary gearset in the transmission according to DE 10 2004 050 123 A1.
It is further known that the output of the planetary gear drive can be carried out via a ring gear, wherein the ring gear is axially fixed on the spur gear via an intermediate ring.
It is an object of the invention to provide a connection of a planetary gear drive with a spur gear in an automatic transmission, such that the engagement of the intermediate gear ratio is optimized and a reduction in weight of the bearing plate can be achieved. A material conversion of the bearing plate to cast iron should in particular be made possible.
The stress to the housing caused by the number of bolts should also be reduced. It is another object of the invention to reduce the production and assembly costs and to improve the noise behavior, as well as the load capacity of the gearing and bearing.
Accordingly, in order to improve the engagement and reduce the stress on the components, it is proposed to realize an internal equilibrium of the axial forces. This is achieved by counteracting the axial force of the central spur gear with the axial force from the planetary gear drive.
An equilibrium of forces in an axial direction is at least approximately realized by adjusting the directions and size of the helix angle. According to the invention, the axial force input from the planetary gear drive and the output of the planetary gear drive can be carried out by way of the ring gear, sun gear, sun gear shaft, planetary carrier or carrier shaft, while the spur gear should preferably be axially braced in both load directions. The equilibrium of forces takes place in traction as well as in coasting mode.
The element of the planetary gear drive, which is connected to the spur gear, can be axially secured or braced by way of two locking rings, one locking ring and one bearing area, other non-positive or positive locking elements or a concealed snap-in locking element. The bearing area can be designed herein as an axial contact surface or as an axial bearing area. The support can preferably be carried out via contact areas combined with locking elements.
A locking ring which accommodates axial loads in two directions can be used within the scope of a preferred further development of the invention.
According to the invention, the diameter of the axial force transmission is preferably within a comparable order of magnitude, such as the diameter of the gearing of the spur gear.
A connection of a planetary gear drive with the spur gear in an automatic transmission is made available by way of the design, by way of which the stress on the surrounding components, such as the bearing plate, bearing and screw connection is kept to a minimum. The inclination and deflection of all the parts is additionally reduced. The tilting between the running gears is particularly minimized. The necessary axial installation space as well as the weight, are preferably reduced.
The invention will now be described, by way of example, with reference to the accompanying drawings in which:
In the exemplary embodiment shown in
The diameter of the axial force transmission can be within a comparable order of magnitude, such as the diameter of the gearing of the spur gear 2, as shown in
The element of the planetary gear drive or the planetary gear drive connected to the spur gear 2 can also be axially braced by way of two locking rings 4, 4′, as shown in
The output carrier can also be axially secured by way of the locking ring 6 and the axial contact area 7, as shown in
The object of
| Number | Date | Country | Kind |
|---|---|---|---|
| 102007044782.7 | Sep 2007 | DE | national |
