Patent Application
20210156465
The present application is related and has right of priority to German Patent Application No. 102019217982.7 filed on Nov. 21, 2019, which is incorporated by reference in its entirety for all purposes.
The invention relates generally to a transmission for a motor vehicle, and to a motor vehicle including such a transmission.
A transmission is described in DE 10 2016 217 242 A1. A housing of this transmission encloses a cavity, and an oil pan is connected to the housing. In the exemplary embodiment according to
Example aspects of the invention further develop the transmission known from the prior art.
In example embodiments, a transmission for a motor vehicle is provided. The transmission includes a housing and a gear set enclosed by the housing. The gear set is configured for making different transmission ratios available between an input shaft and an output shaft of the transmission. The gear set can be formed, for example, by multiple spur gear trains and/or by planetary gear sets. The transmission includes a hydraulic system, which supplies oil to the gear set for lubrication. Lube oil supplied to the gear set collects in an oil sump of the transmission due to gravity. The hydraulic system includes a pump, which scavenges oil out of the oil sump and supplies the oil to the gear set and, if necessary, to further hydraulic consumers of the transmission.
An oil drainage channel is formed by the housing and/or by an element connected to the housing. The oil drainage channel is arranged spatially underneath the gear set and includes at least one gear set-side inlet port, a closed underside, and an oil sump-side outlet port at one end of the oil drainage channel. The oil drainage channel is arranged and designed such that oil from the gear set enters the drainage channel through the at least one inlet port and is guided along the closed underside of the oil drainage channel to the outlet port. A suction port of the hydraulic system arranged in the oil sump is arranged spatially underneath the closed underside of the oil drainage channel and axially offset with respect to the outlet port. The term “axial” relates to the axis of rotation of the transmission input shaft in this case.
Due to such an arrangement, it is ensured that no air enters the suction port even upon strong acceleration of the motor vehicle including such a transmission. This is the case because, due to the closed underside of the oil drainage channel, oil cannot flow, unobstructed, out of the oil sump into the gear set during an acceleration process, and so more oil remains in the oil sump.
Preferably, the at least one inlet port is arranged axially offset with respect to the outlet port. The term “axial” relates to the axis of rotation of the transmission input shaft in this case. As a result, oil from the gear set can enter the oil drainage channel along a short path, and so the hydraulic drag of rotating parts of the gear set is reduced.
Preferably, the oil drainage channel includes multiple inlet ports. As a result, the oil flow from the gear set into the oil drainage channel can be affected in a targeted manner.
Preferably, the oil drainage channel includes an outlet port at only one single end. As a result, oil cannot flow, unobstructed, from the oil sump into the gear set during certain operating conditions of the motor vehicle, and so more oil remains in the oil sump.
Preferably, the closed underside of the oil drainage channel is formed, at least partially or in sections, by the hydraulic unit, which is connected to the housing. As a result, the housing, which is usually manufactured by casting, is more easily manufactured.
According to one preferred example embodiment, the housing includes a housing wall, wherein the outlet port is arranged spatially directly under the housing wall. The housing wall can be arranged between the gear set and a cavity of the transmission positioned upstream from the gear set, wherein this upstream cavity is enclosed, at least partially or in sections, by the housing. This upstream cavity can accommodate, for example, an electric machine and/or a torque converter, wherein one or both of these elements can be coupled to the input shaft of the transmission. This cavity can be designed as a wet space, wherein oil flowing out of the cavity collects in the oil sump due to gravity. An opening can be provided in the housing wall, in order to ensure a pressure compensation between the gear set space and the aforementioned cavity.
Preferably, the transmission for a motor vehicle is provided with a drive train aligned in parallel to the direction of travel of the motor vehicle, and so the input shaft and the output shaft of the transmission are aligned in parallel to the direction of travel.
One exemplary embodiment is described in detail in the following with reference to the figures. Wherein:
Reference will now be made to embodiments of the invention, one or more examples of which are shown in the drawings. Each embodiment is provided by way of explanation of the invention, and not as a limitation of the invention. For example, features illustrated or described as part of one embodiment can be combined with another embodiment to yield still another embodiment. It is intended that the present invention include these and other modifications and variations to the embodiments described herein.
Of course, the invention is not limited to a transmission G for such a drive train configuration. The transmission G could be utilized, for example, in an all-wheel drive train or in a drive train having front-wheel drive. Alternatively or additionally, the internal combustion engine VM and/or the transmission G could be arranged in the area of the vehicle rear axle, or even between the front axle and the rear axle.
The housing GG includes a housing wall ZP. The housing wall ZP separates the gear set RS from a cavity G1 of the transmission G. The cavity G1 is delimited, at least partially or in sections, from the housing GG. A torque converter TC including an impeller PR, a turbine wheel TR, and a stator LR is arranged in the cavity G1. The impeller PR is connected to a connection shaft AN. A crankshaft of the internal combustion engine VM can be connected to the connection shaft AN, if necessary, by an interposed unit for reducing torsional vibrations (not represented in
Moreover, an electric machine EM including a stator ST and a rotor RO is arranged in the cavity G1. The stator ST is attached at the housing GG in a rotationally fixed manner. The rotor RO is connected to the connection shaft AN. This arrangement is to be considered merely as an example. Alternatively, the rotor RO could be connected to the input shaft GW1. The electric machine EM could also be entirely omitted.
The cavity G1 forms a wet space. Oil flowing out of the cavity G1 collects in the oil sump S due to gravity. An opening ZPA is provided in the housing wall ZP, in order to ensure a pressure compensation between the gear set space and the cavity G1.
The housing GG, together with the hydraulic unit HY attached at the housing GG, forms an oil drainage channel D underneath the gear set RS. The oil drainage channel D includes three inlet ports DE1, DE2, DE3, a closed underside DL, and an outlet port DA. The outlet port DA is arranged directly under the housing wall ZP and axially offset with respect to the inlet ports DE1, DE2, DE3. The suction port OF of the hydraulic unit HY is arranged spatially underneath the closed underside DL and axially offset with respect to the outlet port DA.
In
For such a mode of operation, a complete seal between the rear gear set space and the rear area of the oil sump S is advantageous, but is not a precondition. If a complete seal is not possible, an oil flow from the rear area of the oil sump S into the rear gear set space can be decelerated, for example, with the aid of a labyrinth formation and an intentional reduction of the gap dimensions. This is generally sufficient, since such strong acceleration processes do not last for a long time period.
The proportions represented in the figures are utilized only for the purpose of illustration, and are not to be considered to be full scale.
Modifications and variations can be made to the embodiments illustrated or described herein without departing from the scope and spirit of the invention as set forth in the appended claims. In the claims, reference characters corresponding to elements recited in the detailed description and the drawings may be recited. Such reference characters are enclosed within parentheses and are provided as an aid for reference to example embodiments described in the detailed description and the drawings. Such reference characters are provided for convenience only and have no effect on the scope of the claims. In particular, such reference characters are not intended to limit the claims to the particular example embodiments described in the detailed description and the drawings.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2019 217 982.7 | Nov 2019 | DE | national |
