Patent ID: 12240308

DETAILED DESCRIPTION

The Figures are merely schematic representations and serve only to illustrate examples of the disclosure. Identical or equivalent elements are in principle provided with the same reference signs.

FIG.1shows a vehicle10which is an electric vehicle in the present example.

The vehicle10comprises a pair of front wheels12and a pair of rear wheels14.

The rear wheels14are driven wheels. The left rear wheel14may be called a first wheel and the right rear wheel may be called a second wheel14.

To this end, an axle assembly16is provided.

The axle assembly16comprises a first electric machine18and a second electric machine20.

Moreover, the axle assembly16comprises a spur gear unit22having a spur gear stage24and a differential gear unit26.

The axle assembly16is shown in more detail inFIG.2.

As can be seen therefrom, the first electric machine18comprises an internal stator28and an external rotor30.

Also, the second electric machine20comprises an internal stator32and an external rotor34.

In the example shown in the Figures, the first electric machine18and the second electric machine are of the same type.

An output shaft of the first electric machine18and an output shaft of the second electric machine20are formed by a common shaft36.

At the same time, the common shaft36is an input shaft of the spur gear stage24.

The common shaft36is supported on a housing38of the axle assembly16via exactly two bearing units40,42.

Moreover, a singular pinion44is arranged on the common shaft36. The singular pinion44is rotationally fixed on the common shaft36.

The spur gear stage24additionally comprises an intermediate shaft46.

The intermediate shaft46is arranged in parallel to the common shaft36.

The intermediate shaft46and the common shaft36are offset from one another.

Also, the intermediate shaft is rotatorily supported on the housing38via exactly two bearing units48,50.

A first gear52and a second gear54are rotationally fixed on the intermediate shaft46.

The first gear52engages the singular pinion44.

Thus, the first gear52and the singular pinion44form the spur gear stage24.

The spur gear stage24is coupled to the differential gear unit26via the second gear54. In other words, the spur gear stage24is drivingly connected to the differential unit26.

To this end, the second gear54engages a ring gear56of the differential gear unit26.

It is noted that in the present example the second gear54engaging the ring gear56is seen as a connection between the spur gear stage24and the differential gear unit26rather than a second spur gear stage.

In the present example, the ring gear56is fixed on a cage58of the differential gear unit26. Moreover, inside the cage58, a total of four bevel gears60are provided.

Since the differential gear unit26structurally corresponds to a generally known differential gear units, a detailed description of the interaction of the cage58, the four bevel gears60and the ring gear56is omitted here.

The cage58, or more generally speaking the differential gear unit26is rotatably supported on the housing38by exactly two bearing units62,64.

Thus, an axis of rotation of the differential gear unit26is parallel to the common shaft36.

Moreover, the differential gear unit26comprises a first output flange66being provided on the bevel gear60shown on the left side inFIG.2, and a second output flange68being provided on the bevel gear60shown on the right side inFIG.2.

A first axle shaft70is drivingly connected to the first output flange66and a second axle shaft72is drivingly connected to the second output flange68.

Each of the rear wheels14may be coupled to an end of the corresponding first axle shaft70or second axle shaft72which is remote from the differential gear unit26. More precisely the first or left rear wheel14is connected to the first axle shaft70and the second or right rear wheel14is connected to the second axle shaft72. Since the rear wheels14do not form part of the axle assembly16, they are represented in dotted lines inFIG.2.

Both the first axle shaft70and the second axle shaft72have the same length.

Moreover, the differential gear unit26is arranged centrally with respect to a vehicle width direction W.

The axle assembly16also comprises an inverter unit74.

Since in the present example, the first electric machine18and the second electric machine20are of the same type, the inverter unit74is a common or shared inverter unit74. This means that the inverter unit74is used for powering both the first electric machine18and the second electric machine20.

As can best be seen inFIG.3, the inverter unit74is partially arranged between the first electric machine18and the second electric machine20.

Moreover, the inverter unit is arranged on top of the spur gear unit22and the differential gear unit26.

The axle assembly16may be operated using a method for operating an axle assembly.

According to this method, only one out of the first electric machine18and the second electric machine20is operated in a first driving mode. The first driving mode may be a low load mode.

The first driving mode may be configured to be used in a standard driving situation. In the present example, only the first electric machine18may be used in such a situation, i.e., in the first driving mode.

Alternatively, a second driving mode may be used. In this second driving mode, both the first electric machine18and the second electric machine20may be operated. The second drivingly mode may be configured to be used in situations where high driving power is needed, for example if a strong acceleration is requested or if the vehicle10is driving up a steep hill. The second driving mode may be a high load mode.

In another example, the first electric machine18and the second electric machine20may be of different types. In this context, the first electric machine may be a permanent magnet synchronous machine. The second electric machine may be an induction machine or a synchronous reluctance machine.

Induction machines and synchronous reluctance machines have the advantage that they can be rotated passively without generating electromagnetic losses.

Also, the axle assembly16according to this example may be operated using the method for operating an axle assembly as has been described above.

Other variations to the disclosed examples can be understood and effected by those skilled in the art in practicing the claimed disclosure, from the study of the drawings, the disclosure, and the appended claims. In the claims the word “comprising” does not exclude other elements or steps and the indefinite article “a” or “an” does not exclude a plurality. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. Any reference signs in the claims should not be construed as limiting the scope of the claims.

LIST OF REFERENCE SIGNS

10vehicle12front wheel14rear wheel16axle assembly18first electric machine20second electric machine22spur gear unit24spur gear stage26differential gear unit28internal stator of the first electric machine30external rotor of the first electric machine32internal stator of the second electric machine34external rotor of the second electric machine36common shaft38housing40bearing unit42bearing unit44singular pinion46intermediate shaft48bearing unit50bearing unit52first gear54second gear56ring gear58cage60bevel gear62bearing unit64bearing unit66first output flange68second output flange70first axle shaft72second axle shaft74inverter unitW vehicle width direction