This application is a National Stage completion of PCT/EP2019/054781 filed Feb. 27, 2019, which claims priority from German patent application serial no. 10 2018 204 909.2 filed Mar. 29, 2018.

FIELD OF THE INVENTION

The present invention relates to an auxiliary power take-off assembly and a transmission with an auxiliary power take-off assembly.

BACKGROUND OF THE INVENTION

Vehicle transmissions in utility vehicles often comprise an auxiliary power take-off assembly by means of which various types of auxiliary aggregates in the vehicle can be driven. This applies in equal measure to transmissions with a friction disk clutch and a vehicle transmission equipped with a torque converter.

Auxiliary power take-off assemblies are used in particular in buses, trucks, construction machinery, agricultural vehicles or special vehicles.

Auxiliary power take-off assemblies are available in drive-dependent, clutch-dependent or motor-dependent versions. Drive-dependent auxiliary power take-off assemblies, for example, supply the hydraulic system of dual-circuit steering systems with a working pressure, whereby rolling vehicles can still be steered if the primary system has failed due to a motor breakdown. Clutch-dependent auxiliary power take-offs are suitable for short- or long-term operation during driving or at rest. Motor-dependent auxiliary power take-offs differ from clutch-dependent auxiliary power take-offs in that in motor-dependent auxiliary power take-offs there is a direct connection to the crankshaft of the drive motor, which bypasses the vehicle clutch or torque converter, so that such auxiliary power take-offs are mechanically permanently connected with the crankshaft of the drive motor. They are designed for high constant power in long-term operation and can be loaded with the maximum motor torque. They can be operated while the vehicle is driving or at rest, and can be engaged or disengaged under load. Motor-dependent auxiliary power take-offs are arranged between the motor and the transmission, they are driven always directly by the motor by way of a separate clutch, and can also be engaged and disengaged under load while the vehicle is driving or at rest.

From DE 10 2016 212 209 A1 an auxiliary power take-off assembly for a motor vehicle transmission with a torque converter is known, which has a driveshaft permanently connected to a drive motor of the motor vehicle by way of the pump shaft of the torque converter. Furthermore, the auxiliary power take-off assembly comprises a transmission chain with a drive input element, an intermediate wheel and a drive output element, whose drive output element is connected to an auxiliary aggregate that is to be driven, and a shifting element. The shifting element is arranged for the optional connection of the driveshaft to drive input element, and acts between the driveshaft and the drive input element of the transmission chain. In that way the auxiliary power take-off assembly can already be decoupled, behind the driveshaft connected to the pump shaft of the torque converter, completely from the rest of the transmission chain and the auxiliary aggregate, so that when not needed these elements do not have to co-rotate and do not therefore produce any losses and noise. The shifting element is permanently fitted in the transmission.

From the document DE 10 2015 121 019 A1 a transmission is known, which comprises a housing, an input shaft, a transmission shaft, a first and a second transmission element, a contiguous transmission element, a driveshaft and a torque-transmitting mechanism. The input shaft and the transmission shaft are in each case mounted rotatably in the housing and are parallel to one another. The first transmission element is connected to the input shaft so that they rotate together. The second transmission element is connected to the transmission shaft so that they rotate together. The contiguous transmission element engages with each of the first and second transmission elements. A second output shaft is arranged coaxially with the transmission shaft and is partially covered by the latter. The torque transmitting mechanism connects the transmission shaft selectively to the driveshaft. Thus, on the axis of the transmission shaft the invention comprises two separate shafts, the transmission shaft (driven shaft) and the second output shaft, wherein a separator clutch is arranged coaxially with the driven shaft and the second output shaft, and the driven shaft and the driven sprocket wheel are connected selectively thereby to the second output shaft. Thus, the driven shaft itself cannot be decoupled.

SUMMARY OF THE INVENTION

The purpose of the present invention is to improve and simplify the structure known from the prior art, and to minimize the installation effort. It should also be possible to retrofit the solution in an existing system.

This objective is achieved by an auxiliary power take-off assembly and a transmission with the characteristics specified in the independent claims. Design features are the subject of the subordinate claims.

An auxiliary power take-off assembly in a transmission of a motor vehicle is provided, the transmission having a torque converter, a transmission input and a transmission output, with a driveshaft permanently connected to a drive motor of the motor vehicle via the pump shaft of the torque converter at the transmission input, a transmission output shaft at the transmission output, and a transmission chain consisting at least of a drive input element and a drive output element, whose drive output element can be connected to an auxiliary aggregate to be driven, and with a shifting element, wherein the drive output element is arranged on a drive output shaft and by means of the shifting element, which is arranged and acts between the drive output shaft and the drive input element of the transmission chain, can be connected to the drive output shaft. In this case, the shifting element is integrated into the transmission housing in such manner that it can be retrofitted. Since the auxiliary power take-off assembly is accommodated inside the transmission housing under a housing cover, easier access to the components is possible. The housing cover forms part of the transmission housing. It is fixed detachably to the transmission housing and closes an opening in the transmission housing. The housing cover is preferably bolted to the transmission housing. The shifting element is located in the area of the drive output shaft and the drive output element, since it can connect those two components to one another and thus under the housing cover, whereby the installation and removal of the components is made possible or facilitated.

The transmission input is on the driven side of the transmission, where a drive unit passes torque into the transmission by way of an input shaft. The transmission output is on the drive output side, i.e. on that side of the transmission where a transmission output shaft transmits torque to a drive output shaft or a differential by means of which the wheels of the vehicle are driven. Thus, the transmission input is opposite the transmission output.

The driveshaft and the drive output shaft are preferably arranged with their axes parallel to one another. The intermediate shaft is arranged coaxially with the drive output shaft. The drive input element and the drive output element can be in the form of gearwheels, which engage directly in one another without an intermediate wheel. A further transmission element could also be interposed between the drive input element and the drive output element.

Auxiliary aggregates can be attached directly on the side of the transmission housing, or the drive output shaft can be extended by means of an intermediate shaft to the transmission output, so that auxiliary aggregates for connection can be arranged at the transmission output. The intermediate shaft can in that case be mounted in the drive output shaft. On the transmission output side, the intermediate shaft can have a driving profile which can receive a driveshaft or a drive output flange of an auxiliary aggregate. The driving profile can also be designed to receive a driveshaft or drive output flange of a hydraulic pump, or to receive a driveshaft of a step-up stage. The intermediate shaft is preferably at least partially surrounded by a protective tube.

The auxiliary power take-off assembly is part of a transmission.

