Belt drive arrangement for a drive train of a helicopter

The invention relates to a belt drive assembly for a drive train of a helicopter, comprising a drive shaft that can be functionally connected to a crankshaft of a drive machine of the helicopter, wherein the drive shaft is functionally connected to a belt disk via a torsional vibration damper, wherein the belt disk can rotate via a bearing mechanism on a bearing shaft connected to the drive shaft for conjoint rotation therewith, wherein the belt disk can receive a belt that is functionally connected to a rotor system of the helicopter.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority from German Patent Application DE 10 2018 214 789.2, filed Aug. 30, 2018, the entirety of which is hereby fully incorporated by reference herein.

The invention relates to a belt drive arrangement for a drive train of a helicopter.

By way of example, DE 10 2010 062 325 A1 discloses a disk-shaped component for a belt drive, in particular for the drive of one or more ancillary units of an internal combustion engine, which can be attached to an output shaft of the internal combustion engine, in particular the crankshaft. The disk-shaped component has a torsional vibration damper, located between an input component dedicated to the output shaft and an output component that can rotate in relation thereto. The input and output components can rotate in relation to one another via a bearing. The bearing is composed of a radially outward bearing flange and a radially inward bearing pin. The bearing flange can be connected to the output shaft of the internal combustion engine.

The problem addressed by the present invention is to create a belt drive arrangement for a drive train of a helicopter. This problem is solved by the subject matter of claim1. Preferred embodiments are the subject matter of the dependent claims.

A belt drive arrangement according to the invention for a drive train of a helicopter comprises a drive shaft that can be functionally connected to a crankshaft of a drive machine of the helicopter, wherein the drive shaft is functionally connected to a belt disk via a torsional vibration damper, wherein the belt disk can rotate on a bearing shaft that is connected to the drive shaft for conjoint rotation via a bearing assembly, and wherein a belt functionally connected to a rotor system of the helicopter can be received on the belt disk.

In other words, the belt drive arrangement is integrated in the drive train of the helicopter such that a drive torque generated by the drive machine, which is preferably in the form of a piston engine, is dampened via the torsional vibration damper, and at least introduced into the rotor system of the helicopter. In particular, the torsional vibration damper is axially adjacent to the belt disk. The belt disk surrounds the bearing shaft radially, and is rotatably supported thereon.

The term “functionally connected” is understood to mean that two components can be connected directly to one another, or other components can be located in the power train between the two components. Furthermore, two components that are functionally connected to one another can be connected directly to one another, or indirectly, via further components located between them.

The torsional vibration damper preferably comprises a spring mechanism, wherein the spring mechanism couples at least one input element to at least one output element in a manner that dampens vibrations. The at least one input element introduces the drive torque of the drive machine into the torsional vibration damper, wherein the drive torque is transferred to the at least one output element, dampened by the spring mechanism, such that it can then be transferred to the belt disk via the at least one output element. At the same time, the torsional vibration damper allows the drive shaft to be connected to the belt disk via the spring mechanism incorporated therein, such that torque can be transferred in a non-rigid manner.

The at least one input element is preferably located axially between the drive shaft and the bearing shaft, and is connected to the drive shaft and the bearing shaft for conjoint rotation therewith. In other words, either one input element or numerous input elements are located axially between the drive shaft and the bearing shaft. The at least one input element extends radially into the torsional vibration damper and is functionally connected to the spring mechanism therein.

It is also preferred that at least one input element is in the form of an annular disk, and has numerous holes for axially inserting connecting means between the drive shaft and the bearing shaft. In particular, the holes are evenly distributed over the circumference of the annular disk. Preferably, both screw elements as well as shear pins are used as the connecting means. In particular, the screw elements and shear pins are placed in the holes in an alternating sequence over the circumference.

In accordance with one measure that further improves the invention, the at least one output element is located on the front surface of the belt disk, and connected to the belt disk for conjoint rotation. In particular, the at least one output element is connected to the belt disk via numerous screw elements. The at least one output element preferably bears at least in part on a front surface section of the belt disk provided for this.

According to a preferred embodiment, a first and second output element form a housing of the torsional vibration damper, wherein the first output element is in the form of a housing well, and the second output element is in the form of a housing cover. The spring mechanism is also located inside the housing, such that the housing protects the spring mechanism from contaminants and moisture. In particular, respective housing components, specifically the housing well and the housing cover, are supported on respective rings. One of the two rings bears on the bearing shaft and the input element, and the other ring bears on the drive shaft and the input element. The input element is tensioned axially between the two rings.

An ancillary drive shaft is preferably connected to the belt disk for conjoint rotation therewith, wherein the ancillary drive shaft is functionally connected to an ancillary unit of the helicopter. The ancillary unit, or auxiliary unit, is preferably a fan. The drive for the ancillary unit is thus dampened, along with the drive for the rotor system, by the torsional vibration damper, such that torque peaks and operational irregularities, in particular, can be absorbed. Furthermore, wear to the drive components in the drive train can be reduced by the torsional vibration damper.

The invention includes the technical teaching that the bearing mechanism comprises a first and a second tapered roller bearing. The two tapered roller bearings for an O-assembly. In particular, a tensioning sleeve is located between the two tapered roller bearings. A respective outer ring of the respective tapered roller bearing is located on an inner circumferential flange of the belt disk, wherein a respective inner ring of the respective tapered roller bearing is located on an outer circumferential flange of the bearing shaft. The belt disk and the bearing shaft can rotate, at least partially, in relation to one another.

In particular, it is proposed that the belt drive arrangement according to the invention be used in a drive train of a helicopter.

The invention also relates to a helicopter that has a belt drive arrangement according to the invention, wherein the belt drive arrangement is integrated in the drive train of the helicopter, and dampens vibrations. In particular, a drive machine in the form of a piston engine that is functionally connected to the belt drive arrangement is also located in the drive train of the helicopter.

According toFIG. 1andFIG. 2, a respective belt drive arrangement13according to the invention for a drive train of a helicopter14has a drive shaft1, which is functionally connected to a crankshaft2of a drive machine15of the helicopter14. Furthermore—and not shown herein—the drive shaft1and the crankshaft2can be functionally connected to a starter gear of a drive device. The starter gear can be incorporated in the intersection between the drive shaft1and the crankshaft2. The drive shaft1is functionally connected to a belt disk4via a torsional vibration damper3. The torsional vibration damper3comprises a spring mechanism8. The belt disk4can rotate via a bearing mechanism5on a bearing shaft6connected to the drive shaft1for conjoint rotation. The bearing mechanism5comprises a first and second tapered roller bearing5a,5b, wherein the two tapered roller bearings5a,5bform an O-assembly. Furthermore, the bearing mechanism5is sealed via first and second seals19a,19b, dedicated to the respective tapered roller bearings5a,5b, and secured axially by a bearing cover20. A tensioning sleeve21is located between the two tapered roller bearings5a,5b.

The bearing shaft6and the drive shaft1are hollow shafts located on a common drive axis16, together with the crankshaft2. The belt disk4is coaxial to the bearing shaft6. The belt disk4also receives a belt that is functionally connected to a rotor system18of the helicopter14. In the present case, the belt is not shown, although the belt track17on the belt disk4is shown, which corresponds to the belt. The belt track17has numerous V-shaped notches, which can receive at least one, preferably numerous, belts.

Furthermore, the ancillary drive shaft12is connected to the belt disk4for conjoint rotation. The ancillary drive shaft12is intended to be functionally connected to an ancillary unit of the helicopter14. By way of example, the ancillary unit can be a fan. The ancillary drive shaft12can rotate via a bearing element22. The torque generated by the drive machine15is introduced via the torsional vibration damper3into both the belt disk4and the ancillary drive shaft12.

According toFIG. 1, the spring mechanism8of the torsional vibration damper3couples two input elements7a,7bto an output element9such that vibrations are dampened. The first input element7abears on the drive shaft1and is functionally connected to the spring mechanism8. The second input element7bbears on the bearing shaft6, and is functionally connected to the spring mechanism8. The respective input elements7a,7bform annular disks, and have numerous holes10for axially inserting connecting means11between the drive shaft1and the bearing shaft6. In the present case, there are two connecting means11in the form of shear pins in the intersection surface. The connecting means11extend, at least in part, axially through the drive shaft1and the bearing shaft6, as well as entirely through the respective holes10on the respective input elements7a,7b. The output element9is located on the front surface of the belt disk4, and is connected to the belt disk4for conjoint rotation via screws. In the present case, the output element is in the form of an annular disk.

According toFIG. 2, the spring mechanism8of the torsional vibration damper3couples an input element7to two output elements9a,9bsuch that vibrations are dampened. The input element7bears axially between the drive shaft1and the bearing shaft6, and is functionally connected to the spring mechanism8. The input element7is in the form of an annular disk, and has numerous holes for axially inserting connecting means11between the drive shaft1and the bearing shaft6. In the present case, there are two connecting means11in the form of screw elements in the interaction surface. The connecting means11extend, at least in part, axially through the drive shaft1and the bearing shaft6, and entirely through the respective holes10on the input element7. The first and second output elements9a,9bform a housing for the torsional vibration damper3, wherein the first output element9aforms a housing well, and the second output element9bforms a housing cover. The first output element9ais located on the front surface of the belt disk4, wherein the second output element9bbears at least in part on the front surface of the first output element9a, and wherein both output elements9a,9bare connected to the belt disk4for conjoint rotation via screws.

A helicopter14with a belt drive arrangement13according to the invention is shown inFIG. 3. The belt drive arrangement13is functionally located in a drive train of the helicopter14, wherein the drive train comprises a drive machine15at the input end, and a rotor system18at the output end, which has first and second rotors18a,18b.

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