DE102016100819A1 - coupling device - Google Patents

Abstract

The coupling device for fastening an auxiliary machine to the rotor of an exhaust-gas turbocharger comprises a nut (31) with which the compressor wheel (20) of the exhaust-gas turbocharger is screwed tightly onto the shaft. Furthermore, the coupling device comprises a coupling element (52), which is positively connected to the shaft and positively connected to the nut. This results in the sum of a positive connection between the shaft (30) of the exhaust gas turbocharger and the coupling element (52).

Description

Technical area

The invention relates to the field of supercharged by exhaust gas turbochargers internal combustion engines. It relates to a coupling device for fastening an auxiliary machine to the rotor of an exhaust gas turbocharger.

State of the art

From an exhaust gas turbocharger with a high-speed rotor excess energy can be dissipated in different ways.

WO 2013/18308 A1 describes a system with an exhaust gas turbocharger, in which a hydraulic pump is connected via a coupling with the rotor of the exhaust gas turbocharger.

EP 1 961 936 A1 describes a so-called hybrid exhaust gas turbocharger, in which an electric machine is connected via a coupling with the rotor of the exhaust gas turbocharger and operated as a generator. If the electric machine is operated as a motor, energy can be supplied to the exhaust-gas turbocharger via the clutch.

The transmission of the torque from the rotor of the exhaust gas turbocharger to the clutch is advantageously carried out via a positive connection. EP 1 961 936 A1 shows a positive connection between the clutch and the compressor wheel.

If an existing exhaust gas turbocharger to be equipped with a system for energy recovery / energy supply, it is desirable to be able to realize the subsequently produced connection between the clutch and the rotor without changes to the rotor and in particular without changing the compressor.

Especially in rotors with attached by screws on the shaft compressor wheels, such as in DE 101 00 977 A1 reveals the problem that the screw is dissolved or excessively attracted when feeding or discharging the energy, whereby the quality of the connection between the compressor wheel and shaft could be impaired.

Brief description of the invention

The object of the present invention is to provide an easily retrofittable coupling device for fastening an auxiliary machine to the rotor of an exhaust gas turbocharger, which does not affect the screw connection between individual components of the rotor.

According to the invention, in the case of the rotor composed of several individual parts, the nut is fastened to the nut securing the compressor wheel to the shaft. The compressor wheel itself remains unaffected by the coupling device. The coupling device is attached to the nut and, according to the invention, has an additional means for torque transmission from the shaft to the coupling element. The torque transmitting means advantageously engages in a corresponding recess on the shaft end, which is needed for example when tightening the nut on the shaft to determine the shaft and is designed as a hexagon socket. The corresponding means for torque transmission is an external hexagon, which is formed directly on the coupling element or indirectly attached via an intermediate piece on the coupling element and thus ensures a positive connection between the shaft and the coupling element.

If the screwed attachment of the compressor wheel to the shaft comprises a multi-part shaft with a shaft insert screwed into the shaft, the threaded connection between an internal thread on the shaft and an external thread on the shaft insert is secured against unintentional loosening of this threaded connection by an anti-rotation element. The anti-rotation element is pushed as an annular element on the shaft insert and screwed with an external thread up to a stop in an additional internal thread in the shaft. Optionally, the two threaded connections on different thread pitches to further complicate the unwanted loosening.

Brief description of the drawings

Hereinafter, various embodiments of the invention will be explained in detail with reference to drawings. This shows

1 a schematic representation of a system with an internal combustion engine, an exhaust gas turbocharger and a connected to the exhaust gas turbocharger auxiliary machine,

2 a first embodiment of a coupling device for fixing the auxiliary machine on the rotor of the exhaust gas turbocharger in the unsecured state,

3 the coupling device according to 2 in the attached state,

4 a second embodiment of a coupling device for fixing the auxiliary machine on the rotor of the exhaust gas turbocharger in the unsecured state,

5 the coupling device according to 4 in the attached state,

6 A third embodiment of a coupling device for fastening the auxiliary machine to the rotor of the exhaust gas turbocharger,

7 an enlarged view of the section VII of the coupling device according to 6 with an anti-rotation element,

8th the anti-rotation element of the coupling device according to 7 , and

9 a view on the guided along IX-IX section through the coupling device according to 2 ,

Way to carry out the invention

1 schematically shows a charging device of an internal combustion engine 10 comprising an exhaust gas turbocharger with an exhaust gas turbine 4 and a compressor 2 , where turbine wheel and compressor wheel via a shaft 30 the exhaust gas turbocharger are interconnected. Compressor side is via a coupling 50 an auxiliary machine connected to the rotor of the exhaust gas turbocharger. The auxiliary machine is, for example, an electric machine or a hydraulic pump for feeding or removing energy from the exhaust gas turbocharger.

2 shows an arrangement with one on the shaft 30 deferred compressor wheel 20 , which with a screwed onto an external thread of a shaft end nut 31 secured against an axial stop. The shaft has at its free end a recess in which typically a hexagon socket is formed. The hexagon socket is used to hold a mounting tool when tightening the nut on the shaft. The assembly tool keeps the shaft steady while the nut can be tightened. According to the invention, a coupling element 52 , which is shown cut off to the left side, with the mother 31 brought into a positive connection, as in 3 shown. This is done by tightening the several, distributed along the circumference fastening screws 53 in designated holes in the nut 31 , Central has the coupling element 52 an axially directed projection 54 on which the hexagon socket is designed accordingly as a hexagon, and the assembly of coupling element 52 and mother 31 enters into a positive connection with the depression in the shaft end. In sum, these two form-fitting leads to a releasable, positive connection between the shaft and the coupling element, which serves for optimal torque transmission from the shaft to the coupling element. Thanks to the positive connection between the axial projection on the coupling element and the recess in the shaft end, which is responsible for the clamping of the compressor between the nut and axial stop on the shaft shoulder threaded connection between mother remains 31 and wave 30 from the torque transfer to the coupling element unimpaired.

Optionally, in this embodiment or in all embodiments presented below, instead of a hexagon socket in the recess in the shaft end and a hexagon socket on the projection on the coupling element, a differently shaped, mutually matched contour can be provided. Projection and depression can also be reversed. Or the recess and the projection may be cone-shaped, in which case the torque transmission is not done by a positive connection between the recess and projection, but by a pressed adhesion. This also allows any angular deviations when assembling the fasteners 53 with the provided for their inclusion holes in the mother compensate. In the case of the positive connection by means of matching contour, the fastening means 53 as in 9 shown in elongated holes extending along the circumference 51 arranged and can be moved within these slots in the desired position. Optionally, washers may be provided between the screw heads of the fastening means and the elongated holes having the flange of the coupling element to cover the slots and to ensure a large-area pressure.

4 shows a second embodiment of the coupling device, wherein the coupling element 52 is connected to the rotor of the exhaust gas turbocharger on a larger radius. This is done on the mother 31 , which holds the compressor wheel, a first intermediate piece 55 fastened, for example, by several, distributed along the circumference arranged fastening screws, as shown in the upper part of the picture. Subsequently, over another intermediate piece 56 the positive connection between the shaft 30 and the first intermediate piece 55 manufactured by being introduced as in the first embodiment of the axial projection as an external hexagon in the central recess in the shaft end and the second intermediate piece is fastened by means of a plurality of distributed along the circumference arranged fastening screws on the first intermediate piece. Last is the coupling member 52 with a plurality of outwardly disposed, in turn distributed along the circumference arranged fastening screws on the intermediate piece 55 attached, as in 5 shown. This results in the sum of the now three positive locking a releasable, positive connection between the shaft and the coupling element.

Is the wave as in 6 implied composed of two nested parts, an anti-rotation element is used to secure this threaded connection according to the invention. To 7 sits the anti-rotation element 38 on the shaft insert 35 , which with one end in a central opening of the shaft 30 used and over the threaded connection 36 is screwed. This is when inserting the Welleneinsatzstücks 35 screwed into the shaft, the shaft insert piece to the stop at the bottom of the recess and thereby clamped. An over-rotation in the screwing direction is thereby prevented in later operation. Thus, this threaded connection must be secured only in the other direction of rotation, that it does not come to an unwanted loosening of the threaded connection when a corresponding moment abruptly or permanently. The anti-rotation element 38 is pushed when mounting the shaft insert from its free end on the shaft insert and last until it stops at the projection 351 screwed with an external thread on Verdrehsicherungselement in an internal thread at the free end of the shaft.

This in 8th individually shown anti-rotation element may have a separate, inwardly directed projection 382 have, or simply be ring-shaped and rest with one end face on the projection on Welleneinsatzstück. For the anti-rotation is crucial that the projection rests against the shaft insert during operation on the anti-rotation and thus a displacement of the shaft insert is excluded in the axial direction. The threaded connection between shaft insert and shaft is thus clamped in both directions of rotation. A loosening of this threaded connection is only possible again when the anti-rotation element is unscrewed from its threaded connection and moved in the axial direction over the shaft insert to its free end. Optionally, the threads of the two threaded connections can have different thread pitches.

LIST OF REFERENCE NUMBERS

10

 internal combustion engine

2

 Compressor of the exhaust gas turbocharger

20

 compressor

30

 Shaft of the exhaust gas turbocharger

31

Nut for fastening the compressor wheel ( 20 ) on the shaft ( 30 )

32

 Means for transmitting torque to the shaft (hexagon socket)

35

 Shaft insert

351

 Projection on the shaft insert

36

Threaded connection between shaft insert ( 35 ) and wave ( 30 )

37

Thread connection between anti-rotation element ( 38 ) and wave ( 30 )

38

 anti-rotation

381

External thread on anti-rotation element ( 38 )

382

Projection on the anti-rotation element ( 38 )

4

 Turbine of the exhaust gas turbocharger

50

 Coupling device for attaching an auxiliary machine to the rotor of the exhaust gas turbocharger

51

 Long hole

52

 coupling member

53

 fixing screw

54

 Means for torque transmission at the coupling device (axial projection)

55

 connecting piece

56

 Intermediate piece for torque transmission

60

 Auxiliary machine (electric machine, hydraulic pump, etc.)

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• WO 2013/18308 A1 [0003]
• EP 1961936 A1 [0004, 0005]
• DE 10100977 A1 [0007]

Claims (10)

Coupling device for fastening an auxiliary machine to the rotor of an exhaust gas turbocharger, comprising a nut ( 31 ) for screwing onto a shaft ( 30 . 35 ) of an exhaust gas turbocharger, and a coupling element ( 52 ) for fastening to the nut, characterized in that the coupling device is a means ( 54 ) for torque transmission, which can cooperate for transmitting a torque from a shaft of an exhaust gas turbocharger to the coupling device with a corresponding means for torque transmission to a shaft of an exhaust gas turbocharger. Coupling device according to claim 1, wherein the means ( 54 ) has a contour for torque transmission of the coupling device, which is suitable to enter into a positive connection with a corresponding mating contour on a shaft of an exhaust gas turbocharger. Coupling device according to claim 2, wherein the means for torque transmission of the coupling device comprises a projection having a contour which is adapted to form a positive connection with a corresponding counter contour in a sinking on a shaft of an exhaust gas turbocharger. Coupling device according to claim 2, wherein the means for torque transmission of the coupling element has a Axialversenkung with a contour which is suitable to enter with a corresponding mating contour on a projection on a shaft of an exhaust gas turbocharger a positive connection. Coupling device according to one of claims 1 to 4, wherein the coupling element ( 52 ) via a first intermediate piece ( 55 ) at the mother ( 31 ), wherein the first intermediate piece is fastened to the nut, and the coupling element is fastened to the first intermediate piece. Coupling device according to one of claims 1 to 5, wherein the means ( 54 ) for torque transmission of the coupling device to a second intermediate piece ( 56 ), which is attached to the nut, or to the first intermediate piece or to the coupling element. Coupling device according to one of claims 1 to 6, further comprising a shaft insert ( 35 ), which at a first end has an external thread for screwing into an internal thread in a recess on a shaft of an exhaust-gas turbocharger and which at the second end has an external thread for receiving the nut ( 31 ), wherein the coupling device an anti-rotation element ( 38 ), which is annular and from the second end of Welleneinsatzstücks to a projection ( 351 ) is guided on the shaft insert over the shaft insert, wherein the anti-rotation element ( 38 ) an external thread ( 381 ), wherein the anti-rotation element can be screwed with the external thread in a corresponding internal thread of a recess on a shaft of an exhaust gas turbocharger. Coupling device according to claim 7, further comprising the shaft of an exhaust gas turbocharger, wherein in the shaft of the exhaust gas turbocharger a recess with two internal threads is embedded, wherein a first internal thread for a threaded connection ( 36 ) with an external thread in the region of the first end of the shaft insert ( 35 ) is provided, and a second, relative to the first internal thread radially outwardly and axially offset to the shaft end female thread for a threaded connection ( 37 ) with the external thread ( 381 ) on the anti-rotation element ( 38 ) is provided, wherein the anti-rotation element until it stops at the projection ( 351 ) is screwed into the second internal thread on the shaft insert. Coupling device according to claim 8, wherein the threaded connections have different thread pitches. Charging device, comprising an exhaust gas turbocharger and an auxiliary machine, which is connected by means of a coupling device according to one of claims 1 to 9 with the rotor of the exhaust gas turbocharger.

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