DE102010048099A1 - Impeller for an exhaust gas turbocharger, exhaust gas turbocharger and method for balancing a running gear for an exhaust gas turbocharger - Google Patents

Abstract

The invention relates to an impeller (14) for an exhaust gas turbocharger, which can be rotatably supported in a housing of the exhaust gas turbocharger about an axis of rotation (18) and which has a wheel back (20) with at least one balancing mark (22, 24) Balancing mark (22, 24) in the circumferential direction (26) of the wheel back (20) extends at least substantially in an arcuate manner and via an at least substantially transitional region (32) extending in the direction of extension (26) of the balancing mark (22, 24) into the adjoining wheel back (20) merges, a tangent (34) extending through an intersection (S) of the transition region (32) with the wheel back (20) adjoining this to the transition region (32) enclosing an angle γ with the wheel back (20), which is at least substantially less than 15 degrees, and an exhaust gas turbocharger with such an impeller (14). The invention also includes a method for balancing a rotor (10) for an exhaust gas turbocharger.

Description

The invention relates to an impeller for an exhaust gas turbocharger of the type specified in the preamble of claim 1, an exhaust gas turbocharger according to claim 9 and a method for balancing a running gear for an exhaust gas turbocharger specified in the preamble of claim 10. Art.

The US 3,446,100 discloses a device for automatically correcting an imbalance of an object. In this case, a so-called balancing mark is introduced into the object.

In addition, it is known to balance wheels for exhaust gas turbochargers by providing at least one impeller of the power tool with a balancing mark. In this case, this balancing mark is introduced, for example, in a Radrücken the impeller.

It is an object of the present invention to provide an impeller for an exhaust gas turbocharger, such an exhaust gas turbocharger and a method for balancing a rotor of such exhaust gas turbocharger, whereby an improved balancing is possible.

This object is achieved by an impeller for an exhaust gas turbocharger having the features of patent claim 1, by an exhaust gas turbocharger having the features of patent claim 9, and by a method for balancing a power tool for an exhaust gas turbocharger having the features of patent claim 10. Advantageous embodiments with expedient and non-trivial developments of the invention are specified in the dependent claims.

The first aspect of the invention relates to an impeller for an exhaust gas turbocharger, which is rotatably mounted in a housing of the exhaust gas turbocharger about an axis of rotation, and which has a Radrücken with at least one balancing mark.

According to the invention, it is provided that the balancing mark extends in the circumferential direction of the wheel back at least substantially arcuate and transitions over a substantially extending in the extension direction of the balancing transition region in the adjoining Radrücken, with a running through an intersection of the transition region with the adjoining Radrücken tangent at the transition region includes an angle with the Radrücken, which is at least substantially less than 15 °. This design of the balancing mark is a running gear, which is associated with the impeller and which comprises a shaft with which the impeller rotatably connect, or is connected, particularly well to balance, so that the running gear a particularly good and at least almost unbalance-free rotational movement during the operation of the exhaust gas turbocharger can perform.

In addition, sharp edges are avoided on the Radrücken of the impeller by the formation of the balancing brand, whereby a high strength, especially against centrifugal forces during operation of the exhaust gas turbocharger, is reached.

In a particularly advantageous embodiment of the invention, the balancing mark extends in the circumferential direction of the wheel back at least substantially circular segment-shaped. By this at least substantially arcuate course of the balancing mark the running gear is particularly well balanced. Furthermore, in addition sharp and the strength of the impeller negatively influencing edges, transitions or the like are avoided.

In a further advantageous embodiment, the Radrücken on at least two balancing marks, both of which are advantageously formed circular segment-shaped and extend in the circumferential direction of the Radrücken at least substantially over an angular range equal to or less than 180 °. This allows a further improved balancing of the running tool and the representation of a particularly smooth soft curve of the balancing mark without sharp edges or transitions or the like, which is the strength of the impeller especially against centrifugal beneficial.

The provision of two balancing marks, for example, allows a two-stage balancing, wherein in a first step of balancing one of the balancing marks and in a second step, the second balancing mark is formed. This is provided, for example, if a measurement carried out after the first step of balancing shows that there is still an undesirably high unbalance of the power tool. Thus, in a second step, a particularly finely tuned balancing can take place and the balancing of the power tool can be reduced to a minimum.

To illustrate a particularly good balancing of the running tool, it is advantageous if the balancing marks are formed at least essentially mirror-symmetrically to a straight line extending in the radial direction of the running wheel through the axis of rotation. This avoids the emergence of new imbalances by the provision of the balancing marks, so that the running gear has a particularly good and quiet rotational movement during operation of the exhaust gas turbocharger.

In a particularly advantageous embodiment of the invention, the balancing mark comprises a radial balancing mark profile and a radial and outer balancing edge edge, wherein a first passing through a first intersection of the outer balancing edge edge with the balancing brand profile tangent to the balancing mark profile and / or a second by a second intersection the inner Wuchtmarkenkante with the Wuchtmarkenprofil extending tangent to the balancing brand profile include an angle with the Radrücken, which is at least substantially less than 40 °. In other words, the value of the tangent angle of the first tangent and / or the second tangent with the Radrücken is less than 40 °. The advantage of limiting the value of at least one of these angles is that sharp edges and transitions on the Radrücken are avoided in the region of the radially outer and radially inner Wuchtmarkenkante. This results in a further increased strength of the impeller, in particular with respect to centrifugal forces, which arise during operation of the exhaust gas turbocharger.

In a further embodiment, the radial balancing mark profile is formed arcuate, whereby a further increase in the strength is brought about. The radial balancing mark profile can be, for example, circular, elliptical, parabolic or oval-shaped, in particular deviating from a circular shape. Important is an arcuate configuration of the radial balancing mark profile, as this notch stress relevant edges and the associated increased voltages can be avoided. If the radial balancing profile has a relative balancing mark radius whose value is at least 0.08 times the outer radius of the impeller, this has the advantage that a further increase in strength is achieved as a result.

It is also advantageous if a balancing mark depth of the radial balancing mark profile has at most 0.025 times the value of the outer wheel radius, as a result of which the strength of the running wheel is additionally increased.

In a further advantageous embodiment of the invention, the inner balancing mark edge has an inner balancing mark radius whose value is at least 0.51 times the value of the outer wheel radius, with the advantage that a further increase in the strength of the impeller is realized. In a further advantageous embodiment, the outer balancing mark edge has an outer balancing mark radius whose value is at most 0.85 times the value of the outer wheel radius. This contributes to a further increase in the strength of the impeller.

Moreover, it is advantageous if the balancing mark depth is designed to extend axially parallel to the axis of rotation in the direction of at least one impeller blade of the impeller. To ensure a particularly low-friction, in particular friction-free, rotation of the impeller with respect to a housing section of a housing of the exhaust gas turbocharger in which the impeller is received or received, a necessary minimum gap between the Radrücken and the corresponding housing section, air duct section or exhaust duct section is necessary. If the balancing mark depth is designed to extend in the direction of the impeller blade, balancing of the corresponding impeller or running tool can take place inexpensively without changing the minimum gap.

In a further advantageous embodiment of the invention, the balancing mark depth is formed axially extending parallel to the axis of rotation in the direction of a shaft, with which the impeller is rotatably connected, extending. This has the advantage, in particular with filigree wheels in lightweight design, that a balance can be brought about, without removing further material.

The second aspect of the invention relates to an exhaust gas turbocharger for an internal combustion engine, with a rotatably mounted in a housing running gear, which comprises a shaft and at least one rotatably connected to the shaft according to the invention impeller. Advantageous embodiments of the first aspect of the invention are to be regarded as advantageous embodiments of the second aspect of the invention and vice versa. As a result of the advantageous balancing of the impeller and in particular of the power tool, the running gear of the turbocharger has a particularly smooth rotational movement, which is beneficial for efficient operation of the exhaust gas turbocharger and a long service life.

The third aspect of the invention relates to a method for balancing a in a housing of an exhaust gas turbocharger rotatably mounted about a rotation axis to Laufzeugs, in particular an impeller, wherein at least one balancing mark is formed on a Radrücken an impeller of the running tool. According to the invention, it is provided that the balancing mark is formed extending in the circumferential direction of the wheel back at least substantially arcuate, wherein as a result of forming the balancing mark this merges over a substantially extending in the direction of extension of the balancing transition area in the adjoining Radrücken, and wherein a through an intersection of the transitional region with the tangent to said transitional region extending at said adjoining Radrücken encloses an angle with the Radrücken, which is at least substantially less than 15 °. Advantageous embodiments of the first two aspects of the invention are to be regarded as advantageous embodiments of the third aspect of the invention and vice versa. As a result of the formation of the balancing mark, the method according to the invention makes possible particularly good balancing of the impeller and, in particular, of the power tool, sharp edges and transitions on or in the wheel back being avoided as a result of the limitation of the angle. This is the strength of the impeller, especially against centrifugal forces that occur during operation of the exhaust gas turbocharger beneficial. This allows a particularly long life of the running gear and thus the turbocharger. The life of the exhaust gas turbocharger is also the particularly quiet rotational movement of the impeller or the running gear beneficial, which is realized by the corresponding formation of the balancing mark.

The balancing mark is preferably introduced by means of a milling cutter in the Radrücken, which not only moves substantially parallel to the axis of rotation of the impeller, but is also moved in the circumferential direction of the Radrücken to form the balancing mark at least substantially circular and thus arcuate.

In this case, the cutter is moved, for example, in the circumferential direction of the Radrücken in an angular range of from greater than or equal to 1 ° to smaller equal to 180 °, whereby the at least substantially circular balancing mark is formed. In the context of the method according to the invention, it is possible to balance the impeller or the running gear of the exhaust gas turbocharger fully automatically by means of a balancing machine.

The running tool is provided, for example by a user of the balancing machine with a 0 ° reference mark. The running tool is removed from a loading system to a receiving position of a feed belt to the balancing machine and placed in a measuring station without angular position orientation. This is followed by an automatic measurement run. Then the running gear, which represents a balancing body to be balanced, braked to a standstill and determined during the measurement unbalance values, that is size and angle, displayed on a meter and output and transmitted via an interface for further processing.

The loading system is then another rotor, which is also referred to as rotor, at the receiving position. The first runner is picked up from the measuring station of the loading system. The first loading system loads the measuring station with the other tool. The further loading system stores the first rotor in a balancing station, after which the balancing starts fully automatically, so that determined imbalances are at least substantially eliminated.

As part of the unbalance compensation, the running gear is tensioned and screwed into a balancing position of a first level. This is followed by a compensation of the imbalance or imbalances in the first level by grinding. Then a further compensation by grinding in a second plane, whereupon the running gear is relaxed. The further loading system stores the tool for a control run in the measuring station, and an automatic control run is performed. Subsequently, the running gear is removed from the measuring station by means of the first loading system and placed on a belt. If the imbalance or unbalance after this first balancing is not within a tolerance, then a further balancing can be carried out.

If the imbalance in the first measuring run is greater, so that it can not be compensated for at least substantially by the balancing, an overcompensation is carried out during the first equalization. This ensures a still free welding surface by a second balancing. A possibly to be performed balancing can be carried out for example by means of a manual grinding compensation at a separate control station.

This fully automatic procedure allows the time and cost balancing of the tool with a low cycle time.

Further advantages, features and details of the invention will become apparent from the following description of a preferred embodiment and from the drawing. The features and feature combinations mentioned above in the description as well as the features and feature combinations mentioned below in the description of the figures and / or in the figures alone can be used not only in the respective combinations indicated, but also in other combinations or alone, without the scope of To leave invention.

The drawing shows in:

1 a schematic perspective view of a rotor of an exhaust gas turbocharger with a shaft and a rotatably connected to the shaft turbine wheel, which has a Radrücken with two balancing notches;

2 a schematic plan view of the rotor according to 1 ; and

3 in sections, a schematic sectional view along the section line AA in 2 ,

The 1 shows a toy 10 for an exhaust gas turbocharger, which is a shaft 12 as well as one with the wave 12 rotatably connected turbine wheel 14 includes. The turbine wheel 14 has a plurality of impeller blades connected to a wheel hub 16 on which of exhaust gas of an internal combustion engine can be flowed. As a result of the flow is the turbine wheel 14 and with it the wave 12 in a rotational movement about a rotation axis 18 offset, with the axis of rotation 18 the wave 12 as well as the turbine wheel 14 and thus the entire running gear 10 assigned.

To represent a particularly smooth rotary movement of the tool 10 are at a Radrücken 20 of the turbine wheel 14 two balance scores 22 and 24 provided, which in the circumferential direction in the direction of the Radrücken according to a directional arrow 26 at least substantially circular segment-shaped. The force scores 22 and 24 are mirror-symmetrical to each other as a correction variable.

How the particular 2 can be seen, extend the balancing notches 22 and 24 in the circumferential direction of the Radrücken 20 each over a circumferential angle δ, which is substantially greater than 30 °, in particular greater than 90 ° and in particular greater than 120 °, but at least substantially smaller than 180 °. In the 2 this is based on the force notch 22 shown. But this also applies analogously to the force notch 24 ,

Of the 2 it can also be seen that the balancing notches 22 and 24 relative to a radial direction of the turbine wheel 14 according to a directional arrow 28 through the axis of rotation 18 running straight line 30 are formed mirror-symmetrically. This is the way of the wheel 10 a particularly quiet rotational movement.

The 3 shows a section AA along in the 2 illustrated section line AA. especially the 3 shows that the force notch 22 (analogous applies to the force notch 24 ) over at least substantially in the extension direction of the balancing mark 22 according to the directional arrow 26 extending transition area 32 the force notch 22 in the adjoining Radrücken 20 passes. One closes by an intersection S of the transition region 32 with the at this subsequent Radrücken 20 running tangent 34 to the transition area 32 an angle γ with the Radrücken 20 which is at least substantially less than 15 °. The transition area 32 in this case provides an outlet of a grinding wheel or a milling head for forming the balance notch 22 in the Radrücken 20 is, are avoided by the limitations of the angle γ at least substantially below 15 ° undesirably sharp edges and transitions of the Radrückens. This leads to a strength of the turbine wheel 14 , in particular to centrifugal forces that occur during operation of the exhaust gas turbocharger.

The in the 1 to 3 illustrated training of balancing notches 22 and 24 on the one hand allow a particularly good balancing of the tool 10 so that this has a particularly quiet rotational movement. On the other hand, the turbine wheel 14 a particularly high strength, resulting in a long service life of the tool 10 and thus the entire exhaust gas turbocharger leads. The angle γ thus represents the outlet angle of the grinding wheel or the milling head.

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

• US 3446100 [0002]

Claims (10)

Wheel ( 14 ) for an exhaust gas turbocharger, which in a housing of the exhaust gas turbocharger about an axis of rotation ( 18 ) is rotatably support, and which a Radrücken ( 20 ) with at least one balancing mark ( 22 . 24 ), characterized in that the balancing mark ( 22 . 24 ) in the circumferential direction ( 26 ) of the Radrücken ( 20 ) extends at least substantially arcuately and over at least substantially in the extension direction ( 26 ) of the balancing mark ( 22 . 24 ) transition area ( 32 ) in the adjoining Radrücken ( 20 ), one passing through an intersection (S) of the transition region ( 32 ) with which at this subsequent Radrücken ( 20 ) running tangent ( 34 ) to the transition area ( 32 ) an angle (γ) with the Radrücken ( 20 ), which is at least substantially less than 15 degrees. Wheel ( 14 ) according to claim 1, characterized in that the balancing mark ( 22 . 24 ) in the circumferential direction ( 26 ) of the Radrücken ( 14 ) extends at least substantially circular segment. Wheel ( 14 ) according to one of the preceding claims, characterized in that the balancing mark ( 22 . 24 ) in the circumferential direction ( 26 ) of the Radrücken ( 20 ) extends over an angular range (δ) which is at least substantially equal to or less than 180 degrees. Wheel ( 14 ) according to one of the preceding claims, characterized in that the Radrücken ( 20 ) at least two balancing marks ( 22 . 24 ) having. Wheel ( 10 ) according to claim 4, characterized in that the balancing marks ( 22 . 24 ) to a radial direction ( 28 ) through the axis of rotation ( 18 ) of the impeller ( 14 ) straight line ( 30 ) are mirror-symmetrical. Wheel ( 14 ) according to one of the preceding claims, characterized in that the balancing mark ( 22 . 24 ) comprises a radial balancing mark profile and a radial and outer balancing edge edge, wherein a first, extending through a first intersection of the outer balancing edge edge with the balancing brand profile tangent to the balancing brand profile and / or a second, by a second intersection of the inner balancing mark edge with the balancing brand profile extending tangent to the balancing mark profile include an angle with the Radrücken, which is at least substantially less than 40 degrees. Wheel ( 14 ) according to claim 6, characterized in that the radial balancing mark profile is at least partially arcuate. Wheel ( 14 ) according to one of claims 6 or 7, characterized in that the radial balancing mark profile has a relative balancing mark radius whose value is at least 0.08 times an outer radius of the impeller ( 14 ) having. Exhaust gas turbocharger for an internal combustion engine, with a rotatably mounted in a housing running gear ( 10 ), which is a wave ( 12 ) and at least one with the shaft ( 12 ) rotatably connected impeller ( 14 ) according to one of the preceding claims. Method for balancing a housing in an exhaust gas turbocharger about an axis of rotation ( 18 ) rotatably mounted to Laufzeugs ( 10 ), in which at a Radrücken ( 20 ) of an impeller ( 14 ) of the power tool ( 10 ) at least one balancing mark ( 22 . 24 ) is formed, characterized in that the balancing mark ( 22 . 24 ) in the circumferential direction ( 26 ) of the Radrücken ( 20 ) is formed at least substantially arcuately extending, wherein due to the formation of the balancing mark ( 22 . 24 ) this over an at least substantially in the extension direction ( 26 ) of the balancing mark ( 22 . 24 ) transition area ( 32 ) in the adjoining Radrücken ( 20 ), and wherein one through an intersection (S) of the transition region ( 32 ) with which at this subsequent Radrücken ( 20 ) running tangent ( 34 ) to the transition area ( 32 ) an angle (γ) with the Radrücken ( 20 ), which is at least substantially less than 15 degrees.

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