DE202015003359U1 - Abgastrubolader - Google Patents

Abstract

Exhaust gas turbocharger (1) - with a shaft (2) carrying a turbine wheel (3) and a compressor wheel (4); and - with a bearing housing (5), in which, for guiding the shaft (2), a roller bearing (6) is arranged, the at least one rolling bearing (7, 8) with an outer ring (9) and an inner ring (10, 11 ), between which a cage (13) with Wälzkörpertaschen (14) is arranged, in which rolling bodies (12) are guided, characterized in that - that the Wälzkörpertaschen (14), in the new condition of the cage (13), an having the rolling bodies adapted pocket macrogeometry training (15).

Description

The invention relates to a, in particular for the purpose of cooling and lubrication, supplied with engine oil exhaust gas turbocharger according to the preamble of claim 1.

Such an exhaust gas turbocharger has a rolling bearing provided in a bearing housing for the supercharger shaft, which comprises at least one roller bearing. An example of such a rolling bearing is in the DE 10 2012 211 891 A1 described. The rolling bearing has an outer ring and an inner ring pair. Between these rings, a cage with rolling bearing pockets is arranged in which rolling elements, such as balls, are guided. Such rolling bearings with speed characteristics "dm × n"of> 1.0 × 10 ⁶ mm / min require cages made of hot-treated steel. These can be mixed with a solid lubricant such. As silver, be coated to provide run-flat properties in marginal oil supply.

The rotor or shaft bearing has speed characteristics of up to 3 × 10 ⁶ mm × min ^-1 with specific polyformer rotor dynamics, including the representation of the 7 can be referenced.

If the cage is made without a silver layer, but it is performed with a higher surface hardness, what he z. B. can be nitrocarborated.

The inner rings of the rolling bearing are connected by Fugenlängspressverband with the rotor shaft. The outer ring is secured in the bearing housing against rotation or translation.

The 12 and 13 to illustrate the background of the invention is a section through a ball set / cage or, as in 13 shown, the contact angle "raceway / ball".

The ball cage is for this purpose provided with a plurality of cage main axis, evenly spaced, cylindrical ball pockets, which z. B. drilled, spindled or dip milled.

The disadvantage of such antifriction bearings or antifriction bearings is the fact that during the break-in phase due to the cage / ball dynamics a deformation of the ductile silver layer can occur until the cage pockets have geometrically adapted in the circumferential direction of the ball. After that it comes due to the "flow" of the silver alloy to the bead formation, which can protrude beyond the envelope diameter and break. The result is malfunctions and noises. The remaining silver is consumed relatively quickly, which has increased temperature loads. This is in addition to the 8th to 11 to refer to 8th the interaction of balls and cage clarifies and the 9 to 11 show the damage previously described in the break-in phase, where 9 a new layer of silver illustrates 10 the bead formation and 11 the condition with depleted silver layer and contact with the ground.

Due to the large degree of freedom of the rolling elements, in particular balls, in the roller pockets of the cage, it can lead to instability of the cage with a consequence of noise phenomenon and a reduction in efficiency, including on 14 to refer, which illustrates a deformed cage schematically simplified slightly.

It is therefore an object of the present invention to provide an exhaust gas turbocharger specified in the preamble of claim 1 species whose efficiency, robustness and its NVH behavior of its rolling bearing is improved over the prior art.

The solution of this problem is achieved by features of claim 1.

According to the principles of the present invention, the Wälzkörpertaschen, in the new state of the cage, on the rolling elements used, in particular balls, adapted pocket macrogeometry training.

With this inventive design is obtained in applications with high speed characteristics and transient dynamics, as they occur in the turbocharger area, an optimal ball-cage dynamics and cage guide in the outer ring.

Advantageously, the Taschenmakrogeometrie training can be machined, machined / without cutting or only without cutting produced. Depending on the accuracy requirements, the profile of the rolling bearing pockets can also be finalized only after successful heat treatment, such as by hard machining, such as grinding or lasers. Preferably, the rolling bearing pockets can be made by embossing, spindling (turning stylus) or grinding.

The dependent claims have advantageous developments of the invention to the content.

So it is possible to provide nano / microscopic lubrication / catch pockets to support the tribology of the bearings. These can be introduced by means of a process similar to vibratory finishing / trovalizing, but also by blasting analogously to the so-called "shot-peening" or by laser processing.

A possible production technology according to the invention can have the following features:
The cages are placed as bulk material in a first drum. In addition to the cages themselves are hard grains with specific shape in the container (eg pyramid, satellite, ball), (b) with hard particles (steel, ceramics, industry Diamond, corundum) provided paste. Thus, a targeted structuring of the surface is achieved under vibration (intensity and duration). The dents in the surface lead to a small edge bead, which are straightened in the subsequent Plateaunieren by means of turn other types of abrasives at best as part of the washing / cleaning of the cages. The cage can be designed with or without solid lubricant coating (silver, copper or similar) but also with lubricant inserts (eg sintered material).

Among the advantages of the invention is first to refer to the fact that optimal tribological and kinematic conditions already exist during commissioning of the rolling bearing, so that an enema effect is avoided.

Furthermore, there is an avoidance of flow of any solid lubricant layers, such as silver or, when not provided with solid lubricant cage, the base material, with a beading and disruptive fragments can be avoided.

Furthermore, advantageously results in an increased life of any solid lubricants.

Furthermore, there is the advantage of providing performance enhancing ball sorbital velocity profiles.

It is also advantageously possible to reduce mixed friction rates and thus extend the life of the cage.

A specifically adjustable degree of freedom of the cage is also preferably possible and leads to a favorable stability of the cage and reduces the occurrence of degenerating noise phenomena.

Nano / micro pockets can provide improved robustness during runflat operation.

Finally, advantageously results in a simplified assembly of the cage, since the balls are held positively, which also serves as a transport lock.

In claims 13 and 14, a roller bearing according to the invention is defined as independently tradable component of the exhaust gas turbocharger according to the invention.

Further details, features and advantages of the invention will become apparent from the following description of exemplary embodiments with reference to the drawing. It shows:

1 a sectional view of a body group of an exhaust gas turbocharger according to the invention,

2 an enlarged view of the rolling bearing of the exhaust gas turbocharger according to 1 .

3 a perspective view of a cage of the rolling bearing according to the invention,

4 a Wälzkörpertasche the cage according to 3 with a drawn coordinate system,

5 a Taschenmakrogeometrie-training of the cage according to the invention 3 .

6A one of the 5 Corresponding presentation of pocket macrogeometry training with drawing of further characteristics,

6B a schematic diagram of the cage with rolling elements to explain a Offsetranges,

7 a graph for explaining the speed or acceleration of a turbocharger with respect to the vehicle speed,

8th an explanation of the ball orbital speed in the load zone and the relative position of the ball to the rolling body pocket as a model idea,

9 - 11 schematically simplified representations of the initially described run-in phase and the damage occurrence in known roller bearings,

12 a section through a ball set / cage,

13 an explanation of a part of a known rolling bearing for explaining the pressure angle between the raceway and ball, and

14 a schematically slightly simplified representation of a cage deformation of a known rolling bearing.

In 1 is an embodiment of an exhaust gas turbocharger according to the invention 1 shown by his trunk group 1' is shown. A hull group means all basic components of the exhaust gas turbocharger 1 , however without the compressor housing and the turbine housing and peripheral components included in 1 purely for the sake of simplicity of illustration are not shown in an exhaust gas turbocharger according to the invention 1 Of course, however, are present.

Accordingly, the exhaust gas turbocharger 1 or his trunk group 1' a wave 2 on that a turbine wheel 3 and at the other end a compressor wheel 4 wearing.

The turbocharger 1 or the trunk group 1' also has a bearing housing 5 in which a rolling bearing 6 is arranged, which is the shaft 2 holds in the bearing housing in position or stores. The rolling bearing 6 exemplifies how this particular from the 2 yields at least one, but preferably two rolling bearings 7 . 8th on. The rolling bearings 7 and 8th have in the embodiment according to 2 , which is an angular contact ball bearing, in two-row design and in O arrangement as an example, an outer ring 9 and an inner ring at the in 2 illustrated embodiment in two inner rings 10 and 11 is divided. Between the outer ring 9 and the inner rings 10 and 11 (Inner ring pair) is at the in 2 illustrated special embodiment of the rolling bearing 6 one cage each 13 and 13 ' arranged, which, in particular from the 3 results in a plurality of rolling body pockets 14 includes. Like the representation of the 1 and 2 shows are in these rolling bearing pockets 14 rolling elements 12 arranged, which, as shown in the example, are formed as a ball. However, the invention also includes differently designed rolling elements or rolling bearings.

As explained above, it is inventively provided that the rolling body pockets 14 , in new condition of a cage 13 , one to the rolling elements, in particular balls 12 , customized pocket macrogeometry training 15 in particular from the illustration of 5 results.

In 4 is to illustrate the active principle according to the invention and the Taschenmakrogeometrie training according to the invention 15 a cage coordinate system 16 whose zero point O in the center M of in 4 illustrated Wälzkörpertasche 14 is arranged. Here, the coordinates X, α denote the circumferential direction, Y, β the radial direction and Z, γ the axial direction.

Since balls are provided as rolling elements in the case of the particularly preferred embodiment shown in the figures, the rolling-element pockets are provided 14 designed as ball pockets, which, however, according to the invention in the circumferential direction X could also be designed slot-shaped.

The constructive games between ball 12 and cage wall 17 (S. 5 ) in the axial direction Z, in the circumferential direction X and in the radial direction Y are of the dimensions of the rolling bearing 7 . 8th , in particular of the dimensions of the cage 13 and the balls 12 depending on the operation, but also on the viscosity of the operating temperature engine oil.

The function of the ball-cage dynamics is based on the well-known laws of damping and tribology (elasto-hydro-dynamics and leakage or squish flow).

Particularly preferred embodiments of the roller bearing according to the invention or of the exhaust gas turbocharger according to the invention have balls 12 with a ball diameter of 2.5 mm to 3.5 mm and a pitch circle diameter of 9 to 12 mm. Under the pitch circle here is an imaginary circle to understand, the center is pierced perpendicularly from the axis of rotation of the rolling bearing, and the centers of the rolling elements 12 a series circumferentially intersects or connects to each other.

The wall thickness W (s. 3 ) of the cage 13 is preferably designed in a range of 30% ± 4% of the ball diameter.

The average (neutral) diameter of a cage 13 (da + di) / 2 preferably differs from the circle diameter (sphere center) by values between 0% to 5 ° / rev.

The "center" of the rolling element pocket 14 is defined in relation to the pitch circle TK (sphere) in a radial offset range OR of 0% to -3%. By such a negative offset results in an arrangement of the centers M13 of the ball pockets within the pitch circle diameter TK, including the representation of 6B to refer. This results in three positive effects: First, the impressions of the ball 12 in the ball bag 14 an at least slight deformation of the ball pocket 14 , On the other hand, the inertia of the cage 13 . 13 ' reduced so that, first, a high acceleration is shortened in time and second, the pulses between balls 12 and cage 13 . 13 ' appear less pronounced.

With reference to 6A It should be emphasized that the osculation, which is the quotient of the diameter of the rolling body pocket 14 and the diameter of the rolling element 12 , in particular ball, is preferably in the range of 0.9 to 1.1.

The ratio of widths "BX" to "BZ" ("round" or "long hole") is preferably 1: 1 to 1.2: 1.

The games or the degree of freedom of the ball 12 result from "BX" and "BZ". The narrowest distances between the rolling element pockets 14 "BX1,2" or "BZ1,2" may be smaller than the ball diameter. However, this only insofar as that a proper filling of the balls 12 taking into account the elasticity of the materials, in particular Si3N4 and steel is possible (analogous to a transport lock, in which the balls are held by a 0.02 mm to 0.05 mm smaller "Schnappwulst").

Z:

2% bis 5% des Kugeldurchmessers;

X:

2% bis 5% bzw. bei ovaler Ausführungsform 7% bis 15% des Kugeldurchmessers;

Y:

2% bis 5% des Kugeldurchmessers.

Particularly preferred values for the game "delta d" in the Wälzkörpertasche 14 are:

Z:

2% to 5% of the ball diameter;

X:

2% to 5% or in the case of an oval embodiment 7% to 15% of the ball diameter;

Y:

2% to 5% of the ball diameter.

The ratio of the osculation in the axial direction x to the circumferential direction z is between 1: 1 and 1: 1.2.

In addition to the above written disclosure of the invention is hereby to supplement this explicitly on the graphic representation in the 1 to 14 Referenced.

LIST OF REFERENCE NUMBERS

1

turbocharger

2

wave

3

turbine

4

compressor

5

bearing housing

6

roller bearing

7, 8

roller bearing

9

outer ring

10, 11

inner ring

12

Rolling elements, in particular ball

13, 13 '

Cage

14

Wälzkörpertasche, in particular ball bag

15

Bag macrogeometry training

16

Cage coordinate system

17

Cage pocket wall

TK

pitch circle

OR

offset Range

M12

Ball center

M13

Cage center

kä

Cage

Ku

Bullet

N / A

intermediate lag

Ge

Geschwindigkeitsdiff. Ball cage

Dr

Direction of rotation of the cage

La

Load angle at pure radial load

A

Entering a new ball in the

B

Entering a new ball in the

C

Load zone / bracing / Synchronization / relaxing / Management change

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

• DE 102012211891 A1 [0002]

Claims (14)

Exhaust gas turbocharger ( 1 ) - with a wave ( 2 ), which is a turbine wheel ( 3 ) and a compressor wheel ( 4 ) wearing; and - with a bearing housing ( 5 ), in which, to guide the wave ( 2 ), a rolling bearing ( 6 ) is arranged, the at least one rolling bearing ( 7 . 8th ) with an outer ring ( 9 ) and an inner ring ( 10 . 11 ), between which a cage ( 13 ) with rolling-element pockets ( 14 ) is arranged, in which rolling elements ( 12 ), characterized in that - the rolling-element pockets ( 14 ), when the cage is new ( 13 ), adapted to the rolling bodies pocket macrogeometry training ( 15 ) exhibit. Exhaust gas turbocharger according to claim 1, characterized in that the pocket macro geometry design ( 15 ) by a cage coordinate system ( 16 ), which has its zero point (O) in the center (M) of the rolling body pockets ( 14 ) and which is defined in the circumferential direction by the coordinates X, in the radial direction by the coordinates Y and in the axial direction by the coordinates Z, wherein the constructional games between the rolling elements ( 12 ) and a cage pocket wall ( 17 ) in the circumferential direction and radial direction of the dimensions of the rolling bearing ( 7 . 8th ) are dependent. Exhaust gas turbocharger according to claim 1 or 2, characterized in that the rolling bodies ( 12 ) are formed as balls. Exhaust gas turbocharger according to claim 3, characterized in that the diameter of the balls ( 12 ) Is 2.5 mm to 3.5 mm. Exhaust gas turbocharger according to claim 3 or 4, characterized in that the pitch circle diameter of the rolling bearing ( 7 . 8th ) Is 9 mm to 12 mm. Exhaust gas turbocharger according to one of claims 3 to 5, characterized in that the wall thickness (W) of the cage ( 13 ) Is 30% ± 4% of the ball diameter. Exhaust gas turbocharger according to claim 5 or 6, characterized in that the average (neutral) cage diameter differs by 0% to 5% of the pitch diameter (ball center). Exhaust gas turbocharger according to one of claims 5 to 7, characterized in that the center of the rolling bearing pockets ( 14 ) with respect to the pitch circle (TK) in a radial offset range of 0% to -3%. Exhaust gas turbocharger according to one of claims 3 to 8, characterized in that the osculation is between 0.9 and 1.1. Exhaust gas turbocharger according to one of claims 2 to 9, characterized in that the ratio of widths "BX" to "BZ" is in a range of 1: 1 to 1.2: 1. Exhaust gas turbocharger according to one of claims 2 to 10, characterized in that the play of the rolling elements ( 12 ) in the rolling body pockets ( 14 ) in the axial direction (Z) is 2% to 5% of the ball diameter, in the circumferential direction "X" 2% to 5% or in the oval design 7% to 15% of the ball diameter and in the radial direction "Y" 2% to 5% of Ball diameter is. Exhaust gas turbocharger according to one of claims 2 to 11, characterized in that the ratio of the osculation in the axial direction "Z" to the circumferential direction "X" is between 1: 1 and 1: 1.2. Rolling bearing for a shaft ( 2 ) of an exhaust gas turbocharger ( 1 ) with at least one rolling bearing ( 7 . 8th ), which has an outer ring ( 9 ) and an inner ring ( 10 . 11 ), between which a cage ( 13 ) with rolling-element pockets ( 14 ) is arranged, in which rolling elements ( 12 ) are guided, characterized in that the rolling body pockets ( 14 ), when the cage is new ( 13 ), one to the rolling elements ( 12 ) adapted pocket macrogeometry training ( 15 ) exhibit. Rolling bearing according to claim 13, characterized by at least one of claims 2 to 11.

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