DE102010054939A1 - Bearing arrangement for a turbocharger and turbocharger - Google Patents

Abstract

The invention relates to a bearing arrangement (3, 63, 123, 183) for a turbocharger (1, 61, 121, 181), comprising a bearing housing (11, 71, 131, 191) extending in an axial direction, one inside the bearing housing (11, 71, 131, 191) arranged rolling bearing (13, 73, 133, 193) with an outer bearing ring (15, 17, 75, 77, 135, 137, 195, 197) and a number of rolling elements (21, 81 , 101, 161), and an axially extending shaft (9, 69, 129, 189) rotatably mounted within the bearing housing (11, 71, 131, 191). It is provided that the shaft (9, 69, 129, 189) comprises a rolling body raceway (25, 27, 85, 87, 145, 147, 205, 207) for guiding the rolling bodies (21, 81, 101, 161). Furthermore, the invention relates to a turbocharger (1, 61, 121, 181), with such a bearing assembly (3, 63, 123, 183). Such a bearing assembly (3, 63, 123, 183) allows for easy installation and low cost, the safe storage of a shaft (9, 69, 129, 189) in a turbocharger (1, 61, 121, 181).

Description

Field of the invention

The invention relates to a bearing arrangement for a turbocharger, comprising a bearing housing, a bearing arranged inside the bearing housing with an outer bearing ring and a number of rolling elements, and a rotatably mounted within the bearing housing, axially extending shaft.

Furthermore, the invention relates to a turbocharger with an aforementioned bearing assembly.

Background of the invention

A turbocharger is usually used to increase the performance of internal combustion engines through the use of exhaust gas energy. The turbocharger consists of a compressor and a turbine, which are connected to each other via a shaft mounted within a bearing housing shaft.

In operation, the turbine is rotated by an exhaust gas flow and drives the compressor via the shaft, which sucks and compresses air. The compressed air is conducted into the engine, whereby a large amount of air enters the cylinders due to the increased pressure during the intake stroke. As a result, the oxygen content required for the combustion of fuel increases accordingly, so that more oxygen enters the combustion chamber of the engine at each intake stroke.

This leads to an increase in the maximum torque, whereby the power output, ie the maximum power at a constant working volume, is increased. This increase allows in particular the use of a more powerful motor with approximately the same dimensions or alternatively allows a reduction of the motor dimensions, so achieving a comparable performance in smaller and lighter machines.

Since the shaft rotates at high rotational speed during operation of a turbocharger, its safe storage is necessary to allow trouble-free operation of the turbocharger.

From the DE 689 08 244 T2 is designed as a bearing support assembly bearing unit for a turbocharger of the type mentioned above. Within a bearing housing, a shaft is arranged. The bearing of the shaft within the bearing housing via a pair of ball bearings designed as rolling bearings. The ball bearings consist in each case of an outer bearing ring and an inner bearing ring, wherein the inner bearing rings are fixedly secured to the shaft.

By the aforementioned embodiment, the safe storage of a shaft of a turbocharger can be achieved even at increased speeds of the shaft. However, the use of a plurality of required separate bearing components and the associated costly installation effort is no permanent solution for a bearing assembly or a turbocharger.

Object of the invention

It is therefore a first object of the invention to provide a comparison with the prior art improved bearing assembly that allows for easy installation and low cost secure storage of a shaft in a turbocharger.

A second object of the invention is to provide a turbocharger with such a bearing assembly.

Solution of the task

The first object of the invention is achieved by a bearing assembly for a turbocharger, comprising a bearing housing extending in an axial direction, a rolling bearing disposed within the bearing housing with an outer bearing ring and a number of rolling elements, and a rotatably mounted within the bearing housing itself axially extending shaft. In this case, it is provided that the shaft comprises a rolling body raceway for guiding the rolling bodies.

The invention takes into account that by using a plurality of separate bearing components in addition to an increased installation effort and a deterioration of the bearing components and thus the function of the turbocharger is to be feared. This applies in particular with regard to the usually used inner bearing rings which have corresponding raceways for guiding rolling elements on their outer circumference. During assembly, the inner bearing rings are pushed onto the shaft and must be pressed onto them so that no rotation relative to the shaft is possible during operation. When pressing the bearing rings are compressed so that the axial distance between the Wälzkörperlaufbahnen shortened and thus the wave play is changed. Furthermore, the diameter of the Wälzkörperlaufbahnen and thus the bearing clearance change.

In addition, when the inner bearing rings are pressed in, they may be misaligned on the shaft. It is possible, for example, that they do not align coaxially with the shaft and with respect to one another, resulting in undesired seating at the axial contact points between the two during the balancing operation as well as later during operation Can lead bearing rings or the bearing seats. In addition, the balancing quality can deteriorate over the life of the bearing and thus lead to increased wear of the bearing components. In any case, such a trouble-free function of a turbocharger can not be guaranteed.

The invention finally recognizes that the aforementioned problems can be overcome, surprisingly, when the shaft comprises a rolling body raceway for guiding the rolling bodies. The use of separately mounted inner bearing rings can be dispensed with altogether. In other words, the shaft itself assumes the function of the inner bearing rings, so that a safe mounting of the shaft in a turbocharger can be achieved by such a configuration with low cost and assembly costs.

In addition, by dispensing with separate inner bearing rings, the sum of the component tolerances can be reduced. The usually adding shape and position errors of the inner bearing rings on the shaft can be avoided, whereby the tolerance is lower overall.

The shaft can be made of different materials, in particular temperature-stable and corrosion-resistant materials are suitable. The shaft may for example be made in one piece by means of a forming process, a machining process or a casting process. Alternatively to the one-piece production, a multi-part production is possible. The rolling body raceway is in this case integrated in the lateral surface of the shaft and can be introduced, for example, directly in the manufacture of the shaft in one step in the lateral surface. Alternatively, the rolling body raceway can be subsequently introduced into the lateral surface in a step subsequent to the manufacture of the shaft main body. In order to ensure the necessary stability of the shaft, we preferably subject it to post-processing after production.

The shaft is rotatably mounted in the installed state within a bearing housing. For this purpose, the bearing housing is preferably formed as a hollow cylinder. Due to the high loads during operation of a turbocharger, temperature-resistant and corrosion-resistant metallic materials are particularly suitable for producing the bearing housing. The bearing housing is formed in particular with a receiving bore for the other components of the bearing assembly, such as the rolling bearing.

The rolling bearing or the individual rolling bearing components are expediently made of temperature and corrosion resistant materials, such as hardened steels or ceramics. As a rolling bearing, the common types of bearings are basically used, such as cylindrical roller bearings or tapered roller bearings. Particularly suitable are ball bearings, such as in particular double row angular contact ball bearings. To guide the rolling elements of a double row angular ball bearing expediently two axially spaced Wälzkörperlaufbahnen are introduced in the lateral surface of the shaft.

The rolling bearing is further formed with at least one outer bearing ring, on the inner circumference of a Wälzkörperlaufbahn is introduced, which also serves to guide and positioning of the rolling elements. Here, both a one-piece and a multi-part production of the outer bearing ring is possible. In a multi-part manufacturing, the outer bearing rings, for example, abut each other and thus prevent axial displacement of the bearings on the shaft. Alternatively, the outer bearing rings, for example, by means of a spring member axially spaced apart.

Between the outer diameter of the outer bearing ring and the inner circumference of the bearing housing in particular a gap, for example as a circumferential outer race ring gap formed for a so-called Quetschölfilm. The quenching oil film assumes the function of the vibration damper and prevents unwanted contact between the outer bearing ring and the bearing housing.

In order to supply the intermediate space with oil, a number of supply bores can be introduced within the bearing housing, via which oil from the engine oil circuit can be metered into the intermediate space. The supply holes are for this purpose in particular with a number of the outer circumference of the outer race ring circumferential grooves in a communicating connection. Accordingly, the grooves can be supplied with oil via the supply bores. Starting from the grooves, the oil can distribute in the axial direction over the circumference of the outer bearing ring, so that forms a uniform oil film between the outer bearing ring and the inner wall of the bearing housing. The number of supply holes and the grooves here is basically not limited and can be adjusted, for example, the dimensions of the bearing housing and the thickness of Quetschölfilms.

Furthermore, an outlet bore is preferably additionally introduced into the bearing housing, which is communicatively connected to a drain groove running around the outer bearing ring on its outer circumference. In this way, it is ensured that the over the supply bore the Intermediate space supplied oil can flow continuously.

Alternatively, the outer bearing rings can be guided by an additional support ring in the bearing housing. In this case, the carrier ring is embedded in the intermediate space. In this case, the carrier ring preferably has on its outer circumference a number of peripheral grooves which, in the installed state, communicate with the supply bores of the bearing housing in a manner communicating. The quenching oil film is then formed correspondingly in the space between the outer periphery of the carrier ring and the inner wall of the bearing housing. When using a carrier ring is suitably introduced in this introduced on its outer circumference drainage communicating with an outlet bore in connection and allows corresponding to the oil drain.

In order to position the rolling bearing against rotation within the bearing housing, securing elements can be used. In principle, a multiplicity of securing elements is conceivable which can withstand the forces acting during operation of a turbocharger and which enable a rotationally secure arrangement of the outer bearing ring within the bearing housing. The security elements, the number of which is not limited in principle, may be formed, for example, as backup pins or securing bolts that can be inserted into holes provided for this purpose within the bearing housing. Alternatively, the securing elements can be designed as springs, which can then engage, for example, in recesses or grooves provided for this purpose.

In an advantageous embodiment of the invention, the shaft consists of a steel, at least in the region of the rolling body track. In principle, different steels or metallic materials can be used here. In particular, an alloyed bearing steel is suitable. In this case, for example, a roller bearing steel type 81MoCrV42-16 can be used, which in particular due to its temperature stability and corrosion resistance, the necessary conditions for use in turbochargers. The properties of the metallic material or of the rolling bearing steel can be influenced by the choice of the alloy components or by the composition. Basically, it is possible to manufacture the whole while from a bearing steel. Alternatively, a rolling bearing steel can also be used only at the points of the rolling body raceways.

In a further advantageous embodiment of the invention, the shaft is composed of a number of axially adjacent shaft sections. The individual shaft sections can be welded together prior to assembly of the bearing assembly. The multi-part design allows, for example, the controlled introduction of recesses in the shaft. These recesses provide an air volume within the shaft which, when the shaft is installed in the turbocharger, reduces the heat conduction from the turbine wheel to the rolling bearing.

In particular, by using a plurality of shaft sections, the costs associated with the production of the shaft or during the production of the bearing arrangement can be reduced. This is made possible in particular by the fact that the shaft sections can be made of different materials. Here, the shaft sections in which the Wälzkörperlaufbahnen are introduced, preferably made of a bearing steel, which has the necessary stability. For the other shaft sections requirement-specific material and correspondingly cheaper shaft material can be used.

In order to connect the shaft sections with each other, these are preferably welded together. Welding methods are suitable in this case in particular because, when they are used, it is also possible to use materials with different physical properties, such as, for example, As steel with aluminum to connect.

Preferably, the shaft comprises an inner recess. The inner recess may be formed as a cavity that provides an additional volume of air. As a result, for example, the heat conduction from the turbine to the bearing can be reduced. Furthermore, the recess can be used to accommodate so-called welding ejection, which occurs when the shaft is connected to the turbine wheel or even when several shaft sections are connected to one another and can then be collected within the recesses. In principle, a recess can also be made in the turbine wheel. The same applies to a multi-part design of the shaft for the individual shaft sections, which can also be formed in each case with a recess. As a result, the internal air volume increases further and the thermal conductivity is further reduced.

Preferably, the shaft on the front side a shaft journal for centering and attachment to a turbine wheel. The shaft journal is preferably designed as an axially extending pin, which can engage in the installed state in the bore of a turbine wheel. Thus, even before the welding of the components, a connection between them is possible, which simplify the subsequent welding process. Basically, here is the training of a Pint on the turbine wheel possible, which then engages in a bore on the front side of the shaft.

In this case, it is also possible in principle for a recess to be introduced in the journal, which provides an air volume within the shaft. Thus, the heat conduction from the turbine wheel to the rolling bearing can also be reduced by means of the pin.

Conveniently, the outer bearing ring comprises a spray oil hole for lubricant application of the rolling bearing. The spray oil holes are in this case connected to the grooves in the outer ring. The oil can pass from the grooves through the spray oil holes in the storage room and be used in this way for lubrication and cooling.

More preferably, the shaft comprises on its outer circumference a number of grooves for positioning of sealing elements. The grooves can be introduced into the outer circumference of the shaft both on the compressor side and on the turbine side, so that a sealing effect is achieved on both sides of the shaft. In this way, the required lubrication of the positioned inside the bearing housing bearing can be ensured, which is achieved for example via spray oil holes.

More preferably, the shaft comprises an oil separator. The oil separator may for example be attached to the shaft as a separate component or integrated into the shaft. In particular, the oil separator is designed as one which operates by utilizing the centrifugal force principle.

The second object of the invention is achieved by a turbocharger comprising a compressor wheel, a turbine wheel, and a bearing assembly according to the aforementioned embodiments, wherein the compressor wheel and the turbine wheel are arranged at the opposite ends of the shaft. It is provided that the shaft is welded to the turbine wheel.

As already explained, the turbine wheel of the turbine of a turbocharger is set in rotation by an exhaust gas flow and drives the compressor via the shaft. The compressor draws in air and compresses it. The compressor operates continuously and is characterized by low pressure increase and a high volume throughput. The compressed air is conducted into the engine, whereby a large amount of air enters the cylinders due to the increased pressure during the intake stroke. As a result, the oxygen content required for the combustion of fuel increases accordingly, so that more oxygen enters the combustion chamber of the engine at each intake stroke.

In order to achieve a secure attachment of the turbine wheel on the shaft and thus to ensure a connection between the compressor and the turbine wheel, the shaft is welded to the turbine wheel. For this purpose, different welding methods are suitable.

For example, a friction welding method can be used. Friction welding allows a secure connection of components both with the same and with different material combinations. This is a pressure welding process, whereby the heating of the parts to be joined takes place by mechanical friction. The heating is usually generated by a movement between a rotating and a stationary component, which are combined under force without additional material.

As an alternative to the friction welding method, the shaft can also be connected to the turbine wheel by means of an electron beam welding method. This method, for example, due to the high energy density, which is introduced into the welding zone, allows the joining of a variety of different materials, such as high-melting metals. Electron beam welding enables high welding speeds with extremely deep and narrow seams. Due to the small seam widths and the high parallelism, the delay can be kept extremely small.

Furthermore, for example, a laser beam welding is conceivable, which can connect components with high welding speed, narrow and slim weld shape and low thermal distortion. The laser beam welding is usually performed without feeding a filler material.

Preferably, the turbine wheel is pressed onto the shaft. This process is expediently preceded by the welding process. For this purpose, the shaft is formed on the turbine side, for example, with a shaft journal extending in the axial direction, which is pressed into a bore in the turbine wheel. By means of this interference fit, a connection between the shaft and the turbine wheel is possible even before welding, so that the two components subsequently only have to be welded together at the preferably planar contact points. Of course, alternatively, the turbine wheel with a pin and the shaft may be formed with a bore on its end face, so that the shaft is pressed in the turbine wheel.

The compressor wheel is expediently fastened to the shaft by means of a nut. The For this purpose, the compressor wheel is pushed onto the shaft during assembly and finally jammed there by means of the nut. In this way, a secure connection between the compressor and the shaft is guaranteed.

In principle, the bearing components of the bearing cartridge can be preassembled and pushed starting from the turbine side into the bearing housing. This allows a delivery of the storage cartridge with less effort and a low installation costs for the customer.

Further advantageous embodiments can be found in the directed to the bearing assembly subclaims that can be analogously transmitted to the turbocharger.

Short description of the drawing

In the following, embodiments of the invention will be explained in more detail with reference to a drawing. The show 1 to 4 each a turbocharger with a bearing assembly in a longitudinal section.

Detailed description of the drawing

1 shows a turbocharger 1 with a bearing arrangement 3 , The turbocharger has a compressor wheel 5 and a turbine wheel 7 at the opposite ends of an axially extending shaft 9 are arranged.

The wave 9 is part of the bearing arrangement 3 and within a likewise axially extending bearing housing 11 rotatably mounted. Furthermore, the bearing arrangement comprises 3 one inside the bearing housing 11 arranged rolling bearing 13 with two axially adjacent outer bearing rings 15 . 17 , The outer bearing rings 15 . 17 are by means of a preloaded spring element arranged between them 19 spaced apart.

The rolling bearing 13 also has trained as balls rolling elements 21 on, in rows, each in cages 23 are held. The rolling elements are guided 21 each in Wälzkörperlaufbahnen 25 . 27 that is in the lateral surface of the shaft 9 are integrated. The rolling element raceways 25 . 27 are introduced directly into the lateral surface during production of the shaft in one step. This can be dispensed with the use of separately mounted inner bearing rings, since the shaft 9 the function of the inner bearing rings takes over.

As a result, the effort during assembly, in which the inner bearing rings must be pushed onto the shaft and pressed onto this reduced. Furthermore, the axial distance between the Wälzkörperlaufbahnen remains 25 . 27 always the same size, so that the wave play does not change.

In addition, by dispensing with separate inner bearing rings, the sum of the component tolerances can be reduced. The usually adding shape and position errors of the inner bearing rings on the shaft 9 can thus be avoided, whereby the tolerance is lower overall.

The entire wave 9 is made in one piece from a temperature-resistant bearing steel. It is by means of a friction welding process with the turbine wheel 7 welded, creating a secure connection between the shaft 9 and the turbine wheel 7 is reached.

In addition, both are in the shaft 9 as well as in the turbine wheel 7 recess 29 . 31 brought in. The recesses 29 . 31 provide an air volume so that the heat conduction from the one turbine wheel 7 to the rolling bearing 13 during operation of the turbocharger 1 is reduced. Furthermore, they provide space for welding ejection during machining of the shaft.

On the turbine wheel 7 opposite side is the shaft 9 with the compressor wheel 5 connected. This is the compressor wheel 5 pushed onto the shaft and there by means of a mother 33 jammed.

On the outer circumference of the shaft 9 are grooves 35 for the positioning of sealing elements 37 brought in. The sealing elements 37 dense both sides of the compressor wheel 5 as well as on the turbine wheel side 7 against leakage and contamination.

For mounting the turbocharger, the bearing components can be pre-assembled and starting from the turbine side into the bearing housing 11 be pushed. As the outer diameter of the outer bearing rings 15 . 17 is slightly smaller than the inner diameter of the bearing housing 11 , arises between the bearing housing 11 and the outer bearing rings 15 . 17 a gap-shaped gap 39 , The gap 39 is about supply hole 41 in the bearing housing 11 subjected to oil, so that there forms a Quetschölfilm. The supply holes 41 . 42 stand with grooves 43 . 44 on the outer circumference of the outer bearing rings 15 . 17 communicating. Furthermore, the oil from the grooves 43 . 44 Starting with the grooves 43 connected spray oil holes 45 . 46 distributed in the bearings and can be used for lubrication. To drain the oil is an outlet hole 47 includes.

In addition, it is on the shaft 9 an oil separator 49 attached with centrifugal force principle.

In 2 is another turbocharger 61 with a bearing arrangement 63 shown. The turbocharger 61 has a compressor wheel 65 and a turbine wheel 67 at the opposite ends of an axially extending shaft 69 are arranged. The entire wave 69 is also in 2 manufactured in one piece from a temperature-resistant steel.

Because the function and the individual components of the turbocharger 61 in 2 essentially those of the turbocharger 1 in 1 Accordingly, at this point, the detailed description and illustration in 1 referred to, which in the following can be transferred analogously.

In contrast to 1 is the turbine wheel 67 by electron beam welding to the shaft 69 connected. This is the turbine wheel 67 on the wave 69 pressed. The turbine wheel 67 has a corresponding hole 111 on, in which the formed on the front side of the shaft shaft journal 113 the shaft is pressed. The shaft journal 113 is formed as a pin extending in the axial direction.

Following are the turbine wheel 67 and the wave 69 only on the flat contact surfaces 115 of the turbine wheel 67 and the wave 69 welded by an electron beam.

Further, the wave 69 on the turbine wheel 67 opposite side with the compressor wheel 65 by means of a mother 93 jammed. On the same side is on the shaft 69 additionally an oil separator 109 attached with centrifugal force principle.

3 shows another turbocharger 121 with a bearing arrangement 123 , The turbocharger 121 also has a compressor wheel 125 and a turbine wheel 127 at the opposite ends of an axially extending shaft 129 are arranged. The wave 129 is within a likewise axially extending bearing housing 131 rotatably mounted.

For this purpose, the bearing arrangement 123 one inside the bearing housing 131 arranged rolling bearing 133 with two axially adjacent outer bearing rings 135 . 137 on. The outer bearing rings 135 . 137 are by means of a preloaded spring element arranged between them 139 spaced apart. The rolling bearing 133 also has trained as balls rolling elements 141 on, in rows, each in cages 143 are held. The rolling elements are guided 141 each in Wälzkörperlaufbahnen 145 . 147 that is in the lateral surface of the shaft 149 are integrated.

When installed, between the outer diameter of the outer bearing rings 135 . 137 and the bearing housing 131 a gap-shaped gap 159 formed, which has two supply holes 161 in the bearing housing 131 is applied with oil. Here, a quenching oil film forms in the intermediate space. The supply holes 161 . 162 stand with grooves 163 . 164 on the outer circumference of the outer bearing rings 13 . 137 communicating. From the grooves 163 . 164 starting from the oil in addition to spray oil wells 165 . 166 distributed in the bearings and can be used for lubrication. To drain the oil is still an outlet hole 167 includes.

The difference of the turbocharger 121 to the turbochargers already shown 1 . 61 exists in the nature of the wave 129 , The wave 129 is from different wave sections 171 . 173 . 175 composed. The rolling element raceways 145 . 147 are accordingly only in one shaft section 173 brought in. The shaft section 173 accordingly assumes the function of the otherwise required inner bearing rings.

The shaft section 173 is made of temperature-resistant steel, whereas the two axially adjacent shaft sections 171 . 175 requirement-specific are made of a cheaper metallic material.

The wave sections 171 . 173 . 175 have axially inwardly extending recesses 176 . 177 . 178 . 179 on. The inner recesses 176 . 177 . 178 . 179 are designed as cavities that provide an additional volume of air available. Due to this, they cause a reduction of the heat conduction from the turbine wheel 127 effect to the camps. Also the turbine wheel 127 has a recess 180 which additionally increases the air volume and thus reduces the heat conduction.

The wave sections 171 . 173 . 175 are here welded together. After welding the shaft sections 171 . 173 . 175 is finally the shaft section 175 with the turbine wheel 127 welded. This is how the turbocharger 1 according to 1 a friction welding used.

The welded shaft sections 171 . 173 . 175 or the wave 129 finally gets to the side of the shaft section 175 by means of a friction welding process with the turbine wheel 127 welded. Also the turbine wheel 127 has an inner recess 180 on that the volume of air to reduce the heat conduction from the turbine wheel 127 to the rolling bearing 133 during operation of the turbocharger 121 further reduced.

For fastening the compressor wheel 125 on the shaft 129 this is at the turbine wheel 127 opposite side of the shaft 129 postponed to this and there by means of a mother 153 attached. Furthermore, on the shaft 129 an oil separator 169 attached, which works by means of the centrifugal active principle.

In 4 is another turbocharger 181 with a bearing arrangement 183 shown. The turbocharger 181 has a compressor wheel 185 and a turbine wheel 187 at the opposite ends of an axially extending shaft 189 are arranged. The wave 189 is within a likewise axially extending bearing housing 191 rotatably mounted.

The bearing arrangement 183 further includes a within the bearing housing 191 arranged rolling bearing 193 with two axially adjacent outer bearing rings 195 . 197 , which, as in the previous figures by means of a prestressed spring element arranged between them 199 spaced apart from each other. The rolling bearing 193 also has trained as balls rolling elements 201 on, in rows, each in cages 203 are held. The rolling elements 201 are in rolling element raceways 205 . 207 guided.

As the function of the individual components of the turbocharger 181 in 4 essentially corresponds to those of the embodiments described above, reference is made at this point to the local detailed description, which can be transmitted in the following mutatis mutandis.

As well as in 3 is the wave 189 from three separate shaft sections 237 . 239 . 241 manufactured. The wave sections 237 . 239 . 241 consist of different materials, with the shaft section 239 Made of temperature-resistant steel. The other two shaft sections 237 . 241 consist of a less expensive metallic material.

The rolling element raceways 205 . 207 are accordingly only in the shaft section 239 introduced, which consists of the steel. The shaft section 239 takes over the function of the inner bearing rings, so that both the costs and the assembly costs are reduced and increases the accuracy.

The shaft section 239 is each end face with two axially extending shaft journals 243 . 245 educated. These shaft journals 243 . 245 grab built state in the holes 247 . 249 , respectively at the axial abutment points of the shaft sections 237 . 241 are formed. The shaft cones 243 . 245 be in the mounting accordingly in the holes 247 . 249 pressed. Thus, even before the welding of the components, a connection between them is possible, which simplify the subsequent welding process. The welding of the individual shaft sections to each other due to the interference fit between this only at the contact surfaces 251 . 253 ,

For attachment to the turbine wheel 187 has the shaft section 241 at the hole 249 opposite side in addition a shaft journal 255 up into the hole 257 of the turbine wheel 187 pressed. After pressing the two components, or the shaft 189 and the turbine wheel 187 at the contact points 259 welded. For this purpose, a laser beam welding is used. whereby components connect with high welding speed, narrow and slim weld form and with low thermal distortion. The laser beam welding is performed without feeding a filler material.

For fastening the compressor wheel 185 on the shaft 189 this is at the turbine wheel 187 opposite side of the shaft 189 postponed to this and there by means of a mother 213 jammed. In this way, there is also a secure connection between the compressor wheel 185 and the wave 189 guaranteed. In addition, it is on the shaft 189 an oil separator 229 attached, which works by means of the centrifugal active principle.

LIST OF REFERENCE NUMBERS

1

turbocharger

3

bearing arrangement

5

compressor

7

turbine

9

wave

11

bearing housing

13

roller bearing

15

outer bearing ring

17

outer bearing ring

19

spring element

21

rolling elements

23

Cage

25

rolling body

27

rolling body

29

recess

31

recess

33

mother

35

groove

37

sealing element

39

gap

41

supply hole

42

supply hole

43

groove

44

groove

45

Oil-drilling

46

Oil-drilling

47

outlet bore

49

oil separator

61

turbocharger

63

bearing arrangement

65

compressor

67

turbine

69

wave

71

bearing housing

73

roller bearing

75

outer bearing ring

77

outer bearing ring

79

spring element

81

rolling elements

83

Cage

85

rolling body

87

rolling body

89

recess

91

recess

93

mother

95

groove

97

sealing element

99

gap

101

supply hole

102

supply hole

103

groove

104

groove

105

Oil-drilling

106

Oil-drilling

107

outlet bore

109

oil separator

111

drilling

113

shaft journal

115

contact area

121

turbocharger

123

bearing arrangement

125

compressor

127

turbine

129

wave

131

bearing housing

133

roller bearing

135

outer bearing ring

137

outer bearing ring

139

spring element

141

rolling elements

143

Cage

145

rolling body

147

rolling body

153

mother

155

groove

157

sealing element

159

gap

161

supply hole

162

supply hole

163

groove

164

groove

165

Oil-drilling

166

Oil-drilling

167

outlet bore

169

oil separator

171

shaft section

173

shaft section

175

shaft section

176

recess

177

recess

178

recess

179

recess

180

recess

181

turbocharger

183

bearing arrangement

185

compressor

187

turbine

189

wave

191

bearing housing

193

roller bearing

195

outer bearing ring

197

outer bearing ring

199

spring element

201

rolling elements

203

Cage

205

rolling body

207

rolling body

213

mother

215

groove

217

sealing element

219

gap

221

supply hole

223

groove

225

Oil-drilling

227

outlet bore

229

oil separator

237

shaft section

239

shaft section

241

shaft section

243

shaft journal

245

shaft journal

247

drilling

249

drilling

251

contact area

253

contact area

255

shaft journal

257

drilling

259

contact area

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 68908244 T2 [0007]

Claims (10)

Bearing arrangement ( 3 . 63 . 123 . 183 ) for a turbocharger ( 1 . 61 . 121 . 181 ), comprising a bearing housing extending in an axial direction (US Pat. 11 . 71 . 131 . 191 ), one inside the bearing housing ( 11 . 71 . 131 . 191 ) arranged rolling bearing ( 13 . 73 . 133 . 193 ) with an outer bearing ring ( 15 . 17 . 75 . 77 . 135 . 137 . 195 . 197 ) and a number of rolling elements ( 21 . 81 . 101 . 161 ), as well as one within the bearing housing ( 11 . 71 . 131 . 191 ) rotatably mounted, axially extending shaft ( 9 . 69 . 129 . 189 ), characterized in that the shaft ( 9 . 69 . 129 . 189 ) a rolling body raceway ( 25 . 27 . 85 . 87 . 145 . 147 . 205 . 207 ) for guiding the rolling bodies ( 21 . 81 . 101 . 161 ). Bearing arrangement ( 3 . 63 . 123 . 183 ) according to claim 1, characterized in that the shaft ( 9 . 69 . 129 . 189 ) at least in the region of the rolling body track ( 25 . 27 . 85 . 87 . 145 . 147 . 205 . 207 ) consists of a steel. Bearing arrangement ( 3 . 63 . 123 . 183 ) according to claim 1 or 2, characterized in that the shaft ( 9 . 69 . 129 . 189 ) of a number of axially adjacent shaft sections ( 171 . 173 . 175 . 237 . 239 . 241 ) is composed. Bearing arrangement ( 3 . 63 . 123 . 183 ) according to claim 3, characterized in that the shaft sections ( 171 . 173 . 175 . 237 . 239 . 241 ) are welded together. Bearing arrangement ( 3 . 63 . 123 . 183 ) according to one of the preceding claims, characterized in that the shaft ( 9 . 69 . 129 . 189 ) an inner recess ( 29 . 176 . 177 . 178 . 179 ). Bearing arrangement ( 3 . 63 . 123 . 183 ) according to one of the preceding claims, characterized in that the shaft ( 9 . 69 . 129 . 189 ) end face a shaft journal ( 113 . 243 . 245 . 255 ) for attachment to a turbine wheel ( 7 . 67 . 127 . 187 ) having. Bearing arrangement ( 3 . 63 . 123 . 183 ) according to one of the preceding claims, characterized in that the outer bearing ring ( 15 . 17 . 75 . 77 . 135 . 137 . 195 . 197 ) a spray oil well ( 45 . 46 . 105 . 106 . 165 . 166 . 225 . 226 ) for lubricating the rolling bearing ( 13 . 73 . 133 . 193 ). Bearing arrangement ( 3 . 63 . 123 . 183 ) according to one of the preceding claims, characterized in that the shaft ( 9 . 69 . 129 . 189 ) on its outer circumference a number of grooves ( 35 . 95 . 155 . 215 ) for positioning of sealing elements ( 37 . 97 . 157 . 217 ). Bearing arrangement ( 3 . 63 . 123 . 183 ) according to one of the preceding claims, characterized in that the shaft ( 9 . 69 . 129 . 189 ) an oil separator ( 49 . 109 . 169 . 229 ). Turbocharger ( 1 . 61 . 121 . 181 ), comprising a compressor wheel ( 5 . 65 . 125 . 185 ), a turbine wheel ( 7 . 67 . 127 . 187 ), as well as a bearing arrangement ( 3 . 63 . 123 . 183 ) according to one of claims 1 to 7, wherein the compressor ( 5 . 65 . 125 . 185 ) and the turbine wheel ( 7 . 67 . 127 . 187 ) over the wave ( 9 . 69 . 129 . 189 ) and wherein the shaft ( 9 . 69 . 129 . 189 ) with the turbine wheel ( 7 . 67 . 127 . 187 ) is welded.

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