Turbocharger for a motor vehicle with mechanical decoupling

Abstract

The invention relates to a turbocharger for a motor vehicle with mechanical decoupling, comprising a bearing bush, wherein the bearing bush defines a receiving space with an inner wall. The turbocharger comprises a bearing, wherein the bearing is arranged in the receiving space. The turbocharger comprises a damper element, wherein the damper element is arranged between the inner wall of the bearing bush and the bearing for supporting the bearing on the inner wall of the bearing bush in the receiving space, wherein the damper element comprises a wire mesh or is formed by a wire mesh.

Description

The present invention relates to a turbocharger for a motor vehicle with mechanical decoupling.The challenge in existing turbocharger technology is to manage the oscillations generated by operation of a turbocharger. These vibrations may have a negative effect on bearings of the turbocharger, which not only causes noise, but also leads to increased wear and shortens the service life of the bearing. Traditional solutions have proven either too cumbersome or technically not sufficient to effectively dampen the complex vibration patterns generated during operation of the turbocharger.Further developments in turbocharger technology play a decisive role for the driving quality of motor vehicles. The reduction of vibration-induced stress by innovative bearing decoupling not only contributes to the longevity of the turbocharger, but also has a direct influence on the vehicle acoustics and the vibration behavior of the engine. Low vibration operating conditions provide harmonic power deployment and reduce annoying noise in the passenger compartment, which significantly contributes to the general perception of ride comfort and luxus.EP 3 990 787 B1 discloses a compressor of a building air conditioning system. A shaft of the compressor is mounted with a foil bearing which comprises a wire mesh damper.DE 10 2020 134 311 A1 discloses a turbocharger whose rolling bearing is damped and supported in the axial direction by a wire mesh ring.EP 3 990 787 B1 discloses a compressor with a low-play angular contact ball bearing.DE 10 2020 134 311 A1 discloses a turbocharger with an axial damper and displacement limitation.DE 10 2016 212 552 A1 discloses an electric motor-driven air wheel compressor with vibration-damped and compact mounting.DE 10 2014 200 743 A1 discloses an exhaust gas turbocharger with damping rings made of metal fabric.US 2015 / 0267740 A1 discloses a turbocharger having a journal bearing designed as a semi-floating ring with hydrodynamic fluid film solid body joint tilting segments and flexible dampers.The present patent application aims to improve both the concept and the practical implementation of this innovative vibration protection mechanism for turbocharger bearings compared to the prior art and thus to provide the basis for further developments in this area of high technological relevance.For this purpose, according to the invention, a turbocharger for a motor vehicle with mechanical decoupling according to claim 1 is provided. Advantageous embodiments can be taken from the dependent claims and the description.The invention relates to a turbocharger for a motor vehicle with mechanical decoupling, comprising a bearing bush, wherein the bearing bush delimits a receiving space with an inner wall, a bearing of the turbocharger, wherein the bearing is arranged in the receiving space, a damper element of the turbocharger, wherein the damper element is arranged between the inner wall of the bearing bush and the bearing for bearing the bearing on the inner wall of the bearing bush in the receiving space, wherein the damper element comprises a wire mesh or is formed by a wire mesh.The receiving space can be bounded radially by the inner wall. The receiving space has a cylindrical volume, in particular round. The cross section through the receiving space can be round.In an advantageous development, the receiving space comprises a rear wall with a passage for a shaft, i.e. viewed from the front, i.e. viewed in plan view. The receiving space comprises a first end region and a second end region, wherein the first end region is arranged opposite the second end region. The second end region comprises the rear wall with the passage for the shaft. The first end region comprises an opening via which the receiving space is accessible. The damper element can be inserted into the receiving space via the opening. On the first end region, holding means for fastening the damper element or for closing the opening and thus the receiving space can be arranged.In an advantageous development, the bearing is designed as a ball bearing, rolling bearing, angular contact ball bearing or needle bearing. In a further advantageous refinement, the angular contact ball bearing can be prestressed.Angular contact ball bearings are special types of roller and ball bearings, respectively, which can accommodate axial and radial loads in a specific direction. They are designed so that the raceways in the inner and outer rings are arranged at a certain angle to each other, giving them the ability to absorb both radial loads and axial loads acting in one direction.The oblique position of the raceways has the effect that an axial load component can be produced and absorbed when the angular contact ball bearing is radially loaded. This can be used in some applications to compensate for axial forces or to generate a prestress in the angular contact ball bearing arrangement in order to improve the play and thus the accuracy and stability of the bearing.Angular contact ball bearings must be prestressed for various technical reasons in order to ensure optimum functioning. The preload is a method in which a constant load can be applied to the angular contact ball bearing before it is subjected to an operating load. This may be particularly important, particularly in precision applications such as those found in the automotive industry.On the one hand, the prestress prevents too much play from arising in the angular contact ball bearing. Play, i.e. the free movability between the bearing components of the angular contact ball bearing, can lead to undesired vibrations, noises and an inaccurate running. Particularly in applications in which a high accuracy is required, a low-play bearing behavior of the angular contact ball bearing is essential.On the other hand, the prestress of the angular contact ball bearing increases the rigidity of the entire bearing system. A more rigid angular contact ball bearing can absorb higher loads, reacts less to external forces and has a more stable behavior. This is especially important in applications where the angular contact ball bearing is subjected to high loads or impact forces.As a result of the targeted prestress of the angular contact ball bearing, the balls within the angular contact ball bearing are pressed more uniformly between the raceways of the inner ring and outer ring of the angular contact ball bearing, which optimizes the load distribution and thus ensures more uniform wear. This makes it possible to extend the life of the angular contact ball bearing.Furthermore, the prestress helps to minimize the formation of micromovements between the rolling elements and the raceways. These micromovements can lead to a more rapid fatigue and thus to an early failure of the angular contact ball bearing in angular contact ball bearings that are exposed to high rotational speeds.The wire mesh can be configured as an annular wire mesh. The production of an annular wire mesh may require the use of special industrial machines designed for the knitting of wire.In a first step, the wire material is selected which satisfies the requirements of strength, flexibility and corrosion resistance for its use. The wire can then be unrolled from a spool and fed into the knitting machine. The machine can knit in a continuous, round motion to produce a long tubular wire mesh. This knit is then cut and formed into rings, and the ends can be joined into a closed circuit by welding, brazing or other joining technique. Finally, the ring-shaped wire mesh can undergo various post-treatments in order to achieve the desired material properties.In a further advantageous development, a radially extending oil inlet channel is provided in the inner wall of the receiving space, wherein the oil inlet channel can be opened completely or at least partially in the direction of the damper element in order thereby to supply the damper element and / or the bearing with oil. Radial means that, looking into the receiving space, the oil inlet channel extends in the inner wall of the receiving space and completely or at least partially around the receiving space. The oil feed passage may extend at an angle of up to 90 degrees or up to 180 degrees or up to 270 degrees or up to 360 degrees radially in and around the inner wall.In an advantageous refinement, the angular contact ball bearing can be prestressed by oil pressure. The oil pressure may be supplied via the oil supply passage. This method can also be referred to as hydraulic or hydrodynamic prestressing. It may use a force of pressurized oil to apply a uniform and adjustable preload to the angular contact ball bearing. The advantage of this technique lies in particular in its flexibility and precision, since it can be made possible to dynamically and accurately control a prestressing force on the angular contact ball bearing, which can be advantageous in the case of changes in the operating conditions.For example, when the angular contact ball bearing is heated by frictional heat during operation, the prestress can be adjusted in order to ensure a constantly high accuracy and bearing performance. In addition, the hydraulic prestress of the angular contact ball bearing via the oil pressure offers the advantage of effective heat dissipation. The oil itself can function as a cooling medium for the angular contact ball bearing. The prestress of the angular contact ball bearing can also be carried out when the engine is stationary, in particular during the starting process. In particular, a prestress of the angular contact ball bearing can be carried out during a cold start of the motor vehicle. As a result, a high bearing stress or bearing damage of the bearing as a result of lack of lubrication can be prevented in the first one to two seconds of the starting operation. This may be important for cold starting, in particular in cold conditions, if the oil is still viscous.The damper element can be formed in one part or in multiple parts. The damper element can be cylindrical. Wherein the cylinder comprises a first end portion and a second end portion. wherein the first end region is opposite the second end region.In a further development according to the invention, the damper element comprises an outer encapsulation and an inner encapsulation, wherein the wire mesh is arranged between the outer encapsulation and the inner encapsulation.In an advantageous development, the outer encapsulation comprises holes on its circumference spaced apart oil inflow and the inner encapsulation comprises holes on its circumference spaced apart oil outflow. The oil inflow holes are arranged axially centrally in the outer encapsulation, i.e. arranged between the first end region and the second end region. The oil outlet holes are arranged axially on the edge of the inner encapsulation. In this case, a first row of oil outlet holes can be arranged closer to the first end region than to the second end region and / or a second row of oil outlet holes can be arranged closer to the second end region than to the first end region.The oil inlet holes pass radially through the outer encapsulation. The oil outlet holes pass radially through the inner encapsulation. The oil outlet holes and / or the oil inlet holes can be configured as a bore or as an elongated hole in the outer encapsulation of the damper element and / or in the inner encapsulation of the damper element.The bearing can comprise two lubrication grooves running radially around the bearing, through which oil can be guided around the bearing. The oil outlet holes of the damper element can overlap with the two lubrication grooves running around the bearing. As a result, the lubrication grooves can be supplied with oil via the damper element. The ball bearing may comprise additional bores for supplying the ball bearing with oil. Alternatively or additionally, the oil can penetrate into the ball bearing via lateral bearing caps on the ball bearing.The bearing can thereby be lubricated and printed with oil and thereby prestressed. The oil from the oil drain holes of the damper element can be discharged after it has supplied the bearing with oil via an oil drain channel in the bearing bush of the turbocharger. As a result, oil can be passed through the receiving space of the bearing bush. The oil throughput through the receiving space can be 0.5 liter / minute-2 liters / minute.In a further advantageous development, the oil inlet holes are completely or at least partially covered by the radially extending oil inlet channel. In other words, the oil inlet channel lies completely or partially above the oil inlet holes. This means that oil can be supplied to the oil inlet via the radially extending oil inlet channel to holes of the damper element. As a result, oil can be forced through the damper element via the oil inflow channel. The wire mesh can be designed as a filter for filtering the oil.As a result, a sufficient, in particular constant oil throughput can be realized by the damper element in order to supply the bearing with oil.In a further development according to the invention, the outer encapsulation and the inner encapsulation are fluidically sealed with respect to one another. The sealing can be effected via at least two O-rings between the inner encapsulation and outer encapsulation with respect to an outer space. Exterior space means relative to the environment. Fluidically sealed means being sealed with respect to an escape of oil into the outer space. Oil creep may still be possible and is considered to be dense. Between the outer encapsulation and the inner encapsulation, a gap can remain which can be closed by the at least two O-rings. The first O-ring can be located at the first end region between the outer encapsulation and the inner encapsulation, and the second O-ring can be located at the second end region between the outer encapsulation and the inner encapsulation. The gap can mechanically decouple the outer encapsulation of the damper element from the inner encapsulation of the damper element, since there is no direct contact between the outer encapsulation and the inner encapsulation. The outer encapsulation is thus mounted with respect to the inner encapsulation via the at least two O-rings and the wire mesh.In an advantageous development, the wire mesh comprises steel wire or consists of steel wire.In a further advantageous development, the bearing is axially mounted in the receiving space via a spring pack. The receiving space can be closed by an end cap. The spring pack can be arranged on the side of the receiving space arranged on the end cap, that is to say on the rear wall. The spring pack can be circular with a free inner diameter. The free inner diameter can be used for the passage of a shaft through the spring packet.In an advantageous development, the wire mesh has a mesh width of 10 μm up to 100 μm. By adjusting the mesh width, the filtering effect of the wire mesh can be varied.The invention is described below purely by way of example with reference to the drawings. The following are shown: FIG. 1 shows a turbocharger for a motor vehicle with mechanical decoupling; and FIG. 2 shows a damper element for a turbocharger for a motor vehicle with mechanical decoupling; and FIG. 3 shows a turbocharger for a motor vehicle with mechanical decoupling.FIG. 1 shows a turbocharger 100 for a motor vehicle with mechanical decoupling. The turbocharger 100 comprises a bearing bush 110, wherein the bearing bush 110 delimits a receiving space 112 with an inner wall 111. A bearing 120 of the turbocharger 100, wherein the bearing 120 is disposed in the accommodation space 112. A damper element 130 of the turbocharger 100, wherein the damper element 130 is arranged between the inner wall 111 of the bearing bush 110 and the bearing 120 for supporting the bearing 120 on the inner wall 111 of the bearing bush 110 in the receiving space 112. The damper element 130 comprises a wire mesh 131 or is formed by a wire mesh 131. A spring assembly 140 is additionally arranged in the bearing bush, whereby the bearing 120 is prestressed. The oil guidance into and out of the damper element 130 is realized via an oil inflow channel 113 or an oil outflow channel 114.In addition to the oil inlet channel 113, the bearing bush comprises an oil outlet channel 114, via which an oil can be discharged. The bearing 120 comprises two lubrication grooves 121 running radially around the bearing 120, through which oil can be guided around the bearing 120. The bearing 120 can thereby be supplied with oil.The damper element 130 comprises an outer encapsulation 132 and an inner encapsulation 133, wherein a wire mesh 131 is arranged between the outer encapsulation 132 and the inner encapsulation 133. The outer encapsulation 132 comprises oil inlet holes 134 at its circumference spaced apart from one another and the inner encapsulation 133 comprises oil outlet holes 135 at its circumference spaced apart from one another, wherein the oil inlet holes 134 are arranged axially centrally in the outer encapsulation 132 and wherein the oil outlet holes 135 are arranged axially at the edge of the inner encapsulation 133.The outer encapsulation 132 and the inner encapsulation 133 are fluidically sealed with respect to one another. The sealing is effected via at least two O-rings 136 between the inner encapsulation 133 and the outer encapsulation 132 with respect to an outer space.FIG. 2 shows a damper element 130. The damper element 130 comprises an outer encapsulation 132 and an inner encapsulation 133, wherein a wire mesh 131 is arranged between the outer encapsulation 132 and the inner encapsulation 133. The outer encapsulation 132 comprises oil inlet holes 134 at its circumference spaced apart from one another and the inner encapsulation 133 comprises oil outlet holes 135 at its circumference spaced apart from one another, wherein the oil inlet holes 134 are arranged axially centrally in the outer encapsulation 132 and wherein the oil outlet holes 135 are arranged axially at the edge of the inner encapsulation 133.The outer encapsulation 132 and the inner encapsulation 133 are fluidically sealed with respect to one another. The sealing is effected via at least two O-rings 136 between the inner encapsulation 133 and the outer encapsulation 132 with respect to an outer space.A gap can remain between outer encapsulation 132 and inner encapsulation 133, but this gap is closed by the at least two O-rings 136. The gap mechanically decouples the outer encapsulation 132 from the inner encapsulation 133, since there is no direct contact between the outer encapsulation 132 and the inner encapsulation 133.FIG. 3 shows a turbocharger 100 for a motor vehicle with mechanical decoupling. The turbocharger 100 comprises two damper elements 130, which are inserted into two bearing bushes 110 of the turbocharger 100.The invention is not limited to the described exemplary embodiments. Within the scope of the invention, all features described and / or shown can be combined with one another as desired, unless stated otherwise.Reference numerals denote reference numerals100 Turbocharger 110 Bearing bush 111 Inner wall 112 Receiving space 113 Oil inflow channel 114 Oil outflow channel 120 Bearing 121 Lubrication groove 130 Damper element 131 Wire mesh 132 Outer encapsulation 133 Inner encapsulation 134 Oil inflow holes 135 Oil outflow holes 136 O-ring 140 Spring assembly

Claims

Turbocharger (100) for a motor vehicle with mechanical decoupling, comprising a bearing bush (110), wherein the bearing bush (110) delimits a receiving space (112) with an inner wall (111), a bearing (120) of the turbocharger (100), wherein the bearing (120) is arranged in the receiving space (112), a damper element (130) of the turbocharger (100), wherein the damper element (130) is arranged between the inner wall (111) of the bearing bush (110) and the bearing (120) for bearing the bearing (120) on the inner wall (111) of the bearing bush (110) in the receiving space (112), wherein the damper element (130) comprises a wire mesh (131) or is formed by a wire mesh (131), characterized in that the damper element (130) comprises an outer encapsulation (132) and an inner encapsulation (133), wherein the wire mesh (131) is arranged between the outer encapsulation (132) and the inner encapsulation (133), wherein the outer encapsulation (132) and the inner encapsulation (133) are fluidically sealed with respect to one another.Turbocharger (100) for a motor vehicle with mechanical decoupling according to Claim 1, characterized in that the bearing (120) is designed as a ball bearing, rolling bearing, angular contact ball bearing or needle bearing.Turbocharger (100) for a motor vehicle with mechanical decoupling according to one of the preceding claims, characterized in that a radially extending oil channel (113) is provided in the inner wall (111) of the receiving space (112), wherein the oil channel (113) is at least partially open in the direction of the damper element (130), in order thereby to supply the damper element (130) and / or the bearing (120) with oil.Turbocharger (100) for a motor vehicle with mechanical decoupling according to one of the preceding claims, characterized in that the outer encapsulation (132) comprises holes (134) at its circumference spaced apart from one another and the inner encapsulation (133) comprises holes (135) at its circumference spaced apart from one another, wherein the oil inflow holes (134) are arranged axially centrally in the outer encapsulation (132) and wherein the oil outflow holes (135) are arranged axially at the edge of the inner encapsulation (133).Turbocharger (100) for a motor vehicle with mechanical decoupling according to Claim 4, characterized in that the oil inflow holes (134) are completely or at least partially covered by the radially running oil duct (113).The turbocharger (100) for a mechanical decoupling motor vehicle according to any one of the preceding claims, characterized in that the wire mesh (131) comprises steel wire or consists of steel wire.Turbocharger (100) for a motor vehicle with mechanical decoupling according to one of the preceding claims, characterized in that the bearing (120) is mounted axially in the receiving space (112) via a spring pack (140).Turbocharger (100) for a motor vehicle with mechanical decoupling according to one of the preceding claims, characterized in that the wire mesh (131) has a mesh width of 10 μm up to 100 μm.

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