EP3017146B1 - Rotor for a turbocharger device, turbocharger device having a rotor, and shaft for a rotor of said type - Google Patents

Description

The invention is in the field of mechanics, especially of mechanical engineering and can be used with particular advantage in turbocharger devices.

In internal combustion engines in the form of piston engines, turbocharger devices are used to assist the air intake of the pistons by providing an overpressure of the incoming air. For this purpose, a turbocharger usually has a turbine which is driven in the exhaust gas flow by hot air and which is fixedly mounted on a common shaft with a compressor wheel, which in turn causes an increase in pressure of the inflowing air in the supply air duct of the internal combustion engine. The shaft that connects the turbine to the compressor wheel requires considerable torque to be transmitted at very high speeds (several 10,000 - 100,000 revolutions per minute). Challenges in mechanical design include stability against high temperatures in the exhaust stream and shaft bearing for very high speeds. In connection with this, there are also additional problems in the design of the oil lubrication of the bearings, which are usually designed as plain bearings, partly with floating bushings. Accordingly, bearing elements for the radial bearing and the axial bearing as well as sealing elements for the sealing of the oil chamber in the housing of the turbocharger device must be reliably and stably arranged on the shaft.

A known construction in this context builds on a axial bearing element, a sealing sleeve member and a compressor (impeller) axially successively postponed by a first end of the shaft and then by means of a central threaded nut, which on an external thread the shaft is screwed so tightly clamped together in the axial direction that no loosening of the individual parts with respect to the shaft is to be feared even with the mechanical loads during operation and rotate them with the shaft.

An additional measure to ensure the cohesion of said arrangements may be that a certain elasticity and / or an elastic element is provided to compensate for a possible setting behavior of the parts. For this purpose, for example, the shaft shaft could be designed as an "expansion screw". Another arrangement is from the patent DE-102008056059 known. The present invention is based on the background of the prior art the object to provide a rotor for a turbocharger device, in which a permanent and reliable cohesion of the individual parts is ensured in a technically simple and cost-effective manner.

The object is achieved with the features of the invention according to claim 1 with respect to a rotor for a turbocharger device. The dependent claims represent advantageous embodiments of the invention. In addition, a turbocharger device with a rotor according to the invention according to claim 8 is accomplished by the invention. Specifically, the invention relates to a rotor for a turbocharger having a shaft and a paddle wheel, a sealing sleeve member and a rotating with the shaft thrust bearing element, which are axially arranged and fixed on the shaft one behind the other, wherein the sealing sleeve member and the rotating thrust bearing element by means of a at least one of these elements provided internal thread with a shaft arranged on the first Au screwed and screwed against a shaft shoulder and wherein the paddle wheel is axially braced by means of a, axially screwed from the end of the shaft forth, screwed onto a second external thread of the shaft nut, against the sealing sleeve member, the thrust bearing element and the shaft shoulder.

At least one of these parts is fixedly connected to the shaft and fixed and possibly clamped the other part between the screwed part and a shaft shoulder by a threaded bushing with the shaft associated with the sealing sleeve element and / or the axial bearing element rotating with the shaft. The paddle wheel, which typically can be designed as a compressor wheel, can additionally be fixed by its own fixation, for example a further screw connection on the shaft at its first end. It is possible in this way to fix the individual parts on the shaft stronger and more reliable and to ensure the cohesion of the remaining parts even when solving a single part. The elastic forces that can be generated are greater than in the fixation of all items by means of a single screw on the shaft end. As a result, on the one hand, the reliability of the cohesion is increased, on the other hand, the transmission of a higher torque allows, as the parts placed on the shaft parts on their cohesion, the torque that is transmitted across the runner in total, in addition to increase.

By screwing the impeller against the sealing sleeve member and optionally the thrust bearing element with an axial pressing force, a stiction is generated in addition to the fixation of the impeller, which also for additional transmission of torques on said, pushed onto the shaft parts in addition to the torque transmitted by the shaft body itself can serve. In addition, the axial compression of the pushed parts increases the stiffness of the rotor beyond the rigidity of the shaft body. Usual as a one-sided screwing element is a screwed externally on the shaft shaft threaded nut, but it is also conceivable to introduce into a blind bore of the shaft, an internal thread into which a closure body is screwed, which extends outwardly beyond the diameter of the shaft, where the shaft surrounds and on the Paddle wheel applies an axial force.

When applying the various threaded parts onto the shaft, it is expedient to screw one after the other, beginning with the axial bearing element usually arranged next to the shaft shoulder, subsequently the sealing bush element and finally the paddle wheel.

It can be advantageously provided that the sealing bush element has an internal thread which is screwed to a first external thread of the shaft and that the axial bearing element rotating with the shaft is arranged axially between the sealing bush element and the shaft shoulder.

In this case, the axial bearing element, which for example essentially has an annular axial bearing disk, can be freely displaceable on the shaft. The thrust bearing element is fixed in this case only by the fit on the shaft in the radial direction and by the clamping action of the sealing sleeve member axially on the shaft.

It can also advantageously be additionally or alternatively provided that the axial bearing element has an internal thread which is screwed to an external thread of the shaft.

In this case, the thrust bearing element is additionally bolted to an external thread of the shaft and pressed against a shaft shoulder.

In this way, the axial pressing pressure can be added by the individual screwings of the sealing sleeve member and thrust bearing element.

It may also be advantageously provided that the axial bearing element or an axial section of the axial bearing element is formed integrally with the sealing bushing element.

In this case, the number of slid on the shaft items can be reduced and their cohesion can be further improved. Thus, the transmittable by the rotor torque is increased and increases the stiffness of the rotor as a whole. The additionally transmissible torque is then determined by the friction between the impeller and the seal bushing element on the one hand and the friction between the thrust bearing element and the shaft shoulder on the other hand.

In particular, by increasing the rotor stiffness due to a stable cohesion of the deferred parts logically also the vibration behavior of the rotor and the shaft is improved, which is very advantageous at the high speeds of a turbocharger in operation and even with the expected changes in rotational speeds corresponding to different load conditions of the engine is. The release of individual parts of the rotor by vibrations is also unlikely in this way.

The invention can also be advantageously configured in that the second external thread of the shaft and the first external thread of the shaft have opposing slopes.

In this case, it is ensured that a torque applied to the paddle wheel, which may for example consist in the drag in operation, which is opposed to a rotation of the paddle wheel, rotates the paddle wheel relative to the shaft, and it is also prevented the impeller adjacent element, so typically the seal bushing element is rotated by the static friction forces in the same direction.

This results in an additional stabilization of the runner cohesion against unwanted twists, which could result in an unwanted loosening of the items.

It can also be advantageously provided that the second external thread of the shaft and the first external thread of the shaft in the same direction inclines with different pitch angles, wherein the first external thread is formed steeper than the second external thread.

In such an embodiment of the external thread is also when one of the parts is rotated, co-rotation of the static friction partner, so for example in primary rotation of the impeller, the co-rotation of the Dichtungsbuchselements prevented since the different pitches of the thread would cause an amplification of the pressing together of the parts, which is prevented by the already produced from the beginning during assembly pressing pressure.

The invention relates not only to a rotor, as has already been described above, to a turbocharger device with such a rotor and with a housing, wherein on the housing according to the invention, a housing-fixed thrust washer is arranged, the ring-segment-shaped, to one side open for assembly and interspersed by the shaft.

Since the shaft usually preassembled as a whole, that is also connected to the deferred parts, such as rotating with the shaft thrust bearing element, a sealing sleeve member and an impeller, is connected to the housing, the rotor is usually from one side transverse to the longitudinal direction of the shaft in to insert the housing. This is the shaft can not be pushed through annular housing-fixed bearing elements and must either be pre-assembled with all annular bearing elements or inserted into the housing-fixed bearing elements from the side. This is possible with respect to a thrust washer in that the housing-fixed thrust washer represents not a complete ring but only a ring segment with an opening into which the shaft can be inserted with the rotating with the shaft thrust bearing element. Another part of the housing-fixed thrust washer can be added and screwed after assembly of the shaft to complete the thrust bearing.

In addition to a rotor of the above type and a turbocharger device, the present invention also relates to a shaft for a rotor of the type described above, wherein the shaft between a first shaft end and a shaft shoulder on which the shaft, seen from the first shaft end , whose diameter increases abruptly, having a first external thread, and in that the shaft in addition to the first external thread has a further thread, in particular a second external thread, which is spatially separated from the first external thread.

The provision of two separate threads or, in other words, two spatially separated axial sections which are each provided with a thread, allows the separate fixing and axial pressurization or pressing of a paddle wheel on the one hand and a pushed onto the shaft sealing bushing element and / or with a the shaft rotating thrust bearing element on the other. As a result, a relaxation of individual of these parts against the shaft is more reliably prevented than if all parts were pressed together by a single screw and against a shaft shoulder. It can also be applied higher overall axial forces than a single screw.

In the following the invention will be shown with reference to an embodiment in the figures and explained below.

• Fig. 1 einen Längsschnitt durch einen Läufer einer Turboladereinrichtung gemäß dem Stand der Technik mit einem Teil eines Gehäuses,
• Fig. 2 eine ausschnittsweise Vergrößerung aus der Fig. 1,
• Fig. 3 einen Längsschnitt eines Läufers einer Turboladereinrichtung gemäß der Erfindung mit einem Teil eines Gehäuses,
• Fig. 4 eine Ausschnittsvergrößerung aus der Fig. 3,
• Fign. 5 bis 8 verschiedene Ansichten einer Kombinationsbuchse, die ein Dichtungsbuchsenelement und ein mit der Welle rotierendes Axiallagerelement zusammenfasst,
• Fig. 9 eine Darstellung eines Läufers teilweise in einer Seitenansicht, teilweise im Längsschnitt mit einem Verdichterrad und einer auf die Welle aufgeschobenen Kombinationsbuchse,
• Fig. 10 die Darstellung aus Fig. 9, wobei das Verdichterrad und die Kombinationsbuchse weggelassen sind,
• Fig. 11 eine Darstellung einer gehäusefesten Axiallagerscheibe,
• Fig. 12 eine Detaildarstellung einer Welle mit einer aufgeschraubten Kombinationsbuchse,
• Fig. 13 eine Detaildarstellung einer Welle mit auf diese aufgeschobenen Teilen des mit der Welle rotierenden Axiallagerelementes sowie einem aufgeschraubten Dichtungsbuchsenelement,
• Fig. 14 im Detail zwei Teile eines mit der Welle rotierenden Axiallagerelements sowie ein Dichtungsbuchsenelement im Längsschnitt,
• Fig. 15 in einer Seitenansicht einen zu den in Fig. 14 dargestellten Teilen passenden Läufer mit einer teilweise unbestückten Welle,
• Fig. 16 einen Läufer, der mit den in Fig. 14 dargestellten Teilen sowie einem Verdichterrad bestückt ist,
• Fig. 17 eine Detaildarstellung einer Kombinationsbuchse auf einer Welle im Längsschnitt sowie
• Fig. 18 eine weitere Detaildarstellung einer anderen Ausführungsform einer Kombinationsbuchse auf einer Welle im Längsschnitt.

It shows

• Fig. 1 a longitudinal section through a rotor of a turbocharger according to the prior art with a part of a housing,
• Fig. 2 a partial enlargement of the Fig. 1 .
• Fig. 3 a longitudinal section of a rotor of a turbocharger according to the invention with a part of a housing,
• Fig. 4 an excerpt from the Fig. 3 .
• FIGS. 5 to 8 various views of a combination bushing, which summarizes a sealing bushing element and a rotating with the shaft thrust bearing element,
• Fig. 9 a representation of a runner partially in a side view, partially in longitudinal section with a compressor wheel and a pushed onto the shaft combination socket,
• Fig. 10 the presentation Fig. 9 with the compressor wheel and the combination socket omitted,
• Fig. 11 a representation of a housing-fixed thrust bearing,
• Fig. 12 a detailed representation of a shaft with a screwed combination socket,
• Fig. 13 a detailed representation of a shaft with pushed onto these parts of the rotating shaft with the thrust bearing element and a screwed-sealing sleeve element,
• Fig. 14 in detail, two parts of a rotating with the shaft thrust bearing element and a sealing bushing element in longitudinal section,
• Fig. 15 in a side view one to the in Fig. 14 shown parts matching runner with a partially unpopulated shaft,
• Fig. 16 a runner with the in Fig. 14 shown parts and a compressor wheel is equipped,
• Fig. 17 a detailed view of a combination socket on a shaft in longitudinal section and
• Fig. 18 a further detail of another embodiment of a combination socket on a shaft in longitudinal section.

In the Fig. 1 is a part of a turbocharger device 2 according to the prior art in a longitudinal section through the shaft of the rotor and a partial view of housing parts shown. The rotor has on the exhaust side a turbine wheel 18, which is driven by the exhaust gas flow of a combustion piston engine. The turbine wheel 18 is mounted on a common shaft 3 with a paddle wheel / compressor wheel 4 which delivers air in an intake air passage to the intake valves of the internal combustion engine and compresses with the aim of more effective combustion in the piston chambers.

The compressor 4 is mounted on the shaft 3 by means of a threaded nut 13 which is screwed as a centric screwing element on an end-side external thread of the shaft 3 and the compressor 4 pressed together with the interposition of various additional elements against a shaft shoulder.

In the interior of the housing 15 of the turbocharger device 2 also two radial bearings 19, 20 are provided, which for a radial bearing of the shaft 3, even in the typically more ten thousand revolutions per minute to serve a few hundred thousand revolutions per minute amounts of speed. The radial bearings are designed, for example, as floating plain bearings, in which the floating bushings can rotate relative to housing-fixed bearing elements with about half the number of revolutions of the shaft.

Via an oil supply device 21, both the radial bearings and a thrust bearing explained in more detail below are supplied with lubricating oil.

The Fig. 2 shows a part of the Fig. 1 , enlarged in detail, in particular except the compressor 4, the between this and a shaft shoulder 12 jammed annular components are shown, of which a first one Dichtbuchsenelement 5, a second second part 8 of a rotating shaft bearing with the Axiallagerelements and a third a second part 8 'represents a rotating with the shaft thrust bearing element. The three mentioned clamped elements 5, 8, 8 'are freely displaceable in the axial direction on the shaft 3 and are held exclusively by static friction forces between the compressor wheel 4 and the shaft shoulder 12.

In the Fig. 2 In addition, a housing-fixed thrust washer 9 is shown, which projects radially between the first part 8 and the second part 8 'of the rotating thrust bearing element and is arranged axially between them. The housing-fixed thrust washer 9 thus forms a substantially annular or annular sector-shaped disc, on which the two parts 8, 8 'of the rotating with the shaft thrust bearing element and slide out.

The Fig. 3 shows in the context of the invention, a construction in which on a shaft 3 ', which carries a first external thread 11, a combination socket 22 is screwed, which integrally a sealing bushing element and a first and a second part of a rotating with the shaft thrust bearing element united in itself. In this case, only the axial section which corresponds to the sealing bush element is provided with an internal thread which is screwed onto the corresponding first external thread 11 of the shaft. The first and second parts of the thrust bearing member are not internally threaded and slid onto the axial portion of the shaft adjacent the first external thread 11 in an accurate fit.

The combination bush 22 is firmly clamped against a shaft shoulder 12 of the shaft 3 'by the screw. From the first end 23 of the shaft 3 'forth also a compressor 4 is pushed onto the shaft 3' and pressed by a threaded nut 13 relative to the combination socket 22. The threaded nut 13 is screwed onto a second external thread 14 at the first end 23 of the shaft 3 '. The threaded nut 13 has for this purpose a matching outer contour, for example, a hexagonal contour on.

The combination bush 22 may have on at least one of its elements, that is, for example, at the axial portion of the seal bushing element, but advantageously on one of the parts that correspond to the rotating with the shaft thrust bearing element, an octagonal or square contour, the attack of a tool, for example a wrench for screwing allowed.

In the Fig. 4 is the one in the Fig. 3 an overview of a construction shown in more detail in a detail. It is the combination socket 22 shown enlarged with a first axial portion 5 corresponding to a Dichtungsbuchsenelement, a second portion corresponding to the first part 8 of a rotating thrust bearing element and a third portion which corresponds to the second part 8 'of a rotating shaft with the Axiallagerelements , The individual sections are in the Fig. 4 delimited by dashed lines against each other. It is from the Fig. 4 In addition, it can be seen that the second and third axial portion of the combination socket 22, formed by the first Part 8 and the second part 8 'of the thrust bearing element are not provided with an internal thread but with a cylindrical inner surface 24 which is over the first external thread 11 of the shaft 3' axially pushed over. For this purpose, after cutting the thread, the first external thread 11 is over-turned, ie machined such that the outer contour of the external thread 11 corresponds as exactly as possible to the outer contour of the well 3 'in the area of the cylindrical inner surface 24 of the elements 8, 8'. Thus, a precise fit between the unthreaded portion of the combination socket 22 and the shaft and thus a centering and fixing can be achieved, which helps to avoid imbalance of the rotor.

In the Fig. 4 In addition, a part of the housing-fixed thrust bearing 9 are shown and piston rings 16, 17 corresponds to the first axial portion of the combination socket 22 of the sealing sleeve member 5. The sealing sleeve element thus forms with circumferential outer grooves and piston rings guided therein 16, 17 an effective seal of the shaft relative to the housing 15th

The FIGS. 5, 6, 7 and 8 show from different views the combination socket 22, in the Fig. 5 in a front view, in the Fig. 6 in a side view, in the Fig. 7 in a longitudinal section and in the Fig. 8 in a three-dimensional view. Especially in the Fig. 7 the axial sections of the combination bushing 22 can be seen corresponding to the sealing bushing element 5, the first part 8 of the axial bearing element and the second part 8 'of the axial bearing element. It can also be seen that only the sealing bushing element 5 has an internal thread 10.

In addition, it is shown that in the region of the first part 8 of the axial bearing element a polygonal outer contour 25 of the combination bushing 22 is provided.

In the Fig. 9 is a side view and partially longitudinally sectional view of a rotor 1 shown, as he basically already from the FIGS. 3 and 4 is apparent. It is based on the Fig. 9 It can be seen particularly clearly that the contact surface 26 on which the compressor wheel 4 bears against the combination bush 22 is larger than the contact surface which the combination bush 22 has in the contact region 27 with the shaft shoulder 12. It will be clear that a considerable torque can thus be transmitted in the region between the combination bush 22 and the compressor wheel 4. This is particularly advantageous if the torque to be transmitted is not limited by the contact surface 27 between the combination socket 22 and the shaft shoulder 12, because the combination socket 22 in turn has an independent fixation on the shaft 3 '. As a result, a part of the advantages of the invention is realized.

The Fig. 10 shows the runner from the Fig. 9 without the deferred combination socket, the compressor wheel and the fastening nut 13, but with the first external thread 11, which is axially clearly spaced from the second external thread 14.

The Fig. 11 shows in a three-dimensional view of a housing-fixed thrust washer 9, which has a ring-segment-shaped bearing surface 9 '. This is interrupted in an angular range of about 60 ° in order to keep open to this side of the housing fixed thrust washer and to allow lateral insertion of the shaft and the rotating shaft with the thrust bearing element. When inserting the shaft, the first and second part 8 ', 8 "of the rotating with the shaft thrust bearing element on both sides of the housing fixed thrust bearing 9 are positioned.

The FIGS. 13, 14, 15, 16 show in different sections and views, respectively, a configuration of a turbocharger device, in which the sealing sleeve element 5, the first part 8 of an axial bearing element rotating with the shaft and the second part 8 'of the thrust bearing element are formed as three separate components each having a central internal thread. Accordingly, on the shaft 3 '', a first external thread 11 is provided, which is axially formed so long that all three elements 5, 8, 8 'can be screwed onto the shaft shoulder 12 thereon. By means of each one of the elements 5, 8, 8 'can be constructed in this way an axial pressure, so that the individual parts are very well secured against loosening. It is useful in this context, each of the components 5, 8, 8 'to be provided with a peripheral outer contour, which allows the attack of a tool, such as a wrench to tighten each of the elements individually on the thread 11 can. The thread 11 extends almost to the shaft shoulder 12, while still an axial distance between the end of the external thread 11 and the shaft shoulder 12 is provided. The shaft 3 '''has at least three axial sections with different diameters, wherein the area with the largest diameter forms the shaft shoulder 12, a region of lesser outer diameter carries the external thread 11 and relative to the provided with the external thread 11 axial portion of the shaft the axial end region facing the first shaft end 23 is further reduced in diameter, so that the elements 5, 8, 8 'on the shaft can be simply slid over the first shaft end 23 as far as the external thread 11.

In the end region of the shaft 3 '' ', this has the second external thread 14 for screwing on a threaded nut and for fastening a compressor wheel between the threaded nut 13 and the sealing sleeve element 5.

The Fig. 16 shows the mounted runner in a partially executed as a longitudinal section image, while the Fig. 14 in longitudinal sections one above the other, the three elements 5 (sealing bushing element), 8 (first part of the rotating with the shaft thrust bearing element) and 8 '(second part of the rotating shaft with the thrust bearing element).

The FIGS. 17 and 18 each show a construction in which the first part 8 of the rotating with the shaft thrust bearing element with the sealing sleeve member 5 is integrally combined. In both constructions shown, the so-called bearing collar, that is to say the second part 8 'of the axial bearing element, is separated from the first part 8 of the axial bearing element and formed as an independent body. This allows a simplified mounting of the thrust bearing by the shaft can be provided with the second part of the thrust bearing element and then pushed through by a stationary thrust washer. Thus, if necessary, the housing-fixed thrust washer can be formed as a two-part fully annular bearing element. However, it is conceivable in this context, the use of a laterally open thrust washer.

The combined into one piece combination socket, which combines the parts 5 (sealing sleeve member) and 8 (first part of the thrust bearing element) in itself, can be screwed separately on the external thread 11 'of the shaft.

The described embodiments of the invention allow a particularly firm cohesion of the various pushed onto a shaft parts, such as the parts of the rotating shaft with the thrust bearing element, a sealing bushing and a compressor wheel. In addition, the flexural rigidity of the rotor is increased by a particularly firm connection of the applied to the shaft parts and thus reduces the susceptibility to vibration of the shaft and the susceptibility to the formation of imbalances. Ultimately, particularly large torques between a turbine wheel and a compressor wheel can be transmitted by the described arrangements.

Claims (8)

1. Rotor (1) for a turbocharger device (2), having a shaft (3, 3', 3") and having, arranged and fixed axially one behind the other on the shaft (3, 3', 3''), an impeller (4), a seal bushing element (5) and an axial bearing element (8, 8') which rotates with the shaft (3, 3', 3''), wherein the seal bushing element (5) and the axial bearing element (8, 8') are, by way of an internal thread (10, 10', 10'') which is provided on at least one of said elements, screwed together with a first external thread (11, 11') arranged on the shaft (3, 3', 3'') and are braced against a shaft shoulder (12) and characterized in that the impeller (4) is braced axially with respect to the seal bushing element (5), the axial bearing element (8, 8') and the shaft shoulder (12) by way of a threaded nut which is screwed axially from the end (23) of the shaft (3) onto a second external thread (14) of the shaft (3).
2. Rotor according to Claim 1, characterized in that the seal bushing element (5) has an internal thread (10) which is screwed together with a first external thread (11) of the shaft (3), and in that the axial bearing element (8, 8') is arranged axially between the seal bushing element (5) and the shaft shoulder (12).
3. Rotor according to Claim 2, characterized in that the axial bearing element (8, 8') has an internal thread (10', 10") which is screwed together with an external thread (11) of the shaft (3, 3', 3'').
4. Rotor according to Claim 1, 2 or 3, characterized in that the axial bearing element (8, 8'), or an axial sub-section of the axial bearing element, is formed integrally with the seal bushing element (5).
5. Rotor according to one of Claims 1 to 4, characterized in that the second external thread (14) of the shaft (3) and the first external thread (11) of the shaft (3) have counterdirectional thread gradients.
6. Rotor according to one of Claims 1 to 5, characterized in that the second external thread (14) of the shaft (3) and the first external thread (11) of the shaft (3) have codirectional thread gradients with different thread gradient angles, wherein the first external thread is of steeper form than the second external thread.
7. Rotor according to one of Claims 1 to 6, characterized in that the first external thread (13) of the shaft (3) is machined such that its outer diameter is smaller than or equal to the outer diameter of the shaft (3) between the first external thread (11) and the shaft shoulder (12).
8. Turbocharger device having a rotor (1) according to one of Claims 1 to 7 and having a housing (15), characterized in that, on the housing, there is arranged an axial bearing disk (9) which is fixed with respect to the housing and which is of ring segment-shaped form, is open to one side for installation purposes, and is extended through by the shaft.

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