Axial turbine for a turbomachine, associated dismantling method, and use

Abstract

An axial turbine for a turbomachine, a turbomachine, and methods for dismantling a nozzle ring are described herein. The axial turbine for a turbomachine has a turbine housing, a turbine wheel which is arranged in the turbine housing and is mounted on a shaft, and a nozzle ring (110) which is arranged in the turbine housing (160) and at least partially upstream of the turbine wheel. The nozzle ring has an outer ring (112). Furthermore, the axial turbine comprises a cover ring (120) which is arranged in the turbine housing (160) and downstream of the nozzle ring (110), and a fastening means (140) which detachably connects the outer ring (112) to the cover ring (120) radially outwardly in the axial direction. A downstream end portion of the outer ring (112) has a radially outwardly projecting nozzle ring cam (115), and an upstream end portion of the cover ring (120) has a cover ring cam holder (121). The nozzle ring cam (115) engages the cover ring cam holder (121).

Description

AXIAL TURBINE FOR A TURBOMACHINE, ASSOCIATED METHOD FOR DISMANTLING AND USE Technical area

[0001] The present disclosure relates to an axial turbine for a turbomachine, a turbomachine, and a method for disassembling a nozzle ring. background

[0002] Today, exhaust gas turbochargers are standard equipment for increasing the performance of internal combustion engines. They consist of a turbine on the exhaust side of the engine and a compressor upstream of the engine. The exhaust gases from the engine are expanded in the turbine. The resulting power is transferred via a shaft to the compressor, which compresses the air supplied to the engine. By using the energy from the exhaust gases to compress the air supplied to the combustion process in the engine, the performance, combustion process, and efficiency of the engine can be improved.

[0003] Typically, the nozzle ring of a turbocharger axial turbine is The gas inlet housing or gas outlet housing is secured by means of a screw connection. The nozzle ring screw connection can be located on the inside or outside of the nozzle ring.

[0004] Alternatively, the nozzle ring can also be secured by means of a clamp connection, for example, between the gas inlet casing and the gas outlet casing. The cap of the gas inlet casing is usually connected to the outer part of the gas inlet casing by struts. It has been shown that the struts between the cap and the outer part of the gas inlet casing in the flow channel can have a negative impact on turbine efficiency and the vibration behavior of the turbine rotor blades.

[0005] The aforementioned design variants lead to suboptimal designs with regard to efficiency influence and vibration behavior, and cause considerable effort during disassembly and assembly, which ultimately manifests itself in costs and increased time requirements in the case of servicing. Summary of the invention

[0006] The object of the present invention is to provide an axial turbine which is improved with respect to at least one of the disadvantages known from the prior art.

[0007] To solve the above task, an axial turbine for a Turbomachine, and a method for disassembling a nozzle ring according to the independent claims are provided. Further embodiments, modifications, and improvements will become apparent from the following description and the appended claims.

[0008] According to one embodiment, an axial turbine for a turbomachine, in particular for an exhaust gas turbocharger, is provided. The axial turbine comprises a turbine housing, a turbine impeller arranged in the turbine housing and mounted on a shaft; and a nozzle ring arranged in the turbine housing and at least partially upstream of the turbine impeller, wherein the nozzle ring has an outer ring. Furthermore, the axial turbine comprises a cover ring arranged in the turbine housing and downstream of the nozzle ring, and a fastening means which releasably connects the outer ring to the cover ring radially outward in the axial direction. A downstream end portion of the outer ring has a radially outwardly projecting nozzle ring cam, and an upstream end portion of the cover ring has a cover ring cam receptacle. The nozzle ring cam engages in the cover ring cam receptacle.

[0009] The axial direction and the radial direction are determined by the shaft of the Axial turbine defined. A fastening means that connects the outer ring to the cover ring "radially outward" can be understood to mean that the fastening means is arranged in a radially outer region of the outer ring and / or the cover ring, in particular either at a radial end of the outer ring and / or the cover ring or in a radially outer end section of the outer ring and / or the cover ring.

[0010] The term “in the axial direction” is preferably understood to mean that the Fastening means extends substantially in the axial direction.

[0011] A “downstream end section” includes the downstream end as well as a section in the region of the downstream end, and an “upstream end section” includes the upstream end as well as a section in the region of the upstream end.

[0012] In the present disclosure, a "nozzle ring arranged at least partially upstream of the turbine runner" is understood to mean a nozzle ring in which a portion of the nozzle ring may not be arranged upstream of the turbine runner. However, a "nozzle ring arranged at least partially upstream of the turbine runner" can also be understood to mean a nozzle ring arranged entirely upstream of the turbine runner.

[0013] Thus, an axial turbine is advantageously provided which is improved with regard to assembly and disassembly, particularly during servicing. In particular, the embodiments of the axial turbine described herein reduce the time required for assembly and disassembly, which has a positive impact on costs. A further advantage is that the nozzle ring cams and the cover ring cam holder can be manufactured using simple turning and milling operations, so that in the embodiments described herein, the number of manufacturing steps can be advantageously reduced compared to the prior art. Furthermore, the embodiments described herein enable a minimization of screw connections.Furthermore, embodiments described herein advantageously enable the possibility of minimizing possible efficiency losses and reducing the risk of vibration excitation of the blades of the turbine impeller.

[0014] The turbine casing may comprise a gas inlet casing and a Gas outlet housing. The gas inlet housing can be detachably connected to the gas outlet housing by means of a fastening means, for example a screw connection. The turbine impeller, the nozzle ring, the cover ring, and in particular a diffuser, can be arranged within the turbine housing. The shaft can be arranged at least partially within the turbine housing. The cover ring and / or the turbine diffuser are preferably arranged within the gas outlet housing.

[0015] The nozzle ring can be arranged inside the gas outlet housing. Typically, the nozzle ring is located within the gas inlet housing and the gas outlet housing. In addition to attaching the nozzle ring to the cover ring, the nozzle ring can also be secured by means of a clamp connection, for example, through the gas inlet housing, or by means of a clamp connection between the gas inlet housing and the gas outlet housing.

[0016] The nozzle ring typically has a plurality of guide vanes formed within the outer ring. Furthermore, the nozzle ring may have an inner ring. The inner ring may be formed within the guide vanes. The inner ring and the guide vanes are preferably arranged upstream of the turbine wheel. The outer ring, the guide vanes, and the inner ring, and in particular the entire nozzle ring, may be integrally formed. For example, the outer ring, guide vanes and inner ring can be integrally connected to one another or can be made from one workpiece.

[0017] The axial turbine, and in particular the gas inlet casing, may further comprise a Have a spherical cap. The spherical cap can be arranged on an upstream end section of the nozzle ring and / or in the region of the gas inlet housing. Typically, the spherical cap is not fixed to the turbine housing. The spherical cap preferably does not have any struts or the like connected to the turbine housing. The spherical cap is therefore preferably neither materially bonded nor connected to the turbine housing by a screw connection. In a preferred embodiment, the spherical cap is formed integrally with the nozzle ring, in particular the inner ring of the nozzle ring. For example, the inner ring and spherical cap can be materially bonded to one another or can also be manufactured from a single workpiece. In an alternative embodiment, the spherical cap is attached exclusively to an inner ring of the nozzle ring.

[0018] Omitting a connection between the cap and the turbine casing can help reduce potential efficiency losses and the risk of vibration excitation of the turbine runner blades. Furthermore, omitting a material connection between the cap and the turbine casing, for example, by omitting struts, allows access to the "internal" components of the axial turbine from the turbine side, or in other words, access from the "warm" side. This possible access is described in more detail below.

[0019] The cover ring can be installed inside the gas outlet housing and in the area of ​​the Turbine runner. The cover ring can surround at least a portion of the turbine runner. The cover ring can enclose a portion of the turbine runner radially outward and, in the region of the rotor blades, delimit the flow channel radially outward. This can prevent a fluid (e.g., exhaust gas) from bypassing the turbine runner, in particular the rotor blades of the turbine runner of the axial turbine. The cover ring is typically not directly attached to the turbine housing.

[0020] In one embodiment, the axial turbine further comprises a turbine diffuser arranged at least partially downstream of the turbine impeller. The turbine diffuser can be connected to the turbine housing, in particular the gas outlet housing, for example by means of a screw connection.

[0021] In one embodiment, the turbine diffuser is integral with the Cover ring. For example, the cover ring and turbine diffuser can be integrally connected or made from a single workpiece. The turbine diffuser contains the cover ring at the upstream end section and a Diffuser section. This design allows for a simpler construction with fewer connections.

[0022] In an alternative embodiment, the cover ring is detachably connected to the Turbine diffuser connected. Here, a downstream end section of the cover ring is detachably fastened to an upstream end section of the turbine diffuser. Preferably, the axial turbine has one or more (for example 4 or 6) fastening elements which connect the turbine diffuser to the cover ring. The fastening element preferably connects the outer ring to the cover ring radially outward in the axial direction. The at least one fastening element can be spaced apart in the circumferential direction from the fastening means (which detachably connects the outer ring and cover ring) and an optional clamping segment. The axial turbine can be configured to insert and / or loosen and remove the fastening element by means of a turbine-side access (or from the “warm” side). This possible access is described in more detail below. This enables disassembly orallows the cover ring to be removed via a turbine-side access.

[0023] For example, the fastener can be located along a The fastening element can extend into the insertion opening or through-hole of the cover ring. Furthermore, the fastening element can engage a thread in the turbine diffuser. The fastening element can be a pin, in particular a pin with an internal thread, a bolt, in particular a bolt with an internal thread, or a screw.

[0024] In one embodiment, the outer ring has a clamping segment, wherein the fastening means extends through an insertion opening in the clamping segment. Furthermore, the fastening means can engage a thread in the cover ring.

[0025] The outer ring of the nozzle ring has the radially outwardly projecting Nozzle ring cam and optionally the clamping segment. Typically, the outer ring is integrally connected to the clamping segment and the nozzle ring cam.

[0026] The nozzle ring cam can be flat perpendicular to the axial direction. The nozzle ring cam can have the shape of a tab. The axial extension of the nozzle ring cam can be significantly smaller than the radial extension and / or the circumferential extension. The nozzle ring cam can be a radial projection that protrudes from the radial end or the radial end portion of the outer ring.

[0027] The clamping segment can be flat perpendicular to the axial direction. The axial expansion of the clamping segment can be significantly smaller than the radial expansion. Extension and / or an extension in the circumferential direction. The clamping segment can be a radial projection that protrudes from the radial end or the radial end portion of the outer ring.

[0028] The clamping segment can be attached to the downstream end portion of the The clamping segment can be arranged on the outer ring, and in particular protrude radially from the downstream end portion of the outer ring. The clamping segment can be arranged near the nozzle ring cam both in the axial direction and in the circumferential direction. The clamping segment is preferably arranged at a distance upstream from the nozzle ring cam. For example, the clamping segment can be mounted a few millimeters upstream of the nozzle ring cam.

[0029] Additionally or alternatively, the clamping segment can at least partially overlap the nozzle ring cam in the circumferential direction. The clamping segment can have a greater extent in the circumferential direction than the nozzle ring cam. For example, the nozzle ring cam can extend completely within the clamping segment in the circumferential direction.

[0030] In one embodiment, the clamping segment has two insertion openings or through-bores. The axial turbine can further have at least two fastening means with which the outer ring is detachably connected to the cover ring. The cover ring can have at least two threads. Each of the at least two fastening means can extend through one of the insertion openings in the clamping segment. Furthermore, the at least two fastening means can engage in one of the threads in the cover ring. The fastening means can further extend through a guide hole in the cover ring. The thread can be arranged downstream of the guide hole.

[0031] The nozzle ring cam can be seen in the circumferential direction between the two Insertion openings or through-holes of the clamping segment can be arranged. Thus, the at least two insertion openings can each be spaced circumferentially from the nozzle ring cam. For example, one of the two insertion openings can be spaced clockwise in the circumferential direction from the nozzle ring cam, and the other of the two insertion openings can be spaced counterclockwise in the circumferential direction from the nozzle ring cam.

[0032] The upstream end section of the cover ring has the cover ring Cam seat or groove. To attach the nozzle ring to the cover ring, the nozzle ring can be aligned (rotated) so that the nozzle ring cam can be countersunk into the cover ring cam seat. The engagement of the cam in the cam seat creates a tangential contact surface. This allows the nozzle ring to be centered or the position of the The nozzle ring's diameter can be determined in the circumferential direction. Furthermore, the tangential contact surface between the nozzle ring cam and the cover ring cam seat enables more reliable torque transmission. The cam seat can have dimensions corresponding to those of the nozzle ring cam. For example, the cam seat can be slightly larger in the circumferential direction than the cam. This type of torque transmission between the cam and cam seat allows for radial expansion of the nozzle ring during operation, thereby improving the thermo-mechanical fatigue behavior.

[0033] According to an embodiment, with other methods described herein The cam receptacle has radially extending, opposing, and circumferentially spaced-apart side walls for circumferentially securing the nozzle ring cam of the nozzle ring. Typically, the circumferential distance between the two side walls is selected such that there is no play between the nozzle ring cam and the cam receptacle.

[0034] According to one embodiment, the cover ring has a clamping projection for receiving the clamping segment. The clamping projection can have one or more flat receiving sections on which the clamping segment can be supported or against which the clamping segment can be pressed. The clamping projection can have at least one thread in the cover ring. The cover ring cam receptacle can be arranged between the clamping projection, viewed in the circumferential direction. Additionally or alternatively, the cover ring cam receptacle can be arranged axially downstream of the clamping projection. The clamping projection can have two receiving sections. For example, one receiving section can be arranged at a clockwise distance from the cam receptacle, viewed in the circumferential direction, and the other receiving section can be arranged at a counterclockwise distance from the cam receptacle, viewed in the circumferential direction.

[0035] The fastening device enables, preferably together with the Clamping segment (and possibly the clamping projection), an axial fixation between the nozzle ring and cover ring. The fastening means enable the clamping segment to be pressed against the cover ring (optionally against the clamping projection), and the clamping segment can press the cam into the cam receptacle. In other words, axial fastening of the outer ring to the cover ring by means of the at least one fastening means enables the nozzle ring cam to be pressed into the cover ring cam receptacle. In particular, it also enables the clamping segment to be pressed against the clamping projection. The combination of cam and cam receptacle on the one hand and fastening means and clamping segment on the other hand enable simultaneous centering and axial fastening of the nozzle ring.

[0036] According to an embodiment, with other methods described herein The fastening means has an internal thread, which can be combined with other embodiments. A fastening means with an internal thread is advantageous for removing the fastening means during disassembly using a tool with a corresponding external thread. The fastening means can be a pin, in particular a pin with an internal thread, a bolt, in particular a bolt with an internal thread, or a screw.

[0037] Pressing the clamping segment against the cover ring using the The fastener can also lead to contact between the clamping segment and the nozzle ring cam. The pressure can cause the nozzle ring cam to push the clamping segment axially upstream or to protrude axially into the clamping segment. The clamping segment can be bent by the nozzle ring cam and exert a resilient axial clamping force on the nozzle ring cam.

[0038] In one embodiment, the axial turbine is configured such that, by axially fastening the outer ring to the cover ring by means of the fastening means, the nozzle ring cam moves at least a portion of the clamping segment upstream in the axial direction by at least 0.05 mm, preferably at least 0.1 mm, more preferably at least 0.2 mm, and most preferably at least 0.3 mm. Alternatively or additionally, the axial turbine can be configured such that, by axially fastening the outer ring to the cover ring by means of the fastening means, the nozzle ring cam protrudes into the clamping segment by at least 0.05 mm, preferably at least 0.1 mm, more preferably at least 0.2 mm, and most preferably at least 0.3 mm.

[0039] The cover ring, especially the cam holder, can have a thread for A guide rail can be accommodated. The nozzle ring cam can have a through-hole through which the guide rail extends. Additionally or alternatively, the clamping segment can have a through-hole (in addition to the insertion opening) through which the guide rail can extend. The guide rail allows for easier assembly of the cover ring with the nozzle ring.

[0040] The nozzle ring cam and the cover ring cam receptacle can also be considered as a cam-cam receptacle pair. In one embodiment, the axial turbine has a plurality of cam-cam receptacle pairs, which are arranged spaced apart from one another in the circumferential direction of the outer ring. For each cam-cam receptacle pair, the axial turbine preferably has at least one (for example two) fastening means, which releasably connects the outer ring to the cover ring in the region of the respective cam-cam receptacle pair in the axial direction. Additionally or alternatively, The axial turbine has a clamping segment for each cam / cam receiving pair, in particular, which exerts an axial force on the respective cam / cam receiving pair. Optionally, the axial turbine can have a clamping projection for each cam / cam receiving pair. The additional cam / cam receiving pairs and / or additional clamping segment / clamping projection pairs arranged on the axial turbine can thus be designed according to the above description.

[0041] In one embodiment, the respective cams differ Cam receiver pairs differ in their geometric design. For example, the respective cam / cam receiver pairs can differ from the other cam / cam receiver pairs in terms of their circumferential length. This allows only one cam to engage in a specific cam receiver. This advantageously ensures that the nozzle ring is mounted in a specific, intended orientation.

[0042] In an exemplary embodiment, the axial turbine has three cam Cam receiver pairs and three clamping segment / clamping projection pairs. Each of the three clamping segment / clamping projection pairs can have two insertion openings or through holes. The nozzle ring can be removably attached to the cover ring using six fasteners.

[0043] The axial turbine described herein advantageously allows the assembly and disassembly of various components from both a “cold” side (compressor side) and a “warm” side (turbine side).

[0044] The axial turbine can be designed using a “cartridge concept”. The "cartridge" can include the shaft and the turbine impeller mounted on the shaft. After removing the cartridge, access to other components of the axial turbine is possible, such as the diffuser, cover ring, and nozzle ring. The nozzle ring and / or cover ring can be designed to be removed axially from the compressor side (from a "cold" side). However, removing the nozzle ring or cover ring from a "cold" side is time-consuming and particularly useful when a major repair or maintenance is required, rather than simply servicing or replacing the nozzle ring or cover ring.

[0045] Furthermore, the nozzle ring and / or the cover ring can be designed to be axially removed from the turbine side (from a "warm" side). For this purpose, at least an outer part of the gas inlet housing can be dismantled. In particular, this embodiment enables a reduction in the time required for assembly and disassembly, which has a positive effect on service costs. If only maintenance or replacement of the nozzle ring is required, and / or the cover ring is desired, this can be achieved with little time by means of turbine-side access to the nozzle ring and / or the cover ring.

[0046] According to one embodiment, the axial turbine has between the The outer ring (and optionally the cover ring) of the nozzle ring and the gas outlet casing of the turbine housing form a gap. This gap allows axial access to the fastener (especially after removing parts of the gas inlet casing). This allows the fastener to be loosened, allowing the nozzle ring to be disassembled and removed from the warm side.

[0047] In a further embodiment, the space can have an axial Allow access to the fastening element (especially after removing parts of the gas inlet casing). This allows the fastening element to be loosened, allowing the cover ring to be disassembled and removed from the warm side. By successively loosening the fastening element and fastening element, the nozzle ring and then the cover ring on the turbine side can be removed first. Alternatively, only the fastening element(s) can be loosened and then the cover ring and nozzle ring can be removed together from the turbine side.

[0048] According to a further embodiment, a turbomachine is provided, in particular an exhaust gas turbocharger. The turbomachine comprises an axial turbine according to one of the embodiments described herein and a compressor connected to the shaft.

[0049] According to a further embodiment, a method for disassembling a nozzle ring is provided. The nozzle ring is installed in an axial turbine and arranged in a turbine housing of the axial turbine. The axial turbine comprises fastening means which detachably connect an outer ring of the nozzle ring to a cover ring of the axial turbine radially outward in the axial direction. The axial turbine can further have fastening elements which detachably connect the cover ring to a turbine diffuser of the axial turbine radially outward in the axial direction. The turbine housing and the nozzle ring are shaped such that a gap is provided between the outer ring of the nozzle ring and the turbine housing.

[0050] In one embodiment, the method comprises the steps of: removing an outer part of a gas inlet casing of the turbine casing of the axial turbine; removing the fastening means by means of an axial access in the intermediate space; and axially removing the nozzle ring from the turbine casing on the turbine side.

[0051] Optionally, the method may further comprise the steps of: removing the Fastening element by means of an axial access in the gap; and axial turbine-side removal of the cover ring from the turbine housing.

[0052] In a further embodiment, the procedure comprises the following steps: Removing an outer portion of a gas inlet casing of the turbine casing of the axial turbine; removing the fastener by means of an axial access in the intermediate space; and axially removing the nozzle ring and the cover ring from the turbine casing on the turbine side.

[0053] In particular, the method can include a common axial turbine-side Removing the nozzle ring and the cover ring from the turbine housing.

[0054] The axial turbine and / or the nozzle ring and / or the cover ring may be designed according to one of the embodiments described herein.

[0055] In a further embodiment, the use of a combination comprising a nozzle ring and a cover ring for turbine-side installation in and / or removal from an axial turbine for a turbomachine is described. The combination comprises a nozzle ring having an outer ring. The nozzle ring is configured to be installed in a turbine housing of the axial turbine and to be arranged at least partially upstream of a turbine wheel of the axial turbine. Furthermore, the combination comprises a cover ring configured to be installed in a turbine housing and to be arranged downstream of the nozzle ring. The combination comprises a fastening means which releasably connects the outer ring to the cover ring radially outward in the axial direction. A downstream end portion of the outer ring has a radially outwardly projecting nozzle ring cam, and an upstream end portion of the cover ring has a cover ring cam receptacle.The nozzle ring cam engages with the cover ring cam receptacle.

[0056] The outer ring may have a clamping segment, wherein the The fastener extends through an insertion opening in the clamping segment. Optionally, the fastener can engage a thread in the cover ring.

[0057] In a further embodiment, a composite assembly comprising a nozzle ring and a cover ring is provided, in particular for turbine-side installation in and / or removal from an axial turbine for a turbomachine. The assembly comprises a nozzle ring having an outer ring. The nozzle ring is configured to be installed in a turbine housing of the axial turbine and to be arranged at least partially upstream of a turbine wheel of the axial turbine. Furthermore, the assembly comprises a cover ring configured to is to be installed in a turbine housing and positioned downstream of the nozzle ring. The assembly comprises a fastening means that releasably connects the outer ring to the cover ring radially outward in the axial direction. A downstream end portion of the outer ring has a radially outwardly projecting nozzle ring cam, and an upstream end portion of the cover ring has a cover ring cam receptacle. The nozzle ring cam engages the cover ring cam receptacle.

[0058] The outer ring may have a clamping segment, wherein the The fastener extends through an insertion opening in the clamping segment. Optionally, the fastener can engage a thread in the cover ring. Short description of the characters

[0059] The invention is explained in more detail below using embodiments, without these being intended to limit the scope of protection defined by the claims.

[0060] The accompanying drawings illustrate embodiments and, together with the description, serve to explain the principles of the invention. The elements of the drawings are relative to one another and are not necessarily to scale. Like reference numerals designate similar parts.

[0061] The figures show:

[0062] Figure 1 shows an axial turbine according to an embodiment as Exploded view.

[0063] Figure 2 shows part of an axial turbine according to one embodiment.

[0064] Figure 3 shows part of an axial turbine according to one embodiment.

[0065] Figure 4 shows an enlarged view of an area from Figure 3.

[0066] Figure 5 shows an axial turbine according to one embodiment. Detailed description

[0067] The following detailed description refers to the enclosed Reference is made to the drawings which form a part hereof, and in which is shown by way of illustration specific embodiments in which the invention may be practiced. It is to be understood that other embodiments may be utilized and structural or logical changes may be made without departing from the scope of the present invention. The following detailed description, therefore, is not to be taken in a limiting sense, and the scope of the present invention is determined by the appended claims. The described embodiments employ specific language that should not be construed to limit the scope of the appended claims.

[0068] Figures 1 and 2 show a portion of an axial turbine 100 for a turbomachine according to one embodiment. For clarity, some components of the axial turbine 100 are not shown. In particular, the axial turbine 100 includes a turbine housing, a shaft 170, and a turbine impeller 180 arranged in the turbine housing and mounted on the shaft 170. Figure 1 is an exploded view. Thus, the components of the axial turbine 100 are shown in an unassembled state.

[0069] The axial turbine 100 includes a nozzle ring 110. The nozzle ring 110 has an outer ring 112, an inner ring 114, and guide vanes 113 arranged between the outer ring 112 and the inner ring 114. The turbine housing includes a cap 111 connected to the nozzle ring 110. The outer ring 112, guide vanes 113, the inner ring 114, and the cap 111 are all integrally formed. The nozzle ring 110 is arranged within the turbine housing (not shown).

[0070] Furthermore, the axial turbine 100 has a cover ring 120. The cover ring is arranged within the turbine housing (not shown) and downstream of the nozzle ring 110.

[0071] The axial turbine 100 has six fastening means 140, which The outer ring 112 is detachably connected to the cover ring 120 radially outward in the axial direction. The outer ring 112 has three clamping segments 116, and the cover ring 120 has three clamping projections 122 (only two clamping segments 116 and two clamping projections 122 are fully illustrated in Figure 1). Two fastening elements 140 each connect a clamping segment 116 to the outer ring 112.

[0072] Furthermore, the outer ring 112 has three nozzle ring cams 115 and the Cover ring 120 has three corresponding cam receptacles 121 (only one nozzle ring cam 115 and one cam receptacle 121 are fully shown in Figure 1).

[0073] The axial turbine 100 further includes a turbine diffuser or diffuser 130. The diffuser 130 and the cover ring 120 are each designed as separate components and are connected to one another by means of fastening elements 150. The cover ring 120 has a plurality of insertion openings 125, and the turbine diffuser 130 has a corresponding number of threads 131 for receiving the fastening elements 150. The fastening elements 150 each extend through one of the insertion openings 125 and engage in one of the threads 131 of the diffuser 130.

[0074] Figures 2 and 3 each show a cross-sectional view of the axial turbine 100 according to one embodiment. The area shown in Figures 2 and 3 illustrates the connection between nozzle ring 110 and cover ring 120.

[0075] The nozzle ring cam 115 of the nozzle ring 110 lies on the corresponding Cam receptacle 121 of the cover ring 120. The clamping segment 116 of the nozzle ring 110 rests on the clamping projection of the cover ring 120.

[0076] By fastening the two fastening means 140 shown, the Clamping segment 116 is pressed against the clamping projection 122. Pressing the clamping segment 116 against the clamping projection 122 causes the nozzle ring cam 115 to be pressed against the cam receptacle 121. While an axial distance may exist between the nozzle ring cam 115 and the clamping segment 121 in a non-assembled state, the nozzle ring cam 115 and the clamping segment 121 come into contact with one another by connecting the nozzle ring 110 and the cover ring 120, thereby creating a contact surface between the nozzle ring cam 115 and the clamping segment 121. This pressing action can cause the nozzle ring cam 115 to press the clamping segment 121 axially upstream or the nozzle ring cam 115 to protrude axially into the clamping segment 121. In Figure 3, and even more clearly in the enlarged view in Figure 4, the projection of the nozzle ring cam 115 into the clamping segment 121 is indicated by a thick black line.

[0077] The cover ring 120 may have a thread 124 for receiving a Guide rail. The nozzle ring cam 115 can have a through-hole through which the guide rail extends. Additionally or alternatively, the clamping segment 121 can have a through-hole (in addition to the insertion opening 117) through which the guide rail can extend. The guide rail allows for easier assembly of the cover ring 120 with the nozzle ring 110.

[0078] In Figure 5, the axial turbine 100 is shown with nozzle ring 110, cover ring 120 and Diffuser 130 is shown. The axial turbine 100 has a turbine housing 160. The turbine housing includes a gas inlet housing 161 and a gas outlet housing 162. The Diffuser 130 and cover ring 120 are arranged within gas outlet housing 162. Nozzle ring 110 is arranged partially within gas inlet housing 161 and partially within gas outlet housing 162. Nozzle ring 110 and gas outlet housing 162 are shaped to create a gap 163. After at least partial removal of gas inlet housing 161, gap 163 allows axial access to nozzle ring 110. This allows access to fastening means 140. After loosening and removing fastening means 140, nozzle ring 110 can be removed from the turbine side.

[0079] The shaft 170 defines the longitudinal axis 190, or rather, the axial direction and the radial direction. Figure 5 illustrates the longitudinal axis 190 as a dashed-dotted line.

[0080] Furthermore, the gap 163 can provide access to the fastening element 150. After loosening and removing the fastening elements 150, the cover ring 120 can be removed on the turbine side.

[0081] Although specific embodiments have been shown and described herein, it is within the scope of the present invention to suitably combine or modify the shown embodiments without departing from the scope of the present invention.

[0082] List of reference symbols 100 axial turbine 110 Nozzle ring 111 Calotte 112 Outer ring 113 guide vanes (of the nozzle ring) 114 Inner ring (of the nozzle ring) 115 Nozzle ring cam 116 clamping segment 117 Insertion opening 120 cover ring 121 cam holder 122 clamping overhang 123 guide hole 124 thread for mounting a guide rail 125 Insertion opening of the cover ring Turbine diffuser Thread in the turbine diffuser (to accommodate the fastening element) Fasteners Fastening element Turbine housing Gas inlet housing Gas outlet housing space Wave turbine runner Longitudinal axis

Claims

Patent claims 1. An axial turbine (100) for a turbomachine, in particular for an exhaust gas turbocharger, comprising: a turbine housing (160); a turbine impeller (180) arranged in the turbine housing (160) and mounted on a shaft (170); a nozzle ring (110) arranged in the turbine housing (160) and at least partially upstream of the turbine impeller (180), the nozzle ring having an outer ring (112); a cover ring (120) arranged in the turbine housing (160) and downstream of the nozzle ring (110), a fastening means (140) which releasably connects the outer ring (112) to the cover ring (120) radially outward in the axial direction; wherein a downstream end portion of the outer ring (112) has a radially outwardly projecting nozzle ring cam (115) and an upstream end portion of the cover ring (120) has a cover ring cam receptacle (121), and wherein the nozzle ring cam (115) engages in the cover ring cam receptacle (121).

2. Axial turbine according to claim 1, further comprising a spherical cap (111) which is arranged on an upstream end section of the nozzle ring, wherein the spherical cap (111) is fastened exclusively to an inner ring (114) of the nozzle ring (110) or wherein the spherical cap (111) is formed integrally with the nozzle ring (110), in particular the inner ring (114) of the nozzle ring (110).

3. Axial turbine (100) according to one of the preceding claims, wherein the outer ring (112) has a clamping segment (116), wherein the fastening means (140) extends through an insertion opening (117) in the clamping segment (116); and optionally wherein the fastening means (140) engages a thread in the cover ring (120).

4. Axial turbine (100) according to claim 3, wherein the nozzle ring cam (115) protrudes into the clamping segment (116) by at least 0.05 mm, preferably at least 0.1 mm, more preferably at least 0.2 mm and most preferably at least 0.3 mm.

5. Axial turbine (100) according to claim 3 or 4, wherein the clamping segment (116) has two insertion openings (117), wherein the nozzle ring cam (115) is arranged between the two insertion openings as seen in the circumferential direction.

6. The axial turbine (100) according to any one of claims 3 to 5, wherein the clamping segment (116) is arranged upstream at a distance from the nozzle ring cam (115); and / or wherein the clamping segment (116) at least partially overlaps the nozzle ring cam (115) when viewed in the circumferential direction.

7. Axial turbine (100) according to one of claims 3 to 6, wherein the cover ring (120) has a clamping projection (122) for receiving the clamping segment (116).

8. Axial turbine (100) according to one of the preceding claims, wherein the axial turbine is configured such that by axially fastening the outer ring (112) to the cover ring (120) by the fastening means (140), the nozzle ring cam (115) is pressed into the cover ring cam receptacle (121), and in particular the clamping segment (116) is pressed against the clamping projection (122).

9. Axial turbine (100) according to one of the preceding claims, further comprising a turbine diffuser (130) arranged at least partially downstream of the turbine impeller (180).

10. The axial turbine (100) of claim 9, wherein the turbine diffuser (130) is formed integrally with the cover ring (120).

11. Axial turbine (100) according to claim 9, wherein a downstream end portion of the cover ring (120) is connected to an upstream end portion of the turbine diffuser (130) is fastened; in particular wherein the turbine diffuser (130) is detachably connected to the cover ring (120) by means of a fastening element (150), wherein the fastening element (150) extends along an insertion opening (125) of the cover ring (120) and engages in a thread (131) in the turbine diffuser (130).

12. Axial turbine (100) according to one of the preceding claims, wherein the nozzle ring cam (115) and the cover ring cam receptacle (121) form a cam-cam receptacle pair and the axial turbine (100) has at least three cam-cam receptacle pairs which are arranged spaced apart from one another in the circumferential direction of the outer ring (112).

13. Axial turbine (100) according to one of the preceding claims, wherein the nozzle ring (110) and / or the cover ring (120) is designed to be removed axially on the turbine side.

14. Method for disassembling a nozzle ring (110) which is installed in an axial turbine (100) and arranged in a turbine housing (160) of the axial turbine, wherein the axial turbine (100) has fastening means (140) which detachably connect an outer ring (112) of the nozzle ring (110) to a cover ring (120) of the axial turbine (100) radially outward in the axial direction, and optionally wherein the axial turbine (100) has fastening elements (150) which detachably connect the cover ring (120) to a turbine diffuser (130) of the axial turbine (100) radially outward in the axial direction, wherein the turbine housing (160) and the nozzle ring (110) are shaped such that an intermediate space (163) between the outer ring (112) of the nozzle ring (110) and the Turbine housing is provided, the method comprising: Removing an outer part of a gas inlet casing (161) of the turbine casing (160) of the axial turbine (100); Removing the fastening means (140) by means of an axial access in the intermediate space (163); and axially removing the nozzle ring (110) from the turbine housing (160) on the turbine side; or Removing the fastening element (150) by means of an axial access in the intermediate space (163); and axially removing the nozzle ring (110) and the cover ring (120) from the turbine housing (160) on the turbine side.

15. Use of a combination comprising a nozzle ring (110) and a cover ring (120) for turbine-side installation in and / or removal from an axial turbine (100) for a turbomachine, the combination comprising: a nozzle ring (110) which has an outer ring (112) and is designed to be installed in a turbine housing (160) of the axial turbine (100) and to be arranged at least partially upstream of a turbine impeller (180) of the axial turbine (100); a cover ring (120) which is designed to be installed in a turbine housing (160) and to be arranged downstream of the nozzle ring (110); a fastening means (140) which releasably connects the outer ring (112) to the cover ring (120) radially outward in the axial direction;wherein a downstream end portion of the outer ring (112) has a radially outwardly projecting nozzle ring cam (115) and an upstream end portion of the cover ring (120) has a cover ring cam receptacle (121), and wherein the nozzle ring cam (115) engages in the cover ring cam receptacle (121);

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