EP2558697A1

EP2558697A1 - Housing for an impeller

Info

Publication number: EP2558697A1
Application number: EP11779350A
Authority: EP
Inventors: Stefan Köhler
Original assignee: Voith Patent GmbH
Current assignee: Voith Patent GmbH
Priority date: 2010-11-09
Filing date: 2011-11-03
Publication date: 2013-02-20
Also published as: JP2013541671A; WO2012062428A1; CN102971505A; DE102010050669A1; US20130149114A1

Abstract

The invention relates to a housing for an impeller of a turbomachine having a flow channel enclosed by a housing wall; a valve flap by which a flow opening in the housing wall can be selectively closed or opened; and a shaft connected to the valve flap, wherein the shaft is guided through an opening in the housing wall to the exterior of the flow channel. The invention is characterized in that the opening comprises an opening width greater than the greatest diameter of the smallest projection area of the valve flap and of the part of the shaft protruding into the flow channel in the assembled state, and that the opening is closed in the assembled state by a cover through which the shaft runs.

Description

Housing for an impeller

The invention relates to a housing for an impeller of a turbomachine according to the closer defined in the preamble of claim 1.

Turbo machines are known from the general state of the art. The impellers of such turbomachines are typically exhaust gas turbines or compressor wheels. Both are combined

used together for example in a so-called exhaust gas turbocharger. The exhaust gas turbine alone may also be part of a so-called turbo-compound system.

Exhaust gas turbines are typically used in motor vehicles and there mostly in conjunction with an internal combustion engine. The

Exhaust gas turbines use thermal energy and pressure energy in the exhaust gases, in particular in the exhaust gases of the internal combustion engine in order to recover energy therefrom. About the recovered energy can then be driven for example in an exhaust gas turbocharger, a compressor to compress the internal combustion engine supplied fresh air. In a turbo-compound system, the energy recovered from the exhaust gases by means of the exhaust gas turbine typically serves to provide additional mechanical power for driving the motor vehicle. Other comparable applications of exhaust gas turbines known from the prior art can also use the recovered energy for other purposes, for example for driving ancillaries or the like.

Now it is so that very often in the field of turbochargers, but also in the field of turbo-compound systems, so-called wastegate valves, blow-off valves or air recirculation valves are provided. These valves are typically constructed in the form of flaps, which have an opening in a flow channel, by which gas flows from or to the impeller or the wheels, can open, so as to be able to blow off the gas, for example, in the area after the impeller can. In the case where the valve device is used in the region of the exhaust gas turbine, it is typically called a wastegate valve. It can then be used to improve the controllability of the exhaust gas turbine. If, in such situations, the exhaust pressure across the exhaust gas turbine is reduced by such a wastegate valve, the losses are minimized. The valve device with a similar construction can also be used in the area of the compressor turbine as an impeller of the turbomachine. It can then, for example, open a bypass around the compressor turbine, either as a mere safety valve or to blow off already compressed air after the compressor turbine, so as to regulate the air supply. However, the latter variant, which is quite customary in the prior art, is generally not preferable because of the associated energy losses.

A typical structure for such a valve device is the realization of the valve by a flow opening in a housing wall in the housing for the impeller, which can be closed or opened by a movable relative to the flow opening flap. Typically, such a flap is actuated by a shaft which projects through the housing to the outside and is provided for example with a lever and an adjusting element. On the located in the housing side of the shaft then the flap is rotationally carried out with the shaft, for example, welded off-center. By a

Rotary movement of the shaft can be as the flap on the flow opening in the housing wall to close or can be closed by the

Flow opening are pivoted away to release this. Since the flap is pivoted into the region of the flow channel, the structure with the flap also has the advantage that the flow channel through the flap in is narrowed his flow-through cross-section. If the shaft and thus the pivot axis of the flap are now arranged in the direction of flow of the medium downstream of the flow opening in the housing wall, then an advantageous back pressure can be generated, which promotes the outflow of the medium through the now released from the flap flow opening.

The problem with such a construction is that an opening for passing the shaft for actuating the valve flap is typically provided in the region of the housing wall. This opening for the shaft is either a bore adapted to the diameter of the shaft through the housing wall or a bearing sleeve pressed into the housing wall for the shaft. After the shaft through the opening in the housing wall

or the pressed bearing sleeve has been introduced, wherein the shaft can optionally also be pressed together with the bearing sleeve in the housing wall, now the valve flap must be connected to the shaft. This is often done by welding, which then has to be done in the typically very cramped area of the flow channel. In this case, an exact fixation of the flap over the flow opening, which is to close or release this required. This is very complicated due to the typically cramped space and requires a correspondingly high installation time. Due to the cramped space it also often leads to assembly errors, which then have a leak between the valve flap and the flow opening result. The housing for the impeller must then be revised or possibly even discarded.

In addition, if a bearing sleeve is pressed into an opening in the housing, must be on a suitable mounting of the housing during the

Be respected. Since housings for impellers typically have spiral channels around the largest diameter of the impeller are

Buckles, diameters and radii of the individual housing depending on the type of construction and Performance often very different. Nevertheless, in order to safely and reliably accomplish the pressing of a bearing sleeve, a suitable receiving device must be present for each type of housing to ensure that the housing is taken up securely and stably perpendicular to the press-in that it during pressing

applied pressure without damage resists. This is disadvantageous due to the relatively high number of different housings during assembly with a high cost in terms of holding devices and the frequent tool change required during pressing.

It is therefore an object of the present invention to provide a housing for an impeller of a turbomachine, for example an exhaust gas turbine, which avoids the disadvantages mentioned and offers the possibility to mount a valve flap easily, safely and reliably in the housing.

According to the invention this object is achieved by the features mentioned in the characterizing part of claim 1. Further advantageous embodiments and further developments of the structure according to the invention also emerge from the dependent claims.

In the housing for an impeller according to the invention, it is provided that the opening through which the shaft is guided through the housing wall to the outside of the flow channel, having an opening width which is greater than the largest diameter of the smallest projection surface of the valve flap and the mounted state in the flow channel projecting part of the shaft, and that this opening is closed in the mounted state with a cover through which the shaft passes. The housing according to the invention therefore provides an opening in the region of a housing wall around the flow channel, which is so large that valve flap and shaft can be introduced in the already connected state through this opening in the flow channel. The structure can be like this be mounted very easily, reliably and with high accuracy, since the connection of the valve flap with the shaft is omitted in the interior of the flow channel. The valve flap and the shaft can rather be preassembled outside the housing and then introduced through the opening in the flow channel. The opening is then closed by a lid in the assembled state, the shaft passing through the lid. The lid can in principle be connected to the housing in any desired manner. A detachable connection, which takes place, for example, by screwing the lid to the housing, is in terms of any maintenance or

Such certainly beneficial. In principle, however, it is also conceivable to press the cover with the housing or to weld.

The cover itself can also be preassembled together with shaft and valve flap as a unit, so that these components can be introduced during assembly in the flow channel or the housing and connected to it. Valve flap, flow opening, opening and

Connection of the lid can be done on different series of

Housings always be carried out the same way, so that the pre-assembled unit can be easily and efficiently integrated into different housing types with different geometric outer shapes. Since the unit can now be constructed and pre-assembled identical for different types of housings, due to the higher numbers here

Saves manufacturing and manufacturing costs. In a particularly advantageous development of the construction according to the invention, the cover is designed to be round and at least partially provided on its end side with a thread which cooperates with a thread in the region of the correspondingly formed opening. This particularly simple and efficient construction makes it possible to carry out the cover and its possibility for attachment in one piece so that, for example, a preassembled Unit of cover, shaft and valve flap can be easily inserted through the opening in the housing and bolted to it.

The cover may be embodied as a single component which has an opening, for example centrally or eccentrically arranged, through which the shaft, ideally in sealing engagement with the cover,

passed through. The eccentric arrangement of the opening offers the possibility of a rotation of the lid about its center

Shift the position of the shaft to reach. As a result, any tolerance deviations between the valve flap and the flow opening can be compensated.

Additionally or alternatively, it can also be provided that the cover has a bearing sleeve for the shaft. Such a bearing sleeve can for example be made of a suitable bearing material, while the lid itself can be made of another suitable for the connection and the introduction of a permanently stable thread more suitable material.

In a particularly favorable development thereof, the bearing sleeve is made pressed with the lid. Such compression of the bearing sleeve with the lid substantially corresponds to the assembly, as it is customary from the prior art. However, no different holding devices for the housing must be provided, since the sleeve is pressed only with the lid, which is ideally standardized in all series of the housing and thus requires only a single receiving device during pressing. The bearing sleeve can then, as in the previous structure without having to change proven materials and dimensions, be pressed with the lid. The entire structure of lid with pressed-bearing sleeve, shaft and attached thereto, for example, welded valve flap, can then be preassembled independently of the housing of the impeller and stored in larger quantities. In the Assembly then only this preassembled unit must be integrated into the housing by inserting the valve flap and screwing the lid according to the particularly preferred embodiment described above. In a further embodiment, it can also be provided that the shaft has a lever on the side facing away from the valve flap. This can also be attached directly to the pre-assembly of the unit, for example, welded, so that the unit can be connected directly to an actuator, such as a servomotor, a hydraulic or pneumatic actuator or the like for actuating the valve flap to open or close the flow opening in the flow channel can.

The preferred use of such a housing is in use as a so-called wastegate valve for an exhaust gas turbine of a turbocharger or a turbo-compound system. But also the use for the realization of a blow-off valve for a compressor in a turbocharger is conceivable. According to a very favorable embodiment of the housing according to the invention, it is accordingly provided that the impeller is an exhaust gas turbine and / or a compressor wheel of an exhaust gas turbocharger.

Further advantageous embodiments of the structure according to the invention also result from the embodiment described below, which is explained in more detail with reference to the figures.

Showing:

Figure 1 is a schematic representation of an exhaust gas turbocharger; and a possible embodiment of the valve device according to the invention in the field of exhaust gas turbine.

The following embodiment describes the functionality and structure of a valve device 1 for an exhaust gas turbine 2 using the example of a turbocharger 3, which can be seen in the representation of Figure 1 in a schematic view. The exhaust gas turbine or turbine 2 of the exhaust gas turbocharger 3 is connected in a manner known per se via a shaft 4 to a compressor or a compressor wheel 5. The turbine 2 flows through the arrow designated A hot exhaust gas, for example from the range of an internal combustion engine, not shown, to. This hot exhaust gas is expanded in the turbine 2 and then passes through the arrow designated a in the area of the environment. The resulting

mechanical power is transmitted via the shaft 4 directly to the compressor. 5

transferred, which sucks fresh air from the environment according to the arrow b, this compressed and fed according to the arrow B as combustion air of the just mentioned internal combustion engine. This structure is known per se from the prior art. He will describe the function of the valve device 1 explained below using the example of an exhaust gas turbocharger 3 in more detail. Likewise, a comparable structure in a turbo-compound system would be applicable, which also has the exhaust gas turbine or turbine 2, which then on the shaft 4 but no compressor 5, but typically drives a gear or pinion. About this pinion, the power obtained in the turbine 2 power is then used elsewhere, for example, provided via a hydrodynamic coupling and a corresponding gear of the crankshaft as a supplemental power available. Another possible use is in the area of the compressor wheel 5. Here too, air could be bypassed via a valve device 1

Be performed compressor 5 or blown out of the range of the compressor 5. The valve device used for this purpose can analogously Inventive valve device 1 be constructed, which will be described and explained in more detail below using the example of the exhaust gas side.

In exhaust gas turbochargers 3 as well as in turbo-compound systems, it happens in certain operating situations that the exhaust gas A is not passed through the turbine 2, but is to be wholly or typically partially guided around the turbine 2. For this purpose, the valve device 1, which is also referred to as Umblaseventil, recirculation valve, blow-off valve or wastegate valve. It connects the region of the exhaust gas A flowing into the turbine 2 with the region of the exhaust gas a leaving the turbine 2. On this valve device 1 will now be discussed in more detail below.

In the illustration of Figure 2, the valve device 1, which was indicated in principle in Figure 1, to recognize in their concrete structure. The valve device 1 consists of a valve flap 6, which can close and release a dashed line indicated here flow opening 7 in a housing wall 8. The housing wall 8 encloses a flow channel 9, for example, the inlet space for the exhaust gas A in the exhaust gas turbine 2. The housing wall 8 is part of a housing, in this case, for example, part of the turbine housing. The valve device 1 is next to the valve flap 6 of a shaft 10, which is arranged in the embodiment shown here off-center of the valve flap 6 and connected via a connecting element 11 with this. The connection can in particular by a

Welding the valve flap 6 with the connecting element 11 and / or the shaft 10 done. The valve device 1 also has at its the

Flow channel 9 äbgewandten end of the shaft 10 to a lever 12, which is also connected to the shaft 10, for example, welded. The lever 12 is connected to an actuating device 13, for example a servomotor, a hydraulic or pneumatic piston or the like, in connection. By a rotating movement on the lever 12, the valve flap 6 can be made of the in FIG shown closed position of the flow opening 7 to pivot about the axis of the shaft 10 and are so, depending on the pivoting angle, a continuously expanding cross section of the flow opening 7 free. The shaft 10 is mounted in the embodiment shown here in a bearing sleeve 14 so that these via the lever 12 and the

Actuator 13 is rotatable, and that at the same time the best possible sealing of the flow channel 9 in the region between the shaft 10 and the bearing sleeve 14 is ensured. The bearing sleeve 14 is introduced into a lid 15, for example, pressed. The lid 15 sits in the mounted

State in an opening 16 in the housing wall 8. Via a thread 17 housing wall 8 and cover 15 are screwed together. In addition to the thread 17 on its region of the end faces facing the flow channel 9, the cover 15 also has, in the region facing away from the flow channel 9, a collar 18 which has a sealing surface 19 on its surface facing the flow channel. This sealing surface 19, together with a corresponding, surrounding the opening 16 sealing surface 20 a very good seal between the lid 15 and the housing wall 8 in the assembled state.

The opening 16 now has an opening width D, which corresponds to a circular diameter in the embodiment shown in Figure 2. In other embodiments of the opening 16, for example, in a flanged from the outside of the housing wall 8 lid 15, the opening could also have other shapes, such as a rectangular shape, an oval shape or the like. In this case, the opening width D would be the largest opening width. The opening width D is to be chosen in each case so that it is greater than the largest diameter of the smallest

Projection surface of the valve flap 6 and the mounted state in the

Flow channel 9 protruding part of the shaft 10. The largest diameter of the smallest projection surface is exemplified by indicated in Figure 2 with d diameter. The largest diameter α of this smallest

Projection surface of the protruding into the flow channel 9 in the assembled state parts of the valve device 1 can - in the example shown by slight tilting - through the larger opening 16 in the mounted state in the

Flow channel 7 are introduced. A complex assembly, for example, the elaborate welding of the valve flap 6 with the connecting element 11 and / or the shaft 10 in the interior of the flow channel 7, can thus be avoided. The structure of the valve device 1 with valve flap 6,

Connecting element 11, shaft 10, bearing sleeve 14, cover 15 and optionally with the lever 12 can thus be pre-assembled outside the flow channel 9 and can then be introduced through the opening 16 in the flow channel and mounted by tightening the lid 15. The effort in terms of assembly is minimized.

Claims

claims

1. housing for an impeller (2, 5) of a turbomachine (3) with

1.1 a flow channel (9) which is surrounded by a housing wall (8),

1.2 a valve flap (6), through which a flow opening (7) in the

Housing wall (8) is either lockable or releasable,

1.3 a shaft (10) which is connected to the valve flap (6), wherein

1.4 the shaft (10) through an opening (16) in the housing wall (8) after

is guided outside the flow channel (9),

characterized in that

1.5 the opening (16) has an opening width (D) which is greater than the largest diameter (d) of the smallest projection area of the valve flap (6) and the part of the shaft (10) projecting into the flow channel (9) in the mounted state, and that the opening (16) in the assembled state with a lid (15) through which the shaft (10) extends, is closed.

Housing according to claim 1, characterized in that the cover (15) with the housing wall (8) is screwed.

Housing according to claim 1 or 2, characterized in that the cover (15) is formed round and at its end face at least partially provided with a thread (17) which cooperates with a thread (17) in the region of the correspondingly formed opening (16) ,

Housing according to claim 3, characterized in that the cover (15) on its the flow channel (9) facing side of the end faces the thread (17) and on its side facing away from the flow channel a collar (18) having at least one sealing surface (19) ,

5. Housing according to one of claims 1 to 4, characterized in that an axis of rotation of the lid (15) and the axis of rotation of the shaft (10) in the region of the lid (15) are arranged spaced from each other.

6. Housing according to one of claims 1 to 5, characterized in that the cover (15) has a bearing sleeve (14) for the shaft (10).

7. Housing according to claim 6, characterized in that the bearing sleeve (14) with the lid (15) is made compressed.

8. Housing according to one of claims 1 to 7, characterized in that the valve flap (6) and the shaft (10) are at least indirectly welded together.

9. Housing according to one of claims 1 to 8, characterized in that the shaft (10) on the valve flap (6) facing away from a lever (12).

10. Housing according to one of claims 1 to 9, characterized in that the impeller as exhaust gas turbine (2) and / or as a compressor wheel (5) of an exhaust gas turbocharger (3) is formed.