HOUSING FOR A BLADE WHEEL

Abstract

The present invention relates to a housing for a blade wheel of a turbo machine including a flow channel which is enclosed by a housing wall; a valve flap for selectively sealing or releasing a flow opening in the housing wall; and a shaft which is connected with the valve flap. The shaft is guided through an opening in the housing wall to the outside of the flow channel. The opening has an opening width which is larger than the largest diameter of the smallest projected area of the valve flap and of the part of the shaft protruding into the flow channel in the mounted state, and the opening is sealed in the mounted state by a cover through which the shaft extends.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

This is a continuation of PCT application No. PCT/EP2011/005537, entitled “A HOUSING FOR A BLADE WHEEL”, filed Nov. 3, 2011, which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a housing for a blade wheel of a turbo machine.

2. Description of the Related Art

Turbo machines are known from the general state of the art. The blade wheels of such turbo machines typically concern exhaust gas utilization turbines or compressor wheels. Both are used in combination with one another in a so-called exhaust gas turbocharger. The exhaust gas utilization turbine can further be a part of a so-called turbocompound system.

Exhaust gas utilization turbines are typically used in motor vehicles and mostly in connection with an internal combustion engine. The exhaust gas utilization turbines utilize thermal energy and pressure energy in the exhaust gases, especially in the exhaust gases of the internal combustion engine, in order to recuperate energy therefrom. A compressor wheel can be driven in an exhaust gas turbocharger via the recuperated energy for example in order to compress the fresh air supplied to the internal combustion engine. In the case of a turbocompound system, the energy recuperated by means of the exhaust gas utilization turbine from the exhaust gases will typically be used to additionally provide mechanical power for driving the motor vehicle. Other comparable applications of exhaust gas utilization turbines as are known from the state of the art can utilize the recuperated energy in other ways, e.g. for driving auxiliary units or the like.

It is frequently the case in the area of turbochargers and also in the area of turbocompound systems that so-called wastegate valves, boost-pressure control valves or air recirculation valves are provided. These valves are typically arranged in the form of flaps which can open an opening in a flow channel through which gas flows from or to the blade wheel(s) in order allow the gas to be blown off into the region behind the blade wheel.

In the case in which the valve device is used in the area of the exhaust gas turbine it will typically be known as a wastegate valve. It can then be used for improving the controllability of the exhaust gas utilization turbine. If the exhaust gas pressure is reduced in such situations via the exhaust gas utilization turbine by such a wastegate valve, the losses will be minimized. The valve device with a comparable configuration can also be used in the region of the compressor turbine as a blade wheel of the turbo machine. It can then open a bypass around the compressor turbine for example, either as a pure safety valve or to blow off already compressed air after the compressor turbine in order to thereby control the air supply. The latter variant which is certainly common practice in the state of the art is generally not preferred due to the resulting energy losses.

A typical configuration for such a valve device is the realization of the valve by a flow opening in a housing wall in the housing for the blade wheel, which can be closed off or released by a flap which is movable in relation to the flow opening. Such a flap will be typically actuated by a shaft which protrudes to the outside through the housing and is provided with a lever or an actuating element for example. The flap is arranged in a torsion-proof manner with the shaft on the side of the shaft disposed within the housing, e.g. it is welded on in an off-center manner. As a result of a rotational movement of the shaft, the flap can be placed on the flow opening in the housing wall in order to close off the same, or it can be pivoted away from the flow opening in order to release the same. Since the flap is pivoted into the region of the flow channel, the configuration with the flap offers the further advantage that the flow channel is constricted in its flowable cross-section by the flap. If the shaft, and therefore the pivoting axis of the flap, is now arranged in the direction of flow of the medium after the flow opening in the housing wall, an advantageous dynamic pressure can consequently be generated which promotes the flowing off of the medium through the flow opening which has now been released by the flap.

The problem in connection with such a configuration is that typically an opening is provided in the region of the housing wall for guiding through the shaft for actuating the valve flap. This opening for the shaft is either a borehole through the housing wall adjusted to the diameter of the shaft or a bearing sleeve for the shaft pressed into the housing wall. Once the shaft has been introduced through the opening in the housing wall or the pressed-in bearing sleeve, wherein the shaft can optionally be pressed into the housing wall together with the bearing sleeve, it is now necessary to connect the valve flap with the shaft. This frequently occurs by welding, which in this case needs to occur in the typically very constricted area of the flow channel. It is necessary to provide a precise fixing of the flap over the flow opening which needs to close off or release the same. This is very laborious due to the typically constricted spatial conditions and therefore requires a respectively long period of mounting. As a result of the constricted spatial conditions, frequent mounting errors further occur, which then lead to leakages between the valve flap and the flow opening. The housing for the blade wheel then needs to be reworked or even rejected.

If a bearing sleeve needs to be pressed into an opening in the housing, it is further necessary to ensure suitable fixing of the housing during the pressing-in process. Since housings for blade wheels typically comprise spiral channels about the largest diameter of the blade wheel, archings, diameter and radii of the individual housings will frequently differ very strongly depending on configuration and performance. In order to nevertheless ensure the pressing in of the bearing sleeve in a secure and reliable manner, a suitable receiving apparatus must be provided for every single configuration of the housing in order to ensure that the housing is accommodated in a secure and stable manner perpendicularly to the pressing-in direction in such a way that it is capable of withstanding the pressure applied during pressing in without any damage. This is disadvantageous due to the comparatively high number of different housings in mounting concerning the holding apparatuses and the frequent changes of tools required for the pressing-in process.

What is needed in the art is a housing for a blade wheel of a turbo machine such as an exhaust gas utilization turbine, which avoids the aforementioned disadvantages and offers the possibility to mount a valve flap in a simple, secure and reliable manner in the housing.

SUMMARY OF THE INVENTION

The present invention provides a housing for a blade wheel having an opening through which a shaft is guided through the housing wall to the outside the flow channel, the opening having an opening width which is larger than the largest diameter of the smallest projected area of the valve flap and of the portion of the shaft protruding into the flow channel in the mounted state. Further, the opening is closed off by a cover in the mounted state through which the shaft extends. The housing in accordance with the present invention therefore provides an opening in the region of a housing wall about the flow channel, which is large enough that the valve flap and the shaft can be introduced in the already connected state through the opening in the flow channel. The configuration can thereby be mounted in a very simple and reliable manner with high precision because the connection of the valve flap with the shaft in the interior of the flow channel will be avoided. The valve flap and the shaft can be pre-mounted outside of the housing and can then be introduced through the opening into the flow channel. The opening will then be closed off by a cover in the mounted state, with the shaft extending through the cover. The cover can principally be connected in any desired manner with the housing. A releasable connection which occurs for example by screwing the cover onto the housing is certainly advantageous concerning potential maintenance work or the like. It is principally also possible to press the cover together with the housing or to weld it onto the housing.

The cover itself can also be pre-mounted together with the shaft and the valve flap as a modular unit, so that these components can be introduced during mounting into the flow channel or the housing and can be connected with the same. The valve flap, flow opening, opening and connection of the cover can always be provided with the same configuration over different lines of housings, so that the pre-mounted modular unit can be integrated in a simple and efficient way in different types of housings with different geometrical external shapes. Since the modular unit is respectively arranged in an identical manner for different types of housings and can be pre-mounted, it is possible to save production and manufacturing costs as a result of the higher piece numbers.

According to a further embodiment of the present invention, the cover is provided with a round configuration and is provided on its face side at least partly with a thread which cooperates with a thread in the region of the correspondingly arranged opening. This especially simple and efficient configuration allows arranging the cover and its possibility for integral fixing in such a way that a pre-mounted unit consisting of cover, shaft and valve flap can be introduced in a simple way through the opening into the housing and can be screwed together with the same.

The cover can be arranged as a single component which includes an opening arranged centrally or off-center, through which the shaft is guided, ideally in sealing engagement with the cover. The off-center arrangement of the opening offers the possibility of achieving a displacement of the position of the shaft by a rotation of the cover about its central point. This allows compensating potential tolerance deviations between the valve flap and the flow opening.

It can also be provided additionally or alternatively that the cover includes a bearing sleeve for the shaft. Such a bearing sleeve can be made of a suitable bearing material for example, whereas the cover itself can be produced from another material which is better suited for the connection and the introduction of a durably stable thread.

According to another embodiment of the present invention, the bearing sleeve is arranged to be pressed together with the cover. Such pressing together of the bearing sleeve with the cover substantially corresponds to mounting that has commonly been applied up until now in the state of the art. It is not necessary to provide any different holding apparatuses for the housing however because the sleeve will merely be pressed together with the cover, which is ideally standardized in all configurations of the housing and therefore merely requires one single receiving apparatus for pressing. As in the preceding configuration, the bearing sleeve can be pressed together with the cover without having to change any materials and dimensions used up until now. The entire configuration consisting of the cover with the pressed-in bearing sleeve, shaft and valve flap which is attached thereto, and welded thereon for example, can be pre-mounted independently from the housing of the blade wheel and can be put on stock in larger numbers. During mounting it is merely necessary to integrate the pre-mounted modular unit into the housing by inserting the valve flap and screwing in the cover according to the embodiment as described above.

It can also be provided in a further embodiment that the shaft includes a lever on the side facing away from the valve flap. It can also be directly attached during pre-mounting of the modular unit (e.g. welded), so that the modular unit can be connected directly with an actuating device such as a servomotor, a hydraulic or pneumatic actuator or the like for actuating the valve flap for opening or closing the flow opening into the flow channel.

The use of such a housing is, for example, as a so-called wastegate valve for an exhaust gas utilization turbine of a turbocharger or a turbocompound system. The use for realizing a blow-off valve for a compressor wheel in a turbocharger can also be considered. In accordance with an embodiment of the housing in accordance with the present invention it is provided that the blade wheel is an exhaust gas utilization turbine and/or a compressor wheel of an exhaust gas turbocharger.

BRIEF DESCRIPTION OF THE DRAWINGS

The above-mentioned and other features and advantages of this invention, and the manner of attaining them, will become more apparent and the invention will be better understood by reference to the following description of an embodiment of the invention taken in conjunction with the accompanying drawings, wherein:

FIG. 1 shows a schematic view of an exhaust gas turbocharger; and

FIG. 2 shows a configuration of the valve device of FIG. 1 configured in accordance with the present invention in the region of an exhaust gas utilization turbine.

Corresponding reference characters indicate corresponding parts throughout the several views. The exemplification set out herein illustrates one embodiment of the invention and such exemplification is not to be construed as limiting the scope of the invention in any manner.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to the drawings, and more particularly to FIG. 1, there is shown valve device 1 for an exhaust gas utilization turbine 2 based on an example of a turbocharger 3, which in the illustration of FIG. 1 is shown in a schematic view. Exhaust gas utilization turbine or turbine 2 of exhaust gas turbocharger 3 is connected in the known manner via a shaft 4 with a compressor or a compressor wheel 5. Hot exhaust gas flows through turbine 2 by way of the arrow indicated with reference numeral A, e.g. from the region of an internal combustion engine (not shown). The hot exhaust gas will expand in turbine 2 and then reaches the region of the ambient environment via the arrow designated with reference numeral a. The mechanical power obtained in this manner will be transmitted via shaft 4 directly onto compressor 5, which draws in fresh air from the ambient environment according to arrow b, compresses the same and supplies the air as combustion air according to arrow B to the internal combustion engine as mentioned above. This configuration is generally known from the state of the art. It will describe the function of valve device 1 on the basis of an example of exhaust gas turbocharger 3 in closer detail. A comparable configuration could also be applied to a turbocompound system, which also includes exhaust gas utilization turbine or turbine 2, which in this case does not drive compressor 5 via shaft 4 but typically a gearwheel or pinion. The power obtained in the region of turbine 2 via the pinion will then be used differently, e.g. providing supplementary power via a hydrodynamic coupling and a respective gear to the crankshaft. A further possibility for use lies in the region of compressor wheel 5. In this case too, air could be guided via valve device 1 in the bypass around compressor wheel 5 and could be blown off from the region of compressor wheel 5.

The valve device used for this purpose can be arranged like valve device 1 in accordance with the present invention, which will be described and explained below in closer detail by reference to the exhaust gas side. Both in the case of exhaust gas turbochargers 3 and also in turbocompound systems it may occur in specific operating situations that exhaust gas A is not guided through turbine 2, but needs to be guided entirely or typically partly about turbine 2. Valve device 1 is used for this purpose, which is also known as a relief valve, air recirculation valve, blow-off valve or wastegate valve. It connects the region of exhaust gas A flowing into turbine 2 with the region of the exhaust gas a leaving the region of turbine 2. Valve device 1 will be explained below in closer detail.

Referring now to FIG. 2, there is shown, valve device 1 which was schematically shown in FIG. 1 with its specific configuration. Valve device 1 consists of a valve flap 6 which can close off and open a flow opening 7 in housing wall 8 indicated here with the dashed line. Housing wall 8 encloses flow channel 9, e.g. the intake space for exhaust gas A into exhaust gas utilization turbine 2. Housing wall 8 is a part of a housing, which in this case, by way of example, is also part of the turbine housing. Valve device 1 consists of shaft 10 in addition to valve flap 6, which in the illustrated embodiment is arranged to be off-center of valve flap 6 and is connected with the flap via a connecting element 11. The connection can occur by welding valve flap 6 with connecting element 11 and/or shaft 10. Valve device 1 further includes a lever 12 at its end of shaft 10 which faces away from flow channel 9, which lever is also connected with shaft 10, e.g. welded together for example. Lever 12 is in connection with an actuating device 13 such as a servomotor, a hydraulic or pneumatic piston or the like. As a result of a rotating movement on lever 12, valve flap 6 can be pivoted from the closed position of flow opening 7 as shown in FIG. 2 about the axis of shaft 10 and will thereby release, depending on the pivoting angle, a continuously expanding cross-section of flow opening 7.

Shaft 10 is mounted in a bearing sleeve 14 in the illustrated embodiment in such a way that it can be twisted via lever 12 and actuating device 13 and that simultaneously the best possible sealing of flow channel 9 is ensured in the region between shaft 10 and bearing sleeve 14. Bearing sleeve 14 is introduced into a cover 15 (e.g. pressed into the same). Cover 15 sits in the mounted state in opening 16 in housing wall 8. Housing wall 8 and cover 15 are screwed together via thread 17. In addition to thread 17 in its region of the face surfaces facing flow channel 9, cover 15 further includes collar 19 in the region facing away from flow channel 9, which collar includes sealing surface 19 on its area facing the flow channel. Sealing surface 19, in combination with a corresponding sealing surface 20 which encloses opening 16, provides very good sealing between cover 15 and housing wall 8 in the mounted state.

Opening 16 includes an opening width D which corresponds to a circular diameter in the embodiment as shown in FIG. 2. In the case of other configurations of opening 16, e.g. in cover 15 which is flanged-mounted from the outside on housing wall 8, the opening could also have other shapes such as a rectangular shape, an oval shape or the like. In this case, opening width D would respectively mean the largest opening width. Opening width D must be chosen in any case in such a way that it is larger than the largest diameter of the smallest projected area of valve flap 6 and of the part of shaft 10 protruding in the mounted state into flow channel 9. The largest diameter of the smallest projected area is indicated by way of example by the diameter designated with reference numeral d in FIG. 2. Largest diameter a of the smallest projected area of the parts of valve device 1 protruding into flow channel 9 in the mounted state can be introduced (in the illustrated example by slight tilting) through larger opening 16 in the mounted state into flow channel 7. Complex mounting (e.g. complex welding of valve flap 6 with connecting element 11 and/or shaft 10 in the interior of flow channel 7) can be avoided. The configuration of valve device 1 with valve 6, connecting element 11, shaft 10, bearing sleeve 14, cover 15 and optionally lever 12 can therefore be pre-mounted outside of flow channel 9 and can be introduced through opening 16 into the flow channel and can be mounted by tightly screwing cover 15. The amount of mounting work is thereby minimized.

While this invention has been described with respect to at least one embodiment, the present invention can be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims.

Claims

1. A housing for a blade wheel of a turbo machine, comprising:

a flow channel enclosed by a wall of the housing;

a valve flap configured for selectively sealing and releasing a flow opening in said housing wall;

a shaft connected with said valve flap, said shaft configured for being guided through an opening in said housing wall to an outside of said flow channel, said housing wall opening having an opening width which is larger than a largest diameter of a smallest projected area of said valve flap and of a part of said shaft protruding into said flow channel in a mounted state; and

a cover through which said shaft extends, said housing wall opening being sealed by said cover in said mounted state.

2. The housing according to claim 1, wherein said cover is screwed together with said housing wall.

3. The housing according to claim 1, said cover having a round configuration and including at least partly on a face side of said cover a thread configured to cooperate with a reciprocal thread in a region of said housing wall opening.

4. The housing according to claim 3, said cover including said thread on said face side facing said flow channel and said cover further including a collar having at least one sealing surface on a side of said cover facing away from said flow channel.

5. The housing according to claim 4, wherein a rotational axis of said cover and a rotational axis of said shaft are arranged to be spaced from one another in a region of said cover.

6. The housing according to claim 5, said cover further including a bearing sleeve for said shaft.

7. The housing according to claim 6, wherein said bearing sleeve is arranged to be pressed together with said cover.

8. The housing according to claim 1, wherein said valve flap and said shaft are at least indirectly welded together.

9. The housing according to claim 8, wherein said shaft includes a lever on a side facing away from said valve flap.

10. The housing according to claim 1, wherein the blade wheel is arranged as at least one of an exhaust gas utilization turbine and a compressor wheel of an exhaust gas turbocharger.