Shaft seal
Technical field
The present invention and the field that relates to fluid machinery and utilize in particular the exhaust turbine supercharger that the exhaust of internal-combustion engine is loaded.
The present invention relates to a kind of shaft seal of such fluid machinery.
Background technique
Use exhaust turbine supercharger according to standard at present in order to promote power of IC engine, it is with the turbo machine in the outlet pipe of internal-combustion engine and with the compressor before being positioned at internal-combustion engine, and this compressor is connected via common axle with turbo machine.Utilize and carry out supercharging by means of exhaust turbine supercharger combustion motor, the loading in cylinder and therefore fuel mixture promote and obtain thus the significant power ascension for motor.Optionally can change into electric energy or mechanical energy by means of power turbine in connection with the energy in I. C. engine exhaust.Generator or mechanical load are connected to turbine shaft place by compressor alternative at this as in exhaust turbine supercharger situation.
Exhaust turbine supercharger sample plot is by rotor (comprising axle, compressor impeller and turbine wheel), assemble for the supporting of axle, the casing component of water conservancy diversion (compressor case or turbo machine case) and supporting member case.
Due to the high pressure process in the flow region of turbine pusher side and compressor side, should utilize suitable seal concept to seal the axle of exhaust turbine supercharger with respect to the cavity of supporting member case.Interior pressure in the cavity of supporting member case is conventionally corresponding with barometric pressure.But gas pressure in the flow channel of compressor side or turbine pusher side depends on the current operating point of exhaust turbine supercharger and exceed the pressure in the cavity of supporting member case in most of operating point.But also can consider in some cases negative pressure, for example, in operation at part load or in state of rest.
By the shaft seal of the turbine pusher side of file DE 20 25 125 known exhaust turbine superchargers, it assembles by the simple collection chamber on the turbine pusher side at radial bearing and with the piston ring of the seal action between axle and supporting member case.The supporting member machine oil of axially discharging from radial bearing is sprayed onto the shaft shoulder of outside skew and rotation and is thrown in collection chamber by centrifugal force.And then the supporting member machine oil of so throwing away followed gravity and in collection chamber, flowed downward and again turn back in the lubricated oil circulation of supporting member.
Leak in the cavity of supporting member housing and use according to standard the piston ring of being made by for example grey cast iron of metal by the impeller back space (Radr ü ckraum) of turbo machine from flow channel in order to reduce gas.In bearing housing, the piston ring in stress is clamped in the radial slot with axial stop shoulder.As the mating member of piston ring, the axle of rotation is provided with radial slot, and wherein piston ring axially blocks and radially cover this groove in this groove.Due to the pressure reduction between exhaust pressure and the pressure in supporting member case inside, in the direction of existing pressure gradient, within groove, axially push piston ring to backstop.Locate this piston ring break-in (einschleifen) and all with respect to exhaust stream sealed bearing case by piston ring axially mounting at one of groove internal surface.Also can use two or more piston ring in order to improve sealing effect, as for example disclosed in file CH 661 964A5, US 3 180 568, US 4 196 910 or EP 1 860 299.In these files, show how to use sealing air (Sperrluft) or to be exitted with respect to hot exhaust lift-off seal effect and can stop thus exhaust gas leakage completely in supporting member case in the space between two piston rings by additional.
By the shaft seal of the turbine pusher side of the known exhaust turbine supercharger of file DE 37 37 932 A1, oil is discharged between supporting portion and two piston rings from radial bearing therein.In this case improve oil seal and substitute the simple axially shaft shoulder and use additional disc (Schleuderscheibe).Can significantly reduce thus the amount of the undesirable supporting member oil clashing in piston ring groove region.In the oil extraction between radial bearing and the piston ring of vicinity according to realization in the shaft seal of file US 4 268 229 and DE 30 21 349, wherein oil extraction portion is always formed by chamber similarly.Additionally the cavity between two piston rings is connected and ventilates to atmospheric environmental pressure with the cavity of supporting member case by means of additional connecting passage.Stop thus pressure reduction synthetic on left piston ring, to make piston ring mainly bear sealing oil and the function of non-tight hot gas.Therefore only right piston ring is born the sealing between the flow channel under pressure condition and supporting member case cavity.Therefore obtain two kinds of discharge portions for Medium Oil (being derived from radial bearing) and exhaust (being derived from flow channel) of separating by this constructional variant, wherein discharge portion is separated by piston ring.The lubricant oil of discharging from radial bearing may (unter Umst nden) be axially sprayed onto the piston ring region of gas seal and in least favourable situation, floods whole piston rings.Conventionally the gas pressure in the flow channel of compressor or turbo machine is greater than the gas pressure in the supporting member case inside of turbosupercharger.Therefore positive differential pressure (gas pressure in flow channel is greater than the gas pressure in supporting member case cavity) causes, and the gas leakage of appearance is blown over (durchbl st) piston ring packing part and the supporting member oil being by mistake penetrated in piston area is carried in the collection chamber that turns back to supporting member case again.
The seal arrangement of the lubricated supporting for rotor shaft of describing in file DE 10 2,004 055 429 B3 is attempted the above-mentioned situation of opposing, and sealing device seals the supporting member case of exhaust turbine supercharger in the axial direction with respect to the oiling agent of supply.On rotor shaft, arrange with the first Sealing of gap, labyrinth or piston ring form with the second Sealing of the form in narrow gap or labyrinth, it is surrounding the oil drain passage that the periphery around rotor shaft extends circlewise between itself, the axle side oil-discharge trough that this oil drain passage is arranged by means of case side oil-discharge trough with in axial same position builds.In oil drain passage, be provided with at rotor shaft and utilize in the radial direction end freely to protrude into the annular sealing bridge part in annular oil drain passage, it is bar acting in the axial direction of the oiling agent for being penetrated into oil drain passage and the gap that radially covers the second Sealing.
In the shaft sealing concept of all descriptions, there is in some cases such risk, be that hot gas leaks by piston ring packing part from the impeller back space of exhaust steam turbine, and in piston ring region and oil-discharge trough residual supporting member combustion of oil in-situ and cause thus the coking of shaft seal and the loss of associated.Coking risk is along with the delivery temperature rising with by the leakage rate of lifting and cooling the increasing of parts of bad luck of piston ring.Therefore the cooling seal part of active is important for the security of operation of shaft seal.
File EP2375000 discloses the shaft seal between supporting member case and the axle of mobile handling machinery, it comprises the Sealing of impeller side and the Sealing of supporting member side, wherein between the Sealing of impeller side and the Sealing of supporting member side, oil-discharging cavity is set, this oil-discharging cavity is limited by the 3rd Sealing between supporting member case and axle.Between the 3rd Sealing and the Sealing of impeller side, arrange that gas leaves chamber, wherein this structure is cooled on one's own initiative by least one nozzle opening in the region of oil extraction ditch, can stop thus the coking of shaft seal.The 3rd Sealing separates the oil that is derived from oil-discharging cavity at this with the gas that is derived from gas and leaves chamber.The part of the axle side of Sealing forms by the sleeve on axle (Aufsatz) alternatively.
Summary of the invention
The object of the invention is, provide a kind of improved shaft seal of the axle supporting of fluid machinery in supporting member case, therein by can make the coking risk minimization of piston ring packing part from the improved heat output of Sealing part (Dichtungspartie).
For (being located between the impeller back space of impeller of cavity in supporting member case and fluid machinery according to the shaft seal that is bearing in the axle in supporting member case of fluid machinery of the present invention, with the sleeve on axle, be included in the Sealing of impeller side of the form with at least one piston ring between supporting member case and sleeve and the Sealing of the supporting member side of the form with seal clearance between supporting member case and sleeve, wherein between the Sealing of impeller side and the Sealing of supporting member side, oil-discharging cavity is set, wherein oil-discharging cavity is limited by the 3rd Sealing of the form with seal clearance between supporting member case and sleeve, and between the 3rd Sealing and the Sealing of impeller side, be furnished with gas and leave chamber, its middle sleeve has such profile, this profile and supporting member case form oil-discharging cavity and gas leaves chamber and comprises that at least one is for holding the groove of at least one piston ring jointly), according to the present invention, sleeve has two axially spaced-aparts towards axle, the supporting zone of power upwards can be transmitted in footpath, two supporting zones are so constructed, be that it makes transmission power diametrically become possibility, wherein that supporting zone that is arranged in impeller side in two supporting zones is arranged in the region of at least one piston ring of the Sealing of impeller side on axially.
Two short bearing portions (Sitz) by sleeve (shaft sealing lining) respective end place replace long continuous bearing portion can reduce the surface of contact between axle and bearing sleeve and therefore reduce by impeller and input by the heat of axle, wherein advantageously at two axially spaced-aparts of the sleeve on axle, radially can transmit between the supporting zone of power structure with the cavity of air filling.
The distortion causing due to centrifugal force can be kept to less by the bearing portion that directly arranges impeller side in piston ring region.
Alternatively, footpath is upwards incorporated into oil extraction ditch and in supporting member case and in supporting member case, is furnished with at least one oil spurts hole outside oil-discharging cavity, utilize this oil spurts hole to load oil to oil extraction ditch, wherein oil extraction ditch extends in the axial direction until at least one piston ring of impeller side Sealing.
Heat in support region can directly radially be exported via lubricant oil compared with great share outside piston ring thus.
Advantageously oil extraction ditch is configured to the Sealing towards impeller side in the axial direction and tilts towards axis, thereby is directed to oil in oil extraction ditch because gravity flows towards impeller side in the axial direction in supporting member side.
The piston ring of impeller side Sealing is directly loaded cooling medium (sealing air) alternatively.Stop thus hot gas to penetrate into supported clearance from impeller impeller back space.
Sleeve (shaft sealing lining) can have been expanded alternatively to the function of torsional vibration damper, this can realize by light strong the pressing of pressing and locating in the bearing portion of impeller side at the place of bearing portion in supporting member side.Wherein the pressing and must correspondingly with vibration damping demand design of place of fore bearing portion.For this reason additionally or substitute can in bearing portion, introduce for example polytetrafluoroethylene band (Teflonband) of friction element, can in the time of torsional vibration, make full use of thus the relative movement at axle place, for in order further to promote decay constant (D mpfungsmass).
Alternatively, such region of supporting member case (being that it is a part for shaft seal constructed according to the invention) can be configured to embedded piece.Embedded piece can easily be replaced or for example for cleaning purpose temporarily takes apart from supporting member case in the time of the wearing and tearing that cause due to operation.
In addition can select the material with high as far as possible heat-conducting property as the material for this embedded piece.
Accompanying drawing explanation
Next at length set forth according to shaft seal of the present invention by means of drawing.Wherein:
Fig. 1 shows the diagram of dissecing according to the part of the exhaust turbine supercharger with radial compressor and axial turbine of prior art,
Fig. 2 shows through according to the cross section along axle guiding of the shaft seal of the turbine pusher side of the exhaust turbine supercharger of prior art,
Fig. 3 shows through according to the cross section along axle guiding of the shaft seal of the turbine pusher side of the exhaust turbine supercharger with the sleeve on axle of prior art,
Fig. 4 shows the cross section along axle guiding of passing through according to the shaft seal of the turbine pusher side of exhaust turbine supercharger of the present invention.
List of numerals
10 turbo machines
11 turbine wheels
12 suction ports
13 relief openings
The impeller back space of 15 impellers
20 axles
21,22 sealing bridge parts
30 supporting member cases
The embedded piece of 31 supporting member cases
32 sealing plates
33 sealing bridge parts
34 radial bearings
The delivery line of 35 cooling mediums (sealing air)
39 cap shape shielding parts
41,42 piston rings
43,44 radial seal gaps
50 cavitys in supporting member case
51,52 oil extraction ditches
53 oil-discharging cavities
54 oil drain passages
55 gases leave chamber
56 exhaust passages
60 oily passages
61 oil spurts holes
62 supporting member flanges
63 interior profiles
70 compressors
71 compressor impellers
72 suction ports
81 with the co-rotational sleeve of axle
821,822 bearing support part
83 axial stop
85 cavitys
86 damping elements.
Embodiment
Fig. 1 shows according to the exhaust turbine supercharger of prior art, and it is with radial compressor 70 and axial turbine 10.The case part of the exhaust turbine supercharger of drawing is dissectd and is illustrated, in order to see the rotor with compressor impeller 71, axle 20 and turbine wheel 11.Air from suction port 72 to compressor impeller 71 guides with thick arrow explanation.Be directed to relief opening 13 by suction port 12 via turbine wheel 11 at turbine pusher side thermal exhaust.Axle 20 is rotatably mounted in supporting member case 30, conventionally by means of two radial supports and at least one axially mounting.
Fig. 2 shows according to the shaft seal of prior art, and it separates the cavity in supporting member case 50 and impeller back space 15 of turbine wheel 11.Comprise embedded piece 31 (seal cartridge) in the region of shaft seal at this supporting member case, it is embodied as independently member.Embedded piece 31 is configured to annular, and comprises radially go up the injection oil of outside oil extraction ditch 52 for radially outwards throwing away and laterally send (abgeben) from radial bearing 34.Directly or indirectly to spray oily splash (bespritzen) embedded piece and cooling embedded piece on one's own initiative thus.Direct on member to be cooled spraying oil by oil spurts hole 61.Realize and spray oily supply by the oily passage 60 in supporting member housing 30.So implement and orientation in oil spurts hole 61, sprays oil profile 63 in collision in the region of supporting member housing 30, and the embedded piece of getting wet in the region of oil extraction ditch 52.By spraying oil and the oil from supporting member 34 and oil extraction ditch 51, cooling embedded piece and be arranged in piston ring, Sealing and the discharge side of embedded piece all sidedly, and stoped to a great extent coking.In order to improve the cooling effect on piston ring and discharge side, preferably manufacture embedded piece 31 by the material of the thermal conduction characteristic with high as far as possible.Limit oil extraction ditch 52 by radially extending the sealing plate 32 of (ausziehen) in the axial direction, sealing plate 32 self by the oil cooling in discharge route 51 but on the other hand.In addition, embedded piece comprises that reentrant part is for holding the piston ring 41 and 42 of two tandem arrangement.In addition, embedded piece comprises oil-discharging cavity 53, leaves chamber 55 and sealing bridge part 33 for the independently gas of the Leakage Gas from two piston rings 41 and 42 being radially arranged in inner region, and it is separate that oil-discharging cavity 53 and gas are left chamber 55 by sealing bridge part 33.
Oil extraction ditch 51 between radial bearing 34 and sealing plate 32 forms the first main discharge route of the supporting member oil leaving from radial bearing.Sealing plate 32 and radially first bridge part 21 relative and that put of axle 20 form the first seal clearance 43 radially, due to sealing gap 43, the infiltration of supporting member oil from oil extraction ditch 51 to oil-discharging cavity 53 are minimized.The arbor wheel exterior feature of the rotation of oil-discharging cavity 53 is provided with radially inwardly (versetzt) drain tank of dislocation, obtains thus spraying seamed edge (Abspritzkante) in the left side of this groove and two of right side within oil-discharging cavity 53.Due to gravity, the oil passing through in outside region radially that groove in embedded piece 31 forms that is thrown to oil-discharging cavity 53 by spraying seamed edge flows downward along the profile of embedded piece 31 within oil-discharging cavity 53.In order supporting member oil to be led back to from oil-discharging cavity 53 in the lubricated oil circulation of supporting member, oil-discharging cavity 53 has at least one oil drain passage 54 in the region of bottom.
The embedded piece 31 of shaft seal constructed according to the invention is by being arranged in the gas on oil-discharging cavity 53 sides and leaving chamber 55 and outstanding, by around sealing bridge part 33 gas left to chamber 55 separate with oil-discharging cavity 53.Be configured to annular gas and leave chamber 55 for collecting the hot gas that flows through piston ring 41 and 42.Sealing bridge part 33 and radially second bridge part 22 relative and that put of axle 20 form the second seal clearance 44 radially.According to the present invention, seal clearance 44 is separated two media (by the oil from oil-discharging cavity 53 and the gas that leaves chamber 55 from gas) clearly.On the other hand, the independently exhaust passage 56 separating within embedded piece 31 and with oil drain passage 54 by least one, transfers to the gas of catching in gas outlet chamber 55 in the common volume (Volumen) of the cavity 50 in supporting member housing.By the separation targetedly of two discharge portions, should stop two media to mix in the region of oil-discharging cavity 53, and reduce thus the coking danger in seal assembly (Dichtverbund).In addition, by large oil extraction ditch 51 and the first Sealing 43, the major part of the supporting member oil leaving from radial bearing 34 is outwards drawn, and keep supporting member oil away from piston ring part by oil extraction ditch 52.
Fig. 3 shows that the arbor wheel exterior feature of the rotation of turbo machine is therein implemented by hood-like sleeve 81 in the region of shaft seal according to the shaft seal of Fig. 2 (being only provided with the feature with reference character of adding with respect to Fig. 2 for the purpose of better observing).Sleeve 81 at this hot charging to the long bearing portion 82 on axle and the seamed edge of constructing on axle for sleeve 81 as axial stop 83.
Fig. 4 diagram according to the shaft seal of Fig. 3 according to improvement of the present invention.So construct in this supporting member case, sleeve and bearing support part, make to maximize and minimize to the heat input of axle via supporting zone via oil cooled heat output.Sleeve advantageously can be manufactured by the material of good heat conductive.
According to the present invention, sleeve 81 utilizes abutting on axle 20 of two short bearing portions.The cavity 85 that is filled with gas extends between the bearing portion 821 of supporting member side and the bearing portion 822 of impeller side, and this cavity 85 is as the isolation layer between sleeve and axle.Sleeve utilizes axial stop 83 to abut in axle place in the axial direction.Shown in form of implementation ring-shaped sleeve 81 there are four and be positioned at outside groove.The groove of two supporting member sides and corresponding groove in the embedded piece 31 of supporting member case be common form above-described, leave chamber 55 by the known oil-discharging cavity 53 of prior art and gas.The groove of two impeller side of sleeve is used for holding two piston rings 41 and 42, and it forms the sealing of the impeller side of shaft seal.Two piston rings abut in embedded piece 31 places of supporting member case.The embedded piece 31 of supporting member case has oil extraction ditch 52, and it makes lubricant oil be transported to radially and become possibility in the region outside sleeve.According to the present invention, oil extraction ditch extends in the axial direction until at least one piston ring 41 and 42, thereby can guarantee to come by means of lubricant oil the Sealing of cooling wheel side.Oil extraction ditch 52 is towards the inclination of axle, makes to be incorporated into lubricant oil in oil extraction ditch because gravity can flow towards impeller side along oil extraction ditch.Supporting member case 30 and embedded piece 31 are so constructed at this, are provided for the discharge possibility of lubricant oil in the region that is arranged in bottom based on gravity.The dark arrow that oil flow utilization is thin in the drawings shows.Advantageously be derived from supporting member region for cooling shaft Sealing uses, in concrete example, be derived from the lubricant oil of the delivery line of radial bearing.
In described form of implementation, shaft seal has sealing air supply department.Air of the compression showing with little white arrow at this is directed to via the sealing air passage supporting member case 30 by compressor side (or mode) to carry from outside in the supported clearance in the impeller side of piston ring packing part of impeller side.Sealing air is used herein on the one hand directly coolant seal part, stops on the other hand, and hot gas may be penetrated into seal clearance from the impeller back space 15 of impeller.
Sleeve (shaft sealing lining) can have been expanded alternatively to the function of torsional vibration damper, this can be pressed and be realized in strong the pressing at 822 places of bearing portion of impeller side by 821 places of bearing portion by supporting member side light.That wherein locates in the bearing portion of supporting member side presses and must correspondingly with vibration damping demand design.Additionally or alternatively can in bearing portion, introduce for example polytetrafluoroethylene band of friction element 86 of vibration damping for this reason.Can in the time of torsional vibration, make full use of thus the relative movement at axle place, with in order further to promote decay constant.
Can without embedded piece independently in the situation that, supporting member case be configured in shaft seal region constructed according to the invention alternatively.Corresponding groove, sealing plate and sealing bridge part are introduced directly in supporting member case in this case.The form of implementation with independent embedded piece 31 of describing in detail with respect to the modification without independent embedded piece 31 of one-piece construction has advantages of such, for the object embedded piece 31 of coolant seal part part for example, by for example, material manufacture with thermal conductive resin (Ck45) and be therefore independent of used supporting member case material (GGG-40).In addition embedded piece can easily be replaced or for example for cleaning purpose can temporarily take apart from supporting member case in the time of the wearing and tearing that cause due to operation.
Shown in form of implementation shaft seal comprise two piston rings 41 and 42.Alternatively a piston ring also can be only set or it can arrange other piston ring in this region or at other position of shaft seal.
Form of implementation shown and that describe in detail shows the shaft seal on turbine pusher side or the power turbine of exhaust turbine supercharger constructed according to the invention.Shaft seal constructed according to the invention can certainly use in any other fluid machinery.