The present situation of dynamic balancing of the ware of pressure boost

zhaoyanganshang

Ten years in near future, because of the unceasing development of auto industry with the pollution that people cause for its emission vent gas pay attention increasingly, for vent gas, emission control is asked increasingly strictly, so make the ware profession of pressure boost have gotten develop fast. From highland, go to plain, since outskirt goes to city, go to car gasoline engine from truck diesel engine, along with the development of time, nearly all automobiles the metropolis disposition turbine ware of pressure boost. So the turbine ware performance of pressure boost can nearly decide performance and the effect of entire engine badly good bad, and in which affect the one of most important factor of the turbine ware performance of pressure boost is working state key assembly dynamic balancing good spoil. It is explored, tried and improved continuously that people have gone on about the key assembly method of dynamic balancing, and have gotten huge advance.
     For the rigid ware of pressure boost( working rotational speed in critical rotational speed below, right now, turbine wheel shaft will not produce violent flexibility to warp ) combination balance, now, more popular method is: Besides compressed ship shell and turbine shell and installation bolt will own to spin element include the assemblies such as intermediate body and sealing ring together form core become always, put in the air drive for special purpose balancing machine on carry out two-sided balance, this kind of balancing machine will imitate the operating mode of the ware of pressure boost as far as possible , at the same time monitors the temperature in oil and rate of flow and the oil pressure in the bearing housing of oil pressure while measuring disequilibrium, in is higher than the speed that forms oil membrane measure ( the minimum point that forms oil membrane approximate in 1700 to 2500 RPMs, balanced rotational speed can usually select in 3000 to 5000 RPMs) the normal work of having guaranteed the floating bearing of oil pressure do not be damaged spoil and do not affect actual unbalanced result. Since being air drive take into disturb Xiao De much. And let the temperature of oil pressure and rate of flow and oil keep with operating mode have consistently also avoided also because of oil different tape into disturb. Balance qualified after, pack two housings to make factory.
    Practice result show , current balanced method can satisfy the needs of present market, balanced result is also accurate ( because of the ware work of pressure boost , the heat that turbine waste gas brings makes turbine be heated to expand, press impeller because of do merit give out heat is heated also to expand, so the disequilibrium of the ware operating condition of pressure boost can the result with low speed have difference , but deviation is very little ).
    For flexibility rotor( rotor less, axle is very thin, working rotational speed is more than critical rotational speed , when working , turbine wheel shaft can produce violent flexibility to warp ) with high speed key balance, since its operating mode is more complex, so far, there is still different viewpoint, thus have formed the balancing machine of different type. More consistent practice is:
    1) For it carry out single surface balance( because of rotational speed too high, now technical level, can not really accurate realization surface split ), theoretical foundation is in turbine end, when single produces , has carried out balance, after assembling have no any revolving element basically to add in this end, so, balanced condition should not have too big change, and compressor end has carried out balance though when single produces , but after assembling home the revolving elements such as liner and nut, can surely so need again balanced this end as disequilibrium produces influence.
    2) Adopt magnetic speed sensor detection rotational speed, the present working rotational speed of the small-sized ware of gasoline engine of pressure boost is above two-hundreds thousands RPM , can be responded in speed sensor for the rate of high frequency fairly promptly, have only magnetic speed sensor. But magnetic sensor is below to lie in phase angle can not quilt accurate get , so when carrying out unbalanced correction, it is fast accurate to can not revise. Reason is this sensor the change of being use for the strength of magnetic field the record rotational speed of rotor, so for the strength of magnetic field, it is strong to go to what kind of level, it is known that sensor begins to respond to have no way of, so for element after serving as magnetism, the summary of location of actual "0" degree angle becomes very important. Pass certain train , operator should grasp its specific location really basically. Though it is such, " actual 0 " the location of degree angle follow serve as the somewhat different and every time nut subtle discrepancy of material of magnetic skill every time metropolis have difference, basically angle error can be controled within 20 degrees.
     In recent years, to surmount angle error also have some units in explore continuously the speed measure system that attempts to use other types substitute magnetic speed system, for instance, American suddenly husband graceful company is having the only laser speed measure system and that our R&D makes that deploies on machine. Its biggest benefit lies in that this system can get unbalanced definite phase very accurately , has very little error. This system adopt laser count the method of compressor impeller blades, per process, a blade and light beam have been covered broken once and case history, for instance one has a kind of ware of pressure boost, the number of impeller blades is 12 slices, laser count one hundred and twenty thousands times , the ware actual rotational speed of pressure boost should be RPM of ten thousands, so pawn the ware actual rotational speed of pressure boost is RPM of fifty thousands , laser count frequency is six-hundreds thousands times. But because of the present limitation on technology, include transmiting line and signal to dispatch and the signal of PC board take over and calculation handling, biggest can only handle six-hundreds thousands times count ( now have again risen , can handle contract probably one million times count ), for 12 slices of wheel, if use usual way for each blade enumerated words, it is RPM of fifty thousands that only laser system can measure biggest rotational speed, this working rotational speed that is lower than the reality of the ware of pressure boost can not satisfy actual needs. A kind of general method is , since compressor impeller blades divides into main blade, with assign redundant civil servants to other jobs blade( usual, the high score of main blade flow out blade will happen high approximate 1/3) difference, if recording main blade only, for the reality that can be into time raising measured rotational speed. ( need to at the same time set in electronic-controlled system " scale down ", as soon as dividing into 2 or one to divide into 4 ). So as soon as coming for in the balanced option of rotational speed in a step critical rotational speed nearby ( RPM of eighty thousands use RPM of one hundred and sixty thousands ) machine , can satisfy basically, but this kind of practice, because of the actual decreasing of the quantity that reads to take blade, between blade, the increase of angle has increased the error of angle undoubtedly, though being more accurate than using magnetic speed sensor, or doing not read when taking all blades angle accurate. Along with user, need to measure system for present this kind of laser urgently for measuring the requirement of the unceasing raising of rotational speed to improve and perfect.
    The major different characteristic of each machine is:
      The way of driving for the ware of pressure boost difference, it is typical state with American suddenly husband graceful company's HXT-20.3 CB/HS and Germany g company's 110 MBRS is regular, suddenly husband graceful company is directly the part of clamping apparatus with the turbine shell of user, drive air imitate in the ware working state of pressure boost the drive in turbine cavity state, so the advantage of design is make key body the actual work and impact in turbine cavity flow path that borne as far as possible consistent, and need not go to redesign the drive of clamping apparatus housing the appearance that meets turbine. Shortcoming the requirement of rate of flow of being for angry source higher. For instance: To make JP-80 model wail , the ware( turbine external diameter is approximately 76 mm, the external diameter of compressor impeller is approximately 80 mm) rotational speed of pressure boost reaches RPM of eighty thousands, the rate of flow of compressor want 10 M3/min more. Pressure requirement is 0.65 Mpa to 0.7 Mpa, do not be very high; State Ke company's 110 MBRS have designed drive specially clamping apparatus, instead of adopt turbine shell the part as clamping apparatus, the drive of clamping apparatus realizes through a carefully hole spray nozzle, this thin hole with cavity have formed certain angle, and to prevent the huge noise that spray nozzle sends , it is greater that the shape design of thin hole become the two ends in hydromechanics that can reduce noise to start to talk, intermediate fine shape. The purpose of this is in reduce angry source and course as far as possible the condition of measuring demand take off , offer greater driving force as far as possible. But the pressure of machine for angry source has relatively higher requirement, want 0.65 Mpa to at the same time compare difficult realization to 0.8 Mpa for the requirement of big rotor high rotational speed probably want also make the JP-80 model ware of pressure boost turn RPM of eighty thousands, this machine realizes comparison, is difficult.
   Compare two different technologies, the author thinks that the design of the former is more superior, one is in rotor identical can reach higher rotational speed; 2 is machine work the operating mode of the more near ware of pressure boost. And it is that single point gets force with the drive of spray nozzle, with the ware of pressure boost pack the air driving force that gets on engine difference, under the high rotational speed of flexibility rotor, the deformed condition of key body and axle is complex , is hard to say very much as the vibration of reality warps , do not cause to disturb. This lets one produce doubt for the accurate level of the result that shows.
    The measure unit adopted difference: What the supplier of majority adopt is that acceleration g ( mm/s2 ) or vibration speed g ' ( mm/s ), and can change between each other. Also have very few adopt unbalanced g-mm is unit. No matter with what kind unit, eventually, purpose is to reflect true state better. The author more trend in use vibration speed g ' ( mm/s ), what reason is that the engine manufacturer owned cares for is that the ware of pressure boost installation the vibration condition on engine, their most direct acceptance standard should be vibration whether exceed to mark, it is amount that they not definitely understand acceleration g very much or is disequilibrium is how many g-mm , the ware of pressure boost is acceptable. If unit will consistently offer the most strong reference for customer undoubtedly, basis.
    Certainly, the with high speed key machine of dynamic balancing of every manufacturer is being very various to have its each characteristic , for example G. T. me. Company ( the Japanese subsidiary who unites letter ) have adopted completely identical magnetic speed and phase identification system in semi-automatic correction balancing machine to avoid the error of magnetic speed system in correction; American suddenly husband graceful company controls system in measuring course with the servo speed of closed circuit, here for not 11 acts.
    But for me see , include owning these machines, still have some places that deserve to pay attention and need to perfect , for example:
    Because of drive air is cold , and operating mode waste gas is heat and temperature is difference high very much, so rotor in balancing machine on it and the change of hot expansion and centroid in engine on operation can have; And the mixture of oil gas the form that explodes in cylinder promote engine operation, waste gas produce with emission change multiterminal, the motive force with the air of measure balanced space-time is also possible and different.
    Because of want drive rotor go to high speed, if incorrect compressor impeller end is handled , compressor impeller certainly will make merit, obstruction rotational speed rises. It should be held that so, nearly, all manufacturers have adopted to use the cover of seal ring, when acceleration spins , makes compressor impeller end form approximate vacuum, so as soon as coming , can blow rotational speed to go up and have gone , and since being approximate vacuum, on the one hand, still have partial airs, compressor impeller can still make merit give out heat; On the other hand, can again produce the phenomenon " fall to inhale" , can inhale the oil in bearing cavity along seal ring to compressor impeller end. Can affect as sealing up to produce, may still occur oil the combustion " emit smoke" phenomenon.
     Believe that can get improvement along with technical advance, with top surface , make machine more perfect.

suzuki

关于增压器零件动态平衡的现状与未来十年展望

随着汽车行业的持续发展，增压器作为引擎的重要部件日益受到关注。当前，增压器零件的动态平衡技术已逐渐成熟，但仍面临挑战。未来十年，随着环保意识的提高，对于排放控制的要求也日益严格。因此，增压器排放的尾气污染问题成为人们关注的焦点。对此，业界正在积极研发新技术和新材料，以提升增压器零件的动态平衡性能，同时降低排放污染。相信随着技术进步，增压器零件的动态平衡问题将得到更好的解决。