US3158039A - Dynamic balancing system for rotating structures - Google Patents

Dynamic balancing system for rotating structures Download PDF

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Publication number
US3158039A
US3158039A US174160A US17416062A US3158039A US 3158039 A US3158039 A US 3158039A US 174160 A US174160 A US 174160A US 17416062 A US17416062 A US 17416062A US 3158039 A US3158039 A US 3158039A
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United States
Prior art keywords
shaft
chambers
raceway
balancing
assembly
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Expired - Lifetime
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US174160A
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English (en)
Inventor
Favrot Paul
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LANDIS GENDRON SA
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LANDIS GENDRON SA
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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C32/00—Bearings not otherwise provided for
    • F16C32/06—Bearings not otherwise provided for with moving member supported by a fluid cushion formed, at least to a large extent, otherwise than by movement of the shaft, e.g. hydrostatic air-cushion bearings
    • F16C32/0629—Bearings not otherwise provided for with moving member supported by a fluid cushion formed, at least to a large extent, otherwise than by movement of the shaft, e.g. hydrostatic air-cushion bearings supported by a liquid cushion, e.g. oil cushion
    • F16C32/064—Bearings not otherwise provided for with moving member supported by a fluid cushion formed, at least to a large extent, otherwise than by movement of the shaft, e.g. hydrostatic air-cushion bearings supported by a liquid cushion, e.g. oil cushion the liquid being supplied under pressure
    • F16C32/0651—Details of the bearing area per se
    • F16C32/0659—Details of the bearing area per se of pockets or grooves
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
    • B24B41/00—Component parts such as frames, beds, carriages, headstocks
    • B24B41/04—Headstocks; Working-spindles; Features relating thereto
    • B24B41/042—Balancing mechanisms
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16F—SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
    • F16F15/00—Suppression of vibrations in systems; Means or arrangements for avoiding or reducing out-of-balance forces, e.g. due to motion
    • F16F15/32—Correcting- or balancing-weights or equivalent means for balancing rotating bodies, e.g. vehicle wheels
    • F16F15/36—Correcting- or balancing-weights or equivalent means for balancing rotating bodies, e.g. vehicle wheels operating automatically, i.e. where, for a given amount of imbalance, there is movement of masses until balance is achieved
    • F16F15/363—Correcting- or balancing-weights or equivalent means for balancing rotating bodies, e.g. vehicle wheels operating automatically, i.e. where, for a given amount of imbalance, there is movement of masses until balance is achieved using rolling bodies, e.g. balls free to move in a circumferential direction
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
    • G01M1/00—Testing static or dynamic balance of machines or structures
    • G01M1/30—Compensating imbalance
    • G01M1/36—Compensating imbalance by adjusting position of masses built-in the body to be tested
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T74/00—Machine element or mechanism
    • Y10T74/21—Elements
    • Y10T74/2121—Flywheel, motion smoothing-type
    • Y10T74/2122—Flywheel, motion smoothing-type with fluid balancing means
    • Y10T74/2123—Flywheel, motion smoothing-type with fluid balancing means and pressure compensation

Definitions

  • This invention relates to .systems for dynamically balancing rotating mechanical members, a problem that arises in connection with any type of high-speed rotary machinery. Taking as an .example the case of a highspeed revolving grinding wheel in a grinding or rectifying machine, the center of gravity of the wheel is liable to shift slightly off-center with time because of irregularities in wear coupled with minor non-unformities in the density of vthe wheel material, and/or in the distribution of moisture in the pores of the wheel. At the high ⁇ :angular speeds involved, even very small offthe center of gravity can result in the of large centrifugal forces liable to cause development heavy rea breakdown of the grinding wheel or other volving part concerned.
  • the 3 passages above are connected respectively to 3 ducts provided in the shaft and opening radially in the oil lm of the bearing, each of the pressure receiving openings being at 120 in respect to any one of the other openings.
  • the pressure differentials created in the oil film of the bearing by an unbalance are transmitted to the corresponding chamber, so that the movable masses are supposed to move 'in respect to each other so as to compensate the unbalancing effect.
  • a dynamic balancing system of the type above defined, a plurality of circumferentially spaced recesses formed in the periphery of the rotating shaft within its bearing said recesses being equal in number to the plurality of movable elements, passage means connecting each of said recesses with a corresponding one of .the balancing chambers, and means for supplying fluid .under pressure to veach recess and, consequently, to the corresponding 'interconnected balancing chamber.
  • a body of iiuid under pressure is interposed between said shaft and bearing, in the zone including said recesses, said body supporting at least partially said shaft in the manner rknown in liuid type bearings.
  • a bearing of the uid type combined with a balancing system permits to solve the diiiicult problem of feeding the annular recess practically, because it permits ⁇ both to vary in the desired manner the output vof the iiuid and the ⁇ value of the pressure differentials supplying the compensating signal, this type of bearing being unaffected when mechanical clearances are relatively high, which again is due to the fact that the shaft is completely floating in the iluid under pressure without .ever contacting ,the stationary mechanical parts.
  • vabutments are provided inside the annular recess to positively limit the displacement .of each compensating mass so that no separation means are necessary and a continuous annular recess takes place of the known arcuate chambers of a reduced length. It is also an object to provide an improved .construction o'f the movable balancing elements, which will ensure their smooth, free-floating, self-lubricated displacement along the continuous annular raceway in sealing engagement with the walls thereof, while rendering the manufacture of such elements simple and inexpensive.
  • FIG. l is a view of the improved apparatus in axial section
  • FIGS. 2 and 3 are cross sectional views respectively on the planes designated Il--ll Aand Ill- III in FIG. l.
  • annular member 1 shown as a cylindrical member is secured on a shaft 2 for rotation therewith.
  • Shaft 2 is rotatably mounted within a bore in a smooth bea-ring member 3 by way of a fluid bearing later described.
  • the shaft is here shown as being horizontal and the annular part 1 is mounted on an end of the shaft by way of a rigid assembly generally designated 4 and providing a housing within it Vfor the active portion of a dynamic balancing or compensating system presently described.
  • the assembly 4 comprises a pair of parallel spaced iianges 5 and 6 and a spacer ring 7 positioned between said flanges adjacent the radially outer surfaces thereof, said fianges and ring being suitably secured by means not shown within the central bore of annular member 1.
  • the assembly 4 is held in firm engagement against a shoulder il provided on shaft 2 by means such as a retainer nut 9 screwed on a threaded end part of the shaft.
  • each roller is just slightly smaller, e.g. by an amount of the order of 0.02 mm., than the difference in radius between ring 7 and shaft 2, and the length of each roller is just slightly smaller, say
  • the three rollers 11, 12, 13 define, in the continuous raceway, three compensating or balancing chambers 17, 18, 19.
  • the volumes of the three chambers are variable with the relative positions of the three rollers round the raceway.
  • means such as stops 51, 52, 53 projecting from the inner periphery of ring 7 at 120 degree spacings therearound, are provided for positively limiting the arcuate displacements of the three rollers to arcs such that the positions of the three chambers cannot wander unrestrainedly around the circumference of the shaft for reasons that will later appear.
  • each roller is interconnected by a number of axial passages, herein shown as a central passage 57 and four passages 58 spaced around the circumference of the roller and connecting at their opposite ends with annular grooves 59 formed in the roller end faces.
  • arcuate sustentation recesses 21, 22, 23 are of equal arcuate extent and are separated by equal arcuate distances.
  • fluid under pressure is maintained in the three recesses through means presentlydescribed.
  • Fluid flowing out of the recesses is collected by three longitudinal grooves 31, 32, 33 formed in the periphery of shaft 2 intermediate the recesses as shown in FIG. 3, said grooves connecting at their opposite ends with a pair of circumferential channels 35 and 36 formed in the shaft beyond the ends of the recesses (see FIG. 1).
  • the channels 3S, 36 communicate with registering channels 37, 3S formed in the inner periphery of sleeve 3 from which the fluid is returned to a sump or exhaust.
  • Means are provided for supplying uid under pressure ⁇ in parallel to each of the balancing chambers 17, 18, 19 and a related one of the shaft recesses 21, 22, 23.
  • a radial inlet passage 41 formed in the bearing sleeve 3 is adapted to be externally connected with a pressure source of said fluid, e.g. oil.
  • the passage 41 delivers into a circumferential inlet manifold channel 42 formed in the inner surface of sleeve 3.
  • Two or more radial passages 43 formed in shaft 2 connect the circumferential inlet manifold 42 with an axial bore 44 formed through the shaft 2.
  • the outer end of bore 44 is adapted to be sealed with a screw plug as indicated on the left of FIG. 1.
  • each of the passages 26 is connected near one end by way of a radial port 46 with the axial passage 44. Further, each passage 26 is connected'by a radial passage 25 with a related point of the continuous annular raceway, the three passages 25 being angularly equispaced and being positioned opposite to the respective stops 51, 52, 53 (see FIG. 2) so as to deliver into each of the three balancing chambers 17, 13, 19, respectively regardless ofthe positions of the rollers. Moreover, each longitudinal passage 26 connects by another radial passage 27 with the center of a related one of the recesses 21, 22, 23.
  • an insert 47 interposed in each longitudinal passage 26 between its connection 46 with the central bore 44 and its connection 25 with the raceway is an insert 47 providing a calibrated restricted orifice.
  • another calibrated insert 30 is shown as inserted into each of the passages 25.
  • the system operates as follows. Assuming the rotating assembly comprising shaft 2 and the annular part 1 (which be it noted may stand for any complex revolving assembly) is perfectly centered dynamically, i.e. its center of gravity is positioned accurately on the rotational axis of shaft 2, then the thickness of the fluid film between the adjacent surfaces of shaft 2 and bearing sleeve 3 is continually uniform all around the circumference of the shaft throughout each shaft revolution (disregarding for the time being the minor and constant effect of gravity present when the rotational axis is horizontal as here shown). The uid pressure in all three recesses 21, 22, 23 and hence in all three balancing chambers 17, 13, 19 con nected thereto, is hence continually the same. Because of the equal pressures in chambers 17, 18, 19, the three rollers 11, 12, 13 assume equi-angular positions along the raceway as shown'.
  • an unbalance mass is present at some point in the revolving assembly, due to some uncontrollable cause.
  • Such an unbalance mass has here been symbolically indicated as a small additional weight B attached to a point of annular part 1, specifically adjacent the stop 51 marking the center of balancing chamber 17.
  • the unbalance will generate a centrifugal force which throughout each revolution tends to press the recess 21 of the shaft into tight engagement with the inner surface of bearing 3, so that the fluid film thickness is reduced in the corresponding shaft area and the pressure in recess 21 becomes greater while the pressure in the other two recesses Z2, 23 grows correspondingly lower.
  • rollers 12, 13 towards roller 11 creates an unbalance reverse from that produced by the mass B, and when the roller displacement has been sufficient to offset the initial unbalance so that the resulting centrifugal force is zero and the shaft is revolving in a centered condition in its bearing, the pressures in the three shaft recesses 21, 22, 23 and hence in the three chambers 17, 18, 19 are equalized so that the rollers 12 and 13 remain relatively stationary in their displaced positions. This condition will last so long as the initial unbalance remains unchanged in amount and in phase (or angular position).
  • the ⁇ "system described accomplishes a permanent and vcontinual compensation of a dynamic unbalance with very rapid response, a result attributable in part -to the large ow ⁇ of fluid and to the high pressure under which the fluid is delivered in a iiuid bearing, as well as to the direct supply of fluid in parallel to each shaft recess and balancing chamber, 'by way of a common restricted orifice 47.
  • This parallel supply of fluid is found to result in substantially improved performance characteristics over what is obtained with a serial supply of iluid through the fluid film of the bearing to the balancing chambers as i-n certain prior systems of the class to which the invention is directed.
  • the bearing recesses 21, 22, 23 are formed in the shaft and hence revolved bodily with the rotating assembly, accurate compensation is had continuously throughout every revolution.
  • auxiliary restricted orifices such as 30 shown in the connecting passages 25 may usually be omitted with good results when desired to obtain maximum response speed of the rebalancing system.
  • the insertion of the orifices 30 may be desirable in order to introduce some damping in the response characteristic. This may be especially useful in the case of a substantial gravity force component being present in the system, such as in the horizontal shaft system shown, since such a constant gravity component tends to induce cyclic pressure variations in the balancing chambers as the shaft rotates. Such cyclic pressure variations do not per se tend to produce relative shifting of the balancing rollers, since the mean values of the pressures remain constant.
  • the balancing section of the system including the continuous annular raceway or channel containing the plurality of, preferably three, balancing elements in the form of perforate rollers, in combination with the stop means 51, 52, 53 which positively limit the arcuate displacements of the rollers, as shown and described above, is highly advantageous for several reasons. While being simple and inexpensive to construct and assemble, the continuous annular channel ensures optimal transmission of pressure variations through the body of uid contained therein and hence optimal response to an unbalance; also the available length of displacement of the movable elements is increased for given over-all dimensions.
  • the stops positively prevent the straying of the balancing chambers all around the annular channel, which would otherwise result in incorrect operation since each balancing chamber 17, 18, 19 would then be liable to communicate with the wnong shaft recesses 21, 22, 23; said stops however do not substantially interfere with the continuous character of the annular raceway in regard to the transmission of pressure forces.
  • the cylindrical shape of the balancing elements 1l, 12, 13 makes them easy to machine to the requisite tolerances and the axial perforations through the elements ensure pressure balance between the opposite ends thereof as well as a self-lubricating effect conducive t-o smooth floating displacement of the rollers around the raceway to effect the desired compensating shifts.
  • a revolving assembly including a shaft, a bearing for supporting said shaft with a clearance space therebetween, said shaft having a bearing surface formed with a plurality of circumferentially spaced recesses, means defining in said assembly a continuous annular raceway coaxially surrounding the shaft; a plurality of balancing elements in the raceway displaceable along arcuate paths therein and defining a plurality of spaces between said.
  • said ducts include each an axially extending portion formed in said shaft, said portions opening into said raceway at angularly equispaced points substantially radially aligned with said stop means.
  • a revolving assembly including a shaft, a bearing for supporting said shaft with a clearance space therebetween, said shaft having a bearing surface formed with a plurality of circumferentially spaced recesses, means defining in said assembly a continuous annular raceway coaxially surrounding the shaft; a plurality of cylindrical elements in the raceway positioned with their axes parallel to the shaft axis and displaceable along arcuate paths in the raceway in substantially fluid-sealing freely-displaceable relationship with the walls thereof to define with said walls a plurality of arcuate spaces of variable volume; the number of said spaces being equal to the number of said recesses, angular- 1y equispaced stops in the raceway limiting the arcuate paths of travel of said elements and thereby preserving the relative disposition of the spaces defined between said elements Without substantially restricting the flow section of the raceway; and duct means connecting each of said spaces with one of said recesses, respectively, and

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Acoustics & Sound (AREA)
  • Aviation & Aerospace Engineering (AREA)
  • Magnetic Bearings And Hydrostatic Bearings (AREA)
US174160A 1961-02-28 1962-02-19 Dynamic balancing system for rotating structures Expired - Lifetime US3158039A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR854062A FR1290875A (fr) 1961-02-28 1961-02-28 Dispositif de compensation du balourd d'une pièce rotative

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US3158039A true US3158039A (en) 1964-11-24

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US174160A Expired - Lifetime US3158039A (en) 1961-02-28 1962-02-19 Dynamic balancing system for rotating structures

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US (1) US3158039A (enrdf_load_stackoverflow)
CH (1) CH377554A (enrdf_load_stackoverflow)
DE (1) DE1698523B1 (enrdf_load_stackoverflow)
FR (1) FR1290875A (enrdf_load_stackoverflow)
GB (1) GB951704A (enrdf_load_stackoverflow)
NL (1) NL275196A (enrdf_load_stackoverflow)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2428249A1 (fr) * 1978-06-08 1980-01-04 Clichy Const Sa Dispositif d'elimination du balourd residuel d'un organe rotatif
US8491265B2 (en) 2010-04-12 2013-07-23 Honeywell International Inc. Rotor imbalance load limiting system and method

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SE358939B (enrdf_load_stackoverflow) * 1972-06-06 1973-08-13 Reinhall Rolf
FR2422076A1 (fr) * 1978-04-06 1979-11-02 Hispano Suiza Sa Dispositif de reequilibrage automatique de systemes tournants
DE2905729A1 (de) * 1979-03-12 1980-10-02 Jurij Grigorievitsch Schivotov Einrichtung zum auswuchten von rotationskoerpern
SE506579C2 (sv) * 1995-08-18 1998-01-12 Skf Ab Metod och hopsättningsverktyg för tillverkning av en automatisk balanseringsenhet

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2659243A (en) * 1951-07-05 1953-11-17 Bbc Brown Boveri & Cie Apparatus for automatic balancing of rotating bodies
US2778243A (en) * 1952-06-26 1957-01-22 Bbc Brown Boveri & Cie Device for automatic balancing of rotating machine parts

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2659243A (en) * 1951-07-05 1953-11-17 Bbc Brown Boveri & Cie Apparatus for automatic balancing of rotating bodies
US2778243A (en) * 1952-06-26 1957-01-22 Bbc Brown Boveri & Cie Device for automatic balancing of rotating machine parts

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2428249A1 (fr) * 1978-06-08 1980-01-04 Clichy Const Sa Dispositif d'elimination du balourd residuel d'un organe rotatif
US4281563A (en) * 1978-06-08 1981-08-04 Constructions De Clichy Device for eliminating residual unbalance from a rotating element
US8491265B2 (en) 2010-04-12 2013-07-23 Honeywell International Inc. Rotor imbalance load limiting system and method

Also Published As

Publication number Publication date
NL275196A (enrdf_load_stackoverflow)
CH377554A (fr) 1964-05-15
GB951704A (en) 1964-03-11
DE1698523B1 (de) 1970-04-23
FR1290875A (fr) 1962-04-20

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