Abstract:
A rotating machine includes a stationary component, a rotating component that is moveable relative to the stationary component, and a balancing member detachably mounted to the rotating component. The balancing member includes a self-locking device that selectively engages the rotating component when in a locked position and disengages the rotating component, to permit removal of the balancing member, when in an unlocked position. In this manner, the self-locking device prevents the balancing component from becoming loose during operation of the rotating machine without requiring staking the balancing component to the rotating component.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The present invention pertains to the art of rotating machines and, more particularly, to a self-locking weight for balancing a rotating component of a rotating machine. 
         [0002]    In the manufacture of rotating machines, such as turbomachines, final balancing of rotating components is an essential and important step. In addition to final balancing after manufacture, periodic re-balancing of the rotating component is necessary in order to ensure proper operation and long operational life. Balancing is typically achieved by adding or removing weights to the rotating component, e.g., rotor, to compensate for deviations in rotor straightness and components mounted to the rotor, such as buckets and covers, or to lower vibration levels at which the turbomachine is operating. 
         [0003]    The weights are typically mounted in weight grooves or openings formed in the rotor. Weight grooves for turbomachines usually have a T-shaped or dovetail cross-section. The weight is positioned in the weight groove, moved to the proper angular position, and staked, peened or otherwise locked in place. Balance weight grooves that are intended for re-balancing during service are typically accessed through ports provided on a casing of the machine. Rebalance weights are fit into a balance groove and typically require a special installation tool or are of a screw plug type. In either case, the weights must be staked or peened in place to prevent loosening during operation of the turbomachine. 
         [0004]    When the rotor is serviced, e.g., provided with new field windings, the weights are removed so that the rotor can be rebalanced. Removal of the weights requires grinding off the stake or peen. The stake cannot be ground off when the rotor is in place. Grinding the stake in place would introduce debris into the turbomachine which, if not completely removed, could cause damage. Thus, the rotor must be removed, transported to a balance facility, balanced, and returned to service. This process can take as long as 2-3 weeks and can add considerably to machine down time. A power plant, for example, can loose significant in revenue each day the turbomachine is out of service. In addition, there is a limited number of times that a stake can be removed and reformed. Each removal and reforming, i.e., unlock/lock cycle, results in material loss to the rotor. After several such cycles, the rotor requires removal so the weight groove can be enlarged allowing additional lock/unlock cycles. 
       BRIEF DESCRIPTION OF THE INVENTION 
       [0005]    In accordance with one aspect of the present invention, a rotating machine is provided. The rotating machine includes a stationary component and a rotating component that is moveable relative to the stationary component. The rotating component includes a balancing member receiving opening. The rotating machine also includes a balancing member that is detachably mounted to the rotating component at the balancing member receiving opening. The balancing member includes a self-locking device that selectively engages the rotating component when in a locked position and disengages the rotating component, to permit removal of the balancing member, when in an unlocked position. In this manner, the self-locking device prevents the balancing component from becoming loose during operation of the rotating machine without requiring slaking the balancing component to the rotating component. 
         [0006]    In accordance with another aspect of the present invention, a method of balancing a rotating member of a rotating machine is provided. The method includes exposing a balancing member receiving portion of the rotating member, partially inserting a balancing member having a self-locking device into the balancing member receiving portion, and operating a lock member actuator of the self-locking device. Once the lock member actuator is operated, a locking member of the self-locking device is retracted into the balancing member. At this point, the balancing member is scaled in the balancing member receiving portion, the lock member actuator is disengaged and the lock member is extended into engagement with the rotating member to prevent the balancing member from becoming loose during operation of the rotating machine. 
         [0007]    Based on the above, it should be appreciated that exemplary embodiments of the present invention provide a balancing member that can be installed on a rotating component of a rotating machine without requiring staking or peening. In addition, the exemplary embodiments illustrate a balancing member that can be easily removed without requiring disassembly of the rotating machine and removal of the rotary component. In this manner, the present invention shortens rotating machine down time thereby increasing operating efficiency and reducing operational and maintenance costs. In any event, additional objects, features and advantages of various aspects of exemplary embodiments of the present invention will become more readily apparent from the following detailed description when taken in conjunction with the drawings wherein like reference numerals refer to corresponding parts in the several views. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]      FIG. 1  is a partial cross-sectional view of a rotating machine having a rotary component including a self-locking balancing member constructed in accordance with an exemplary embodiment of the present invention; 
           [0009]      FIG. 2  is a partial perspective view of the rotary component and self-locking balancing member of  FIG. 1 ; 
           [0010]      FIG. 3  is a cross-sectional side view of a self-locking balancing member of constructed in accordance with a first exemplary embodiment of the present invention shown in a locked configuration; 
           [0011]      FIG. 4  is a cross-sectional side view of the self-locking balancing member of  FIG. 4  shown in an unlocked configuration; 
           [0012]      FIG. 5  is a lower perspective view of the self-locking balancing member of  FIG. 3 ; 
           [0013]      FIG. 6  is a cross-sectional side view of a self-locking balancing member constructed in accordance with a second exemplary embodiment of the present invention shown in a locked configuration; 
           [0014]      FIG. 7  is a cross-sectional side view of a self-locking balancing member constructed in accordance with a third exemplary embodiment of the present invention shown in a locked configuration; 
           [0015]      FIG. 8  is a cross-sectional side view of the self-locking balancing member of  FIG. 7  shown in an unlocked configuration; 
           [0016]      FIG. 9  is a partial cross-sectional view of a fan support in accordance with an exemplary embodiment of the present invention; and 
           [0017]      FIG. 10  is a perspective view of a self-locking balancing member constructed in accordance with a fourth exemplary embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0018]    With Initial Reference to  FIGS. 1-2 , a rotary or rotating machine constructed in accordance with an exemplary embodiment of the present invention is illustrated as a turbomachine indicated generally at  2 . Turbomachine  2  includes a stationary member or stator  4  having a plurality of slacked laminations indicated generally at  6  that are held in place by a flange  8 . Turbomachine  2  further includes a rotating member or rotor  10 . Rotor  10  includes a main body  11  having an outer surface  13 . Rotor  10  is also shown to include a fan support  14  that provides mounting structure for a fan assembly (not shown) that generates cooling air flow. As shown, rotor  10  is spaced from stator  4  by an air gap  15 . Access to air gap  15  is obtained through an entrance gap  17  located adjacent flange  8 . Rotor  10  includes a plurality of balancing member receiving openings  20 - 23 , each of which includes a plurality of internal threads  24  and lock member receivers  25  and  26 , such as shown in connection with balancing member receiving opening  20 . Of course, the number, location and shape of lock member receivers  25  and  26  can vary. As will be discussed more fully below, a weight balancing member  40  is mounted in one or more of the plurality of balancing member receiving openings  20 - 23  to provide a dynamic balance for rotor  10 . 
         [0019]    Reference will now be made to  FIG. 3-5  in describing balancing member  40  constructed in accordance with a first exemplary embodiment of the present invention. Balancing member  40  includes a main body portion  42  having a first surface  43  provided with a recessed portion  44  shown in the form of a hexagon. First surface  43  extends to a second surface  45  through an outer wall  46 . Outer wall  46  is provided with a plurality of threads  47  configured to engage with threads  24  provided in, for example, balancing member receiving opening  20 . Main body portion  42  includes a locking device housing  49  having a lock member actuator portion  52  and a lock member portion  55  that are accessed by opening a removable cap member  57 . As shown in  FIG. 3 , cap member  57  is detachably mounted to second surface  45  of main body portion  42 . 
         [0020]    Lock member actuator portion  52  includes a first end portion  65  that extends to a second end portion  66  through an intermediate portion  67 . Intermediate portion  67  includes a tapered or angled wall segment  69  that establishes a narrow region  70  at first end portion  65 . In a similar manner, lock member portion  55  includes a first end portion  72  that extends to a second end portion  73  through an intermediate portion  74 . Lock member portion  55  actually bisects, lock member actuator portion  52 . As will become more evident below, lock member portion  55  includes first and second opposing lock member sections  58  and  59  that extend from lock member actuator portion  52 . In any event, first and second end portions  72  and  73  are peened, staked, or otherwise retained, e.g. by a c-clip, bolt, etc., to create a narrow diameter region (not separately labeled). 
         [0021]    Balancing member  40  also includes a self-locking device  76  including a lock member actuator  84  and, in the exemplary embodiment shown, a pair of lock members  85  and  86 . Lock member actuator  84  is positioned within lock member actuator portion  52  and includes a first end section  87  that extends to a second end section  88  through an intermediate section  89 . Intermediate section  89  includes a tapered section  91  that corresponds to tapered wall segment  69  of lock member actuator portion  52 . First end section  88  extends through narrow region  70  and projects into receded portion  44 . In accordance with the exemplary embodiment shown, lock member actuator  84  is selectively shiftable between a first or locked position, such as illustrated in  FIG. 3 , and a second or unlocked position, such as shown in  FIG. 4  as will be discussed more fully below. In any event, a spring  93  biases lock member actuator  84  in the first or locked position. Spring  93  is held in place by a locking clip  94  accessed through cap member  57  as shown in  FIG. 5 . Locking clip  94  enables spring  93  to be conical in shape to reduce an overall height of balancing member  40 . In addition, to spring  93  biasing lock member actuator in the locked position, centrifugal force generated by rotor  10  further acts to lock balancing member  40  in place. 
         [0022]    When in the locked position lock member actuator  84  urges lock members  85  and  86  shown, in the form of first and second pairs of locking spheres or ball bearings  96 ,  97  and  98 ,  99 , out from main body portion  42 . When installed in one of the plurality of balancing member receiving openings  20 - 23 , into lock member receiver  25 . That is, lock member  85  extends beyond outer wall  46  and into lock member receiver  25  to prevent balancing member  40  from becoming loose during operation of a turbomachine  2 . In order to insert balancing member  40  into balancing member receiving opening  20 , a tool (not shown) is inserted into recessed portion  44  to depress first end section  87  of lock member actuator  84 . As first end a section  88  is depressed into recessed portion  44 , lock member actuator  84  shifts within lock member actuator portion  52  against the force provided by spring  93 . As lock member actuator  84  travels within lock member actuator housing  49 , ball bearings  96  and  98  move along tapered section  91 . As tapered section  91  is shifted into position, lock members  85  and  86  retract into to main body portion  42 . At this point, balancing member  40  is threaded into balancing member receiving opening  20 . Once in position, lock member portion  55  is aligned with lock member receiver  25  and  26 , the tool is removed, and lust end portion  88  is released. Once released, spring  93  urges lock member actuator  84  to the locked position causing tapered section  91  to urge lock members  85  and  86  into lock member receiver  25  and  26 . In this manner, locking device  76  is selectively resiliently biased to engage rotor  10  when in a locked position and disengage from rotor  10  to permit removal and or installation of balancing member  40  when in an unlocked position Removal of balancing member  40  is achieved by reversing the above described operation. 
         [0023]    Reference will now be made to  FIG. 6  in describing a balancing member  140  constructed in accordance with a second exemplary embodiment of the present invention. Balancing member  140  includes a main body portion  142  having a first surface  143  provided with a recessed portion  144 . First surface  143  extends to a second surface  145  through an outer wall  146 . As shown, outer wall  146  includes a plurality of threads, indicated generally at  147 , that correspond to threads  24  in each of the plurality of balancing member receiving openings  20 - 23 . In a manner similar to that described above, balancing member  140  includes a locking device housing  149  that includes a lock member actuator portion  152  and a lock member portion  155  that are accessed via a detachably mounted cap member  157 . As will become more evident below, lock member portion  155  includes first and second opposing lock member sections  158  and  159  that extend at an angle from lock member actuator portion  152  towards first surface  143 . 
         [0024]    In a manner also similar to that described above, lock member actuator portion  152  includes a first end portion  165  that extends to a second end portion  166  through an intermediate portion  167 . In manner similar to that described above, intermediate portion  167  includes a tapered or angled wall segment  169  that provides a transition to a narrow region  170  at first end portion  165 . Lock member sections  158  and  159  are identical such that a description will follow with respect to lock member section  158  with an understanding that lock member section  159  is similarly formed. As shown, lock member section  158  includes a first end portion  172  that extends to a second end portion  173  through an intermediate portion  174 . First end portion  172  is staked, peened or otherwise locked to establish a narrow diameter portion at outer wall  146 . As noted above, lock member section  158  extends at an angle from lock member actuator portion  152  towards first surface  143 . 
         [0025]    Balancing member  140  is also shown to include self-locking device  176  including a lock member actuator  184  and first and second lock members  185  and  186 . Lock member actuator  184  is positioned within lock member actuator portion  152  and includes a first end section  187  that extends to a second end section  188  through an intermediate section  189 . Intermediate section  189  includes a tapered section  191  that corresponds to tapered wall segment  169  of lock member actuator portion  152 . First end section  188  extends through narrow region  170  and projects into receded portion  144 . A spring  193  biases lock member actuator  84  in the first or locked position. Spring  193  is held in place by a locking clip (not shown). 
         [0026]    As shown, lock members  185  and  186  include first and second pairs of locking spheres or ball bearings  196 ,  197  and  198 ,  199 . Lock member actuator  184  is positioned within lock member actuator portion  152  and is selectively shiftable between a first or locked position and a second or unlocked position. When in the unlocked position, the angle of lock member sections  158  and  159  facilitates the transition of ball bearings  196 - 199  between corresponding locked and unlocked configurations. That is, when lock member actuator  184  is in the unlocked position, ball bearings  196 - 199  roll along respective lock member sections  158  and  159  and retract into main body portion  142 . To facilitate insertion and removal from rotor  10  in a manner similar to that described above. 
         [0027]    Reference will now be made into  FIGS. 7-8  in describing a balancing member  240  constructed in accordance with a third exemplary embodiment of the present invention. Balancing member  240  includes a main body portion and  242  having a first surface  243  provided with a recessed portion  244 . First surface  243  extends to a second surface  245  through an outer wall  246 . Outer wall  246  includes a plurality of threads, indicated generally at  247 , that are configured to engage with threads  24  provided in each the plurality of balancing member receiving openings  20 - 23 . In a manner similar to that described above, balancing member  240  includes a locking device housing  249  including a lock member actuator portion  252  and a lock member portion  255  that are accessed via a detachably mounted cap member  257 . 
         [0028]    Lock member actuator portion  252  includes a first end portion  265  that extends to a second end portion  266  through an intermediate portion  267 . First end portion  265  transitions to a narrow region  270  that leads into recessed portion  244 . Lock member portion  255  includes a first end portion  272  that extends to a second end portion  273  through an intermediate portion  274 . Lock member portion  255  actually bisects, at an angle, lock member actuator portion  252 . In any event, balancing member  240  also includes a self-locking device  276  having a lock member actuator  284  and a lock member  285 . Lock member actuator  284  is shiftably mounted within lock member actuator portion  252 . As shown, lock member actuator  284  includes a first end portion  287  that extends to a second end portion  288 . First end portion  287  includes a rounded member  291  that is designed to engage with lock member  285  as will be detailed below. 
         [0029]    In accordance with the embodiment shown, lock member  285  includes a first end  300  that extends to a second end  301  through an intermediate portion  302  including first and second opposing surfaces  304  and  305 . First surface  304  is provided with a lock member actuator receiver  310  having an angled surface  312  configured to inter-engage with rounded member  291  when lock member actuator  284  is shifted to the unlocked position such as shown in  FIG. 8 . More specifically, in the locked position, such as illustrated in  FIG. 7 , a spring  314  biases lock member  298  outward so as to extend through outer wall  246 . In addition, centrifugal force generated by rotor  10  further locks lock member  285  in place. When lock member actuator  285  is shifted to the unlocked position (see  FIG. 8 ) such as by inserting a tool (not shown) into recessed portion  244 , rounded member  291  moves into contact with angled surface  312  of lock member actuator receiver  310 . Further shifting of lock member actuator  284  moves lock member  285  into main body portion  242 . At this point, balancing member  242  can be inserted into or removed from for example, rotor  10 . 
         [0030]    Reference will now be made to  FIGS. 9 and 10  in describing another exemplary embodiment of the present invention. In addition to providing balancing member assembly receiving opening  20 - 23  on rotor  10 , rotating machine  2  also includes a balancing member receiving section  350  provided on fan support  14 . Balancing member receiving section  350  is defined by a slot  355  that extends about an inner circumference of fan support  14 . Slot  355  includes a plurality of notches, one of which is indicated at  365 . Notches  365  define discrete balancing positions fan support  14 . 
         [0031]    As shown in  FIG. 10 , a self-locking balancing member  370  having a generally T-shaped configuration includes a self-locking device  373  having a lock member actuator  380  that is selectively depressed to release a pair of opposing locking members  385  and  386 . With this arrangement, lock member actuator  380  is depressed and self-locking balancing member  370  is inserted into slot  355  and moved to a desired balancing position. Once in the desired balancing position, lock member actuator  380  is released allowing locking members  385  and  386  to engage corresponding notches  365  to lock balancing member  370  to support  14 . Of course, it should be understood that the slot  355  could includes a dove tail configuration, such as shown in  FIG. 1 , with balancing member  370  including complimentary structure. 
         [0032]    At this point, it should be appreciated that the present invention provides a balancing member that can be installed on a rotating member of a turbomachine without requiring slaking or peening. In addition, the exemplary embodiments illustrate a balancing member that can be easily removed without requiring disassembly of the turbomachine and removal of the rotor. In this manner, the present invention shortens turbomachine down time thereby increasing operating efficiency and reducing operational and maintenance costs. Furthermore, it should be understood that while shown in pairs, single lock members could also be employed. Also the cap member can be made integral with the main body while still providing access to the clip to allow removal and installation of the spring. 
         [0033]    In general, this written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may be includes other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the present invention if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims.