Abstract:
An elevator system includes a hoistway; an elevator car to travel in the hoistway, the elevator car having permanent magnets mounted thereto; a stator mounted in the hoistway, the stator coacting with the permanent magnets to control motion of the elevator car in the hoistway, the stator including: a plurality of modular coil modules, each coil module including stacked coil assemblies, each coil assembly including stacked coil units, each coil unit corresponding to one phase of the stator.

Description:
FIELD OF INVENTION 
       [0001]    The subject matter disclosed herein relates generally to the field of elevators, and more particularly, to a stator structure for a self-propelled elevator. 
       BACKGROUND 
       [0002]    Self-propelled elevator systems, also referred to as ropeless elevator systems, are useful in certain applications (e.g., high rise buildings) where the mass of the ropes for a roped system is prohibitive and/or there is a need for multiple elevator cars in a single hoistway. 
       SUMMARY 
       [0003]    According to an exemplary embodiment of the invention, an elevator system includes a hoistway; an elevator car to travel in the hoistway, the elevator car having permanent magnets mounted thereto; a stator mounted in the hoistway, the stator coacting with the permanent magnets to control motion of the elevator car in the hoistway, the stator including: a plurality of modular coil modules, each coil module including stacked coil assemblies, each coil assembly including stacked coil units, each coil unit corresponding to one phase of the stator. 
         [0004]    According to another exemplary embodiment of the invention, a propulsion system includes a movable portion comprising a plurality of permanent magnets; and a stationary portion comprising a plurality of phase coil units configured to be stacked along a movement direction, adjoining ones of the phase coil units configured to be connected to power inputs having different phases to provide a motive force to the movable portion. 
         [0005]    Other aspects, features, and techniques of embodiments of the invention will become more apparent from the following description taken in conjunction with the drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]    Referring now to the drawings wherein like elements are numbered alike in the FIGURES: 
           [0007]      FIG. 1  depicts a self-propelled elevator system in an exemplary embodiment; 
           [0008]      FIGS. 2-4  depict coil units in an exemplary embodiment; 
           [0009]      FIGS. 5-6  depict coil assemblies in an exemplary embodiment; 
           [0010]      FIG. 7  depicts a coil module in an exemplary embodiment; 
           [0011]      FIG. 8  depicts a coil module and housing in an exemplary embodiment; 
           [0012]      FIG. 9  depicts a junction of two coil modules in an exemplary embodiment; 
           [0013]      FIG. 10  depicts attachment of a coil module to a support structure in an exemplary embodiment; and 
           [0014]      FIG. 11  depicts attachment of a coil module to a support structure in an exemplary embodiment. 
       
    
    
     DETAILED DESCRIPTION 
       [0015]      FIG. 1  depicts an elevator system  10  having a self-propelled elevator car  12  in an exemplary embodiment. Elevator system  10  includes an elevator car  12  that travels in a hoistway  14 . Elevator car  12  is guided by one or more guide rails  16  extending along the length of hoistway  14 . Elevator system  10  employs a linear motor having a stator  18  including a plurality of stacked, modular coil modules as described in further detail herein. Stator  18  may be mounted to guide rail  16 , incorporated into the guide rail  16 , act as the guide rail  16 , or located apart from guide rail  16 . Stator  18  serves as one portion of a permanent magnet linear motor to impart motion to elevator car  12 . Permanent magnets  19  are mounted to car  12  to provide a second portion of the permanent magnet linear motor. Coil units of stator  18  may be arranged in three phases, as is known in the linear motor art. Two or more stators  18  may be positioned in the hoistway  14 , to coact with permanent magnets  19  mounted on two sides of elevator car  12 . 
         [0016]    A controller  20  provides drive signals to the stator(s)  18  to control motion of the elevator car  12 . Controller  20  may be implemented using a general-purpose microprocessor executing a computer program stored on a storage medium to perform the operations described herein. Alternatively, controller  20  may be implemented in hardware (e.g., ASIC, FPGA) or in a combination of hardware/software. Controller  20  may also be part of an elevator control system. Controller  20  may include power circuitry (e.g., an inverter or drive) to power the stator(s)  18 . 
         [0017]      FIGS. 2-4  depict coil units in exemplary embodiments.  FIG. 2  depicts a coil unit  30  for a first phase of stator  18 . First phase coil unit  30  includes a generally rectangular coil  32  having a central air core. Coil  32  may be formed using wire (e.g., aluminium), conductive tape, etc. First phase coil unit  30  includes a first connector  34  and a second connector  36 . First connector  34  is a generally tab shaped element, and extends from coil  32  along a direction of hoistway  14 . First connector  34  has a height greater than the height of three coil units. As described herein, first connector  34  electrically connects with a second connector  36  of an upper first phase coil unit positioned above first phase coil unit  30  in a coil module. 
         [0018]    Second connector  36  is located where first connector  34  joins coil  32 . Second connector  36  may be a u-shaped connector that makes electrical connection with a first connector of a lower first phase coil unit positioned below first phase coil unit  30  in a coil module. First connector  34  and second connector  36  are located adjacent a first edge  38  of coil unit  30 . 
         [0019]      FIG. 3  depicts a coil unit  40  for a second phase of stator  18 . Second phase coil unit  40  is similar to first phase coil unit  30 , and includes a coil  42 , a first connector  44  and second connector  46 . Coil  42 , first connector  44  and second connector  46  are similar in construction to a coil  32 , first connector  34  and second connector  36 . First connector  44  has a height greater than the height of three coil units. First connector  44  and second connector  46  are centrally located on coil  42 , between first edge  48  and second edge  49  of coil  42 . 
         [0020]      FIG. 4  depicts a coil unit  50  for a third phase of stator  18 . Third phase coil unit  50  is similar to first phase coil unit  30 , and includes a coil  52 , a first connector  54  and second connector  56 . Coil  52 , first connector  54  and second connector  56  are similar in construction to coil  32 , first connector  34  and second connector  36 . First connector  54  has a height greater than the height of three coil units. First connector  54  and second connector  56  are located adjacent a second edge  59  of coil unit  50 . When stacked, second edge  59  of third phase coil unit  50  is opposite first edge  38  of first phase coil unit  30 . 
         [0021]      FIG. 5  depicts coil units  30 ,  40  and  50  stacked into a coil assembly  60 . Additional coil units may be stacked to form a coil module, as shown in  FIG. 7 . If the coil assembly  60  is located at the bottom of a coil module, terminals  62 ,  64  and  66  extend from first phase second connector  36 , second phase second connector  46 , and third phase second connector  56 , respectively. Terminals  62 ,  64  and  66  are arranged along a single axis and provide a location to electrically connect the phases of a first coil module to a second coil module, or a location to apply drive signals. 
         [0022]      FIG. 6  depicts a coil assembly  70  made up of stacked coil units  30 ,  40  and  50 . Coil assembly  70  is configured for placement at the top of a coil module. As such, terminals  72 ,  74  and  76  extend from first phase first connector  34 , second phase first connector  44 , and third phase first connector  54 , respectively. Terminals  72 ,  74  and  76  are arranged along a single axis and provide a location to electrically connect the phases of a first coil module to a second coil module, or a location to apply drive signals. 
         [0023]      FIG. 7  depicts a coil module  80  formed from a stack of coil units  30 ,  40  and  50 . Coils units in coil module  80  follow a pattern of first phase coil unit  30 , second phase coil unit  40 , third phase coil unit  50 , first phase coil unit  30 , etc. The respective phases (e.g., first, second and third) are electrically connected by the first phase first connector  34 , second phase first connector  44 , and third phase first connector  54 . The bottom coil assembly may be formed as shown in  FIG. 5 , with terminal  62 ,  64  and  66  arranged on a single axis. The top coil assembly may be formed as shown in  FIG. 6 , with terminal  72 ,  74  and  76  arranged on a single axis. 
         [0024]      FIG. 8  depicts coil module  80  mounted to a housing  90 . Housing  90  may be formed from a non-conductive material (e.g., plastic). Housing  90  forms at least one wall of the coil module  80 . Coil module  80  may be positioned in housing  90  and the entire assembly impregnated with a curing material, such as concrete with a filler, such as plastic filler, fiber glass or carbon fiber. Once the curing material cures, the coil module  80  and housing  90  are fused and formed a structurally rigid coil module  80 . Housing  90  may include one or more openings to provide access to the coil units. Each end of housing  90  may include a recess  92  that provides access to terminals  62 ,  64  and  66  at one end and terminals  72 ,  74  and  76  at another end. Openings  94  may be formed in housing  90  at multiple locations to provide access to coil units in the coil module. The interior of the coil module  80  may be left open or hollow. This provides for enhanced dissipation and transfer of heat generated in the coil module  80 . The channel defined by the interior of the coil module  80  may also serve also as a conduit for cables, pipes, etc., distributed along the hoistway  14 . 
         [0025]    Coil module  80  may be about 3 m in height, A plurality of coil modules  80  are stacked vertically in hoistway  14  to provide stator  18 .  FIG. 9  illustrates a junction between two coil modules  80  and  80 ′. Recesses  92  and  92 ′ in housings  90  and  90 ′ provide an area to access upper terminals  62 ,  64  and  66  of coil module  80  and lower terminals  72 ,  74  and  76  of coil module  80 ′. This allows the coil modules to be electrical connected. A gap  94  may be provided between coil module  80  and coil module  80 ′. Gap  94  allows the coil modules  80  and  80 ′ to move relative to each other to accommodate building sway, forces on the coil modules, etc. A flexible material (e.g., an elastic member) may be placed in gap  94  between coil module  80  and coil module  80 ′. 
         [0026]      FIG. 10  depicts mounting of coil module  80  to a support structure  100 . Support structure  100  may be made from metal and c-shaped or L-shaped, for example, to increase rigidity. Support structure  100  may form a portion of guide rail  16  or may be separate from guide rail  16 . Support structure  100  may run the entire length of hoistway  14 , or may include a plurality of support structures  100 , each supporting one or more coil modules  80 . A u-shaped bracket  102  extends over coil module  80  and is secured to support structure  100  by fasteners  104  to secure coil module  80  to support structure  100 . A plurality of brackets  102  may be used to secure coil module  80  to support structure  100 . Loads acting on the coil module  80  are transferred to the support structure  100 , which may be mounted to the wall of hoistway  14 . 
         [0027]      FIG. 11  depicts mounting of coil module  80  to support structure  100  in an exemplary embodiment. Housing  90  of coil module  80  includes a protrusion  110 . Support structure  100  includes an opening  112  for receiving protrusion  110  to fasten coil module  80  to support structure  100 . Protrusion  110  may be press fit into opening  112 . Alternatively, an adhesive or fastener may be used to secure the connection between protrusion  110  and opening  112 . It is understood that multiple protrusions  110  and openings  112  may be formed on the coil module  80  and support structure  100 , respectively. Loads acting on the coil module  80  are transferred to the support structure  100 , which may be mounted to the wall of hoistway  14 . 
         [0028]    Embodiments provide numerous benefits. The coil modules have a simple mechanical structure and a toothless electromagnetic configuration, constructed from inexpensive materials. The coil modules provide for modular fabrication allowing prefabrication and a repeatable process allowing for automation of production. The flexible connection between coil modules enables handling building sways without structural damage. The coil modules also provide enhanced thermal performance, by using materials with low thermal expansion and large surface areas for heat removal, warranting thermal stability. 
         [0029]    Embodiments provide a robust design, with rigid mechanical structures and simple mounting methods. Electrical separation between phase coils provides low insulation voltage stress and provides a durable stator system. Modular coil modules result in simple, quick installation. The prefabricated coil modules may be installed in the hoistway on the job site and then electrically connected one to each other. Replacement of a malfunctioning coil module is routine, as each coil module can be disconnected electrically and detached mechanically and replaced with new one. 
         [0030]    The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. While the description of the present invention has been presented for purposes of illustration and description, it is not intended to be exhaustive or limited to the invention in the form disclosed. Many modifications, variations, alterations, substitutions, or equivalent arrangement not hereto described will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the invention. Additionally, while the various embodiments of the invention have been described, it is to be understood that aspects of the invention may include only some of the described embodiments. Accordingly, the invention is not to be seen as being limited by the foregoing description, but is only limited by the scope of the appended claims.