Patent Publication Number: US-2023155442-A1

Title: Stator, motor, and compressor

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This is a continuation of International Application No. PCT/JP2021/018660 filed on May 17, 2021, which claims priority to Japanese Patent Application No. 2020- 127325, filed on Jul. 28, 2020. The entire disclosures of these applications are incorporated by reference herein. 
    
    
     BACKGROUND 
     Technical Field 
     The present disclosure relates to a stator, a motor, and a compressor. 
     Background Art 
     A known stator has neutral lines and lead wires fixed to an upper insulator, with the neutral lines and the lead wires not orderly separated from each other and from coils (see, for example, JP 3824001 B2). 
     When the stator described above is used in a motor disposed in a hermetic container of a compressor, the neutral lines and the lead wires prevent an enough gap from being provided between the coils, so that a cross-sectional area of a passage between the coils through which a refrigerant flows becomes insufficient, causing oil to be discharged along with the refrigerant due to an increase in flow velocity of the refrigerant flowing between the coils, thus escape of oil from the compressor cannot be prevented accordingly. 
     SUMMARY 
     The present disclosure proposes a stator capable of preventing oil from escaping, or leaking, through a gap between coils when used in a motor of a compressor. 
     The present disclosure further provides a motor including the stator. 
     The present disclosure further provides a compressor including the motor. 
     A stator of the present disclosure includes a stator core having a plurality of teeth, an insulator mounted to an axial end surface of the stator core, a plurality of coils with each coil wound around a corresponding one of the plurality of teeth of the stator core, a first region in which a distal end of a feeder line extending from a first end of one of the coils is connected to a distal end of a feeder line extending from a first end of an other one of the coils, and a second region in which distal ends of neutral lines extending from second ends of the coils are connected to each other. The insulator has an inner wall and an outer wall spaced from each other in a radial direction of the stator core. Both the first region and the second region are partially disposed axially above the stator core between the inner wall and the outer wall of the insulator. In a cross section at a gap between at least two adjacent coils of the plurality of coils, taken along a plane including an axis of the stator core, a center of gravity of the first region is positioned above a center of gravity of the second region in an axial direction of the stator core. B &lt; A and C &lt; A, where a radial length of the first region is B, a radial length of the second region is C, and a radial length between the inner wall and the outer wall of the insulator is A. 
     A motor of the present disclosure includes the stator, and a rotor disposed radially inside of the stator. 
     A compressor of the present disclosure includes a hermetic container, a compression mechanism part disposed in the hermetic container, and the motor disposed in the hermetic container and configured to drive the compression mechanism part. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a perspective view of a stator of a first embodiment of the present disclosure. 
         FIG.  2    is a longitudinal cross-sectional view of the stator. 
         FIG.  3    is a diagram illustrating how coils of the stator are connected. 
         FIG.  4    is a schematic diagram illustrating how the coils illustrated in  FIG.  3    are connected. 
         FIG.  5    is a top view of the stator. 
         FIG.  6    is a schematic cross-sectional view of an important part of the stator. 
         FIG.  7    is a schematic cross-sectional view of the part of the stator. 
         FIG.  8    is a schematic cross-sectional view of an important part of a stator of a second embodiment of the present disclosure. 
         FIG.  9    is a cross-sectional view of a compressor including a motor of a third embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENT(S) 
     Embodiments will be described below. It should be noted that in the drawings, the same reference numerals represent the same or corresponding parts. In addition, the dimensions on the drawings, such as lengths, widths, thicknesses, and depths, are appropriately changed from actual scales for clarity and simplification of the drawings, and do not represent actual relative dimensions. 
     First Embodiment 
       FIG.  1    is a perspective view of a stator  1  of a first embodiment of the present disclosure, and  FIG.  2    is a longitudinal cross-sectional view of the stator. 
     As illustrated in  FIGS.  1  and  2   , the stator  1  has a stator core  10 , an upper insulator  20  mounted to an axially upper end surface of the stator core  10 , a lower insulator  30  mounted to an axially lower end surface of the stator core  10 , and coils U 1  to U 4 , V 1  to V 4 , W 1  to W 4  wound around the stator core  10 , the upper insulator  20 , and the lower insulator  30  as assembled together. 
     The upper insulator  20  and the lower insulator  30  are made of an insulating resin. 
     The stator core  10  has a back yoke  11  having an annular shape, and a plurality of teeth  12  protruding radially inward from an inner peripheral surface of the back yoke  11 . 
     The coils U 1  to U 4 , V 1  to V 4 , W 1  to W 4  are each wound around a corresponding one of the teeth  12  rather than being distributedly wound around the teeth  12 , which is a so-called concentrated winding. 
       FIG.  3    is a diagram illustrating how the coils U 1  to U 4 , V 1  to V 4 , W 1  to W 4  of the stator  1  are connected, and  FIG.  4    is a schematic diagram illustrating how the coils U 1  to U 4 , V 1  to V 4 , W 1  to W 4  illustrated in  FIG.  3    are connected.  FIG.  3    is a top view of the stator core  10  with the upper insulator  20  removed. 
     Twelve feeder lines  e U 1  to  e U 4 ,  e V 1  to  e V 4 ,  e W 1  to  e W 4  corresponding to winding start portions of windings of the coils U 1  to U 4 , V 1  to V 4 , W 1  to W 4 , respectively, emerge from the upper end surface of the stator core  10 . Twelve neutral lines  c U 1  to  c U 4 ,  c V 1  to  c V 4 ,  c W 1  to  c W 4  corresponding to winding end portions of the windings of the coils U 1  to U 4 , V 1  to V 4 , W 1  to W 4 , respectively, also emerge from the upper end surface of the stator core  10 . 
     The feeder lines  e U 1 ,  e U 2  extend from first ends of the windings of the coils U 1 , U 2 , respectively, to connect to a U-phase connection part X Ua . The feeder lines  e U 3 ,  e U 4  extend from first ends of the windings of the coils U 3 , U 4 , respectively, to connect to a U-phase connection part X Ub . 
     The feeder lines  e V 1 ,  e V 2  extend from first ends of the windings of the coils V 1 , V 2 , respectively, to connect to a V-phase connection part X Va . The feeder lines  e V 3 ,  e V 4  extend from first ends of the windings of the coils V 3 , V 4 , respectively, to connect to a V-phase connection part X Vb . 
     The feeder lines  e W 1 ,  e W 2  extend from first ends of the windings of the coils W 1 , W 2 , respectively, to connect to a W-phase connection part Xw a . The feeder lines  e W 3 ,  e W 4  extend from first ends of the windings of the coils W 3 , W 4 , respectively, to connect to a W-phase connection part X Wb . 
     The coils U 1  to U 4 , V 1  to V 4 , W 1  to W 4  are fixed by winding, so that the feeder lines  e U 1  to  e U 4 ,  e V 1  to  e V 4 ,  e W 1  to  e W 4  corresponding to the winding start portions do not loosen even without being fixed to the stator core  10 . 
     The neutral lines  c U 1  to  c U 4  extend from second ends of the windings of the coils U 1  to U 4 , respectively, to connect to a neutral point N. The neutral lines  c V 1  to  c V 4  extend from second ends of the windings of the coils V 1  to V 4 , respectively, to connect to the neutral point N. The neutral lines  c W 1  to  c W 4  extend from second ends of the windings of the coils W 1  to W 4 , respectively, to connect to the neutral point N. At the neutral point N, all the neutral lines  c U 1  to  c U 4 ,  c V 1  to  c V 4 ,  c W 1  to  c W 4  are electrically connected. 
     The feeder lines  e U 1  to  e U 4 ,  e V 1  to  e V 4 ,  e W 1  to  e W 4  and the neutral lines  c U 1  to  c U 4 ,  c V 1  to  c V 4 ,  c W 1  to  c W 4  are latched, or secured, to the upper insulator  20  mounted to the upper end surface of the stator core  10  so as not to be electrically connected to each other. 
       FIG.  5    is a top view of the stator  1 . As illustrated in  FIG.  5   , an insulating cap  110  covering one U-phase connection part X Ua  (illustrated in  FIGS.  3  and  4   ) and an insulating cap  120  covering the other U-phase connection part X Ub  (illustrated in  FIGS.  3  and  4   ) are placed on their respective coil ends with the insulating cap  110  and the insulating cap  120  shifted from each other in a circumferential direction. 
     Likewise, an insulating cap  110  covering one V-phase connection part and an insulating cap  120  covering the other V-phase connection part are placed on their respective coil ends with the insulating cap  110  and the insulating cap  120  shifted from each other in the circumferential direction. 
     Likewise, an insulating cap  110  covering one W-phase connection part and an insulating cap  120  covering the W-phase connection part are placed on their respective coil ends with the insulating cap  110  and the insulating cap  120  shifted from each other in the circumferential direction. 
     A lead wire  111 , a lead wire  121 , the insulating caps  110 , the insulating caps  120 , and other lead wires are fixed to the upper insulator  20  by a plurality of binding threads (not illustrated). 
     In  FIG.  5   , Y denotes a gap between adjacent ones of the coils U 1  to U 4 , V 1  to V 4 , W 1  to W 4 , and Z denotes a radial length of an opening of an upward passage in the gap Y. A cross-sectional area of the passage (passage cross-sectional area) in which a flow path is formed is approximately Y * Z. 
       FIGS.  6  and  7    are schematic cross-sectional views of an important part of the stator  1 . In  FIGS.  6  and  7   , the same components as those illustrated in  FIGS.  1  and  2    are denoted by the same reference signs.  FIGS.  6  and  7    are cross-sectional views of the coil U 1  among the plurality of coils U 1  to U 4 , V 1  to V 4 , W 1  to W 4 , taken along a plane including the axis of the stator core  10 . 
     The stator  1  includes a first region S 1  in which distal ends of the feeder lines  e U 1  to  e U 4 ,  e V 1  to  e V 4 ,  e W 1  to  e W 4  extending from the first ends of the plurality of coils U 1  to U 4 , V 1  to V 4 , W 1  to W 4  are connected to each other, and a second region S 2  in which distal ends of the neutral lines  c U 1  to  c U 4 ,  c V 1  to  c V 4 ,  c W 1  to  c W 4  extending from the second ends of the plurality of coils U 1  to U 4 , V 1  to V 4 , W 1  to W 4  are connected to each other. 
     The upper insulator  20  has an inner wall  20   a  and an outer wall  20   b  provided, spaced from each other in the radial direction of the stator core  10 . 
     In the cross section illustrated in  FIG.  6   , a center of gravity O 1  of the first region S 1  is positioned above a center of gravity O 2  of the second region S 2 , as seen in the axial direction of the stator core  10  (first condition). In other words, in the cross section illustrated in  FIG.  6   , the center of gravity O 2  of the second region S 2  is positioned between the center of gravity O 1  of the first region S 1  and the stator core  10  (first condition). In the first embodiment, a difference in height between the center of gravity O 1  of the first region S 1  and the center of gravity O 2  of the second region S 2  is denoted as H. The center of gravity O 1  of the first region S 1  here is a center of gravity of a cross-sectional shape of the first region S 1 , and the center of gravity O 2  of the second region S 2  is a center of gravity of a cross-sectional shape of the second region S 2 . 
     In the cross section illustrated in  FIG.  7   , when a radial length of the first region S 1  is denoted as B, a radial length of the second region S 2  is denoted as C, and a radial length between the inner wall  20   a  and the outer wall  20   b  of the upper insulator  20  is denoted as A, a relationship of 
     
       
         
           
             B &lt; A, and C &lt; A 
           
         
       
     
      is satisfied (second condition). 
     When the stator is used in a compressor  200 , as described later, satisfying the first condition and the second condition in the cross section at the gap between at least one pair of the plurality of coils U 1  to U 4 , V 1  to V 4 , W 1  to W 4 , taken along the plane including the axis of the stator core  10 , makes it possible to secure the passage cross-sectional area between the coils through which a refrigerant flows and thereby reduce the flow velocity of the refrigerant flowing between the coils and prevent oil from escaping through the gap between the coils. 
     In the first embodiment, the cross section at the gap between the pair of coils, taken along the plane including the axis of the stator core  10 , satisfies the first condition and the second condition. Across section at a gap between at least two coils, taken along a plane including the axis of the stator core  10 , should satisfy the first condition and the second condition. 
     Alternatively, cross sections at all gaps between adjacent ones of all the coils U 1  to U 4 , V 1  to V 4 , W 1  to W 4  taken along the plane including the axis of the stator core  10  may satisfy the first condition and the second condition. This makes it possible to secure the passage cross-sectional areas between all the coils U 1  to U 4 , V 1  to V 4 , W 1  to W 4 , to reduce the flow velocity of the refrigerant flowing between all the coils U 1  to U 4 , V 1  to V 4 , W 1  to W 4 , and thus to prevent an outflow of the oil from the gap between the coils U 1  to U 4 , V 1  to V 4 , W 1  to W 4 . 
     In a cross section of the stator core  10 , taken along a plane including the axis of the stator core  10 , at any point of the circumference of the stator core  10 , the center of gravity O 1  of the first region S 1  may be positioned above the center of gravity O 2  of the second region S 2 , as seen in the axial direction of the stator core  10 . In other words, in a cross section of the stator core  10 , taken along a plane including the axis of the stator core  10  and passing any point of the circumference of the stator core  10 , the center of gravity O 2  of the second region S 2  may be positioned between the center of gravity O 1  of the first region S 1  and the stator core  10 . As a result, the second region S 2  having a relatively small cross-sectional shape is, as a whole, located below the first region S 1  (i.e., closer to the stator core 10than the first region S 1 ), so that it is possible to make a space adjacent to the coil end larger, to thereby make the flow of the refrigerant smooth while making the passage cross-sectional area between the coils larger, and thus to reduce the flow velocity of the refrigerant flowing between the coils. 
     A lower end of the first region S 1  is preferably positioned above an upper end of the second region S 2 , as seen in the axial direction of the stator core  10 . In other words, it is preferable that an end remote from the stator core  10  of the second region S 2  be positioned between the stator core  10  and an end adjacent to the stator core  10  of the first region S 1 . As a result, the second region S 2  having a relatively small cross-sectional shape is located below the first region S 1  (i.e., closer to the stator core  10  than the first region S 1 ), so that it is possible to make the space adjacent to the coil end large, to thereby make the flow of the refrigerant smooth while making the passage cross-sectional area between the coils larger, and thus to reduce the flow velocity of the refrigerant flowing between the coils. 
     Next, details of the first region S 1  and the second region S 2  will be described. 
     First, in a top view of the stator  1  illustrated in  FIG.  5   , the lead wire  111  and the lead wire  121  are arranged on the coils U 1  to U 4 , V 1  to V 4 , W 1  to W 4  wound around each tooth  12 . The first region S 1  including the lead wires and the second region S 2  including the neutral lines vary in configuration, depending on their positions in the circumferential direction of the stator  1 . 
     For example, in the first region S 1  at a certain position in the circumferential direction of the stator  1 , the distal ends of the feeder lines  e U 1 ,  e U 2  ( FIGS.  3  and  4   ) extending from the first ends of the U-phase coils U 1 , U 2  are connected to the lead wire  111 , and the distal ends of the feeder lines  e U 3 ,  e U 4  ( FIGS.  3  and  4   ) extending from the first ends of the U-phase coils U 3 , U 4  are connected to the lead wire  121 . 
     Note that the connection part X Ua  ( FIGS.  3  and  4   ) where the feeder lines  e U 1 ,  e U 2  are connected to the lead wire  111  is covered with the insulating cap  110  having a roll shape. Note that the connection part X Ub  ( FIGS.  3  and  4   ) where the feeder lines  e U 3 ,  e U 4  are connected to the lead wire  121  is covered with the insulating cap  120  having a roll shape. 
     The feeder lines  e U 1 ,  e U 2 , the feeder lines  e U 3 ,  e U 4 , the lead wire  111 , and the lead wire  121  are fixed to the upper insulator  20  by a binding thread (not illustrated). 
     In the second region S 2 , the distal ends of the neutral lines  c U 1 ,  c U 2  ( FIGS.  3  and  4   ) extending from the second ends of the U-phase coils U 1 , U 2  are connected to the distal ends of the neutral lines  c U 3 ,  c U 4  ( FIGS.  3  and  4   ) extending from the second ends of the U-phase coils U 3 , U 4 . 
     Second Embodiment 
       FIG.  8    is a schematic cross-sectional view of an important part of a stator  1  of a second embodiment of the present disclosure. As illustrated in  FIG.  8   , in the cross section at the gap between adjacent ones of all the coils U 1  to U 4 , V 1  to V 4 , W 1  to W 4  taken along the plane including the axis of the stator core  10 , when a radial length from a radially innermost end to a radially outermost end of an aggregation of four first regions S 1  is denoted as La, and a radial length from a radially innermost end to a radially outermost end of an aggregation of two second regions S 2  is denoted as Lb, a relationship of 
     
       
         
           
             La &gt; Lb 
           
         
       
     
      is satisfied. 
     Satisfying the relationship of the expression 2 makes it possible to secure a passage cross-sectional area between the coils through which a refrigerant flows when the stator is used in a motor of a compressor. 
     The stator of the second embodiment has the same effects as the stator  1  of the first embodiment. 
     The present disclosure is applicable to not only the stator including the four first regions S 1  and the two second regions S 2  illustrated in  FIG.  8   , but also a stator including a plurality of first regions S 1  and at least one second region S 2 . 
     Third Embodiment 
       FIG.  9    is a cross-sectional view of a compressor  200  including a motor  240  of a third embodiment of the present disclosure. This compressor is a scroll compressor. 
     As illustrated in  FIG.  9   , the compressor  200  of the third embodiment includes a hermetic container, or vessel  201 , a compression mechanism part  230  including a fixed scroll  210  and a movable scroll  220 , a motor  240  that drives the compression mechanism part  230 , a crankshaft  250  that connects the compression mechanism part  230  to the motor  240 , and a lower bearing  260  that rotatably supports a lower end of the crankshaft  250 . 
     The hermetic container  201  includes a cylindrical member  202  that has a substantially cylindrical shape and is vertically opened, and an upper lid  203  and a lower lid  204  respectively provided at an upper end and a lower end of the cylindrical member  202 . 
     The motor  240  includes the stator  1  of the first embodiment and a rotor  2  disposed radially inside of the stator  1 . The motor  240  is of an inner rotor type and is a so-called 8-pole 12-slot motor. Note that the number of poles of the motor and the number of slots of the motor are not limited to those described above. 
     In the motor  240 , a plurality of lead wires from the stator  1  are connected to terminals of a terminal part  270  provided on the cylindrical member  202  of the hermetic container  201 . 
     An electromagnetic force produced in the stator  1  by applying a current to the coils U 1  to U 4 , V 1  to V 4 , W 1  to W 4  ( FIGS.  3  and  4   ) of the stator  1  of the motor  240  causes the rotor  2  to rotate together with the crankshaft  250 . 
     The use of the stator  1  of the first embodiment allows an increase in reliability of the motor  240  of the third embodiment. This makes the compressor  200  highly reliable. 
     In the third embodiment, the scroll compressor has been described. Alternatively, the motor of the present disclosure may be applied to a compressor having another configuration such as a rotary compressor. 
     In the first to third embodiments, the stator in which a three-phase AC voltage is applied to the coils has been described. Alternatively, the present disclosure may be applied to stators in which a two-phase or four- or more phase AC voltage is applied to the coils. 
     Although specific embodiments of the present disclosure have been described, the present disclosure is not limited to the first to third embodiments, and various modifications can be made within the scope of the present disclosure.