Patent Publication Number: US-2019195240-A1

Title: Electric compressor

Description:
TECHNICAL FIELD 
     The present disclosure relates to an electric compressor. 
     BACKGROUND ART 
     An electric compressor in which a compression unit and a motor are integrated is known. For example, Patent Literature 1 discloses an electric compressor for compressing a refrigerant which includes a housing for accommodating a motor, and a control circuit such as a motor drive circuit. The control circuit is mounted on a substrate plate, and the substrate plate is fixed to an outer surface of a peripheral wall of the housing. On the other hand, a suction path of a refrigerant gas serving as a refrigerant flow passage is present in the housing, and heat radiation fins protruding inward are provided on the peripheral wall of the housing. The heat radiation fins can increase a surface area for cooling the housing. 
     CITATION LIST 
     Patent Literature 
     Patent Literature 1: Japanese Unexamined Patent Publication No. 2002-174178 
     SUMMARY OF INVENTION 
     Technical Problem 
     However, in related art, although it is advantageous for cooling of the housing, there remains a problem in cooling of the control circuit indirectly cooled via the housing. 
     The present disclosure describes an electric compressor that can efficiently and effectively cool both the housing and the control circuit with a common refrigerant flow passage. 
     Solution to Problem 
     An aspect of the present disclosure is an electric compressor including: a motor which rotates a rotary shaft of an impeller; a housing which accommodates the motor; a plate attached to the housing and mounted with a control circuit configured to drive and control the motor; and a refrigerant flow passage provided between the housing and the plate. At least a part of the refrigerant flow passage is formed by a heat radiation fin provided on at least one of the housing and the plate. 
     Advantageous Effects of Invention 
     According to some aspects of the present disclosure, both the housing and the control circuit can be efficiently and effectively cooled by the common refrigerant flow passage. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a cross-sectional view of an electric compressor according to an embodiment of the present disclosure. 
         FIG. 2  is a cross-sectional view of the refrigerant flow passage according to the embodiment,  FIG. 2( a )  is a cross-sectional view taken along line II-II of  FIG. 1 , and  FIG. 2( b )  is a cross-sectional view taken along line b-b of  FIG. 2( a ) . 
         FIG. 3  is a view corresponding to  FIG. 2 , and is a cross-sectional view illustrating a first modified example of the refrigerant flow passage. 
         FIG. 4  is a view corresponding to  FIG. 2 , and is a cross-sectional view illustrating a second modified example of the refrigerant flow passage. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     An aspect of the present disclosure is an electric compressor which includes a motor which rotates a rotary shaft of an impeller, a housing which accommodates the motor, a plate which is attached to the housing and on which a control circuit configured to drive and control the motor is mounted, and a refrigerant flow passage provided between the housing and the plate, wherein at least a part of the refrigerant flow passage is formed by heat radiation fins provided on at least one of the housing and the plate. 
     In the electric compressor, since the refrigerant flow passage is formed between the housing and the plate, it is possible to efficiently and effectively cool both the control circuit mounted on the plate and the housing. Further, the refrigerant flow passage is formed by the heat radiation fins, and the heat radiation fins are provided on at least one of the housing and the plate. As a result, it is also possible to positively provide the heat radiation fins on a side desired to be preferentially cooled among the housing and the control circuit, and it is also possible to efficiently cool the housing and the control circuit. 
     In some embodiments, it is possible to provide the electric compressor in which the heat radiation fin is provided on both the housing and the plate. It is possible to more effectively cool both the housing and the control circuit mounted on the plate. 
     In some embodiments, it is possible to provide the electric compressor in which the heat radiation fins provided on the housing side and the heat radiation fins provided on the plate side are alternately arranged. The refrigerant flow passage is formed between the heat radiation fins and the heat radiation fins arranged alternately. As a result, it is advantageous for cooling of both the housing and the control circuit mounted on the plate without deviation. 
     In some embodiments, it is possible to provide the electric compressor which thither includes a pair of bearings disposed to sandwich the motor therebetween and supporting the rotary shaft, wherein the housing includes a partition wall between one bearing on the side closer to the plate among the pair of bearings and the plate, and a bearing support portion which supports the one bearing is provided inside the partition wall, and the refrigerant flow passage is provided outside the partition wall facing the bearing support portion. One bearing can also be effectively cooled via the bearing support portion. 
     In some embodiments, it is possible to provide the electric compressor in which the refrigerant flow passage is a one-pass meandering flow passage having a folded portion, and the folded portion curves. The curving of the folded portion makes it possible to prevent the retention of the refrigerant passing through the refrigerant flow passage. 
     In some embodiments, it is possible to provide the electric compressor in which the surface area facing the refrigerant flow passage is larger on the plate side than on the housing side. It is possible to effectively cool the control circuit mounted on the plate. 
     Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings. Incidentally, in the description of the drawings, the same elements are denoted by the same reference numerals, and repeated description will not be provided. 
     An electric compressor  1  according to an embodiment will be described with reference to  FIG. 1 . As illustrated in  FIG. 1 , the electric compressor  1  is applied to, for example, an internal combustion engine of a vehicle or a ship. The electric compressor  1  is provided with a compressor  7 . The electric compressor  1  rotates a compressor impeller (an example of an impeller)  8  by an interaction between a rotor unit  13  and a stator unit  14  to compress a fluid such as air and to generate compressed air. A motor  5  is formed by the rotor unit  13  and the stator unit  14 . 
     The electric compressor  1  includes a rotary shaft  12  rotatably supported within a housing  2 , and the compressor impeller  8  fixed to a front end portion (one end portion)  12   a  of the rotary shaft  12 . The housing  2  includes a motor housing  3  that houses the motor  5  (the rotor unit  13  and the stator unit  14 ), and an inverter housing  4  that closes an opening of the other end side (a right side in the drawing) of the motor housing  3 . A compressor housing  6  which accommodates the compressor impeller  8  is provided on one end side (a left side in the drawing) of the motor housing  3 . The compressor housing  6  includes a suction port  9 , a scroll portion  10 , and a discharge port  11 . 
     The rotor unit  13  is fixed to a central portion of the rotary shaft  12  in an axial direction, and includes one or a plurality of permanent magnets (not illustrated) attached to the rotary shaft  12 . The stator unit  14  is fixed to an inner surface of the motor housing  3  to surround the rotor unit  13 , and includes a coil portion (not illustrated) in which a conductive wire is wound. When an alternating current flows in the coil portion of the stator unit  14  through the conductive wire, the rotary shaft  12  and the compressor impeller  8  rotate integrally due to the interaction between the rotor unit  13  and the stator unit  14 . When the compressor impeller  8  rotates, the compressor impeller  8  sucks outside air through the suction port  9 , compresses the air through the scroll portion  10 , and discharges the air from the discharge port  11 . The compressed air discharged from the discharge port  11  is supplied to the aforementioned internal combustion engine. 
     The electric compressor  1  includes two bearings  20 A and  20 B that rotatably support the rotary shaft  12  with respect to the housing  2 . The bearings  20 A and  20 B are attached to the rotary shaft  12  by, for example, press-fitting or fitting with a gap. The bearings  20 A and  20 B are disposed to sandwich the motor  5 , and support the rotary shaft  12  by holding two points. One bearing  20 A is provided at the end portion of the motor housing  3  on the compressor impeller  8  side. The other bearing  20 B is provided on a support wall portion  23  that protrudes from the inverter housing  4  in the axial direction of the rotary shaft  12 . 
     The inverter housing  4  is provided with a mechanism for supplying a driving current to the stator unit  14 . The inverter housing  4  includes a disc-shaped end wall portion (an example of a partition wall)  21  that closes an opening on the other end side of the motor housing  3 , and a peripheral wall portion  22  that connects the outer peripheral portion of the end wall portion  21  and the motor housing  3 . A conductive wire  14   a  connected to the stator unit  14  is accommodated in the peripheral wall portion  22 . The end wall portion  21  is made of, for example, aluminum, but stainless steel or carbon steel can also be adopted. 
     The above-described support wall portion (an example of the bearing support portion)  23  has a base portion  41  protruding from the center of the end wall portion  21  toward the inner side of the rotary shaft  12  in the axial direction, a tubular sleeve receiver  42  further protruding inward from the base portion  41 , and a sleeve  43  mounted on the outer periphery of the sleeve receiver  42 . An outer ring  51  of the bearing  20 B is attached to the sleeve  43  by fitting. 
     A module plate  31  is fixed on a side opposite to the inner side of the end wall portion  21 , that is, on the outer side the rotary shaft  12  in the axial direction. On the module plate  31 , a module (an example of a control circuit)  32  which accommodates a control unit such as an inverter is mounted. A driving control of the electric motor is performed by the control unit of the module  32 . A bus bar  33  is connected to the conductive wire  14   a.  The bus bar  33  penetrates the end wall portion  21  and is connected to the module  32 . The bus bar  33  is a conductive member for supplying a driving current, and is made of, for example, copper. Incidentally, as the module plate  31 , aluminum, copper, and other metal plates can be adopted. 
     A refrigerant flow passage  60  is formed between the module plate  31  and the end wall portion  21 . More specifically, the support wall portion  23  which supports the bearing  20 B is provided inside the end wall portion  21 . The refrigerant flow passage  60  is provided between the end wall portion  21  facing the support wall portion  23  and the module plate  31 . The inner sides of the module  32  of the module plate  31  and the inverter housing  4  are cooled by a refrigerant Re (for example, refrigerant gas) passing through the refrigerant flow passage  60 . An inlet  61  and an outlet  62  (see  FIG. 2 ) exist in the refrigerant flow passage  60 . An inlet pipe  61   a  of the refrigerant flow passage  60  is connected to the inlet  61 , and a discharge pipe  62   a  of the refrigerant flow passage  60  is connected to the outlet  62 . Further, the discharge pipe  62   a  may be connected to a refrigerant flow passage  3   a  of the motor housing  3 . In this case, for example, the refrigerant Re passes through the refrigerant flow passage  60  of the inverter housing  4 , and thereafter is introduced into the refrigerant flow passage  3   a  of the motor housing  3 . 
     As illustrated in  FIG. 2 , the module plate  31  is disposed to close the refrigerant flow passage  60 . In the present embodiment, the refrigerant flow passage  60  that connects the single inlet  61  and the single outlet  62  in one pass will be described as an example. However, for example, an aspect may be adopted in which the refrigerant flow passage  60  branches from the single inlet  61  into a plurality of flow passages and is connected to a plurality of outlets  62 . Further, an aspect may be adopted in which the refrigerant flow passage  60  is integrated into a single flow passage from a plurality of inlets  61  and connected to a single outlet  62 . Further, an aspect may be adopted in which the plurality of inlets  61  and the plurality of outlets  62  are connected to each other. Furthermore, the refrigerant flow passage  60  may be the plurality of independent flow passages. 
     The refrigerant flow passage  60  is formed by a substantially rectangular recess  63  formed in the inverter housing  4  and heat radiation fins  64 A and MB arranged in the recess  63 . Further, the inlet  61  and the outlet  62  of the refrigerant Re are formed in the inverter housing  4 . Further, in the inverter housing  4 , a seal groove  4   a  is formed to surround the recess  63 . A seal member  4   b  such as an O-ring is mounted in the seal groove. The seal member  4   b  is sandwiched between the inverter housing  4  and the module plate  31  by crimping, thereby maintaining the airtightness (or liquid tightness) of the refrigerant flow passage  60 . 
     A plurality of heat radiation fins  64 A and  64 B are disposed in the recess  63 . A part of the plurality of heat radiation fins  64 A and  64 B protrudes from the inverter housing  4 , and the other thereof protrudes from the module plate  31 . In this embodiment, for example, three heat radiation fins  64 A and  64 B are juxtaposed and the central heat radiation fin is the heat radiation fin  64 A on the inverter housing  4  side. Further, the two heat radiation fins disposed to face each other to sandwich the central heat radiation fin  64 A are heat radiation fins  64 B on the module plate  31  side. That is, in the present embodiment, the heat radiation fins  64 A on the inverter housing  4  side and the heat radiation fins  64 B on the module plate  31  side are alternately arranged. 
     By arranging the plurality of heat radiation fins  64 A and  64 B in parallel, the refrigerant flow passage  60  is formed between the heat radiation fins  64 A and  64 B. For example, the refrigerant flow passage  60  has three folded portions  60   a  that go around along the end portions  64   a  of the heat radiation fins  64 A and  64 B to form meandering flow passages (see  FIG. 2( a ) ). Further, the inlet  61  of the refrigerant Re is provided at one end portion of the refrigerant flow passage  60 , and the outlet  62  is provided at the other end portion. As a result, the refrigerant flow passage  60  is a single (one-pass) flow passage. Further, in this embodiment, the folded portion  60   a  curves to prevent retention of the refrigerant Re. More specifically, the outer peripheral portion  60   b  of the folded portion  60   a  is a part of the recess  63 , and a part thereof is a recessed curved surface. 
     The plurality of heat radiation fins  64 A and  64 B according to the present embodiment are provided on both the inverter housing  4  and the module plate  31 . As a result, it is possible to more effectively cool both the inverter housing  4  and the module  32  mounted on the module plate  31 . In particular, in the present embodiment, the heat radiation fins  64 A on the inverter housing  4  side and the heat radiation fins  64 B on the module plate  31  side are alternately arranged, and the refrigerant flow passage  60  is formed between the heat radiation fins  64 A and the heat radiation fins  64 B alternately arranged. As a result, it is advantageous in cooling both the inverter housing  4  and the module  32  mounted on the module plate  31  without deviation. 
     Further, in the present embodiment, the number of the heat radiation fins  64 B on the module plate  31  side is larger than the number of the heat radiation fins  64 A on the inverter housing  4  side. That is, the surface area facing the refrigerant flow passage  60  is larger on the module plate  31  side than on the inverter housing  4  side. As a result, it is advantageous in preferentially and effectively cooling the module  32  mounted on the module plate  31 . 
     Further, the end wall portion  21  according to the present embodiment partitions between the bearing  20 B, which is on the side close to the module plate  31  among the pair of bearings  20 A and  20 B, and the module plate  31 . Here, the support wall portion  23  which supports the bearing  20 B is provided inside the end wall portion  21 . The refrigerant flow passage  60  is provided on the outer side of the end wall portion  21  facing the support wall portion  23  so as to overlap the support wall portion  23 . In this case, the bearing  20 B can also be effectively cooled via the support wall portion  23 . 
     Next, first and second modified examples of the refrigerant flow passage  60  will be described with reference to  FIGS. 3 and 4 . Incidentally, in the first and second modified examples, elements and structures common to those of the above-described refrigerant flow passage  60  are denoted by the same reference numerals, a description thereof will not be provided, and differences will be mainly described. 
     The refrigerant flow passage  60  according to the first and second modified examples is a meandering flow passage of one pass as described above, and is formed by the plurality of heat radiation fins  64 A and  64 B arranged in the recess  63  of the inverter housing  4 . Here, all of the heat radiation fins of the refrigerant flow passage  60  according to the first modified example are the heat radiation fins  64 B on the module plate  31  side. Further, the heat radiation fins of the refrigerant flow passage  60  according to the second modified example are all the heat radiation fins  64 A on the inverter housing  4  side. 
     As in the first modified example, by using all of the heat radiation fins as the heat radiation fins  64 B on the module plate  31  side, it is more advantageous in cooling of the module  32 . On the other hand, as in the second modified example, by using all of the heat radiation fins as the heat radiation fins  64 A on the inverter housing  4  side, it is more advantageous in cooling of the inside of the inverter housing  4  and the inverter housing  4 . 
     The above-described electric compressor  1  is provided with the common refrigerant flow passage  60  formed between the inverter housing  4  (a part of the housing  2 ) and the module plate  31 . With the refrigerant flow passage  60 , it is possible to efficiently and effectively cool both the inverter housing  4  and the module  32  mounted on the module plate  31 . Further, the refrigerant flow passage  60  is formed by the heat radiation fins  64 A and  64 B, and the heat radiation fins  64 A and  64 B are provided on at least one of the inverter housing  4  and the module plate  31 . As a result, it is also possible to positively provide the heat radiation fins  64 A and  64 B on a side desired to be preferentially cooled among the inverter housing  4  and the module  32 , and it is possible to efficiently cool the inverter housing  4  and the module  32 . 
     The present disclosure can be implemented in various forms including various modifications and improvements based on knowledge of those skilled in the art, including the above-described embodiments. Further, it is also possible to constitute a modified example of each embodiment, using the technical matters described in the above embodiment. The configurations of the embodiments may be combined as appropriate. 
     Further, the present disclosure is not limited to those applied to electric compressors for automobiles, but may be applied to vessels and the like. 
     REFERENCE SIGNS LIST 
       1 : electric compressor,  2 : housing,  4 : inverter housing,  5 : motor,  8 : compressor impeller (impeller),  12 : rotary shaft,  20 A,  20 B: bearing,  21 : end wall portion (partition wall),  23 : support wall portion (bearing support portion),  31 : module plate (plate),  60 : refrigerant flow passage,  60   a : folded portion,  64 A,  64 B: heat radiation fin.