Patent Publication Number: US-2010129238-A1

Title: Inverter-integrated electric compressor and coil component for inverter thereof

Description:
TECHNICAL FIELD 
     The present invention relates to an inverter-integrated electric compressor, having an integrated inverter, suitable for use in a compressor for an air conditioner installed in a vehicle and also to a coil component for the inverter. 
     BACKGROUND ART 
     Various inverter-integrated electric compressors having integrated inverters have recently been proposed as compressors for air conditioners installed in vehicles. In a typical inverter-integrated electric compressor for vehicle air conditioners, an inverter-accommodating section (inverter box) is disposed on the periphery of a housing into which an electric motor and a compression mechanism are built, and an inverter is installed in the inverter-accommodating section to convert DC power supplied from a high-voltage power supply into three-phase AC power and supply the power to the electric motor so that the rotational speed of the electric compressor can be changed depending on the air-conditioning load. 
     Such an inverter includes high-voltage components, such as a smoothing capacitor (capacitor), an inductor coil, and a common-mode coil, as its components (see, for example, Patent Document 1). Of these high-voltage components, the smoothing capacitor (capacitor) is typically protected by a metal outer case (see, for example, Patent Document 2), whereas coil components such as the inductor coil and the common-mode coil are often constructed merely by winding enamel-insulated wires. To install such coil components in an inverter-accommodating section formed of an aluminum alloy, therefore, they must be insulated from the inverter-accommodating section. Currently the coil components are installed in the inverter-accommodating section with, for example, insulating silicone sheets laid therein. 
     Patent Document 1: 
     The Publication of Japanese Patent No. 3827158 
     Patent Document 2: 
     Japanese Unexamined Patent Application, Publication No. 2006-196680 
     DISCLOSURE OF INVENTION 
     Problems to be Solved by the Invention 
     However, if the coil components are installed in the inverter-accommodating section with, for example, insulating silicone sheets laid therein, as described above, the coil components must be installed by applying an adhesive to sites where the coil components are to be installed in the inverter-accommodating section, laying the insulating silicone sheets, pouring a silicone adhesive therein, and inserting and placing the coil components on the insulating silicone sheets. Hence this method has a problem in that the ease of installation of the coil components is poor and that the silicone sheets have inferior strength and durability and are also expensive. 
     An object of the present invention, which has been made in light of such circumstances, is to provide an inverter-integrated electric compressor capable of achieving improved ease of installation of a coil component constituting an inverter and increased strength and reduced cost of an insulating member, and also to provide a coil component for the inverter. 
     To solve the above problems, an inverter-integrated electric compressor of the present invention and a coil component for the inverter employ the following solutions. 
     That is, in an inverter-integrated electric compressor according to the present invention, an inverter-accommodating section is disposed on the periphery of a housing into which an electric motor and a compression mechanism are built, and an inverter is accommodated and installed in the inverter-accommodating section to convert DC power into three-phase AC power and supply the power to the electric motor. The inverter-integrated electric compressor includes a resin spacer member having a molded shape surrounding at least the bottom of a coil component constituting the inverter to ensure an insulation distance between the coil component and the inverter-accommodating section when installed in the inverter-accommodating section, and the coil component is fixed to and installed in the inverter-accommodating section with the resin spacer member disposed therebetween. 
     According to the present invention, the resin spacer member is installed in the inverter-accommodating section, having a molded shape surrounding at least the bottom of the coil component to ensure the insulation distance between the coil component and the inverter-accommodating section when installed in the inverter-accommodating section. The coil component can therefore be fixed to and installed in the inverter-accommodating section with the resin spacer member disposed therebetween so as to surround at least the bottom of the coil component. This improves the ease of installation of the coil component. It is also possible to increase the strength and reduce costs as compared with conventional silicone sheets because the insulating member can be constituted of a spacer member formed of a resin. 
     An inverter-integrated electric compressor of the present invention may be configured such that, in the above inverter-integrated electric compressor, the coil component is fixed to and installed in the inverter-accommodating section by fixing the coil component and the resin spacer member together and fixing the resin spacer member and the inverter-accommodating section together. 
     According to this configuration, because the coil component is fixed to and installed in the inverter-accommodating section by fixing the coil component and the resin spacer member together and fixing the resin spacer member and the inverter-accommodating section together by means of, for example, an adhesive or by tight fitting, the coil component, the resin spacer member, and the inverter-accommodating section can be fixed so that no relative displacement occurs between these three components. The coil component can thus be installed stably against, for example, vibrations. 
     An inverter-integrated electric compressor of the present invention may be configured such that, in one of the above inverter-integrated electric compressors, the resin spacer member has a hole or gap through which an adhesive can pass. 
     According to this configuration, because the resin spacer member has the hole or gap through which an adhesive can pass, the resin spacer member and the coil component can be fixed together at the same time by allowing an adhesive for fixing and installing the resin spacer member to enter the interior thereof through the hole or gap. This further improves the ease of installation of the coil component. 
     An inverter-integrated electric compressor of the present invention may be configured such that, in the above inverter-integrated electric compressor, the coil component and the resin spacer member are integrated by resin molding. 
     According to this configuration, because the coil component and the resin spacer member are integrated by resin molding, the coil component can be fixed to and installed in the inverter-accommodating section with the resin spacer member integrated with the coil component. This further improves the ease of installation of the coil component. 
     An inverter-integrated electric compressor of the present invention may be configured such that, in one of the above inverter-integrated electric compressors, the resin spacer member is formed of a molded product of a resin such as polyethylene terephthalate or polybutylene terephthalate. 
     According to this configuration, because the resin spacer member is formed of a resin-molded product of polyethylene terephthalate or polybutylene terephthalate, the properties of the material can be utilized to enhance the intrinsic function of the resin spacer member, namely, the function of providing insulation between the coil component and the inverter-accommodating section. In addition, the insulating spacer member can be produced at low cost because the material itself is less expensive. 
     A coil component for an inverter according to the present invention is a coil component, such as an inductor coil or a common-mode coil, for use in an inverter of an electric compressor. The coil component is fitted into a resin spacer member having a molded shape surrounding at least the bottom of the coil component and is integrated therewith by resin molding. 
     According to the present invention, because the coil component is fitted into the resin spacer member having a molded shape surrounding at least the bottom of the coil component and is integrated therewith by resin molding, no additional insulation measure is needed when the coil component, such as an inductor coil or a common-mode coil, constituting the inverter is mounted at a mounting point on a conductive member, thus simplifying the installation of the coil component and improving ease of installation. 
     According to the present invention, the resin spacer member has a molded shape surrounding at least the bottom of the coil component, and the coil component can be fixed to and installed in the inverter-accommodating section with the resin spacer member disposed therebetween so as to surround at least the bottom of the coil component. This improves the ease of installation of the coil component and also increases the strength and reduces costs as compared with conventional silicone sheets because the insulating member can be constituted of a spacer member formed of a resin. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a partial longitudinal sectional view showing, in cutaway view, an inverter-accommodating section of an inverter-integrated electric compressor according to a first embodiment of the present invention. 
         FIG. 2  is a plan view showing, in cutaway view, part of the inverter-accommodating section of the inverter-integrated electric compressor shown in  FIG. 1 . 
         FIG. 3  is a plan view of a resin spacer member used for installation of a coil component in the inverter-integrated electric compressor shown in  FIG. 1 . and a right side view (B) and a bottom view (C). 
         FIG. 3B  is a right side view of the resin spacer member used for installation of a coil component in the inverter-integrated electric compressor shown in  FIG. 1 . 
         FIG. 3C  is a bottom view of the resin spacer member used for installation of a coil component in the inverter-integrated electric compressor shown in  FIG. 1 . 
         FIG. 4A  is a perspective view of another form of resin spacer member used for installation of a coil component in an inverter-integrated electric compressor according to a third embodiment of the present invention. 
         FIG. 4B  is a perspective view of another form of resin spacer member used for installation of a coil component in the inverter-integrated electric compressor according to the third embodiment of the present invention. 
         FIG. 4C  is a perspective view of another form of resin spacer member used for installation of a coil component in the inverter-integrated electric compressor according to the third embodiment of the present invention. 
         FIG. 4D  is a perspective view of another form of resin spacer member used for installation of a coil component in the inverter-integrated electric compressor according to the third embodiment of the present invention. 
     
    
    
     EXPLANATION OF REFERENCE SIGNS 
     
         
           1 : inverter-integrated electric compressor 
           2 : housing 
           9 : electric motor 
           11 : inverter-accommodating section 
           20 : inverter 
           22 : inductor coil (coil component) 
           26 ,  36 ,  46 ,  56 , and  66 : resin spacer member 
           26 H: hole 
       
    
     BEST MODE FOR CARRYING OUT THE INVENTION 
     Embodiments of the present invention will be described below with reference to the drawings. 
     First Embodiment 
     A first embodiment of the present invention will now be described using  FIGS. 1 ,  2 , and  3 A to  3 C. 
       FIG. 1  is a partial longitudinal sectional view showing, in cutaway view, an inverter-accommodating section of an inverter-integrated electric compressor according to the first embodiment of the present invention;  FIG. 2  is a plan view showing part of it in cutaway view. An inverter-integrated electric compressor  1  includes a housing  2  forming the outer structure thereof. The housing  2  is constituted by fastening together a motor housing  3  accommodating an electric motor  9  and a compressor housing  4  accommodating a compression mechanism (not shown) with bolts  5 . The motor housing  3  and the compressor housing  4  are formed of aluminum die castings. 
     The electric motor  9  and the compression mechanism (not shown) built into the housing  2  are coupled together via a motor shaft  10  (see  FIG. 1 ) so that the compression mechanism is driven as the electric motor  9  rotates. A refrigerant suction port  6  (see  FIG. 2 ) is provided at one end of the motor housing  3  (to the right of  FIG. 1 ), and a low-temperature, low-pressure refrigerant gas taken into the motor housing  3  through the refrigerant suction port  6  flows beside the electric motor  9  in the direction of a motor axis L and is taken into and compressed by the compression mechanism. The high-temperature, high-pressure refrigerant gas compressed by the compression mechanism is discharged into the compressor housing  4  and is sent outside through a discharge port  7  provided at one end of the compressor housing  4  (to the left of  FIG. 1 ). 
     The housing  2  has attachment legs  8 A,  8 B, and  8 C at three positions: two on the bottom of one end of the motor housing  3  (to the right of  FIG. 1 ) and on the bottom of one end of the compressor housing  4  (to the left of  FIG. 1 ), and one on the top of the compressor housing  4 . The inverter-integrated electric compressor  1  is mounted by fastening the attachment legs  8 A,  8 B, and  8 C with brackets and bolts to, for example, a sidewall of a running motor installed in an engine room of a vehicle. The inverter-integrated electric compressor  1  is usually supported at three top and bottom positions with fastening brackets on one side thereof, the direction of the motor axis L pointing in the front-to-back or left-to-right direction of the vehicle. 
     In addition, a box-shaped inverter-accommodating section  11  is integrally formed on the top of the periphery of the motor housing  3 .  FIG. 1  is a partial longitudinal sectional view showing the inverter-accommodating section  11  in cutaway view. The inverter-accommodating section  11 , as shown in  FIGS. 1 and 2 , has a box structure constituted of surrounding walls of predetermined height with its top side open, and the top opening is sealed by fastening a cover member  18  using screws  19  with a sealant (not shown) therebetween. The inverter-accommodating section  11  has two power-cable routing holes  12  and  13  on one side thereof so that a high-voltage power supply can be connected to an inverter  20  installed in the inverter-accommodating section  11  via two P-N power cables  14  and  15 . 
     The inverter  20  installed in the inverter-accommodating section  11  is constituted of P-N terminals (not shown) to which the power cables are connected; high-voltage components disposed in the power line, including a smoothing capacitor (capacitor)  21  as well as an inductor coil  22  and a common-mode coil (not shown) (hereinafter simply referred to as coil components  22 ); an inverter module  23  constituting the principle part of the inverter  20 ; a bus-bar assembly  24  including a plurality of bus bars, for electrical wiring in the inverter  20 , integrated by insert molding using an insulating resin; glass-sealed terminals  25  for supplying the electric motor  9  with three-phase AC power output from the inverter  20  after conversion; and so on. 
     The above inverter module  23  is constituted by integrating into a module a power substrate on which a plurality of power semiconductor switching devices (power devices such as IGBTs) and a power control circuit for operating them are mounted and a CPU substrate on which control and communication circuits having devices that operate with low voltage, such as a CPU, are mounted (not shown). 
     In general, the coil components  22  used in the inverter  20  are often constructed merely by winding enamel-insulated wires. To install such coil components  22  in the inverter-accommodating section  11 , which is formed of an aluminum die casting, they must be insulated from the inverter-accommodating section  11 . In this embodiment, therefore, the coil components  22  are installed by means of resin spacer members (case members)  26  formed of a resin such as polyethylene terephthalate (PET) or polybutylene terephthalate (PBT). 
     The resin spacer members (case members)  26  have a molded shape surrounding at least the bottoms of the coil components  22  so that they can ensure the required insulation distance between the coil components  22  and the inverter-accommodating section  11  when installed in the inverter-accommodating section  11 . Referring to  FIGS. 3A to 3C , specifically, the resin spacer members (case members)  26  are formed in the shape of a case in which substantially the lower halves of the coil components  22 , which have a cylindrical shape, can be fitted. That is, the resin spacer members (case members)  26  are formed in a case shape with a rectangular cross-section whose top surface is constituted by an opening plane  26 A and whose wall surfaces are constituted by four side surfaces  26 B to  26 E and a bottom surface  26 F, having smoothly curved surfaces at the two lower corners. 
     The resin spacer members (case members)  26  have ribs  26 G extending vertically across the individual side surfaces  26 B to  26 E to ensure sufficient strength and an appropriate number of holes  26 H in the side surfaces  26 B and  26 C (two for each side surface in this embodiment) so that an adhesive can enter the interiors of the case-shaped resin spacer members  26 . Forming the holes  26 H has no effect on ensuring the insulation distance. 
     After the inverter  20  is installed in the inverter-accommodating section  11 , its inner space is filled with a vibration-proofing, moisture-proofing potting gel  27  with an air layer of certain size left on its top side to accommodate thermal expansion. The inverter-accommodating section  11  is configured such that it is sealed with the cover member  18  after being filled with the potting gel  27 . 
     According to this embodiment, the configuration described above has the following effects and advantages. 
     The above inverter-integrated electric compressor  1  operates as follows. The inverter  20  converts DC power supplied from the high-voltage power supply via the power cables  14  and  15  into three-phase AC power of predetermined frequency corresponding to the air conditioning load and supplies the power to the electric motor  9  via the glass-sealed terminals  25 , so that the electric motor  9  can rotate. The compression mechanism is thus driven, thereby compressing a low-temperature, low-pressure refrigerant gas taken through the refrigerant suction port  6  provided at one end of the motor housing  3  to a high-temperature, high-pressure state. This high-temperature, high-pressure compressed gas is discharged into the compressor housing  4  and is sent from there to the outside through the discharge port  7 . 
     The low-temperature, low-pressure refrigerant gas taken into the housing  2  through the refrigerant suction port  6  is drawn into a space between one end of the motor housing  3  and the electric motor  9 , flows from there into the compressor housing  4  past the stator periphery of the electric motor  9 , and is drawn into the compression mechanism. Meanwhile, the exothermic devices used as the components of the inverter  20  installed in the inverter-accommodating section  11 , including the power devices such as IGBTs, the smoothing capacitor (capacitor)  21 , and the inductor coil  22 , are cooled from inside the housing  2  via the circumferential wall of the motor housing  3 . 
     In the installation of the inverter  20 , additionally, the coil components  22 , such as the inductor coil and the common-mode coil, can be installed by fixing and installing the resin spacer members (case members)  26  in the inverter-accommodating section  11  with a silicone adhesive and inserting the coil components  22  therein. The coil components  22  are then fixed to the resin spacer members  26  with the silicone adhesive for fixing the resin spacer members  26  that has entered the interiors of the resin spacer members  26  through the holes  26 H, if necessary, in combination with a silicone adhesive injected into the resin spacer members  26 . After the installation of the inverter  20  is thus completed, the inverter-accommodating section  11  is filled with the vibration-proofing, moisture-proofing potting gel  27  and is sealed with the cover member  18 . 
     According to this embodiment, the coil components  22 , which are inserted into the resin spacer members (case members)  26 , can be fixed to and installed in the inverter-accommodating section  11  with the resin spacer members  26  disposed therebetween so as to ensure the required insulation distance. This improves the ease of installation of the coil components  22  as compared with a conventional method in which the coil components  22  are installed by laying insulating sheets and placing the coil components  22  thereon. It is also possible to significantly increase the strength and reduce costs as compared with conventional silicone sheets because the insulating members can be constituted of the spacer members  26 , which are formed of a resin. 
     In addition, the coil components  22  can be fixed and installed stably against, for example, vibrations because the coil components  22 , the resin spacer members  26 , and the inverter-accommodating section  11  are fixed to each other with an adhesive. In addition, the coil components  22  can be fixed to the resin spacer members  26  with the adhesive for fixing the resin spacer members  26  because the adhesive can enter the interiors thereof through the holes  26 H provided in the resin spacer members  26 . This enables efficient installation of the coil components  22 , thus improving the ease of installation. Instead of the adhesive, the coil components  22  can be fixed to the resin spacer members  26  mechanically, such as by tight fitting. 
     In addition, because the resin spacer members (case members)  26  are formed of molded products of a resin such as polyethylene terephthalate or polybutylene terephthalate, the properties of the material can be utilized to enhance the intrinsic function of the resin spacer members  26 , namely, the function of providing insulation between the coil components  22  and the inverter-accommodating section  11 . In addition, the insulating spacer members  26  can be produced at low cost because the material itself is less expensive. 
     Second Embodiment 
     Next, a second embodiment of the present invention will be described. 
     This embodiment differs from the first embodiment described above in the configuration of the coil components  22 . The other features are identical to those of the first embodiment, and therefore a description thereof will be omitted. 
     In this embodiment, the coil components  22  and the resin spacer members (case members)  26 , which have a molded shape surrounding at least the bottoms thereof, are integrated by resin molding in advance. 
     If the coil components  22  and the resin spacer members  26  are integrated by resin molding in advance, as described above, the coil components  22  can be installed in the inverter-accommodating section  11  by fixing and installing the resin spacer members  26  integrated with the coil components  22  in the inverter-accommodating section  11 . Thus, the use of the coil components  22  integrated with the insulating resin spacer members  26  by molding further improves the ease of installation of the coil components  22 . 
     Third Embodiment 
     Next, a third embodiment of the present invention will be described using  FIGS. 4A to 4D . 
     This embodiment differs from the first and second embodiments described above in the configuration of the resin spacer members  26 . The other features are identical to those of the first and second embodiments, and therefore a description thereof will be omitted. 
     In this embodiment, the resin spacer members have modified shapes as shown in  FIGS. 4A to 4D .  FIG. 4A  shows a meshed, semicircular resin spacer member  36 .  FIG. 4B  shows a meshed, basket-shaped resin spacer member  46 .  FIG. 4C  shows a resin spacer member  56  composed of a pair of left and right cup-shaped members  56 A and  56 B with the coil components  22  held between the sides thereof.  FIG. 4D  shows a cup-shaped resin spacer member  66  having an opening on one side thereof. 
     The same effects and advantages as the first and second embodiments described above can also be achieved using the resin spacer members  36 ,  46 ,  56 , and  66 , which have the shapes described above so that they can surround at least the bottoms of the coil components  22 . The resin spacer members permit various other modifications. 
     The present invention is not limited to the invention according to the above embodiments; modifications are permitted as needed without departing from the spirit thereof. The compression mechanism provided in the compressor housing  4 , for example, may be any type of compression mechanism, such as a rotary type, a scroll type, or a swash-plate type, and is not particularly limited. In addition, the inverter  20  and its placement and configuration are not limited to the above embodiments, and various modifications are permitted, including installing the smoothing capacitor (capacitor)  21  and the inductor coil  22  on the side surfaces of the inverter-accommodating section  11  (on the back surface in the above embodiments). In addition, the material of the resin spacer members is not limited to PET and PBT, as described above, and resins with similar properties can be used.