Electric Compressor

The present invention relates to an electric compressor mounted on a predetermined object such as a vehicle.

Patent Literature 1 discloses an electric compressor including an electric motor, a compression mechanism driven by the electric motor, an inverter that drives the electric motor, and a housing (in the following, referred to as a casing) that houses these components. The electric compressor is mounted on the vehicle via a mounting portion including a first mounting leg, a second mounting leg, and a third mounting leg. The first mounting leg and the second mounting leg are provided integrally with the peripheral wall of the motor casing of the casing, and the third mounting leg is provided on a cover on the inverter side of the casing. In the electric compressor, a stator of the electric motor is generally incorporated in the inside of the casing by shrink fitting. During the shrink fitting, the casing is heated.

Patent Document 1: Japanese Patent No. 6955220

However, in the electric compressor disclosed in Patent Literature 1, since the first mounting leg and the second mounting leg are provided integrally with the motor casing, the first mounting leg and the second mounting leg are heated together with the motor casing when the stator is shrink fitted. As a result, the first mounting leg and the second mounting leg are deformed, and the position accuracy of the mounting portion might deteriorate due to the assembly of a stator.

The present invention has been made to solve the above problems, and an object of the present invention is to provide an electric compressor having a structure capable of stopping a decrease in position accuracy of a mounting portion due to the assembly of a stator.

An electric compressor according to the present invention includes an electric motor, a compression mechanism driven by the electric motor, an inverter that drives the electric motor, a casing in which the electric motor, the compression mechanism, and the inverter are housed, and a mounting portion that is formed in the casing and mounts the casing on a predetermined object. In the electric compressor, the casing includes a motor casing in which the electric motor is housed, a compression mechanism casing in which the compression mechanism is housed, and an inverter casing in which the inverter is housed, and the mounting portion includes a first mounting leg provided in the compression mechanism casing and a second mounting leg provided in the inverter casing.

According to the present invention, it is possible to provide an electric compressor having a structure capable of stopping deterioration in position accuracy of a mounting portion due to the assembly of a stator.

In the following, an embodiment of an electric compressor according to the present invention will be described with reference to the drawings.

are diagrams for explaining an electric compressoraccording to an embodiment of the present invention. Specifically,is an exploded perspective view of the electric compressor,is a perspective view of the electric compressor, andis a conceptual diagram for explaining an example of a state when the electric compressoris mounted on a predetermined object C.is a partially schematic sectional view.

The electric compressoris mounted on a vehicle as a part of a vehicle air conditioner, for example, and is used as a device that sucks, compresses, and discharges a refrigerant for vehicle air conditioning. The electric compressoris mounted on a part of a vehicle body of a vehicle in an engine room of the vehicle, for example. That is, in the present embodiment, the object C on which the electric compressoris mounted is a part of the vehicle body.

Referring to, the electric compressorincludes an electric motor, a compression mechanismdriven by the electric motor, an inverterthat drives the electric motor, a casingin which the electric motor, the compression mechanism, and the inverterare housed, and a mounting portion. That is, the electric compressoris configured as a so-called inverter-integrated electric compressor.

Referring to, the electric motorincludes a statorin an annular shape, a rotor, and a coil (not shown) wound around the stator. As the electric motor, for example, a three-phase AC motor is applied.

The statoris formed in an annular shape. The statoris made of, for example, a plurality of silicon steel plates laminated on each other.

The rotoris disposed radially inside the statorand has a plurality of magnetic poles (not shown). Into a through hole formed at the radial center of the rotor, a rotating shaftis fitted. The rotating shaftis provided integrally with the rotor. The longitudinal ends of the rotating shaftsare rotatably supported inside the casing. The rotoris rotatably supported on the radially inner side of the statorvia the rotating shaft. When a magnetic field is generated in the statorby the power supply from the inverter, a rotational force acts on the rotor, and thus the rotating shaftis rotationally driven. One end portion of the rotating shaftis connected to the compression mechanismsuch hat the compression mechanismis drivable.

The compression mechanismis driven by the electric motorto compress a refrigerant. The compression mechanismand the electric motorare disposed in series inside the casing. The compression mechanismis not specifically limited, but is a scroll compression mechanism including a fixed scroll and a movable scroll. Note that the compression mechanismis not limited to a scroll type, and an appropriate type of compression mechanism such as a reciprocating type that reciprocates a piston connected to a swing plate can be adopted.

The inverterconverts, for example, a direct current from a battery (not shown) of the vehicle into an alternating current, and supplies the alternating current to the electric motor.

The casingconstitutes an outer shell of the electric compressor. The electric motor, the compression mechanism, and the inverterare housed inside the casing. The casingis provided with a suction portand a discharge portto which a refrigerant pipe (not shown) of the vehicle air conditioner is connected. The positions of the suction portand the discharge portwill be described later.

In the electric compressor, when the electric motoris driven by the inverter, the electric motordrives the compression mechanismvia the rotating shaft (output shaft)of the electric motor. Thus, the electric compressorsucks the refrigerant (low-pressure refrigerant) of the vehicle air conditioner from the suction port, compresses the refrigerant by the compression mechanism, and discharges the compressed refrigerant (high-pressure refrigerant) from the discharge port

The mounting portionis formed in the casingand mounts the casingto a predetermined object C (here, the vehicle body). The mounting portionis formed integrally with the casing. The structure, position, and the like of the mounting portionwill be described later.

The statorof the electric motoris incorporated (fitted) inside the casingby shrink fitting. During the shrink fitting, the casing(specifically, a motor casingto be described later) is heated. Therefore, when the mounting portionis heated together with the casingat the time of shrink fitting (assembling) of the stator, the mounting portionis deformed, and the position accuracy of the mounting portionmight decrease due to the assembly of a stator. On the other hand, the electric compressorhas a structure described below.

In the electric compressor, the casingincludes the motor casingin which the electric motoris housed, a compression mechanism casingin which the compression mechanismis housed, and an inverter casingin which the inverteris housed. That is, the casingis separated into at least the motor casing, the compression mechanism casing, and the inverter casing. The casing members (,,) are formed mainly by casting, for example. The casing members (,,) are integrally fastened by a fastening device such as bolts to constitute the casing.

In the present embodiment, the motor casingis provided between the compression mechanism casingand the inverter casing. The motor casinghas, for example, a cylindrical portionformed in a substantially cylindrical shape so as to surround the periphery of the electric motor. One end face of the cylindrical portionis in contact with the compression mechanism casing, and the other end face of the cylindrical portionis in contact with the inverter casing. The suction portis provided at an inverter-side end of the cylindrical portionof the motor casing. The statorof the electric motoris assembled inside the cylindrical portionof the motor casingby shrink fitting. During this shrink fitting, only the motor casingof the casingis heated.

In the present embodiment, the compression mechanism casinghas a cylindrical portionformed in a substantially cylindrical shape so as to surround the periphery of the compression mechanism. One opening of the cylindrical portionis closed. An opening side end face of the cylindrical portionof the compression mechanism casingabuts on an end face of the cylindrical portionof the motor casing. The outer diameter of the cylindrical portionof the compression mechanism casingis matched with the outer diameter of the cylindrical portionof the motor casing.

In the present embodiment, the inverter casingincludes, for example, an inverter case main body portionand an inverter cover portion. The inverter casingis formed in a substantially box shape that is long in a direction orthogonal to a central axis X of the rotating shaftof the electric motor. The inverter case main body portionhas a bottom wallfixed to the motor casingand a side wallextending from an edge of the bottom wall. The bottom wallis formed in a substantially rectangular shape in a plan view, and the side wallis formed in a substantially rectangular annular shape in a plan view as viewed toward the bottom wall. The inverter cover portionis formed in a substantially rectangular flat plate shape in a plan view. The inverter cover portionis fixed to the inverter case main body portionwith bolts or the like so as to close the opening of the inverter case main body portion. To the bottom wallof the inverter case main body portion, a substrate constituting the inverteris fixed.

In the present embodiment, the inverter casingprotrudes toward the object C from the outer surface of the compression mechanism casingand the outer surface of the motor casing. Specifically, in a state where the inverter casingis fixed to the motor casing, one end side portion in the longitudinal direction of the inverter casingprotrudes (projects) to the object C side from the outer surface of the compression mechanism casingand the outer surface of the motor casing.

Referring to, in the present embodiment, the object C is located above the casing, and the casingis suspended below the object C via the mounting portion. That is, the electric compressoris suspended below the object C via the mounting portion.

Next, the structure, position, shape, and the like of the mounting portionwill be described in detail.

The mounting portionincludes a first mounting legprovided in the compression mechanism casingand a second mounting legprovided in the inverter casing. That is, the mounting portionincludes a plurality of mounting legs, a part (first mounting leg) of the plurality of mounting legs is provided in the compression mechanism casing, and the rest (second mounting leg) of the plurality of mounting legs is provided in the inverter casing. Therefore, the plurality of mounting legs is provided in a casing part of the casingavoiding the motor casing.

Specifically, the first mounting legis provided at the top of the cylindrical portionof the compression mechanism casingon the object C side. The second mounting legis provided on the upper surface of the inverter casing, that is, the surface of the side wallof the inverter case main body portionon the object C side. The first mounting legand the second mounting legextends linearly toward the object C.

In the present embodiment, the number (figures) of the first mounting legsis one (one), and the number (figures) of the second mounting legsis two (two). Therefore, in the present embodiment, the electric compressoris suspended below the object C via three hanging tools (one first mounting legand two second mounting legs). Specifically, in a plan view of the casingviewed from above, one first mounting legis disposed at the top of the cylindrical portionso as to overlap the central axis X, and the two second mounting legsare provided to be separated from each other in the direction orthogonal to the central axis X on the upper surface of the side wallof the inverter casing. In a plan view of the casingviewed from above, the central axis line X is located between the two second mounting legs. The center of gravity of electric compressoris located in a region inside a virtual triangle formed by the one first mounting legand the two second mounting legsin a plan view of casingviewed from above.

In the present embodiment, a seat portion (,) having a seating face (,) in contact with the object C is formed at the distal ends of the first mounting legand the second mounting leg. The seat portion (,) is formed with a female screw (,). The seating faceof the seat portionof the first mounting legand the seating faceof the seat portionof the second mounting legare located on the same virtual plane P.

Specifically, the seat portions (,) are formed in a disk shape, and the seating faces (,) are, for example, a flat circular surface constituted of the end faces of the seat portions (,). The female screw (,) is formed downward from the seating face (,) to a predetermined depth, for example.

The female screw (,) is screwed with a screw portion of a bolt inserted through a through hole not shown formed in the object C. Thus, the seat portionof the first mounting legand the seat portionof the second mounting legare fastened to the object C. As a result, the casingis mounted on the lower surface of the object C so as to be suspended below the object C via the three mounting legs (,,).

In the present embodiment, a total length Lof the first mounting legis longer than a total length Lof the second mounting leg. Specifically, here, the first mounting legis formed longer than the second mounting legby a distance corresponding to a step in the vertical direction between the top of the cylindrical portionof the compression mechanism casingand the upper surface of the inverter casing.

In the present embodiment, the first mounting legincludes the seat portiondescribed above, a leg main bodyformed in a columnar shape (in this case, a cylindrical shape), and a reinforcing ribextending in the leg portion lateral direction along an outer surface (outer peripheral surface) of leg main body. Similarly, the second mounting legincludes the seat portiondescribed above, a leg main bodyformed in a columnar shape, and a reinforcing ribextending in the leg portion lateral direction along the outer peripheral surface of a leg main body.is a cross-sectional view of the first mounting leg, andis a cross-sectional view of the second mounting leg.are cross-sectional views of the seat portion (,) as viewed from the back surface side (the side opposite to the seating face (,)).

Specifically, referring to, the reinforcing ribof the first mounting legincludes a first ribextending in the leg portion lateral direction along the motor casing side portion (top portion) on the outer surface (outer peripheral surface) of the leg main body, and a second riband a third riborthogonal to the first rib. That is, the first mounting leghas a substantially T-shaped cross section with the first ribfacing the motor casing side. The first ribextends parallel to the central axis X at a position overlapping the central axis X in the cross-sectional view, and the second riband the third ribextend in a direction orthogonal to the central axis X. Referring to, in the present embodiment, each rib (,,) of the first mounting legis formed away from the outer surface of the leg main bodytoward the cylindrical portionof the compression mechanism casing. Specifically, the edge portions of the ribs (,,) are formed in an arc shape as a whole, and the ribs (,,) have an arc-shaped contour (arc fillet). In addition, in the present embodiment, the base end portion (root portion) of the first ribof the first mounting legis located closer to the leg main bodyside from the motor casing side end faceof the cylindrical portion.

Referring to, the reinforcing ribof each of the second mounting legsincludes a fourth ribextending in the leg portion lateral direction along the motor casing side portion (top portion) on the outer surface (outer peripheral surface) of the leg main body, and a fifth riband a sixth riborthogonal to the fourth rib. That is, the second mounting legshave a substantially T-shaped cross section with the fourth ribfacing the motor casing side. The fourth ribextends parallel to the central axis X, and the second riband the third ribextend in a direction orthogonal to the central axis X. Referring to, in the present embodiment, each rib (,,) of the second mounting legis formed away from the outer surface of the leg main bodytoward the cylindrical portionof the compression mechanism casing. Specifically, also in the second mounting leg, the edge of each rib (,,) is formed in an arc shape as a whole, and each rib (,,) has an arc-shaped contour (arc fillet).

As described above, in the electric compressoraccording to the present embodiment, the casingincludes the motor casing, the compression mechanism casing, and the inverter casing. The mounting portionformed in the casingthat mounts the casingto the object C includes the first mounting legprovided in the compression mechanism casingand the second mounting legprovided in the inverter casing. Therefore, the plurality of mounting legs (the first mounting portionand the second mounting portion) constituting the mounting portionis provided in the casing part of the casingavoiding the motor casing. That is, the mounting portionis provided in the compression mechanism casingand the inverter casing, which are casing parts separated from the motor casingheated at the time of shrink fitting of the stator. As a result, the mounting portionis not heated together with the motor casingat the time of shrink fitting of the stator, and the position accuracy of the mounting portionfalls within the range of the intended necessary accuracy. Therefore, deterioration in the position accuracy of the mounting portiondue to the assembly of a stator is stopped. As described above, the electric compressorhas a structure capable of stopping deterioration in position accuracy of the mounting portiondue to the assembly of a stator.

In addition, since the inverter casingis fixed to the object C via the second mounting leg, the inverter casingis stably supported. As a result, vibration of the circuit components of the inverteris suppressed.

In the present embodiment, the number of the first mounting legsis one, and the number of the second mounting legsis two. Thus, the mounting portioncan stably mount the casingto the object C with a simple structure by the three-point support structure using the three mounting legs (,,).

In the present embodiment, a seat portion (,) having a seating face (,) in contact with the object C is formed at the distal ends of the first mounting legand the second mounting leg. The seat portion (,) is formed with a female screw (,). Thus, the electric compressoris easily mounted on the object C via the mounting portiononly by screwing the screw portion of the bolt extending from the object C side to the female screw (,).

In the present embodiment, the seating faceof the seat portionof the first mounting legand the seating faceof the seat portionof the second mounting legare located on the same virtual plane P. Thus, the electric compressoris easily mounted on the object C when the mounting site (fastening site) of the object C to the electric compressoris located on the same virtual plane P.

In the present embodiment, the total length Lof the first mounting legis longer than the total length of the second mounting leg, and the first mounting legincludes the leg main bodyand the reinforcing ribextending in the leg portion lateral direction along the outer surface of leg main body. Thus, the strength of the first mounting legis enhanced by the reinforcing ribin the case where the inverter casingprotrudes to the object C side from the outer surface of the compression mechanism casingand the outer surface of the motor casing, and the first mounting leghas to be formed longer than the second mounting leg. As a result, the electric compressoris more firmly mounted on the object C, and durability against vibration is improved.

In the present embodiment, the motor casingis provided between the compression mechanism casingprovided with the first mounting legand the inverter casingprovided with the second mounting leg. That is, the mounting portionis provided to be distributed to one end portion and the other end portion in the longitudinal direction of the electric compressor. Thus, the electric compressoris supported (suspended) by both end supports, and a stable supporting structure of the electric compressoris constructed. In addition, the first mounting legincludes the leg main body, the first rib, the second rib, and the third rib, and has a T-shaped cross section as a whole. Thus, the strength of the first mounting leglonger than the second mounting legis more effectively enhanced, and durability against vibration is more effectively improved.

In the present embodiment, each rib (,,) of the first mounting legis formed so as to be away from the outer surface (outer peripheral surface) of the leg main bodyas approaching the cylindrical portionof the compression mechanism casing. Thus, stress concentration on the base portion of the first mounting legat the time of occurrence of vibration or the like is reduced, strength of the base portion of the first mounting legis improved, and durability against vibration is remarkably improved. The same applies to the second mounting leg. In the following, modifications of the electric compressorof the present embodiment will be described.

is an enlarged perspective view for explaining a modification of the first mounting leg. In the present embodiment, the base end portion of the first ribof the first mounting legis located at a position farther toward the leg main bodyside from the motor casing side end faceof the cylindrical portion, but the present invention is not limited to this, and may extend to the motor casing side end faceof the cylindrical portionas shown in.

Specifically, referring to, the first ribof the first mounting leghas a rib main bodyand a rib root. The rib main bodyis formed so as to be away from the outer surface (outer peripheral surface) of the leg main bodytoward the cylindrical portionof the compression mechanism casing. Specifically, the edge portion of the rib main bodyis formed in an arc shape, and the rib main bodyhas an arc-shaped contour (arc fillet). The rib rootis a portion constituting the base end portion of the first rib. The rib rootconnects the rib main bodyto the outer surface of the cylindrical portionof the compression mechanism casing, and extends from the outer surface (outer peripheral surface) of the leg main bodyto the position of the motor casing side end faceof the cylindrical portion. That is, the rib rootprotrudes radially outward from the outer peripheral surface of the cylindrical portion, and the rib main bodyextends upward continuously to the end of the rib root. Thus, the strength of the entire base end portion (root portion) of the first ribis reinforced by the rib rootformed to be wide and maximum, and the stress concentration in the rib root(base end portion of the first mounting leg) is more effectively reduced. Specifically, the stress (stress concentration) at the motor casing side end at the base end portion of the first ribis remarkably reduced.

In addition, although not shown, each rib (,,,,,) may linearly extend in the vertical direction. Furthermore, the number of the first mounting legsis not limited to one but may be two or more, and the number of the second mounting legsis not limited to two but may be one or three or more.

In some cases, the mounting site (fastening site) of the object C to the electric compressoris not located on the same virtual plane P. In this case, the total length Lof the first mounting legand the total length Lof the second mounting legare appropriately set according to the distance between the mounting site and the compression mechanism casingand the distance between the mounting site and the inverter casingin the object C. There may be the case where the total length Lof the first mounting legis substantially equal to the total length Lof the second mounting leg(seewhich is an enlarged perspective view for describing another modification), or the case where the total length Lof the first mounting legis shorter than the total length Lof the second mounting leg(not shown).

The description of the present embodiment is an example for describing the present invention, and does not limit the invention described in the claims. In addition, the configuration of the components of the present invention is not limited to the foregoing embodiment, and various modifications are feasible within the technical scope described in the claims.