Electric compressor

Abstract

Electric compressor (100), comprising: a compression mechanism (161) that compresses refrigerant; an electric motor (131) that drives the compression mechanism (161); a driver circuit (121) that drives the electric motor (131); a housing (111) that defines a motor chamber (151) in which the electric motor (131) is housed; a cover (126) attached to the housing (111), the cover (126) being configured to interact with the housing (111) to form a driver circuit chamber (152) in which the driver circuit (121) is received; a rotating shaft (156) by which a rotation of the electric motor (131) is transmitted to the compression mechanism (161);and a relay connection section (521, 621) which establishes an electrical connection between a wire (541, 641) of the driver circuit (121) and a wire (531, 631) of the electric motor (131), characterized in that the housing (111) has a partition (113) which separates the motor chamber (151) and the driver circuit chamber (152) from each other, and the relay connection section (521, 621) is arranged between the partition (113) and the rotating shaft (156), wherein the relay connection section (521, 621) is arranged along a rotation axis (101) of the rotating shaft (156) between a bearing (142) which rotatably supports the rotating shaft (156) and the partition (113).

Description

BACKGROUND OF THE INVENTIONThe present invention relates to an electric compressor, and more particularly to an electric compressor in which an inverter is integrated.Japanese Unexamined Patent Application Publication No. 2012-184 752 A discloses an electric compressor manufactured to prevent a short circuit between terminal pins as a hermetic terminal and a terminal holder or a housing.The electric compressor disclosed in the above publication includes a housing, a compression mechanism, and an electric motor accommodated in the housing. The compressor further includes an inverter housing fixed to a part of the outer circumferential surface of the housing to thereby form an inverter accommodating chamber in which an inverter is provided. A hermetic terminal is electrically connected to the inverter via a connector of the inverter. Further, in the housing, the hermetic terminal is electrically connected to a lead wire drawn out from a coil of the stator of the electric motor via a cluster block.Various types of electric compressors are disclosed in Japanese Unexamined Patent Application No. JP 2006-42 409 A, JP 2009-264 172 A, JP 2010-59 809 A, JP 2002-98 054 A, JP 2003-97 435 A, JP H03-281 993 A and JP 2012-215 090 A, and also in JP S63-28 246 A and laid-open patent application JP 2 657 759 B2. Patent application EP 2 375 072 A1 discloses an electric compressor in which a relay terminal portion is disposed between a partition wall separating a motor chamber from a drive circuit chamber and a rotary shaft of the compressor in a radial direction of the rotary shaft.As disclosed in Japanese Unexamined Patent Application Publication No. 2012-184 752, an electric compressor with an integrated inverter is known. In the electric compressor disclosed in Application Publication No. 2012-184 752 A, a cluster block is used as a relay terminal portion for providing an electrical connection between the inverter and the electric motor. However, the size of the housing accommodating a compression mechanism and an electric motor, or the size of the electric compressor itself may be increased depending on the installation location of the relay terminal portion.The present invention, which has been made in view of the above circumstances, is directed to provide an electric compressor having a smaller size.SUMMARY OF THE INVENTIONAccording to an aspect of the present invention, there is provided an electric compressor including a compression mechanism that compresses refrigerant, an electric motor that drives the compression mechanism, and a drive circuit that drives the electric motor. The electric compressor further includes a housing forming therein a motor chamber in which the electric motor is accommodated, and a cover fixed to the housing, a rotation shaft, and a relay terminal portion. The cover is configured to cooperate with the housing to form a driver circuit chamber in which the driver circuit is housed. The rotation of the electric motor is transmitted to the compression mechanism via the rotation shaft. The relay terminal portion provides an electrical connection between a wire of the drive circuit and a wire of the electric motor. The housing has a partition wall separating the motor chamber and the drive circuit chamber. The relay terminal portion is disposed between the partition wall and the rotating shaft, and the relay terminal portion is disposed along a rotation axis of the rotating shaft between a bearing that rotatably supports the rotating shaft and the partition wallOther aspects and advantages of the invention will become apparent from the following description taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the invention.BRIEF DESCRIPTION OF THE DRAWINGSFIG. 1 is a partially cross-sectional view showing the entire structure of an electric compressor according to an embodiment of the present invention; FIG. 2 is an enlarged cross-sectional view showing a part of the compressor of FIG. 1 enclosed by the two-dot chain line II; FIG. 3 is a cross-sectional view of a first modification of a structure in which the movement of a cluster block is restricted according to the embodiment of the present invention; FIG. 4 is a side cross-sectional view of the first modification of the structure in which the movement of the cluster block of FIG. 3 is restricted according to the embodiment of the present invention; and FIG. 5 is a cross-sectional view of a second modification of the structure in which the movement of a cluster block is restricted according to the embodiment of the present invention.DETAILED DESCRIPTION OF THE EMBODIMENTSAn embodiment of the present invention will now be described with reference to the accompanying drawings. Note that each reference sign is used to denote the same or similar components or parts throughout the specification and the drawings.FIG. 1 is a partial cross-sectional view showing the entire structure of an electric compressor 100 according to the present embodiment of the present invention. FIG. 2 is an enlarged cross-sectional view showing a part of the electric compressor 100 of FIG. 1 enclosed by the two-dot chain line II. The electric compressor 100 is of a type mounted on a vehicle and used for an air conditioner of the vehicle.The electric compressor 100 may be mounted on, for example, a hybrid vehicle that is driven by an internal combustion engine such as a gasoline engine and a diesel engine and supplied with electric power from a battery. Alternatively, the electric compressor 100 may be mounted on an electric vehicle or a fuel cell vehicle.The electric compressor 100 is connected to an engine and is mounted in an engine room of the vehicle. Alternatively, the electric compressor 100 may be mounted to a strut or any other suitable part provided in the engine compartment.The electric compressor 100 includes a compression mechanism 161, a rotation shaft 156, a bearing 141, a bearing 142, an electric motor 131, a housing 111, an inverter 121, an inverter cover 126, a cluster block 521, a wire 531 for the electric motor 131, a wire 541 for the inverter 121, a hermetic terminal 561, and a shaft support portion 211.The housing 111 is generally cylindrical in shape (particularly, circular cylindrical in shape). An inlet port 212 is formed in the housing 111 to receive refrigerant gas from an external refrigeration cycle (not shown) constituting an air conditioning system of the vehicle. The housing 111 has a suction housing part 216 having a bottomed cylindrical shape with an opening at one end thereof. The housing 111 further includes a discharge housing part 217 having therein an outlet port (not shown) connected to the external cooling circuit and through which refrigerant gas is discharged. The discharge housing portion 217 is coupled to the open end of the suction housing portion 216.The suction housing part 216 includes a partition wall 113 and a peripheral wall 112 axially extending from the outer periphery of the partition wall 113. The inlet port 212 is located at a position in the peripheral wall 112 of the suction housing part 216 adjacent to the partition wall 113.The partition wall 113 of the suction housing part 216 has a protrusion 116 which extends axially toward the electric motor 131. Specifically, the protrusion 116 extends in the direction in which the peripheral wall 112 extends from the partition wall 113.The protrusion 116 according to the present embodiment has a cylindrical shape with a recess portion 117.The compression mechanism 161 is disposed at a position in the suction housing part 216 that is closer to the outlet housing part 217 than to the inlet port 212. The compression mechanism 161 includes therein a compression chamber into which the refrigerant gas that has been taken into the suction housing part 216 through the inlet port 212 is introduced. Upon rotation of the rotary shaft 156, the compression mechanism 161 is operated to perform compression. The specific types of the compression mechanism 161 include, but are not limited to, a scroll type, a piston type, and a vane type.The rotating shaft 156 extends along a rotational axis 101 about which the electric motor 131 rotates. The rotating shaft 156 is disposed radially inward of the protrusion 116 in the suction housing part 216. The rotary shaft 156 is rotatably supported in the suction housing part 216 by the protrusion 116 through the bearing 142 mounted in the protrusion 116 and the shaft support portion 211 through the bearing 141 mounted in the shaft support portion 211, respectively. The rotating shaft 156 and the electric motor 131 are coaxial with each other and rotatable about the rotating axis 101. The rotary shaft 156 is connected at a first end thereof (or the end adjacent to the output housing part 217) to the compression mechanism 161, and is connected at a second end thereof (or the end adjacent to the partition wall 113) to a rotor 135 of the electric motor 131, which will be described later. The rotation of the electric motor 131 is transmitted to the compression mechanism 161 via the rotation shaft 156.The electric motor 131 is operated to rotate the rotary shaft 156, thereby driving the compression mechanism 161. The electric motor 131 includes the aforementioned rotor 135 and a stator 134. The rotor 135 and the stator 134 are radially spaced apart from each other.According to the present embodiment, the rotor 135 is fixed on the rotation shaft 156. The stator 134 includes a stator core 132 and a coil 133. The stator core 132 is fixed to the inner circumferential surface of the suction housing part 216. The coil 133 is wound around the teeth (not shown) of the stator core 132 to form coil ends 133 pprotruding from the both end surfaces of the stator core 132 in the axial direction of the rotation shaft 156.The suction housing part 216 defines a motor chamber 151 for receiving the electric motor 131.The bearing 141 and the bearing 142 are axially spaced apart from each other. The rotation shaft 156 is in contact with the bearing 141 at its first end and is in contact with the bearing 142 at its second end. In other words, the bearings 141 and 142 are arranged such that the rotor 135 is interposed therebetween in the axial direction of the rotation shaft 156.The bearing 141 is disposed between the rotation shaft 156 and the shaft support portion 211. The bearing 142 is disposed between the rotation shaft 156 and the protrusion 116. In other words, the bearing 142 is disposed in the protrusion 116.Although the bearings 141 and 142 according to the present embodiment are ball bearings, the type of the bearings 141 and 142 is not limited thereto.The inverter cover 126 according to the present embodiment has a generally cylindrical shape (specifically, a circular cylindrical shape). The partition wall 113 has a surface 113m facing the electric motor 131 on one side and a surface 113n on the other side. The inverter cover 126 is connected at its open end to the surface 113n of the case 111. The housing 111 and the inverter cover 126 cooperate to form the general contour of the electric compressor 100. Inverter cover 126 and housing 111 cooperate to define a driver circuit chamber 152 for receiving inverter 121.Specifically, the partition wall 113 of the suction housing part 216 separates the motor chamber 151 and the drive circuit chamber 152 from each other.The inverter 121 corresponding to the driving circuit of the present invention is operable to convert externally input DC power into AC power and apply the AC power to the electric motor 131. The inverter 121 includes a circuit board on which an inverter circuit is formed, and electronic components such as a capacitor and various wires.The compression mechanism 161, the electric motor 131, and the inverter 121 are arranged in the axial direction of the rotation shaft 156. Specifically, the electric motor 131 is located between the compression mechanism 161 and the inverter 121 in the axial direction of the rotation shaft 156.The cluster block 521 corresponding to the relay terminal portion of the present invention provides electrical connection between the wire 541 of the inverter 121 and the wire 531 of the electric motor 131.The cluster block 521 includes an insulating body portion 522 having a generally disk-shaped shape and a conductive connection terminal 523 embedded in the body portion 522.The body portion 522 of the cluster block 521 has a first insertion hole through which a part of the wire of the electric motor 131 or a conductive member electrically connected to the wire of the electric motor 131 is inserted. The body portion 522 further includes a second insertion hole through which a part of the wire of the inverter 121 or a conductive member electrically connected to the wire of the inverter 121 is inserted.According to the present embodiment, the cluster block 521 has a first insertion hole 571 through which the wire 531 of the electric motor 131 is inserted. The cluster block 521 further includes a second insertion hole 572 through which the hermetic terminal 561 connected to the wire of the inverter 121 is inserted.The wire 531 of the electric motor 131 is inserted into the first insertion hole 571 of the cluster block 521 and connected to a first end 523 pof the connection terminal 523. Subsequently, the wire 531 that communicates with the connection terminal 523 is fitted into the recess portion 117 of the protrusion 116.An end 541 pof the wire 541 extending from the inverter 121 is connected to a first end 561 pof the hermetic terminal 561 as a conductive member. The hermetic terminal 561 has a second end 561 qconnected to a second end 523 qof the connection terminal 523. Specifically, the wire 531 of the electric motor 131 and the wire 541 of the inverter 121 are electrically connected to each other through the hermetic terminal 561 and the connection terminal 523.The arrangement of the cluster block 521 will now be described in detail.The cluster block 521 is disposed between the partition wall 113 of the suction housing part 216 and the rotation shaft 156. According to the present embodiment, the cluster block 521 is disposed at a position where at least a part of the cluster block 521 overlaps with the bearing 142. Specifically, the bearing block 521 is disposed in a receiving space 153 defined by the partition wall 113 of the suction housing part 216, the rotation shaft 156, the bearing 142, and the protrusion 116. In addition, the cluster block 521 is disposed relative to the coil end 133 pin such an axial position that at least a part of the cluster block 521 overlaps with the coil end 133 pin the axial position when viewed in the radial direction of the rotating shaft 156.In the case of a configuration in which the cluster block 521 is disposed at a position radially outward of the stator 134, the size of the housing in the radial direction may be increased. In contrast, according to the configuration of the present embodiment in which the cluster block 521 is disposed radially inward of the stator 134 and between the partition wall 113 and the rotation shaft 156, an increase in the size of the housing in the radial direction can be prevented.Further, in a configuration in which the cluster block 521 is disposed entirely axially outside the stator 134, or is disposed at a location where the cluster block 521 does not overlap with the stator 134 in the axial direction of the rotation shaft 156, the size of the housing in the axial direction is increased. In contrast, according to the present embodiment in which the cluster block 521 is disposed at an axial position where at least a part of the cluster block 521 overlaps with the coil end 133 pwhen viewed in the radial direction of the rotation shaft 156, an increase in the size of the housing in the axial direction can be prevented.Hereinafter, the cluster block 521 and the bearing 142 according to the present embodiment will be described in more detail.The cluster block 521 has a protrusion 511. The protrusion 511 extends in the axial direction of the rotation shaft 156 from the outer periphery of the end surface of the cluster block 521 facing the bearing 142.The bearing 142 according to the present embodiment is a ball bearing. The bearing 142 includes an inner race 146, balls 148 as rolling elements, and an outer race 147. The inner race 146 is in contact with the rotary shaft 156. The balls 148 are disposed between the inner race 146 and the outer race 147.The cluster block 521 is in contact with the outer race 147 of the bearing 142 at its protrusion 511. The cluster block 521 is also in contact with the partition wall 113 on the side opposite to the protrusion 511. Thus, the cluster block 521 is disposed between the bearing 142 and the partition wall 113.With the protrusion 511, the cluster block 521 is disposed so as not to contact the inner race 146 of the bearing 142 rotating with the rotation shaft 156.In the above configuration, the cluster block 521 is prevented from moving in the axial direction of the rotating shaft 156 by the bearing 142 and the partition wall 113. The cluster block 521 can be prevented from being displaced in the housing with a simple structure that does not use a special positioning member such as a claw for the cluster block 521. Therefore, the configuration of the cluster block 521 is simplified, which contributes to reducing the manufacturing cost.Note that another component may be disposed between the cluster block 521 and the bearing 142. The cluster block 521 may be provided such that the cluster block 521 is free from contact with the partition wall 113 and / or the bearing 142 before the electric compressor 100 starts its operation. Even in such a configuration, as long as the connection terminal 523 in the cluster block 521 and the hermetic terminal 561 are fixedly connected to each other, the cluster block 521 is prevented from moving in the housing.In the case of the above-described configuration in which the cluster block 521 is provided free from contact with the partition wall 113 and / or the bearing 142, the cluster block 521 may be movable in the housing before the connection terminal 523 and the hermetic terminal 561 are fixedly connected to each other. In order to prevent such movement of the cluster block 521, it may be configured to prevent the cluster block 521 from moving by using a conductive member electrically connected to the wire of the inverter 121 or a wire of the electric motor 131, or a conductive member electrically connected to the wire of the electric motor 131, which will be described later in detail.Alternatively, contact between cluster block 521 and bulkhead 113 and / or bearing 142 may be prevented by press-fitting cluster block 521 into protrusion 116 or in any other suitable manner.First and second modifications of the structure of the present invention in which movement of the cluster block 521 is prevented by using the wire of the electric motor 131 will now be described with reference to FIGS. 3 to 5.FIG. 3 is a cross-sectional view taken along line III-III of FIG. 1, showing a first modification of the structure that inhibits the movement of the cluster block. FIG. 4 is a side cross-sectional view showing the first modification.As shown in FIGS. 3 and 4, the protrusion 116 according to the first modification is cylindrical and has three recess portions 118 spaced at regular angular intervals along the circumference of the rotating shaft 156.Further, a body portion 622 of a cluster block 621 of the first modification has three first insertion holes 671 formed at regular angular intervals along the circumference of the rotation shaft 156.A wire 631 of the electric motor 131 includes a lead wire 631U, a lead wire 631V, and a lead wire 631W respectively corresponding to the U phase, the V phase, and the W phase of the electric motor 131.A connection terminal 623 includes a connection terminal 623U, a connection terminal 623V, and a connection terminal 623W respectively corresponding to the U-phase, the V-phase, and the W-phase of the electric motor 131.The lead wires 631U, 631V, and 631W are inserted into their corresponding corresponding insertion holes 671 and connected to their respective corresponding ends 623 pof the connection terminal 623. The lead wires 631U, 631V, and 631W are connected to the connection terminals 623U, 623V, and 623W, and then inserted into the respective recess portions 118.A hermetic terminal 661 includes a hermetic terminal 661U, a hermetic terminal 661V, and a hermetic terminal 661W corresponding to the U-phase, the V-phase, and the W-phase of the electric motor 131, respectively.A wire 641 of the inverter 121 includes a lead wire 641U, a lead wire 641V, and a lead wire 641W respectively corresponding to the U phase, the V phase, and the W phase of the electric motor 131. The lead wire 641U and a first end 661 pof the hermetic terminal 661U are electrically connected to each other; the lead wire 641V and a first end 661 pof the hermetic terminal 661V are electrically connected to each other; and the lead wire 641W and the first end 661 pof the hermetic terminal 661W are electrically connected to each other.A second end 661 qof the hermetic terminal 661U is inserted into a second insertion hole 672 of the cluster block 621 and connected to a second end 623 qof the connection terminal 623U; a second end 661 qof the hermetic terminal 661V is inserted into a second insertion hole 672 of the cluster block 621 and connected to a second end 623 qof the connection terminal 623V; and a second end 661 qof the hermetic terminal 661W is inserted into a second insertion hole 672 of the cluster block 621 and connected to a second end 623 qof the connection terminal 623W.According to the above configuration, the lead wire 631U, the lead wire 631V, and the lead wire 631W are arranged at angularly spaced intervals in the circumferential direction. Specifically, the lead wires 631U, 631V, and 631W are arranged at regular angular intervals along the circumference of the rotation axis 101. With this arrangement, the lead wires 631U, 631V, and 631W serve to prevent the cluster block 621 from moving in the radial direction of the rotation shaft 156.In assembling the electric compressor 100, the cluster block 621 is first attached to the electric motor 131, and then the electric motor 131 with the cluster block 621 attached is mounted to the housing 111. According to the present embodiment in which the lead wires 631U, 631V, and 631W prevent the cluster block 621 from moving radially, there is no need to provide an additional mechanism for preventing (moving) the cluster block 621, so that the electric compressor 100 is simplified and the efficiency of assembling the electric compressor 100 is improved.FIG. 5 is a cross-sectional view of a second modification of the structure that inhibits the movement of the cluster block. According to the present embodiment, the lead wire 631U, the lead wire 631V, and the lead wire 631W are arranged at irregular angular intervals in the circumferential direction of the protrusion 116, as shown in FIG. 5.The interval between the lead wires 631U, 631V, and 631W may be optional as long as the arrangement of the lead wires 631U, 631V, and 631W prevents the cluster block 621 from moving in the radial direction of the protrusion 116.Although in the embodiment described with reference to FIGS. 1 and 2, the bearing 141 is provided adjacent to the compression mechanism 161 and the bearing 142 is provided adjacent to the inverter 121, the bearing 142 may be omitted as long as the rotation shaft 156 is suitably supported by the bearing 141 alone.In the present embodiment, a description has been made regarding the electric compressor 100 of an inline type in which the compression mechanism 161, the electric motor 131, and the inverter 121 are linearly arranged. However, the electric compressor 100 of the present invention may be of a camel type in which the inverter 121 is mounted on the peripheral wall 112 of the housing 111.It should be noted that the embodiments disclosed herein are examples in all respects and should not be construed as limiting. The scope of the present invention is determined not by the above-described descriptions but by the scope of the claims, and various modifications may be made within the scope and equivalence of the appended claims.The present invention is particularly applicable to an electric compressor in which an inverter is integrated.

Claims

An electric compressor (100) comprising: a compression mechanism (161) that compresses refrigerant; an electric motor (131) that drives the compression mechanism (161); a drive circuit (121) that drives the electric motor (131); a housing (111) that defines therein a motor chamber (151) in which the electric motor (131) is accommodated; a cover (126) attached to the housing (111), the cover (126) being configured to cooperate with the housing (111) to form a drive circuit chamber (152) in which the drive circuit (121) is accommodated; a rotation shaft (156) through which rotation of the electric motor (131) is transmitted to the compression mechanism (161); and a relay terminal portion (521, 621) that makes electrical connection between a wire (541, 641) of the drive circuit (121) and a wire (531, 631) of the electric motor (131), characterized in that the housing (111) has a partition wall (113) that separates the motor chamber (151) and the drive circuit chamber (152) from each other, and the relay terminal portion (521, 621) is disposed between the partition wall (113) and the rotation shaft (156), wherein the relay terminal portion (521, 621) is disposed along a rotation axis (101) of the rotation shaft (156) between a bearing (142) that rotatably supports the rotation shaft (156) and the partition wall (113).The electric compressor (100) according to claim 1, characterized in that the electric compressor (100) further includes another bearing (141) that rotatably supports the rotation shaft (156), the housing (111) includes a protrusion (116) extending from the partition wall (113) toward the electric motor (131), the bearing (142) is disposed between the protrusion (116) and the rotation shaft (156), and the relay terminal portion (521, 621) is disposed between the partition wall (113) and the bearing (142).The electric compressor (100) according to claim 2, characterized in that the relay terminal portion (521, 621) is provided such that the relay terminal portion (521, 621) is free from contact with the bearing (142).The electric compressor (100) according to claim 2, characterized in that the bearing (142) includes an inner race (146) in contact with the rotary shaft (156), an outer race (147) in contact with the protrusion (116), and rolling elements (148) disposed between the inner race (146) and the outer race (147), and the relay terminal portion (521, 621) is in contact with the outer race (147) and the partition wall (113).The electric compressor (100) according to any one of claims 1 to 4, characterized in that the wire (631) of the electric motor (131) includes a first lead wire (631U), a second lead wire (631V), and a third lead wire (631W), and the first lead wire (631U), the second lead wire (631V), and the third lead wire (631W) are arranged to prevent the relay terminal portion (521, 621) from moving in a radial direction of the rotating shaft (156).The electric compressor (100) according to any one of claims 1 to 5, characterized in that the electric motor (131) includes a stator core (132) and a coil (133) wound around the stator core (132) to form a coil end (133p) protruding from an end surface of the stator core (132) in an axial direction of the rotating shaft (156), and the relay terminal portion (521, 621) is disposed at an axial position in which at least a part of the relay terminal portion (521, 621) overlaps with the coil end (133p), as viewed in a radial direction of the rotating shaft (156).

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