JP2010048146A - Inverter integrated type motor-driven compressor - Google Patents

Abstract

An object of the present invention is to provide an electric compressor with a built-in inverter that can be operated with high efficiency by preventing a reduction in maximum cooling capacity even if suction pressure loss due to inverter cooling occurs.
A compression mechanism portion that sucks, compresses and discharges fluid, a main body casing that includes an electric motor that drives the compression mechanism portion, an inverter case that includes an inverter that drives the electric motor, and the inverter case are sealed. In the inverter-integrated electric compressor that includes an inverter cover that provides a refrigerant suction passage and cools the back surface of the inverter installation wall, the auxiliary suction passage communicated with the suction passage from the geometric compression start point of the compression mechanism section Is placed facing the compression chamber.
[Selection] Figure 1

Description

  The present invention relates to an electric compressor in which a compression mechanism portion that sucks, compresses and discharges fluid and an electric motor that drives the compression mechanism portion are built in a fuselage container, and the electric motor is driven by an inverter.

  In this type of electric compressor, an inverter, a compression mechanism unit, and an electric motor are partitioned from each other (see, for example, Patent Document 1). The one described in Patent Document 1 is provided with a partition wall that partitions an airframe container into a compression chamber and an inverter chamber in the axial direction, and a compression mechanism and an electric motor are accommodated in the compression chamber, and an inverter is accommodated in the inverter chamber. Yes. Here, the inverter is a typical structure in a so-called low-pressure compressor that faces the suction side where the motor is located through the partition wall, and cools the inverter and the motor with suction refrigerant and then flows into the compression mechanism. . In addition, the one described in Patent Document 2 is a machine body container containing an electric motor, a compression mechanism part, and an inverter case containing an inverter on the opposite side of the electric motor across the compression mechanism part and fastened with bolts or the like in the axial direction. It is.

The suction refrigerant flowing in from the suction hole provided in the compression mechanism is once guided to a passage provided in the inverter case, and after returning heat to the inverter, is returned to the compression mechanism. Further, the refrigerant gas compressed by the compression mechanism portion is discharged from a discharge hole provided in the fuselage container after cooling the electric motor. This is a typical structure in a so-called high-pressure compressor.
Japanese Unexamined Patent Publication No. 2000-291557 (FIG. 10) Japanese Patent Laying-Open No. 2004-183631 (FIG. 11)

  However, since the structure described in Patent Document 1 is sucked into the compression section after exchanging heat with the inverter and the high heat-generating parts of the electric motor by the sucked refrigerant, the volume efficiency is lowered due to the rise of the sucked refrigerant temperature, and the compressor Greatly impacts performance. Furthermore, since the refrigerant discharged from the compression mechanism is directly discharged to the outside without reaching the motor side, the lubricating oil supplied to the compression mechanism and accompanying the discharged refrigerant should be separated to improve the performance of the refrigeration cycle. Then, it is difficult to separate because it is only performed in the discharge process to the outside. For this reason, a full-scale and large-sized separator is required, which causes an increase in the size and weight of the fuselage container.

  On the other hand, the structure described in Patent Document 2 is different from the structure described in Patent Document 1 in that the suction refrigerant is used only for inverter cooling, and the lubricating oil separator is an empty body container in which the electric motor is accommodated. Since the space can be provided, there are great advantages in terms of performance and the size of the aircraft container.

  However, in the structure described in Patent Document 2, the suction refrigerant passage provided in the inverter case is narrowed to increase the flow rate in order to promote cooling of the inverter, or the heat radiation fin is provided to promote heat radiation. Since measures such as this are taken, pressure loss is likely to occur due to fluid resistance, and volume efficiency tends to decrease at the time of a large amount of circulation during high-speed rotation, which is problematic.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an inverter-integrated electric compressor structure capable of drastically reducing the cost and efficiently reduce the volume efficiency due to pressure loss during high-speed rotation while efficiently cooling the inverter. The object is to provide an electric compressor.

  In order to solve the above-described conventional problems, an electric compressor according to the present invention includes a compression mechanism that performs suction, compression, and discharge of fluid, a main body casing that includes an electric motor that drives the compression mechanism, and the electric motor. An inverter case containing a drive inverter and an inverter cover for sealing the inverter case are provided, the compression mechanism is accommodated in the main body casing, and is sandwiched between an inner peripheral end surface of the inverter case and an inner surface stepped portion of the main body casing. And a structure sealed with a sealing material between the end face of the main body casing and the outer peripheral end face of the inverter case, and the refrigerant between the inner peripheral end face of the inverter case and the end face of the compression mechanism portion. This is an inverter-integrated electric compressor that is provided with a suction passage to cool the back surface of the inverter installation wall.

  The suction portion of the compression mechanism portion is provided with a sub-suction passage that communicates with a suction passage that leads from the geometric compression start point to the compression chamber so as to face the compression chamber. Since the suction gas returns to the suction passage when the compression starts, the apparent volumetric efficiency decreases, but at the time of high-speed rotation, suction occurs at the geometrical suction end point (compression start point) due to the occurrence of pressure loss due to the inverter cooling. Although the pressure at the end is slightly reduced, the suction process continues through the secondary suction passage, so that the suction gas continues to flow, and the apparent volumetric efficiency can be increased as compared with the case where there is no secondary suction passage. Example 1 is a case of a scroll type compressor, and a sub-intake passage is provided in at least one of a fixed scroll or an orbiting scroll end plate.

  In the second embodiment, the auxiliary suction passage is provided on the inner side surface of the outer wall adjacent to the suction passage of the fixed scroll. The third embodiment is a case of a vane rotary type compressor, which is a case where an inner wall of a cylindrical cylinder constituting a compression chamber is installed. In the fourth embodiment, the side where the cylindrical cylinder is closed from both sides. Shown when installed on at least one of the plates.

  The inverter-integrated electric compressor of the present invention can be directly mounted on an engine such as a hybrid vehicle due to the reduction in size and weight, and can ensure a large amount of refrigerant circulation even if it is small and rotates at high speed.

  A first aspect of the present invention is a compression mechanism portion that performs suction, compression, and discharge of fluid, a main body casing that includes an electric motor that drives the compression mechanism portion, an inverter case that includes an inverter that drives the electric motor, and the inverter case In an inverter-integrated electric compressor that includes an inverter cover that seals and cools the back surface of the inverter installation wall by providing a refrigerant suction passage, auxiliary suction that communicates from the geometric compression start point of the compression mechanism to the suction passage A passage is installed facing the compression chamber.

  According to a second aspect of the present invention, in the compression mechanism of the first aspect, the scroll mechanism is used, and the auxiliary suction passage is provided in at least one of the end plate of the fixed scroll or the orbiting scroll. This is an inverter-integrated electric compressor.

  A third invention is characterized in that the compression mechanism is of a scroll type, and the auxiliary suction passage is provided on the inner side surface of the outer wall on the fixed scroll side.

  According to a fourth aspect of the invention, the compression mechanism is a vane rotary type, and the auxiliary suction passage is provided on a side surface of the outer wall of the cylindrical cylinder.

According to a fifth aspect of the present invention, the compression mechanism is a vane rotary type, and the auxiliary suction passage is provided on at least one side wall that closes the cylindrical cylinder.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
1 is a longitudinal sectional view of an inverter-integrated electric compressor according to Embodiment 1 of the present invention. FIG. 1 shows one example in the case of a horizontal type electric compressor installed sideways by a mounting leg 2 around a body portion of the electric compressor 1. The electric compressor 1 includes a main body casing 3. An electric motor 5 is housed inside, and the compression mechanism 4 that is inserted into or pressed into the main casing 3 is driven. The electric motor 5 is driven by a motor drive circuit unit 101 incorporated in the inverter case 102. Further, the main body casing 3 is provided with a liquid storage section 6 for storing a liquid used for lubricating each sliding section including the compression mechanism section 4. The refrigerant to be handled is a gas refrigerant, and a liquid such as a lubricating oil 7 is employed as a liquid to be used for lubrication of each sliding part and a seal of the sliding part of the compression mechanism part 4. The lubricating oil 7 is compatible with the refrigerant. However, the present invention is not limited to these. Basically, a compression mechanism unit 4 that sucks, compresses and discharges liquid, a main body casing 3 that houses an electric motor 5 that drives the compression mechanism unit 4, and a motor drive circuit unit 101 that drives the electric motor 5 are incorporated. The following description does not limit the description of the scope of the claims.

  The compression mechanism section 4 of the electric compressor 1 according to the present embodiment is of a scroll type as an example. As shown in FIG. 1, the fixed end plate 11a and the fixed scroll 11 whose blades rise from the revolving end plate 12a are swung. When the compression space 10 formed by meshing with the scroll 12 moves the orbiting scroll 12 in a circular orbit with respect to the fixed scroll 11 via the drive shaft 14 by the electric motor 5, the external volume is changed by changing the volume. The refrigerant 30 returning from the cycle is sucked, compressed and discharged to the external cycle through the suction port 8 provided in the inverter case 102 and the discharge port 9 provided in the main body casing 3.

  At the same time, the lubricating oil 7 stored in the liquid storage part 6 of the main body casing 3 is driven by driving the positive displacement pump 13 or the like by the drive shaft 14 or using the differential pressure in the main body casing 3. As the orbiting scroll 12 is driven to rotate through the oil supply passage 15 of the shaft 14, the oil is supplied to the liquid reservoir 21 and the liquid reservoir 22 on the back surface of the orbiting scroll 12, and in the example shown in the figure, the lubricating oil supplied to the liquid reservoir 21. 7 is supplied to the back side of the outer peripheral portion of the orbiting scroll 12 through the orbiting scroll 12 to a predetermined restriction base such as a throttle 23 to back up the orbiting scroll 12, and the lubricating oil 7 is orbited through the orbiting scroll 12. The blade 12 of the scroll 12 is supplied to a holding groove 25 that holds a tip seal 24 that is an example of a seal member between the tip and the fixed scroll 11, and is fixed and rotated. Achieving sealing and lubrication between the scrolls 11 and 12. Further, another part of the lubricating oil 7 supplied to the liquid reservoir 21 lubricates the bearings 42 and 43 through the eccentric bearing 43, the liquid reservoir 22, and the main bearing 42, and then flows out to the electric motor 5 side. It is collected into the liquid storage unit 6.

Further, a main bearing member 51 having a pump 13, a sub-bearing 41, an electric motor 5, and a main bearing 42 is arranged from one end wall 3 a side in the axial direction in the main body casing 3. The pump 13 is accommodated from the outer surface of the end wall portion 3a and is held between the lid body 52 and the pump body 53 which is inserted into the lid body 52. 54 is connected to the liquid storage section 6 through 54. The auxiliary bearing 41 is supported by the end wall 3a, and the side connected to the pump 13 of the drive shaft 14 is supported. The electric motor 5 is configured such that the stator 5a can be rotationally driven by a rotor 5b that is fixed by shrink-fitting the stator 5a to the main casing 3 or is fixed by an annular member 17 and is fixed around the middle of the drive shaft 14. Yes. The main bearing member 51 is fixed to the fixed spiral portion 11 with a bolt (not shown) or the like, fitted into the opening end of the main body casing 3, and clamped by the inverter case 102 so that the compression mechanism portion 4 side of the drive shaft 14 is held. The main bearing 42 is used for bearing. Further, the orbiting scroll 12 is sandwiched between the main bearing member 51 and the fixed scroll 11 to constitute a scroll compressor. Between the main bearing member 51 and the orbiting scroll 12, a rotation restraining portion 57 for preventing the rotation of the orbiting scroll 12 such as an Oldham ring 57 and causing the circular movement is provided, and the drive shaft 14 is interposed via the eccentric bearing 43. The orbiting scroll 12 is connected to the orbiting scroll 12 so that the orbiting scroll 12 can be orbited on a circular path.

  The compression mechanism section 4 is provided with a discharge hole 31 and a reed valve 31a, and is opened to a discharge chamber 62 composed of a fixed end plate 11a and a lid 65. The discharge chamber 62 is an electric motor 5 having a discharge hole 9 between the compression mechanism portion 4 and the end wall 3a through the fixed scroll 11 and the main bearing member 51 or a communication passage 63 formed between them and the main body casing 3. To the side.

  The motor drive circuit unit 101 is configured by accommodating a circuit board 103 and an electrolytic capacitor (not shown) on the opposite side of the suction chamber 61 and the discharge chamber 62 with an end wall 102 a in the inverter case 102. Is mounted with an IPM (intelligent power module) 105 including a switching element having a high heat generation degree. The motor drive circuit unit 101 is electrically connected to the electric motor 5 or the like via a compressor terminal 106 connected by a harness connector 107, and the motor drive circuit unit 101 monitors the motor 5 for necessary information such as temperature. 101 is driven. For this reason, the motor drive circuit unit 101 is provided with a harness connector (not shown) for electrical connection with the outside.

  As described above, the electric motor 5 is driven by the motor drive circuit unit 101 to move the compression mechanism unit 4 in a circular orbit via the drive shaft 14 and to drive the pump 13. At this time, the compression mechanism section 4 is supplied with the lubricating oil 7 of the liquid storage section 6 by the pump 13 and receives the lubricating and sealing action, and sucks the return refrigerant from the refrigeration cycle through the suction port 8 provided in the inverter case 102. , Compressed and discharged from the discharge port 31 to the discharge chamber 62. The refrigerant discharged into the discharge chamber 62 enters the electric motor 5 side through the communication passage 63, and in the long process until the electric motor 5 is cooled and discharged from the discharge port 9 of the main body casing 3, the refrigerant collides, centrifuges, throttles, etc. The sub-bearing 41 is also lubricated by the accompanying partial lubricating oil 7 while various types of gas-liquid separation is performed and the lubricating oil 7 is separated.

  In the electric compressor 1 having the above configuration, a cooling passage structure in the inverter case 102 will be described with reference to FIG. FIG. 2 is an exploded view of the cooling passage space constituted by the inverter case 102 and the fixed end plate 11a. The refrigerant sucked from the suction port 8 provided in the inverter case 102 is diffused into the suction passage space 70, cools the end wall 102a, and exchanges heat with a heating element such as the IPM 105 mounted on the back surface. After that, it flows into the suction space 10 through the passage hole 71 of the fixed end plate 11a.

  In addition, the compressor terminal 106 is fixed to the inverter case 102 by a tome 80 or the like. The lead wire 81 from the electric motor 5 is connected to the harness connector 107 through a communication passage 82 provided in the vicinity of the outer periphery of the fixed end plate 11a, and is inserted and fixed to the compressor terminal 106.

  Further, the cooling effect can be further enhanced by providing guide fins 75 for controlling the flow of the refrigerant on the end wall 102a of the inverter case 102 at positions facing the heating elements mounted on the back surface.

FIG. 3 is a partial schematic view of the suction and compression initial steps in the scroll compressor. 11
The passage hole 71 is installed in a part of the fixed scroll, and the refrigerant enters the passage hole 71 due to the pressure drop accompanying the increase in the volume of the suction space 10 due to the turning movement of the orbiting scroll 12 through the passage hole 71.

  At this time, the suction space 10 is in a state just before the end of the suction, but the volumetric efficiency is lowered when the geometric (theoretical) suction end point 10a is reached in a state where the refrigerant does not sufficiently flow into the suction space 10 during high-speed rotation. Will be. Therefore, since the refrigerant can continue to flow by newly providing the auxiliary suction passage 72 communicating with the passage hole 71 at the position facing the suction space 10 of the scroll bottom plate 11b of the fixed scroll 11, the volumetric efficiency can be maintained high.

  FIG. 4 is a cross-sectional view of FIG. 3, and FIG. 5 shows the characteristics of the embodiment of the present invention with respect to the change in the volume efficiency and the amount of refrigerant circulation with respect to the rotation speed.

  In the high-speed rotation range, higher volume efficiency can be obtained than in the past. On the contrary, at the time of low speed rotation, the refrigerant once sucked returns to the passage hole 71 side from the sub suction passage 72 by the start of compression, so that the volumetric efficiency tends to decrease. However, the object of the present invention is to maximize the refrigerant circulation amount at the maximum rotation speed. The low speed characteristic can be ignored.

  FIG. 6 shows a case where the auxiliary suction passage 72 is installed on the inner inner wall 11 c of the outer wall of the fixed scroll 11.

(Embodiment 2)
7 and 8 show a case where the compression mechanism is a vane rotary type. The compression unit is composed of a rotor 210 rotating at a point close to the cylindrical cylinder 200, a plurality of vanes 211 arranged radially in the rotor, and side plates 205 and 206 closing the cylinder 200 from both sides. . In FIG. 7, the auxiliary suction passage 72 is notched in the inner wall of the cylindrical cylinder 200. A notch 202 is formed long with respect to the theoretical suction end position 201 represented by a one-dot chain line, and the above-described effects can be obtained from the auxiliary suction passage 72.

  FIG. 8 is a transverse sectional view when the auxiliary suction passage 72 is formed in a side plate 205 that closes the cylindrical cylinder 200 from both sides, and FIG. 9 is a longitudinal sectional view thereof.

  In this case, the same effect can be obtained.

  This time, the vane rotary type shows a case of a perfect cylinder, but it goes without saying that the same effect can be obtained even in the case of an elliptical cylinder or when the number of vanes changes.

  As described above, since the inverter-integrated electric compressor according to the present invention can obtain a larger amount of refrigerant circulation than the conventional inverter-integrated electric compressor, it can be reduced in size, weight, and efficiency. This facilitates mounting on the engine and can be widely applied to environmental vehicles such as hybrid vehicles.

1 is a longitudinal sectional view of an inverter-integrated electric compressor according to Embodiment 1 of the present invention. 1 is an exploded structural view of the cooling passage space of the inverter case shown in FIG. Schematic diagram of suction / compression process of scroll compressor shown in FIG. Cross-sectional schematic diagram of FIG. Volumetric efficiency and refrigerant circulation characteristic chart Schematic diagram of suction / compression process of another embodiment of scroll compressor Schematic diagram of suction / compression process of inverter-integrated electric compressor in Embodiment 2 of the present invention Suction / compression process schematic diagram of another example of the inverter-integrated electric compressor according to Embodiment 2 of the present invention. Vertical cross-sectional schematic diagram of FIG. Sectional view of the conventional inverter-integrated electric compressor of Document 1 Sectional view of the conventional inverter-integrated electric compressor of Document 2

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electric compressor 2 Mounting leg 3 Main body casing 3a Seal groove 3b O-ring 3c Minute gap 4 Compression mechanism part 5 Electric motor 5a Stator 6 Liquid storage part 7 Lubricating oil 8 Suction port 9 Discharge port 10 Suction space 11 Fixed scroll 11a Fixed end plate DESCRIPTION OF SYMBOLS 12 Orbiting scroll 12a Orbiting end plate 13 Pump 14 Drive shaft 15 Oil supply path 17 Annular member 21 Liquid reservoir 22 Liquid reservoir 23 Restriction 24 Tip seal 25 Holding groove 30 Refrigerant 31 Discharge hole 41 Sub bearing 42 Main bearing 43 Eccentric bearing 51 Main bearing member 52 Lid 53 Pump chamber 54 Suction passage 57 Oldham ring 61 Suction chamber 62 Discharge chamber 63 Communication passage 65 Lid body 70 Suction passage space 71 Passage hole 72 Sub suction passage 75 Guide fin 80 Tomewa 81 Lead wire 82 Connection passage 101 Motor drive circuit Part 102 Inverter case 1 02a End wall 103 Circuit board 105 IPM
106 Compressor terminal 107 Harness connector 113 Inverter cover 200 Cylinder 205 Side plate 210 Rotor 211 Vane

Claims (5)

A compression mechanism section that sucks, compresses and discharges fluid; a main body casing that includes a motor that drives the compression mechanism section; an inverter case that includes an inverter that drives the motor; and an inverter cover that seals the inverter case In the inverter-integrated electric compressor provided with a refrigerant suction passage to cool the back surface of the inverter installation wall, a secondary suction passage communicating with the suction passage from the geometric compression start point of the compression mechanism section is formed in the compression chamber. Inverter-integrated electric compressor characterized by being installed facing. 2. The inverter-integrated electric compressor according to claim 1, wherein the compression mechanism is of a scroll type, and the auxiliary suction passage is provided in at least one of a fixed scroll or an end plate of the orbiting scroll. 2. The inverter-integrated electric compressor according to claim 1, wherein the compression mechanism is of a scroll type, and the auxiliary suction passage is provided on a side surface of the outer wall of the fixed scroll side. 2. The inverter-integrated electric compressor according to claim 1, wherein the compression mechanism is a vane rotary type, and the auxiliary suction passage is provided on a side surface of an outer wall of the cylindrical cylinder. 2. The inverter-integrated electric compressor according to claim 1, wherein the compression mechanism is of a vane rotary type, and the auxiliary suction passage is provided on at least one of both side walls closing the cylindrical cylinder.