Electric compressor

Abstract

This electric compressor comprises: a housing that includes a stator having a cylindrical shape; a rotating shaft that is disposed inside the housing and that has a rotor facing the stator; a low pressure wheel that is fixed to one axial side of the rotating shaft; a high pressure wheel that is fixed to the other axial side of the rotating shaft; a low pressure side air bearing that rotatably supports, in the housing, a low pressure side shaft section of the rotating shaft; a high pressure side air bearing that rotatably supports, in the housing, a high pressure side shaft section of the rotating shaft; a first air flow path that supplies compressed air from the housing to either one of the low pressure side air bearing and the high pressure side air bearing; a second air flow path that branches from the first air flow path and that supplies the compressed air to the other of the low pressure side air bearing and the high pressure side air bearing; and an air flow rate adjustment device that adjusts a flow rate of the compressed air flowing in the first air flow path and the second air flow path.

Description

[Technical Field]

[0001] The present disclosure relates to a two-stage compression type electric compressor. [Background technology]

[0002] For example, fuel cells require high-pressure air, and therefore a two-stage compression electric compressor is used. A two-stage compression electric compressor is configured such that a rotating shaft is rotatably supported in a housing, a low-pressure wheel is provided on one axial end of the rotating shaft, and a high-pressure wheel is provided on the other axial end. The rotating shaft is rotatably supported in the housing by air bearings. The air bearings include a low-pressure side air bearing arranged on the low-pressure wheel side and a high-pressure side air bearing arranged on the high-pressure wheel side. A portion of the compressed air compressed by the low-pressure wheel or the high-pressure wheel is bled and supplied to the low-pressure side air bearing and the high-pressure side air bearing. An example of an electric compressor equipped with such air bearings is described in Patent Document 1 below. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6579649 Summary of the Invention [Problem to be solved by the invention]

[0004] In a conventional electric compressor, a portion of the low-pressure compressed air is supplied to the low-pressure side air bearing, and a portion of the high-pressure compressed air is supplied to the high-pressure side air bearing. On the high-pressure wheel side Each of the annular passages has a circumferentially extending annular passage. A portion of the compressed air is stored in the annular passage, and the stored compressed air is supplied to the air bearing. In this configuration, the annular passage is a space having a predetermined volume, so pressure loss increases when compressed air is stored in the annular passage. This may cause the air bearing to which the compressed air is supplied to not function properly.

[0005] The present disclosure is devised to solve the above-mentioned problems, and aims to provide an electric compressor that can allow an air bearing to function properly by reducing pressure loss of compressed air. [Means for solving the problem]

[0006] In order to achieve the above-mentioned object, the electric compressor of the present disclosure comprises a housing having a cylindrical stator, a rotating shaft having a rotor arranged inside the housing and facing the stator, a low-pressure wheel fixed to one axial end of the rotating shaft, a high-pressure wheel fixed to the other axial end of the rotating shaft, a low-pressure side air bearing that rotatably supports the low-pressure side shaft portion of the rotating shaft in the housing, a high-pressure side air bearing that rotatably supports the high-pressure side shaft portion of the rotating shaft in the housing, a first air flow path that supplies compressed air from the housing to either the low-pressure side air bearing or the high-pressure side air bearing, a second air flow path that branches from the first air flow path and supplies compressed air to the other of the low-pressure side air bearing or the high-pressure side air bearing, and an air flow control device that adjusts the flow rate of compressed air flowing through the first air flow path and the second air flow path. [Effects of the Invention]

[0007] According to the electric compressor of the present disclosure, the pressure loss of the compressed air can be reduced, allowing the air bearing to function properly. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a vertical cross-sectional view showing the internal configuration of an electric compressor according to a first embodiment. [Figure 2] FIG. 2 is a cross-sectional view taken along line II-II of FIG. 1, illustrating the first air flow path. [Figure 3] FIG. 3 is a cross-sectional view taken along line III-III of FIG. 1, illustrating the first air flow path. [Figure 4] FIG. 4 is a cross-sectional view taken along line IV-IV of FIG. 1, illustrating the second air flow path. [Figure 5] FIG. 5 is a cross-sectional view taken along line VV of FIG. 1, illustrating the second air flow path. [Figure 6] FIG. 6 is a vertical cross-sectional view showing the internal configuration of the electric compressor of the second embodiment. [Figure 7] FIG. 7 is a vertical cross-sectional view showing the internal configuration of the electric compressor of the third embodiment. [Figure 8] FIG. 8 is a vertical cross-sectional view showing the internal configuration of the electric compressor according to the fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] Preferred embodiments of the present disclosure will be described in detail below with reference to the drawings. Note that the present disclosure is not limited to these embodiments, and when there are multiple embodiments, the present disclosure also includes configurations that combine the embodiments. Furthermore, the components in the embodiments include those that can be easily imagined by a person skilled in the art, those that are substantially identical, and those that are within the so-called equivalent range.

[0010] [First embodiment] <Configuration of electric compressor> FIG. 1 is a vertical cross-sectional view showing the internal configuration of an electric compressor according to a first embodiment.

[0011] As shown in FIG. 1, the electric compressor 10 includes a housing 11, a rotating shaft 12, a low-pressure wheel 13, a high-pressure wheel 14, a low-pressure side air bearing 15, a high-pressure side air bearing 16, a first air flow path 17, a second air flow path 18, and an air flow control device 19.

[0012] The housing 11 has a motor housing 21, a low-pressure side bearing housing 22, and a high-pressure side bearing housing 23. The motor housing 21 is cylindrical and has an expanded diameter at one axial end (the right side in FIG. 1). The low-pressure side bearing housing 22 is disk-shaped and is located on one axial end of the motor housing 21. The low-pressure side bearing housing 22 is detachably fastened to the one axial end of the motor housing 21 with a plurality of bolts. The high-pressure side bearing housing 23 is disk-shaped and is located on the other axial end of the motor housing 21. The high-pressure side bearing housing 23 is detachably fastened to the other axial end of the motor housing 21 with a plurality of bolts.

[0013] One axial opening of cylindrical motor housing 21 is closed by low-pressure side bearing housing 22, and the other axial opening is closed by high-pressure side bearing housing 23. Therefore, housing 11 has a hollow shape when low-pressure side bearing housing 22 and high-pressure side bearing housing 23 are fastened to motor housing 21.

[0014] A stator 31 is fixed to the inner periphery of the motor housing 21. The stator 31 is cylindrical. The stator 31 has a stator core 32 and a stator coil 33. The stator core 32 is cylindrical and fixed so that its outer periphery is in close contact with the inner periphery of the motor housing 21. The stator coil 33 is wound around the stator core 32 and partially housed inside the stator core 32, with low-voltage side coil end 33a and high-voltage side coil end 33b exposed to one side and the other side of the stator core 32 in the axial direction.

[0015] The rotating shaft 12 is disposed inside the housing 11. The rotating shaft 12 is disposed along an axis O that is concentric with the housing 11, and is supported by the housing 11 so as to be rotatable about the axis O. A rotor 34 is fixed to the outer periphery of the rotating shaft 12 at a middle position in the axial direction. The rotor 34 has a rotor core (permanent magnet) 35. The rotor core 35 is cylindrical and is fixed to the outer periphery of the rotating shaft 12.

[0016] The inner and outer circumferential surfaces of the stator 31 and rotor 34 face each other in the radial direction. A gap is provided between the inner and outer circumferential surfaces of the stator 31 and rotor 34. Therefore, when a current flows through the stator coil 33 of the stator 31, the rotor 34 rotates due to the attractive and repulsive forces of the generated magnetic force, and the rotating shaft 12 outputs a rotational force.

[0017] The rotating shaft 12 is rotatably supported in the housing 11 by a low-pressure-side air bearing 15 and a high-pressure-side air bearing 16. The rotating shaft 12 has a low-pressure-side shaft portion 12a on one axial side of the rotor 34 and a high-pressure-side shaft portion 12b on the other axial side of the rotor 34. A low-pressure-side bearing sleeve 36 is integrally rotatably attached to the low-pressure-side shaft portion 12a of the rotating shaft 12, and a high-pressure-side bearing sleeve 37 is integrally rotatably attached to the high-pressure-side shaft portion 12b. The low-pressure-side bearing sleeve 36 functions as the low-pressure-side shaft portion, and the high-pressure-side bearing sleeve 37 functions as the high-pressure-side shaft portion. Note that the low-pressure-side bearing sleeve 36 and the high-pressure-side bearing sleeve 37 may be eliminated, and the rotating shaft 12 may be directly supported by the low-pressure-side air bearing 15 and the high-pressure-side air bearing 16.

[0018] Low-pressure side air bearing 15 is provided integrally with low-pressure side bearing housing 22. Low-pressure side air bearing 15 is cylindrical and extends from the inner surface of low-pressure side bearing housing 22 towards rotor 34. Low-pressure side air bearing 15 is disposed outward of low-pressure side bearing sleeve 36 attached to rotating shaft 12. A low-pressure side gap is secured between the inner circumferential surface of low-pressure side air bearing 15 and the outer circumferential surface of low-pressure side bearing sleeve 36.

[0019] High-pressure side air bearing 16 is provided integrally with high-pressure side bearing housing 23. High-pressure side air bearing 16 is cylindrical and extends from the inner surface of high-pressure side bearing housing 23 toward rotor 34. High-pressure side air bearing 16 is disposed outward of high-pressure side bearing sleeve 37 attached to rotating shaft 12. A high-pressure side gap is secured between the inner circumferential surface of high-pressure side air bearing 16 and the outer circumferential surface of high-pressure side bearing sleeve 37.

[0020] In housing 11, low-pressure compressor 41 is disposed on the low-pressure side bearing housing 22 side, and high-pressure compressor 42 is disposed on the high-pressure side bearing housing 23 side. Low-pressure compressor 41 has a low-pressure side housing 43 and a low-pressure wheel 13. High-pressure compressor 42 has a high-pressure side housing 44 and a high-pressure wheel 14.

[0021] The low-pressure side housing 43 is fastened to the outer surface of the low-pressure side bearing housing 22 by a plurality of bolts. The low-pressure wheel 13 is disposed inside the low-pressure side housing 43. The low-pressure wheel 13 is fixed to one axial end of the rotating shaft 12 by bolts 45 so as to be rotatable integrally therewith. The low-pressure compressor 41 is provided with a suction port 46, a diffuser 47, a scroll portion 48 having a spiral shape, and a discharge port (not shown) by the low-pressure side housing 43 and the low-pressure wheel 13.

[0022] The high-pressure side housing 44 is fastened to the outer surface of the high-pressure side bearing housing 23 with a plurality of bolts. The high-pressure wheel 14 is disposed inside the high-pressure side housing 44. The high-pressure wheel 14 is fixed to the other axial end of the rotating shaft 12 with bolts 49 so as to be rotatable together. The high-pressure compressor 42 is provided with a suction port 50, a diffuser 51, a scroll portion 52 having a spiral shape, and a discharge port (not shown) by the high-pressure side housing 44 and the high-pressure wheel 14.

[0023] Furthermore, the low-pressure compressor 41 and the high-pressure compressor 42 have their discharge ports (not shown) and suction ports 50 connected by a connecting flow path 53 .

[0024] When the low-pressure wheel 13 rotates, the low-pressure compressor 41 draws in external air through an inlet 46 and accelerates it due to the centrifugal force of the low-pressure wheel 13. The accelerated air is decelerated and pressurized by the diffuser 47, then flows through the scroll section 48 and is discharged from the discharge port. The low-pressure air compressed by the low-pressure compressor 41 is delivered to the high-pressure compressor 42 through a connecting flow path 53. When the high-pressure wheel 14 rotates, the high-pressure compressor 42 draws in external air through an inlet 50 and accelerates it due to the centrifugal force of the high-pressure wheel 14. The accelerated air is decelerated and pressurized by the diffuser 51, then flows through the scroll section 52 and is discharged from the discharge port.

[0025] <First air flow path> Figure 2 shows First Air Flow Path 1, which is a cross-sectional view taken along line II-II of FIG. 1. FIG. First Air Flow Path 3 is a cross-sectional view of FIG. 1 taken along line III-III.

[0026] 1 and 2, first air flow path 17 supplies compressed air from housing 11 to low-pressure-side air bearing 15. Only one first air flow path 17 is provided in housing 11, but multiple first air flow paths 17 may be provided. First air flow path 17 is provided along the radial direction of rotating shaft 12 in housing 11.

[0027] That is, the low-pressure side bearing housing 22 is provided with one (or multiple) first air flow passages 17 along the radial direction. An air inlet 61 is provided at one end on the radially outer side of the first air flow passage 17. An bleed air flow passage 62 branching from the connecting flow passage 53 is connected to the air inlet 61. In the first air flow passage 17, a portion of the low-pressure air (compressed air) discharged from the low-pressure compressor 41 is bled by the bleed air flow passage 62 and supplied to the air inlet 61. Note that the air inlet 61 may be connected to a bleed air flow passage that bleeds the high-pressure air (compressed air) discharged from the high-pressure compressor 42. The low-pressure side bearing housing 22 is provided with a low-pressure side space 63 around the outer periphery of the axis O. The other end on the radially inner side of the first air flow passage 17 communicates with the low-pressure side space 63.

[0028] A thrust disk 64 constituting a thrust bearing is fixed to the rotating shaft 12. The thrust disk 64 is fixed between the low-pressure side bearing sleeve 36 and the low-pressure wheel 13 on the rotating shaft 12. The thrust disk 64 rotates integrally with the rotating shaft 12. The thrust disk 64 is arranged in a low-pressure side space portion 63. By arranging the thrust disk 64 in the low-pressure side space portion 63, the low-pressure side bearing housing 22 is formed with a low-pressure side annular flow path 63a, a one-face side annular passage 63b, and an other-face side annular passage 63c. The low-pressure side annular flow path 63a, the one-face side annular passage 63b, and the other-face side annular passage 63c are continuous in the circumferential direction. The low-pressure side annular flow path 63a is provided on the outer circumferential side of the thrust disk 64 in the low-pressure side space portion 63. The one-side annular passage 63b is provided on one side (low-pressure wheel 13 side) of the thrust disk 64 in the low-pressure side space portion 63. The other-side annular passage 63c is provided on the other side (low-pressure side bearing sleeve 36 side) of the thrust disk 64 in the low-pressure side space portion 63. The other-side annular passage 63c communicates with a low-pressure gap between the inner circumferential surface of the low-pressure side air bearing 15 and the outer circumferential surface of the low-pressure side bearing sleeve 36. The low-pressure side bearing housing 22 has an abrasion-resistant coating layer applied to the surfaces facing the one-side annular passage 63b and the other-side annular passage 63c, and cooling is required to protect the abrasion-resistant coating layer.

[0029] Therefore, low-pressure air (hereinafter, compressed air) bled from the connecting passage 53 is sent from the bleed passage 62 to the air intake port 61, flows radially inward through the first air passage 17, and is supplied to the low-pressure-side annular passage 63a (low-pressure-side space portion 63). At this time, the compressed air in the low-pressure-side annular passage 63a is supplied to the one-face-side annular passage 63b and the other-face-side annular passage 63c. As the high-pressure air acts on one and the other faces of the thrust disk 64, the rotating shaft 12 integrated with the thrust disk 64 is supported at a predetermined position in the axial direction. In addition, the wear-resistant coating layer applied to the surfaces of the low-pressure-side bearing housing 22 facing the one-face-side annular passage 63b and the other-face-side annular passage 63c is cooled by the compressed air.

[0030] The compressed air in low-pressure side annular flow path 63a is supplied to low-pressure side air bearing 15 through the other-surface side annular passage 63c. That is, the compressed air is supplied to the low-pressure gap between the inner circumferential surface of low-pressure side air bearing 15 and the outer circumferential surface of low-pressure side bearing sleeve 36, thereby supporting rotating shaft 12 at a predetermined position in the radial direction. The compressed air supplied to low-pressure side air bearing 15 then flows into the gap between stator 31 and rotor 34, cooling stator core 32 and stator coil 33 of stator 31. After cooling stator 31, the compressed air is discharged to the outside from air outlet 95 provided in housing 11.

[0031] As shown in FIGS. 1 and 3 , the low-pressure side bearing housing 22 is provided with a first bypass passage 65. The first bypass passage 65 passes through the one-side annular passage 63b and opens toward the stator coil 33 of the stator 31. The first bypass passage 65 has radial passages 65a, an annular passage 65b, and an axial passage 65c. One end of the radial passage 65a communicates with the one-side annular passage 63b and the other end communicates with the annular passage 65b. A plurality of the radial passages 65a are provided at intervals around the circumferential direction of the low-pressure side bearing housing 22. One end of the axial passage 65c communicates with the annular passage 65b and the other end opens to the inner surface of the low-pressure side bearing housing 22. A plurality of the axial passages 65c are provided at intervals around the circumferential direction of the low-pressure side bearing housing 22.

[0032] Therefore, the compressed air in the one-side annular passage 63b flows through the radial passage 65a, the annular passage 65b and the axial passage 65c of the first bypass passage 65 and is discharged onto the inner surface of the low-pressure side bearing housing 22, thereby cooling the stator coil 33 facing the inner surface of the low-pressure side bearing housing 22.

[0033] <Second air flow path> Figure 4 shows Second Air Flow Path 1 IV-IV cross section, and FIG. 5 is a cross-sectional view of FIG. Second Air Flow Path 2 is a cross-sectional view of FIG. 1 showing the VV cross section.

[0034] 1, 4, and 5, second air flow path 18 branches off from first air flow path 17 and supplies compressed air to high-pressure-side air bearing 16. Only one second air flow path 18 is provided in housing 11, but multiple second air flow paths may be provided. Second air flow path 18 has an axial air flow path 71 and a radial air flow path 72. Axial air flow path 71 branches off from first air flow path 17 and is provided along the axial direction of rotating shaft 12 in housing 11. Radial air flow path 72 communicates with axial air flow path 71 and is provided along the radial direction of rotating shaft 12 in housing 11.

[0035] That is, the motor housing 21 is provided with one axial air flow passage 71 along the axial direction. One end of the axial air flow passage 71 is connected to the branch portion 66 provided in the first air flow passage 17. The high-pressure side bearing housing 23 is provided with one (or multiple) radial air flow passages 72 along the radial direction. One radially outer end of the radial air flow passage 72 is connected to the other end of the axial air flow passage 71. The high-pressure side bearing housing 23 is provided with a high-pressure side annular flow passage 73 around the outer periphery of the axis O. The high-pressure side annular flow passage 73 is provided outward from the end of the high-pressure side bearing sleeve 37 on the high-pressure wheel 14 side. The other radially inner end of the radial air flow passage 72 is connected to the high-pressure side annular flow passage 73. The high-pressure side annular flow passage 73 is connected to a high-pressure gap between the inner circumferential surface of the high-pressure side air bearing 16 and the outer circumferential surface of the high-pressure side bearing sleeve 37.

[0036] Therefore, the compressed air branched from the first air flow path 17 flows axially through the axial air flow path 71 of the second air flow path 18, then flows radially inward through the radial air flow path 72, and is supplied to the high-pressure-side annular flow path 73. The compressed air in the high-pressure-side annular flow path 73 is supplied to the high-pressure-side air bearing 16. That is, the compressed air is supplied to the high-pressure gap between the inner circumferential surface of the high-pressure-side air bearing 16 and the outer circumferential surface of the high-pressure-side bearing sleeve 37, thereby supporting the rotating shaft 12 at a predetermined radial position. The compressed air supplied to the high-pressure-side air bearing 16 then flows into the gap between the stator 31 and the rotor 34, cooling the stator core 32 and stator coil 33 of the stator 31. After cooling the stator 31, the compressed air is discharged to the outside through an air outlet 95 provided in the housing 11.

[0037] <Air flow regulator> 1, the air flow rate regulator 19 regulates the flow rate of compressed air flowing through the first air flow path 17 and the second air flow path 18. The air flow rate regulator 19 is provided in the second air flow path 18.

[0038] The air flow control device 19 has a plurality of air flow control members 81 with different flow path areas. The air flow control members 81 are detachably attached to the housing 11. The air flow control member 81 is, for example, a pipe in which a straight flow path 82 with a circular cross section is formed. A plurality of types of air flow control members 81 are prepared, each with a flow path area of ​​the straight flow path 82 equal to or smaller than the flow path area of ​​the axial air flow path 71 in the second air flow path 18. However, the air flow control member 81 may also be a flow path having a throttle portion with a different flow path area.

[0039] The motor housing 21 is provided at one axial end with a first accommodating recess 83 that communicates with one end of the axial air flow path 71. The low-pressure side bearing housing 22 is provided at its inner surface with a second accommodating recess 84 that communicates with the branch portion 66 of the first air flow path 17. The air flow rate adjusting member 81 is attached to the motor housing 21. The low-pressure side bearing housing 22 When assembled, it is housed in the first air flow passage 17 and the second housing recess 84 .

[0040] electric When assembling the dynamic compressor 10, an air flow rate adjusting member 81 having a straight flow path 82 with an optimum flow path area is selected and assembled. The compressed air taken into the housing 11 is supplied to the low-pressure side of the stator 31 through the first air flow path 17 and the low-pressure side air bearing 15, thereby cooling the low-pressure side of the stator coil 33. The compressed air is also supplied to the high-pressure side of the stator 31 through the second air flow path 18 branching from the first air flow path 17 and the high-pressure side air bearing 16, thereby cooling the high-pressure side of the stator coil 33.

[0041] The inner surfaces of low-pressure side air bearing 15 and high-pressure side air bearing 16 are coated with a wear-resistant coating, and it is necessary to cool the inner surfaces of low-pressure side air bearing 15 and high-pressure side air bearing 16 to below the heat-resistant temperature of the coating. Air flow rate regulator 19 adjusts the flow rate of compressed air so that the inner surface temperatures of low-pressure side air bearing 15 and high-pressure side air bearing 16 remain below the heat-resistant temperature.

[0042] Furthermore, the temperature of the stator 31 rises due to the current flowing through the stator coil 33. The air flow control device 19 adjusts the flow rate of compressed air so that the temperatures of the low-voltage side coil end 33a and the high-voltage side coil end 33b of the stator coil 33 are within an appropriate temperature range.

[0043] Specifically, air flow control device 19 adjusts the flow rate of compressed air so that the inner surface temperatures of low-pressure side air bearing 15 and high-pressure side air bearing 16 are below their heat-resistant temperatures and so that the temperatures of low-pressure side coil end 33a and high-pressure side coil end 33b of stator coil 33 are within an appropriate temperature range. In electric compressor 10, the temperatures of high-pressure side bearing sleeve 37 and high-pressure side coil end 33b tend to be higher than the temperatures of low-pressure side bearing sleeve 36 and low-pressure side coil end 33a. Therefore, air flow control device 19 adjusts the flow rate of compressed air by selecting air flow control member 81 so that the amount of compressed air flowing through second air flow path 18 is greater than the amount of compressed air flowing through first air flow path 17. In this case, the flow rate of compressed air is adjusted taking into consideration the balance between the inner surface temperatures of low-pressure side air bearing 15 and high-pressure side air bearing 16 and the balance between the temperatures of low-pressure side coil end 33a and high-pressure side coil end 33b of stator coil 33.

[0044] Therefore, the compressed air is supplied to the low-pressure side annular flow path 63a (low-pressure side space portion 63) through the first air flow path 17, and then to the low-pressure side air bearing 15 through the other surface side annular passage 63c. Here, the low-pressure side air bearing 15 and the low-pressure side bearing sleeve 36 are cooled by the compressed air.

[0045] Meanwhile, the compressed air branched from the first air flow path 17 passes through the axial air flow path 71 and the radial air flow path 72 of the second air flow path 18 and is supplied to the high-pressure-side annular flow path 73, and then to the high-pressure-side air bearing 16. Here, the compressed air cools the high-pressure-side air bearing 16 and the high-pressure-side bearing sleeve 37. The compressed air then flows into the gap between the stator 31 and the rotor 34, cooling the stator 31.

[0046] At this time, air flow rate regulator 19 adjusts the flow rate of compressed air flowing through second air flow path 18 so as to be limited, thereby also adjusting the flow rate of compressed air flowing through first air flow path 17. As a result, low-pressure side air bearing 15 and low-pressure side bearing sleeve 36, and high-pressure side air bearing 16 and high-pressure side bearing sleeve 37 are cooled to appropriate temperatures. Also, high-pressure side coil end 33b and low-pressure side coil end 33a of stator coil 33 are cooled to appropriate temperatures.

[0047] [Second embodiment] 6 is a vertical cross-sectional view showing the internal configuration of an electric compressor according to the second embodiment. Note that members having the same functions as those in the first embodiment described above are given the same reference numerals and detailed descriptions thereof will be omitted.

[0048] As shown in FIG. 6, the electric compressor 10A includes a housing 11, a rotating shaft 12, a low-pressure wheel 13, a high-pressure wheel 14, a low-pressure side air bearing 15, a high-pressure side air bearing 16, a first air flow path 17, a second air flow path 18, and an air flow control device 19, and the basic configuration is the same as that of the first embodiment.

[0049] The low-pressure side bearing housing 22 is provided with a first bypass flow path 65 and a second bypass flow path 91. The first bypass flow path 65 passes through the one-face annular passage 63b and opens onto the inner surface of the low-pressure side bearing housing 22 toward the stator coil 33 of the stator 31. The second bypass flow path 91 passes through the other-face annular passage 63c and opens onto the inner surface of the low-pressure side bearing housing 22 toward the stator coil 33 of the stator 31. In this case, the first bypass flow path 65 opens towards the coil end on the radially middle side of the stator coil 33, and the second bypass flow path 91 opens towards the coil end on the radially inner side of the stator coil 33. A plurality of second bypass flow paths 91 are provided at intervals around the circumferential direction of the low-pressure side bearing housing 22.

[0050] Therefore, the compressed air in the low-pressure-side annular flow path 63a is discharged from the one-face-side annular passage 63b through the first bypass flow path 65 toward the stator coil 33. The compressed air in the low-pressure-side annular flow path 63a is also supplied from the other-face-side annular passage 63c to a low-pressure gap between the low-pressure-side air bearing 15 and the low-pressure-side bearing sleeve 36, and is also discharged through the second bypass flow path 91 toward the stator coil 33. That is, with respect to the thrust disk 64, the compressed air in the one-face-side annular passage 63b is discharged toward the stator coil 33 through the first bypass flow path 65, and the compressed air in the other-face-side annular passage 63c is discharged toward the stator coil 33 through the second bypass flow path 91. This equalizes the pressure in the one-face-side annular passage 63b and the pressure in the other-face-side annular passage 63c, equalizing the load on one side and the load on the other side of the thrust disk 64, and reducing the thrust force acting on the rotating shaft 12.

[0051] The compressed air in the other-surface annular passage 63c is supplied to the low-pressure gap between the low-pressure side air bearing 15 and the low-pressure side bearing sleeve 36. Therefore, the number and flow path area of ​​the second bypass flow paths 91 must be considered so as not to reduce the flow rate of compressed air required by the low-pressure side air bearing 15 and the low-pressure side bearing sleeve 36.

[0052] [Third embodiment] 7 is a vertical cross-sectional view showing the internal configuration of an electric compressor according to the third embodiment. Note that members having the same functions as those in the first embodiment described above are given the same reference numerals and detailed description thereof will be omitted.

[0053] As shown in FIG. 7, the electric compressor 10B includes a housing 11, a rotating shaft 12, a low-pressure wheel 13, a high-pressure wheel 14, a low-pressure side air bearing 15, a high-pressure side air bearing 16, a first air flow path 17, a second air flow path 18, and an air flow control device 19, and the basic configuration is the same as that of the first embodiment.

[0054] The high-pressure side bearing housing 23 is provided with a third bypass flow path 92. The third bypass flow path 92 branches off from the second air flow path 18 and opens toward the stator 31. One end of the third bypass flow path 92 communicates with a connection portion of the second air flow path 18 between the axial air flow path 71 and the radial air flow path 72. It is sufficient that one end of the third bypass flow path 92 is connected to at least one of the axial air flow path 71 and the radial air flow path 72. The other end of the third bypass flow path 92 opens on the inner surface of the high-pressure side bearing housing 23 toward the stator coil 33 of the stator 31. In this case, the third bypass flow path 92 opens toward the coil end on the radially outer peripheral side of the stator coil 33. A plurality of third bypass flow paths 92 are provided at intervals around the circumferential direction of the high-pressure side bearing housing 23.

[0055] Therefore, the compressed air branched to the second air flow path 18 is supplied to the high-pressure-side annular flow path 73 through the axial air flow path 71 and the radial air flow path 72, and then supplied to the high-pressure-side air bearing 16. In addition, the compressed air branched to the second air flow path 18 branches from the axial air flow path 71 to the third bypass flow path 92, and is discharged by the third bypass flow path 92 toward the high-pressure-side coil end 33b of the stator coil 33, cooling the high-pressure-side coil end 33b.

[0056] In electric compressor 10B, the high-pressure compressor 42 compresses low-pressure air into high-pressure air, which tends to increase the temperature of high-pressure coil end 33b of stator coil 33. Therefore, by guiding compressed air to high-pressure coil end 33b of stator coil 33 through third bypass flow path 92, the high-temperature coil end is actively cooled and the temperature rise is suppressed.

[0057] In addition, the electric compressor 10B is provided with a first bypass flow path 65 in the low-pressure side bearing housing 22, and the compressed air is supplied from the first bypass flow path 65 to the low-pressure side coil end 33a of the stator coil 33 for cooling. Temperature of low-voltage side coil end 33a The number and flow path area of ​​the third bypass flow paths 92 are set so that the temperature of the high pressure side coil end 33b becomes an appropriate temperature.

[0058] [Fourth embodiment] 8 is a vertical cross-sectional view showing the internal configuration of an electric compressor according to the fourth embodiment. Note that members having the same functions as those in the first embodiment described above are given the same reference numerals and detailed descriptions thereof will be omitted.

[0059] As shown in FIG. 8, the electric compressor 10C includes a housing 11, a rotating shaft 12, a low-pressure wheel 13, a high-pressure wheel 14, a low-pressure side air bearing 15, a high-pressure side air bearing 16, a first air flow path 17, a second air flow path 18, and an air flow control device 19, and the basic configuration is the same as that of the first embodiment.

[0060] The electric compressor 10C has a third air flow path 93. The third air flow path 93 supplies compressed air to the gap between the stator 31 and the rotor 34. The third air flow path 93 has an air supply port 94 and an air discharge port 95. The motor housing 21 has the air supply port 94 on the high-pressure side bearing housing 23 side. The motor housing 21 has the air discharge port 95 on the low-pressure side bearing housing 22 side. The air supply port 94 is connected to an air extraction flow path 96 branching from the connecting flow path 53. The third air flow path 93 is a flow path through which compressed air flows from the air supply port 94 through the high-pressure side coil end 33b of the stator coil 33, the gap between the stator core 32 and the rotor 34, and the low-pressure side coil end 33a and is discharged from the air discharge port 95. One third air flow path 93 (air supply port 94, air discharge port 95) may be provided around the motor housing 21, or multiple third air flow paths 93 may be provided at intervals around the circumferential direction.

[0061] Therefore, the compressed air taken into the housing 11 from the air intake port 61 is supplied to the low-pressure side air bearing 15 and the thrust disk 64 through the first air flow path 17, and to the high-pressure side air bearing 16 through the second air flow path 18, thereby mainly cooling the low-pressure side air bearing 15 and the high-pressure side air bearing 16. The compressed air taken into the housing 11 from the air supply port 94 is supplied to the stator 31 and the rotor 34, thereby mainly cooling the stator 31 and the rotor 34. Cooled The compressed air and the compressed air that has cooled the stator 31 and the rotor 34 join together and are discharged to the outside from the air outlet 95. The compressed air that has flowed through the first air flow path 17 and the second air flow path 18 is also discharged from the air outlet 95.

[0062] [Effects of this embodiment] The electric compressor of the first aspect comprises a housing 11 having a cylindrical stator 31, a rotating shaft 12 having a rotor 34 arranged inside the housing 11 and facing the stator 31, a low-pressure wheel 13 fixed to one axial end of the rotating shaft 12, a high-pressure wheel 14 fixed to the other axial end of the rotating shaft 12, a low-pressure side air bearing 15 that rotatably supports the low-pressure side shaft portion 12a of the rotating shaft 12 in the housing 11, a high-pressure side air bearing 16 that rotatably supports the high-pressure side shaft portion 12b of the rotating shaft 12 in the housing 11, a first air flow path 17 that supplies compressed air from the housing 11 to either the low-pressure side air bearing 15 or the high-pressure side air bearing 16, a second air flow path 18 that branches off from the first air flow path 17 and supplies air to the other of the low-pressure side air bearing 15 or the high-pressure side air bearing 16, and an air flow control device 19 that adjusts the flow rate of compressed air flowing through the first air flow path 17 and the second air flow path 18.

[0063] In the electric compressor according to the first aspect, compressed air is supplied to low-pressure-side air bearing 15 through first air flow path 17, and is supplied to high-pressure-side air bearing 16 through second air flow path 18 branching from first air flow path 17. This eliminates the need for an annular flow path or the like in housing 11 to temporarily store compressed air, simplifying the structure and reducing pressure loss of the compressed air, allowing low-pressure-side air bearing 15 and high-pressure-side air bearing 16 to function properly. Furthermore, the flow rate of the compressed air flowing through first air flow path 17 and second air flow path 18 is adjusted by air flow regulator 19. This allows an appropriate amount of compressed air to be supplied to low-pressure-side air bearing 15 and high-pressure-side air bearing 16, allowing low-pressure-side air bearing 15 and high-pressure-side air bearing 16 to function properly and allowing low-pressure-side air bearing 15 and high-pressure-side air bearing 16 to be appropriately cooled.

[0064] In the electric compressor according to the second aspect, only one first air flow path 17 and one second air flow path 18 are provided in the housing 11. This reduces the pressure loss of the compressed air, allowing the low-pressure side air bearing 15 and the high-pressure side air bearing 16 to function properly.

[0065] In the electric compressor according to the third aspect, first air flow path 17 is provided along the radial direction of rotating shaft 12 in housing 11, and second air flow path 18 is provided including axial air flow path 71 branching from first air flow path 17 and provided along the axial direction of rotating shaft 12 in housing 11, and radial air flow path 72 communicating with axial air flow path 71 and provided along the radial direction of rotating shaft 12 in housing 11. This makes it possible to simplify second air flow path 18, reduce pressure loss of compressed air, and appropriately supply compressed air to high-pressure-side air bearing 16.

[0066] In the electric compressor according to the fourth aspect, an air flow rate control device 19 is provided in at least one of the first air flow path 17 and the second air flow path 18. As a result, by adjusting the flow rate of one of the first air flow path 17 and the second air flow path 18 with the air flow rate control device 19, it is possible to adjust the flow rate of the other air flow path, thereby simplifying the structure.

[0067] The electric compressor according to the fifth aspect is provided with an air flow rate adjustment member 81 having a predetermined flow path area as the air flow rate control device 19, and the air flow rate adjustment member 81 is detachable from the housing 11. As a result, by attaching the air flow rate adjustment member 81 having an optimal flow path area to the housing 11 in accordance with the configuration of the electric compressor 10, 10A, 10B, 10C, it is possible to appropriately adjust the flow rates of the first air flow path 17 and the second air flow path 18.

[0068] The electric compressor according to the sixth aspect includes a thrust disk 64 fixed to the rotating shaft 12 on the side of the low-pressure wheel 13 or the side of the high-pressure wheel 14, a first bypass flow path 65 branching from the first air flow path 17, passing through one side of the thrust disk 64 and opening toward the stator 31, and a second bypass flow path 91 branching from the first air flow path 17, passing through the other side of the thrust disk 64 and opening toward the stator 31. This equalizes the pressure on one side of the thrust disk 64 and the pressure on the other side, thereby leveling out the load on one side of the thrust disk 64 and the load on the other side, making it possible to reduce the thrust force acting on the rotating shaft 12.

[0069] In the electric compressor according to the seventh aspect, second air flow path 18 supplies compressed air to high-pressure side air bearing 16, and third bypass flow path 92 is provided, branching from second air flow path 18 and opening toward stator 31. In this way, compressed air is actively supplied from second air flow path 18 to high-pressure side coil end 33b of stator coil 33, thereby making it possible to appropriately cool high-pressure side coil end 33b, which is relatively prone to becoming hot.

[0070] The electric compressor according to the eighth aspect is provided with a third air flow path 93 that supplies compressed air from the housing 11 to the gap between the stator 31 and the rotor 34, separate from the first air flow path 17 and the second air flow path 18. As a result, the first air flow path 17 and the second air flow path 18 supply compressed air to the low-pressure side air bearing 15 and the high-pressure side air bearing 16 to cool them. On the other hand, the third air flow path 93 supplies compressed air to the stator 31 and the rotor 34 to cool them. Therefore, by cooling the low-pressure side air bearing 15, the high-pressure side air bearing 16, the stator 31, and the rotor 34 with dedicated compressed air, it is possible to improve cooling performance.

[0071] In the above-described embodiment, the first air flow path 17 is provided in the low-pressure side bearing housing 22, and the second air flow path 18 is provided in the motor housing 21 and the high-pressure side bearing housing 23, but this configuration is not limited to this. The first air flow path 17 may be provided in the high-pressure side bearing housing 23, and the second air flow path 18 may be provided in the motor housing 21 and the low-pressure side bearing housing 22. [Explanation of symbols]

[0072] 10, 10A, 10B, 10C Electric compressor 11. Housing 12 Rotation axis 12a Low pressure side shaft 12b High-pressure side shaft 13 Low pressure wheels 14 High-pressure wheels 15 Low-pressure air bearing 16 High-pressure side air bearing 17 First air flow path 18 Second air flow path 19 Air flow regulator 21 Motor housing 22 Low pressure side bearing housing 23 High pressure side bearing housing 31 Stator 32 Stator core 33 stator coil 33a Low voltage side coil end 33b High pressure side coil end 34 rotor 35 rotor core 36 Low pressure side bearing sleeve 37 High pressure side bearing sleeve 41 Low-pressure compressor 42 High-pressure compressor 43 Low pressure side housing 44 High pressure side housing 45,49 volts 46,50 intake port 47,51 Diffuser 48,52 Scroll section 53 Connecting Channel 61 Air intake 62 Bleed passage 63 Low pressure side space 63a Low pressure side annular flow passage 63b One-way circular passage 63c Other side circular passage 64 Thrust disc 65 First bypass flow path 65a Radial flow passage 65b Annular flow path 65c Axial flow path 66 Branch 71 Axial air passage 72 Radial air flow passage 73 High pressure side annular flow passage 81 Air flow control member 82 Straight flow path 83 First storage recess 84 Second storage recess 91 Second bypass flow path 92 Third bypass flow path 93 Third air flow path 94 Air supply port 95 Air exhaust port 96 Bleed passage

Claims

1. a housing having a cylindrical stator; a rotating shaft having a rotor disposed inside the housing and facing the stator; a low-pressure wheel fixed to one side of the rotation shaft in the axial direction; a high-pressure wheel fixed to the other axial end of the rotary shaft; a low-pressure side air bearing that rotatably supports a low-pressure side shaft portion of the rotary shaft in the housing; a high-pressure side air bearing that rotatably supports a high-pressure side shaft portion of the rotary shaft in the housing; a first air flow path that supplies compressed air from the housing to one of the low-pressure side air bearing and the high-pressure side air bearing; a second air flow path branching from the first air flow path and supplying air to the other of the low-pressure side air bearing and the high-pressure side air bearing; an air flow rate adjusting device that adjusts the flow rate of compressed air flowing through the first air flow path and the second air flow path; Equipped with the first air flow path is provided along a radial direction of the rotation shaft in the housing, and the second air flow path has an axial air flow path branching from the first air flow path and provided along the axial direction of the rotation shaft in the housing, and a radial air flow path communicating with the axial air flow path and provided along the radial direction of the rotation shaft in the housing. Electric compressor.

2. a housing having a cylindrical stator; a rotating shaft having a rotor disposed inside the housing and facing the stator; a low-pressure wheel fixed to one side of the rotation shaft in the axial direction; a high-pressure wheel fixed to the other axial end of the rotary shaft; a low-pressure side air bearing that rotatably supports a low-pressure side shaft portion of the rotary shaft in the housing; a high-pressure side air bearing that rotatably supports a high-pressure side shaft portion of the rotary shaft in the housing; a first air flow path that supplies compressed air from the housing to one of the low-pressure side air bearing and the high-pressure side air bearing; a second air flow path branching from the first air flow path and supplying air to the other of the low-pressure side air bearing and the high-pressure side air bearing; an air flow rate adjusting device that adjusts the flow rate of compressed air flowing through the first air flow path and the second air flow path; Equipped with a thrust disk fixed to the low-pressure wheel side or the high-pressure wheel side of the rotary shaft; a first bypass flow path branching from the first air flow path, passing through one side of the thrust disk and opening toward the stator; and a second bypass flow path branching from the first air flow path, passing through the other side of the thrust disk and opening toward the stator. Electric compressor.

3. Only one of the first air flow path and the second air flow path is provided in the housing. The electric compressor according to claim 1 or 2.

4. The air flow rate adjusting device is provided in at least one of the first air flow path and the second air flow path. The electric compressor according to any one of claims 1 to 3.

5. the air flow rate adjusting device has an air flow rate adjusting member having a predetermined flow path area, and the air flow rate adjusting member is detachably provided to the housing. The electric compressor according to any one of claims 1 to 4.

6. the second air flow path supplies compressed air to the high-pressure side air bearing, and includes a third bypass flow path branching from the second air flow path and opening toward the stator. The electric compressor according to any one of claims 1 to 5.

7. a third air flow path that supplies compressed air from the housing to a gap between the stator and the rotor, separate from the first air flow path and the second air flow path; The electric compressor according to any one of claims 1 to 6.

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