A turbo compressor with the motor located upstream of the compressed gas flow path.

Abstract

The present invention relates to a turbocompressor, comprising: a motor having a rotating shaft connected at one end to an impeller to rotate the impeller; a housing having a motor accommodation space for accommodating the motor; and a cooling air passage extending through the motor accommodation space and allowing a cooling gas accommodated therein to flow, wherein a compressed gas inlet is located at the front end of the housing, the impeller is located at the rear end of the housing, the motor is disposed between the compressed gas inlet and the impeller, the rotating shaft has a hollow extending along its longitudinal direction, and the cooling air passage includes a first cooling air passage starting from the compressed gas inlet, passing through the outer circumferential surface of the rotating shaft to the impeller, and a second cooling air passage starting from the compressed gas inlet, passing through the hollow of the rotating shaft to the impeller, wherein gas drawn through the compressed gas inlet by the suction force of the impeller passes through the first and second cooling air passages to cool the motor. This invention has the advantage that the stator and rotor of the motor can be rapidly cooled using the relatively low-temperature cooling gas drawn through the compressed gas inlet.

Description

【Technical Field】 【0001】 The present invention relates to a turbo compressor, and particularly to a turbo compressor capable of quickly cooling a stator and a rotor of a motor using a relatively low-temperature cooling gas inhaled from a compressed gas suction port. 【Background Art】 【0002】 A turbo compressor or a turbo blower is a centrifugal pump that sucks and compresses external air or gas by rotating an impeller at high speed and then blows it out externally. It is widely used for powder transfer and aeration in sewage treatment plants, etc. Recently, it is also used for industrial processes and automotive applications. 【0003】 In such a turbo compressor, high frictional heat is generated between the motor and the bearings due to the high-speed rotation of the impeller. Therefore, cooling of the motor and the bearings, which are the main heat sources, is necessary. 【0004】 An example of a conventional turbo compressor is shown in FIG. 6. This turbo compressor 1 has a structure in which an impeller 51 is disposed in front of a motor 20. After a part of the compressed air compressed by the impeller 51 flows into the space in which the motor 20 is housed, first, the stator 23 of the motor 20 is cooled, and then, while passing through the hollow portion in the rotating shaft 24 through a hole formed at the rear end portion of the rotating shaft 24, the permanent magnet 22, which is a rotor coupled to the rotating shaft 24, is cooled. 【0005】 The air that has cooled the permanent magnet 22 in this way is discharged to the front portion of the rotating shaft 24 through a hole formed at the front end portion of the rotating shaft 24, and then flows into the impeller 51 again and is recompressed. 【0006】 In such a conventional turbo compressor 1, the air compressed by the impeller 51 is already at a high temperature during the compression process. However, after this hot air cools the stator 23 of the motor 20, its temperature rises even further. As a result, this even hotter air cools the permanent magnets 22, which are the rotor of the motor 20, thus reducing the cooling performance of both the stator 23 and the rotor 22 of the motor 20. 【0007】 In particular, such problems become even more serious when the motor 20 rotates at high speed. If the heat generated by a high-speed rotating motor cannot be efficiently cooled, there is a risk that the performance of the entire motor will deteriorate due to demagnetization or performance degradation of the permanent magnets 22 used as rotors. 【0008】 Furthermore, conventional turbo compressors 1 use a portion of the air compressed by the impeller 51 to cool the motor 20, and after the air used for cooling is heated, it flows back into the upstream side of the impeller 51 and is recompressed, creating a "vortex flow." This may reduce the compression efficiency of the air that is ultimately discharged through the compressed air outlet 55. [Overview of the project] [Problems that the invention aims to solve] 【0009】 The present invention was devised to solve the above problems, and its objective is to provide a turbo compressor with an improved structure that can rapidly cool the stator and rotor of a motor using a relatively low-temperature cooling gas drawn in from a compressed gas inlet. [Means for solving the problem] 【0010】 To achieve the above objective, the turbo compressor according to the present invention is a turbo compressor capable of compressing a gas and supplying it to the outside, comprising: a compressed gas inlet into which the gas is drawn; an impeller for compressing the gas that has flowed in through the compressed gas inlet; a compressed gas outlet from which the gas compressed by the impeller is discharged to the outside; a compression unit having a compressed gas flow path connected from the compressed gas inlet to the compressed gas outlet; a motor having a rotating shaft with one end coupled to the impeller for rotating the impeller; a housing having a motor housing space for housing the motor; and a cooling gas provided to pass through the motor housing space and formed to allow flow of the cooling gas contained inside. The motor includes a cooling air passage, the compressed gas intake is located at the front end of the housing, the impeller is located at the rear end of the housing, the motor is located between the compressed gas intake and the impeller, the rotating shaft includes a hollow extending along its longitudinal direction, the cooling air passage includes a first cooling air passage starting from the compressed gas intake and passing through the outer circumferential surface of the rotating shaft to the impeller, and a second cooling air passage starting from the compressed gas intake and passing through the hollow of the rotating shaft to the impeller, wherein the gas drawn in from the compressed gas intake by the suction force of the impeller cools the motor as it passes through the first and second cooling air passages. 【0011】 Here, it is desirable that the first cooling air passage and the second cooling air passage are formed so that the cooling gas flows in one direction from the compressed gas intake to the impeller. 【0012】 In this case, it is desirable that the first cooling air passage is formed to cool the stator of the motor. 【0013】 Here, it is desirable that the second cooling air passage be formed to cool the rotor of the motor. 【0014】 Here, it is desirable that the front end of the housing has at least one first through-hole provided for the gas drawn in from the compressed gas intake to flow into the motor housing space, and that the rear end of the housing has at least one second through-hole provided for the gas housed in the motor housing space to flow into the impeller. 【0015】 Here, it is desirable that at least one of the first through-hole and the second through-hole is arranged in multiples at predetermined intervals along the circumferential direction of the rotation axis. 【0016】 Here, it is desirable to include a third cooling air passage that includes a thrust bearing located at the front end of the rotating shaft, and that starts from the compressed gas intake, passes through the thrust bearing, and reaches the impeller. 【0017】 Here, it is desirable that at least one third through-hole is formed at the front end of the housing, which is provided so that the gas drawn in from the compressed gas intake port flows into the thrust bearing. 【0018】 Here, it is desirable that the third through-hole includes an annular hole formed by the cooperation of a circular hole formed at the front end of the housing and the front end of the rotating shaft positioned in the circular hole. 【0019】 Here, the rotating shaft includes a gas inlet hole formed at the front end of the rotating shaft and communicating with the hollow of the rotating shaft; and a gas outlet hole formed at the rear end of the rotating shaft and communicating with the hollow of the rotating shaft, wherein the gas outlet hole is preferably located between the stator of the motor and the impeller. [Effects of the Invention] 【0020】 According to the present invention, a turbo compressor capable of compressing a gas and supplying it to the outside comprises: a compressed gas inlet into which the gas is drawn; an impeller for compressing the gas flowing in through the compressed gas inlet; a compressed gas outlet from which the gas compressed by the impeller is discharged to the outside; a compression unit having a compressed gas flow path connected from the compressed gas inlet to the compressed gas outlet; a motor having a rotating shaft with one end coupled to the impeller for rotating the impeller; a housing having a motor housing space for housing the motor; and a cooling air passage provided to pass through the motor housing space and formed to allow flow of cooling gas contained inside; wherein the compressed gas inlet is located at the front end of the housing. The impeller is positioned at the rear end of the housing, the motor is positioned between the compressed gas intake and the impeller, the rotating shaft includes a hollow extending along its longitudinal direction, and the cooling air passage includes a first cooling air passage starting from the compressed gas intake and passing through the outer surface of the rotating shaft to the impeller; and a second cooling air passage starting from the compressed gas intake and passing through the hollow of the rotating shaft to the impeller. The gas drawn in from the compressed gas intake by the suction force of the impeller cools the motor as it passes through the first and second cooling air passages, thus providing the effect of rapidly cooling the stator and rotor of the motor using the relatively low-temperature cooling gas drawn in from the compressed gas intake. [Brief explanation of the drawing] 【0021】 [Figure 1] This is a cross-sectional view of a turbo compressor according to one embodiment of the present invention. [Figure 2] Figure 1 is a magnified view of a section of the turbo compressor shown. [Figure 3] Figure 2 is a magnified view of the front end of the turbo compressor shown. [Figure 4] Figure 2 is a magnified view of the rear end of the turbo compressor shown. [Figure 5] Figure 1 is a cross-sectional view of the axis of rotation and its surroundings. [Figure 6] This is a cross-sectional view of a conventional turbo compressor. 【Mode for Carrying Out the Invention】 【0022】 Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. 【0023】 FIG. 1 is a cross-sectional view of a turbo compressor according to an embodiment of the present invention, and FIG. 2 is a partially enlarged view of the turbo compressor shown in FIG. 1. FIG. 3 is a partially enlarged view of the front end portion of the turbo compressor shown in FIG. 2. 【0024】 Referring to FIGS. 1 to 3, a turbo compressor 100 according to a preferred embodiment of the present invention is a centrifugal pump that sucks and compresses external gas by rotating an impeller at high speed and then blows the gas to the outside, and is also referred to as a so-called turbo compressor or turbo blower. This turbo compressor 100 includes a housing 10, a compression unit 20, a motor 30, and a cooling air passage. Hereinafter, it is assumed that the gas to be compressed is air. 【0025】 The housing 10 is a housing made of a metal material, and is a cylindrical member having a motor accommodation space 13 inside, having a cross section with a first central axis C1 as the center of a circle, and extending along the first central axis C1. 【0026】 The motor accommodation space 13 is a space having a shape corresponding to the motor 30 so as to accommodate the motor 30 described later. 【0027】 At the rear end portion of the housing 10, as shown in FIG. 2, an impeller 21 of the compression unit 20 is disposed. 【0028】 The housing 10 is separately manufactured into a plurality of components for mounting the motor 30. In the present embodiment, the housing 10 includes a first housing 10a, a second housing 10b, a third housing 10c, and a fourth housing 10d. 【0029】 The first housing 10a is a cylindrical member having a cross-section with the first central axis C1 as the center of the circle. 【0030】 At the rear end of the first housing 10a, at least one second through-hole 12 is formed, which is provided so that the gas contained in the motor housing space 13 flows into the impeller 21. 【0031】 In this embodiment, a plurality of second through holes 12 are provided and are arranged at predetermined intervals along the circumferential direction of the rotating shaft 31, which will be described later. 【0032】 The second through-hole 12 can be formed in various shapes, such as a circular hole, a slit-shaped hole extending along the radial direction of the rotation axis 31, or a fan-shaped hole that becomes narrower as it approaches the rotation axis 31. 【0033】 In this embodiment, the second through-hole 12 is in communication with the inside of the gas induction member 22, which will be described later. 【0034】 The second housing 10b is a disc-shaped member that is detachably attached to the front end of the first housing 10a, and as shown in Figure 3, it is shaped to accommodate a journal bearing 34, a thrust bearing 35, and a rotating shaft 31, which will be described later. 【0035】 The second housing 10b is provided in a shape that allows it to close the front end of the first housing 10a. 【0036】 The third housing 10c is a disc-shaped member that is detachably attached to the front end of the second housing 10b, and is shaped to accommodate a thrust bearing 35 and a rotating shaft 31, which will be described later, as shown in Figure 3. 【0037】 The third housing 10c is provided in such a way that it can restrain the thrust bearing runner 311 and the thrust bearing 35, which will be described later, so that they do not detach forward. 【0038】 A circular hole 14 is formed in the center of the third housing 10c, having a diameter sufficient for the rotation shaft 31 to be inserted. 【0039】 As shown in Figure 2, the second housing 10b and the third housing 10c are provided with at least one first through-hole 11, which allows the gas drawn in from the compressed gas intake port 24 to flow into the motor housing space 13. 【0040】 In this embodiment, the first through-holes 11 are provided in multiple locations and are spaced apart at predetermined intervals along the circumferential direction of the rotation axis 31. 【0041】 The first through-hole 11 can be formed in various forms, such as a circular hole, a slit-shaped hole extending along the radial direction of the rotation axis 31, or a fan-shaped hole that becomes narrower as it approaches the rotation axis 31. 【0042】 The third housing 10c has at least one third through-hole 15 formed therein, which is provided so that the gas drawn in from the compressed gas intake port 24 flows into the thrust bearing 35. 【0043】 In this embodiment, the third through-hole 15 includes an annular hole 15 formed by the cooperation of a circular hole 14 formed in the third housing 10c and the front end of a rotating shaft 31, which will be described later and is positioned in the circular hole 14, as shown in Figure 3. 【0044】 The fourth housing 10d is a disc-shaped member as shown in Figure 1, and is a member that closes the rear end of the gas induction member 22, which will be described later. 【0045】 The compression unit 20 is a device that draws in external air and compresses it, and comprises an impeller 21 and a gas induction member 22. 【0046】 The impeller 21 is a main component of the centrifugal pump and is a tire equipped with multiple curved blades, mounted to enable high-speed rotation. 【0047】 The gas guide member 22 is a metal member positioned in front of the impeller 21, and is a member that guides the air that flows into the impeller 21 and is compressed, and the air that has been compressed by the impeller 21. 【0048】 The gas induction member 22 is provided to close the rear end of the first housing 10a. 【0049】 In this embodiment, the gas induction member 22 is provided in a scroll casing form, as shown in Figure 1, which has a flow path formed so that the air that has passed through the impeller 21 flows in a vortex-like manner. 【0050】 The impeller 21 compresses the air that flows in through the compressed gas intake port 24, which will be described later, and the air compressed by the impeller 21 is discharged to the outside through the compressed gas outlet port 25. 【0051】 The compressed gas intake port 24 is a component that draws in external air to be compressed, and is located at the front end of the housing 10, but in this embodiment it is detachably connected to the front end of the second housing 10b. 【0052】 The air drawn into the compressed gas inlet 24 is compressed as it moves along the compressed gas flow path 26, which is connected from the compressed gas inlet 24 to the compressed gas outlet 25. 【0053】 The motor 30 is an electric motor that generates rotational force and is a device for supplying high-speed rotational force to the impeller 21. The motor 30 includes a rotating shaft 31, a stator 32, a rotor 33, a journal bearing 34, and a thrust bearing 35. 【0054】 The rotating shaft 31 is a rod member extending along the first central axis C1, and its rear end is coupled to the impeller 21 so as not to rotate relative to it, in order to rotate the impeller 21. 【0055】 The rotating shaft 31 includes a hollow portion H that extends along the first central axis C1, which is the longitudinal direction of the rotating shaft 31. 【0056】 A thrust bearing runner 311 is provided at the front end of the rotating shaft 31, having a position and shape corresponding to the thrust bearing 35. 【0057】 In this embodiment, the thrust bearing runner 311 is a typical disc-shaped runner. 【0058】 A gas inlet hole 312 is formed at the front end of the rotating shaft 31, which is in communication with the hollow portion H of the rotating shaft 31. 【0059】 The gas inlet 312 is a hole that guides the air flowing into the compressed gas intake 24 to flow into the hollow section H. 【0060】 In this embodiment, the gas inlet 312 is located inside the circular hole 14 of the third housing 10c. 【0061】 A gas outlet hole 313 is formed at the rear end of the rotating shaft 31, which is in communication with the hollow portion H of the rotating shaft 31. 【0062】 The gas outlet hole 313 is a hole that guides the air flowing into the hollow portion H of the rotating shaft 31 so that it reaches the impeller 21. 【0063】 In this embodiment, a plurality of gas outlet holes 313 are provided and arranged at predetermined intervals along the circumferential direction of the rotation axis 31. 【0064】 In this embodiment, the gas outlet 313 is located between the stator 32 and the impeller 21 of the motor 30, as shown in Figure 1, and is positioned inside the gas guide member 22. 【0065】 The stator 32 is a stator on which the field coil is wound, and is mounted in a fixed state within the motor housing space 13. 【0066】 The rotor 33 is a rotor containing permanent magnets and is coupled to the middle section of the rotating shaft 31. 【0067】 The journal bearings 34 are journal foil air bearings that rotatably support the rotating shaft 31 in order to reduce the frictional force generated by high-speed rotation, and are provided at the front and rear ends of the rotating shaft 31, respectively. 【0068】 Of the journal bearings 34, the journal bearing 34 located at the front end of the rotating shaft 31 is positioned behind the thrust bearing 35. 【0069】 The thrust bearing 35 is a thrust foil air bearing, and a pair of them are provided, each positioned on both sides of the thrust bearing runner 311. 【0070】 In this embodiment, the thrust bearing 35 is located at the very front of the housing 10, as shown in Figure 1. 【0071】 A predetermined gap exists between the stator 32 and the rotor 33, between the rotating shaft 31 and the stator 32, between the rotating shaft 31 and the journal bearing 34, and between the thrust bearing 35 and the thrust bearing runner 311. 【0072】 In this embodiment, the motor 30 is positioned between the compressed gas inlet 24 and the impeller 21. 【0073】 The cooling air passage includes a first cooling air passage 41, a second cooling air passage 42, and a third cooling air passage 43, which are air passages formed to allow the cooling gas contained inside to flow. 【0074】 Here, the cooling gas is air, which is the gas to be compressed, drawn in from the compressed gas inlet 24 by the suction force of the impeller 51. 【0075】 As shown in Figure 2, the first cooling air passage 41 is a cooling air passage that starts from the compressed gas intake port 24, passes through the outer surface of the rotating shaft 31, and reaches the impeller 21. 【0076】 In this embodiment, as shown in Figure 2, the first cooling air passage 41 starts from the compressed gas intake port 24 and proceeds through the first through hole 11, the front end of the motor housing space 13, the space between the stator 32 and the outer circumferential surface of the rotating shaft 31, and the second through hole 12 to reach the impeller 21. 【0077】 Therefore, the first cooling air passage 41 can rapidly cool the stator 32 of the motor 30. 【0078】 In this embodiment, as shown in Figure 3, the first cooling air passage 41 is provided so as to be able to cool the thrust bearing 35 by passing through the space where the thrust bearing runner 311 is housed as it passes through the first through hole 11. 【0079】 As shown in Figure 2, the second cooling air passage 42 is a cooling air passage that starts from the compressed gas intake port 24, passes through the hollow section H of the rotating shaft 31, and reaches the impeller 21. 【0080】 In this embodiment, as shown in Figure 2, the second cooling air passage 42 starts from the compressed gas intake port 24 and proceeds through the gas inlet hole 312, the hollow portion H of the rotating shaft 31, and the gas outlet hole 313 to reach the impeller 21. 【0081】 Therefore, the second cooling air passage 42 can rapidly cool the rotor 33 of the motor 30. 【0082】 The third cooling air passage 43 is a cooling air passage that starts from the compressed gas intake port 24, passes through the thrust bearing 35, and reaches the impeller 21. 【0083】 In this embodiment, as shown in Figure 3, the third cooling air passage 43 starts from the compressed gas intake port 24 and proceeds sequentially through the thrust bearing 35, the journal bearing 34, the front end of the motor housing space 13, the space between the stator 32 and the outer circumferential surface of the rotating shaft 31, and the second through hole 12 to reach the impeller 21. 【0084】 Therefore, the third cooling air passage 43 can rapidly cool the thrust bearing 35 and the journal bearing 34. 【0085】 In this embodiment, the third cooling air passage 43 merges with the first cooling air passage 41 at the rear end of the motor housing space 13, as shown in Figure 3. 【0086】 As a result, the cooling air passages 41, 42, and 43 are located at the front end of the compressed gas passage 26, and the air to be compressed, which flows along the compressed gas passage 26 from upstream of the impeller 21 toward the impeller 21, functions as the cooling gas. 【0087】 The following describes an example of how the turbo compressor 100 with the above configuration operates. 【0088】 When the rotating shaft 31 of the motor 30 rotates, the impeller 21 rotates, and the air drawn in from the compressed gas intake port 24 by the suction force of the impeller 21 flows through the first cooling air passage 41, the second cooling air passage 42, and the third cooling air passage 43, thereby cooling the motor 30. 【0089】 The air used to cool the motor 30 in this manner flows into the gas induction member 22, is compressed by the impeller 21, and then discharged to the outside through the compressed gas outlet 25. 【0090】 In this case, the air flowing through the first cooling air passage 41, the second cooling air passage 42, and the third cooling air passage 43 flows in one direction from the compressed gas intake port 24 to the impeller 21 and does not recirculate back to the compressed gas intake port 24. 【0091】 As shown in Figure 2, the air flowing along the first cooling air passage 41 starts from the compressed gas intake port 24 and proceeds sequentially through the first through hole 11, the front end of the motor housing space 13, the space between the stator 32 and the outer surface of the rotating shaft 31, and the second through hole 12 to reach the impeller 21, thereby rapidly cooling the outer surfaces of the stator 32 and the rotating shaft 31. 【0092】 As shown in Figure 2, the air flowing along the second cooling air passage 42 starts from the compressed gas intake port 24 and proceeds sequentially through the gas inlet hole 312, the hollow section H of the rotating shaft 31, and the gas outlet hole 313 to reach the impeller 21, thereby rapidly cooling the rotor 33 and the hollow section H of the rotating shaft 31. 【0093】 As shown in Figure 3, the air flowing along the third cooling air passage 43 starts from the compressed gas intake 24 and proceeds sequentially through the thrust bearing 35, journal bearing 34, the front end of the motor housing space 13, the space between the stator 32 and the outer surface of the rotating shaft 31, and the second through hole 12 to reach the impeller 21, thereby rapidly cooling the thrust bearing 35 and journal bearing 34, etc. 【0094】 The turbo compressor 100 with the above configuration is a turbo compressor that compresses gas and supplies it to the outside, and includes a compression unit 20 having a compressed gas intake port 24 into which gas is drawn in; an impeller 21 that compresses the gas that flows in through the compressed gas intake port 24; a compressed gas outlet 25 through which the gas compressed by the impeller 21 is discharged to the outside; a compressed gas flow path 26 connected from the compressed gas intake port 24 to the compressed gas outlet 25; a motor 30 having a rotating shaft 31 with one end coupled to the impeller 21 for rotating the impeller 21; a housing 10 having a motor housing space 13 for housing the motor 30; and a cooling air passage provided to pass through the motor housing space 13 and formed to allow the cooling gas contained inside to flow. The compressed gas intake port 24 is located at the front end of the housing 10. The impeller 21 is located at the rear end of the housing 10, the motor 30 is located between the compressed gas intake 24 and the impeller 21, the rotating shaft 31 includes a hollow section H extending along its longitudinal direction, and the cooling air passage includes a first cooling air passage 41 that starts from the compressed gas intake 24 and reaches the impeller 21 via the outer circumferential surface of the rotating shaft 31; and a second cooling air passage 42 that starts from the compressed gas intake 24 and reaches the impeller 21 via the hollow section H of the rotating shaft 31. The gas drawn in from the compressed gas intake 24 by the suction force of the impeller 21 cools the motor 30 as it passes through the first cooling air passage 41 and the second cooling air passage 42, thus providing the advantage that the stator 32 and rotor 33 of the motor 30 can be rapidly cooled using the relatively low-temperature cooling gas drawn in from the compressed gas intake 24. 【0095】 Furthermore, the turbo compressor 100 has the advantage of superior compression efficiency of the impeller 21, as the first cooling air passage 41 and the second cooling air passage 42 are formed so that the cooling gas flows in one direction from the compressed gas intake port 24 to the impeller 21 and does not recirculate. This is because, unlike conventional turbo compressors 1 which have a "vortex flow" in which the air used for cooling is heated and then flows back into the upstream side of the impeller for recompression. 【0096】 Furthermore, the turbo compressor 100 has the advantage that the stator 32 of the motor 30 can be rapidly cooled using a relatively low-temperature cooling gas, since the first cooling air passage 41 is formed to cool the stator 32 of the motor 30. Here, the amount of air flowing through the first cooling air passage 41 can be easily adjusted by adjusting the size and number of the first through holes 11 and the second through holes 12. 【0097】 Furthermore, the turbo compressor 100 has the advantage that the rotor 33 can be rapidly cooled using a relatively low-temperature cooling gas, since the second cooling air passage 42 is formed to cool the rotor 33 of the motor 30. Here, the amount of air flowing through the second cooling air passage 42 can be easily adjusted by adjusting the size and number of the gas inlet hole 312, the hollow section H, and the gas outlet hole 313. 【0098】 Furthermore, the turbo compressor 100 has the advantage of easily forming a first cooling air passage 41 so that the cooling gas flows along the longitudinal direction of the rotating shaft 31. This is because the front end of the housing 10 has at least one first through-hole 11 provided so that the gas drawn in from the compressed gas intake port 24 flows into the motor housing space 13, and the rear end of the housing 10 has at least one second through-hole 12 provided so that the gas housed in the motor housing space 13 flows into the impeller 21. 【0099】 Furthermore, the turbo compressor 100 has the advantage that, since at least one of the first through-holes 11 and the second through-holes 12 is arranged in multiple locations spaced apart at predetermined intervals along the circumferential direction of the rotating shaft 31, the flow rate and streamline shape of the air flowing along the first cooling air passage 41 can be easily adjusted. 【0100】 Furthermore, the turbo compressor 100 includes a thrust bearing 35 located at the front end of the rotating shaft 31 and a third cooling air passage 43 that starts from the compressed gas intake 24, passes through the thrust bearing 35, and reaches the impeller 21. This has the advantage of allowing the thrust bearing 35 to be rapidly cooled using a relatively low-temperature cooling gas. 【0101】 Furthermore, the turbo compressor 100 has the advantage that the flow rate and streamline shape of the air flowing along the third cooling air passage 43 can be easily adjusted, as at least one third through-hole 15 is formed at the front end of the housing 10, allowing the compressed gas drawn in from the compressed gas intake port 24 to flow into the thrust bearing 35. 【0102】 Furthermore, the turbo compressor 100 has the advantage that the third through-hole 15 can be easily formed without complex machining, since the third through-hole 15 includes an annular hole 15 formed by the cooperation of a circular hole 14 formed at the front end of the housing 10 and the front end of a rotating shaft 31 positioned in the circular hole 14. 【0103】 Furthermore, the turbo compressor 100 includes a rotating shaft 31 which is in communication with the hollow portion H of the rotating shaft 31 and includes a gas inlet 312 formed at the front end of the rotating shaft 31; and a gas outlet 313 which is in communication with the hollow portion H of the rotating shaft 31 and formed at the rear end of the rotating shaft 31. Since the gas outlet 313 is located between the stator 32 of the motor 30 and the impeller 21, the air flowing along the second cooling air passage 42 can reach the impeller 21 immediately without being mixed with the air flowing along the other cooling air passages 41 and 43. This makes it very easy to individually adjust the flow rate of the air flowing along the second cooling air passage 42. 【0104】 In this embodiment, there are no separate cooling fins inside the cooling air passage, but it goes without saying that separate cooling fins can be provided inside the cooling air passage. In this case, the cooling fins may be integrally formed with the housing 10, or they may be processed as separate components and then joined by methods such as press-fitting. 【0105】 In this embodiment, bearings 34 and 35 are provided in foil pneumatic bearings, but it goes without saying that other pneumatic bearings or various other types of bearings may be used. 【0106】 Although other sealing means for airtightness are not described in this embodiment, it goes without saying that a variety of sealing means can be used. 【0107】 Although the present invention has been described above, it goes without saying that the technical scope of the present invention is not limited to the embodiments described above, and equivalent configurations modified or altered by persons with ordinary skill in the art will not fall outside the scope of the technical idea of ​​the present invention.

Claims

[Claim 1] A turbo compressor capable of compressing a gas and supplying it to the outside, A compressed gas intake port for drawing in gas, An impeller for compressing the gas introduced from the aforementioned compressed gas inlet, A compressed gas outlet for discharging the gas compressed by the impeller to the outside, A compression unit comprising a compressed gas flow path connected from the compressed gas inlet to the compressed gas outlet, A motor having a rotating shaft at one end connected to the impeller is used to rotate the impeller. A housing having a motor housing space for housing the motor, It includes a cooling air passage provided to pass through the motor housing space and formed to allow the cooling gas contained inside to flow, The compressed gas intake is located at the front end of the housing, and the impeller is located at the rear end of the housing. The motor is positioned between the compressed gas inlet and the impeller. The aforementioned rotating shaft has a hollow portion extending along its longitudinal direction. The aforementioned cooling air passage is A first cooling air passage starting from the compressed gas intake, passing through the outer surface of the rotating shaft, and reaching the impeller, It includes a second cooling air passage that starts from the compressed gas intake port, passes through the hollow portion of the rotating shaft, and reaches the impeller, The gas drawn in from the compressed gas intake port by the suction force of the impeller passes through the first cooling air passage and the second cooling air passage to cool the motor. The turbo compressor further includes a thrust bearing located at the front end of the rotating shaft, The cooling air passage further includes a third cooling air passage that starts from the compressed gas intake, passes through the thrust bearing, and reaches the impeller. At least one third through-hole is formed at the front end of the housing, which is provided to allow the gas drawn in from the compressed gas intake to flow into the thrust bearing. The third through hole is, A turbo compressor characterized by including an annular hole formed by the cooperation of a circular hole formed at the front end of the housing and the front end of the rotating shaft positioned in the circular hole. [Claim 2] The turbo compressor according to claim 1, characterized in that the first cooling air passage and the second cooling air passage are formed so that the cooling gas flows in one direction from the compressed gas intake to the impeller. [Claim 3] The turbo compressor according to claim 1, characterized in that the first cooling air passage is formed to cool the stator of the motor. [Claim 4] The turbo compressor according to claim 1, characterized in that the second cooling air passage is formed to cool the rotor of the motor. [Claim 5] At least one first through-hole is formed at the front end of the housing, which is provided to allow the gas drawn in from the compressed gas intake to flow into the motor housing space. The turbo compressor according to claim 1, characterized in that at least one second through-hole is formed at the rear end of the housing, which is provided to allow the gas contained in the motor housing space to flow into the impeller. [Claim 6] The turbo compressor according to claim 5, characterized in that at least one of the first through-hole and the second through-hole includes a plurality of through-holes arranged at predetermined intervals along the circumferential direction of the rotating shaft. [Claim 7] The aforementioned rotating shaft is A gas inlet hole is formed at the front end of the rotating shaft and is connected to the hollow portion of the rotating shaft. It includes a gas outlet hole that communicates with the hollow portion of the rotating shaft and is formed at the rear end of the rotating shaft, The turbo compressor according to claim 1, characterized in that the gas outlet is located between the stator of the motor and the impeller.

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