Rotary electric machine, and air compressor using rotary electric machine

Abstract

To efficiently cool a heated portion of a rotary electric machine using a cooling medium supplied from the outside.SOLUTION: In a rotary electric machine 1 comprising a rotary shaft 8, a rotor 10, bearings 16 and 21 for supporting the rotary shaft 8, a stator 26, and a housing 2 for accommodating these, a cylindrical bearing accommodation part 31 for accommodating the bearings 16 and 21 is integrally formed in an end bracket 30 for holding one end side of a cylindrical part 3 of the housing 2. In the end bracket 30, flow paths (42 and 43) for a cooling medium supplied from the outside are formed, and an axial flow path 43 extending in the axial direction is branched to form a first flow path 44 connected to a nozzle 50 that injects the cooling medium to an end surface of the rotor 10 and a second flow path 45 connected to a nozzle 55 that injects the cooling medium to the bearings 16 and 21.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a rotating electric machine and an air compressor using the same. [Background technology]

[0002] Rotating electric machines are required to rotate at high speeds, which is one way to improve power density and reduce costs. With rotating electric machines, there are concerns that the increased rotational speed will increase friction loss in the bearings that rotatably support the rotating shaft, and that the increased frequency will increase eddy current loss and hysteresis loss in the rotor. These losses cause localized heat generation, so it is important to cool these heat generating locations. To address this issue, a cooling medium is supplied from the outside and sprayed at high speed and without diffusion against the object to be cooled. Specifically, a cooling medium spray portion is placed near the object to be cooled, and a flow path for the cooling medium to the spray portion is configured.

[0003] Since the bearings that support the rotating shaft of a rotating electric machine and the rotor are both rotating parts, in order to efficiently cool them, it is necessary to devise a way to ensure that the cooling medium is directed to the object to be cooled without being blocked by the surrounding fluid layer that rotates together. For example, a rotating electric machine described in Patent Document 1 is known. The rotating electric machine of Patent Document 1 supplies lubricating oil to the rotating shaft and the bearings from a cooling medium flow path processed in the end bracket. As a result, the cooling medium flow path of the rotating shaft and the bearings can be configured with a single cooling medium circuit, so that the lubrication of the bearings and the cooling of the bearings and the rotor can be realized inexpensively and simply. However, since the two bearings are fixed so as to fit within the thickness of the end bracket when viewed in the direction of the rotation axis, the thickness of the end bracket becomes large. In addition, since a cooling medium flow path extending radially is provided within the thickened end bracket, if the piping and the injection part are arranged so that each part does not interfere with each other, the device becomes complicated.

[0004] Another known prior art document is Patent Document 2. In Patent Document 2, a flow path for supplying a cooling medium (oil) is provided on the outer periphery of the housing, and the cooling medium is supplied radially from the outer periphery of the rotating body of the rotating electric machine toward the rotor. In addition, the cooling medium is branched from the outer periphery of the housing and supplied to the bearings through end brackets. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Special Publication No. 2007-523308 [Patent Document 2] JP 2018-91301 A Summary of the Invention [Problem to be solved by the invention]

[0006] In the rotating electric machine of Patent Document 1, the cooling medium is supplied only to the bearings and the rotating shaft, and the cooling medium supplied to the rotating shaft is sealed by a sealing lip, so that the cooling effect on the rotor core, which is the main heat generating part of the rotor, and the field source of the rotor cannot be expected. The field source means the permanent magnet in the case of a permanent magnet motor, and the rotor conductor in the case of an induction motor or a wound field motor. This leads to deterioration of the performance of the rotating electric machine due to thermal expansion of the rotor, thermal demagnetization of the magnet, and increased resistivity of the rotor conductor. In the rotating electric machine of Patent Document 2, a flow path for injecting the cooling medium onto the outer circumferential surface of the rotor is machined, and both flow paths are provided by branching from one oil supply port. However, in the method of applying the cooling medium to the outer circumferential side of the rotor, there is a risk that the cooling medium will be repelled by the fluid layer that rotates with the rotation of the rotor, hindering efficient cooling. In addition, in order to reliably supply the cooling medium to the bearings and the rotor, it is necessary to place a branch part in the space of the cylindrical part of the housing, which complicates the structure.

[0007] The present invention has been made in view of the above background, and has an object to improve the cooling performance of a rotating electric machine by supplying a cooling medium from outside the rotating electric machine. Another object of the present invention is to realize a rotating electric machine with a reduced number of parts and an air compressor using a rotating electric machine, by forming a cooling medium flow using a through hole that penetrates the inside of an end bracket that forms the housing of the rotating electric machine, thereby improving the cooling structure. [Means for solving the problem]

[0008] In order to achieve the above object, a rotating electric machine includes a housing, a rotor including a rotor core fixed to the rotating shaft, bearings for rotatably supporting the rotating shaft on one side (front side) and the other side (rear side) of the rotor core, and a stator including a stator core and an armature winding, and the bearing is held in the housing. The housing is formed by a cylindrical portion and bracket portions provided on both sides of the cylindrical portion, and a bearing holder for holding an outer ring of the bearing is formed on the bracket portion. The bracket portion is formed with an introduction flow path for a cooling medium supplied from outside the housing, and an axial flow path formed in the bearing holder so as to be connected to the introduction flow path and extend in the axial direction of the rotating shaft. The axial flow path is formed with a first flow path for injecting the cooling medium in the axial direction from an end face of the bearing holder close to the rotor to an end face perpendicular to the rotation axis of the rotor, and a second flow path for injecting the cooling medium from the middle of the axial flow path to the bearing. The downstream end of the first flow path is connected to a first nozzle, and the cross-sectional area of ​​the injection opening of the first nozzle is formed to be smaller than the cross-sectional area of ​​the first flow path. A second nozzle was connected to the downstream end of the second flow passage, and the cross-sectional area of ​​the injection opening of the second nozzle was formed to be smaller than the cross-sectional area of ​​the second flow passage.

[0009] According to another feature of the present invention, the second nozzle has one or more injection openings, and the cross-sectional area of ​​the second flow passage is formed to be larger than the sum of the cross-sectional areas of the injection openings of the second nozzles. Also, the injection opening of the first nozzle is provided closer to the rotation axis than the center of the radial range occupied by the end face of the rotor core when viewed in the radial direction from the rotation axis. The first nozzle is provided on the longitudinal end face of the bearing holder, i.e., the end face close to the rotor, and the second nozzle is provided on the inner peripheral surface of the bearing holder.

[0010] According to another feature of the present invention, the shape of the injection opening of the first nozzle may be formed to be any one of a circle, an ellipse, and a rectangle. Also, the injection direction of the cooling medium from the injection opening of the first nozzle may be inclined at a predetermined angle toward the rotation direction (circumferential direction) of the rotor. By driving the air end using the above-mentioned rotating electric machine, a highly efficient air compressor can be realized. Effect of the Invention

[0011] According to the present invention, a cooling structure for improving the cooling performance of a rotating electric machine can be realized with a simple flow path configuration, and the manufacturing cost and maintainability of the rotating electric machine can be improved. In addition, since the cooling medium is sprayed at high speed onto the end face of the rotor, it is possible to reliably hit and cool the end face of the rotor without being repelled by the fluid layer that rotates with the rotation of the rotor. Furthermore, since the cooling medium can be supplied simultaneously to not only the end face of the rotor but also the bearing portion, effective cooling of the bearing and its surroundings can be achieved. Other problems, configurations, and effects will be made clear from the description of the embodiments below. [Brief description of the drawings]

[0012] [Figure 1] 1 is a perspective view showing the appearance of a rotating electric machine 1 according to an embodiment of the present invention. [Diagram 2] 1 is a front view of a rotating electric machine 1 according to an embodiment of the present invention. [Diagram 3] 2 is a longitudinal sectional view of the axial front half of the rotating electric machine 1. FIG. [Figure 4] 2 is a vertical cross-sectional view of the rear axial portion of the rotating electric machine 1. FIG. [Diagram 5] 4 is a partial enlarged view of a coolant flow path 40 of the rotating electric machine 1 shown in FIG. [Figure 6] 6 is a partially enlarged view of the vicinity of a bearing receiving portion 31 shown in FIG. 5. [Figure 7] 5 is a partial enlarged view of a coolant flow path 70 of the rotating electric machine 1 shown in FIG. [Figure 8] 4 is a comparative diagram of the flow channel cross sections of the first flow channel 44 and the second flow channel 45 in FIG. 3. [Figure 9]1 is a comparison diagram of the thickness of the fluid layer rotating around the rotor 10 and the bearing 21. FIG. [Figure 10] FIG. 6 is a cross-sectional view of a first flow path according to a second embodiment of the present invention. [Figure 11] FIG. 11 is a cross-sectional view of a first flow path according to a third embodiment of the present invention. [Figure 12] FIG. 11 is a perspective cross-sectional view showing an air compressor 200 according to a fourth embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] A rotating electric machine 1 according to an embodiment of the present invention will be described below with reference to the drawings. In the following drawings, the same parts are given the same reference numerals, and repeated description will be omitted. In this specification, the front-rear, left-right, and up-down directions will be described as directions shown in the drawings. The rotating electric machine 1 of this embodiment is suitable for use as a driving source for an air compressor, but the object to be driven (driven equipment) in the present invention is not particularly limited. Note that the direction of the rotation axis Ax of the rotor 10 may be simply referred to as the "axial direction", and the rotation direction θ may be referred to as the "circumferential direction". EXAMPLES

[0014] FIG. 1 is a perspective view of a rotating electric machine 1 according to the present invention, and FIG. 2 is a front view of the rotating electric machine 1 shown in FIG. 1. The rotating electric machine 1 is an interior magnet synchronous motor, and a rotor and a stator, which are not shown in the figure, are housed in a housing 2. The housing 2 is mainly composed of a cylindrical body section 3 having openings on the front and rear sides, a front end bracket 30 attached to the front opening of the body section 3, and a rear end bracket 60 attached to the rear opening of the body section 3. In this embodiment, the housing 2 is formed by dividing it into three members (body section 3, end bracket 30, end bracket 60). The end brackets 30 and 60 correspond to the "bracket section" of the present invention. It should be noted that the division form in which the housing 2 is formed is arbitrary.

[0015] A through hole 32 is formed in the front end bracket 30, and one end of the rotating shaft 8 to which the rotor 10 (described later in FIG. 3) is fixed projects to the outside of the housing 2. Two supply ports 41, 71 for supplying the cooling medium are formed in the housing 2. The supply port 41 for supplying the cooling medium is formed at one location (here, the upper side) on the outer circumferential surface of the end bracket 30 located on the front side as viewed in the direction of the rotation axis Ax. Also, a supply port 71 for supplying the cooling medium is formed at one location (here, the upper side) on the outer circumferential surface of the end bracket 60 located on the rear side as viewed in the direction of the rotation axis Ax. In this specification, as shown in FIG. 2, the radial direction of the rotor 10 is represented by r (+r is the outer circumferential side), the axial direction (rotation axis direction) of the rotating shaft 8 of the rotor 10 is represented by Ax, and the rotation direction of the rotor 10 is represented by θ.

[0016] FIG. 3 is a vertical cross-sectional view (corresponding to part II in FIG. 2) of the axial front half of the rotating electric machine 1. The front side of the rotating electric machine 1 is formed with a body part 3, the outer side of which is manufactured as a cylindrical integral structure, and an end bracket 30 that closes a front opening 3a of the body part 3, forming a housing 2. The end bracket 30 is formed with a through hole 32 for passing the rotating shaft 8 forward, and a cylindrical bearing accommodating part 31 is formed from the periphery of the through hole 32 toward the rotor 10 on the inside. The bearing accommodating part 31 is formed to hold the two bearings 16, 21, and corresponds to the "bearing holder" of the present invention. The bearing accommodating part 31 is manufactured integrally with the end bracket 30 using the same material. The bearing accommodating part 31 and the end bracket 30 may be formed as separate pieces rather than as an integral unit.

[0017] The rotor 10 is fixed to the rotating shaft 8, is substantially cylindrical, and includes a rotor core 11, permanent magnets 12, and a rotor end plate 13. The stator 26 includes a substantially cylindrical stator core 27 and an armature winding 28. The rotor core 11 and the stator core 27 are manufactured, for example, by laminating a plurality of thin electromagnetic steel sheets in the direction of the rotation axis Ax using a known method.

[0018] The stator 26 is fixed to the inner peripheral surface of the body 3, and the rotor 10 is rotatably supported in a bearing housing 31 of the end bracket 30 via bearings 16 and 21. The end bracket 30 is fixed to the body 3 so as to ensure that the rotor 10 and the stator 26 are concentric. The end bracket 30 and the body 3 may be fixed by any method, for example, by a bolt (not shown). In order to prevent the intrusion of foreign matter into the inside of the rotating electric machine 1 and the leakage of the cooling medium, an O-ring 6 is interposed on the contact surface between the end bracket 30 and the opening 3a of the body 3. The end brackets 30 and 60 (described later in FIG. 4) and the body 3 may be made of carbon steel, stainless steel, aluminum alloy, or the like, and the rotor end plates 13 and 14 (described later in FIG. 4) may be made of non-magnetic stainless steel, aluminum, copper alloy, or the like.

[0019] The rotor core 11 and the rotor end plate 14 are fixed to the rotating shaft 8 by press-fitting or shrink-fitting. Other methods for fixing the rotor core 11 include screwing, bonding, welding, etc. The permanent magnet 12 is fitted into the rotor core 11, and may be fixed by additional bonding or resin integral molding. The rotating shaft 8 functions as an output shaft for power transmission, and the rotor core 11 and the permanent magnet 12 function as a magnetic circuit of the rotor 10. The rotor end plate 13 functions as an adjustment part for the static balance and dynamic balance of the rotor 10 by locally reducing the mass by cutting, etc. The stator 26 is manufactured by winding the armature winding 28 around the stator core 27, and has the function of passing a controlled current and voltage through the armature winding 28 to generate a rotating magnetic field in the stator core 27 and provide rotational power to the rotor 10.

[0020] The outer rings of the bearings 16 and 21 are fitted into the bearing accommodating portion 31 by a clearance fit or a transition fit. In this embodiment, the bearings 16 and 21 are back-to-back double row combination angular contact ball bearings arranged in two rows in the direction of the rotation axis Ax. However, the type and number of bearings are arbitrary, and any single-row or multi-row rolling bearing or other bearing means can be applied. An outer ring spacer 55 and an inner ring spacer 7b are arranged between the two rows of the bearings 16 and 21. The outer ring spacer 55 fits into the bearing accommodating portion 31 and contacts the outer rings of the bearings 16 and 21 on both axial sides. The inner ring spacer 7b fits into the rotating shaft 8 and contacts the inner rings of the bearings 16 and 21 on both axial sides. Additionally, the outer ring of bearing 16 is pressed axially forward from the side closer to rotor 10 (rear side) by outer ring holder 35, and the inner ring of bearing 21 is pressed axially toward the side closer to rotor 10 (rear side) by inner ring holder 7a. In this way, rotating electric machine 1 is operated with bearings 16, 21 held in a state with a predetermined preload, thereby reducing friction loss, vibration, and noise and lengthening the fatigue life.

[0021] The end bracket 30 is formed with a cooling medium passage 40. The cooling medium passage 40 extends from a supply port 41 to a nozzle 50 and an outer ring spacer 55, and includes an inlet passage 42 extending in the radial direction, an axial passage 43 extending from an end of the inlet passage 42 close to the rotation axis Ax inside the bearing accommodating portion 31 toward the rotation axis Ax, and a second passage 45 branching downward midway from the axial passage 43. Here, the "axial direction" does not need to be completely parallel to the rotation axis Ax, but is allowed to be within a certain range, and a passage deviating from the parallel state may be acceptable. A nozzle 50 serving as a first injection portion of the cooling medium is provided at an end of the axial passage 43 close to the rotor 10. That is, the nozzle 50 is provided on an end face of the bearing holder in the longitudinal direction (the direction of the rotation axis Ax).

[0022] An outer ring spacer 55 serving as a second injection portion for the cooling medium is provided downstream of the second flow passage 45. Here, only one axial flow passage 43 is disposed in the upper portion of the substantially cylindrical bearing accommodation portion 31 as viewed in the circumferential direction. Its circumferential position is preferably near the intersection of the II section and the IV-IV section as viewed in the direction of the rotation axis Ax, as shown in FIG. 2. By disposing it in this way, the path from the supply port 41 formed at the upper end of the end bracket 30 to the axial flow passage 43, i.e., the introduction flow passage 42, can be disposed in the shortest distance in the radial direction centered on the central axis Ax.

[0023] A cooling medium (not shown) whose temperature has been adjusted is pumped from the outside of the rotating electric machine 1 to the supply port 41 at a predetermined pressure. A part of the cooling medium pumped through the supply port 41 reaches the nozzle 50 from the introduction flow passage 42 and the axial flow passage 43, is sprayed from the nozzle 50, and reaches an end surface of the rotor 10 perpendicular to the rotation axis 8, here the rotor end plate 13. The rest of the pumped cooling medium branches off from the axial flow passage 43 and reaches the outer ring spacer 55 which serves as a second spray section, and is sprayed from the outer ring spacer 55 to reach the bearings 16 and 21, thereby serving as a means for dissipating heat. In this way, the cooling medium (not shown) is mainly supplied from the outside of the housing 2 to two parts (the rotor 10 and the bearings 16 and 21). Thereafter, the cooling medium remaining on the radially inner side of the bearing accommodating portion 31 is guided vertically downward of the housing 2 by gravity and negative pressure from the suction pump 91 through the through hole 58 and the first through hole 46 of the outer ring spacer 55 provided between the bearings 16 and 21, and the second through hole 47 provided on the outer side of the rotating electric machine 1 in the axial direction relative to the first through hole 46, and is discharged to the outside of the housing 2 through the discharge ports 4 and 5 (see FIG. 4). In this embodiment, it is assumed that lubricating oil is used as the cooling medium, but cooling media other than oil, such as HFC with added lubricant, can also be used.

[0024] After cooling the predetermined portion, the cooling medium becomes hot and moves by gravity to the vicinity of the inner bottom surface of the body portion 3, and is sucked from the outlet 4 at a predetermined negative pressure. In order to configure this cooling medium circulation circuit, an external cooling medium circuit 90 is connected to the rotating electric machine 1. The external cooling medium circuit 90 sucks the cooling medium inside the rotating electric machine 1 from the outlets 4, 5 (see FIG. 4 described later) by a suction pump 91, and temporarily stores it in a tank 92 for the cooling medium. The cooling medium stored in the tank 92 is sucked out by a pump 95 at a predetermined pressure, and after removing impurities by a filter 93, it is sent to a heat exchanger 94. In the heat exchanger 94, the cooling medium is adjusted to a predetermined low temperature by heat exchange with the outside air, and then the cooling medium is supplied again to the supply ports 41, 71 (see FIG. 4 described later) through the piping. In this way, the cooling medium is supplied into the internal space of the rotating electric machine 1, and cools the predetermined cooling target portion.

[0025] FIG. 4 is a vertical cross-sectional view (a cross-section corresponding to part II in FIG. 2) of the rear half of the rotating electric machine 1. The rear half of the rotating electric machine 1 is basically preferably configured to be symmetrical to the front half, but it is also possible to change the shape and number of the bearings 66, the shape of the bearing accommodating portion 61, and the like. The rear opening 3b of the body portion 3 of the housing 2 is closed by the rear end bracket 60. Since the rotating shaft 8 does not penetrate the rear side of the rotating electric machine 1, the end bracket 60 is not formed with a through hole penetrating in the direction of the rotation axis Ax. A cylindrical bearing accommodating portion 61 protruding forward in the direction of the rotation axis Ax is formed in the vicinity of the rotating shaft on the inner side of the end bracket 60, and holds the bearing 66 inside. The bearing accommodating portion 61 corresponds to the "rear bearing holder" of the present invention. That is, in this embodiment, a bearing holder is provided on each of the front and rear sides of the rotor 10. Here, the number of bearings 66 held in the bearing accommodating portion 61 is one, and a cylindrical roller bearing is used. The length of the bearing accommodating portion 61 in the direction of the rotation axis Ax is shorter than the length of the bearing accommodating portion 31 shown in Fig. 3 because there is one bearing 66. The outer ring 69 of the bearing 66 is fitted into the bearing accommodating portion 61 by a clearance fit or a transition fit.

[0026] Similar to the front end bracket 30 (see FIG. 3), a cooling medium passage 70 is formed in the end bracket 60. The cooling medium passage 70 is formed to include an inlet passage 72 extending radially from a supply port 71, an axial passage 73 extending forward in the direction of the rotation axis Ax from an end of the inlet passage 72 close to the rotation axis Ax, and a second passage 75 branching off midway from the axial passage 73. The axial passage 73 is disposed at only one location, at the top as viewed in the circumferential direction, of the substantially cylindrical bearing accommodating portion 61. A nozzle 80 serving as a first ejection portion of the cooling medium is provided at an end of the axial passage 73 close to the rotor 10. An outer ring spacer 85 serving as a second ejection portion of the cooling medium is provided downstream of the second passage 75. The outer ring spacer 85 has a function of maintaining a predetermined distance between the wall surface of the end bracket 60 and the rear side of the outer ring of the bearing 66, and also has a function as a nozzle for ejecting the cooling medium in a predetermined direction. The front side of the outer ring 69 of the bearing 66 is held by the outer ring pusher 65 .

[0027] The cooling medium jetted forward from the nozzle 80 reaches the rotor end plate 14. After reaching the rotor end plate 14 and absorbing heat from it, the cooling medium falls near the inner bottom surface of the body 3 due to gravity. The cooling medium jetted from the outer ring spacer 85, which serves as the second jetting section, reaches the bearing 66, as will be described in detail later with reference to FIG. 7. A through hole 88 is formed on the underside of the outer ring spacer 85 on the rear side of the bearing 66, and the through hole 88 communicates with the through hole 76 formed in the bearing accommodating section 61, so that the excess cooling medium that absorbed heat from the bearing 66 falls to the inner bottom surface of the body 3. The supply of the cooling medium from outside the housing 2 in this way serves as a means for removing exhaust heat near the rotor 10 and the bearing 66. The cooling medium that has accumulated at the inner bottom of the housing 2 is sucked at a predetermined negative pressure by the suction pump 91 through the exhaust port 5 formed on the underside of the body 3, and is returned to the cooling medium tank 92 (see FIG. 3).

[0028] FIG. 5 is a partially enlarged view of the cooling medium passage 40 of the rotating electric machine 1 shown in FIG. 3. The cooling medium passage 40 is a passage extending from a supply port 41 (see FIG. 3) that opens on an end surface of the end bracket 30 facing the outside of the rotating electric machine 1 to the vicinity of the rotor 10 and to the bearings 16 and 21 to be cooled. The cooling medium pumped from the supply port 41 (see FIG. 3) toward the inside of the rotating electric machine 1 flows as indicated by F1. In this embodiment, the supply port 41 opens at the vertical end (upper end) of the radial end surface of the end bracket 30, but since the cooling medium is pumped, it may open anywhere on the radial end surface. The cooling medium passage 40 extends from the radial outside to the inside at the introduction passage 42 and is connected to the axial passage 43 at a connection point 43a, and the cooling medium flows as indicated by F2. It is preferable that the cross-sectional shape and cross-sectional area of ​​the introduction passage 42 and the axial passage 43 are the same. These two flow paths 42, 43 can be easily formed by drilling.

[0029] At a branch point 43b in the middle of the axial flow passage 43, a second flow passage 45 branches out, which flows downward like a flow F6. The axial flow passage 43 downstream of the branch point 43b is connected to a nozzle 50 as a first flow passage of the flow F3. The nozzle 50 has a narrow opening at the tip, and by narrowing the cross section of the flow F3, the cooling medium is sprayed to the rotor end plate 13 as a high-speed flow F4. Meanwhile, the cooling medium flow F6 to the second flow passage 45 downstream of the branch point 43b flows from an outer ring spacer 55, which also functions as a nozzle, as a flow F7 to reach the first bearing 16, and then flows as a flow F8 to reach the second bearing 21.

[0030] In this embodiment, the bearing accommodating portion 31 is formed in the end bracket 30, and an axial flow passage 43 is provided to supply the cooling medium into the bearing accommodating portion 31. Furthermore, since the axial flow passage 43 is branched into a first flow passage 44 and a second flow passage 45 at a branch point 43b, it is possible to supply the cooling medium to a plurality of cooling targets by one flow passage (axial flow passage 43). Moreover, since the axial flow passage 43 is formed in the bearing accommodating portion 31, it is not necessary to arrange another pipe outside the bearing accommodating portion 31. The position of the flow passage (introduction flow passage 42) for supplying the cooling medium from the rotating electric machine 1 to the axial flow passage 43 is arbitrary. In this embodiment, the introduction flow passage 42 is formed in the radial direction because it can be formed by drilling from the radial outside to the inside of the end bracket 30, but it is also possible to arrange the introduction flow passage 42 as a separate pipe. For example, it may be connected to the outer surface (near the arrow 30a) of the end bracket 30 that is the shortest distance from the axial end face (connection point 43a) on the outer side of the rotating electric machine 1.

[0031] The first bearing 16 may be an angular ball bearing having a number of rolling elements 17 such as balls between the outer ring 18 and the inner ring 19. The second bearing 21 may be an angular ball bearing having a number of rolling elements 22 such as balls between the outer ring 23 and the inner ring 24. Here, the outer ring 18 and the outer ring 23 are arranged so that the arrangement and direction of the contact angle are opposite to each other. An outer ring spacer 55 provided between the outer ring 18 of the first bearing 16 and the outer ring 23 of the second bearing 21 not only functions to keep the distance between the outer rings 18 and 23 constant, but also functions as a second injection part (nozzle) of the cooling medium indicated by the arrow F6 passing through the second flow path. A cylindrical inner ring spacer 7b is provided between the inner ring 19 of the first bearing 16 and the inner ring 24 of the second bearing 21. The front side of the inner ring 24 of the second bearing 21 is restricted from moving forward in the axial direction by a cylindrical inner ring retainer 7a.

[0032] In this embodiment, the target position of the injection from the first injection part 50 is the position where the rotor 10 first collides with the extension of the first flow passage by the axial flow passage 43, that is, the side surface of the rotor 10 where the rotor end plate 13 is located. When the rotor end plate 13 has a smaller diameter than the rotor core 11, or when the rotor end plate 13 is not provided, the rotor core 11 or the permanent magnet 12 may be the target position of the injection. The target position of the second injection part 55 is the inner ring 19 or the rolling element 17 of the bearing 16, and further the inner ring 24 or the rolling element 22 of the bearing 21. However, the target position of the second injection part 55 may be the outer rings 18 and 23.

[0033] The first injection unit 50 is set to have an axial flow velocity component, and as shown by the arrow F4, the cooling medium is injected in a direction substantially parallel to the rotation axis Ax of the rotor 10, and falls on a vertical surface (rotor end plate 13). After that, as shown by the arrow F5, the cooling medium mainly flows radially outward while rotating in the circumferential direction due to the centrifugal force of the rotating rotor 10. The target position of the injection indicated by the arrow F4 of the first injection unit 50 is a radius Ro from the rotation axis Ax. The distance from the central axis (rotation axis) Ax of the rotating shaft 8 is a point that is larger than the outer radius Rs of the rotating shaft 8 at the axial position where it fits with the rotor core 11 and smaller than the outer radius Rr of the rotor core 11, and is smaller than the position of approximately the center (=(Rs+Rr) / 2) of the radial range occupied by the front end face of the rotor core 11. In this way, the target position of the injection indicated by the arrow F4 is set in an inner region closer to the rotating shaft 8 than near the center of the rotor core.

[0034] The cooling medium attached to rotor end plate 13 removes heat from rotor core 11 and permanent magnets 12, which are the main heat sources of rotor 10, via rotor end plate 13. After reaching the outer circumferential surface of rotor end plate 14 as indicated by arrow F4, the cooling medium is dispersed in the radial direction as indicated by arrow F5 while rotating due to centrifugal force, and falls on the axial end of armature winding 28, where it cools the heat generated by energization of coil 28. The cooling medium is then guided vertically downward in housing 2 by gravity and negative pressure from suction pump 91, and is discharged to the outside of housing 2 from discharge port 4 (see FIG. 3) and discharge port 5 (see FIG. 4).

[0035] A portion of the cooling medium injected from the outer ring spacer 55, which is the second injection portion, falls on the bearing 16 and is stirred in the circumferential direction by the rotation of the rolling elements 17 and the inner ring 19, forming a lubricating film between the rolling elements 17 and the inner ring 19 and the outer ring 18 over the entire bearing 16, thereby providing lubrication. Similarly, the rest of the cooling medium injected from the outer ring spacer 55 falls on the bearing 21 and is stirred in the circumferential direction by the rotation of the rolling elements 22 and the inner ring 24, forming a lubricating film between the rolling elements 22 and the inner ring 24 and the outer ring 23 over the entire bearing 21, thereby providing lubrication. In this way, by continuously injecting the temperature-adjusted cooling medium through the cooling medium flow path 40, it is possible to cool the heat generated in the bearings 16, 21 due to mechanical loss.

[0036] FIG. 6 is a further enlarged view of the vicinity of the bearing accommodating portion 31 of the rotating electric machine 1 shown in FIG. 5. In FIG. 6, the illustration of the two bearings 16, 21 is omitted. The length of the introduction flow passage 42, that is, the length from the supply port 41 (see FIG. 3) to the connection point 43a is H. The length of the axial flow passage 43 extending from the connection point 43a in the direction of the axis Ax is L1. In addition, a flow passage of length L2 is added to the tip of the axial flow passage 43 by the nozzle 50. Therefore, the length from the connection point 43a to the opening 53a for injection is L (= L1 + L2). It is preferable that the length L1 is longer than the length L2. By configuring the relationship L1>L2, the nozzle 50 can be made small, and manufacturability and assembly can be improved.

[0037] The nozzle 50 is formed as a separate part from the end bracket 30, and is a cylindrical member having a large diameter portion 51 having the same diameter as the cross section of the axial flow path 43, a small diameter portion 53 having a small cross section, and a tapered portion 52 formed so as to narrow the portion from the large diameter portion 51 to the small diameter portion 53 in a funnel shape. Here, the shape of the opening 53a at the tip of the small diameter portion 53 is circular. A male thread 54 is formed on a part of the outer shape of the nozzle 50, and the nozzle 50 is connected by screwing it into the mounting hole 48 having the female thread of the bearing accommodating portion 31, and consideration is given to preventing the cooling medium from leaking by using a seal tape, a seal washer, or the like. The outer ring holder 35 is shaped so that a substantially annular portion 35a and a body portion 35b extending forward from the inner peripheral end of the annular portion are integrally manufactured. Although not shown in FIG. 6, when the nozzle 50 is screwed into the bearing accommodating portion 31, the outer race retainer 35 may also be screwed together with the nozzle 50 so that the outer race retainer 35 is also fixed.

[0038] The outer ring spacer 55, which is the second injection portion, is formed with a through hole 56 communicating with the second flow passage 45. The lower end face of the through hole 56 is closed, and a first injection hole 57a penetrating from the vicinity of the lower end face to the rear side and a second injection hole 57b penetrating to the front side are formed. The injection hole 57a injects the cooling medium obliquely downward as shown by the arrow F7, i.e., toward the inner ring 19 of the first bearing 16, and the injection hole 57b injects the cooling medium obliquely forward as shown by the arrow F7, i.e., toward the inner ring 24 of the second bearing 21. The cross-sectional size of the injection holes 57a and 57b is set sufficiently smaller than the cross-sectional size of the through hole 56, and it is preferable to set the total cross-sectional area of ​​the injection holes 57a and 57b to be smaller than the cross-sectional area of ​​the second flow passage 45.

[0039] FIG. 7 is a partial enlarged view of the coolant flow passage 70 of the rotating electric machine 1 shown in FIG. 4. The inlet flow passage 72 extends vertically from the supply port 71 (see FIG. 4) to the connection point 73a, and an axial flow passage 73 is formed extending forward from the connection point 73a in the direction of the axis Ax. A nozzle 80 is connected to the tip of the axial flow passage 73. A second flow passage 75 is formed branching downward from a branch point 73b in the middle of the axial flow passage 73. An outer ring spacer 85 serving as a second injection part for the coolant is provided downstream of the second flow passage 75. Here, only one axial flow passage 73 is arranged in the upper part of the substantially cylindrical bearing accommodating part 61 as viewed in the circumferential direction. The circumferential arrangement is preferably near the intersection point of the II cross section and the IV-IV cross section as viewed in the direction of the rotation axis Ax as shown in FIG. 2.

[0040] The nozzle 80 is formed as a separate part from the bearing accommodating portion 61, and is a cylindrical member having a large diameter portion 81 having the same diameter as the cross section of the axial flow passage 73, a small diameter portion 83 having a small cross section, and a tapered portion 82 formed so as to narrow the portion from the large diameter portion 81 to the small diameter portion 83 in a funnel shape. Here, the shape of the opening 83a of the small diameter portion 83 is circular. A male thread portion (not shown) is formed on a part of the outer shape of the nozzle 80, and is screwed into the mounting hole 76 of the bearing accommodating portion 61 having a female thread, and consideration is given to preventing the cooling medium from leaking by using a seal tape, a seal washer, or the like. Although not shown in FIG. 7, when the nozzle 80 is screwed into the bearing accommodating portion 31, the outer ring holder 65 may also be screwed together.

[0041] The outer ring retainer 65 is formed of a substantially annular portion 65a and a cylindrical portion 65b extending forward from the inner peripheral end portion. The outer ring spacer 85 forms a second nozzle and has a hole portion 86 connected to the second flow passage 75, with a thin and long through hole 87 connected from near the bottom surface of the hole portion 86. The diameter of the through hole 87 is formed to be sufficiently small compared to the cross-sectional size of the hole portion 86.

[0042] The cooling medium flowing into the introduction passage 72 from the supply port 71 (see FIG. 4) flows from the radial outside to the inside as indicated by F11, changes direction to flow into the axial passage 73 as indicated by F12 at the branch point 73b, and is sprayed from the nozzle 80 to the side surface of the rear rotor end plate 14 as indicated by flow F13 to F14. Since the second passage 75 indicated by F15 branches off from the branch point 73b of the introduction passage 72, the cooling medium that reaches the inside of the outer ring spacer 85, which is the second nozzle, is sprayed in the direction of the arrow F16 toward the outer ring 67 and the rolling elements 68 of the bearing 66. The cooling medium, which has absorbed heat from the vicinity of the bearing 66 to be cooled and has become hot, falls to the bottom due to gravity inside the housing 2 and is discharged from the discharge port 5 (see FIG. 4) to the outside of the rotating electric machine 1 under a predetermined negative pressure.

[0043] 8 is a comparative diagram of the flow path cross sections of the first flow path 44 and the second flow path 45. The flow path cross-sectional area Sr2 of the nozzle 50 which is the first injection part and the flow path cross-sectional area Sb2 of the nozzle 55 which is the second injection part are set smaller than the flow path cross-sectional area Sr1 of the first flow path 44 near the branch point 43b and the flow path cross-sectional area Sb1 of the second flow path 45, respectively. In addition, the flow path cross-sectional area Sb2 of the nozzle 55 of the second injection part is set to be smaller than the flow path cross-sectional area Sr2 of the nozzle 50 of the first injection part.

[0044] Next, the operation, effect, and principle of this embodiment will be described. The coolant flow path 40 is formed so that the coolant is pumped from a single supply port 41 machined in the end bracket 30 and branches at a branching portion 43b into a first flow path 44 that sprays the coolant to the rotor end plate 14 and a second flow path 45 that sprays the coolant to the bearings 16, 21. This makes it possible to supply the coolant to the rotor end plate 14 and the bearings 16, 21 without installing additional piping members inside the rotating electric machine 1, which simplifies the device, reduces costs, and makes it easy to disassemble and maintain.

[0045] The axial flow passage 43 connected to the introduction flow passage 42 forms a flow passage from the branch point 43b to the first injection part (nozzle 50) as a first flow passage 44. In other words, the first flow passage 44 refers to a part of the axial flow passage 43 downstream of the branch point 43b. By forming the first flow passage 44, the cooling medium can be easily routed to the vicinity of the rotor end plate 14, and the cooling medium can be applied to the end face of the rotor 10, so that the rotor 10 can be efficiently cooled without being blocked by the fluid layer that circulates around the rotor 10. Furthermore, since the flow passage by this axial flow passage 43 passes axially through the outer diameter side of the bearings 16 and 21 of the bearing receiving part 31, it also has the effect of cooling the heat transferred from the outer ring 18 of the bearing 16 and the outer ring 23 of the bearing 21 to the bearing receiving part 31 and the end bracket 30.

[0046] In this way, the cooling mechanism of this embodiment can reduce the temperature of the bearings 16, 21 to maintain the bearing clearance at an appropriate level, thereby reducing mechanical loss and improving fatigue life. In addition, a mechanism for injecting the cooling medium to the bearings 16, 21 is realized by forming the second flow passage 45 extending downward (radially) from the branch point 43b and using the outer ring spacer 55 of a simple structure attached thereto, without using a complicated piping configuration. This injection mechanism can be easily routed up to the vicinity of the bearings 16, 21. This makes it possible to minimize attenuation of the injection flow rate of the cooling medium and prevent diffusion, and ensures that the cooling medium hits the bearings 16, 21 without being blocked by the fluid layer circulating around them, thereby cooling them reliably.

[0047] The first injection portion 50 is provided in a direction having an axial flow velocity component, and is applied to a surface approximately perpendicular to the rotation axis Ax of the rotor 10. At this time, after the cooling medium is applied to the rotor 10, it spreads in the circumferential and radial directions due to frictional force and centrifugal force, and the cooling medium is adsorbed over a wide area. For example, when the cooling medium is injected radially inward onto the cylindrical surface of the rotating shaft 8, the cooling medium is dispersed only in the circumferential direction after it is applied to the rotor 10, so the area where the cooling medium is adsorbed is limited. As described above, this embodiment can improve the cooling performance.

[0048] The first injection unit 50 sprays the cooling medium onto the rotor end plate 14, which is provided in contact with the rotor core 11 and the permanent magnets 12 in the axial direction. In the rotor 10, the permanent magnets 12 generate heat due to eddy current loss, and at high temperatures, this leads to performance degradation of the rotating electric machine 1 due to thermal demagnetization. The rotor core 11 generates heat due to eddy current loss and hysteresis loss, and at high temperatures, this causes further increase in loss due to thermal stress, heat is transferred to the rotating shaft 8 and thermally expands in the axial direction, causing preload abnormalities in the bearings 16 and 21, and heat is transferred to the inner ring 19, causing an increase in mechanical loss due to a reduction in the operating clearance of the bearings 16 and 21, and a shortened fatigue life, resulting in performance degradation of the rotating electric machine 1. By spraying the cooling medium onto the rotor end plate 14, the rotor core 11 and the permanent magnets 12 can be cooled via the rotor end plate 14, and furthermore, since they are provided in contact with each other in the axial direction, they can be cooled efficiently, which results in preventing the above-mentioned performance degradation and improving the performance of the rotating electric machine 1. Furthermore, even if the rotor end plate 14 is not provided between the first injection portion 50 and the rotor core 11 (the same applies when the rotor end plate 14 has a smaller diameter than the extension of the center line of the first injection portion 50 or is not present), the cooling medium is applied directly to the rotor core 11 or the permanent magnet 12, so that the same or greater cooling effect can be obtained.

[0049] The flow passage cross-sectional area Sr2 of the first injection portion 50 and the flow passage cross-sectional area Sb2 of the second injection portion 55 are set smaller than the flow passage cross-sectional area Sr1 of the first flow passage near the branch point 43b and the flow passage cross-sectional area Sb1 of the second flow passage 45, respectively. This allows the cooling medium to be injected toward the bearings 16, 21 and the rotor 10 at high speed without being widely dispersed, and the cooling medium can be reliably applied to penetrate the surrounding fluid layer that rotates with the rotor, thereby cooling the bearings 16, 21 and the rotor 10.

[0050] The flow passage cross-sectional area Sb2 of the second injection part 55 is set to be smaller than the flow passage cross-sectional area Sr2 of the first injection part 50. FIG. 9 is a comparison diagram of the thickness of the fluid layer that rotates with the rotor 10 and the bearing 21. The bearing 21 rotates with the rolling elements 22 arranged at equal intervals in the circumferential direction. Therefore, the surrounding fluid is stirred by the rolling elements 22, and a high-speed rotating fluid layer with a thickness Wb equivalent to the thickness of the rolling elements 22 in the axial direction is formed. On the other hand, at the axial end face of the rotor end plate 14, only the fluid layer with a thickness Wr of the very surface layer rotates at high speed depending on the surface roughness and the viscosity of the surrounding fluid. Since Wb is much larger than Wr, the injection speed required to avoid being blocked by the fluid layer is higher for the bearing 21. At the target position of the cooling medium, the rotor 10 is located on the outer diameter side than the bearing 21, and even when the circumferential speed is high, the injection speed required for the bearing 21 is higher. Therefore, by setting the flow passage cross-sectional area Sb2 of the second injection part 55 to be smaller than the flow passage cross-sectional area Sr2 of the first injection part 50, the amount of cooling medium applied to the bearings 16 and 21 can be increased while the cooling medium is reliably applied to the rotor 10, thereby improving cooling performance. The first injection part 50 and the second injection part 55 are set to have a circular flow passage cross-sectional shape. This makes it possible to reduce the pressure loss in the cooling medium flow passage 40 and reduce the output of the pump 95, thereby configuring an inexpensive and small external cooling medium circuit 90.

[0051] The cooling structure of the rotating electric machine has been described above using the embodiment. The features described in FIG. 8 and FIG. 9 are also applicable to the rear cooling medium flow path 70 shown in FIG. 4 and FIG. 7. This embodiment assumes an interior permanent magnet synchronous motor, but the same effect can be obtained with the same configuration as in the present disclosure for other types of motors and generators. In the case of a surface permanent magnet synchronous motor, only the radial position and shape of the magnet are different, so the same effect can be obtained with the same principle. In the case of an induction motor and a wound field motor, the field source is not a permanent magnet but a rotor conductor, and during operation, a field current is passed through the rotor conductor, causing copper loss in accordance with Ohm's law and generating heat. When the temperature rises, the performance deteriorates due to a further increase in copper loss caused by an increase in the resistivity of the rotor conductor, so the performance deterioration can be prevented by applying the same configuration. For a synchronous reluctance motor, switched reluctance motor, etc. that does not have a field source in the rotor and has only a rotating shaft and rotor core as a minimum configuration, the performance deterioration occurs due to the heat generation of the rotor core as described above, so the same effect can be obtained with the same cooling configuration. As described above, the same effects can be obtained with this configuration for any rotating electrical machine such as a motor or generator that has a heat generating factor in the rotor. EXAMPLES

[0052] FIG. 10 shows a second embodiment in which the shape of the first injection part is changed, and corresponds to the IV-IV plane of FIG. 2. In this embodiment, the shape of the nozzle 50A is partially different from that of the nozzle 50 of the first embodiment. In the nozzle 50A shown in Shape 1, the shape of the opening 53b is substantially rectangular, and for example, the side extending in the horizontal direction is made to be the long side. The shape of the opening 53b can suppress the diffusion of the cooling medium after injection in only one direction, and the adsorption area of ​​the cooling medium can be increased without significantly decreasing the injection speed, compared to the case where the area is increased with a circular or regular square shape. In addition to the effects of the first embodiment, the cooling performance of the rotating electric machine 1 can be further improved.

[0053] Shape 2 in Fig. 10 is a modified example of the second embodiment. Here, opening 53c is not rectangular, but elliptical with the major axis extending horizontally. In this way, the degree of diffusion of the cooling medium after injection can be increased in one specific direction while decreasing the degree of diffusion in another direction. The flow path shapes of openings 53b and 53c in the narrow diameter portion are the same, and it is preferable to determine the shape of tapered portion 52 so that the portion from wide diameter portion 51 to the narrow diameter portion is connected by a smooth curved surface. EXAMPLES

[0054] FIG. 11 shows a third embodiment in which the shape of the first flow passage is changed, and corresponds to the cross section taken along the line IV-IV in FIG. 2. In this embodiment, only the nozzle 50C is different from the first embodiment. The configuration other than the nozzle 50C is the same as that of the first embodiment. The nozzle 50C has a large diameter portion 51 that does not penetrate in the axial direction, and a thin through hole 53d is formed near the tip end surface 52d, which is inclined at a predetermined angle toward the rotation direction of the rotor 10. Therefore, when the cooling medium sprayed from the nozzle 50C is adsorbed on the rotor end plate 13, the difference in peripheral speed between the rotor end plate 13 and the cooling medium can be reduced, so that the brake torque due to friction of the cooling medium can be reduced, and the performance of the rotating electric machine 1 can be improved. EXAMPLES

[0055] FIG. 12 is a partially sectional perspective view showing the appearance of an air compressor 200 according to a fourth embodiment of the present invention. The air compressor 200 has an air end 100 driven by the rotating electric machine 1 shown in the first embodiment. The configuration described below is an example of a screw-type air compressor, but the rotating electric machine 1 of the present invention can be applied to various types of air compressors. As shown in FIG. 12, the air compressor 200 includes a rotating electric machine 1 (see FIGS. 1 to 9) that supplies rotational power, and an air end 100 that uses the rotational force of the rotating electric machine 1 to generate compressed air. The M rotor 120 of the air end 100 is connected to the rotating shaft 8 of the rotating electric machine 1 by a connecting means (e.g., a spline, a coupling, a gear, etc.) and supplies the rotational power of the rotating electric machine 1 to a first shaft 108 of the air end 100. A first bevel gear 110 is provided at the tip of the first shaft 108, and the bevel gear 110 is screwed with the adjacent second bevel gear 130 to rotate the second bevel gear 130 in the opposite direction at the same speed as the first bevel gear 110. Since the second bevel gear 130 is provided at the tip of the second shaft 138, the F rotor 140 fixed to the second shaft 138 by the rotation of the second bevel gear 130 rotates at the same speed in the opposite direction to the M rotor 120 fixed to the first shaft 108.

[0056] Air is sucked in through the suction port of the M rotor 120 (not shown in the figure), and as the M rotor 120 and the F rotor 140 rotate, the teeth of each rotor disengage, and the air is sucked in to fill the tooth space. When the M rotor 120 and the F rotor 140 rotate further and the air is blocked by the wall of the casing 102, the suction is completed. The air trapped between the tooth space and the casing is compressed by the meshing of the rotors 120, 140. As the rotors 120, 140 rotate, the air moves in the axial direction and is further compressed between the tooth space 145 and the casing 102, and reaches a predetermined pressure at the discharge port (not shown in the figure). The compressed air is discharged from the discharge port on the discharge side opened in the casing 102.

[0057] As described above, according to this embodiment, the air compressor 200 includes the rotating electric machine 1 according to any one of the first to third embodiments, thereby improving the life and efficiency of the rotating electric machine 1 and improving the life and efficiency of the air compressor.

[0058] Although the present invention has been described above based on the embodiments, the present invention is not limited to the above-mentioned embodiments, and various modifications are possible within the scope of the gist of the present invention. Moreover, the above-mentioned embodiments are not necessarily limited to those having all the configurations described. Furthermore, it is possible to add, delete, or replace some of the configurations of the embodiments with other configurations. For example, the same effects can be obtained with any type of rotating electric machine having a heat generating element in the rotor 10 other than an interior magnet synchronous motor. [Explanation of symbols]

[0059] 1 Rotating Electric Machine 2. Housing 3. Cylindrical section 3a, 3b opening 4, 5 outlet 6 O-ring 7a Inner ring holder 7b Inner ring spacer 8 Rotation Axis 10 Rotor 11 Rotor core 12 Permanent magnets 13, 14 Rotor end plate 16 (First) Bearing 17 Rolling elements 18 Outer ring 19 Inner Circle 21 (Second) Bearing 22 Rolling elements 23 Outer Ring 24 Inner Circle 26 Stator 27 Stator Core 28 Armature Winding 30 End bracket 31 Bearing housing 32 Through hole 35 Outer ring holder 40 Coolant flow passage 41 Supply port 42 Inlet Channel 43 Axial flow passage 43a Connection point 43b Junction 43c opening 44 First Stream 45 Second Channel 46, 47 Through holes 48 Mounting holes 50, 50A to 50C Nozzle (first injection part) 51 Large diameter part 52 Tapered section 53 Thin section 53a, 53b, 53c opening 53d through hole 54 Male thread 55 Outer ring spacer (second nozzle) 56 Through hole 57a (First) Jet 57b (Second) jet nozzle 58 Through hole 60 End bracket 61 Bearing housing 65 Outer ring holder 66 Bearings 67 Inner Circle 68 Rolling elements 69 Outer Ring 70 Coolant flow passage 71 Supply Inlet 72 Inlet Channel 73 Axial flow passage 73a Connection 73b Branch 73c Opening screw part 75 Second Channel 76 Mounting hole 80 Nozzles 81 Large diameter part 82 Tapered section 83 Thin section 83a aperture 85 Outer ring spacer (nozzle) 86 Hole 87, 88 Through holes 90 External coolant circuit 91 Suction Pump 92 Tank 93 Filters 94 Heat exchanger 95 Pump 100 Airend 102 Casing 108 1st Shaft 110 1st bevel gear 120M rotor 130 2nd bevel gear 138 Second Shaft 140 F rotor 145 Tooth Space 200 Air Compressor Ax axis of rotation F1~F8, F11~F13 Coolant flow Rs Shaft outer radius Rr Rotor core outer radius Ro Radius of target position Sr1 Cross-sectional area of ​​the first channel just after the branch Sr2 Cross-sectional area of ​​the first jet Sb1: Cross-sectional area of ​​the second channel just after the branch Sb2: Cross-sectional area of ​​the second jet Wb Thickness of the rotating fluid layer in the bearing Wr Rotating fluid layer thickness of rotor

Claims

1. A rotating electric machine including a housing, a rotor including a rotating shaft, a rotor core fixed to the rotating shaft, bearings supporting the rotating shaft on one side and the other side of the rotor core so as to be freely rotatable, and a stator including a stator core and an armature winding, the bearings being held by the housing, The housing is formed by a cylindrical portion and bracket portions provided on both sides of the cylindrical portion, a bearing holder for holding an outer ring of the bearing is formed in the bracket portion, The bracket portion is provided with an inlet passage for a cooling medium supplied from outside the housing, and an axial flow passage formed in the bearing holder so as to be connected to the inlet passage and extend in the axial direction of the rotating shaft, A rotating electric machine characterized in that the axial flow path has a first flow path that sprays the cooling medium axially from the bearing holder to an end face of the rotor perpendicular to the rotation axis, and a second flow path that branches off from the middle of the axial flow path to spray the cooling medium to the bearing.

2. 2. The rotating electric machine according to claim 1, The first flow path is connected to a first nozzle, and a cross-sectional area of ​​an injection opening of the first nozzle is formed smaller than a cross-sectional area of ​​the first flow path, A rotating electric machine, characterized in that the second flow passage is connected to a second nozzle, and a cross-sectional area of ​​an injection opening of the second nozzle is formed smaller than a cross-sectional area of ​​the second flow passage.

3. 3. The rotating electric machine according to claim 2, The second nozzle has a plurality of injection openings, A rotating electric machine, characterized in that a cross-sectional area of ​​the second flow passage is formed to be larger than a total cross-sectional area of ​​the injection openings of a plurality of the second nozzles.

4. 4. The rotating electric machine according to claim 3, A rotating electric machine characterized in that the injection opening of the first nozzle is provided closer to the rotating shaft than the center of the radial range occupied by the end face of the rotor core when viewed radially from the rotating shaft.

5. 4. The rotating electric machine according to claim 3, The bearing holder is cylindrical, the first nozzle is provided on an end surface of the bearing holder in a longitudinal direction, The rotating electric machine according to claim 1, wherein the second nozzle is provided on an inner circumferential surface of the bearing holder.

6. 6. The rotating electric machine according to claim 5, 2. A rotating electric machine, wherein the shape of the injection opening of the first nozzle is any one of a circle, an ellipse, and a rectangle.

7. 6. The rotating electric machine according to claim 5, a direction in which the cooling medium is sprayed from the spray opening of the first nozzle is inclined at a predetermined angle to a rotation direction of the rotor,

8. The rotating electric machine according to any one of claims 1 to 7, and an air end driven by the rotating electric machine.

9. A rotor having a permanent magnet and a rotating shaft fixed to the rotating shaft is disposed in the housing. a bearing for rotatably supporting the rotating shaft at the front and rear sides of the rotor; A rotating electric machine including a stator including a stator core and an armature winding, the housing is formed to include a cylindrical body portion, a front end bracket that closes a front side of the body portion and has a through hole through which the rotating shaft passes, and a rear end bracket that closes a rear side of the body portion, a front bearing holder for holding an outer ring of a front bearing that supports a front side of the rotating shaft is formed on the inside of the front end bracket, a front end bracket is provided with a front inlet passage for supplying a cooling medium from an outside, and a front axial passage connected to the front inlet passage and extending in the axial direction of the rotating shaft; The front axial flow passage has a narrowed opening at a tip thereof, so that the cooling medium is sprayed to the front side surface of the rotor at an increased speed, a front bearing holder for holding an outer ring of a rear bearing that supports a rear side of the rotating shaft is formed on the inner side of the rear end bracket, a front inlet passage for supplying a cooling medium from an outside and a rear axial passage connected to the front inlet passage and extending in the axial direction of the rotating shaft are formed in the rear end bracket; A rotating electric machine characterized in that the rear axial flow passage of the rear end bracket has a narrowed opening at its tip, thereby increasing the speed of the cooling medium and injecting it onto the rear side of the rotor.

10. 10. The rotating electric machine according to claim 9, the front axial flow passage is formed so as to branch into a second front flow passage in a direction intersecting the rotation axis and supplying a cooling medium to the bearing, a second rear flow passage formed in the rear axial flow passage so as to branch off in a direction intersecting the rotation axis and supplying a cooling medium to the bearings;

11. 11. The rotating electric machine according to claim 10, a second front nozzle having a narrowed tip opening is provided at an opening portion of the second front flow passage, a second rear nozzle having a narrowed opening at a tip end thereof is provided at an opening portion of the second rear flow passage, said second rear nozzle being characterized in that

12. 12. The rotating electric machine according to claim 11, A rotating electric machine characterized in that two bearings are provided on the front end bracket at a distance in the axial direction, and an opening portion of the second front nozzle is located between the two bearings.

13. The rotating electric machine according to any one of claims 9 to 12, and an air end driven by the rotating electric machine.

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