Fluid machinery

Abstract

To provide a fluid machine which enables a motor cooling mechanism to be used as an inverter cooling mechanism.SOLUTION: A centrifugal blower 1 includes: a motor part 41 having a motor 10, which rotates a rotary shaft 8 of an impeller 2, and a motor housing 5; an inverter part 51 having an inverter unit 52, which drives the motor part 41, and an inverter housing 53; and a cooling fan 34 which is provided at the rotary shaft 8 and circulates cooling air into the inverter housing 53 and the motor housing 5. The inverter housing 53 has: a cylindrical side wall 54; a suction port 58 which is provided on the side wall 54 and suctions the cooling air; and a lid part 55 which is attached to the side wall 54 so as to close an end part of the side wall 54. The inverter unit 52 faces the suction port 58 in a rotation diameter direction, is fixed to the lid part 55, and may be removed with the lid part 55 from the side wall 54.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a fluid machine.

Background Art

[0002] In fluid machines such as blowers and compressors, a motor may be used as a drive source for the impeller. In this case, during operation of the fluid machine, it is necessary to cool the motor that generates heat. For example, in the fluid machine of Patent Document 1, a cooling fan is provided on the rotating shaft of the impeller, and cooling air flows into the motor housing by this cooling fan. The rotor and stator, which are the main heat generation sources, are cooled by this cooling air.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In this type of fluid machine, it is also conceivable that there is an inverter that applies drive power to the motor. In this case, since the inverter can also become a heat generation source, it is similarly necessary to cool it. However, providing a cooling mechanism for the inverter in addition to the cooling mechanism for the motor as described above will hinder miniaturization of the entire device. For the purpose of miniaturizing the device, it is desired to make the cooling mechanisms for the motor and the inverter common. An object of the present invention is to provide a fluid machine in which the cooling mechanisms for the motor and the inverter are made common.

Means for Solving the Problems

[0005] The fluid machine of the present invention includes a motor unit having a motor that rotates the rotating shaft of the impeller and a motor housing that houses the motor, An inverter unit that supplies driving power to the motor unit, and an inverter housing that is connected to the motor housing and houses the inverter unit, an inverter section having the same; A cooling fan provided on the rotating shaft and configured to flow cooling air that sequentially passes through the inside of the inverter housing and the inside of the motor housing; The inverter housing has a cylindrical side wall that surrounds the rotation axis of the rotating shaft and extends in the direction of the rotation axis, an air intake port provided in the side wall for sucking the cooling air from the outside, and a lid portion attached to the side wall so as to close an end portion of the side wall. The inverter unit is disposed at a position facing the air intake port in the radial direction of rotation and is fixed to the lid portion, and is removable from the side wall together with the lid portion.

[0006] A heat sink facing the air intake port may be attached to the outer peripheral portion of the inverter unit. Further, the inverter housing may have an air filter provided at the air intake port.

[0007] The fluid machine of the present invention may be a fluid machine having a rotating shaft, a motor that rotates the rotating shaft, a motor housing that houses the motor, a motor section having the same, an inverter unit that supplies driving power to the motor section, an inverter housing that is connected to the motor housing and houses the inverter unit, and a cooling fan provided on the rotating shaft and configured to flow cooling air that sequentially passes through the inside of the inverter housing and the inside of the motor housing, wherein the inverter unit is arranged so as to be aligned in the axial direction of the rotating shaft with respect to the motor.

[0008] The inverter housing may have a cylindrical side wall that surrounds the rotation axis of the rotating shaft and extends in the direction of the rotation axis, and an air intake port provided in the side wall for sucking the cooling air from the outside, and the inverter unit may be disposed in a region where the rotation axis intersects inside the air intake port.

[0009] A heat sink facing the air inlet may be attached to the outer peripheral portion of the inverter unit. The inverter housing may have an air filter provided at the air inlet. The motor unit may have a gas bearing that pivotally supports the rotating shaft. A part of the rotating shaft may be arranged surrounded by the inverter unit.

[0010] The fluid machine of the present invention includes a rotating shaft, a motor that rotates the rotating shaft, an inverter unit that supplies driving power to the motor, a cooling fan that rotates together with the rotating shaft and generates a flow of cooling air, a motor housing that houses the motor and forms a motor cooling flow path through which the cooling air passes to cool the motor, a fan housing flow path that communicates with the motor cooling flow path, houses the cooling fan, and allows the cooling air to pass in the radial direction of rotation of the rotating shaft, and an inverter housing that communicates with the motor cooling flow path and forms an inverter cooling flow path through which the cooling air passes to cool the inverter unit. The fan housing flow path, the motor cooling flow path, and the inverter cooling flow path may be arranged axially along the rotating shaft, and it may be a fluid machine.

Advantages of the Invention

[0011] According to the present invention, it is possible to provide a fluid machine in which the cooling mechanisms of the motor and the inverter are made common.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

DETAILED DESCRIPTION OF THE INVENTION

[0013] Referring to FIG. 1, a fluid machine according to an embodiment of the present disclosure will be described. In FIG. 1, the left side with respect to the paper surface is the tip (first end) side, and the right side with respect to the paper surface is the base end (second end) side. In the following description, the terms "tip side" and "base end side" are used with reference to the axial direction.

[0014] In the present embodiment, as an example of a fluid machine, a centrifugal blower 1 will be described. The centrifugal blower 1 is, for example, an air-cooled electric blower that sucks in air and discharges it at a predetermined pressure. The centrifugal blower 1 is provided with an air suction port on the tip side. The centrifugal blower 1 (fluid machine) includes an impeller housing 3 in which an impeller 2 is housed, and a motor unit 41 as a drive source for rotating the impeller 2. The motor unit 41 includes a rotor 8a fixed to the rotation shaft 8 of the impeller 2, a coil 4 (stator) provided around the rotor 8a, and a motor housing 5 in which the coil 4 is housed. Further, the centrifugal blower 1 includes an inverter unit 51. The inverter unit 51 supplies driving power to the motor unit 41.

[0015] The motor housing 5 includes a cylindrical motor housing main body 6. Heat dissipation fins 7 are formed on the outer peripheral surface of the motor housing main body 6. The motor housing main body 6 includes a first end 5a on the tip side and a second end 5b on the base end side in the axial direction. The motor housing main body 6 is provided with an insertion hole 6a extending in the axial direction between the first end 5a and the second end 5b. A rotating shaft 8 made of, for example, stainless steel is inserted into the motor housing main body 6.

[0016] The rotating shaft 8 is supported by a first bearing portion 18 provided near the first end 5a within the motor housing main body 6 and a second bearing portion 11 provided near the second end 5b within the motor housing main body 6. The rotating shaft 8 is rotatable about its rotation axis X.

[0017] The rotating shaft 8 includes a first end portion 8b protruding axially from the first end 5a of the motor housing main body 6 and a second end portion 8c protruding axially from the second end 5b of the motor housing main body 6. For example, an impeller 2 made of aluminum is attached to the first end portion 8b which is a protruding portion of the rotating shaft 8. More specifically, a through hole is formed in the impeller 2 along the rotation axis X, and the first end portion 8b of the rotating shaft 8 is inserted into this through hole. For example, a male thread is formed on the peripheral surface of the first end portion 8b. A boss portion 2a protruding in the back direction is formed at the central portion on the base end side of the impeller 2.

[0018] The motor housing main body 6 includes a first opening formed at the tip side of the insertion hole 6a and a second opening formed at the base end side of the insertion hole 6a. The insertion hole 6a includes a first cylindrical portion 6b extending from the first opening toward the base end side, an annular first step portion 6c whose diameter is reduced from the first cylindrical portion 6b, a second cylindrical portion 6d extending from the first step portion 6c toward the base end side, an annular second step portion 6e whose diameter is reduced from the second cylindrical portion 6d, a third cylindrical portion 6f extending from the second step portion 6e toward the base end side, an annular third step portion 6g whose diameter is increased from the third cylindrical portion 6f, and a fourth cylindrical portion 6h extending from the third step portion 6g to the second opening. In other words, the diameter of the first cylindrical portion 6b is larger than the diameter of the second cylindrical portion 6d. The diameters of the second cylindrical portion 6d and the fourth cylindrical portion 6h are each larger than the diameter of the third cylindrical portion 6f. The third cylindrical portion 6f is, for example, the portion having the smallest diameter in the insertion hole 6a of the motor housing main body 6.

[0019] A rotor 8a is fixed to the central portion in the axial direction of the rotating shaft 8. The outer diameter of the rotor 8a is larger than the diameter of the other portions of the rotating shaft 8. The rotor 8a includes a source of magnetic field such as a permanent magnet. The rotor 8a is housed in the motor housing main body 6. That is, both axial ends of the rotor 8a are located between the first end 5a and the second end 5b of the motor housing main body 6.

[0020] A coil 4 is provided inside the motor housing main body 6. The coil 4 is, for example, an electromagnetic coil. The coil 4 is fixed to the third cylindrical portion 6f (inner peripheral surface) of the motor housing main body 6. The coil 4 may include, for example, a conducting wire and a stator core which is an iron core around which the conducting wire is wound (both are not shown). The coil 4 is arranged around the rotor 8a and faces the rotor 8a with a gap therebetween. The stator including the coil 4 and the rotor 8a constitute the motor 10 of the present embodiment. The coil 4 can be energized via a wiring (not shown). By energizing the coil 4, a rotating magnetic field is generated between the coil 4 and the rotor 8a, and the rotor 8a rotates.

[0021] Regarding the arrangement of the coil 4 in more detail, the coil 4 is axially spaced apart from the first end 5a and the second end 5b of the motor housing 5. In other words, the coil 4 is axially shorter than the length between the first end 5a and the second end 5b. The coil 4 is axially shorter than, for example, the length of the third cylindrical portion 6f. The coil 4 is housed in the third cylindrical portion 6f.

[0022] As also shown in FIG. 6, one or a plurality of grooves 9 are provided in the motor housing main body 6. When the direction in which the groove 9 extends is divided into an axial component and a circumferential component, the direction in which the groove 9 extends includes at least an axial component. The groove 9 is formed, for example, in the third cylindrical portion 6f and is connected to the second step portion 6e and the third step portion 6g. The bottom of the groove 9 (the portion farthest from the rotation axis X) is radially spaced apart from the coil 4 provided in the third cylindrical portion 6f. The groove 9 defines a space that extends axially on the outer peripheral side of the coil 4.

[0023] In the present embodiment, for example, a plurality of grooves 9 are formed. The plurality of grooves 9 are formed, for example, with a predetermined angular pitch. For example, six grooves 9 are formed with an angular pitch of 60°. The plurality of grooves 9 extend axially and may be parallel to each other. One or a plurality of grooves 9 may extend helically about the rotation axis X.

[0024] The groove 9 extends axially over the region where the coil 4 is provided. In other words, the groove 9 is axially longer than the length of the coil 4.

[0025] The portion located on the tip side of the rotor 8a of the rotating shaft 8 is supported by the first bearing portion 18. The portion located on the base end side of the rotor 8a of the rotating shaft 8 is supported by the second bearing portion 11. That is, the rotating shaft 8 is rotatably supported by the first bearing portion 18 and the second bearing portion 11. The first bearing portion 18 includes a cylindrical support portion 18b that faces the rotating shaft 8 and supports the rotating shaft 8, and a flange portion 18a provided at the base end portion in the axial direction of the support portion 18b and protruding radially outward. The second bearing portion 11 includes a cylindrical support portion 11b that faces the rotating shaft 8 and supports the rotating shaft 8, and a flange portion 11a provided at the tip portion in the axial direction of the support portion 11b and protruding radially outward. The first bearing portion 18 and the second bearing portion 11 are gas bearings, and in this embodiment, they are hydrodynamic air bearings. During the operation of the centrifugal blower 1, an air layer is formed between the rotating shaft 8 and the support portions 18b, 11b due to the high-speed rotation of the rotating shaft 8, and the rotating shaft 8 is pivotally supported in a floating state from the support portions 18b, 11b. Note that the first bearing portion 18 and the second bearing portion 11 may be hydrostatic air bearings.

[0026] A first bearing plate 19 is fitted into the second cylindrical portion 6d of the motor housing main body portion 6. The first bearing plate 19 is a ring-shaped member that is fitted on the first end 5a side of the motor housing main body portion 6 and holds the first bearing portion 18. A second bearing plate 12 is fitted into the fourth cylindrical portion 6h of the motor housing main body portion 6. The second bearing plate 12 is a ring-shaped member that is fitted on the second end 5b side of the motor housing main body portion 6 and holds the second bearing portion 11.

[0027] Referring to FIGS. 1 and 2, the second bearing plate 12 will be described. Note that the first bearing plate 19 may have the same structure as the second bearing plate 12. The first bearing plate 19 and the first bearing portion 18 may have a structure that is plane-symmetric with the second bearing plate 12 and the second bearing portion 11 with respect to a plane perpendicular to the rotation axis X, for example. Hereinafter, only the second bearing plate 12 will be described, and a detailed description of the first bearing plate 19 will be omitted.

[0028] As shown in FIG. 2, the second bearing plate 12 includes an annular rim portion 12a that fits into the fourth cylindrical portion 6h of the motor housing main body portion 6, a cylindrical hub portion 12c to which the second bearing portion 11 is fixed, and a plurality of spoke portions 12b that connect the rim portion 12a and the hub portion 12c. An insertion hole 12d that penetrates in the axial direction is provided in the hub portion 12c. The support portion 11b and the rotating shaft 8 supported by the support portion 11b are inserted into this insertion hole 12d.

[0029] The rim portion 12a of the second bearing plate 12 is fitted into the fourth cylindrical portion 6h of the motor housing main body portion 6 and is fixed to the third step portion 6g by bolts or the like. The flange portion 11a of the second bearing portion 11 is fixed to the hub portion 12c of the second bearing plate 12 by bolts or the like. Thereby, the second bearing portion 11 is fixed to the hub portion 12c. The second bearing plate 12 restrains displacement in the axial direction and radial direction of the second bearing portion 11.

[0030] A plurality of vent holes 14 that penetrate in the axial direction are provided on the outer peripheral side of the hub portion 12c of the second bearing plate 12. These vent holes 14 communicate with the space on the second end 5b side of the motor housing 5 and the opening on the base end side of the third cylindrical portion 6f. The region between the rim portion 12a and the hub portion 12c that is not blocked by the spoke portion 12b serves as the vent hole 14.

[0031] The vent hole 14 is provided on the second end 5b side of the motor housing 5 and communicates with an inverter chamber 56 described later, and also communicates with the insertion hole 6a of the motor housing main body portion 6. A plurality of vent holes 14 are formed in the second bearing plate 12 at a predetermined angular pitch, for example. Note that a filter (not shown), such as a dustproof filter, may be provided in the vent hole 14.

[0032] On one hand, the first bearing plate 19 also includes a rim portion, a hub portion, and a plurality of spoke portions. The rim portion of the first bearing plate 19 is fitted into the second cylindrical portion 6d of the motor housing main body portion 6 and is fixed to the second step portion 6e. The flange portion 18a of the first bearing portion 18 is fixed to the hub portion of the first bearing plate 19. The first bearing plate 19 restrains the displacement of the first bearing portion 18 in the axial direction and the radial direction. A plurality of openings 20 are formed on the outer peripheral side of the hub portion, for example, at a predetermined angular pitch. The openings 20 communicate with the openings on the tip side of the third cylindrical portion 6f. That is, the openings 20 communicate with the insertion hole 6a of the motor housing main body portion 6.

[0033] Subsequently, with reference to FIGS. 1 and 3(A) to 3(C), the flow path forming plate 23 provided at the first end 5a of the motor housing 5 will be described. As shown in FIGS. 1 and 3(A), an annular flow path forming plate 23 is fitted into the first cylindrical portion 6b of the motor housing main body portion 6. The flow path forming plate 23 includes an annular outer peripheral plate portion 23a that fits into the first cylindrical portion 6b and an inner peripheral plate portion 23b that is continuous with the inside of the outer peripheral plate portion 23a. A circular flow path forming hole 23c that penetrates in the axial direction is formed at the center of the inner peripheral plate portion 23b.

[0034] As shown in FIGS. 1 and 3(B), the inner peripheral plate portion 23b is thinner than the thickness of the outer peripheral plate portion 23a in the axial direction. More specifically, the outer peripheral plate portion 23a has a constant thickness. The inner peripheral plate portion 23b is inclined from the inner peripheral end of the outer peripheral plate portion 23a toward the flow path forming hole 23c and becomes thinner toward the flow path forming hole 23c. The back surface of the flow path forming plate 23 facing the insertion hole 6a (facing the coil 4) is flat, but the surface of the flow path forming plate 23 on the opposite side includes a recessed portion 23d (see FIGS. 3(A) and 3(C)) at the center. Note that the flow path forming plate 23 may protrude from the first opening on the tip side of the motor housing main body portion 6. That is, a part of the flow path forming plate 23 in the thickness direction (axial direction) may be fitted into the first cylindrical portion 6b.

[0035] The flow path forming plate 23 is axially spaced apart from the first bearing plate 19. The flow path forming plate 23 is also separated from the first bearing portion 18 attached to the first bearing plate 19. That is, a space 24 extending in the radial direction is formed between the flow path forming plate 23 and the first bearing plate 19. The opening 20 of the first bearing plate 19 described above communicates the insertion hole 6a of the motor housing main body portion 6 and the space 24.

[0036] The flow path forming holes 23c provided in the flow path forming plate 23 are formed, for example, around the rotation axis X. The flow path forming holes 23c form an exhaust port (first opening) 25 provided on the first end 5a side of the motor housing 5. The flow path forming holes 23c, that is, the exhaust port 25, communicate with the insertion hole 6a, the opening 20, and the space 24. The rotation shaft 8 is inserted through the flow path forming holes 23c. In the present embodiment, the exhaust port 25 is smaller than the ventilation port 14. Note that the size of the exhaust port 25 may be changed as appropriate.

[0037] The motor housing 5 is constituted by the above-described motor housing main body portion 6, the second bearing plate 12, the first bearing plate 19, the flow path forming plate 23, etc. A housing internal flow path 50 that communicates the ventilation port 14 and the exhaust port 25 is formed in the motor housing 5. The housing internal flow path 50 is formed in the gap between the inner wall surface of the motor housing main body portion 6 and the coil 4, the rotation shaft 8, the second bearing plate 12, the second bearing portion 11, the first bearing plate 19, and the first bearing portion 18.

[0038] As shown in FIG. 1, an impeller 2 attached to the first end portion 8b of a rotating shaft 8 is housed in an impeller housing 3. The impeller housing 3 includes an opening 30a which is a suction port provided on the tip side in the axial direction, a suction flow path 30 extending from this opening 30a toward the base end side, a diffuser (annular flow path) 29 formed so as to communicate with the suction flow path 30 and surround the impeller 2, a scroll 31 provided on the outer periphery of the diffuser 29 and communicating with the diffuser 29, and an air outlet provided downstream of the scroll 31. The impeller housing 3 includes, for example, an impeller housing main body portion 26 and a disk-shaped closing plate 27 attached to the base end side of the impeller housing main body portion 26.

[0039] The scroll 31 is formed in the impeller housing main body portion 26. The impeller housing main body portion 26 includes a circular opening 30a of the suction flow path 30 formed on the tip side, and a circular opening 39 formed on the base end side which faces the opening 30a in the axial direction and communicates with the suction flow path 30.

[0040] The closing plate 27 is disposed on the back side (rotor 8a side) of the impeller 2. The closing plate 27 is, for example, fitted into the opening 39 on the base end side of the impeller housing main body portion 26. The closing plate 27 and the impeller housing main body portion 26 are fixed to each other by, for example, bolts or the like. The closing plate 27 includes a first surface 27f provided on the impeller 2 side and a second surface 27g provided on the motor housing 5 side. The first surface 27f, together with the impeller housing 3, defines the diffuser 29. An O-ring 28 is disposed on the outer periphery of the opening B of the impeller housing main body portion 26. The flow path of the main stream 32 is sealed by the impeller housing main body portion 26 and the closing plate 27 sandwiching the O-ring 28.

[0041] On the second surface 27g, a concave surface (opposing surface) 27a that is recessed toward the impeller 2 side is formed. That is, the concave surface 27a is disposed between the motor housing 5 and the impeller 2. In the axial direction, the first end 5a of the motor housing main body 6 is located on the impeller 2 side with respect to the second surface 27g of the closing plate 27. The first end 5a of the motor housing main body 6 enters the recess formed by the concave surface 27a. In other words, the concave surface 27a receives the first end 5a of the motor housing main body 6. The concave surface 27a faces the motor housing 5 on the first end 5a side in the axial direction.

[0042] The first end 5a of the motor housing main body 6 and the concave surface 27a are separated from each other in the axial direction. An exhaust passage 33 that communicates the exhaust port 25 with the outside air is formed between the first end 5a of the motor housing main body 6 and the concave surface 27a.

[0043] The shape of the closing plate 27 will be described in more detail. A circular through-hole 27h that penetrates in the axial direction is formed at the center of the closing plate 27. A boss portion 2a provided on the back surface of the impeller 2 is inserted into this through-hole 27h. That is, the boss portion 2a penetrates the closing plate 27. The length of the boss portion 2a in the axial center direction substantially coincides with the length of the through-hole 27h of the closing plate 27 in the axial center direction. In this way, a part of the back surface of the impeller 2 is located on the motor housing 5 side of the concave surface 27a.

[0044] Referring to FIG. 5, the structure of the closing plate 27 around the impeller 2 will be described in more detail. As shown in FIG. 5, the closing plate 27 includes a seal portion 27k that faces the boss portion 2a of the impeller 2 on the inner diameter side. The seal portion 27k is formed at the peripheral edge of the above-described through hole 27h. The seal portion 27k seals the motor housing main body portion 6 (motor housing 5) and the impeller 2. The seal portion 27k includes an annular recess 27n that is spaced radially outward from the boss portion 2a, and annular protrusions 27m that are formed on both axial sides of the recess 27n and protrude from the bottom of the recess 27n toward the boss portion 2a of the impeller 2. That is, a groove is formed in the inner peripheral surface of the seal portion 27k over the circumferential direction. The groove of the seal portion 27k in the present embodiment is rectangular in the axial cross section. The boss portion 2a of the impeller 2 and the protrusion 27m of the seal portion 27k are spaced apart in the radial direction. The seal portion 27k forms a non-contact seal structure between the boss portion 2a of the impeller 2 and itself.

[0045] As shown in FIG. 1, the recessed surface 27a of the closing plate 27 includes a plurality of inclined portions. The recessed surface 27a includes a first inclined portion 27b, a second inclined portion 27c, a third inclined portion 27d, and a fourth inclined portion 27e from the outer peripheral side. An annular flat portion is formed between these inclined portions. The first inclined portion 27b and the second inclined portion 27c are located on the outer peripheral side of the first cylindrical portion 6b of the motor housing main body portion 6. The first inclined portion 27b extends in the axial direction from the tip side (impeller 2 side) to the base end side (coil 4 side) from the first end 5a of the motor housing main body portion 6. The step of the fourth inclined portion 27e is smaller than any of the steps of the first inclined portion 27b, the second inclined portion 27c, and the third inclined portion 27d.

[0046] The recessed surface 27a composed of these inclined portions and flat portions faces the flow path forming plate 23 provided at the first end 5a of the motor housing 5, and a radially extending exhaust flow path 33 is formed between the recessed surface 27a and the flow path forming plate 23. The exhaust flow path 33 communicates with the exhaust port 25 at the center and communicates with the outside air at the outer peripheral end.

[0047] Note that the closing plate 27 is formed with a screw seat portion (not shown) protruding toward the base end side at a predetermined angular pitch. The closing plate 27 and the motor housing main body 6 are fastened with bolts or the like via the screw seat portion. Alternatively, the closing plate 27 and the motor housing main body 6 are fastened with bolts or the like in a state where the flow path forming plate 23 is sandwiched between the screw seat portion and the motor housing main body 6. The impeller housing 3 and the motor housing 5 are connected with the closing plate 27 interposed therebetween. And an exhaust flow path 33 is formed between the flow path forming plate 23 and the closing plate 27.

[0048] A tip-side medium diameter portion 8d is formed on the tip side of the rotation shaft 8 with respect to the flow path forming plate 23. A cooling fan 34 made of, for example, aluminum is inserted into the tip-side medium diameter portion 8d. The cooling fan 34 is provided in the exhaust flow path 33 so as to face the exhaust port 25.

[0049] As shown in FIGS. 1, 4(A) and 4(B), the cooling fan 34 includes a boss portion 35a through which the tip-side medium diameter portion 8d of the rotation shaft 8 is inserted. An insertion hole 34a is formed in the boss portion 35a, and the tip-side medium diameter portion 8d is inserted into the insertion hole 34a. On the other hand, an annular stepped portion 8f having a diameter larger than that of the tip-side medium diameter portion 8d is formed continuously with the tip-side medium diameter portion 8d on the rotation shaft 8. This stepped portion 8f is located between the motor housing main body 6 and the impeller 2 and faces the boss portion 2a of the impeller 2.

[0050] In addition, a tip-side small diameter portion 8e is formed on the tip side of the tip-side medium diameter portion 8d. The tip-side small diameter portion 8e corresponds to the above-described first end portion 8b. The impeller 2 is inserted into the tip-side small diameter portion 8e. A fastening nut is screwed onto the tip side of the impeller 2. By tightening this fastening nut, an axial force is generated, and the impeller 2 and the cooling fan 34 are attached to the rotation shaft 8. In other words, a pressing force is generated from this fastening nut against the boss portion 2a of the impeller 2 and the cooling fan 34. That is, the boss portion 35a of the cooling fan 34 and the impeller 2 are sandwiched between the stepped portion 8f of the rotation shaft 8 and the fastening nut.

[0051] The impeller 2 presses the boss portion 35a of the cooling fan 34 with the boss portion 2a which is a part of the back surface. A gap is formed between the hub portion of the impeller 2 and the cooling fan 34, and the above-described closing plate 27 is located in this gap.

[0052] As shown in FIGS. 4(A) and 4(B), the cooling fan 34 includes a boss portion 35a, an insertion hole 34a formed in the boss portion 35a, a disk portion 35 extending radially outward from the end surface on the tip side of the boss portion 35a, and a plurality of blade portions (swirling blades) 36 erected on the disk portion 35 and protruding toward the base end side. That is, the blade portions 36 are attached to the first end portion 8b of the rotating shaft 8 via the disk portion 35.

[0053] The blade portions 36 are arranged between the exhaust port 25 and the exhaust passage 33 and are rotatable together with the rotating shaft 8. The boss portion 35a and the blade portions 36 are spaced apart in the radial direction. The plurality of blade portions 36 are spaced apart from each other in the circumferential direction and are arranged, for example, at equal intervals. Each blade portion 36 includes an inner end 36b which is the end closer to the rotating shaft 8 and an outer end 36a which is the end farther from the rotating shaft 8, and extends between the inner end 36b and the outer end 36a. The outer end 36a is located on the upstream side in the rotation direction R of the rotating shaft 8 with respect to the inner end 36b. Each blade portion 36 extends in a direction opposite to the rotation direction R from the inner end 36b toward the outer end 36a. The blade portions 36 are formed, for example, up to the vicinity of the outer peripheral end of the disk portion 35.

[0054] As shown in FIG. 1, the boss portion 35a of the cooling fan 34 is located on the inner circumferential side of the flow path forming plate 23. The diameter of the cooling fan 34 is larger than the diameter of the exhaust port 25 of the flow path forming plate 23. More specifically, the blade portion 36 extends to the outer circumferential side beyond the flow path forming hole 23c (see FIG. 3(B)) of the flow path forming plate 23. In other words, the exhaust port 25 is located inside the outer end 36a of the blade portion 36. The outer end 36a of the blade portion 36 is provided within the range of the recessed portion 23d of the flow path forming plate 23 in the radial direction. A part of the blade portion 36 (the tip portion farthest from the disk portion 35 in the axial direction) may enter the recessed portion 23d of the flow path forming plate 23. In other words, the recessed portion 23d of the flow path forming plate 23 may receive a part of the blade portion 36.

[0055] Subsequently, with reference to FIGS. 1 and 7, the inverter unit 51 will be further described. FIG. 7 is a cross-sectional view taken along line VII-VII in FIG. 1. In the description of the inverter unit 51, when simply using the terms "axial direction", "radial direction" and "circumferential direction", it means the rotational axis direction (rotation axis line X direction), the rotational radial direction and the rotational circumferential direction of the rotor 8a and the rotating shaft 8.

[0056] The inverter unit 51 is disposed adjacent to the proximal end side of the motor unit 41. The inverter unit 51 includes an inverter unit 52 that supplies driving power to the motor unit 41, and an inverter housing 53 that houses the inverter unit 52. The inverter housing 53 is connected to the motor housing 5 in the axial direction and has a cylindrical shape coaxial with the motor housing 5.

[0057] The inverter housing 53 has a cylindrical side wall 54 that extends in the axial direction with the rotation axis line X as the cylinder axis. The inverter housing 53 also has a disk-shaped lid portion 55 that closes the end face on the proximal end side of the side wall 54. The inverter unit 52 is housed in the inverter chamber 56 surrounded by the side wall 54 and the lid portion 55. The inverter chamber 56 communicates with the inside of the motor housing 5 through the ventilation port 14.

[0058] In the present disclosure, substantially the entire side wall 54 is composed of a cylindrical dust-proof air filter 57. The air filter 57 allows external air to pass into the inverter chamber 56 while capturing dust. Note that the side wall 54 may include a framework portion (not shown) that holds the cylindrical structure of the air filter 57. A structure may be adopted in which the cylindrical air filter 57 is covered on the outer periphery of the framework portion of the side wall 54. With the above configuration, substantially the entire side wall 54 functions as an air intake 58 that sucks the cooling air 38 from the outside into the inverter chamber 56. As described above, the side wall 54 of the inverter housing 53 is provided with the air intake 58, and the air filter 57 is provided at the air intake 58.

[0059] The inverter unit 52 is attached to the lid portion 55 and extends in the rotational axis direction. The inverter unit 52 is arranged so as to be axially aligned with the coil 4. When viewed from the radial direction, the inverter unit 52 and the coil 4 are arranged at positions that do not overlap each other (or it can be said that the inverter unit 52 and the coil 4 are arranged at positions that do not axially overlap each other). Further, the inverter unit 52 is arranged in a region where the rotational axis X intersects inside the air intake 58 (or it can be said that there is an overlap between the position of the air intake 58 in the rotational axis direction and the position of the inverter unit 52 in the rotational axis direction. Further, the inverter unit 52 is radially opposed to the air intake 58 with a heat sink, which will be described later, interposed therebetween). The inverter unit 52 is arranged around the rotational axis X in a region relatively close to the rotational axis X (or it can be said that the inverter unit 52 surrounds the rotational axis X and is arranged in the circumferential direction).

[0060] Also, when viewed in the radial direction, a part of the proximal end side of the rotation shaft 8 has an overlapping positional relationship with the inverter unit 52 (or, the rotational axis direction position of a part of the proximal end side of the rotation shaft 8 overlaps with the rotational axis direction position of the inverter unit 52. Also, a part of the proximal end side of the rotation shaft 8 faces the inverter unit 52 in the radial direction.). More specifically, a recess 52a for avoiding interference with the proximal end portion of the rotation shaft 8 is provided in a portion on the rotation axis line X of the inverter unit 52. The proximal end portion of the rotation shaft 8 is inserted into the recess 52a and is not in contact with the inverter unit 52. That is, the inverter unit 52 is formed so as to surround the proximal end side of the rotation shaft 8 in the circumferential direction (a part of the proximal end side of the rotation shaft 8 is surrounded by the inverter unit 52 around the rotational axis direction). Note that the inverter unit 52 is not necessarily a single-piece object as schematically shown in FIGS. 1 and 7, etc., and may be an aggregate of circuit boards on which electronic components are mounted. In this case, the above-described recess 52a is configured as a gap between the circuit board and the electronic components, and the proximal end portion of the rotation shaft 8 is inserted into the gap.

[0061] The inverter unit 52 has an inverter circuit (not shown) constructed on a circuit board. The inverter circuit supplies current to the coil 4 to control the rotation of the rotor 8a. Although detailed illustration of the inverter circuit is omitted, the electronic components constituting the inverter circuit include a plurality (three in this embodiment) of semiconductor elements 59 that are the main heat generation sources during operation. The semiconductor element 59 is a switching element such as an IGBT, for example. The semiconductor element 59 is disposed at the outermost peripheral portion in the radial direction of the inverter unit 52. A plurality of heat sinks 61 are attached to the outer peripheral portion of the inverter unit 52. Each heat sink 61 is in close contact with the semiconductor element 59. The heat sink 61 is disposed so as to project radially outward from the inverter unit 52 and faces the intake port 58 with a gap therebetween.

[0062] Next, the operation of the centrifugal blower 1 will be described. The centrifugal blower 1 can be used, for example, for blowing or sucking air. When the centrifugal blower 1 is used for blowing, an object to be blown is provided at the tip (i.e., the downstream side) of the outlet of the main flow 32. When the centrifugal blower 1 is used for sucking, an object to be sucked is provided in front of (i.e., the upstream side) the suction port (opening 30a) of the main flow 32.

[0063] When power is supplied from the inverter unit 52 to the coil 4 through wiring (not shown), a rotating magnetic field is generated between the coil 4 and the rotor 8a of the rotating shaft 8, and the rotating shaft 8 rotates.

[0064] As the rotating shaft 8 rotates, the impeller 2 rotates, and due to the rotation of the impeller 2, the main flow 32 is sucked into the impeller housing 3. When the centrifugal blower 1 is used for sucking, air is sucked from a predetermined object to be sucked. When the centrifugal blower 1 is used for blowing, the main flow 32 sucked into the impeller housing 3 is blown to a predetermined object to be blown through the diffuser 29 and the scroll 31.

[0065] Also, during the operation of the centrifugal blower 1, the cooling fan 34 rotates together with the impeller 2. Due to the rotation of the cooling fan 34, the inside of the motor housing 5 and the inverter chamber 56 are sucked from the exhaust port 25. Since the inside of the motor housing 5 and the inverter chamber 56 become negative pressure, outside air is sucked into the inverter chamber 56 as cooling air 38 through the intake port 58. This cooling air 38 mainly passes through the intake port 58 toward the radially inner side and contacts the heat sink 61 facing the intake port 58. Thereby, the semiconductor element 59 of the inverter unit 52 is cooled via the heat sink 61.

[0066] Thereafter, the cooling air 38 flows into the motor housing 5 from the inverter chamber 56 through the ventilation port 14. Thereafter, the cooling air 38 flows through the housing internal flow path 50 formed in the motor housing main body 6 and between the coil 4 and the rotor 8a. When the cooling air 38 flows through the housing internal flow path 50, the cooling air 38 may also flow into the groove 9 formed on the inner peripheral surface of the motor housing main body 6.

[0067] The cooling air 38 that has flowed through the motor housing main body 6 reaches the space 24 through the opening 20. The cooling air 38 that has reached the space 24 is deflected toward the center by the flow path forming plate 23. The cooling air 38 deflected toward the center is exhausted to the outside of the motor housing 5 from the exhaust port 25.

[0068] The cooling air 38 exhausted from the exhaust port 25 and sucked by the cooling fan 34 is exhausted radially outward, flows through the exhaust flow path 33, is guided to the concave surface 27a including a plurality of inclined portions, and is exhausted to the outside of the centrifugal blower 1.

[0069] During the operation of the centrifugal blower 1, heat generating sources such as the coil 4 including the conducting wire and the stator core generate heat. However, the coil 4 is cooled by the cooling air 38 flowing through the motor housing main body 6, and is further cooled by the heat radiating fins 7 that exchange heat with the outside air. Examples of heat generating sources other than the coil 4 include the rotor 8a including permanent magnets, the first bearing portion 18 and the second bearing portion 11, and the air gap. The air gap is the flow of air in the rotational direction (rotation direction R) of the rotor 8a that may occur between the rotor 8a and the coil 4. The air gap causes windage loss. Also, as described above, in the inverter unit 52, the semiconductor element 59 is the main heat generating source during operation. The semiconductor element 59 is cooled by the cooling air 38 via the heat sink 61. In the present embodiment, all of the above heat generating sources are directly or indirectly cooled.

[0070] The housing internal flow path 50 formed in the motor housing 5 functions as a motor cooling flow path that allows the cooling air 38 to pass through and cool the motor 10. Further, the exhaust flow path 33 formed at a position between the motor housing 5 and the impeller 2 functions as a fan housing flow path that houses the cooling fan 34 and allows the cooling air 38 to pass through in the radial direction. Further, the inverter chamber 56 formed in the inverter housing 53 functions as an inverter cooling flow path that allows the cooling air 38 to pass through and cool the inverter unit 52. And the above exhaust flow path 33, the housing internal flow path 50, and the inverter chamber 56 are arranged axially along the rotation shaft 8 and communicate with each other.

[0071] The operation and effect of the centrifugal blower 1 of the present embodiment described above will be described. In the centrifugal blower 1, as shown in FIG. 1, the inverter unit 52 and the coil 4 are arranged side by side in the axial direction. Therefore, both the inverter unit 52 and the coil 4 of the motor unit 41 can be cooled by the cooling air 38 flowing in one direction in the axial direction. Specifically, the inverter housing 53 and the motor housing 5 have a coaxial cylindrical shape with respect to each other, and both are connected in the axial direction. Since the inside of the motor housing 5 and the inside of the inverter housing 53 communicate with each other, a cooling flow path connected in series in the axial direction is formed across the inside of the motor housing 5 and the inside of the inverter housing 53.

[0072] A cooling fan 34 is arranged on the tip side of the motor housing 5, and the side wall 54 of the inverter housing 53 serves as an air inlet 58. During operation of the centrifugal blower 1, the cooling air 38 flows from the air inlet 58 to the cooling fan 34. That is, the cooling air 38 sequentially passes through the inside of the inverter housing 53 and the inside of the motor housing 5. By this cooling air 38, the upstream inverter unit 52 and the downstream coil 4 and the like are cooled. In this way, the flow paths of the cooling fan 34 and the cooling air 38 for cooling the coil 4 and the like and the inverter unit 52 are shared. As a result, the centrifugal blower 1 can be downsized as compared with the case where a cooling fan for cooling the coil 4 and the like and a cooling fan for cooling the inverter unit 52 are provided separately.

[0073] Further, in the centrifugal blower 1, an inverter unit 51 is arranged adjacent to the motor unit 41 in the axial direction. And the air filter 57 of the air inlet 58 provided on the side wall 54 of the inverter housing 53 has a cylindrical shape with the rotation axis X as the cylinder axis. According to this structure, compared with the structure in which the air inlet is provided on the end face orthogonal to the axial direction, a wider filter area of the air filter 57 can be ensured.

[0074] In this structure, the cylindrical hollow portion of the air filter 57 is likely to become a dead space in order to widen the above filter area, but the hollow portion is effectively utilized as an installation space for the inverter unit 52. Further, the inverter unit 52 is arranged at a position radially inside the diameter of the air inlet 58, and the heat sink 61 is installed so as to face the air inlet 58. According to this arrangement, the cooling air 38 sucked through the air inlet 58 is likely to contact the heat sink 61. Also, by adjusting the axial dimension of the inverter unit 51, the filter area of the air filter 57 can be adjusted without affecting the radial dimension. Therefore, design changes, etc. of the filter area of the air filter 57 are also relatively easy.

[0075] Further, in the centrifugal blower 1, since the inverter unit 52 is arranged in the region where the rotation axis X intersects, a flow space for the cooling air 38 is secured between the inverter unit 52 and the air inlet 58. And the heat sink 61 can be arranged in the space and the cooling efficiency is improved.

[0076] Also, if the inverter unit 52 is arranged at a position close to the rotation axis X in the radial direction, there is a possibility that the inverter unit 52 and the rotation shaft 8 may interfere with each other. To avoid this interference, if the inverter unit 52 is arranged far away from the rotation shaft 8 in the axial direction, the axial dimension of the inverter unit 52 will become large. On the other hand, in the centrifugal blower 1, as viewed in the radial direction, a part of the rotation shaft 8 is arranged so as to overlap with the inverter unit 52. With this configuration, while avoiding the interference between the inverter unit 52 and the rotation shaft 8, the position of the inverter unit 52 can be brought closer to the rotor 8a side, and the axial dimension of the inverter unit 52 can be suppressed.

[0077] Also, in the centrifugal blower 1, as described above, the inverter unit 52 is fixed to the lid portion 55, and the inverter unit 52, the lid portion 55, and the heat sink 61 are integrally packaged. With this structure, if the lid portion 55 is axially removed from the side wall 54, the inverter unit 52 and the heat sink 61 will also be pulled out from the side wall 54 following the lid portion 55. Therefore, the inverter unit 52 etc. can be removed relatively easily, and the replacement work of the air filter 57 on the side wall 54 is also relatively easy.

[0078] Also, in the centrifugal blower 1, since the first bearing portion 18 and the second bearing portion 11 that axially support the rotation shaft 8 are gas bearings, there may be a problem with the bearing function when there is a lot of dust in the motor housing 5. On the other hand, since the air filter 57 is provided at the intake port 58 of the inverter section 51, the cooling air 38 that has been sufficiently dust-removed by passing through the air filter 57 flows into the motor housing 5. Therefore, the possibility of problems with the first bearing portion 18 and the second bearing portion 11 due to dust is reduced.

[0079] Through the groove 9 formed on the inner peripheral surface of the motor housing 5, the cooling air 38 can easily flow inside the motor housing 5. The cooling air 38 can easily cool heat sources such as the coil 4. For example, the cooling air 38 flowing through the groove 9 can directly cool the coil 4 and the stator core of the rotor 8a. The cooling air 38 can also indirectly cool heat sources other than the coil 4 and the stator core.

[0080] Also, the cooling fan 34 is provided on the rotating shaft 8 and rotates together with the impeller 2. Therefore, it is not necessary to separately provide a motor for rotating the cooling fan 34. Compared with the case of separately providing a motor for sucking outside air as the cooling air, it is possible to reduce the manufacturing cost of the centrifugal blower 1 and miniaturize the device.

[0081] The present invention can be implemented in various forms with various changes and improvements based on the knowledge of those skilled in the art, starting from the above-described embodiments. Also, it is possible to configure a modification of the embodiment by using the technical matters described in the above-described embodiment. The configurations of each embodiment may be appropriately combined and used.

[0082] In the above embodiment, an example where the cooling fan 34 is a centrifugal fan that sucks the cooling air 38 from the central portion and exhausts it in the outer diameter direction has been described, but it is not limited to this. The cooling fan 34 may be an axial fan provided in the exhaust port 25, or may be a fan of another type. The swirling blades may be directly attached to the rotating shaft 8. Also, in the above embodiment, the cooling air 38 flows so as to be sucked from the intake port 58 and discharged from the exhaust flow path 33, but the flow direction of the cooling air 38 may be reversed. That is, the cooling air 38 may be sucked from the exhaust flow path 33 and discharged from the intake port 58. In this case, the coil 4 etc. of the motor unit 41 are cooled on the upstream side of the cooling air 38, and the inverter unit 52 is cooled on the downstream side. Also, in the above embodiment, the intake port 58 is provided on the side wall 54, but the intake port may be provided on the lid portion 55. Also, intake ports may be provided on both the side wall 54 and the lid portion 55.

[0083] In the above-described embodiment, the cooling structure using the centrifugal blower 1 has been described as an example. However, the present invention is also applicable to a centrifugal compressor. The fluid machine to which the present invention is applied may be an axial-flow type blower or compressor.

Explanation of Reference Numerals

[0084] 1 Centrifugal blower (fluid machine) 2 Impeller 4 Coil (stator) 5 Motor housing 8 Rotating shaft 8a Rotor 10 Motor 11 Second bearing portion (gas bearing) 18 First bearing portion (gas bearing) 33 Exhaust flow path (fan housing flow path) 34 Cooling fan 38 Cooling air 41 Motor portion 50 Flow path inside housing (motor cooling flow path) 51 Inverter portion 52 Inverter unit 53 Inverter housing 54 Side wall 55 Cover portion 56 Inverter chamber (inverter cooling flow path) 57 Air filter 58 Intake port 61 Heat sink X Rotation axis line

Claims

1. a motor unit including a motor that rotates a rotation shaft of the impeller and a motor housing that accommodates the motor; an inverter section including an inverter unit that supplies driving power to the motor section and an inverter housing that is connected to the motor housing and that accommodates the inverter unit; a cooling fan that is provided on the rotating shaft separately from the impeller and causes cooling air to flow through the inverter housing and the motor housing in sequence, the inverter housing has a cylindrical side wall surrounding a rotation axis of the rotating shaft and extending in a direction of the rotation axis, an intake port provided in the side wall for drawing in the cooling air from the outside, and a cover attached to the side wall so as to close an end of the side wall, The inverter unit is disposed at a position facing the intake port in a rotational radial direction, is fixed to the lid portion, and is removable from the side wall together with the lid portion.

2. The fluid machine according to claim 1 , wherein a heat sink facing the intake port is attached to an outer periphery of the inverter unit.

3. The fluid machine according to claim 1 , wherein the inverter housing has an air filter provided at the intake port.

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