WO2019106761A1 - Centrifugal fan and dynamo-electric machine - Google Patents

Abstract

A centrifugal fan comprising a main plate, a plurality of vanes, and a plurality of blades, wherein when the angle forming the circumferential direction of the centrifugal fan is defined as the inlet placement angle, the shape of each blade at the front edge part is formed so that the inlet placement angle of the blade varies in accordance with the height in the rotation axis direction of the centrifugal fan, and is formed so that the inlet placement angle has a maximum extreme value between the main plate side and the intake side of the blade.

Description

Centrifugal fan and rotating electric machine

The present invention relates to a centrifugal fan for improving cooling performance, and a rotary electric machine equipped with the centrifugal fan.

Centrifugal fans are used to transport gases such as air or liquids such as refrigerants. For example, the centrifugal fan of Patent Document 1 includes a plurality of blades arranged in the circumferential direction, and a disk-shaped or bowl-shaped hub provided at one end in the axial direction of the blades.

There is also a centrifugal fan with an annular shroud at the end of the plurality of circumferentially arranged vanes opposite to the hub. Conventionally, in such a centrifugal fan, high efficiency and low noise have been achieved by suppressing separation occurring at the front edge of each blade (see, for example, Patent Documents 1 to 3).

JP, 2014-202198, A Japanese Patent Application Laid-Open No. 2-7099 Japanese Patent Application Laid-Open No. 9-201009

However, the prior art has the following problems.
The structure of the centrifugal fan described in Patent Document 1 and Patent Document 2 has a low noise effect because the noise generated at the front edge of the blade is reduced. On the other hand, these centrifugal fans have a problem that the flow rate is simultaneously reduced.

Moreover, the centrifugal fan described in Patent Document 3 reduces the noise source by having a structure in which the suction portion of the blade leading edge is rounded. However, the centrifugal fan of Patent Document 3 has a problem that it is small as an effect of noise reduction.

Furthermore, there is a problem that none of the centrifugal fans of Patent Documents 1 to 3 have the effect of increasing the flow rate in the rotational axis direction.

The present invention is made to solve the above-mentioned problems, and it is an object of the present invention to provide a centrifugal fan and a rotary electric machine capable of achieving both noise reduction and improvement of cooling performance.

In order to solve the above problems, a centrifugal fan according to the present invention is a centrifugal fan including a main plate, a plurality of wings provided on the main plate, and a plurality of wings provided on each of the plurality of wings. In each of the plurality of blades, the end face on the rotary shaft side of the centrifugal fan is defined as a front edge, and at the front edge of the blades, the shape of the blade at the front edge forms an angle with the circumferential direction of the centrifugal fan When the inlet installation angle is defined, the blades are formed so that the inlet installation angle changes according to the height of the centrifugal fan in the rotational axis direction, and between the main plate side and the suction side of the blades , And is formed to have an extreme value at which the inlet installation angle is maximum.

According to the centrifugal fan according to the present invention, the noise source at the leading edge of the blade is reduced, and the flow rate flowing in the rotational axis direction is increased to improve the cooling performance. As a result, it is possible to provide a centrifugal fan capable of achieving both noise reduction and improvement of cooling performance.

1 is an overall view showing a centrifugal fan according to Embodiment 1 of the present invention. It is sectional drawing which looked at the centrifugal fan in FIG. 1 from the orthogonal | vertical direction of the rotating shaft. It is a figure explaining the entrance installation angle of the centrifugal fan in FIG. It is a graph which shows the correspondence of the height of the rotation-axis direction of a blade | wing, and an inlet installation angle. It is a figure explaining the rotation angle of the front edge position by the side of suction to the front edge position by the side of the main plate of a centrifugal fan. It is a graph which shows the relationship between the suction flow volume in a centrifugal fan, and the rotation angle of a blade | wing. It is the figure which showed the blade | wing shape in a centrifugal fan. It is the figure which applied the centrifugal fan of the present invention to a rotary electric machine. It is explanatory drawing of the blade | wing of the centrifugal fan which concerns on Embodiment 2 of this invention.

Hereinafter, an embodiment of a centrifugal fan of the present invention will be described based on the attached drawings.

Embodiment 1
FIG. 1 is a configuration diagram of a centrifugal fan 1 according to Embodiment 1 of the present invention. The centrifugal fan 1 includes a main plate 3 and a plurality of blades 2. The main plate 3 has a plate-like shape, and the rotation shaft hole 5 is provided at the center thereof. The rotation shaft hole 5 of the main plate 3 may have a shape in which the center is expanded like a bowl. Further, the main plate 3 may have a shape provided with a hole for passing a shaft for rotation to the center. Further, the main plate 3 may have a shape provided with a projection such as a rib from the strength surface.

A plurality of wings 4 are radially provided at intervals in the circumferential direction of the main plate 3. A notch is provided between adjacent wings 4. The wing 4 is provided on the wing 4 in the rotation axis direction. Arrows in FIG. 1 indicate directions in which the centrifugal fan rotates about the rotation shaft hole 4.

In the blade 2, the rotary shaft side is the front edge 2a of the blade, and the outer edge of the blade 2 is the rear edge 2b of the blade. The front edge 2 a of the blade is provided to be inclined in the rotational direction of the centrifugal fan 1. That is, as the leading edge 2 a moves away from the main plate 3 and the wing 4, the blades 2 will gradually rotate in the rotational direction of the centrifugal fan 1.

Also, by reducing the angle between the blade leading edge 2a and the circumferential direction of the circle passing through the leading edge about the rotation axis, there is no flow collision at the blade leading edge and noise generated by the blade is reduced. However, the negative pressure generated on the negative pressure surface of the blade 2 can be further reduced. Furthermore, by providing the main plate 3 with a notch, the flow rate flowing in the rotational axis direction can be increased.
As a result, the flow rate can be increased by the structure of the centrifugal fan shown in FIG.

Further, the details of the centrifugal fan 1 will be described with reference to FIGS. FIG. 2 is a cross-sectional view of the centrifugal fan in FIG. 1 as viewed from the vertical direction of the rotation axis. FIG. 3 is a view for explaining the installation angle of the centrifugal fan. FIG. 4 is a graph showing the correspondence between the height in the rotational axis direction of the blades of the centrifugal fan and the inlet installation angle. FIG. 5 is a view for explaining the rotation angle of the leading edge position on the suction side with respect to the leading edge position on the main plate side of the centrifugal fan.

The blade height in the description refers to the height of the blade in a cross section perpendicular to the rotational axis direction of the centrifugal fan 1.

In the blade 2 shown in FIG. 2, the upper side of the drawing is the suction side of the centrifugal fan 1, and the lower side of the drawing is the main plate 3 side. Cross sections at positions of blade heights A, B and C from the suction side of the centrifugal fan in the height direction of the blades 2 are taken as a cross section A, a cross section B and a cross section C, respectively.

The dotted line in FIG. 3 represents the circumference of the main plate 3 at the root portion of the notch. As shown in FIG. 3, the shape of the blade 2 in the cross section at each height of A, B and C makes an angle with the circumferential direction as an inlet installation angle θ _A , an inlet installation angle θ _B , and an inlet Set as the installation angle θ _C.

FIG. 4 shows the correspondence between the height of the blade 2 in the rotational axis direction and the inlet installation angle. The vertical axis represents the height of the blade 2 in the rotational axis direction as a ratio to the maximum blade height. The horizontal axis represents the inlet installation angle θ [°]. The solid line shows the correspondence in the present invention, and the broken line shows the correspondence in the prior art.

In the present invention, the relationship of θ _A <θ _B and θ _C <θ _B is established among the inlet installation angles θ _A , θ _B and θ _C. The height of the cross section B of inlet installation angle theta _B is maximized, it is desirable to provide in the range of from the main plate 3 to a height of approximately 2/3 of the maximum blade height. The inlet installation angle θ _A and the inlet installation angle θ _B are preferably set in the range of −10 ≦ θ _A ≦ 30, 20 ≦ θ _B ≦ 70, and θ _C is an arbitrary angle less than θ _B. Good.

As described above, the flow rate flowing in the circumferential direction with respect to the blades 2 can be reduced by reducing the inlet installation angle on the main plate 3 side. As a result, the collision between the flow passing from the suction side of the centrifugal fan 1 toward the main plate 3 and the flow in the circumferential direction decreases, and the flow rate in the rotational axis direction can be increased.
As a result of the experiment, the present blade 2 has such a leading edge shape, and the flow rate is increased by about 10% as compared with the blade 2 of the prior art, and the noise value is approximately 0. 0 in overall value. It could be reduced by 3 dB.

In the first embodiment, in the plurality of blades 2, the case where the inlet installation angles θ _A , θ _B , and θ _C are the same for all the blades has been described. However, instead of adopting the same value for all the blades, it is also possible to adopt individual values such that the relationship of θ _A <θ _B and θ _C <θ _B is established for each blade. It is possible. Furthermore, although the inlet setting angle theta _B in the section B becomes the largest, the height B may be different for each of the blades 2.

As described above, as shown in FIG. 4, the rotational noise generated by the centrifugal fan 1 without reducing the air volume of the centrifugal fan 1 by changing the inlet installation angle according to the height direction of the blades 2 Can be modulated to reduce noise. That is, the centrifugal fan according to the present invention can realize the effect of increasing the flow rate in the direction of the rotation axis after noise reduction.

As shown in FIG. 4, the inlet installation angle of the blades 2 is designed to increase at least once from the main plate 3 side to the suction side in the height direction of the blades 2 and decrease at least once. That is, the inlet installation angle has one extreme value at a certain height B in the height direction of the blade 2.

In FIG. 4, the inlet installation angle of the front edge of the blade 2 increases once from C position to B position on the main plate side and decreases once from B position to A position on the suction side. It has one extremum. Here, in the position B, the ratio to the maximum blade height is 0.4 to 0.5.

In addition, the inlet installation angle of the front edge of the blade | wing 2 may have several extreme value so that it may become large and it may become small after that several times.

FIG. 5 is a diagram for explaining the rotation angle of the leading edge position on the suction side of the centrifugal fan. The radius from the rotation center axis of the front edge of the blade 2 is approximately equal, and the rotation angle ζ [°] is the angle between the front edge on the main plate 3 and the front edge on the suction side, where O is the rotation center of the centrifugal fan 1 Set The front edge on the suction side may be rotated about the front edge on the main plate 3 side in the rotational direction.

FIG. 6 is a graph showing the relationship between the flow rate of the centrifugal fan 1 and the rotational angle 羽 根 of the blades. The vertical axis represents increase or decrease [%] of suction flow rate, and the horizontal axis represents blade rotation angle ζ [°]. When the rotation angle ζ [°] decreases within the range of 0 ° ζ 10 10 °, the suction flow rate of the centrifugal fan increases, and as it increases, the suction flow rate of the centrifugal fan decreases.

In particular, by setting the rotation angle ζ to about 7 ° or less, the noise generated from the centrifugal fan 1 can be reduced and the suction flow rate can be increased. Further, the front edge of the blade 2 is rounded in an arc shape. May be

The cross-sectional shape of the blade | wing 2 was respectively different in cross-section A, B, C of the rotating shaft direction of the blade | wing 2 shown by FIG. On the other hand, another blade shape will be described with reference to FIG.

FIG. 7 is a view showing a blade shape of the centrifugal fan 1. The front edge position of the blade 2 is D, and the rear edge position of the blade 2 is F. Further, an arbitrary position between the front edge position D and the rear edge position F of the blade 2 is E. In this case, the shape of the blade 4 from the leading edge position D of the blade 2 to the arbitrary position E differs depending on the height direction of the blade, and the shape of the blade 4 from the arbitrary position E of the blade to the trailing edge position F is It may be designed to be substantially the same in all the height directions of the blades.

A vehicular AC generator 100 as one embodiment to which the present invention is applied is shown in FIG. The automotive alternator 100 includes the centrifugal fan 83, the casing 4, the pair of bearings 5, the shaft 6, the pulley 7, the rotor 8, the stator 9, and the slip ring 10 according to the first embodiment. , A pair of brushes 11, a voltage regulator 12, a rectifying device 13, a heat sink 18, a connector 20, and a protective cover 27.

The casing 4 includes a substantially wedge-shaped front housing 31 made of aluminum and a rear housing 30. The casing 4 includes a shaft 6 rotatably supported via a pair of bearings 5. A pulley 7 is fixed to an end of the shaft 6 extending to the front side of the casing 4. In the casing 4, a rotor 8 that rotates integrally with the shaft 6 is disposed.

The stator 9 is disposed opposite to the outer periphery of the rotor 8, and the stator 9 is fixed to the casing 4. A pair of slip rings 10 for supplying an electric current to the rotor 8 is fixed to the shaft 6 extended to the rear side of the casing 4. On the surface of each slip ring 10, a pair of sliding brushes 11 and a brush holder 17 accommodating the brushes 11 are provided.

A voltage regulator 12 for adjusting the magnitude of the AC voltage generated in the stator 9 adjacent to the brush 11, a rectifier 13 for rectifying the AC voltage generated in the stator 9 into a DC voltage, a heat sink 18; A connector 20 is provided to input and output signals between the voltage regulator 12 and an external device (not shown). A protective cover 27 is provided to cover the brush holder 17 and the rectifying device 13.

The rotor 8 is formed of a field winding 81 and a field iron core 82, and is provided with an air passage for cooling the field winding. Each of the field cores 82 has six or eight claws, and is provided so as to cover the field winding 81.

The field winding 81 is a Lundell-type rotor, and is wound cylindrically and concentrically with an insulated copper wire, and an excitation current flows to generate a magnetic flux. A magnetic pole is formed by the magnetic flux generated by the field winding 81. The centrifugal fan 83 is attached to both end surfaces of the rotor 8 by welding or the like.

The operation of the vehicular AC generator 100 to which the centrifugal fan 83 according to the first embodiment of the present invention is applied will be described with reference to FIG. Due to the rotation of the rotor 8, the centrifugal fan 83 attached to the rotor 8 also rotates integrally with the rotor 8. As a result, the fluid flows in the axial direction, and the outside air is sucked into the automotive alternator 100. The outside air cools the components in the automotive alternator 100, particularly the field winding 81, and then is discharged to the outside.

By providing the centrifugal fan 83 in the rotor 8, it is possible to improve the cooling performance by increasing the fluid flowing in the axial direction inside the rotor after noise reduction is achieved.

Although the example of application of the present invention is used for such a car alternator, the present invention is not limited to this. The present invention can also be used by attaching to, for example, a rotor of a rotating electrical machine such as an on-vehicle alternating current generator, a motor, or an on-vehicle drive device.

The centrifugal fan according to the first embodiment includes a main plate, a plurality of wings provided on the main plate, and a wing provided on the wing, and the inlet installation angle of the leading edge of the wing is set to a height in the rotational axis direction of the centrifugal fan Change according to the Specifically, in the centrifugal fan according to the first embodiment, the inlet installation angle of the leading edge of the blade increases and then decreases as it goes from the main plate side to the suction side, and then the inlet installation angle is at least one pole. It has a blade with a value.

By providing such a configuration, the flow rate in the rotational axis direction of the centrifugal fan can be increased. Therefore, after reducing the noise generated from the centrifugal fan, the suction flow rate can be increased, and both noise reduction and improvement of the cooling performance can be achieved.

Each of the plurality of vanes may have vane heights having extrema of the inlet installation angle set to different heights. Thereby, it is possible to increase the flow rate in the rotational axis direction of the centrifugal fan differently for each blade. Furthermore, the shape of the blades differs depending on the direction of rotation. For this reason, without reducing the air volume of the fan, noise related to the rotational speed of the centrifugal fan can be dispersed and modulated to the frequency around it to reduce noise.

The leading edge of the blade is inclined in the direction of rotation of the centrifugal fan. Such a configuration of the blades causes the leading edge of the blades to rotate gradually and quickly in the direction of rotation of the centrifugal fan as it moves away from the main plate and the blades. As a result, noise related to the rotational speed of the centrifugal fan can be dispersed and modulated to frequencies around it to reduce noise.

In a cross section perpendicular to the rotational axis direction of each centrifugal fan of the plurality of blades, the front edge position and the rear edge position and an arbitrary position on the plane of the wing between the front edge position and the rear edge position In this case, the blades can be designed such that the curve from the leading edge position to the arbitrary position is different for each blade, and the curve from the arbitrary position to the trailing edge position is equal in at least two blades.

By providing such a configuration, noise sources present at the leading edge of the blade can be effectively reduced by making the shape of the leading edge of the blade different in the height direction of the blade. As a result, the noise generated from the centrifugal fan can be reduced. Furthermore, by equalizing the shape of the trailing edge of all the vanes in the height direction of the vanes, it is possible to suppress a decrease in suction flow rate.

For the leading edge on the main plate side, a blade can be designed in which the rotational direction ζ of the leading edge on the suction side is 0 ≦ 0 ≦ 10. Thereby, the suction flow rate of the centrifugal fan can be increased, and the cooling capacity can be improved. Therefore, both noise reduction and improvement of the cooling performance can be achieved.

The centrifugal fan according to the present invention can be applied to a rotating electrical machine. Such an application can increase the flow rate flowing in the direction of the rotation shaft of the rotating electrical machine. As a result, it is possible to realize a rotating electrical machine that achieves both noise reduction and improvement in cooling performance.

The centrifugal fan according to the present invention can also be configured to include an annular shroud so as to be positioned upstream and face the main plate of the blade.

Second Embodiment
The structure of the blade | wing 12 of the centrifugal fan 1 which concerns on Embodiment 2 of this invention is shown in FIG. The same reference numerals as those in FIGS. 1 to 8 in the first embodiment denote the same or similar components, and a detailed description thereof will be omitted.

As shown in FIG. 9, an arbitrary point G is set at the front edge of the blade 2, and an arbitrary point H is set at the suction side of the blade 2. The blade 2 according to the second embodiment has a structure in which the blade 2 is inclined to be bent in the rotational direction by a straight line passing through the point G and the point H.

By providing such an inclined structure, it is possible to effectively reduce the noise source present at the front edge of the blade and to reduce the noise generated from the centrifugal fan. Furthermore, as in the first embodiment, the flow rate in the rotational axis direction of the centrifugal fan can also be increased. As a result, while achieving both noise reduction and improvement in cooling performance, it is possible to realize performance improvement in noise reduction as compared to the first embodiment.

1 Centrifugal fan, 2 blades, 2a blade leading edge, 2b blade trailing edge, 3 main plate, 4 blades, 5 rotary shaft holes, 6 shafts, 8 rotors, 100 rotary electric machines, A blade height direction Position on suction side, any position between position A on suction side of blade B and position C on side of main plate, position on main plate side in height direction of blade C, front edge position of blade D, front edge of blade E Any point between and the trailing edge, the trailing edge position of the F blade, any point at the leading edge of the G blade, any point on the suction side of the H blade, O center of rotation, height of the θ _A blade Inlet installation angle of θ, Inlet installation angle of θ _B blade height B position, Inlet installation angle of θ _C blade height C position, Rotation angle of blade front edge.

Claims (7)

1. A centrifugal fan comprising a main plate, a plurality of blades provided on the main plate, and a plurality of blades provided on each of the plurality of blades,
   In each of the plurality of blades, an end face on the rotation shaft side of the centrifugal fan is defined as a front edge, and an angle between the shape of the blades at the front edge and the circumferential direction of the centrifugal fan is an inlet installation angle When defined as, the blade is formed so that the inlet installation angle changes according to the height of the centrifugal fan in the direction of the rotation axis, and between the main plate side and the suction side of the blade A centrifugal fan configured to have an extremum at which the inlet installation angle is at a maximum.
2. The centrifugal fan according to claim 1, wherein each of the plurality of blades has a blade height in the direction of the rotation axis having the extreme value set individually.
3. The centrifugal fan according to claim 1, wherein at least one of the plurality of blades is formed such that the front edge portion is inclined in a rotational direction of the centrifugal fan.
4. Each of the plurality of blades has any position on the surface of the wing between the leading edge position, the trailing edge position, the leading edge position and the trailing edge position in a cross section perpendicular to the rotation axis direction. When defining three points, the curve from the leading edge position to the arbitrary position is different for each blade, and the curve from the arbitrary position to the trailing edge position is formed to be equal in at least two blades. The centrifugal fan according to claim 1.
5. At least one of the plurality of blades defines any point in the height direction at the front edge as a first point, and any between the front edge and the rear edge on the suction side of the blades When a point is defined as a second point, according to a straight line connecting the first point and the second point, a portion corresponding to the height of the first point or more at the front edge of the blade is a centrifugal fan. The centrifugal fan according to claim 1, wherein the centrifugal fan is formed to be inclined in a direction.
6. Each of the plurality of blades has, at the front edge, a straight line connecting the central axis of rotation of the centrifugal fan and the front edge on the main plate side, and a straight line connecting the central axis of rotation and the front edge on the suction side The centrifugal fan according to claim 1, wherein when the angle formed is defined as a rotation angle ζ, 0ζ10.
7. A rotating electrical machine comprising the centrifugal fan according to any one of claims 1 to 6 in a rotor.

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