CENTRIFUGAL FAN AND ROTATING ELECTRIC MACHINE

Abstract

A centrifugal fan (1) included in a rotating electrical machine or similar device is configured with a main plate (2) having a multitude of plate-shaped blades (4) arranged in a ring shape around a periphery of an axis of rotation and formed in such a way that their diameter increases from front to back in a direction of rotation. The blade (4) is provided erected from an arm-shaped plate (3) projecting from one side of the main plate (2). At least one of the multitude of blades (4) has a curved portion (4c) in a portion of the face configuring the blade (4), and a region of the blade (4) in which the curved portion (4c) is provided is formed in a forward-facing shape in the direction of rotation. Figure for the abbreviation: Figure 1

Description

Description Title of the invention: CENTRIFUGAL FAN AND ROTATING ELECTRIC MACHINE Scope of the invention

[0001] — The present application relates to a centrifugal fan and an electrical machine rotating. Anterior artery

[0002] A centrifugal fan is used as a component of a machine rotating electrical such as an alternating current generator mounted on a vehicle. Various blade shapes have been proposed for an existing centrifugal fan, with the aim of improving airflow characteristics and reducing noise.

[0003] For example, an example in which a blade used as a fan of re- The cooling of an alternating current generator is such that a metal plate is formed in a flexed shape so as to form a predetermined angle vis-à-vis of a main plate has been disclosed (for example, see the literature document patent 1).

[0004] = In addition, noise reduction by supports of a housing that accommodates a wheel as that existing centrifugal fan, which are arranged at different intervals in a circumferential direction, has been disclosed (for example, see the document of lit- patent type 2).

[0005] Patent literature document 1: JP-A-9-154256

[0006] Patent literature document 2: Japanese patent no. 5727833

[0007] The cooling fan blade disclosed in the literature document patent 1 is of a form in which an end portion of a main plate is bent at a predetermined angle, which allows for a case where air circulation Axial flow increases, but overall airflow and air circulation centrifugal directions are limited.

[0008] — Furthermore, the centrifugal fan disclosed in the patent literature document 2 is such that, although the noise can be reduced through a crankcase modification, a A multitude of fans are the same shape, and there is no mention of a improved airflow characteristics due to shape transformation of pale. Description of the invention

[0009] — The present application was designed to solve the types of problems described below. before and aims to obtain a centrifugal fan allowing the regulation of the characteristics- risks of air circulation and improving cooling properties, by transforming a blade shape, and obtaining a rotating electrical machine that includes the centrifugal fan. A centrifugal fan disclosed in this application comprises a main plate having a multitude of plate-shaped blades provided in a ring shape in a periphery of an axis of rotation and formed in a range such that a diameter increases from front to back in a direction of rotation, and is characterized in that the blade is provided erected from a flat face portion of the main plate, at least one of the multitude of blades has a curved portion in a portion of a face portion configuring the blade, and a region of the blade in which the curved portion is provided is of a shape recessed forward in the direction of rotation. In preferred embodiments of the invention, the curved portion is provided in a rear edge portion positioned on an outer diameter side of the blade. In preferred embodiments of the invention, the curved portion is provided further along one inner diameter side than a rear edge portion positioned on an outer diameter side of the blade. In preferred embodiments of the invention, a region in which the curved portion of the blade is provided is provided in a shape such that a radius of curvature decreases in an axial direction from an end portion of the blade towards the flat face portion of the main plate. In preferred embodiments of the invention, a region in which the curved portion of the blade is provided is provided in a shape such that a radius of curvature increases in an axial direction from an end portion of the blade towards the flat face portion of the main plate. In preferred embodiments of the invention, the curved portion of the blade is provided from front to back in the direction of rotation, and the blade is formed in such a shape that a position in which the radius of curvature in the axial direction is the smallest approaches the flat face portion of the main plate when going from front to back of the blade in the direction of rotation. In preferred embodiments of the invention, when an interval between end portions at the front in the direction of rotation of two adjacent blades is maximal, the curved portion is provided in the blade positioned at the rear in the direction of rotation. Furthermore, a rotating electrical machine disclosed in this application is a rotating electrical machine in which the centrifugal fan is attached to one end of a rotor, and is characterized in that the flat face portion of the main plate is disposed on an end portion in the axial direction of a field core configuring the rotor so that the blade is positioned on one side external, and the curved portion of the blade is arranged so as to overlap in the axial direction an outer edge region of an air gap portion between claw-shaped magnetic poles configuring the field core. In preferred embodiments of the invention, the curved portion of the blade is provided further along one side of the inner diameter than a portion of the maximum outer diameter of a mounting face of the field core. In preferred embodiments of the invention, the curved portion of the blade is provided further on one side of the inner diameter than a portion of the edge of an inlet hole of a housing enclosing the centrifugal fan. According to the centrifugal fan disclosed in this application, axial airflow can be increased by the fact that a curved portion is provided in a blade and that a portion of the blade is in a forward-curved shape in a direction of rotation, which allows the airflow to be regulated in the axial direction and a centrifugal direction of the blade and improves the cooling properties. Furthermore, the rotating electrical machine disclosed in this application is such that, because the centrifugal fan is attached to a rotor, air circulation brought in an axial direction of the rotor can be increased, and cooling performance can be improved. The aforementioned objectives, features, aspects, and advantages of this application will become clearer upon reading the following detailed description of the application, taken together with the accompanying drawings. Brief description of the drawings [fig.1] is a perspective view of a centrifugal fan according to a first embodiment; [fig.2] is a characteristic diagram in which the performance of the centrifugal fan of the first embodiment is compared to that of comparative examples; [fig.3] is an enlarged view of the main portion of a centrifugal fan according to a second embodiment: [fig.4] is a cross-sectional view of a blade of a centrifugal fan of a third embodiment; [fig.5] is a cross-sectional view of a blade of a centrifugal fan of a fourth embodiment; [fig.6] is a perspective view of the main portion of a blade of a centrifugal fan of a fifth embodiment; [fig.7] is a perspective view of the main portion of the fan blade centrifugal of the fifth embodiment; [fig.8] is a cross-sectional view showing a rotating electrical machine of a seventh embodiment; and [fig.9] is a side view showing a field core of the rotating electric machine of the seventh embodiment. Detailed description First of Jisati A centrifugal fan 1 according to a first embodiment of the present application will be described with reference to Figures 1 and 2. Figure 1 is a perspective view of the centrifugal fan 1, in which the centrifugal fan 1 is used, for example, in a rotating electrical machine 100 used in a vehicle, and a blade 4 is arranged to project outwards in an axial direction on an axial end face of a rotor 8 (which will be described below). Figure 2 is a characteristic diagram in which the performance of the centrifugal fan 1 of the present application and comparative examples are shown. As shown in Figure 1, the centrifugal fan 1 is primarily configured with a main plate 2 provided in the shape of a ring on the periphery of a through hole through which a shaft 34 (which will be described below) of the rotating electrical machine 100 is inserted. The main plate 2 has a multitude of blades 4 formed in a range where diameters increase from front to back in a direction of rotation. The blade 4 is provided erected from an arm-shaped plate 3 projecting in the shape of an arm from an outer peripheral side of a flat face portion of the main plate 2. The arm-shaped plate 3 is a portion of the main plate 2, as described above, and is provided in the shape of a flat plate extending outwards in a radial direction from an outer peripheral portion of the flat face portion of the main plate 2.An angle at which the blade 4 is erected from the flat face portion of the main plate 2 can be, for example, a vertical angle (or an approximately vertical angle). At least one of the multitude of blades 4 positioned in an end portion of the main plate 2 has a curved portion 4c in a portion of a face (blade face) configuring the blade 4, and a region in which the curved portion Ac of the blade 4 is provided is of a shape recessed forward in the direction of rotation. Here, the region in which the curved portion 4c is provided in the blade 4 is such that, unlike other portions of the blade 4, a partially curved face shape is formed, whereby the region configures an inclined face. As shown in Figure |, a portion of the opening 5 which penetrates in the axial direction is provided on an inner side in the radial direction of the blade 4 in one of the multitude of arm-shaped plates 3 included in the centrifugal fan 1. Furthermore, in the example in Figure 1, fourteen arm-shaped plates 3 are arranged in the circumferential direction. A stepped portion can be formed on an inner periphery of the hole passing through the center of the main plate 2. As shown in the example in Figure 1, the fourteen arm-shaped plates 3 are arranged at varying intervals in the circumferential direction on the flat face portion of the main plate 2. Radial dimensions of the arm-shaped plate 3 are formed to be small on the front side in a direction of rotation Rot and large on the rear side in the direction of rotation Rot. Furthermore, there are also arm-shaped plates 3 whose distance between a center of rotation O and an outer edge portion in the radial direction differs among the multitude of arm-shaped plates 3, and the distances from the centers of rotation O of the blades 4 also vary. Although the curved portion 4c intended to increase airflow in the axial direction is specifically provided in the blade 4, it is more advantageous to place the curved portion Ac in the blade 4 where the distance from the center of rotation O is short to improve cooling properties. As shown in Figure 1, the blade 4 is configured as a plate in which are integrated a rear edge portion 4b positioned on the rear side in the direction of rotation (it can also be the outer side in the radial direction) and a front edge portion 4a positioned on the front side in the direction of rotation (it can also be the inner side in the radial direction). A distance between the center of rotation O of the centrifugal fan 1 and the rear edge portion 4b of the blade 4 is greater than a distance between the center of rotation O and the front edge portion 4a of the blade 4. Furthermore, a shape of the blade 4 projected onto a face perpendicular to the axis can approach an arc having a gentle curve, and the arc is formed so as to extend beyond the center of rotation O side from a line which connects the front edge portion 4a and the rear edge portion 4b. Here, in order to reduce the air cutting noise caused by the front edge portion 4a when the centrifugal fan 1 rotates, there is a case where the front edge portion 4a of the blade 4 is made to tilt in a direction towards the center of rotation O or backwards in the direction of rotation. The centrifugal fan 1, configured with the main plate 2 having the blade 4 in this way, generates an airflow that circulates outwards in a radial direction (in the centrifugal direction) along the blade 4. In doing so, the centrifugal fan 1 converts an airflow towards a central portion of the main plate 2 into an airflow that goes outwards in the radial direction. The shape of the main plate 2 is not limited to a ring shape, and it is not necessary to provide a stepped portion in the inner peripheral portion. Furthermore, the central portion of the main plate 2 may be a raised, bowl-shaped form. In addition, the number of arm-shaped plates 3, which is not limited to fourteen, may be four or more, or may be an odd number. Moreover, the multitude of arm-shaped plates 3 may be arranged at equal intervals, and a reinforcing rib may be provided on each arm-shaped plate 3. Furthermore, the shape of blade 4 projected onto the face perpendicular to the axis can be linear or S-shaped, or the shapes of the blades 4 can differ. Additionally, blade 4 can project from a position towards the center of the flat face rather than from an outer peripheral end of the arm-shaped plate 3. Moreover, a circular fairing can be arranged on the outer side, radially oriented, of blade 4. Besides the circular shape shown in Figure 1, a different shape such as an elliptical or polygonal shape may be adopted for the portion of the opening 5. In addition, in order to reduce added resistance to airflow passing through the portion of the opening 5, and to limit a decrease in the circulation speed of air flowing in the axial direction, a round shape or a chamfered round shape may be formed in an edge portion of the portion of the opening 5. Furthermore, since it is sufficient for the opening portion 5 to be disposed in the flat face portion of the main plate 2, the opening portion 5 can be disposed in a region other than the arm-shaped plate 3. Furthermore, when two adjacent arm-shaped plates 3 are close to each other, the two arm-shaped plates 3 can be integrated, and the opening portion 5 can be formed in the integrated arm-shaped plate 3. Although Figure 1 shows an example in which two openings 5 ​​are provided in the main plate 2, the number of openings 5 ​​can be adjusted. It can be one, one opening can be provided in each arm-shaped plate 3, or one opening can be provided in one of two arm-shaped plates 3 arranged sequentially around the periphery. Furthermore, a multitude of openings 5 ​​can be provided in a single arm-shaped plate 3, and the shapes of the portions of the openings 5 ​​can be made to differ variably. By increasing the number of openings 5 ​​and thus reducing the weight, the center of gravity of the centrifugal fan 1 becomes closer to the center of rotation O, which helps stabilize the rotation of the centrifugal fan 1. In this case, the arrangement, number, and size of the portion of the openings 5 ​​provided in each shaped plate arm 3 can be determined by taking into account a balance of weight in the circumferential direction of the centrifugal fan 1. The centrifugal fan 1 of the present application is such that the outer side of the blade 4 is a positive pressure face (a face on the front side in the direction of rotation) which generates air circulation, and the inner side of the blade 4 is a negative pressure face (a face on the rear side in the direction of rotation). Furthermore, the axial dimensions (height of the blade) of the blade 4 are such that the leading edge portion 4a in the direction of rotation is small, and the rear edge portion 4b is large, thus limiting air collisions in the leading edge portion 4a.That is to say, as shown in a portion of the upper end on the leading edge side 4d of the blade 4 in Figure 1, a quantity of protrusion of the portion of the upper end on the leading edge side 4d in the axial direction from the main plate 2 (the arm-shaped plate 3) is kept small, which allows the air cutting noise to be reduced more than in other portions of the blade 4. In this type of centrifugal fan 1, at least one blade 4 is such that the curved portion 4c is formed in a portion of the face portion configuring the blade 4, and the region of the blade 4 in which the curved portion 4c is provided is shaped by a twist applied forward in the direction of rotation. Here, the curved portion 4c refers to a portion that is formed, for example, in the face portion that forms the positive pressure face of the blade 4, and whose radius of curvature varies in the axial direction. There is a case where the curved portion 4c is formed so as to spread out in both the radial and axial directions along the face portion of the blade 4. In the example of the first embodiment, the curved portion 4c is provided in the trailing edge portion 4b, which is the rear of the blade 4 in the direction of rotation, or on an outer diameter side of the blade 4. In this case, the outer diameter side of the blade 4 is curved downwards in the direction of rotation, and the positive pressure face of the blade 4 is shaped in such a way that the radius of curvature increases (the curvature decreases) from the outer diameter side to an inner diameter side. As a result, the positive pressure face of the blade 4 forms a recessed curve in the trailing edge portion 4b, and can cause an increase in airflow in the axial direction. The region in which the curved portion 4c is thus provided in the blade 4 of the centrifugal fan 1 is such that the surface area of ​​the blade 4 protruding on the face perpendicular to the axis increases due to a torsion applied to the face portion of the blade 4, thereby increasing airflow in the axial direction. This means that by adjusting the curvature and a range of formation of the curved portion 4c, an equilibrium can be found between air circulations in the axial direction and in the radial direction of the centrifugal fan 1, and an improvement in cooling performance can be obtained. In the example in Figure 1, the curved portion 4c is provided in one out of every two blades 4 aligned in the circumferential direction, but the curved portion 4c may be provided in one blade 4, the curved portion 4c may be provided in a multitude of blades 4 at varying intervals, or the curved portion 4c may be provided in every blade 4. A bar graph in Figure 2 is a characteristic drawing showing comparative results of overall cooling airflow in the centrifugal and axial directions for a first comparative example, which is a centrifugal fan to which the present application does not apply and in which the curved portion 4c is not provided in the blade 4; a second comparative example, the structure of which is the same as that of the centrifugal fan in patent literature document 1 and in which the blade inclination angle is constant; and centrifugal fan 1 (the present application in Figure 2), to which the blade 4 having the curved portion 4c of the present application is applied, with the first comparative example as a reference. The overall airflow represents the sum of the airflows in the centrifugal and axial directions. Figure 2 shows, by application of the centrifugal fan 1 of the present application, that the axial airflow can be increased compared to the first and second comparative examples, without causing a decrease in centrifugal airflow, and the overall cooling airflow can be increased. Second in realization An example in which the curved portion 4c is provided on the rear edge portion 4b of the blade 4 is shown in the first embodiment, but in a second embodiment, a case in which the curved portion 4c is provided further from the inner diameter side of the blade 4 than the rear edge portion 4b will be described, using Figure 3. In Figure 3, a distance between the leading edge portion 4a (a position in the radial direction is shown as point A) of the blade 4 and the center of rotation O is RA, a distance between the rear edge portion 4b (a position in the radial direction is shown as point B) of the blade 4 and the center of rotation O is RB, and a distance between a point C on the front portion, positioned between the leading edge portion 4a and the rear edge portion 4b of the blade 4, and the center of rotation O is RC (RA < RC < RB).Point C indicates an intermediate position between the edge portions of blade 4 in the direction of rotation and the radial direction. In this case, the curved portion 4c is provided in at least one blade 4 between RA and RC, that is, further from the inner diameter side of blade 4 than the trailing edge portion 4b, whereby a portion of blade 4 is formed in a curved shape. The radial position of the curved portion 4c is shown as point D. A distance between point D and the center of rotation O is shown as RD. Because the curved portion 4c is provided in the position of blade 4 indicated by point D, a relationship RD < RC < RB is established. Even when the curved portion 4c is provided in a position towards the inner diameter side of the blade 4, the axial airflow may increase more than when the curved portion 4c is not provided, and by using this type of configuration, air cutting noise occurring in the leading edge portion 4a of the blade 4 may be limited. Although the example in Figure 3 shows a case where the rear edge portion 4b of the blade 4, in which the curved portion 4c is formed, has a diameter (RB) smaller than an outside diameter RO of the centrifugal fan 1, there is also a case where the curved portion 4c is formed so that the size of the blade 4 is equal to the outside diameter RO. In this case, a relationship RD < RC < RO is established, and the axial airflow can be increased while reducing air noise. Troisi Jisati Examples in which the arrangement of the curved portion 4c in the radial direction of the blade 4 is on the trailing edge portion 4b and further from the inner diameter side than the trailing edge portion 4b are shown in the first and second embodiments. In a third embodiment, an example of an arrangement of the curved portion 4c of the blade 4 in the axial direction will be described, with reference to Figure 4. Figure 4 is a circumferential cross-sectional view in the axial direction at point C on the front portion of the blade 4 of Figure 3. An inclined face of the blade 4 in which the curved portion Ac is provided is provided in a shape whose radius of curvature decreases (the curvature gradually increases) as the inclined face moves in the axial direction from an end portion (on an inlet side) of the blade 4 towards the flat face portion of the main plate 2.The radius of curvature on the intake side (L2) of the tip portion of the blade 4 is greater than the radius of curvature on the flat face portion (L1) of the main plate 2. By increasing the curvature in a position of the blade 4 closer to the flat face portion of the main plate 2 than to the end portion, it is possible to adjust the cooling airflow and improve the cooling properties. Fourth mode of implementation An example of the third embodiment is shown in the third embodiment where the curved portion 4c is provided in the blade 4, and the blade shape is such that the radius of curvature decreases from the inlet side to the flat face of the main plate 2 in the axial direction. In a fourth embodiment, an example of the blade shape is shown in the third embodiment where the radius of curvature increases from the inlet side to the flat face of the main plate 2 in the axial direction, which is the opposite of the blade shape in the third embodiment. This example is shown in Figure 5.By adopting a curved blade shape such that the radius of curvature increases progressively from the intake side (L2) to the flat face portion side (L1) of the main plate 2, as shown in Figure 5 in circumferential cross-section of the blade 4 in the axial direction, the cooling airflow can be adjusted and the cooling properties can be improved. A state in which an inclined face with a large curvature is provided on the inner diameter side, which is one side further from the rear of blade 4 than the portion in section, is shown in the example in Figure 5. Cinqui lisati Figures 6 and 7 also show examples of a blade shape of the centrifugal fan 1 according to a fifth embodiment of the present application. Figure 6 is a perspective view of the main portion of the blade 4 of the centrifugal fan 1, where the negative pressure face of the blade 4 is shown on the front side, and shows a radial cross-sectional view of two locations in the blade 4, at the front and rear in the direction of rotation. Figure 7 is a perspective view of the main portion of the blade 4 of the centrifugal fan 1, where the positive pressure face of the blade 4 is shown on the front side, and shows a circumferential cross-sectional view of two locations in the blade 4, at the front and rear in the direction of rotation.In Figure 7, a reference symbol (L2_F) indicating the inlet side and a reference symbol (L1_F) indicating the flat face portion side of the main plate 2 are entered into a cross-section near the leading edge portion 4a, and a reference symbol (L2_R) indicating the inlet side and a reference symbol (L1_R) indicating the flat face portion side of the main plate 2 are entered into a cross-section near the trailing edge portion 4b. In each case, the curved portion 4c is provided in a relatively wide range from the leading edge portion 4a to the trailing edge portion 4b of the face portion of the blade 4 such that the degree of curvature of the blade 4 is large on the side closest to the leading edge portion 4a, and the degree of curvature becomes smaller as it approaches the trailing edge portion 4b. As shown in Figures 6 and 7, the blade 4 is provided in such a form that a position in which the radius of curvature in the axial direction of the blade 4 becomes the smallest, moving from front to back in the direction of rotation in the region in which the curved portion 4c is provided, moves in a direction approaching the arm-shaped plate 3 (the flat face portion of the main plate 2) from the axial inlet side of the blade 4. Although the direction of movement of the position in which the radius of curvature in the axial direction becomes the smallest is indicated by an arrow as curved portion 4c, the location indicated by the arrow indicates the position in which the smallest value of the radius of curvature in the axial direction is found, and it goes without saying that the state is such that a curved shape is also formed in the face portion positioned in a periphery of the arrow. By this arrangement of the curved portion 4c in the blade 4 from front to back in the direction of rotation, and by the formation of the blade 4 so that it has a shape in which the position in which the radius of curvature in the axial direction becomes the smallest approaches the flat face portion of the main plate 2 going from front to back in the direction of rotation (as the distance from the center of rotation O increases), it is possible to obtain a blade shape in which the curvature is made to vary in the radial and axial directions, and to improve the straightening of the centrifugal fan 1. Sixi de de réalisationti The centrifugal fan | is of a configuration in which the multitude of blades A are arranged in the circumferential direction, as described above, but in a sixth embodiment, it will be described for which blade 4 of the multitude of blades 4 the curved portion 4c provided is effective in improving the cooling properties. The airflow received by the blade 4 of the centrifugal fan 1 tends to increase when the gap with the front blade 4 positioned at the front in the direction of rotation of the blade 4 increases. This means that when a gap between end portions located at the front in the direction of rotation of each of the two adjacent blades 4 of the centrifugal fan 1 is maximal, or when the gap reaches a predetermined value or greater and the airflow striking the positive pressure face of the blade 4 increases, the airflow in the axial direction can be effectively increased by the arrangement of the curved portion 4c in the rear-positioned blade 4 in the direction of rotation. Seventh realizations The centrifugal fan 1 disclosed in the first to sixth embodiments can be applied to the rotating electrical machine 100. For example, the fan The centrifugal fan 1 can be used by attaching it to the rotor 8 of the rotating electrical machine 100, which is an alternating current generator mounted on a vehicle, a motor, a vehicle-mounted drive device, or the like. Here, by way of example, an alternating current generator for use on a vehicle is shown as the rotating electrical machine 100 to which the centrifugal fan 1 of this application is applied. Figure 8 is a cross-sectional view of the rotating electrical machine 100 viewed from the side. In Figure 8, the rotating electrical machine 100 has a housing 32 formed by a front-side housing 31 and a rear-side housing 30, each approximately bowl-shaped and made of aluminum. The rotating electrical machine 100 has a shaft 34, supported by the housing 32 so as to rotate on a pair of bearings 33, and a pulley 7 fixed to an end portion of the shaft 34 projecting from a front side of the housing 32. The front-side bearing 33 is supported by the front-side housing 31, and the rear-side bearing 33 is supported by the rear-side housing 30. In addition, the rotating electrical machine 100 has the rotor 8, which is arranged inside the housing 32 by being fixed to the shaft 34 and rotates integrally with the shaft 34, and a stator 9 fixed to the housing 32 so as to enclose the rotor 8. Furthermore, the rotating electrical machine 100 has a pair of slip rings 10, which are fixed to a projecting portion of the shaft 34 projecting on a rear side of the housing 32 and supply the rotor 8 with current, a pair of brushes 11, which are housed in a brush holder 17 and which each slide on the surfaces of the slip rings 10, and a voltage regulator 12, which is arranged next to the pair of brushes 11 and regulates a quantity of an alternating voltage generated in the stator 9. In addition, the rotating electric machine 100 has a rectifier 13 which converts an alternating voltage generated in the stator 9 into a direct voltage, a connector 20 which performs a signal exchange between the voltage regulator 12 and an external device, and a protective cover 27 mounted on the rear side housing 30 so as to cover the voltage regulator 12, the rectifier 13 and the brush holder 17. The rotor 8 is a Lundell type rotor, and has a field winding 81, through which an excitation current flows and which generates a magnetic flux, and a field core 82, which is provided so as to cover the field winding 81 by being fixed to the shaft 34, which enters an axial position, and in which a magnetic pole is formed due to a magnetic flux generated in the field winding 81. The centrifugal fan 1 according to the first embodiment of the present application is disposed on a mounting face on the pulley 7 side of the rotor 8 or on a mounting face on the opposite side to the pulley 7. The stator 9 is arranged coaxially in an outer periphery of the rotor 8. The stator 9 comprises a cylindrical stator core 91 and a stator winding 92, mounted on the stator core 91, in which an alternating current is generated due to a change in the magnetic flux of the field winding 81 accompanying a rotation of the rotor 8. The stator core 91 is clamped on both sides in the axial direction between the front-side housing 31 and the rear-side housing 30. A conductor 92a of the stator winding 92 is drawn from the rear-side housing 30 and connected to a terminal 24a of a printed circuit board 24. As a result, the rectifier 13 and the stator winding 92 are electrically connected. The rectifier device 13 includes a heat sink 18, on which are mounted a multitude of rectifier elements, and the printed circuit board 24. The rotating electric machine 100, thus configured, is such that the rotational torque of a motor (not shown) is transmitted via pulley 7 to shaft 34, and the rotor 8 is set in rotation. At this moment, current is supplied via brush 11 and slip ring 10 to the field winding 81 of the rotor 8, and a magnetic flux is generated. Due to the magnetic flux, N-poles and S-poles are formed alternately in a circumferential direction in a multitude of claw-shaped magnetic poles arranged in an outer peripheral portion of the field core 82. As a result, a rotating magnetic field is applied to the stator winding 92 of the stator 9, and an alternating current electromotive force is generated in the stator winding 92.The alternating current electromotive force is supplied to the rectifier 13 via the conductor wire 92a, and rectified in the rectifier 13, and furthermore a quantity thereof is further regulated in the voltage regulator 12, and the alternating current electromotive force is supplied to a battery and an electrical component mounted on a vehicle. Here, the centrifugal fan 1 fixed on the pulley side 7 of the field core 82 rotates due to the rotation of the rotor 8. Due to the rotation of the centrifugal fan 1, external air is admitted into the housing 32 from a portion of an opening formed in the front side housing 31. The external air admitted into the housing 32 flows in the axial direction inside the front side housing 31, reaching the field core 82, and thus cooling the front side coil ends of the field winding 81 and the stator winding 92. Figure 9 is a drawing showing one side of the field core 82 of the rotating electrical machine 100 on which a mounting face G of the centrifugal fan 1 is provided. The mounting face G of the centrifugal fan 1 is provided on a side opposite a side on which extend eight claw-shaped magnetic poles provided on the field core 82. A region F indicated by diagonal lines on Figure 9 indicates a range in which cooling air can be made to circulate during the efficient cooling of the field winding 81, and corresponds to a region where an air gap (or portion) provided between the claw-shaped magnetic poles of the field core 82 is salient on the mounting face G of the centrifugal fan. When the centrifugal fan is attached to the mounting face G, the axial airflow increases due to the overlap of the curved portion Ac and the region F, which extends axially. Conversely, when the curved portion 4c coincides with the mounting face G axially, the airflow collides with the field core 82, and the air cutting noise increases. This means that by arranging the curved portion 4c of the centrifugal fan 1 in a portion overlapping the region F when it protrudes on the mounting face G, an airflow circulating in the axial direction can be made to increase, and the field winding 81 can be cooled efficiently, without causing an increase in the generated air cutting noise. Therefore, the cooling capacity of the coil ends of the field winding 81, the field core 82, and the stator winding 92 can be increased. As a result, the power output of the vehicle-mounted rotating electric machine can be increased. Here, by superimposing the arm-shaped portion 3 of the centrifugal fan 1 onto the mounting face G of the field core 82 and by arranging an erect portion of the blade 4 so as to coincide with an outer edge portion of a claw-shaped magnetic pole of the field core 82, the opening portion which brings cooling air in the axial direction can have a large width.This means that by arranging the flat face portion of the main plate 2 of the centrifugal fan 1 in an axial end portion of the field core 82 of the rotor 8 so that the blade 4 faces an outside side, and furthermore, by arranging the curved portion 4c of the blade 4 so as to overlap in the axial direction an outer edge region of an air gap portion between the claw-shaped magnetic poles configuring the field core 82, or more specifically, at the rear in the direction of rotation of a V-shaped outer edge region, it is possible to efficiently increase airflow in the axial direction, while limiting air-cutting noise. Furthermore, for example, when the maximum outside diameter of the mounting face G of the centrifugal fan 1 is R1, as shown in Figure 9, airflow in the axial direction can be more effectively increased by arranging the curved portion 4c of the centrifugal fan 1 within a range contained within a radius RI (further from one side of the inner diameter than a portion of the maximum outer diameter) from the center of rotation O, the field winding 81 can be efficiently cooled. A region further from the outer side than the radius R1 is a space necessary to allow exhaust air that has cooled the field winding 81 to circulate. Therefore, in order for the air that has cooled the field winding 81 and become hot to be blown outwards in the axial direction, the curved portion 4c of the centrifugal fan 1 must be disposed in a region that does not impede the circulation of exhaust air and that is further from the inner diameter side than RI. By disposing of the curved portion 4c in a region that is further from the inner diameter side than RI, it is possible to improve the cooling properties of the field winding 81, while limiting air cutting noise.In Figure 9, a minimum outside diameter of the mounting face G is shown as R2, and a maximum outside diameter of the field core 82 is shown as RO. In addition, the maximum opening diameter of an intake hole of the crankcase 32 is shown as the outside diameter of the crankcase intake 32r in Figure 9. In the axial direction, a portion of the edge of the intake hole of the crankcase 32 coincides with a circle whose radius is the outside diameter of the crankcase intake 32r. In a plane perpendicular to the axis, the curved portion 4c of the centrifugal fan 1 is provided further on the inner side than the edge portion of the intake hole of the housing 32, i.e. on an inner side of a circle having a radius smaller than the outer diameter of the housing intake 32r, whereby a disturbance of the air circulation occurring at the level of the intake hole of the housing 32 can be kept at a low level, which makes it possible to effectively increase the air circulation in the axial direction and to cool the field winding 81 more effectively, while limiting an air cutting noise. Although the present application is described above in terms of various embodiments and implementation methods given by way of example, it should be understood that the various features, aspects and functions described in one or more of the different embodiments are not limited in their applicability to the particular embodiment with which they are described, but may be applied, alone or in various combinations, to one or more other embodiments. It is therefore understood that many modifications not given as examples can be devised without departing from the scope of this application. For example, at least one constituent component may be modified, added, or removed. At least one of the constituent components mentioned in at least one of the preferred embodiments may be selected and combined with the constituent components mentioned in another preferred embodiment.

Claims

Demands

1. Centrifugal fan (1), comprising a main plate (2) having a multitude of plate-shaped blades (4) arranged in a shape ring in a periphery of an axis of rotation and formed in a range such that a diameter increases from front to back in a direction of rotation, in which the blade (4) is planned to be erected from a portion of the flat face of the main plate (2), at least one of the multitude of blades (4) has a curved portion (4c) in a portion of a portion of a face configuring the blade (4), and a region of the blade (4) in which the curved portion (4c) is provided is inward-facing in the direction of rotation.

2. Centrifugal fan (1) according to claim 1, wherein the curved portion (4c) is provided in a rear edge portion (4b) po- positioned on one side outer diameter of the blade (4).

3. Centrifugal fan (1) according to claim 1, wherein the curved portion (4c) is provided further along one side inner diameter that a portion of the rear edge (4b) positioned on one side diameter outside of the blade (4).

4. Centrifugal fan (1) according to any one of claims 1 to 3, in which a region in which the curved portion is planned (4c) of the blade (4) is provided in a shape such that a radius of curvature decreases when moving in an axial direction from a portion from the tip of the blade (4) towards the flat face portion of the plate main (2).

5. Centrifugal fan (1) according to any one of claims 1 to 3, in which a region in which the curved portion is planned (4c) of the blade (4) is provided in a shape such that a radius of curvature increases when moving in an axial direction from a end portion of the blade (4) towards the flat face portion of the main plate (2).

6. Centrifugal fan (1) according to any one of claims 1 to 5, wherein the curved portion (4c) of the blade (4) is provided from the front backwards in the direction of rotation, and the blade (4) is formed in such a shape that a position in which the radius of curvature in the axial direction is the smallest the approach from the flat face portion of the main plate (2) going forward towards the rear of the blade (4) in the direction of rotation.

7. Centrifugal fan (1) according to any one of claims 1 to 6, in which, when an interval between end portions to the front in the direction of rotation of two adjacent blades (4) is maximal, the curved portion {4c) is provided in the blade (4) positioned at the rear in the direction of rotation.

8. Rotating electrical machine (100) in which the fan centrifugal (1) according to any one of claims 1 to 7 is attached to one end of a rotor (8), in which the flat face portion of the main plate (2) is arranged on a axial end portion of a field core (82) configuring the rotor (8) so that the blade (4) is positioned on a exterior side, and the curved portion (4c) of the blade (4) is arranged so as to coincide in the axial direction with an outer edge region of a portion air gap between claw-shaped magnetic poles configuring the field core (82).

9. Rotating electric machine (100) according to claim 8, in which the curved portion (4c) of the blade (4) is provided further from a on the inner diameter side, a portion of the maximum outer diameter of a mounting face of the field core (82). |Claim 10] Rotating electric machine (100) according to claim 8 or the re- claim 9, in which the curved portion (4c) of the blade (4) is planned further along one side, inner diameter than a portion of the edge from an intake hole of a housing (32) containing the fan centrifugal (1).