JP2021005965A - Rotary electric machine - Google Patents

Abstract

To provide a rotary electric machine to solve a problem in which wind noise increases as a rotational frequency increases in a cooling fan of a rotary electric machine.SOLUTION: The rotary electric machine is stored inside a casing and performs cooling by ventilation from the outside of the casing to the inside of the casing by using the cooling fan fixed, in the form of a ring, to a rotor which rotates synchronizing with a rotating axis. The cooling fan has: a fan blade extending to a rotation axis direction; and a projected part formed by folding an end of the fan blade in the rotation axis direction. Thus, a pressure difference between a rotation direction and a reverse rotation direction of the fan blade is decreased, and suppression of the wind noise is achieved.SELECTED DRAWING: Figure 11

Description

The present application relates to a rotary electric machine.

Vehicle alternators are placed in a limited engine room, so there is a demand for miniaturization. In addition, there is a demand for higher output of AC generators for vehicles due to an increase in the electric load of vehicles due to electrification of in-vehicle devices. Therefore, the output current per unit volume of the AC generator for vehicles tends to increase, and the required cooling capacity is further increased.

For example, in Patent Document 1, in order to improve the cooling efficiency of the AC power generation device for vehicles, the outer diameter tip edge of the blade is moved forward in the rotation direction while having a gap from the blade on the forward side in the rotation direction of the cooling fan. A cooling fan structure has been proposed in which the cooling air that flows in from the inflow port is supplemented and guided to the cooling air flow path.

Further, when the cooling air volume is increased due to an increase in the size of the cooling fan or the number of blades of the cooling fan, the fan noise also increases and the noise inside and outside the vehicle increases. For example, Patent Document 2 describes the cooling fan. A measure to reduce fan noise by devising the blade pitch of the fan is disclosed.

Jikken 8-3169 Gazette Patent No. 6366851

In order to improve the cooling efficiency of the AC power generation device for vehicles, there is a problem that the cooling fan is generally enlarged or the shape of the fan that guides the cooling air flow path is formed, but the wind noise becomes large. Increasing the air volume by the cooling fan and increasing the wind noise leads to a jarring sensation for the user in the vehicle interior.

The AC power generator for vehicles generates electricity by rotating the rotor to which the cooling fan is attached as the engine rotates. As the engine shifts from low speed to high speed, the cooling fan increases the air volume in proportion to the speed, which increases wind noise.

In addition, even if the blade pitch of the cooling fan is devised, the generation of vortices, which are noise sources generated in each blade, is not fundamentally suppressed, so that it is possible to reduce a specific order component. It cannot be expected that the noise level will be reduced enough to push down the overalls.

The present application has been made to solve the above-mentioned problems, and provides a rotary electric machine provided with a cooling fan that significantly improves the quietness of a rotary electric machine such as an AC power generator and suppresses wind noise.

The rotary electric machine disclosed in the present application is housed inside a casing and is cooled by ventilating the inside of the casing from the outside of the casing by a cooling fan ring-fixed to a rotor that rotates in synchronization with the rotating shaft. The cooling fan has a fan blade extending in the direction of the rotation axis, and a protrusion formed by bending the end portion of the fan blade in the rotation axis direction in the rotation direction or the counter-rotation direction, or in the rotation direction and the counter-rotation direction. ..

According to the rotary electric machine disclosed in the present application, the difference pressure between the rotation direction and the counter-rotation direction of the fan blade is reduced by the protrusion formed in the counter-rotation direction, and the noise level can be suppressed.

It is a schematic diagram which roughly described an example of the cross-sectional structure of the rotary electric machine for a vehicle which concerns on Embodiment 1. FIG. It is a perspective view of the rotary electric machine which arranged the plate which suppresses noise in a cooling fan. It is a schematic diagram which roughly described an example of the pressure difference of the cooling air of the cooling fan which concerns on Embodiment 1. FIG. It is a figure which shows an example of the protrusion formed in the cooling fan which concerns on Embodiment 1. FIG. It is a figure which shows another example of the protrusion formed in the cooling fan which concerns on Embodiment 1. FIG. It is a figure explaining the bending angle of the protrusion formed in the cooling fan which concerns on Embodiment 1. FIG. It is a figure explaining the shape of the protrusion formed in the cooling fan which concerns on Embodiment 1. FIG. It is another figure explaining the shape of the protrusion formed in the cooling fan which concerns on Embodiment 1. FIG. It is another figure explaining the shape of the protrusion formed in the cooling fan which concerns on Embodiment 1. FIG. It is another figure explaining the shape of the protrusion formed in the cooling fan which concerns on Embodiment 1. FIG. It is an enlarged view of the part shown by the circle part W of FIG. It is a figure explaining the relationship between the length of the protrusion formed in the cooling fan of Embodiment 1, the ratio of the gap between a cooling fan and a casing, and noise.

Hereinafter, embodiments of the present application will be described in detail with reference to the drawings. The present application is not limited to the embodiments described below. Further, in the drawings described below, the size of each component may differ from the actual device. In addition, the same contents and corresponding parts are designated by the same reference numerals, and detailed description thereof will be omitted.

Embodiment 1.
In the present embodiment, a rotary electric machine for a vehicle will be described as an example. FIG. 1 is a schematic view schematically showing an example of a cross-sectional structure of a rotary electric machine for a vehicle according to the first embodiment. In the rotary electric machine 1 for a vehicle, a rotor 8 fixed to a shaft 6 and a stator 9 surrounding the outer periphery of the rotor 8 with a gap from the rotor 8 are housed in a casing 4. The casing 4 has bearings 5 on both sides of the shaft 6 in the axial direction. The shaft 6 is supported by the bearing 5. The rotor 8 between the bearings 5 on both sides rotates integrally with the shaft 6.

A pulley 7 to which an external driving force is transmitted is fixed to one end of a shaft 6 protruding from the casing 4 by a belt or the like. Further, a pair of slip rings 10 for passing the current of the coil of the rotor 8 are provided at the other end of the shaft 6 on the opposite side. Hereinafter, the side on which the pulley 7 is fixed will be referred to as the front side, and the side on which the slip ring 10 is provided will be referred to as the rear side.

The vehicle rotary electric machine 1 of the first embodiment is a Randell type (also referred to as a claw pole type) rotary electric machine. In the rotor 8, an insulated copper wire is wound in a cylindrical and concentric manner, and a field winding 81 in which an exciting current flows to generate a magnetic flux and a magnetic pole are formed by the generated magnetic flux to form a field winding. It is composed of a field iron core 82 provided so as to cover the wire 81. The field iron core 82 is divided so that the front side and the rear side have different magnetic poles, and each has 6 or 8 claws. The claws of the field iron cores 82 on the front side and the rear side are arranged so as to be alternately displaced at intervals in the rotation direction of the shaft 6. For example, if the front side and the rear side each have 6 claws, the deviation is 30 degrees, if the front side has 8 claws, the deviation is 22.5 degrees, the tip of the front side claw extends to the rear side, and the rear The tip of the claw on the side extends to the front side, and it is arranged in combination.

The stator 9 is arranged so as to surround the rotor 8 with a minute gap, and is wound around a cylindrical stator core 91 and a stator core 91, and is wound in a field as the rotor 8 rotates. It includes a stator coil 92 in which alternating current is generated by a change in magnetic flux from the wire 81.

The casing 4 comprises a front housing 2 and a rear housing 3, which are connected by longitudinal bolts on the outside of the stator 9 in the axial direction of the shaft 6. In the stator 9, the stator core 91 is sandwiched between the open ends of the front housing 2 and the rear housing 3 from both ends in the axial direction. The front side housing 2 and the rear side housing 3 do not cover the entire outer circumference of the stator 9, and an opening is provided so that a part of the outer circumference of the stator 9 is exposed to the outside.

The slip ring 10 is provided on a portion of the shaft 6 protruding from the rear housing 3 to the rear side. The portion of the shaft 6 protruding toward the rear side is covered with the protective cover 27. The protective cover 27 is provided with many openings so that the wind from the outside can flow, and is made of, for example, a grid-like member.

Between the protective cover 27 and the rear housing 3, the brush 11 sliding on the surface of the slip ring 10, the brush holder 17 accommodating the brush 11, and the AC voltage generated by the stator 9 adjacent to the brush 11 A voltage regulator 12 for adjusting the size, a rectifier 13 for rectifying an AC voltage generated by the stator 9 into a DC voltage, and the like are provided.

The lead wire 921 of the stator 9 with the stator coil 92 is pulled out from the rear housing 3 into the protective cover 27 and connected to the terminal of the circuit board 19, and the rectifying device 13 and the stator coil 92 are electrically connected to each other. Be connected. A connector 20 for inputting / outputting signals between the voltage regulator 12 and an external device (not shown) is fixed to the outer periphery of the protective cover 27.

The pulley 7 is fixed to a portion of the shaft 6 protruding from the front housing 2 to the front side. The front side housing 2 has a front bearing storage portion 21A, a bearing 5 is assembled to the front bearing storage portion 21A, a retainer 15 that almost covers the outer ring of the bearing is arranged, and a screw 16 is inserted from the outside of the front side housing 2. It is concluded.

In the vehicle rotary electric machine 1 having the above-described structure, the rotor 8 rotates when the rotation from the engine is transmitted to the pulley 7 via a belt or the like. At this time, by applying an exciting voltage to the field winding 81, each claw portion of the field iron core 82 is excited, a three-phase AC voltage can be generated in the stator coil 92, and the output of the rectifying device 13 is output. A predetermined DC current is taken out from the terminal.

Cooling fans 83 and 84 are configured on the surfaces of the field iron cores 82 on the front side and the rear side opposite to the surfaces having 6 or 8 claws. When the rotary electric machine 1 for a vehicle rotates, cooling air flows in from the rotation axis direction which is the same direction as the shaft 6, and the path is changed in the radial direction by the cooling fans 83 and 84, and the stator 9 and the front housing 2 or the rear side are changed. A cooling air flow path is formed in which cooling air is discharged toward the housing 3. In addition, wind noise is also generated as the cooling fans 83 and 84 rotate.

In order to reduce wind noise, as shown in FIG. 2, a plate 80 separate from the cooling fans 83 and 84 is arranged in the axial direction of the cooling fans 83 and 84, and the air flow path of the cooling air is divided. The above-mentioned wind turbulence can be suppressed and wind noise can be reduced. However, in order to arrange and join the plate 80 separately from the cooling fans 83 and 84, cost or man-hours are required.

Here, the mechanism of wind noise generation will be described. Hereinafter, the cooling fan 83 on the front side will be described as an example, but the cooling fan 84 on the rear side also has the same effect due to the same configuration.

When the cooling fan 83 rotates and guides the cooling air to the air flow path, the fan blade 83a cut up on the housing side of the cooling fan 83, that is, in the direction of the rotation axis and extends from the inner circumference of the rotation shaft to the outer circumference is shown in FIG. 3A. As shown, a pressure difference of the cooling air is generated in the rotation direction and the counter-rotation direction of the fan blade 83a. FIG. 3A is a view of the fan blade 83a of the cooling fan 83 viewed from a direction perpendicular to the rotation axis of the shaft 6. Due to the pressure difference of the cooling air, air wraps around from the side where the pressure is high to the side where the pressure is low (see arrow P in FIG. 3A), and an air vortex is generated. Wind noise is generated by this air vortex.

Therefore, in order to reduce the pressure difference of the cooling air, as shown in FIG. 3B, the tip of the fan blade 83a is bent in the counter-rotation direction of the fan to form the protrusion 85. As a result, the negative pressure in the counter-rotation direction becomes small, and the differential pressure at the end of the fan blade 83a becomes small. As a result, the generated air vortex can be reduced and the noise level can be suppressed.
Further, in order to suppress the wraparound of air, the tip of the fan blade 83a may be bent in the rotation direction of the fan to form the protrusion 85 as shown in FIG. Further, as shown in FIG. 5, the protrusion 85 is not limited to the tip end portion of the fan blade 83a, and may be formed on the entire end portion of the fan blade 83a in which an air vortex is generated. Although FIG. 5 shows an example of bending in the rotation direction, the entire end portion may be bent in the counter-rotation direction.

The bending angle of the tip of the fan blade 83a may be formed by bending parallel to the plane perpendicular to the rotation axis of the shaft 6, that is, at a right angle to the fan blade 83a. This is a shape that is easy to process for the cooling fan 83 that processes the sheet metal by bending it, and the dimensional accuracy can be improved.

Further, as shown in FIG. 6, the angle formed from the surface R perpendicular to the rotation axis of the shaft 6 in the height direction of the protrusion 85 is θ (the suction side is positive). In this case, 0 ° <θ <90 ° may be set. As a result, work by the protrusion 85 can be expected, and the air volume can be increased.

Conversely, it may be set to −90 ° <θ <0 °. As a result, even if an error occurs in the angle of θ, the height of the fan blade 83a hardly changes, so that it is easy to secure a constant air volume.

As shown in FIG. 7A, the shape of the protrusion 85 is such that the surface formed by the bending direction S of the protrusion 85 and the blade chord length direction T of the fan blade 83a is the curved surface of the fan protrusion. When viewed from a direction perpendicular to the curved surface of the fan protrusion, if the shape is a quadrangle (including a substantially quadrangle) as shown by the diagonal line, it is easy to process and the dimensional accuracy of the protrusion 85 can be easily obtained. Further, the effect of suppressing the vortex can be expected over the entire blade chord length direction T having the protrusion 85.

Further, as shown in FIG. 7B, the protrusion 85 has a triangular shape (including a substantially triangular shape), a half ellipse shape as shown in FIG. 7C (including a substantially half ellipse shape), or as shown in FIG. 7D. It may have a quadrilateral shape (including a substantially quadrilateral shape). By making the protrusion 85 into an appropriate shape according to the usage conditions of the cooling fan 83, the ventilation path, the structure of the rotating electric machine for vehicles, or the vortex whose generation location changes depending on the shape of the cooling fan 83, noise can be effectively generated. It can be suppressed.

Further, as shown in FIG. 8, the corner on the inner diameter side of the fan blade 83a of the cooling fan 83 may be chamfered. Alternatively, the inner diameter side may be formed in a circular shape. As a result, the required air volume can be secured and a low-noise cooling fan can be obtained without obstructing the flow of the suction air.

Further, as shown in FIG. 9, the corner of the fan blade 83a of the cooling fan 83 on the outer diameter side may be chamfered. Alternatively, the outer diameter side may be formed in a circular shape. As a result, the protrusion 85 can be provided without increasing the outermost diameter of the cooling fan 83. By suppressing the mass on the outer diameter side of the cooling fan 83, the centrifugal force is reduced, the stress generated in the cooling fan 83 can be reduced, and a highly reliable cooling fan can be obtained.

Further, as shown in FIG. 10, protrusions 85 and 86 may be provided at the tip of the fan blade 83a of the cooling fan 83. By providing a plurality of protrusions on the fan blade 83a having a large vortex generated at the tip, the wind noise reduction effect is increased. In the example of FIG. 10, the protrusions 85 and 86 are provided on opposite sides in the circumferential direction, respectively, but a plurality of protrusions 85 and 86 may be provided in the same circumferential direction.

Further, it is not necessary to form the protrusions 85 on all the fan blades 83a of the cooling fan 83, and the protrusions 85 are formed only on the selected fan blades 83a in order to reduce the noise of a specific frequency. You may. For example, the protrusion 85 may be formed on 10 of the 13 fan blades.

Further, the protrusion 85 may be formed on the side close to the rotation axis of the fan blade 83a extending from the inner circumference in the outer peripheral direction (in the present embodiment, the front side in the rotation direction), and may be formed on the outer peripheral side far from the rotation axis (this implementation). In the form of, it may be formed on the rear side in the rotation direction). This makes it possible to reduce noise caused by the front side or the rear side.

FIG. 11 is an enlarged view of the portion shown by the circle portion W in FIG. FIG. 11B is a view of FIG. 11A viewed from the Y direction. The outermost diameter of the vent hole for intake of the casing 4 and R _i, when the innermost diameter of the protrusion 85 and r _i, may be r _i ≧ R _i. As a result, a sufficient air volume can be secured because the suction flow is not obstructed. Further, when the cooling fan 83 is formed of sheet metal, if the protrusion 85 is provided on the inner diameter side of the fan blade 83a, it may be difficult to configure the developed view, but if it is on the outer diameter side, the developed view is configured. It will be easier.

Further, as shown in FIG. 11, the gap t, which is the clearance between the casing 4 and the fan blade 83a, may be minimized at the protrusion 85. Here, the gap t is a dimension representing a vortex scale generated in the gap between the casing 4 and the protrusion 85. As a result, the vortex can be reduced by reducing the gap between the end portion of the fan blade 83a, which is likely to generate a vortex, and the casing 4. The smaller the vortex, the higher the silent effect.

FIG. 12 is a diagram showing the relationship between the ratio of the length h of the protrusion 85 in the rotation direction and the gap t shown in FIG. 11 and the magnitude of noise. In FIG. 12, when h / t ≧ 1/4, the vortex suppression effect of the leak vortex generated in the gap t can be obtained, and a low noise fan can be realized. In particular, when h / t ≧ 1/2, the vortex suppression effect becomes remarkable, and noise can be further reduced.

The basic vortex scale generated in the fan blade 83a is the height L of the fan blade 83a, and even if the length h of the protrusion 85 in the rotation direction is made larger than the height L of the fan blade 83a, the effect of noise reduction is limited. Therefore, h ≦ L is set to effectively reduce noise.

As described above, the above description has been made by forming the protrusion 85 on the cooling fan 83 on the front side, but the same protrusion as the protrusion 85 may be formed on the cooling fan 84 on the rear side. Further, the protrusion may be formed on one or both of the cooling fan 83 and the cooling fan 84 according to the size of the air vortex generated at the end of the fan blade. As a result, it is possible to reduce the wind noise of all the cooling fans attached to the rotary electric machine.

Although exemplary embodiments are described in the present application, the various features, embodiments, and functions described in the embodiments are not limited to the application of a particular embodiment, either alone or. It can be applied to embodiments in various combinations.
Therefore, innumerable variations not illustrated are envisioned within the scope of the techniques disclosed herein. For example, it is assumed that at least one component is modified, added or omitted.

1: Rotating machine for vehicles 2: Front side housing 3: Rear side housing 4: Casing 5: Bearing, 6: Shaft, 7: Pulley, 8: Rotor, 10: Slip ring, 11: Brush, 12 : Voltage regulator, 13: Slip ring, 17: Brush holder, 19: Circuit board, 20: Connector, 27: Protective cover, 81: Field winding, 82: Field iron core, 83, 84: Cooling fan, 83a : Fan blade, 85, 86: Protrusion, 9: Stator, 91: Stator core, 92: Stator coil, 921: Lead wire

The rotary electric machine disclosed in the present application is housed inside a casing and is cooled by ventilating the inside of the casing from the outside of the casing by a cooling fan ring-fixed to a rotor that rotates in synchronization with the rotating shaft. The cooling fan has a fan blade extending in the rotation axis direction, and a protrusion formed by bending an end portion of the fan blade in the rotation axis direction in a counter- rotation direction or in both a rotation direction and a counter-rotation direction.

Claims (15)

In a rotary electric machine that is housed inside a casing and is annularly fixed to a rotor that rotates in synchronization with a rotating shaft to ventilate and cool the inside of the casing from outside the casing, the cooling fan rotates. A rotary electric machine having a fan blade extending in the axial direction and a protrusion formed by bending an end portion of the fan blade in the rotation axis direction in a rotation direction, a counter-rotation direction, or a rotation direction and a counter-rotation direction. The rotary electric machine according to claim 1, wherein the angle formed by the fan blade and the protrusion is a right angle. The first aspect of the present invention is that the angle formed by the fan blade and the protrusion is between 0 degrees and 90 degrees, where the height direction of the protrusion is positive from a plane perpendicular to the rotation axis. The rotating electric machine described. Claim 1 is characterized in that the angle formed by the fan blade and the protrusion is between 0 degrees and −90 degrees, where the height direction of the protrusion is positive from a plane perpendicular to the rotation axis. The rotary electric machine described in. Claims 1 to 4, wherein the surface formed by the bending direction of the protrusion and the blade chord length direction of the fan blade is a quadrangular shape, a triangular shape, an elliptical shape, a quadrant elliptical shape, or a quadrant elliptical shape. The rotary electric machine according to any one of the items. The rotary electric machine according to any one of claims 1 to 5, wherein the fan blade extends from the inner circumference toward the outer circumference, and the inner peripheral side has a chamfered shape or a circular shape. The rotary electric machine according to any one of claims 1 to 5, wherein the fan blade extends from the inner circumference toward the outer circumference, and the outer peripheral side has a chamfered shape or a circular shape. The rotary electric machine according to any one of claims 1 to 7, wherein the protrusion is formed on a fan blade selected from a plurality of fan blades. The rotary electric machine according to any one of claims 1 to 8, wherein the protrusion is formed on a side of the fan blade extending from the inner circumference toward the outer circumference close to the rotation axis. The rotary electric machine according to any one of claims 1 to 9, wherein the protrusion is formed on the outer peripheral side of the fan blade extending in the outer peripheral direction from the inner circumference and far from the rotation axis. The claim is characterized in that the cooling fans are arranged on the front side and the rear side, and the protrusions are formed on one or both of the front side and the rear side cooling fans. The rotary electric machine according to any one of 1 to 10. The protrusion is arranged outside the ventilation port formed in the casing, and the gap between the protrusion and the casing is the smallest among the gaps in the rotation axis direction between the cooling fan and the casing. The rotary electric machine according to any one of claims 1 to 11, wherein the rotary electric machine is characterized by being present. One of claims 1 to 12, wherein the distance from the rotating shaft to the outer diameter of the ventilation port formed in the casing is equal to or less than the distance from the rotating shaft to the inner diameter of the protrusion. The rotary electric machine described in. The rotary electric machine according to any one of claims 1 to 13, wherein the length of the protrusion in the rotation direction is equal to or less than the height of the fan blade. When the circumferential length of the protrusion is h and the gap between the protrusion and the casing is t,
The rotary electric machine according to any one of claims 1 to 14, wherein h / t ≧ 1/4.

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