JP2002233103A - Rotating electric machine for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotating electric machine for a vehicle which can suppress noise by reducing the transmission of vibration from a stator to a frame. SOLUTION: An AC generator 1 for a vehicle is constituted by including the stator 2 having protruded parts 22a, 22b, 22c, and 22d in four parts in an external peripheral part and a drive frame 6 having a bolt mounting part 10, so as to make it conform to these protruded parts. A stator core 21 of the stator 2, by generating high strength in the four-part protruded pats and low strength in a recessed part except the protruded parts, is vibrated so as to make each protruded part serve as a node for vibration and the recessed part between the protruded parts serve as a loop of vibration. The stator 2, coming into contact with the internal peripheral surface of the drive frame 6 in the four-part protruded parts 22a and the like, is tightened by a tightening bolt 10, so as to make the transmission difficult to the drive frame 6 of vibration generated in the stator 2, the generation of magnetic noise can be suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotating electric machine for a vehicle such as an AC generator for a vehicle mounted on a passenger car or a truck.

[0002]

2. Description of the Related Art In recent years, there has been a remarkable demand for lowering noise of vehicle parts due to a demand for quieter vehicles. In particular, in an automotive alternator, it is urgently necessary to reduce magnetic noise generated during power generation as one of the causes of noise generation. This magnetic noise is generated when a load current flows through the armature winding, and the magnetic flux in the air gap changes due to the armature reaction, and the Lorentz force that fluctuates with this changes the rotor and the stator. It is known that this occurs when the stator, the frame, and the like vibrate when acting as a vibrating force during the period. The generation of this magnetic sound is difficult to avoid due to the power generation function.

[0003] In addition, engine noise has been increasingly reduced in recent years due to social demands for reducing noise outside the vehicle and the aim of improving the productiveness by improving the quietness of the vehicle interior. In such a situation, fan noise and magnetic noise of the AC generator are likely to be heard by a driver or the like.

FIG. 8 is a longitudinal sectional view showing a general structure of a conventional automotive alternator. When the fastening bolt 100 is tightened, the stator 106 is held between the drive frame 102 and the rear frame 104.

FIG. 9 is a diagram showing a vibration mode of the drive frame 102 when a magnetic sound is generated. As shown in FIG. 9, it can be seen that the stator 106 and the drive frame 102 are integrally vibrating in an annular mode (secondary mode) with axes of symmetry I and II orthogonal to each other.
M1 is the drive frame 10 at any moment.
2 shows the vibration mode state, and N1 shows the vibration mode state of the stator 106 at the same moment. It can be seen that the vibration levels and phases of the drive frame 102 and the stator 106 are almost the same. Also, M
2 has a phase of 1 with respect to the vibration mode state indicated by M1.
This shows another vibration mode state in a state advanced by 80 degrees. In any of the vibration mode states, the exciting force that causes the vibration is Lorentz force, and when the stator 106 vibrates in the circular mode, the drive frame 102 integrated with the stator 106 also has a circular shape. Vibrating in mode.

[0006]

As shown in FIG. 9, a conventional vehicle alternator has a fastening bolt 1
00, the bolt mounting portions 102a to 102d of the drive frame 102 serve as nodes of vibration, and the stay portion 102e serves as an antinode of vibration. The stay portion 10e is located at a position where the amplitude of vibration generated in the drive frame 102 is maximum.
Since 2e is formed, there is a problem that the amount of vibration transmitted to the vehicle becomes very large, and the magnetic noise increases accordingly.

Conventional techniques for reducing magnetic noise include Japanese Patent Publication No. 63-49467 and Japanese Patent Laid-Open No. 5-566.
No. 15, JP-A-8-70554 and the like are known, but none of these methods focuses on the state of transmission of vibration, but by devising the state of transmission of vibration. It is expected that noise can be further reduced.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to reduce the transmission of vibration from a stator to a frame, thereby suppressing noise in a vehicular rotating electric machine. Is to provide.

[0009]

In order to solve the above-mentioned problems, a rotating electric machine for a vehicle according to the present invention includes a rotor for generating a rotating magnetic field, a stator core disposed outside the rotor, and a stator core. The stator includes a stator having a stator winding mounted on a child core, and a frame supporting the rotor and the stator. This frame has a plurality of bolt mounting portions for mounting fastening bolts for fixing the stator core, and at positions other than these bolt mounting portions, the outer peripheral surface of the stator core and the opposing surface on the inner peripheral side of the frame. Is formed between them. By forming a gap between the frame and the stator and at a position other than the bolt attachment portion, when a vibration node is located near the bolt attachment portion and a vibration antinode is located at other positions, respectively. Since the vibration of the stator becomes difficult to be transmitted to the frame side due to the presence of the gap, the generation of loud noise can be suppressed.

[0010] In particular, the above-described stator core has a first projection at a position corresponding to the bolt mounting portion.
It is desirable to make the protrusions of the above contact the inner peripheral surface of the frame. Alternatively, the above-described frame has a second convex portion at an inner peripheral surface facing the outer peripheral surface of the stator and corresponding to the bolt attachment portion. Is desirably in contact with the outer peripheral surface. The first protrusion or the second protrusion serves as a node of vibration, and since the stator contacts the frame at this portion, it becomes difficult for the vibration to be transmitted from the stator to the frame, thereby suppressing generation of noise. it can.

Further, the above-mentioned frame has a stay portion for mounting the vehicle, and it is desirable that the position of the stay portion and the position of the bolt mounting portion be matched. As a result, the vibration transmitted to the vehicle side can be suppressed as much as possible, and the generation of noise can be further suppressed.

It is desirable that an elastic body be interposed in the above-mentioned gap. With this elastic body, the vibration of the stator can be attenuated, and the radiated sound emitted from the stator core surface exposed in the gap can also be reduced.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A vehicle AC generator according to an embodiment of the present invention will be described below in detail with reference to the drawings.

[First Embodiment] FIG. 1 is a sectional view showing the overall configuration of an automotive alternator according to a first embodiment.
An AC generator 1 for a vehicle shown in FIG. 1 includes a stator 2, a rotor 3, a brush device 4, a rectifying device 5, a drive frame 6,
It includes a rear frame 7, a rear cover 8, a pulley 9, and the like.

The stator 2 includes a stator core 21 and three-phase stator windings 23 wound at predetermined intervals around a plurality of slots formed in the stator core 21.

The rotor 3 has a field winding 31 formed by winding an insulated copper wire in a cylindrical and concentric manner, each of which has a length of 6 mm.
The rotation axis 33 is provided by the pole core 32 having the claw portions.
Has a structure sandwiched from both sides. Also,
An axial cooling fan 34 is attached to the end face of the pole core 32 on the front side by welding or the like to discharge the cooling air sucked from the front side in the axial direction and the radial direction. Similarly, a centrifugal cooling fan 35 is attached to the end face of the rear pole core 32 by welding or the like to discharge the cooling air sucked from the rear side in the radial direction.

The brush device 4 is composed of the rectifier 5 and the rotor 3
And a slip ring 36 formed on the rotating shaft 33 of the rotor 3.
37 are provided with brushes 41 and 42 for pressing the respective brushes.
The rectifier 5 rectifies a three-phase AC voltage, which is an output voltage of the three-phase stator winding 23, to obtain DC output power.

Drive frame 6 and rear frame 7
Houses the stator 2 and the rotor 3, and the rotor 3
Are supported so as to be rotatable about a rotation shaft 33, and the stator 2 disposed on the outer peripheral side of the pole core 32 of the rotor 3 via a predetermined gap is fixed. The drive frame 6 has a cylindrical portion 61 and a side wall portion 62 integrally formed by aluminum die casting. The stator core 21 is press-fitted into the inner diameter side of the cylindrical portion 61, thereby fixing the stator 2. A bearing 63 is held in the center of the side wall 62, and the bearing 63 supports one end of the rotor 3.
Similarly, the rear frame 7 has a cylindrical portion 71 and a side wall portion 72 integrally formed by aluminum die casting. A bearing 73 attached to the rear side of the rotor 3 is accommodated in the center of the side wall portion 72, and thereby the other end side of the rotor 3 is supported.

The drive frame 6 and the rear frame 7 are fastened by a plurality (for example, four) of fastening bolts 10. These fastening bolts 10 are also used for fixing the stator 2 in the drive frame 6. The drive frame 6 has a bolt mounting portion 66 in which a female screw groove is formed for tightening the four fastening bolts 10. The bolt attachment portion 66 is formed by projecting the cylindrical portion 61 outward in the radial direction, and has high strength by being thicker than other portions of the cylindrical portion 61.

Further, stay portions 64 and 65 are formed on the drive frame 6 so as to protrude radially outward, and a stay portion 74 is formed on the rear frame 7 so as to protrude radially outward. ing. Attachment to a vehicle is performed using these stay portions 64, 65, 74.

The rear cover 8 covers the whole of the brush device 4, the rectifying device 5, and the IC regulator 11 attached to the outside of the rear frame 7, and protects them.

Vehicle alternator 1 having the above-described structure
Is connected to the pulley 9 via a belt or the like by an engine (not shown).
When the rotational force is transmitted, the rotor 3 rotates in a predetermined direction. In this state, by applying an excitation voltage to the field winding 31 of the rotor 3 from the outside, each claw of the pole core 32 is excited, and a three-phase AC voltage can be generated in the stator winding 23. The DC output power is taken out from the output terminal of the rectifier 5.

Next, the drive frame 6 and the stator core 2
1 will be described in detail.

FIG. 2 is a sectional view taken along the line II-II of FIG.
Among them, the rotor 3 and its peripheral parts are omitted. FIG. 3 is a diagram showing only the stator core 21.

As shown in FIGS. 2 and 3, the stator core 21 of this embodiment has four convex portions 22a, 22b, 22c, 22d at 90-degree intervals on the outer peripheral side. That is, the thickness of the stator core 21 in the radial direction is greater at the position of the protrusion 22a and the like than at other portions. For this reason, the stator 2 has a difference in strength along the circumferential direction. The protrusions 22 a and the like having high strength are located at nodes of vibration, and the recesses sandwiched between two adjacent protrusions are antinodes of vibration. And oscillates in an annular mode (secondary mode) with axes of symmetry I and II orthogonal to each other. In FIG. 3, M1 is a vibration mode state at an arbitrary moment, and M2 has a phase of 18 from the state of M1.
This shows a vibration mode state advanced by 0 degrees.

Further, as shown in FIG.
The positions of the four protrusions 22a, 22b, 22c, and 22d coincide with the positions of the four bolt attachment portions 66 formed on the drive frame 6, and at these positions, the stator 2 and the drive frame 6 Contact. Therefore, the stator 2 is fixed in contact with the drive frame 6 at a position serving as a node of the vibration, and the vibration is not easily transmitted through the contact portion. Moreover, since the formation position of the one stay portion 64 of the drive frame 6 coincides with the formation position of the bolt attachment portion 66, the vibration transmitted to the stay portion 64 is suppressed as much as possible, and the vibration is hardly transmitted to the vehicle side. Therefore, generation of magnetic noise can be further suppressed.

FIG. 4 is a diagram showing a vibration mode of the drive frame 6 assembled to the vehicle alternator 1.
In FIG. 4, the vibration level is indicated by the degree of distortion of the ellipse, and indicates that the vibration level decreases as the ellipse approaches a circle. In other words, the symmetry axes I and II in the vibration mode state are the same in the drive frame 6 and the stator 2 and are not changed, but since the vibration is hardly transmitted from the stator 2 to the drive frame 6, the drive frame 6 It can be seen that the level of its own vibration has been greatly reduced.

FIG. 5 shows a vehicle alternator 1 according to this embodiment.
FIG. 6 is a diagram showing the result of measuring the magnetic sound of FIG. The vertical axis indicates the sound pressure level of the magnetic sound in dB, and the horizontal axis indicates the rotation speed. The characteristic shown by the solid line indicates the magnetic sound of the vehicle alternator 1 of the present embodiment. The characteristics shown by the dotted lines indicate the magnetic sound of the conventional vehicle alternator. As shown in FIG. 5, in the vehicle alternator 1 of the present embodiment, it can be seen that the magnetic sound is significantly suppressed as compared with the conventional product.

[Second Embodiment] FIG. 6 is a cross-sectional view of an automotive alternator according to a second embodiment, and shows a structure corresponding to FIG. The vehicle alternator 1A according to the present embodiment uses a stator 2A having no irregularities on the outer peripheral portion with respect to the vehicle alternator 1 according to the first embodiment,
At the position where the bolt attachment portion 66 is formed, the cylindrical portion 61
Is different in that a drive frame 6A having four convex portions 67 on the inner peripheral side is used. These four convex portions 6
7 can be formed by removing the other inner peripheral surface of the cylindrical portion 61 by cutting or the like.

The four convex portions 67 of the drive frame 6A
In a state where the stator 2A is press-fitted on the inner peripheral side and the stator 2A is tightened by the fastening bolt 10, the vicinity of the bolt mounting portion 66 and the convex portion 67 becomes a node of vibration, and the adjacent bolt mounting portion 66 Near the middle is the antinode of the vibration.
As described above, the vibration mode state of the drive frame 6A corresponds to the drive frame 6 of the first embodiment shown in FIG.
Is the same as Therefore, the vibration generated by the stator 2A is less likely to be transmitted to the drive frame 6A that is in contact with the stator 2A at the position of the node of the vibration, and it is possible to suppress the magnetic noise of the vehicle AC generator 1A. .

Third Embodiment FIG. 7 is a cross-sectional view of a vehicle alternator according to a third embodiment, and shows a structure corresponding to FIG. The vehicle alternator 1B according to the present embodiment is different from the vehicle alternator 1 according to the first embodiment in that a concave portion (a portion other than the convex portion 22a) of the outer periphery of the stator 2 is provided.
A different point is that a gap formed between the inner peripheral surface of the cylindrical portion 61 of the drive frame 6B is filled with the elastic body 25. By filling the elastic body 25, the stator 2
Vibration can be attenuated, the radiation sound emitted from the surface of the stator core 21 can be reduced, and the magnetic sound can be suppressed in a complex manner. In addition, by using the elastic body 25 having good thermal conductivity,
The cooling performance of the stator 2 can also be improved.

The present invention is not limited to the above embodiment, and various modifications can be made within the scope of the present invention. For example, in the above-described third embodiment, the elastic body 25 is filled in the gap formed between the stator 2 and the drive frame 6 in the vehicle alternator 1 of the first embodiment. In the vehicle alternator 1A of the second embodiment, the elastic body 25 may be filled in a gap formed between the stator 2A and the drive frame 6A.

Further, in the above-described embodiment, the vehicle alternator has been described. However, when the vehicle has a similar structure in which the stator is supported by the frame, the present invention is applied to a vehicle rotating electric machine other than the vehicle AC generator. The invention can be applied.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating an overall configuration of a vehicle alternator according to a first embodiment.

FIG. 2 is a sectional view taken along line II-II of FIG.

FIG. 3 is a view showing a stator core.

FIG. 4 is a diagram showing a vibration mode of a drive frame assembled to the vehicle alternator.

FIG. 5 is a diagram showing a result of measuring a magnetic sound of the automotive alternator of the present embodiment.

FIG. 6 is a cross-sectional view of a vehicle alternator according to a second embodiment.

FIG. 7 is a cross-sectional view of a vehicle alternator according to a third embodiment.

FIG. 8 is a longitudinal sectional view showing a general configuration of a conventional vehicle alternator.

FIG. 9 is a diagram illustrating a vibration mode of a drive frame when a magnetic sound is generated.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Vehicle alternator 2 Stator 3 Rotor 4 Brush device 5 Rectifier 6 Drive frame 7 Rear frame 10 Fastening bolt 21 Stator iron core 22a, 22b, 22c, 22d Convex part 61, 71 Cylindrical part 62, 72 Side wall part 66 Bolt mounting part

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Masao Ichikawa 1-1-1 Showa-cho, Kariya-shi, Aichi F-term in DENSO Corporation (Reference) 5H002 AA04 AB01 AB04 AB06 AC03 AE07 AE08 5H605 AA04 AA05 BB03 CC01 CC03 CC10 EA01 EA09 GG06 GG16 5H619 AA03 AA10 BB02 BB06 BB17 PP01 PP04 PP10

Claims (5)

[Claims] A stator for generating a rotating magnetic field; a stator having a stator core disposed outside the rotor and a stator winding provided on the stator core; In a rotating electrical machine for a vehicle having a frame supporting a stator, the frame has a plurality of bolt attachment portions for attaching fastening bolts for fixing the stator core, and at a position other than these bolt attachment portions, A rotating electrical machine for a vehicle, wherein a gap is formed between an outer peripheral surface of the stator core and an opposing surface on an inner peripheral side of the frame. 2. The stator core according to claim 1, wherein the stator core has a first protrusion at a position corresponding to the bolt mounting portion, and the first protrusion is provided on an inner peripheral surface of the frame. A rotating electric machine for a vehicle, which is in contact with the rotating electric machine. 3. The frame according to claim 1, wherein the frame has a second convex portion at an inner peripheral surface facing an outer peripheral surface of the stator and at a position corresponding to the bolt attachment portion. A rotating electric machine for a vehicle, wherein the second convex portion contacts an outer peripheral surface of the stator. 4. The frame according to claim 1, wherein the frame has a vehicle mounting stay.
A rotating electric machine for a vehicle, wherein the position of the stay portion and the position of the bolt mounting portion are matched. 5. The rotating electric machine for a vehicle according to claim 1, wherein an elastic body is interposed in the gap.