JP3785964B2 - AC generator for vehicles - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a vehicle AC generator mounted on a passenger car, a truck, or the like.
[0002]
[Prior art]
Conventionally, in an AC generator for a vehicle, it is generated by preventing water and oil from entering a slip ring formed near one end of a rotating shaft of a rotor and sliding a brush on the slip ring. In order to discharge the abrasion powder of the brush, a brush holder and a slip ring cover assembled through a seal member are used. For example, Japanese Patent Laid-Open No. 9-182353 discloses a vehicle AC generator in which a wear powder discharge hole is formed in a flange portion of a rear frame. In this vehicular AC generator, the brush device is assembled with the labyrinth packing sandwiched between the brush holder and the rear cover, thereby improving the airtightness around the slip ring to prevent foreign matter from entering and sliding the brush on the slip ring. The brush wear powder generated by this is discharged from the wear powder discharge hole.
[0003]
[Problems to be solved by the invention]
By the way, in the conventional vehicle alternator disclosed in the above-mentioned publication, the wear powder discharge hole is only formed in one place. There is a risk that the abrasion powder of the brush may not be discharged. When the wear powder discharge hole is closed, the air flow around the slip ring is blocked, and the temperature of the slip ring and the brush rises. For this reason, since the exciting current of the rotor is reduced and the power generation capacity of the vehicle alternator is reduced, some countermeasure is required.
[0004]
The present invention was created in view of the above points, and an object of the present invention is to provide an automotive alternator capable of reliably discharging brush abrasion powder generated around a slip ring. .
[0005]
[Means for Solving the Problems]
In order to solve the above-described problems, an AC generator for a vehicle according to the present invention has a brush device that houses a brush that slides on a slip ring and covers an outer peripheral portion of the slip ring with a slip ring cover. A first wear powder discharge passage having a first opening that opens in the axial direction of the shaft and a second wear powder discharge passage having a second opening that opens in the radial direction of the rotary shaft are formed. Yes. Providing two types of wear powder discharge passages with different orientations of the openings makes it possible to greatly reduce the probability that these two openings are simultaneously closed. Therefore, the abrasion powder of the brush generated around the slip ring can be reliably discharged through at least one of the openings.
[0006]
In addition, it is desirable to further include a foreign matter intrusion prevention unit that prevents foreign matter from entering the internal space through the first opening around the first opening. Usually, an AC generator for a vehicle is mounted on a vehicle so that the rotation axis is in a horizontal direction, so that the first opening along the rotation axis has a wall surface or the like around it depending on the positional relationship. In some cases, foreign matter such as water may easily enter, but by forming the foreign matter intrusion prevention portion around the first opening, it is possible to effectively prevent such foreign matter from entering.
[0007]
Further, the rotor described above has a cooling fan on the side where the slip ring is formed, and sets the area of the second opening to be smaller than the area of the first opening. It is desirable to form the opening at a position closer to the fan than the first opening. By making the area of the second opening close to the fan and generating a large negative pressure smaller than the area of the first opening, the discharge capacity of the brush wear by the first wear powder discharge passage and the second Since the discharge ability of the brush wear powder by the wear powder discharge passage can be made close or substantially the same, the brush wear powder in the internal space can be discharged in a balanced manner through the two wear powder discharge passages. As a result, the amount of brush wear powder that accumulates in the vicinity of each wear powder discharge passage without being completely discharged can be made substantially the same, and a large amount of undischarged brush wear powder can be found only in one wear powder discharge passage. Accumulation can be prevented.
[0008]
Further, it is desirable that the second opening described above is formed at a position substantially opposite to the top direction when the vehicle is mounted. By disposing the second opening formed in the radial direction on the substantially opposite side (substantially on the ground side) from the top direction, foreign matter can be prevented from entering the internal space through the second opening. . Further, even when foreign matter such as highly viscous mud adheres to the vicinity of the second opening, the foreign matter is shaken off by vibrations of the vehicle alternator itself or vibrations transmitted from the engine. The second opening can be prevented from being blocked.
[0009]
In addition, it is desirable to integrally form the first and second wear powder discharge passages in the frame that holds the rotor described above. The integral molding does not increase the number of parts, and the manufacturing cost, assembly cost, and the like can be reduced.
The second wear powder discharge passage described above is preferably formed at a position offset from the first wear powder discharge passage in the circumferential direction of the rotation shaft. As a result, the probability that the openings of the first and second wear powder discharge passages are simultaneously closed can be further reduced, so that the brush wear powder generated around the slip ring can be more reliably discharged. It becomes possible.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an AC generator for a vehicle according to an embodiment to which the present invention is applied will be described in detail with reference to the drawings.
FIG. 1 is a diagram showing an overall configuration of an automotive alternator. A vehicle alternator 1 shown in FIG. 1 includes a stator 2, a rotor 3, a frame 4, a brush device 5, a rear cover 6, and the like.
[0011]
The stator 2 includes a stator core 22, a three-phase stator winding 23, and an insulator 24 that electrically insulates between the stator core 22 and the stator winding 23.
The rotor 3 has a structure in which a field winding 31 in which an insulated copper wire is wound in a cylindrical and concentric manner is sandwiched from both sides through a rotating shaft 33 by a pole core 32 having six claws. have. A cooling fan 35 for discharging the cooling air sucked from the front side in the axial direction and the radial direction is attached to the end face of the pole core 32 on the front side by welding or the like. Similarly, a cooling fan 36 for discharging the cooling air sucked from the rear side in the radial direction is attached to the end surface of the pole core 32 on the rear side by welding or the like. In addition, two slip rings 37 and 38 that are electrically connected to both ends of the field winding 31 are formed in the vicinity of the rear side end portion of the rotating shaft 33, and the slip rings 37 and 38 are interposed through these slip rings 37 and 38. Then, power is supplied from the brush device 5 to the field winding 31.
[0012]
The frame 4 accommodates the stator 2 and the rotor 3, and is supported in a state where the rotor 3 can rotate around the rotation shaft 33, and a predetermined value is provided on the outer peripheral side of the pole core 32 of the rotor 3. A stator 2 arranged via a gap is fixed. Further, the frame 4 has a cooling air discharge window 42 at a portion facing the stator winding 23 protruding from the axial end surface of the stator core 22, and a suction window 41 at the axial end surface.
[0013]
The brush device 5 includes a brush holder 53 that houses two brushes 51 and 52 that are in sliding contact with the two slip rings 37 and 38, a slip ring cover 54 that covers the outer periphery of the slip rings 37 and 38 together with the brush holder 53, It includes two seal members 55 and 56 which are arranged at the axial ends of the brush holder 53 and the slip ring cover 54 and improve the airtightness of the space formed around the slip rings 37 and 38 when assembled. Yes. These sealing members 55 and 56 are formed of a plate-like rubber material.
[0014]
The rear cover 6 is attached so as to cover the brush device 5, the rectifying device, and the IC regulator that are attached to the outside of the frame 4 on the rear side, and protects these from foreign matters. The rear cover 6 is made of a resin material, and includes a plurality of suction windows formed along concentric circles, three attachment holes through which three bolts 43 attached to the frame 4 pass, and the three And an insert fitting embedded in a region including the mounting hole. The detailed structure of the brush device 5 and the frame 4 and the rear cover 6 in the vicinity thereof will be described later.
[0015]
In the vehicle alternator 1 having the above-described structure, the rotor 3 rotates in a predetermined direction when a rotational force from an engine (not shown) is transmitted to the pulley 20 via a belt or the like. In this state, by applying an excitation voltage from the outside to the field winding 31 of the rotor 3, each claw portion of the pole core 32 is excited, and a three-phase AC voltage can be generated in the stator winding 23. A predetermined direct current is taken out from the output terminal 10.
[0016]
Next, the detailed structure of the brush device 5 and the rear cover 6 will be described. FIG. 2 is a perspective view of the brush device 5 showing the assembled state of the brush holder 53 and the slip ring cover 54. FIG. 3 is a perspective view of the brush holder 53 before the brushes 51 and 52 are assembled, and FIG. 4 is a perspective view of the slip ring cover 54.
[0017]
The brush holder 53 made of a thermosetting resin includes a box portion 152 in which a first storage portion 150 for storing the brushes 51 and 52 and a second storage portion 151 for storing a pigtail are formed. The slip ring 37, 38 side of 152 is a thick portion 153 formed in a concave curved surface shape along the outer peripheral surface of the slip ring 37, 38 in order to increase the surface area. The brush holder 53 is integrally molded by projecting positive and negative terminals 155 made of a metal plate on both end faces 154 along the radial direction of the box portion 152. Further, at both ends in the radial direction of the surface of the thick portion 153 formed in the concave curved surface, a concave portion 156 having a rectangular cross section is formed over the entire length in the axial direction, and the radial direction of the thick portion 153 Two convex portions 157 are formed on both end surfaces along the line.
[0018]
The slip ring cover 54 is for covering and protecting the slip rings 37 and 38 formed on one end side of the rotary shaft 33, and has a shape in which about 1/4 of the circumference of the cylindrical body is removed, The cross-sectional shape in the radial direction is about 3/4 of the circumference. Therefore, the slip ring cover 54 is constituted by a substantially cylindrical peripheral wall 160 made of a resin material (for example, made of nylon) having about 3/4 circle in the circumferential direction. At both ends in the circumferential direction of the peripheral wall 160, relatively thin V-shaped convex portions 161 extending in the axial direction are formed so as to be fitted with the concave portions 156 of the brush holder 53. In addition, a hook-like protrusion 162 that engages with the protrusion 157 of the brush holder 53 is formed outside the V-shaped protrusion 161.
[0019]
The brush device 5 is assembled by fixing the slip ring cover 54 and fitting it into the V-shaped convex portion 161 of the slip ring cover 54 while sliding the concave portion 156 of the brush holder 53. In the brush device 5, the axial lengths of the brush holder 53 and the slip ring cover 54 are set so that no step is generated on both end surfaces in the axial direction in the assembled state. For example, as shown in FIGS. 2 and 3, the end surface on the rear cover 6 side of the box portion 152 and the thick portion 153 of the brush holder 53 and the end surface on the rear cover 6 side of the slip ring cover 54 are on the same plane without steps. Is formed. Further, at least the end surface on the frame 4 side of the thick portion 153 of the brush holder 53 and the end surface on the frame 4 side of the slip ring cover 54 are formed on the same plane without a step.
[0020]
Next, the detailed structure of the rear cover 6 will be described. FIG. 5 is a plan view of the rear cover 6 and shows a shape viewed from the side of the frame 4 in which the brush device 5 and the like are accommodated.
The rear cover 6 has a flat portion 64 formed in a substantially circular shape, and a cylindrical portion 65 extending in the axial direction around the flat portion 64, and on the opening side formed at one end of the cylindrical portion 65. The brush device 5 and the like are accommodated to protect them. A labyrinth structure is formed in the flat surface portion 64 by a groove portion 66 having one or more bent shapes in a region facing the brush device 5 with the seal member 56 interposed therebetween.
[0021]
FIG. 6 is an enlarged view of the vicinity of the region where the maze structure is formed. FIG. 7 is a partial perspective view of the vicinity of the maze structure, and shows the correspondence with the brush device 5 and the like. In FIG. 6, a hatched region 69 is a region covered with the seal member 56, and is surrounded by the groove portion 66 formed in the rear cover 6 and the seal member 56 disposed so as to close the opening of the groove portion 66. A ventilation passage 67 is formed by the space of the maze structure. The ventilation passage 67 connects an internal space sandwiched between the brush holder 53, the slip ring cover 54 and the slip rings 37, 38 and a space inside the rear cover 6 outside the brush device 5. The internal space is kept airtight by the brush device 5 and the two sealing members 55 and 56 disposed on both end surfaces in the axial direction. The rotor 3 is rotated so that the internal space is negatively pressurized. Then, the air sucked from the opening 68 formed at one end of the ventilation passage 67 is guided to the internal space through the ventilation passage 67 and the internal space is ventilated.
[0022]
By the way, the vehicle alternator 1 of the present embodiment is a first formed in a direction along the rotation shaft 33 in order to discharge the air guided into the internal space near the slip rings 37 and 38 described above. And a second opening formed in a direction along the radial direction. Next, these two types of openings will be described in detail.
[0023]
FIG. 8 is a front view showing the outer shape of the frame 4 on the rear side. FIG. 9 is a partially enlarged view of the vicinity of the center of the frame 4 shown in FIG. FIG. 10 is a front view showing the inner shape of the frame 4 on the rear side.
In the rear frame 4, a plurality of suction windows 41 for sucking cooling air into the frame 4 are opened on substantially the same circumference by the rotation of the rear cooling fan 36 fixed to the rotor 3. ing. Further, the box portion 152 of the brush holder 53, the frame 4 side end surface of the thick portion 153, and the frame 4 side end surface of the slip ring cover 54 sandwich the seal member 55 at the rear side end portion of the rear side frame 4. A flange 80 is formed in the contact area. Further, when assembling the brush device 5 adjacent to the flange 80, the negative terminal 155 or the like is secured by screwing it at a position where the negative terminal 155 protruding from the side surface of the brush holder 53 is disposed. A pedestal 82 for electrically connecting and fixing to the frame 4 is formed.
[0024]
In addition, the rear frame 4 has an opening on the rear cover 6 side at a position that is oriented along the rotary shaft 33 and is approximately 90 ° with respect to the sky when the vehicle alternator 1 is assembled to the vehicle. The first wear powder discharge passage 85 having the opened opening 84, and the opening 86 opened in a direction almost opposite to the top direction (substantially the ground direction and accurately deviated by 15 ° with respect to the ground direction). A second wear powder discharge passage 87 is formed. Thus, in the present embodiment, the second wear powder discharge passage 87 is formed at a position offset in the circumferential direction of the rotary shaft 33 from the position of the first wear powder discharge passage 85.
[0025]
FIG. 11 is an enlarged cross-sectional view including one wear powder discharge passage 85 having an opening 84 in the direction along the rotation axis 33, which is a cross-section including the O-XI line shown in FIG. A state in which the rear cover 6 and the like are assembled is shown. In FIG. 11, dotted arrows indicate the flow of air that is sucked into the internal space near the slip rings 37 and 38 and discharged through the wear powder discharge passage 85.
[0026]
The opening portion 84 of the wear powder discharge passage 85 is divided into three substantially the same size, and an outer wall portion 88 as a convex foreign matter intrusion prevention portion is formed so as to surround them. The outer wall portion 88 is for preventing foreign matter from entering along the rear end face of the rear frame 4 and the slip ring cover 54 from at least the top direction, and is provided around the opening 84 and in the top direction. And a range facing the slip ring cover 54.
[0027]
12 is an enlarged cross-sectional view including the other wear powder discharge passage 87 having an opening 86 in the radial direction, and is a cross-section including the O-XII line shown in FIG. A state in which 6 etc. are assembled is shown. In FIG. 12, dotted arrows indicate the flow of air that is sucked into the internal space near the slip rings 37 and 38 and discharged through the wear powder discharge passage 87.
[0028]
The wear powder discharge passage 87 is configured by closing a groove portion (concave portion) formed along a radial direction in a part of the inner end portion of the frame 4 on the rear side by disposing a bearing 89 on the opening side thereof. Yes. The opening 86 of the wear powder discharge passage 87 has an area set to about 1/3 of the opening 84 of the wear powder discharge passage 85 described above. Further, the opening 86 of the wear powder discharge passage 87 is formed at a position closer to the cooling fan 36 on the rear side than the opening 84 of the wear powder discharge passage 85 described above, and when the cooling fan 36 is rotated. The negative pressure generated in is set so as to be larger in the vicinity of the opening 86 having a smaller area than in the vicinity of the opening 84 having a larger area.
[0029]
As described above, in the vehicle alternator 1 according to the present embodiment, the two kinds of wear powder discharge passages 85 and 87 having different opening directions are formed, and therefore foreign matter such as muddy water has entered the rear cover 6. In some cases, the probability of these two openings 84, 86 being simultaneously closed can be greatly reduced. Therefore, the brush wear powder generated around the slip rings 37 and 38 can be reliably discharged through at least one of the openings. In particular, since an outer wall portion 88 as a foreign matter intrusion prevention portion is formed around one opening portion 84 along the rotation shaft 33, the outer side surface of the rear frame 4 and the outer peripheral surface of the slip ring cover 54 are formed. It is possible to effectively prevent foreign matter from entering the opening 84 along the line.
[0030]
In addition, by making the area of the opening 86 close to the rear cooling fan 36 along the radial direction where a large negative pressure is generated smaller than the area of the opening 84 along the rotation shaft 33, The discharge capacity of the brush wear by the connected wear powder discharge passage 87 and the discharge capacity of the brush wear powder by the wear powder discharge passage 85 connected to the opening 84 can be set close to or substantially the same. The brush wear powder can be discharged in a balanced manner through the two wear powder discharge passages 85 and 87. As a result, the amount of brush wear powder deposited without being completely discharged in the vicinity of the respective wear powder discharge passages 85 and 87 can be made substantially the same, and the brush wear powder that has not been discharged only in one of the wear powder discharge passages. Can be prevented from being concentrated and deposited.
[0031]
Further, by disposing the radial opening 86 on the substantially opposite side (substantially the ground direction) from the top direction, it is possible to prevent foreign matter from entering the internal space through the opening 86. Moreover, even when a foreign matter such as highly viscous mud adheres to the vicinity of the opening 86, the foreign matter is easily shaken off by the vibration of the vehicle alternator 1 itself or the vibration transmitted from the engine. It is possible to prevent 86 from being blocked.
[0032]
Further, by integrally forming the above-described wear powder discharge passages 85 and 87 as a part of the frame 4, the number of parts can be reduced, so that the manufacturing cost, the assembling cost and the like can be reduced.
In addition, since the two openings 84 and 86 are formed, it is easy to increase the area of the entire opening compared to the conventional case, and the brush temperature is reduced by increasing the discharge capacity of air and brush wear powder. be able to.
[0033]
In addition, by offsetting the formation position of the second wear powder discharge passage 87 from the formation position of the first wear powder discharge passage 85 in the circumferential direction of the rotary shaft 33, that is, by shifting along the radial direction, The probability that the openings of the two types of wear powder discharge passages 85 and 87 are simultaneously closed can be further reduced.
[Brief description of the drawings]
FIG. 1 is a diagram showing an overall configuration of an automotive alternator.
FIG. 2 is a perspective view of the brush device showing an assembled state of the brush holder and the slip ring cover.
FIG. 3 is a perspective view of a brush holder before a brush is assembled.
FIG. 4 is a perspective view of a slip ring cover.
FIG. 5 is a plan view seen from the inside of the rear cover.
FIG. 6 is a partially enlarged view of a rear cover in the vicinity of a region where a maze structure is formed.
FIG. 7 is a partial perspective view of the vicinity of the maze structure.
FIG. 8 is a front view showing an outer shape of a rear frame.
9 is a partial enlarged view of the vicinity of the center of the frame shown in FIG. 8. FIG.
FIG. 10 is a front view showing the inner shape of the rear frame.
FIG. 11 is an enlarged cross-sectional view including one wear powder discharge passage having an opening in a direction along the rotation axis.
FIG. 12 is an enlarged cross-sectional view including the other wear powder discharge passage having an opening in the radial direction.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Vehicle AC generator 2 Stator 3 Rotor 4 Frame 5 Brush device 6 Rear cover 37, 38 Slip ring 51, 52 Brush 53 Brush holder 54 Slip ring cover 55, 56 Seal member 80 Flange 84 Opening (axial direction)
85 Wear powder discharge passage (axial direction)
86 Opening (radial direction)
87 Wear powder discharge passage (radial direction)
88 Exterior wall

Claims (6)

In a vehicle AC generator having a brush device that houses a brush that slides on a slip ring provided on a rotating shaft of a rotor and covers an outer peripheral portion of the slip ring with a slip ring cover,
A ventilation passage that guides the sucked air to an internal space formed by the slip ring cover;
A first opening that opens in an axial direction of the rotating shaft, and discharges abrasion powder generated by sliding between the slip ring and the brush to the outside from an internal space formed by the slip ring cover. 1 wear powder discharge passage,
A second opening that opens in a radial direction of the rotating shaft, and discharges abrasion powder generated by sliding between the slip ring and the brush from an internal space formed by the slip ring cover to the outside. 2 wear powder discharge passages,
A vehicle alternator characterized by comprising: In claim 1,
An AC generator for a vehicle, comprising a foreign matter intrusion prevention portion for preventing foreign matter from entering the internal space through the first opening portion around the first opening portion. In claim 1 or 2,
The rotor has a cooling fan on the side where the slip ring is formed,
The area of the second opening is set smaller than the area of the first opening, and the second opening is formed at a position closer to the fan than the first opening. AC generator for vehicles. In any one of Claims 1-3,
The vehicular AC generator is characterized in that the second opening is formed at a position substantially opposite to the sky when mounted on the vehicle. In any one of Claims 1-4,
A frame for holding the rotor;
An AC generator for a vehicle, wherein the first wear powder discharge passage and the second wear powder discharge passage are integrally formed in the frame. In any one of Claims 1-5,
The AC power generator for vehicles, wherein the second wear powder discharge passage is formed at a position offset from the first wear powder discharge passage in a circumferential direction of the rotary shaft.

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