JP2010041849A - Rotating electrical machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rotating electrical machine for effectively suppressing a temperature rise of a positive electrode side and negative electrode side diodes. <P>SOLUTION: A cut 30 is formed so that the depth of a groove gradually becomes shallower from the outer diameter end part between adjoining positive electrode side diodes 21, on the surface of a rotor 16 side of a second heatsink base 27, to the inner diameter side. A first rear side air intake hole 3a is drilled on a case 1 so as to face a plurality of heat sink side heat radiation fins 25 in axial direction. A second rear side air intake hole 3b is drilled on the case 1 so as to face in radial direction the outer peripheral surface of a first heat sink base 24. A third rear side air intake hole 3d is drilled on the case 1 so as to face in radial direction the outer diameter side end face of the second heatsink base 27. Further, a bracket side heat radiation fin 3c is extended in radial direction on the outer diameter side of the second rear side air intake hole 3b and on the outer surface of a region 3g of the case 1 to which the second heat sink base 27 is attached, and is arrayed at a predetermined pitch in circumferential direction. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a rotating electrical machine such as a vehicle alternator, and more particularly to a cooling structure for a rectifier.

  In a conventional rectifier in a vehicle AC generator, an arc-shaped positive electrode side and a negative electrode side heat sink having different inner diameters are arranged in a substantially planar shape perpendicular to the shaft, and a plurality of positive electrode side diodes are arranged in a radial direction in the longitudinal direction. A plurality of negative-side diodes are arranged along the circumferential direction on the surface of the positive-side heat sink located on the inner diameter side, and the plurality of negative-side diodes are arranged circumferentially on the surface of the negative-side heat sink located on the outer diameter side with the longitudinal direction facing the circumferential direction. (See, for example, Patent Document 1).

  Here, in the conventional vehicle alternator, the base of the negative-side heat sink is disposed with its back surface in close contact with the inner wall surface of the case, and the base of the positive-side heat sink faces the rotor side, and the negative electrode The inner side of the base of the side heat sink is disposed in a substantially planar shape perpendicular to the shaft. The negative-side diode is cooled by cooling air that flows along the bracket radiating fins standing on the outer surface of the case portion where the base of the negative-side heat sink is in close contact with the rotation of the fan and guided into the case. The On the other hand, the positive-side diode is guided into the case from the portion of the case facing the positive-side heat sink radiating fin, which is erected on the back surface of the positive-side heat sink base by the rotation of the fan, and radiated for the positive-side heat sink Cooling is performed by the cooling air flowing along the fins, and the cooling air flowing radially inward along the bracket radiating fins and guided into the case and flowing along the positive-side heat sink radiating fins.

JP 2000-341919 A

  In conventional vehicular AC generators, the base of the arc-shaped positive-side heat sink is arranged substantially in a plane perpendicular to the shaft, so that the base of the positive-side heat sink is cooled by being sucked from the intake hole by the rotation of the fan. Arranged to block the flow of wind, the ventilation resistance of the ventilation path is large. Further, the cooling air flows inward in the radial direction along the positive-side heat sink radiating fin, and flows between the radiating fin and the shaft toward the rotor. At this time, the ventilation path between a radiation fin and a shaft is narrow, and the ventilation resistance is large. As a result, the amount of cooling air that is guided into the case from the portion of the case facing the positive-side heat sink radiating fin in the axial direction and flows along the positive-side heat sink radiating fin, and the radial direction along the bracket radiating fin The amount of cooling air flowing inward and guided into the case and flowing along the positive-side heat sink radiating fin is limited. Therefore, when the conventional vehicle alternator is applied to an application where high output and miniaturization are desired, the amount of power generation increases, and thus it is necessary to further improve the cooling performance of the positive electrode side and the negative electrode side diode. there were.

  To increase the cooling performance of the positive and negative diodes, increase the heat dissipation area of the positive and negative heat sink fins, or increase the amount of cooling air flowing between the positive and negative heat sink fins. There is a need to. And the heat dissipation area can be increased by increasing the number of positive-side heat sink heat dissipating fins or by increasing the radial length of the positive-side heat sink heat dissipating fins, thereby improving the cooling performance of the positive-side diode. On the other hand, since the radiation fin for brackets is also a strength member, the thickness of the fin cannot be reduced. Therefore, when increasing the number of bracket heat dissipating fins to increase the heat dissipating area, the fin thickness cannot be reduced, so that the gap between the fins is narrowed and the ventilation resistance is increased. Thereby, the air volume of the cooling air flowing along the bracket radiating fin is reduced, and as a result, the cooling performance of the negative electrode side diode cannot be improved.

  The present invention has been made to solve such a problem, and is capable of improving the cooling performance of the first heat sink and the second heat sink and effectively suppressing the temperature rise of the positive side diode and the negative side diode. The purpose is to obtain an electric machine.

The rotating electrical machine according to the present invention is arranged to cover a case, a rotor fixed to a shaft supported by the case and disposed in the case, and supported by the case so as to cover an outer periphery of the rotor. The stator coil is wound around the stator core, and disposed on one side in the axial direction of the rotor in the case, and is electrically connected to the stator coil A rectifier that rectifies alternating current generated in the stator coil into direct current, and a fan that is fixed to one end face in the axial direction of the rotor are provided. The rectifier has a predetermined axial length, a cross section perpendicular to the axial direction is formed in an arcuate cylindrical body, and is disposed substantially coaxially with the shaft, and the first heat sink base, A first heat sink having a plurality of heat sink-side heat dissipating fins extending radially from the inner circumferential surface at a predetermined pitch in the circumferential direction, and an arc-shaped and strip-shaped plate body, A second heat sink having a second heat sink base disposed on the outer diameter side of the first heat sink base and in a substantially planar shape orthogonal to the axis of the shaft and attached in thermal contact with the inner wall surface of the case; A plurality of positive-side diodes mounted on one of the outer peripheral surface of the first heat sink base and the rotor-side surface of the second heat sink base; To has a preparative sink base of the outer peripheral surface and the second heat sink base of the rotor side more negative side diodes mounted on the other surface of the. Then, the groove depth gradually decreases from the outer diameter end portion between the adjacent positive electrode side diode or the negative electrode side diode on the rotor side surface of the second heat sink base toward the inner diameter side. The first intake hole is formed in the case so as to be axially opposed to the plurality of heat sink-side heat dissipating fins, and the second intake hole is opposed to the outer peripheral surface of the first heat sink base in the radial direction. The third intake hole is formed in the case so as to face the outer diameter side end surface of the second heat sink base in the radial direction. Further, the bracket-side radiating fins are radially extended on the outer diameter side of the second air intake hole and on the outer surface of the case region to which the second heat sink base is attached, respectively. They are arranged at a predetermined pitch.

  According to this invention, the cooling air is sucked into the case from the first, second, and third intake holes by the rotation of the fan. The cooling air sucked from the first air intake holes flows between the heat sink side radiating fins and flows to the rotor side. The cooling air sucked from the second air intake hole strikes the outer peripheral surface of the first heat sink base, changes its direction to the axial direction, and flows to the rotor side. The cooling air sucked from the third intake hole flows through the notch and flows to the rotor side.

  The first heat sink base has a predetermined axial length, a cross section perpendicular to the axial direction is formed in an arcuate cylindrical body, and is disposed substantially coaxially with the shaft. There is no hindrance to the axial flow of the cooling air sucked from the holes. Therefore, the ventilation resistance of the ventilation path between the shaft and the first heat sink base is reduced, the flow rate of the cooling air sucked from the first intake hole is increased, and the positive-side diode or negative electrode mounted on the first heat sink base The heat generated by the side diode is effectively dissipated.

  In addition, the bracket-side radiating fin is radially extended on the outer diameter side of the second intake hole and on the outer surface of the case region to which the second heat sink base is attached, and has a predetermined pitch in the circumferential direction. Are arranged in The cooling air flows radially inward along the bracket-side radiation fins and is sucked into the case from the second intake hole. Further, the cooling air flows radially inward along the bracket-side heat radiation fins, is sucked into the case from the third air intake holes, and flows through the notches. Therefore, the flow rate of the cooling air flowing along the bracket-side radiating fin is increased, and the heat generated by the positive-side diode or the negative-side diode mounted on the second heat sink base is effectively radiated. Further, heat generated by the positive diode or the negative diode mounted on the second heat sink base is dissipated to the cooling air flowing through the notch.

  Thereby, the cooling performance of the first heat sink and the second heat sink is improved, and an excessive increase in temperature of the positive diode and the negative diode is suppressed.

Embodiment 1 FIG.
1 is a rear end view showing an automotive alternator according to Embodiment 1 of the present invention, FIG. 2 is a sectional view taken along the line II-II in FIG. 1, and FIG. 3 is according to Embodiment 1 of the present invention. FIG. 4 is a perspective view showing a rectifier in the vehicle alternator according to Embodiment 1 of the present invention, and FIG. 5 is Embodiment 1 of the present invention. FIG. 6 is a perspective view showing a second heat sink applied to the rectifier in the vehicle alternator according to FIG. 6, FIG. 6 is an electric circuit diagram of the vehicle alternator according to Embodiment 1 of the present invention, and FIG. Sectional drawing explaining the structure of the positive electrode side diode applied to the rectifier in the alternating current generator for vehicles which concerns on Embodiment 1 FIG. 8 is applied to the rectifier in the alternating current generator for vehicles which concerns on Embodiment 1 of this invention. Sectional drawing explaining the structure of the negative electrode side diode Figure 9 is a fragmentary sectional view illustrating the flow of cooling air in the automotive alternator according to Embodiment 1 of the present invention schematically.

  1 to 6, an AC generator 100 for a vehicle is supported by a case 1 including a substantially bowl-shaped aluminum front bracket 2 and a rear bracket 3 and a shaft 19 on the case 1 via a bearing 4. The rotor 16 rotatably disposed in the case 1, the pulley 5 fixed to the end of the shaft 19 extending to the front side of the case 1, and the axial end surfaces of the rotor 16. A fixed fan 6, a fixed air gap 10 with respect to the rotor 16, a stator 13 fixed to the case 1 surrounding the outer periphery of the rotor 16, and fixed to the rear side of the shaft 19 The pair of slip rings 7 that supply current to the rotor 16, the pair of brushes 8 that slide on the surface of each slip ring 7, the brush holder 9 that houses these brushes 8, and the stator 13 Contact A rectifier 20 that converts alternating current generated in the stator 13 into direct current, and a voltage regulator that is attached to the heat sink 12 fitted to the brush holder 9 and adjusts the magnitude of the alternating voltage generated in the stator 13. 11.

  The stator 13 includes a cylindrical stator core 14 and a stator coil 15 that is wound around the stator core 14 and generates alternating current due to a change in magnetic flux from the field coil 17 as the rotor rotates. I have.

  The rotor 16 includes a field coil 17 that generates a magnetic flux when an excitation current is passed, a pole core 18 that is provided so as to cover the field coil 17, and a magnetic pole is formed by the magnetic flux, and an axial center position of the pole core 18. And a shaft 19 penetrating therethrough. The fan 6 is fixed to both end surfaces in the axial direction of the pole core 18 by welding or the like.

  The rectifier 20 includes a positive diode 21, a negative diode 22, a first heat sink 23 that supports the positive diode 21, a second heat sink 26 that supports the negative diode 22, positive and negative diodes 21, And a circuit board 28 that electrically connects the stator coil 15 and the stator coil 15.

  As shown in FIG. 7, the positive-side diode 21 includes a rectifying element 21 a configured by pn junction of an N-type semiconductor and a P-type semiconductor, and a surface of the rectifying element 21 a opposite to the P-type semiconductor of the N-type semiconductor. A copper base 21b solder-bonded to the substrate, an insulating resin portion 21c formed by molding the rectifying element 21a and the copper base 21b into a substantially rectangular parallelepiped, and one end connected to the P-type semiconductor of the rectifying element 21a. A lead terminal 21 d is provided that extends from the portion 21 c and has the other end connected to the circuit board 28. As shown in FIG. 8, the negative-side diode 22 includes a rectifying element 22 a configured by pn-junction of an N-type semiconductor and a P-type semiconductor, and a surface of the rectifying element 22 a on the opposite side to the N-type semiconductor A copper base 22b solder-bonded to the substrate, an insulating resin portion 22c molded into a substantially rectangular parallelepiped by molding the rectifying element 22a and the copper base 22b, and one end connected to the N-type semiconductor of the rectifying element 22a. A lead terminal 22d extending from the portion 22c and having the other end connected to the circuit board 28 is provided.

  The first heat sink 23 has a predetermined axial length and a predetermined thickness, and a first heat sink base 24 having a cross section perpendicular to the axial direction formed in an arcuate cylinder, and the first heat sink base 24 A plurality of heat-sink-side heat radiation fins 25 that are erected radially from the inner circumferential surface at a predetermined pitch in the circumferential direction and extend in the axial direction. The positive-side diode 21 is mounted on the outer peripheral surface of the first heat sink base 24 with a predetermined distance in the circumferential direction and a copper base 21b fixed thereto.

  The second heat sink 26 has a second heat sink base 27 having a predetermined thickness and a predetermined radial width, and formed in an arc belt-like plate. The inner diameter of the second heat sink base 27 is made larger than the outer diameter of the first heat sink base 24. The negative diode 22 is mounted on one surface in the thickness direction of the second heat sink base 27 so as to be fixed at a predetermined interval in the circumferential direction so as to fix the copper base 22b. Further, two cutouts 30 are formed at positions between adjacent negative-side diodes 22 on one surface in the thickness direction of the second heat sink base 27 so as to extend from the outer diameter end to the inner diameter side. The bottom surface of each notch 30 is a flat inclined surface whose groove depth gradually decreases from the outer diameter end of the second heat sink base 27 toward the inner diameter side.

  Here, since the first heat sink base 24 is disposed on the inner diameter side of the second heat sink base 27, the area of the outer peripheral surface of the first heat sink base 24 is small, and the positive-side diode 21 is the outer periphery of the first heat sink base 24. It is densely mounted on the surface. On the other hand, since the second heat sink base 27 is disposed on the outer diameter side of the first heat sink base 24, the surface area of the second heat sink base 27 is large, and the negative diode 22 is the outer peripheral surface of the second heat sink base 27. Roughly implemented. In the second heat sink base 27, in order to make the temperature of each of the negative-side diodes 22 uniform, it is necessary to efficiently diffuse the heat, and the thickness is increased. As described above, the first heat sink base 24 and the second heat sink base 27 support the diode and at the same time have the same function of efficiently diffusing the heat generated by the diode. It is for this reason that the thickness of 27 is thicker than the first heat sink base 24.

  A first heat sink 23 surrounds the slip ring 7 together with the brush holder 9 and is disposed and attached in the rear bracket 3 coaxially with the shaft 19. Further, the second heat sink 26 is disposed on the outer diameter side of the first heat sink base 24 and on the rotor 16 side of the first heat sink 23 in a plane perpendicular to the axis of the shaft 19 and coaxial with the shaft 19. The other surface in the thickness direction of the second heat sink base 27 is attached in close contact with the inner wall surface of the rear bracket 3. That is, the second heat sink base 27 is in a thermal contact state with the inner wall surface of the rear bracket 3 and is electrically connected and grounded. The positive-side and negative-side diodes 21 and 22 arranged in this way are two sets of diode bridges by three diode pairs in which a positive-side diode 21 and a negative-side diode 22 are connected in series by a circuit board 28. They are connected to form 20A and 20B.

  The stator coil 15 has a three-phase AC winding 15A made by Y-connecting three windings 15a, 15b, and 15c, and a three-phase made by Y-connecting three windings 15d, 15e, and 15f. An AC winding 15B is configured, and output ends of the windings 15a, 15b, 15c, 15d, 15e, and 15f are connected to a connection point between the positive diode 21 and the negative diode 22 of each diode pair. The three-phase AC voltage output from each output end of the three-phase AC winding 15A is full-wave rectified and output by the diode bridge 20A, and is output from each output end of the three-phase AC winding 15B. The voltage is full-wave rectified by the diode bridge 20B and output.

  Here, the front bracket 2 is formed such that a plurality of front side intake holes 2a are formed in the end surface of the front bracket 2 and the plurality of front side exhaust holes 2b are opposed to the front side coil ends 15f of the stator coil 15 in the radial direction. Has been drilled.

  In addition, a plurality of first rear-side intake holes 3a as first intake holes are formed in an arc shape in the rear bracket 3 so as to be opposed to substantially the entire circumferential direction of the heat-sink-side radiating fins 25 of the first heat sink 23 in the axial direction. The plurality of second rear-side intake holes 3b as second intake holes are provided in the rear bracket 3 so as to be opposed to almost the entire circumferential direction of the outer peripheral surface of the first heat sink base 24 of the first heat sink 23 in the radial direction. The bracket-side radiating fins 3c that are drilled and extend in the radial direction are arranged in the circumferential direction at a predetermined pitch on the outer surface of the region 3g of the rear bracket 3 to which the second heat sink base 27 is attached. A third rear-side intake hole 3d as a third intake hole is formed in the rear bracket 3 so as to be opposed to a substantially entire area in the circumferential direction of the end surface on the outer diameter side of the second heat sink base 27 in the radial direction. 4 Rear side intake holes 3e are formed in the rear bracket 3 so as to face the heat sink 12 for attaching the voltage regulator 11 in the axial direction. A plurality of rear side exhaust holes 3f are formed in the rear bracket 3 so as to face the rear side coil end 15r of the stator coil 15 in the radial direction. At this time, each of the notches 30 is opposed to the third rear side intake hole 3d in the radial direction.

Next, the operation of the vehicle alternator 100 configured as described above will be described.
First, a current is supplied from a battery (not shown) to the field coil 17 of the rotor 16 via the brush 8 and the slip ring 7, and a magnetic flux is generated. By this magnetic flux, the pole core 18 is magnetized alternately into the N pole and the S pole in the circumferential direction.
On the other hand, the rotational torque of the engine is transmitted to the shaft 19 via a belt (not shown) and the pulley 5, and the rotor 16 is rotated. Therefore, a rotating magnetic field is applied to the stator coil 15 of the stator 13, and an electromotive force is generated in the stator coil 15. This alternating electromotive force is rectified into a direct current by the rectifier 20, and the battery is charged or supplied to an electric load.

  The fan 6 is rotated in conjunction with the rotation of the rotor 16. On the front side, the rotation of the fan 6 causes outside air (hereinafter referred to as cooling air) to be sucked into the front bracket 2 from the front side intake hole 2a. The cooling air sucked into the front bracket 2 is bent in the centrifugal direction by the fan 6, cools the front side coil end 15f, and is then exhausted to the outside through the front side exhaust hole 2b.

  On the other hand, on the rear side, the cooling air is sucked into the rear bracket 3 from the first to fourth rear-side intake holes 3a, 3b, 3d, and 3e by the rotation of the fan 6. Then, the cooling air sucked into the rear bracket 3 from the first rear side intake hole 3a flows between the heat sink side heat radiation fins 25 in the axial direction to the rotor 16 as indicated by an arrow A in FIG. Flowing. The cooling air that flows inward in the radial direction along the bracket-side heat radiation fin 3c and is sucked into the rear bracket 3 from the second rear-side intake hole 3b, as shown by an arrow B in FIG. The direction is changed to the axial direction by hitting the outer peripheral surface of 24, and flows to the rotor 16 along the outer peripheral surface of the first heat sink base 24.

  The cooling air that flows inward in the radial direction along the bracket-side radiating fins 3c and is sucked into the rear bracket 3 from the third rear-side intake hole 3d is, as indicated by an arrow C in FIG. And flows to the rotor 16. Further, the cooling air sucked into the rear bracket 3 from the fourth rear side intake hole 3 e circulates radially between the heat radiating fins 12 a of the heat sink 12 and passes between the slip ring 7 and the brush holder 9. And flows to the rotor 16. The cooling air flowing to the rotor 16 is bent in the centrifugal direction by the fan 6, cools the rear side coil end 15r, and is then exhausted to the outside through the rear side exhaust hole 3f.

  Here, in the vehicle alternator 100, the field coil 17, the stator coil 15, the rectifier 20, and the voltage regulator 11 always generate heat during power generation. For example, in a generator with a rated output current of 100 A class, the amount of generated heat is 60 W, 500 W, 120 W, and 6 W at a rotational point that is high in temperature. Excessive temperature rise due to these heat generations deteriorates the performance of the generator and leads to a decrease in the service life of the parts.

  The heat generated by the voltage regulator 11 is radiated to the cooling air flowing between the radiation fins 12a. Heat generated by the positive-side diode 21 of the rectifier 20 is transmitted from the first heat sink base 24 to the heat sink-side radiation fins 25 and radiated to the cooling air flowing between the heat sink-side radiation fins 25. Heat generated in the negative-side diode 22 of the rectifier 20 is transmitted from the second heat sink base 27 to the rear bracket 3 and radiated to the cooling air flowing between the bracket-side heat radiation fins 3c, and the cooling flowing in the notch 30 is performed. Heat is dissipated by the wind. Heat generated by the stator coil 15 is radiated from the front coil end 15f and the rear coil end 15r to the cooling air bent in the centrifugal direction by the fan 6. Further, from the differential pressure between the pressure of the cooling air in the front bracket 2 and the pressure of the cooling air in the rear bracket 3, for example, cooling from the front bracket 2 side through the rotor 16 to the rear bracket 3 side. A wind flow is generated, and heat generated in the field coil 17 is radiated to the cooling air flowing through the rotor 16. Thereby, the heat-generating components built in the case 1 such as the voltage regulator 11, the stator coil 15, the rectifier 20, and the field coil 17 are cooled, and an excessive temperature rise is suppressed.

  According to the first embodiment, the first heat sink 23 has a predetermined axial length, a first heat sink base 24 having a circular cross section perpendicular to the axial direction, and a first heat sink base 24. From the inner peripheral surface of the heat sink base 24, there are a plurality of heat sink-side heat radiation fins 25 that are erected radially at a predetermined pitch in the circumferential direction and extend in the axial direction. The first heat sink 23 is disposed in the rear bracket 3 with the first heat sink base 24 on the outer peripheral side of the slip ring 7 and coaxially with the shaft 19. Further, the first rear-side intake hole 3a is formed in an arc shape in the rear bracket 3 so as to be opposed to substantially the entire circumferential direction of the heat sink-side heat radiation fin 25 in the axial direction.

Therefore, between the slip ring 7 and the first heat sink base 24, heat sink side heat radiation fins 25 that stand from the first heat sink base 24 and extend in the axial direction are arranged at a predetermined pitch in the circumferential direction. Therefore, the ventilation resistance of the ventilation path between the slip ring 7 and the first heat sink base 24 is reduced, and the cooling air flowing through the ventilation path between the heat sink side radiating fins 25 is sucked from the first rear side intake hole 3a. The flow rate increases.
Thereby, the heat generated by the positive-side diode 21 is effectively radiated from the heat sink-side heat radiation fins 25 to the cooling air, and the cooling performance of the positive-side diode 21 is improved. That is, the cooling performance of the first heat sink 23 is improved.

  Further, the second heat sink base 27 is attached in close contact with the inner wall surface of the rear bracket 3 on the outer diameter side of the first heat sink base 24 in a thermal contact state. The notch 30 is located on one surface in the thickness direction of the second heat sink base 27, that is, at a position between the adjacent negative electrode diodes 22 on the surface on the rotor 16 side, and the groove depth is from the outer diameter side of the second heat sink base 27 to the inner diameter. It is formed so as to gradually become shallower on the side. The second rear-side intake hole 3b is formed in the rear bracket 3 so as to be opposed to almost the entire circumferential direction of the outer peripheral surface of the first heat sink base 24 in the radial direction. The bracket-side heat dissipating fins 3c extending in the radial direction are arranged at a predetermined pitch on the outer surface of the region 3g of the rear bracket 3 on the outer diameter side of the second rear-side intake hole 3b and the second heat sink base 27 attached. Arranged in the direction. Further, the third rear-side intake hole 3d is formed in the rear bracket 3 so as to be opposed to the substantially entire area in the circumferential direction of the end surface on the outer diameter side of the second heat sink base 27 in the radial direction.

Therefore, the cooling air flows along the bracket-side radiation fins 3c on the outer surface of the region 3g of the rear bracket 3 to which the second heat sink base 27 is attached, and is sucked into the rear bracket 3 from the second rear-side intake holes 3b. Is done.
Further, since the gap is narrow between the outer diameter side end surface of the second heat sink base 27 and the inner wall surface of the rear bracket 3, when there is no notch 30, the third rear side intake hole 3d is inserted into the rear bracket 3 inside. The amount of cooling air sucked into the air was extremely small. However, the notch 30 is located at a position between the adjacent negative-side diodes 22 on the surface of the second heat sink base 27 on the rotor 16 side, and the groove depth extends from the outer diameter end of the second heat sink base 27 to the inner diameter side. Since it is formed so as to gradually become shallower, the cooling air sucked into the rear bracket 3 from the third rear-side intake hole 3 d flows through the notch 30. Therefore, the flow rate of the cooling air sucked into the rear bracket 3 from the third rear side intake hole 3d is increased, and the amount of cooling air flowing along the bracket side radiating fins 3c is increased.

  As a result, the heat generated in the negative-side diode 22 is radiated to the cooling air flowing along the bracket-side heat radiation fins 3c, and is radiated to the cooling air flowing through the notch 30 of the second heat sink base 27. Coolability is improved. That is, the cooling performance of the second heat sink 26 is improved.

Here, when the output of the vehicle alternator 100 is increased in order to meet the recent demand for higher output, the amount of heat generated by the positive and negative diodes 21 and 22 constituting the rectifier 20 increases. And the crack resulting from thermal fatigue arises in the solder which has joined rectifier 21a, 22a and copper bases 21b, 22b, and the positive electrode side and negative electrode side diodes 21 and 22 will be destroyed worst.
In the present invention, since the cooling performance of the first and second heat sinks 23 and 26 is improved, even if the amount of heat generated in the positive and negative diodes 21 and 22 is increased, the positive and negative diodes 21 and 22 are increased. The heat generated at 22 can be effectively dissipated to the cooling air, and excessive temperature rise of the positive and negative diodes 21 and 22 can be suppressed. Therefore, a situation in which the positive electrode side and negative electrode side diodes 21 and 22 are destroyed can be avoided in advance, and a high-output vehicle alternator 100 can be realized.

  The notch 30 is formed in the second heat sink base 27 so as to face the third rear-side intake hole 3d so that the cooling air sucked from the third rear-side intake hole 3d can efficiently pass therethrough. Is preferred.

  In the first embodiment, the first heat sink base 24 is described as being disposed in the rear bracket 3 coaxially with the shaft 19. However, the first heat sink base 24 is exactly coaxial with the shaft 19. It is not necessary to be disposed on the shaft 19 as long as it is disposed so as to surround the shaft 19 in cooperation with the brush holder 9.

Embodiment 2. FIG.
FIG. 10 is a cross-sectional view of the main part showing the periphery of the rectifier in the automotive alternator according to Embodiment 2 of the present invention.
In FIG. 10, the second heat sink 26 </ b> A is formed such that a notch 30 </ b> A extends from the outer diameter end to the inner diameter side at a position between adjacent negative-side diodes 22 on one surface in the thickness direction of the second heat sink base 27. ing. The bottom surface of the cutout 30 </ b> A has a convex curved surface whose groove depth gradually decreases from the outer diameter end of the second heat sink base 27 toward the inner diameter side.
Other configurations are the same as those in the first embodiment.

  Also in the second embodiment, the notch 30A is formed at a position between the adjacent negative-side diodes 22 on one surface in the thickness direction of the second heat sink base 27 so as to extend from the outer diameter end portion to the inner diameter side. Therefore, the same effect as in the first embodiment can be obtained.

  Further, according to the second embodiment, the bottom surface of the notch 30A is a convex curved surface whose groove depth gradually decreases from the outer diameter end of the second heat sink base 27 toward the inner diameter side. Therefore, the strength reduction of the second heat sink base 27 due to the formation of the notch 30A can be suppressed, and the mechanical strength of the second heat sink 26A can be increased.

  In the second embodiment, the notch 30A is formed as a convex curved surface whose groove depth gradually decreases from the outer diameter end of the second heat sink base 27 toward the inner diameter side. The notch may be formed on the bottom surface where the groove depth becomes shallower stepwise from the outer diameter end of the second heat sink base toward the inner diameter side.

Embodiment 3 FIG.
FIG. 11 is a perspective view showing a second heat sink applied to the rectifier in the automotive alternator according to Embodiment 3 of the present invention.
In FIG. 11, the second heat sink 26 </ b> B has a notch 30 </ b> B in a position between adjacent negative-side diodes 22 on one surface in the thickness direction of the second heat sink base 27 so as to reach from the outer diameter end to the inner diameter side. One by one. The bottom surface of each notch 30B is a flat inclined surface in which the groove depth gradually decreases from the outer diameter end of the second heat sink base 27 toward the inner diameter side.
Other configurations are the same as those in the first embodiment.

  Also in the third embodiment, the notch 30B is formed at a position between adjacent negative-side diodes 22 on one surface in the thickness direction of the second heat sink base 27 so as to extend from the outer diameter end portion to the inner diameter side. Therefore, the same effect as in the first embodiment can be obtained.

  Further, according to the third embodiment, the notch 30B is formed one by one at the position between the adjacent negative-side diodes 22 on one surface in the thickness direction of the second heat sink base 27, so the notch 30B The cross-sectional area of the ventilation path comprised by becomes large. Therefore, the ventilation resistance of the ventilation path that is sucked from the third rear-side intake hole 3d, flows through the notch 30B, and reaches the rotor 16 side is reduced, and the flow rate of the cooling air drawn from the third rear-side intake hole 3d is reduced. The flow rate of the cooling air flowing along the bracket-side heat radiation fins 3c increases, so that the cooling performance of the second heat sink 26B is improved.

Embodiment 4 FIG.
FIG. 12 is a perspective view showing a second heat sink applied to the rectifier in the automotive alternator according to Embodiment 4 of the present invention.
In FIG. 12, the second heat sink 26C has a notch 30C extending from the outer diameter end to the inner diameter end at a position between adjacent negative-side diodes 22 on one surface in the thickness direction of the second heat sink base 27. Two each are formed. The bottom surface of each notch 30C is a flat inclined surface whose groove depth gradually decreases from the outer diameter end portion of the second heat sink base 27 toward the inner diameter end portion.
Other configurations are the same as those in the first embodiment.

  Also in the fourth embodiment, the notch 30C is formed at a position between the adjacent negative electrode side diodes 22 on one surface in the thickness direction of the second heat sink base 27 so as to extend from the outer diameter end portion to the inner diameter end portion. Therefore, the same effect as in the first embodiment can be obtained.

  Further, according to the fourth embodiment, the notch 30C extends from the outer diameter end portion to the inner diameter end portion at a position between the adjacent negative side diodes 22 on one surface in the thickness direction of the second heat sink base 27. Since it is formed, the ventilation resistance of the ventilation path that is sucked from the third rear-side intake hole 3d, flows through the notch 30C, and reaches the rotor 16 side is reduced. Therefore, the flow rate of the cooling air sucked from the third rear-side intake hole 3d is increased, and the flow rate of the cooling air flowing along the bracket-side heat radiation fin 3c is also increased, so that the cooling performance of the second heat sink 26C is improved.

In each of the above embodiments, the vehicle alternator has been described. However, the present invention is not limited to the vehicle alternator, and is applied to rotating electric machines such as a vehicle motor and a vehicle generator motor. Produces the same effect.
In each of the above embodiments, the positive diode is mounted on the first heat sink. However, the negative diode may be mounted on the first heat sink. In this case, the second heat sink on which the positive-side diode is mounted is attached in an electrically insulated state while ensuring a thermal contact state with the rear bracket.

  In each of the above embodiments, the three-phase AC winding is described as being Y-connected. However, even if the three-phase AC winding is Δ-connected, the same effect can be obtained. In each of the above embodiments, six positive side and negative side diodes are mounted on each of the first and second heat sinks. However, the positive electrode mounted on each of the first and second heat sinks. The number of side and negative side diodes is not limited to six. For example, when the stator coil is composed of a set of three-phase AC windings and the output of the three-phase AC windings is full-wave rectified by a diode bridge, the positive electrodes mounted on the first and second heat sinks, respectively. The number of side and negative side diodes is three. Also, when the stator coil is composed of a set of three-phase AC windings, and in addition to the three output terminals of the three-phase AC windings, the output of the neutral point Y-connected is full-wave rectified with a diode bridge. The number of positive side and negative side diodes mounted on each of the first and second heat sinks is four.

In each of the above embodiments, the first heat sink base is made of a cylindrical body having an arc-shaped cross section, but the first heat sink base is not limited to the arc-shaped cross section, The cross-section arc-shaped cylinder having an axial length may be used. For example, a cross-section arc-shaped cylinder in which thin rectangular parallel plates are connected in an arc shape, that is, a cross-section arc-shaped cylinder having a plurality of corners may be used.
Further, in each of the above embodiments, the second heat sink base is assumed to be made of an arc belt-like plate, but the second heat sink base is not limited to the arc shape, and is arc-shaped and belt-shaped. It may be a plate body, and for example, it may be a strip-shaped plate body in which thin rectangular parallel plates are connected in an arc shape, that is, an arc-shaped and strip-shaped plate body having a plurality of corners.

  Further, in each of the above embodiments, the positive electrode side and the negative electrode side diode are formed in a substantially rectangular parallelepiped, but the outer shape of the positive electrode side and the negative electrode side diode is not limited to a substantially rectangular parallelepiped. It may be curved in a body or arc shape.

1 is a rear side end view showing an automotive alternator according to Embodiment 1 of the present invention; It is II-II arrow sectional drawing of FIG. It is the principal part perspective view which looked at the alternating current generator for vehicles concerning Embodiment 1 of this invention from the rear side. It is a perspective view which shows the rectifier in the alternating current generator for vehicles which concerns on Embodiment 1 of this invention. It is a perspective view which shows the 2nd heat sink applied to the rectifier in the alternating current generator for vehicles concerning Embodiment 1 of this invention. It is an electric circuit diagram in the vehicle alternator according to Embodiment 1 of the present invention. It is sectional drawing explaining the structure of the positive electrode side diode applied to the rectifier in the alternating current generator for vehicles concerning Embodiment 1 of this invention. It is sectional drawing explaining the structure of the negative electrode side diode applied to the rectifier in the alternating current generator for vehicles which concerns on Embodiment 1 of this invention. It is principal part sectional drawing which illustrates typically the flow of the cooling wind in the alternating current generator for vehicles which concerns on Embodiment 1 of this invention. It is principal part sectional drawing which shows the surroundings of the rectifier in the alternating current generator for vehicles which concerns on Embodiment 2 of this invention. It is a perspective view which shows the 2nd heat sink applied to the rectifier in the alternating current generator for vehicles concerning Embodiment 3 of this invention. It is a perspective view which shows the 2nd heat sink applied to the rectifier in the alternating current generator for vehicles concerning Embodiment 4 of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Case, 3a 1st rear side intake hole (1st intake hole), 3b 2nd rear side intake hole (2nd intake hole), 3c Bracket side radiation fin, 3d 3rd rear side intake hole (3rd intake hole) , 6 Fan, 13 Stator, 14 Stator core, 15 Stator coil, 16 Rotor, 19 Shaft, 20 Rectifier, 21 Positive side diode, 22 Negative side diode, 23 First heat sink, 24 First heat sink base, 25 Heat sink side radiation fin, 26, 26A, 26B, 26C Second heat sink, 27 Second heat sink base, 30, 30A, 30B, 30C Notch.

Claims (4)

A case, a rotor fixed to a shaft pivotally supported by the case and disposed in the case; a rotor supported by the case and covering the outer periphery of the rotor; The stator wound around the stator core and the alternating current generated in the stator coil disposed on one side in the axial direction of the rotor in the case and electrically connected to the stator coil A rectifier that rectifies the current into a direct current, and a fan that is fixed to an end face on one side in the axial direction of the rotor,
The rectifier has a predetermined axial length, a cross section perpendicular to the axial direction is formed in an arcuate cylindrical body, and is disposed substantially coaxially with the shaft, and the first heat sink base, A first heat sink having a plurality of heat sink-side heat dissipating fins extending radially from the inner circumferential surface at a predetermined pitch in the circumferential direction, and an arc-shaped and strip-shaped plate body, A second heat sink having a second heat sink base disposed on the outer diameter side of the first heat sink base and in a substantially planar shape orthogonal to the axis of the shaft and attached in thermal contact with the inner wall surface of the case; A plurality of positive-side diodes mounted on one of the outer peripheral surface of the first heat sink base and the rotor-side surface of the second heat sink base; It has a preparative sink base of the outer peripheral surface and the second heat sink base of the rotor side more negative side diodes mounted on the other surface of the,
A notch is formed so that the groove depth gradually decreases from the outer diameter end portion between the adjacent positive electrode side diode or the negative electrode side diode on the rotor side surface of the second heat sink base toward the inner diameter side. And
The first intake hole is formed in the case so as to face the plurality of heat sink side heat dissipating fins in the axial direction,
A second air intake hole is formed in the case so as to face the outer peripheral surface of the first heat sink base in a radial direction;
A third intake hole is formed in the case so as to face the outer diameter side end surface of the second heat sink base in a radial direction;
Bracket-side radiating fins are radially extended on the outer diameter side of the second air intake hole and on the outer surface of the case region to which the second heat sink base is attached. A rotating electrical machine characterized by being arranged at a pitch.   The bottom surface of the notch is formed in a convex curved surface whose groove depth gradually decreases from the outer diameter end of the second heat sink base toward the inner diameter side. Rotating electric machine.   The rotating electrical machine according to claim 1 or 2, wherein the notch is formed so as to extend from an outer diameter end portion to an inner diameter end portion of the second heat sink base.   The rotating electrical machine according to any one of claims 1 to 3, wherein the notch is formed so as to be opposed to the third intake hole in a radial direction.

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