JP2652633B2 - AC generator for vehicles - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automotive alternator in which a rectifier is fixed to a bracket so as to be able to conduct heat, and in particular, a cooling fin of the rectifier of an automotive alternator. To improve the cooling capacity.

2. Description of the Related Art The required output of an automotive alternator has been steadily increasing in order to improve the safe driving and comfort of the automobile. The spread of cars has caused traffic congestion in cities,
For this reason, when the car is idle and stopped,
In some cases it can be as much as 30% of the total operating time. From these two points, there is a demand for an automotive alternator that starts charging at an extremely low speed and has a large output. Satisfying such demands will increase the weight and shape of the automotive alternator. Therefore, miniaturization and high output of the automotive alternator are social demands, and accordingly, the rectifier of the automotive alternator must be miniaturized and increased in output.

However, since it is not easy to reduce the forward voltage drop of the diode, there is a problem that the life of the diode is shortened due to an increase in heat generated by the rectifier. As a countermeasure, the rectifier device to cool the, as shown in Figure 9 and Figure 10, a substantially horseshoe shape first plurality of the side surfaces of the cooling fins F ₁ -
Place a negative diode D _1, the first cooling fin F ₁ and the average radius of the plurality of side surfaces of the cooling fins F ₂ different substantially horseshoe shape +
Placing side diode D _2. And the cooling air is the cooling fin
F _1, F ₂ during the cooling fins F ₁ to flow smoothly, F cooling fins F ₁ so as to form a predetermined gap between the _two, rectifier A of F ₂ automotive generator overlaid with the presence .

In the rectification apparatus A [invention Problems to Solved] Fig. 9 and 10 the generator for a conventional automobile shown, first cooling fins F ₁ is joined to the rear cover C, the heat dissipation due to thermal conduction Is good. But second
Cooling fins F ₂ is provided between the first cooling fin F _1, thick plate thickness and 8 mm, and since bad Plastics insulating spacers S thermal conductivity is provided, shown in Figure 5 as the first cooling fins F ₁ is the temperature difference between the second cooling fins F _2, is nearly approximately 10 deg. For this reason, in order to improve the cooling efficiency, the area of the cooling fins is increased in a limited space, or the cooling fins are bent or embossed.

For example, an AC generator as disclosed in Japanese Patent Application Laid-Open No. 54-4303 is known, and a cylindrical insulating spacer is interposed between two cooling fins.

However, in the conventional structure, there is a problem that the plus side cooling fins located on the inside are inferior in cooling performance to the minus side cooling fins located on the outside.

On the other hand, as disclosed in U.S. Pat.
A structure in which a glass fiber insulating material is interposed between two cooling fins is known. In this structure, heat can be easily transmitted from the inner cooling fins to the outer cooling fins, and heat radiation from the inner cooling fins due to such heat transfer is expected.

However, in the configuration disclosed in U.S. Pat. No. 4,604,538, since the cooling fins, which are both heat radiating members, are arranged almost completely in close contact with each other, heat is radiated only from the surface and the edge of these heat radiating members. was there. In addition, it is necessary to adopt a configuration that is disadvantageous in terms of cost and productivity such that one cooling fin is made of a relatively thin plate made of copper and the other cooling fin is made of a relatively thick plate made of aluminum.

An object of the present invention is to improve the heat dissipation of a rectifier without lowering its electrical insulation.

Means for Solving the Problems In view of the above, the present invention relates to a vehicle AC generator having a rectifier, a fin assembly having a plurality of rectifying elements provided on cooling fins, and a fin assembly adjacent to the fin assembly. A heat dissipating member disposed between the fin assembly and the heat dissipating member;
A thin-plate insulating spacer having good heat conductivity and electrical insulation, and one of the fin assembly and the heat-dissipating member is laminated with the other with the thin-plate insulating spacer interposed therebetween; A technical means of a vehicle alternator is provided, which is provided with a layer portion having good thermal conductivity which forms a gap between the fin assembly and the heat radiating member.

[Operation and Effect of the Invention] According to the configuration of the present invention described above, since the thin plate-shaped insulating spacer is interposed between the fin assembly and the heat radiation member, the fin assembly provided with a plurality of rectifying elements and the heat radiation member Are electrically insulated from each other. On the other hand, since the thin plate-shaped insulating spacer has good thermal conductivity, the flow of heat between the fin assembly and the heat radiating member can be improved. Furthermore, although a gap is formed between the two heat dissipating members by providing the multilayer portion, the thin plate-like insulating spacer is interposed between the other heat dissipating member and the multilayer portion, and furthermore, the multilayer portion has good heat resistance. Because of the conductivity, even if a gap is formed between both heat radiating members, a good heat flow between these heat radiating members can be maintained. Further, since the multilayer portion is laminated with the other heat radiating member via the above-mentioned thin insulating spacer, it is not necessary to make the multilayer portion electrically insulative, and it is possible to exclusively use a material excellent in heat conduction. Therefore, since the thin plate-shaped insulating spacer and the weight part are interposed between both heat radiating members, even when a required gap is formed between both heat radiating members, the electric insulation between the heat radiating members is ensured, A good heat flow between the heat radiating members can be realized, and the rectifying element can be effectively radiated and cooled using both the heat radiating members.

Embodiment An automotive alternator according to the present invention will be described based on an embodiment shown in FIGS.

1 to 5 show a first embodiment of the present invention. FIG. 1 is a view showing the entire structure of an automotive alternator, and FIGS. 2 and 3 are diagrams of the automotive alternator. It is the figure which showed the rectifier.

The automotive alternator 1 according to the present embodiment includes an AC power generation unit (a rotor and a stator) in a bracket 2 made of aluminum.
And a vehicle alternator in which the rectifier 4 is disposed.
The bracket 2 includes a front bracket 20, a rear bracket 21, and a rear cover 22, which is a heat dissipating cover as a heat dissipating member, and rotatably supports a rotating shaft 25 via bearings 23, 24. At the end of the rotating shaft 25, a pulley
26 are installed. A brush holder 28 that holds a brush 27 that slides on the slip ring 31 and the rectifying device 4 are attached to the rear cover 22. A rotor core 32 is fixed to an outer periphery of a central portion of the rotating shaft 25. Fans 33 and 34 are fixed to the rotor core 32, and a rotor coil 35
Is wound. A stator core 36 is attached to the inner peripheral wall of the front bracket 20 so as to face the rotor core 32. A stator coil 37 of a three-phase AC power generation system is wound around the stator core 36.

The rectifying device 4 includes a first fin assembly as a part of a heat dissipating member in which a diode 7 is provided in a first cooling fin 5, and a second fin assembly as a fin assembly in which a diode 7 is provided in a second cooling fin 6. A fin assembly, a terminal block 91 for fixing the lead wire of the diode 7, a thin insulating spacer 8 provided between the first fin assembly and the second fin assembly, and a penetrating component. And a pipe rivet 92 as a connection member having good thermal conductivity.

The first cooling fin 5 has a substantially horseshoe shape, is fastened to the rear cover 22 by a bolt 41 as a fixing member, and forms a curved portion 52 at the end 51 on the rotating shaft 25 side. Thus the first
The first fin assembly including the cooling fins 5 is fixed to a rear cover 22 as a bracket and forms a heat dissipation member together. This first front side 53 of the cooling fins 5, - four recesses 54 for mounting the side diode D ₁ is formed. Fastening holes 57 and 58 are provided in the front side surface 53 of the first cooling fin 5. In a portion where the fastening hole 57 is provided, an overlapping portion 55 bulging in the direction of the second cooling fin 6 and partially overlapping the second cooling fin 6 is formed.

The second cooling fin 6 has a substantially horseshoe shape having an average radius different from that of the first cooling fin.
A bent portion 62 is formed. This second front side 63 of the cooling fins 6, + four recesses 64 for mounting the side diode D ₂ is formed, further, the fastening holes 67 and 68 are provided. The portion provided with the fastening hole 67 is swelled in the direction of the first cooling fin 5 to form an overlapping portion 65 that is overlapped with the overlapping portion 55 of the first cooling fin 5.

The overlapping portion 55 is a projection provided to project from the first cooling fin 5 toward the second cooling fin 6. The layer portion 65 is a projection provided to project from the second cooling fin 6 toward the first cooling fin 5. The multilayer portions 55 and 65 function as good heat conductive spacing members for maintaining the spacing between most of the first cooling fins 5 and most of the second cooling fins 6 at a predetermined interval. . Further, the multilayer portions 55 and 65, together with the thin insulating spacers 8, also function as a heat transfer means for transmitting heat from the second cooling fins 6 to the first cooling fins 5.

The first cooling fins 5 and the second cooling fins 6 have front side surfaces 53 and 63 and rear side surfaces 59 and 69 coated with resin.

The first cooling fin 5 is overlapped with the second cooling fin 6
Although the layers are layered at 65, the portions other than the layer portion 65 are arranged apart from the second cooling fins 6 with a predetermined gap therebetween, so that the cooling air for cooling the diode 7 is cooled by the first cooling fins. It flows smoothly between the fins 5 and the second cooling fins 6.

The diodes include four negative (negative and negative) diodes D ₁ as first rectifying elements mounted by soldering in the recesses 54 on the rear side surface 59 of the first cooling fin 5, and a second cooling fin. Four + sides (positive sides, as a second rectifying element) mounted as solders in the recesses 64 on the rear side surfaces 69 of the fins 6
Positive side) consisting of diode TD _2.

As shown in FIG. 4, the thin plate-shaped insulating spacer 8 is a thin plate having a thickness of 0.5 mm to 1.0 mm, is easily formed, and has heat resistance, good thermal conductivity, electrical insulation, and workability in assembly. It is a disc made of excellent ceramics (BeO, new ceramics). The diameter φD of the thin insulating spacer 8 is formed larger (16 mm to 19 mm) than the diameter φd of the multilayer portions 55 and 65. Further, the thin plate-shaped insulating spacer 8 is sandwiched between the multilayer portion 55 of the first cooling fin 5 and the multilayer portion 65 of the second cooling fin 6, and the first cooling fin 5 and the second cooling fin 6 Electrical insulation between

In the central portion 81 of the thin insulating spacer 8, the fastening hole 57 of the multilayer portion 55 of the first cooling fin 5 and the second cooling fin 6
A fastening hole 82 overlapping with the fastening hole 67 of the multilayer portion 65 is formed. The portion of the thin insulating spacer 8 that protrudes more to the side than the layer portions 55 and 65 also serves as the cooling fin 83.

Here, between the portion of the first cooling fin 5 where the fastening hole 58 is provided and the portion of the second cooling fin 6 where the fastening hole 68 is provided, plastics or ceramics having a thickness of 8.0 mm is used. An insulating tubular body (not shown) made of a metal is sandwiched.

In this embodiment, a first cooling fin 5, a second cooling fin 6, a thin insulating spacer 8 or an insulating cylinder is layered, and a lead wire of a diode 7 and a stator coil are provided on the front side of the second cooling fin 6. After assembling the terminal block 91 for holding and fixing the 37 lead wires and the like, these are caulked and fixed by pipe rivets 92 as connecting members. Thereafter, the rectifying device 4 is fixed between the rear bracket 21 and the rear cover 22 with bolts 41.

The operation of the rectifier 4 of the alternator 1 according to the present embodiment will be described with reference to the drawings.

In the alternator 1 of the present embodiment, when the rotation of the engine (not shown) is transmitted to the rotating shaft 25, the rotor core 32 is magnetized to form an N pole and an S pole. When the magnetized rotor core 32 rotates, a current flows through the stator coil 37. Since the N pole and the S pole alternately rotate, an AC voltage is generated in the stator coil 37. The diode 7 of the rectifier 4 allows the current flowing in the forward direction to pass, but blocks the current in the reverse direction, so that the rectifier 4 generates a DC voltage.

Further, the cooling air of the rectifying device 4 is introduced from the rear cover 22 and flows smoothly between the first cooling fins 5 and the second cooling fins 6 and thereafter flows into the rear bracket 21. Fins 5 are maintained at a low temperature.

The first cooling fins 5 and the second cooling fins 6 sandwich the thin thermally insulating thin insulating spacer 8 between the overlapping portions 55 and 65 bulging in a direction approaching each other, thereby providing the second cooling fins. The heat of the fins 6 can be transmitted to the first cooling fins 5 having good heat dissipation. The first cooling fins 5 and the second cooling fins 6 are disposed apart from each other with a predetermined gap in the portions other than the multilayer portions 55 and 65, although they are stacked between the multilayer portions 55 and 65. Therefore, a decrease in the creepage distance between the first cooling fin 5 and the second cooling fin 6 due to the thinning of the insulating spacer 8 can be prevented, and the cooling air for cooling the diode 7 can be cooled by the first cooling fin 5. A sufficient creepage distance can be ensured so that it can flow smoothly between the second cooling fins 6.

Further, the insulating spacer 8 is formed to have a diameter (diameter φD) larger than the diameter φd of the multilayer portions 55 and 65 and also serves as the cooling fin 83, so that the heat radiation of the insulating spacer 8 itself is improved, and the cooling effect is further improved. I do.

Therefore, as shown in FIG. 5, the temperature of the first cooling fins 5 rises slightly because heat is transmitted from the second cooling fins 6, but the temperature of the rectifier 4 as a whole decreases.
As described above, since the cooling capacity of the first and second cooling fins 5 and 6 can be improved, the four negative-side diodes D disposed on the first and second cooling fins 5 and 6 can be improved. _{by 1,} four + side diode D ₂ is cooled, thereby preventing the reduction of the service life of the diodes 7.

In addition, the electrically insulating thin insulating spacer 8 is provided in the multilayer portion 5.
By forming the protrusions 5 and 65 to protrude, electric protrusions between the first and second cooling fins 5 and 6 can be secured by the protruding portions (cooling fins 83) of the thin insulating spacer 8. For example, even if salt water is covered or a metal piece adheres, the distance between the first and second cooling fins 5 and 6 can be increased by the amount of the thin insulating spacer 8 protruding. The possibility that the first and second cooling fins 5 and 6 are short-circuited can be reduced.

By forming the first and second cooling fins 5 and 6 from materials having substantially the same thickness, the first and second cooling fins 5 and 6 can be manufactured from a common plate material. In addition, cost can be reduced.

In addition, the first cooling fin 5 has four negative diodes.
The first fin assembly provided with D ₁ and the second cooling fin 6
One of the positive side diodes D ₂ by a second pipe rivet 92 provided through the fins assembly provided with a first fin assembly and a second fin assembly and a coupling fixed to rectifier 4
The rectifying device 4 having such a strong connection is fixed to the rear cover 22 by bolts 41 so as to be able to conduct heat. Therefore, the strength of the rectifying device 4 as a single component can be sufficiently ensured, and the first and second cooling fins 5 and 6 can be surely approached via the thin insulating spacer 8.

Further, the first and second cooling fins 5 and 6 are interposed between the first and second cooling fins 5 and 6 by the thin insulating spacer 8 and the multilayer portions 55 and 65 as spacing members. A required gap can be secured therebetween. In addition, by using the thin insulating spacer 8 having good heat conductivity and electric insulation, the multilayer portions 55 and 65 do not need to have electric insulation, and can be made of a material having excellent heat conductivity. Therefore, the first and second cooling fins 5 and 6 are interposed between the first and second cooling fins 5 and 6 by interposing the thin insulating spacer 8 and the multilayer portions 55 and 65 as spacing members. Since good heat flow from the second cooling fins 6 to the first cooling fins 5 can be realized while securing the electrical insulation between them, the diode 7 can be cooled effectively.

FIG. 6 shows a second embodiment of the present invention and is a view showing a rectifying device of an alternator for an automobile.

(In this embodiment, the same functional components as those in the first embodiment are denoted by the same reference numerals.) In the present embodiment, the first cooling fin 50 and the second cooling fin 60 are arranged between the overlapping portions 55 and 65 bulging in a direction approaching each other. A disk-shaped thin insulating spacer 8 is sandwiched. Furthermore, the first cooling fins 50 and the second cooling fins 60 are provided with multilayer portions 56, 66 bulging in a direction approaching each other, and the oval thin plate-shaped insulating spacers 8a, 8b are provided between the multilayer portions 56, 66. Pinching,
More heat conductive and cooling fins 50, 60 than in the first embodiment
The cooling capacity has been improved. The portions of the oval thin plate-shaped insulating spacers 8a and 8b which are larger than the diameter of the multilayer portions 56 and 66 also serve as the cooling fins 83.

7 and 8 show a third embodiment of the present invention. FIG. 7 is a view showing a rectifier of an alternator for an automobile, and FIG. 8 is a view showing a thin plate-shaped insulating spacer of the rectifier. FIG.

In the present embodiment, a predetermined shape sandwiched between the full-layer portions 55, 56, 65, and 66 of the first cooling fin 50 and the second cooling fin 60 is provided. Is used. Fastening holes 84a, 84b, 84c are formed in the thin insulating spacer 84, and the overlapping portions 55, 56, 65, 66 of the first cooling fin 50 and the second cooling fin 60 do not overlap with each other. The portion having a shape larger than the diameter of 56, 65, 66 also serves as the cooling fin 83. The rotation shaft 25 of the thin insulating spacer 84
Is formed so that the rotating shaft 25 of the second cooling fin 60 extends along the edge 61, and the outer end 86 of the thin insulating spacer 84 is
Outer end 51a of first cooling fin 50 and second cooling fin 6
It is formed so as to be located at the outer end 61a of the zero.

In the present embodiment, the multilayered portion of the first cooling fin and the multilayered portion of the second cooling fin are bulged in a direction overlapping each other, but the multilayered portion of the first cooling fin or the second cooling fin is swelled. May be swelled in a direction overlapping with the other.

In this embodiment, a ceramic insulating spacer is used. However, insulating paper (paper insulation) in which polyamide paper is adhered to both sides of a polyester film or nomex insulating paper may be applied to the insulating spacer. The material is not limited to this embodiment as long as the material has excellent conductivity.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing the entire structure of an automotive alternator employed as a first embodiment of the present invention, and FIG. 2 shows a rectifier of the automotive alternator employed as a first embodiment of the present invention. FIG. 3 is a front view showing a rectifier of a motor alternator employed as a first embodiment of the present invention, and FIG. 4 is a perspective view showing a thin insulating spacer according to the first embodiment of the present invention. FIG. 5 is a graph showing the temperature difference between the cooling fins of the present invention and the conventional cooling fin. Sixth
FIG. 7 is a front view showing a rectifier of a vehicle alternator employed as a second embodiment of the present invention, FIG. 7 is a front view showing a rectifier of an automobile alternator employed as a third embodiment of the present invention, FIG. 8 is a perspective view showing a thin insulating spacer according to a third embodiment of the present invention. FIG. 9 is a cross-sectional view showing a conventional rectifier of a vehicle alternator, and FIG. 10 is another cross-sectional view showing a conventional rectifier of a vehicle alternator. In the figure, 1 ... alternator for automobile, 4 ... rectifier, 5, 50
...... First cooling fin, 6, 60 ... Second cooling fin,
7 Diode, 8, 8a, 8b, 84 Thin insulating spacer (heat transfer means), 41 Bolt (fixing member), 55, 65
... Multilayer part (spacing member, heat transfer means), 83 cooling fin, 91 terminal block, 92 pipe rivet (connecting member), D ₁ -side diode (first rectifying element), D ₂ ……
+ Side diode (second rectifier)

Claims (4)

(57) [Claims] 1. An automotive alternator having a rectifying device, a fin assembly comprising a plurality of rectifying elements provided on a cooling fin, a heat dissipating member disposed adjacent to the fin assembly, and the fin. Interposed between the assembly and the heat dissipating member, the thin plate insulating spacer having good heat conductivity and electrical insulation, further comprising one of the fin assembly and the heat dissipating member,
On the other side, a laminated portion having good thermal conductivity as a gap holding member for forming a gap between the fin assembly and the heat radiating member is provided. An alternator for a vehicle, characterized in that: 2. The alternator according to claim 1, wherein said heat dissipating member includes another fin assembly having a plurality of rectifying elements provided on cooling fins (5). 3. The vehicle alternator according to claim 1, wherein said heat radiating member includes a bracket (22) of the vehicle alternator. 4. The vehicle according to claim 1, wherein said multilayer portion is a projection provided on one of said fin assembly and said heat radiating member. Alternator.