ROTARY ELECTRIC MACHINE |
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申请号 | US14371039 | 申请日 | 2012-03-09 | 公开(公告)号 | US20140339931A1 | 公开(公告)日 | 2014-11-20 |
申请人 | Kazunori Tanaka; Toshiyuki Oonishi; | 发明人 | Kazunori Tanaka; Toshiyuki Oonishi; | ||||
摘要 | In order to prevent poor operability caused by entanglement of the fins in the heat sink during assembly without a drop in the cooling efficiency of the cooling flow along a rotation shaft, a plurality of fins 23c of the heat sink in a vehicle AC generator 1 is constituted by fin groups 123 in which fins are aligned in parallel in one direction, and an entanglement preventing portion 23d is disposed only on the respective outer side surfaces of a pair of outermost fins. | ||||||
权利要求 | |||||||
说明书全文 | The present invention relates to a rotary electric machine. As an example of a rectifying device of a conventional vehicle AC generator, a horseshoe-shaped heat sink for cooling a rectifying element is disclosed in Patent Document 1. In the heat sink, a plurality of fins, each of which extend radially, is disposed. In the heat sink, damage to the fins caused by fins entangling with each other is prevented by forming a part of the fins to be thick in the outer peripheral end side. Patent Document 2 discloses a type of press-fitting and the fixing of a rectifying element in a cooling heat sink, where a plurality of fins of the heat sink extends in a direction perpendicular to the press-fitting direction of the element, and these fins extend in parallel with each other (see FIG. 7 in Patent Document 2). Patent Document 1: Japanese Patent No. 3527516 Patent Document 2: WO 2011/070280 Of conventional heat sinks, the configuration disclosed in Patent Document 1 is reviewed first. In a configuration of a heat sink of which the pitch is relatively narrow and the length in the radial direction and the length in the axis direction are both long, in order to improve the cooling efficiency, a mold may be opened in the radiation direction in the fin molding area, since a taper, which is always generated in a molded product, cannot be ignored (first pattern). In this case, a storage efficiency in the space in the substantially cylindrical generator improves, but this configuration makes the mold complicated and takes more manufacturing space than other types, which means that productivity is not improved. The mold may be opened in the axis direction (second pattern). In this case, the mold moving space efficiency is improved but a flow passage for axial flow generated by the rotor fan becomes narrow (narrows down in the direction toward a base, which is an element support unit), that is, the cooling efficiency may deteriorate. If a thick portion is created on the outer peripheral end side of the fins to prevent entanglement, as described in The configuration in Patent Document 2, on the other hand, discloses that the heat sink base main unit is a flat plate, and a plurality of fins extends in parallel with one another, but the fins can still become entangled with each other, even if the entanglement is less frequent than the fins which are disposed radially and of which intervals expand toward the outer periphery, as disclosed in Patent Document 1. If the thickness of the end portions of the fins is partially increased in the configuration of Patent Document 2, however, the mold must be opened during manufacturing in the axis direction, and as a result, the cooling flow for radiation in the axis direction becomes narrow, or the fin pitch must be decreased to prevent this narrowing, which means that productivity cannot be improved. With the foregoing in view, it is an object of the present invention to provide a rotary electric machine, including a rectifying device that can prevent poor operability caused by entanglements of the fins in the heat sink during assembly, without dropping the cooling efficiency of the cooling flow along the rotation shaft. To achieve the object, a rotary electric machine of the present invention has: a rotor that is rotatably supported in a casing; a stator that includes a stator winding and is supported in the casing; a rectifying device that is disposed on one end side in the axis direction outside the casing and rectifies an alternate current generated in the stator winding; and a voltage regulator that is disposed on one end side in the axis direction outside the casing and regulates a level of AC voltage generated in the stator, wherein the rectifying device includes a heat sink that supports a rectifying element and has a plurality of fins to cool the rectifying element, the plurality of fins are constituted by fin groups in which fins are aligned in parallel in one direction, and in each of the fin groups, entanglement preventing portions are disposed only on the respective outer side surfaces of a pair of outermost fins among outer side surfaces of the plurality of fins. According to the present invention, poor operability caused by entanglements of the fins in the heat sink during assembly can be prevented without dropping the cooling efficiency of the cooling flow along the rotation shaft. An embodiment of a rotary electric machine according to the present invention, which is applied to a vehicle AC generator, will now be described with reference to the accompanying drawings. In the drawings, a same or a corresponding portion is denoted with a same reference symbol. As illustrated in A pulley 7 is fixed to the end of the shaft 6 which extends to the front side of the casing 4. A rotor 8 is disposed inside the casing 4, and the rotor 8 is fixed to the shaft 6. A fan 11 is fixed to both end faces of the rotor 8 in the axis direction. A stator 12 is fixed to the casing 4 so as to surround the rotor 8. On the rear side of the vehicle AC generator 1, a pair of slip rings 15, a pair of brushes 16, a brush holder 17, a voltage regulator 19, a connector 20, a rectifying device 21 and a protection cover 27 are disposed. The pair of slip rings 15 is fixed to the extended portion of the shaft 6, which extends to the rear side of the casing 4, and supplies an electric current to the rotor 8. The pair of brushes 16 is slidably disposed on the surface of the pair of slip rings 15 respectively. The brush holder 17 houses these brushes 16. The voltage regulator 19 is installed in a heat sink 18 which is disposed on the outer diameter side of the brush holder 17, and regulates the level of the AC voltage generated in the stator 12. The connector 20 is integrally molded with a mounting portion of the heat sink 18, so that the voltage regulator 19 and an external device (not illustrated) inputs/outputs signals to each other. The rectifying device 21 is disposed on the rear side of the rear bracket 3, and rectifies the AC voltage generated in the stator 12 into DC voltage. The protection cover 27 is attached to the rear brackets 3 so as to cover the brush holder 17, the voltage regulator 19 and the rectifying device 21. The rotor 8 is a Lundell type rotor, and includes a field winding 9 which generates magnetic flux when excitation current is supplied, and a pole core 10 which is disposed so as to cover the field winding 9, and forms a magnetic pole using the magnetic flux thereof. The stator 12 includes a cylindrical stator core 13, and a stator winding 14 which is wound around the stator core 13, and in which as a result of the rotation of the rotor 8 alternate current is generated by the change of magnetic flux from the field winding 9. The stator 12 is disposed so as to surround the rotor 8 in a state where the stator core 13 is held by the opening edge of the front bracket 2 and that of the rear bracket 3 in the axis direction. The rectifying device 21 includes a positive electrode side heat sink 22 where a plurality of positive electrode side rectifying elements 25 is mounted, a negative electrode side heat sink 23 where a plurality of negative electrode side rectifying elements 26 is mounted, and a circuit board 24. The rectifying device 21 will be further described in detail with reference to The rectifying device 21 is constructed in a substantial C shape when viewed in the axis direction, where the circuit board 24 is held between the positive electrode side heat sink 22 and the negative electrode side heat sink 23. The positive electrode side rectifying elements 25 and the negative electrode side rectifying elements 26 are connected so as to constitute a predetermined bridge circuit via the circuit board 24. The rectifying device 21 constructed like this is disposed on a plane orthogonal to the center of the shaft 6, at the outer peripheral side of the slip ring 15, and on this plane, the rectifying device 21 has a fan shape with the shaft 6 as the center. The rectifying device 21 is fixed in a state of being fastened to the outer end face of the rear bracket 3. As illustrated in Now a configuration of the negative electrode side heat sink 23 will be described with reference to The fins 23c are formed relatively long in the plane direction and axis direction to implement high cooling efficiency. The fins 23c are manufactured by a known aluminum die casting, which injects molten metal of aluminum alloy into a mold at high-speed and high pressure, and casts a structure having a desired shape. In this generator, as illustrated in An entanglement preventing portion 23d is disposed only on the respective outer side surfaces of a pair of outermost fins 23c, out of a fin group 123, which is a group of fins 23c extending in parallel. Each of the entanglement preventing portions 23d is a thick portion, of which thickness increases toward the outside, in an area near the tip of the corresponding outermost fin 23c respectively. As illustrated in Tapering generated in the plurality of fins 23c is along the mold opening direction, that is a direction orthogonal to the axis direction (Y direction), hence a uniform ventilation passage can be generated in the cooling flow direction (Y direction), and a drop in the cooling performance by choking in the axial flow can be prevented. Furthermore, the tip areas of the fins on the outermost side are thick, which thickness is greater than the distance between the adjacent fins, therefore an entanglement of fins of the other heat sink can be prevented. The element support hole 23b molded by the mold that opens in the axis direction (Y direction) is close to the rear face of the fins 23c (connected to the outermost side faces), therefore the outermost area of the fin group 123 having the entanglement preventing portion 23d and the element support hole 23b can be molded using a same pair of upper and lower molds (that is the upper mold 129b and the lower mold 129c), in other words, it is not necessary to provide separate molds only for molding the outermost area. The molds of the present invention are sufficient if the configuration of the heat sink can be implemented by the opening the molds in the X direction and the opening the molds in the Y direction, and the types of molds and the number of molds to be used are not especially limited. Therefore an area around the mounting hole 23a and an area around the element support hole 23b may be molded using separate molds, and/or the outermost areas of the fin group 123 and the element support hole 23b may be molded using separate molds, as necessary. A plurality of fin groups 123 may be molded together using one mold. The entanglement preventing portions 23d extend to each outermost side face in the fin group 123, and the connection terminal 24a of the circuit board 24 is disposed between the fin groups 123, as illustrated in Thus according to this embodiment, the entanglement preventing portion is formed on the respective outer surface of the outermost pair of fins out of a fin group, which is a group of a plurality of fins that extends in parallel, hence entanglement between fins can be prevented even though a plurality of fins extending in parallel is used so that the mold opening direction need not be the radiation direction or the axis direction. As a result, deterioration of operability due to entanglement of the fins in the heat sink during assembly can be prevented without a drop in the cooling efficiency of the cooling flow along the rotary shaft. Although the present invention has been described with reference to the preferred embodiment, it is apparent that numerous modifications and variations can be made by those skilled in the art based on the basic technical concept and teaching of the present invention. The negative electrode side heat sink supports three elements, and is installed at the left and right of the generator respectively as a pair, but the present invention is not limited to this, and various configurations are possible, such as only one heat sink that supports three elements, or one heat sink that supports six elements, in accordance with required specifications. 1 vehicle AC generator (rotary electric machine) 4 casing 8 rotor 12 stator 14 stator winding 21 rectifying device 22 positive electrode side heat sink 23 negative electrode side heat sink 23c fin 23d entanglement preventing portion 24 circuit board 123 fin group |