JP2014171367A - Rectifier of ac generator for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rectifier of an AC generator for vehicle in which damage or peeling of a semiconductor chip, incident to scoring generated when press-fitting a rectifier element, can be prevented.SOLUTION: A rectifier 5 of an AC generator 1 for vehicle includes a negative electrode side radiation fin 53 having a fixing hole 60 with a first chamfer 60A formed at the opening end, and formed using the frame 6 of the AC generator 1 for vehicle, and a negative electrode side rectifier element 55 press-fitted in the fixing hole 60 from the opening end with a first chamfer 60A formed therein, and having a second chamfer 55A formed on the opening end side.

Description

  The present invention relates to a rectifier for a vehicle AC generator mounted on a passenger car, a truck, or the like.

  Conventionally, the shape of the outer peripheral surface of the disk portion of the rectifying element is a tapered shape in which the outer diameter on the driving start side is smaller than the outer diameter on the counter driving side, or the outer peripheral surface of the disk portion is made into a tapered shape instead of a tapered shape. There is known a rectifying device in which the inner peripheral surface of the mounting hole is tapered (see, for example, Patent Document 1). Accordingly, it is possible to prevent or reduce the occurrence and progress of scratches on the press-fitting start side of the inner peripheral surface of the mounting hole of the radiating fin due to galling or the like when starting to drive the disk portion. In addition, it is possible to prevent the contact area between the disk portion and the radiating fin from being reduced and the heat dissipation performance from being lowered and the thermal fatigue life of the rectifying element from being lowered.

JP 2009-77617 A

  By the way, although the rectifier disclosed in Patent Document 1 is provided separately from the frame, when the frame is used as a heat radiating fin for cost reduction, the mounting holes of the rectifying element must also be handled without cutting. . For example, considering the case where the attachment hole is formed together with the frame by aluminum die casting, it is not desirable to perform additional cutting on the attachment hole from the viewpoint of reducing the manufacturing cost.

  However, since the non-cut mounting hole has a larger variation in the inner diameter than cutting, the variation in tightening margin between the inner peripheral surface of the mounting hole and the outer peripheral surface of the disk portion of the rectifying element is also accompanied by this. growing. In particular, if the inner diameter of the mounting hole varies in a small direction, the press-fitting load of the rectifying element becomes excessive, and galling or the like occurs during press-fitting. For this reason, local stress is applied to the rectifying element, and there is a possibility that a failure such as breakage or peeling of the semiconductor chip may occur.

  The present invention has been created in view of the above points, and an object of the present invention is to provide a vehicle AC power generation that can prevent breakage or peeling of a semiconductor chip due to galling or the like that occurs during press-fitting of a rectifying element. It is to provide a rectifier for a machine.

  In order to solve the above-described problem, a rectifier for a rotating electrical machine for a vehicle according to the present invention includes a heat radiation fin and a rectifier element. The radiating fin has an attachment hole in which a first chamfer is formed at an opening end, and is formed using a frame of a vehicle AC generator. The rectifying element is press-fitted into the mounting hole from the opening end where the first chamfer is formed, and the second chamfer is formed on the opening end.

  By bringing the chamfered portion of the rectifying element into contact with the chamfered portion of the mounting hole provided in the frame at the start of press-fitting, it is possible to cause damage due to galling or the like near the opening end of the mounting hole at the start of press-fitting. Can be prevented or reduced. As a result, it is possible to prevent breakage or peeling of the semiconductor chip of the semiconductor element.

It is sectional drawing which shows the structure of the alternating current generator for vehicles of one Embodiment. It is sectional drawing of a negative electrode side rectifier. It is a figure which shows the correspondence of the attachment hole formed in the flame | frame, and a negative electrode side rectifier. It is a figure which shows the relationship between a chamfering angle and the press injection load of a rectifier.

  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. The vehicle alternator 1 shown in FIG. 1 includes a stator 2, a rotor 3, a brush device 4, a rectifier 5, a frame 6, a rear cover 7, a pulley 8, and the like.

  The stator 2 includes a stator core 21 and three-phase stator windings 23 wound around a plurality of slots formed in the stator core 21 at predetermined intervals. 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 a plurality of magnetic pole claws. have. A cooling fan 34 is attached to the end face of the pole core 32 on the front side by welding or the like. Similarly, a cooling fan 35 is attached to the end face of the pole core 32 on the rear side by welding or the like.

  The brush device 4 is for passing an exciting current from the rectifying device 5 to the field winding 31 of the rotor 3, and presses each of the slip rings 36 and 37 formed on the rotating shaft 33 of the rotor 3. Brushes 41 and 42 are provided.

  The rectifier 5 is for rectifying a three-phase AC voltage, which is an output voltage of the three-phase stator winding 23, to obtain a DC output power, a terminal block 51 including wiring electrodes therein, Rectifying elements 54 and 55 as a plurality of semiconductor devices mounted by press-fitting into positive-side radiating fins 52 and negative-side radiating fins 53 arranged at predetermined intervals and mounting holes provided in the respective radiating fins. It is comprised including. The press-fitting structure of the negative electrode side rectifying element 55 will be described later.

  The frame 6 accommodates the stator 2 and the rotor 3, is supported in a state where the rotor 3 can rotate around the rotation shaft 33, and a predetermined amount 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. The frame 6 is provided with a cooling air discharge window 61 at a portion facing the stator winding 23 protruding from the axial end surface of the stator core 21 and a cooling air suction window 62 at the axial end surface. Yes. The rear cover 7 covers the entire brush device 4, the rectifying device 5, and the IC regulator 12 that are attached to the outside of the rear frame 6, and protects them.

  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 8 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. DC output power is taken out from the output terminal of the rectifier 5.

  Next, the negative-side radiating fin 53 of the rectifier 5 and the negative-side rectifying element 55 attached thereto will be described. As shown in FIG. 2, the negative electrode side rectifying element 55 includes a disk portion 500, a semiconductor chip 510, and leads 520. The disk unit 500 has a cylindrical shape in which a recess 504 is formed on one end surface. The inner bottom surface of the recess 504 becomes a bonding surface 506 for soldering the semiconductor chip 510. The bottom surface side of the recess 504 (the lower surface side of the disk unit 500 in the example shown in FIG. 2) is a press-fitting surface at the time of driving, and the entire press-fitting surface is uniformly pressed.

  In the negative electrode side rectifying element 55, the semiconductor chip 510 is soldered on the joint surface 506 of the disk unit 500 by solder 512, and the lead 520 is soldered on the upper part of the semiconductor chip 510 by solder 514. Further, a protective layer 522 made of a thermosetting resin is formed so as to cover the entire semiconductor chip 510, and the entire semiconductor chip 510 is sealed with the protective layer 522.

  By the way, the disk unit 500 has a cylindrical outer peripheral surface 502. The disk portion 500 is formed of copper, aluminum, or the like, and the outer peripheral surface 502 has a knurled shape. Specifically, a plurality of convex portions are formed on the outer peripheral surface 502 in a direction parallel to the driving direction of the negative electrode side rectifying element 55. Has been.

  On the other hand, the negative-side radiating fin 53 is not configured using a single component but is configured using a part of the frame 6. The frame 6 is formed by die-casting using an aluminum material, and the axial end surface 6 </ b> A that is a part of the frame 6 is used as the negative-side radiation fin 53. An attachment hole 60 for press-fitting the negative electrode side rectifying element 55 is formed in the negative electrode side heat radiation fin 53 (axial end surface 6A). In the mounting hole 60, the inner peripheral surface 60B is a cast surface, and no additional processing is performed on the inner peripheral surface 60B formed by die casting.

  Further, the mounting hole 60 is formed with a chamfer (first chamfer) 60A at the opening end. The negative-side rectifying element 55 is press-fitted from the opening end where the chamfer 60A is formed. In FIG. 3, a direction in which the negative-side rectifying element 55 is press-fitted into the attachment hole 60 is indicated by an arrow A.

  Further, the negative-side rectifying element 55 is formed with a chamfer (second chamfer) 55A on the press-fitting front end side (opening end portion side of the mounting hole 60). The chamfer 55 </ b> A is formed on the outer peripheral surface 502 of the disk unit 500 and at the end opposite to the bottom surface.

In the present embodiment, the relationship between various dimensions and the like of the attachment hole 60 provided in the axial end surface 6A of the frame 6 and the negative electrode side rectifying element 55 press-fitted into the attachment hole 60 is set as follows.
(1) The angle a of the chamfer 60A provided in the mounting hole 60 is larger than 0 ° and smaller than the angle b of the chamfer 55A provided in the negative electrode side rectifying element 55.
(2) The starting diameter c of the chamfer 60 </ b> A of the mounting hole 60 is larger than the starting diameter d of the chamfer 55 </ b> A of the negative electrode side rectifying element 55.
(3) The surface hardness e of the inner peripheral surface 60B of the mounting hole 60 is harder than the surface hardness f of the outer peripheral surface 502 of the disk portion 500 of the negative electrode side rectifying element 55.
(4) The ratio (g: h) between the inner diameter g of the mounting hole 60 and the outer diameter h of the negative electrode side rectifying element 55 is 1: 1.01 to 1.02.

  In FIG. 4, the horizontal axis indicates the angle a of the chamfer 60A of the mounting hole 60, and the vertical axis indicates the press-fitting load. The relationship shown in FIG. 4 is that three types of values w, y, and z (w <y <z) are set as the angle b of the chamfer 55A of the negative side rectifying element 55, and the attachment hole 60 is set for these three types of angles b. The press-fit load of the negative electrode side rectifying element 55 when the angle a of the chamfer 60A is changed is examined.

  As can be seen from FIG. 4, when the angle b of the chamfer 55A of the negative side rectifying element 55 is w, the angle a of the chamfer 60A of the mounting hole 60 is made smaller than w, which is more reliable than the case where it is increased. Press-fit load can be reduced. Similarly, when the angle b of the chamfer 55A of the negative side rectifying element 55 is y, the press-fitting load can be reliably reduced by making the angle a of the chamfer 60A of the mounting hole 60 smaller than y. Can do. When the angle b of the chamfer 55A of the negative side rectifying element 55 is z, by reducing the angle a of the chamfer 60A of the mounting hole 60 to be smaller than z, the press-fit load can be surely reduced as compared with the case where it is increased. The above relationship (1) is based on these results. Note that “greater than 0 °” is a lower limit value resulting from the shape of the chamfer 60A.

  As described above, in the vehicle alternator 1 of the present embodiment, the chamfer 60A is press-fitted into the mounting hole 60 of the negative-side radiation fin 53 formed by the axial end surface 6A of the frame 6. A chamfer 55 </ b> A is formed on each side rectifying element 55. At the start of press fitting of the negative electrode side rectifying element 55, the chamfered portion of the negative electrode side rectifying element 55 is brought into contact with the chamfered portion of the mounting hole 60 provided in the frame 6, so that in the vicinity of the opening end portion of the mounting hole 60 at the start of press fitting. It is possible to prevent or reduce the progression of scratches caused by galling or the like. Thereby, damage, exfoliation, etc. of the semiconductor chip 510 can be prevented.

  Further, the angle a of the chamfer 60A of the mounting hole 60 is set to be larger than 0 ° and smaller than the angle b of the chamfer 55A of the negative electrode side rectifying element 55. Alternatively, the starting diameter c of the chamfer 60 </ b> A of the mounting hole 60 is set larger than the starting diameter d of the chamfer 55 </ b> A of the negative electrode side rectifying element 55. With such a dimensional relationship, the chamfered portion of the attachment hole 60 can be gradually pressed and expanded at the chamfered portion of the negative-side rectifying element 55, and the occurrence of galling or the like can be prevented.

  In addition, the cost can be reduced by forming the frame 6 in which the mounting holes 60 are formed by die casting using an aluminum material (aluminum or aluminum alloy, etc.) excellent in mass productivity.

  Further, by forming the outer peripheral surface 502 of the negative-side rectifying element 55 into a knurled shape, an excessive pressing load generated at the opening end of the mounting hole 60 at the start of press-fitting can be reduced, and the occurrence of galling or the like can be prevented. can do.

  In addition, the semiconductor chip 510 of the negative electrode side rectifying element 55 is sealed with a protective layer 522 using a thermosetting resin, and the semiconductor chip 510 is securely sealed to ensure that the semiconductor chip 510 is not damaged or peeled off. Can be prevented.

  In addition, this invention is not limited to the said embodiment, A various deformation | transformation implementation is possible within the range of the summary of this invention. For example, in the above-described embodiment, the case where the inner peripheral surface 60B of the mounting hole 60 provided in the frame 6 is a cast surface has been described. However, in order to increase the dimensional accuracy, the inner peripheral surface 60B is cut. The present invention can also be applied to the case of addition. When the surface of the inner peripheral surface 60B is cut thinly, the hardness of the inner peripheral surface 60B is often maintained higher than the hardness of the outer peripheral surface 502 of the negative electrode side rectifying element 55. Even in this case, by providing chamfering in each of the mounting hole 60 and the negative electrode side rectifying element 55, it is possible to prevent a scratch from being generated due to galling or the like near the opening end of the mounting hole 60 at the start of press-fitting. Alternatively, it can be reduced.

  In the above-described embodiment, the relationship between the negative electrode side rectifying element 55 and the negative electrode side radiating fin 53 has been described, but the positive electrode side rectifying element 54 can also employ a structure similar to the present invention. For example, the positive-side radiating fins 52 are formed by die casting using an aluminum material, and chamfers similar to the chamfers 60A and 55A are formed in the mounting holes provided in the positive-side radiating fins 52 and the positive-side rectifying elements 54, respectively. You may make it do. Alternatively, when a part of the frame 6 can be separated and insulated from other parts, the part of the separated frame may be used to form the positive-side radiation fins 52.

  As described above, according to the present invention, at the start of press-fitting, the chamfered portion of the rectifying element is brought into contact with the chamfered portion of the mounting hole provided in the frame, thereby galling near the opening end of the mounting hole at the start of press-fitting. It is possible to prevent or reduce the progress of scratches caused by the above.

DESCRIPTION OF SYMBOLS 1 Vehicle AC generator 6 Frame 53 Negative electrode side radiation fin 55 Negative electrode side rectifier 55A, 60A Chamfer 60 Mounting hole 60B Inner surface 500 Disk part 502 Outer surface 504 Concave part 510 Semiconductor chip

Claims (8)

A heat dissipating fin (53) having a mounting hole (60) in which a first chamfer (60A) is formed at an opening end, and formed using a frame (6) of the vehicle alternator (1);
A rectifying element (55) press-fitted into the mounting hole from the opening end where the first chamfer is formed, and a second chamfer (55A) is formed on the opening end;
A rectifier for a vehicle alternator, comprising: In claim 1,
The rectifying element is
A semiconductor chip (510);
A disk portion (500) having a recess (504) to which the semiconductor chip is soldered to the bottom surface and having a cylindrical outer peripheral surface (502);
And the second chamfer is formed on the outer peripheral surface of the disk portion and on the end opposite to the bottom surface. In claim 1 or 2,
The rectifier of an AC generator for vehicles, wherein the first chamfer angle a is larger than 0 ° and smaller than the second chamfer angle b. In any one of Claims 1-3,
The rectifier of a vehicular AC generator, wherein the first chamfer start diameter c is larger than the second chamfer start diameter d. In any one of Claims 1-4,
The frame is formed by die-casting using an aluminum material. In any one of Claims 1-5,
The mounting hole has an inner peripheral surface (60B) formed by cutting,
The vehicular AC generator rectifier is characterized in that the hardness of the inner peripheral surface is harder than the hardness of the outer peripheral surface of the rectifying element. In any of claims 1-6,
The rectifying device for an AC generator for vehicles, wherein the outer peripheral surface of the rectifying element has a knurled shape. In claim 2,
The rectifier of a vehicle AC generator, wherein the semiconductor chip is sealed with a thermosetting resin.

Images