JP2009050061A - Alternator for vehicles - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reliable alternator wherein vibration in a terminal to which an external load is connected is prevented from being transmitted to a semiconductor device attached to the cooling plate of a rectifier instrument. <P>SOLUTION: A rotor 4 is placed opposite to a stator core 5 with a rotary gap in-between. A rectifier 15 converts alternating-current power induced in the winding wound on the stator core into direct-current power. The power converted into direct-current by the rectifier is taken out of a housing through an output terminal 15. A cylindrical boss 26 penetrates and holds the output terminal 15 and is formed integrally with the cooling plate 22 with the rectifier attached thereto. The cylindrical boss 26 has around its base a wall portion 42 and an air gap portion 41 that form a vibrating stress buffer portion. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a vehicular AC generator that is rotationally driven by an engine or the like and supplies electric power to an electric load, and more particularly to a vehicular AC generator characterized by a holding portion of an output terminal that extracts electric power.

  In a vehicular AC generator incorporating a rectifier for converting AC power into DC power, it is generally widely used to extract DC power to the outside through an output terminal fixed to a cooling plate.

  Further, in order to prevent cracking of the protective member for insulating and protecting the output terminal, and to prevent loosening of the fixing member for attaching the output line, the cylindrical protrusion (cylindrical boss) for attaching the output terminal is a heat sink. It is known that the output terminal formed in a hollow portion and formed in a bolt shape in the hollow portion is inserted from the inside of the generator (for example, see Patent Document 1).

JP-A-4-165949

  However, in the device described in Patent Document 1, when the load-side terminal outside the generator is vibrated by vibration from the engine side while being seated and fixed on the tubular boss, the tubular boss also vibrates. In other words, the positive-side cooling plate formed integrally with the cylindrical boss may be subjected to tensile or compressive stress in response to the vibration.

  On the other hand, since the semiconductor element for converting AC power into DC power is installed in the positive side cooling plate, the stress generated in the positive side cooling plate due to the vibration of the terminal is transmitted to the semiconductor element and transmitted to the semiconductor element. There was a concern of reducing the lifespan.

  An object of the present invention is to provide a highly reliable vehicle AC generator by preventing vibration of a terminal to which an external load is connected from being transmitted to a semiconductor element mounted on a cooling plate of a rectifier. It is in.

(1) In order to achieve the above object, the present invention provides a housing, a stator core accommodated and held in the housing, a rotor disposed opposite to the stator core with a rotation gap, and the fixed A rectifier that converts AC power induced in the winding wound around the core to DC power, and a generator-side output terminal for taking out the power converted to DC by the rectifier to the outside of the housing; An AC generator having a cylindrical boss portion formed integrally with a cooling plate having the output terminal penetrating and mounted with the rectifier, wherein the cylindrical boss has a vibration stress buffer around its base portion. A part is provided.
With this configuration, it is possible to improve the reliability by preventing the vibration of the terminal to which the external load is connected from being transmitted to the semiconductor element mounted on the cooling plate of the rectifier.

  (2) In the above (1), preferably, the vibration stress buffering portion is at least a space portion opened in the rectifier side position direction.

  (3) In the above (2), preferably, the space opened in the rectifier side position direction is formed by a cooling plate meat portion that is formed in pieces in an annular direction connecting the cylindrical boss and the cooling plate. It is what.

  (4) In said (2), Preferably, the space opened in the said rectifier side position direction is a ditch | groove formed of the thin part.

  (5) In the above (2) or (3), preferably, the space penetrates the cooling plate.

  According to the present invention, it is possible to improve the reliability by preventing the vibration of the terminal to which the external load is connected from being transmitted to the semiconductor element mounted on the cooling plate of the rectifier.

Hereinafter, the configuration of an automotive alternator according to an embodiment of the present invention will be described with reference to FIGS. In the following example, a vehicle water-cooled alternator is illustrated as an AC generator.
First, the overall configuration of the vehicle AC generator according to the present embodiment will be described with reference to FIG.
FIG. 1 is a cross-sectional view showing an overall configuration of an automotive alternator according to an embodiment of the present invention.

  A rotor 4 fitted with a field winding 3 is fixed to the rotor shaft 1, and a stator core 5 is disposed around the rotor 4 via a minute gap. A stator winding 6 is attached to the stator core 5. Both ends of the rotor shaft 1 are held by a pair of housings (front housing, rear housing) 9 and 10 via bearings 7 and 8. Further, the stator core 5 is tightly fixed to the inner peripheral surface of the rear housing 10 by press fitting, shrink fitting or the like.

  A slip ring 12 for supplying current to the field winding 3 is disposed around one end 1 a of the rotor shaft 1 protruding from the rear housing 10. The slip ring 12 is connected to the field winding 3. The slip ring 12 is in contact with the brush held by the brush holder 14. A power module (not shown) for controlling the output power is provided integrally with the brush holder 14. The power module is driven by a control command from the outside, and the field current supplied to the field winding 3 is controlled, whereby the output power of the AC generator is controlled.

  A pulley 2 is fixed to the other end of the rotor shaft 1 protruding from the rear housing 10. A driving force from a driving force source such as an engine is transmitted to the pulley 2 and the rotor 4 is rotated.

  On the outer surface of the rear housing 10, a rectifying device 15 in which a semiconductor element is installed is attached. The rectifier 15 is fixed to the housing 10 by bolts 17 and nuts 18 installed in the housing 10.

  The rectifier 15 is a device that converts AC power induced in the stator winding 6 into DC power, and constitutes a negative-side device, a positive-side device, and a rectifier circuit having a semiconductor element that converts it into DC power. The circuit terminal 24 has a conductive member.

  The negative-side cooling plate 21 in which the semiconductor element of the negative-side device of the rectifier 15 is installed constitutes a part of the housing that forms the water channel. That is, a recess 10 a is formed in the circumferential direction on the outer peripheral side of the housing 10. By closing the opening of the recess 10a with the negative-side cooling plate 21, the recess 10a becomes a cooling water passage, and the cooling water flows through this passage.

  The positive-side cooling plate 22 on which the semiconductor element of the positive-side device of the rectifier 15 is installed is insulated from the negative-side cooling plate 21 by an insulator (insulator 23 in FIG. 3). In addition to the semiconductor element, the positive-side cooling plate 22 is provided with an output terminal 25 for outputting DC power to the outside of the generator. Around the output terminal 25, a substantially cylindrical boss portion 26 having a surface on which a load terminal outside the generator is seated is installed. The boss portion 26 has an integral structure with the positive-side cooling plate 22.

  The AC power induced in the stator winding 6 is output to the rectifier 15 through the coil terminal 13. The rectifier 15, the brush holder 14, and the power module are covered with a rear cover 16.

  A fan 11 is fixed to the rotor 4, and cooling air passes through the alternator through an external air intake (not shown) provided in the housing and the rear cover when the rotor 4 rotates. The cooling air takes heat generated from the field winding 3 and the rectifier 15 of the alternator to increase the power generation efficiency.

Next, the configuration of the one end side of the rotating shaft of the vehicle alternator according to the present embodiment will be described with reference to FIG.
FIG. 2 is a plan view showing the configuration of one end side of the rotating shaft of the vehicle alternator according to the embodiment of the present invention. The same reference numerals as those in FIG. 1 denote the same parts.

  The negative electrode side device of the rectifying device 15 includes a negative electrode side cooling plate 21 and six semiconductor elements 31b1, 31b2, 31b3, 31b4, 31b5, 31b6. The semiconductor elements 31b1,..., 31b6 are rectifying diodes. The semiconductor elements 31b1,..., 31b6 are fixed to the negative-side cooling plate 21 by press-fitting. As illustrated in FIG. 1, the negative-side cooling plate 21 constitutes a water channel and serves as one end of the rectifier circuit. The heat of the semiconductor elements 31b1,..., 31b6 is transferred to the negative-side cooling plate 21, thereby cooling the entire rectifier.

  The positive side device of the rectifying device 15 includes a positive side cooling plate 22 and six semiconductor elements 31a1, 31a2, 31a3, 31a4, 31a5 and 31a6. The semiconductor elements 31a1,..., 31a6 are fixed to the positive-side cooling plate 22 by press-fitting, and the heat of the semiconductor elements 31a1, ..., 31a6 is transferred from the positive-side cooling plate 22 to the negative-side cooling plate 21. The entire rectifier is cooled.

  One end of the semiconductor elements 31b1,..., 31b6, 31a1,..., 31a6 of the negative electrode side device and the positive electrode side device are joined to one end of the conductive member of the circuit terminal 24 by welding or the like to constitute a rectifier circuit.

Next, the configuration in the vicinity of the rectifier and the output terminal of the vehicle alternator according to the present embodiment will be described with reference to FIGS. 3 and 4.
FIG. 3 is a perspective view showing a configuration near the rectifier and the output terminal of the automotive alternator according to the embodiment of the present invention. FIG. 4 is a cross-sectional view showing a configuration near the rectifier and the output terminal of the automotive alternator according to the embodiment of the present invention. 3 and 4, the same reference numerals as those in FIGS. 1 and 2 denote the same parts.

  As shown in FIG. 3, the circuit terminal 24 has a seating surface 24 a of the nut 18 for fixing the rectifying device 15 to the housing 10, and plays a role of transmitting a fastening force between the nut 18 and the bolt 17. The positive side cooling plate 22 is fixed by a circuit terminal 24.

  The positive-side cooling plate 22 in which the semiconductor element of the positive-side device of the rectifier 15 is installed is insulated from the negative-side cooling plate 21 by an insulator 23.

  As shown in FIG. 4, a substantially cylindrical boss portion 26 having a surface on which the terminal 50 of the load outside the generator is seated is installed around the output terminal 25. The boss portion 26 has an integral structure with the positive-side cooling plate 22. The terminal 50 is fixed to the output terminal 25 and the boss portion 26 by a fastening member 51.

  The positive side cooling plate 22 has an output terminal 25 for outputting DC power to the outside of the generator with respect to the surface 22a (in this example, the radial direction) on which the semiconductor element 31a1 of the positive side cooling plate 22 is installed. These are press-fitted and fixed in a substantially perpendicular direction (in this example, the axial direction).

  Around the output terminal 25, a substantially cylindrical boss portion 26 is provided. The boss portion 26 has an integral structure with the positive-side cooling plate 22. That is, the boss portion 26 is integrally formed in a substantially perpendicular direction (axial direction in this example) to the surface 22a (radial direction in this example) of the positive-side cooling plate 22 where the semiconductor element 31a1 is installed. Yes.

  Here, in the positive-side cooling plate 22, a portion (enclosed by a dotted line in FIG. 4) that deforms in a substantially perpendicular direction (in this example, the axial direction) from the surface 22 a on which the semiconductor element 31 a 1 is installed in order to form the boss portion 26. This portion is referred to as a boss root portion 40.

  Although the boss portion 26 is integrally formed with the positive-side cooling plate 22, a gap 41 is provided in a part of the boss root 40, so the boss 26 is a boss root other than the gap 41. It is the structure supported by the cooling plate meat part 42 of this. These gap portion 41 and cooling plate meat portion 42 constitute a vibration stress buffer portion.

  As shown in FIG. 3, one of the gap portions 41 of the boss root portion 40 is the direction of the semiconductor element 31 a 1 closest to the boss portion 26 among the semiconductor elements 31 a 1,..., 31 a 6 installed on the positive-side cooling plate 22. Is installed.

  As shown in FIG. 4, the cooling plate meat portion 42 of the boss root portion 40 has a rib shape from the boss portion 26 to the surface 22 a on which the semiconductor element of the positive-side cooling plate 22 is installed.

  As shown in FIG. 3, one of the cooling plate meat portions 42 of the boss root portion 40 is the direction of the fastening portion of the bolt 17 and the nut 18 that fix the rectifying device 15 including the positive-side cooling plate 22 to the housing 10. Is located.

  The gap 41 may be filled with a cushioning material such as silicon rubber.

  Because of the configuration described above, when the terminal outside the generator connected to the generator vibrates, the boss portion 26 that becomes the seating surface of the terminal also vibrates, and the positive side on which the boss portion 26 is integrally formed Stress is generated in the cooling plate 22, particularly in the boss root portion 40. However, although stress is generated in the cooling plate meat portion 42 of the boss root portion 40, no stress is generated in the gap portion 41. This suppresses the generation of stress in the direction in which the gap 41 of the positive-side cooling plate 22 is located, and suppresses the generation of stress to the adjacent semiconductor element 31a1 due to the vibration of the load connection terminal outside the generator. it can.

  Further, since one of the meat portions 42 at the base of the boss is located in the direction of the fixing point of the rectifying device 15, the rigidity for supporting the boss 26 is improved, and the vibration of the load connection terminal outside the generator is increased. Since the vibration of the boss portion 26 caused by the above can be suppressed, the stress suppressing effect due to the above-described gap can be further improved.

  Moreover, by making the rib portion 42 of the boss base portion, the rigidity for supporting the boss portion 26 is improved, and the vibration of the boss portion 26 due to the vibration of the load connection terminal outside the generator can be suppressed. Therefore, it is possible to further improve the stress suppressing effect due to the above-described gap.

  Further, when the terminal 50 of the load outside the generator is hotter than the positive side cooling plate 22 or when the boss part 26 is hotter than the positive side cooling plate due to heat generation, the heat of the terminal or boss part is increased by the positive side cooling plate. There is also a concern that the temperature of the semiconductor element installed on the positive-side cooling plate is increased and the life of the semiconductor element is reduced by heat. On the other hand, since the gap 41 is provided in the direction of the semiconductor element 31a1 installed on the positive-side cooling plate 22 of the boss root 40, the terminal 50 or the boss is compared with the case where there is no gap. Since the heat transfer distance from 26 is long and the thermal resistance is large, heat transfer to the semiconductor element 31 can be suppressed.

  As described above, according to the present embodiment, the vibration stress buffering portion is formed around the base portion of the cylindrical boss portion that penetrates and holds the output terminal, thereby rectifying the vibration of the terminal to which the external load is connected. It is possible to provide a highly reliable generator by preventing transmission to the semiconductor element mounted on the cooling plate of the apparatus.

Next, the configuration of an automotive alternator according to another embodiment of the present invention will be described with reference to FIG. In the following example, a vehicle water-cooled alternator is illustrated as an AC generator. The overall configuration of the vehicle alternator according to this embodiment is the same as that shown in FIG. Moreover, the structure of the one end side of the rotating shaft of the vehicle alternator according to this embodiment is the same as that shown in FIG.
FIG. 5 is a cross-sectional view showing a configuration near the rectifier and output terminal of a vehicular AC generator according to another embodiment of the present invention. In addition, the same code | symbol as FIGS. 1-4 shows the same part.

  In the present embodiment, the boss base portion 40 includes a cooling plate flesh portion 42 similar to that shown in FIG. 4, a thin flesh portion 43 formed by leaving a thin portion of the member relative to the flesh portion 42, and a gap portion (concave groove) 42 a. Is forming. Similar to the first embodiment shown in FIG. 3, the gap 42 a is provided with an angle in a direction facing the semiconductor element 31 a 1 installed on the positive-side cooling plate 22. The thin portion 43, the gap portion 42a, and the cooling plate portion 42 constitute a vibration stress buffer portion.

  The gap 42a may be filled with a cushioning material such as silicon rubber.

  Since the thin-walled portion 43 is stressed due to the configuration described above, the stress generation range is limited to a local range of the thin-walled portion because the rigidity is lower than that of the thin-walled portion 42 at the opposite position. In the direction of the semiconductor element 31a installed on the positive-side cooling plate 22 where 43 is located, the generation of stress is suppressed, and the generation of stress on the semiconductor element 31a due to the vibration of the load connection terminal outside the generator is suppressed. it can.

  Further, since one of the meat portions 42 at the base of the boss is located in the direction of the fixing point of the rectifying device 15, the rigidity for supporting the boss 26 is improved, and the vibration of the load connection terminal outside the generator is increased. Since the vibration of the boss portion 26 due to can be suppressed, the stress suppressing effect by the thin-walled portion 43 can be further improved.

  In addition, since the rib portion of the boss base portion has a rib shape, rigidity to support the boss portion is improved, and vibration of the boss portion 26 due to vibration of the load connection terminal outside the generator can be suppressed. The stress suppressing effect by the thin-walled portion 43 can be further improved.

  Even when the external terminal connected to the generator is hotter than the generator or when the boss 26 is hotter than the positive cooling plate due to heat generation, it is installed on the positive cooling plate 22 of the boss root 40. Since the thin portion 43 is provided in the direction of the semiconductor element 31a, the thermal resistance is larger than that of the cooling plate thickness portion 42. Therefore, the terminal 50 or the boss portion 26 leads to the semiconductor element 31a. There is also an effect of suppressing heat transfer.

As described above, according to the present embodiment, the vibration stress buffering portion is formed around the base portion of the cylindrical boss portion that penetrates and holds the output terminal, thereby rectifying the vibration of the terminal to which the external load is connected. It is possible to provide a highly reliable generator by preventing transmission to the semiconductor element mounted on the cooling plate of the apparatus.

It is sectional drawing which shows the whole structure of the alternating current generator for vehicles by one Embodiment of this invention. It is a top view which shows the structure of the rotating shaft one end side of the alternating current generator for vehicles by one Embodiment of this invention. It is a perspective view showing composition near a rectifier and an output terminal of an alternator for vehicles by one embodiment of the present invention. It is sectional drawing which shows the structure of the rectifier and output terminal vicinity of the alternating current generator for vehicles by one Embodiment of this invention. It is sectional drawing which shows the structure of the rectifier and output terminal vicinity of the alternating current generator for vehicles by other embodiment of invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Rotor shaft 2 ... Pulley 3 ... Field winding 4 ... Rotor 5 ... Stator core 6 ... Stator winding 7, 8 ... Bearing 9 ... Front housing 10 ... Rear housing 11 ... Fan 12 ... Slip ring 13 ... Coil terminal 14 ... Power module 15 ... Rectifier 16 ... Rear cover 17 ... Bolt 18 ... Nut 21 ... Negative side cooling plate 22 ... Positive side cooling plate 22a ... Semiconductor element installation surface 23 of positive side cooling plate ... Insulator 24 ... Circuit Terminal 25 ... Output terminal 26 ... Boss part 31 ... Semiconductor element 40 ... Boss root part 41 ... Cooling plate gap 42 at the boss root part ... Cooling plate meat part 42a at the boss root part ... Gap part 43 formed with a thin thickness. ... Cooling plate thin part 50 at base of boss ... Terminal 51 of load outside generator ... Fastening member

Claims (5)

AC which is induced by a housing, a stator core housed and held in the housing, a rotor disposed opposite to the stator core with a rotation gap, and a winding wound around the stator core A rectifier that converts electric power into direct-current power, a generator-side output terminal for taking out the electric power converted into direct-current by the rectifier to the outside of the housing, a cooling that penetrates and holds the output terminal and is equipped with the rectifier An AC generator having a cylindrical boss formed integrally with a plate,
The tubular boss is provided with a vibration stress buffering portion around a base portion thereof. In the vehicle alternator according to claim 1,
The vehicular AC generator is characterized in that the vibration stress buffering portion is at least a space portion opened in the rectifier side position direction. In the vehicle alternator according to claim 2,
The space opened in the rectifier side position direction is formed by a cooling plate meat portion that connects the cylindrical boss and the cooling plate and is formed in pieces in the annular direction. In the vehicle alternator according to claim 2,
The vehicular AC generator characterized in that the space opened in the rectifier side position direction is a concave groove formed by a thin portion. In the vehicle alternator according to claim 2 or 3,
The AC generator for vehicles, wherein the space penetrates a cooling plate.

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