JP2011083071A - Alternator for vehicles - Google Patents

Abstract

A vehicular AC generator capable of improving the heat dissipation of a field coil is provided.
A shaft portion 112a, a pair of disk portions 112b extending in an outer diameter direction from both axial ends of the shaft portion 112a, and a plurality of claw magnetic pole portions 112c formed so as to extend from the disk portion 112b in the axial direction are provided. A coil bobbin 17 having a Landel-type rotor core 112F, 112R having a body portion 171 that is externally inserted into the shaft portion 112a, and a pair of flange portions 172 that extend from both ends of the body portion 171 along the disk portion 112b in the outer diameter direction. A stator having an iron core wound around the armature coil and disposed opposite to the outer periphery of the claw magnetic pole portion 112c of the rotor cores 112F and 112R, and the field coil 12 wound around the body portion 171 of the coil bobbin 17. , The thermal conductivity of the coil bobbin 17 is greater than the thermal conductivity of the field coil 12. As larger, setting the thermal conductivity of the coil bobbin 17.
[Selection] Figure 3

Description

  The present invention relates to a vehicle AC generator.

  As a structure of a vehicle AC generator rotor, for example, a structure in which a field coil is wound around a rotor core having a Landel claw magnetic pole via a coil bobbin is known. The coil bobbin includes a winding drum portion around which the field coil is wound, and flange portions formed on both sides of the winding drum portion.

  In such an AC generator for vehicles, there is a problem that the temperature of the field coil rises and the resistance of the field coil increases due to heat generation due to Joule loss when a current is passed through the field coil. . When the resistance of the field coil increases, the current flowing through the field coil decreases, so the magnetomotive force decreases and the output current decreases.

  Since heat due to Joule loss is dissipated from the field coil through the coil bobbin and the rotor core, in order to reduce the temperature rise of the field coil due to Joule loss, the material constituting the heat dissipation path, that is, the rotor core, the coil bobbin and the field magnet The thermal conductivity of the coil is important. Conventionally, the thermal conductivity is high in the order of the rotor core, field coil, and coil bobbin, and the low thermal conductivity of the coil bobbin has hindered heat dissipation. A conventional coil bobbin is made of nylon resin or the like, and has a thermal conductivity of about 0.4 W / m · K.

  Therefore, in order to promote heat dissipation from the rotor coil and improve the output current, a structure in which a through hole is formed in the winding body of the coil bobbin and a hole member made of good heat conductive rubber is held in the through hole. It has been proposed (see, for example, Patent Document 1).

Japanese Patent No. 3538484

  However, in the thing of patent document 1, since the thermal conductivity of the hole member which consists of good heat conductive rubber hold | maintained at the through-hole is only high, the low thermal conductivity of a coil bobbin main body still becomes a problem. There is a problem that sufficient heat dissipation cannot be expected.

The present invention relates to a Landel-type rotor core having a shaft portion, a pair of disk portions extending in the outer diameter direction from both axial ends of the shaft portion, and a plurality of claw magnetic pole portions formed so as to extend from the disk portion in the axial direction. And a coil bobbin having a body part extrapolated to the shaft part, a pair of flange parts extending in the outer diameter direction from both ends of the body part along the disk part, and a field coil wound around the body part of the coil bobbin, And a stator having an iron core around which an armature coil is wound, which are opposed to each other so as to surround the outer periphery of the claw magnetic pole portion of the rotor core, The thermal conductivity of the coil bobbin is set so as to be larger than the thermal conductivity of.
The coil bobbin may be formed of a resin material containing a metal filler so that the thermal conductivity of the coil bobbin is 2.0 W / m · K or more and 15.0 W / m · K or less. The coil bobbin may be formed of a metal whose surface is subjected to insulation treatment so that the conductivity is 2.0 W / m · K or more.

  ADVANTAGE OF THE INVENTION According to this invention, the heat dissipation of a field coil can improve and the performance improvement of the alternating current generator for vehicles can be aimed at.

1 is a cross-sectional view of an automotive alternator that constitutes an embodiment of the present invention. 2 is a diagram illustrating an example of a rectifier circuit 11. FIG. 4 is a cross-sectional view for explaining the structure of a rotor 112. FIG. 3 is a perspective view of a coil bobbin 17. FIG. It is a figure explaining a heat dissipation path. It is a figure which shows the relationship between the thermal conductivity of the coil bobbin 17, and the temperature rise of the field coil 12. FIG. It is a figure explaining 2nd Embodiment. It is a figure which shows the flow of the magnetic flux in the rotor in the alternating current generator for vehicles. It is a figure which shows the shape of the rotor core in 3rd Embodiment. It is a figure which shows the relationship between dimension B, C, E related to the cross-sectional area in a magnetic flux path | route, and S showing the cross-sectional area of a coil winding area | region.

Hereinafter, the best mode for carrying out the present invention will be described with reference to the drawings.
-First embodiment-
FIG. 1 is a diagram showing a first embodiment of the present invention, and is a cross-sectional view showing a configuration of a vehicle AC generator 100. A pulley 1 is attached to the tip of the shaft 18 provided with the rotor 112, and a belt is stretched between the pulley 1 and a pulley attached to a drive shaft of an engine (not shown). The shaft 18 is rotatably supported by a bearing 2F provided on the front bracket 14 and a bearing 2R provided on the rear bracket 15. The stator 4 arranged to face the rotor 112 with a slight gap is held so as to be sandwiched between the front bracket 14 and the rear bracket 15.

  The rotor 112 constitutes a Landel type rotor (claw magnetic pole type rotor) as shown in FIG. The rotor 112 has a front side rotor core 112F in which a rotor claw magnetic pole 112c extending from the front bracket 14 side to the rear bracket 15 side is formed, and a rear side rotor core 112R in which a rotor claw magnetic pole 112c extending in the opposite direction is formed. is doing. The rotor claw magnetic pole 112c of the rotor core 112F and the rotor claw magnetic pole 112c of the rotor core 112R are alternately arranged in the rotor circumferential direction. The field coil 12 is disposed around the shaft 112a inside the rotor claw magnetic pole 112c.

  A slip ring 9 for supplying power to the field coil 12 is provided at the rear end of the shaft 18. Electric power for generating a field is supplied to the field coil 12 from a battery mounted on the vehicle via the brush 8 that contacts the slip ring 9. On the front and rear end surfaces of the rotor 112, a cooling front fan 7F and a rear fan 7R that rotate in synchronization with the rotor 112 are provided.

  On the other hand, the stator 4 includes a stator core 21 and a stator winding 5 and is disposed so as to face the rotor 112 with a slight gap. The stator core 21 is held by the front bracket 14 and the rear bracket 15 so as to be sandwiched from the front and rear. The stator winding 5 is composed of a three-phase winding, and the lead wire of each winding is connected to the rectifier circuit 11. The rectifier circuit 11 is constituted by a rectifier element such as a diode, and constitutes a full-wave rectifier circuit. For example, when a diode is used, the cathode terminal of the diode is connected to the terminal 6, and the terminal on the anode side is electrically connected to the vehicle alternator main body. Note that the rear cover 10 provided with air holes for cooling serves as a protective cover for the rectifier circuit 11.

  FIG. 2 shows a configuration of a rectifier circuit 11 that performs three-phase full-wave rectification using six diodes 111. The rectifier circuit 11 is formed by connecting three sets of series circuits composed of two diodes 111 in parallel. The U, V, and W phase stator windings 5 are connected by a three-phase Y connection, and the terminal on the anti-neutral point side is connected to the connection point of the diodes 111 connected in series. The cathode of the upper (plus side) diode 111 is common and is connected to the plus terminal of the battery 99. The anode of the lower (minus) diode 111 is connected to the minus terminal of the battery 99.

  Next, the power generation operation will be described. As described above, the pulley 1 and the engine-side pulley are connected by the belt, and the rotor 112 rotates as the engine rotates. When current flows through the field coil 12 provided in the rotor 112, the rotor claw magnetic pole 112c is magnetized. Therefore, when the rotor 112 rotates, a rotating magnetic field is formed, and a three-phase induced electromotive force is generated in the stator winding 5. The voltage is full-wave rectified by the rectifier circuit 11 described above to generate a DC voltage. The positive side of the DC voltage is connected to the terminal 6 and further connected to the battery 99. Although details are omitted, the field current is controlled so that the rectified DC voltage becomes a voltage suitable for charging the battery.

  The structure of the rotor 112 will be described with reference to FIG. A front-side rotor core 112F and a rear-side rotor core 112R formed of a magnetic material are serrated and connected separately at a substantially central portion in the rotation axis direction of the shaft 18 so as to rotate integrally with the shaft 18. The front-side rotor core 112F and the rear-side rotor core 112R are attached to the shaft 18 so that the shaft portions 112a face each other and come into contact with each other. The movement in the axial direction is restricted.

  As described above, the plate-like fans 7F and 7R having a plurality of blades on the outer peripheral side are attached to both end faces in the rotation axis direction of the rotor 112, and rotate integrally with the rotor 112. These fans 7F and 7R circulate air from the inner peripheral side to the outer peripheral side by centrifugal force due to rotation. It should be noted that the front fan 7F on the front bracket 14 side has smaller blades than the rear fan 7R on the rear bracket 15 side, and the flow rate of air to be circulated is smaller than that of the rear fan 7R.

  Each of the front rotor core 112F and the rear rotor core 112R includes a shaft portion 112a located on the inner peripheral side, a disk portion 112b extending from the shaft portion 112a in the outer diameter direction, and a plurality of rotors extending from the disk portion 112b in the axial direction. Claw magnetic pole 112c. As described above, the front rotor core 112F and the rear rotor core 112R are attached to the shaft 18 so that the axial ends of the respective shaft portions 112a are in contact with each other, thereby constituting a Landel type iron core.

  A field coil 12 wound around the coil bobbin 17 is disposed between the outer periphery of the shaft portion 112a and the inner periphery of the rotor claw magnetic pole 112c. The field coil 12 is wound around the rotating shaft around the body of the coil bobbin 17. Insulation of the field coil 12 is maintained by a coil bobbin 17 interposed between the rotor cores 112F and 112R and the field coil 12. Both ends of the coil conductor constituting the field coil 12 extend along the shaft 18 and are connected to the slip ring 9 described above. Therefore, the direct current supplied from the brush 8 through the slip ring 9 flows through the field coil 12, and the rotor 112 is magnetized accordingly, and a magnetic path that circulates around the field coil 12 is formed in the rotor 112. .

  The current supplied to the field coil 12 is controlled in accordance with the state of the battery 99 so that power generation is started when the power generation voltage becomes higher than the vehicle battery voltage. An IC regulator (not shown) as a voltage control circuit for adjusting the generated voltage is built in the rectifier circuit 11 disposed inside the rear cover 10 shown in FIG. 1, and the terminal voltage of the terminal 6 is always constant. It is controlled to be a voltage.

  Next, the coil bobbin 17 will be described with reference to FIG. The coil bobbin 17 includes a cylindrical body 171 around which the field coil 12 is wound, and flanges 172 provided at both ends of the cylinder of the body 171. The coil bobbin 17 is attached to the rotor cores 112F and 112R so that the shaft portions 112a of the rotor cores 112F and 112R are fitted into the inner periphery of the body portion 171. As a result, the body portion 171 of the coil bobbin 17 is in contact with the periphery of the shaft portion 112 a, and the flange portion 172 is in contact with the disk portion 112 b of the rotor core 112.

  When the coil bobbin 17 is made of a non-conductive material, the field coil 12 is directly wound around the body 171 of the coil bobbin 17. When the coil bobbin 17 is made of a conductive material, the field coil 12 is wound after the surface of the coil bobbin 17 is insulated.

  FIG. 5 is a view for explaining a heat radiation path due to Joule loss generated in the field coil 12. As shown by the arrow in FIG. 5, heat due to Joule loss generated in the field coil 12 is transmitted from the field coil 12 through the coil bobbin 17 to the disk portion 112b of the rotor cores 112F and 112R, and the front bracket 14 side front side. Heat is radiated from the fan 7F and the rear fan 7R on the rear bracket 15 side.

  Here, we focus on the thermal conductivity of the heat dissipation path. The field coil 12 is configured by winding a conductor in a plurality of alignments, but here it is idealized and considered as an integral one. In that case, the thermal conductivity of the field coil 12 is about 1.9 W / m · K. Further, the rotor cores 112F and 112R (iron cores) constituting the rotor 112 have a thermal conductivity of about 83 W / m · K. Since the materials for the field coil 12 and the rotor cores 112F and 112R should be selected based on electromagnetic characteristics, it is difficult to improve the thermal conductivity of the field coil 12 and the rotor cores 112F and 112R.

  Conventionally, the magnitude relationship of the thermal conductivity of the material constituting the heat dissipation path shown in FIG. 5 is the rotor cores 112F and 112R> the field coil 12> the coil bobbin 17, and the heat dissipation of the field coil 12 is improved. Above, the low thermal conductivity of the coil bobbin 17 has been an obstacle. Therefore, in this embodiment, the heat conductivity of the coil bobbin 17 is improved to improve the heat dissipation of the field coil 12. As described above, the thermal conductivity of the field coil 12 obtained by making it ideal as an integral body is about 1.9 W / m · K, so the thermal conductivity of the coil bobbin 17 is set to 2.0 W / m · K or more. Then, “coil bobbin 17> field coil 12” is satisfied, and the heat dissipation performance of the field coil 12 can be improved.

  FIG. 6 shows the relationship between the thermal conductivity of the coil bobbin 17 and the temperature rise of the field coil 12. The vehicle alternator is generally divided into two types according to the outer diameter, and there are a φ128 type and a φ139 type. The calculation data of FIG. 6 is shown for the φ139 type, but the φ128 type has the same relationship. As shown in FIG. 6, when the thermal conductivity is up to about 0.5 W / m · K, the temperature rise rapidly decreases as the thermal conductivity increases, and the thermal conductivity becomes the thermal conductivity of the field coil 12. At 2.0 W / m · K or more, which is larger than 1.9 W / m · K, the temperature rise is almost the same.

  The thermal conductivity of the conventional coil bobbin is in the range indicated by the symbol F, and the temperature rise of the field coil is about 65 to 95 ° C. On the other hand, when the thermal conductivity of the coil bobbin 17 is 2.0 W / m · K or more, the temperature rise is lower than 60 ° C., and under this condition, the temperature rise of the field coil 12 can be sufficiently suppressed. It is shown.

  In order to configure the coil bobbin 17 to have a thermal conductivity of 2.0 W / m · K or more, in this embodiment, the glass bobbin 17 is configured by impregnating a glass fiber sheet with a high thermal conductivity resin and curing it. . The high thermal conductive resin is configured by mixing metallic particles in an epoxy resin, and is, for example, an epoxy resin containing a metal filler. With this configuration, the thermal conductivity of the coil bobbin 17 can be about 5.0 W / m · K. Further, increasing the amount of the metal filler added to the epoxy resin can be expected to further improve the thermal conductivity, but the molding processability is inferior. Therefore, the configuration of the coil bobbin 17 becomes difficult unless a resin having a thermal conductivity of 15.0 W / m · K or less is used.

  That is, when the coil bobbin 17 is manufactured using a high thermal conductive resin obtained by mixing metallic particles with an epoxy resin, the thermal conductivity is 2.0 W / m · K or more and 15.0 W / m · K or less. Thus, it is necessary to set the amount of the metallic filler. By doing so, the temperature rise of the field coil 12 can be greatly reduced as compared with the prior art while maintaining good moldability of the coil bobbin 17.

  With this configuration, the magnitude relationship of the thermal conductivity of the material constituting the heat dissipation path shown in FIG. 5 is the rotor cores 112F, 112R> coil bobbin 17> field coil 12, which has conventionally hindered heat dissipation. Further, the low thermal conductivity of the coil bobbin 17 is eliminated. Therefore, the Joule loss generated in the field coil 12 is effectively transmitted to the front fan 7F and the rear fan 7R via the coil bobbin 17 and the rotor cores 112F and 112R, and is radiated from the fans 7F and 7R. As a result, an increase in resistance of the field coil 12 due to a temperature rise can be suppressed to a low level, so that the current flowing through the field coil 12 is increased and the magnetomotive force of the rotor is increased, thereby improving the generator output. it can. For example, when the thermal conductivity of the coil bobbin 17 is 5.0 W / m · K, the output can be improved by about 10 A in terms of current value compared to the case where a coil bobbin made of a conventional material is used.

  Moreover, there is a thermal resistance as an index representing the ease of passing heat. In the conventional rotor configuration, the thermal resistance of the coil bobbin 17 is 0.35 K / W, the thermal resistance of the rotor cores 112F and 112R is 0.04 K / W, and the magnitude of the thermal resistance of the coil bobbin 17 hinders heat dissipation. On the other hand, according to the present invention, the thermal resistance of the coil bobbin 17 can be suppressed to about 0.015 K / W, and the temperature rise of the field coil 12 can be sufficiently reduced.

  In the above-described embodiment, the high thermal conductive resin is used as the high thermal conductive material for forming the coil bobbin 17, but a metal can also be used. For example, the coil bobbin 17 is manufactured by die casting using aluminum or the like. In this case, it is necessary to treat the metal surface with an insulating coating in order to achieve electrical insulation. When formed in this way, the metal part has a very low thermal resistance, so the thermal resistance of the coil bobbin 17 is determined by the thermal resistance of the insulating coating part.

  In order to maintain insulation, if the thickness of the insulating coating is 50 μm, the thermal conductivity of the insulating coating is 0.2 W / m · K, and the thickness of the coil bobbin 17 is 1 mm, the metal part of the coil bobbin 17 and the insulating coating part The equivalent thermal conductivity is about 4 W / m · K. That is, as described above, if the thermal conductivity is 2 W / m · K or more, the temperature rise of the field coil 12 is suggested and the output of the vehicle alternator can be increased. The output of the vehicle alternator can be increased by using a coil bobbin 17 having a metal coated with an insulating coating.

-Second Embodiment-
FIG. 7 is a view showing a second embodiment of the present invention, and is a view showing a cross section of the rotor 112. In FIG. 7, only the upper part with respect to the central axis of the shaft 18 is shown. The configuration other than the rotor 112 is the same as that of the first embodiment described above. In the present embodiment, the shapes of the front-side rotor core 112F and the rear-side rotor core 112R formed of a magnetic material are different from the rotor cores 112F and 112R described in the first embodiment. Specifically, the disk portions 112b of the front rotor core 112F and the rear rotor core 112R are configured such that the axial thickness gradually increases in the outer diameter direction.

  That is, when the thickness of the portion of the disk portion 112b that contacts the shaft portion 112a is t1, and the thickness of the portion of the disk portion 112b that contacts the rotor claw magnetic pole 112c is t2, t1 <t2. Therefore, the surface of the disk portion 112 b to which the flange portion 172 of the coil bobbin 17 is in close contact is not perpendicular to the axis of the shaft 18 but is inclined. Therefore, the winding space of the field coil 12 surrounded by the body portion 171 and the flange portion 172 of the coil bobbin 17 has a trapezoidal cross-sectional shape, and becomes a shape that narrows with respect to the outer diameter direction. ing.

  On the other hand, in the rotor cores 112 </ b> F and 112 </ b> R shown in FIG. 3, the surface in close contact with the flange portion 172 is perpendicular to the axis of the shaft 18. By the way, the coil bobbin 17 tends to be deformed so that the whole expands in the outer diameter direction by the action of thermal expansion and centrifugal force. However, in the case of the structure shown in FIG. 3, the surface in close contact with the flange portion 172 is perpendicular to the axis of the shaft 18, so that the deformation of the coil bobbin 17 is prevented from the rotor cores 112 </ b> F and 112 </ b> R to the coil bobbin 17. It is difficult to act like this. As a result, the expansion of the coil bobbin 17 in the outer diameter direction cannot be suppressed, the adhesion between the body 171 of the coil bobbin 17 and the rotor core shaft 112a is lowered, and the heat dissipation from the field coil 12 may be reduced. There is.

  However, in the second embodiment, by adopting the configuration as shown in FIG. 7, even when the coil bobbin 17 expands due to heat or a centrifugal force acts on the coil bobbin 17, the rotor cores 112 </ b> F and 112 </ b> R and the coil bobbin It becomes possible to maintain the adhesiveness with 17. That is, even if the coil bobbin 17 is deformed so as to expand in the outer diameter direction due to the action of thermal expansion or centrifugal force, the surface of the disk portion 112b to which the flange portion 172 is in contact is slanted as shown in FIG. Therefore, expansion of the coil bobbin 17 is suppressed by the inclined surface, and adhesion between the coil bobbin 17 and the rotor cores 112F and 112R is not impaired. As a result, it is possible to prevent a decrease in heat dissipation from the field coil 12 to the rotor cores 112F and 112R due to a decrease in adhesion due to thermal expansion of the coil bobbin 17.

-Third embodiment-
Next, a third embodiment according to the present invention will be described with reference to FIGS. FIG. 8 is a diagram illustrating the flow of magnetic flux when a current flows through the field coil 12. When a direct current flows in the direction shown in FIG. 8 with respect to the field coil 12, the main magnetic flux is changed from the shaft part 112a of the rotor cores 112F and 112R to the disk part 112b and the rotor claw magnetic pole as shown by the thick solid lines in FIG. It flows into the stator 4 through 112c. The cross-sectional area in each path needs to be large enough to alleviate magnetic saturation.

  That is, it is desired to increase the dimensions B, C, and E in FIG. In FIG. 9, the dimension A is the outer radius of the rotor cores 112F and 112R, the dimension B is the outer radius of the shaft part 112a, the dimension C is the thickness of the disk part 112b, the dimension D is the axial length of the rotor cores 112F and 112R, and the dimension E is the rotor. This represents the radial thickness of the root portion of the claw magnetic pole 112c. The shaft 18 is also considered to constitute a part of the magnetic path.

  By the way, the alternating current generator for vehicles receives restrictions of an outer diameter and an axial length by the mounting property to a vehicle, and cannot change the dimension A and D. FIG. Therefore, increasing the dimensions B, C, and E to ensure a sufficient cross-sectional area means that the area around which the field coil 12 is wound is reduced.

  When the area where the field coil 12 is wound is reduced, it is necessary to select a conductor with a small wire diameter as the coil conductor of the field coil 12 in order to obtain the same magnetomotive force as the conventional one while maintaining the number of turns. is there. In that case, the winding resistance of the field coil 12 increases, and the Joule loss generated in the field coil 12 increases. As a result, a sufficient magnetomotive force cannot be obtained due to the temperature rise of the field coil 12, and an improvement in output cannot be expected.

  Therefore, if the coil bobbin 17 having a high thermal conductivity described in the first embodiment is used, the temperature rise of the field coil 12 can be suppressed. Therefore, the dimensions B, C, and E in FIG. 9 are sufficiently large. Thus, the magnetic saturation of the rotor cores 112F and 112R can be sufficiently relaxed. That is, the relaxation of the magnetic saturation of the rotor cores 112F and 112R and the suppression of the temperature rise of the field coil 12 can both be achieved, and the output can be improved as compared with the prior art.

  FIG. 10 shows the relationship between dimensions B, C, and E related to the cross-sectional area of the magnetic flux path and S representing the cross-sectional area of the coil winding region. In FIG. 10, 2C / D on the horizontal axis represents the ratio of the thickness 2C of the disk portion 112b that combines the front side and the rear side to the rotor axial direction dimension D. On the other hand, (B + E) / A on the vertical axis represents the ratio of the sum of the radius B of the shaft portion 112 a and the radial thickness E of the rotor claw magnetic pole 112 c to the outer radius A of the rotor 112.

  The value of the cross-sectional area S of the field coil housing space depends on the dimensions C, B, and E, and a plurality of curves (S = 0.9, S = 0.6,..., S shown in FIG. = Curve represented by 0.3) Contour lines connecting the same cross-sectional areas S are shown. The cross-sectional area S decreases as it goes to the right side of the horizontal axis, and decreases as it goes to the upper side of the vertical axis. Here, S is normalized by a certain value.

  First, from the viewpoint of relaxing the magnetic saturation of the rotor cores 112F and 112R, the dimensions B, C, and E are set so as to satisfy (B + E) / A> 0.8 and 2C / D> 0.55. There is a need to. However, in the conventional rotor configuration, when such dimensions B, C and E are set, the cross-sectional area S at that time is 0.5 to 0.6 from FIG. When the wire diameter of the coil 12 is set, the winding resistance becomes too large, and a sufficient magnetomotive force cannot be obtained due to the temperature rise of the field coil 12. For this reason, conventionally, (B + E) /A≈0.8 and 2C / D≈0.52 are set. However, in this case, magnetic saturation becomes a problem, and an improvement in output cannot be expected.

  Here, when the coil bobbin 17 having high thermal conductivity described in the first embodiment is applied, the temperature rise of the field coil 12 can be suppressed. The winding resistance at can be suppressed to the same level as in the past. That is, the cross-sectional area S can be made smaller than before. Therefore, (B + E) / A> 0.8 and 2C / D> 0.55 are configured so that the magnetic saturation is sufficiently relaxed, and the temperature rise of the field coil 12 can be suppressed. Thus, the output is not reduced due to the temperature rise.

  When the dimensions B, C, and E are set, it is necessary to secure a space enough for the field coil 12 to be wound, and at least about S = 0.3 is required. Here, when the coil bobbin 17 described in the first embodiment is employed, the cross-sectional area S can be reduced to about S = 0.3. That is, since the temperature rise can be suppressed even if the wire diameter of the field coil 12 is reduced, a space for winding the field coil is secured if S = 0.3. Therefore, as can be seen from FIG. 10, in a range of 0.8 <(B + E) / A <0.84 and 0.55 <2C / D <0.70 (region surrounded by a broken line in FIG. 10). If selected, it is possible to achieve both magnetic saturation and a space for winding the field coil.

  Each of the embodiments described above may be used alone or in combination. This is because the effects of the respective embodiments can be achieved independently or synergistically. In addition, the present invention is not limited to the above embodiment as long as the characteristics of the present invention are not impaired.

  4: Stator, 5: Stator winding, 12: Field coil, 17: Coil bobbin, 18: Shaft, 21: Stator core, 100: AC generator for vehicle, 112: Rotor, 112a: Shaft, 112b : Disk part, 112c: rotor claw magnetic pole, 112F: front rotor core, 112R: rear rotor core, 171: trunk part, 172: flange part

Claims (6)

A Landel-type rotor core having a shaft portion, a pair of disk portions extending in the outer diameter direction from both axial ends of the shaft portion, and a plurality of claw magnetic pole portions formed so as to extend from the disk portion in the axial direction;
A coil bobbin having a body part extrapolated to the shaft part, and a pair of flange parts extending in the outer diameter direction from both ends of the body part along the disk part;
A field coil wound around the body of the coil bobbin;
An automotive alternator comprising: a stator having an iron core that is disposed so as to surround the outer periphery of the claw magnetic pole portion of the rotor core and around which an armature coil is wound,
An AC generator for a vehicle, wherein the thermal conductivity of the coil bobbin is set so that the thermal conductivity of the coil bobbin is larger than the thermal conductivity of the field coil. In the vehicle alternator according to claim 1,
The vehicle bobbin characterized in that the coil bobbin is formed of a resin material containing a metal filler so that the thermal conductivity of the coil bobbin is 2.0 W / m · K or more and 15.0 W / m · K or less. Generator. In the vehicle alternator according to claim 1,
An AC generator for a vehicle, wherein the coil bobbin is formed of a metal whose surface is subjected to insulation treatment so that the coil bobbin has a thermal conductivity of 2.0 W / m · K or more. In the vehicle alternator according to any one of claims 1 to 3,
The outer radius A of the rotor core, the outer radius B of the shaft portion of the rotor core, and the radial thickness E of the root portion of the claw magnetic pole portion extending in the axial direction from the disk portion satisfy (B + E) / A> 0.80. AC power generation for vehicles, wherein the ratio 2C / D between the axial thickness C of the disk portion of the rotor core and the axial length D of the rotor core satisfies 2C / D> 0.55 Machine. In the vehicle alternator according to claim 4,
AC for vehicles, characterized in that the value of (B + E) / A is 0.8 <(B + E) / A <0.84 and the value of 2C / D is 0.55 <2C / D <0.70 Generator. In the vehicle AC generator according to any one of claims 1 to 5,
The axial thickness of the disk portion extending in the outer diameter direction from both ends of the shaft portion is thicker toward the outer diameter side so that the distance between the pair of disk portions becomes smaller toward the outer diameter side. AC generator for vehicles.

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