JPH0652373U - Brushless alternator - Google Patents

Abstract

(57) [Summary] [Purpose] Mold the rotor core into an aluminum casting with a fan. A front rotor core 22 and a rear rotor core 23, which are magnetized in opposite polarities, are molded in a state in which they mesh with a non-magnetic cylindrical body 24 made of aluminum casting with a predetermined gap, and both rotor cores 22 and 23 are magnetically coupled. The non-magnetic cylindrical body 24 is integrated with the front fan 25 and the rear fan 26 on the end surface of the non-magnetic cylindrical body 24.
Non-magnetic cylindrical body with fan 2 by integrally molding
4, the rotor 27 in which the rotor cores 22 and 23 are molded is completed by one casting process, and the manufacturing process is simplified.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a brushless AC generator in which a rotor core is molded in an aluminum casting with a fan.

[0002]

[Prior art]

 The alternator for vehicles has been continuously improved with the aim of downsizing and speeding up.In order to improve cooling efficiency in consideration of safety, an internal fan-shaped structure in which fans are arranged at both ends of the rotor Is becoming mainstream. In the case of brushless AC generators, a front rotor core and a rear rotor core are integrally welded to a non-magnetic space ring, and a press-molded fan is spot welded to both ends of the space ring, which is generally used for vehicles. There is.

The brushless AC generator 1 shown in FIG. 8 is for a vehicle such as an automobile, and the bearings 3 and 4 assembled on the front surface and the back surface of the casing 2 rotate the rotor shaft near the tip and the rotor shaft respectively. The engine power is transmitted by belt transmission to a pulley 6 fixed to the tip of a rotor shaft 5 that extends freely from the front surface of the casing 2 and that rotates the rotor 7 to generate electricity. . In the rotor 7, that is, the rotor, for example, the front rotor core 8 magnetized to the N pole is fitted to the rotor shaft 5, and the rear rotor core 9 magnetized to the S pole is inserted through the non-magnetic space ring 10 to the front rotor core. It is configured by being integrated with 8. As shown in FIGS. 9 and 10, the front rotor core 8 and the rear rotor core 9, which are magnetized to have mutually different polarities, respectively, have a plurality of claw portions axially protruding along the circumference at equal intervals. The 8a and 9a are meshed with each other by making the phases different from each other by a predetermined angle so that the N poles and the S poles are alternately arranged in a ring shape. However, even if it is said to be meshed, one claw portion, for example, 8a is separated from the other so that the claw portions 8a and 9a are not brought into close contact with each other but the N pole and S pole claw portions 8a and 9a are separated by a predetermined gap. A structure is employed in which a pair of adjacent claw portions 9a, 9a are loosely fitted. That is, the front rotor core 8 and the rear rotor core 9 are integrated with each other via the space ring 10 made of a non-magnetic material and are magnetically insulated from each other. The space ring 10 has a cylindrical shape and is press-fitted into the inner peripheral surface of the claws 8a and 9a of the rotor cores 8 and 9 by press fitting. The space ring 10 was fixed by welding (hatched portion in FIG. 10).

The stator 11, which is a stator, is fixed to the inner peripheral surface of the casing 2, and the stator winding 12 faces the rotating surfaces of the front and rear rotor cores 8 and 9. The rotor 7 has a cage shape as a whole, and a cylindrical field winding 13 is loosely inserted inside the cage at a position facing the stator 11 with the rotor cores 8 and 9 interposed therebetween. The field winding 13 is held by a rear bracket 14 which is bolted and fixed to the back surface of the casing 2, and exerts a constant magnetic field on the rotating surface of the rotor 7. Therefore, in the magnetic field formed by the field winding 13, the rotor cores 8 and 9 of the N pole and the S pole rotate while crossing the magnetic lines of force, whereby a cross magnetic field acts on the stator winding 12 and an alternating current is generated. Be induced. The induced alternating current is guided to the power supply terminal 16 via the lead wire 15 extending from the stator winding 12.

Further, since the stator winding 12 generates heat due to the induced alternating current, a multi-blade fan formed by press molding on both end surfaces of the rotor 7 so that the inside of the casing 2 including other heat generating points can be efficiently cooled. 17 and 18 are spot welded. Both the front side fan 17 and the rear side fan 18 are formed by cutting and raising blades 17a, 18a in a ring-shaped plate material having an outer diameter similar to that of the rotor 7, as shown in FIGS. In addition, spot welding is performed on the end faces of the rotor cores 8 and 9 corresponding to a plurality of points. 17b and 18b indicate spot welding points of the fans 17 and 18, respectively.

[0006]

[Problems to be solved by the device]

 However, in the conventional brushless AC generator 1, the front rotor core 8 and the rear rotor core 9 magnetized to have different polarities are fixed to each other by welding the claw portions 8a and 9a to the space ring 10, respectively. For this reason, it takes a considerable amount of time to assemble the front and rear rotor cores 8 and 9, and if the shaft cores of the rotor cores 8 and 9 shift during welding, the dynamic balance of the completed rotor 7 will be impaired. There were problems such as a decrease in power generation efficiency and easy promotion of uneven wear of the bearings 3 and 4. Similarly, since the front side fan 17 and the rear side fan 18 are also fixed to the end faces of the rotor cores 8 and 9 by spot welding, a large number of spot welding points 17b and 18b are required on the front side and the rear side. However, the complexity of the manufacturing process is unavoidable in terms of man-hours, and the effect of good or bad welding on the dynamic balance of the rotor 7 cannot be ignored. Therefore, careful welding was required, and the process control was strict.

Further, the winds generated by the fans 17 and 18 provided on both end faces of the rotor 7 are blown in a relatively large amount to the portions near both ends of the stator winding 12, but near the center of the stator winding 12. Is weaker than both ends. This is because the field winding 13 is fixed to the rear bracket 14, and the inner diameter of the rear fan 18 is limited by the outer diameter of the field winding 13. Since the outer diameters of the blades 17a and 18a on both the front side and the rear side are limited by the inner diameter of the stator winding 12, the blade area is inevitably limited, and the blades implanted on the outer peripheral surface of the rotor 7 are tentatively limited. It is possible to improve the cooling efficiency if a fan with a fan can be assembled. However, the conventional method of fixing the press-molding fan by spot welding leaves little room for such improvement. was there.

Therefore, an object of the present invention is to easily assemble the rotor cores on the front and rear sides, and simultaneously to integrally mold the fans on the front and rear sides to reduce the number of manufacturing steps. is there.

[0009]

[Means for Solving the Problems]

 In order to achieve the above object, the present invention is a brushless AC generator in which a rotor with a core rotates in a magnetic field formed by a field winding and induces an alternating current in a stator winding, which are magnetized to have opposite polarities. The front rotor core and the rear rotor core are molded in a state of meshing with each other with a predetermined gap, and the rotor cores are magnetically insulated and integrated with each other, and the non-magnetic cylindrical body is integrated with at least one end surface of the non-magnetic cylindrical body. The object is achieved by providing a brushless AC generator having a molded front side fan or rear side fan.

In order to achieve the above-mentioned object, the present invention is characterized in that a fan is provided on the outer peripheral surface of the non-magnetic cylinder, and the non-magnetic cylinder is made of aluminum casting. It is characterized by having done.

[0011]

【Example】

 An embodiment of the present invention will be described below with reference to FIGS. 1 is a longitudinal sectional view showing an embodiment of the brushless AC generator of the present invention, FIGS. 2 and 3 are side views and partially enlarged side views of the rotor shown in FIG. 1, and FIGS. FIG. 3A is a front view and a rear view of the rotor shown in FIG. 2, respectively.

In a brushless AC generator 21 shown in FIG. 1, a front rotor core 22 and a rear rotor core 23, which are magnetized in opposite polarities, are molded into a non-magnetic cylindrical body 24 made of a non-magnetic aluminum casting, and a predetermined shape is obtained. The front side fan 25 and the rear side fan 26 are integrally molded on both end surfaces of the non-magnetic cylindrical body 24 during the molding. The non-magnetic cylindrical body 24 corresponds to the conventional non-magnetic space ring 10 as shown by hatching in FIGS. 1, 2, and 3. However, the conventional non-magnetic space ring 10 has the front-side rotor core. 8 and the rear side rotor core 9 are integrated by welding the claw portions 8a, 9a to each other, but here, the rotor cores 22, 23 are molded when casting into an aluminum casting. , 23 and fans 25, 26 can be manufactured at once by a single casting process.

As shown in FIGS. 4 and 5, the front-side fan 25 shown in the embodiment is a radial fan in which twelve blades 15 a extend straight in the radial direction, and the rear-side fan 26 also includes a fan 12. Each of the blades 26a is a radial fan that extends straight in the radial direction. That is, the blades 25a and 26a of the fans 25 and 26 can send the air mainly in the radial direction rather than the axial direction, and actively cools the stator winding 12, which is the most easily heated portion. be able to.

As described above, the brushless AC generator 21 differs from the conventional brushless AC generator 1 in which the rotor cores 8 and 9 are fixedly welded to the non-magnetic space ring 10 to the rotor cores 8 on the front and rear sides. 9 does not require a step for welding and fixing 9 and a step for spot welding the front and rear fans 17 and 18, and the fans 25 and 26 are attached to the non-magnetic cylindrical body 24 when the rotor cores 22 and 23 are molded. Since the rotor 27 is formed as a single body, the rotor 27 can be completed in a single casting process, which can significantly reduce the number of steps. In addition, by improving the casting precision, manufacturing defects such as misalignment of the shaft cores of the rotor cores 22 and 23 and deviation of the fans 25 and 26 can be accurately eliminated. It is possible to improve the power generation efficiency and the cooling efficiency to the utmost and to prevent uneven wear of the bearings 3 and 4 to enhance the durability.

Further, in the embodiment, since the non-magnetic cylindrical body 24 is made of aluminum casting, the front rotor core 22 and the rear rotor core 23 can be magnetically insulated and firmly integrated, and Since aluminum is a lightweight and highly rigid metal material, it does not add much weight to the rotor. Moreover, since the aluminum casting technology, which has made remarkable progress in recent years, can be used for casting without forming cavities inside the casting, it is possible to manufacture a rotor 27 that is uniform and has a high dimensional accuracy. The front and rear rotor cores 22 and 23 can be accurately maintained in a predetermined positional relationship, the rotor 27 can be smoothly rotated with excellent dynamic balance, and the power generation efficiency can be increased.

In the above embodiment, the fan 25, 26 is a radial fan in which the blades 25a, 26a extend straight in the radial direction. However, the fan may have a curved shape such as a spiral shape. For example, as shown in FIG. 6, the rearward-facing fan 31 in which the blades 31a are spirally curved so as to flow rearward in the rotation direction of the rotor, and as shown in FIG. 7, each blade 41a has a small area, It is also possible to use a multi-blade fan 41 or the like in which a large number of blades 41a are circumferentially arranged in close proximity.

[0017]

[Effect of device]

 As described above, according to the present invention, the front rotor core and the rear rotor core, which are magnetized in opposite polarities, are molded into a non-magnetic cylindrical body in a meshed state with a predetermined gap, and both rotor cores are magnetically coupled. The rotor core is welded and fixed to the non-magnetic space ring because the fan is formed by integrally molding the non-magnetic cylindrical body and the front side fan or the rear side fan on at least one end surface of the non-magnetic cylindrical body. Unlike the conventional brushless alternator, the manufacturing process for welding and fixing the rotor cores on the front and rear sides and the manufacturing process for spot welding the fans on the front and rear sides are unnecessary. Since the fan is formed integrally with the non-magnetic cylinder when the rotor core is molded, the rotor can be completed in a single casting process. It is possible to drastically reduce man-hours, and by improving the casting accuracy, it is possible to accurately eliminate manufacturing defects such as misalignment of the rotor core axis lines and fan deviations, and to create a rotor with excellent dynamic balance. By manufacturing, the power generation efficiency and the cooling efficiency can be enhanced as much as possible, and the uneven effect of the bearing can be prevented to improve the durability.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of a brushless AC generator of the present invention.

FIG. 2 is a side view of the rotor shown in FIG.

3 is a partially enlarged side view of the rotor shown in FIG.

FIG. 4 is a front view of the rotor shown in FIG.

FIG. 5 is a rear view of the rotor shown in FIG.

FIG. 6 is a front view showing a modified example of a fan portion of the brushless AC generator of the present invention.

FIG. 7 is a front view showing another modification of the fan portion shown in FIG.

FIG. 8 is a vertical sectional view showing an example of a conventional brushless AC generator.

9 is a side view of the rotor shown in FIG.

10 is a partially enlarged side view of the rotor shown in FIG.

11 is a front view of the rotor shown in FIG.

12 is a rear view of the rotor shown in FIG.

[Explanation of symbols]

 21 Brushless AC Generator 22 Front Side Rotor Core 23 Rear Side Rotor Core 24 Non-Magnetic Cylindrical Body 25 Front Side Fan 26 Rear Side Fan 27 Rotor

Claims (3)

[Scope of utility model registration request] 1. A brushless AC generator in which a rotor with a core rotates in a magnetic field formed by a field winding to induce an alternating current in a stator winding, the front rotor core and the rear rotor core being magnetized in opposite polarities. A non-magnetic cylindrical body in which the rotor cores are integrally formed in a magnetically insulated state, and a front side fan or a rear side integrally molded on at least one end surface of the non-magnetic cylindrical body. A brushless AC generator comprising a fan. 2. The brushless AC generator according to claim 1, wherein the non-magnetic cylindrical body has a fan on an outer peripheral surface thereof. 3. The brushless AC generator according to claim 1, wherein the non-magnetic cylindrical body is an aluminum casting.