JPH0427790B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a claw-type alternator having a rotor in which two rotor cores each having a plurality of claw portions are assembled to face each other, and particularly to a vehicle. The present invention relates to a method for manufacturing a rotor core for a claw-type alternator for ships.

[Background of the invention]

As shown in FIG. 1, the rotor of this type of claw-shaped alternator includes a boss portion 2 formed in the center, a connecting plate portion 3 projecting radially from one end of the boss portion 2, and a connecting plate portion 3 extending radially from one end of the boss portion 2. Connecting plate part 3 parallel to the center line of part 2
Generally, the rotor core 1 is constructed by combining two rotor cores 1 each having a plurality of claws 4 protruding from the outer end thereof. In the two rotor cores 1, the respective boss portions 2 are joined in a mutually opposing state, and the mutual claw portions 4 are
They are assembled so as to be inserted into the valleys between the claws 4, and on the other hand, a field winding 5 is disposed on the outer periphery of the boss 2, and a rotating shaft 7 is fitted and fixed in the shaft hole 6. It is something that will be done.

In the rotor configured as described above, each claw portion 4 of each rotor core 1 alternately forms different poles in the circumferential direction when the field winding 5 is excited. When this rotates, it applies a rotating magnetic field to the armature disposed around its outer periphery.

Conventionally, methods for manufacturing this type of rotor core include hot forging, cold forging, and sheet metal bending, and the manufacturing process for each has been developed independently. The cold forging method requires strong pressure and has problems with molds, and the sheet metal bending method has a large material loss during blanking, resulting in poor yields. Although the hot forging method considerably improves the material yield, it is difficult to obtain the required tolerances for the shaft hole drilling and respective surface finishes after forging, and many cutting processes are required. be. Although this method involves a large number of cutting steps, which has contributed to a large amount of manufacturing costs, it is indispensable for ensuring the quality of the rotor core, and each method has its own advantages and disadvantages.
There are many problems from the standpoint of resource and energy conservation, as well as from the standpoint of reducing the number of processing steps.

[Summary of the invention]

The present invention solves the manufacturing problems of the rotor core as described above, and uses three methods to manufacture the rotor core with sufficient accuracy at low cost: hot forging, cutting, and cold forging. This is based on the establishment of a combination technology, and the gist of its structure is that a central boss part, a plurality of claw connecting plate parts, and a plurality of parts are shaped into a predetermined size and shape by hot forging a predetermined volume of material. After obtaining the shaped product, the forging burrs generated near the outer periphery of the connecting plate of the roughly shaped product are removed, and the roughly shaped product from which the forging burrs have been removed is shaped to approximate the dimensions and shape of the finished product. The compacted product is compressed, then slowly cooled, and then the compacted product is pressure-adjusted to a predetermined size by cold forging, and the variation in volume of the compacted compact is made uniform by cutting, and then cold forged to make the volume uniform. This is a method for manufacturing a rotor core for a claw-shaped alternating current generator in which a product with precise predetermined dimensions and shape is obtained by regulating the pressure.

[Embodiments of the invention]

An embodiment of the present invention will be described below based on the drawings.

FIGS. 2 to 7 sequentially show the steps of this embodiment.

First, as shown in FIG. 2, a round steel is press-cut to a predetermined size to form a material 8 having a predetermined capacity. It is preferable that the capacity of the material 8 is as accurate as possible in order to minimize material loss and facilitate post-processing. There are various types of round steel that can be used, but in general, it must be a low-carbon material and a magnetic material suitable for the rotor core of a claw-shaped alternator.

There is nothing different from the conventional method.

Next, the raw material 8 is hot-forged to form a rotor core having a predetermined size and shape, including the boss portion 2a, the connecting plate portion 3a, and the claw portion 4a. It is preferable that this size and shape be as close as possible to the finished product.
Note that no shaft hole is formed in the boss portion 2a in this step. Further, in this step, the excess capacity of the material 8 becomes a forging burr 9 and appears near the outer periphery of the connecting plate portion 3a.

Therefore, in the next step, the forging burr 9 of the above-mentioned roughly shaped product is removed. This is done using standard punching methods.
FIG. 4 shows a roughly shaped product from which the forging burr 9 has been removed.

Thereafter, the roughly shaped product from which the forging burrs 9 have been removed is shaped and pressed to make it even closer to the required dimensions and shape of the finished product, and then slowly cooled. FIG. 5 shows the generally shaped product after the above-mentioned shaping and pressurization. For the above-mentioned shaping pressure, a general corresponding press is used. The slow cooling can be carried out by leaving the shaped product to cool naturally after the hot forging step. This slow cooling provides an annealing effect without going through a special annealing step, and provides a favorable effect in subsequent steps.

After completion of slow cooling, the above-mentioned roughly shaped product is subjected to cold forging to adjust the pressure of the inner diameter, outer diameter, and connecting plate portion.

Further, the pressure-regulated general-shaped product is cut into a rough finish to have a predetermined capacity required in the next process. As shown in FIG. 6, the cutting process is performed on the shaft hole 6c, the outer bottom surface of the connecting plate portion 3c, the outer periphery and height of the claw portion 4c, and the boss portion 2c.

This differs from the extremely high-precision cutting performed in the conventional example described above, and is performed with the main purpose of obtaining a predetermined capacity required in the next process as described above, so it is much easier to cut. It is processing.

Finally, the roughly shaped product that has undergone the above cutting process is pressure-regulated by cold forging, and is precisely formed into a rotor core with predetermined dimensions.

As shown above, this embodiment includes a step of hot forging the material 8 to form the outline of the rotor core, a step of cutting the roughly shaped product to a predetermined capacity after slow cooling, and a step of cutting the material 8 to a predetermined capacity after the cutting. It consists of the process of obtaining a finished product by cold forging, and in the process from hot forging to completion of slow cooling, it is possible to obtain an outline that is very close to that of the finished product, as well as to make the material structure uniform, and the next cutting process. Since the capacity in the process can be adjusted to the appropriate value required in the next process, pressure can be applied with less energy in the final cold forging process, and a highly precise product can be obtained. Further, since the above-mentioned cutting process only requires rough finishing, it is much easier than the difficulty of the cutting process in the conventional example described above.

〔Effect of the invention〕

Therefore, as can be fully understood from the description of the embodiments above, the present invention can fully achieve the intended purpose.

[Brief explanation of drawings]

Fig. 1 is a partial sectional view showing a rotor of a known alternator, Figs. 2 to 7 show the steps of an embodiment of the present invention, and Fig. 2 shows a cut material. A perspective view, FIG. 3a is a plan view showing a roughly shaped product obtained by hot forging the material, FIG. 3b is a sectional view taken along line A-A, and FIG. FIG. 4b is a plan view showing the removed state, FIG. 4b is a sectional view taken along the line B-B, FIG. -C
Fig. 6a is a bottom view showing the state after cutting, Fig. 6b is a sectional view taken along line D-D, Fig. 7
Figure a is a plan view showing the finished product after final cold forging;
FIG. 7b is a sectional view taken along the line E-E. 1... Rotor core, 2, 2a, 2b, 2c...
Boss portion, 3, 3a, 3b, 3c...connecting plate portion,
4, 4a, 4b, 4c...Claw portion, 5...Field winding, 6,6c...Shaft hole, 7...Rotating shaft, 8
...Material, 9...Forged burr.

Claims (1)

[Claims] 1. A product having a central boss portion, a plurality of connecting plate portions, and a plurality of claw portions formed into a predetermined size and shape is obtained by hot forging a material having a predetermined capacity, and then the above-mentioned Forging burrs generated near the outer periphery of the connecting plate portion of the roughly shaped product are removed, and the roughly shaped product from which the forging burrs have been removed is shaped and pressurized to approximate the dimensions and shape of the finished product, then slowly cooled, and then the roughly shaped product is The product is pressurized to predetermined dimensions by cold forging, and the volume variation of the pressurized general product is made uniform by cutting, and then the pressure is reduced by cold forging to produce a product with precise predetermined dimensions and shape. A method for manufacturing a rotor core for a claw-shaped alternator.