Rotor manufacturing method

A rotor manufacturing apparatus includes a pusher and multiple blades. The pusher presses multiple magnets that are temporarily attached to a rotor core and arranged side by side in a circumferential direction of the rotor core from an outer side in a radial direction of the rotor core. The multiple blades are individually inserted into gaps between the magnets pressed by the pusher.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present disclosure contains subject matter related to that disclosed in Japanese Priority Patent Application JP 2012-062148 filed in the Japan Patent Office on Mar. 19, 2012, the entire contents of which are hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

An embodiment disclosed herein relates to a rotor manufacturing apparatus, a rotor manufacturing method, and a permanent-magnet positioning method.

2. Description of the Related Art

A rotor of a rotating electrical machine having multiple permanent magnets attached to the circumferential surface of the rotor core is known to date. Preferably, the permanent magnets for such a rotor are disposed at equal intervals on the circumferential surface of the rotor core so that the magnetic flux is concentrated at a center portion between magnetic poles.

In view of this, a rotor is developed in which multiple axially-extending protrusions are disposed at equal intervals on the circumferential surface of the rotor core and permanents magnets are positioned by moving the permanent magnets along the side surfaces of the protrusions, and a method of manufacturing the rotor is developed (see Japanese Unexamined Patent Application Publication No. 2011-120328, for example).

When, for example, the rotor core is a multi-layer core obtained by stacking annular magnetic steel sheets, the above-described axially extending protrusions are formed by stacking protrusions formed on the outer circumference of the magnetic steel sheets.

SUMMARY OF THE INVENTION

A rotor manufacturing apparatus according to an aspect of the embodiment includes a pressing portion and multiple blade portions. The pressing portion presses a plurality of permanent magnets that are temporarily attached to a rotor core and arranged side by side in a circumferential direction of the rotor core from an outer side in a radial direction of the rotor core. The plurality of blade portions are individually inserted into gaps between the permanent magnets pressed by the pressing portion.

DESCRIPTION OF THE EMBODIMENTS

Referring to the attached drawings, a rotor manufacturing apparatus, a rotor manufacturing method, and a permanent-magnet positioning method according to an embodiment of the disclosure are described in detail below. Note that the embodiment disclosed below does not limit the invention.

Description will be given below by taking a case of manufacturing a small rotor that is mounted on a small motor as an example. Hereinbelow, permanent magnets attached to the circumferential surface of a rotor core will be described as “magnets”, which are segment magnets obtained by segmentation.

For easy description, some drawings used in the following description have a three-dimensional orthogonal coordinate system including the Z axis whose orientation vertically upward is regarded as a positive direction and whose orientation vertically downward (that is, a vertical direction) is regarded as a negative direction.

Also for easy description below, in the case of describing multiple identical components, only one of the multiple components may be denoted by a reference symbol and the others may not be. In that case, the one component denoted by the reference symbol and the other components are regarded as having the same configuration. The arrows indicating the movement of each component will be denoted or not be denoted in the same manner.

Before describing the rotor manufacturing apparatus according to the embodiment, description will be first given on a schematic procedure using the rotor manufacturing apparatus in an upstream process.FIG. 1AtoFIG. 1Care (first to third) schematic diagrams of the schematic procedure in the upstream process.

As illustrated inFIG. 1A, a rotor core1is formed into a substantially columnar shape integrally including a shaft, which is a rotation shaft, by performing cutting using a lathe or by other ways. The rotor core1includes recesses3and a protrusion4that extend throughout the circumference.

As illustrated inFIG. 1B, an adhesive ad is applied to the rotor core1by a device such as an application device, which is not illustrated. The adhesive ad is applied to a predetermined portion of each recess3. From the view point of the strength or heat resistance, a thermosetting adhesive is used as an example of the applied adhesive ad.

As illustrated inFIG. 1C, magnets M are attached to the rotor core1by a device such as an attaching device, which is not illustrated. The attachment here is a “temporary attachment” of the magnets M. In the rotor manufacturing apparatus according to the embodiment, these “temporarily attached” magnets M are individually positioned at appropriate circumferential positions such that the magnetic flux is concentrated at a center portion between magnetic poles.

FIG. 1AtoFIG. 1Cillustrate the case where the magnets M are attached to the circumferential surface of the rotor core1at two levels in the axial direction (that is, in the direction in which the shaft2extends). The protrusion4illustrated inFIG. 1Ais a portion that positions the magnets M in the axial direction of the rotor core1in the above case.

Hereinbelow, a configuration and an operation of the rotor manufacturing apparatus according to the embodiment will be specifically described.FIG. 2AandFIG. 2Bare (first and second) schematic diagrams of a configuration and an operation of a rotor manufacturing apparatus10according to the embodiment when viewed from above.

As illustrated inFIG. 2A, the rotor manufacturing apparatus10includes pushers11(pressing portions). The number of pushers11corresponds to the number of magnets M. The pushers11are radially arranged. The pushers are driven independently of one another by individual air cylinders or other devices.

As illustrated inFIG. 2A, the pushers11press the magnets M (seeFIG. 1C) that have been temporarily attached in the upstream process from the radially outer side toward the circumferential surface of the rotor core1(see the arrow101ofFIG. 2A). Here, the pushers11press the magnets M with such a pressing force as to temporarily press the magnets M (a first pressing force).

Hereinbelow, a gap between two magnets M will be called a “magnet gap” and denoted by the reference symbol “Mi” as illustrated inFIG. 2A.

As illustrated inFIG. 2B, the rotor manufacturing apparatus10includes blades12(or blade portions). The number of blades12corresponds to the number of magnet gaps Mi and the blades are also arranged radially. As in the case of the pushers11, the blades are driven independently of one another by individual air cylinders or other devices.

As illustrated inFIG. 2B, the blades12are inserted into the magnet gaps Mi while the magnets M are pressed by the pushers11with such a magnitude of force as to temporarily press the magnets M (see the arrow102ofFIG. 2B).

Here, positioning of the magnets M performed by inserting the blades12will be described in detail.FIG. 3Aschematically illustrates positioning of the magnets M. For easy understanding,FIG. 3Aexcludes illustration of the pushers11that press the magnets M.

The axis RD illustrated inFIG. 3Ais an axis representing one radial direction extending from the rotation center C of the shaft2. Although the blade12and a blade that is adjacent to the blade12are the same components, the adjacent blade is denoted by “12′” in order to be distinguished from the blade12.

As illustrated inFIG. 3A, the blade12has an end face (hereinafter referred to as a “straight face”)12aand a tapered face12bat its tip end portion, the end face12abeing substantially parallel to the axis RD and intersecting with the circumferential direction of the rotor core1, the tapered face12bobliquely intersecting with the axis RD.

When the blade12is inserted into the magnet gap Mi (see the arrow102ofFIG. 3A), the blade12causes the magnet M that comes into contact with the tapered face12bto move along the tapered face12b. In other words, the blade12shifts the magnet M in the circumferential direction of the rotor core1(see the arrow103ofFIG. 3A), and thus the magnet M is pressed against the straight face12aof the blade12′ (see the arrow104ofFIG. 3A).

Consequently, the magnet M is positioned at a predetermined position by using the straight face12aof the blade12′ as a standard surface B. Here, all the temporarily attached magnets M that are arranged side by side in the circumferential direction of the rotor core1are positioned simultaneously.

Thus, at least one side of each magnet M, is shifted to the predetermined position determined by the corresponding standard surface B even if the magnet M has a dimensional error. Consequently, the magnetic flux can be concentrated at a center portion between the magnetic poles.

FIG. 3Aillustrates the blade12having the straight face12aand the tapered face12b, but this is not the only limitation. A modification will be described with reference toFIG. 3B.

FIG. 3Bis a schematic diagram of a configuration of a blade12A according to the modification. As illustrated inFIG. 3B, a blade12A having tapered faces12Ab that individually come into contact with adjacent two magnets M may be used.

In this case, the inserted blade12A (see the arrow102A ofFIG. 3B) moves the magnets M in the left and right directions indicated by the arrows103A. Here, adjacent other blades12A (not illustrated) also apply similar forces to move the magnets M. Thus, with the equilibrium of the forces, the magnets M can be positioned at predetermined positions.

Description of the configuration and the operations of the rotor manufacturing apparatus10according to the embodiment is continued.FIG. 4Ais a (third) schematic diagram of a configuration and an operation of the rotor manufacturing apparatus10according to the embodiment when viewed from above.FIG. 4Bschematically illustrates a recess3of the rotor core1in an enlarged manner.

As illustrated inFIG. 4A, the rotor manufacturing apparatus10further presses the magnets M, which have been pressed against the blades12or whose positions on the circumference of the rotor core1are determined, using the pushers11toward the circumferential surface from the radially outer side of the rotor core1(see the arrow105ofFIG. 4A).

Here, as illustrated inFIG. 4B, the magnet M is further pressed with a predetermined force (a second pressing force), which is larger than the first pressing force and which is preadjusted to such a magnitude that the film thickness of the adhesive ad applied to the recesses3becomes uniform when the adhesive ad is pressed by the magnet M. Making the film thickness of the adhesive ad uniform in this manner improves the adhesion of the adhesive ad. Hereinbelow, pressing with the second pressing force is also referred to as “applying pressure”.

Subsequently, the rotor manufacturing apparatus10withdraws the blades12and allows the pushers11to operate.FIG. 5AandFIG. 5Bare (fourth and fifth) schematic diagrams of a configuration and an operation of the rotor manufacturing apparatus10according to the embodiment when viewed from above.

As illustrated inFIG. 5A, before the rotor manufacturing apparatus10performs the above operation, the magnets M may be fastened by a fastening member100or another device.

The use of such a device prevents the positioned magnets M from slipping down due to their weight before the adhesive ad cures. Hereinbelow, description will be given on the assumption that the magnets M are fastened by the fastening member100.

As illustrated inFIG. 5A, the rotor manufacturing apparatus10withdraws the blades12before withdrawing the pushers11(see the arrow106ofFIG. 5A). In other words, the blades12are withdrawn while the pushers11are pressing and holding the magnets M from the radially outer side of the rotor core1. Thus, even though the blades12are asynchronously withdrawn, the magnets M are prevented from moving in the circumferential direction.

As illustrated inFIG. 5B, after withdrawing the blades12, the rotor manufacturing apparatus10stops applying pressure to the magnets M by allowing the pushers11to operate (see the arrow107ofFIG. 5B).

In this manner, a series of processes (seeFIG. 2AtoFIG. 5B) of the rotor manufacturing apparatus10are completed. As illustrated inFIG. 1AtoFIG. 1C, in the case where the magnets M are attached to the circumferential surface of the rotor core1at multiple (two, for example) levels, the above-described series of processes is repeated for each level.

As illustrated inFIG. 6, the rotor manufacturing apparatus10hands over the rotor core1in which the magnets M are positioned and fastened by the fastening member100to a downstream process as a processed product.

In the downstream process, if, for example, the adhesive ad is a thermosetting adhesive, a heating process or the like is performed to set the adhesive ad (seeFIG. 4B).

Now, the procedure of processes performed by the rotor manufacturing apparatus10described thus far will be shown.FIG. 7is a flowchart of the procedure of the processes performed by the rotor manufacturing apparatus10.

As illustrated inFIG. 7, first, the rotor manufacturing apparatus10temporarily presses the temporarily attached magnets M using the pushers11from the radially outer side to the circumferential surface of the rotor core1(Step S101).

The rotor manufacturing apparatus10then inserts the blades12into the corresponding magnet gaps Mi (Step S102).

Then, using the pushers11, the rotor manufacturing apparatus10further applies pressure to the magnets M whose circumferential positions have been determined by the blades12(Step S103).

Then, using the fastening member100, the rotor manufacturing apparatus10fastens the magnets M to which pressure is applied (Step S104).

The rotor manufacturing apparatus10then withdraws the blades12(Step S105). After withdrawing the blades12, the rotor manufacturing apparatus10allows the pushers11to drive (Step S106) and finishes processing.

As described above, the rotor manufacturing apparatus according to the embodiment includes pushers (pressing portions) and multiple blades (blade portions). The pushers press multiple temporarily attached magnets (permanent magnets) arranged side by side in the circumferential direction of the rotor core from the radially outer side of the rotor core. The multiple blades are individually inserted into gaps between the magnets pressed by the pushers.

Thus, the rotor manufacturing apparatus according to the embodiment is capable of appropriately positioning the permanent magnets even in a small rotor while keeping costs low.

In the above described embodiment, the case of manufacturing small rotors mainly for small motors is taken as an example. However, the size of a motor or rotor is not limited. Thus, the present disclosure is applicable to, for example, a middle or large motor having a configuration in which segment magnets are arranged side by side in the circumferential direction of the rotor core.

In the above-described embodiment, a case is described where the magnets are attached to the circumferential surface of the rotor core at two levels in the axial direction. The magnets may be attached at levels exceeding two. The magnets may be attached at one level, instead.

In the above-described embodiment, a fastening member formed into a belt is taken as an example, but this is not the only limitation. For example, the fastening member may be a member having a bracket shape through which the shaft penetrates and that covers the end portion of the rotor core.

The present disclosure is applicable to not only the case of attaching segment magnets to the circumferential surface of the rotor core but also the case of manufacturing products that require attachment of segment parts to a circumferential surface in the circumferential direction.

Those skilled in the art may easily conceive of further effects and modifications. Thus, broader aspects of the present disclosure are not limited by specific details and the exemplary embodiment illustrated and described thus far. Therefore, various changes are possible without departing from the spirit and the scope of the general concept of the present disclosure defined by the scope of the appended claims and their equivalents.