JPS63202249A - Rotor for motor - Google Patents

Abstract

PURPOSE:To reduce the weight of a rotor, by a method wherein a cylindrical section is formed around a sleeve, fitted and fixed to a rotary shaft, while a cylindrical yoke is arranged. CONSTITUTION:A sleeve 1 is fitted and fixed to a rotary shaft of a motor. A cylindrical hollow section is formed around the sleeve 1 and a cylindrical yoke 2 is arranged around the cylindrical section. Both ends of the sleeve 1 and the yoke 2 are held and fixed by flanges 4, 4a. A ferrite magnet 3 is arranged around the yoke 2 and a reinforcing tube member 6 is arranged around the ferrite magnet 3.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention particularly relates to a permanent magnet rotor for an electric motor, which has an improved structure for reducing weight.

[Conventional technology]

Conventionally, as a rotor structure of a permanent magnet type electric motor,
No. 9-097588 has been proposed. According to this proposal, a yoke made of laminated steel plates formed between the outer periphery of the rotating shaft and the inner periphery of a cylindrical permanent magnet, a permanent magnet, and a surface reinforcing material are combined by aluminum die-casting. This structure has the advantage that even if there is some dimensional variation in the permanent magnets, it can be absorbed by the aluminum die-casting, and that the balance weight part can be simultaneously molded into the die-cast shape. However, this rotor has the problem that the greater the weight, the worse the speed response of the rotor (effect of inertia), and the friction wear of the bearing increases as the rotational speed of the shaft increases. There is also the problem of increasing numbers. Wear friction in bearings occurs due to the synergistic effect of load and sliding speed (generally referred to as Pv value), so in bearings operated at high speeds, unless the load is reduced, abnormal wear or seizure may occur. Since the weight of the zero rotor also becomes part of the load during operation, the size of this weight is also an extremely important issue.

[Problem that the invention seeks to solve]

As mentioned above, in the conventional rotor structure, the space between the outer circumference of the rotating shaft and the inner circumference of the magnet part is formed into a solid shape by a yoke made of laminated steel plates, and this portion accounts for a large weight ratio, increasing the weight of the rotor. This has the problem of reducing speed response and causing friction and wear on the bearing part, and no consideration was given to reducing weight by providing cylindrical hollow parts on the inner periphery of the magnet part and the outer periphery of the rotating shaft. .

The present invention was made in view of the above situation, and an object of the present invention is to provide a rotor for an electric motor whose weight can be significantly reduced.

[Means for solving problems]

The above purpose is to provide a sleeve that is fitted and attached to a rotating shaft of an electric motor, a cylindrical yoke that is disposed with a cylindrical hollow part formed on the outer periphery of the sleeve, and a cylindrical yoke that is formed in a cylindrical shape and that is fitted on the outer periphery of the yoke. This is achieved by a rotor for an electric motor that is provided with a permanent magnet and a reinforcing member tube that is fitted and fixed to the outer periphery of the magnet.

[Effect]

As will be described later in the description of the embodiment, a cylindrical hollow part 8 is formed on the outer periphery of the sleeve 1 which is fitted and fixed to the rotating shaft, and a cylindrical yoke 2 is disposed therein. Both ends of yoke 1 and yoke 2 are held and fixed by flanges 4.4a. Therefore, the weight of the rotor corresponding to the volume of the hollow portion 8 is reduced.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS The rotor for an electric motor according to the present invention will be explained below using embodiments with reference to FIGS. 1 to 6. 1 is a longitudinal sectional view, FIG. 2 is a sectional view taken along the line A-A in FIG. 1, FIGS. 3 to 5 are perspective views of the sleeve, flange, and cylindrical magnet in FIG. The figure is also a sectional view of the clasp. In the figure, 1 is a sleeve made of a steel layer, 2 is a cylindrical yoke made of magnetic material, 3 is a cylindrical ferrite magnet, 4.4a is a metal flange, 5.5a is a soft metal clasp, and 6 is a cylindrical yoke made of magnetic material. This is a reinforcing member tube made of non-magnetic material. The sleeve 1 has a coupling part 7 on the axial center side through which a rotating shaft (not shown) is inserted and fixed, and the rotating shaft is coupled to the coupling part 7 by press-fitting or the like.

A cylindrical hollow part 8 is formed between the outer periphery of the sleeve 1 and the inner periphery of the yoke 2 with a flange 4.4a interposed therebetween.
A ferrite magnet 3 is placed on the outer circumference of the yoke 2.
A reinforcing member tube 6 is disposed around the outer periphery of the reinforcing member tube 6.

At both upper and lower ends of the sleeve 1, an annular groove 9.9a is provided on the outer periphery as shown in FIG.
As shown in FIG. 4, a stepped portion 10 is provided on the inner peripheral portion of the holder. Then, the yoke 2 and the ferrite magnet 3 are inserted into the outer circumference of the sleeve 1, and the clasps 5.5a are inserted into the upper and lower parts of the magnet 3, and then the yoke 2. The flange 4.4a is inserted from above and below to sandwich the magnet 3 and the clasp 5.5a. Then, a push blade (not shown) is inserted into the gap 11, lla created between the outer periphery of the upper and lower ends of the sleeve 1 and the stepped portion 1o of the inner periphery of the flange 4.4a.
By being pressurized from above and below in the direction of the arrow in the figure, a part of the flesh of the flange 4.4a is plastically deformed and flows into the annular groove 9.9a, and the sleeve 1 and the flange 4.4a are firmly crimped and connected. .

Thereafter, the reinforcing member tube 6 is fitted around the outer periphery of the magnet 3, and the rotor as shown in FIG. 1 is completed.

In the above-described connection between the sleeve 1 and the flange 4.4a, good connection can be obtained by, in principle, making the material of the flange 4.4a softer than the material of the sleeve 1. When the sleeve 1 is made of steel as in this embodiment, a good bond can be obtained regardless of whether the flanges 4, 4a are made of aluminum and aluminum alloys, zinc and zinc alloys, copper and copper alloys. . Also, sleeve 1
When hard steel is used for the flange 4.4a, a good bond can be obtained even if mild steel is used for the flange 4.4a material. and an annular groove 9.
Any shape can be used for 9a as long as it produces a wedge effect and compressive residual stress of the inflowing metal, and although a screw-shaped groove is used in this example, a square groove, a circular groove, etc. can also be crimped in the same way. Effects can be obtained. The number of grooves may be selected from a single groove, multiple grooves, etc. depending on the required strength of crimping.

Note that the hole 12 (see FIG. 3) provided in the body of the sleeve 1 is a hole for venting gas, and if the rotor of this embodiment is fixed by firing, it should be noted that the hole 12 (see FIG. 3) is a hole for venting gas. The high pressure of water vapor generated when water droplets remain is released into the atmosphere, and the sleeve 1, yoke 2 is deformed, or the flange 4
．． The omission of 4a is to prevent such problems. Therefore,
If the rotating shaft is fixed by press-fitting, the hole 12 is not necessary.

The cylindrical permanent magnet 3 is provided with cutouts 13.13a in the radial direction as shown in FIG. A notch 14 is provided in the clasp 5.5a, and a sixth
Protrusions 15a, 15 in the vertical direction (thickness direction) as shown in the figure.
b is provided. When the magnet 3 is axially clamped between the flange 4.4a and the clasp 5.5a, the protrusion 15a of the clasp 5, 5a engages with the notch 14 of the flange 4.4a, and the protrusion The portion 15b is the cutout portion 1 of the magnet 3
3.13a to prevent the magnet 3 from rotating during rotation. In the example of Figure 6, the clasp 5.5a
Although the protrusions 15a and 15b are arranged at angular positions shifted by 90 degrees, they can be arranged at any position including symmetrical positions in the thickness direction. Further, the material of the clasps 5, 5a is preferably softer than the material of the flange 4.4a and the magnet 3 due to their purpose of use, and is preferably non-magnetic in order to prevent magnetic leakage. Soft aluminum alloy was used.

A cylindrical portion 16.16a (see FIG. 1) provided on the flange 4.4a acts as a positioning guide for forming a hollow portion 8 at a constant distance between the sleeve 1 and the yoke 2 during assembly. Further, the axial length of the yoke 2 is such that when a pressing force is applied to the flanges 4, 4a for caulking the joint, the flange 4.4a and the magnet 3 are connected by this pressing force.
After the clasp 5.5a, which is sandwiched between the It is desirable to set the length to a length that does not cause damage to the ferrite magnet 3, thereby preventing damage to the ferrite magnet 3.

As shown in FIG. 1, the flange 4.4a can be integrally provided with a balance weight portion 20.20a, thereby reducing the number of parts and improving ease of assembly. Any method such as machining, casting, die-casting, etc. can be used to process the flange 4.4a, but if the balance weight part 20.20a is provided in one piece, there will be multiple shapes, so a die-casting method may be used. It is economical to do so. The purpose of the reinforcing member tube 6 is to prevent fragments from scattering in the event that the ferrite magnet 3 is damaged, and a thin walled tube made of a non-magnetic material is used. The purpose of using non-magnetic material is to prevent magnetic leakage, and in this embodiment, a thin stainless steel tube is press-fitted and fixed.

As described above, in the electric motor rotor of this embodiment, since the cylindrical hollow part is formed between the sleeve and the yoke, the weight of the rotor can be reduced by the volume of this hollow part. Therefore, the speed response of the rotor is improved and wear of the bearing portion can be reduced.

7 to 9 show other embodiments, FIG. 7 is an oblique view of the divided magnet, FIG. 8 is an explanatory diagram of a connecting part where the magnets shown in FIG. 7 are combined, and FIG. This embodiment is a cross-sectional view of a rotor using magnets, and the differences from the above embodiment are as follows.
In the above embodiment, the magnet 3 is integrally cylindrical, whereas in this embodiment, the magnet 3 is formed into a cylindrical shape using four divided magnets 17. The divided magnet 17 has chamfered portions 18 at the four corners, and when assembled, the protrusion of the clasp 5.5a is inserted into the V-shaped groove 19 formed between the chamfered portions 18 and 18 at the seams of the divided magnet 17, as shown in FIG. The split magnet 17 is prevented from rotating by engaging the protrusion 15a with the notch 14 of the flange 4.4a, and is assembled in the same manner as the cylindrical magnet. This example also has the same effects as the above example.

〔Effect of the invention〕

As described above, the electric motor rotor of the present invention has the effect of reducing the weight of the rotor.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view of an embodiment of a rotor for an electric motor according to the present invention;
2 is a sectional view taken along the line A-A in FIG. 1, FIG. 3 is a perspective view of the sleeve in FIG. 1, and FIG. 4 is a perspective view of the flange.
FIG. 5 is a perspective view of the cylindrical magnet, FIG. 6 is a sectional view of the clasp, FIG. 7 is a perspective view of a divided magnet of another embodiment of the motor rotor of the present invention, and FIG. FIG. 7 is an explanatory view of a coupling portion in which the magnets shown in FIG. 7 are coupled, and FIG. 9 is a cross-sectional view of a rotor using the magnets shown in FIG. 1...Sleeve, 2...Yoke, 3...Magnet, 6
. . . Reinforcing member tube, 8 . . Hollow portion, 17 . . . Division magnet. 1 mouth $3 cause 6, fine coffin, wood pipe δ, hollow part 'Jl: 5 figure stem 8 figure ¥, 6th f5α V, 7 no ¥, 9 mouth I7- meeting; squirrel-klcI

Claims (1)

[Claims] 1. A sleeve fitted and fixed to the rotating shaft of the electric motor, a cylindrical yoke formed in a cylindrical hollow part on the outer periphery of the sleeve, and a cylindrical yoke formed in a cylindrical shape and fitted on the outer periphery of the yoke. 1. A rotor for an electric motor, comprising a permanent magnet and a reinforcing member tube fitted and fixed to the outer periphery of the magnet.