JPS60102850A - Rotor structure of rotary electric machine - Google Patents

Abstract

PURPOSE:To prevent a magnet material from jumping or damaging at superhigh speed rotation time by closely winding carbon fiber on the outer periphery of the material of a rotor. CONSTITUTION:Flanges 3a, 3b are press-fitted to both ends of a magnet material 2 made, for example, of rare earth cobalt magnet material having excellent magnetic property so as to take the weight balance of a rotor and to treat the terminal of a reinforcing system. Since the material 2 has relatively small tensile strength such as 10-20kg/mm.<2>, reinforcing yarns 4 such as carbon fiber is closely wound on the periphery. The carbon fiber has extremely high tensile strength such as 250-450kg/mm.<2>, and the damage or deformation of the material can be prevented at the superhigh speed rotation time by winding the yarns by applying tension in advance in case of closely winding the fiber.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rotor structure of a rotating machine such as an electric motor or a generator capable of rotating at ultra-high speed.

In rotating machines such as motors and generators that use changes in magnetic flux to generate shaft output or induce voltage, the number of rotations will be large if other conditions such as the number of windings and number of magnetic poles are the same. Indeed, it is generally known that the shaft output and induced voltage increase.

However, as the rotational speed of the rotating machine increases, the centrifugal force increases and the stress acting on the rotor increases, potentially damaging the components of the rotor. A theoretical analysis and calculation of this point yields the following.

The mass of the rotor is m (g) and the radius is r (cm).

When the circumferential velocity is v (cm/sec), the centrifugal force F is expressed by the following formula.

Here, if the rotation speed of the rotor is n per second, v = 2π'
=fn... (2) (1) and (2). Therefore, the ratio R of this acceleration to the gravitational acceleration
Then, if we calculate the ratio R of centrifugal force to gravitational acceleration for several rotational speeds n as r-r2cm, we get: N (rpm) R 150050,4 5000559,5 1000022,38X102 20000 89 0.52 It is being considered to put this into practical use by keeping the acceleration relative to gravity as low as possible (for example, in polishing motors used by dentists).

On the other hand, in ultra-high-speed rotating machines, it is technically difficult to excite rotor magnetic poles using slip rings, so a structure using field poles using permanent magnets is adopted. However, conventional magnetic materials with excellent magnetic properties (such as rare earth Kolt magnets) do not have a very high tensile strength, at most 10 to 20 kg/m. For this purpose, for example, if a rotor is constructed by wrapping such magnetic material (with a specific gravity of about 8) around a steel rotating shaft with a diameter of 2 cm in a cylindrical shape with a thickness of 1 crh, the acceleration due to gravity during ultra-high speed rotation will be The limit is about 80, and the rotation speed is about 19001m. In reality, this number is likely to become much smaller if further derating is considered.

Therefore, in order to rotate at ultra-high speeds, the rotor must be made of a magnetic material with high tensile strength, at the cost of sacrificing some of its magnetic properties, or a metal pipe can be placed around the rotor to create a rotor made of magnetic material. Measures are being taken to prevent it from popping out.

However, a decrease in the magnetic properties leads to a decrease in the output of the rotating machine, and even with this method there is a limit to the rotation speed.

The present invention was made in consideration of the above points, and since magnet materials such as rare earth cobalt magnets have a large coercive force and a high residual magnetic flux density, when used in a rotor, the rotor and stator are A large gap can be provided between the two, and even if the gap is made this large, the output will hardly decrease. The present invention focuses on this point and the remarkable tensile strength of carbon fiber, which has recently been attracting attention as a new material.The present invention has focused on the remarkable tensile strength of carbon fiber, which has recently been attracting attention as a new material. This prevents materials from flying out or breaking, and enables ultra-high speed rotation.

The present invention will be explained below based on the drawings.

FIG. 1 is a perspective view of an embodiment of the rotor of a rotating machine according to the present invention, where l is a steel rotating shaft, and 2 is a magnetic material with excellent magnetic properties that is press-fitted and fixed around the rotating shaft l. Rare earth cobalt magnets such as , sintered or resin bonded samarium cobalt, 4 magnets are preferred. Flanges 3a and 3b are press-fitted into both ends of this magnet material in order to balance the weight of the rotor and to process the ends of the reinforcing system, which will be described later.

Magnet material 2 has a tensile strength of lO~20kg/rrm"-
Since it is relatively small, a reinforcing thread 4 such as carbon fiber is tightly wound around it. The next pair of fibers has a tensile strength of 250~. 4
It is extremely large at 50 kg/ff1m2, and by applying tension in advance when tightly wound, it is possible to adjust and prevent damage and deformation of the magnet material during ultra-high speed rotation. When the carbon fibers are closely wound and then impregnated with a matrix material and hardened to fix the fibers to each other and harden, the magnetic material is held even more firmly. The end of the reinforcing thread 4 is the magnetic material 2
It is processed by embedding it in the groove M of the flange fixed to both ends of the flange. In this case, the carbon fibers may be wound around the carbon fibers while adhering the maru- or lj-x material.

Here, a magnet material (specific gravity 8.5) of PJ cm is fixed to a steel rotating shaft with a diameter of 2 cm, and carbon fiber is placed around it.
．． Assuming that a rotor with a diameter of 4.4 cm is constructed by tightly winding the carbon fiber with a thickness of 2 cm, and that the carbon fiber wound three times in Table 1 m is considered to be a pressure vessel1, and that the tensile stress of the magnet material is O, then A =
Since the approximate expression 6375 x 10-4 R holds true, - based on this expression, the ratio of acceleration to gravity R and the stress A acting on the rotor surface for each rotation speed are estimated as follows.

N (rpm), RA (kg/1n2) IX104
z, 24xtoa 1.4285X104 55.9
X103 35.646X104 80.6 X103
51.387X104 109.7X103 69.
938X104 143.3X]0" 91.3510
X104 223.8Xl (15142,67]5X]
O'503.55XlO" 321.020X104
895.20X103 570.7 The tensile strength of commercially available carbon fiber is approximately 250 to 430 kg 1 mρ, so if this is used, approximately 15 X l 04 (
It is impressive that a rotor that can withstand ultra-high-speed rotation (rpm) or higher can be realized.

In this way, reinforcement to prevent damage to the magnet material can be achieved by simply wrapping a reinforcing thread such as carbon fiber, which has high tensile strength. The workability for reinforcing is extremely superior compared to the conventional method. In addition, the reinforcing yarn has a thick tensile strength (・
Since fibers are used, the stability of the magnet material during high-speed rotation can be strengthened by applying tension in advance during winding.

Instead of the reinforcing yarn used in the present invention, a thin plain cloth knitted from fibers with high tensile strength may be used.

As explained above, in the present invention, a magnet material with excellent magnetic properties is fixed to the rotating shaft, and reinforcing thread or reinforcing cloth with high tensile strength is tightly wound around the outer periphery of the magnet material. It is also possible to prevent the magnet material from breaking or flying out, and it is possible to realize a rotating machine with a rotor that can withstand ultra-high speed rotation.

When the rotor structure according to the invention is applied to a rotary machine that rotates at a low speed, the frequency is relatively low in the low-speed machine, so loss is reduced, and as a result, the magnetic flux density can be increased. That is, since the gap between the rotor and stator of the rotating machine can be narrowed, the reinforcing thread can be wrapped thinner, and the output per unit weight of the rotating machine can be increased. This means that the rotating machine itself can be downsized while obtaining the same output, and the present invention can provide excellent effects not only on ultra-high-speed rotating machines but also on low-speed rotating machines.

The present invention can be applied not only to the rotor of a rotating machine but also to cases where magnetic pole pieces are fixed to the outer periphery of a flywheel having a large diameter.

[Brief explanation of the drawing]

FIG. 1 is a partially sectional perspective view of a rotor of a rotating machine according to the present invention. 1...Rotating shaft 2...Magnetic material 3 a + 3 b...Flange 4...Reinforcement thread Patent applicant Yukigaya Control Laboratory Co., Ltd. Figure 1b Child thread Dakineyama jJ -E 1. ', x: 111 (March 23, Commissioner of the Japan Patent Office Kazu Inu Wakasugi 1, 4Il;'l Indication of application 1982 Patent Application No. 209094 2, Name of invention Rotor of rotating machine Structure 3, Relationship with Person Making the Amendment 1 11 yen of the detailed description of the invention of the applicant for special stay The specification of the present application is amended as follows: (1) Page 5, line 5 to page 5 Correct "carbon fiber" in the 6th line to "carbon fiber, ultra-high strength polyethylene #I! fiber, aromatic polyamide #lia, etc.", and "carbon fiber" in the 7th row to "carbon fiber"
Corrected with "high tensile strength fiber". (2) Between the 3rd and 4th lines on page 8 [In the above embodiment, carbon fiber is wound around the rotating shaft of the rotor and the magnet material, but the present invention is not limited to this. Alternatively, the carbon fiber may be wound into a cylindrical shape in advance, and the rotating shaft and the magnet material may be inserted and fixed together into the cylindrical body. Furthermore, although carbon m-fibers were used in this embodiment, high-tensile strength fibers such as ultra-high strength polyethylene fibers and aromatic polyamide fibers may be used instead. ” to join.

Claims (3)

[Claims] (1) A magnet material with excellent magnetic properties is fixed to the rotating shaft,
A rotor structure for a rotating machine, characterized in that a reinforcing member with high tensile strength is wrapped around the outer periphery of the magnetic material. (2) The rotor structure according to claim 1, wherein the magnet material is a rare earth cobalt magnet material. (3) The rotor structure according to claim 1 or @2, wherein the reinforcing member is carbon fiber.