JPH04364342A - Super high speed electric rotating machine - Google Patents

Abstract

PURPOSE:To realize a super high speed electric rotating machine, e.g. a motor or a generator, by evacuating the air gap between a rotor and a stator forcibly thereby lowering the density of inner gas sufficiently. CONSTITUTION:At least one of the outer peripheral face of a rotor 2 or the inner peripheral face of a stator 4 is formed of a continuous irregular face 18 having hooked ridges or grooves 19, 19,... so that the air gap G is evacuated forcibly through the ridges or the grooves 19, 19,... when the rotor 2 rotates at super high speed.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to electric rotating machines such as motors and generators, and particularly to ultra-high speed electric rotating machines whose rotor rotation speed exceeds 100,000 rpm.

0002

2. Description of the Related Art Generally, losses occurring in this type of electric rotating machine include electrical loss, magnetic loss, loss due to friction, and the like. For example, when increasing the speed of a conventional motor to an ultra-high speed, among the above losses, friction loss becomes a particular problem. Friction loss can be divided into contact friction loss at bearings and seals, and wind loss due to high speed rotation of the rotor, that is, loss due to viscous shearing of the air present in the air gap. Regarding the former type of contact friction loss, the loss has been significantly reduced by making the bearing non-contact, such as by supporting the rotor shaft with a magnetic bearing (for example, Japanese Patent Application Laid-Open No. 1-1)
(Refer to Publication No. 45420 and Japanese Utility Model Application Publication No. 2-85012)
.

0003

[Problem to be Solved by the Invention] However, little consideration has been given to the latter windage loss, and a solution to this problem has been awaited. Incidentally, it is known that windage loss varies greatly depending on the type of gas used to cool the coil. For example, when hydrogen is used as a cooling medium, windage loss is lower than when air is used as a cooling medium. It can be reduced to about 85-90%.

[0004] The present invention was proposed in view of the above, and its purpose is to forcibly exhaust the gas existing in the air gap to the outside and sufficiently reduce the gas density inside the air gap. The goal is to reduce losses and achieve ultra-high speeds in electric rotating machines.

[0005]

[Means for Solving the Problems] In order to achieve this object, in the present invention, at least one of the outer circumferential surface of the rotor or the inner circumferential surface of the stator, which faces inside and outside, in an ultra-high-speed electric rotating machine is formed into a continuous uneven surface. The shape of the protrusions or grooves constituting the continuous uneven surface is bent into a substantially dogleg shape so that the middle part in the rotor axis direction is offset from both ends, and when the rotor rotates, the protrusions or grooves The concave groove allows the gas in the air gap to be discharged to the outside. The above-mentioned protrusions and grooves bent into a substantially doglegged shape are opposite in direction depending on whether they are provided on the rotor or on the stator. this is,
This is due to the difference in state between the rotating rotor and the non-rotating stator.

Specifically, in the invention of claim 1, as shown in FIGS. 1 and 2, the ultra high-speed electric rotating machine has a stator (4
), rotatably supported inside the stator (4),
Air gap (G) between the outer circumferential surface and the inner circumferential surface of the stator (4)
The outer peripheral surface of the rotor (2) has a large number of continuous protrusions or grooves (19), (19), etc. in the circumferential direction. The continuous uneven surface (18) is composed of a continuous uneven surface (18), and the continuous uneven surface (18)
8) Convex lines or concave grooves (19), (19),...
Each of these requires that the intermediate portion in the rotor axial direction be bent in a substantially dogleg shape so that the intermediate portion in the rotor axial direction is shifted forward in the rotor rotational direction with respect to both end portions.

According to the second aspect of the invention, contrary to the first aspect of the invention, the inner circumferential surface of the stator is formed into a continuous uneven surface. That is, in this invention, as shown in FIG. 4(a), the stator (4) is rotatably supported inside the stator (4), and the outer circumferential surface forms an air gap with the inner circumferential surface of the stator (4). For an ultra-high-speed electric rotating machine equipped with a rotor (2) facing each other via a rotor (G), the inner circumferential surface of the stator (4) has a large number of protrusions or grooves (19) in the circumferential direction, (19)
,..., and each of the protrusions or grooves (19), (19),... constituting the continuous uneven surface (18) extends in the rotor axial direction. It is required that the intermediate portion of the rotor be bent in a substantially dogleg shape so that the intermediate portion thereof is shifted rearward in the rotor rotational direction with respect to both end portions.

In the third aspect of the invention, both the outer circumferential surface of the rotor and the inner circumferential surface of the stator are formed of continuous uneven surfaces. That is, in this invention, in the invention of claim 1, the inner peripheral surface of the stator (4) has a large number of protrusions or grooves (1) in the circumferential direction.
9), (19), ... consisting of a continuous uneven surface (18), and the convex grooves or grooves (19), (19), ... constituting the continuous uneven surface (18). Each of them is required to be bent in a substantially dogleg shape so that the intermediate portion in the rotor axial direction is shifted rearward in the rotor rotational direction with respect to both end portions.

[0009] In the invention according to claim 4, the stator (4)
A shaping sleeve (17) equipped with a center hole (17a) having a circular cross section is mounted inside the shaping sleeve (17).
The inner circumferential surface of the center hole (17a) constitutes the inner circumferential surface of the stator (4).

0010

[Operation] In the invention of claim 1, since the outer circumferential surface of the rotor (2) is constituted by a continuous uneven surface (18), the rotor (2)
), the gas in the air gap (G) moves around the bent corners (
19a) and is forcibly pushed out toward the opening of the gap (G) at both ends (19b), (19b). The area between the bent corner (19a) and both ends (19b), (19b) of the protruding strip or groove (19) is inclined with respect to the direction parallel to the axis of the rotor (2), and in this inclined portion This is because an extrusion force directed outward in the axial direction acts on the gas. This exhaust effect increases as the rotor rotation speed increases, and in extremely high-speed rotation conditions, the air gap (G
), the apparent viscosity of the gas decreases, and the loss due to viscous shear of the gas can be reduced to an almost negligible level.

In the invention of claim 2, on the contrary, the stator (4
) has a continuous uneven surface (18), so the exhaust effect as in the invention of claim 1 cannot be obtained, but the gas in the air gap (G) is not dragged by the rotor (2). Since the rotor (2) rotates at an extremely high speed, the gas also flows at high speed in the same direction. This flowing gas has protrusions or grooves (19), (19)
, ... and is guided by the slope of the gap (G)
Pushed towards the opening. Therefore, in this case as well, the gas within the air gap (G) can be sufficiently diluted to reduce the gas density.

[0012] In the invention of claim 3, the above-mentioned claims 1 and 2
The effects of both inventions can be obtained synergistically, which is more advantageous.

[0013] In many cases, a groove for loading the coil is opened on the inner peripheral side of the stator (4). This groove significantly impedes the exhaust action of the continuous uneven surface (18) and is likely to be rendered ineffective. In order to avoid such problems, in the invention according to claim 4, a shaping sleeve (17) provided with a center hole (17a) having a circular cross section is installed inside the stator (4).

[0014]

Embodiments Hereinafter, embodiments of the present invention will be explained based on the drawings. 1 to 4 show an embodiment in which the present invention is applied to an ultra-high speed motor. In Figure 2, the motor has a housing (1
), a rotor (2), a rotor shaft (3) that supports the rotor (2), and a stator (4) into which the rotor (2) is fitted. The upper and lower ends are rotatably supported by magnetic bearings (5) and (6), respectively. The magnetic bearings (5) and (6) are
Consisting of a rotor (7) fixed to the rotor shaft (3) and a stator (8) fixed to the inner surface of the housing (1), the magnetic force of the magnet (9) embedded in the stator (8) are concentrated on opposing magnetic poles (10) and (11) that face each other on the thrust rotation surface of the rotor (7) and stator (8), and support the rotor shaft (3) in a non-contact state. There is.

The upper magnetic bearing (5) functions only as a radial bearing, but the lower magnetic bearing (6) also functions as a dynamic pressure type thrust bearing. For details, refer to the opposing magnetic pole (1
A non-magnetic ceramic ring (
12) and (13), and both rings (12) and (1
A spiral groove is provided on one of the facing surfaces of 3), and the rotor shaft (
3) rotates at an extremely high speed, the rotor (7) and the rotor shaft (3) can be supported in a floating manner by the pressure of the airflow generated in the grooves.

The stator (4) has a core (15) made of a laminate of steel plates as a magnetic material, and a coil (1
6), and has a central hole (17a) with a circular cross section inside.
) are fixed in a press-fitted state. Orthopedic sleeve (1
7) is made of non-magnetic material. This orthopedic sleeve (1
The inner peripheral surface of the center hole (17a) of 7) constitutes the inner peripheral surface of the stator (4), and an air gap (G) is provided between this inner peripheral surface and the outer peripheral surface of the rotor (2). There is.

[0017] In order to reduce windage loss when the rotor (2) rotates at an extremely high speed, the outer peripheral surface of the rotor (2) facing the air gap (G) is constituted by a continuous uneven surface (18). . As shown in FIG. 3, the continuous uneven surface (18) is composed of a group of grooves (19), (19), etc. formed continuously in the circumferential direction on the outer peripheral surface of the rotor (2). There is. As shown in FIG. 4(a), each groove (19) is connected to the rotor (2).
) is at both ends (19b), (19b)
The bent corner (19a), which is the central part, is on the front side in the rotational direction of the rotor (2) (the right side in Fig. 4(a)) than both ends (19b), (19b). ). In addition, the gap dimensions of the air gap (G), the width and depth of each groove (19), and also Fig. 4
Regarding the inclination angle of the groove (19) in the unfolded state,
Set according to the rotation speed of the rotor (2), etc.

Therefore, in this embodiment, the rotor (2
) rotates, the air present in the air gap (G) is dragged by the slope between the bent corner (19a) and both ends (19b), (19b) of each groove (19). . On the other hand, the air in the groove (19) is pressed against the side wall of the inclined part, and a gap (G) is formed at both ends (19b), (19b) with the bent part (19a) as a boundary.
is pushed towards the opening. When the pressure in the groove (19) decreases due to this extrusion action, the air in the air gap (G) subsequently flows into the groove (19), so the pressure in the air gap (G) also decreases. As the rotational speed of the rotor (2) increases, the exhaust action by the groove (19) becomes even greater, and in ultra-high speed rotation, the pressure in the air gap (G) reaches a level lower than atmospheric pressure. can descend and reduce the air density there sufficiently. Therefore, windage loss due to viscous shear of air can be reduced to a negligible extent, and the motor can be rotated at an extremely high speed.

Furthermore, since the shaping sleeve (17) is installed inside the stator (4), even if the groove for loading the coil (16) is opened on the inner circumferential side of the stator (4), the groove is Continuous uneven surface (18)
The exhaust action can be maintained effectively.

In the above embodiment, the continuous uneven surface (18) was provided on the outer peripheral surface of the rotor (2), but the continuous uneven surface (18)
) is the inner peripheral surface (
It can also be provided on the inner peripheral surface of the stator (4). When providing a continuous uneven surface (18) on the stator (4) side, as shown in FIG.
A concave groove (1) provided on the outer circumferential surface of the rotor (2)
The bent corner (19a) is opposite to the bending direction of 9).
is bent so that it is deviated from both ends (19b), (19b) to the rear side in the rotational direction. By doing this, the rotor (
2) rotates at an extremely high speed, the gas in the air gap (G) is dragged by the rotor (2) and flows at high speed in the same direction as the rotor (2), causing convex lines or concave grooves on the continuous uneven surface (18). When the gas collides with each of (19), (19), . . . , it is guided by the slope of the protruding strip or groove (19) and is pushed out toward the gap (G) opening side. Therefore, the gas in the air gap (G) can be sufficiently diluted to reduce the gas density.

Furthermore, the continuous uneven surface (18) is attached to the rotor (
2) and the center hole (17a) of the orthopedic sleeve (17).
) and the inner circumferential surface (the inner circumferential surface of the stator (4)). In this case, the exhaust effect from the air gap (G) increases synergistically and the rotor (
2) can be rotated.

In addition to the concave grooves (19), (19), . . . as in the above embodiments, the continuous uneven surface (18) has a large number of curved protrusions continuously fixed in the circumferential direction on the circumferential surface. It can also be formed with. Further, in the unfolded state, the grooves and the protrusions do not necessarily have to be linear in portions other than the bent corners (19a), and the entirety may be bent in an arc shape.

Furthermore, the present invention can be widely applied to other electric rotating machines such as generators, in addition to the motors of the above embodiments.

[0024]

As explained above, according to the invention of claim 1, 2 or 3, at least one of the outer circumferential surface of the rotor and the inner circumferential surface of the stator is formed with a continuous uneven surface. The formed protrusions or grooves are bent into a substantially dogleg shape so that when the rotor rotates at ultra-high speed, the gas in the air gap is forcibly exhausted by the protrusions or grooves. , it is possible to sufficiently reduce the gas density in the air gap during ultra-high-speed rotation and lower the apparent gas viscosity, which reduces the loss due to viscous shear of the gas to an almost negligible level, making it possible to It is possible to achieve ultra-high speed rotating machines.

According to the fourth aspect of the invention, the shaping sleeve having the center hole having a circular cross section is mounted inside the stator, and the inner peripheral surface of the center hole is used as the inner peripheral surface of the stator. Even if a coil loading groove is opened on the circumferential side, the influence of the groove can be suppressed, and the exhaust effect due to the continuous uneven surface can be effectively maintained.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing essential parts of an ultrahigh-speed motor according to an embodiment of the present invention.

FIG. 2 is a longitudinal cross-sectional view showing a schematic structure of an ultra-high-speed motor.

FIG. 3 is a sectional view of a main part showing an air gap and a structure around the air gap.

FIG. 4 is an explanatory diagram showing a developed shape of a continuous uneven surface.

[Explanation of symbols]

(2)...Rotor (4)...Stator (17)…Orthopedic sleeve (17a)...center hole (18)...Continuous uneven surface (19)...concave groove (G)...Air gap

Claims (4)

[Claims] Claim 1: A stator (4) and the stator (4).
is rotatably supported inside the stator (4), and the outer peripheral surface is the stator (4).
An ultra-high-speed electric rotating machine comprising a rotor (2) disposed opposite to each other on the inner circumferential surface of the rotor (2) through an air gap (G), the outer circumferential surface of the rotor (2) having a large number of protrusions or stripes in the circumferential direction. Concave groove (1
It is composed of a continuous uneven surface (18) of 9), (19), ..., and each of the protrusions or grooves (19), (19), ... constituting the continuous uneven surface (18) is An ultra-high-speed electric rotating machine in which the middle part of the rotor in the axial direction is bent in a substantially dogleg shape so that it is shifted forward in the rotor rotational direction with respect to both ends. Claim 2: A stator (4) and the stator (4).
is rotatably supported inside the stator (4), and the outer peripheral surface is the stator (4).
An ultra-high-speed electric rotating machine comprising a rotor (2) disposed opposite to each other on the inner circumferential surface of the stator (4) through an air gap (G), the inner circumferential surface of the stator (4) having a large number of protrusions in the circumferential direction. or concave groove (
It is composed of a continuous uneven surface (18) of 19), (19), ..., and each of the protrusions or grooves (19), (19), ... constituting the continuous uneven surface (18) is An ultra-high-speed electric rotating machine in which the middle part of the rotor in the axial direction is bent in a substantially dogleg shape so that it is shifted rearward in the rotor rotational direction with respect to both ends. Claim 3: The inner circumferential surface of the stator (4) is composed of a continuous uneven surface (18) having a large number of protrusions or grooves (19), (19), ... in the circumferential direction, and has continuous unevenness. Face (18
), each of the convex grooves or concave grooves (19), (19), ... is bent into a substantially doglegged shape such that the middle part in the rotor axis direction is shifted rearward in the rotor rotational direction with respect to both ends. The ultra high-speed electric rotating machine according to claim 1. 4. A shaping sleeve (17) having a center hole (17a) with a circular cross section is installed inside the stator (4).
7a) The ultra-high-speed electric rotating machine according to claim 1, 2 or 3, wherein the inner circumferential surface of the stator (4) is constituted by the inner circumferential surface of the stator (4).