JPH07107705A - Cooling mechanism for outer rotor type high-speed electric rotating machine - Google Patents

Abstract

PURPOSE:To minimize a plurality of and a pluraliry of kinds of slots, and to reduce cost by forming these slots along the central axis of a fixed shaft for supplying and discharging cooling water and considerably requiring the mandays of the machining of the slots in the, cooling mechanism of a conventional outer rotor type electric rotating machine. CONSTITUTION:A slot 28 having a comparatively large diameter is formed along the central axis of a fixed shaft 21, a copper pipe 29 is inserted, and the inside of the copper pipe is used as water supply and the outside as drainage.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an outer rotor type high speed rotating electric machine, and more particularly to an improved cooling mechanism for an outer rotor type high speed rotating spindle motor.

[0002]

2. Description of the Related Art FIG. 3 shows a partially cut front view of a spindle motor as an outer rotor type high speed rotating electric machine which has been recently developed, and FIG. 4 shows a side view of the section AA of FIG. . The outline of the structure will be described with reference to these drawings.
There is an iron core 2 fixed to the outer circumference on the free end side (almost in the middle of the left and right in the axial direction in the figure) and a stator 4 having a coil 3 inserted in the groove of this iron core. The shaft end portion (left end in the figure) of the rotor 6 having the secondary electric machine member 5 surrounding the outer periphery forms a spindle 6 '. This rotor 6
Is a support flange 10 which is housed in a casing 9 having an end flange 7 on the spindle side and a bearing flange 8 on the opposite side, and which supports and fixes the fixed shaft 1 adjacent to the bearing flange 8, and further on the right end in the figure. Is provided with a flange 11. Since this rotor 6 rotates at a high speed such as 100,000 rpm, an air bearing is used and three arc-shaped pads 12, 13 and 14 are supported so as to be swingable in the radial direction. The high-pressure air from the three rightmost air inlets 11a to 11c passes through the passage P and is ejected in the radial direction from the ejection ports 12a, 12b, 13a, 13b, 14a, 14b, and in the thrust direction. Exits 7a-7c, 8a-8
Eject from c.

On the other hand, the cooling mechanism of this outer rotor type high speed rotating electric machine will be described. A spiral groove 17 is formed in a portion of the outer peripheral surface 16 of the fixed shaft 1 substantially corresponding to the iron core 2, and the outer peripheral surface of the fixed shaft is formed. A flow path of cooling water is formed between the fitted sleeve 23 and the sleeve 23. The cooling water supplied to the inlet 11d has a horizontal hole 1a, a vertical hole 18, grooves 17a, 1
7, 17b, 19, notch 20, groove 21, and oblique hole 22 to return to the long hole 1'b, and is circulated to the heat exchanger and pump (not shown) through the cavity 10a and the outlet 11e.

[0004]

With the above cooling mechanism, a spiral flow path having an extremely good cooling effect can be obtained, but long holes 1a, 1'are formed in a relatively elongated fixed shaft for water supply and drainage therein. b) Further, since machining such as notches and oblique holes is required, simplification of these has been demanded.

[0005]

According to the present invention, one long hole coaxial with the central axis of the fixed shaft is bored from the fixed end portion of the fixed shaft, and a metal pipe (such as a non-metal pipe) made of copper or the like is formed in this long hole. (Applicable) is inserted so that the tip of the pipe communicates with one end of the spiral flow path and the other end of the spiral flow path communicates with the outside of the copper pipe.

[0006]

Operation: The cooling water supplied to the copper pipe at the fixed end of the fixed shaft passes through the inside of the copper pipe, enters the spiral flow path at the tip of the copper pipe, and returns while cooling the iron core through the sleeve. At the end of the flow path, it passes between the outside of the copper pipe and the elongated hole, further flows through the hole at the fixed end to the outlet, and is circulated to the heat exchanger and the pipe. The gap between the outside of the copper pipe and the slot is filled with the return water from the end of the spiral flow path over the entire length, so that the central axis portion of the fixed shaft is also sufficiently cooled.

[0007]

1 is a sectional side view of an embodiment of an outer rotor type rotating electric machine having a cooling mechanism according to the present invention, and FIG. The structure of this outer rotor type rotating electric machine will be described. A spiral groove 23 is provided on the outer periphery 22 of a portion of the fixed shaft 21 close to the fixed end portion from the free end portion side. A sleeve 24 is covered, an iron core is externally fitted to the outer periphery of the sleeve 24, and a coil 26 is arranged in a groove of the iron core in the axial direction to form a stator 27. Further, an elongated hole 28 is bored from the fixed end portion 21a coaxially with the central axis of the fixed shaft 21, and a copper pipe 29 having an outer diameter smaller than the inner diameter of the elongated hole is inserted into the elongated hole 28. The part 29a is abutted against the conical bottom 28a of the slot 28, which communicates with the spiral groove 23 by means of a radial hole 30. Although a copper pipe is used in this embodiment, other metal pipes may be used. The end of the spiral groove 23 on the fixed end 21a side communicates with a gap 32 between the outer circumference of the copper pipe 29 and the inner circumference of the elongated hole 28 by a hole 31 in the radial direction.

The above is the cooling mechanism. To explain still another part, the rotor 35 has a secondary side electric member 34 surrounding the stator 27 fixed to the inner periphery thereof and one end ( Figure 1
The flange 36 is bolted to the left)
A spindle 36a is integrally formed on the outer side of the axial end of the central portion of 6. The rotor 35 is supported by a pair of radial air bearings 38, 38 held by a casing 37 in front of both ends in the axial direction thereof, and the thrust air bearing flange 39 and the thrust air are axially supported. It is supported via a flange 36 that is sandwiched between bearings 40. The thrust air bearing flange 39 is a casing.
A thrust air bearing 40 is attached to the outer end of the casing 37, outside the radial air bearing 38 (left in FIG. 1), and on the inner periphery of the casing 37 in front of the thrust air bearing flange 39. A fixing flange 41 for fixing the outer circumference of the fixed end portion 21a of the fixed shaft 21 having a large diameter is attached to the opposite side of the casing 37 from the thrust air bearing flange 39. Is engaged with the outer circumference of the fixed end portion 21b having a smaller diameter of the fixed shaft 21, a cooling water inlet 43 is provided at this fixed end portion 21b, and a cooling water outlet 44 and compressed air are provided at the fixed flange 41. An inlet 45 is provided and the cooling water outlet 44 is provided at the fixed end 21.
It communicates with the elongated hole 28 through an L-shaped hole 46 formed in a. On the other hand, the compressed air inlet 45 opened near the upper right end of the casing 37 is provided with jet ports 38a to 38d of the radial air bearings 38 and 38 and jet ports 39a and 39b of the thrust air bearing flange 39 through the respective passages. , Thrust air bearing flange 39 and jet ports 39a and 39b, and thrust air bearing 40 jet ports 40a and 40b.

Next, the operation of the cooling mechanism of the outer rotor type rotary electric machine will be described. The cooling water supplied from the cooling water inlet 43 to the copper pipe 29 via the joint 47 is supplied from the tip portion 29a of the copper pipe to the hole 30, the spiral groove 23, and the hole 3.
1, through the gap 32 and the hole 46, flows to the cooling water outlet 44, and is circulated by a heat exchanger and a pump (not shown). Hole 31
Since the gap 32 is filled with the cooling water over the entire length by the return water flowing from the gap 32 to the gap 32, the central portion of the fixed shaft 21 is cooled through the copper pipe and the water in the gap 32, and the spiral groove 2
The cooling water flowing through 3 makes it more effective to cool the iron core.

[0010]

The elongated hole in the fixed shaft is only one hole having a slightly larger diameter, and the insertion of the copper pipe is extremely easy, and the number of processing steps is remarkably reduced as compared with the conventional method. Further, the diameter of the fixed shaft can be reduced, the number of parts is small, and a compact outer rotor type electric rotating machine can be obtained as a whole, and the manufacturing cost can be reduced.

[Brief description of drawings]

FIG. 1 is a side sectional view showing an embodiment of an outer rotor type rotating electric machine having a cooling mechanism according to the present invention.

FIG. 2 is a front view taken along the arrow B of FIG.

FIG. 3 is a front view of a conventional outer-rotor electric rotating machine.

FIG. 4 is a cross-sectional side view taken along the line AA of FIG.

[Explanation of symbols]

 21 fixed shaft 21a, 21b fixed end 22 outer circumference 23 spiral groove 24 sleeve 26 coil 27 stator 28 long hole 29 copper pipe 29a tip part 32 gap 34 secondary side electric member 35 rotor 36 flange 36a spindle 37 Casing 38 Radial air bearing 39 Thrust air bearing flange 40 Thrust air bearing 41 Fixed flange

Claims (1)

[Claims] 1. A stator having a fixed shaft, an iron core fixed to the outer circumference of the fixed shaft on the free end side, a plurality of coils inserted in a groove of the iron core, and a stator having the stator. A rotor having a secondary electric machine member surrounding the outer periphery and fixing a flange integral with the spindle at one end, and a casing for holding two radial air bearings supporting the rotor at both ends. , A thrust air bearing flange and a thrust air bearing attached to one end of this casing, a fixed flange of a fixed shaft attached to the other end, and a fixed axis of the fixed shaft from the fixed end of the fixed shaft. Between a plurality of elongated holes formed in parallel, a spiral groove formed on the outer peripheral surface of the portion of the fixed shaft corresponding to the iron core, and between the outer circumference of the mountain portion of the spiral groove and the inner circumference of the iron core A spiral passage for cooling water is formed by the sleeve inserted in In the outer-rotor type high-speed rotating electric machine, the elongated hole is formed as one elongated hole coaxial with the central axis from the fixed end of the fixed shaft, and a metal pipe such as copper or A metal pipe is inserted, the tip of this pipe communicates with one end of the spiral flow passage, and the other end of the spiral flow passage communicates with the gap between the pipe and the slot. A cooling mechanism for an outer-rotor high-speed rotating electric machine characterized by: