JPH0580172U - Outer rotor type high-speed rotating electric machine - Google Patents

Abstract

(57) [Summary] [Object] To provide an outer rotor type high-speed rotating electric machine capable of preventing the fixed shaft from bending without increasing the diameter of the fixed shaft, the rotor, and thus the device. [Structure] The gap between the stator 4 and the rotor 6 is made smaller on the side of the support flange 10 and gradually widens from there to the side of the opposite support flange 10.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an outer rotor type high-speed rotating electric machine such as a machine tool spindle motor driven at a high speed such as tens of thousands of rpm, and in particular, the gap between the stator and the rotor on the supporting flange side is It relates to a product that is made smaller and gradually becomes larger toward the side opposite the support flange.

[0002]

[Prior Art]

 The conventional outer rotor type spindle motor is configured as shown in FIGS. FIG. 2 is a partially cut side view of a conventional outer rotor type spindle, and FIG. 3 is a vertical sectional front view taken along the line III-III of the same figure. In each of these figures, a stator 4 having an iron core 2 fixed to the outer periphery and a stator coil 3 inserted in a groove of the iron core 2 is mounted on the free end 1a side of the fixed shaft 1. A rotor 6 having permanent magnets 5 for the number of magnetic poles is arranged so as to surround the outer circumference of the stator 4. It should be noted that one end (the left end in the figure) of the rotor 6 extends beyond the end of the stator coil 3, and the spindle 6 whose axis is coaxial with the axis of the stator 4 and serves as a rotation axis. 'Is formed.

A tool (not shown) such as a grindstone is attached to the spindle 6 ′. The stator 4, the rotor 6 and the fixed shaft 1 are housed in a casing 9 having an end flange 7 on the spindle side and a bearing flange 8 on the opposite side. On the right side of the bearing flange 8 in the figure, a support flange 10 for supporting and fixing the fixed shaft 1 is arranged adjacently, and an end flange 11 is provided on the axially outer side. The fixed end of the fixed shaft 1 penetrates the rotating cylindrical portion 6a and is supported by the support flange 10.

Since the rotor 6 is rotated at a high speed, a tilting partial arc static pressure gas bearing (air bearing) is used in place of a roller bearing or the like, and as shown in FIGS. In the annular space between the casing 9 and the casing 9, three arcuate pads 12, 13, 14 which are divided in the circumferential direction and extend in the axial direction are arranged. Each of these arc-shaped pads 12, 13 and 14 is tiltably supported by a pivot (not shown), and these pivots are respectively formed from a vertical plane OX whose center passes through the axis and from this OX. In the figure, they are located on three planes including two planes OY and OZ including the axis OO of the spindle motor and an angle inclination of 130 degrees to the left and right respectively.

Along with the three planes OX, OY, OZ, two cross sections near the longitudinal ends of the arc-shaped pads 12, 13, 14 are respectively formed with high-pressure air jet ports 12 a, which open radially inward. 13a and 14a and 12b, 13b and 14b, and also the end flange 7 and the bearing flange 8 at the free end function as thrust bearings inward in the axial direction High pressure air outlets 7a, 7b, 7c, 8a, 8b and 8c are provided, and the high-pressure air is sent from the inlets 11a, 11b, and 11c to the left in the axial direction through the passage P, is circulated, and flows out from the air chamber 18 on the outer periphery of the fixed shaft. In the figure, reference numeral C ₁ is a gap between the rotor 6 and the arcuate pads 12, 13, 14; reference C ₂ is a clearance between the arcuate pads 12, 13, 14; reference C ₃ is the spindle 6'and the end. A clearance C ₄ with the flange 7 is a clearance between the cylindrical portion 6 a on the opposite side and the bearing flange 8.

[0006]

[Problems to be solved by the device]

 Fig. 4 is a cross-sectional view of the rotor and stator of the outer rotor type spindle motor. The gap between them is, for example, the gap g in the upper part.₁ In contrast, the lower gap is g ₂ Therefore, it was inevitably arranged eccentrically, and it was difficult for the rotor and the stator to be perfectly concentric. In Fig. 4, the degree of this eccentricity is emphasized a little.

By the way, in the case of such an eccentric arrangement, when the eccentricity of the gap between the rotor and the stator is ε and the magnetic flux density of the gap is Bg, the magnetic attraction due to the eccentricity as follows is given. In response to the force (unbalanced magnet pull) F, the part of the stator where the gap is small (g ₂ side) is attracted to the opposing permanent magnets of the rotor, and a bending force is applied to the fixed shaft. F = KBg ² × ε where K is a constant. For this reason, the fixed shaft 1 needs to have an appropriate thickness so as to have rigidity that can withstand this bending force.

Moreover, since the outer rotor type spindle motor has a cantilever system configuration in which the end flange is on the fixed side as shown in the figure (the state is schematically shown in FIG. 5), the fixed shaft 1 Since the amount of bending of the left free end 1a is larger than that of the base, the fixed shaft 1 is required to have a large diameter from the viewpoint of resistance to this bending force, while the fixed shaft 1 is large. When it comes to the diameter, the outer diameter of the rotor 6 is inevitably large. On the other hand, in this type of outer rotor type spindle motor, since the rotor side is driven at a high speed of, for example, tens of thousands of rpm, the outer diameter of the outer periphery of the rotor 6 must withstand such high speed centrifugal force. Of course, in the case of such tens of thousands rpm, the outer diameter of the rotor 6 was limited to a predetermined diameter or less. Therefore, in this type of outer rotor type high-speed rotating electric machine, the fixed shaft 1 must have a small diameter in terms of centrifugal force, while the fixed shaft 1 must have a large diameter in order to have rigidity to withstand bending force. There was a need to solve conflicting problems.

The present invention has been made on the basis of such a point, and an object thereof is to prevent the fixed shaft from bending without increasing the diameter of the fixed shaft, the rotor, and the device. An object is to provide an outer rotor type high-speed rotating electric machine that enables

[0010]

[Means for Solving the Problems]

 In order to achieve the above object, an outer rotor type high-speed rotating electric machine according to the present invention comprises a stator having a fixed shaft and a plurality of stator coils, and a secondary side electric machine arranged around the outer circumference of the stator. A rotor that has a member and that forms a spindle that is coaxial with the fixed shaft and that serves as a rotary shaft; and an end flange on the spindle side and a bearing flange on the opposite side. A casing to be housed in the housing, a support flange adjacent to the outside of the bearing flange in the axial direction for supporting and fixing the fixed shaft, an end flange arranged further outside in the axial direction, the outer circumference of the rotor and the casing. In an outer rotor type high-speed rotating electric machine equipped with a bearing that supports the rotating shaft and is disposed in an annular space between the stator and the rotor, reduce the clearance between the stator and the rotor from the support flange side. Anti-support It is characterized in that it has to become gradually wider toward the Nji side.

[0011]

[Action]

 The gap between the stator and rotor is designed to be smaller on the support flange side and gradually widen from there to the anti-support flange side. As a result, the magnetic imbalance force is strengthened on the support flange side and weakened on the non-support flange side, and the stator shaft of the stator is hard to bend.

[0012]

【Example】

An embodiment of the present invention will be described below with reference to FIG. Incidentally, the same parts as those of the conventional one are designated by the same reference numerals and the description thereof will be omitted. In the case of the present embodiment, the gap between the stator 4 and the rotor 6 is tapered on the side of the support flange 10 so as to gradually increase toward the side opposite to the support flange 10. It is configured in. Concretely, the gap between the iron core 2 of the stator 4 and the permanent magnet 5 of the rotor 6 is tapered. That is, the gap between the support flange 10 side and g _4, when the clearance of the anti-supporting flange 10 side and g _3, together with a relationship of g ₄ <g _3, toward the non-supporting flange 10 side (the left side in the drawing) Is gradually increasing.

With the above structure, the magnetic imbalance force on the support flange 10 side is strengthened, and the magnetic imbalance force on the counter support flange 10 side is weakened. The weaker the magnetic unbalance force is, the more difficult it is for the structure to bend, which prevents the free end 1a of the fixed shaft 1 from bending. Therefore, it is possible to prevent the stator 1 from bending without increasing the diameter of the fixed shaft 1 and the rotor 6 and thus the device.

The present invention is not limited to the above-described embodiment. In the above-described embodiment, the gap between the stator 4 and the rotor 6 is adjusted by adjusting the radial thickness of the stator 4 side. However, the adjustment may be performed by adjusting the thickness of the rotor 6 side or the thicknesses of both. The point is that the gap is relatively small on the support flange 10 side and large on the counter support flange 10 side. The rotary electric machine to which the present invention is applied has a synchronous machine type structure having a permanent magnet like the rotor shown in Fig. 1, and an induction machine including an iron core, a bar and an end ring instead of the permanent magnet. It may be a secondary-side electric machine member having a machine type structure.

[0015]

[Effect of the device]

 As described above in detail, according to the outer rotor type high-speed rotating electric machine of the present invention, the gap between the stator and the rotor is gradually reduced from the support flange side toward the anti-support flange side. With this configuration, the magnetic imbalance force can be increased on the support flange side and weakened on the anti-support flange side, and a structure in which the fixed shaft of the stator is difficult to bend can be obtained. The bending of the fixed shaft 1 can be prevented without increasing the diameter of the child 6 and the device.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of the present invention and is a vertical sectional front view of a main part showing a part of an outer rotor type high speed rotating electric machine.

FIG. 2 is a partially cut front view of an outer rotor type high speed rotating electric machine showing a conventional example.

FIG. 3 is a cross-sectional view taken along line III-III in FIG. 2 showing a conventional example.

FIG. 4 is a sectional view showing an eccentricity of a fixed shaft in a view showing a conventional example.

FIG. 5 is a simplified front view schematically showing a cantilever support structure in a conventional example.

[Explanation of symbols]

 1: Fixed shaft 2: Iron core 3: Coil 4: Stator 5: Permanent magnet (secondary side electric member) 6: Rotor 7: End flange 8: Bearing flange 9: Casing 10: Support flange

Claims (1)

[Scope of utility model registration request] 1. A stator having a fixed shaft and a plurality of stator coils, and a secondary electric machine member disposed around the outer circumference of the stator and having an inner peripheral surface thereof, and rotating coaxially with the fixed shaft. A rotor that forms a spindle that serves as a shaft, a casing that has an end flange on the spindle side and a bearing flange on the opposite side, and that accommodates the stator and the rotor therein, and is adjacent to the outside of the bearing flange in the axial direction. And a supporting flange for supporting and fixing the fixed shaft, an end flange arranged further on the outer side in the axial direction, and a bearing for supporting the rotating shaft arranged in an annular gap between the outer periphery of the rotor and the casing. In the outer rotor type high-speed rotating electric machine equipped with, the gap between the stator and the rotor is made smaller on the support flange side and gradually widens from there to the non-support flange side. Au Tar-rotor type high-speed rotating electric machine.