JP2023042291A - Stator fixing structure for rotary machine and stator fixing method for rotary machine - Google Patents

Abstract

To improve the accuracy of bracket parallelism on a rotary machine of a frameless structure and to achieve the same varnish processing as in the case of a framed structure.SOLUTION: A frameless motor 21 includes a metal rod 26 between intermediate rings 23a, 23b. A stator core 5a is sandwiched between the intermediate rings 23a, 23b. The intermediate ring 23a is formed with a connecting hole 24f connected to a bolt hole 5b. The intermediate ring 23b is formed with a female threaded hole 24d in a location corresponding to the bolt hole 5b. A shaft portion 25b of a through-bolt 25 inserted through the connecting hole 24f and the bolt hole 5b is fastened to the female threaded hole 24d to fix a stator core 5d. When this is done, the portion between intermediate rings 23a, 23b is restricted to the length of a metal rod 26.SELECTED DRAWING: Figure 2

Description

The present invention relates to a technique for fixing a stator to a frameless rotating machine (motor/generator).

1 in FIG. 1A shows an example of an electric motor having a structure with a frame (motor with a frame). Here, a structure is employed in which the frame 2 is attached to the outer periphery of the stator 5, and the frame 2 is sandwiched between brackets 3a and 3b to which the bearings 4 are attached.

However, in a variable speed motor driven by a transistor inverter or the like, it is necessary to sufficiently cool the stator 5 within a range in which the rotor 6 changes from high speed to low speed. Therefore, as shown in Patent Document 1, a frameless structure is used in which the frame 2 is omitted and the stator 5 is exposed.

Reference numeral 11 in FIG. 1(b) indicates an example of a motor having a frameless structure (a frameless motor). Here, a bolt hole 5b is formed in the stator core 5a, the stator core 5a is sandwiched between brackets 13a and 13b, and a through bolt 25 is inserted through the bolt hole 5a and fixed.

Japanese Patent Laid-Open No. 9-219950 JP 2007-295740

According to the frameless structure described above, it is possible to reduce not only the cooling performance but also the cost of motor materials.

However, in the frameless structure, instead of the frame 2 manufactured by machining, the brackets 13a and 13b sandwich the stator core 5a in which the electromagnetic steel plates 5d are laminated. The stator 5 may be tilted depending on the presence or absence of burrs, etc.).

As a result, the accuracy of the parallelism of the brackets 13a and 13b is degraded, and wear of the bearings 4 progresses, which may cause problems such as a shortened product life. In this case, if the stator 5 is an integral iron core, it is possible to improve the parallelism by a technique such as rolling (rotating by 180° and stacking alternately), but this may complicate the work process.

In particular, in the case of split cores as in Patent Literature 2, since the stacking direction is fixed, there are many cases in which it is not possible to rotate the cores. In the frameless structure, the stator core 5a must be varnished before the brackets 13a and 13b are attached. process is required.

SUMMARY OF THE INVENTION The present invention has been made in order to solve such conventional problems. there is

(1) One aspect of the present invention is
a stator disposed on the outer peripheral side of the rotor with a gap therebetween;
a pair of brackets holding bearings of a shaft fixed to the rotor;
an intermediate ring disposed between the bracket and the stator;
with
A stator fixing structure for a rotating machine that fixes the stator between the intermediate rings in a frameless state,
while providing a rod between said intermediate rings;
The stator includes a stator core formed by laminating a plurality of steel plates, and a plurality of bolt holes axially penetrating the stator core,
Both the intermediate rings are formed with a hole communicating with the bolt hole and a female screw,
The distance between the intermediate rings is limited to the length of the rod when the shaft portion of the bolt inserted through the hole and the bolt hole is fastened to the female screw portion.

(2) Another aspect of the present invention is
a stator disposed on the outer peripheral side of the rotor with a gap therebetween;
a pair of brackets holding bearings of a shaft fixed to the rotor;
an intermediate ring disposed between the bracket and the stator;
with
A stator fixing structure for a rotating machine that fixes the stator between the intermediate rings in a frameless state,
while providing a rod between said intermediate rings;
The stator includes a stator core formed by laminating a plurality of steel plates, and a plurality of bolt holes axially penetrating the stator core,
Both the intermediate rings are formed with a hole communicating with the bolt hole and a female screw,
The distance between the intermediate rings is limited to the length of the rod when the shaft portion of the bolt inserted through the bolt hole through the hole portion is fastened to the female screw portion.

(3) Still another aspect of the present invention is a method for fixing the stator core of the other aspect between the intermediate rings,
disposing one of the intermediate rings on one end side of the stator core;
a step of inserting the shaft portion of the bolt into the bolt hole from the other end portion side of the stator core;
a step of fastening the shaft portion to each female thread portion of one of the intermediate rings;
disposing the other intermediate ring on the other end side of the stator core;
mounting the ends of the rods between the intermediate rings;
a step of inserting the shaft portion of the bolt through the hole portion of one of the intermediate rings into the bolt hole of the other intermediate ring;
and a step of fastening the shaft portion to each of the internal thread portions of the other intermediate ring.

According to the present invention, the parallel accuracy of the bracket is improved in a frameless rotating machine, and the stator core can be varnished in the same manner as in the framed structure.

(a) is a vertical cross-sectional view of a conventional framed motor, and (b) is a vertical cross-sectional view of the same frameless motor. 1(a) is a vertical cross-sectional view of a frameless motor employing the stator fixing structure of Embodiment 1, and FIG. 1(b) is a perspective view of a state in which an intermediate ring is attached to the stator. The perspective view of the same stator core (split iron core). (a) is a vertical cross-sectional view of a frameless motor adopting the stator fixing structure of Embodiment 2, and (b) is a front view of an intermediate ring. (a) is a first step drawing of the stator fixing method of FIG. 4 (a), (b) is a second step drawing of the same.

A stator fixing structure (fixing method) for a rotating machine according to an embodiment of the present invention will be described below. This stator fixing structure is applied to a frameless rotating machine similar to that shown in FIG. 1(b).

A first embodiment of the stator fixing structure will be described with reference to FIGS. 2 and 3. FIG. Here, the same components as in FIGS. 1(a) and 1(b) will be described using the same reference numerals.

Reference numeral 21 in FIG. 2(a) denotes a frameless motor employing the stator fixing structure of this embodiment. This frameless motor 21 includes a stator 5 disposed on the outer peripheral side of a rotor 6 with a gap therebetween, a shaft 7 fixed to the rotor 6, brackets 23a and 23b holding bearings 4 of the shaft 7, and a bracket 23a. , 23b and the stator 5, and a metal rod 26 between the intermediate rings 24a, 24b.

The stator 5 includes a stator core 5a in which electromagnetic steel plates 5d are laminated, and a plurality of bolt holes 5b axially penetrating the stay core 5a. As shown in FIG. 3, the stator core 5a includes twelve split cores (split iron cores) 5c in the circumferential direction, and a bolt hole 5b is formed for each split core 5c. The split core 5d is manufactured by laminating electromagnetic steel sheets 5d punched into split pieces of a predetermined shape and integrating them by means of caulking, welding, or the like.

The intermediate rings 24a and 24b are formed in an annular shape as shown in FIG. 2(b) and arranged at both ends of the stator core 5a. The intermediate ring 24a has holes 24c formed at equal intervals along the circumferential direction, while the intermediate ring 24b has female screw holes (tap holes) 24d formed at equal intervals along the circumferential direction. As shown in FIG. 2(a), both 24c and 24d are formed at corresponding positions and communicate with the bolt hole 5b.

Specifically, the hole portion 24c includes a recessed groove 24e formed on the outer surface (facing surface of the bracket 23a) of the intermediate ring 24a, and a communicating hole formed in the groove bottom 24j of the recessed groove 24e and communicating with the bolt hole 5b. 24f.

On the other hand, the female threaded hole 24d is formed on the inner surface of the intermediate ring 24b (the surface facing the stator core 5a). Here, the shaft portion 25b of the through bolt 25 is inserted through the communication hole 24f and the bolt hole 5b through the recessed groove 24c and fastened to the female threaded hole 24d.

Further, a convex boss portion 24g is formed on the outer periphery of the intermediate rings 24a and 24b. A concave portion 24h to which the end portion of the metal rod 26 is attached is formed in the facing surfaces of the boss portions 24g. The ends of the metal rod 26 are held by the recesses 24h, and the metal rod 26 is placed between the intermediate rings 24a and 24b.

According to the stator fixing structure as described above, the fixing operation of the stator 5 is performed in the following steps. First, the stator 5 is placed between the intermediate rings 24a and 24b, and the metal rods 26 are attached to the recesses 24h. Next, the shaft portion 25b of the bolt 25 is inserted through the groove 24c into the communication hole 24f and the bolt hole 5b, and the tip of the shaft portion 25b is fastened to the female screw hole 24d.

That is, as the shaft portion 25b is screwed into the female threaded hole 24d, the head portion 25a of the through-bolt 25 presses the groove bottom 24j (the inner peripheral edge of the communication hole 24f) of the recessed groove 24e. It is sandwiched and fixed between 24a and 24b.

At this time, the stator core 5a is tightened between the intermediate rings 24a and 24b, but since the metal rods 26 are stretched, the distance between the intermediate rings 24a and 24b is limited to the length of the metal rods 26 in the axial direction. Therefore, the distance between the intermediate rings 24a, 24b depends on the precision of the machined metal rods 26 rather than the length of the stator core 5a (iron core length).

As a result, even if there is some deviation in the iron core length due to the accuracy of the magnetic steel plate 5b (existence of burrs, etc.), if the metal rod 26 is tightened to the length, the intermediate rings 24a and 24b can be prevented from tilting. This makes it possible to maintain high-precision parallelism for the intermediate rings 24a and 24b.

After the intermediate rings 24a and 24b are attached, post-processing of the spigot (inserted structure) of the intermediate rings 24a and 24b can be performed to achieve more accurate parallelism and concentricity. Therefore, the accuracy of the parallelism of the brackets 23a and 23b is improved, and in this respect the problem of the product life such as progress of wear of the bearing 4 is resolved.

In addition, since the stator core 5a can be impregnated with varnish while the intermediate rings 24a and 24b are attached, it is possible to impregnate the stator core 5a with varnish before attaching the brackets 23a and 23b as in the case of the framed motor 1. As a result, there is no need to carry out a complicated process such as dripping and impregnating varnish from the inside of each split core 5c as in the conventional art, and varnishing can be simplified.

A first embodiment of the stator fixing structure will be described with reference to FIGS. 4 and 5. FIG. Reference numeral 31 in FIG. 4(a) denotes a frameless motor employing the stay fixing structure of this embodiment.

The frameless motor 31 is provided with intermediate rings 34a and 34b instead of the intermediate rings 24a and 24b. The intermediate rings 34a and 34b are formed with large-diameter hole portions (bump holes) 34c and female screw holes 24d alternately and equally spaced along the circumferential direction.

The hole portion 34c and the female screw hole 24d are formed at positions corresponding to the intermediate rings 24a and 24b, respectively. FIG. 4(b) shows the formation positions of the hole portion 34c and the female screw hole 24d of the intermediate ring 34a. On the other hand, the intermediate ring 34b has a female threaded hole 24d formed at a position corresponding to the hole 34c of the intermediate ring 34a, and a hole 34c formed at a position corresponding to the female threaded hole 24d of the intermediate ring 34a.

Here, the intermediate rings 34a and 34b are each formed with six holes 34c and six female screw holes 24d. The diameter of the hole portion 34c is formed larger than the diameters of the head portion 5a of the bolt 5 and the bolt hole 5b, and the hole portion 34c and the female screw hole 24d are formed to communicate with each other at a position corresponding to the bolt hole 5b. Since the bolt hole 5b is formed for each split core 5c, the intermediate rings 34a and 34b are formed with a hole portion 34c/female screw hole 25d for each split core 5c.

Then, the shaft portion 25b of the bolt 25 is inserted through the bolt hole 5b through the hole portion 34c of the intermediate rings 34a, 34b and fastened to the respective female screw holes 24d so that each split core 5c is connected to the intermediate rings 34a . It is sandwiched and fixed between 34b.

≪How to fix the stator≫
The steps of the stator fixing method according to this embodiment will be described with reference to FIG. Arrow P in FIGS. 5A and 5B indicates one end side of the stator core 5a, and arrow Q indicates the other end side of the stator core 5b.

First step: As shown in FIG. 5(a), the intermediate ring 34b is arranged on the arrow P side of the stator core 5a. In this state, the shaft portions 25b of the six through bolts 25 are inserted from the arrow Q side into the bolt holes 5b of the intermediate ring 34b. The stator core 5a is fixed to the intermediate ring 34b by fastening the tip of the shaft portion 25b inserted here to the female screw hole 25d of the intermediate ring 34b.

Second step: As shown in FIG. 5(b), the state shown in FIG. 5(a) is rotated 180° to dispose the intermediate ring 34a on the arrow Q side of the stator core 5a, and the concave portions 24h of both intermediate rings 34a and 34b are arranged. Both ends of the metal rod 26 are attached to the . In this state, the shafts 25b of the six bolts 25 are inserted from the arrow P side into the bolt holes 5b of the intermediate ring 34b through the holes 34c of the intermediate ring 34b. Here, the tip of the inserted shaft portion 25b is fastened to the female screw hole 25d of the intermediate ring 34a.

As a result, each split core 5c of the stator core 5a is sandwiched and fixed between the intermediate rings 34a and 34b. At this time, if the metal rod 26 is tightened up to the length, the inclination of the intermediate rings 34a, 34b can be prevented, and in this respect, the same effect as in the first embodiment can be obtained.

Here, in the fixing structure of the first embodiment, since the split cores 5c are tightened between the intermediate rings 24a and 24b, there is a possibility that the tightening of the stator core 5a may be loosened due to the difference in axial length between the split cores 5c.

On the other hand, in this embodiment, since the head 25a of the bolt 25 directly tightens the inner peripheral edge of the bolt hole 25b of each split core 25c, loosening of the electromagnetic steel plate 5d due to the sound and vibration of the motor 31 can be suppressed. can be done. As a result, low noise and low vibration of the motor 31 can be realized, and excellent effects can be obtained particularly in the case of split cores.

It should be noted that the present invention is not limited to the above-described embodiments, and can be modified and implemented within the scope described in each claim. For example, the stator core 5a of the present invention is not limited to the case of split cores, and may be configured with an integral core.

However, in the fixing structure of the second embodiment, the head 25a of the bolt 25 directly tightens the inner peripheral edge of the bolt hole 5b, so the laminated magnetic steel sheets (stator core 5a) may undulate in the case of the integral iron core. In this case, it is preferable to adjust the amount of tightening of each bolt 25 so as to achieve uniformity.

Further, the hole portion 24c of the first embodiment does not necessarily have to be formed in a two-stage hole, and the communication hole 24f may be formed through the intermediate ring 24a.

DESCRIPTION OF SYMBOLS 4... Bearing 5... Stator 5a... Stator core 5b... Bolt hole 5c... Split core 5d... Electromagnetic steel plate 6... Rotor 7... Shaft 21, 31... Frameless motor 23a, 23b... Bracket 24a, 24b, 34a, 34b... Intermediate ring 24c , 34c... Hole portion 24d... Female screw hole (female screw portion)
24e... concave groove 24f... communicating hole 24g... boss portion 24h... concave portion (holding portion)
25 ... through bolt (bolt)
25a... Head 25b... Shaft 26... Metal rod (rod)

Claims (7)

a stator disposed on the outer peripheral side of the rotor with a gap therebetween;
a pair of brackets holding bearings of a shaft fixed to the rotor;
an intermediate ring disposed between the bracket and the stator;
with
A stator fixing structure for a rotating machine that fixes the stator between the intermediate rings in a frameless state,
while providing a rod between said intermediate rings;
The stator includes a stator core formed by laminating a plurality of steel plates, and a plurality of bolt holes axially penetrating the stator core,
Both the intermediate rings are formed with a hole communicating with the bolt hole and a female screw,
A stator fixing structure for a rotating machine, wherein a distance between the intermediate rings is limited to a length of the rod when a shaft portion of a bolt inserted through the hole and the bolt hole is fastened to the female thread portion. The diameter of the hole is smaller than the diameter of the head of the bolt,
The stator fixing structure for a rotating machine according to claim 1, wherein the stator core is fixed between the intermediate rings by tightening the inner peripheral edge of the hole with the head. a stator disposed on the outer peripheral side of the rotor with a gap therebetween;
a pair of brackets holding bearings of a shaft fixed to the rotor;
an intermediate ring disposed between the bracket and the stator;
with
A stator fixing structure for a rotating machine that fixes the stator between the intermediate rings in a frameless state,
while providing a rod between said intermediate rings;
The stator includes a stator core formed by laminating a plurality of steel plates, and a plurality of bolt holes axially penetrating the stator core,
Both the intermediate rings are formed with a hole communicating with the bolt hole and a female screw,
A stator fixation for a rotating machine, wherein a distance between the intermediate rings is limited to the length of the rod when a shaft portion of a bolt inserted through the bolt hole through the hole portion is fastened to the female thread portion. structure. The diameter of the hole is formed larger than the diameter of the head of the bolt,
The stator fixing structure for a rotating machine according to claim 3, wherein the stator core is fixed to the intermediate ring by the head tightening the inner peripheral edge of the bolt hole. The stator core includes a plurality of split cores in the circumferential direction,
5. The stator fixing structure for a rotating machine according to claim 3, wherein the hole and the female screw are formed for each of the split cores. The stator fixing structure for a rotating machine according to any one of claims 1 to 5, wherein the intermediate ring is formed with a holding portion for mounting and holding the end portion of the rod. 5. A method for fixing the stator core between the intermediate rings according to claim 3 or 4,
disposing one of the intermediate rings on one end side of the stator core;
a step of inserting the shaft portion of the bolt into the bolt hole from the other end portion side of the stator core;
a step of fastening the shaft portion to each female thread portion of one of the intermediate rings;
disposing the other intermediate ring on the other end side of the stator core;
mounting the ends of the rods between the intermediate rings;
a step of inserting the shaft portion of the bolt through the hole portion of one of the intermediate rings into the bolt hole of the other intermediate ring;
a step of fastening the shaft portion to each of the internal thread portions of the other intermediate ring;
A stator fixing method for a rotating machine, comprising:

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