WO2015163640A1

WO2015163640A1 - Rotor of motor

Info

Publication number: WO2015163640A1
Application number: PCT/KR2015/003792
Authority: WO
Inventors: 최진우; 김민수
Original assignee: 주식회사 효성
Priority date: 2014-04-21
Filing date: 2015-04-15
Publication date: 2015-10-29
Also published as: KR101611492B1; KR20150121774A

Abstract

The present invention relates to a rotor of a motor in which a plurality of rotor cores having barriers are stacked, and press-fitted into and coupled to the outer peripheral surface of a rotary shaft, wherein a deformation-preventing hole for preventing deformation during press-fitting is formed at one side of each rotor core, so as to prevent the deformation of the rotor during assembly, thereby reducing a torque ripple, noise, and vibration.

Description

Rotor of motor

The present invention relates to a rotor of a motor, and more particularly to a rotor of a motor in which the rotor is assembled by shrinking the rotation shaft.

In general, a motor includes a stator in which a coil that generates magnetism by electricity is rotated, and a rotor that is rotated by mutual electromagnetic force with the stator.

The motor may be divided into a core type having a rotor and a stator inside and outside along a radial direction of the rotation shaft, and a coreless type in which the rotor and stator are arranged in the axial direction of the rotation shaft.

Among the core motors, the synchronous reluctance motor is operated at a synchronous speed by the reluctance torque generated due to the difference Ld-Lq of the d-axis inductance Ld and the q-axis inductance Lq. It is a rotating synchronous motor.

Synchronous reluctance motors are cheaper and more reliable than other types of motors, have a very long lifetime, have good electromagnetic properties, but have disadvantages in terms of noise and vibration.

1 to 2, the conventional synchronous inductive reluctance motor is provided with a stator 120 connected to an external power source and rotatably provided inside the stator 120 to supply power to the stator 120. If it is started by the induced electromotive force is made of a rotor (rotor 110) and the like rotated at a synchronous speed by the reluctance torque (Reluctance Torque).

The rotor 110 is formed after the shaft hole 115 is formed in the center and a plurality of rotor cores in which a plurality of flux barriers 111 are formed around the shaft hole 115. The electron 110 is pressed into the rotating shaft 130 by shrinking and assembled.

That is, a slip may occur in a process in which the rotor 110 is assembled with the rotating shaft 130. In order to prevent this, the outer diameter of the rotating shaft 130 is made larger than the inner diameter of the rotor 110, and silicon is manufactured. The rotor 110 made of steel sheet is coupled to the rotating shaft 130 in the expanded state by heating, and then contracted and fixed after cooling.

This has the advantage of being firmly fixed, but according to the shrink fit process, local stress concentrations occur inside the rotor barrier and deformation occurs in the rotor 110, thereby causing an air gap between the stator 120 and the rotor 110. gap) becomes non-uniform, resulting in increased torque ripple, noise and vibration.

Since the air gap between the stator 120 and the rotor 110 varies greatly along the circumferential direction according to the deformation distribution of the rotor 110, conventionally, the outer diameter of the rotor 110 is sanded, etc. Although some methods have been used, this has not been the fundamental countermeasure to solve the nonuniformity.

The present invention was created to improve the problems of the rotor of the conventional motor as described above, by minimizing deformation of the outer diameter of the rotor by ensuring a safety factor by uniformly distributing the local stress concentration region occurring inside the rotor barrier An object of the present invention is to provide a rotor of a motor capable of reducing torque ripple and reducing noise and vibration by reducing an uneven portion of the air gap between the stator and the rotor.

In order to achieve the above object, the rotor of the motor according to the present invention is a rotor of a motor in which a plurality of rotor cores formed with barriers are stacked and press-fitted to an outer circumferential surface of a rotating shaft, and one side of each rotor core. It characterized in that the deformation preventing hole for preventing the deformation during the press-fit in the formed.

In the rotor of the motor according to an embodiment of the present invention, the barriers are provided with a predetermined distance from each other along the radial direction of the rotation axis to form a barrier group, a plurality of barrier groups provided with a predetermined interval along the circumferential direction The deformation preventing hole is provided between the barrier groups.

In the rotor of the motor according to the embodiment of the present invention, the deformation preventing hole is formed symmetrically about the d-axis dividing the space between the barrier groups.

In the rotor of the motor according to an embodiment of the present invention, the deformation preventing hole may be formed in a triangular shape.

In the rotor of the motor according to an embodiment of the present invention, the deformation preventing hole is a first inner wall formed in a direction transverse to the radial direction of the rotation axis, and a barrier provided symmetrically about the d axis and adjacent to the rotation axis It may include a pair of second inner side wall formed in parallel with.

In the rotor of the motor according to an embodiment of the present invention, the first inner wall of the deformation preventing hole may be formed in an arc shape along the circumferential direction of the rotation shaft.

In the rotor of the motor according to an embodiment of the present invention, the barrier may be formed in a straight line across the radial direction of the rotation axis.

In the rotor of the motor according to the embodiment of the present invention, the shortest distance M between two adjacent deformation preventing holes is L / with respect to the length L of the barrier parallel to the first inner wall of the deformation preventing hole. It is preferable to satisfy 3 <M <2L / 3.

In the rotor of the motor according to the embodiment of the present invention, the angle α between the first inner side wall and the second inner side wall satisfies 10 degrees <α <60 degrees.

The features and advantages of the present invention will become more apparent from the following detailed description based on the accompanying drawings.

As described above, according to the rotor of the motor according to the present invention, the stress concentration portion generated inside the rotor barrier according to the shrink fit process to ensure structural stability and thereby to secure the rotor optimum design margin Since the length of the iron heart can be reduced compared to the same output, the cost of the rotor electrical steel sheet can be reduced and the efficiency can be improved.

In addition, by preventing deformation of the rotor, an air gap is uniformly distributed between the rotor and the stator, and torque ripple can be reduced, as well as noise and vibration can be reduced.

According to the present invention, by forming a hole in the rotor, the weight can be reduced, and the stress generated in the rotor can be dispersed to increase the structural stability.

1 is a side view showing a synchronous reluctance motor according to the prior art;

FIG. 2 is a partially enlarged view of the rotor core of FIG. 1. FIG.

Figure 3 is a side view showing a rotor of the motor according to an embodiment of the present invention.

4 is a partially enlarged view of FIG. 3.

Figure 5 is a structural analysis showing the rotor stress gradient of the motor according to the prior art.

Figure 6 is a structural analysis showing the rotor stress gradient of the motor according to an embodiment of the present invention.

Figure 7 is a structural analysis showing the uniformity through the rotor outer diameter deformation analysis of the motor according to the prior art.

Figure 8 is a structural analysis showing the uniformity through the rotor outer diameter deformation analysis of the motor according to an embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

3 to 4, a rotor of a motor according to an embodiment of the present invention includes a plurality of rotor cores 10 stacked on top of each other, and the stacked rotor cores 10 of the rotating shaft 40 are provided. It is press-fitted to the outer circumference and combined.

A plurality of barriers 20 are formed at one side of each rotor core 10.

The barriers 20 are provided with a predetermined distance from each other along the radial direction of the rotation axis 40 to form a barrier group (B), a plurality of barrier groups (B) are provided with a predetermined interval along the circumferential direction. .

As shown in FIG. 3, the d-axis is a direction line that bisects the space between the barrier groups B among the direction lines extending along the radial direction from the center of the rotation axis 40, and the q-axis is the barrier 20. It is the center line that bisects them.

The barrier 20 includes a first barrier 21 formed in a straight line across the radial direction of the rotation shaft 40, and a pair of second barriers 22 provided at both ends of the first barrier 21. .

The first barrier 21 is formed in a straight line perpendicular to the q axis, and the second barrier 22 is bent at a predetermined angle with respect to the first barrier 21. The first barrier 21 and the second barrier 22 may be formed in a curved shape rather than in a straight line, or the first barrier 21 and the second barrier 22 may be formed so as not to be continuous. Included in the category.

One side of each rotor core 10 is formed with a deformation preventing hole 30 for preventing deformation during press-fitting.

The deformation preventing hole 30 is provided on the d-axis, and is formed symmetrically about the d-axis.

The deformation preventing hole 30 is formed of a first inner side wall 31 and a pair of second inner side walls 32 to form a triangular shape as a whole. Here, the first inner side wall 31 and the pair of second inner side wall 32 may both be formed of a linear line segment, and in this case, the sum of the inner angles forms a geometric triangle of 180 degrees. In addition, the first inner side wall 31 and the pair of second inner side wall 32 are both curved, not line segments, and although not geometrically triangular in shape, they are generally included in the scope of the present invention. to be.

In the present embodiment, the first inner side wall 31 is formed in an arc shape, and the second inner side wall 32 is formed in a straight line.

The first inner side wall 31 is formed in a direction transverse to the radial direction of the rotation shaft 40 is formed in an arc shape along the circumferential direction of the rotation shaft 40. The first inner side wall 31 is formed to be symmetrically divided about the d axis.

The second inner wall 32 is formed in parallel with the first barrier 21. When the first barrier 21 is formed in a straight line, the second inner wall 32 is also formed in a straight line and provided in parallel with each other. The second inner side walls 32 are provided symmetrically with respect to the d axis one by one.

The deformation preventing hole 30 forms a space between the barrier 20 and the shaft hole 15 so that the portion between the shaft hole 15 and the first inner side wall 21 is not transferred to the barrier 20 even when the portion between the shaft hole 15 and the first inner wall 21 is deformed. do. Therefore, the shape and position of the deformation preventing hole 30 is the main variable to absorb the deformation.

As shown in FIG. 4, the length of the barrier 20 that is closest to the rotation axis 40 among the plurality of barriers 20 constituting one barrier group B is referred to as L, and one barrier group B is used. When the distance between the pair of strain relief holes 30 formed on both sides of the side is M, the shortest distance M between two adjacent strain prevention holes 30 is L / 3 <M <2L / 3 To satisfy.

That is, the distance M between the first inner side walls 31 of two adjacent deformation preventing holes 30 is predetermined with respect to the length L of the barrier 20 that is closest to the deformation preventing hole 30. Has a distance ratio of. When the shortest distance M between the strain preventing holes 30 is smaller than L / 3, the area occupied by the strain preventing holes 30, which is an empty space, is too large and the strength of the rotor core 10 is lowered. When the deformation is greater than 2L / 3, the area occupied by the deformation preventing hole 30 is too small, so that the effect of reducing deformation during indentation and assembly is reduced, and the stress gradient is uniform in the generation of local stress. The effect is reduced.

As shown in FIG. 4, the angle α between the first inner side wall 31 and the second inner side wall 32 of the deformation preventing hole 30 is preferably greater than 10 degrees and smaller than 60 degrees. That is, the deformation preventing hole 30 is preferably formed with the first inner side wall 31 and the second inner side wall 32 to satisfy 10 degrees <α <60 degrees.

When the angle α is smaller than 10 degrees, the triangular corner where the first inner wall 31 and the second inner wall 32 meet is too sharp, so that the first inner wall 31 is deformed by the deformation of the barrier 20. ) May be affected, and if the angle (α) is greater than 60 degrees, the length of the first inner wall 31 becomes too short, so that the shortest distance (M) condition between the strain preventing holes 30 is determined. By not being able to be satisfied, the effect of reducing deformation is greatly reduced. The angle between the angles shown in FIG. 4 is 30 degrees.

Figure 5 shows the stress gradient of the rotor during the conventional indentation assembly without the deformation prevention hole 30, Figure 6 shows the stress gradient of the rotor of the present invention to which the deformation prevention hole 30 is applied. Table 1 below shows the results of FIGS. 5 and 6.

Table 1

Referring to FIGS. 5 and 6, a portion indicated in red is a portion having high stress, and a portion indicated in blue is a portion having the lowest stress.

When there is no deformation preventing hole 30, the stress is 323.6MPa, when the deformation preventing hole 30 is 266.6MPa it can be seen that the stress is reduced by 20% or more.

In this way, the strain-resistant holes are applied to the inner side of the core before the strain-resistant holes are applied, thereby dispersing the concentrated stress so that the stress can be uniformly distributed.

Through this, it is possible to reduce the bottom barrier distance by securing the rotor barrier design margin, thereby reducing the length of the iron heart of the rotor compared to the same output, thereby reducing the cost of the electrical steel sheet of the rotor and improving the efficiency. do.

Figure 7 shows the deformation amount during the press-fit assembly of the conventional rotor without the deformation prevention hole 30, Figure 8 shows the deformation amount of the rotor of the present invention to which the deformation prevention hole 30 is applied. Table 2 below shows the results of FIGS. 5 and 6.

TABLE 2

Referring to FIGS. 7 and 8, the portion marked in red is the portion where the air gap between the stator and the rotor is the largest, and the deformation amount of the rotor core is the smallest. It is a small part (Min).

In the absence of the deformation preventing hole 30, the difference between the maximum value (0.041153 mm) and the minimum value (0.020288 mm) of the air gap is 0.020865 mm.

On the other hand, referring to Figure 8 and Table 2, in the case of the present invention to which the deformation prevention hole 30 is applied, the difference between the maximum value (0.023735) and the minimum value (0.012166mm) is only 0.011569mm. This means that the variation of the rotor core 10 is not only uniformly deformed but also significantly reduced. As such, the uniformity of the air gap is improved, thereby reducing torque ripple, noise, and vibration of the motor, thereby improving performance of the motor.

Although the present invention has been described in detail through specific examples, it is intended to specifically describe the present invention, and the present invention is not limited thereto, and the present invention has ordinary knowledge in the art within the technical spirit of the present invention. It is obvious that the modification or improvement is possible by the ruler.

All simple modifications and variations of the present invention fall within the scope of the present invention, and the specific scope of protection of the present invention will be apparent from the appended claims.

Claims

In a rotor of a motor in which a plurality of rotor cores formed with barriers are stacked and press-fitted to an outer circumferential surface of a rotating shaft,

The rotor of the motor, characterized in that the deformation preventing hole for preventing the stress distribution and deformation inside the barrier when indented on one side of each rotor core.
The method of claim 1,

The barriers are provided with a predetermined distance from each other along the radial direction of the rotation axis to form a barrier group, a plurality of barrier groups are provided with a predetermined interval along the circumferential direction,

The deformation preventing hole is a rotor of the motor, characterized in that provided between the barrier groups.
The method of claim 2, wherein the deformation preventing hole,

The rotor of the motor, characterized in that formed symmetrically about the d axis dividing the space between the barrier groups.
The method of claim 3, wherein the deformation preventing hole,

Rotor of the motor, characterized in that formed in a triangular shape.
The method of claim 4, wherein the deformation preventing hole,

A first inner wall formed in a direction transverse to the radial direction of the rotation shaft; And

And a pair of second inner walls provided symmetrically about the d axis and formed in parallel with a barrier adjacent to the rotation axis.
The method of claim 5, wherein the first inner side wall of the deformation preventing hole,

The rotor of the motor, characterized in that formed in an arc shape along the circumferential direction of the rotation axis.
The method of claim 5,

The barrier is formed in a straight line across the radial direction of the axis of rotation,

A motor characterized in that the shortest distance M between two adjacent deformation preventing holes satisfies L / 3 <M <2L / 3 with respect to the length L of the first inner wall of the deformation preventing hole and the adjacent barrier. Rotor.
The method of claim 5,

The angle α between the first inner side wall and the second inner side wall satisfies 10 degrees < α <60 degrees.