JP4244111B2 - Permanent magnet synchronous motor rotor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a rotor of a permanent magnet type synchronous motor, and more particularly to a rotor structure having a permanent magnet inside a rotor core designed to withstand high-speed rotation.
[0002]
[Prior art]
Conventionally, a rotor of a permanent magnet type synchronous motor provided with a permanent magnet inside a rotor core is as shown in FIG. FIG. 3 is a cross-sectional view of the permanent magnet type synchronous motor showing the first prior art. For convenience, the explanation will be made with an actual rotor and stator cut into a quarter. In the figure, 1 is an armature, 2 is a status lot, 3 is a winding, 4 is a rotating shaft, 5 is a rotor, 51 is a rotor core, 51A is a shaft hole, 52 and 53 are rotor slots, 52A, 52B, 52C and 52D. 53A, 53B, 53C and 53D are corners, 54 is a salient pole part, 55 is a bridge, 56 and 57 are thin wall parts, 58 and 59 are punched holes, and 6A and 6B are permanent magnets. A rotor core 51 made of laminated electromagnetic steel sheet is provided through an air gap on the inner diameter of an armature 1 formed by winding a multiphase / multipolar winding 3 in a status lot 2 formed on a core made of laminated electromagnetic steel sheet. is there. Holes 58 and 59 for preventing leakage magnetic flux are provided in both wing portions of the rotor core 51. Further, the rotor core 51 is divided into left and right portions so as to leave the central portion of the rotor core 51 between the punched holes 58 and 59, and rectangular rotor slots 52 and 53 having a width slightly narrower than the pole pitch are provided. , 53 are fitted with a pair of rectangular field permanent magnets 6A, 6B, and the upper surfaces of the field permanent magnets 6A, 6B are configured as salient pole portions 54. The field permanent magnets 6A and 6B are magnetized in the radial direction so that the rotor slots 52 and 53 are equal in thickness and width and have the same polarity. Further, between the rotor slots 52 and 53, the salient pole portion 54 and the rotor slots 52 and 53 are formed so as to be connected, and a bridge 55 for dividing the pole between the permanent magnets 6A and 6B is provided. Thin portions 56 and 57 are provided between the punch holes 58 and between the permanent magnet 6B and the punch holes 59, respectively, and the width of the fridge 55 and the thin portions 56 and 57 maintains the mechanical strength and is electromagnetically magnetic. The value is set so that the road is saturated.
[0003]
In the prior art, when the bridge 55 exists between the rotor slots 52 and 53 of the rotor core 51 or the thin portions 56 and 57 exist, the corners 52A, 52B, 53A, 53B, 52C and 52D are also present on the thin portion 56 side, and 53C and 53D are also present on the thin portion 57 side. In particular, stress concentration appears at these corners due to the influence of the fitting portion between the shaft hole 51A and the rotating shaft 4. In consideration of this point, the shaft hole 51A and the rotating shaft 4 are rotated in order to rotate the rotor 5 at high speed. The tightening allowance of the interference fit in the fitting portion is at least a length dimension equal to or greater than the radial expansion of the shaft hole 51A due to rotation minus the radial expansion of the rotation shaft 4 due to rotation, In order to achieve high-speed rotation of the rotor, it is necessary to make a large allowance for the interference fit between the shaft hole 51 </ b> A and the rotating shaft 4.
[0004]
[Problems to be solved by the invention]
However, in the first prior art, in the corner portions 52B and 53B, the stress concentration particularly in the corner portions 52B and 53B appears greatly due to the effect of the interference fit between the shaft hole 51A and the rotary shaft 4, There is a problem that the shapes of the portions 52B and 53B become a limitation when determining the interference of the interference fit between the shaft hole 5 and the rotary shaft 6, and consequently the rotational speed of the rotor 5. The corners 52C and 53C also have the same problem as the corners 52B and 53B.
[0005]
In order to solve the above-described problem of the first prior art, another permanent magnet type synchronous motor rotor has been proposed. 4A and 4B show a permanent magnet type synchronous motor showing the second prior art, in which FIG. 4A is a cross-sectional view thereof, and FIG. 4B is an enlarged view illustrating the position of a clearance portion of the rotor slot of FIG. . As in FIG. 3, the rotor and stator are cut into quarters. In the figure, the second prior art reduces the stress concentration at the corners due to the effect of the interference fit between the shaft hole 51A and the rotary shaft 4 which is a problem in the first prior art. The corners 52B, 52D, 53B, 53D of 52 and 53 are formed with relief portions 52L, 52N, 53L, 53N that are formed in a semicircular shape with a certain radius toward the shaft hole 51A side, and the other The relief portions 52K, 52M, 53K, and 53M are formed in the corner portions 52A, 52C, 53A, and 53C in the same semicircular shape toward the salient pole portion 54 side. However, even in such a configuration, the corners 52B and 53B close to the shaft hole 51A exhibit particularly large stress concentration due to the effect of the interference fit between the shaft hole 51A and the rotary shaft 4, so that the relief portions 52L and 52N , 53L, and 53N have dimensional constraints even when the radius is increased toward the shaft hole. The present invention has been made to solve the above problems, and provides a rotor of a permanent magnet type synchronous motor that can reduce stress concentration due to centrifugal force at the corners of the rotor slot and maintain the strength of the rotor core during high-speed rotation. The purpose is to do.
[0006]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the present invention according to claim 1 prevents a rotor core made of laminated electromagnetic steel sheets, a rotating shaft fitted in a shaft hole of the rotor core, and leakage magnetic flux provided in both blade portions of the rotor core. And a rectangular rotor slot which is provided so as to leave a central portion of the rotor core between the punched holes and which is divided into right and left, and a rectangular shape fitted into the rotor slot. A permanent magnet, a salient pole formed on an upper surface of the field permanent magnet, and a bridge formed so as to connect the salient pole and the rotor core between the rotor slots. of the relief portion formed toward the shaft hole side corner, in the rotor of the other corner portions a permanent magnet synchronous motor provided with a relief portion formed toward the salient pole portion side, you said rotor slot That the bridge side and relief portion formed in the shaft hole side, so as to disperse the stress is concentrated in one place該逃up part, compared to other relief in the shape, the longitudinal direction of the rotor slot bottom And a rectangular bulge that swells greatly outside the slot . By the above means, when the relief portions formed on the bridge side and the shaft hole side of the rotor slot are formed larger along the longitudinal direction of the bottom portion of the rotor slot than the other relief portions, the field permanent magnet and the rotor slot The stress concentration at the corner is distributed on the shaft hole side of the relief,
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view of a permanent magnet type synchronous motor showing a first embodiment of the present invention. In addition, about the same component as this invention, the same code | symbol is attached | subjected and description is abbreviate | omitted and only a different point is demonstrated. In the figure, 52E, 53E, 52F, and 53F are steps. The present invention is different from the first prior art as follows. That is, each of the rotor slots 52 and 53 draws a substantially arc-shaped locus toward the bridge 55 between the vicinity of the center of the end on the bridge 55 side and the corners 52B and 53B located at the bottom of the slot. This is the point where protruding steps 52E and 53E are provided. Further, on the side of the thin portions 56 and 57 of the rotor slots 52 and 53, the thin portions 56 are provided between the vicinity of the center of the end portions of the rotor slots 52 and 53 and the corner portions (52C and 53C) located at the tips of the slots. , 57 is provided with protruding steps 52F and 53F that draw a substantially arc-shaped locus toward the 57 side.
[0008]
Next, when applying the rotor of the permanent magnet type synchronous motor according to the present invention, the stress change rate was analyzed by FEM analysis. According to this, the corners 52B and 53B of the rotor slots 52 and 53 conventionally have an arc radius of 0.3 mm, and by applying 1.55 mm of the present invention, the vicinity of the corners 52B and 53B is obtained. As a result, the rate of change in stress decreased to 0.78 compared to the conventional case, and the effect of stress relaxation could be confirmed. In addition, with respect to the corner portions 52C and 53D of the rotor slots 52 and 53, it was possible to confirm the effect of stress relaxation by reducing the rate of change in stress by making the same improvements as the arc radii of the corner portions 52B and 53B. .
[0009]
Therefore, steps 52E and 53E projecting toward the bridge 55 are provided between the vicinity of the center of the end of each rotor slot 52 and 53 on the bridge 55 side and the corners 52B and 53B located at the bottom of the slot. Therefore, during high-speed rotation, the stress concentration due to the centrifugal force at the corners 52B and 53B of the rotor slots 52 and 53 can be dispersed, and as a result, due to the effect of the interference fit between the shaft hole 51A and the rotary shaft 4 The stress concentration is reduced and the strength of the rotor core can be maintained. Further, the rotor slots 52, 53 protrude toward the thin portions 56, 57 between the vicinity of the center of the end portions on the thin portions 56, 57 side and the corner portions 52C, 53C located at the tips of the slots. Since the steps 52F and 53F are provided, stress concentration due to centrifugal force at the corners 52C and 53C of the rotor slots 52 and 53 can be dispersed during high-speed rotation. As a result, the interference fit between the shaft hole 51A and the rotating shaft 4 is achieved. The stress concentration due to the influence of the engagement is reduced, and the strength of the rotor core can be maintained.
[0010]
Next, a second embodiment of the present invention will be described. FIGS. 2A and 2B show a permanent magnet type synchronous motor according to a second embodiment of the present invention, in which FIG. 2A is a cross-sectional view thereof, and FIG. 2B is an enlarged view illustrating the position of a clearance portion of a rotor slot of FIG. FIG. As in the first embodiment, the same components as those of the prior art according to the present invention are denoted by the same reference numerals, description thereof is omitted, and only different points will be described. The second embodiment of the present invention is different from the second prior art as follows. That is, the shapes of the relief portions 52L and 53L formed on the bridge 55 side and the shaft hole 51A side are compared with the shapes of the other relief portions 52K, 52M, 52N, 53K, 53M, and 53N, and the bottom portions of the rotor slots 52 and 53 are compared. It is the point enlarged along the longitudinal direction.
[0011]
Next, when applying the rotor of the permanent magnet type synchronous motor according to the present invention, the stress change rate was analyzed by FEM analysis. According to this, as a result of applying the relief portions 52L and 53L formed on the bridge 55 side and the shaft hole 51A side of the present invention, the stress change rate in the vicinity of the corner portions 52B and 53B is reduced to 0.8 compared to the conventional case. Was obtained, and the effect of stress relaxation could be confirmed.
[0012]
Therefore, the shapes of the relief portions 52L and 53L formed on the bridge 55 side and the shaft hole 51A side are compared with the shapes of the other relief portions 52K, 52M, 52N, 53K, 53M, and 53N, and the bottom portions of the rotor slots 52 and 53 are compared. Therefore, the stress concentration due to the centrifugal force at the corners 52B and 53B of the rotor slots 52 and 53 can be dispersed during high-speed rotation. As a result, if the shaft hole 51A and the rotary shaft 4 are tightened, The stress concentration due to the influence of the fitting is reduced, and the strength of the rotor core can be maintained.
[0013]
【The invention's effect】
As described above, according to the first embodiment of the present invention, the bridge of each rotor slot protrudes toward the bridge between the vicinity of the center of the rotor slot and the corner located at the bottom. As a result, the stress concentration due to centrifugal force at the corners of the rotor slot can be dispersed during high-speed rotation. As a result, the stress concentration due to the interference fit between the shaft hole and the rotary shaft is reduced. The strength of the rotor core can be maintained while being reduced. In addition, since a step is provided on the side of the rotor slot of each rotor slot between the vicinity of the center of the rotor slot and the corner portion positioned at the tip, the step protrudes toward the thin wall portion side. Stress concentration due to centrifugal force at the corners can be dispersed. As a result, stress concentration due to the effect of the interference fit between the shaft hole and the rotary shaft can be reduced, and the strength of the rotor core can be maintained. . Thus, a rotor of a permanent magnet type synchronous motor that can withstand high-speed rotation can be realized. Further, according to the second embodiment of the present invention, the shape of the relief portion formed on the bridge side and the shaft hole side is larger along the longitudinal direction of the bottom portion of the rotor slot than the shape of the other relief portion. Therefore, during high-speed rotation, the stress concentration due to centrifugal force at the corners of the rotor slot can be dispersed.As a result, the stress concentration due to the effect of the interference fit between the shaft hole and the rotation shaft is reduced, The strength of the rotor core can be maintained.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a permanent magnet type synchronous motor showing a first embodiment of the present invention.
FIGS. 2A and 2B show a permanent magnet type synchronous motor according to a second embodiment of the present invention, in which FIG. 2A is a cross-sectional view thereof, and FIG. 2B is an enlarged view illustrating a position of a clearance portion of a rotor slot of FIG. FIG.
FIG. 3 is a cross-sectional view of a permanent magnet type synchronous motor showing the first prior art.
FIGS. 4A and 4B are permanent magnet type synchronous motors showing a second prior art, in which FIG. 4A is a cross-sectional view thereof, and FIG. 4B is an enlarged view illustrating a position of a relief portion of a rotor slot of FIG. .
[Explanation of symbols]
1 Armature 2 Status lot 3 Winding 4 Rotating shaft 5 Rotor 51 Rotor core 51A Shaft hole 52 53 Rotor slots 52A, 52B, 52C, 52D, 53A, 53B, 53C, 53D Corners 52E, 53E Steps 52F, 53F Steps 52K, 52L, 52M, 52N, 53K, 53L, 53M, 53N: relief portion 54 salient pole portion 55 bridge 56, 57 thin portion 58, 59 punched holes 6A, 6B field permanent magnet

Claims (1)

A rotor core (51) made of laminated electromagnetic steel sheet;
A rotating shaft (4) fitted in the shaft hole (51A) of the rotor core (51);
Punch holes (58, 59) for preventing leakage magnetic flux provided in both wing parts of the rotor core (51);
A rectangular rotor slot (52, 53) provided so as to leave a central portion of the rotor core (51) between the punched holes (58, 59), and divided into left and right parts;
A rectangular field permanent magnet (6A, 6B) fitted in the rotor slot (52, 53);
Salient poles (54) formed on the upper surface of the field permanent magnet (6A, 6B);
A bridge (55) formed so as to connect the salient pole part (54) and the rotor core (51) between the rotor slots (52, 53);
The rotor slot (52, 53) includes a relief portion (52L, 52N, 53L, 53N) formed on one corner (52B, 52D, 53B, 53D) toward the shaft hole (51A), and the other In the rotor of a permanent magnet type synchronous motor provided with corner portions (52A, 52C, 53A, 53C) and relief portions (52K, 52M, 53K, 53M) formed toward the salient pole portion (54) side,
The relief portions (52L, 53L) formed on the bridge (55) side and the shaft hole (51A) side in the rotor slot (52, 53) are concentrated on the relief portions (52L, 53L) at one place. Outside the slot along the longitudinal direction of the bottom of the rotor slot (52, 53) compared to the shape of the other relief (52K, 52M, 52N, 53K, 53M, 53N) The rotor of the permanent magnet type synchronous motor is characterized by having a rectangular bulge that swells greatly .

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