JPH08214477A - Core assembly for small-sized motor - Google Patents

Abstract

PURPOSE: To provide a core assembly for small-sized motor which can reduce the magnetic directivity derived from the rolling direction even when the core assembly is made of a nonoriented electromagnetic rolled plate or oriented electromagnetic rolled plate. CONSTITUTION: A laminated core 12 formed by laminating a plurality of core pieces having the same magnetic directivity is provided between a pair of magnetism collecting cores having flanges 18 which are plastically worked so as to extend the flanges 18 in the axial direction. The magnetism collecting cores 11 and 13 and laminated core 12 are arranged so that their magnetic directivity can be shifted from each other.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a core assembly for a small motor. More specifically, the present invention relates to a core group of a small motor capable of reducing the magnetic directionality of the members constituting the core group based on the rolling direction of the rolled electromagnetic steel sheet.

[0002]

2. Description of the Related Art A rolled electromagnetic steel sheet used for a core assembly of a small motor is generally formed as a strip plate, and a core piece is punched by press working or the like. These strips are formed as strips having a predetermined thickness by rolling a silicon steel sheet material, annealing it, and repeating rolling and annealing several times. In the strip steel sheet used in the rolled state except for the final annealing step, the crystal orientation of the silicon steel sheet material is aligned with the rolling direction by rolling, and becomes a grain-oriented electrical steel sheet. In addition to this, there is a non-oriented electrical steel sheet in which after rolling, further treatment such as annealing is performed to eliminate the deviation of the crystal orientation. This non-oriented electrical steel sheet is considered to be preferable as a core material for a motor, but the commercially available non-oriented electrical steel sheet has magnetic orientation although it is less than the grain-oriented electrical steel sheet.

As described above, in both the grain-oriented electrical steel sheet and the non-oriented electrical steel sheet, the amount is different at the strip plate stage forming the core set, but it is considered to be due to the rolling direction and the non-rolling direction. Magnetic orientation appears due to possible differences in crystal form. That is, the iron loss and the magnetic flux density are different in the rolling direction and the non-rolling direction. Therefore, a magnetic property difference also appears in the molded product obtained by processing the electromagnetic steel sheet depending on the processing method, and a magnetic difference also occurs in the structure made of the molded product.

The core piece formed by punching an electromagnetic steel sheet by press working is also formed with magnetic directionality for the above-mentioned reason. That is, it is known that the magnetic flux easily passes through the punched product in the rolling direction or in the direction perpendicular to the rolling direction as compared with those in the other directions. In any case, the magnetic directivity also causes variations in quality of the core group of the small motor, and is not desirable for the core group of the small motor.

Therefore, conventionally, a non-oriented electrical steel sheet having a small magnetic orientation has been used as an electromagnetic steel sheet forming a core set, but the punched core pieces are rolled in order to disperse the magnetic orientation. The core pieces were laminated by rotating them by a certain angle with respect to the direction. Then, as the laminated core formed by laminating a plurality of core pieces, the laminated core is formed in a state in which magnetic directionality apparently does not occur. However, in the method of laminating the core pieces one by one in order to disperse the magnetic directivity, the laminating process is complicated and the manufacturing process is remarkably complicated.

On the other hand, in the core set in which the laminated core 2 is sandwiched between the magnetic flux collecting cores 1 and 3 having the flanges 8 whose ends are wide in the axial direction as shown in FIG. A method is adopted in which core pieces forming the laminated core 2 are continuously punched from a rolled steel plate made of a strip material by a press or the like and laminated in the same direction. This process is automated, and the laminated cores 2 can be efficiently mass-produced by stacking core pieces whose rolling directions are constant as they are. Then, a pair of magnetic flux collecting cores 1 and 3 are stacked and crimped on the laminated core 2 so that the laminated core 2 is sandwiched.

FIG. 2 is a diagram for explaining the structure and magnetic directivity of the core set 4 of this conventional motor. The core group 4 of this small-sized motor has a three-pole structure in which the directions of the ribs 6 of the laminated core 2 form an angle of 120 degrees with each other. In this structure, the core set 4 is formed by combining the magnetic flux collecting cores 1 and 3 and the laminated core 2. The strips of the magnetic flux collecting cores 1 and 3 and the laminated core 2 are punched out using a strip of an electromagnetic steel sheet which is as non-directional as possible, and the laminated pieces are laminated as they are according to the rolling direction. The shaft 7 is passed through a shaft through hole 9 formed in the center of the magnetic flux collecting cores 1 and 3 and the laminated core 2,
At the same time, the ribs 5 of the pair of magnetic flux collecting cores 1 and 3 are aligned with the ribs 6 of the laminated core to form a rotor set. Reference numeral 8 is a flange provided on the magnetic flux collecting cores 1 and 3. Therefore, the laminated core 2, which is a laminate of core pieces, also has a constant rolling direction. This is combined with the magnetic flux collecting cores 1 and 3 without particularly considering the magnetic directionality thereof.

[0008]

As described above, the core group of the motor having the conventional magnetism collecting cores 1 and 3 is the magnetism collecting core 1,
3 and the laminated core 2 are combined without considering the magnetic directionality of the laminated core 2, the pair of magnetism collecting cores 1, 3
Those in which the rolling direction of 1 and the rolling direction of the laminated core 2 are aligned or not aligned are assembled as the core set 4. However, in the magnetic flux collecting cores 1 and 3, since the flange 8 that is the end face facing the motor magnet is formed wide in the axial direction, the amount of magnetic flux passing through this end face and the amount of magnetic flux passing through the end face of the laminated core 2 are different. The situation is almost unchanged. Therefore, the influence of the magnetic directionality of the magnetic flux collecting cores 1 and 3 cannot be ignored. Further, the magnetic flux collecting cores 1 and 3
Is bent when forming the flange 8,
The strain at the time of processing also largely changes in the rolling direction and the direction not so, and the difference in the strain greatly affects the passing amount of the magnetic flux. Therefore, the magnetic flux collecting core 1,
In the conventional assembly of 3 and the laminated core, the amount of magnetic flux passing through the core set 4 via the ribs 5 and 6 is not constant, and changes in motor characteristics, particularly cogging changes, torque ripple, This is a factor that makes it impossible to maintain constant characteristics such as rotational stability and vibration.

Therefore, the present invention has been made in order to solve the problems of the prior art as described above, and the flanges of the end faces of the pair of magnetism collecting cores opposed to the motor magnets are arranged so as to sandwich the laminated core. Focusing on the fact that the magnetic flux density passing through is almost the same as the magnetic flux density passing through the end surface of the laminated core, even if the laminated core has a magnetic directionality, by changing the rolling direction of the magnetism collecting core from the rolling direction of the laminated core, The magnetic directionality is canceled out as a core set, and not only the core set made of non-oriented electromagnetic rolled steel sheet, but also the core set made of grain oriented electromagnetic rolled steel sheet, the magnetic directionality based on the rolling direction is set. An object of the present invention is to provide a small motor that can be reduced. The small motor using the core assembly having this configuration has less change in cogging, and can have constant characteristics such as noise, torque ripple, rotation stability, and vibration.

[0010]

Therefore, in order to solve the above-mentioned problems, the invention according to claim 1 has a structure in which, between a pair of magnetism collecting cores having a flange plastically formed so as to extend in the axial direction, In a core group of a small motor formed by stacking a plurality of core pieces that have the same magnetic direction, the magnetic direction of each of the pair of magnetic flux collecting cores and the laminated core is They are arranged offset from each other. Also,
The invention according to claim 2 is the core set of the small motor according to claim 1, wherein the core set includes a first magnetism collecting core, a second magnetism collecting core, each having P salient poles. They are laminated, and they are arranged with their magnetic directions shifted by 360 ° / P.

As a result, the amount of magnetic flux passing through the flange of the end faces facing the motor magnet of the pair of magnetic flux collecting cores configured to sandwich the laminated core, that is, the magnetic flux density is the same as the magnetic flux density passing through the end faces of the laminated core. Since there is almost no change, even if the laminated core has magnetic directionality, by changing the rolling direction of the magnetism collecting core to the rolling direction of the laminated core, the magnetic directionality of the core set can be offset. In addition, the change in the amount of magnetic flux passing due to the strain that occurs when forming the flange by bending can be offset by the entire core set.

[0012]

1 is a view showing an embodiment of a core group of a small motor of the present invention, which is contrasted with FIG. The same description as that of the conventional example will be omitted.

The first magnetism collecting core 11 and the second magnetism collecting core 13 are ribs 1 facing a motor magnet (not shown).
The end face of 5 is formed as a flange 18. Moreover, the height h of the edge of the flange 18 is configured to be about half of the laminated thickness m of the laminated core 12. Therefore, even if the laminated cores 12 are sandwiched by one sheet each, the first magnetic core becomes a pair of magnetic flux collecting cores.
Since the sum 2h of the heights of the flanges 18 of the magnetic flux collecting core 11 and the second magnetic flux collecting core 13 is substantially the same as the laminated thickness m of the laminated core 12, the first magnetic flux collecting core 11 and the second magnetic flux collecting core 11 The magnetic flux collecting core 13 is affected by the magnetic characteristics that are substantially the same as those of the laminated core 12 in which a plurality of core pieces are laminated.

As shown in the combination of FIG. 1a and FIG. 1b, the present invention provides a first roll formed in the same rolling direction.
In assembling the magnetic flux collecting core 11, the laminated core 12, and the second magnetic flux collecting core 13, the cores are assembled so that the rolling directions of the respective cores do not match. At the time of assembly, if the difference between the rolling directions is 120 degrees, the balance of the magnetic directionality is improved, which is preferable in terms of making the amount of magnetic flux uniform.

Further, as shown in the combination of FIGS. 1c and 1d, the first magnetic flux collecting core 11 and the second magnetic flux collecting core 13 are formed.
Direction with respect to ribs 15 of ribs and ribs 16 of laminated core 12
Change the rolling direction with respect to 90 °. Then, the first and second magnetism collecting cores 11 and 13 and the laminated core 12 having different rolling directions are assembled while avoiding positions where the respective rolling directions change by 90 °. This is because the rolling direction is 90
This is because if the assembly is allowed at a position changing to .degree., Only one set of the three rib portions may easily pass the magnetic flux.

In this example, the influence of the magnetic characteristics of the first magnetism collecting core 11, the laminated core 12, and the second magnetism collecting core 13 on the motor is divided into three parts on average, and these three parts 1
By offsetting the magnetic orientations of 1, 12, and 13 from each other, the influence of magnetism due to the rolling direction can be eliminated.

Further, when the first and second magnetic flux collecting cores 11 and 13 are manufactured, a bending process is performed to form the flange 18 on the end face facing the motor magnet (not shown). The rolling direction and the non-rolling direction are different. The difference in strain has a large effect on the passage amount of the magnetic flux, but this can also eliminate the influence of the magnetic directionality by shifting the magnetic directionality of the three components 11, 12, 13 from each other.

In the above embodiments, the case of three salient poles has been described as an example, but the present invention can be applied to other plural salient poles. In particular, when the number of salient poles is P, the first magnetic flux collecting core 11, the laminated core 12, and the second magnetic flux collecting core 13 are set to 3
By shifting the magnetic direction by 60 ° / P, the rolling direction can be set to a predetermined direction with the salient pole as a reference, and when assembling so that the magnetic direction is different, the assembling is efficient. Can be done well.

The core set according to the present invention can be applied not only to a core set formed from a grain-oriented electrical steel sheet, but also to a core set formed from a non-oriented electrical steel sheet. This is because the non-oriented electrical steel sheet also has magnetic directivity, although it is less than the grain-oriented electrical steel sheet. Further, the core set for the rotor or the core set for the stator can be used for any of the brushed and brushless motors.

[0020]

As described above, according to the first aspect of the present invention, the amount of magnetic flux flowing in each rib of the core set is made uniform, so that the magnetic balance is improved and the characteristics of the small motor are stabilized. The motor has less variation. Therefore, the reliability of the motor is improved. Moreover, the structure is much simpler than the conventional method in which the core pieces of the laminated core are slightly shifted and laminated, and the assembly efficiency and mass productivity are not impaired.

According to the second aspect of the invention, since the magnetic directionality is shifted by the angle of the salient pole, the first magnetic flux collecting core,
Each of the second magnetic flux collecting core and the laminated core can be rolled with reference to a specific salient pole. That is, at the time of assembly, the specific salient pole can be shifted and the magnetic salient pole can be easily shifted by superimposing it on the adjacent salient pole. Therefore, manufacturing and assembling can be performed extremely easily.

[Brief description of drawings]

FIG. 1 is an example of a core set of the present invention, and is a diagram for explaining magnetic directionality in this configuration.

FIG. 2 is an example of a core set having a three-pole structure in which the rib directions of conventional core pieces form an angle of 120 degrees with each other, and is a diagram for explaining the magnetic directivity in this configuration.

[Explanation of symbols]

 11 1st magnetism collecting core 12 Laminated core 13 2nd magnetism collecting core 15 Rib 16 Rib 17 Shaft 18 Flange 19 Shaft through hole

Claims (2)

[Claims] 1. A narrow laminated core formed by laminating a plurality of core pieces having the same magnetic directionality between a pair of magnetic flux collecting cores each having a flange plastically processed to extend in the axial direction. A core group of a small motor, wherein the pair of magnetism collecting cores and the laminated core are arranged such that their magnetic directions are offset from each other. 2. The core group of the small motor according to claim 1, wherein the core group has P salient poles.
The magnetic motor core group, the second magnetic core core, and the laminated core, which are arranged such that their magnetic directions are shifted from each other by 360 ° / P.