Motor stator, method of manufacturing motor stator, and motor

Abstract

A stator and a method of manufacturing the same for facilitating a winding step of armature windings and reducing cogging torque. A segment part 121 radially having a plurality of teeth 121A and joined arcuately at one end is punched out from an oriented electromagnetic steel sheet 200, such segment parts 121 are circularly connected, the circularly connected segment parts 121 are stacked thereby forming a tooth part 120, armature winding 130 is wound from the other end of the tooth 121A, and the tooth part 120 is fitted into a circular yoke part 110 having a plurality of recesses 111 at the inner circumference and stacked in the axial direction of the motor.

Claims

1. A motor stator, comprising: a circular yoke part having a plurality of recesses at an inner circumference and stacked in an axial direction of a motor, a tooth part in which segment parts radially having a plurality of teeth contained at one end in the plurality of recesses and connected arcuately at the other end are joined circularly at a joint portion, and stacked in the axial direction of the motor, wherein the joint portion is at an end of each of the segment parts and at an inner circumferential surface of the tooth part, and armature windings wound from one end of the teeth, wherein each tooth of the plurality of teeth has an end portion provided into a corresponding one of the plurality of recesses at the inner cumference of the circular yoke part.

2. The motor stator according to claim 1, wherein the circularly connected segments are disposed being displaced and stacked such that seams formed in the axially adjacent circular segments are not aligned, wherein the joint portion includes one of the seams.

3. The motor stator according to claim 2, wherein the seams are distributed evenly with no localization over the segments when projected in the axial direction of the motor.

4. The motor stator according to claim 1 wherein the inner circumferential surface of the tooth part is joined circularly and a portion between each of the teeth is closed.

5. The motor stator according to claim 1, wherein the segment part comprises an oriented electromagnetic steel sheet in which the magnetic flux easy permeable rolling direction is directed to the longitudinal direction of the tooth part.

6. The motor stator according to claim 1, wherein the yoke part comprises a non-oriented electromagnetic steel sheet having magnetic properties excellent in average to all of directions.

7. A method of manufacturing a motor stator, comprising: a step of punching a segment part radially having a plurality of teeth and arcuately connected at one end from an oriented electromagnetic steel sheet, a step of circularly connecting the segment parts at a joint portion, wherein the joint portion is at an end of each of the segment parts and at an inner circumferential surface of the tooth part, a step of stacking the circularly- connected segment parts thereby forming a tooth part, a step of winding an armature winding from the other end of the tooth, and a step of fitting the tooth part into a circular yoke part having a plurality of recesses at the inner circumference and stacked in an axial direction of the motor; wherein each tooth of the plurality of teeth has an end portion provided into a corresponding one of the plurality of recesses at the inner circumference of the circular yoke part.

8. A motor, comprising: a rotor; and a stator in which teeth are wound with armature windings, including: a circular yoke part having a plurality of recesses at the inner circumference and stacked in an axial direction of the motor, a tooth part in which segment parts radially have a plurality of teeth contained at one end in the plurality of recesses and connected arcuately at the other end are joined circularly at a joint portion, and stacked in the axial direction of the motor, wherein the joint portion is at an end of each of the segment parts and at an inner circumferential surface of the tooth part, and an armature winding is wound from one end of the tooth, wherein each tooth of the plurality of teeth has an end portion provided into a corresponding one of the plurality of recesses at the inner circumference of the circular yoke part.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) [FIG. 1] is a cross sectional view showing the configuration of a stator according to the present embodiment.

(2) [FIG. 2] is a front elevational view showing details of a segment that configures a tooth part.

(3) [FIG. 3] is a front elevational view showing a state of joining segment parts and stacking tooth parts.

(4) [FIG. 4] is a cross sectional view showing a stacked tooth part.

(5) [FIG. 5] is a cross sectional view showing a yoke part.

(6) [FIG. 6] is a cross sectional view showing a stator and a rotor.

(7) [FIG. 7] is a cross sectional view showing the structure of an existent motor.

(8) [FIG. 8] is a detailed view showing armature windings inserted in slots.

DESCRIPTION OF EMBODIMENTS

(9) Preferred embodiments of the present invention are to be described in details with reference to the drawings.

(10) FIG. 1 is a cross sectional view showing the configuration of a stator according to the present embodiment.

(11) As shown in FIG. 1, a stator 100 includes a yoke part 110, a tooth part 120, and armature windings 130. This embodiment is an example comprising tooth 121A by the number of 48.

(12) The yoke part 110 is formed by punching a non-oriented electromagnetic steel sheet by a mold press so as to form an annular outer circumference and stacking same in the axial direction of the motor by using an adhesive, etc., in which the yoke part 110 has a plurality of recesses 111 (by the number of 48 in this embodiment) at the inner circumference of the yoke part 110.

(13) The tooth part 120 comprises a plurality of segments 121 (by the number of 16 in this embodiment) joined circularly. The segment 121 is formed by punching from an oriented electromagnetic steel sheet by using a mold press, and radially has a plurality of teeth 121A (by the number of 3 in this embodiment). One end of the tooth 121A is formed in symmetrical with the longitudinal direction of the recess 111 and the tooth 121A provided to the yoke part 110 and a portion at one end of the tooth 121A is in such a shape as contained in the recess 111. The other end of each of the teeth 121A is connected in a half arcuate shape to form “E”-shaped configuration.

(14) The segments 121 are joined circularly by way of a seam 122 to form a circular inner circumferential surface. Further, the segments 121 joined circularly are stacked in the axial direction of the motor by using an adhesive or the like.

(15) In the tooth part 120, each of a plurality of slots 121B is formed between each of the teeth 121A and armature winding 130 are wound in the slot 121B continuously in the axial direction of the motor.

(16) In the existent armature winding work, armature windings 13 had to be inserted through a narrow opening 14 as shown in FIG. 8. Further, since the torque generated in the motor is in proportion with the number of turns of the armature windings 13, the armature winding 13 had to be wound with no gap to the formed slot 12 in order to improve the torque.

(17) In this embodiment, each of the teeth 121A is arranged radially and the opening 121C of the slot 121B is formed spaciously. Thus, the winding work can be performed easily.

(18) After completion of the winding work, teeth 121A are inserted in the axial direction of the motor according to the recess 111 formed in the yoke part 110 to assemble the stator 100.

(19) FIG. 2 is a front elevational view showing details of a segment that configures the tooth part.

(20) As shown in FIG. 2, the segment 121 is formed by punching from an oriented electromagnetic steel sheet 200 by a mold press and radially has a plurality of teeth 121A (by the number of three in this embodiment).

(21) The oriented electromagnetic steel sheet is a steel sheet having an excellent magnetic property in the rolling direction in which magnetic flux tends to flow easily in the direction of an arrow 201.

(22) When a current flows in the motor, a magnetic field 123 is generated along the longitudinal direction of the radially provided tooth 121A. Since the tooth 121A is directed to the rolling direction of the electromagnetic steel sheet along the longitudinal direction of the tooth 121A, the magnetic field tends to flow easily and a large magnetic field can be taken. Further, loss of the magnetic field generated in the tooth part 120 can be decreased.

(23) Further, when compared with the step of punching out the tooth 121A in a divided shape one by one along the rolling direction of the oriented electromagnetic steel sheet and radially assembling the punched tooth 121A one by one, since segments 121 formed by joining three teeth 121A in advance are only have to be assembled into a circular shape in this embodiment, the working step of circularly arranging the tooth part 120 can be shortened remarkably.

(24) Further, since this embodiment comprises teeth 121A by the number of 48 in total, an angle of each tooth 121A is 7.5 degree. Ysince the angular difference between the rolling direction of the oriented electromagnetic steel sheet 200 and the tooth 121A is 7.5 degree, which is insignificant in the passing direction of the magnetic field in view of the characteristics, the tooth part 120 can be formed while decreasing the loss of the magnetic field generated in the tooth part 120.

(25) Further, if the number of slots is increased in order to improve the torque, the angle of the tooth 121A becomes small to approach the rolling direction. Accordingly, a motor increased in the number of slots for improving the torque can further take an advantageous effect of the oriented electromagnetic steel sheet.

(26) While the number of the segments 121 can be decreased by increasing the number of the teeth 121A that form the segments 121, if the number of the teeth 121A is increased, angular difference relative to the tooth 121A is increased more toward both ends of the segment 121 compared with the rolling direction of the oriented electromagnetic steel sheet. Accordingly, the amount of the teeth 121A provided in the segment 121 is desirably 2 to 3.

(27) FIG. 3 is a front elevational view showing the state of connecting the segment parts and stacking the tooth parts.

(28) FIG. 3(a) shows the state of joining the segments 121 by way of seams 122. The seams 122 are evenly distributed to the inner circumference of the tooth part 120, and they are arranged such that one of the seams 122 is at the uppermost end of the inner circumferential circle.

(29) FIG. 3(b) shows a state of circularly joining the segments 121 by way of the seams 122. The seams 122 are evenly distributed to the inner circumference of the tooth part 120, and arranged while being displaced by 7.5 degrees to the left, or 15 degree to the right from the state shown in FIG. 3(a).

(30) In the tooth part 120, segments 121 are stacked in the axial direction of the motor by using an adhesive or the like. It is preferred to stack them such that the FIG. 3(b) overlaps FIG. 3(a) upon stacking so as to avoid overlap of the seams 122. By stacking them with bonding while displacing the seams 122, the joined portions are dispersed to provide a firm structure.

(31) As has been described above, it is desirable to stack such that the seams 122 do not overlap on every repeating of stacking and disposing and stacking them such that the positions of the seams 122 are not localized entirely.

(32) FIG. 4 is a cross sectional view showing stacked tooth parts.

(33) As shown in FIG. 4, the tooth parts 120 stacked in the axial direction of the motor comprise a plurality of segments 121, and has radially comprising tooth 121A.

(34) When the stacking of the tooth parts 120 is completed, armature windings 130 are wound in the slot 121B formed between each of the tooth 121A. In the slots 121B, since the opening 121C is opened to the direction of the outer circumferential surface, work of winding the armature windings 130 is facilitated.

(35) Further, since the torque generated in the motor is in proportion to the number of turns of the armature windings 13, it is desired that the armature windings 130 are wound with no gaps in the slot 121B, Since the opening 121C is spacious, the armature winding 130 can be wound with no gaps in the slot 121B easily even by manual work. Thus, the torque generated in the motor can be improved.

(36) Further, the tooth 121A provided to each of the segments 121 is formed of the oriented electromagnetic steel sheet as has been described above and directed so that the rolling direction of the oriented electromagnetic steel sheet is along with a longitudinal direction of the tooth 121A. Since the segment 121 is arranged circularly by way of the seams 122, the rolling direction of the oriented electromagnetic steel sheet is directed to the longitudinal direction, that is, to the radial direction of each tooth 121A. Thus, when a current flows in the motor, since a magnetic field is generated along the radially provided tooth 121A, magnetic field loss can be decreased.

(37) FIG. 5 is a cross sectional view showing a yoke part.

(38) As shown in FIG. 5, a plurality of recesses 111 (by the number of 48 in this embodiment) are provided at the inner circumference of the yoke part 110.

(39) One end of the tooth 121A is formed in symmetrical with respect to the longitudinal direction of the recess 111 and the tooth 121A provided to the yoke part 110, and a portion at one end of the tooth 121A is shaped so as to be accommodated in the recess 111. The tooth part 120 for which winding of the armature winding 130 has been completed is inserted to the yoke part 110 such that the top end of the tooth 121A is aligned with the recess 111 provided to the yoke part 110. Thus, the tooth part 120 is fixed firmly to the yoke part 110.

(40) The yoke part 110 is a path of a magnetic flux generated in the tooth part 120 upon flowing of a current to the motor and the direction of the magnetic flux is not constant. Then, the yoke part 110 is prepared by using a non-oriented electromagnetic steel sheet, circularly punching the sheet so as to form a circular outer circumference of the sheet by a mold press and stacking the sheets in the axial direction of the motor by using an adhesive or the like.

(41) FIG. 6 is a cross sectional view showing a stator and a rotor.

(42) As shown in FIG. 6, a rotor 300 is provided to the inner circumferential side of the stator 100.

(43) In the rotor 300, a plurality of permanent magnets 320 (by the number of 8 in this embodiment) are fixed relative to the stator core 310 each at a predetermined distance along the axial direction of the motor.

(44) The thus configured rotor 300 is opposed by way of an air gap 400 to the inner circumferential surface of the stator 100.

(45) When a current flows to the armature windings 130, since the inner circumference of the stator 100 is closed, the magnetic field generated in the stator 100 does not concentrate to the tooth 121A but is dispersed to the inner circumferential surface of the stator 100. Thus, the difference of the magnetic attraction force caused upon movement of the rotor 300 is decreased thereby enabling to decrease the togging torque.

REFERENCE SIGNS LIST

(46) 10 yoke 11 tooth 12 slot 13 armature winding 14 opening 15 rotor 100 stator 110 yoke part 111 recess 120 tooth part 121 segment 121A tooth 121B slot 121C opening 122 seam 123 magnetic field 130 armature winding 200 oriented electromagnetic steel sheet 201 arrow 300 rotor 310 rotor core 320 permanent magnet 400 air gap