JP2004112951A - Rotor for brushless dc motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rotor, wherein, even if there is a difference in the coefficients of linear expansion between molding resin and a shaft, a backlash will not be produced between the shaft and a support. <P>SOLUTION: The rotor comprises a laminated punched plate obtained by punching a magnetic thin plate and laminating the punched pieces; the shaft formed by subjecting a drawn material to machining, such as turning; and the support which is molded from molding resin and holds the laminated punched plate on the shaft with resin interposed inbetween. A helical groove is formed in the portion of the shaft which is mated with the support. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a rotor for a brushless DC motor.
[0002]
[Prior art]
Conventionally, as a method of manufacturing a rotor, a method of inserting a permanent magnet or a shaft into a resin mold and performing injection molding has been generally used. (Patent Document 1)
[0003]
[Patent Document 1]
JP 2001-178040 A
Since it is similar to the above-mentioned publication, a conventional example performed by our company will be described with reference to FIGS. 8, 9 and 10. FIG. FIG. 8 is a side view of a conventional shaft, FIG. 9 is a cross-sectional view of a serrated portion of FIG. 8, and FIG. 10 shows a rotor using a conventional shaft.
[0005]
The rotor 50 of the conventional brushless DC motor includes a laminated punched plate 52 in which magnetic punched plates are stacked, a permanent magnet 56 inserted in a slot of the punched plate 52, and a rod-shaped shaft 53 having an output unit. , And a support 54 made of a mold resin, which is interposed between the shaft 53 and the laminated blank 52 and holds the two.
[0006]
A serration 55 is applied to an outer peripheral portion of the shaft 53 at an engagement portion with the mold resin support 54 to prevent the support 54 from rotating in the circumferential direction. A groove 57 is formed in the circumferential direction of the outer periphery of the serrated portion 55 as a countermeasure for preventing it from coming off in the axial direction.
[0007]
However, due to the difference in the linear expansion coefficient between the mold resin support 54 and the steel shaft 53 and insufficient control of the molding conditions at the time of molding, the molding resin portion and the shaft 53 are not connected to each other. Since slight backlash sometimes occurred, frequent mold maintenance was required, and it was necessary to check the backlash of the completed rotor.
[0008]
Further, when the serration 55 takes a long time to be processed, and when the looseness of the rotor is found after being incorporated in the motor, the rotor is disassembled and discarded. In addition, it was difficult to separate and discard the rotor. The mold of the support 54 holding the shaft 53 and the laminated blank 52 is formed by insert molding.
[0009]
[Problems to be solved by the invention]
The present invention has been made in view of such circumstances, and even if there is a difference in the coefficient of linear expansion between the mold resin and the shaft, insufficient maintenance of the resin mold, dispersion of the molding conditions, etc. It is an object of the present invention to provide a rotor that does not cause backlash between the rotor and the rotor, and to provide a rotor that can be easily assembled and disassembled, shortens disassembly time, and enables sorting and disposal.
[0010]
[Means for Solving the Problems]
Claim 1 of the present invention is a rotor for a brushless DC motor in which different magnetic poles are alternately magnetized along a circumferential direction, wherein the rotor is formed by punching and laminating a magnetic thin plate, and a drawn material. A shaft formed by performing machining such as turning, and a support made of molding resin holding the laminated blanked plate on the shaft with a resin interposed therebetween, and a support for the shaft. By forming the gusset-shaped groove in the engaging portion, play is prevented from occurring between the shaft and the support, thereby solving the problem.
[0011]
The rotor according to claim 2 of the present invention, a shaft formed by performing machining such as turning a drawn material having a polygonal outer shape, a laminated punched sheet obtained by punching and laminating a magnetic thin plate, It comprises a support formed by molding a resin, and a substantially disk-shaped contact plate using a non-magnetic material. A plate is inserted, the support is attached to a polygonal portion formed on the outer diameter portion of the shaft, and the contact plate is engaged with the support inserted into the shaft and fastened by a fixing member, The shaft and the laminated punched plate are held by the support, and a rotor that does not cause backlash between the shaft and the support is obtained. I have.
[0012]
The rotor according to claim 3 of the present invention includes a shaft formed by performing machining such as turning a drawn material having a polygonal outer shape, a laminated punched sheet obtained by punching and laminating a magnetic thin plate, and a resin. It consists of a support formed by molding, and a disk-shaped abutting plate using a non-magnetic material. The support has a plurality of permanent magnets mounted thereon or the laminated punched plate to be mounted is inserted. Further, the support is mounted on the polygonal portion of the shaft, and the abutment plate and the holding plate are disposed on both side surfaces of the support, and the two plates are connected by a fastening member. By fastening in the above, the rotor supporting the support on the shaft, the backlash does not occur between the shaft and the support, furthermore, the assembly and disassembly are easy and the disassembly time can be shortened to solve the problem. ing.
[0013]
In the rotor according to a fourth aspect of the present invention, the support is switched from a resin-made one to a die-cast one, and this configuration has the same effect as that of the third aspect and solves the problem.
[0014]
The rotator according to claim 5 of the present invention is used for a direct drive motor for a washing machine in which a rotating shaft of a motor is directly connected to a stirring body of the washing machine and rotated.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 is a side sectional view of a rotor according to an embodiment of the present invention, FIG. 2 is a view of FIG. 1 as viewed from the front, FIG. 3 is a side view of a shaft according to one embodiment of the present invention. Description will be made based on these drawings.
[0016]
(First embodiment)
First Embodiment A first embodiment of the present invention will be described with reference to FIGS. The rotor 1 of the brushless DC motor includes a laminated punched plate 2 in which thin plates made of a magnetic material are stacked, a permanent magnet 6 inserted into a slot (punched hole) formed in the punched plate 2, and one end having an output. It is composed of a rod-shaped shaft 3 serving as a shaft, and a support 4 made of a molded resin that holds the laminated blank 2 via a resin on the shaft 3. The rotor 1 is formed by insert molding in which the shaft 3 and the laminated blank 2 are set in a mold and then molded.
[0017]
Note that the insert molding is to insert the shaft 3 and the laminated blank 2 into a mold and then inject a mold resin to integrally mold the mold. Further, a boss-shaped groove 5 is formed at the joint of the outer periphery of the shaft 3 with the mold resin to prevent rotation.
[0018]
In this manner, a groove 5 having a helical shape (a state in which a groove is formed by being inclined) is formed on the outer peripheral portion of the shaft, and thereafter, molding is performed, whereby the shaft 3 made of a steel material and the support 4 made of a molding resin are formed. Even if there is a difference in the coefficient of linear expansion between them, and even if the management of the mold and the molding conditions of the mold are somewhat insufficient, it is possible to prevent the occurrence of play in the radial and axial directions. Became.
[0019]
In addition, by processing the shaft into a helical shape, it is possible to prevent rattling in both the circumferential direction and the axial direction with only one process of processing the shaft into a helical shape. Became. Therefore, the processing time of the shaft is shorter than before, and the shaft can be manufactured at low cost. A motor having a rotor having such a configuration is particularly effective when used for a direct drive type motor for a washing machine that requires a high torque strength.
[0020]
(Second embodiment)
Second Embodiment A second embodiment of the present invention will be described with reference to FIGS. FIG. 4 is a side view of the shaft of the second embodiment, FIG. 5 is a side sectional view of the rotor of the second embodiment, and FIG. 6 is a front view of FIG.
[0021]
The rotor 11 includes a shaft 13 formed by machining a drawn material having a polygonal shape (a quadrangle in the embodiment), such as turning, and a laminated punched plate 12 formed by punching and laminating thin plates. And a contact plate 15 made of a non-magnetic material. A square hole for inserting the shaft 13 is formed in the center of the support 14, and the stacked punched plates 12 can be mounted on the outer periphery of the support 14. . Further, a plurality of slots are formed in the vicinity of the outer periphery of the stacked laminated blanks, and the permanent magnets 16 are mounted in the slots.
[0022]
Next, the assembly of the rotor in such a configuration of each component will be described. First, the stacked laminated plates 12 are mounted on the resin support 14. Next, the permanent magnet 16 is inserted into the slot of the laminated blank 12. Next, a portion where the outer periphery of the shaft 13 has a quadrangular shape is inserted into the square hole of the resin support 14. After the contact plate 15 is inserted into the shaft 13 from the opposite side, the support plate 14 is fixed to the shaft 13 by fastening the contact plate 15 and the support 14 with screws 28. This eliminates the risk of rotation between the shaft 13 and the support 14. The strength of the screw portion can be maintained by burying a metal buried metal. The mounting of the permanent magnet 16 on the laminated blank 12 may be performed in any process before the contact plate 15 is inserted into the shaft 13. The support 14 may be made of a die-cast material instead of a resin material.
[0023]
In this way, by using the polygonal portion of the polygonal drawn material to prevent rotation, the number of processing steps of the shaft can be reduced, and thus the cost of the shaft can be reduced.
[0024]
(Third embodiment)
A third embodiment of the present invention will be described with reference to FIG. FIG. 7 is a side sectional view of the rotor of the third embodiment.
[0025]
The rotor 21 includes a shaft 23 formed by machining a drawn material having an outer shape of a polygon (a quadrangle in FIG. 7) such as turning, a laminated punched plate 22 formed of a laminated punched plate, It comprises a support 24 (laminated plate + magnet) formed by a resin mold and a contact plate 25 made of a non-magnetic material. The laminated plate 22 and a plurality of permanent magnets 26 are mounted on the support 24, and the support 24 is inserted into a polygonal portion 27 formed on the outer periphery of the shaft 23. ing.
[0026]
The contact plate 25 and the holding plate 29 are disposed on both side surfaces of the support 24, and the contact plate 25 and the holding plate 29 are fastened to each other by the fastening member 28. The support 24 is secured. By forming the support 14 as shown in FIG. 5, the pressing plate 29 can be omitted, and the shaft can be held by fastening the support 14 and the contact plate 15 with screws.
[0027]
In addition, the support 14 can be used by directly threading the support 14 by using a die-cast support. When a mold resin is used for the support 14, the strength can be maintained by using an embedded metal for the screw portion. The rotating shaft of the brushless DC motor using the rotor can be directly connected to the agitator of the washing machine to be used as a direct drive motor for the washing machine.
[0028]
Such a configuration is effective for a direct drive motor for a washing machine or the like that requires particularly high strength between the shaft 3 and the mold resin support 4.
[0029]
【The invention's effect】
By applying helical teeth to the shaft of the rotor of the present invention, it is possible to prevent rattling in the circumferential direction and axial direction between the shaft and the support, and no groove is required for retaining the shaft. It becomes cheap.
[0030]
Further, by using a polygonal drawn material for the shaft and inserting a support made of resin or die-cast into the polygonal portion of the shaft, it is possible to prevent rattling in the circumferential direction and the axial direction. Can be. Further, assembly and disassembly of the rotor are facilitated. Therefore, when discarding, it is possible to separate and discard, and the parts can be recycled.
[Brief description of the drawings]
FIG. 1 is a side sectional view of a rotor according to an embodiment of the present invention.
FIG. 2 is a front view of FIG. 1;
FIG. 3 is a side view of a shaft according to one embodiment of the present invention.
FIG. 4 is a side view of a shaft according to a second embodiment.
FIG. 5 is a side sectional view of a rotor according to a second embodiment.
FIG. 6 is a front view of FIG. 5;
FIG. 7 is a side sectional view of a rotor according to a third embodiment.
FIG. 8 is a side view of a conventional shaft.
FIG. 9 is a cross-sectional view of the serrated portion in FIG. 8;
FIG. 10 shows a rotor using a conventional shaft.
[Explanation of symbols]
1.11.21. Rotor 2.12.22. 3.13.23. Shaft 4.14.24. Support 5. Vessel-shaped groove 6.16.26.56. Permanent magnet 15. Contact plate 17.27. Polygon part 28. Screw 29. Push plate 55. Serration 57. groove

Claims (5)

In a brushless DC motor rotor in which different magnetic poles are alternately magnetized along the circumferential direction,
The rotor,
A laminated punched sheet made by punching and laminating a magnetic thin plate,
A shaft formed by performing machining such as turning on the drawn material,
A support made of molding resin holding the laminated punched plate on the shaft with a resin interposed therebetween,
A rotor for a brushless DC motor, wherein a helical groove is formed in a support engagement portion of the shaft. In a brushless DC motor rotor in which different magnetic poles are alternately magnetized along the circumferential direction,
The rotor,
A shaft formed by performing machining such as turning on a drawn material whose external shape is polygonal,
A laminated punched sheet made by punching and laminating a magnetic thin plate,
A support formed by molding a resin,
It consists of a substantially disc-shaped abutting plate made of non-magnetic material,
The laminated punched plate to which a plurality of permanent magnets are mounted or mounted is inserted into the support,
The support is attached to a polygon formed on the outer diameter of the shaft,
A rotor for a brushless DC motor, wherein the shaft and the laminated punched plate are held by the support by engaging the contact plate with a support inserted into the shaft and fastening with a fixing member. . In a brushless DC motor rotor in which different magnetic poles are alternately magnetized along the circumferential direction,
The rotor,
A shaft formed by performing machining such as turning on a drawn material whose external shape is polygonal,
A laminated punched sheet made by punching and laminating a magnetic thin plate,
A support formed by molding a resin,
It consists of a disk-shaped contact plate using a non-magnetic material,
The laminated punched plate to which a plurality of permanent magnets are mounted or mounted is inserted into the support,
Further, the support is attached to the polygonal portion of the shaft,
The support plate is supported on the shaft by arranging the contact plate and the holding plate on both side surfaces of the support member and fastening the two plates with a fastening member. Rotor for brushless DC motor. 4. The rotor for a brushless DC motor according to claim 1, wherein said support is made of die-cast. 5. The rotor for a brushless DC motor according to claim 1, wherein the rotating shaft of the motor is directly connected to the agitator of the washing machine to be used as a direct drive motor for the washing machine.

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