JPH0424784Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a motor with an improved stator core structure.

[Technical background of the invention]

For example, in a flat brushless motor used in a floppy disk drive device, the stator core has a plurality of teeth protruding from the outer periphery of an annular yoke, and stator coils are wound around the teeth to drive the stator. The stator core is mounted along a printed circuit board provided on the stator core, and the rotor is disposed with a gap in the radial direction on the outer circumferential side of the stator core. The stator core is usually constructed by laminating silicon steel plates.

[Problems with Background Art] However, in the above configuration, since the stator core is made of laminated steel plates, it cannot be bent and becomes flat. Therefore, in order to ensure an insulating distance between the stator coil wound around the teeth and the printed circuit board, the stator core must be attached to the printed circuit board via a spacer, which increases the number of parts and makes installation difficult. There is a problem that the structure becomes complicated. In addition, since the stator core is made of laminated steel plates, which suppresses the generation of eddy currents, ripples in the armature current, especially during high-speed rotation, immediately cause magnetic flux pulsations, which tends to cause torque unevenness. It was hot.

[Purpose of invention]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a motor that can simplify the mounting structure while suppressing an increase in the number of parts, and can prevent torque unevenness as much as possible.

[Summary of the idea]

The present invention allows the generation of eddy currents and suppresses the pulsation of magnetic flux by integrally forming the stator core with a magnetic material, and also includes a substantially annular structure having an L-shaped cross section on the inner circumferential side of the stator core. A mounting base is formed to enable direct mounting to the board, and the outer circumferential ends of a plurality of teeth with a constant thickness are provided to extend radially from the edge of the mounting base to the rotor axis. The feature is that the magnetic resistance is minimized by forming the rotor facing portion by bending it along the direction.

[Example of idea]

An embodiment in which the present invention is applied to a brushless motor for a floppy disk drive device will be described below with reference to FIGS. 1 and 2. 1 is a bearing 1a,
The bearing bracket 1a is installed therein, and 2 to 4 are printed circuit boards corresponding to a mounting plate, an insulating plate, and a board, respectively, which are fitted into the bearing bracket 1 in a mutually overlapping state. Reference numeral 5 denotes a stator core integrally formed from a magnetic material, and its inner circumferential side has a generally annular shape as a whole and a parallel portion that runs along the printed circuit board 4, and a stator core that extends in the axial direction from the outer circumferential side of this parallel portion. The mounting base 6 has an L-shaped cross section and has a rising portion integrally with the mounting base 6. It integrally has a plurality of plate-shaped teeth portions 7 of a constant thickness that protrude radially from the position. In addition, stator core 5
At the outer peripheral end of the teeth portion 7 corresponding to the outer peripheral side of
By bending the field permanent magnet 15 along the axial direction, which will be described later, the field permanent magnet 1 can be bent.
A rotor facing portion 8 is provided with a larger area of the surface facing the stator core 5, thereby minimizing the magnetic resistance between the field permanent magnet 15 and the stator core 5. . Reference numeral 9 denotes a stator coil wound around each teeth portion 7 of the stator core 5. In the stator core 5, the parallel portion along the printed circuit board 4 in the mounting base 6 is connected to the printed circuit board 4, the insulating plate 3, and the mounting plate 2.
It is also fixed to the flange portion 1b of the bearing bracket 1 with screws 10. In this fixed state, the mounting base 6 that is in contact with the printed circuit board 4 has an L-shaped cross section, and the teeth portions 7 radially protrude from above the bent portion of the mounting base 6 that extends in the axial direction. Therefore, the teeth portion 7 is in a floating state with respect to the printed circuit board 4, and a sufficient insulation distance between the stator coil 9 and the printed circuit board 4 is ensured. Next, in contrast to the stator 11 having the above structure, 12 is a rotor, and a flat cylindrical container-shaped rotor yoke 14 is screwed to a spindle 13 that is pivotally supported on a bearing 1a. It has an annular field permanent magnet 15 fixed to its inner surface. This rotor 12 is rotated by sequentially energizing each stator coil 9 according to its rotational position.

According to the above configuration, since the bent mounting base 6 having an L-shaped cross section is formed on the inner peripheral side of the stator core 5, the stator core 5 is placed between the stator coil 9 and the printed circuit board 4. It can be directly screwed to the printed circuit board 4 while ensuring a sufficient insulation distance. As a result, the spacer that was conventionally required between the stator core and the printed circuit board can be made unnecessary, and the number of parts can be reduced and the mounting structure can be simplified. Also,
Since the stator core 5 is made of an integral magnetic material, the eddy current generated in the stator core 5 when the stator coil 9 is energized is larger than that of a stator core made of a laminated steel plate. As is well known, this eddy current acts to suppress changes in the magnetic flux within the stator core 5, so even if the armature current flowing through the stator coil 9 contains ripples, the pulsation of the magnetic flux can be suppressed as much as possible, thereby reducing torque unevenness. can reduce the occurrence of Furthermore,
Since the rotor facing portion 8 is bent along the axial direction of the field permanent magnet 15 at the outer circumferential end of the tooth portion 7 of the stator core 5, the stator core 5
It is possible to secure a sufficient area facing the rotor 12, thereby suppressing magnetic resistance as much as possible and increasing the starting torque. Moreover, in the stator core 5, the teeth portion 7 is formed into a plate shape with a constant thickness that projects radially from the end edge of the mounting base 6, and the outer circumferential end of the teeth portion 7 is bent to form a portion facing the rotor. 8, it becomes possible to form the stator core 5 from a plate-shaped magnetic material, which can also be expected to improve manufacturability.

3 and 4 show different embodiments of the present invention, and the difference from the above embodiment is that a hole 16 (FIG. 3) or a notch 17 (FIG. 4) is provided in the rotor facing part of the stator core 5. It is at the point where it was formed. With this configuration, torque unevenness can be further reduced.

[Effect of idea]

As described above, the present invention includes a stator core that is integrally formed of a magnetic material, and a bent form that extends on the inner circumferential side of the stator core toward the substrate side of the stator and has an L-shaped cross section such that the tip is along the substrate. In addition to forming a mounting base, a plurality of plate-shaped teeth portions having a certain thickness are provided that extend radially from the edge of this mounting base, and the outer peripheral side ends of the teeth portions are aligned along the axial direction of the rotor. The stator core is characterized by having a bent rotor opposing portion, which simplifies the stator core mounting structure and reduces the number of parts, reducing manufacturing costs.
In addition, the eddy current generated in the stator core can be used to suppress the occurrence of torque unevenness, and it is also possible to increase the starting torque, which is an excellent effect.

[Brief explanation of the drawing]

1 and 2 show an embodiment of the present invention,
FIG. 1 is a partially cutaway overall view, FIG. 2 is a partial perspective view of a stator core, and FIGS. 3 and 4 are views corresponding to FIG. 2 showing different embodiments of the present invention. In the drawings, 4 is a printed circuit board (board), 5 is a stator core, 6 is a mounting base, 7 is a teeth portion, 8 is a rotor opposing portion, 9 is a stator coil, 11 is a stator, and 12 is a rotor.

Claims (1)

[Scope of utility model registration request] A stator core wound with a coil is attached to a stator substrate on the inner circumferential side, and a rotor is disposed on the outer circumferential side of the stator core with a gap in the radial direction, and the stator core has a cross-sectional shape of L. A substantially annular mounting base in the shape of a letter, a plurality of plate-shaped teeth portions having a constant thickness extending radially from the edge of the mounting base, and an outer circumferential end of the teeth portions extending along the axial direction of the rotor. What is claimed is: 1. A motor characterized in that the motor has a shape including a rotor facing portion bent in the shape of a rotor, and is integrally formed of a magnetic material.