JPH0145260Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a step motor, and provides a step motor equipped with a disc-shaped rotor that can be made smaller by eliminating a coil bobbin and can increase the output torque of the motor. The purpose is to provide.

In general, step motors are broadly classified into so-called cylindrical step motors and flat step motors. A cylindrical step motor has a rotor having a cylindrical shape, a plurality of magnetic poles are magnetized and formed on the outer peripheral surface of the rotor, and a plurality of magnetic pole pieces are provided on the magnetic poles at a distance and facing each other. On the other hand, in a flat step motor, the rotor is disc-shaped, and a plurality of substantially fan-shaped magnetic poles are magnetized on the surface perpendicular to the axis with different polarities alternately in the circumferential direction. The structure includes an inner stator having a plurality of inner pole pieces and an outer stator having a plurality of outer pole pieces.

In this conventional flat step motor, a coil bobbin wound with a coil is fitted into a yoke. An outer stator is attached to the outer stator, and an inner stator is attached to the end of the inner circumferential wall, and both ends are magnetized with different polarities by a coil.

Generally, a coil bobbin is a member used to facilitate the construction of a coil, but once the coil is wound, it serves no other purpose other than to prevent the coil from losing its shape. Therefore, when the coil bobbin is assembled to the yoke, it occupies that much space, which has the disadvantage of interfering with the compact configuration of the step motor, and also has the disadvantage that the assembly work is complicated. It was hot. Furthermore, since the inner circumferential wall of the yoke and the coil are isolated from each other by the thick portion of the coil bobbin, the winding efficiency is low and it is difficult to increase the magnetic flux density and output torque. Therefore, if the number of turns of the coil is increased in order to increase this output torque, the coil itself will inevitably become larger.
Conflicting problems remain with respect to both the miniaturization of the step motor and the improvement of output torque.

The present invention eliminates the above-mentioned drawbacks and problems, and one embodiment thereof will be described below with reference to the drawings.

FIG. 1 is a longitudinal cross-sectional view of one embodiment of a step motor according to the present invention, and FIG. 2 is a view taken along a plane including the line ``--'' in FIG.

Reference numeral 2 denotes a disk-shaped rotor having a shaft 4 attached to a bush 3, and a plurality of approximately fan-shaped sections obtained by dividing a plane perpendicular to the axis radially at approximately equal angles have polarities alternately different in the circumferential direction. The magnetic poles are magnetized in the axial direction. As shown in FIG. 2, at positions spaced apart from and opposing the axis of the rotor 2, there are inner stators 5, 5' having a plurality of inner magnetic pole pieces 5a, 5a' and a plurality of outer magnetic pole pieces 6a, 6a. Outer stators 6, 6' having radial angles 6 and 6' are provided on both left and right sides.

The inner stator 5, 5' is the cylinder body 8 of the yoke 7, 7',
It is attached at the ends 8a, 8a' of 8',
The outer stators 6, 6' are mounted at the ends 9a, 9a' of the flanges 9, 9' of the yokes 7, 7', and both outer stators 6, 6' are held by a substantially cylindrical spacer 10. ing. On the other hand, the bent portions 7a, 7a' of the yokes 7, 7' are mounted on stepped portions formed on the bearings 11, 11'. Coils 12, 12' are directly wound around the cylinders 8, 8' of the yokes 7, 7'. The coils 12, 12' are wound around the cylinders 8, 8' of the yokes 7, 7', and the flanges 9, 9' abut on one end surface of the coils 12, 12', and on the other end surface. The inner magnetic pole pieces 5a, 5a' of the inner stators 5, 5' and the outer magnetic pole pieces 6a, 6a' of the outer stators 6, 6' are in contact with each other to prevent them from deforming.

As described above, this step motor 1 has a rotor 2
2 configured symmetrically with respect to the center of the plane perpendicular to the axis of
It is a phase motor. Therefore, only the left phase will be described below, and the description of the right phase having the same configuration as this phase will be omitted.

Both ends 8a and 9a of the yoke 7, around which the coil 12 is directly wound, are magnetized with different polarities, and the inner magnetic pole piece 5a of the inner stator 5 is attached to the end 8a, and the outer stator is attached to the end 9a. It is magnetized to a different polarity from the outer magnetic pole piece 6a of No. 6, and as is well known, the stepping operation of the rotor 2 is performed.

As mentioned above, the yoke 7, which serves as a core for guiding magnetic flux, is not fitted with a coil bobbin as in the conventional case, but extends in the axial direction so that the coil 12 is directly wound thereon. and a cylinder 8 to which the inner stator 5 is attached at the end 8a;
The other end, that is, the bent portion 7a, is provided in a plane perpendicular to the axis, and the outer stator 6 is attached at the end 9a.

Hereinafter, a method of winding the coil 12 around this yoke 7 will be explained.

A substantially disc-shaped printed circuit board 15 as shown in FIG. 3 is fitted to the end of the cylinder 8, facing away from the collars 9,'. A pair of notches 16, 16' are provided at the peripheral end of this printed circuit board 15, and copper foils 18, 18' are formed from the protruding piece 17 to the locations of both notches 16, 16'. After winding, the terminal at the start of winding and the terminal at the end of winding are connected to the copper foil portions of both cutouts 16, 16' by soldering, spot welding, or the like. Therefore, by using this printed circuit board 15, winding of the coil can be easily performed and terminal connection processing after winding can be easily performed.

Since the yoke wound with the coil in this manner is attached to the step motor 1, the conventionally used coil bobbin can be eliminated, the step motor 1 can be made compact, and the coil can be wound by the thickness of the coil bobbin. Since the winding can be rotated, the winding efficiency is increased, and the output torque of the motor can be improved compared to the conventional motor.

As described above, the step motor according to the present invention includes a rotor whose polarity is alternately changed in the circumferential direction and magnetized in the axial direction, and a plurality of inner magnetic pole pieces spaced apart and opposed to each other in a plane perpendicular to the axis of the rotor. an outer stator having a stator and a plurality of outer magnetic pole pieces; and a yoke to which the inner stator and outer stator are attached at first and second ends magnetized to different polarities by a coil. In the step motor, the yoke is arranged in a cylindrical body extending in the axial direction and having the first end, and the other end of the cylindrical body facing the first end in a plane perpendicular to the axis. a flange integrally formed with the cylindrical body and having the second end; the first end of the cylindrical body is spaced apart from and opposed to the flange; A printed circuit board having a notch and copper foil connecting both ends of the yoke is fitted, and the coil is wound directly between the second end of the yoke and the printed circuit board. Since the coil bobbin can be eliminated, the step motor can be made smaller, but the number of parts and assembly man-hours can be reduced, making it possible to provide a low-cost step motor.In addition, the coil can be installed in the space corresponding to the thick part of the coil bobbin. Since it can be wound, the winding efficiency is improved, which makes it possible to realize miniaturization, improve the output torque of the motor, improve response characteristics and starting characteristics, and furthermore, the inner stator can be When the coil is wound by attaching it to the yoke, it has the advantage that the labor of assembling work can be reduced and the terminal connection process after winding becomes easy.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional view of one embodiment of the step motor according to the present invention, Fig. 2 is a view taken along a plane including the - line in Fig. 1, and Fig. 3A is a yoke in this embodiment. A diagram showing an example of winding a coil, and FIG. 3B is a diagram showing a printed circuit board used therein. 1...Step motor, 2...Rotor, 3...
Bush, 4... shaft, 5, 5'... inner stator,
5a, 5a'...Inner magnetic pole piece, 6,6'...Outer stator, 6a, 6a'...Outer magnetic pole piece, 7,7'...
Yoke, 7a, 7a'...bent portion, 8, 8'...tube, 8a, 8a'...end, 9, 9'...flange, 9
a, 9a'... end, 10... spacer, 11, 1
1'... Bearing, 12, 12'... Coil.

Claims (1)

[Scope of utility model registration request] A rotor having alternately different polarities in the circumferential direction and magnetized in the axial direction, an inner stator having a plurality of inner pole pieces spaced apart from each other in a plane perpendicular to the axis of the rotor, and an outer stator having a plurality of outer pole pieces. In a step motor comprising a stator and a yoke having the inner stator and the outer stator attached at first and second ends magnetized to different polarities by coils, the yoke is attached to a shaft. A cylindrical body extending in the direction and having the first end; and the other end of the cylindrical body opposite to the first end integrally formed in a plane perpendicular to the axis and having the second end. a flange, a notch and a copper foil are provided at the first end of the cylindrical body so as to be spaced apart from and opposite to the flange, and at the circumferential end to connect both ends of the winding start and winding end of the coil. A step motor, in which a printed circuit board is fitted, and the coil is wound directly between the second end of the yoke and the printed circuit board.