JPH0640730B2 - Small electric motor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a skeleton type small electric motor, and more particularly to D
By making the C brushless, the efficiency of the electric motor is improved and the rotation speed control is facilitated.

(B) Prior Art Generally, a small skeleton type electric motor having a stator core and a stator winding, for example, a cornering electric motor as described in Japanese Examined Patent Publication No. 57-16575, is small and has a simple structure and is easy to manufacture. Since it was easy, it was generally used as an inexpensive electric motor. However, in such a cornering motor, a cornering coil is provided on the stator core in addition to the stator winding to form a rotating magnetic field. Generally, a large current flows through this cornering coil, which causes a reduction in the efficiency of the motor. That is, it was difficult to increase the efficiency of the electric motor because the cornering coil was used. Moreover, since the AC power supply, which is generally a commercial power supply, is used as the drive power source of the electric motor, the rated speed of the electric motor is mainly determined by the frequency of the commercial power supply, and a complicated control circuit is separately provided to use various rated speeds. Or, it is necessary to design and manufacture each rated rotation speed individually.

(C) Object of the Invention In view of the above problems, the present invention provides a small electric motor having a high efficiency by making a skeleton type small electric motor DC brushless.

(D) Configuration of the invention The present invention relates to a skeleton type small electric motor having a stator core and a stator winding, wherein the stator winding is a two-phase winding that alternately conducts electricity, and a permanent magnet provided on the outer periphery of the rotor core. A DC brushless system is provided by including a Hall element that detects the rotational position of the rotor, and a control unit that switches energization to the two-phase winding based on the output of the Hall element.

(E) Example Hereinafter, an example of the present invention will be described with reference to FIGS. 1 to 4. First, in FIG. 1, (1) is an electric iron plate having two arm portions. It is a stator core made by punching and stacking multiple sheets in a skeleton type, bolt holes (2), (3) used for mounting bearings, grooves for pole separation (4), (5), rotor (13) described later. Stator winding (10) having wide air gaps (6), (7) and narrow air gaps (8), (9), terminals (A), (B), (C), stator windings
It consists of a bobbin (11) that winds (10). The stator winding (10) is wound around a bobbin (11) having an iron core (12) and then mounted on the stator iron core (1). The stator winding (10) has two phases, one phase between terminals (A) and (C) and one phase between terminals (B) and (C). A rotor (13) is composed of a rotating shaft (14), a rotor core (15), and permanent magnets (16) and (17) provided on the outer circumference of the rotor core (15). Reference numeral (18) is a Hall element for detecting the rotational position of the rotor (13). Further, as described above, the gaps between the permanent magnets (16) and (17) of the rotor (13) and the stator core (1) are wide gaps (6), (7) and narrow gaps (8), (9). In such a case, the rotor (13) is always kept at a constant rotational position as shown in FIG. 1 or 1 from the state shown in FIG. 1 due to the balance of the magnetic attraction force.
Since it is generally known to stop at a position rotated by 80 degrees, the rotor (13) of the electric motor as described above always stops at any one of the above fixed positions.

FIG. 2 is an electric circuit diagram of a control unit for switching the energization to the fixed winding (10), and the stator winding (10) and the hall element (18) are the first.
Since it is the same as that shown in the figure, the same reference numerals are given. Reference numeral (19) is a comparator, and the non-inverting input terminal and the inverting input terminal are connected to the terminals (S) and (N) of the Hall element (18), respectively. (19) is a switching transistor connected in series with one phase of terminals (A) and (C) of the stator winding (10), the base terminal of which is a resistor (20) and a capacitor (21). It is connected to the output terminal of the comparator (19) through the integration circuit of. Reference numeral (22) is a diode for discharging the electric charge of the capacitor (21). (23) is a switching transistor connected in series with one phase of terminals (B) and (C) of the stator winding (10), and its base terminal has a resistor (24) and a capacitor (25). It is connected to the collector terminal of the transistor (28) through the integration circuit. Reference numeral (26) is a diode for discharging the electric charge of the capacitor (25). In addition, resistors (20), (24), and capacitors
The constants of (21) and (25) are set to a predetermined time that can prevent simultaneous turning on of the transistors (28) and (23) when the output of the comparator (19) is switched to the H level voltage and the L level voltage. There is.
Further, (27) is a constant voltage circuit.

When driving the small electric motor configured as described above, the second
When DC power is supplied to the terminal (V _cc ) in the figure, the rotor (13) first stops in the state as shown in FIG. 1, so that the terminals (S) and ( The output of N) is T in FIG.
It becomes the state of. Therefore, the output from the comparator (19) turns on the transistor (28) and the terminal (C) of the stator winding (10)
→ Current flows in the direction of terminal (A), wide gap (6) of stator core (1)
Becomes the N pole and the wide air gap (7) becomes the S pole, and the rotor (13) starts rotating to the left due to the repulsion of the permanent magnets (16) and (17). The rotation of the rotor (13) changes the outputs of the terminals (S) and (N) of the hall element (18) as shown in FIG. 90 rotor (13)
When rotated once, the output of the comparator (19) is switched as shown in Fig. 3, and at the same time the transistor (28) is turned off and the transistor (23) is turned on so that the terminal (C ) →
The current flows in the direction of the terminal (B), and the wide air gap (6) of the stator core (1) becomes the S pole and the wide air gap (7) becomes the N pole. Therefore, the rotor (13) is maintained in the counterclockwise rotation by the inertial force of the counterclockwise rotation and the newly generated attraction and repulsion action of the permanent magnets (16), (17). Less than,
Every time the rotor (13) rotates 180 degrees, the magnetic poles generated in the wide air gaps (6) and (7) of the stator core (1) are switched, and the left rotation of the rotor (13) continues continuously as described above. Is maintained at.

Incidentally, the rated speed of such an electric motor can be easily changed by the magnitude of the DC voltage applied to the terminal ( _Vcc ) as in a general DC motor.

FIG. 4 shows another embodiment of the present invention. In the figure, (28) is a stator core obtained by punching electric iron plates into a skeleton type and laminating a plurality of them, and bolt holes (29), (30 ) Is provided. A rotor (36) and a stator core (2
The widths of the gaps (31) and (32) with respect to 8) change according to the rotation angle of the rotor (36). (33) is terminals (A) ', (B)', (C) '
Is a stator winding having a stator winding (33)
A bobbin (35) having (34) is wound between terminals (A) 'and (B)' so that terminal (C) 'becomes an intermediate terminal and then the stator core
It is fixed to (28) by press fitting. That is, this stator winding (33) is one phase between terminals (A) 'and (C)' and terminal (B) ',
One phase between (C) 'is formed respectively. (36)
Is a rotor, and is composed of a rotary shaft (37), a rotor core (38), and permanent magnets (39) and (40) provided on the outer periphery of the rotor core (38). Reference numeral (41) is a Hall element for detecting the rotational position of the rotor (36). As mentioned above, the permanent magnet (39) of the rotor (36),
Even when the air gap between the stator core (28) and the stator core (28) is changed, the rotor (36) always stops at a constant rotational position due to the balance of the magnetic attraction force as described above.

The control unit shown in FIG. 2 can be used as the control unit for driving such an electric motor. However, terminal (A),
It is sufficient to connect (A) ', terminals (B), (B)', terminals (C), (C) ', respectively. If a DC power source is connected to the terminal (V _cc ), a magnetic field is generated and the rotor (36) is rotated as described above.

(F) Effect of the Invention The present invention provides a stator having two arms, an iron core narrowed between these arms, and an insertion hole narrowed in both arms formed by laminating a plurality of electric iron plates. A stator winding wound around the iron core, and an N pole and an S pole on the outer circumference housed in the insertion hole.
And a rotor having a magnetic pole, and a wide void portion and a void having a wide gap with the outer peripheral surface of the rotor so that the rotor is always stopped at a predetermined rotation position on the inner peripheral surface of the insertion hole. Alternately forming narrow voids that are narrowly configured,
Furthermore, a single position detector that detects the magnetic force of the rotor and outputs a signal is provided at a position that is moved a certain angle from the stop position of the rotor, and the fixed position is delayed by a predetermined time from the signal output of this position detector. Since it has a mechanism that changes the current supplied to the sub-winding, it can drive a motor with the same shape and size as a conventional skeleton type corner picking motor with DC power, eliminating the need for a corner picking coil as in the past. Therefore, the efficiency of the electric motor can be improved, and the size of the electric motor can be reduced. Furthermore, when switching the energization to the stator winding, the signal from the position detector was delayed for a predetermined time, so when changing the energization of the stator winding, it is possible to create a non-energized time zone in which the stator winding is not energized. it can. By providing such a non-energized time zone to reduce the residual magnetic flux, it is possible to reduce the influence of the residual magnetic flux of the magnetic poles generated on the stator and to make the next rising of the magnetic field quick. Therefore, even when the electric motor (rotor) is rotated at a high speed, the influence of the residual magnetic flux is reduced and the decelerating action on the rotor does not occur, and the efficiency of the electric motor can be improved.

[Brief description of drawings]

1 is a front view of an electric motor showing an embodiment of the present invention, FIG. 2 is an electric circuit diagram of a control unit used in the electric motor shown in FIG. 1, and FIG. 3 is a terminal of a hall element shown in FIG. 2 ( S), terminal (N),
FIG. 4 is an explanatory view showing the output of the comparator and the operating state of the transistor, and FIG. 4 is a front view of an electric motor showing another embodiment of the present invention. (1), (28) …… Stator core, (10), (33) …… Stator winding, (13), (36) …… Rotor, (15), (16), (39) , (40) ...
… Permanent magnets, (18), (41)… Hall elements.

Claims (1)

[Claims] 1. A stator having two arm portions, an iron core portion narrowed between these arm portions, and an insertion hole narrowed in the both arm portions formed by laminating a plurality of electric iron plates, and the iron core portion. And a rotor having two magnetic poles, an N pole and an S pole, on the outer periphery housed in the insertion hole, and the rotor is always provided on the inner peripheral surface of the insertion hole. Wide gaps with wide gaps and narrow gaps with narrow gaps are formed alternately with the outer peripheral surface of the rotor to stop at a predetermined rotation position. A single position detector that detects the magnetic force of the rotor and outputs a signal is provided at a position moved by a certain angle, and the energization to the stator winding is changed by delaying the signal output of this position detector for a predetermined time. A small electric motor with a mechanism.