JPS63103650A - Stepping motor - Google Patents

Abstract

PURPOSE:To effectively radiate heat generated from magnetic line, by a method wherein a bobbin molded integrally with an inner yoke is grasped to an outer yoke of plate form. CONSTITUTION:Magnetic wires 16 and 17 are wound respectively on both bobbins 32 and 33 molded integral with inner yokes 19, 20, and then an outer yoke 24 at lower side with a bearing member 8 press fitted is fixed to a synthetic resin 31. Then a rotor 1 is assembled in a hollow portion of the synthetic resin 31 and lower end of a rotary shaft 2 is supported by the bearing member 8, and further an outer yoke 23 with a bearing member 6 fixed is assembled on the synthetic resin 31. In this constitution, since the outside of both magnetic wires 16 and 17 is opened, heat generated from the magnetic wires 16 and 17 is positively radiated by convection of air at the outer circumference and temperature of the magnetic wires 16 and 17 is decreased.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a PM type stepping motor used in printers and the like.

[Conventional technology]

Conventionally, this type of stepping motor has a configuration shown in FIG. 4, for example.

That is, fi+ is a rotor, which is constructed by fixing a cylindrical magnet (3) to a rotating shaft (2).

(4) and (5) are outer yokes, and the upper outer yoke (4) has a substantially disc-shaped configuration, and a bearing part (6) for the rotating shaft (2) is fixed in the center, and the bearing part (6) A plurality of pole teeth (7) are formed concentrically around the portion (6). Further, the lower outer yoke (6) is formed into a substantially bottomed cylindrical shape, and a bearing portion (8) of the rotating shaft (2) is fixedly provided at the center of its bottom wall portion (5a). A plurality of pole teeth (9) are arranged concentrically around 8).
) is formed.

(10) and (11) are respectively outer yokes (5)
An annular inner yoke is inserted into the cylindrical part (5b) and arranged concentrically, and each outer yoke (
4).

(5) pole teeth (71 # +91 are arranged concentrically between the pole teeth [12)*(+31], and each yoke (41, [51, lol t #
[9) , f+ rock, 03) faces the outer peripheral surface of the rotor (1) with a predetermined gap in between.

(14) and (+5) are inner yoke t101 #
(11) and are formed integrally with the outer yoke (4).
), between the inner yoke (lO) and the outer yoke (6)
, a bobbin disposed between the inner yoke (11), (16)
) and (lη are the polar teeth (71, (12) and +9i
, (Bobbin (I4) and (
16), and is a magnetic wire wound through (4) to (1).
The stator (country) is made up of the symbols shown in 7).

Then, from a drive circuit (not shown), a magnetic wire (16),
By supplying a pulse current to Q, the rotor +1)
rotates.

This type of stepping motor is also disclosed in, for example, Japanese Patent Application Laid-open No. 121764/1986 (HO2K 37/14), which describes that the outer yoke and the inner yoke, each having pole teeth, are made of synthetic resin. A resin-integrated stator is disclosed, in which a winding frame portion of a winding wire and a bearing support portion supporting one end of a rotor shaft are simultaneously formed from the synthetic resin.

[Problem that the invention seeks to solve]

By the way, in the stepping motor, as is well known,
Since the output torque is proportional to the magnitude of the drive pulse current,
In order to obtain a small, high-output motor, it is necessary to pass a large current upstream, but on the other hand, when a large current is passed through the magnetic wire, the amount of heat generated from the magnetic wire increases.

However, in the conventional structure shown in FIG.
6), 07) are surrounded by the resin bobbins 04), +15), which are poor conductors of heat, and the cylindrical part (5b) of the outer yoke (5) that forms the circumferential side of the motor. ' t (' has the disadvantage that the heat generated from η is stored inside the motor.

In addition, in the case of what is shown in the above publication, as mentioned above,
The magnetic wire wound around the winding frame portion is blocked by the outer yoke or frame, resulting in poor heat dissipation.

This invention was made with the above points in mind,
In order to improve the heat dissipation of the magnetic wires wound on the outside of the pole teeth of each of the outer yoke and the inner yoke, it is an object of the present invention to provide a means that can fully open the outer circumferential side of the magnetic wires.

[Means for solving problems]

The present invention includes a stator comprising an inner yoke and an outer yoke each having a plurality of pole teeth facing each other with a gap between them on the outer peripheral surface of a rotor, and a magnetic wire wound around the outside of the pole teeth via a bobbin. In the stepping motor, the bobbin is integrally molded with the inner yoke from synthetic resin, and the bobbin is held between two substantially plate-shaped outer yokes each having a bearing portion that supports one end and the other end of the rotor shaft. It is characterized by this.

[Effect]

Therefore, according to the configuration of the present invention, the bobbin formed integrally with the inner yoke is sandwiched between the substantially plate-shaped outer yoke, and the outer circumferential direction of the magnetic wire wound around the bobbin is open. The heat generated by the magnetic wire is dissipated by convection of nearby air, and the temperature rise of the magnetic wire is suppressed.

〔Example〕

Next, the entire invention will be explained in detail with reference to FIGS. 1 to 3 showing one embodiment thereof. Note that the same symbols as in FIG. 4 above indicate the same or equivalent items.

In these drawings, (+9) and - have a plurality of (5) pole teeth r2+ by cutting and raising on the inner periphery of each.
+, an annular inner yoke with equally spaced hardness;
El and (24) are disk-shaped outer yokes in which a plurality (5) of pole teeth 5+ and (26) are formed at equal intervals by cutting and raising on the inner periphery of each, and both outer yokes +23+ , +24) has 5 coupling holes on the outer periphery.

28+ are transparently installed at equal intervals, and the upper outer yoke (23
) is provided with a lug (2) having a mounting hole (-).

(3I) is integrally molded with both inner yokes (19) e (20) and is located outside the bobbin H of the upper inner yoke α9) and the pole tooth of the lower inner yoke (1). The bobbin (33) is a molded synthetic resin, and this synthetic resin (31) has an outer yoke on the top and bottom surfaces.

Convex portions (2) that fit into the respective coupling holes (27) and 28 of the threshold.

(34 is provided protrudingly, and an outer yoke [23+, +24+ pole teeth (25+ #
(Nine grooves (G) into which the 2 (To) are inserted are formed.

Then, both inner yokes t" J e ("01 e both outer yokes (5) l t H1 both bobbins (321, (3
31 and both bobbins (supports).

The stator housing is constituted by magnetic wires H) t 07) wound around the respective parts.

Next, the assembly of the above embodiment will be explained.

First, insert magnetic wires (I6) into both bobbins E integrally molded on the inner yoke (191# (zo),
! , 07), and then the bearing part (8) is fixed to the lower outer yoke 4) which is completely press-fitted and fixed to the synthetic resin (31). That is, the protrusions (g) on the lower surface of the synthetic resin 01) are fitted into the coupling holes 4 of the outer yoke 4), and the outer yoke 24 is fixed by uniform heat welding.

Thereafter, the rotor (11) is assembled into the hollow part of the synthetic resin (31), the lower end of the rotating shaft [21 is supported by the bearing part (8), and the outer yoke (23) to which the bearing part (6) is fixed is attached.
1 on the synthetic resin (31), the convex portion (2) is fitted into each coupling hole of the outer yoke, and the rotating shaft (2) is supported by the bearing part (6). The convex portion (31) protruding from the hole is heat welded to complete the motor as shown in FIG.

Therefore, according to the configuration of the embodiment, both magnetic lines DI,
Since the outside of (17) is opened, the magnetic wire (16)
The heat generated from #'Jn is actively dissipated by the convection of the air in its external station, and the magnetic lines (+61, (+7
), and as a result, the drive pulse current can be increased to increase the output torque.

In addition, since both outer yokes (c) * (241) are disk-shaped, they can be manufactured using the same mold,
Furthermore, since a cylindrical portion, that is, a peripheral edge raised portion, like a conventional outer yoke is not required, a deep drawing process is not required, and there is an advantage that mold costs and press time can be reduced.

Furthermore, the motor configured as described above is assembled into a printer, etc. by using the ear piece (301) of the upper outer yoke (C) all around, but if the mounting part is made of resin as in recent years, the motor Although good heat conduction is not possible for the motor's own heat generation, the motor of the embodiment has an extremely good heat dissipation effect, so it is highly effective.

By the way, in the above embodiment, the inner yoke.

(Incorporated Foundation)) and made of synthetic resin, the bobbin □□□, @
Although the case where 31 was molded was explained, this invention
Not limited to this, the bobbins (9) and (g) are made of synthetic resin 0.
1) may be integrally molded with the inner yoke (19+1 (20)) and one outer yoke (24).

In this case, since the inner yoke (191, (20) and the outer yoke 4) are integrally molded on the bobbin u2, (33), the pole tooth (191*■0) of the inner yoke (191*■0)
2) It is easy to arrange the +1, (22=i outer yoke r24) concentrically with respect to the center of the bearing part (8), and the number of parts when assembling the motor is smaller than that of the rotor (1).
2 synthetic resin (31) and outer yoke (to), reducing cumulative errors in dimensional accuracy of each part,
There is an advantage that the motor structure can be made with high precision.

〔Effect of the invention〕

As described above, according to the stepping motor of the present invention, the conventional components surrounding the outside of the magnetic wire can be removed, so that the heat generated by the magnetic wire can be effectively dissipated by the convection of the air outside the magnetic wire. Can the heat dissipation effect be increased and the driving current to the magnetic wire? In addition, it is possible to increase the output of the motor.

[Brief explanation of the drawing]

1 to 3 show one embodiment of the stepping motor of the present invention, FIG. 1 is a perspective view, FIG. 2 is a sectional view of the main parts, FIG. 3 is an exploded perspective view, and FIG. 4 is a conventional stepping motor. FIG. 2 is a cross-sectional view of a stepping motor. (1)...Rotor, ill, +81...Bearing part, (16,), 117)...Magnetic wire, (liJl
, @0)...inner yoke, 21), so...pole tooth, (23+, shi4)...outer yoke, +25)
, (26)...pole tooth, 0I)...synthetic resin, 3
the law of nature. (Fuchi... bobbin, (g)... stator.

Claims (1)

[Claims] (1) A stator comprising an inner yoke and an outer yoke each having a plurality of pole teeth facing the outer peripheral surface of the rotor with a gap therebetween, and a magnetic wire wound around the outside of the pole teeth via a bobbin. In the stepping motor, the bobbin is integrally molded with the inner yoke from synthetic resin, and two substantially plate-shaped outer yokes each have a bearing portion that supports one end and the other end of the rotor shaft.
A stepping motor characterized in that the bobbin is clamped.