JPH11332176A - Geared actuator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a motor-driven geared actuator, the cost of which can be reduced easily by keeping low the number of item parts. SOLUTION: A motor 3, housed in the housing of a geared actuator, is constituted in such a way that one end 6a of the shaft 6 of the motor 3 is fixed to the housing and a rotor composed of a rotor holder 8 integrally formed with a gear section 8a and field magnets 9 arranged on the outer periphery of the holder 8 is attached to the shaft 6 from the other end of the shaft 6. In addition, coil bodies 10 are arranged at the outside of the magnets 9 with a prescribed clearance in between, and a magnetic ring 13 is interposed between the coil bides 10 and the housing. Therefore, the housing (magnetic path) of the actuator can be formed readily as a motor without being influenced by the cost and accuracy of dies.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a geared actuator, and more particularly to an improvement in a stepping motor housed in the geared actuator.

[0002]

2. Description of the Related Art Conventionally, a stepping motor is housed in a geared actuator, and the configuration of the stepping motor is as shown in FIG. FIG. 2 is a cross-sectional view of a main part of a stepping motor conventionally used for a geared actuator. In the figure, a metal 25 is fixed to an upper plate 21 made of a flat plate and a lower plate 22 drawn by a press by press fitting or the like, and a shaft 26 rotatably supported by the upper and lower metals 25 has a magnet 26. A ring-shaped field magnet 24 is arranged via a holder 23. On the other hand, a stator is arranged in the field magnet 24 with a predetermined gap therebetween. The stator is configured in two stages such that the coils 28 housed in the bobbin 27 made of synthetic resin are respectively covered by the yokes 29. It is a thing.

[0003] One end of the shaft 26 protrudes outwardly from a housing composed of upper and lower plates 21 and 22, into which a gear made of synthetic resin or the like is press-fitted to transmit motor output to the outside. It becomes. And, in order to suppress rampage due to thrust backlash of the rotor,
A washer 30 is inserted into one end of the shaft 26,
A ring-shaped spring washer 31 formed of a concentric circle is disposed between the lower plate 22 and the rotor on the other end side, and the rotor is attached to the upper plate 21 via the washer 30 by the action of the spring washer 31. It is being rushed.

[0004] The stepping motor thus constructed is housed in a housing of a geared actuator consisting of an upper case and a lower case, and various gears are connected to the output gear of the motor described above. The output was converted to an actuator and transmitted to the outside.

[0005]

However, in the above configuration, since the lower case constituting the housing of the stepping motor is drawn by pressing, the die cost is extremely high, and as a result, the unit cost of the motor is reduced. Invites a rise. In addition, when a part is formed by using a mold, it cannot be processed with high accuracy, so that there is a possibility that a trouble may occur between the part and other parts when the part is assembled.
Further, in such a stepping motor, an output gear made of a separate member must be inserted into a shaft portion protruding outward from the housing, so that the number of parts increases accordingly, and furthermore, the gear mounting It is necessary to control the position, the mounting strength, and the like, which are one of the factors that significantly deteriorate the workability.

Accordingly, an object of the present invention is to provide a geared actuator driven by a motor which solves the above-mentioned problem, reduces the number of parts, and can easily reduce the cost.

[0007]

According to the present invention, as a motor housed in a housing of a geared actuator, one end of a shaft is fixed to a housing, and a rotor is rotatably mounted on the shaft from the other end of the shaft. At the same time, the rotor is composed of a rotor holder in which a gear portion is integrated and a field magnet arranged on the outer periphery of the rotor holder, and a coil body is arranged in the field magnet through a predetermined gap. It is configured by interposing a magnetic ring body between the housings, and solves the above-mentioned problem by this configuration. The housing as a motor can be easily formed without being affected by mold cost and mold accuracy. (Magnetic path) can be formed.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A geared actuator according to the present invention is a geared actuator which accommodates a motor in a housing comprising an upper case and a lower case and transmits a predetermined power in conjunction with an output of the motor. The motor has one end of a shaft fixed to the housing, and a rotor rotatably mounted on the shaft from the other end of the shaft. The rotor is mounted on a rotor holder having an integrated gear portion and an outer periphery of the rotor holder. It consists of a arranged field magnet, and while arranging a coil body through a predetermined gap in this field magnet,
A magnetic ring is interposed between the coil and the housing. Further, it is effective that the rotor is urged in the axial direction by an elastic member inserted into the shaft, and the rotor is brought into contact with a part of the housing.

[0009]

FIG. 1 is a sectional view of a main part of a geared actuator according to an embodiment of the present invention. In the figure, 1
Is an upper case, and 2 is a lower case. A stepping motor 3 is housed in a housing composed of the upper and lower cases 1 and 2 formed by resin molding. A first gear 4 and a second gear 5 are sequentially connected to an output portion of the stepping motor 3, and the output of the motor 3 is finally converted into a predetermined power by the second gear 5 and is output to the outside. To be transmitted.

As a configuration of the stepping motor 3, first, one end 6a of the shaft 6 is fixed to a shaft holding portion 2a provided in the lower case 2 by press fitting or integral molding. An elastic member 7, for example, a coil spring, a leaf spring, or the like is inserted from the open end of the shaft 6, and a rotor rotatable with respect to the shaft 6 is mounted. The rotor has a rotor holder 8 formed integrally with an output gear portion 8a of a synthetic resin having excellent slidability,
The outer periphery of the rotor holder 8 has a field magnet 9 arranged in a ring shape.

A coil body 10 is disposed so as to face the field magnet 9 with a predetermined gap therebetween. The coil body 10 is made of a bobbin made of a synthetic resin, in particular, a bobbin made of a liquid crystal polymer. Each of the coils housed in the housing 11 is covered with a yoke 12 to form a two-stage structure. A magnetic ring 13 is interposed between the coil body 10 and the lower case 2 configured as described above.

Here, the magnetic ring body 13 is formed by cutting a flat plate made of a magnetic material into a predetermined length and then curling the flat plate into a ring shape. The magnetic ring 13 is mounted, and thereafter, the center hole of the cover plate 14 is fixed to the magnetic ring 13 while loosely fitting the output portion of the motor 3. At this time, the step of the rotor holder 8 is hooked on the inner peripheral portion of the cover plate 14, and the axial movement of the rotor is restricted at that location. In some cases, the other end of the shaft 6 is attached to the upper case 1 as shown in FIG.
The rotor urged in the axial direction by the elastic member 7 can be brought into contact with the protrusion 1 a provided on the upper case 1.

When the housing (magnetic path) of the motor 3 is constructed in this manner, a magnetic ring as in the present embodiment is used as compared with a conventional housing member which has been subjected to drawing by a press. If there is, there is no need to spend a great deal of money on the production of the mold. Moreover, since the shape of the magnetic ring is very simple, the precision is not strictly required, and there is no hindrance in assembling. Furthermore, since the output gear is integrally formed by resin molding of the rotor holder, the number of parts can be reduced by that amount, and each control in the gear mounting process becomes unnecessary, so that the workability is greatly improved. Can be.

[0014] Further, by bringing the rotor urged in the axial direction by the elastic member into contact with the projection provided on the upper case, a gap can be provided between the lid and the rotor holder. Since the sliding loss can be reduced and the rotor can be stably held, it is useful for preventing its vibration and noise.

The present invention is not limited to the above embodiment, but can be implemented with appropriate modifications without departing from the gist of the present invention. For example, the gear train meshed with the output gear of the motor may be of various combinations other than the present embodiment.

[0016]

As described above, according to the present invention, as a motor housed in the geared actuator housing, one end of the shaft is fixed to the housing, and the other end of the shaft is rotatable with respect to the shaft. At the same time as mounting the rotor, the rotor is composed of a rotor holder with an integrated gear portion and a field magnet arranged on the outer periphery of the rotor holder, and a coil body is arranged in the field magnet through a predetermined gap. By arranging a magnetic ring between the coil body and the housing, when forming the housing (magnetic path) of the motor, as compared with a housing member that has been subjected to drawing by pressing as in the prior art, as in the present embodiment. If a magnetic ring body is used, there is no need to spend a lot of cost on making the mold.
Cost reduction can be easily realized.

Further, by bringing the rotor urged in the axial direction by the elastic member into contact with the convex portion provided on the upper case, a gap can be provided between the lid and the rotor holder, so that the rotor can be mounted. While reducing the sliding loss,
Since the rotor can be stably held, its vibration or abnormal noise can be prevented.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part of a geared actuator according to an embodiment of the present invention.

FIG. 2 is a sectional view of a main part of a stepping motor conventionally used for a geared actuator.

[Explanation of symbols]

 1 upper case 2 lower case 3 stepping motor 6 shaft 7 elastic member 8 rotor holder 8a output gear section 9 field magnet 10 coil body 13 magnetic ring Body 14 ‥‥ lid

Claims (2)

[Claims] 1. A geared actuator in which a motor is housed in a housing consisting of an upper case and a lower case, and a predetermined power is transmitted in conjunction with an output of the motor, wherein the motor has one end of a shaft attached to the housing. And a rotor is rotatably mounted on the shaft from the other end of the shaft, and the rotor is composed of a rotor holder with an integrated gear portion and a field magnet arranged on the outer periphery of the rotor holder, A geared actuator comprising a coil body disposed in the field magnet via a predetermined gap, and a magnetic ring body interposed between the coil body and the housing. 2. The geared actuator according to claim 1, wherein the rotor is urged in an axial direction by an elastic member inserted into the shaft, and the rotor is brought into contact with a part of the housing.