JPH1042519A - Motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To significantly reduce the number of components, make the assembly work easy, realize cost reduction and, further, facilitate superior durability and a revolution at low speed with a high torque. SOLUTION: A motor 1 has a bobbin 12 which has an insertion hole into which a rotary shaft 21 is inserted at its center and in which a winding 11 is wound, a pair of cores 13 and 14 which hold the bobbin 12 between themselves in the axial direction and which have pole teeth 13a and 14a, alternately arranged along the outer circumference of the bobbin 12 respectively, a rotor 20 which has the rotary shaft 21 and driving magnets 25 which are so arranged as to face the pole teeth 13a and 14a, an output shaft part 30 which has a sun gear 31 which is coaxially provided on the rotary shaft 21 and an output shaft 32, planet gears 22a, 22b and 22c which are held on the rotor 20 so as to rotate freely and geared with the sun gear 31, and a fixing member 40 which has fixed teeth whose number differs from the number of the teeth of the sun gear 31. A planet gear mechanism is composed of the rotor 20, the sun gear 31 and the fixing member 40, and the rotation of the rotor 20 is transmitted to the output shaft 32.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric motor with a reduction gear mechanism, and more particularly, to an improvement in an electric motor used for equipment requiring low-speed rotation and high torque.

[0002]

[Prior art]

Conventionally, as an example of a small motor having a reduction gear mechanism (hereinafter simply referred to as a motor), there is one as shown in FIGS. This motor 50 is a small A
It is a C synchronous motor. And, roughly, a rotor 51 and a coil 52
Is wound around a bobbin 53 and a central shaft 51a of the rotor 51.
The rotation speed of the rotor 51 is reduced via a pinion 54 provided in the motor, the rotation speed is reduced, the torque is increased, and then the reduction gear train (in this case, the first wheel & pinion 56, 2 A third wheel 58, a third wheel 58, a fourth wheel 59, and a fifth wheel 60), and a terminal 61 that supplies power to the coil 52. FIG.
In FIG. 8 and FIG.
Only the main components are shown, and portions not necessary for the description here are omitted.

[0004] The motor 50 having such a configuration is provided with a rotor 5.
1 is sufficiently reduced by the reduction gear train to reduce the output shaft 55.
To obtain a low-speed rotation and high-torque output from the output shaft 55.

[0005]

[Problems to be solved by the invention]

[0006] However, the conventional motor 50 is not shown in FIG.
As can be seen from FIG. 5, a bobbin 53 is arranged on the outer periphery of the rotor 51, and the coil 52 is wound around the bobbin 53. In addition, the rotational force of the rotor 51 is applied to its central axis 51a.
In this case, the transmission is transmitted to the output shaft 55 via a reduction gear train composed of the first wheel 56 to the fifth wheel 60. Further, the output shaft 55 is inevitably connected to the motor 5.
0 and a terminal 6
1 also has a structure provided on the outer peripheral portion of the motor 50.

The conventional motor 50 has the above-described structure, and thus has various disadvantages as described below.

First, the diameter of the center shaft around which the coil 51 is wound in the bobbin 53 (here, referred to as the bobbin shaft diameter) needs to be at least as large as the diameter of the rotor 51, so that the bobbin shaft diameter becomes large. If the bobbin shaft diameter is large,
In order to obtain a predetermined number of turns, a large number of wires are required, and the cost of winding is increased. That is, the motor 5
Since the torque of 0 is proportional to A (ampere) × T (number of turns), it is sufficient to increase the number of turns to obtain a large torque when the ampere is constant, but the bobbin shaft diameter of the bobbin 53 becomes large. As the size increases, a longer wire is required to obtain a predetermined number of turns, and the winding cost increases.

If the bobbin 53 is arranged on the outer periphery of the rotor 51, the rotor diameter cannot be made large. If the rotor diameter is small, the magnetized width of the surface becomes narrow, so that the N pole and S pole adjacent to each other cancel each other out, and a desired torque cannot be obtained. That is, the rotation speed R of the motor 50, which is a small AC synchronous motor, is R = 120f
/ N (where f is the frequency and n is the number of motor poles)
Therefore, when n is small, the number of rotations increases and the rotation speed becomes high. Therefore, the motor 50 is rotated at a low speed,
It is advantageous to increase the number of poles in order to obtain a high-torque motor 50. However, if the number of poles is increased with a limited rotor diameter, the magnetization width becomes narrower as described above. The north pole and the south pole of each other cancel each other, and a desired torque cannot be obtained.

As described above, if the rotor diameter is small, the number of poles cannot be increased, so that the rotation speed becomes high in the end. In order to obtain a sufficiently high-speed rotation as the output, the speed reduction gear train is used. It is necessary to increase the number of stages, and the number of gears increases. As a result, problems in terms of cost and the number of assembly steps, space problems,
There are various problems such as noise and durability due to the high speed rotation.

Further, since the output shaft 55 is not at the center of the motor 50, when the motor 50 is to be mounted on any device, the degree of freedom of the motor mounting position in the device is reduced. It may be necessary to take extra area. Further, since the position of the terminal portion 61 is similarly provided on the outer peripheral portion of the motor 50, a similar problem may occur in terms of mounting space.

The present invention achieves a significant reduction in the number of parts,
It is an object of the present invention to provide an electric motor that can be easily assembled, can realize low cost, has excellent durability, and can perform low-speed rotation and high torque.

[0013]

In order to achieve the above object, in the electric motor according to the present invention, a bobbin wound around a winding having an insertion hole for inserting a rotary shaft as a center, and the bobbin being axially A pair of cores having pole teeth disposed so as to be intruded into each other on the outer periphery of the bobbin, a rotor having a driving magnet and a rotation axis disposed opposite to the pole teeth, and coaxially with the rotation axis. An output shaft portion having a sun gear and an output shaft, a planetary gear rotatably held by the rotor and meshing with the sun gear, and a fixed tooth meshing with the planetary gear and having a number different from the number of teeth of the sun gear. A fixed member formed in the direction is provided, and a planetary gear mechanism is constituted by the rotor, the sun gear, the planetary gears, and the fixed member, and the rotation of the rotor is transmitted to the output shaft.

Further, in the electric motor according to the present invention, a bobbin wound around a winding wire having an insertion hole for inserting a rotary shaft as a center and the bobbin held in the axial direction are inserted into the outer periphery of the bobbin. A rotor having a pair of cores having pole teeth arranged so as to be assembled, a driving magnet and a rotating shaft arranged to face the pole teeth, and a gear having a sun gear in the circumferential direction of the rotating shaft; An output shaft provided coaxially with the rotating shaft, a planetary gear rotatably held on an outer peripheral portion of the output shaft and meshing with the gear portion of the rotor, and a number of teeth of the gear portion of the rotor meshing with the planetary gear. And a fixed member having a different number of fixed teeth formed in the circumferential direction. A planetary gear mechanism is configured by the rotor, the sun gear, the planetary gears, and the fixed member, and the rotation of the rotor is transmitted to the output shaft. .

Further, according to the invention of claim 3, according to claim 1,
Alternatively, in the electric motor described in 2, the terminal for supplying power to the bobbin is formed in the axial direction. Claim 4
In the above-described invention, in the electric motor according to the first, second, or third aspect, the bearing of the rotor is provided in the insertion hole of the bobbin. Furthermore, in the invention described in claim 5, according to claim 1,
2. The motor according to claim 2, 3 or 4, wherein the planetary gear is 12
Three are provided at 0 degree intervals.

The electric motor of the present invention is used for equipment which rotates at a low speed and requires a high torque. This motor does not have a configuration in which a bobbin is provided on the outer periphery of the rotor, but has a configuration in which the magnet of the rotor is disposed on the outer periphery of the bobbin. Even if there is, the number of windings can be increased.

As described above, when the number of windings is large, the motor torque can be increased. When the same motor torque is to be obtained, the wire length can be reduced, so that the cost of the wire can be reduced. Can be. In addition, since the rotor can also have a large diameter, the magnetization width can be widened and the motor torque can be increased. Furthermore, if the magnetization width is the same, the number of motor poles can be increased and the rotation speed of the rotor can be suppressed, so that noise can be reduced and the life can be prolonged.

Further, the electric motor of the present invention has a planetary gear mechanism, and by operating this planetary gear mechanism as a differential gear, the rotation of the rotor is reduced at once, and the reduced rotation is output from the output shaft. This eliminates the need for a multi-stage gear train as a speed reduction mechanism, greatly reducing the number of parts, enabling downsizing and cost reduction, and greatly reducing the number of assembly steps, resulting in high torque. An electric motor optimal for equipment requiring low-speed rotation can be provided.

In addition, since the output shaft is provided on the central axis of the motor, the degree of freedom of the mounting position of the motor is increased, and the size of the entire device to which the motor is mounted is reduced, or the space of the device is reduced. Can be used effectively.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. Here, an example applied to a small AC synchronous motor will be described.

The small AC synchronous motor 1 serving as this electric motor
Is roughly composed of an electromagnetic magnet unit 10, a rotor 20, an output shaft unit 30, and a case 40 serving as a fixing member.

The electromagnetic magnet unit 10 includes a bobbin 12 around which a coil 11 serving as a winding is wound, and a plurality of bobbins 12 which sandwich the bobbin 12 from the axial direction and are arranged so as to be interdigitated with each other on the outer periphery of the bobbin 12. A pair of cores 13 and 14 having pole teeth 13a and 14a, respectively;
2. a boss 15 having a pair of cores 13 and 14 fixed therein and having an insertion hole 15a into which the rotating shaft 21 of the rotor 20 is inserted;
And a terminal 16 for supplying power to the coil 11.

The bobbin 12, as can be seen from FIG.
The boss 15 is used as the winding diameter portion 12a around which the coil 11 is wound.
The outer diameter w, which is the bobbin shaft diameter, can be made extremely small since it is sufficient to have an inner diameter into which the large diameter portion 15d can be inserted.

The core 13 has a terminal 1 on its side surface.
A hole 13b is provided for projecting the coil 6 to the outside, the terminal 16 is projected to the outside from the hole 13b, and power is supplied to the coil 11 via the terminal 16. Further, a small diameter portion 15 on one side of the boss 15 is provided at the center of the core 13.
b, a boss mounting hole 13c for fixing the boss 15 is provided, and a case 4 is provided near the end.
A case mounting hole 13d for fixing the 0 claw 41 is provided.

The core 14 is also provided with a boss mounting hole 14b for inserting the small diameter portion 15c on the other side of the boss 15 and fixing the boss 15.

The electromagnetic magnet section 10 having such a configuration
Is assembled as follows. First, the small diameter portion 15b of the boss 15 is inserted and fixed in the boss mounting hole 13c of the core 13. Next, the boss 15 is attached to the center axis of the bobbin 12 on which the coil 11 is wound and the terminal 16 is attached.
The large diameter portion 15d is fitted and fixed. And core 1
The small diameter portion 15c of the boss 15 is inserted into the boss mounting hole 14b of No. 4 and fixed.

The rotor 20 has a circular axial end face shape, and a cylindrical protrusion 24 protruding in the axial direction is formed on the outer peripheral portion thereof, and has a substantially U-shaped cross section. At the center of the axial end surface of the rotor 20, a rotating shaft 21 protruding from both sides in the axial direction is provided, and further, a supporting shaft 23a for rotatably supporting the pinions 22a, 22b, 22c serving as planetary gears. , 23b and 23c are provided on the same circumference at intervals of 120 degrees. A magnet 25 is mounted on the inner peripheral surface of the protruding portion 24 of the rotor 20.

The rotor 20 having such a configuration is similar to the rotor 2 shown in FIG.
By inserting the 0 rotation shaft 21 into the insertion hole 15 a of the boss 15, it is rotatably attached to the electromagnetic magnet unit 10. When the rotor 20 is attached to the electromagnetic magnet 10 in this manner, the driving magnet 25 of the rotor 20 includes the pole teeth 13 a of the pair of cores 13, 14.
14a.

The output shaft 30 is provided with a gear 3 serving as a sun gear.
1 and an output shaft 32 protruding from the center of the gear portion 31. Then, the gear portion 31 (hereinafter, the sun gear 31)
) Is rotatably supported by a rotating shaft 21 protruding from the center of the end face of the rotor 20.
And three pinions 22a attached to the rotor 20,
22b, 22c (hereinafter, planetary gears 22a, 22b, 22
c). In addition, the planetary gears 22a, 22
The effective length h of the gear portions b and 22c is about twice as large as the thickness t of the sun gear. Therefore, the output shaft 30 is attached to the rotor 20, and the planetary gears 22a, 22
Assuming that the sun gear 31 is meshed with the sun gear 2b, 22c, the planet gears 22a, 22b, 22c are in a state in which about half of the length h is further protruded from the sun gear 31.

The case 40 is structured so as to cover the entirety of the above-described electromagnetic magnet unit 10 with the rotor 20 and the output shaft unit 30 attached thereto.
3 and inserted into the case mounting holes 13d.
3 to be fixed.

A bearing portion 42 for rotatably supporting the output shaft 32 is provided on the axial end surface of the case 40, and a plurality of fixed teeth coaxially with the bearing portion 42 are provided inside the case 40. A fixing gear 43 is provided, and a mounting hole 44 for mounting the device body with screws or the like is provided.

The diameter of the fixed gear 43 provided in the case 40 is the same as the diameter of the sun gear 31 of the output shaft 30, but the number of teeth is made different from the number of teeth of the sun gear 31. The number of teeth of the fixed gear 43 is reduced by one or two with respect to the number of teeth of the sun gear 31. In addition, conversely, 1 or 2
You may add more.

When the case 40 is fixed by inserting its claws 41 into the case mounting holes 13 d of the core 13, the output shaft 32 of the output shaft 30 passes through the bearing 42 of the case 40. As a result, the fixed gear 43 and the planetary gears 22a, 22b, 22c mesh with each other (see FIG. 2).

When assembled in this manner, the electromagnetic magnet unit 10, the rotor 20, the output shaft unit 30, and the case 4
0 is a structure in which the respective central axes are arranged coaxially. Further, a planetary gear mechanism is constituted by the rotor 20 having the planetary gears 22a, 22b, 22c, the output shaft portion 30 having the sun gear 31, and the case 40 having the fixed gear 42, and the planetary gears 22a, 22b, 22c, The sun gear 31 and the fixed gear 43 operate as differential gears.

Next, the operation of the small AC synchronous motor 1 configured as described above will be described.

When power is supplied to the coil 11 via the terminal 16, the rotor 20 rotates. Thus, the planetary gears 22 a, 22 b, and 22 c attached to the rotor 20 rotate on the circumference of the sun gear 31. That is, the planetary gears 22a, 22b, 22c are composed of the sun gear 31 and the fixed gear 4
3 so that each mounting shaft 23a,
The sun gear 3 is rotatable around 23b and 23c.
1 and around the fixed gear 43.

At this time, the sun gear 31 and the fixed gear 43 have slightly different numbers of teeth, and since the fixed gear 43 is fixed to the case 40, the planetary gears 22a, 22
b and 22c are 1 on the circumference of the sun gear 31 and the fixed gear 43.
During rotation, the sun gear 31 rotates by a small amount during that time.

As a specific example, the number of teeth of the sun gear 31 is 3
When the number of teeth of the fixed gear 43 is 30 and the number of teeth of the fixed gear 43 is 30, the planetary gears 22a, 22b, and 22c respectively
When the rotor makes one rotation on the circumference of the fixed gear, that is, when the rotor makes one rotation, the sun gear 31 moves by one tooth. As a result, the rotational speed of the rotor 20 can be reduced to 1/30. Therefore, even if the rotor 20 rotates at a high speed, the sun gear 31 rotates slowly in a sufficiently decelerated state, and a sufficiently reduced rotation speed can be obtained from the output shaft 32.

In the above-described first embodiment, the bobbin 12 and the rotor 20
However, the bobbin 12 can have a sufficiently small bobbin shaft diameter because the bobbin 12 has a structure in which each bobbin 12 is provided independently on a concentric axis. Can be bigger. If the number of windings is large, the motor torque can be increased (the motor torque is proportional to ampere times the number of windings), so that if the same motor torque is to be obtained, the wire length can be reduced. Therefore, it is possible to reduce wire rod costs.

Further, since the rotor 20 can have a large diameter, a large magnetization width can be obtained and the motor torque can be increased. Furthermore, with the same magnetization width, the number of motor poles can be increased, and the number of rotations can be reduced. That is, since the rotation speed R is represented by R = 120 f / n (n is the number of poles), the number of rotations decreases as the number of poles increases. Also, if the rotor diameter is large, it is possible to increase the magnetization width to some extent and increase the number of poles, and to further reduce the number of revolutions while maintaining a constant motor torque. .

As described above, the fact that the rotor diameter can be increased means that the rotation speed of the rotor 20 can be suppressed, the number of deceleration stages can be reduced, noise can be reduced, and the life can be extended. can do.

Further, the small AC synchronous motor 1 according to the first embodiment has planetary gears 22a, 22b, 22c.
, The output shaft 30 having the sun gear 31, and the case 40 having the fixed gear 43 constitute a planetary gear mechanism, and the planetary gears 22 a, 22 b, 22
c, the sun gear 31 and the fixed gear 43 operate as differential gears, so that the rotation of the rotor 20 is reduced at once,
Since the decelerated rotation is output from the output shaft 32, a multi-stage gear train as a reduction mechanism is not required, the number of parts can be greatly reduced, and downsizing, cost reduction, and reduction in assembly man-hours can be achieved. As a result, it is possible to provide an electric motor that is optimal for equipment that requires high torque and low-speed rotation.

In particular, when configuring the planetary gear mechanism,
Since the rotor 20 and the case 40 are also used as one element of the mechanism, the number of parts can be greatly reduced as compared with the conventional structure (see FIGS. 7 and 8), and the assembling time and the number of steps can be greatly reduced.

Further, the electromagnetic magnet unit 10, the rotor 2
0, a structure in which the respective central axes of the output shaft section 30 and the case 40 are provided on concentric axes, that is, the output shaft 32 is a small AC
Since the structure is provided on the center axis of the synchronous motor 1, the degree of freedom of the mounting position of the small AC synchronous motor 1 is increased, and the size of the entire device to which the small AC synchronous motor 1 is mounted is reduced, or Effective use of space can be achieved.

Further, since the terminal 16 for supplying power to the coil 11 is provided on the axial end face side of the small AC synchronous motor 1, the outer diameter of the small AC synchronous motor 1 does not increase, and the size of the entire device becomes small. Or effective use of equipment space.

The above embodiment is an example of a preferred embodiment of the present invention, but the present invention is not limited to this, and various modifications can be made without departing from the spirit of the present invention. is there. For example, a planetary gear mechanism that operates as a differential gear may have the configuration of the second embodiment as shown in FIGS.

The motor of the second embodiment shown in FIGS. 3 to 6 is the same as the motor of the first embodiment of FIGS. 1 and 2 except for the configuration of the planetary gear mechanism. Are given the same reference numerals. The planetary gear mechanism shown in FIGS. 3 to 6 is provided with a gear 26 as a sun gear on the rotating shaft 21 of the rotor 20, and a planetary gear on the output shaft 30.
For example, three gears 33a, 33b, and 33c are provided on the same circumference at 120-degree intervals, and a fixed gear 45 is provided on the inner peripheral surface of the case 40. The gears 33a, 33b, and 33c serving as planetary gears are
0 and the fixed gear 45 of the case 40
And mesh with the gear 26 and the fixed gear 45, respectively. The gear 26 provided on the rotor 20 and the fixed gear 45 having a plurality of fixed teeth provided on the case 40 have different numbers of teeth.

Even with such a configuration, the gear 26 provided on the rotor 20 and the gear 3 provided on the output shaft 30
A planetary gear mechanism is constituted by 3a, 33b, 33c and a fixed gear 45 provided on the case 40, and the planetary gear mechanism operates as a differential gear.

Therefore, when the rotor 20 rotates, the gear 26 provided on the rotor 20, the gears 33a, 33b, 33c provided on the output shaft 30, and the fixed gear 45 provided on the case 40 are used as differential gears. By performing the above operation, the gears 33a, 33b, and 33c of the output shaft portion 30 move little by little on the gear 26 provided on the central shaft 21 of the rotor 20. As a result, the output shaft 32 rotates at a rotation in which the rotation speed of the rotor 20 is sufficiently reduced. Specifically, for example, if the number of teeth of the gear 26 is 30 and the number of teeth of the fixed gear 45 is 120, the rotor 2
When “0” makes one rotation, the output shaft unit 30 makes １ ／ rotation. With this configuration, the same effect as in the first embodiment can be obtained.

In each of the above-described embodiments, an example in which three planetary gears are provided at 120-degree intervals has been described. However, by providing three planetary gears at 120-degree intervals in this manner, a good balance is provided. Operation with high stability becomes possible.
However, the number of planetary gears is not limited to three, and may be, for example, one or four or more.

In each of the above embodiments, the small AC
Although the example of the synchronous motor 1 has been described, the present invention can be applied to other various electric motors.

[0052]

As described above, in the electric motor according to the first aspect, the bobbin wound with the coil, the rotor, the output shaft,
The central axes of the fixing members (cases) are arranged on the same axis, and a planetary gear mechanism is constituted by the rotor, the sun gear, the planetary gears, and the fixing member. Since it is configured to operate as a gear, and the magnet of the rotor is arranged on the outer periphery of the bobbin, the bobbin can have a smaller bobbin shaft diameter,
The number of turns can be increased even for wires of the same length. As described above, if the number of windings is increased, the motor torque can be increased. If the same motor torque is to be obtained, the wire length can be shortened, so that wire material cost can be reduced.

Also, since the rotor can have a large diameter, the magnetization width of the N pole and the S pole can be increased, and the motor torque can be increased. With the same magnetization width, the number of poles can be increased, the number of rotations can be reduced, and the rotation can be prevented from rotating at an unnecessarily high speed. Also, if the rotor diameter is large, it is possible to increase the magnetization width to some extent and increase the number of poles, and to further reduce the number of rotations while maintaining a constant motor torque. . Since the number of rotations of the rotor is suppressed, it is not necessary to increase the number of deceleration stages, and noise can be reduced.
Lifespan can be extended.

Further, a planetary gear mechanism is constituted by the rotor, the sun gear, the planetary gears, and the fixed member (case), and the planetary gear mechanism is operated as a differential gear, whereby the rotation of the rotor is reduced at once. Since the decelerated rotation is output from the output shaft, a multi-stage gear train is not required as a reduction mechanism, the number of parts can be significantly reduced, and downsizing and cost reduction can be achieved.
The number of assembling steps can be greatly reduced, and an electric motor that is optimal for equipment requiring high torque and low speed rotation can be obtained.

In addition, since the output shaft is provided on the central axis of the motor, the degree of freedom of the mounting position of the motor is widened, and the size of the entire device to which the motor is mounted is reduced, or the space of the device is reduced. Can be used effectively.

According to the second aspect of the present invention, as a planetary gear mechanism, a gear as a sun gear is provided on the rotating shaft of the rotor, and a gear as a planetary gear is provided on the output shaft.
A fixed gear having a number of teeth different from the number of teeth of the rotor gear is provided on the inner peripheral surface of the case, and each gear of the output shaft is meshed with the gear provided on the rotor, and the gear of the output shaft and the case are fixed. The gears are meshed with each other, a planetary gear mechanism is constituted by the rotor section, the sun gear, the planetary gears, and the fixed member (case), and the planetary gear mechanism is operated as a differential gear. . With such a configuration, the same effect as the first aspect of the invention can be obtained.

According to the third aspect of the present invention, the terminal for supplying power to the bobbin is formed in the axial direction.
The outer diameter of the motor does not increase, and the size of the entire device can be reduced, or the space of the device can be effectively used.

Further, according to the fourth aspect of the present invention, since the rotor bearing is provided in the insertion hole of the bobbin, the winding diameter portion of the bobbin can be used as it is as the bearing portion of the rotor, and the configuration becomes compact and the number of parts increases. Can not be.

Furthermore, according to the fifth aspect of the present invention, since three planetary gears are provided at intervals of 120 degrees, a well-balanced and stable operation can be performed.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing a small AC synchronous motor according to a first embodiment of the present invention.

FIG. 2 is a partial cross-sectional view of a side surface when the small AC synchronous motor of FIG. 1 is assembled.

FIG. 3 is an exploded perspective view showing a small AC synchronous motor according to a second embodiment of the present invention.

FIG. 4 is a partial sectional view of a side surface when the small AC synchronous motor of FIG. 3 is assembled.

FIG. 5 is a partial perspective view illustrating a relationship between a sun gear, a planetary gear, and a fixing member illustrated in FIG. 3;

FIG. 6 is a perspective view showing a configuration of an output shaft shown in FIG. 3;

FIG. 7 is a side sectional view of a conventional small motor.

8 is a plan view showing the relationship between each gear and the output shaft of the conventional small motor of FIG. 7, viewed from the direction of arrow VIII in FIG. 7;

[Explanation of symbols]

 Reference Signs List 1 small AC synchronous motor (electric motor) 10 electromagnetic magnet part 11 coil (winding wire) 12 bobbin 12a winding diameter part 13 core 13a pole tooth of core 13 core 14a pole tooth of core 14 15 boss 16 terminal 20 rotor 21 rotating shaft 22a , 22b, 22c Pinions 23a, 23b, 23c serving as planetary gears Support shaft 25 Driving magnet 30 Output shaft unit 31 Gear unit (sun gear) 32 Output shaft 40 Case (fixing member) 42 Bearing unit 43 Fixed gear

Claims (5)

[Claims] 1. A bobbin wound around a winding having an insertion hole into which a rotary shaft is inserted, and pole teeth disposed so as to sandwich the bobbin in the axial direction and to interlock with each other on the outer periphery of the bobbin. A pair of cores, a driving magnet and a rotor having the rotating shaft disposed opposite to the pole teeth, an output shaft portion provided coaxially with the rotating shaft and having a sun gear and an output shaft, A planetary gear rotatably held by a rotor and meshing with the sun gear; and a fixing member meshing with the planetary gear and having a fixed number of teeth different from the number of teeth of the sun gear formed in a circumferential direction. And a sun gear, the planet gears, and the fixing member, which constitute a planetary gear mechanism, and transmit rotation of the rotor to the output shaft. 2. A bobbin wound around a winding having an insertion hole into which a rotary shaft is inserted, and pole teeth disposed so as to sandwich the bobbin in the axial direction and to interlock with each other on the outer periphery of the bobbin. A pair of cores, a rotor having a driving magnet and the rotating shaft arranged opposite to the pole teeth, and a rotor having a gear portion serving as a sun gear in the circumferential direction of the rotating shaft, and a rotor coaxial with the rotating shaft. An output shaft provided thereon, a planetary gear rotatably held on an outer peripheral portion of the output shaft and meshing with the gear portion of the rotor, and a number different from the number of teeth of the gear portion of the rotor while meshing with the planetary gear. A fixed member having fixed teeth formed in a circumferential direction, and a planetary gear mechanism configured by the rotor, the sun gear, the planetary gears, and the fixed member, and transmitting rotation of the rotor to the output shaft. Features Electric motor. 3. The electric motor according to claim 1, wherein a terminal for supplying power to the bobbin is formed in an axial direction. 4. A bearing for the rotor, wherein a bearing of the rotor is provided in the insertion hole of the bobbin.
An electric motor as described. 5. The electric motor according to claim 1, wherein three planetary gears are provided at 120 ° intervals.