JPH0332346A - Synchronous motor - Google Patents

Abstract

PURPOSE:To facilitate positional management of a rotary magnet and a pole chip by extending each pole chip through a pole board arranged facing one end face of a coil in the axial direction of a rotary shaft, and other action. CONSTITUTION:Pole chips 21 are extended through pole boards 23a, 23b faced with one end face of a coil 22 arranged in the axial direction of a rotary shaft 12. When power is fed to the coil 22, all pole chips 21 are excited with same polarity. Consequently, rotary force is exerted onto a rotary magnet 11 through the center of the pole chip 21 which have been faced each other before power supply to the coil 22, the center of pole of the rotary magnet 11 and the centers of auxiliary poles which do not face each other. When the direction of power supply to the coil 22 is switched sequentially, the rotary magnet 11 can be rotated continuously. Magnetic force functioning onto the rotary magnet 11 is regulated by varying the number of the pole chip 21. By such arrangement, positional management of the rotary magnet and the pole chip is facilitated and the assembling manpower and characteristic fluctuation of product are reduced.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a small synchronous motor mainly used as a drive source for timers and clocks. [Conventional technology]

As shown in FIG. 7, conventional synchronous motors of this type include a rotor 1 in which a rotating shaft 12 is equipped with rotating magnets 11 whose circumferential surfaces are magnetized with different magnetic poles alternately in the direction of rotation; A plurality of magnetic pole pieces 21 arranged opposite to the circumferential surface
．． 21' is excited by a coil 22 wound in the circumferential direction of a rotating magnet 11°, and a stator 2 is provided. Magnetic pole plates 23a and 23b are arranged facing each other on both end faces of the coil 22, and each of the magnetic pole plates 23a and 23b has a magnetic pole piece 21 and 21' extending therefrom, respectively. That is, the magnetic pole pieces 2 ] are placed on the inner periphery of the coil 22 in which the rotating magnet 1 ] is placed from both sides in the axial direction of the rotating shaft 12 .
21' has been inserted. The rotating magnet 11 and each magnetic pole piece 21, 21' are arranged as shown in FIG. 7(1).

[Problem to be solved by the invention]

This type of synchronous motor includes a rotating magnet 11, a magnetic pole piece 21.
The dimension of the gap between Ru. In the above conventional configuration, since the magnetic pole pieces 21 protrude from both sides of the rotating shaft 12 in the axial direction, the respective magnetic pole plates 23 a and 23 b disposed on both sides of the coil 22 must be accurately aligned. However, there are problems in that dimension management is troublesome and the number of assembly steps increases. The present invention aims to solve the above-mentioned problems, and it is possible to manage the positions of rotating magnets and magnetic pole pieces more easily than before, and to reduce the number of assembly steps than before, thereby achieving synchronization with less variation in product characteristics. The aim is to provide electric motors.

[Means to solve the problem]

In the present invention, in order to achieve the above object, each magnetic pole piece is
They each extend from a magnetic pole plate disposed opposite to one end surface of the coil extending in the axial direction of the rotating shaft. Furthermore, the higher the rated voltage applied to the coil, the smaller the number of magnetic pole pieces. Furthermore, it is preferable that members made of magnetic material are not disposed facing each other on both surfaces of the rotating magnet in the axial direction of the rotating shaft.

[Effect]

According to the above configuration, each magnetic pole piece extends from the magnetic pole plate arranged in a row on one end surface of the coil in the axial direction of the rotating shaft, so that the magnetic pole pieces are arranged opposite to one end surface of the coil. Predetermined operating characteristics can be ensured by accurately managing the position of the magnetic pole plates, which makes position management easier, and what's more, position management has become easier ()
Assembly man-hours are also reduced. As a result, variations in product operating characteristics are reduced, and products of stable quality can be supplied. In addition, if the number of magnetic poles is reduced as the rated voltage applied to the coil is higher, it is possible to adapt to specifications with different rated voltages without changing the diameter of the winding used in the coil or increasing or decreasing the number of turns of the winding. This can be done by simply replacing the magnetic pole plate, and not only can material costs be reduced by using economical windings, but also parts can be shared, reducing manufacturing costs. Furthermore, if members made of magnetic material are not placed facing each other on both surfaces of the rotating magnet in the axial direction of the rotating shaft, the magnetic force in the axial direction of the rotating shaft will not act on the rotating magnet. rotates smoothly and reduces noise. Furthermore, since the vibration of the rotor is reduced, wear of the bearing portion is reduced, leading to a longer life.

Embodiment 1 As shown in FIG. 1, a rotor 1 is formed by mounting one rotating magnet on a rotating shaft 12 via a mounting base 13. As shown in FIG. 2, the rotating magnet 12 is magnetized into a plurality of poles such that its circumferential surface has different magnetic poles at the intersection U in the rotation direction. Further, the angle (center angle) looking into the center of rotation of the rotating magnet 11 is set to be equal for each magnetic pole. On the other hand, the stator 2 includes a =1 coil 22 wound around a cylindrical coil bobbin 24 that surrounds the rotating magnet 11- so as to be coaxial with the rotating magnet 11. Magnetic pole plates 23a and 23b are disposed on both end faces to face each other, respectively. The magnetic pole plate 23a is held in a cylindrical housing 3 made of molded resin. Furthermore, four magnetic pole pieces 21 are extended from the inner circumferential edge of the magnetic pole plate 23a to be inserted into the space between the inner circumferential surface of the coil bobbin 24 and the circumferential surface of the rotating magnet 11. As shown in FIG. 2, two magnetic pole pieces 21 are arranged to face each other in the diametrical direction of the rotating magnet 11, and the straight line connecting each pair intersects with a slight deviation from 90 degrees. Further, the magnetic pole plates 23a are magnetically coupled at key points via bridging pieces 25 rising from the magnetic pole plate 23b, which does not include the magnetic pole piece 21. A protrusion 26 is protruded from the center of the magnetic pole plate 23b, and the rotating shaft 12 is inserted through the center of the protrusion 26. A slip ring 14 is inserted between the tip surface of the protrusion 26 and the mounting base 13. is sandwiched. That is, the magnetic pole plate 231) serves as a bearing at one end in the axial direction of the rotor. According to the structure described in 2 above, when the coil 22 is energized, all the m-poles 21 are excited to have the same polarity. =1 Immediately before power is applied to the coil 22, as shown in FIG. 2, the center of the magnetic pole piece 21, which is the main pole that controls the position of the rotating magnet 11, is within the column, Since the center of the magnetic pole piece 21, which is an auxiliary pole, is not opposed to the center of the magnetic pole of the co-rotating magnet 11, when the magnetic pole piece 21 is excited by energizing the coil 22, the rotating magnet 11 receives a rotational force. The deviation allows the rotating magnet 11 to continue rotating by sequentially switching the energizing direction of the coil 22, and operates as a well-known synchronous motor. Here, if the main pole and the auxiliary pole are exchanged, the direction of rotation of the rotating magnet 11 is reversed. In the above embodiment, the magnetic pole piece 21- is provided on the upper magnetic pole plate 23a in FIG. 1, but it may be provided on the lower magnetic pole plate 23b. By the way, referring to Fig. 3, regarding the dimensions of each part of the coil bobbin 24, a is 32zx maximum, b is 18cm, and C is 1cm maximum.
0. The relationship between the winding width t of the coil 22 and the number of ampere turns of the coil 22 is shown in FIG. Here, Fig. d (a) shows the rated voltage of 100 mm and the diameter of the winding of the coil 22 is 0.040, and Fig. 4 (b) shows the rated voltage of 200 V, and the upper line shows the coil 22's winding diameter. The diameter of the winding wire is O4R1, and the lower line shows the case where the diameter of the winding wire is 0.0311. As is clear here, if the diameter of the winding of the coil 22 is the same, the number of ampere turns is approximately twice as high as the rated voltage of 100V at the rated voltage of 200V. If the number of ampere turns is approximately doubled in this way, problems such as the inability to perform synchronous rotation will occur, so it will be necessary to change the specifications of the parts. In this case, changing the diameter of the winding of the coil 22 has been conventionally adopted as a relatively simple method. That is, FIG. 4(b)
As shown by the line below, the rated voltage is 200Vff! If the diameter of the winding is 003yz, the number of ampere turns will be approximately equal to the rated voltage of 100V. However, since the cost of winding wires increases rapidly when the diameter becomes 0.04 z or less, the use of thin winding wires leads to high costs. On the other hand, it is conceivable to use partial voltage wiping, a voltage dividing capacitor, a transformer, etc., but this would cause problems such as poor efficiency and increased space occupancy. Therefore, in this embodiment, the magnetic force acting on the rotating magnet 11 is adjusted by increasing or decreasing the number of magnetic pole pieces 21. In other words, the higher the rated voltage is, the smaller the number of magnetic pole pieces 2] is. This reduces the magnetic force acting on 11. For example, in the configuration shown in FIG.
04. Assuming that the coil 22 is formed using a winding wire of zx and the rated voltage is set to 200 to 240 cm, if the rated voltage is 120 V or less, it is sufficient to increase the number of magnetic pole pieces 21 by two. In this case, the magnetic pole piece 2 added for -20V
1-' may be provided on the magnetic pole plate 231) as in the configuration described as a conventional example. When temperature characteristics were measured for 1-il 22 having such a precept, the results shown in FIG. 5 were obtained. As is clear from the figure, there is almost no difference in characteristics, and it has been found that by adjusting the number of magnetic pole pieces 21, the purpose of adjusting the magnetic force acting on the rotating magnet 11 can be achieved.

[Example 21] In Example 1, the magnetic pole plates 23 a and 23 b were arranged on both sides of the rotating magnet 11 in the axial direction of the rotating shaft] 2, but in this example, a configuration in which the magnetic pole plate 23 b was removed was adopted. It is said that That is, as shown in FIG. 6, a non-magnetic bottom plate 27 is provided integrally with the coil bobbin 24, and the rotating shaft 12 is supported by a protrusion 28 provided on the bottom plate 27. Therefore, there is only one magnetic pole plate 23a, and since this magnetic pole plate 23a is formed in a ring shape and is open at a portion corresponding to one side of the rotating magnet 11, in the end, both sides of the rotating magnet 11 are open. The magnetic members are not placed facing each other. The other configurations are the same as those in the first embodiment, so their explanation will be omitted. According to the tank bottom, since no magnetic force acts in the axial direction of the rotating shaft 2, the rotation of the rotor 1 becomes smooth and the noise accompanying the vibration of the rotor 1 is reduced. Also,
Since the vibration of the rotor 1 is reduced, the radial force of the rotor 1 acting between the rotating magnet 11 and the magnetic pole piece 21 and the force in the radial direction of the rotor 1 acting between the rotating magnet 11 and the magnetic pole piece 21 are applied to the bearing portion. Only the own weight of the bearing acts on the bearing, reducing wear on the bearing and extending its life. Furthermore, by omitting the magnetic pole plate 23b, the magnetic pole plate 23b is omitted.
There is no need for caulking work to fix b, and the number of parts can be reduced and the work process can be simplified. In the configuration shown in FIG. 7 as a conventional example, the same effect can be obtained by forming an opening in the portion of the magnetic pole plate 23b facing the rotating magnet 11 and providing the magnetic pole piece 21 at the edge of the opening. . Effects of the Invention As described above, the present invention has each magnetic pole piece extending from a magnetic pole plate disposed opposite to one end surface of the coil in the axial direction of the rotating shaft. Predetermined operating characteristics can be ensured only by accurately managing the position of the magnetic pole plates that are placed facing the magnetic poles. This also reduces assembly man-hours. As a result, there is an advantage that variations in product operating characteristics are reduced and products of stable quality can be supplied. In addition, if the number of magnetic poles is reduced as the rated voltage applied to the coil is higher, it is possible to adapt to specifications with different rated voltages without changing the diameter of the winding used in the coil or increasing or decreasing the number of turns of the winding. This can be done by simply replacing the magnetic pole plate, which has the effect of reducing material costs by using economical windings, and reducing manufacturing costs by allowing parts to be shared. Furthermore, if members made of magnetic material are not placed facing each other on both surfaces of the rotating magnet in the axial direction of the rotating shaft, the magnetic force in the axial direction of the rotating shaft will not act on the rotating magnet. This has the advantage that the rotor rotates smoothly and noise is reduced. Furthermore, since the vibration of the rotor is reduced, wear of the bearing portion is reduced, leading to a longer life.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing Embodiment 1 of the present invention, FIG. 2 is a schematic configuration diagram showing the arrangement relationship between the rotating magnet and the magnetic pole piece in the same, and FIG.
4 and 5 are explanatory diagrams of the same operation as above, FIG. 6 is a sectional view showing a second embodiment of the present invention, and FIGS. 7(a) and 7(b) are a sectional view and a schematic configuration diagram showing the conventional example, respectively. It is. DESCRIPTION OF SYMBOLS 1... Rotor, 2... Stator, 11... Rotating magnet, 12... Rotating shaft, 21... Magnetic pole piece, 22... Coil, 23a, 23b... Magnetic pole plate.

Claims (3)

[Claims] (1) A rotor in which a rotating shaft is equipped with a rotating magnet whose circumferential surface is magnetized with multiple poles so that the magnetic poles alternate in the direction of rotation, and a plurality of rotating magnets are placed facing the circumferential surface of the rotating magnet. a synchronous motor comprising a stator having a coil for exciting magnetic poles, the coil being wound in the rotational direction of the rotor outside the magnetic pole, and each of the magnetic poles being wound in the axial direction of the rotating shaft; A synchronous motor characterized in that each of the motors extends from magnetic pole plates that are arranged opposite to each other on one end surface. (2) The synchronous motor according to claim 1, wherein the higher the rated voltage applied to the coil, the smaller the number of magnetic poles. (3) The synchronous motor according to claim 1, characterized in that members made of magnetic material are not disposed facing each other on both surfaces of the rotating magnet in the axial direction of the rotating shaft.