JPH0541388U - motor - Google Patents

Abstract

(57) [Summary] [Object] The present invention relates to a motor, and it is an object of the present invention to realize a motor capable of effectively utilizing an alternating magnetic field formed by a coil and extracting a high output torque. [Structure] Permanent magnet rotor 1 whose outer peripheral surface is multi-pole magnetized
And a stator having a structure in which the coils 3a and 3b are wound and the yokes 2a to 2d integrally formed by a stator mold 12 made of an insulator are provided so as to face the outer circumference of the rotor 1, and the rotor 1 is integrated with the stator. A PM type stepping motor comprising a magnetic fixing plate 8 for fixing a bearing 7 supporting a shaft 5 that is provided to the stator to a stator, and a case 9 covering the stator and fixed to the fixing plate 8. The fixed plate 8 is provided with protrusions 8a to 8e that come into contact with the yoke 2a.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a motor, and more particularly to a PM type step motor.

[0002]

[Prior Art]

 7A and 7B are a longitudinal sectional view and a rear view of an example of a conventional step motor, respectively. Further, FIG. 7A is a vertical sectional view taken along the line AA of FIG. The step motor 20 in the figure is a PM type (permanent magnet type) step motor, and generally comprises a rotor 1 made of a permanent magnet made of a magnetic material whose outer peripheral surface is magnetized in multiple poles, and an outer peripheral surface of the rotor 1. In order to generate an alternating magnetic field in the yokes 2a to 2d, the yokes 2a to 2d that are integrally molded with the yokes 2a to 2d, and the yokes 2a to 2d, which are arranged via an air gap therebetween, the yokes 2a to 2d. A stator made up of coils 3a and 3b wound around 2d, and a fixed plate 8'made of a magnetic material for fixing the bearing 7 supporting the shaft 5 integrally fixed to the rotor 1 to the stator. Composed.

The rotor 1 has a cylindrical shape with its upper part closed, and the upper surface of the inner wall of the rotor 1 is pressed upward by the panel 4. The spring 4 is provided to prevent the rotor 1 from vibrating due to the alternating magnetic field generated in the yokes 2a to 2d by the coils 3a and 3b.

In order to efficiently use the alternating magnetic field generated in the yokes 2a to 2d, a case 9 made of a magnetic material is provided to cover the stator so as to contact the outer circumferences of the yokes 2a to 2d. The case 9 and the fixed plate 8'are fixed by caulking the case 9 at three caulking portions 9a to 9c.

[0005]

[Problems to be solved by the device]

 In the above-mentioned conventional motor, the yokes 2a to 2d are integrally molded with resin to form the stator mold 12 for the purpose of reducing the number of assembly steps and the cost for reducing the number of members for fixing the yokes. Here, in order to prevent the yokes from falling out of the status mold 12 and to prevent the yokes 2a to 2d from being deformed when the product is taken out of the mold during resin molding, no force is directly applied to the yokes 2a to 2d. The resin portions 12b and 12a are provided at the uppermost and lowermost portions of the yokes 2a to 2d for the purpose of ensuring so-called gates and protrusions. Since the resin portions 12b and 12a are interposed, the yoke 2a and the fixed plate 8'are not in contact with each other. Therefore, the magnetic path of the magnetic field generated between the yoke 2a and the fixed plate 8'is interrupted between the two, hindering the effective use of the alternating magnetic field. Therefore, there is a problem that the output torque of the step motor 20 can be reduced.

FIG. 8 is an enlarged vertical sectional view taken along line VIII-VIII of the caulked portion 9a of FIG. 7B. As shown in the figure, a resin portion 12a is interposed between the yoke 2a and the fixed plate 8 ', which causes a gap at the end portion between the yoke 2a and the fixed plate 8'. When the caulking is performed in this state, that is, when the caulking portion 9a is hit from the lower left direction in the figure with a kind of chisel called a caulking tool, the end of the fixing plate 8'is broken. As shown, it deforms so as to narrow the gap. Due to this deformation of the fixed plate 8, the bearing 7 is tilted, so that the air gap between the rotor 1 and the yokes 2b and 2c is varied, and the output torque of the step motor 20 is reduced and the output torque is reduced. There was a problem that the variation of the above became large.

The present invention has been made in view of the above problems, and provides a motor capable of effectively utilizing an alternating magnetic field formed by a coil and thus increasing output torque. With the goal.

[0008]

[Means for Solving the Problems]

 According to the present invention, a rotor having an outer peripheral surface magnetized with multiple poles, a stator having a structure in which a coil is wound and a yoke integrally molded with a molding material is provided so as to face the outer circumference of the rotor, In a motor including a fixing plate for fixing a bearing for supporting a shaft integrally provided on a rotor to the stator, the fixing plate is provided with a protruding portion that comes into contact with the yoke.

[0009]

[Action]

 In the present invention, since the protruding portion that abuts on the yoke is provided on the fixed plate, the magnetic field is concentrated on the protruding portion, so that the magnetic field from between the yoke and the fixed plate can be effectively utilized.

[0010]

【Example】

 1A and 1B are a vertical sectional view and a bottom view, respectively, of (B) of one embodiment of the present invention. Further, FIG. 7A is a sectional view taken along the line AA of FIG. In the figure, the same components as those of the conventional step motor 20 of FIG. 7 are designated by the same reference numerals, and the description thereof will be omitted. The difference between the fixing plate 8 of the step motor 10 shown in the figure and the fixing plate 8'of the step motor 20 shown in FIG. 7 is that the fixing plate 8 of the step motor 10 is provided with protrusions 8a to 8e. ..

Here, a more detailed configuration of the step motor 10 will be described. FIG. 2 shows a cross-sectional view of FIG. 3 shows a perspective view of the yokes 2b and 2d in FIG. The yokes 2a and 2c are arranged so that the yokes 2b and 2d shown in FIG. FIG. 4 shows a side view of the relationship between each of the yokes 2b and 2d and each of the yokes 2a and 2c. As shown in FIG. 3, each of the yokes 2a to 2c has a structure in which six pole tooth portions are formed on the inner peripheral side of the substantially disc shape so as to be intermittently projected in a direction orthogonal to the disc. These yokes 2a to 2d are sequentially arranged so that the respective disks are parallel to each other, and the pole tooth portions have a slight gap as shown in FIG. The structure is such that they mesh alternately with each other. Further, between the upper and lower pairs of the yokes 2a, 2b and 2c, 2d, the arrangement of the respective pole tooth portions is shifted by an angle which is half the distance between the centers of the adjacent pole tooth portions. ing. That is, the gap between the pole tooth portions of the yokes 2a and 2b and the center of one of the pole tooth portions of the yokes 2c and 2d coincide.

The coils 3a, 3b are wound so as to surround the meshed portions of the pole teeth of the yokes 2a, 2b and 2c, 2d. When a current is applied to these coils 3a and 3b, a magnetic field is generated between the upper and lower yokes having the pole tooth portions meshed with each other. Therefore, different types of magnetic poles are generated in the upper and lower yokes that mesh with each other. That is, as described above, different kinds of magnetic poles are generated in the adjacent pole tooth portions with a slight gap therebetween. As described above, the number of pole tooth portions meshed with each other is 24 in the vertical direction with respect to each of the two sets of yokes 2a, 2b or 2c, 2d, and the number of magnetic poles generated in each of the two sets of yokes is 24. Of these, different types of magnetic poles are 12 sets each.

Reference numeral 13 denotes an external connection terminal, which is connected to the coils 3 a and 3 b inside the stator mold 12. In this embodiment, the number of the external connection terminals 13 is six, three of which are connected to the coil 3a, and the remaining three are connected to the coil 3b. Further, each of the coils 3a and 3b is composed of two coils, and one end and the other end of the two coils are bundled and overlapped with each other and wound by the same number of turns. Further, one end of the two coils and the other end of the other coil are respectively connected to two terminals of the corresponding three terminals 13, and the other end of the one coil is connected. And one end of the other one is bundled and commonly connected to the remaining one terminal.

Power is supplied to the terminal to which the above-mentioned two coils are connected in common among these three terminals, and the remaining two terminals are grounded via separate switch circuits. By the connection, the two switch circuits are closed, so that the directions of the currents flowing in the two coils are opposite to each other. Therefore, the directions of the magnetic fields generated by the respective coils are opposite. Therefore, the direction of the magnetic field generated in the yoke around which these coils are wound can be controlled by opening and closing the switch circuit.

Further, the rotor 1 having a substantially cylindrical shape has a circumferential angle of 360 ° divided into 12 equal parts and is magnetized so that different kinds of magnetic poles are adjacent to each other. That is, 12 magnetic poles are magnetized, which is equal to the number of magnetic poles generated in the above-mentioned yokes 2a to 2d.

Next, the operation of the step motor 10 having the above configuration will be described. The magnetic poles are alternately generated in the upper and lower two sets of yokes 2a to 2d by the control of the switch circuit connected to the coils 3a and 3b as described above for the stator and the rotor 1. That is, for example, the magnetic poles are first generated only in the yokes 2a and 2b, and then the magnetic poles are generated only in the yokes 2c and 2d. Further, the magnetic poles generated in the respective yokes are reversed every time. Due to the attractive force and the repulsive force generated between the magnetic poles generated in the yokes 2a to 2d and the magnetic pole of the rotor 1, the magnetic poles generated between these two sets of yokes 2a, 2b and 2c, 2d. The rotor 1 rotates by half the angle between the adjacent magnetic poles at each switching timing.

Further, screw holes 8g and 8h provided at the lower left and upper right of the fixing portion 8 in FIG. 1B are used to fix the step motor 10 to a device to which the step motor 10 is applied. .. Further, the rotation of the step motor 10 is transmitted by connecting the exposed portion below the bearing 7 of the shaft 5 by a predetermined mechanism of an apparatus to which the step motor 10 is applied.

Next, a detailed description will be given of the configuration of the step motor 10 having the features of the present invention. FIG. 5 is an enlarged view of the V portion of FIG. The protruding portions 8a to 8e are the shaded portions of the fixing plate 8 made of sheet metal in FIG. 1B, that is, the portions corresponding to the caulking portions 9a to 9c in the circular portion where the fixing plate 8 contacts the case 9. A total of 5 portions, one between the crimped portions 9a and 9b and one between the crimped portions 9c and 9a, are at a height h which is slightly smaller than the thickness t of the sheet metal. It is formed by pressing so that it protrudes. The height h is equal to the thickness of the resin portion 12a of the stator mold 12 (the molding material) covering the bottom surface of the yoke 2a below the bottom surface of the yoke 2a. Therefore, as shown in FIG. 5, the upper surface of the protruding portion 8a contacts the bottom surface of the yoke 2a. Similarly, the upper surfaces of the protrusions 8b to 8e also come into contact with the bottom surface of the yoke 2a at their respective positions.

FIG. 6 is an enlarged sectional view taken along line VI-VI of the caulked portion 9a of FIG. 1 (B). As shown in the figure, since the upper surface of the protruding portion 8e abuts the bottom surface of the yoke 2a, the fixing plate 8 is not deformed when the caulking portion 9a is caulked as described above. Similarly, also in the crimped portions 9b and 9c, since the upper surfaces of the protruding portions 8b and 8c are in contact with the bottom surface of the yoke 2a, the fixing plate 8 is not deformed.

By providing the fixed plate 8 with the protrusions 8a to 8e in this manner, the fixed plate 8 contacts the bottom surface of the yoke 2a at the portion where the fixed plate 8 contacts the case 9. Therefore, in these portions, a magnetic path is formed between the fixed plate 8 and the yoke 2a, and the leakage of the alternating magnetic field from this portion is prevented. Therefore, the alternating magnetic field formed by the coils 3a and 3b is effectively utilized, and the output torque of the step motor 10 is increased.

Further, since the fixing plate 8 is brought into contact with the yoke 2a at the caulking portions 9a to 9c, the fixing plate 8 is not deformed when the fixing plate 8 and the case 9 are fixed by caulking. Therefore, the bearing 7 does not tilt, and the air gap between the rotor 1 and the yokes 2b and 2c does not vary, so that the output torque of the step motor 10 is not weakened and smooth rotation is realized. can do.

The present invention can be applied not only to the PM type stepping motor, but also to other types of motors in which the mutual relationship among the yoke, the case and the fixing plate is the same as that of this embodiment. ..

[0023]

[Effect of the device]

 As described above, according to the present invention, since the yoke is provided with the protruding portion to reduce the leakage of the magnetic field from between the yoke and the fixed plate, the alternating magnetic field formed by the coil is effectively utilized and the high output is obtained. The torque can be extracted.

[Brief description of drawings]

FIG. 1 is a diagram of an embodiment of the present invention.

2 is a cross-sectional view of FIG.

FIG. 3 is a perspective view of a yoke of a main part of FIG.

FIG. 4 is a partial side view of the yoke of the main part of FIG.

FIG. 5 is an enlarged view of a V portion of FIG.

6 is a sectional view taken along line VI-VI in FIG.

FIG. 7 is a diagram of a conventional example.

8 is a cross-sectional view taken along the line VIII-VIII of FIG.

[Explanation of symbols]

 1 Rotor 2a-2d Yoke 3a, 3b Coil 5 Shaft 7 Bearing 8 Fixing plate 8a-8e Projection 9 Case 9a-9c Caulking portion 10, 20 PM type step motor 12 Stator mold (molding material)

Claims (1)

[Scope of utility model registration request] 1. A stator having a rotor having an outer peripheral surface magnetized in multiple poles, and a stator provided with a yoke wound around a coil and integrally formed with a molding material so as to face the outer periphery of the rotor. A motor comprising a fixed plate for fixing a bearing for supporting a shaft integrally provided on the rotor to the stator, wherein the fixed plate is provided with a protruding portion that comes into contact with the yoke.