JPH0541357U - Permanent magnet rotor and electric motor - Google Patents

Abstract

(57) [Abstract] [Purpose] In a permanent magnet rotor used in a brushless DC motor or the like, a permanent magnet rotor capable of preventing scattering of segment magnets and at the same time reducing an air gap to provide an efficient motor. Realize. [Structure] End plates 20a and 20b are installed at the ends of segment magnets 3a and 3b attached to the outer periphery of yoke 2, and the ends are fixed to each other. Therefore, the segment magnets 3 do not scatter even at high rotational speeds, and the central portion of the segment magnets directly faces the stator, so that the air gap can be reduced.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to the structure of a permanent magnet rotor used in a brushless DC motor or the like.

[0002]

[Prior Art]

 FIGS. 4 and 5 show an example of the structure of a conventional permanent magnet rotor. This permanent magnet rotor 10 has a shaft 1 to which a cylindrical yoke 2 made of a magnetic material such as soft iron is attached. A segment magnet 3 consisting of two sets of permanent magnets is attached to the outer periphery of the yoke 2 by an adhesive 4. In order to counter the centrifugal force during rotation, a cylindrical sleeve 5 made of a non-magnetic material such as stainless steel is attached to the outer circumference of the segment magnet 3 to prevent scattering.

FIG. 6 shows a cross section of an electric motor using the permanent magnet rotor 10. The permanent magnet rotor 10 is inserted between the stators 12 installed inside the electric motor body 11. Both ends of the rotor 10 are supported by bearings (not shown) or the like so as to maintain a constant gap (air gap) 13 with the stator 12. Then, by passing an electric current through the stator 12 which is an electromagnet, the rotor 10 rotates at a predetermined rotation speed.

[0004]

[Problems to be solved by the device]

 Since a DC motor having such a permanent magnet rotor can be made into a compact and highly efficient motor, it has been used in many fields as the miniaturization of various devices has advanced in recent years. In order to make this brushless DC motor even smaller and more efficient, it is important to reduce the air gap between the rotor and the stator to reduce the magnetic resistance in the magnetic circuit. For example, in the above-mentioned conventional DC motor, a non-magnetic sleeve is used to protect the segment magnets attached to the permanent magnet rotor from scattering. For this reason, it is necessary to ensure a gap greater than the thickness of the sleeve between the segment magnet, which is a permanent magnet that generates a field flux, and the stator. Furthermore, in addition to the dimensional error of the segment magnet, it is necessary to consider the dimensional error of the sleeve and the assembling error of these, so a large air gap between the sleeve and the stator can be secured to match these errors. There is a need to.

In view of the above problems, it is an object of the present invention to realize a permanent magnet rotor capable of firmly fixing the segment magnets and reducing the air gap. ..

[0006]

[Means for Solving the Problems]

 In order to solve the above problems, in the present invention, the segment magnets are fixed by restraining the movement of the end portions of the segment magnets. That is, in the permanent magnet rotor in which at least one set of segment magnets made of permanent magnets according to the present invention is attached to the outer periphery of the yoke, at least one end of the segment magnet along the axial direction of the yoke is arranged. The segmented magnets are characterized by having non-magnetic end restraining means for restraining their movement relative to each other.

As the end restraint means, it is effective to use an end restraint member that is formed in conformity with the shape in which the segment magnet is attached to the yoke.

Further, an electric motor having these permanent magnet rotors is also included in the range.

[0009]

[Action]

 By using such an end binding means, the segment magnets are bound to each other at their ends along the axial direction of the yoke and fixed to the yoke. Therefore, since the center of the segment magnet that generates the field flux can directly face the stator, the air gap with the stator can be significantly reduced. Therefore, the segment magnet can be firmly fixed to the yoke, the air gap can be reduced, and the magnetic resistance in the magnetic circuit of the motor can be reduced, so that a small and efficient motor can be realized. ..

Further, by using the end binding member formed in conformity with the shape in which the segment magnet is mounted on the yoke as the end binding means, the segment magnet can be mounted on the yoke with high precision. Since the segment magnets may be attached to the yoke in accordance with the formed end binding member, a special jig for deciding the attachment position of the segment magnets is unnecessary. Therefore, mass productivity is increased, and a permanent magnet rotor with excellent accuracy can be provided at low cost.

[0011]

【Example】

 Embodiments of the present invention will be described below with reference to the drawings.

1 and 2 show an outline of a permanent magnet rotor according to this embodiment. In the rotor 10 of this example, a cylindrical yoke 2 made of a magnetic material such as soft iron is attached to the shaft 1 as in the conventional rotor described above. The segment magnets 3a and 3b, which are permanent magnets, are attached by the adhesive 4. Further, in the rotor 10 of this example, the end plates 3.1a, b and 3.2a, b along the axis of the yoke 2 of the segment magnets 3a, b are connected to the end plates respectively. 20a, b are installed.

The end plates 20a and 20b are plate materials made of copper, and a pair of substantially rectangular opposing sides 21a and 21b are formed in an arc shape along the sectional shape of the segment magnets 3a and 3b.

Further, a shaft through hole 22 through which the shaft 1 passes is formed in the center thereof. Then, a pair of mounting holes 23 is formed on both sides of the shaft penetrating 22, and the end plates 20a, 20b are screwed into the screw holes 31 of the yoke 2 through the mounting holes 23. Is fixed to the yoke 2. Further, the end plates 20a, 20b are formed with a side wall 24 projecting to one side over the entire circumference thereof. The height of the side wall 24 is adjusted so as to reach the end portions 3.1a, b, 3.2a, b of the segment magnets 3a, b. Therefore, if the end plates 20a and 20b are attached from both sides of the yoke 2 with the segment magnets 3a and 3b attached to the yoke 2 at equal intervals, the end portions 3.1a, b and 3 of the segment magnets 3a and 3b. .2a and b are fixed to each other. That is, when the end plate 20a is attached to the one end 3.1a and one end b of the segment magnets 3a and 3b, the side wall 24 of the end plate 20a is attached to the end 3.1a and the end 3.1b. Set on the surface of. Therefore, even when the rotor 10 rotates and centrifugal force is generated, the segment magnets 3a and 3b are constrained from moving relative to each other by the end plate 20a, so that the segment magnets 3a and 3b are scattered from the yoke 2. There is nothing to do. Similarly, the other end portions 3.2a and 3.2b of the segment magnets 3a and 3b are fixed to the yoke 2 by the end plate 20b.

FIG. 3 shows a state in which the rotor 10 of this example is mounted on the electric motor. The rotor 10 in which the segment magnets 3a, 3b are firmly fixed to the yoke 2 by the end plates 20a, 20b is inserted into the stator 12 attached to the motor body 11. In the electric motor of this example, unlike the conventional electric motor shown in FIG. 6, the segment magnets 3a and 3b are fixed at their ends 3.1a, b, 3.2a and b, so that the segment magnets The centers of the magnets 3a and 3b face the stator 12 without any shield.

Therefore, the air gap 13 between the stator 12 and the segment magnets 3a and 3b can be set to be very narrow to the degree of assembly accuracy. Therefore, it is possible to secure a strong magnetic field flux related to the motor characteristics, so that it is possible to improve the motor characteristics and realize an efficient motor. By reducing the air gap 13, it is possible to downsize the motor.

Further, in this example, the end plates 20a, 20b are formed in a shape corresponding to the state in which the segment magnets 3a, 3b are fixed to the rotor 10. That is, the opposite sides 21a and 21b of the end plates 20a and 20b are formed in a shape to which the end plates 20a and 20b are attached in a state where the segment magnets 3a and 3b are fixed at the prescribed positions of the yoke 2. It Therefore, by attaching the segment magnets 3a and 3b to the yoke 2 with the adhesive 4 and setting the end plates 20a and 20b from both sides thereof, the segment magnets 3a and 3b are fixed at the prescribed positions. In the past, it was necessary to set the segment magnets at equal intervals in order to obtain the predetermined characteristics of the motor and to accommodate the mounting error within the air gap 13, and therefore a special jig was required. .. However, in the rotor 10 of this example, the segment magnets 3a and 3b are set to the prescribed positions by attaching the end plates 20a and 20b as described above, and therefore, the special treatment as in the conventional case is performed. No tools are needed. Further, by using the end plates 20a, 20b, it is possible to assemble with high accuracy. Therefore, a more efficient motor can be realized. As described above, in the rotor 10 of this example, not only the accuracy of the product is improved but also the productivity is improved. By manufacturing the electric motor using the rotor 10 of this example, good characteristics are obtained. It becomes possible to manufacture a simple electric motor at low cost.

It should be noted that, in this example, the description is based on the rotor using one set of segment magnets, but it is needless to say that the invention can be applied to a rotor using two or more segment magnets. The member forming the end plate is not limited to copper, but may be any non-magnetic material such as stainless steel, and its shape can be varied according to the number of segment magnets, the cylindrical shape, or the shape of other yokes. It is possible to adopt one.

[0019]

[Effect of the device]

 As described above, in the permanent magnet rotor according to the present invention, since the segment magnets are fixed to the yoke by the end restraining means, the air gap can be reduced while preventing the segment magnets from scattering. It is possible. Therefore, by using the permanent magnet rotor according to the present invention, problems such as scattering can be prevented and an electric motor with excellent characteristics can be realized. Particularly, in the rotor according to the present invention, since the end binding means for binding the movements of the segment magnets to each other is used, the segment magnets are used even in an electric motor used in a high rotation range and having a large centrifugal force. It can be fixed.

Furthermore, by using the end binding member formed in a predetermined shape, the segment magnet can be set accurately and easily at the specified position, which improves the production efficiency. Can be planned. At the same time, the rotor assembly accuracy can be improved.

[Brief description of drawings]

FIG. 1 is a perspective view showing a configuration of a permanent magnet rotor according to an embodiment of the present invention.

FIG. 2 is an explanatory view showing how the end plate is attached to the permanent magnet rotor shown in FIG.

3 is an explanatory view showing a cross section of an electric motor to which the permanent magnet rotor shown in FIG. 1 is attached.

FIG. 4 is a perspective view showing a configuration of a permanent magnet rotor according to a conventional example.

FIG. 5 is an explanatory diagram showing how a sleeve is attached to the permanent magnet rotor shown in FIG.

6 is an explanatory view showing a cross section of an electric motor to which the permanent magnet rotor shown in FIG. 4 is attached.

[Explanation of symbols]

 1 ・ ・ ・ Shaft 2 ・ ・ ・ Yoke 3 ・ ・ ・ Segment magnet 4 ・ ・ ・ Adhesive 5 ・ ・ ・ Sleeve 10 ・ ・ ・ Rotor 11 ・ ・ ・ Electric motor main body 12 ・ ・ ・ Stator 13 ・ ・ ・ Air Gap 20 ... End plate 21 ... End plate side 22 ... Shaft through hole 23 ... Mounting hole 24 ... End plate side wall 30 ... Screw 31 ... Screw hole

Claims (3)

[Scope of utility model registration request] 1. A permanent magnet rotor in which at least one set of segment magnets made of permanent magnets is attached to the outer periphery of a yoke, and the permanent magnet rotor is attached to at least one end of the segment magnets along the axial direction of the yoke. And a non-magnetic end binding means for binding the movement of these segment magnets to each other. 2. The permanent magnet rotor according to claim 1, wherein the end binding means is an end binding member formed in conformity with a shape in which the segment magnet is attached to the yoke. 3. An electric motor comprising the permanent magnet rotor according to claim 1.