JPH0660261U - Rotor with permanent magnet for small electric motor - Google Patents

Abstract

(57) [Summary] [Purpose] To effectively suppress axial vibration of the rotor. [Structure] Two annular permanent magnet parts 5 having a central hole 4
And a magnet 2 having a connecting portion 6 for connecting the two permanent magnet portions 5 and a rotary shaft 3 inserted and fixed in the center hole 4, and the center hole 4 formed in the two permanent magnet portions 5 is axially arranged. And the connecting portion 6 is smaller than the permanent magnet portion 5 and is provided in a part of the circumferential direction of the shaft.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an improvement of a rotor having a permanent magnet for a small electric motor.

[0002]

[Prior art]

 According to Japanese Patent Publication No. 2-51352, a circumferential groove is formed in the center of a rotor made of a permanent magnet so as to correspond to a plurality of stator coils, thereby suppressing axial vibration of the rotor. . However, in the above technology, the hole length of the permanent magnet into which the shaft is inserted is long, and it is difficult to obtain dimensional accuracy in the case of integral molding, and when the permanent magnet is fixed to the shaft, the shaft slides. There are problems that the adhesive easily sticks out to the moving part (the part that protrudes from the permanent magnet) and that the rotor becomes large as a whole, so that large inertia easily appears.

[0003]

[The purpose of the device]

 An object of the present invention is to effectively suppress the axial vibration of the rotor while solving the above problems.

[0004]

[Solution of the device]

 Based on the above-mentioned object, the present invention comprises a magnet having two annular permanent magnet parts having a central hole and a connecting part connecting the two permanent magnet parts, and a rotating shaft inserted and fixed in the central hole. In addition, the central holes formed in the two permanent magnet parts are aligned in the axial direction, and the connecting part is smaller than the permanent magnet part and is provided in a part of the circumferential direction of the shaft. With the above configuration, the problems of dimensional accuracy, adhesive protrusion, and large inertia can be solved.

[0005]

【Example】

 1 to 4 show a rotor 1 of the present invention. The rotor 1 is composed of a magnet 2 and a rotary shaft 3 inserted and fixed in a center hole 4 of the magnet 2. The magnet 2 has two annular permanent magnet parts 5 having a central hole 4 and, for example, two connecting parts 6 connecting the two permanent magnet parts 5, and in this embodiment, they are integrated. It is a molded product. Of course, the ring-shaped permanent magnet parts 5 are alternately magnetized to the NS poles along the outer peripheral direction.

The connecting portion 6 has a semicircular arc shape having an outer diameter smaller than that of the permanent magnet portion 5, and is provided at a symmetrical position only in a part of the shaft in the circumferential direction. The central holes 4 formed in the two permanent magnet parts 5 are aligned in the axial direction, and therefore the rotating shaft 3 inserted therein passes between the two connecting parts 6 and the two central holes 4 are formed. Penetrates 4

In the case of this embodiment, the two connecting portions 6 are configured as a pair of semicircular arcs. Therefore, the inner peripheral surface of the semi-circular connecting portion 6 is in contact with the outer peripheral surface of the rotating shaft 3, but the outer peripheral surface of the rotating shaft 3 is exposed to the outside in the portion without the connecting portion 6. It will be. When the rotor 1 is assembled, the permanent magnet parts 5 face the two stator coils 7 arranged in the axial direction.

The reason why the connecting portion 6 is smaller than the outer diameter of the permanent magnet portion 5 is that the center portion of each of the permanent magnet portions 5 divided by the connecting portion 6 and the stator coil facing these permanent magnet portions 5 are This is because the generation of vibration can be effectively prevented by making the magnetic center of 7 coincide.

The reason why the connecting portion 6 is provided in a part in the circumferential direction of the shaft is that the magnet 2 is integrally molded, and therefore the length of the center hole 4 into which the rotating shaft 3 is inserted in the magnet 2 is short. It is easier to obtain the dimensional accuracy, and when the magnet 2 is fixed to the rotating shaft 3 by inserting the adhesive into the central hole 4 from between the connecting portions 6, the adhesive sticks out to the sliding part side of the shaft with respect to the bearing hole. This is because the problem of 1 is eliminated, and the overall weight of the magnet 2 becomes lighter so that the inertia becomes smaller.

If the adhesive sticks out from the center hole 4 and sticks out to the part of the rotary shaft 3 that projects from the magnet 2 for a long time, that is, the sliding part of the shaft, the mounting of the bearing will be adversely affected, but the center hole 4 Since the part of the permanent magnet part 5 exposed to the outside is exposed to the outside, the protruding part of the adhesive can be absorbed at that part, and the above inconvenience can be prevented.

If the two permanent magnet parts 5 and the connecting part 6 are integrally molded products, their positional relationship is determined in the process of molding the magnet 2, so that the two annular permanent magnet parts 5 are connected to the rotary shaft. In the process of assembling into magnet 3, the order of positioning becomes unnecessary, and when fixing the magnet 2 to the rotary shaft 3, it suffices to fix the two permanent magnet parts 5 as one body, that is, as one unit to the rotary shaft 3. This can be simplified as compared with the conventional one in which the two permanent magnet parts 5 are aligned with the rotating shaft 3 and fixed while adjusting the phase in the circumferential direction.

When only the axial distance between the two annular permanent magnet portions 5 is different, if the rotor 1 is manufactured to match the distance, the manufacturing process will be reduced in lot size. Therefore, in this case, as illustrated in FIG. 5, the magnet 2 is divided into two parts at the central portion of the connecting portion 6, and, for example, a ring-shaped space is provided between the two connecting portions 6 depending on the distance between the permanent magnet portions 5. By sandwiching the spacer 7 and changing the thickness of the spacer 7, that is, the dimension in the axial direction, it is possible to cope with a change in the interval between the permanent magnet portions 5.

By doing so, it is possible to prevent the rotor 1 from becoming a small lot. At this time, when the dimension of the connecting portion 6 on the side of each permanent magnet portion 5 in the axial direction is brought into contact so as to match one set of permanent magnet portions 5, the distance between the two permanent magnet portions 5 becomes the minimum. It is not necessary to sandwich the spacer 7 for the smallest lot, as long as it matches the one for the smallest lot.

[0014]

[Effect of device]

 In the present invention, the length of the central hole into which the rotary shaft is inserted is equal to the length of the two annular permanent magnet parts and does not function as a substantial hole at the connecting part. Since the center hole is open to the outside at the joint part, the magnet can be shortened, the dimensional accuracy can be easily obtained, and when fixing the magnet to the rotating shaft with adhesive, the adhesive from the open part of the joint part Since the adhesive can be inserted and excess adhesive can be retained at the open part, the adhesive does not stick out to the shaft sliding part, and the joint part has an outer diameter smaller than that of the permanent magnet part. And, because it is partially formed, the entire magnet becomes lighter, and the rotor's inertia can be reduced by that amount, and other unique effects can be obtained.

[Brief description of drawings]

FIG. 1 is a plan view of a rotor having a permanent magnet of a small electric motor of the present invention.

FIG. 2 is a side view of the rotor of the present invention.

3 is a cross-sectional view taken along a line AA of FIG. 1 taken along a plane including a rotor shaft.

4 is a plane perpendicular to the axis of the rotor in FIG.
It is sectional drawing of the arrow direction.

FIG. 5 is a sectional view of a rotor according to another embodiment of the present invention.

[Explanation of symbols]

 1 Rotor with permanent magnet of small electric motor 2 Magnet 3 Rotation shaft 4 Center hole 5 Permanent magnet part 6 Connecting part 7 Stator coil 8 Spacer

Claims (1)

[Scope of utility model registration request] 1. A magnet comprising two annular permanent magnet parts having a central hole and a connecting part connecting the two permanent magnet parts, and a rotary shaft inserted and fixed in the central hole.
The central holes formed in the two permanent magnet parts are aligned with each other in the axial direction, and the connecting part is smaller than the permanent magnet part and is provided in a part of the circumferential direction of the shaft. A rotor with a magnet.