Abstract
Provided is a rotor of a brushed motor capable of reducing the occurrence of contamination during press-fitting of a commutator onto a knurling and reducing defect factors due to rotor contamination to improve productivity. In a rotor of a brushed motor having a commutator press-fitted onto a knurling of a shaft, an inclined surface is provided on an inner circumferential side of the commutator, and an angle of the inclined surface is configured to be smaller than an angle of an axial end portion of the knurling. The knurling may be configured to be at a position different from a shaft stepped end surface of the shaft and the knurling may be configured to be positioned axially inward of the commutator from an end surface of the commutator.
Claims
1. A rotor of a brushed motor, comprising a commutator press-fitted onto a knurling of a shaft, wherein an inclined surface is provided on an inner circumferential side of the commutator, and an angle of the inclined surface is smaller than an angle of an axial end portion of the knurling.
2. The rotor of the brushed motor according to claim 1, wherein the knurling is at a position different from a shaft stepped end surface of the shaft and the knurling is positioned axially inward of the commutator from an end surface of the commutator.
3. A brushed motor comprising the rotor of the brushed motor according to claim 1.
Description
BRIEF DESCRIPTION OF DRAWINGS
(1) FIG. 1 is an example of a rotor.
(2) FIG. 2 is an exploded perspective view of a first embodiment.
(3) FIG. 3 is an exploded cross-sectional view of the first embodiment.
(4) FIG. 4 is a cross-sectional view immediately before press-fitting of a commutator in the first embodiment.
(5) FIG. 5 is an enlarged view of a portion A in FIG. 4.
(6) FIG. 6 is a cross-sectional view after completion of press-fitting of the commutator in the first embodiment.
(7) FIG. 7 is an enlarged view of a portion B in FIG. 6.
(8) FIG. 8 is an exploded perspective view of a second embodiment.
(9) FIG. 9 is a cross-sectional view after completion of press-fitting of a commutator in the second embodiment.
(10) FIG. 10 is an enlarged view of a portion C in FIG. 9.
DESCRIPTION OF EMBODIMENTS
(11) Embodiments of the present invention will be described below with reference to the drawings.
(12) First Embodiment
(13) The present invention realizes a rotor in which the occurrence of contamination at the time of press-fitting of a commutator is reduced and manufacturing defect factors due to contamination is reduced.
(14) FIG. 1 illustrates an example of a rotor according to this embodiment. The rotor of this embodiment is constituted by a shaft 5 made of an iron material, a core 10 made of an iron material and press-fitted and fixed to the shaft, a commutator 15 in which a plurality of commutator pieces are arranged in a cylindrical shape and integrally molded with resin, and a coil 20 wound around the core and having an end portion connected to the commutator.
(15) This rotor is used by attaching one or more bearings to the shaft so as to be assembled to a motor.
(16) FIG. 2 illustrates an exploded perspective view of this embodiment. Two or more knurlings 25 are provided on the shaft 5 in a circumferential direction. In addition, the axial position of the knurling starts from a shaft stepped end surface 30.
(17) FIG. 3 illustrates an exploded cross-sectional view of this embodiment. An inclined surface 40 is formed on an inner circumferential side of the commutator 15. At this time, the inclined surface 40 on an inner circumference of the commutator can be located on a rear surface side 31 of the commutator 15 but may be located on a front surface side 32 of the commutator 15. Here, the rear surface side of the commutator 15 is a side where the commutator 15 faces the shaft 5 during press-fitting, which is a side where the core 10 is present. In addition, the angle of the inclined surface 40 on the inner circumference of the commutator may be the same or different between front and rear portions. Meanwhile, an inclined surface or a vertical surface is formed in an axial end portion 35 of the knurling 25. At this time, the angle of the axial end portion 35 of the knurling 25 (an angle formed between the inclined surface or the vertical surface at an end portion of the knurling 25 and a surface parallel to an axial direction of the knurling 25) is only required to be greater than zero and equal to or less than 90.
(18) FIG. 4 illustrates a cross-sectional view immediately before the press-fitting of the commutator in this embodiment and FIG. 5 illustrates an enlarged view of a portion A in FIG. 4. When the angle of the axial end portion 35 of the knurling 25 is assumed as and the angle of the inclined surface 40 on the inner circumferential side of the commutator 15 is assumed as , the relationship between the angles and , is set to be >. As a result, the press-fitting of the commutator 15 is always started from an extreme distal end portion 45 of the knurling 25 and the press-fitting is started as if the knurling 25 cuts into the commutator. Accordingly, contamination at the time of press-fitting decreases.
(19) FIG. 6 illustrates a cross-sectional view after the completion of the press-fitting in this embodiment and FIG. 7 illustrates an enlarged view of a portion B in FIG. 6. The press-fitting is completed with the axial end portion 35 of the knurling 25 protruding from an end surface 50 of the commutator 15.
(20) Second Embodiment
(21) FIG. 8 illustrates an exploded perspective view of this embodiment. A knurling 25 starts from a position away from a shaft stepped end surface 30. Setting of an angle between an axial end portion 35 of the knurling 25 and an inclined surface 40 on the inner circumferential side of a commutator 15 is as described in the first embodiment.
(22) FIG. 9 illustrates a cross-sectional view after the completion of the press-fitting in this embodiment and FIG. 10 illustrates an enlarged view of a portion C in FIG. 9. The press-fitting is completed at a position where the axial end portion 35 of the knurling 25 does not protrude from an end surface 50 of the commutator 15.
(23) Since the knurling does not pass through the commutator, contamination at the time of press-fitting will stay between the commutator and the knurling. As a result, the occurrence of contamination can be suppressed and contamination also can be prevented from jumping out from a press-fitting portion to the outside.
(24) The invention is not construed to be limited to the aforementioned embodiments and includes various types of variations. For example, the aforementioned embodiments have been described in detail in order to make the description of the invention easy to understand. Therefore, the embodiments are not necessarily limited to the ones provided with the whole configurations that have been described. In addition, part of the configuration of a certain embodiment can be replaced with the configuration of another embodiment, while it is also possible to add the configuration of a certain embodiment to the configuration of another embodiment. Part of the configuration of each of the embodiments can be subjected to addition, deletion, and replacement of another configuration.
REFERENCE SIGNS LIST
(25) 5 shaft 10 core 15 commutator 20 coil 25 knurling 30 shaft stepped end surface 31 rear surface side of commutator 15 32 front surface side of commutator 15 35 axial end portion of knurling 25 40 inclined surface 45 extreme distal end portion of knurling 25 50 end surface of commutator 15
