JP3007570U - Micro motor - Google Patents

Abstract

(57) [Abstract] [Purpose] When fixing the cylindrical bearing to the inner hole of the cylindrical field magnet by press fitting or other means during the mounting process of the cylindrical bearing and the cylindrical field magnet, By shortening the manufacturing process of the micromotor and reducing its cost by eliminating the contraction of the bearing that contacts the rotating shaft of the hole, and the damage and improper installation of the cylindrical bearing or cylindrical field magnet. [Structure] When a cylindrical field magnet is press-fitted and fixed to the outer periphery of a cylindrical bearing having bearings protruding inward at both ends, the inside of the through hole of the bearing will contract inward. A shrinkage absorption concave portion for preventing the above is formed on the outer peripheral portion of the bearing.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a micromotor that can shorten the manufacturing process and reduce malfunctions and noise due to bearings.

[0002]

[Prior art]

 A cup-shaped coreless motor M'for generating vibration showing a conventional micro motor will be described with reference to the sectional view of FIG. It should be noted that the description of the parts common to the description of the present invention will be given in the description of the embodiments of the present invention, and the same parts are designated by the same reference numerals and corresponding parts are designated by a dash.

In FIG. 7, 1 is a cylindrical housing made of a magnetic material, 2 is a cylindrical armature coil having a coreless structure, 3 is a 2-pole cylindrical field having N poles and S poles in the circumferential direction. Magnetic magnet, 4'is a cylindrical bearing, 5 is a rotating shaft, 6 is a retaining boss for preventing the rotating shaft 5 from coming off, 7 is sandwiched between the retaining boss 6 and the cylindrical bearing 4 ', and the rotating shaft 5 For a smooth rotation of the rotor, 8 is a commutator made up of a group of commutator pieces insulated from each other, 9 is a commutator hub made of an insulator to which the commutator 8 is attached, and 10 is one end of the rotating shaft 5. A ring for preventing the hub 9 from coming off by being attached to the hub, 11 is a brush stand having a through hole with a step in the central part attached to the opening at one end of the cylindrical housing 1, and 12 are not shown respectively. A pair that is electrically connected to the negative power supply side The brush, 13 has a step that engages with the step of the brush base 11, and the end caps 14-1 and 14-2 attached to the central through hole of the brush base 11 by means such as press fitting Positive and negative side power supply lead wires 15 electrically connected to the pair of brushes 12 respectively through through holes (not shown) of the brush base 11 are connected to the cup-shaped coreless motor M '. To generate vibration, it is formed in a shape such as a semicircle when viewed from the axial direction, and to generate large vibration, it is formed of high specific heavy metal such as Tungsten alloy. An eccentric cam fixed to the rotary shaft 5 protruding from the other end of the cylindrical housing 1 is a cylindrical coreless roller 16 including an armature coil 2, a rotary shaft 5, a commutator 8, a hub 9 and a let ring 10. Data.

In this cup-shaped coreless motor M ', an armature coil 2, a cylindrical field magnet 3, a cylindrical bearing 4', and a rotary shaft 5 are sequentially arranged inside a cylindrical housing 1. The open end of the cylindrical housing 1 is closed by a brush 12, a brush 12, lead wires 14-1 and 14-2, and an end cap 13 mounted on the brush base 11. The cylindrical bearing 4'is press-fitted into the inner circumference of the cylindrical field magnet 3 and fixed to the central portion of the other end of the cylindrical housing 1.

The armature coil 2 is electrically connected to the commutator 8 at one end thereof via a hub 9 made of an insulator. A cylindrical ringless rotor 16 is constructed by attaching a retaining ring 10 to one end of the rotary shaft 5 by means of press fitting or the like, and attaching it to the center of the hub 9 via the let ring 10. . Further, the coreless rotor 16 is rotatable by rotatably supporting the rotary shaft 5 by means of a cylindrical bearing 4 '. Since the cup-shaped coreless motor M'is used as a vibration generator, the semicircular eccentric cam 15 is attached to the other end of the rotary shaft 5.

According to the conventional cylindrical bearing 4'of such a cup-shaped coreless motor M ', the material is oilless metal, and the outer diameter of the cylinder has chamfered portions on both outer peripheral portions. Other than that, the outer diameter is the same. Further, the inner diameter of the cylinder is formed such that the inner diameter of the middle portion which does not contact the outer circumference of the rotary shaft 5 is larger than the inner diameter of both ends of the cylinder which contact the outer circumference of the rotary shaft 5.

Further, in the case of the cup-shaped coreless motor M ′ shown in FIG. 7, when the cylindrical bearing 4 ′ and the cylindrical field magnet 3 are relatively press-fitted, they are slightly larger than the inner diameter of the cylindrical field magnet 3. A cylindrical bearing 4'having an outer diameter is used. The mounting method by press-fitting will be described with reference to FIG. 8. The mandrel portion 17a of the guide pin 17 having the disk-shaped plate 17b at the other end is press-fitted into the inner hole of the cylindrical bearing 4 ′ to form a cylinder. The bearing 4'is inserted in the direction of arrow P (one end direction) in order to prevent the inner diameter from shrinking. Next, the cylindrical bearing 4'with the guide pin 17 inserted therein is pressed into, for example, the inner hole of the cylindrical field magnet 3 standing on the surface of the fixing jig 18.

Here, when the mandrel portion 17a of the guide pin 17 is pulled out from the cylindrical bearing 4 ', the elasticity of the cylindrical bearing 4'cannot completely eliminate the shrinkage of the inner diameter, so that the cylindrical shape Even if the rotating shaft 5 of the cup-shaped coreless motor M ′ is inserted into the inner through hole of the bearing 4 ′, the inner diameter of the inner through hole becomes small, and as a result, the rotating shaft 5 is inserted into the cylindrical bearing 4 ′. It has the drawback that it cannot be inserted into the inner hole of the '.

Therefore, the inner through hole of the cylindrical bearing 4 ′ contracted by being press-fitted into the inner hole of the cylindrical field magnet 3 is sized by a reamer or the like so that the inner diameter of the cylindrical bearing 4 ′ is reduced. It was formed to have a predetermined inner diameter.

However, in such a sizing process, the oil contained in the oilless metal that is the material of the cylindrical bearing 4 ′ may evaporate due to the heat generated during the sizing process, and the sizing process is completed. Since it is necessary to apply oil again later, and the number of manufacturing processes for the cup-shaped coreless motor M ′ is increased, the resulting cup-shaped coreless motor M ′ has a drawback that it becomes expensive.

Alternatively, the shrinkage of the inner diameter of the cylindrical bearing 4 ′ due to the pressure at the time of press-fitting is taken into consideration in advance to form the cylindrical bearing 4 ′ having an inner diameter slightly larger than the predetermined inner diameter of the cylindrical bearing 4 ′. The cylindrical bearing 4'is press-fitted into the inner hole of the cylindrical field magnet 3 and the rotary shaft 5 can be inserted into the inner hole of the cylindrical bearing 4'by contraction of the cylindrical bearing 4 '. There is a method of forming the inner diameter.

However, according to this method, the inner diameter of the cylindrical bearing 4 ′ is contracted to a predetermined value after press fitting due to the outer diameter tolerance of the cylindrical bearing 4 ′ or the inner diameter tolerance of the cylindrical field magnet 3 ′. It is necessary and this is not an easy manufacturing process.

Next, as another method for fixing the cylindrical bearing 4 ′ to the inner circumference of the cylindrical field magnet 3, there is a method as shown in FIG. 9.

Hereinafter, FIG. 9 will be described. First, the cylindrical bearing 4'is inserted into the inner hole of the cylindrical field magnet 3 from the beginning. Further, the mandrel portion 17a of the guide pin 17 is inserted into the inner hole of the cylindrical bearing 4 '. In this case, the mandrel portion 17a of the guide pin 17 is formed to have a length protruding from the other end opening of the cylindrical bearing 4 '. Next, the hollow cylindrical jig 19 is pressed into the mandrel portion 17a of the guide pin 17 protruding from the other end of the cylindrical bearing 4'from the arrow P '(counter arrow P direction), and the jig 19 and the plate. The pressure P ′ is applied in the direction facing each other with 17 b. As a result, the repulsive pressures (P and P ') spread the central portion of the cylindrical bearing 4'in the outer peripheral direction as shown in FIG. External pressure is applied to press-fit and fix the cylindrical bearing 4'into the inner hole of the cylindrical field magnet 3.

However, in the case of such a method, if the pressures P and P ′ applied to both ends are not properly controlled, the cylindrical bearing 4 ′ may be damaged or the cylindrical bearing 4 ′ may be damaged. Depending on the magnitude of the lateral pressure applied to the inside of the field magnet 3, the cylindrical field magnet 3 was damaged or was improperly attached.

[0016]

[Challenges of device]

 The present invention is based on the above-mentioned problems. In the process of mounting the cylindrical bearing and the cylindrical field magnet in the manufacture of a cup type coreless motor or other micro motor, the inner hole of the cylindrical field magnet is formed. When fixing the cylindrical bearing by press-fitting or other means, eliminate shrinkage of the portion of the inner hole of the cylindrical bearing that contacts the rotating shaft, damage to the cylindrical bearing or cylindrical field magnet, and improper mounting. As a result, the challenge was to shorten the manufacturing process of conventional micro motors such as cup-shaped coreless motors, and to reduce the cost.

[0017]

[Means for achieving the object of the invention]

 The problem to be solved by the present invention is, in a micromotor in which a cylindrical field magnet is press-fitted and fixed to the outer peripheral portion of a cylindrical bearing having bearing portions projecting in the inner diameter direction at both ends, the bearing and the cylindrical field magnet are combined. This can be achieved by forming a shrinkage absorption concave portion in the outer peripheral portion of the bearing in the relative press-fitting, which prevents the inside of the through hole of the bearing portion of the bearing from shrinking in the inner peripheral direction.

[0018] Another object can be achieved by forming the above-mentioned concave portion into a knurled portion on the outer periphery of the above-mentioned bearing or an uneven portion such as a concave-convex portion formed in the circumferential direction sequentially along the axial direction.

[0019]

[Action]

 The outer diameter of the bearing 4b that contacts the rotary shaft 5 at one end or both ends of the cylindrical bearings 4, 4-1, ... .., 4-3, the cylindrical bearings 4,4-1, ... -3, the force applied to the bearing portion 4b is absorbed by the portion of the cylindrical bearings 4, 4-1, ..., 4-3 that is not in contact with the rotating shaft 5 to contact the rotating shaft 5. The inward contraction of the bearing portion 4b can be suppressed.

Alternatively, as shown in the cylindrical bearings 4, 4-2 and 4-4, by forming an uneven portion 20 such as a knurl on the outer peripheral surface, a cylindrical field magnet is formed on the outer peripheral uneven portion 20. The force applied to the bearing portions 4b of the cylindrical bearings 4,4-2, 4-4 when press-fitting into the inner circumference of the rotor 3 is absorbed by the deformation of the outer peripheral uneven portion 20 to contact the rotating shaft 5. The inward contraction of the bearing portion 4b can be suppressed.

[0021]

[Example of device]

 An embodiment of a cup-shaped coreless motor M according to the present invention will be described below with reference to FIGS.

First Embodiment of the Invention A first embodiment of the cup-shaped coreless motor M according to the present invention will be described with reference to FIGS.

The other end opening of the cylindrical housing 1 made of a magnetic material is provided with a bearing holding portion 1a projecting inward in the axial direction at the center thereof, and the other end is an opening. An armature coil 2 of a cylindrical coreless rotor 16 is provided inside the cylindrical housing 1, and a cylindrical field magnet 3 located inside the armature coil 2 and a radial gap of the cylindrical housing 1 are provided. The armature coil 2 is arranged so as not to contact the cylindrical housing 1 and the cylindrical magnet 3. The cylindrical field magnet 3 has a cylindrical bearing 4 inserted into its inner hole by press fitting, and the cylindrical bearing 4 is formed to have a length protruding from the other end of the cylindrical field magnet 3. The protruding portion is press-fitted into and fixed to the inner hole of the bearing holding portion 1a of the cylindrical housing 1. That is, the cylindrical field magnet 3 is fixed to the cylindrical housing 1 via the cylindrical bearing 4.

The cylindrical bearing 4 used in the cup-shaped coreless motor M shown in FIG. 1 contacts the rotating shaft 5 at one end of the cylindrical bearing 4 as shown in FIGS. 2 (a) and 2 (b). The taper 4a is formed so that the outer diameter of the bearing portion 4b is smaller than the outer diameter of the central portion of the cylindrical bearing 4 which does not come into contact with the rotating shaft 5, and the cylindrical bearing is formed. The inner diameter r'of the central portion not in contact with the rotating shaft 5 is made larger than the inner diameter r of the ends of the both bearings 4b in contact with the rotating shaft 5 of No. The part 20 is formed.

[0024]

[Second Embodiment] Instead of the cylindrical bearing 4 of FIGS. 2A and 2B used in the cup-shaped coreless motor M shown in FIG. 1 of the first embodiment, as shown in FIG. It is also possible to use a cylindrical bearing 4-1 as shown in FIG. The difference between the cylindrical bearings 4 and 4-1 of FIG. 3 and FIGS. 2 (a) and 2 (b) is that the outer circumferential surface of the cylindrical bearing 4-1 of FIG. Not not.

[0025]

[Third Embodiment] Further, in place of the cylindrical bearing 4 of FIGS. 2 (a) and 2 (b) used in the cup-shaped coreless motor M shown in FIG. 1 of the first embodiment, It is also possible to use a cylindrical bearing 4-2 as shown in FIG. The difference between the cylindrical bearings 4 and 4-2 of FIGS. 4 (a) and (b) and FIGS. 2 (a) and (b) is that in the cylindrical bearings 4-2 of FIGS. 4 (a) and 4 (b), The taper 4a is formed only at one end.

[0026]

[Fourth Embodiment] In the cylindrical bearing 4-3 of the fourth embodiment, the concavo-convex portion 20 as shown in FIG. 5 is also provided in the cylindrical bearing 4-2 of FIGS. 4 (a) and 4 (b). It has been deleted.

[0027]

[Fifth Embodiment] In the cylindrical bearing 4-4 shown in FIGS. 6 (a) and 6 (b) of the fourth embodiment, in the cylindrical bearing 4 shown in FIGS. 2 (a) and 2 (b), both bearings are supported. The taper 4a is not formed on the outer circumference of the portion 4b, and only the uneven portion 20 is formed on the outer circumference.

[0028]

[Effect of device]

 According to the present invention, in the process of mounting a cylindrical bearing and a cylindrical field magnet in the manufacture of a micro motor such as a cup-shaped coreless motor, the cylindrical field magnet is compressed without shrinking the inner diameter of the bearing portion of the cylindrical bearing. Since it can be press-fitted into the inner circumference of the magnet, it is possible to prevent defects and abnormal noises in micro motors such as cup-shaped coreless motors, shorten the manufacturing process of the micro motors, and reduce the cost. .

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a cup-shaped coreless motor according to a first embodiment of the present invention.

2A and 2B are a cross-sectional view and a side view showing a cylindrical bearing used in the cup-shaped coreless motor, respectively.

FIG. 3 is a sectional view showing a cylindrical bearing according to a second embodiment of the present invention.

4 (a) and 4 (b) are a sectional view and a side view, respectively, showing a cylindrical bearing of a third embodiment of the present invention.

FIG. 5 is a sectional view showing a cylindrical bearing according to a fourth embodiment of the present invention.

6 (a) and 6 (b) are a sectional view and a side view, respectively, showing a cylindrical bearing of a fifth embodiment of the present invention.

FIG. 7 is a vertical sectional view of a conventional cup-shaped coreless motor.

FIG. 8 is a cross-sectional view showing a method for mounting a cylindrical bearing and a cylindrical field magnet by a conventional cup-shaped coreless motor.

FIG. 9 is a cross-sectional view showing a method of attaching a cylindrical bearing and a cylindrical magnet by a conventional cup-shaped coreless motor.

FIG. 10 is a sectional view showing a method of fixing a cylindrical bearing and a cylindrical magnet by a conventional cup-shaped coreless motor.

[Explanation of symbols and symbols]

 M, M 'Cup type coreless motor 1 Cylindrical housing 1a Bearing holding part 2 Armature coil 3 Cylindrical magnet 4,4-1, ..., 4-4,4' Cylindrical bearing 4a Taper 4b Bearing Part 5 Rotating shaft 6 Locking boss 7 Liner 8 Commutator piece 9 Hub 10 Let ring 11 Brush stand 12 Brush 13 End cap 14-1 Positive side power supply lead wire 14-2 Negative side power supply lead Wire 15 Eccentric cam 16 Cylindrical coreless rotor 17 Press-fitting guide pin 17a Press-fitting guide pin Mandrel 17b Press-fitting guide pin plate 18 Press-fitting fixing jig 19 Press-fitting jig 20 Uneven portion

Claims (2)

[Scope of utility model registration request] 1. A bearing portion (4) projecting radially inward from both ends.
b) Cylindrical bearings (4, 4-1, ..., 4-4)
In a micromotor (M) in which a cylindrical field magnet (3) is press-fitted and fixed to the outer peripheral part of the bearing, when the bearing and the cylindrical field magnet (3) are relatively press-fitted, a through hole in a bearing portion of the bearing is provided. A micromotor characterized in that a shrinkage absorbing concave portion (4a, 20) for preventing the inside from shrinking in the inner peripheral direction is formed on the outer peripheral portion of the bearing. 2. The concave portion is formed by a knurled portion on the outer circumference of the bearing or an uneven portion (17) such as unevenness formed along the circumferential direction in the axial direction. The described micromotor.