JP3218795B2 - Motor bearing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor bearing device used for, for example, audio, video equipment, office equipment, industrial equipment, and the like.

[0002]

2. Description of the Related Art In recent years, with the expansion of the home and industrial markets, demand for light, thin, short and long-life motors has increased, and the development of ultra-compact, high-performance motors has been desired.

This motor will be described with reference to FIG. 6 using a brushless DC motor as an example. In FIG. 6, reference numeral 11 denotes a rotor shaft, which is a rotor frame 13 to which a cylindrical magnet 12 having N and S poles alternately magnetized in the circumferential direction is fixed.
To form a rotor. Reference numeral 14 denotes a ball bearing, and reference numeral 15 denotes a sintered oil-impregnated metal, which is fixed to a metal bearing housing 17 fixed near the center of a substrate 16 on which circuit elements necessary for driving and controlling the motor are mounted. A stator core 18 is arranged around the bearing housing 17, and a coil 19 wired on the substrate 16 is wound around to form a stator. The rotor shaft 11 is inserted into the inner diameter of the ball bearing 14 and the sintered oil-impregnated metal 15 so as to rotatably support the rotor, thereby constituting a brushless DC motor.

The operation of the thus configured motor bearing device will be described below.

First, when the coil 19 is energized, the rotor is rotated by magnetic attraction and repulsion with the magnet 12 fixed to the rotor. The rotor is composed of the magnet 12 and the substrate 16
The magnetic attraction force presses the rotor frame 13 against the bearing 14 to prevent thrust vibration and movement. The rotor is rotatably supported by a bearing 14 and a sintered oil-impregnated metal 15 in a radial direction rotation X generated by the rotation and a thrust direction load Y generated by a magnetic attraction force of the magnet 12 and the substrate 16.

[0006]

However, in the above-mentioned conventional configuration, when the motor is further reduced in size and weight,
The bearing span for supporting the rotor in the radial direction becomes short, and the performance required for the motor such as shaft runout cannot be satisfied. Further, the space of the bearing housing for holding the bearing portion hinders miniaturization.

The present invention solves the above-mentioned conventional problems. The bearing housing and the ball bearing are eliminated, the radial and thrust loads of the rotor are rotatably supported by the rotor shaft itself, and shaft runout and the like are reduced. An object of the present invention is to provide a motor bearing device that realizes a light, thin and small motor that satisfies performance.

[0008]

In order to achieve the above object, a rotor shaft of a bearing device for a motor according to the present invention is fitted inside a fixed shaft fixed to a substrate so as to support a rotating rotor. It has a hole, and further has a thrust support plane so that it can support a load in the thrust direction,
The cutout is provided so that the fitting hole and the thrust support plane can be machined.

[0009]

With this configuration, the radial load of the motor rotation is supported by the fitting hole of the rotor shaft and the outer diameter of the fixed shaft, and the load in the thrust direction is supported by the thrust support plane and the tip of the fixed shaft. In addition, the rotor can be rotatably supported without using a bearing housing or a ball bearing that hinders lightness and size. further,
By providing the notch for processing, the rotational accuracy of the rotor can be improved.

[0010]

(Embodiment 1) An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, 1 is a rotor shaft, 2 is a fixed shaft, 3 is a substrate, and 4 is a boss for fixing the fixed shaft.

The operation of the motor bearing device configured as described above will be described. First, the fixed shaft 2 is fixed to the boss 4, and the boss 4 is fixed to the substrate 3. The rotor shaft 1 has a fitting hole. The fixed shaft 2 is inserted into the fitting hole so that a load in a radial direction when the rotor shaft 1 rotates can be rotatably supported. Further, a thrust support plane is provided on a portion of the rotor shaft 1 which is in contact with an end face of the fixed shaft 2 so as to support a load in the thrust direction. Is provided with a notch at the outer diameter. Since the notch portion is provided in the outer diameter portion of the rotor shaft 1, not only the inner diameter size and the inner diameter roundness of the fitting hole can be processed with high accuracy, but also the flatness and surface of the thrust support plane. Roughness and the like can be processed with high precision.

As described above, according to this embodiment, the rotor shaft has the fitting hole and the thrust support plane, and further has the fitting hole and the notch for processing the thrust support plane, and is fixed to the substrate. The rotor shaft can be rotatably supported by the fixed shaft fixed to the boss, so that the weight and thickness can be reduced without using a bearing housing and ball bearing that hinder the reduction in size and weight. Therefore, the rotation of the rotor shaft can be supported with high accuracy.

(Embodiment 2) A second embodiment of the present invention will be described below with reference to the drawings.

In FIG. 2, 1 is a rotor shaft, 2 is a fixed shaft, 3 is a substrate, and 4 is a boss for fixing the fixed shaft. The above is the same as the configuration in FIG. FIG.
Is different from that of the first embodiment in that a hollow cylindrical sintered oil-impregnated metal 6 in which the inner diameter of the fitting hole of the rotor shaft 1 is
Is pressed or sintered integrally.

The operation of the motor bearing device configured as described above will be described below.

As described above, the hollow cylindrical sintered oil-impregnated metal 6 impregnated with the lubricant is press-fitted or integrally sintered into the inner diameter portion of the fitting hole of the rotor shaft 1, so that the rotor shaft 1 is actuated by the action of the lubricant. The wear of the rotor shaft 1 and the fixed shaft 2 caused by the rotation of the rotor 1 can be suppressed.

As described above, according to this embodiment, a hollow cylindrical sintered oil-impregnated metal impregnated with a lubricant is press-fitted or integrally molded into the inner diameter portion of the rotor shaft. It is possible to provide a motor bearing device that can suppress wear due to sliding and realize light, thin, short, and long life.

Embodiment 3 Hereinafter, a third embodiment of the present invention will be described with reference to the drawings.

In FIG. 3, 1 is a rotor shaft, 2 is a fixed shaft, 3 is a substrate, and 4 is a boss for fixing the fixed shaft. The above is the same as the configuration in FIG. FIG.
The difference from the above configuration is that the rotor shaft 1 is made of a sintered oil-impregnated metal impregnated with a lubricant.

The operation of the motor bearing device configured as described above will be described below. Rotor shaft 1
Is made of a sintered oil-impregnated metal impregnated with a lubricant, it is possible to suppress not only wear due to sliding in the radial direction but also wear on the thrust support plane.

As described above, according to this embodiment, since the rotor shaft is made of a sintered oil-impregnated metal impregnated with a lubricant, it is possible to suppress wear due to sliding in the radial and thrust directions, and to reduce the size and weight of the rotor. , Long life can be realized.

(Embodiment 4) Hereinafter, a fourth embodiment of the present invention will be described with reference to the drawings.

In FIG. 4, 1 is a rotor shaft, 2 is a fixed shaft, 3 is a substrate, and 4 is a boss for fixing the fixed shaft. The above is the same as the configuration in FIG. FIG.
The difference from the above configuration is that the fixed shaft 2 is coated with a resin.

The operation of the motor bearing device configured as described above will be described below. Since the fixed shaft 2 is coated with a self-lubricating and highly sliding resin such as a fluororesin, a polyamide resin, and a polyacetal resin, it is possible to suppress abrasion due to sliding without using a lubricant.

As described above, according to the present embodiment, abrasion due to sliding can be suppressed by coating the fixed shaft with a self-lubricating resin having good sliding properties. Can be realized.

(Embodiment 5) Hereinafter, a fifth embodiment of the present invention will be described with reference to the drawings.

In FIG. 5, 1 is a rotor shaft, 2 is a fixed shaft, 3 is a substrate, and 4 is a boss for fixing the fixed shaft. The above is the same as the configuration in FIG. FIG.
The difference from the above configuration is that the fixed shaft 2 is coated with ceramic.

The operation of the motor bearing device configured as described above will be described below. By coating the fixed shaft 2 with a ceramic of high hardness, a difference in hardness from the rotor shaft 1 is provided, and wear due to sliding can be suppressed.

As described above, according to the present embodiment, by coating the fixed shaft with a ceramic having high hardness, abrasion due to sliding can be suppressed, and light, thin, short and long life can be realized.

The fixed shaft may be directly fixed to the substrate. In this case, since the fixed shaft can be fixed without using a boss for fixing the fixed shaft, the number of parts can be further reduced, and the rotation of the rotor shaft can be supported.

In the case of the fourth and fifth embodiments, a lubricant may be used. In this case, a longer life can be realized as compared with the case where no lubricant is used.

In the case of the fourth and fifth embodiments, the coating may be performed on the inner diameter of the rotor shaft.

[0034]

As described above, the present invention has a fitting hole and a thrust support plane inside a rotor shaft so that a rotor that directly rotates can be supported by a fixed shaft fixed to a substrate. An excellent motor that can rotatably support a rotor without using a bearing housing and a ball bearing that hinder miniaturization by forming a cutout portion on the outer surface of the rotor shaft that can form a fitting hole. The bearing device can be realized.

[Brief description of the drawings]

FIG. 1 is a sectional view of a motor bearing device according to a first embodiment of the present invention.

FIG. 2 is a sectional view of a motor bearing device according to a second embodiment of the present invention;

FIG. 3 is a sectional view of a bearing device for a motor according to a third embodiment of the present invention.

FIG. 4 is a sectional view of a bearing device for a motor according to a fourth embodiment of the present invention.

FIG. 5 is a sectional view of a bearing device for a motor according to a fifth embodiment of the present invention.

FIG. 6 is a cross-sectional view of a brushless DC motor having a conventional motor bearing device.

[Explanation of symbols]

 1,11 rotor shaft 2 fixed shaft 3,16 substrate 4 boss 6,15 sintered oil-impregnated metal 12 magnet 13 rotor frame 14 ball bearing 17 bearing housing 18 stator core 19 coil X radial rotation Y thrust load

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁷ , DB name) H02K 5/167 F16C 17/10 F16C 33/08 F16C 33/10

Claims (7)

(57) [Claims] 1. A motor bearing device comprising a rotor shaft connected to a rotating rotor and a fixed shaft rotatably supporting the rotor shaft, wherein the rotor shaft has a fitting hole and a thrust support plane portion therein. A bearing device for a motor, comprising a notch and a notch. 2. A motor bearing according to claim 1, wherein a hollow cylindrical sintered oil-impregnated metal impregnated with a lubricant is press-fitted or integrally sintered into an inner diameter portion of said fitting hole of said rotor shaft. apparatus. 3. The motor bearing device according to claim 1, wherein said rotor shaft is made of a sintered oil-impregnated metal impregnated with a lubricant. 4. The lubricant according to claim 1, wherein said lubricant is composed of mineral oil or synthetic oil, grease containing said mineral oil or synthetic oil as a main component, or liquid paraffin. 4. The bearing device for a motor according to 2 or 3. 5. The motor bearing device according to claim 1, wherein said fixed shaft is coated with a resin. 6. The motor bearing device according to claim 5, wherein said resin is made of a fluorine resin, a polyamide resin, or a polyacetal resin. 7. The motor bearing device according to claim 1, wherein said fixed shaft is coated with ceramic.