JPH0623173Y2 - Motor bearing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a bearing device for a motor, and more particularly to an improvement of the bearing device suitable for use in a brushless motor of a plane-opposing type.

(B) Conventional Technology Conventionally, for example, in a plane opposed type brush motor, as shown in FIG. 3, a hollow portion 3 of a cylindrical bearing casing 1 is used.
An oilless metal 7 and a ball bearing 5 are coaxially fixed therein as a bearing member, a stator yoke 11 is attached to a flange 9 formed on the outer circumference of the bearing casing 1, and a circuit pattern formed on the stake yoke 11 (not shown). ), A plurality of drive coils 13 are annularly attached to form a stator 14, and a rotor yoke 17 having a main magnet 15 facing the drive coils 13 is attached to a rotating shaft 21 via a bush 19 to form a rotor 22. And the rotary shaft 21 is inserted through the ball bearing 5 and the oilless metal 7 from the ball bearing 5 side so as to be rotatably supported.

The brushless motor having such a structure is used in the stator yoke.
Since an attractive force acts between 11 and the main magnet 15, if the push 19 contacts the inner ring 23 of the ball bearing 5 and the position of the rotary shaft 21 in the thrust direction is regulated,
A preload is generated in the ball bearing 5 by the attraction force to ensure the smooth rotation of the ball bearing 5, and the rotor 22 rotates with the space between the drive coil 13 and the main magnet 15 kept at a predetermined dimension. .

(C) Problems to be solved by the invention However, when such a motor is used as a capstan motor, a pinch roller abuts on the tip end side of the rotary shaft 21 protruding from the bearing casing 1 side, and the rotary shaft is rotated.
Since force is applied to 21, the oilless metal 7 may be easily worn.

Since the oilless metal 7 is generally made by impregnating a relatively porous metal material with oil, the oilless metal 7 is worn faster than the ball bearing 5 by the force applied to the rotating shaft 21.

Of course, if the rotary shaft 21 is supported by two ball bearings, it is possible to suppress the rapid wear of the bearing member, but since the ball bearing 5 is relatively expensive as compared with the oilless metal 7, It is often practiced to use oilless metal 7 on either side.

Further, even if the structure using the oilless metal 7 and the ball bearing 5 is used, the tip side of the rotating shaft 21 may be the ball bearing 5, but in that structure, the rotating shaft 21 is used.
It is difficult to control the position of the thrust bearing 21 and a mechanism for applying a preload to the ball bearing 5 is required.

In order to solve such a drawback, a configuration as shown in FIG. 4 has also been proposed (see Japanese Utility Model Laid-Open No. 59-127918).

That is, the ball bearing 5 is used on the tip side of the rotary shaft 21, and the notch 25 is formed on the outer periphery of the rotary shaft 21 between the oilless metal 7 and the ball bearing 5 so as to contact the inner ring 23 of the ball bearing 5. The engaging member 27 that fits into the cutout portion 25 is fitted to the rotating shaft 21, and the engaging member 27 that abuts the inner ring 23 of the ball bearing 5 causes the rotating shaft 21 to rotate.
The position is regulated in the thrust direction and the ball bearing 5 is preloaded.

The present invention has been made under the above-mentioned circumstances, and not the structure using the engaging member as the stopper as shown in FIG. 4 but a completely different structure for restricting the position of the rotary shaft in the thrust direction and for the ball bearing. A bearing device for a motor having a configuration for generating a preload.

(D) Means for Solving the Problems In order to solve the above-mentioned problems, the present invention provides an oilless metal 7 and a ball in the hollow portion 3 of the bearing casing 1 as shown in FIGS. 1 and 2. The bearings 5 are coaxially fixed at intervals, and the rotary shaft 21 to which the rotor yoke 17 having the main magnet 15 is attached is inserted from the oilless metal 7 side so as to be freely rotatable on the oilless metal 7 and the ball bearing 5. A supporting portion 35 is formed on the rotating shaft 21 in the vicinity of the oilless metal 7 and the ball bearing 5 so as to support the position regulating member 39 on the supporting portion 35, and a hollow portion is formed from the outer circumference of the bearing casing 1. The insertion hole 37 communicating with the portion 3 is formed on the same plane as the holding portion 35.

(E) Action In the present invention having such means, when the rotor yoke 17 is attracted toward the main magnet 15 and the rotary shaft 21 receives a force in the thrust direction, the position regulating member 39 causes the ball bearing 5 to move.
The position of the rotary shaft 21 is restrained by abutting against the inner end face of the rotary shaft 21 so that the rotary shaft 21 is prevented from moving in the thrust direction.
A preload is generated in the ball bearing 5 due to the contact of.

(F) Example An example of the present invention will be described below. The same parts as those in the conventional example are designated by the same reference numerals.

FIG. 1 is a half sectional view showing an embodiment of a bearing device for a motor according to the present invention together with a brushless motor.

An oilless metal 7 and a ball bearing 5 are coaxially fixed to both ends of the hollow portion 3 of the tubular bearing casing 1.

On the flange 9 formed on the outer circumference of the oilless metal 7,
The stator yoke 11 is fixed so as to be placed thereon, and a circuit pattern (not shown) is formed on the upper side of the stator yoke 11 via an insulating layer.

A plurality of drive coils 13 formed by winding a conductive wire in a small frame shape are mounted on the stator yoke 11 so as to surround the bearing casing 1 and connected to a circuit pattern.
Are formed.

A cup-shaped rotor yoke 17 having an annular main magnet 15 fixed to the drive coil 13 is attached to a ring-shaped bush 19
The rotor 22 is formed by being fixed to one (upper) end of the rotary shaft 21 via.

On the outside of the side wall 29 of the rotor yoke 17, for example, a magnet for frequency power generation 31 that is magnetized with about 1000 poles is attached. The conversion element 33 is connected and fixed to the circuit pattern of the rotor yoke 17 so as to face the frequency power generation magnet 31.

The rotating shaft 21 of the stator 14 is inserted into the oilless metal 7 and the ball bearing 5 from the oilless metal 7 side, and is rotatably supported by these.

The rotating shaft 21 is, as shown in FIG.
Between the ball bearing 5 and the ball bearing 5
An insertion hole 35 penetrating in the lateral direction is formed in the vicinity of.

An insertion hole 37 is formed in the bearing casing 1 from the outer periphery toward the hollow portion 3 at a position horizontal to the insertion hole 35,
From the insertion hole 37 to the position regulating pin 39 such as a spring pin.
Is inserted into and held in the insertion hole 35 of the rotary shaft 21.

The position restricting pin 39 has a length that contacts only the inner ring 23 of the ball bearing 5, and contacts the inner ring 23 to restrict the movement of the rotary shaft 21 in the thrust direction.

In the brushless motor configured as described above, the position regulating pin 39 fixed to the rotating shaft 21 by the attractive force between the stator yoke 11 and the main magnet 15 contacts the inner ring 23 of the ball bearing 5 to prevent the rotating shaft 21 from moving in the thrust direction. The movement is restricted in position, and the ball bearing 5 is preloaded.

In the present invention, the position regulating pin 39 is the ball bearing 5
Although it has a function of restraining the movement of the rotary shaft 21 in the thrust direction by abutting against the inner ring 23 of the present invention, in the present invention, in addition to the position regulating pin 39, for example, a C ring fitted in a groove formed on the outer periphery of the rotary shaft 21 is used. The object of the present invention can be achieved even by using a position regulating member, and a holding portion for holding the position regulating member may be formed on the rotary shaft 21, and the position regulating member can be inserted into the bearing casing. The holes may be formed.

(G) Effect of the Invention As described above, the present invention provides the oilless metal 7 and the ball bearing 5 fixed to the bearing casing 1,
The rotary shaft 21 is inserted from the oilless metal 7 side to be rotatably supported, and a holding portion such as an insertion hole 35 is formed on the rotary shaft 21 between the oilless metal 7 and the ball bearing 5 in the vicinity of the ball bearing 5. Since the position regulating member 39 is inserted into the insertion hole 33 from the insertion hole 37 formed in the bearing casing 1 and held so as to be able to contact the inner ring 23 of the ball bearing 5, the rotor yoke 17 is attracted toward the main magnet 15. The position regulating member 39 comes into contact with the inner ring 23 of the ball bearing 5 to regulate the position, the movement of the rotary shaft 21 in the thrust direction is suppressed, and the ball bearing 5 is preloaded.

Therefore, the distance between the rotor 22 and the stator 14 is maintained in an accurate positional relationship, and smooth rotation of the rotor 22 is ensured.

Further, since it can be expected that the position regulating member of the present invention is less deformed by temperature change than the stopper member of the bearing device of FIG. 4 described above, the reliability is good against temperature change. is there.

[Brief description of drawings]

FIG. 1 is a half sectional view showing an embodiment of a bearing device for a motor according to the present invention together with a brushless motor, FIG. 2 is an enlarged partial sectional view for explaining an essential part of the present invention, and FIGS. 3 and 4 are It is a half cross-sectional view explaining a conventional bearing device for a motor together with a brushless motor. 1 ... Bearing casing, 3 ... Hollow part, 5 ... Ball bearing, 7 ... Oilless metal, 11 ... Stator yoke, 13 ... Drive coil, 14 ... Stator, 15 ... Main magnet, 17 ... … Rotor yoke, 21 …… Rotating shaft, 22 ……
Rotor, 23 ... Inner ring, 27 ... Engaging member, 35 ... Holding part (insertion hole), 37 ... Insert hole, 39 ... Position regulating member (position regulating pin).

Claims (1)

[Scope of utility model registration request] 1. A bearing casing, an oilless metal and a ball bearing coaxially fixed to a hollow portion of the bearing casing at a distance from each other, a rotor yoke having a main magnet, and the oilless metal side. A rotary shaft that is inserted between the oilless metal and the ball bearing and is supported by a holding portion formed between the oilless metal and the ball bearing in the vicinity of the ball bearing near the ball bearing. A position restricting member that abuts only on the inner ring of the rotating shaft and restricts the position of the rotating shaft; A bearing device for a motor, comprising: an insertion hole.