JPH0519649U - Sintered oil-impregnated bearing - Google Patents

Abstract

(57) [Abstract] [Purpose] Sintered oil-impregnated bearings that can eliminate the aging that makes the rotary oil shaft fit in with the sintered oil-impregnated bearings, prolong the product life, and easily support thinner overall bearing structures. I will provide a. [Structure] In a sintered oil-impregnated bearing that rotatably supports a rotary shaft 1 to which lateral pressure is applied, a hard part 3b and a soft part 3a are axially joined. When lateral pressure is applied to the rotary shaft 1, the soft portion 3a
Quickly comes into surface contact with the rotating shaft 1 to form a familiar surface. The hard portion 3b prevents wear of the bearing and extends the life of the sintered oil-impregnated bearing.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a structure of a sintered oil-impregnated bearing that supports a rotary shaft that receives lateral pressure.

[0002]

[Prior Art]

 An example of a conventional sintered oil-impregnated bearing will be described with reference to the drawings. In FIG. 5 showing an example of a capstan motor, two sintered oil-impregnated bearings 23 made of a material such as iron, copper, or CCI (iron plated with copper and fired) are provided in the center hole of the bearing holder 24. , 23 are fitted and fixed vertically, and the rotary shaft 21 is rotatably supported by the sintered oil-impregnated bearings 23, 23. A stator core 25 is attached to the outer periphery of the bearing holder 24. The stator core 25 is configured by laminating a plurality of core elements, and has a plurality of salient poles in a radial pattern. A coil is wound around each salient pole of the stator core 25.

The upper part of the rotary shaft 21 protruding from the upper end of the bearing holder 24 is the output side, and the lower part is the non-output side. The output side of the rotary shaft 21 receives a lateral pressure load F by a pinch roller 28. A thrust washer 22 is fitted on the sintered oil-impregnated bearing 23 on the output side of the rotary shaft 21. A central hole portion of a rotor case 27 is fixed to the opposite output side of the rotary shaft 21, and a drive magnet 26 is attached to an inner surface of a peripheral wall of the rotor case 27. The inner peripheral surface of the drive magnet 26 faces the outer peripheral surface of the stator core 25 with a gap therebetween.

In the above configuration, when the rotary shaft 21 receives a lateral pressure load F on its output side by the pinch roller 28 or the like, the rotary shaft 21 bends and receives a force at one point of the sintered oil-impregnated bearing 23 to rotate. The contact portion between the shaft 21 and the sintered oil-impregnated bearing 23 becomes a line contact, and when the rotary shaft 21 further rotates, the contact portion between the rotary shaft 21 and the sintered oil-impregnated bearing 23 changes from a line contact to a surface contact. The clearance portion between 21 and the sintered oil-impregnated bearing 23 becomes a familiar surface through the oil due to the surface contact, and the current value of the motor decreases. Therefore, in order to quickly fit the sintered oil-impregnated bearing 23 and the rotary shaft 21, a taper (relief) is provided at the end of the center hole of the bearing holder 24 into which the sintered oil-impregnated bearing 23 is press-fitted.

[0005]

[Problems to be solved by the device]

 In the above-mentioned conventional sintered oil-impregnated bearing, if a material with a hard surface such as iron is used, the aging time until a familiar surface is made becomes considerably long, resulting in a high cost. On the other hand, if a material with a relatively soft surface hardness such as copper is used, the product life will be shortened although the aging time will not be required. Further, when CCI metal in which iron is plated with copper is used, the defects of iron and copper are compensated to some extent, but they are not completely compensated and aging is still required. Furthermore, whichever material is used, it is necessary to secure a certain span between the two sintered oil-impregnated bearings in order to ensure the accuracy of inclination of the rotating shaft, and it is difficult to make the bearing as a whole thinner. there were.

The present invention has been made in order to solve such a problem, and it is possible to eliminate the aging time until the sintered oil-impregnated bearing and the rotating shaft become compatible with each other, and to prolong the product life. It is an object of the present invention to provide a sintered oil-impregnated bearing which can easily be made thinner in the entire bearing structure.

[0007]

[Means for Solving the Problems]

 In order to achieve the above object, the present invention is a sintered oil-impregnated bearing in which a rotary shaft to which lateral pressure is applied is rotatably supported, in which a hard portion and a soft portion having different hardness are axially joined to each other. Is formed.

[0008]

[Action]

 When lateral pressure is applied to the rotary shaft, the soft part of the sintered oil-impregnated bearing quickly comes into surface contact with the rotary shaft to form a familiar surface. The hard part of the sintered oil-impregnated bearing prevents wear of the bearing and extends the life of the sintered oil-impregnated bearing.

[0009]

【Example】

 Embodiments of a sintered oil-impregnated bearing according to the present invention will be described below with reference to the drawings. In FIG. 1, the sintered oil-impregnated bearing 3 is fitted and fixed on the upper side and the sintered oil-impregnated bearing 6 is fitted on the lower side in the center hole of the bearing holder 5, and the rotary shaft 1 is rotated by the upper and lower sintered oil-impregnated bearings 3, 6. It is supported freely. A stator core (not shown) is attached to the outer peripheral portion of the bearing holder 5, and a predetermined stator set is configured as in the conventional example. The upper part of the rotary shaft 1 protruding from the upper end of the bearing holder 5 is the output side, and the lower part is the non-output side. The output side of the rotary shaft 1 receives a lateral pressure load F by a pinch roller or the like as shown in FIG. A thrust washer 2 is fitted on the sintered oil-impregnated bearing 3 on the output side of the rotary shaft 1. The center hole of the rotor assembly 7 is fitted and fixed to the counter output side of the rotary shaft 1. A motor is composed of the stator core and the rotor set 7. However, the structure of the motor is not directly related to the present invention, and the description of the motor is omitted.

The sintered oil-impregnated bearing 3 that supports the output side of the rotary shaft 1 is configured by combining two sintered oil-impregnated bearings having different hardnesses, and the soft portion 3a is the side that receives the acting force of the rotary shaft 1 strongly. The other side is composed of the hard portion 3b. As shown in FIG. 2, when the rotary shaft 1 receives a lateral pressure load F from a certain direction on its output side, the soft portion 3a has a surface contact shape 8 whose contact point with the rotary shaft 1 becomes a familiar surface due to wear. In order to facilitate the formation of the metal, a material having a relatively soft hardness, for example, a copper-based material is used. On the other hand, the hard portion 3b is formed using a material having a relatively high hardness, for example, an iron-based material, in order to prevent wear and prolong the life.

Since a large lateral pressure load is not applied to the counter-output side of the rotary shaft 1, the sintered oil-impregnated bearing 6 supporting the counter-output side of the rotary shaft 1 does not necessarily have the same hardness as the sintered oil-impregnated bearing 3 on the output side. It is not necessary to form the hard part and the soft part by joining them in the axial direction, and either a hard material or a soft material may be used. However, when a large lateral pressure load is also applied to the counter output side of the rotary shaft 1, the sintered oil-impregnated bearing 6 also has a hard portion and a soft portion, which have different hardnesses, joined together in the axial direction, and the counter output side has the soft portion and the output side. May be a hard part.

As described above, by using the soft portion 3a and the hard portion 3b having different hardness in combination as the sintered oil-impregnated bearing 3, the surface contact shape 8 shown in FIG. 2 is quickly formed on the soft portion 3a. Therefore, aging can be eliminated, and unnecessary wear other than forming the surface contact shape 8 can be eliminated by the hard portion 3b of the sintered oil-impregnated bearing 3, so that the sintered oil-impregnated bearing 3 has It becomes possible to extend the life. Further, by providing a hard portion 3b on a part of the sintered oil-impregnated bearing 3 to prevent unnecessary wear, even if the span of the output oil-side sintered oil-impregnated bearing 3.6 is shortened, The inclination accuracy of 1 can be maintained at a high level, and the entire bearing can be made thinner.

As shown in FIG. 3, when the length in the axial direction of the soft portion 3a constituting the sintered oil-impregnated bearing 3 is A and the length in the axial direction of the hard portion 3b is B, A and B The ratio of is the magnitude of the lateral pressure load F, the distance 1 from the sintered oil-impregnated bearing 3 on the output side of the rotating shaft 1 to the position where the lateral pressure load F is received, the sintered oil-impregnated bearing 3 on the output side and the opposite output side It is set based on the distance (span) L from the oil-impregnated bearing 6. That is, when the lateral pressure load F applied to the rotary shaft 1 is large or the distance 1 on the output side of the rotary shaft 1 is long, the length B of the hard portion 3b is set large to prevent wear.

As a combination of the materials of the soft part 3a and the hard part 3b of the sintered oil-impregnated bearing 3 in the above embodiment, copper and iron, CCI and iron, copper and CCI, etc. can be considered.

The soft portion 3a and the hard portion 3b of the sintered oil-impregnated bearing 3 in the above-described embodiment are sintered oil-impregnated bearings that are separately fired with their respective materials, and these bearings are fitted to the bearing holder 5 in a layered manner. Although fixed, the sintered oil-impregnated bearing may be produced by integrally firing the soft portion and the hard portion. FIG. 4 shows an embodiment of such a sintered oil-impregnated bearing. By combining a soft material forming the soft part 10 and a hard material forming the hard part 9 and firing them at the same time, This is a sintered oil-impregnated bearing in which the portion 10 and the hard portion 9 are continuously and integrally formed. In that case, there are copper and iron, CCI and iron, copper and CCI, etc. as the material combination of the soft portion 10 and the hard portion 9.

[0016]

[Effect of the device]

 According to the present invention, by using a soft portion and a hard portion having different hardness in combination as a sintered oil-impregnated bearing, it is possible to quickly form a surface contact portion with the rotating shaft in the soft portion, so that aging is prevented. It is possible to abolish it, and since unnecessary wear other than the part that forms the surface contact shape can be eliminated by the hard part of the sintered oil-impregnated bearing, the life of the sintered oil-impregnated bearing can be extended. ..

Further, since a hard portion can be provided in a part of the sintered oil-impregnated bearing to prevent unnecessary wear, when the rotary shaft is supported between the two sintered oil-impregnated bearings, two sintered oil-impregnated bearings are used. Even if the span of the bearing is shortened, the inclination accuracy of the rotating shaft can be kept high, which makes it possible to reduce the overall thickness of the bearing.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a sintered oil-impregnated bearing according to the present invention.

FIG. 2 is a cross-sectional view showing the operation of the main part of the above embodiment.

FIG. 3 is a sectional view showing an arrangement relationship of main parts of the embodiment.

FIG. 4 is a sectional view showing a main part of another embodiment of the sintered oil-impregnated bearing according to the present invention.

FIG. 5 is a sectional view showing an example of a conventional oil-impregnated sintered bearing.

[Explanation of symbols]

 1 rotary shaft 3 sintered oil-impregnated bearing 3a soft part 3b hard part

Claims (1)

[Scope of utility model registration request] 1. A sintered oil-impregnated bearing which rotatably supports a rotary shaft to which lateral pressure is applied, characterized in that a hard portion and a soft portion having different hardnesses are axially joined to each other.