JPH0552347U - Sintered bearing - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To provide a plain bearing having a thrust bearing for receiving a shaft end face at one end of a shaft hole of a radial bearing, which is easy to manufacture and has good bearing performance. [Construction] In a sintered bearing 1, a radial bearing portion 2 and a thrust bearing portion 3 are integrally formed of a sintered alloy, and a region of the radial shaft hole adjacent to the thrust bearing forms a larger diameter portion 4 than the diameter of the radial bearing shaft hole. is doing.

Description

[Detailed description of the device]

[0001]

[Industrial application]

 The present invention relates to a structure of a sintered bearing, which is used as a bearing including a radial bearing and a thrust bearing, such as a bearing for a flat motor.

[0002]

[Prior Art]

 As shown in FIG. 6, one end of the shaft 11 is thrust-supported and the other end is provided with a rotary disk 12 such as a magnetic rotor or a pulley. It is known that two radial bearings 1 are mounted separately on a fixed housing 15 and a thrust receiving member 3b such as resin or heat treated steel is fixed.

[0003]

[Problems to be solved by the device]

 Such a bearing element is composed of the housing 15, the radial bearing 1, and the thrust receiving member 3b. Since each of them is manufactured and assembled, it takes a lot of time and labor and the cost is high. Therefore, an object of the present invention is to provide a bearing element including a radial bearing and a thrust bearing which are easy to manufacture and have good bearing performance.

[0004]

[Means for Solving the Problems]

 In order to achieve the object, according to the present invention, the radial bearing portion and the thrust bearing portion are integrally formed of sintered alloy, and the area of the radial bearing shaft hole adjacent to the thrust bearing is made larger than the radial bearing shaft hole diameter. It is characterized by being formed. In addition, the vicinity of the bearing surface of the thrust bearing portion is characterized by forming fewer pores than other portions.

In the above means, the shaft hole of the radial bearing can be formed in a plain state, or can be provided at two positions separated from the opening and the large diameter part. The large-diameter portion formed in the area of the axial hole of the radial bearing adjacent to the thrust bearing may be about 5 to 50 μm larger than the diameter of the axial hole, although it depends on the size of the bearing. The thrust bearing portion can be formed in a flat surface or a spherical surface. Further, the amount of pores on this bearing surface can be formed smaller than that of other portions. In this case, the thrust bearing surface is made of a sintered material, but a thrust receiving member such as steel may be inserted from the shaft hole and fixed to the thrust receiving portion.

The bearing can be manufactured by powder molding, sintering, sizing and, if necessary, impregnating oil as in the case of a normal sintered bearing. For the large diameter part, when preparing a cup-shaped sintered body in which one side of the cylinder is closed and sizing, the part that forms the shaft hole is narrowed from the outer diameter side or the part that forms the shaft hole. Can be formed by expanding the cylinder that is compressed in the axial direction and becomes a large diameter portion while constraining.

[0007]

[Action]

 Therefore, the housing and the bearings can be integrally made of a sintered alloy, and can be efficiently manufactured. When used with oil, the bearing element has a large oil content, which prolongs the service life of the bearing. The large diameter part of the axial hole adjacent to the thrust bearing of the radial bearing forms a gap with the shaft, and when the shaft is tilted, strong sliding contact with the shaft end is eliminated, and rotation becomes lighter. In addition, the gap has an effect as an oil chamber, so that the rotation becomes smoother.

By coining the thrust receiving surface of the sintered bearing to reduce the amount of pores, the strength of the oil film in the bearing can be increased and the rotation becomes smooth. Further, if the thrust receiving surface is formed in a spherical shape, the inclination of the shaft can be alleviated. The entire radial bearing except for the large diameter part may be used as the bearing surface, but when operating under a light load, the bearing surface should be separated from the opening and the large diameter part. By reducing the bearing area, the rotational resistance of the shaft can be reduced.

[0009]

【Example】

 Hereinafter, the configuration of the present invention will be described based on the embodiment shown in the drawings. 4 and 5 show a method of manufacturing a sintered bearing with a flange. FIG. 4A is a cross-sectional view of the sintered body, which has a substantially cup shape with a blind hole having a diameter slightly larger than the inner diameter of the bearing. This is because projections 5 are provided on the bottom of the cup hole and on the back surface of the bottom so as to increase the density by pressing during the subsequent sizing. As the sintered body, an iron-based material in which graphite is dispersed, a bronze-based material in which molybdenum disulfide particles are dispersed, an aluminum alloy-based material, or the like can be appropriately adopted.

FIG. 4B shows a compressed state of sizing. The die 21 substantially corresponds to the outer shape of the sintered body, but has a narrowed portion 21a. When the sintered bearing 1 is pushed into the die 1 by the upper punch 24 and the lower punch 23 and the core 22 are supported from below, the core 22 is gripped by contracting inside the narrowed portion 21a from the end face of the cylindrical portion, and the inner diameter is It is sized to form a shaft hole. The cylindrical part close to the cup bottom is not constricted and forms a large diameter part. Further, the protrusions 5 are compressed by the upper punch 24 and the core 22, and the density in the vicinity of the protrusions 5 becomes higher than the other portions. Then, the mold is released.

FIG. 5 shows a case where a radial bearing surface is separated into two places, and a sintered bearing is formed in which an intermediate portion thereof forms a large gap with the rotating shaft. FIG. 5A shows a sintered body in which a step is provided on the outer diameter of the cylindrical portion. The protrusion 5 is provided on the bottom of the cup. The B zone and the D zone of the cylindrical portion are narrowed, and the A zone and the C zone are the large diameter portion. FIG. 5B shows the sizing state, which is different from FIG. 4 in that the die 21 has two narrowed portions 21a and the end surface of the core 22 is a spherical portion 3a.

In both FIG. 4B and FIG. 5B, the large diameter portion 4 and the gap 6 are exaggerated. In order to form the large-diameter portion 4, the outer diameter of the portion to be the large-diameter portion is set in the same manner as described above, and the portion is expanded outward by compressing from the axial direction. You can FIG. 1 is a cross-sectional view schematically showing a state in which a sintered bearing is caulked and bonded to a substrate 14 such as a chassis, and a shaft 11 having a rotating disk 12 is mounted. The large-diameter portion 4 and the like are exaggerated. When the rotary disk 12 is a pulley, the shaft is slightly inclined by the tensile force of the belt, but since the bearing 1 has the large diameter portion 4, the bearing is not damaged by the vicinity of the shaft end. Normally, the oil is used by being impregnated with oil, but the gap between the large-diameter portion 4 and the shaft 11 serves as an oil sump, so that the thrust bearing portion 3 that receives an axial load can be efficiently oiled. When the amount of pores on the surface or deep part of the thrust bearing 3 is reduced, the oil pressure on the bearing surface is less likely to escape into the pores of the sintered material, and the oil film strength is increased. The coefficient of friction is lowered together with the refueling.

FIG. 2 shows an example in which the end of the shaft 11 is spherical and the thrust receiving surface of the bearing is also spherical. In this case, the tilting force of the shaft 11 is received by the spherical portion 3a, and the gap between the large diameter portion 4 and the shaft acts as an oil sump. FIG. 3 shows an example in which a thrust receiving member 3b, which is a resin plate or a hardened steel plate whose surface is polished, is attached to the thrust receiving portion of the bearing. The thrust receiving member 3b has a diameter smaller than the diameter of the shaft hole of the radial bearing, and is made by inserting it into the bottom, pressing it with a punch, and embedding it to the predetermined depth of the sintered bearing. Suitable for applications with large thrust load.

[0014]

[Effect of the device]

 As described above, the sintered bearing of the present invention has a long bearing life because the amount of oil can be increased, and a gap is provided between the end of the shaft and the bearing to efficiently store oil on the thrust bearing surface as an oil reservoir. Since it can be refueled, it has less thrust friction and wear, and also has the economical effect of simplifying the manufacturing of bearing elements.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an embodiment of use of the sintered bearing of the present invention.

FIG. 2 is a sectional view showing an embodiment of a sintered bearing of the present invention.

FIG. 3 is a sectional view showing an embodiment of the sintered bearing of the present invention.

FIG. 4 is a cross-sectional view showing a method for manufacturing a sintered bearing of the present invention.

FIG. 5 is a cross-sectional view showing a method of manufacturing a sintered shaft according to the present invention.

FIG. 6 is a cross-sectional view showing the structure of a conventional bearing element.

[Explanation of symbols]

 1 Sintered bearing 2 Radial bearing part 3 Thrust bearing part 4 Large diameter part

Claims (2)

[Scope of utility model registration request] 1. A plain bearing having a thrust bearing for receiving a shaft end surface at one end of a shaft hole of the radial bearing, wherein the radial bearing portion and the thrust bearing portion are integrally formed of a sintered alloy,
A sintered bearing characterized in that the area adjacent to the thrust bearing of the radial shaft hole is formed to have a diameter larger than the diameter of the shaft hole of the radial bearing. 2. The sintered bearing according to claim 1, wherein the thrust bearing has fewer pores near the bearing surface than other portions.