JPH0464712A - Oil-impregnated bearing - Google Patents

Abstract

PURPOSE:To obtain good lubrication from a start of use, and improve the efficiency and a liftime of a bearing by providing a positioning part for locating a non-porous part on a part of the bearing surface where a rotating shaft, which is supported by the bearing consisting of a porous part and a non-porous part, is come in pressure-contact with a load. CONSTITUTION:An inner surface 20a of a porous part 20 made of Cu group sintered material and a non-porous surface 30a form a bearing surface 50 for supporting a rotating shaft 40, and a projecting part 21 is formed in a centaral part of the inner surface 20a with tapers from both ends 20b, 20c. The non- porous part 30 made of white metal is located in the inner surface 20a side, and a projecting part 31 is provided in the surface 30 with tapers from both ends toward a central part to form a surface 30a into curvature as same as the inner surface 20a so as to form a part of the bearing surface 50. Consequently, an oil film having a high intensity is formed in a part to be pushed, and good lubirication is obtained, and a coefficient of friction is reduced to improve the efficiency, and a lifetime can be prolonged.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to oil-impregnated bearings (oiles metal), in particular:
It is suitable for use in small motors for automobiles, etc., where it is difficult to supply oil to the bearings, and aims to improve the efficiency and extend the life of oil-impregnated bearings.

Conventional technology Conventionally, small motors for automobiles, especially wiper motors, etc., use a worm reduction mechanism in which a worm gear is integrated or connected to the motor output shaft and meshes with the worm wheel to transmit rotational force. The bearing for the output shaft is required to have high surface load resistance and high efficiency, and for this reason ball bearings have generally been used.

However, ball bearings have problems in terms of cost and noise, so oil-impregnated bearings (oilless metal) have come to be used, but oil-impregnated bearings have the problem of being inferior to ball bearings in terms of efficiency and lifespan. there were.

Therefore, in oil-impregnated bearings, a proposal was made to improve efficiency by reducing the friction coefficient by reducing the contact area with the rotating shaft.
1-70624), and a proposal to reduce the amount of wear and extend the life by arranging a bearing member with low porosity so as to wrap a segment-shaped bearing member with high porosity (see Japanese Patent Publication No. 35-13253). It has been accomplished.

However, all of the previously proposed oil-impregnated bearings described above have problems such as poor lubrication and complicated shapes that increase costs.

Therefore, as bearings for small motors for automobiles, oil-impregnated bearings having a shape as shown in FIG. 7, that is, inner diameter-aligned metal l (so-called claw-type metal) are usually used. However, the inner diameter alignment type metal also has a problem in that the bearing efficiency is lower than that of a ball bearing.

With the inner diameter alignment type metal 1 mentioned above, when used for a long time,
It has been found that when the rotary shaft 2 comes into contact with the porous bearing surface 1a due to uneven contact due to a load or the like, the sliding portion (the uneven contact portion) is crushed and becomes non-porous, resulting in better lubrication.

The present invention focuses on the above points and attempts to solve the problems with conventional oil-impregnated bearings, and provides an oil-impregnated bearing that provides good lubrication from the beginning of use, has high efficiency, and has a long life. The purpose is to

A bearing is composed of a porous part that penetrates and retains lubricating oil, and a non-porous part placed on a part of the bearing surface, and the rotating shaft supported by the bearing is pressed into contact with the part of the bearing surface that is pressed by the load. The present invention provides an oil-impregnated bearing characterized by comprising a positioning portion for arranging the non-porous portion.

As the above-mentioned oil-impregnated bearing, it is preferable to use an inner-diameter alignment type in which the inner peripheral surface is tapered from both ends and has a protrusion in the center, and the above-mentioned porous part is made of a sintered material such as Cu-based or Cu-Fe-based. The non-porous portion is made of a soft pure metal such as white metal or an alloy, and is disposed on a part of the inner circumferential surface of the porous part and constitutes a part of the bearing surface.

Furthermore, the above-mentioned positioning part specifically includes a positioning protrusion that is one end of the non-porous part that protrudes from the porous part in the axial direction, a protrusion provided in the porous part, and one end of the non-porous part. This is a recess provided in the

Function The oil-impregnated bearing according to the present invention comprises a porous portion that penetrates and retains lubricating oil and a non-porous portion disposed on a part of the bearing surface, and the rotating shaft supported by the bearing is pressed by a load. Since the positioning part for arranging the non-porous part is provided in the part of the bearing surface that is pressed against the bearing surface, the structure is similar to that of a bearing in which the porous part is collapsed due to one-sided contact.
Provides good lubrication. That is, when the rotating shaft contacts the non-porous part, the temperature of the non-porous part rises, and the oil seeps into the porous part and reaches the contact part,
The pumping action provides good lubrication.

Retsuji Ooni Next, the present invention will be explained in detail based on embodiments shown in the drawings.

The oil-impregnated bearing 10 of the present invention shown in FIGS. 1 and 2 is an inner-diameter centering type metal, and consists of a porous portion 20 and a non-porous portion 30 disposed in a part of the porous portion 20.

The porous portion 20 is made of Cu-based sintered material and has a substantially cylindrical shape. The inner circumferential surface 20a of the porous portion 20, together with a non-porous surface 30a to be described later, constitutes a bearing surface 50 on which the rotating shaft 40 is disposed. The inner circumferential surface 20a is tapered by approximately α=1° in the axial direction from both ends 20b and 20c.
The protrusion 2 extends over the entire circumferential direction of the axial center of 0a.
It is set as I. The material of the porous portion 20 is not limited to the Cu-based sintered material, but any sintered material that is normally used in oil-impregnated bearings may be used, such as Fe-Cu-based sintered material. Alternatively, a trace amount of another substance may be added to these sintered materials.

The non-porous portion 30 is made of white metal and has a shape that is disposed on the inner peripheral surface 2Oa side of the porous portion 20 and forms a part of the bearing surface 50 as described above. That is, as shown in FIG. 3, the non-porous material 30 has one surface 30a having a curved surface shape having the same curvature as the inner peripheral surface 20a of the porous portion 20,
Further, the surface 30a is tapered by approximately α-V from the ends 30b and 30c, and a protrusion 31 is provided at the center in the length direction. Further, the length of the non-porous part 30 is the same as that of the porous part 2.
0, and one end of the non-porous portion 20 that projects when placed in the porous portion 20 is used as a positioning protrusion 32. The positioning protrusion 32 is provided to position the oil-impregnated bearing IO so that the rotating shaft 40 makes partial contact with the non-porous portion 30 when the oil-impregnated bearing 10 is fixed. Note that the positioning portion of the oil-impregnated bearing 1O is the positioning protrusion 32.
For example, protrusions may be provided on the end surface of the porous portion 30 as in a modified example described later, or,
Recesses may be provided in the non-porous portion 30 and positioning may be performed using these. Further, the material of the non-porous portion 30 is not limited to the above-mentioned white metal, and soft pure metals or alloys may be used.

In the manufacturing process of the oil-impregnated bearing 10 described above, first, a molding die (
A non-porous portion 30 is disposed within the non-porous portion (not shown).

Next, the blended, weighed and mixed sintered material powder (Cu-based sintered material in this example) for the porous portion is poured into this molding die and molded. After that, the porous part 2 is sintered in a predetermined atmosphere and conditions, and then recompressed and sized.
The above-mentioned taper is attached to the inner circumferential surface 20a of 0. Finally, impregnation is carried out as usual to allow the porous portion 20 to penetrate and retain the lubricating oil.

Note that cutting may be performed together with or in place of the sizing described above. Further, the material of the non-porous portion 30 is desirably one having a similar melting point for sintering with the powder of the sintering material. Furthermore, a non-porous portion may be formed by plating or the like.

Next, the operational characteristics of the oil-impregnated bearing IO of the above embodiment will be explained.

As shown in FIG. 2, when the rotating shaft 40 receives a force in the direction indicated by the arrow F1 due to a load and slides while being pressed against the protrusion 31 of the non-porous portion 30, the non-porous portion 30
The temperature of the porous portion 20 surrounding the non-porous portion 30 increases. Then, the lubricating oil that has permeated inside the porous portion 20 oozes out onto the surface 30a of the non-porous portion 30, and good lubrication is achieved by the pump action.

Further, even when F1 becomes large, that is, when a high load is applied, the oil film strength in the non-porous portion 30 is high, so that the oil film does not run out and provides good lubrication.

Furthermore, even under low temperature conditions, the oil film in the non-porous portion 30 is retained without being absorbed by the porous F420.
Even if the outflow of lubricating oil from the porous portion 20 declines, good lubrication can be maintained.

45th! J and FIG. 5 show a state in which the oil-impregnated bearing 10 of the above embodiment is applied to a worm shaft 61 of a fiber motor 60 of an automobile.

In this case, the worm shaft 61 formed integrally with the motor output shaft is pressed in the direction indicated by arrow F by the load from the worm wheel 62, and the worm shaft 61 is pressed against the bearing surface 50 of the oil-impregnated bearing IO. The oil-impregnated bearing 10 is positioned by the positioning protrusion 32 and attached to the housing 63 so that the non-porous portion 30 is located.

As described above, the oil-impregnated bearing according to the present invention is applied to the wiper motor 60.
When applied to the worm shaft 61, when the worm shaft 61 is pressed against the non-porous portion 30 of the bearing surface 50 by the load shown by the arrow F from the earth wheel 62, the pumping action described above will improve the performance. This provides good lubrication, improves bearing efficiency, and reduces wear, extending life.

FIG. 6 shows a modification of the oil-impregnated bearing according to the present invention. The oil-impregnated bearing of this modification is of the inner diameter alignment type similar to the above-mentioned embodiment, but has a non-porous portion 35 provided with a protrusion 36. Porous 1S
It is arranged only in a part of the inner circumferential surface 20a of 20 in the axial direction. Furthermore, a positioning protrusion 23 is provided on the end face of the porous portion 20 as a positioning portion. The other configurations and operational features of the modified example are the same as those of the above-described embodiment, so the same reference numerals are given and the description thereof will be omitted.

In the above-described embodiments and modifications, the oil-impregnated bearing was of the inner-diameter alignment type, but the present invention is not limited to this. There may be some ordinary plain bearings.

Effect As is clear from the above explanation, in the oil-impregnated bearing according to the present invention, the portion of the bearing surface where the rotating shaft is pressed and pressed is formed of non-porous material, and the other portion is formed of porous material. Therefore, a strong oil film is formed on the pressed portion, providing good lubrication. Therefore, the oil-impregnated bearing of the present invention has various advantages, such as a reduced coefficient of friction and improved efficiency, as well as reduced wear and extended life.

[Brief explanation of drawings]

FIG. 1 is a plan view showing an embodiment of the present invention, FIG. 2 is a cross-sectional view taken along the line ■-■ in FIG. 1, FIG. 3 is a perspective view showing the non-porous part in FIG. 1, and FIG. The figure is a schematic plan view showing the wiper motor equipped with the oil-impregnated bearing shown in Fig. 1, Fig. 5 is a partially enlarged view of section A in Fig. 4, Fig. 6 is a sectional view showing a modification of the present invention, and Fig. is a sectional view showing a conventional inner diameter centering type metal. 20... Porous part, 30.35... Non-porous part, 40... Rotating shaft.

Claims (2)

[Claims] 1. A bearing is composed of a porous part that penetrates and retains lubricating oil, and a non-porous part placed on a part of the bearing surface, and the rotating shaft supported by the bearing is pressed into contact with the part of the bearing surface that is pressed by the load. An oil-impregnated bearing comprising a positioning part for arranging the non-porous part. 2. The oil-impregnated bearing according to claim 1, wherein the bearing is of an inner diameter alignment type.