JP2514379Y2 - Oil-impregnated bearing with non-porous part - Google Patents

Description

[Detailed description of the device]

[0001]

BACKGROUND OF THE INVENTION The present invention relates to an oil-impregnated bearing (OILES metal) having a non-porous portion, especially in a small motor vehicle for automobiles where it is difficult to lubricate the bearing. It is preferably used for a motor used in a state in which the position is biased in a specific direction, and is intended to improve the lubricating oil retaining performance in the non-porous portion arranged at the specific contact position.

[0002]

2. Description of the Related Art Conventionally, small motors for automobiles such as wiper motors, for example, have a worm gear mechanism in which a worm gear is integrally formed with or connected to a motor output shaft and which meshes with a worm wheel to transmit a rotational force. When used, the contact position between the motor output shaft and its bearing is used in a state of being biased in a specific direction. In such a motor, when a high output is required, the bearing load becomes high, and therefore a ball bearing having a high bearing load is generally used.

However, since ball bearings have problems in terms of cost, noise, etc., it is unavoidable that a sliding bearing G consisting of oil-containing bearings is often used as shown in FIG. The contact surface F was markedly worn, the life was short, and there was a problem in terms of durability.

As a countermeasure against the above wear, a structure in which a bearing member having a small porosity is arranged so as to wrap a segment-shaped bearing member having a large porosity to reduce the amount of wear and prolong the life (see Japanese Patent Publication No. 35-13253). ) Has been done. However, the proposed bearing has a complicated shape, has a problem in terms of cost, and has a drawback that it is not practical.

In order to solve the above-mentioned conventional drawbacks, the applicant of the present invention has previously disclosed, in Japanese Patent Application No. 2-173816, an oil-impregnated bearing in which a non-porous member is arranged on a specific sliding contact surface where the contact with the shaft is biased. Is proposed. In the oil-impregnated bearing provided with this non-porous portion, when the shaft is rotating, the lubricating oil is hermetically held between the shaft and the bearing in the disposition region of the non-porous portion, resulting in high pressure and high bearing load. Therefore, there is an advantage that the amount of wear can be reduced and good lubrication can be maintained.

[0006]

In the oil-impregnated bearing in which the non-porous portion is arranged in the region of the sliding contact surface which is pressed by the load of the rotating shaft and brought into pressure contact, the lubricating oil is mixed with the shaft and the non-porous portion. In order for the bearings to be hermetically held to achieve ideal lubrication, severe conditions are required. That is, it is necessary that the porosity of the non-porous portion is completely zero, and that the surface of the rotating shaft is completely free of fine scratches in the rotating direction. If there is a flaw in the direction of rotation of the rotary shaft during machining of the rotary shaft, this flaw will act as an outflow groove for the lubricating oil, increasing the pressure of the lubricating oil between the shaft and the non-porous bearing. Disappear. As a result, the ideal lubrication state of the above bearing collapses,
The sliding contact surface of the non-porous portion may momentarily contact the shaft, and this contact causes wear and noise.

The present invention is an improvement of the oil-impregnated bearing proposed by the applicant of the present invention, and does not meet the above-mentioned severe conditions, that is, even if the rotating shaft has fine scratches (grooves), Even if the porosity of the porous part is not completely zero, lubricating oil can be retained in the bearing area where the rotating shaft and the non-porous part are installed, and an oil-impregnated bearing that can achieve good lubricating performance is provided. It is a thing.

[0008]

That is, according to the present invention, a porous portion for permeating and holding lubricating oil and a non-porous portion provided at a portion of a bearing surface where a rotating shaft supported by the bearing is pressed against by an eccentric load are provided. A plurality of bearings each having a structure in which a peripheral edge of the non-porous portion forms a closed curve on the sliding contact surface and is sealed in the sliding contact surface. It is intended to provide an oil-impregnated bearing having a non-porous portion, which is provided with fine oil sump grooves.

The oil sump groove is formed in a strip shape extending in a direction orthogonal to the rotating direction of the rotating shaft. When it is formed in the direction orthogonal to the rotation direction of the rotating shaft in this way, it can be used both when the rotating shaft rotates in one direction and when it rotates forward and backward.

When the rotary shaft is rotatable in one direction, the oil sump grooves may be arranged in a mountain shape inclined in the rotational direction from both sides in the axial direction toward the center.

In the present invention, the sliding contact surface of the non-porous portion is
Since the peripheral edge forms a closed curve on the sliding contact surface and multiple fine oil sump grooves are provided in the sliding contact surface as a sealed structure, the lubrication brought into this sliding contact surface Oil is stored in these fine oil sump grooves. Therefore, even if there are fine scratches in the direction of rotation of the rotating shaft and the lubricating oil flows out from these scratches, and even if the porosity of the non-porous material is not completely zero, the sliding contact surface Since the lubricating oil is retained between the rotating shafts, the hydraulic pressure between the shaft and the bearing of the non-porous portion is maintained with almost no decrease. Therefore, it is possible to reliably obtain a hydraulic pressure that can repel the axial load, prevent momentary metal contact between the shaft and the bearing, and always maintain an ideal lubrication state.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described in detail with reference to the embodiments shown in the drawings. 1 to 5 show a first embodiment according to the present invention, in which an oil-impregnated bearing 1 is an inner diameter aligned type, and except for a part of a sliding contact surface described later, a porous material made of a sintered material such as Cu-based material. The porous portion 2 is formed by the porous portion 2, and lubricating oil is permeated and held in the holes of the porous portion 2 to form an oil-impregnated bearing. The inner peripheral surface of the bearing 1 is tapered from both axial ends 1a and 1b at an angle α (α = 1 ° in the present embodiment) so as to project over the entire circumferential direction at the central portion in the axial direction. The inner peripheral surface of the portion 3 is a bearing surface 4.

A sliding contact surface of a bearing surface 4, which receives an axial load unevenly by a rotating shaft 5 supported by the bearing 1, that is,
A non-porous portion 6 is provided in a partial area in the circumferential direction of the bearing surface 4 shown in FIG. The non-porous portion 6 is formed of a normal porous material with a required thickness from the surface of the porous material by crushing using a pressing tool at the time of sizing in one of the bearing processing steps.

The non-porous portion 6 is formed of white metal or the like as disclosed in the above-mentioned prior application of the present applicant, and after the non-porous portion is placed in the molding die at the time of manufacturing the bearing. Alternatively, the powder of the sintered material for the porous portion may be poured and molded.

As shown in FIGS. 3 to 5, on the substantially entire sliding contact surface of the non-porous portion 6, a direction orthogonal to the rotating direction of the rotating shaft 5 shown by the arrow X in FIG. 3, that is, the bearing. 1
A large number of fine strip-shaped oil sump grooves 7 extending in the axial direction are engraved. These oil sump grooves 7 are discontinuous as shown in FIG. 4, and discontinuous portions 8 are provided alternately in the substantially circumferential direction.

The depth of the oil reservoir groove 7 is preferably about several μm or less, and the pitch P between the grooves arranged in parallel in the circumferential direction is preferably twice or more the groove width W.

Next, the operational characteristics of the above bearing will be described.
When the rotating shaft 5 receives a pressing force in a direction indicated by an arrow F in FIG. 1 due to a load and presses against the non-porous portion 6 and slides, the temperature of the non-porous portion 6 rises, and then the non-porous portion 6 The temperature of the porous portion 2 around 6 rises. By this heating, the porous portion 2
The lubricating oil that has permeated into the inside of the material leaks out and flows into the sliding contact surface of the non-porous portion 6 by the pumping action.

The lubricating oil brought into the sliding contact surface of the non-porous portion 6 is stored in a large number of fine oil reservoir grooves 7 engraved on the contact surface, and the non-porous portion 6 is slid. The amount of lubricating oil retained on the dynamic contact surface increases.

Therefore, the sliding contact surface spreads, and the surface of the rotating shaft 5 has minute scratches in the rotating direction, and a small amount of lubricating oil flows out to the bearing surface of the porous portion 2 in the rotating direction from these scratches. However, since the amount of lubricating oil accumulated on the sliding contact surface of the non-porous portion 6 is large, the hydraulic pressure between the sliding contact surface of the non-porous portion 6 and the rotary shaft 5 is hardly reduced. Maintained.

Therefore, for example, even when the load F on the rotating shaft 5 becomes large, the oil film strength on the surface of the non-porous portion 6 is high, so that the oil film is not broken and the rotating shaft 5 and the non-porous member 6 are not porous. It is possible to prevent the moment when the sliding contact surface of the portion 6 makes metal contact, and it is possible to always maintain the fluid lubrication state. Even under low temperature conditions, the oil film in the non-porous portion 6 is not porous.
Since the oil is retained without being absorbed by, the good lubrication can be retained even if the outflow of the lubricating oil from the porous portion 2 is weakened.

FIG. 6 shows a second embodiment of the present invention in which the direction of the oil sump groove 7'which is formed on the sliding contact surface of the non-porous portion 6 is changed. The oil-impregnated bearing 1'of the second embodiment is a bearing of a rotating shaft which rotates in one direction indicated by an arrow X'in the figure,
The oil sump groove 7'is inclined in the direction of rotation X'toward the center from both ends in the axial direction. That is, the oil sump groove 7'has a shape that is folded in a mountain shape in the rotational direction. The oil sump grooves 7'are arranged continuously or discontinuously from one end in the axial direction toward the central portion, are discontinuous at the apex of the mountain, and are arranged continuously or discontinuously toward the other end.

In the oil-impregnated bearing 1 ', the lubricating oil caught in the sliding contact surface of the non-porous portion 6 provided with the oil sump groove 7'is positively moved to the axial center portion of the sliding contact surface. The oil pressure of the central portion is raised by being scraped up, and a so-called dynamic pressure bearing state can be realized. Therefore, it is possible to further improve the lubrication performance and reduce the bearing wear.

[0023]

As is apparent from the above description, in the oil-impregnated bearing according to the present invention, the bearing surface with which the rotating shafts are unevenly contacted is a non-porous portion, and the sliding contact surface of this non-porous portion is , Its peripheral edge forms a closed curve on the sliding contact surface, and a plurality of fine oil sump grooves having a closed structure are provided in the sliding contact surface, and lubricating oil is stored in the oil sump grooves. Since the decrease in oil pressure can be prevented, even if there are fine scratches in the rotating direction of the rotating shaft, and even if the porosity of the non-porous part is not completely zero, the rotating shaft is pressed and slid. An oil film with high strength can be retained on the contact surface. Therefore, good lubrication can be obtained, the coefficient of friction can be reduced, the amount of wear can be reduced, and the life can be extended.

[Brief description of drawings]

FIG. 1 is an axial sectional view of an oil-impregnated bearing in which a rotary shaft according to a first embodiment of the present invention is supported.

FIG. 2 is a side view of FIG.

FIG. 3 is a cross-sectional view of a state in which the rotary shaft of FIG. 1 is removed.

FIG. 4 is an enlarged view of a main part of FIG. 3;

FIG. 5 is a sectional view of FIG.

FIG. 6 is a sectional view similar to FIG. 3, showing a second embodiment of the present invention.

FIG. 7 is a side view of a conventional bearing.

[Explanation of symbols]

 1 Oil-impregnated bearing 2 Porous part 4 Bearing surface 5 Rotating shaft 6 Non-porous part 7 Oil sump groove

Claims (3)

(57) [Scope of utility model registration request] 1. A bearing comprising a porous portion for permeating and retaining lubricating oil, and a non-porous portion provided at a portion of a bearing surface where a rotating shaft supported by the bearing is pressed against by an eccentric load. On the sliding contact surface of the quality portion, a plurality of fine oil sump grooves having a closed edge are formed on the sliding contact surface and a closed structure is provided in the sliding contact surface. An oil-impregnated bearing having a non-porous portion. 2. The oil-impregnated bearing according to claim 1, wherein the oil sump groove has a strip shape extending in a direction orthogonal to the rotation direction of the rotating shaft. 3. The supported rotating shaft rotates in one direction, and the oil sump groove has a strip shape, and the rotating shaft is rotated from both axial sides of the sliding contact surface toward a central portion. The oil-impregnated bearing according to claim 1, wherein the oil-impregnated bearing is arranged in a mountain shape that is inclined in the rotation direction of the shaft.