JP2001032837A - Slide bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the oil film thickness in an axial direction of a bearing surface and to prevent the occurrence of early wear and seizure by a method wherein the end part in an axial direction of a bearing surface is formed in a taper-form state that a diameter is increased toward an end and an oil reservoir part is formed in the taper-form part. SOLUTION: A main bearing serving as a plurality of slide bearings to support the crank shaft of an engine is formed in a cylindrical state by butting upper and lower half-division bearings against each other. The upper and lower half-division bearings are formed such that a bearing alloy 5 is mounted on the inner peripheral surface of a back metal 4 made of copper and an overlay layer 6 is formed on a bearing alloy 5 through plating. In this case, the two end parts in an axial direction of the main bearing are formed in a taper-form state that a diameter is gradually increased toward an end. A plurality of peripherally extending grooves 11 are formed as an oil reservoir part in this taper-form part 10. The groove 11 is formed such that after a groove 12 is formed in the surface of the bearing alloy 5 through a machining work, an overlay layer 6 is formed through plating. This constitution ensures a gap between the bearing surface of a main bearing and the main shaft 13 of a crank shaft and holds lubrication oil in the gap.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a sliding bearing with improved non-seizure properties.

[0002]

The crankshaft of an engine is supported by a plurality of slide bearings called main bearings. There is a crank between the portions (called the main shaft) supported by the main bearing, and the combustion pressure of fuel acts on the crank, so that the main shaft bends and hits one end of the bearing surface of the main bearing.

In the main bearing, the lubricating oil is supplied to the bearing surface through a central oil hole and escapes from both ends, so that the oil film thickness at both ends of the bearing surface is relatively thin. And
When the main shaft hits one end of the bearing surface of the main bearing as described above, the oil film pressure locally increases, and a relatively thin oil film of the portion is broken, and as a result, the main shaft of the crankshaft and the main shaft are separated. Metal contact between the bearing and the bearing surface causes early wear or seizure of the bearing surface.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a sliding bearing which can increase the oil film thickness at an axial end of a bearing surface and can prevent the occurrence of premature wear and seizure. To be.

[0005]

In order to achieve the above object, a plain bearing according to the present invention has a tapered shape in which the axial end of the bearing surface is increased in diameter toward the end. A gap is provided between the end of the surface and the shaft. Since the oil reservoir is provided in the tapered portion, the lubricating oil is stored in the oil reservoir, and the lubricating oil is held in the tapered portion, so that the oil film thickness can be secured. And
Even if the shaft comes into contact with the tapered portion to increase the oil film pressure in the tapered portion, the lubricating oil is held in the tapered portion by the holding action of the oil reservoir, and the oil film thickness is ensured. Therefore, there is no possibility that the oil film is broken and the shaft and the bearing make metal contact.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a main bearing of an engine will be described below with reference to the drawings. 2 and 3 show a main bearing 1 as a plain bearing. As shown in the figure, the main bearing 1 is formed in a cylindrical shape by abutting upper and lower half bearings 2 and 3. The upper and lower half bearings 2 and 3 are formed by mounting a bearing alloy 5 on the inner peripheral surface of a steel back metal 4 and providing an overlay layer 6 on the bearing alloy 5 by plating.

An oil groove 7 extending in the circumferential direction is formed at an axially central portion of an inner peripheral portion of the upper half bearing 2, and the oil groove 7 is formed in an oil hole formed in an upper portion of the upper half bearing 2. 8 open to the outside. Notched grooves 9 are formed at both ends in the circumferential direction of the lower half bearing 3 so as to be continuous with the oil grooves 7 of the upper half bearing 2.

The main bearing 1 composed of the upper and lower half bearings 2 and 3 is attached to a bearing housing (not shown) of an engine block. The lubricating oil discharged from the lubricating oil pump is supplied to the engine block, from the formed oil passage to the oil groove 7 and the notch groove 9 through the oil hole 8, and from the oil groove 7, the notch groove 9 to both upper and lower half bearings. Two, three
And is leaked to the outside from both axial ends.

As shown in FIG. 1, both ends of the main bearing 1 in the axial direction are formed in a tapered shape whose diameter gradually increases toward the end. The tapered portion 10 has a plurality of circumferentially extending grooves 11 as oil reservoirs. Here, the groove 11 is formed in the overlay layer 6 of the upper and lower half bearings 2 and 3. Groove 1 of overlay layer 6
1 is formed by plating the overlay layer 6 after forming the groove 12 on the surface of the bearing alloy 5 by machining.

According to the above construction, the axial end of the main bearing 1 is a tapered portion 10, so that the main bearing 1 is provided between the bearing surface of the main bearing 1 and the main shaft 13 of the crankshaft supported on the bearing surface. A gap is secured. Since the groove 11 is formed in the tapered portion 10, the lubricating oil supplied to the bearing surface from the oil groove 7 or the notch groove 9 and leaking from the end of the main bearing 1 is inserted into the groove 11. As a result, the lubricating oil is held in the gap between the bearing surface of the main bearing 1 and the main shaft 13.

Further, the main shaft 13 of the crankshaft bends as shown by a two-dot chain line in FIG. 1 by receiving the combustion pressure of the fuel acting on the crank. Even when the oil film pressure of the tapered portion 10 is increased and the lubricating oil is pushed out from the end of the main bearing 1, the lubricating oil is held in the tapered portion 10 by the holding action of the groove 11, and the oil film thickness is secured. You. Therefore, there is no possibility that the oil film is broken and the main shaft 13 and the main bearing 1 are brought into metallic contact, and there is no possibility that the main bearing 1 is worn out or seized early.

FIG. 4 shows the result of measuring the oil film thickness from the center to the end of the main bearing 1. The two-dot chain line shows the conventional main bearing without the tapered portion 10, and the solid line shows the main bearing of the present invention. 3 shows a bearing. It is understood from the figure that the present invention has a larger oil film thickness at the end.

The present invention is not limited to the embodiment described above and shown in the drawings, but can be extended or modified as follows. The oil sump may be a small depression. The tapered portion is not limited to a linearly expanding shape as long as the diameter increases toward the end, and is not limited to a linearly expanding shape, such as a combination of a linearly expanding portion and a circularly expanding portion. It may be shaped. Not only the main bearing of the engine,
Widely applicable to plain bearings in general. The sliding bearing may be formed in a cylindrical shape instead of the split shape.

[Brief description of the drawings]

FIG. 1 is a partial sectional view showing one embodiment of the present invention.

FIG. 2 is a sectional view showing the entire main bearing.

FIG. 3 is a perspective view of a main bearing.

FIG. 4 is a diagram showing an oil film thickness.

[Explanation of symbols]

1 is a main bearing, 7 is an oil groove, 9 is a cutout groove, 10 is a tapered portion, 11 is a groove (oil reservoir), and 13 is a main shaft.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor, Sohei Yamada, 2 Sanagecho, Kita-ku, Nagoya City Inside (72) Inventor Atsushi Okado, 2nd Sanagecho, Kita-ku, Nagoya City Daido Metal Industry Co., Ltd. (72) Inventor Kotaro Kashiyama 2 Sanage-cho, Kita-ku, Nagoya F-term (reference) in Daido Metal Industry Co., Ltd. 3J011 AA07 CA04 JA02 KA02 MA03 MA06 MA24 NA01

Claims (2)

[Claims] 1. A sliding bearing wherein an axial end of a bearing surface is formed in a tapered shape whose diameter increases toward the end, and an oil reservoir is formed in the tapered portion. 2. The slide bearing according to claim 1, wherein the oil reservoir is formed of a groove extending in a circumferential direction.