JP2002227822A - Sliding bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sliding bearing with an excellent productivity capable of avoiding a local strong contact of a bearing metal with a bearing pin. SOLUTION: The end edge of the inner peripheral surface 2a of the bearing metal 2 in slidable contact with the outer peripheral surface of the bearing pin 3 is chamfered 2b, and a cut-in 3a gradually decreasing the outside diameter of the bearing pin 3 toward a shaft end is provided in the bearing shaft 3 at an area opposed to the bearing metal 2 to gradually increase a clearance between the inner peripheral surface 2a of the bearing metal 2 and the outer peripheral surface of the bearing pin 3 non-linearly in the end edge portion of the bearing metal 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a plain bearing,
In particular, the present invention relates to a sliding bearing used around a crankshaft of an engine or a compressor.

[0002]

2. Description of the Related Art For example, a reciprocating engine employs a slide bearing in which a bearing metal 2 attached to a large end of a connecting rod 1 is brought into sliding contact with an outer peripheral surface of a crank pin 3 as shown in FIG. In such a sliding bearing, when a large pressure due to combustion is applied to the connecting rod 1, an oil film interposed between the bearing metal 2 and the crankpin 3 is compressed. 4 is a crank arm.

[0003] Since the bearing metal 2 is deformed by the reaction force of the oil film as shown in FIG. 3 and the oil film thickness at the metal end is reduced, the vicinity of the edge of the bearing metal 2 is applied to the crank pin 3. Strong wear may cause local wear, and in extreme cases, seizure may be caused. Also, it is well known that the oil film thickness as described above decreases toward the end of the bearing metal as shown in FIG. 4, and the degree of the decrease increases as the Pmax of the engine increases. Have been.

Accordingly, conventionally, for example, Japanese Patent No. 30450
As disclosed in Japanese Patent Publication No. 00-00, etc., the inner peripheral surface of the bearing metal is formed into a so-called crowning shape, and the gap between the inner peripheral surface of the bearing metal and the outer peripheral surface of the crankpin in the no-load state is set near the edge of the bearing metal. , The oil film thickness in the vicinity of the end of the bearing metal is ensured even in a load state, thereby avoiding an obstacle due to a strong hit.

However, it is extremely difficult to machine the inner peripheral surface of the bearing metal with high accuracy or to chamfer the edge of the inner peripheral surface with a nonlinear curve (for example, a quadratic curve) for crowning. Therefore, there is a problem that the production cost is increased.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and provides a sliding bearing excellent in productivity which can avoid a local strong contact between a bearing metal and a bearing pin. The challenge is to do.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention chamfers an edge of an inner peripheral surface of a bearing metal which is in sliding contact with an outer peripheral surface of a bearing pin, while reducing the outer diameter of the bearing pin. It is characterized in that it gradually decreases toward the shaft end in a region facing the bearing metal. The invention according to claim 2 is characterized in that multi-stage chamfering is performed on the edge of the inner peripheral surface of the bearing metal that slides on the outer peripheral surface of the bearing pin.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings. Parts having the same functions as those of the conventional example shown in FIG. 3 are denoted by the same reference numerals, and detailed description thereof will be omitted. FIG. 1 is a cross-sectional view showing an embodiment of a slide bearing according to the present invention, in which an edge of an inner peripheral surface 2a of a bearing metal 2 attached to a large end of a connecting rod (not shown) is chamfered 2b by a flat surface. It has a pseudo crowning shape.

On the other hand, a cut 3a is provided near the end of the crank pin 3 functioning as a bearing pin, so that the crank pin 3
Is gradually reduced from an intermediate portion of the position facing the chamfer 2b to the outside, so that the crank pin 3 also has a crowning shape. Therefore, the gap between the bearing metal 2 and the crank pin 3 is chamfered 2a and cut 3a.
And gradually increases toward the edge of the bearing metal 2. Note that the outside diameter of the crank pin 3 is gradually increased outside the cutout 3 a outside the area facing the bearing metal 2, thereby preventing concentration of stress at the joint with the crank arm 4.

In the sliding bearing having such a configuration, when the bearing metal 2 is assembled to the crank pin 3 functioning as a bearing pin, the chamfer 2b of the bearing metal 2 is formed.
And the cut 3a of the crank pin 3 are combined to form a gap between the two. Therefore, the gap between the bearing metal 2 and the crank pin 3 increases nonlinearly toward the end of the bearing metal 2, so that the inner peripheral surface edge of the bearing metal functions in the same manner as crowning in which the edge of the inner peripheral surface is chamfered with a nonlinear curve. To avoid local hits.

For this reason, there is no need to perform complicated machining with poor workability as in the prior art, and the chamfering 2b of the inner peripheral surface 2a of the bearing metal 2 and the shaving 3a near the end of the crankpin 3 are eliminated. As a result, the productivity of the plain bearing is increased.

In the above embodiment, the oil film thickness is obtained by combining the pseudo crowning shape in which the edge of the inner peripheral surface 2a of the bearing metal 2 is chamfered 2b with a plane and the crowning by cutting 3a near the end of the crank pin 3. Although a gap corresponding to this is ensured, the starting position of the cut 3a is not limited to that of the embodiment, and the cut 3a may be provided from the inside of the chamfer 2b.

In the above embodiment, the bearing metal 2 and the crank pin 3
Is gradually increased in accordance with the oil film thickness, but the same function can be achieved by other configurations.

FIG. 2 is a sectional view of a bearing metal according to another embodiment of the present invention. In the present embodiment, by providing two chamfers 2b and 2c by planes at the edge of the inner peripheral surface 2a of the bearing metal 2, the chamfer 2b,
The crowning shape according to 2c is made to approach the minimum oil film thickness curve shown by the two-dot chain line in FIG.

Therefore, as in the present embodiment, the bearing metal 2
When a multi-stage chamfer 2b, 2c is provided at the edge of the inner peripheral surface 2a to form a crowning shape, there is an advantage that the workability is greatly improved as compared with the crowning by chamfering a nonlinear curve. The crowning shape can be approximated by the minimum oil film thickness curve by providing a chamfer of more than one step, or by providing a not-shown cut in the crank pin 3 in addition to the two-step chamfers 2b and 2c.

[0016]

As is apparent from the above description, the present invention combines pseudo crowning by chamfering the inner peripheral edge of the bearing metal and crowning by shaving the bearing pin to combine the inner peripheral surface of the bearing metal with the bearing pin. The gap between the outer peripheral surfaces of the bearing metal is gradually increased non-linearly at the edge of the bearing metal, so as compared to the conventional crowning in which the inner edge of the bearing metal is chamfered with a nonlinear curve. Workability is greatly improved.

According to the second aspect of the present invention, the intended purpose can be achieved only by performing multi-stage chamfering on the inner peripheral surface edge of the bearing metal. Can be easily obtained.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of a plain bearing according to the present invention.

FIG. 2 is a cross-sectional view showing another embodiment of the plain bearing according to the present invention.

FIG. 3 is a cross-sectional view showing a specific example of a sliding bearing.

4 is a characteristic diagram showing a distribution of a minimum oil film thickness in the slide bearing shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Connecting rod 2 Bearing metal 2a Inner peripheral surface 2b, 2c Chamfering 3 Crank pin (bearing pin) 3a Cutting 4 Crank arm

Claims (2)

[Claims] 1. The method according to claim 1, wherein an outer peripheral surface of the bearing pin is chamfered at an inner peripheral surface of the bearing metal, and an outer diameter of the bearing pin is gradually reduced toward a shaft end in a region facing the bearing metal. Characterized by a plain bearing. 2. A sliding bearing wherein an inner peripheral surface of a bearing metal slidingly contacting an outer peripheral surface of a bearing pin is subjected to multi-stage chamfering.