JP6624559B2 - Plain bearing - Google Patents

Description

  The present invention relates to a technology of a sliding bearing, and more particularly, to a technology of a sliding bearing in which a half member obtained by dividing a cylinder into two in parallel with an axial direction is arranged vertically.

  2. Description of the Related Art Conventionally, a plain bearing having a half-split structure in which two members obtained by dividing a cylindrical shape into two parts, which is a bearing for supporting a crankshaft of an engine, is known. Further, there is a structure in which the width of the bearing is reduced in order to reduce the sliding area of the bearing and obtain an effect of reducing friction. However, when the width of the bearing was reduced, the amount of spilled oil increased. Therefore, a bearing is known in which a relief portion (narrow groove) is formed on both ends in the axial direction of the bearing on the entire circumference (for example, see Patent Document 1).

JP-T-2003-532036

  However, in the conventional bearing having a narrow groove formed on the entire circumference, the load capacity is reduced due to the reduced sliding area, the oil film thickness required for good lubrication cannot be secured, and the total oil spilled out. The amount was large.

  In view of the above, the present invention provides a sliding bearing capable of obtaining a friction reducing effect and suppressing a total oil spill amount.

  The problem to be solved by the present invention is as described above. Next, means for solving the problem will be described.

That is, according to claim 1, a plain bearing in which a half member obtained by dividing a cylinder into two parts in parallel with the axial direction is disposed vertically, and an axial end of the lower half member is provided on the upstream side in the rotational direction. A narrow groove is provided in the circumferential direction up to a predetermined bearing angle which is a position on the upstream side in the rotational direction from a position where the oil film pressure gradient is maximum from the mating surface.

According to a second aspect of the present invention, there is provided a plain bearing in which a half-split member obtained by dividing a cylinder into two parallel to the axial direction is vertically arranged, and an axial end of the lower half-split member is provided with a rotational upstream side. A narrow groove is provided in the circumferential direction from the mating surface to a predetermined bearing angle, and the length of the narrow groove is set to a length at which the reduction rate of the minimum oil film thickness by the narrow groove is 20% or less. .

  Further, in claim 3, a peripheral portion is formed outside the narrow groove in the axial direction, a height of the peripheral portion from the bottom of the narrow groove is higher than 0 mm, and a contact surface with the shaft of the slide bearing. It is formed so as to be lower.

  The present invention has the following effects.

  That is, by providing such a narrow groove that does not hinder the generation of the oil film pressure, the sliding area can be reduced, the friction reducing effect can be obtained, and the total oil spill amount can be suppressed.

FIG. 1 is a front view showing a plain bearing according to an embodiment of the present invention. (A) A plan view showing a half member constituting a sliding bearing according to a first embodiment of the present invention. FIG. 2B is a sectional view taken along line II of FIG. FIG. 2C is a sectional view taken along line II-II of FIG.

  Next, an embodiment of the invention will be described. FIG. 1 is a front view of the sliding bearing 1, in which the vertical direction of the screen is the vertical direction, and the front and rear directions of the screen are the axial directions (front and rear directions).

First, a half member 2 that constitutes the sliding bearing 1 according to the first embodiment will be described with reference to FIGS. 1 and 2.
The sliding bearing 1 is a cylindrical member, and is applied to a sliding bearing structure of a crankshaft 11 of an engine as shown in FIG. The sliding bearing 1 is composed of two half members 2. The two half members 2 have a shape obtained by dividing a cylinder into two parallel to the axial direction, and are formed so that the cross section becomes a semicircular shape. In the present embodiment, the half members 2 are arranged vertically and the mating surfaces are arranged left and right. When the crankshaft 11 is supported by the slide bearing 1, a predetermined gap is formed, and lubricating oil is supplied to the gap from an oil passage (not shown).

  FIG. 2A shows the upper and lower half members 2. In the present embodiment, the rotation direction of the crankshaft 11 is a clockwise direction as viewed from the front as shown by an arrow in FIG. The bearing angle ω is 0 degrees at the right end position in FIG. 2B and positive in the counterclockwise direction in FIG. 2B. That is, in FIG. 2B, the bearing angle ω at the left end position is defined as 180 degrees, and the bearing angle ω at the lower end position is defined as 270 degrees.

A groove is provided in the inner circumference of the upper half member 2 in the circumferential direction, and a circular hole is provided at the center. In addition, mating surfaces are arranged on the left and right of the upper half member 2.
A narrow groove 3 is formed at an axial end of a contact surface on the inner periphery of the lower half member 2.
The narrow groove 3 is provided on the lower half member 2. In the present embodiment, two narrow grooves 3 are provided in parallel in the axial direction.

  Specifically, the narrow groove 3 is provided in the circumferential direction from the mating surface on the upstream side in the rotation direction of the crankshaft 11 (the bearing angle ω is 0 degree) toward the direction in which the bearing angle ω is negative (clockwise). . That is, in the lower half member 2, the mating surface on the right side in FIG. 2B is the mating surface on the upstream side in the rotational direction, and the mating surface on the left side in FIG.

The downstream end of the narrow groove 3 in the rotation direction is disposed at a position where the bearing angle ω is ω1.
Here, the position where the bearing angle ω is ω1 is a position on the upstream side in the rotation direction from the position P1 of the minimum oil film thickness. The minimum oil film thickness is the minimum thickness of the oil film formed on the inner peripheral surface of the bearing, and indicates the relationship between engine speed, bearing radius, bearing width, oil viscosity, and crank angle and bearing load. It is calculated based on The position P1 of the minimum oil film thickness exists where ω is 270 ° or more and 315 ° or less.

  The narrow groove 3 is provided at an upstream end of the lower half member 2. With this configuration, foreign matter and the like generated on the upstream side in the rotation direction can be easily taken into the narrow groove 3, so that damage to the crankshaft 11 can be prevented.

  The position where the bearing angle ω is ω1 is a position on the upstream side in the rotation direction from the position P2 where the oil film pressure gradient is maximum. The oil film pressure gradient is the rate of change (slope) of the oil film pressure, and the position P2 where the oil film pressure gradient is maximum exists at ω of 270 ° or more and 315 ° or less, It exists upstream from the position P1.

  The length 1 of the narrow groove 3 is set so that the reduction rate of the minimum oil film thickness by the narrow groove 3 becomes 20% or less. The reduction rate of the minimum oil film thickness is a value obtained by subtracting the ratio (%) of the minimum oil film thickness of the slide bearing 1 provided with the narrow groove 3 to the minimum oil film thickness of the slide bearing not provided with the narrow groove from 100%. It is. The length at which the reduction rate of the minimum oil film thickness is 20% or less is the minimum oil film thickness necessary for the sliding bearing 1 to perform safe lubrication. The absolute value of the difference between the bearing angle ω1 at the upstream end in the rotation direction and the bearing angle (ω = 0 °) at the downstream end in the rotation direction is the length at which the minimum oil film thickness reduction rate is 20% or less. The length is 90 ° or less.

The width of the narrow groove 3 is formed to be w, as shown in FIG.
In addition, the height d from the bottom surface of the narrow groove 3 to the contact surface is formed to be shorter than the height D from the outer peripheral surface of the half member 2 to the contact surface.
Further, the peripheral edge portion 2a forming the axially outer surface of the narrow groove 3 has a height h from the bottom surface of the narrow groove 3 smaller than a height d from the bottom surface of the narrow groove 3 to the contact surface. Is formed. That is, the outer peripheral edge portion 2 a is formed so as to be one step lower than the contact surface with the surrounding crankshaft 11.

  Since the peripheral portion 2a is formed so as to be one step lower than the contact surface with the surrounding crankshaft 11, the crankshaft 11 is inclined and comes into contact with only one end in the axial direction (a state in which the crankshaft 11 hits one side). In this case, the chance of contact between the peripheral portion 2a and the crankshaft 11 can be reduced, so that the peripheral portion 2a can be prevented from being damaged.

  Further, since the peripheral portion 2a is formed so as to be one step lower than the surrounding abutting surface, the gap at the axial end of the slide bearing 1 is widened, the amount of sucked-back oil is increased, and the total amount of spilled oil is increased. Is reduced.

As described above, the sliding bearing 1 in which the cylinder half is divided into two parts in parallel with the axial direction is a sliding bearing 1 in which the lower half member 2 has an axially upstream end in the axial direction. A narrow groove 3 is provided in a circumferential direction from a side mating surface to a predetermined bearing angle.
With such a configuration, by providing the narrow groove 3 which does not hinder the generation of the oil film pressure, it is possible to obtain a friction reduction effect while reducing the sliding area, and to suppress the total oil spill amount. be able to.

In addition, the narrow groove 3 is provided from the rotation direction upstream side mating surface to a position on the rotation direction upstream side from the position P1 of the minimum oil film thickness.
With this configuration, the narrow groove 3 can be provided avoiding the position where the bearing load is most applied, so that a reduction in load capacity can be suppressed, a friction reducing effect can be obtained, and the total oil spillage can be achieved. The amount can be reduced.

Further, the narrow groove 3 is provided from the rotationally upstream mating surface to a position on the rotationally upstream side from the position P2 where the oil film pressure gradient is maximum.
With this configuration, it is possible to obtain a friction reducing effect while suppressing a decrease in load capacity, and to suppress the total amount of spilled oil.

The length 1 of the narrow groove 3 is set so that the reduction rate of the minimum oil film thickness by the narrow groove 3 becomes 20% or less.
With this configuration, it is possible to obtain a friction reducing effect while suppressing a decrease in load capacity, and to suppress the total amount of spilled oil.

Further, a peripheral edge 2a is formed on the outer side in the axial direction of the narrow groove 3, and the height h of the peripheral edge 2a from the bottom surface of the narrow groove 3 is higher than 0 mm, and is higher than the contact surface of the slide bearing 1 with the crankshaft 11. It is formed to be lower.
With this configuration, when the crankshaft 11 is inclined and comes into contact with only one end in the axial direction (a state in which the crankshaft 11 contacts one side), the chance of contact between the peripheral edge portion 2a and the crankshaft 11 is reduced. Therefore, it is possible to prevent the peripheral portion 2a from being damaged.

DESCRIPTION OF SYMBOLS 1 Slide bearing 2 Half member 2a Peripheral edge 3 Narrow groove 11 Crankshaft

Claims (3)

A sliding bearing in which a half member obtained by dividing a cylinder into two parts in parallel with an axial direction is arranged vertically,
At the axial end portion of the lower half member, a narrow groove is formed in the circumferential direction up to a predetermined bearing angle that is a position on the upstream side in the rotation direction from a position where the oil film pressure gradient is maximum from the rotation side upstream mating surface. ,
A sliding bearing characterized by the following. A sliding bearing in which a half member obtained by dividing a cylinder into two parts in parallel with an axial direction is arranged vertically,
At the axial end portion of the lower half member, a narrow groove is provided in the circumferential direction from the rotation direction upstream mating surface to a predetermined bearing angle,
The length of the narrow groove was set to a length at which the reduction rate of the minimum oil film thickness by the narrow groove was 20% or less,
A sliding bearing characterized by the following. A peripheral edge was formed on the outer side in the axial direction of the narrow groove, and the height of the peripheral edge from the bottom of the narrow groove was higher than 0 mm and lower than the contact surface of the slide bearing with the shaft. ,
The sliding bearing according to claim 1 or 2 , wherein:

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