JPH0429128Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a thrust plain bearing that is improved to receive thrust loads evenly.

(Prior Art) A thrust plain bearing is used, for example, in the crankshaft of an engine as shown in FIG. 21
is the crankshaft, 22 is the main bearing housing, 23
is a half-split flat bearing, and 10 is a thrust flat bearing.

The thrust plain bearing 10 has a semi-annular shape, and an oil clearance δ of 50 to 100 μm is provided between the housing 22 and the annular side surface of the crank arm 21a.
It is accepted in the annular recess of the cylinder, and thrust load resistance and sliding properties are required. Conventionally, thrust plain bearings as shown in FIGS. 8A and 8B have been used.

11 is a semi-annular back metal, 12 is a bearing alloy fixed to the annular surface of the back metal 11, and 13 is a bearing alloy 12.
A pair of oil grooves 14 formed in the middle part of the bearing alloy 12 are relief parts obtained by obliquely cutting both ends of the bearing alloy 12.
The bearing alloy 12 is formed to have a uniform thickness except for the relief portion 14 and the oil groove 13.

(Problem to be Solved by the Invention) During engine operation, the annular side surface of the crank arm 21a fills the gap between the oil clearance δ and the bearing alloy 12 due to the rotation of the crankshaft and the engagement and disengagement of the clutch. Slides into contact with the surface.

In that case, due to the machining and finishing condition of the crankshaft, especially the connection part between the crank arm 21a and the crank journal 21b, and the torque applied to the crank pin at the tip of the crank arm 21a, etc.
The base of the crank arm 21a comes into contact with the surface of the bearing alloy 12 of the thrust bearing, and as shown by the plurality of vertical lines in FIG. producing part A;
This may cause the bearing alloy 12 to peel off from the back metal 11 or cause seizure.

(Means for Solving the Problems) The present invention aims to provide a thrust plain bearing that receives thrust loads evenly, and its configuration is as follows.

A bearing alloy is fixed to a semi-annular back metal, a pair of oil grooves are formed in the middle part, and relief parts are formed at both ends. In the cross section perpendicular to the chord connecting the end surfaces of This is a plain thrust bearing.

Therefore, in conventional thrust plain bearings, the thickness of the bearing is thinner on the inner circumferential edge side and the relief part side where strong contact occurs, so when the engine is running,
Strong contact of the annular side surface of the crank arm with the above portion is avoided.

(Example) Examples of the thrust plain bearing according to the present invention are shown in the first to
This will be explained based on FIG.

FIGS. 1A, 1B, and 1C show a first embodiment, in which a thrust flat bearing 1 has a bearing alloy 3 fixed to the side surface of a back metal 2 having a semi-annular shape. Both 3a are a pair of oil grooves provided at intervals in the middle part of the bearing alloy 3 in the circumferential direction, and both 3b are relief parts formed by obliquely cutting the bearing alloy 3 at both ends. It is. A plurality of vertical lines indicate tapered portions 4, and on the relief portion 3b side of each oil groove 3a, the thickness of the bearing alloy 3 is gradually reduced from the outer edge of the oil groove 3a toward the relief portion 3b. . Therefore, as shown in FIG. The tapered portion 4 gradually becomes thinner.

The thickness of the inner peripheral edge of the bearing alloy 3 or the minimum wall thickness that is the boundary thickness with the relief part 3b is 20 to 60 μm from the original thickness, that is, the thickness between both oil grooves 3a.
It is preferably thin and 0.1 mm or more.

Therefore, the thickness of the bearing alloy 3 can be set thinner on the inner circumferential edge side and closer to both relief portions 3b, and the thrust force that the bearing alloy 3 receives from the annular side surface of the crank arm 21a can be approximately equalized.

FIG. 2 shows a second embodiment, in which the same reference numerals as in the first embodiment indicate the same parts, and the explanation thereof will be omitted.

In this case, the tapered portion 5 indicated by the plurality of vertical lines is
On the relief part 3b side of each oil groove 3a, the oil groove 3a
The thickness of the bearing alloy 3 is gradually reduced from the outer inner edge in the circumferential direction toward the relief portion 3b, and is provided under the same thickness conditions as in the first embodiment.

FIG. 3 shows a third embodiment, in which the same reference numerals as in the first embodiment indicate the same parts. In this case, the tapered portion 6 shown by the plurality of vertical lines is in contact with the inner peripheral edge of the bearing alloy 3,
The thickness of the bearing alloy 3 is gradually reduced from the part parallel to the chord connecting both relief parts 3b toward both relief parts 3b, and is provided under the same thickness conditions as in the first embodiment. .

FIG. 4 shows a fourth embodiment, in which the same reference numerals as in the first embodiment indicate the same parts. In this case, the tapered portion 7 shown by the plurality of vertical lines is formed by gradually decreasing the thickness from the apex of the outer peripheral edge of the bearing alloy 3 toward both relief portions 3b, and has the same thickness as in the first embodiment. It is set as a condition.

FIG. 5 shows a fifth embodiment, in which the same reference numerals as in the first embodiment indicate the same parts. In this case, the tapered portion 8 indicated by the plurality of vertical lines is formed by gradually decreasing the thickness in the radial direction from the outer circumferential edge to the inner circumferential edge of the bearing alloy 3, and as shown in FIG. In a cross section perpendicular to the chord connecting the end surfaces of the bearing alloy 3b, that is, a cross section taken along the line bb, the bearing alloy 3 forms a tapered portion 8 that gradually becomes thinner toward the inner peripheral edge side and the relief portion 3b side.

FIG. 6 shows a sixth embodiment, in which the same reference numerals as in the first embodiment indicate the same parts. In this case, the tapered portion 9 shown by the plurality of vertical lines is formed so that the thickness thereof gradually decreases from the apex of the outer peripheral edge of the back metal 2 toward the back surface of both relief portions 3b. The minimum wall thickness, which is the boundary thickness with the relief portion 3b, is preferably 20 to 60 μm thinner than the original thickness, that is, the thickness at the apex of the outer peripheral edge.

In the above-described second to sixth embodiments, the portions that are likely to be hit strongly are made thinner, so that they have substantially the same effect as the first embodiment.

Of course, the first to sixth embodiments are also applicable to the flange of a flanged plain bearing.

(Effect of the invention) As can be understood from the above explanation, the flat thrust bearing of the invention is thinner toward the inner peripheral edge and relief portion of the bearing alloy, where the side surface of the crank arm tends to contact strongly. Because of this, the thrust force from the crank arm can be balanced and received, eliminating the risk of the bearing alloy peeling off from the backing metal or seizing.

[Brief explanation of the drawing]

FIG. 1A is a front view of the first embodiment of the thrust plain bearing according to the present invention, FIG. 1B is a side view of the same, and FIG.
Figure C is a sectional view taken along the line a-a of Figure 1A, Figure 2A is a front view of the second embodiment, Figure 2B is a side view of the same, and Figure 3A is a cross-sectional view of the third embodiment. 3B is a side view of the embodiment, FIG. 4A is a front view of the fourth embodiment, FIG. 4B is a side view of the fourth embodiment, and FIG. 5B is a side view of the embodiment, FIG. 5C is a cross-sectional view taken along the line b-b of FIG. 5A, and FIG.
Fig. 6B is a side view of the same side, Fig. 7 is a sectional view of main parts showing the relationship between a conventional thrust plain bearing and a crankshaft, and Fig. 8A is a front view of a conventional thrust plain bearing. Figure 8B is the same side view. 1... Thrust flat bearing, 2... Back metal, 3... Bearing alloy, 3a... Oil groove, 3b... Relief part,
4, 5, 6, 7, 8, 9... Taper part, 21...
...Crankshaft, 21a...Crank arm, δ...
...Oil clearance, A...Strong contact area of conventional thrust plain bearings.

Claims (1)

[Scope of utility model registration request] A bearing alloy is fixed to a semi-annular back metal, a pair of oil grooves are formed in the middle part, and relief parts are formed at both ends. In the cross section perpendicular to the chord connecting the end faces of the bearing, at least the thickness of the bearing on the side of the relief part from the oil groove is gradually thinned toward the inner peripheral edge and the relief part side to form a tapered part to equalize surface pressure. A thrust plain bearing characterized by the following features: