JP2014047841A - Bearing for crank shaft of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bearing for a crank shaft of an internal combustion engine for effectively preventing deformation, breakage of an engagement part of a semicircular thrust bearing and a semi-cylindrical slide bearing integrally combined with each other by engagement relation between pawls and notches.SOLUTION: Two pawls 34 extending inward in a radial direction are projected by being separated from each other in the circumferential direction at an inner peripheral side of a semicircular thrust bearing 30. The pawls have: first sides 34b on the farther side and second circular-arc-shaped sides 34c on the nearer side from both ends in the circumferential direction of the semicircular thrust bearing 30. Circular-arc-shaped cutout parts 32b are formed at an inner peripheral side on both ends in the circumferential direction of the semicircular thrust bearing 30, and circular arcs of the circular-arc-shaped cutout parts also form the second circular-arc-shaped sides of the pawls. When the inner diameter center of the semi-cylindrical slide bearing 20 and the inner diameter center of the semicircular thrust bearing 30 are at the same position, the second circular-arc-shaped sides 34c of the pawls 34 become dimensions so as not to contact the outer peripheral surface of the semi-cylindrical slide bearing 20.

Description

  The present invention relates to a crankshaft bearing for an internal combustion engine, and more specifically to a crankshaft bearing in which a semicircular thrust bearing is assembled to each of a pair of semicylindrical slide bearings to be combined in a cylindrical shape. It is.

  The crankshaft of the internal combustion engine is supported at the lower part of the cylinder block of the internal combustion engine via a main bearing comprising a pair of semi-cylindrical slide bearings at its journal portion. Of the pair of semi-cylindrical slide bearings, one or both of the semi-cylindrical slide bearings are used in combination with a semi-circular thrust bearing. The semicircular thrust bearing is assembled and attached in a hook shape along one or both of two axial end face side edges (that is, width direction side edges) of at least one semicylindrical slide bearing. The assembling is performed in a plurality of corresponding notches (that is, recesses) formed in the axial side of the semi-cylindrical slide bearing with at least two claws spaced apart from each other on the inner periphery of the semi-circular thrust bearing. This is done by fitting and engaging.

  A pair of semi-cylindrical plain bearings are cylindrically held in a split bearing housing, but the semi-cylindrical plain bearing in the free state before being assembled into the split bearing housing is centered in the circumferential direction. The curvature radius is gradually increased from the region toward both ends in the circumferential direction. Then, in a state where the pair of semi-cylindrical slide bearings are incorporated in the bearing holding holes of the split type bearing housing (restraint state), each butt end region of the pair of semi-cylindrical slide bearings has the shape of the bearing holding hole. Thus, the shape is a shape deformed by pressing toward the center of the circle rather than the initial semicircular shape (the shape in a free state before being incorporated into the bearing housing). In other words, each semi-cylindrical plain bearing attached to each half of the split bearing housing before assembly is held in close contact with the bearing housing half by its own elastic restoring force generated by the deformation.

That is, the semi-cylindrical plain bearing in the free state has different radii of curvature in the circumferential central region and the circumferential end regions, and the latter is larger than the former. When the semicircular thrust bearing is assembled to the semi-cylindrical slide bearing using the engagement relationship between the claw and the notch (recess), the claw is placed against one side of the notch of the semi-cylindrical slide bearing in the free state. As a result, the semicircular thrust bearing and the semicylindrical slide bearing are mechanically coupled to each other. Therefore, it can be assembled to the split bearing housing as a single assembly in which the semicircular thrust bearing and the semicylindrical slide bearing are integrally combined. In this assembled state, each butted end region of the pair of semi-cylindrical slide bearings is deviated toward the center of curvature, and the pair of semi-cylindrical slide bearings are deformed following the shape of the bearing holding hole, The semicircular thrust bearing is outside the split bearing housing and does not deform at all. Also, the deformation of the semi-cylindrical slide bearing eliminates the interference / coupling relationship between the notch and the pawl, and the semi-circular thrust bearing becomes slightly movable in the axial direction of the crankshaft with respect to the semi-cylindrical slide bearing. . As a result, during operation of the internal combustion engine, automatic positioning is performed in which the thrust load receiving surface of the semicircular thrust bearing is parallel to the side surface of the crank web that applies the axial load of the crankshaft.
Patent documents showing the combination of a semi-cylindrical slide bearing and a semi-circular thrust bearing are listed below.

JP 47-7011 A JP 59-147115 A Japanese National Patent Publication No. 7-504017 WO 2009/062904 A1

  As a recent trend, the output of an internal combustion engine has been increased, and in order to reduce the weight of the internal combustion engine, the bearing housing of the crankshaft tends to be reduced in rigidity. In this connection, the bearing housing is easily elastically deformed, and during operation of the internal combustion engine, the claws of the semicircular thrust bearing and the notches of the semi-cylindrical slide bearing repeatedly interfere with each other and the claws and the notches are deformed. Or the problem of breaking.

Here, the damage problem of the nail and the notch will be described.
When the crankshaft rotates at high speed during operation of the internal combustion engine, a large variable load is repeatedly applied to the bearing housing, the low rigidity rigid bearing housing is repeatedly elastically deformed, and the bearing holding hole shape of the bearing housing is also repeatedly changed. Thus, the bearing holding hole diameter in the direction along the combination surface of the split bearing housing (hereinafter referred to as the horizontal direction. Similarly, in the combination of a pair of semi-cylindrical slide bearings, the direction along the combination surface is also referred to as the horizontal direction). Repeat increasing and decreasing. Accordingly, the shape of the pair of semi-cylindrical plain bearings held in the bearing holding hole of the bearing housing is repeatedly changed. That is, when the horizontal inner diameter of the bearing holding hole is increased, the horizontal outer diameter of the pair of semi-cylindrical slide bearings is increased. As a result, the claws of the semicircular thrust bearing and the sides of the cutout of the semicylindrical slide bearing collide with each other and interfere strongly. Due to the repeated collision and interference, the claw and the notch are deformed and broken.

  Thus, it is an object of the present invention to cause repeated elastic deformation of a pair of semi-cylindrical slide bearings held by a bearing housing, in which a bearing housing holding a crankshaft bearing is repeatedly elastically deformed during operation of the internal combustion engine. The crankshaft of an internal combustion engine that can effectively prevent deformation and breakage of the claw and the notch of the semicircular thrust bearing and the semi-cylindrical slide bearing that are integrally combined by the engagement relationship between the claw and the notch against the phenomenon that occurs. It is to provide a bearing for an automobile.

In light of this object, according to the present invention, the following crankshaft bearing for an internal combustion engine is provided.
A crankshaft bearing for an internal combustion engine used as a cylindrical body by combining a pair of semi-cylindrical plain bearings,
A semicircular thrust bearing is assembled to at least one of the pair of semicylindrical slide bearings, and the semicircular thrust bearing is attached along one or both of the two axial sides of the semicylindrical slide bearing. Has been established,
The semicircular thrust bearing has an outer periphery and an inner periphery, both of which are arc-shaped, and two claws extending radially inward are provided in the circumferential direction on the inner periphery of the semicircular thrust bearing. The claw has a first side that is far from the circumferential ends of the semicircular thrust bearing and a second arc-shaped side that is close to the semicircular thrust bearing. At both ends in the circumferential direction of the circular thrust bearing, arc-shaped notches are formed on the inner periphery, and the arc of the arc-shaped notch also forms the arc-shaped second side of the claw. And
In the semi-cylindrical slide bearing, two notches are formed on the side in the axial direction to which the semi-circular thrust bearing is attached, spaced apart from each other in the circumferential direction. The two claws of the semicircular thrust bearing are in engagement with each other,
The circumferential length of the claw is larger than the circumferential length of the notch, and when the inner diameter center of the semi-cylindrical slide bearing and the inner diameter center of the semicircular thrust bearing are at the same position, The arc-shaped second side of the claw is not in contact with the outer peripheral surface of the semi-cylindrical plain bearing,
When the semi-cylindrical slide bearing is deformed in a direction in which both ends of the circumferential direction of the semi-cylindrical slide bearing are separated, the first side of the claw interferes with one side of the notch, and A crankshaft of an internal combustion engine configured to suppress the deformation of the semi-cylindrical slide bearing by causing the arc-shaped second side of the claw to interfere with the outer peripheral surface of the semi-cylindrical slide bearing. Bearings.
One of the pair of semi-cylindrical slide bearings may be a semi-cylindrical slide bearing according to the present invention, and the other may be a semi-cylindrical slide bearing not provided with a thrust bearing. .

  In the crankshaft bearing according to the first embodiment of the present invention, the circumferential length of the claw is 0.5 mm or more larger than the circumferential length of the notch.

  In the crankshaft bearing according to the second embodiment of the present invention, the arc of the arcuate notch has the same curvature as the arc of the outer periphery of the semicircular thrust bearing.

  In the crankshaft bearing according to the third embodiment of the present invention, the two claws are in line-symmetrical positions with respect to a straight line in the radial direction that bisects the length of the inner periphery.

  In the crankshaft bearing according to the fourth embodiment of the present invention, each of the claws has a corner portion located on a side farther from the circumferential end surface of the claw base portion connected to the body of the semicircular thrust bearing. It protrudes from the inner periphery so as to exist in the range of a central angle of 15 ° to 45 ° measured from the circumferential end face.

  In the crankshaft bearing according to the fifth embodiment of the present invention, the claw is displaced in the back direction of the semicircular thrust bearing that is opposite to the thrust load receiving surface, and at least a part of the claw is It protrudes beyond the back surface.

In the crankshaft bearing according to the sixth embodiment of the present invention, in addition to the two claws, a third claw protrudes from the inner periphery of the semicircular thrust bearing, and the third claw is Between the two nails, located in the central region of the inner peripheral length,
The semi-cylindrical plain bearing is formed with a third notch positioned between the two notches, and the third notch is engaged with the third pawl, Due to the joint relationship, relative rotation in the circumferential direction of the semicircular thrust bearing with respect to the semicylindrical slide bearing is prevented.

In the crankshaft bearing according to the seventh embodiment of the present invention, the first and second gap support protrusions protrude from the inner periphery of the semicircular thrust bearing, and the first and second gap support protrusions Each of the semicircular thrust bearings is located between the claw and a central position that bisects the length of the inner periphery of the semicircular thrust bearing, and the height of the gap support protrusion is set to the pair of semicylindrical slides. In a static state in which the bearing is assembled and restrained in the bearing housing of the crankshaft, the top of the gap support projection is dimensioned to contact the outer peripheral surface of the semi-cylindrical slide bearing.
It should be avoided that the first and second gap support protrusions and the third claw are made continuous. During engine operation, due to the elastic deformation of the semi-cylindrical slide bearing due to the dynamic load of the crankshaft, the outer peripheral surface of the semi-cylindrical slide bearing abuts against the clearance support protrusion of the semicircular thrust bearing, and the clearance support protrusion is elastically deformed. To do. Therefore, when the gap support protrusion and the claw are connected to each other, the gap support protrusion is deformed to the claw, the claw is elastically deformed, and is detached from the notch of the semi-cylindrical slide bearing, or the claw side edge and This is because there is a risk that the side of the notch will interfere strongly, causing deformation and damage to the nail and the notch.

  According to a second aspect of the present invention, there is provided an internal combustion engine including the aforementioned crankshaft bearing.

(1) In the crankshaft bearing of the present invention, two claws extending radially inwardly project from the inner periphery of the semicircular thrust bearing so as to be spaced apart from each other in the circumferential direction. The claw has a first side far from the circumferential ends of the semicircular thrust bearing and an arcuate second side near the circumferential ends of the semicircular thrust bearing. An arc-shaped notched portion is formed on the inner periphery, and the arc of the arc-shaped notched portion also forms the arc-shaped second side of the claw, and the semi-cylindrical plain bearing has Two notches are formed on the side in the axial direction to which the semicircular thrust bearing is attached, spaced apart from each other in the circumferential direction, and the two notches are formed on the second side of the semicircular thrust bearing. The claw is engaged with each other, and the circumferential length of the claw is determined by the notch. When the inner diameter center of the semi-cylindrical slide bearing and the inner diameter center of the semi-circular thrust bearing are at the same position, the arcuate second side of the claw is the semi-cylindrical side. The dimension is such that it does not contact the outer peripheral surface of the plain bearing. Therefore, the crankshaft bearing of the present invention is incorporated in the bearing holding hole of the bearing housing that holds the crankshaft bearing, and during the operation of the internal combustion engine, a pair of the bearing housing is subjected to repeated elastic deformation due to the action of dynamic load. When the semi-cylindrical slide bearing is repeatedly elastically deformed in the horizontal direction, the outer peripheral surface of the semi-cylindrical slide bearing comes into contact with the arc-shaped second side of the claw protruding from the inner periphery of the semi-circular thrust bearing. The elastic deformation of the semi-cylindrical plain bearing is prevented. As a result, the movement of the claw of the semicircular thrust bearing in the notch of the semi-cylindrical slide bearing is suppressed, the repeated collision between the first side of the claw and the side of the notch is also suppressed, and the claw and the notch are deformed. Damage can be effectively prevented.
In addition, by adopting a configuration in which an arc-shaped notch portion is formed on the inner periphery, when a semicircular thrust bearing is punched from a material plate with a press, each semicircular thrust bearing can be punched adjacently. Loss can be reduced and manufacturing costs can be reduced.

(2) In the crankshaft bearing according to the first embodiment of the present invention, the circumferential length of the claw is 0.5 mm or more larger than the circumferential length of the notch. With this configuration, when the pair of semi-cylindrical slide bearings are repeatedly elastically deformed in the horizontal direction, the outer peripheral surface of the semi-cylindrical slide bearing is a circular arc of a claw projecting from the inner periphery of the semi-circular thrust bearing. The second side can be reliably contacted.

(3) In the crankshaft bearing according to the second embodiment of the present invention, the arc of the arc-shaped notched portion has the same curvature as the arc of the outer periphery of the semicircular thrust bearing. With this configuration, when the semicircular thrust bearing is punched out of the material plate with a press, the material loss can be further reduced, and the manufacturing cost can be reduced.

(4) In the crankshaft bearing according to the third embodiment of the present invention, the two claws are located symmetrically with respect to a straight line in the radial direction that bisects the length of the inner periphery. With this configuration, it is possible to evenly reduce the load applied to the two claws, and it is easy to manufacture.

(5) In the crankshaft bearing according to the fourth embodiment of the present invention, each of the claws has a corner portion located on the far side from the circumferential end surface of the claw base portion connected to the body of the semicircular thrust bearing. And projecting from the inner periphery so as to exist in a range of a central angle of 15 ° to 45 ° measured from the end surface in the circumferential direction. This projecting position is limited when the corner of the corner exceeds the position of the circumferential angle of 45 °, the crankshaft bearing of the present invention is in a semi-cylindrical plain bearing in a free state before being incorporated in the bearing housing. A semi-cylindrical plain bearing with insufficient engagement and interference relationship between the two claws and the two notches due to the shape with a radius of curvature that gradually increases from the circumferential central region toward both circumferential end surfaces. And the semicircular thrust bearing cannot be integrally connected, and if the corner is located at a circumferential angle of less than 15 °, both ends of the semicylindrical plain bearing are arranged in the circumferential direction. This is because a not-not-formed part cannot be secured, so that it becomes difficult to provide a notch, and the range in which the arc-shaped notch part can be installed is reduced.

(6) In the crankshaft bearing according to the fifth embodiment of the present invention, the claw is deviated in the back direction of the semicircular thrust bearing that is opposite to the thrust load receiving surface, and at least the claw A part protrudes beyond the back surface.

(7) In the crankshaft bearing according to the sixth embodiment of the present invention, in addition to the two claws, a third claw projects from the inner periphery of the semicircular thrust bearing. A nail is located between the two nails in a central region of the inner peripheral length,
The semi-cylindrical plain bearing is formed with a third notch positioned between the two notches, and the third notch is engaged with the third pawl, Due to the joint relationship, relative rotation in the circumferential direction of the semicircular thrust bearing with respect to the semicylindrical slide bearing is prevented. By adopting such a configuration, it is possible to eliminate the possibility that the semicircular thrust bearing is brought into contact with the sliding surface due to the contact relationship with the sliding surface of the crankshaft.

(8) In the crankshaft bearing according to the seventh embodiment of the present invention, the first and second gap support protrusions protrude from the inner periphery of the semicircular thrust bearing, and the first and second gaps Each of the support protrusions is located between a central position that bisects the length of the inner periphery of the semicircular thrust bearing and the claw, and the height of the gap support protrusion is set to the pair of semi-circular thrust bearings. In a static state in which the cylindrical slide bearing is assembled and restrained in the bearing housing of the crankshaft, the top of the gap support protrusion is dimensioned to contact the outer peripheral surface of the semicylindrical slide bearing, and the semicylindrical slide It is provided in order to maintain a gap (gap perpendicular to the bearing center line) between the outer peripheral surface of the bearing and the inner periphery of the semicircular thrust bearing. If the outer peripheral surface of the semi-cylindrical plain bearing and the inner periphery of the semi-circular thrust bearing come into contact with each other, the semi-circular thrust bearing is restrained in the axial direction due to the interference relationship between the two, and the crank shaft applies an axial load. -Automatic positioning (alignment) is not performed in which the thrust load receiving surface of the semicircular thrust bearing is parallel to the side surface of the web.

FIG. 3 is a side view of a semicircular thrust bearing and a semicylindrical plain bearing according to the first embodiment of the present invention that are in a combination relationship with each other. The side view of the semicircle thrust bearing shown in FIG. The side view of the semi-cylindrical plain bearing shown in FIG. The A direction arrow directional view of the semi-cylindrical slide bearing shown to FIG. 1 and FIG. The figure which shows the bearing principal part in the state in which this invention bearing was integrated in the bearing housing and the semi-cylindrical slide bearing was restrained. FIG. 6 is a view corresponding to FIG. 5, showing a state in which the semi-cylindrical slide bearing is elastically deformed and the outer peripheral surface of the semi-cylindrical slide bearing is in contact with the arcuate second side of the semi-circular thrust claw during engine operation. FIG. 6 is a sectional view taken along line VII-VII in FIG. 5. FIG. 7 is a sectional view taken along line VIII-VIII in FIG. 6. 8 is a modification of the semicircular thrust bearing shown in FIG. The figure which shows a part of semicircular thrust bearing as a modification of the semicircular thrust bearing shown in FIG. 1, FIG. The B direction arrow directional view in FIG. The figure which shows a part of semicircular thrust bearing as a modification of the semicircular thrust bearing shown in FIG. 1, FIG.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
FIG. 1 shows a half body 10 of a bearing for a crankshaft of an internal combustion engine according to a first embodiment of the present invention. The half body 10 is a semicylindrical slide bearing 20 and a semicircular thrust bearing 30 which are in combination with each other. It consists of. The semicircular thrust bearing 30 is attached in the form of a pair of hooks along both axial end faces 22 of the semicylindrical slide bearing 20 (that is, both ends in the axial direction or the width direction) (however, in the drawings) Only one semicircular thrust bearing 30 is visible). In the present embodiment, a configuration in which a pair of semicircular thrust bearings 30 is attached to the semicylindrical slide bearing 20, but a single semicircular thrust bearing is attached to the semicylindrical slide bearing. In some cases.
The semicircular thrust bearing 30 includes a thrust bearing main body 32 and two claws 34 protruding from the inner periphery of the thrust bearing main body 32. Each of the two claws 34 has a corner portion 34a of a claw base connected to the semicircular thrust bearing main body 32 on the side far from each of the circumferential end faces of the semicircular thrust bearing, and the circumferential end face 32a. The circumferential angle θ1 measured from each is projected from the inner periphery of the thrust bearing body 32 so as to be in the range of 15 ° to 45 ° (FIG. 2).
The claw 34 has a first side 34b far from both circumferential ends of the semicircular thrust bearing and an arc-shaped second side 34c on the near side. At both ends in the circumferential direction of the semicircular thrust bearing, arc-shaped notches 32b are formed on the inner periphery. The arc of the arc-shaped notched portion 32 b also forms the arc-shaped second side 34 c of the claw 34. The curvature of the arcuate notched portion 32 b is the same as the curvature of the outer diameter of the thrust bearing body 32.
The semi-cylindrical plain bearing 20 is formed with two notches 24 on each of the axial end faces 22 (FIGS. 3 and 4). The two notches 24 and the two claws 34 are engaged with each other. The semi-cylindrical plain bearing 20 is partially thinned on the bearing inner peripheral surface side over the entire circumferential length along the axial end surface 22 to which the semicircular thrust bearing 30 is attached. The thickness reduction region 20a is formed, and two notches 24 are formed in the thickness reduction region 20a so as to be separated from each other in the circumferential direction (FIGS. 7 and 8).
The circumferential length of the claw 34 in the inner periphery of the thrust bearing body 32 is larger than the circumferential length of the outer peripheral surface of the semicylindrical slide bearing 20 of the notch 24, and the inner diameter center of the semicylindrical slide bearing. When the center of the inner diameter of the semicircular thrust bearing and the center of the inner diameter of the semicircular thrust bearing are at the same position, the second arcuate side 34c of the claw 34 is not in contact with the outer peripheral surface of the semicylindrical slide bearing 20 (FIG. 5).

  FIG. 1 shows a free state before the bearing half 10 is assembled to the bearing housing H, and the first side 34 b of the claw 34 interferes with and contacts the side 24 a of the notch 24. This interference and contact relationship is obtained by the non-circular shape of the semicylindrical plain bearing 20 in the free state. FIG. 5 shows a restrained state in which the bearing half 10 is assembled to the bearing housing H, and the first side 34 b of the claw 34 is separated from the side 24 a of the notch 24.

Operation of the Bearing Half 10 The bearing half 10 shown in FIG. 1 has a semicylindrical plain bearing 20 and a semicircular thrust in which the first side 34b of the claw 34 interferes with and contacts the side 24a of the notch 24. As a single assembly in which the bearing 30 is integrally combined, the split bearing housing H can be assembled. When a pair of semi-cylindrical slide bearings 20 combined in a generally elliptical shape are incorporated in the split bearing housing H, the pair of semi-cylindrical slide bearings 20 are restrained by the circular bearing holding holes of the split bearing housing H. Thus, the pair of semi-cylindrical plain bearings 20 is forcibly deformed from an initial shape (generally elliptical) to a circular shape, and as a result, the interference and contact relationship between the claw 34 and the notch 24 is eliminated, and the claw 34 The one side 34b is separated from the side 24a of the notch 24 (FIG. 5). In addition, when the bearing half body 10 is incorporated in the split bearing housing H, the semicircular thrust bearing 30 is not restrained by the split bearing housing H. As can be seen from FIG. 7, the semicircular thrust bearing 30 is along the side surface of the split bearing housing H, and the reduced thickness region 20 a of the semicylindrical slide bearing 20 protrudes outside the split bearing housing H. This is because the claw 34 of the semicircular thrust bearing 30 engages with the notch 24 formed in the thickness reduction region 20a.
In the state where the bearing half 10 is incorporated in the split bearing housing H, the semicircular thrust bearing 30 is slightly movable in the axial direction of the crankshaft with respect to the semicylindrical slide bearing 20. As a result, when the internal combustion engine is operated, the thrust load receiving surface (surface having the lubricating oil groove 38) of the semicircular thrust bearing 30 is automatically parallel to the side surface of the crank web that applies the axial load of the crankshaft. Positioning (alignment) is performed. Further, the arc-shaped second side 34c of the claw 34 of the semicircular thrust bearing 30 is spaced apart from the outer peripheral surface of the semicylindrical slide bearing 20 (see FIGS. 5 and 7).
When the engine is in operation, the split bearing housing H is elastically deformed repeatedly under the dynamic load of the crankshaft, and the pair of semi-cylindrical plain bearings 20 are also in a direction along their butt end faces 26 (that is, horizontal). Direction), and elastic deformation of diameter expansion and diameter reduction is repeated. When the pair of semi-cylindrical plain bearings 20 expands in the horizontal direction, their outer peripheral surfaces abut against the arcuate second side 34c of the pair of claws 34 of the semicircular thrust bearing 30 (see FIGS. 6 and 8). Excessive diameter expansion of the semi-cylindrical plain bearing 20 is prevented. Therefore, the trouble which the conventional bearing has that the claw 34 of the semicircular thrust bearing 30 abuts the side 24a of the notch 24 at the first side 34b can be successfully suppressed.

  The semicircular thrust bearing 30 includes a thrust bearing body 32, a third claw 35 projecting from the inner periphery of the thrust bearing body 32, and two gap support protrusions 36.

  The semi-cylindrical plain bearing 20 has a third notch 25 formed on each of the axial end faces 22 thereof. The third notch 25 and the third claw 35 are in a relationship of engaging with each other. The notch 25 is configured to prevent relative rotation in the circumferential direction of the semicircular thrust bearing 30 with respect to the semicylindrical slide bearing 20 by engagement with the claw 35. By adopting such a configuration, it is possible to eliminate the possibility that the semicircular thrust bearing 30 rotates with the sliding surface due to the contact relationship with the sliding surface of the crankshaft.

  Further, the claw 35 may be locally welded and joined at the notch 25 of the semi-cylindrical slide bearing 20. This welding connection is such that when the internal combustion engine is operated, when the automatic positioning that is parallel to the side surface of the crank web that applies the axial load of the crankshaft is performed, the welded portion is broken. It is allowed to be welded.

  The two gap support protrusions 36 have a projecting height at which their tips come into contact with the outer peripheral surface of the semi-cylindrical slide bearing when the bearing is incorporated into the bearing holding hole of the bearing housing that holds the crankshaft bearing, Between each claw 34 and the claw 35, it protrudes from the inner periphery of the semicircular thrust bearing body 32. The gap support protrusion 36, the claw 34, and the claw 35 are provided apart from each other. The reason is as described in the paragraph [0016].

About Modifications (1) A semicircular thrust bearing 30A shown in FIG. 9 is a modification of the semicircular thrust bearing 30 shown in FIG. In FIG. 9, a claw 34A projecting from the inner periphery of the thrust bearing body 32A of the semicircular thrust bearing 30A is located inside the semicylindrical slide bearing 20 with respect to the “surface in contact with the bearing housing” of the thrust bearing body 32A. (I.e., in the axial direction of the semi-cylindrical slide bearing 20) and deviated in the direction away from the thrust load receiving surface F of the semi-circular thrust bearing 30 </ b> A.

(2) FIGS. 10 and 11 (viewed in the direction of arrow B in FIG. 10) show a thrust bearing body 32A of a semicircular thrust bearing 30A as a modification of the semicircular thrust bearing 30 shown in FIGS. Only the vicinity of the circumferential end face is shown locally. In a partial region in the vicinity of the circumferential end surface 32a of the thrust bearing body 32A, a taper (T) is applied in such a manner that the thickness of the thrust bearing body 32A gradually decreases from the thrust load receiving surface F toward the circumferential end surface 32a. Has been. The circumferential end surface 32a of the thrust bearing body 32A does not reach the horizontal line HR passing through the butted end surfaces (that is, the circumferential end surfaces) of the pair of semi-cylindrical slide bearings combined in a cylindrical shape. In contrast to the semicircular thrust bearing shown in FIG. 2, the circumferential length of the thrust bearing body 32A is shorter by the length S1 at each circumferential end face 32a. The shape of the tip of the claw 34A where the first side 34b and the arcuate second side 34c of the claw 34A intersect can be a flat surface or an arc surface.

(3) FIG. 12 locally shows a thrust bearing body 32B of a semicircular thrust bearing 30B as a modification of the semicircular thrust bearing 30 shown in FIGS. 1 and 2 only in the vicinity of the circumferential end face thereof. The semicircular thrust bearing 30B is characterized in that an extending portion 32C extending radially outward from the outer periphery of the thrust bearing body 32B is formed in the region near the end face of the thrust bearing body 32B. The extending portion 32C is not limited to the illustrated position, and may be formed at an arbitrary position on the outer periphery of the thrust bearing body 32B. In any case, the role of the extending portion 32C is the positioning of the semicircular thrust bearing 30 and the rotation stopping function.

10: Half body of crankshaft bearing 20: Semi-cylindrical slide bearing 20a: Thickening region 22: Axial end surface 24: Notch 24a: Side 25: Notch 26: Butt end surface 30, 30A, 30B: Semicircular thrust bearing 32, 32A, 32B: Thrust bearing body 32a: Circumferential end face 32b: Arc-shaped notched portion 32C: Extension portions 34, 34A, 34B: Claw 34a: Corner corner portion 34b: First side 34c: Arc-shaped first 2 side 35: claw 36: gap support protrusion 38: lubricating oil groove F: thrust load receiving surface H: bearing housing HR: horizontal line S1: length T: taper portion

Claims (9)

A crankshaft bearing for an internal combustion engine used as a cylindrical body by combining a pair of semi-cylindrical plain bearings,
A semicircular thrust bearing is assembled to at least one of the pair of semicylindrical slide bearings, and the semicircular thrust bearing is attached along one or both of the two axial sides of the semicylindrical slide bearing. Has been established,
The semicircular thrust bearing has an outer periphery and an inner periphery, both of which are arc-shaped, and two claws extending radially inward are provided in the circumferential direction on the inner periphery of the semicircular thrust bearing. The claw has a first side that is far from the circumferential ends of the semicircular thrust bearing and a second arc-shaped side that is close to the semicircular thrust bearing. At both ends in the circumferential direction of the circular thrust bearing, arc-shaped notches are formed on the inner periphery, and the arc of the arc-shaped notch also forms the arc-shaped second side of the claw. And
In the semi-cylindrical slide bearing, two notches are formed on the side in the axial direction to which the semi-circular thrust bearing is attached, spaced apart from each other in the circumferential direction. The two claws of the semicircular thrust bearing are in engagement with each other,
The circumferential length of the claw is larger than the circumferential length of the notch, and when the inner diameter center of the semi-cylindrical slide bearing and the inner diameter center of the semicircular thrust bearing are at the same position, The arc-shaped second side of the claw is not in contact with the outer peripheral surface of the semi-cylindrical plain bearing,
When the semi-cylindrical slide bearing is deformed in a direction in which both ends of the circumferential direction of the semi-cylindrical slide bearing are separated, the first side of the claw interferes with one side of the notch, and A crankshaft of an internal combustion engine configured to suppress the deformation of the semi-cylindrical slide bearing by causing the arc-shaped second side of the claw to interfere with the outer peripheral surface of the semi-cylindrical slide bearing. Bearings.   The crankshaft bearing according to claim 1, wherein a circumferential length of the claw is 0.5 mm or more larger than a circumferential length of the notch.   3. The crankshaft bearing according to claim 1, wherein an arc of the arc-shaped notched portion has the same curvature as an arc of the outer periphery of the semicircular thrust bearing.   The crankshaft according to any one of claims 1 to 3, wherein the two claws are in line symmetry with each other with respect to a straight line in a radial direction that bisects the length of the inner periphery. Bearings.   Each of the claws has a corner portion located on the side far from the circumferential end surface of the claw base portion connected to the body of the semicircular thrust bearing, with a central angle measured from the circumferential end surface of 15 ° to 45 °. The crankshaft bearing according to any one of claims 1 to 4, wherein the crankshaft bearing projects from the inner periphery so as to exist in a range.   The claw is deviated in a back direction of the semicircular thrust bearing that is opposite to a thrust load receiving surface, and at least a part of the claw protrudes beyond the back surface. Item 6. The crankshaft bearing according to any one of Items 1 to 5. In addition to the two claws, a third claw projects from the inner periphery of the semicircular thrust bearing, and the third claw is between the two claws and has a length of the inner periphery. Located in the central area of
The semi-cylindrical plain bearing is formed with a third notch positioned between the two notches, and the third notch is engaged with the third pawl, 7. The relative rotation in the circumferential direction of the semi-circular thrust bearing with respect to the semi-cylindrical slide bearing is prevented by a mating relationship, and is described in any one of claims 1 to 6. Crankshaft bearing.   First and second gap support protrusions project from the inner periphery of the semicircular thrust bearing, and each of the first and second gap support protrusions is a length of the inner periphery of the semicircular thrust bearing. The height of the gap support projection is constrained by the pair of semi-cylindrical slide bearings assembled into the bearing housing of the crankshaft. The crankshaft according to any one of claims 1 to 7, wherein in a static state, the top of the gap support protrusion is dimensioned to contact an outer peripheral surface of the semi-cylindrical slide bearing. Bearings.   An internal combustion engine comprising the crankshaft bearing according to any one of claims 1 to 8.