JP4612072B2 - Connecting rod bearing for internal combustion engine - Google Patents

Description

  The present invention provides a connecting rod bearing in which lubricating oil supplied to an inner peripheral surface of a main bearing supporting a crankshaft rotatably supports a crankpin that connects the connecting rod and the crankshaft through an internal lubricating oil passage of the crankshaft. The present invention relates to a connecting rod bearing of an internal combustion engine configured to be supplied to an inner peripheral surface, and the connecting rod bearing includes a pair of semicircular bearings.

  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 composed of a pair of semicircular bearings in its journal portion. For the main bearing, the lubricating oil discharged by the oil pump is formed along the inner peripheral surface of the main bearing from the oil gallery formed in the cylinder block wall through the through-hole formed in the wall of the main bearing. It is fed into the lubricating oil groove. Further, a first lubricating oil passage is formed penetrating in the diameter direction of the journal portion, both end openings of the first lubricating oil passage communicate with the lubricating oil groove, and further from the first lubricating oil passage in the diameter direction of the journal portion. A second lubricating oil passage that branches and passes through the crank arm portion is formed, and this second lubricating oil passage communicates with a third lubricating oil passage that is formed penetrating in the diameter direction of the crank pin. Thus, the lubricating oil sent from the oil gallery in the cylinder block wall into the lubricating oil groove formed in the inner peripheral surface of the main bearing through the through hole formed in the wall of the main bearing is the first lubricating oil passage, The oil is supplied between the sliding surfaces of the crank pin and the connecting rod bearing from the end outlet of the third lubricating oil passage through the second lubricating oil passage and the third lubricating oil passage.

  Lubricating oil sent from the engine cylinder block to the connecting rod bearing portion via the journal portion of the crankshaft may be accompanied by foreign matter present in the lubricating oil passage of each part. If it is sent between the sliding surface of the pin and the connecting rod bearing, the sliding surface of the connecting rod bearing may be damaged. Foreign matter that has entered between the sliding surfaces of the crankpin and the connecting rod bearing needs to be quickly discharged from the sliding surface portion.

Among the main bearings that support the crankshaft journal part that consists of a pair of semicircular bearings as a countermeasure against foreign matter mixed in with the lubricating oil, it has a through-hole that receives supply of lubricating oil directly from the oil gallery in the cylinder block wall There has been a proposal which intends to provide a lubricating oil groove in the circumferential direction over the entire inner circumferential surface of the semicircular bearing to discharge foreign matters accompanying the lubricating oil. If this concept is applied to a connecting rod bearing, the foreign matter discharge effect is not obtained, and not only does the foreign matter stay in the circumferential lubricating oil groove formed over the entire inner peripheral surface of one semicircular bearing of the connecting rod bearing. It has been confirmed by tests that foreign matter is dispersed over the entire sliding surface of the bearing and the bearing is liable to be damaged.
The reason for this is that, generally, the housing that holds the connecting rod bearing is greatly deformed during engine operation, so that the gap between the crank pin and the connecting rod bearing during operation is larger than the gap between the crankshaft journal portion and the main bearing. The foreign matter held in the lubricating oil groove tends to spread over the entire bearing sliding surface, and the foreign matter is distributed also on the sliding surface portion in the “circumferential center portion of the semicircular bearing” that becomes the main load portion, This is because the bearing damage is increased as compared with the case of using a conventional type connecting rod bearing in which the circumferential lubricating oil groove is not provided. This was confirmed by testing.
JP-A-8-277831 JP 2005-69283 A

  An object of the present invention is to provide a connecting rod bearing capable of quickly discharging foreign matter accompanying the lubricating oil sent from the cylinder block of the internal combustion engine through the journal portion of the crankshaft to the connecting rod bearing portion from the connecting rod bearing portion. It is.

In light of the above object, the present invention provides the following connecting rod bearing for an internal combustion engine.
The lubricating oil supplied to the inner peripheral surface of the main bearing that supports the crankshaft passes through the internal lubricating oil passage from the journal portion of the crankshaft to the diametrical through hole of the crankpin, and the crankpin that connects the connecting rod and the crankshaft A connecting rod bearing for an internal combustion engine configured to be supplied to an inner peripheral surface of a connecting rod bearing that is rotatably supported,
The connecting rod bearing comprises a pair of semicircular bearings, one of which is an upper semicircular bearing located on the rod side of the connecting rod large end housing, and the other is a lower semicircular located on the cap side of the connecting rod large end housing. The connecting rod bearing of the type configured as a bearing, wherein the upper semicircular bearing is assembled such that the semicircular circumferential central portion coincides with the central axis of the connecting rod,
Abutting on the front side in the relative rotational direction of the crank pin with respect to the connecting rod bearing, which is at least one of two abutting end surfaces of the paired mating semicircular bearing on the inner peripheral surface of at least one of the semicircular bearings A circumferential groove formed within a range of a maximum circumferential angle of 45 degrees from the end surface toward the circumferential central portion;
In a state where the butted end surfaces of the pair of semicircular bearings are butted against each other, they intersect along the butted end surfaces on the side where the circumferential grooves are formed, and intersect the axis of the connecting rod bearing at a right angle. wherein formed on at least one of the inner peripheral surfaces of the semicircular bearing, possess an axial groove communicating with the circumferential groove as a lubricating oil flow path over the entire length between the plane parallel to both sides,
The circumferential groove cross-sectional area of the groove is, the inner peripheral surface circumferentially central side connecting rod bearing of the internal combustion engine that has been made larger toward the butt end face from.
The preferred size of the circumferential groove is groove width = 1-7 mm and groove depth = 0.1-0.5 mm.
Moreover, the suitable size of the said axial direction groove | channel is groove width = less than 2 mm, and groove depth = 0.1-0.5 mm.

  In one embodiment of the present invention, the circumferential groove is formed at a central position between both sides parallel to a plane perpendicular to the axis of the connecting rod bearing. The outlet of the crankpin diametrical through hole, which is a part of the internal lubricating oil passage of the crankshaft, is usually aligned with the center position between the two sides of the semicircular bearing, and the circumferential groove is connected to the crankpin diameter By aligning with the outlet of the direction through hole, the lubricating oil flows smoothly into the circumferential groove, and the foreign matter accompanying the lubricating oil also flows smoothly in the circumferential groove to the axial groove side. Easy to be guided.

  In another embodiment of the present invention, the groove cross-sectional area of the circumferential groove is increased from the circumferential center side of the inner circumferential surface toward the butt end surface. When this configuration is adopted, the flow velocity of the lubricating oil in the circumferential groove becomes gentle from the circumferential center portion side of the semicircular bearing toward the butt end surface side, and foreign matters accompanying the lubricating oil are circumferentially removed. It flows in the groove without departing from the groove.

  In still another embodiment of the present invention, the groove cross-sectional area of the circumferential groove at the communicating portion with the axial groove is larger than the groove cross-sectional area of the axial groove. With this configuration, the flow velocity of the lubricating oil in the axial groove is larger than that in the circumferential groove, and the foreign matter accompanying the lubricating oil reaching the axial groove is quickly discharged to the outside of the axial groove. Here, the groove cross-sectional area of the axial groove is a state in which the butted end surfaces of a pair of semicircular bearings are butted together and straddles the semicircular bearings on both sides across the butted end surfaces. Groove cross-sectional area defined by the inner wall surface of the groove formed by cutting the part over the entire length between both sides and the virtual inner peripheral surface of both semicircular bearings when this groove is not formed This means a portion (area of a cross section parallel to a plane perpendicular to the bearing axis).

  In still another embodiment of the present invention, the axial groove includes an oil relief and a crush relief formed on a bearing inner peripheral surface adjacent to a butt end surface of the semicircular bearing. Even in the conventional semi-circular bearing, the lubricating oil and foreign matter are discharged outward in the axial direction through the oil relief and the crash relief. However, according to the test results, most of the foreign matter stays in the crash relief. It has been found. In the present embodiment, by providing the axial groove including the oil relief and / or the crush relief, foreign matters that have been apt to stay in the crush relief can be smoothly discharged to the outside of the bearing. Here, “the axial groove includes oil relief and / or crush relief” means that the thickness of both ends of the semicircular bearing on the open side (the butt end with the mating semicircular bearing). The oil relief and the crush relief are formed by making the wall thickness thinner than the thickness of the center portion of the bearing, which means that the depth size of the axial groove is set beyond the amount of thickness reduction due to the oil relief or the crush relief.

  In still another embodiment of the present invention, the circumferential groove and the axial groove are formed symmetrically with respect to the bearing center line (that is, the axis) of the connecting rod in both of the pair of semicircular bearings. Is done. According to this configuration, the number of times that the diametrical through hole of the crank pin repeatedly communicates with the circumferential groove of the connecting rod bearing with the rotation of the crank pin during engine operation is smaller than in the case of a single circumferential groove. The foreign matter flowing in the circumferential groove and the axial groove together with the lubricating oil is efficiently discharged to the outside. When the diametrical through hole of the crank pin communicates with the circumferential groove of the connecting rod bearing, the foreign material in the circumferential groove is smoothly pumped toward the axial groove by the lubricating oil supplied from the diametrical through hole. The

  A connecting rod bearing for an internal combustion engine according to yet another embodiment of the present invention is provided in a circumferential direction from each of two butted end surfaces of a pair of mating semicircular bearings on the inner peripheral surface of one of the semicircular bearings. In the state where two circumferential grooves formed within a range of a maximum circumferential angle of 45 degrees toward the center and the butted end surfaces of the pair of semicircular bearings are butted against each other, the both butted end surfaces And on the inner peripheral surface of at least one of the semicircular bearings over the entire length between both sides parallel to the plane perpendicular to the axis of the connecting rod bearing, the lubricating oil flow path Two axial grooves in communication with each of the two circumferential grooves.

  A connecting rod bearing for an internal combustion engine according to still another embodiment of the present invention includes a central portion in the circumferential direction from each of the two butted end surfaces of the opposite semicircular bearing on the inner peripheral surface of each of the semicircular bearings. The two circumferential grooves formed within a range of a maximum circumferential angle of 45 degrees toward and toward the butted end surfaces of the semicircular bearings are assembled along the butted end surfaces. And formed on the inner peripheral surface of at least one of the semicircular bearings over the entire length between both sides parallel to a plane perpendicular to the axis of the connecting rod bearing, and all the circles as lubricating oil flow paths. And two axial grooves in communication with each of the circumferential grooves.

According to the present invention, the relative rotation of the crank pin with respect to the connecting rod bearing, which is at least one of the two butted end surfaces of the paired counterpart semicircular bearing on the inner peripheral surface of at least one of the semicircular bearings A circumferential groove is formed within a range of a maximum circumferential angle of 45 degrees from the butt end surface on the front side in the direction toward the center in the circumferential direction, and the diameter of the crankpin from the journal portion of the crankshaft during engine operation. Lubricating oil sent via the internal lubricating oil passage leading to the directional through hole is supplied between the crank pin and the connecting rod bearing from the diametric through hole, and together with foreign matter accompanying the lubricating oil, in the rotational direction of the crank pin It smoothly flows in the circumferential groove toward the butt end face side of a pair of semicircular bearings. This flow is aligned with the direction of rotation of the crankpin relative to the connecting rod bearing and facilitates the movement of foreign matter associated with the lubricating oil along the circumferential groove.
Further, in the connecting rod bearing of the present invention, the butted end surfaces of the pair of semicircular bearings are assembled with each other butted along the butted end surface on the side where the circumferential groove is formed, and An axial groove is formed on at least one inner peripheral surface of the semicircular bearings over the entire length between both sides parallel to a plane perpendicular to the axis, and communicates with the circumferential groove as a lubricating oil passage. The circumferential groove and the axial groove are in a T-shaped cross communication, and the lubricating oil flowing in the circumferential groove is a sliding surface portion of the mating semicircular bearing that makes a pair. The direction of flow is changed in the axial groove without heading toward the center, and discharged from the both side portions of the connecting rod bearing to the outside.
Therefore, the object of the present invention is achieved in which foreign matter accompanying the lubricating oil sent from the cylinder block of the internal combustion engine to the connecting rod bearing portion through the journal portion of the crankshaft is quickly discharged from the connecting rod bearing portion to prevent bearing damage. be able to.
Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a schematic diagram in which a crankshaft of an internal combustion engine is cut at a journal portion and a crankpin portion, respectively, and shows a journal 10, a crankpin 12 and a connecting rod 14. The positional relationship of these three members in the depth direction of the paper surface is that the journal 10 is at the farthest side of the paper surface, the crank pin 12 is on the front side, and the crank pin 12 is large on the other end of the connecting rod 14 that carries the piston. Surrounded by an end housing 16.
The journal 10 is supported on the lower part of the cylinder block of the internal combustion engine via a pair of semicircular bearings 18A, 18B. In the semicircular bearing 18A located on the upper side in the drawing, a lubricating oil groove 18a is formed over the entire inner circumferential surface.
Moreover, the journal 10 has the diameter direction through-hole 10a, and if the journal 10 rotates to the arrow X direction, the both-ends opening of the through-hole 10a will communicate with the lubricating oil groove 18a alternately.
Further, a lubricating oil passage 20 is formed in the crankshaft through the journal 10, a crank arm (not shown), and the crankpin 12.

The crankpin 12 is held by a large end housing 16 of the connecting rod 14 via a pair of semicircular bearings 24, 26 (this is composed of a connecting rod side large end housing 16A and a cap side large end housing 16B). ing. The semicircular bearings 24 and 26 are assembled into a cylindrical connecting rod bearing 22 by assembling them with their butted end faces abutting each other. 2 to 4 show details of the semicircular bearings 24 and 26 constituting the connecting rod bearing 22. The semicircular bearing 24 has a circumferential groove 24 </ b> C corresponding to a circumferential length within a circumferential angle of 45 degrees from one of the circumferential end faces 24 </ b> A and 24 </ b> B toward the circumferential central part. Is formed. Further, the circumferential groove 24C is located at the center of the axial length of the semicircular bearing 24 (the length between the axial sides 24a and 24b). In addition, an inclined surface 24D formed by missing a part on the inner peripheral surface side of the end surface 24A of the semicircular bearing 24 over the entire length between both side edges 24a and 24b parallel to a plane perpendicular to the axis of the bearing. Is formed. The inclined surface 24D cooperates with a similar inclined surface 26D formed on the mating semicircular bearing 26 to define an axial groove 24E having a substantially triangular cross section.
In FIG. 1, as a preferred example, inclined surfaces are provided on both circumferential end surfaces 24 </ b> A and 26 </ b> A. However, the inclined surfaces are not necessarily limited to this example, and only at least one of both semicircular bearings is inclined. May be provided.
In FIG. 2, the circumferential groove 24 </ b> C of the semicircular bearing 24 is formed on the end face 24 </ b> A side that is located in front of the rotation direction (arrow Z) of the crankpin 12.
Further, the inclined surface 26D is formed on one end surface 26A side of the circumferential end surfaces 26A, 26B of the semicircular bearing 26.

  Although it is not always necessary to provide a circumferential groove and an axial groove on the other circumferential end face 24B, 26B side of the semicircular bearings 24, 26, FIG. 2 to FIG. The example which provided the circumferential direction groove | channel and the axial direction groove | channel also in the direction end surface 24B, 26B side is shown. The circumferential grooves and the axial grooves are symmetrical about the bearing center line (that is, the axis) of the connecting rod bearing with respect to the circumferential grooves 24C and 24E on the circumferential end faces 24A and 26A. Specifically, they are formed on the circumferential end faces 26B and 24B, and are formed in the circumferential groove 26F and the axial groove 26H defined by the inclined surfaces 26G and 24G. Similarly to the circumferential groove 24C, the circumferential groove 26F is also formed on the end face 26B side of the semicircular bearing 26 that is positioned forward in the rotational direction of the crankpin 12.

Next, the dimensional relationship as an example of the structural member according to the present embodiment is shown below.
(1) Hole diameter of the lubricating oil passage 20 traversing the crankpin 12: 5 to 7 mm.
(2) Width of circumferential grooves 24C and 26F: 1 to 7 mm.
(3) Depth of circumferential grooves 24C and 26F: 0.1 to 0.5 mm (this size takes into account the size of foreign matter). In semi-circular bearings, generally, the thickness of both ends on the open side (the butt end with the mating semi-circular bearing that makes a pair) is thinner than the thickness in the center in the circumferential direction. In this case, an oil relief that gradually becomes thinner and a crush relief that locally thins the thickness of both butted ends are formed. In this case, the depth of the circumferential grooves 24C and 26F is increased. The thickness may be larger than the amount of thickness reduction based on the wall thickness in the center in the circumferential direction due to oil relief or crash relief.
(4) Length of circumferential grooves 24C and 26F: equivalent to a circumferential length of 45 degrees or less from one of the circumferential end faces of the semicircular bearing toward the circumferential center. To do. This angle is determined so as to avoid the fact that the center portion in the circumferential direction of the semicircular bearing 22 is the portion where the load is the largest.
(5) Groove width (L1) of the axial grooves 24E and 26H: less than 2 mm.
(6) Groove depth (L2) of the axial grooves 24E and 26H: 0.1 to 0.5 mm.
(7) Crush relief: The crush relief dimension of the edge portion on the bearing inner peripheral surface side of the circumferential end surfaces 24A, 24B, 26A, and 26B is a circle extending from the butt end surface of the bearing toward the center in the circumferential direction. The circumferential length is 3 mm to 15 mm, and the thickness is 0.01 to 0.05 mm based on the thickness of the central portion in the circumferential direction.

The connecting rod bearing of the present embodiment is configured as described above, and its function will be described below.
Of the pair of semi-circular bearings 18A, 18B constituting the main bearing for supporting the journal 10 from the oil gallery provided in the cylinder block during the operation of the engine, the semi-circular bearing 18A having a lubricating oil groove 18a formed on the inner peripheral surface thereof. Lubricating oil is supplied into the lubricating oil groove 18a through an opening formed through the wall. Openings at both ends of the diametrical through hole 10a formed in the rotating journal 10 are intermittently communicated with the lubricating oil groove 18a. At the time of the communication, lubricating hydraulic pressure acts in the through hole 10a and further communicates with the through hole 10a. Lubricating oil supply pressure also acts on the lubricating oil path 20, and lubricates the sliding surface portion between the crankpin 12 and the connecting rod bearing 22 from the outlet (opening) of the lubricating oil path 20 existing on the outer peripheral surface of the crankpin 12. Oil is supplied. However, when the outlet (opening) of the lubricating oil passage 20 intermittently communicates with the circumferential grooves 24C and 26F according to the rotation of the crankpin 12, a large amount of lubricating oil is contained in the circumferential grooves 24C and 26F. Flows in and foreign matter 28 associated with the lubricating oil and foreign matter 28 already present in the circumferential grooves 24C and 26F are pushed away along the circumferential groove. This flow is ensured by the presence of axial grooves 24E, 26H communicating with the circumferential grooves 24C, 26F. The foreign material 28 that has flown through the circumferential grooves 24C and 26F and reaches the axial grooves 24E and 26H has no circumferential groove in the mating semicircular bearing. It is difficult to flow in, and flows into the axial grooves 24E and 26H exclusively, and is discharged to the outside of the bearing from both sides parallel to the plane perpendicular to the bearing axis.
Further, since the circumferential grooves 24C and 26F exist on the circumferential end face side of the semicircular bearings 24 and 26 on the rotation forward direction side of the crankpin 12, foreign matter in the circumferential grooves 24C and 26F. It tends to promote 28 emissions.

  In this case, if a configuration in which the groove cross-sectional area of the circumferential grooves 24C and 26F is increased from the circumferential center side of the inner circumferential surface toward the butt end surface, lubrication flowing in the circumferential grooves 24C and 26F is adopted. The flow of the oil and the foreign matter 28 becomes gentle toward the butt end face, and the foreign matter 28 in the circumferential groove is surely pushed to the axial groove side along with the flow of the lubricating oil. Further, since the flow velocity of the lubricating oil and the foreign matter 28 when approaching the axial groove is slow, a phenomenon in which the lubricating oil and the foreign matter enter the opposite semicircular bearing side over the axial groove due to inertial force. Can be avoided.

In addition, when a configuration in which the groove cross-sectional area of the circumferential grooves 24C and 26F is larger than the groove cross-sectional area of the axial grooves 24E and 26H is adopted, the inside of the circumferential grooves 24C and 26F can be made relatively gentle. The flow velocity of the lubricating oil and foreign matter increases in the axial grooves 24E and 26H, and is quickly discharged to the outside of the bearing from both sides parallel to the plane perpendicular to the bearing axis.

  In the first embodiment, the semicircular bearing 24 in which the circumferential groove 24C is formed only on the end face 24A side positioned on the arrow Z side that is the rotation direction of the crankpin 12, and the arrow Z side that is the rotation direction of the crankpin 12 The connecting rod bearing 22 combined with the semicircular bearing 26 in which the circumferential groove 26F is formed only on the end face 26B side positioned at the side is introduced. Example 2 (modified example) shown in FIG. Although the effect is somewhat inferior to that of the case, a practically satisfactory foreign matter discharge effect can be obtained. In the second embodiment, a semicircular bearing 30 positioned on the upper side (that is, the connecting rod side large end housing side) and a semicircular bearing 32 positioned on the lower side (that is, the cap side large end housing side) are formed. A connecting rod bearing is used. Here, in each of the semicircular bearings 30 and 32, circumferential grooves 30A, 30B, 32A, and 32B having the same shape as the circumferential grooves 24C and 26F in the first embodiment are formed on the inner surfaces of both ends in the circumferential direction. , And axial grooves (not shown) having the same shape as the axial grooves 24E and 26H in the first embodiment. The connecting rod bearing of this embodiment is not only the circumferential grooves 30A and 32B for sweeping foreign matter into the axial grooves on the rotation forward direction (arrow Z direction) side of the crankpin 12, but also on the counter-rotation direction side of the crankpin 12. Since the circumferential grooves 30B and 32A are also assembled, when the semicircular bearing is assembled to the connecting rod, it is assembled with the circumferential groove positioned only on the end surface on the counter-rotating direction side of the crankpin 12. Errors can be prevented.

  In Example 3 (modification) shown in FIG. 8, the semicircular bearing 34 is located on the upper side (that is, the connecting rod side large end housing side) and the lower side (that is, the cap side large end housing side). A connecting rod bearing formed with a semicircular bearing 36 is used. The semicircular bearing 34 has an inner peripheral surface on which no circumferential groove is formed. The semicircular bearing 36 has circumferential grooves 36A, 36B having the same shape as the circumferential grooves 24C, 26F in the first embodiment, and the axial grooves 24E in the first embodiment, on the inner surfaces of both circumferential ends. It has an axial groove (not shown) of the same shape as 26H. The third embodiment shown in FIG. 8 is slightly inferior to that of the first embodiment, but can obtain a foreign matter discharging effect that is practically satisfactory. The connecting rod bearing of the present embodiment is not only a circumferential groove 36B for sweeping foreign matter into the axial groove on the rotation forward direction (arrow Z direction) side of the crankpin 12, but also a circle on the counterrotation direction side of the crankpin 12. Since it also has the circumferential groove 36A, when assembling the semicircular bearing to the connecting rod, it is possible to prevent an error such that the circumferential groove is located only on the end surface on the counter-rotating direction side of the crankpin 12. Can do. The semicircular bearing located on the upper side (that is, the connecting rod side large end housing side) is a semicircular bearing 36 with a circumferential groove, and the semicircular bearing located on the lower side (that is, the cap side large end housing side). The circular bearing may be a semicircular bearing 34 in which a known lubricating oil groove is not formed along the entire length in the circumferential direction.

Foreign matter discharge property confirmation test Foreign matter discharge property confirmation of connecting rod bearings of Examples 1 to 3, and conventional connecting rod bearings having no circumferential grooves and axial grooves, and connecting rod bearings of Comparative Examples 1 to 3 A test was conducted. Comparative Example 1 is a conventional connecting rod bearing having only an axial groove having the same shape as that of the embodiment, and Comparative Example 2 has a circumferential groove having the same shape as that of Embodiment 2, but the axial line. The connecting rod bearing having no directional groove, Comparative Example 3, was a connecting rod bearing having a circumferential groove having a constant depth and width over the entire circumferential length of the inner peripheral surface but having no axial groove. The test subjects and test conditions are as follows.

  A drive rotating shaft (see Table 2) was supported using a connecting rod bearing of the type shown in Table 1, and the rotating shaft was rotated in a forced lubrication state. The rotating shaft imitates a crank pin, and the lubricating oil was forcibly supplied toward the inner peripheral surface of the test bearing through a lubricating oil passage branched in a radial direction from the center oil hole of the crank pin. At that time, before starting the test, the foreign matter (1 mg) made of fine particles was mixed with and adhered to the inner wall of the lubricating oil passage facing the discharge port (opening) of the lubricating oil passage on the outer peripheral surface of the crankpin. The foreign particles were an iron-based material, and had a major axis = 0.17 to 0.2 mm and a thickness = 0.05 to 0.1 mm. Table 2 shows the test conditions. For the connecting rod bearing to be tested, three test products (N = 3) were prepared for each type and tested.

Test Results After the rotation test for 1 hour each, the number of foreign particles adhered and buried on the inner peripheral surface of the cylindrical bearing consisting of a pair of upper and lower sides was counted. The smaller the number of remaining foreign particles, the better, indicating that more foreign particles are discharged from the bearing together with the lubricating oil. As a result of the test, the average value of the remaining number is as follows: Conventional type = about 280, Example 1 = about 140, Example 2 = about 175, Example 3 = about 160, Comparative Example 1 = about 260, Comparative Example 2 = About 290 and Comparative Example 3 = 320. Here, when the decrease rate of the average number is viewed with the conventional type = about 260 as a reference value (100), Comparative Example 1 = minus 7%, Comparative Example 2 = plus 4%, Comparative Example 3 = plus 14% Example 1 = minus 46%, example 3 = minus 38%, and example 2 = minus 32%. From this result, the foreign matter dischargeability of Example 1 shown in FIGS. 1 to 6 is the best, the foreign matter discharge property of Example 3 shown in FIG. 8 is the next best, and the foreign matter discharge property of Example 2 shown in FIG. It was the third grade. In any case, it was confirmed that a good foreign matter discharging effect of 30% or more was obtained as compared with the conventional type.

The schematic diagram which cut | disconnected the crankshaft of the internal combustion engine in the journal part and the crankpin part, respectively. The cross-sectional view which shows the relationship between the rotating crankpin and a connecting rod bearing. The figure which shows the internal peripheral surface of the upper semicircle bearing of the connecting rod bearing shown in FIG. The figure which shows the internal peripheral surface of the lower semicircle bearing of the connecting rod bearing shown in FIG. FIG. 3 is an enlarged view of a location indicated by an arrow Y in FIG. 2. The figure for demonstrating the dimensional relationship etc. of the upper and lower semicircle bearing shown in FIG. The side view of the connecting rod bearing which concerns on Example 2 of this invention. The side view of the connecting rod bearing which concerns on Example 3 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Journal 10a Diameter through-hole 12 of a journal 12 Crank pin 14 Connecting rod 16 Large end housing 16A Connecting rod side large end housing 16B Cap side large end housing 18A Semicircular bearing 18B Semicircular bearing 18a Lubricating oil groove 20 Lubricating oil path 22 Connecting rod bearing 24 Semicircular bearing 24A Circumferential end surface 24B Circumferential end surface 24C Circumferential groove 24D Inclined surface 24E Axial surface groove 24G Inclined surface 24a Axial side side 24b Axial direction side 26 Semicircular bearing 26A Circumferential end surface 26B circumferential end face 26D inclined surface 26F circumferential groove 26G inclined surface 26H axial groove 28 foreign matter 30 semicircular bearing 30A, 30B circumferential groove 32 semicircular bearing 32A, 32B circumferential groove 34 semicircular bearing 36 semi Circular bearings 36A, 36B Circumference Groove

Claims (7)

Lubricating oil supplied to the inner peripheral surface of the main bearing that supports the crankshaft passes through the inner lubricating oil passage of the crankshaft to the inner peripheral surface of the connecting rod bearing that rotatably supports the crank pin that connects the connecting rod and the crankshaft. A connecting rod bearing for an internal combustion engine configured to be supplied,
The connecting rod bearing comprises a pair of semicircular bearings, one of which is an upper semicircular bearing located on the connecting rod side of the connecting rod large end housing, and the other is a lower semicircle located on the cap side of the connecting rod large end housing. The connecting rod bearing of the type configured as a bearing, wherein the upper semicircular bearing is assembled such that the semicircular circumferential central portion coincides with the central axis of the connecting rod,
At least one of two abutting end surfaces of a paired mating semicircular bearing on the inner peripheral surface of at least one of the semicircular bearings, the thrust on the front side in the relative rotational direction of the crank pin with respect to the connecting rod bearing A circumferential groove formed within a range of a maximum circumferential angle of 45 degrees from the mating end face toward the circumferential central portion;
In a state where the butted end surfaces of the pair of semicircular bearings are butted against each other, they intersect along the butted end surfaces on the side where the circumferential grooves are formed, and intersect the axis of the connecting rod bearing at a right angle. An axial groove formed along the inner peripheral surface of at least one of the semicircular bearings over the entire length between both sides parallel to the plane and communicating with the circumferential groove as a lubricating oil flow path. ,
A groove cross-sectional area of the circumferential groove as viewed from the circumferential direction of the connecting rod bearing in a communication portion between the circumferential groove and the axial groove is a groove of the axial groove as viewed from the axial direction of the connecting rod bearing. It is larger than the cross-sectional area,
A connecting rod bearing for an internal combustion engine, wherein a groove cross-sectional area of the circumferential groove is increased from a circumferential center of the inner circumferential surface toward the butt end surface.   2. The connecting rod bearing for an internal combustion engine according to claim 1, wherein the circumferential groove is formed at a central position between both sides parallel to a plane perpendicular to the axis of the connecting rod bearing.   The connecting rod bearing for an internal combustion engine according to claim 1 or 2, wherein the circumferential groove has a groove width of 1 to 7 mm and a groove depth of 0.1 to 0.5 mm.   The connecting rod bearing for an internal combustion engine according to any one of claims 1 to 3, wherein a groove width of the axial groove is less than 2 mm and a groove depth is 0.1 to 0.5 mm.   The said axial groove | channel contains the oil relief and / or crush relief formed in the bearing internal peripheral surface adjacent to the butt | matching end surface of the said semicircle bearing, Any of Claim 1 to 4 characterized by the above-mentioned. A connecting rod bearing for an internal combustion engine according to claim 1.   6. The circumferential groove and the axial groove are formed symmetrically about the axis of the connecting rod bearing in both of the pair of semicircular bearings. A connecting rod bearing for an internal combustion engine according to any one of the preceding claims. Lubricating oil supplied to the inner peripheral surface of the main bearing that supports the crankshaft passes through the inner lubricating oil passage of the crankshaft to the inner peripheral surface of the connecting rod bearing that rotatably supports the crank pin that connects the connecting rod and the crankshaft. A connecting rod bearing for an internal combustion engine configured to be supplied,
The connecting rod bearing comprises a pair of semicircular bearings, one of which is an upper semicircular bearing located on the connecting rod side of the connecting rod large end housing, and the other is a lower semicircle located on the cap side of the connecting rod large end housing. The connecting rod bearing of the type configured as a bearing, wherein the upper semicircular bearing is assembled such that the semicircular circumferential central portion coincides with the central axis of the connecting rod,
Abutting on the front side in the relative rotational direction of the crank pin with respect to the connecting rod bearing, which is one of two abutting end faces of a paired mating semicircular bearing on the inner peripheral surface of at least one of the semicircular bearings A circumferential groove formed within a range of a maximum circumferential angle of 45 degrees from the end surface toward the circumferential central portion;
In a state where the butted end surfaces of the pair of semicircular bearings are butted against each other, they intersect along the butted end surfaces on the side where the circumferential grooves are formed, and intersect the axis of the connecting rod bearing at a right angle. An axial groove formed along the inner peripheral surface of at least one of the semicircular bearings over the entire length between both sides parallel to the plane and communicating with the circumferential groove as a lubricating oil flow path. ,
A groove cross-sectional area of the circumferential groove as viewed from the circumferential direction of the connecting rod bearing in a communication portion between the circumferential groove and the axial groove is a groove of the axial groove as viewed from the axial direction of the connecting rod bearing. It is larger than the cross-sectional area,
A connecting rod bearing for an internal combustion engine, wherein a groove cross-sectional area of the circumferential groove is increased from a circumferential center of the inner circumferential surface toward the butt end surface.

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