JP5157966B2 - Connecting rod support structure - Google Patents

Description

  In the present invention, two connecting rods are supported axially adjacent to each other in the crank pin of a crankshaft of a V-type engine, and a split bearing is interposed between each of the two connecting rods and the crank pin. Related to the structure. More specifically, the present invention relates to an improvement in a split bearing.

  For example, there is a V-type engine as an internal combustion engine mounted on a vehicle such as an automobile. In such a V-type engine, there are cases where two connecting rods are supported by one crankpin in a crankshaft ( For example, see Patent Document 1.)

  In such a case, two split bearings are interposed between the crankpin and the two connecting rods.

  This two-part sliding bearing is formed into a cylindrical shape that is short in the axial direction as a whole by tying together a pair of semi-cylindrical members.

  The upper semi-cylindrical member is fitted and fixed to the concave surface of the connecting rod at the large end, and the lower semi-cylindrical member is bolted to the large end of the connecting rod. It is fitted and fixed to the concave surface. As a result, sliding contact occurs between the outer peripheral surface of the crankpin and the inner surfaces of the pair of semi-cylindrical members.

  In such a configuration, oil is supplied to the sliding contact surface. However, if foreign matter is mixed in the oil, the foreign matter may enter the sliding contact surface. If foreign matter has entered the sliding contact surface for a long time in this way, there is a risk of damaging the outer peripheral surface of the crankpin and the inner surface of the sliding bearing.

  By the way, in the pair of semi-cylindrical members constituting the slide bearing as described above, chamfering is provided on the inner diameter side of each mating surface in the circumferential direction, for the entire axial direction (see, for example, Patent Document 2). . In the case of this conventional example, the width of the chamfer in the radial direction is constant over the entire length in the axial direction.

  When such a slide bearing is incorporated between the crank pin and each of the two connecting rods, a space having a substantially triangular cross section is formed by the outer peripheral surface of the crank pin and the chamfers of the pair of semi-cylindrical members constituting each set of the slide bearing. Is made.

  For this reason, when the foreign substance in oil enters into the sliding contact surface of a crankpin and a sliding bearing etc., the effect | action that this foreign substance will be discharged | emitted outside through the said triangular space is expectable.

JP 2008-144932 A JP 2008-95858 A

  In the conventional example according to Patent Document 2, it is pointed out that the effect of discharging foreign matter by chamfering the slide bearing is insufficient.

  In other words, when two connecting rods are attached to one crankpin, for example, in a V-type engine, in the unlikely event that there is a foreign object together with oil on the sliding contact surface between the crankpin and one of the slide bearings. When the foreign material enters, the foreign matter is not immediately discharged to the outside but moves to the axial alignment portion of the two sets of slide bearings, and then the other set of slide bearings located next to the one set of slide bearings. It can happen that the sliding contact surface with the crankpin enters.

  Moreover, in the case of the conventional example, even if foreign matter enters the triangular space, whether or not the foreign matter moves outward is determined because of the relationship that the chamfered radial width is constant over the entire length in the axial direction. It is pointed out that the moving direction of the foreign matter is not fixed, such as unknown. Therefore, it can be said that the foreign matter cannot be excluded from the sliding contact surface as described above. There is room for improvement here.

  In the present invention, two connecting rods are supported axially adjacent to each other in the crank pin of a crankshaft of a V-type engine, and a split bearing is interposed between each of the two connecting rods and the crank pin. Even if foreign matter enters the sliding contact surface between the crank pin and one set of sliding bearings together with oil, the foreign matter should not move to the sliding contact surface between the crank pin and the other sliding bearing. The purpose is to make it possible to quickly eliminate it to the outside.

  In the present invention, two connecting rods are supported axially adjacent to each other in the crank pin of a crankshaft of a V-type engine, and a split bearing is interposed between each of the two connecting rods and the crank pin. In the pair of semi-cylindrical members constituting the slide bearing, chamfers are respectively provided at the inner diameter side corners of the respective mating surfaces in the circumferential direction along the entire axial direction. The width in the direction is set to gradually increase from the mating portion of the two adjacent slide bearings toward the outside in the axial direction.

  In this configuration, when the slide bearing is assembled between the crank pin and the two connecting rods, a space having a substantially triangular cross section is created by the outer peripheral surface of the crank pin and the chamfers of the pair of semi-cylindrical members constituting the slide bearing. Will be.

  In addition, when the width in the radial direction of the chamfer is gradually increased toward the outer side in the axial direction, the chamfer becomes a surface that is gradually inclined toward the outer end side from the inner end side in the axial direction.

  As a result, even if foreign matter enters the sliding contact surface between the crank pin and the one pair of sliding bearings together with oil, if the foreign matter enters the triangular space, the flow pressure of oil acting on the foreign matter and Due to the centrifugal force accompanying the eccentric rotation of the crankpin, the foreign matter is sent out in the axial direction along the inclined chamfer.

  As described above, the chamfering provided on the mating surfaces in the circumferential direction in the pair of semi-cylindrical members that respectively constitute the two sets of plain bearings is a surface that gradually and greatly inclines toward one side in the axial direction. In cooperation with the flow pressure of the cylinder and the centrifugal force associated with the eccentric rotation of the crank pin 1b, it is possible to obtain the action of sending out the foreign matter to the outside in the axial direction of the two sets of slide bearings, thereby quickly discharging the foreign matter to the outside. It becomes possible.

  Preferably, the chamfer is a flat surface. In this case, the action of feeding out the foreign matter can be obtained more reliably.

  In the present invention, two connecting rods are supported axially adjacent to each other in the crank pin of a crankshaft of a V-type engine, and a split bearing is interposed between each of the two connecting rods and the crank pin. Even if foreign matter enters the sliding contact surface between the crank pin and one set of sliding bearings together with oil, the foreign matter should not move to the sliding contact surface between the crank pin and the other sliding bearing. It becomes possible to eliminate it quickly to the outside.

  As a result, it is possible to avoid damage to the outer peripheral surface of the crankpin and the inner surface of the sliding bearing for the connecting rod, and it is possible to stably support the connecting rod for a long period of time.

FIG. 5 is a cross-sectional view showing the vicinity of one crank pin of a crankshaft in an embodiment of a connecting rod support structure according to the present invention. It is an arrow view of the (2)-(2) line cross section of FIG. It is an arrow view of the (3)-(3) line cross section of FIG. It is a figure which expands and shows the principal part of FIG. 1, and is a figure used in order to demonstrate the exclusion effect | action of a foreign material. It is a perspective view which shows only two sets of slide bearings used for support of the connecting rod of FIG.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, the best mode for carrying out the invention will be described in detail with reference to the accompanying drawings.

  1 to 5 show an embodiment of the present invention. Here, a V-type 8-cylinder engine mounted on a vehicle such as an automobile is an application target of the present invention.

  In the figure, 1 is a crankshaft. The crankshaft 1 includes a large number of crank journals 1a and a large number of crank pins 1b arranged between adjacent crank journals 1a. FIG. 1 shows a part of the crank journal 1a and the crankpin 1b.

  Each crank journal 1 a is rotatably supported by a cylinder block 2 and a crank cap 3 via a slide bearing 4.

  Large end portions 5a and 6a of the first connecting rod 5 and the second connecting rod 6 are rotatably supported by the crankpins 1b via the slide bearings 7 and 8, respectively. These first and second connecting rods 5 and 6 are arranged adjacent to each other in the axial direction.

  Further, as shown in FIG. 3, the first and second connecting rods 5 and 6 are, when viewed from the front side of the crankshaft 1 (left side in the figure), a vertical line L passing through the axis of the crankpin 1b. Is inclined to correspond to the bank angle (for example, 90 degrees) of the V-type 8-cylinder engine.

  Although not shown, a piston is connected to each small end (upper end) of the first and second connecting rods 5 and 6, and each piston is accompanied by an explosion in a combustion chamber not shown. The connecting rods 5 and 6 are moved down and reciprocated so that the crank pin 1b rotates eccentrically.

  The crank journal sliding bearing 4 and the connecting rod sliding bearings 7 and 8 are all divided into two parts, and are joined together to form a short cylindrical shape in the axial direction as a whole.

  As shown in FIG. 2, in the crank journal slide bearing 4, the upper semicylindrical member 4a is fitted and fixed to the concave surface of the cylinder block 2, and the lower semicylindrical member 4b is a cylinder block. 2 is fitted and fixed to the concave surface of the crank cap 3 which is bolted to 2. As a result, sliding contact occurs between the outer peripheral surface of the crank journal 1a and the inner surfaces of the pair of semi-cylindrical members 4a and 4b.

  On the other hand, as shown in FIG. 3, in the sliding rod bearings 7 and 8, the upper semi-cylindrical members 7 a and 8 a are fitted and fixed to the concave surfaces of the large ends 5 a and 6 a of the connecting rods 5 and 6. The lower-side semicylindrical members 7b and 8b are fitted and fixed to the concave surfaces of the large end caps 9 and 9, respectively. As a result, sliding contact occurs between the outer peripheral surface of the crankpin 1b and the inner surfaces of the pair of semi-cylindrical members 7a, 7b, 8a, 8b. In FIG. 3, one of the plain bearings 8 is not visible.

  Therefore, these slide bearings 4, 7, and 8 are formed of an appropriate metal, resin, or the like that is generally used for known slide bearings. Further, oil is supplied between the slide bearing 4 and the crank journal 1a and between the slide bearings 7 and 8 and the crank pin 1b. This oil supply path will be described below.

  That is, the cylinder block 2 is provided with a passage 9a communicating with a main journal (not shown). The crank journal 1a is provided with a through hole 9b penetrating in the radial direction and an oblique communication hole 9c. The crank pin 1b is provided with slanted inclined holes 9d and 9e.

  The oil supplied to the main journal is sent from the passage 9a to the through hole 9b and then supplied between the crank journal 1a and the crank journal slide bearing 4, and the communication hole 9c and the inclined hole are provided. Supplied between the crankpin 1b and the crankpin sliding bearings 7 and 8 through 9d and 9e.

  As shown in FIGS. 1 and 2, a groove 4 c is provided in an axially intermediate region on the inner surface of the upper-side semicylindrical member 4 a of the crank journal slide bearing 4. The groove 4c serves as a relay path for communicating the passage 9a of the cylinder block 2 and the through hole 9b of the crank journal 1a.

  Generally, chamfers 7c, 7d, 8c, and 8d are provided at the inner diameter side corners of the mating surfaces of the pair of semi-cylindrical members 7a, 7b, 8a, and 8b constituting the sliding bearings 7 and 8 for the connecting rod, respectively. Are provided along the entire length in the axial direction.

  The chamfers 7c, 7d, 8c, and 8d are formed on a flat surface, and the radial width of the chamfers 7c, 7d, 8c, and 8d is directed outward in the axial direction from the axially aligned portions of the two adjacent slide bearings 7 and 8. Is set to gradually increase.

  As described above, when the radial widths of the chamfers 7c, 7d, 8c, and 8d are gradually increased outward in the axial direction, the chamfers 7c, 7d, 8c, and 8d are moved from the inner side in the axial direction to the outer side. The surface gradually slopes toward the surface.

  In FIG. 4, in order to make it easy to see the chamfers 7c and 8c, for convenience, the circumferential end surfaces of the upper-side semicylindrical members 7a and 8a are arranged above and below the crankpin 1b. . Actually, as described above, the upper-side semicylindrical members 7a and 8a are fitted and fixed to the concave surfaces of the large end portions 5a and 6a of the connecting rods 5 and 6, and the lower-side semicylindrical shape. Since the members 7b and 8b are fitted and fixed to the concave surfaces of the large end caps 9 and 9, the circumferential alignment surfaces of the pair of semi-cylindrical members 7a, 7b, 8a and 8b are in the state shown in FIG. Become.

  The chamfers 7c, 7d, 8c, and 8d that are inclined in this way will be described in detail later. When foreign matter enters the sliding contact surface between the crank pin 1b and the sliding rod sliding bearings 7 and 8 together with oil. In addition, it plays a role of quickly discharging the foreign matter.

  Therefore, the radial widths of the chamfers 7c, 7d, 8c, and 8d are set as appropriate by experiments or the like so that the size of foreign matter that may be mixed into the oil is taken into consideration so that the foreign matter can be removed. The

  Incidentally, as the foreign matter as described above, for example, sludge in oil, worn parts of each part, or chips formed when the through hole 9b or the communication hole 9c is formed in the crank journal 1a of the crankshaft 1 or the inclination of the crank pin 1b. Chips and the like for forming the holes 9d and 9e can be considered. The chips may remain in the holes 9b to 9e when the crankshaft 1 is manufactured. Normally, although the chips are removed by cleaning the crankshaft 1 as a single item, it cannot be said that there is no possibility that the chips remain in the holes 9b to 9e.

  Here, the operation of the chamfers 7c, 7d, 8c, and 8d will be described.

  In the first place, in the state where the slide bearings 7 and 8 are incorporated between the crankpin 1b and the two connecting rods 5 and 6, for example, as shown in FIG. 3, the outer peripheral surface of the crankpin 1b and the slide bearings 7 and 8 are provided. A space having a substantially triangular cross section is created by the chamfers 7c, 7d, 8c, 8d of the pair of semi-cylindrical members 7a, 7b, 8a, 8b.

  For example, oil is supplied to the sliding contact surfaces between the crank pin 1b and the connecting rod sliding bearings 7 and 8 through the holes 9a to 9e, and foreign matter may be mixed in the oil. When this foreign matter moves from the sliding contact surface into the triangular space, for example, as shown in FIG. 4, the foreign matter 20 located on the narrow side (the axial inner end side) of the chamfers 7c, 7d, 8c, and 8d. However, by receiving the oil flow pressure, the centrifugal force 21 accompanying the eccentric rotation of the crank pin 1b, etc., the oil is guided to the inclined chamfers 7c, 7d, 8c, 8d, and in the direction of the arrow 22, that is, the chamfers 7c, 7d. , 8c, 8d are fed toward the wide side (the outer end side in the axial direction).

  In this way, the chamfers 7c, 7d, 8c, and 8d provided on the mating surfaces in the circumferential direction in the pair of semi-cylindrical members 7a, 7b, 8a, and 8b constituting the slide bearings 7 and 8 are moved to one axial direction. The chamfers 7c, 7d, 8c, and 8d cooperate with the oil flow pressure, the centrifugal force accompanying the eccentric rotation of the crank pin 1b, and the like, so that two sets of foreign substances 20 are formed. Thus, the bearings 7 and 8 are fed out in the axial direction. As a result, the foreign matter 20 can be quickly removed from the sliding contact surface between the crank pin 1b and the sliding bearings 7 and 8 to the outside. The foreign matter 20 thus excluded outside is taken into an oil filter or the like (not shown).

  Therefore, the outer peripheral surface of the crankpin 1b and the inner surfaces of the sliding bearings 7 and 8 for the connecting rods 5 and 6 are prevented from being damaged, and the connecting rods 5 and 6 are stably supported over a long period of time. Is possible.

  In addition, this invention is not limited only to the said embodiment, All the deformation | transformation and application included in the range equivalent to the claim and the said range are possible. Examples are given below.

  For example, in the above-described embodiment, a case where a 90-degree bank V-type 8-cylinder engine is applied as an example of application of the present invention is described as an example, but in short, two connecting rods 5 and 6 are axially connected to one crankpin 1b. As long as the type is supported side by side, the number of cylinders and the bank angle are not particularly limited.

  Further, for example, in the above embodiment, the case where the chamfers 7c, 7d, 8c, and 8d of the slide bearings 7 and 8 provided adjacent to each other are flat surfaces is exemplified. However, a curved surface that is round and recessed may be used. It is.

DESCRIPTION OF SYMBOLS 1 Crankshaft 1a Crank journal 1b Crankpin 5 1st connecting rod 6 2nd connecting rod 7, 8 Slide bearing 7a, 8a Upper side semi-cylindrical member 7b, 8b Lower side semi-cylindrical member 7c, 8c Upper side semi-cylindrical shape Chamfering of member 7d, 8d Chamfering of lower semi-cylindrical member

Claims (2)

Two connecting rods are supported axially next to each other on the crank pin of the crankshaft of the V-type engine, and a split bearing is interposed between each of the two connecting rods and the crank pin. And
In the pair of semi-cylindrical members constituting the slide bearing, chamfers are provided on the inner diameter side corners of the mating surfaces in the circumferential direction, respectively, in the axial length.
A connecting rod support structure characterized in that the radial width of the chamfer is gradually increased from the mating portion of the two adjacent sets of slide bearings toward the outside in the axial direction. The connecting rod support structure according to claim 1,
The connecting rod support structure according to claim 1, wherein the chamfer is a flat surface.

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