JP2009264465A - Thrust bearing structure for crankshaft - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thrust bearing structure for a crankshaft, using an adequate-size thrust bearing for bearing a thrust load with a relative wide area when a crank arm part is elastically deformed. <P>SOLUTION: The thrust bearing structure for the crankshaft 3 is applied for a V-type internal combustion engine 1 which includes the crankshaft 3 provided with a plurality of piston connection parts 6 paired with a plurality of cylinders 4, respectively. It includes the semi-circular thrust bearing 13 arranged on a bearing part 10 rotatably supporting a journal part 5 of the crankshaft 3, for bearing a thrust load F2 of the crankshaft 3. The thrust bearing 13 and an axial line AX of the cylinder 4 paired with the piston connection part 6 opposed to the thrust bearing 13 are inclined to a bisector BI of the bank angle of the V-type internal combustion engine 1 in the same direction. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a crankshaft thrust bearing structure applied to a V-type internal combustion engine.

  As a thrust bearing structure for the crankshaft, a semicircular thrust bearing is arranged on each of the cylinder block side and the crank bearing cap side of the bearing portion that rotatably supports the crankshaft, and the thrust bearing of the crankshaft is provided by the thrust bearing. Have been known (see, for example, Patent Document 1). In addition, Patent Documents 2 to 6 exist as prior art documents related to the present invention.

Japanese Utility Model Publication No. 5-67814 Japanese Patent Laid-Open No. 2004-19800 Japanese Patent Laid-Open No. 11-108038 JP-A-5-60124 JP 2003-148456 A Japanese Patent Laid-Open No. 8-121459

  In an internal combustion engine with high in-cylinder pressure, such as a high-powered gasoline engine with a supercharger or a diesel engine, the crank arm part moves in the axial direction due to the combustion load input from the piston to the crank pin part via the connecting rod. There is a case where the elastic bearing is instantaneously deformed so as to be spread and a high peak thrust load is input to the thrust bearing along with the deformation. In order to receive the high peak load with a thrust bearing of an appropriate size, a semicircular thrust bearing may be disposed only on the cylinder block side of the bearing portion. However, when such a bearing structure is applied to a V-type internal combustion engine, the input position of the thrust load accompanying the elastic deformation of the crank arm portion is shifted in the circumferential direction of the crankshaft as compared with the in-line internal combustion engine. The area of the thrust bearing that can be received may be relatively narrow.

  Accordingly, the present invention provides a crankshaft thrust bearing structure capable of receiving a thrust load when a crank arm portion is elastically deformed in a relatively wide area while using a thrust bearing of an appropriate size. Objective.

  The thrust bearing structure of the present invention is applied to a V-type internal combustion engine having a crankshaft provided with a plurality of piston coupling portions so as to be paired with a plurality of cylinders, and the journal portion of the crankshaft is freely rotatable. A thrust bearing structure for a crankshaft in which a semicircular thrust bearing that receives a thrust load of the crankshaft is disposed in a bearing portion that supports the thrust shaft, the thrust bearing, and a piston coupling portion that faces the thrust bearing, The axis of the paired cylinders is inclined in the same direction with respect to the bisector of the bank angle of the V-type internal combustion engine (Claim 1).

  According to the thrust bearing structure of the present invention, the semicircular thrust bearing and the axis of the cylinder paired with the piston coupling portion facing the thrust bearing are bisected by the bank angle of the V-type internal combustion engine. They are tilted in the same direction. When a thrust load is generated due to momentary elastic deformation so that the crank arm is pushed and expanded in the axial direction by the combustion load in the cylinder, the load input position is the cylinder axis relative to the bisector. Shift to the side. Therefore, when such a thrust load is generated, the area of the crankshaft in contact with the thrust bearing is relatively wide as compared with the case where the thrust bearing is not inclined with respect to the bisector. Thereby, the thrust load when the crank arm portion is elastically deformed can be received in a relatively wide area. In the present invention, the V-type internal combustion engine includes a W-type internal combustion engine and a horizontally opposed internal combustion engine.

  In one form of the thrust bearing structure of the present embodiment, the thrust bearing and the axis of the cylinder paired with the piston coupling portion facing the thrust bearing are inclined at the same angle with respect to the bisector. Good (claim 2). According to this embodiment, the thrust bearing and the cylinder axis are inclined by the same angle, so that the crank arm is instantaneously elastically deformed so as to be expanded in the axial direction by the combustion load in the cylinder. When a thrust load is generated, the area that can receive the thrust load can be further expanded.

  In one form of the thrust bearing structure of the present embodiment, the piston coupling portion includes a crankpin portion and a crank arm portion that couples the crankpin portion and the journal portion, and the thrust bearing includes the crank arm. It may be provided so that it may contact a part (Claim 3). According to this embodiment, when the crank arm portion is elastically deformed so as to be expanded in the axial direction by a load during combustion, the crank arm portion can be brought into contact with the thrust bearing and the thrust load can be received by the bearing portion.

  As described above, according to the thrust bearing structure of the present invention, the semicircular thrust bearing and the axis of the cylinder paired with the piston coupling portion facing the thrust bearing are connected to the bank of the V-type internal combustion engine. It is inclined in the same direction with respect to the angle bisector. When a thrust load is generated due to momentary elastic deformation so that the crank arm is pushed and expanded in the axial direction by the combustion load in the cylinder, the load input position is the cylinder axis relative to the bisector. Shift to the side. Therefore, when such a thrust load is generated, the area of the crankshaft in contact with the thrust bearing is relatively wide as compared with the case where the thrust bearing is not inclined with respect to the bisector. Thereby, the thrust load when the crank arm portion is elastically deformed can be received in a relatively wide area. Therefore, the fatigue resistance of the thrust bearing can be improved.

  FIG. 1 shows a main portion of an internal combustion engine to which a crankshaft thrust bearing structure according to an embodiment of the present invention is applied. An internal combustion engine (hereinafter sometimes referred to as an engine) 1 is mounted on a vehicle (not shown) as a driving power source, and a pair of banks 2R and 2L are inclined around a crankshaft 3 by an appropriate bank angle. It is formed as an arranged V-type engine. Each bank 2R, 2L is provided with three cylinders 4 respectively. FIG. 1 shows only a part of the plurality of cylinders 4. Hereinafter, the right cylinder in the figure may be described as being distinguished from the first cylinder 4R and the left cylinder as being the second cylinder 4L. In addition, “R” meaning that it corresponds to the first cylinder 4R and “L” meaning that it corresponds to the second cylinder 4L are added to the reference numerals of the respective constituent members as necessary. is there. These characters are omitted when it is not necessary to distinguish between left and right.

  FIG. 2 shows a partially enlarged view of the crankshaft 3. As shown in FIG. 2, the crankshaft 3 includes a journal portion 5 disposed on the rotation center line CL of the crankshaft 3, a first piston coupling portion 6 </ b> R that forms a pair with the first cylinder 4 </ b> R, and a second cylinder. A second piston coupling portion 6L that is paired with 4L is provided. Each piston connecting portion 6 is provided with a crankpin portion 7 that is eccentric with respect to the journal portion 5 and a crank arm portion 8 that connects the journal portion 5 and the crankpin portion 7. The crank arm portion 8 includes a balance weight 9. The journal portion 5 is rotatably supported by the bearing portion 10 on the cylinder block side. A bearing metal is provided between the bearing portion 10 and the journal portion 5, but the illustration thereof is omitted. A connecting rod (not shown) is rotatably attached to the crankpin portion 7.

  Returning to FIG. 1, the description will be continued. The bearing portion 10 is configured by fixing a crank bearing cap 12 to a crank receiving portion 11a formed at the lower portion of the cylinder block 11 with a bolt (not shown). Further, as shown in FIG. 2, on the surface of the bearing portion 10, the first thrust bearing 13R is opposed to the crank arm portion 8R of the first piston coupling portion 6R, and the crank arm of the second piston coupling portion 6L. Second thrust bearings 13L are provided so as to face the portion 8L. Each thrust bearing 13 is formed in a semicircular shape from various materials used for bearing metal (see also FIG. 1). However, when the crankshaft 3 is not deformed, the protrusion amount of the surface of the thrust bearing 13 may be set so that an appropriate gap is provided between the surface of the thrust bearing 13 and the crank arm portion 8.

  As shown in FIG. 1, the first thrust bearing 13R is inclined by the same angle in the same direction as the axis AX1 of the first cylinder 4R with respect to the bisector BI of the bank angle. That is, the first thrust bearing 13R is arranged such that a straight line that bisects the first thrust bearing 13R in the circumferential direction coincides with the axis AX1 of the first cylinder 4R. Similarly, the second thrust bearing 13L is inclined by the same angle in the same direction as the axis AX2 of the second cylinder 4L with respect to the bank angle bisector BI.

  Next, the operation of the thrust bearing structure of the present embodiment will be described with reference to FIGS. 3 shows a state in which the crank arm portion 8R of the first piston coupling portion 6R in FIG. 2 is elastically deformed in the direction of the rotation center line CL of the crankshaft 3. Here, the first thrust bearing 13R will be described as an example, but the same applies to the second thrust bearing 13L. When combustion occurs in the first cylinder 4R, the crank pin portion 7R of the first piston coupling portion 6R is located on the axis AX1 of the first cylinder 4R. When the piston is pushed down by the combustion pressure in the first cylinder 4R, the load F1 acts on the crankpin portion 7R. Due to the load F1, the crank arm portion 8R is instantaneously elastically deformed so as to be expanded in the direction of the rotation center line CL, and a thrust load F2 in the direction of the rotation center line CL is generated. The input position of the thrust load F2 is shifted to the axis AX1 side of the first cylinder 4R with respect to the bisector BI of the bank angle. The thrust load F2 is received by the bearing portion 10 when the crank arm portion 8R comes into contact with the first thrust bearing 13R. At this time, since the first thrust bearing 13R is inclined in the same direction as the axis AX1 of the first cylinder 4R with respect to the bisector BI of the bank angle, the area of the crank arm portion 8R in contact with the first thrust bearing 13R is increased. The first thrust bearing 13R is wider than the case where the first thrust bearing 13R is not tilted. Thereby, the thrust load F2 can be received in a relatively large area. Therefore, the fatigue resistance of the thrust bearing 13 can be improved.

  In the thrust bearing structure of the present embodiment, the first thrust bearing 13R is inclined with respect to the bank angle bisector BI by the same angle as the axis AX1 of the first cylinder 4R, so that the area capable of receiving the thrust load F2 is obtained. Can be expanded more.

  In this embodiment, the thrust bearings 13 are provided at the two bearing portions 10. However, the thrust bearing 13 may be provided only at one of the bearing portions 10, or each of the plurality of bearing portions 10 (not shown). A thrust bearing 13 may be provided. In the latter case, the thrust bearings 13 are arranged so as to be inclined alternately.

  This invention is not limited to the form mentioned above, It can implement with a various form. The inclination angle of the thrust bearing 13 is not limited to the above-described example, and can be appropriately changed. For example, even when the inclination angle of the thrust bearing 13 is set to an angle equal to or less than half the bank angle, the thrust load F2 is generated due to the momentary elastic deformation so that the crank arm portion 8 is expanded in the direction of the rotation center line CL. In this case, the contact area between the crankshaft 3 and the thrust bearing 13 can be made relatively wide as compared with the case where the thrust bearing 13 is not inclined with respect to the bisector BI of the bank angle. The present invention is not limited to an example in which the number of cylinders 4 in each bank 2 is applied to three V-type engines, but can also be applied to a V-type engine in which the number of cylinders 4 in each bank 2 is changed. For example, the present invention can be applied to a V-type 4-cylinder engine, a V-type 8-cylinder engine, and the like. The present invention can also be applied to a W-type engine and a horizontally opposed engine.

The figure which showed the principal part of the internal combustion engine to which the thrust bearing structure of the crankshaft which concerns on one form of this invention was applied. The partial enlarged view of a crankshaft. The figure which showed the state which the crank arm part of the 1st piston connection part in FIG. 2 elastically deformed in the rotation center line direction of the crankshaft.

Explanation of symbols

2R, 2L Bank 3 Crankshaft 4R 1st cylinder 4L 2nd cylinder 5 Journal part 6R 1st piston connecting part 6L 2nd piston connecting part 7R, 7L Crankpin part 8R, 8L Crank arm part 10 Bearing part 13R First thrust bearing 13L Second thrust bearing CL Crankshaft rotation center line AX Cylinder axis

Claims (3)

Applied to a V-type internal combustion engine having a crankshaft provided with a plurality of piston coupling parts so as to be paired with each of a plurality of cylinders, the bearing part rotatably supporting the journal part of the crankshaft, A crankshaft thrust bearing structure in which a semicircular thrust bearing that receives the thrust load of the crankshaft is disposed,
The thrust of the crankshaft in which the thrust bearing and the axis of the cylinder paired with the piston coupling portion facing the thrust bearing are inclined in the same direction with respect to the bisector of the bank angle of the V-type internal combustion engine Bearing structure.   2. The thrust bearing structure for a crankshaft according to claim 1, wherein the thrust bearing and an axis of a cylinder that forms a pair with a piston coupling portion facing the thrust bearing are inclined at the same angle with respect to the bisector. . The piston connecting part has a crankpin part, and a crank arm part that connects the crankpin part and the journal part,
The thrust bearing structure for a crankshaft according to claim 1 or 2, wherein the thrust bearing is provided so as to be in contact with the crank arm portion.

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