JP5396312B2 - Crankshaft thrust bearing structure - Google Patents

Description

  The present invention relates to a thrust bearing structure for a crankshaft.

  2. Description of the Related Art Conventionally, some crankshafts of automobile engines have a pulley to which an endless transmission member such as a timing belt is hung fixed at one end and a flywheel is fixed coaxially to the other end. In such a crankshaft, there is a risk that the flywheel will run out due to the impact force of the explosion stroke, and vibration due to deflection may occur in the crankshaft due to the face runout. There is one in which a thrust metal is provided in a bearing portion adjacent to a flywheel to suppress bending of the crankshaft (see, for example, Patent Document 1).

Microfilm of actual application No.59-23391

  However, some transmissions are coupled to the flywheel side of the crankshaft, and a large thrust load may be applied from the transmission. However, in Patent Document 1, a metal bearing is used as the thrust bearing. Therefore, there is a problem that the driving resistance of the crankshaft cannot be reduced for a large thrust load.

  Further, as described above, when an endless transmission member is wound around one end side of the crankshaft via a pulley, bending vibration is generated on the crankshaft on the side opposite to the flywheel side. In the thing of the said patent document 1, the thrust bearing was arrange | positioned at the flywheel side of the crankshaft, and there existed a problem that the bending vibration produced on the side contrary to the flywheel side could not be suppressed.

In order to solve such problems and to further reduce the driving resistance against the thrust load of the crankshaft and further suppress the bending vibration, the present invention provides an engine body (E). And a transmission rotating member (3) integrally supported by a plurality of bearings (8) disposed in the shaft and having an endless transmission member (5) wound around one end in the axial direction. And a crankshaft thrust bearing structure having a crankshaft (1) having a transmission (4) connected to the other end in the axial direction, wherein the plurality of bearings (8) are respectively supported by the engine body (E). A plurality of bearing support portions (6a to 6d) are provided, and one end side bearing support portion (6a) at a position closest to the transmission rotation member (3) of the plurality of bearing support portions (6a to 6d); Said Thrust roller bearing (9) is provided for receiving the thrust load of the crank shaft (1) between the faces on one end side bearing support portion (6a) faces of the link shaft (1), said plurality of bearing Between the adjacent bearing support part (6b) adjacent to the one end side bearing support part (6a) of the support part (6a to 6d) and the surface facing the adjacent bearing support part (6b) of the crankshaft (1) It is assumed that a thrust sliding bearing (11) for receiving a thrust load of the crankshaft (1) is provided .

  According to this, in the case where bending vibration is generated in the crankshaft due to the load transmitted from the endless transmission member via the transmission rotation member, the transmission rotation member is the most among the plurality of bearing support portions that support the crankshaft. Since the thrust roller bearing is arranged between the one near the crankshaft and the crankshaft, the distance between the rotating member for transmission and the thrust roller bearing is short. Vibration can be suppressed. Further, even if the axial load from the transmission side increases, the thrust load can be received by the thrust roller bearing, and the driving resistance of the crankshaft can be reduced more than in the case of the thrust slide bearing.

  In particular, the adjacent bearing support portion (6b) adjacent to the one end side bearing support portion (6a) of the plurality of bearing support portions (6a to 6d) and the adjacent bearing support portion (6b) of the crankshaft (1). A thrust slide bearing (11) for receiving a thrust load of the crankshaft (1) is preferably provided between the opposing surfaces. According to this, in the case where the engine body and the crankshaft are made of different materials, a difference in thermal expansion occurs between the bearing support portion provided with the thrust bearing and the portion corresponding to the thrust bearing of the crankshaft so that there is a gap. However, if the bearing support part provided with the thrust roller bearing and the bearing support part provided with the thrust slide bearing are adjacent to each other and the distance between the two thrust bearings is one cylinder, the distance can be minimized. , Increase in the thermal expansion difference can be suppressed.

  The thrust slide bearing (11) is provided in a semi-annular shape on the piston (2) side with respect to the crankshaft (1), and the piston (2) side of the adjacent bearing support portion (6b) is defined as On the opposite side, there are both circumferential end faces (13a) for supporting both ends in the circumferential direction of the thrust slide bearing (11), and on the side opposite to the thrust slide bearing (11) of the crankshaft (1). Protrusions (13, 14) having an inner wall surface (13b) that surrounds the half circumference are preferably provided. According to this, even when the annular thrust slide bearing cannot be disposed through the crankshaft, the half thrust thrust bearing is handled, and can be disposed at any position without any problem. In addition, for example, in the case of a vertically installed engine, oil for lubricating the journal of the crankshaft is provided by providing a protrusion having an inner wall surface that surrounds a half circumference opposite to the piston side of the bearing support portion. The oil drops from the journal bearing, but the oil is once received and collected by the inner wall surface of the protrusion, so the amount of lubricating oil in the thrust slide bearing can be increased easily. It is not necessary to provide an oil supply path and the like, and a sufficient oil for lubrication can be secured with a simple structure.

  As described above, according to the present invention, since the distance between the transmission rotating member and the thrust roller bearing is short, the length in bending vibration due to load input from the transmission rotating member is shortened, and bending vibration can be suppressed. Even if the axial load from the transmission side increases, the thrust load can be received by the thrust roller bearing, and the driving resistance of the crankshaft can be reduced more than in the case of the thrust slide bearing.

1 is a side cross-sectional view showing a crankshaft of an engine to which the present invention is applied and a peripheral portion thereof with a main part broken away. It is a principal part perspective view which shows the part which assembles a thrust slide bearing. It is principal part sectional drawing which shows the supply procedure of the lubricating oil to a thrust slide bearing.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a side sectional view showing a crankshaft 1 and its peripheral part of an automobile engine main body E to which the present invention is applied, with the main part cut away. In the present embodiment, the engine main body E is described as a series-type vertical installation, but is not limited to the series or vertical installation.

  In the illustrated example, three pistons 2 are connected to the crankshaft 1 via three connecting rods in the intermediate portion. A pulley 3 as a transmission rotating member is coaxially fixed to one end of the crankshaft 1 on the left side in the figure, and a transmission 4 is connected to the other end of the crankshaft 1 on the right side in the figure. Further, various auxiliary machines (not shown) such as a generator are integrally assembled with the engine body E, and a V belt 5 as an endless transmission member is wound around the pulley 3 and the various auxiliary machines. It has been.

  A part of a cylindrical cylinder wall that coaxially receives each piston 2 is extended in a suspended state toward the crankshaft 1 between both ends in the cylinder row direction of the engine body E and between the cylinders. A plurality of bearing support walls 6a, 6b, 6c and 6d are provided. Bearing caps 7a, 7b, 7c, and 7d are assembled to the lower ends of the bearing support walls 6a to 6d, respectively, and the journal of the crankshaft 1 is freely rotatable by the bearing support walls 6a to 6d and the corresponding bearing caps 7a to 7d. A bearing support portion for holding each journal slide bearing 8 to be supported by is constructed.

  The bearing structure for supporting the journal of the crankshaft 1 may be the same as that applied to a known engine. For example, the lower ends of the bearing support walls 6a to 6d are recessed in a semicircular shape surrounding the upper half of the journal of the crankshaft 1, and the bearing caps 7a to 7d surround the lower half of the journal of the crankshaft 1. A semicircular concave portion is provided, a circular hole is formed by both semicircular concave portions, and the slide bearing 8 is held in the hole. The slide bearings 8 do not necessarily have to be arranged coaxially with each other.

  The basic shape of the crankshaft 1 is the same as that of a known engine, and one end side bearing support wall 6a located closest to the pulley 3 among the plurality of bearing support walls 6a to 6d, and adjacent thereto. The shape of the portion between the adjacent bearing support walls 6b will be schematically described as a representative. The one end side bearing support wall 6a and the bearing cap 7a assembled thereto constitute an end bearing support portion, and the adjacent bearing support wall 6b and the bearing cap 7b assembled thereto constitute an adjacent bearing support portion. A pair of crank arms 1a and 1b extended between the one end side bearing support portions 6a and 7a and the adjacent bearing support portions 6b and 7b in a direction orthogonal to the axis of the crankshaft 1, and both crank arms A piston pin 1c provided between 1a and 1b is arranged.

  And between one end side bearing support part 6a * 7a located in the pulley 3 side most among the said several bearing support parts 6a * 7a-6d * 7d, and the step part 1d by which the diameter of the crankshaft 1 was expanded. A thrust roller bearing 9 is provided concentrically with the crankshaft 1. The thrust rolling bearing 9 may be a ball bearing or a roller bearing.

  In addition, the housing washer 9a of the thrust roller bearing 9 is fitted to the inner peripheral surface of the annular recessed portion 10 provided on the surface facing the crank arm 1a of the one end side bearing support portions 6a and 7a, and the shaft washer 9b. Is fitted to the outer peripheral surface of the stepped portion 1d of the crankshaft 1. In this way, the thrust roller bearing 9 is assembled between the one end side bearing support portions 6a and 7a and the crankshaft 1. It has been.

  Thereby, for example, when an axial load (arrow Fs in FIG. 1) from the transmission 3 is applied to the crankshaft 1 as a thrust load, the thrust load can be received by the thrust rolling bearing 9. As described above, the bearing that receives the thrust load is not a sliding bearing but a rolling bearing, so that a large bearing resistance does not occur even when a large thrust load is applied, and the crankshaft is driven more than in the case of a thrust sliding bearing. Reduction of resistance can be improved.

  The shaft end portion of the crankshaft 1 may have a large diameter on the transmission 4 side for large torque transmission, but may have a small diameter on the pulley 3 side. Accordingly, since the thrust roller bearing 9 is disposed on the pulley 3 side, the annular thrust roller bearing 9 is passed through the crankshaft 1 from the small diameter portion side, so that the thrust roller bearing 9 can be reduced in diameter. it can. In the case of passing through the large diameter portion on the transmission 4 side, the thrust bearing has been increased in diameter or divided into half types, but in the case of the half type, an annular thrust roller bearing 9 Therefore, the effect of reducing the driving resistance as in the present invention cannot be obtained.

  Further, since the thrust roller bearing 9 is provided at the one end side bearing support portions 6a and 7a closest to the pulley 3, a position serving as a fulcrum of bending vibration due to load input from the pulley 3 side is shown in FIG. Thus, the position P1 of the thrust rolling bearing 9 is reached, and the axial length L1 of the crankshaft 1 in bending vibration can be made as short as possible. On the other hand, when it is provided at the position P2 of the bearing support portions 6c and 7c close to the transmission 3, the length L2 in the same bending vibration becomes longer and the bending vibration becomes larger. On the other hand, since the thrust rolling bearing 9 is provided as close to the pulley 3 as possible, the suppression of bending vibration due to load input from the pulley 3 can be improved.

  A thrust slide bearing 11 having a shape of a semicircular ring concentric with the crankshaft 1 is provided on the surface of the adjacent bearing support wall 6b adjacent to the one end side bearing support portions 6a and 7a on the pulley 3 side. ing. As shown in FIG. 2, a semi-annular recessed portion 12 capable of holding the thrust slide bearing 11 in a substantially half-buried state in the thickness direction on the surface of the adjacent bearing support wall 6b on the pulley 3 side. The inner peripheral wall surface of the recessed portion 12 and the outer peripheral surface of the thrust slide bearing 11 are formed to have substantially the same diameter so that the thrust sliding bearing 11 fits into the recessed portion 12.

  With the thrust bearings 9 and 11 thus provided, the clearance between the surfaces receiving the thrust load with the crankshaft 1 can be reduced. The journal slide bearing 8 is provided with a gap necessary for smooth rotation of the crankshaft 1, whereas the thrust bearings 9 and 11 can be brought into sliding contact with the crankshaft 1 without a gap. The vibration of the crankshaft 1 in the radial direction can be suppressed at the locations of the bearings 9 and 11.

  Further, the thrust roller bearing 9 and the thrust slide bearing 11 can be regulated to both sides in the axial direction (thrust direction) of the crankshaft 1.

  On the other hand, a difference in material between the cylinder block (bearing support walls 6a to 6d) and the crankshaft 1 causes a difference in thermal expansion in the axial direction of the crankshaft 1 between the two members when the engine is hot. On the other hand, since the thrust slide bearing 11 is disposed at a position adjacent to the thrust roller bearing 9, that is, close to the thrust roller bearing 9, the distance between the thrust bearings 9 and 11 is one cylinder, and the distance between the surfaces that receive the thrust load. It is possible to improve the suppression of the increase amount of the clearance, and it is possible to regulate the displacement of the crankshaft 1 with respect to the axial direction during hot.

  In addition, a circle that is continuous with the concave portion 12 when viewed from the axial direction of the crankshaft 1 is formed on the end surface in the axial direction of the pulley 3 side of the bearing cap 7b that is assembled to the adjacent bearing support wall 6b that is an adjacent bearing support portion. A semi-annular ridge portion 13 is formed as a protruding portion. Both circumferential end faces 13 a of the semicircular ridge 13 are formed so as to be in contact with both circumferential end faces 9 a of the thrust slide bearing 11, and support both circumferential ends of the thrust slide bearing 11. In addition, the semicircular ridge 13 is formed with an inner wall surface 13b that encloses a half circumference of the crankshaft 1 opposite to the thrust slide bearing 11 side with a predetermined gap. As a result, a continuous annular ridge is formed by the thrust slide bearing 11 and the semi-annular ridge portion 13 in the assembled state of the thrust slide bearing 11. The height of the semi-annular ridge 13 (the height in the axial direction of the crankshaft 1) is set lower than the height of the thrust slide bearing 11 in the thickness direction.

  The lubricating oil supplied to the slide bearing 8 that supports the journal of the crankshaft 1 flows out to the outside of the adjacent bearing support wall 6b as shown by the arrows in FIG. 3, and is connected to the crankshaft 1 of the thrust slide bearing 11. Supplied to the sliding surface. Further, since the semi-annular ridge 13 is provided as described above, the lubricating oil flowing out to the bearing cap 7 b side is received by the inner wall surface 13 b of the semi-annular ridge 13. Thus, since the inner wall surface 13b of the semicircular ridge 13 functions as an oil reservoir, the amount of lubricating oil supplied to the thrust slide bearing 11 can be increased with a simple configuration.

  In the illustrated example, the protrusion is shown as an example of the semi-annular ridge 13, but the protrusion is an inner portion that surrounds the half circumference on the side opposite to the thrust slide bearing 11 side of the crankshaft 1. What is necessary is just to have the wall surface 13b, and the shape of the whole protrusion is not restricted to a semi-annular shape. For example, as shown by a two-dot chain line in FIG. 2, a plate-like thick portion 14 having a width substantially the same as the outer diameter of the thrust slide bearing 11 may be used. In this case, the plate-like thick portion 14 can be formed without any problem in die cutting when the bearing caps 7a to 7d are connected and formed integrally.

1 Crankshaft 2 Piston 3 Pulley (Rotating member for transmission)
4 Transmission 5 V-belt (endless transmission member)
6a to 6d Bearing support walls 7a to 7d Bearing caps 6a and 7a One end side bearing support portions 6b and 7b Adjacent bearing support portions 8 Journal slide bearing (bearing)
9 Thrust rolling bearing 11 Thrust sliding bearing 13 Semi-annular ridge 13a Circumferential end face 13b Inner wall 14 Plate-like thick part E Engine body

Claims (2)

The shaft is rotatably supported by a plurality of bearings disposed in the engine body, and has a transmission rotating member integrally wound around one end in the axial direction and the other end in the axial direction. A crankshaft thrust bearing structure having a crankshaft to which a transmission is coupled,
A plurality of bearing support portions that respectively support the plurality of bearings are provided on the engine body,
A thrust load of the crankshaft is applied between one end side bearing support portion of the plurality of bearing support portions closest to the transmission rotating member and a surface of the crankshaft facing the one end side bearing support portion. A thrust rolling bearing is provided to receive ,
A thrust slide for receiving a thrust load of the crankshaft between an adjacent bearing support portion adjacent to the one end side bearing support portion of the plurality of bearing support portions and a surface of the crankshaft facing the adjacent bearing support portion. thrust bearing structure of the crankshaft, characterized in that the bearing is provided. The thrust slide bearing is provided in a semi-annular shape on the piston side with respect to the crankshaft,
The adjacent bearing support part has a circumferential end on both sides opposite to the piston side of the thrust slide bearing that supports both ends in the circumferential direction of the thrust slide bearing, and a half circumference of the crankshaft on the side opposite to the thrust slide bearing The thrust bearing structure for a crankshaft according to claim 1, wherein a protrusion having an inner wall surface surrounding the portion is provided.

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