JP7107020B2 - internal combustion engine - Google Patents

Description

The present invention relates to internal combustion engines.

In the internal combustion engine of Patent Document 1, a crankshaft is accommodated in a cylinder block. The crankshaft passes through the cylinder block, and the end of the crankshaft protrudes outside the cylinder block. A crank sprocket is fixed to the end of the crankshaft. A cylinder head is fixed to the upper end of the cylinder block. A pair of camshafts are accommodated in the cylinder head. Each camshaft is rotatably supported by a cylinder head and a cam cap fixed to the upper end of the cylinder head. The camshaft passes through the cylinder head, and the end of the camshaft protrudes outside the cylinder head. A cam sprocket is fixed to the end of each camshaft. A timing chain is wound around these crank sprockets and two cam sprockets.

Further, in the internal combustion engine of Patent Document 1, the cam cap is provided with three oil jets. The positions of the oil jets are determined so that the oil can be injected toward the starting point of meshing with the cam sprocket in the timing chain, the ending point of meshing with the cam sprocket, and an intermediate point between the two cam sprockets.

JP-A-2001-27109

In the internal combustion engine of Patent Document 1, the oil from the oil jet is directly injected to the timing chain. Therefore, the cam sprocket is indirectly supplied with the oil adhering to the timing chain. Therefore, depending on the configuration of the timing chain and cam sprockets, the oil may not reach the cam sprockets sufficiently.

In order to solve the above problems, the present invention provides a cylinder block in which cylinders for burning fuel are defined, a cylinder head fixed to the upper end of the cylinder block, and a cylinder fixed to the upper end of the cylinder head. and a cam cap rotatably supporting a pair of camshafts together with the cylinder head, wherein the crank sprocket is fixed to the crankshaft and the cam sprocket is fixed to each of the pair of camshafts. A timing chain for transmitting rotational torque is wound around, and at least one of the cylinder block, the cylinder head, and the cam cap is provided with an oil jet for supplying oil. The oil jet is open inside the range defined by the timing chain when viewed in plan from the axial direction of the crankshaft, and the opening of the oil jet is located between the two cam sprockets. Of these, the cam sprocket is oriented one before the crank sprocket in the running direction of the timing chain.

According to the above configuration, the oil from the oil jacket is directly injected to the cam sprocket one ahead of the crank sprocket in the running direction of the timing chain. Therefore, of the two cam sprockets, it is possible to make it easier for the oil to reach the cam sprocket, which wears relatively easily.

1 is a schematic side view of an internal combustion engine; FIG.

One embodiment of an internal combustion engine will be described with reference to FIG. In the following description, it is assumed that the internal combustion engine is mounted on a vehicle, and the vertical direction of the vehicle is the vertical direction of the internal combustion engine.

As shown in FIG. 1, the internal combustion engine E has a generally cubic cylinder block 10 . A plurality of cylinders (not shown) are partitioned inside the cylinder block 10, and fuel is combusted inside these cylinders. A plurality of crank caps (not shown) are fixed to the lower end of the cylinder block 10 . A crankshaft 50 is rotatably supported between the cylinder block 10 and the crank cap. The crankshaft 50 passes through the cylinder block 10 and both ends of the crankshaft 50 protrude outside the cylinder block 10 . A crank sprocket 51 is fixed to one end of the crankshaft 50 in the axial direction (the end on the front side of the paper in FIG. 1). In addition, in FIG. 1, the crank sprocket 51 is schematically illustrated by a circle.

A bottomed box-shaped oil pan 20 is arranged at the lower end of the cylinder block 10 so as to cover the crankshaft 50 . Inside the oil pan 20, oil for lubricating various parts of the internal combustion engine E is accommodated. Further, the oil pan 20 accommodates an oil pump (not shown) for pumping the oil accommodated in the oil pan 20 .

At the upper end of the cylinder block 10, a generally cubic cylinder head 30 having intake ports and exhaust ports is fixed. On the upper surface of the cylinder head 30, a first semicircular recess 31 and a second semicircular recess 32 are recessed in plan view in the axial direction of the crankshaft 50. As shown in FIG. When the width direction of the internal combustion engine E is defined as the direction perpendicular to both the vertical direction of the internal combustion engine E and the axial direction of the crankshaft 50 (horizontal direction in FIG. 1), the first semicircular recessed portion 31 The second semicircular concave portion 32 is positioned on the other widthwise side of the crankshaft 50 . A plurality of first semicircular recesses 31 and second semicircular recesses 32 are arranged side by side in the axial direction of the crankshaft 50 .

A cam cap 80 is fixed to the upper end of the cylinder head 30 . In the lower surface of the cam cap 80, a semicircular first shaft accommodating portion 81 and a second semicircular shaft accommodating portion 82 are recessed in plan view in the axial direction of the crankshaft 50. As shown in FIG. The cam cap 80 is arranged such that the first shaft accommodating portion 81 and the second shaft accommodating portion 82 face the first semi-circular recess 31 and the second semi-circular recess 32 of the cylinder head 30, respectively. A plurality of cam caps 80 are arranged side by side in the axial direction of the crankshaft 50 corresponding to the number of sets of the first semicircular recesses 31 and the second semicircular recesses 32 .

A substantially rod-shaped first camshaft 60 is inserted into a circular hole (bearing) formed by the first semicircular recess 31 and the first shaft accommodating portion 81 in plan view. The first camshaft 60 is rotatably supported by the first semicircular concave portion 31 and the first shaft accommodating portion 81 . A substantially bar-shaped second camshaft 70 is inserted into a circular hole (bearing) formed by the second semicircular recess 32 and the second shaft accommodating portion 82 in a plan view. The second camshaft 70 is rotatably supported by the second semicircular concave portion 32 and the second shaft accommodating portion 82 . Both the first camshaft 60 and the second camshaft 70 extend parallel to the central axis of the crankshaft 50 . One of the first camshaft 60 and the second camshaft 70 is for opening and closing the intake valves, and the other is for driving the exhaust valves.

Both ends of the first camshaft 60 and both ends of the second camshaft 70 protrude outside the cylinder head 30 . A first cam sprocket 61 is fixed to one end of the first camshaft 60 . A second cam sprocket 71 is fixed to one end of the second camshaft 70 . In addition, in FIG. 1, the first cam sprocket 61 and the second cam sprocket 71 are schematically indicated by circles.

A cylinder head cover 40 is fixed to the upper end of the cylinder head 30 . The cylinder head cover 40 covers most of the first camshaft 60, most of the second camshaft 70, and the plurality of cam caps 80 from above.

In the internal combustion engine E, a timing chain 90 is wound around the crank sprocket 51 , the first cam sprocket 61 and the second cam sprocket 71 . In this embodiment, the crank sprocket 51 rotates clockwise when viewed from the one axial side of the crankshaft 50 . Then, the timing chain 90 sent out from the crank sprocket 51 travels through the first cam sprocket 61 and the second cam sprocket 71 and returns to the crank sprocket 51 again.

A chain case 130 surrounding the timing chain 90 is attached to the outer surface of the cylinder block 10 on one side in the axial direction of the crankshaft 50 . The chain case 130 is composed of a first case 131 attached to the internal combustion engine E and a second case (not shown) having a shape similar to that of the first case 131 in a plan view. The first case 131 and the second case are arranged to face each other, and the end surface of the second case abuts against the end surface of the first case 131 on the side opposite to the internal combustion engine E. A chain chamber R for accommodating the timing chain 90 is defined between the first case 131 and the second case.

A first case 131 of the chain case 130 includes a plate-like main wall portion 132 and an outer edge wall portion 133 that extends from the edge of the main wall portion 132 toward one axial direction side of the crankshaft 50 . . The plan view shape of the main wall portion 132 is designed according to the trajectory of the timing chain 90 and the like. In this embodiment, it is elongated in the vertical direction as a whole, with the upper end reaching the cylinder head cover 40 and the lower end reaching the oil pan 20 . A surface of the main wall portion 132 on the other side in the axial direction of the crankshaft 50 is fixed to a surface of the cylinder block 10 on the one side in the axial direction of the crankshaft 50 . Further, the main wall portion 132 is provided with notches and holes for passing the crank sprocket 51, the first cam sprocket 61, and the second cam sprocket 71 therethrough.

A fixed guide portion 100 that guides the running of the timing chain 90 is fixed to the surface of the main wall portion 132 of the first case 131 on one side in the axial direction of the crankshaft 50 . The fixed guide portion 100 is positioned between the crank sprocket 51 and the second cam sprocket 71 . The fixed guide portion 100 has a long and slightly curved shape (arched shape), and the outside of the curve faces the center of the internal combustion engine E in the width direction. The timing chain 90 is in contact with the curved outer surface of the fixed guide portion 100 . The fixed guide portion 100 is fixed to the cylinder block 10 with bolts B at its longitudinal upper and lower sides.

A rocking guide portion 110 that guides travel of the timing chain 90 is fixed to a surface of the main wall portion 132 of the first case 131 on one side in the axial direction of the crankshaft 50 . The swing guide portion 110 is positioned between the crank sprocket 51 and the first cam sprocket 61 . The rocking guide portion 110 has an elongated curved shape (arched shape), and the outer side of the curve faces the center of the internal combustion engine E in the width direction. That is, the outside of the curve of the rocking guide portion 110 faces the outside of the curve of the fixed guide portion 100 . A pin P is inserted through the rocking guide portion 110 at its longitudinally lower side. The rocking guide portion 110 is attached to the cylinder block 10 so as to be rockable about the pin P. As shown in FIG. A timing chain 90 is in contact with the curved outer surface of the swing guide portion 110 .

A tensioner 120 is fixed to the main wall portion 132 of the chain case 130 to press the swing guide portion 110 to swing the swing guide portion 110 . The tensioner 120 is located on one side of the timing chain 90 that is wound between the crankshaft 50 and the first cam sprocket 61 in the width direction of the internal combustion engine E. As shown in FIG. A tip portion of the tensioner 120 abuts on the inside of the curve of the swing guide portion 110 .

In this embodiment, the swing guide portion 110 is rotated most toward the tensioner 120 (most counterclockwise in FIG. 1). The central portion in the extending direction is arranged to reach the other side in the width direction of the internal combustion engine E from the central axis of the crankshaft 50 .

As shown in FIG. 1, an oil jet 83 for supplying oil is opened to the outer surface of the cam cap 80 located on the one axial side of the crankshaft 50, among the plurality of cam caps 80, on the one axial side. ing. An opening 84 of the oil jet 83 is arranged between the first shaft housing portion 81 and the second shaft housing portion 82 in the cam cap 80 . The opening 84 is arranged closer to the second shaft accommodating portion 82 than the center between the first shaft accommodating portion 81 and the second shaft accommodating portion 82 in the cam cap 80 . An opening 84 of the oil jet 83 is positioned near the lower end of the cam cap 80 . Therefore, in the internal combustion engine E, the opening 84 of the oil jet 83 is arranged inside the range defined by the timing chain 90 when viewed from above in the axial direction of the crankshaft 50 .

Further, in the internal combustion engine E, a part of the opening 84 of the oil jet 83 is located within the range of the diameter of the second cam sprocket 71 when viewed from the axial direction of the crankshaft 50, and the other part is It is located outside the diameter range of the second cam sprocket 71 . Therefore, the oil injected from the opening 84 of the oil jet 83 is slightly biased toward the second cam sprocket 71 in the width direction of the internal combustion engine E.

Also, the opening 84 of the oil jet 83 is located above the crank sprocket 51 . In other words, the opening 84 of the oil jet 83 is positioned within the range of the diameter of the crank sprocket 51 in the width direction of the internal combustion engine E. Note that the size of the opening 84 in FIG. 1 is exaggerated.

The oil jet 83 communicates with an oil passage inside the cam cap 80 (not shown) that supplies oil to the first camshaft 60 and the second camshaft 70 . Therefore, part of the oil pressure-fed by the oil pump in the oil pan 20 is supplied to the oil jet 83 through the oil passage in the cam cap 80 and jetted from the opening 84 of the oil jet 83 .

The action and effect of this embodiment will be described.
(1) In this embodiment, as the crank sprocket 51 rotates clockwise, the timing chain 90 is sent out from the crank sprocket 51, passes through the first cam sprocket 61 and the second cam sprocket 71, and returns to the crank sprocket 51. returned. Here, since the timing chain 90 is pulled by the rotation of the crank sprocket 51 between the second cam sprocket 71 and the crank sprocket 51, the tension of the timing chain 90 increases. On the other hand, the timing chain 90 is sent out by the rotation of the crank sprocket 51 between the crank sprocket 51 and the first cam sprocket 61, so the tension of the timing chain 90 is reduced. Therefore, the tension of the timing chain 90 wound around the second cam sprocket 71 is greater than the tension of the timing chain 90 wound around the first cam sprocket 61 . Therefore, the friction between the second cam sprocket 71 and the timing chain 90 is greater than the friction between the first cam sprocket 61 and the timing chain 90 . That is, the second cam sprocket 71 wears more easily than the first cam sprocket 61 .

In this embodiment, the opening 84 of the oil jet 83 is directed toward the second cam sprocket 71 on the side of the timing chain 90 where the tension is large. The oil injected from the oil jet 83 is directly injected to the second cam sprocket 71 . This makes it easier for the oil to reach the second cam sprocket 71 . As a result, large friction between the second cam sprocket 71 and the timing chain 90 can be reduced, so that wear of the second cam sprocket 71 can be reduced.

(2) In the present embodiment, the opening 84 of the oil jet 83 is located between the first cam sprocket 61 and the second cam sprocket 71 in the internal combustion engine E when viewed in plan from the axial direction of the crankshaft 50. positioned. Therefore, the oil injected from the opening 84 of the oil jet 83 is directly injected not only to the second cam sprocket 71 but also to the first cam sprocket 61 . As a result, in addition to the second cam sprocket 71 , the oil can be easily delivered to the first cam sprocket 61 . As a result, the friction generated between the first cam sprocket 61 and the timing chain 90 can be reduced, so the wear of the first cam sprocket 61 can be reduced.

(3) In the present embodiment, the opening 84 of the oil jet 83 is positioned within the range of the diameter of the crank sprocket 51 in the width direction of the internal combustion engine E. Therefore, the oil injected from the opening 84 drops onto the crank sprocket 51 when dropped downward. As a result, oil can be supplied to the crank sprocket 51 in addition to the second cam sprocket 71 and the first cam sprocket 61 . As a result, friction occurring between the crank sprocket 51 and the timing chain 90 can be reduced, so wear of the crank sprocket 51 can be reduced.

(4) In the present embodiment, the central portion of the swing guide portion 110 in the extending direction extends to the other side of the internal combustion engine E in the width direction of the central axis of the crankshaft 50 . Therefore, when the oil injected from the opening 84 drips downward, it drips onto the swing guide portion 110 and the portion of the timing chain 90 that is in contact with the swing guide portion 110 . As a result, the sliding portion between the timing chain 90 and the swing guide portion 110 can be lubricated with oil. As a result, friction between the timing chain 90 and the swing guide portion 110 can be reduced, and wear of the swing guide portion 110 can be reduced.

The above embodiment can be implemented with the following modifications. This embodiment and the following modified examples can be implemented in combination with each other within a technically consistent range.
・If the opening 84 of the oil jet 83 is directed toward the second cam sprocket 71, it is positioned outside the range of the diameter of the second cam sprocket 71 when viewed from above in the axial direction of the crankshaft 50. good too. For example, if the central axis of the opening 84 is inclined with respect to the central axis of the crankshaft 50 and the second cam sprocket 71 is positioned on the central axis of the opening 84, the opening 84 is positioned at the second position. It can be said that the cam sprocket 71 is oriented. With such a configuration of the opening 84 , oil can be directly injected to the second cam sprocket 71 .

- The oil jet 83 may not be provided on the cam cap 80 . For example, it may be attached to the cylinder head 30 or the cylinder block 10 and communicate with the oil supply passage inside the cylinder head 30 or the cylinder block 10 . For example, even if the oil jet 83 is provided in the cylinder block 10 , oil can be directly injected to the second cam sprocket 71 if the opening 84 is directed toward the second cam sprocket 71 .

- There may be more than one oil jet 83 . For example, a plurality of oil jets 83 may be attached to the cam cap 80 . Also, a plurality of oil jets 83 may be separately attached to the cam cap 80 , the cylinder head 30 and the cylinder block 10 .

- Not the central portion of the swing guide portion 110 in the extending direction, but one of the ends in the extending direction may extend to the other side in the width direction of the internal combustion engine E from the central axis of the crankshaft 50 . In this case also, the oil dripped from the opening 84 of the oil jet 83 can lubricate the swing guide portion 110 and the timing chain 90 .

The central portion in the extending direction of the swing guide portion 110 does not have to reach the other side in the width direction of the internal combustion engine E with respect to the central axis of the crankshaft 50 . Further, only when the center portion of the rocking guide portion 110 in the extending direction is rotated most toward the fixed guide portion 100 side, the center portion of the rocking guide portion 110 in the extending direction is positioned further than the central axis of the crankshaft 50 . It may extend to the other side in the width direction of the internal combustion engine E.

The central portion of the fixed guide portion 100 in the extending direction may reach one side of the central axis of the crankshaft 50 in the width direction of the internal combustion engine E. In this case, when the oil jetted from the oil jet 83 drops downward, it drops onto the fixed guide portion 100 and the portion of the timing chain 90 that is in contact with the fixed guide portion 100 . As a result, the portion where the timing chain 90 and the fixed guide portion 100 slide can be lubricated with oil. As a result, friction between the timing chain 90 and the fixed guide portion 100 can be reduced, and wear of the fixed guide portion 100 can be reduced. In this case, it is necessary to avoid interference with the swing guide portion 110 .

- In the internal combustion engine E, other sprockets and pulleys not described in the above embodiments may be attached. For example, a sprocket attached to the input shaft of the oil pump may be attached.

- The configurations of the fixed guide portion 100, the swing guide portion 110, the tensioner 120, and the chain case 130 may be changed as appropriate. For example, when another sprocket and pulley not described in the above embodiment are attached, the chain case 130 may be configured to accommodate the other sprocket and pulley in the chain chamber R. Further, the position of the pin P that fixes the swing guide portion 110 may be on the upper side in the longitudinal direction. Furthermore, the position where the tensioner 120 abuts against the swing guide portion 110 may be on the lower side in the longitudinal direction.

- In the internal combustion engine E, the configurations of the cylinder block 10, the oil pan 20, the cylinder head 30, and the cylinder head cover 40 may be changed as appropriate. For example, these configurations can be modified to fit chain case 130 attachments and other sprockets and pulleys not described in the above embodiments. In addition, the configuration of the cylinder head 30 can be changed according to the number of cylinders in the cylinder block 10 .

DESCRIPTION OF SYMBOLS 10... Cylinder block 20... Oil pan 30... Cylinder head 31... First semicircular recess 32... Second semicircular recess 40... Cylinder head cover 50... Crankshaft 51... Crank sprocket 60... First Camshaft 61 First cam sprocket 70 Second camshaft 71 Second cam sprocket 80 Cam cap 81 First shaft accommodating portion 82 Second shaft accommodating portion 83 Oil jet 84... Opening, 90... Timing chain, 100... Fixed guide part, 110... Swing guide part, 120... Tensioner, 130... Chain case, 131... First case, 132... Main wall part, 133... Outer edge wall part, B... bolt, E... internal combustion engine, P... pin, R... chain chamber

Claims (1)

A cylinder block in which cylinders for burning fuel are defined, a cylinder head fixed to the upper end of the cylinder block, and a pair of camshafts fixed to the upper end of the cylinder head and rotatable together with the cylinder head. An internal combustion engine comprising: a cam cap supporting a
A timing chain for transmitting rotational torque is wound around a crank sprocket fixed to the crankshaft and a cam sprocket fixed to each of the pair of camshafts,
At least one of the cylinder block, the cylinder head, and the cam cap is provided with an oil jet for supplying oil,
The oil jet is open inside a range defined by the timing chain when viewed in plan from the axial direction of the crankshaft,
The opening of the oil jet is oriented to the cam sprocket that is one before the crank sprocket in the running direction of the timing chain, out of the two cam sprockets ,
A direction perpendicular to both the vertical direction and the axial direction of the crankshaft is defined as the width direction, and when viewed from above from the axial direction of the crankshaft, the opening extends in the width direction to the range of the diameter of the crank sprocket. is located within
When viewed from above in the axial direction of the crankshaft, part of the opening is located within a range of diameters of the cam sprocket immediately before the crank sprocket in the running direction of the timing chain. The other part of the part is located outside the diameter of the cam sprocket one before the crank sprocket in the running direction of the timing chain.
internal combustion engine.

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