JPH0979019A - Oil supply hole structure of camshaft for multi-cylinder engine - Google Patents

Abstract

(57) [Summary] [PROBLEMS] When oil is supplied from the inner side of a cam shaft to the joint surface of the bearing of the cam shaft, the amount of this oil supplied is greater in the circumferential direction of the joint surface. To be even,
Ensure sufficient lubrication at the joint between the camshaft and the bearing. SOLUTION: Cam shafts 13 and 14 are supported on a cylinder head 7 by bearings 17 and 21, respectively. The bearings 17, 21
In the joint surface 34 with the cam shafts 13 and 14, the width of the lower surface 35 in the axial direction of the bearings 17 and 21 is made narrower than the width of the upper surface 36. The cam shafts 13 and 14
A first oil supply hole 61 is formed on the shaft centers 18 and 22 of the above, and the cam shafts 13 and 14 of the same are directed from the first oil supply hole 61 radially outward of the cam shafts 13 and 14 and to the bearings. 17,2
A plurality of second oil supply holes 62 extending toward 1 are formed.
The second oil supply holes 62 are displaced in the respective cylinders 2 in the circumferential direction of the cam shafts 13 and 14.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve operating mechanism for a multi-cylinder engine, and more particularly to a structure of an oil supply hole formed in a cam shaft for supplying oil to a bearing for supporting a cam shaft. It is a thing.

[0002]

2. Description of the Related Art A multi-cylinder engine is usually provided with a cylinder block having a plurality of cylinder holes whose axes are parallel to each other, and a cylinder head is attached to an upper end of the cylinder block with the axis vertically viewed. .

Conventionally, there is a valve operating mechanism of the above-mentioned engine which is constructed as follows.

That is, there is provided a cam shaft extending in a direction in which the cylinder holes are juxtaposed in a plan view, and the cam shaft is rotatably supported by a bearing on the cylinder head about its axis, and for each cylinder. A plurality of lifters juxtaposed in parallel with each other are slidably supported by the cylinder head and cam-engaged with the cam shaft, and the bearing is disposed between the juxtaposed lifters.

Then, the cam shaft is rotated in conjunction with the crank shaft of the engine, and the intake and exhaust valves are opened / closed in conjunction with the sliding of the lifters cam-engaged with the cam shaft. , The engine can be driven.

A lubricating device for supplying lubricating oil to the bearing is also provided.

The lubricating device includes a first oil supply hole formed on the cam shaft on the axis thereof and supplied with oil from the oil tank side, and a cam formed from the first oil supply hole formed on the cam shaft from the first oil supply hole. And a plurality of second oil supply holes extending radially outward of the shaft and toward the bearing.

[0008]

By the way, the bearing in the above-mentioned conventional structure is arranged between the lifters arranged in parallel for each cylinder, and these lifters are closely arranged close to each other. Therefore, the width of the lower surface of the bearing in the axial direction of the same bearing among the joint surfaces of the cam shaft and the journal is affected by the dense arrangement of the lifters and is larger than the width of the upper surface. It is narrow, that is, the area is small.

Therefore, it becomes difficult to retain oil at the joint portion between the journal and the lower surface of the bearing, and therefore, as the camshaft rotates, the downstream ends of the respective second oil supply holes move. When located on the lower surface of the bearing, a large amount of oil is momentarily supplied to the lower surface from the first oil supply holes through the second oil supply holes, and as a result, the first oil supply is performed. Although the oil is continuously supplied to the holes from the oil tank side, the pressure of the oil in the first and second oil supply holes sharply drops. Then, immediately after this, when the downstream end of each second oil supply hole reaches the upper surface due to the rotation of the cam shaft, the oil supply to the upper surface tends to be insufficient.

That is, in the above-mentioned conventional structure, the amount of oil supplied to the joint surface of the bearing through the first and second oil supply holes becomes non-uniform in the circumferential direction of the joint surface, so that the camshaft and the bearing are There is a possibility that the lubrication of the joint with will become insufficient.

The present invention has been made in view of the above circumstances, and when oil is supplied from the inner side of the cam shaft to the joint surface of the bearing of the cam shaft, the oil It is an object to make the supply amount more uniform in the circumferential direction of the joint surface so that the joint portion between the cam shaft and the bearing is sufficiently lubricated.

Another object of the present invention is to provide the above-mentioned lubrication with a simple structure.

[0013]

To achieve the above object, the oil supply hole structure for a camshaft for a multi-cylinder engine of the present invention is
It is as follows.

According to the first aspect of the present invention, the cam shafts 13 and 14 are attached to the cylinder head 7 by the bearings 17 and 21, and the axial center 18,
Of the joint surfaces 34 of the bearings 17 and 21 with the cam shafts 13 and 14, the width of a lower surface 35 in the axial direction of the bearings 17 and 21 is the same as that of the upper surface 36. Narrower than the width, while the camshafts 13 and 1 are
A first oil supply hole 61 to which the oil 44 is supplied from the oil tank 50 side is formed on the shaft centers 18 and 22 of the No. 4, and the cam shafts 13 and 14 are connected to the cam shafts from the first oil supply hole 61. 1
The bearings 17 and 21 facing radially outward of
In a valve operating mechanism of a multi-cylinder engine having a plurality of second oil supply holes 62 extending toward each other, the second oil supply holes 62 are arranged in the circumferential direction of the camshafts 13 and 14 for each cylinder 2 in the circumferential direction. It has been made to rank.

According to the invention of claim 2, in addition to the invention of claim 1, a plurality of lifters 30 arranged in parallel for each cylinder 2 are slidably supported on the cylinder head 7, respectively, and camshafts 13, 14 are provided. And the bearings 17 and 21 are arranged between the lifters 30 arranged side by side.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

In FIGS. 1 and 2, reference numeral 1 indicates an engine which is an internal combustion engine, and an arrow Fr indicates a front side when the engine 1 is mounted on an automobile.

The engine 1 includes a plurality of first to fourth cylinders 2
Is a 4-cycle parallel multi-cylinder engine having a. The engine 1 has a cylinder block 3, and the cylinder block 3 is provided so as to project from a crankcase, and a crankshaft having a horizontal axis is rotatably supported on the crankcase. A cylinder hole 4 is formed in each cylinder 2 in the cylinder block 3, and axes 5 of the cylinder holes 4 are parallel to each other.

As shown in the drawings, when the shaft centers 5 of the cylinder holes 4 are viewed vertically, the shaft centers 5 are arranged in parallel along the crankshaft in the horizontal direction, and the cylinder block 3
A cylinder head 7 is detachably attached to the upper end of the cylinder by a fastener 8, and the upper end of each of the cylinder holes 4 is closed by the cylinder head 7.

Pistons are fitted in the respective cylinder holes 4 so as to be slidable in the axial direction, and these pistons are interlockingly connected to the crankshaft by connecting rods.

A cylinder head 7 is provided in each cylinder hole 4 described above.
A space surrounded by the piston is a combustion chamber 9, and three intake valves and two exhaust valves that open and close the combustion chamber 9 to the outside are provided. An ignition plug 10 facing the discharge part is attached to the cylinder head 7.

A valve mechanism 12 for opening and closing the intake and exhaust valves is provided. The valve mechanism 12 includes an intake cam shaft 13 and an exhaust cam shaft 14, which are cam shafts extending in a direction (front-rear direction) in which the cylinder holes 4 are arranged side by side in a plan view.

Each end of the intake camshaft 13 is supported by the first bearing 16 with respect to the cylinder head 7, and a plurality of intermediate portions in the axial direction (two) are provided for each cylinder 2.
Is supported by the second bearing 17, which allows the intake camshaft 13 to be rotatably supported around its axis 18.

The exhaust cam shaft 14 is supported by the third bearing 20 at each end of the cylinder head 7, and the axial middle part is supported by the fourth bearing 21 for each cylinder 2. As a result, the exhaust cam shaft 14 is rotatably supported around the shaft center 22 thereof.

Each of the bearings 16, 17, 20, 21 has a bearing main body 25 for supporting the journal 24 of the camshaft 13, 14 from its lower surface side, and a cap 26 for supporting the same journal 24 from its upper surface side. , This cap 26
Fastener 27 for detachably fastening the bearing to the bearing body 25
It is composed of

The cylinder head 7 has a plurality of (three) lifter holes 29 for each cylinder 2 corresponding to the intake valves.
And a lifter 30 is slidably fitted in each of the lifter holes 29 in the axial direction. Further, the same cylinder head 7 is provided with a plurality (two) of other lifter holes 31 for each cylinder 2 corresponding to the exhaust valves, and the lifter 3 is provided in each of the lifter holes 31.
2 (however, this lifter 32 is not shown in the drawing) is slidably fitted in its axial direction.

Each of the lifters 30 has the intake camshaft 13
And the other lifters 32 are respectively cam-engaged with the exhaust cam shaft 14.
Further, in each of the cylinders 2, the second bearing 17 is arranged between the adjacent lifters 30, and in each of the cylinders 2,
The fourth bearing 21 is disposed between the other adjacent lifters 32.

In the above case, the lifters 30 and the other lifters 32 are closely arranged close to each other. Therefore, the second bearing 17 and the fourth bearing 21 are provided.
Of the joint surfaces 34 of the camshafts 13 and 14 with the journal 24, the lower surface 35 formed on the bearing body 25.
Is influenced by the dense arrangement of the lifters 30 and 32, so that the width in the direction along the axis 18 (axial direction) is narrower, that is, the area is smaller than that of the upper surface 36.
In FIG. 2, for convenience of explanation, the lower surface 35 is provided.
Are shown in a satin pattern.

The intake cam shaft 13 and the exhaust cam shaft 14 are interlocked with the crank shaft by interlocking means 38. The interlocking unit 38 includes a pulley 39 attached to one end of each shaft and a timing belt 40 wound around the pulley 39.

Then, the intake cam shaft 13 and the exhaust cam shaft 14 are rotated in conjunction with the crank shaft, and the slides of the lifters 30, 32 cam-engaged with the intake cam shaft 13 and the exhaust cam shaft 14. The intake / exhaust valves are appropriately opened / closed in conjunction with the movement, and the engine 1 is thereby driven.

In FIGS. 1, 3 and 4, a hydraulic variable valve timing device 42 is provided for varying the timing of rotation of the intake camshaft 13 with respect to the crankshaft.
The variable valve timing device 42 includes the intake camshaft 1
3, a variable body 43 interposed between one end of the variable body 3 and a pulley 39 attached thereto, and a control valve 45 that supplies pressurized oil 44 to the variable body 43.

The valve case 46 of the control valve 45 is integrally formed with the cap 26 of the first bearing 16 which supports one end of the intake camshaft 13, and a spool type valve body 47 is provided in the valve case 46. It is fitted so that it can slide axially.

A first oil passage 49 for communicating the outside of the valve case 46 with the valve body 47 is formed in the valve case 46.
The oil 44 in the oil tank 50, which is an oil pan formed on the (cap 26) and attached to the lower end of the crankcase at the upstream end of the first oil passage 49, is pressurized and supplied by the oil pump 51. It has become. An oil strainer is provided between the oil tank 50 and the oil pump 51, and an oil cooler and an oil filter are sequentially provided between the oil pump 51 and the first oil passage 49. .

An advance peripheral groove 52 and a retard peripheral groove 53 are formed on the outer peripheral surface of the journal 24 at one end of the intake camshaft 13 so as to be juxtaposed in the axial direction of the intake camshaft 13. Second and third oil passages 54 and 55 are formed in the valve case 46 (cap 26) for communicating the advance angle circumferential groove 52 and the retard angle circumferential groove 53 with the control valve 45. In addition, the intake camshaft 13 is provided with fourth and fifth oil passages 56 and 57 which communicate the advance angle circumferential groove 52 and the retard angle circumferential groove 53 with the variable body 43.
Is formed at one end of the.

The oil 44 supplied from the oil pump 51 to the first oil passage 49 by the operation of the control valve 45 is supplied to the valve body 47, the second oil passage 54, the advance circumferential groove 52, and the fourth oil passage 5.
If the variable body 43 is supplied through 6, the intake camshaft 13 is advanced with respect to the rotation of the crankshaft. On the contrary, the oil 44 supplied from the oil pump 51 to the first oil passage 49
Is supplied to the variable body 43 through the valve body 47, the third oil passage 55, the retarded circumferential groove 53, and the fifth oil passage 57, the intake camshaft 13 is retarded with respect to the rotation of the crankshaft.

In the above case, the advance circumferential groove 52 and the retard circumferential groove 53.
The oil 44 passing through lubricates the joint between the joint surface 34 of the first bearing 16 and the journal 24 of the intake camshaft 13 supported by the joint surface 34. In addition, the oil 44 flows from this joint portion to the interlocking means 38.
An oil seal 58 is provided between one end of the intake camshaft 13 and the first bearing 16 so as not to leak toward the side.

In all the figures, each of the bearings 16, 17, 2
A lubricating device 60 for supplying lubricating oil 44 to 0, 21 and the sliding contact portions of the lifters 30, 32 with respect to the inner peripheral surfaces of the lifter holes 29, 31 is provided.

The lubricating device 60 includes the intake camshaft 13
And a first oil supply hole 61 formed on the exhaust cam shaft 14 on the shaft centers 18 and 22, respectively, and an intake cam shaft 13 and an exhaust cam shaft 14 formed on the exhaust cam shaft 14, respectively. The camshaft 13 and the exhaust camshaft 14 are provided with a plurality of second oil supply holes 62 extending outward in the radial direction and toward the second and fourth bearings 17 and 21.

Lubricating circumferential grooves 64 are formed on the outer peripheral surface of the journal 24 at each one end of the intake cam shaft 13 and the exhaust cam shaft 14. In the intake camshaft 13, the lubricating circumferential groove 64 is formed in the advance circumferential groove 5 in the axial direction of the intake camshaft 13.
2 and the retard angle circumferential groove 53 are juxtaposed. Above intake camshaft 1
Third lubricating circumferential groove 64 and third oil passage 49 are connected to each other
An oil passage 65 is formed in the valve case 46 (cap 26).

A seventh oil passage 66 for communicating the respective lubricating circumferential grooves 64 of the intake camshaft 13 and the exhaust camshaft 14 with the respective first oil supply holes 61 is provided with the intake camshaft 13 and the exhaust camshaft 1.
No. 8 which is formed on each of the above-described intake camshafts 13 and exhaust camshafts 14 to connect the lubricating circumferential grooves 64 to each other.
An oil passage 67 is formed in the cylinder head 7. An oil seal 58 is also provided between one end of the exhaust cam shaft 14 and the third bearing 20 in the same manner as described above.

The oil 44 pressurized and supplied from the oil tank 50 to the first oil passage 49 by the oil pump 51 is supplied.
Is first supplied to the lubricating circumferential groove 64 of the intake camshaft 13 through the sixth oil passage 65, and the joint surface 34 of the first bearing 16 and the journal 24 of the intake camshaft 13 supported by the joint surface 34 are joined together. Lubricate parts.

The lubricating circumferential groove 64 of the intake camshaft 13 is also used.
The oil 44 supplied to the first oil supply hole 61 of the intake camshaft 13 is also supplied to the first oil supply hole 61 of the exhaust camshaft 14 through the eighth oil passage 67. Passes through the second oil supply holes 62 and joins the joining surfaces 34 of the second and fourth bearings 17 and 21 with the journals 24 and 24 of the intake camshaft 13 and the exhaust camshaft 14 supported by the joining surfaces 34. Lubricate parts.

In addition, the oil 44 leaked from the above-mentioned joints
Lubricates the sliding contact portions of the lifters 30, 32 with respect to the inner peripheral surfaces of the lifter holes 29, 31.

In FIGS. 6 and 7, the intake camshaft 13 is shown.
The second oil supply holes 62 in FIG. 2 are offset in the circumferential direction of the intake camshaft 13 for each cylinder 2, and this offset is directed from one end of the intake camshaft 13 to the other end. Accordingly, they are sequentially deviated by 90 ° in the circumferential direction. The configuration of the deviation of the second oil supply hole 62 is the same for the second oil supply hole 62 of the exhaust camshaft 14. In this case, the deviation angles may be 60 °.

According to the above construction, when the downstream end of the second oil supply hole 62 in a certain cylinder 2 is located at a part of the lower surface 35 of the joint surface 34 having a smaller area, the second oil supply hole is formed. A large amount of oil 44 is instantaneously supplied to the lower surface 35 through 62. However, at this time, since the downstream end of the second oil supply hole 62 in the other cylinder 2 is not located in a part of the lower surface 35, the bearings 17, 21 are not supplied from this second oil supply hole 62. A large amount of oil 44 is not supplied to the joining surface 34 of.

Therefore, it is possible to prevent the pressure of the oil 44 in the first and second oil supply holes 61 and 62 from suddenly dropping at a certain rotation angle while the cam shafts 13 and 14 make one rotation.

As a result, the oil 44 is supplied from the first oil supply hole 61 on the inner side of the cam shafts 13, 14 through the second oil supply hole 62 to the joint surface 34 of the second and fourth bearings 17, 21. In this case, the supply amount of the oil 44 is
Becomes more uniform in the circumferential direction.

In FIGS. 1, 3, and 5, the caps 26, 26 of the first bearing 16 and the second bearing 17 are integrated with each other, and they are reinforced with each other to improve the rigidity. The number of parts is reduced, and the structure of the valve mechanism 12 is simple.

As described above, each cap 26,
26 are integrated and reinforced so that
Even if the oil passage 49, the second oil passage 54, the third oil passage 55, and the sixth oil passage 65 are formed, sufficient strength and rigidity are ensured in each cap 26.

Since the two caps 26, 26 are integrated, the cam engaging portion between the intake camshaft 13 and the lifter 30 is covered by the connecting portion 69 of the caps 26, 26.
Therefore, the coupling portion 69 of the both caps 26, 26 with each other is provided.
Two openings 70, 70 for visual recognition are formed in the. Through the openings 70, 70, the degree of clearance of the cam engaging portion can be visually recognized, which is convenient for maintenance and inspection.

As described above with reference to the drawings, of the joint surfaces 34 of the second bearing 17 and the fourth bearing 21 with the respective journals 24 of the intake camshaft 13 and the exhaust camshaft 14, the second bearing 17 and the fourth bearing 4 are included. The width of the lower surface 35 in each axial direction of the bearing 21 becomes smaller than the width of the upper surface 36 because the second bearing 17 and the fourth bearing 21 are arranged between the lifters 30 and 32 arranged in parallel. In addition to this, a fastener 8 for fastening the cylinder head 7 to the cylinder block 3 is also provided.
Even if a notch is formed in a part of the bearing main body 25 to enable the above arrangement, the width of the lower surface 35 becomes narrow as described above.

The second oil supply hole 62 is formed by the intake camshaft 1
3, the exhaust cam shaft 14 may be penetrated in the radial direction. In addition, the second oil supply holes 62 in each cylinder 2,
62 may be offset from each other in the circumferential direction of the intake cam shaft 13 and the exhaust cam shaft 14.

[0053]

The effects of the present invention are as follows.

According to the first aspect of the invention, the cam shaft is rotatably supported by the cylinder head around the shaft center by the bearing, and the lower surface in the axial direction of the bearing is the same as the contact surface of the bearing with the cam shaft. The width of the side surface is narrower than the width of the upper surface, and on the other hand, a first oil supply hole for supplying oil from the oil tank side is formed on the axial center of the cam shaft, A valve operating mechanism of a multi-cylinder engine in which a plurality of second oil supply holes extending from the first oil supply hole toward the camshaft radial direction outward and toward the bearing are formed. Since each second oil supply hole is offset in the circumferential direction of the cam shaft, the following effects can be obtained.

That is, the lower surface of the joint surface of the bearing with the cam shaft has a smaller area than the upper surface thereof, and therefore, the joint portion between the cam shaft and the lower surface of the bearing is smaller. Therefore, it becomes difficult to retain oil. Therefore, when the downstream ends of the second oil supply holes are located on the lower surface of the bearing as the cam shaft rotates, the second oil supply holes are Through the first oil supply hole, a large amount of oil is instantaneously supplied to the lower surface, and as a result, the oil is continuously supplied to the first oil supply hole from the oil tank side. The oil pressure in the first and second oil supply holes tends to drop sharply.

However, in the present invention, as described above, each second oil supply hole for supplying oil from the first oil supply hole inside the camshaft toward the bearing is provided for each cylinder in the circumferential direction of the camshaft. Is biased at.

Therefore, when the downstream end of the second oil supply hole in a cylinder is located at a part of the lower surface of the joint surface having a small area, a large amount of oil is momentarily passed through the second oil supply hole. Are supplied to the lower surface. However, at this time, since the downstream end of the second oil supply hole in the other cylinder is not located in a part of the lower surface, a large amount of the second oil supply hole is applied to the joint surface of the bearing. No oil is supplied.

Therefore, it is possible to prevent the oil pressure in the first and second oil supply holes from dropping sharply at a certain rotation angle during one rotation of the cam shaft.

As a result, when the oil is supplied from the first oil supply hole on the inner side of the camshaft to the joint surface of the bearing through the second oil supply hole, the supply amount of this oil is equal to that of the joint surface. It becomes more uniform in the circumferential direction, so that the joint between the cam shaft and the bearing is sufficiently lubricated.

Moreover, since the desired lubrication as described above is achieved by simply displacing the second oil supply hole in the circumferential direction of the cam shaft, this lubrication can be obtained with a simple structure.

According to the invention of claim 2, in addition to the invention of claim 1, a plurality of lifters arranged in parallel for each cylinder are slidably supported by the cylinder head and are cam-engaged with the cam shaft. The bearing is arranged between the lifters arranged side by side.

That is, the bearing for supporting the cam shaft is arranged between the lifters arranged in parallel for each cylinder, and these lifters are closely arranged close to each other. For this reason, the lower surface of the joint surface of the bearing with the cam shaft is affected by the dense arrangement of the lifters, and has a smaller width, that is, a smaller area than the upper surface.

Therefore, even when the bearing is provided between the lifters, the joint portion between the cam shaft and the bearing is sufficiently lubricated, and this is achieved with a simple structure, as in the first aspect of the invention. To be done.

[Brief description of drawings]

FIG. 1 is a side sectional view of a valve mechanism.

FIG. 2 is a plan view of a cylinder head.

FIG. 3 is a plan view of what is shown in FIG.

FIG. 4 is a sectional view taken along the line 4-4 of FIG.

5 is a sectional view taken along line 5-5 in FIG. 3;

FIG. 6 is a side view of an intake camshaft.

7 is a sectional view taken along line 7-7 of FIG. 6;

[Explanation of symbols]

 1 Engine 2 Cylinder 3 Cylinder Block 4 Cylinder Hole 5 Shaft Center 7 Cylinder Head 12 Valve Mechanism 13 Intake Cam Shaft (Cam Shaft) 14 Exhaust Cam Shaft (Cam Shaft) 17 Second Bearing (Bearing) 18,22 Shaft Center 21 No. 21 4 bearing (bearing) 24 journal 30, 32 lifter 34 joining surface 35 lower surface 36 upper surface 44 oil 50 oil tank 51 oil pump 60 lubricator 61 first oil supply hole 62 second oil supply hole

Claims (2)

[Claims] 1. A cylinder block having a plurality of cylinder holes whose axes are parallel to each other is provided, the cylinder head is attached to the upper end of the cylinder block with the axes vertically, and the cylinder holes are aligned in a plan view. A cam shaft extending in the installed direction is provided, and the cam shaft is rotatably supported by the bearing on the cylinder head about its axis. The width of the lower surface of the cam is narrower than the width of the upper surface of the cam shaft, and a first oil supply hole for supplying oil from the oil tank side is formed on the axial center of the cam shaft. In a valve operating mechanism of a multi-cylinder engine, in which a plurality of second oil supply holes extending from the first oil supply hole to the camshaft radial direction outward and toward the bearing are formed in the shaft, Each above second Oil supply hole structure of a multi-cylinder engine camshaft that is deviation in the circumferential direction of the cam shaft supply hole. 2. A plurality of lifters arranged in parallel for each cylinder are slidably supported by a cylinder head and cam-engaged with a cam shaft, and a bearing is arranged between the juxtaposed lifters. The oil supply hole structure for a camshaft for a multi-cylinder engine according to Item 1.