JPH07253009A - Cam driving member lubricating device of four-cycle internal combustion engine - Google Patents

Abstract

PURPOSE:To enable a cam shaft integrated with a valve system cam for opening and closing an intake/exhaust valve of a four-cycle internal combustion engine to be driven. CONSTITUTION:Chain chambers 22, 24 and 25 are respectively formed on a left crank case 4, a cylinder block 6, and a cylinder head 7, and a chain lensioner 31 and a chain guide 35 are respectively arranged on the upper and lower parts of the chain chambers 22, 24 and 25, and a guide rib 39 and an inclined part 40 are formed on a partition cover capable of being freely fitted/ removed to/from a circular opening 37 formed on the left crank case 4, and a connecting hole 23a is provided approximately above the guide rib 39 and the inclined part.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lubricating device for a driving member for driving a cam shaft integrated with a valve operating cam for opening and closing intake and exhaust valves of a four-cycle internal combustion engine.

[0002]

2. Description of the Related Art In a conventional four-cycle internal combustion engine, in order to rotationally drive a camshaft integrated with a valve cam that opens and closes intake and exhaust valves, a sprocket is integrally fitted to each of a crankshaft and a camshaft, and endless. In order to cope with elongation due to wear of the chain and change due to thermal expansion, the endless chain is bridged over these sprockets with slack, and a chain tensioner for stretching the endless chain is provided on the slack side of the endless chain. At the same time, a chain guide is provided on the tension side of the endless chain.

[0003]

Even in such a chain drive type valve operating device, depending on the operating condition of the internal combustion engine,
The endless chain may come off from the sprocket, and in order to prevent this, it was necessary to provide a chain drop prevention member.

However, if the chain drop-off prevention member is provided adjacent to the sprocket in a small chain chamber, the chain drop-off prevention member becomes an obstacle when the endless chain is reattached, and the chain replacement work is difficult to perform. Since it is necessary to remove the fall-off prevention member, the structure becomes complicated.

Further, it is necessary to sufficiently supply the endless chain and the sprocket with oil, but a generator or a dry belt transmission which must avoid the existence of oil is provided outside the chain drive sprocket integrated with the crankshaft. In the arranged internal combustion engine, it was difficult to configure the chain drop prevention member to be removed due to the presence of these generators and dry belt transmissions.

[0006]

SUMMARY OF THE INVENTION The present invention relates to an improvement of a camshaft drive member lubricating device for a four-cycle internal combustion engine which overcomes the above problems, and a crank rotatably supported by a crankcase. A cam shaft drive member and a power take-off member are arranged in parallel on the outer shaft of the shaft receiving portion, and the cam shaft drive member is placed in an oil wet atmosphere between the cam shaft drive member and the power take-out member. A partition portion that liquid-tightly partitions is interposed, and a guide rib is projectingly provided on an inner wall of the cam shaft driving member storage chamber that is partitioned by the partition portion so as to be adjacent to an outer circumference of the cam shaft driving member. Further, an oil discharge port that opens toward the guide ribs in the oil wet atmosphere is provided on the inner wall of the case that separates the crank chamber from the oil wet atmosphere.

Since the present invention is constructed as described above, the spaces surrounding the camshaft drive member and the power take-off member arranged on the crankshaft are partitioned in a liquid-tight manner by the partition section. As a result, it is possible to dispose a generator or a dry belt electric motor that surrounds the cam shaft driving member and is adjacent to a space that is set in an oil moist atmosphere and that avoids the presence of oil.

Further, in the present invention, a guide rib is provided on the partition member so as to be adjacent to the outer periphery of the cam shaft drive member, and an oil discharge port which is opened from the crank chamber toward the guide rib in the oil moist atmosphere is formed. Since it is provided on the inner wall of the case that separates the crank chamber and the oil-wet atmosphere, the oil scraped up by the operation of the internal combustion engine in the crank chamber is discharged from the oil discharge port of the inner wall of the case in the oil-wet atmosphere. The camshaft drive member adjacent to the guide rib can be lubricated by discharging the camshaft drive member toward the guide rib.

Further, according to the present invention, as described in claim 2, since the partition portion is composed of a partition lid which is detachably attached to the internal combustion engine body, maintenance and inspection work of the camshaft drive member is facilitated. Can be carried out.

Furthermore, in the present invention, as described in claim 3, the guide ribs are positioned laterally of the cam shaft drive member, and the upper portions of the guide ribs are inclined in a direction away from the cam shaft drive member. Since the oil discharge port provided on the inner wall of the case is arranged above the guide rib, the oil discharged from the oil discharge port can be reliably guided between the guide rib and the cam shaft drive member. Therefore, the cam shaft drive member can be sufficiently lubricated.

Further, in the present invention, when the camshaft driving member is composed of a driving sprocket and an endless chain wound around the driving sprocket, the partition lid is removed. As a result, the endless chain can be easily replaced, and maintenance and inspection work can be performed more efficiently and easily.

Further, by constructing the present invention as set forth in claim 5, the guide ribs can be integrated with the partition portion to simplify the structure and reduce the cost.

[0013]

EXAMPLE An example of the present invention shown in the drawings will be described below. A swing power unit 1 mounted on a scooter type motorcycle (not shown) includes an air-cooled 4-cycle internal combustion engine 2 in which a cylinder block 6 and a cylinder head 7 are oriented slightly upward from the front, and the air-cooled 4
A dry-type V that is directed rearward from the left side of the cycle internal combustion engine 2
The belt type continuously variable transmission 3 is integrated with each other.

The swing power unit 1 also includes a left crankcase 4 which also serves as a left crankcase of the air-cooled 4-cycle internal combustion engine 2 and a transmission case of the V-belt type continuously variable transmission 3, and an air-cooled 4-cycle internal combustion engine 2. Of the right crankcase 5, a cylinder block 6 integrally connected to the left crankcase 4 and the right crankcase 5, and a cylinder head 7 connected to the top end of the cylinder block 6.
It is divided into a transmission cover 8 which is detachably mounted on the left side of the left crankcase 4 and a right cover 9 which is connected to the right side of the right crankcase 5.

Further, a crank pin 12 of a crank shaft 11 which is rotatably supported by a left crank case 4 and a right crank case 5 via a bearing 10 is connected to a crank pin 12 of a crank shaft 11 via a needle bearing 13 at a large end of a connecting rod 14. The portion 15 is rotatably fitted, the small end 16 of the connecting rod 14 is connected to the piston 17 via the piston pin 18, and when the piston 17 reciprocates in the cylinder hole 19,
The crankshaft 11 is driven to rotate.

Furthermore, a chain chamber 22 is partitioned by a partition wall 21 supporting the bearing 10 on the left side of the crank chamber 20 surrounded by the left crank case 4 and the right crank case 5, and the chain chamber 22 communicates with each other. It is connected to the crank chamber 20 through a hole 23.

In addition, in the cylinder block 6 and the cylinder head 7, chain chambers 24 and 25 are formed from the chain chamber 22 along the center of the cylinder hole 19, and the drive sprocket 26 is attached to the crankshaft 11 in the chain chamber 22. Fitted together,
A cam shaft 28 integrally formed with a cam 27 for opening and closing an intake / exhaust valve (not shown) is rotatably supported by the cylinder head 7, and the left end of the cam shaft 28 has a number of teeth twice that of the drive sprocket 26. A driven sprocket 29 having a number of teeth is integrally fitted to the driven sprocket 26 and the driven sprocket.
An endless chain 30 is bridged over 29, and when the crankshaft 11 rotates, the cam 27 and the camshaft 28 are driven to rotate at half the rotation speed of the crankshaft 11.

A chain tensioner 31 is disposed above the chain chambers 22, 24 and 25, and the base of the chain tensioner 31 is pivotally supported by a supporting piece 32 of the left crankcase 4 so as to be vertically swingable. A tension adjusting device 33 is disposed on the cylinder block 6 above the intermediate portion of the chain tensioner 31, and the plunger of the tension adjusting device 33 is driven by the spring force of a coil spring (not shown) in the tension adjusting device 33. 34 is pushed downward, the chain tensioner 31 is swung downward around the support piece 32, and the required tension is applied to the endless chain 30.

Further, a chain guide 35 is arranged below the chain chambers 22, 24 and 25 so that the endless chain 30 can be stably fed into the chain chambers 22, 24 and 25. .

Furthermore, the left crankcase 4 is formed with a large-diameter circular opening 37 which is in communication with the transmission space 36 in the transmission cover 8 and is concentric with the crankshaft 11. A bolt (not shown) is screwed into the female screw portion 41 of the left crankcase 4 through the partition lid 38 that can be fitted to
An oil seal 42 is interposed between the partition lid 38 and the crankshaft 11.

On the right side surface of the partition lid 38, an arc-shaped guide rib 39 is formed behind the drive sprocket 26 and along the outer periphery of the drive sprocket 26, and an upper portion of the guide rib 39 is directed rearward and upward. Inclined part 40
Are formed.

In FIG. 1, the oil in the crank chamber 20 scraped up by the crank weight 45 which is integral with the crankshaft 11 rotating counterclockwise is used as the four communication holes 23.
It is possible to discharge from one of the communication holes 23a along the counterclockwise pitch circle 44 of the drive gear 43 of the kick starter.

Since the illustrated embodiment is constructed as described above, when the air-cooled four-cycle internal combustion engine 2 is put into operation, the crankshaft 11 rotates counterclockwise in FIG. The oil scraped up in the crank chamber 20 by the crank weight 45 integrated with is discharged into the chain chamber 22 from the communication hole 23a along the counterclockwise direction of the drive gear 43, and the inclined portion 40 guides the guide rib 39 and the drive sprocket. 26, and the drive sprocket 26 and the endless chain 30 are lubricated.

Further, since the partition chamber 38 and the oil seal 42 liquid-tightly shut off the chain chamber 22 in the oil moist atmosphere and the speed change space 36, the speed change space 36 is kept in the oil non-moist atmosphere. The dry V-belt type continuously variable transmission 3 that avoids the presence of oil can operate smoothly.

Further, since the partition lid 38 is removably attached to the circular opening 37 and the guide rib 39 and the inclined portion 40 are integrally formed in the circular opening 37, the circular opening 37 can be removed even when the endless chain 30 is replaced. Thus, the endless chain 30 can be easily replaced, and maintenance and inspection can be efficiently performed.

In the illustrated embodiment, the cam shaft drive member is a sprocket, but it may be a drive gear, or a driven gear integral with the cam shaft and the drive gear may be connected by a gear train.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional side view taken along the line I-I of FIG. 2 illustrating an embodiment of a camshaft drive member lubricating device for a 4-cycle internal combustion engine according to the present invention.

FIG. 2 is a vertical plan view cut along the line II-II of FIG.

[Explanation of symbols]

1 ... Swing power unit, 2 ... Air-cooled 4-cycle internal combustion engine, 3 ... V-belt type continuously variable transmission, 4 ... Left crankcase, 5 ... Right crankcase, 6 ... Cylinder block,
7 ... Cylinder head, 8 ... Transmission cover, 9 ... Right cover, 10 ... Bearing, 11 ... Crank shaft, 12 ... Crank pin, 13 ... Needle bearing, 14 ... Connecting rod, 15 ... Large end, 16 ... Small end Part, 17 ... Piston, 18 ... Piston pin, 19 ... Cylinder hole, 20 ... Crank chamber, 21 ... Partition wall, 22 ... Chain chamber, 23 ... Communication hole, 24, 25 ... Chain chamber, 26
... Drive sprocket, 27 ... Cam, 28 ... Cam shaft, 29 ... Followed sprocket, 30 ... Endless chain, 31 ... Chain tensioner, 32 ... Support piece, 33 ... Tension adjusting device, 34 ... Plunger, 35 ... Chain guide, 36 … Gear change space, 37… Circular opening,
38 ... Partition lid, 39 ... Guide rib, 40 ... Inclined part, 41 ... Female thread part, 42 ... Oil seal, 43 ... Drive gear, 44 ... Pitch circle, 45 ... Crank weight.

Claims (5)

[Claims] 1. A camshaft drive member and a power take-off member are arranged in parallel on a crankshaft bearing receiving outer shaft rotatably supported by a crankcase, and the camshaft drive member and the power take-out member. And a partition portion for liquid-tightly partitioning the cam shaft driving member in an oil-moist atmosphere, and the cam shaft driving member accommodating chamber is partitioned by the partition portion. A guide rib is provided so as to be adjacent to the outer periphery of the drive member, and an oil discharge port that opens from the crank chamber toward the guide rib in the oil-wet atmosphere is provided on the inner wall of the case that separates the crank chamber from the oil-wet atmosphere. A cam drive member lubricating device for a four-cycle internal combustion engine, characterized in that 2. The camshaft drive member lubricating device for a four-cycle internal combustion engine according to claim 1, wherein the partition portion is a partition lid detachably attached to the body of the internal combustion engine. 3. The guide rib is located radially outward of the cam shaft drive member, and an upper portion of the guide rib is inclined in a direction away from the cam shaft drive member, and an oil discharger provided on an inner wall of the case is provided. The cam drive member lubricating device for a four-cycle internal combustion engine according to claim 1, wherein the outlet is arranged above the guide rib. 4. The cam drive member for a four-cycle internal combustion engine according to claim 1, wherein the cam shaft drive member includes a drive sprocket, the drive sprocket, and an endless chain wound around the drive sprocket. Lubrication device. 5. The cam drive member lubricating device for a four-cycle internal combustion engine according to claim 1, wherein the guide rib is provided so as to project from the partition portion.