JP2576593B2 - Cam Chien lubrication system for 4-cycle engine - Google Patents

Abstract

PURPOSE:To reduce an engine weight by providing an O-ring around through holes provided on a crank case, a cylinder head, and a cylinder block, and attaching the cover of a cam chain chamber of the outer side surface. CONSTITUTION:The shaft ends of shafts 14b, 29, 22 are respectively ejected on through holes 27, 30, 23 of a crank case 8, a cylinder block 9, and a cylinder head 10. Further, O-rings 38, 39, 37 are respectively provided around the holes 27, 30, 23, so that the base cover 40 of a cam chain chamber 42 is attached on the outer side surface. Thereby, the width of the cam chain chamber is reduced so as to reduce an engine weight.

Description

The present invention relates to a cam chain lubrication system for a four-stroke engine having an overhead cam.

(Prior Art) Overhead cam type four-stroke engines often use a cam chain to drive the camshaft in conjunction with the crankshaft, and the cam chain is a cam chain formed in a cylinder block and a cylinder head. It is common to run indoors.

However, in such a case where the cam chain is provided inside, the assemblability is not good, the engine width is increased, and the weight is increased. For lubrication of the cam chain, the lubrication of the valve mechanism of the cylinder head is followed by the use of oil that falls down the cam chain and returns to the oil pan, which tends to cause excessive lubrication and increase the mechanical loss. There is a problem that the oil temperature rises due to the sliding of.

On the other hand, it is conceivable that the engine weight can be reduced and a unique lubrication mechanism can be adopted by arranging the cam chain chamber outside the cylinder block or cylinder head. However, because of the wide range of the crankcase, the cylinder block, and the cylinder head, there is a new problem that it is difficult to secure the machining accuracy of the mounting surface.

(Problems to be Solved by the Invention) When the cam chain is disposed outside the crankcase, the cylinder block, etc., the engine is reduced in weight and lubrication of the cam chain is advantageous, but processing accuracy in assembling is secured. In view of this problem, the present invention provides a rough rough machining accuracy for the crankcase, the cylinder block, and the outer surface of the cylinder head so that a separate cam chain chamber can be easily mounted, and is suitable for cam chain lubrication. It is an object of the present invention to provide a cam cycle lubrication device for a four-stroke engine, which is capable of supplying oil of the type described above.

[Configuration of the invention]

(Means for Solving the Problems) In order to achieve the above object, a cam chain lubricating apparatus for a four-stroke engine according to the present invention includes a cam drive sprocket fixed to a crankshaft to transmit rotation from the crankshaft to an overhead camshaft. A four-cycle engine in which a cam chain is mounted on a gear, a cam driven sprocket gear fixed to a cam shaft or a cam drive gear shaft that links the cam shaft, and an idle sprocket gear on an idle shaft provided as necessary. In the above, the shaft ends of the crankshaft, camshaft or cam drive gear shaft, and idle shaft are projected outward from through holes provided in the crankcase, the cylinder head, and the cylinder block, and the outer surface surrounds each through hole. Form the surrounding O-ring groove, insert the O-ring, and pass each shaft end Attach the base cover of the perforated Cam Chien chamber to this outer surface,
In this base cover, a cam drive sprocket gear, a cam driven sprocket gear, and an idle sprocket gear are fixed to each shaft end, and an outer cover is connected to the base cover to form an independent cam chain chamber.
In this configuration, a part of the lubricating oil for the bearing of the crankshaft is supplied to the cam drive sprocket gear via the crankshaft end.

(Operation) With this configuration, the separate cam chain chamber can be hermetically mounted on the outer surface of the crankcase or cylinder block simply by pressing the O-ring around the protruding end of the crankshaft, camshaft, or the like. Weight can be reduced. No special shaft sealing device is required to protrude from the shaft, and the mounting surface of the crankcase or the like can have relatively rough machining accuracy.

The crank chamber and the cam chain can communicate with each other through the through hole in the crankcase and the hole in the cam chain base cover, and the minimum necessary lubricating oil is supplied to the cam drive sprocket gear through the crankshaft end. In addition, it is possible to prevent a mechanical loss and an increase in the oil temperature of the oil in the oil pan.

(Embodiment) A description will be given below with reference to the drawings showing an embodiment of the present invention.

1 is a longitudinal rear view of a four-stroke engine equipped with the cam chain lubrication device of the present invention, FIG. 2 is a side view, FIG. 3 is a plan view, and FIG. 4 is a side view of a motorcycle equipped with this engine. FIG.

As shown in FIG. 4, the engine unit 1 forms the core of the frame, and the front wheel 4 is supported by a steering head 3 at the front end of a box type frame 2 connected to the upper part, and a swing arm 5 pivotally supported at the rear end. The engine part on which the rear wheel 6 is supported is a square type 4 in which four cylinders 7 are arranged in front and rear and left and right, and two crankshafts 14a and 14
The crankcase 8, the cylinder block 9, the cylinder head 10, and the head cover 11 are sequentially stacked.

Each cylinder 7 is a four-stroke engine in which a top field type ventilation passage 12 is introduced from above, and an exhaust passage 13 is led outward, and the two front and rear crankshafts 14a,
Continued by 14b.

The camshaft 19 on which the intake and exhaust cams 17 and 18 for controlling the opening and closing of the intake valve 15 and the exhaust valve 16 of each cylinder 7 are common to the left and right, and four camshafts are arranged in front and rear. A cam driven gear 20 is formed at the center of the cam shaft 19, and each adjacent cam driven gear 20 is connected to a cam drive gear 21 and an idle gear 21.
is engaged with a. The rotation of the cam drive gear 21 drives each cam shaft 19 at one time.

The outer end of the cam drive gear shaft 2 having the cam drive gear 21 fixed to the inner end thereof projects through the through hole 23 to the side surface of the cylinder head 10 so that the cam driven sprocket gear 24 is fixed. . A bearing 25 is fitted in the through hole 23.

A cam drive sprocket gear 26 is formed at one end of the front and rear rear crankshafts 14b, and protrudes outward from a through hole 27 provided in the crankcase 8. Part of the through hole 27 is a bearing 28
Is fitted.

Further, an idle shaft 29 is pivotally supported on a part of the cylinder block 9, and an outer end of the idle shaft 29 protrudes from the through hole 30 to an outer surface, so that an idle through rocket gear 31 is fixed. A bearing 32 is fitted in the through hole 30. This idle shaft 29
Drives the impeller shaft 36 of the water pump 35 via the reduction gears 33 and 34.

The outer surface of the cylinder head 10 around the through hole 23, the through hole 27
O-ring grooves surrounding the through holes 23, 27, 30 are formed on the outer surface of the surrounding crankcase 8 and the outer surface of the cylinder block 9 around the through holes 30, and O rings 37, 38, 39 are fitted respectively. Is done.

Next, the cam drive gear shaft 22, the crankshaft 14b,
A cam chain chamber 42 formed by combining the base cover 40 and the outer cover 41 is provided continuously on the outer side surface of each shaft end of the idle shaft 29 protruding.

The base cover 40 has through-holes 43, 44, 45 corresponding to the through-holes 23, 27, 30 on the bottom surface 40a, and allows the protruding shaft ends to pass therethrough to press-contact the O-rings 37, 38, 39. On the outside surface.

Next, the cam driven sprocket gear 24 is fixed to the cam drive gear shaft 22 projecting into the base cover 40, and the idle sprocket gear 31 is fixed to the idle shaft 29,
Cam chain 46 between cam drive sprocket gear 26
After the chain is further extended and the chain tension 47 is assembled, the outer cover 41 is covered, and the cam chain chamber 42 is continuously provided in a sealed state. Reference numerals 48 and 49 denote fastening bolts for assembling the cam chain 42.

Thus, the rotation of the crankshaft 14b is transmitted to the cam drive gear shaft 22 via the cam chain 46 running in the cam chain 42, and the cam shaft 19 is driven as described above.

The oil in the crankcase 8 is supplied to the bearing 28 at the end of the crankshaft 14b, and a part of the oil leaks outward to form a through hole 27.
Through the crankshaft 14b and into the cam chain chamber 42 along the outer surface of the crankshaft 14b to wet the cam drive sprocket 26 and provide lubrication with the cam chain 46. It is used for lubrication between the sprocket gear 24, the idle sprocket gear 31, and the chain tensioner 47.

The oil accumulated in the cam chain 42 is appropriately returned to the oil pan. Oil is minimized for lubrication and minimizes mechanical losses. At the same time, the width of the crankcase 8, the cylinder block 9, the cylinder head 10, and the head cover 11 can be reduced by an amount corresponding to the width of the cam chain 42, so that the engine weight can be reduced.

〔The invention's effect〕

As described above, the cam chain lubricating device for a four-stroke engine according to the present invention includes the crankshaft, the camshaft or the cam drive gear shaft, and the outer ends of the idle shaft provided as necessary, such as an o-crankcase, a cylinder block, and a cylinder head. A cam chain formed of a base cover and an outer cover with an O-ring interposed around a through hole opened on each outer surface for this projection, and a crankshaft bearing. A part of the oil that has lubricated parts is introduced into this Cam Chien chamber.The Cam Chien chamber is separated from the crankcase, cylinder head, etc., and these widths can be reduced to reduce the engine weight and at the same time The machining accuracy of the crankcase and the like for attaching the cam chain to the cam chain can be relatively rough due to the arrangement of the O-ring, so that the cost can be reduced and There is an effect that can reduce the mechanical loss is suppressed to a minimum synovial oil.

[Brief description of the drawings]

FIG. 1 is a longitudinal rear view showing a main part of a motorcycle engine provided with a cam chain lubrication device according to an embodiment of the present invention;
2 is a side view of a main part of the engine of FIG. 1, FIG. 3 is a plan view of a main part of the engine of FIG. 1, and FIG. 4 is a side view of a motorcycle mounted with the engine of FIG. FIG. 1 ... Engine unit, 7 ... Cylinder, 8 ... Crank case, 9 ... Cylinder block, 10 ... Cylinder head, 14a, 14b ... Crank shaft, 19 ... Cam shaft, 20 ...
... Cam driven gear, 21 ... Cam drive gear, 22 ...
Cam drive gear shaft, 23, 27, 30 ... through hole, 24 ... cam driven sprocket gear, 26 ... cam drive sprocket gear, 28 ... crankshaft bearing, 29 ... idle shaft,
31… Idle sprocket gear, 37,38,39 …… O-ring, 40 …… Base cover, 41 …… Outer cover, 42…
… Kam Chien room, 43,44,45 …… Hole, 46… Kam Chien.

Claims (1)

(57) [Claims] A cam drive sprocket gear fixed to a crankshaft, a cam driven sprocket gear fixed to a camshaft or a cam drive gear shaft for interlocking the camshaft to transmit rotation from a crankshaft to an overhead camshaft. In a four-cycle engine in which a cam chain is mounted on an idle sprocket gear on an idle shaft provided as necessary, the crankshaft, cam shaft or cam drive gear shaft, and the shaft end of the idle shaft are replaced with a crankcase, a cylinder, An O-ring groove surrounding the through-hole is formed in the outer surface so as to protrude outward from the through-hole provided in the head and cylinder block, and an O-ring is inserted thereinto, and a through-hole through which each shaft end passes. The base cover of the open cam chain is attached to this outer surface, and each shaft end The cam drive sprocket gear, cam driven sprocket gear, and idle sprocket gear are fixed, and the outer cover is connected to the base cover to form an independent cam chain chamber. A cam chain lubricating device for a four-stroke engine, wherein the lubricating device is supplied to a cam drive sprocket gear via a cam drive sprocket gear.