JP2000337120A - Lubrication structure of outboard motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form an oil distribution passage without being limited by an engine internal part layout or without increasing an engine weight and an engine width. SOLUTION: An oil distribution passage 65 formed at the internal part of a cylinder block 10 is formed in a level between the levels of a cylinder #3 at the lowermost part of an engine 2 and a chain transmission mechanism 37. Further, a section (65b) where the oil distribution passage 65 parallels a cylinder #3 is formed in the vicinity of an intersection point between a wall part 66 where the cylinder #3 is formed as seen from the direction of a cylinder shaft C and a wall part 67 positioned right above the chain transmission mechanism 37.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lubrication structure for an outboard motor configured to supply oil to a cylinder head and other oil passages from an oil distribution passage formed inside a cylinder block of a four-cycle engine. Things.

[0002]

2. Description of the Related Art In most outboard motors equipped with a four-stroke engine, an engine is mounted vertically (in a posture in which a crankshaft stands upright) on an engine holder formed in a substantially flat plate shape, and is mounted below the engine holder. An oil pan is installed in the engine holder, and an oil pump provided in an engine holder or the like is configured to be directly driven by a camshaft or a crankshaft of the engine.

[0003] When the oil pump is driven, the oil stored in the oil pan is sucked up by the oil pump,
The oil is filtered by an oil filter and fed to the main oil gallery, where it is supplied to a crank journal (crank bearing), a connecting rod, a cylinder, a piston and the like.

[0004] A part of the oil supplied to the crank journal flows through the oil distribution passage (formed inside the cylinder block) extending from the crank journal to the cylinder head side, and a cam journal (cam) provided in the cylinder head is provided. Lubricate bearings) and valve gear.
The oil used for lubrication inside the engine is returned to the oil pan through a number of oil return holes opened on the lower surface of the engine.

[0005] In the case of a four-cycle engine, the rotation of the crankshaft is transmitted to the camshaft by a chain or a belt. However, in the case of chain transmission, a chain transmission mechanism is provided on the lower surface side of the engine, and after the engine is lubricated. Oil lubricates chains and sprockets. Further, when a chain tensioner provided along with the chain transmission mechanism is a hydraulically operated type, oil is supplied to a tension adjuster of the chain tensioner through a tensioner oil passage branched from the oil distribution passage.

[0006]

However, in such a vertically mounted engine of an outboard motor, when the above-described oil distribution passage is formed inside the cylinder block, various restrictions are imposed due to the internal layout of the engine. Receive.

That is, a plurality of cylinders and a water jacket surrounding the cylinders are formed inside the cylinder block. The oil distribution passage is formed so as not to interfere with the cylinders, the water jacket, or the chain transmission mechanism. It needs to be positioned.
In addition, the formation of the oil distribution passage tends to cause waste on the cylinder block, which may increase the engine weight and the engine width.

The oil distribution passage itself and other oil passages branched from the oil distribution passage are formed by machining such as drilling. However, the machining requires high machining accuracy, and the production cost of the engine is high. Is the cause of the increase. In addition, when the oil passage is machined inside the cylinder block, which is a casting, the oil passage communicates with a casting defect (a fine nest inside), and there is a concern that problems such as oil leakage and a decrease in oil pressure may occur. Therefore, it is desirable that the oil passages be formed by casting at the same time when the cylinder block is cast. However, if the oil passages are long, it becomes difficult to cast out the oil passages.

A lubricating structure for an outboard motor according to the present invention has been invented in order to solve the above-mentioned problems. The first object of the present invention is to provide a lubricating structure for an outboard motor without being restricted by the internal layout of the engine. An object of the present invention is to make it possible to form an oil distribution passage without increasing an engine width.

A second object of the lubricating structure for an outboard motor according to the present invention is to easily form an oil distribution passage and another oil passage receiving oil supply from the oil distribution passage.

[0011]

According to a first aspect of the present invention, there is provided a lubricating structure for an outboard motor according to the present invention. A chain transmission mechanism is mounted on the bottom of the engine and transmits the rotation of the crankshaft to the camshaft. On the other hand, an oil distribution passage is formed inside the cylinder block and branches from the crank journal to the cylinder head. In the lubricating structure for an outboard motor described above, the oil distribution passage is formed at a height between a lowermost cylinder of the engine and the chain transmission mechanism.

Further, the lubricating structure for an outboard motor according to the present invention comprises:
As described in claim 2, in the configuration of claim 1, a section of the oil distribution passage parallel to the lowermost cylinder forms a lowermost cylinder in a cylinder axial direction and the chain transmission. It was formed near the intersection with the wall located just above the mechanism.

Further, according to a third aspect of the present invention, in the lubricating structure for an outboard motor according to the third aspect, an oil is provided on at least one of the joining surface of the cylinder block and the joining surface of the cylinder head. A groove was formed in the groove, and the oil groove communicated with the oil distribution passage and another oil passage receiving oil supply from the oil distribution passage.

In the lubricating structure for an outboard motor according to the present invention, the other oil passage is formed in parallel with the oil distribution passage in the structure of the third embodiment.

Further, the lubricating structure for an outboard motor according to the present invention comprises:
As described in claim 5, in the configuration of claim 1, at least one end of the oil distribution passage is formed by casting in the cylinder block.

If the lubricating structure of the outboard motor is constructed as in claim 1, the oil distribution passage can be provided inside the cylinder block without being restricted by the position of the lowermost cylinder and the chain transmission mechanism. Thus, the degree of freedom in forming the oil distribution passage is increased.

According to the second aspect of the present invention, the oil is located in a dead space position near the intersection of the cylindrical cylinder wall and the wall immediately above the chain transmission mechanism formed in a flat plate shape. Since the section along the lowermost cylinder of the distribution passage is formed, the oil distribution passage can be formed without increasing the engine weight or the engine width.

Further, in the case of the configuration according to claim 3,
When the cylinder block and the cylinder head are joined, an oil groove formed on at least one of the joining surface of the cylinder block and the joining surface of the cylinder head is closed to form a tubular passage, and an oil distribution passage communicating with the oil groove is provided. Other oil passages communicate with each other. This makes it possible to straighten the shape of the other oil passage to facilitate its formation. Further, the oil groove itself can be formed by casting when the cylinder block or the cylinder head is cast, and it is not necessary to form the oil groove by machining, so that the oil groove can be easily provided.

If another oil passage is formed in parallel with the oil distribution passage, the workability in forming the oil distribution passage and the other oil passage by machining is improved. The formation of the oil distribution passage and other oil passages is facilitated.

Further, if at least one end of the oil distribution passage is formed by casting, the processing length can be shortened even if the remaining section of the oil distribution passage is formed by machining. The formation of the oil distribution passage is facilitated by that much.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a left side view showing an example of an outboard motor according to the present invention.

The engine 2 mounted on the uppermost part of the outboard motor 1 is, for example, an in-line three-cylinder four-stroke engine. 4 fixed above. An oil pan 5 is fixed to a lower surface of the engine holder 4, and a drive housing 6 and a gear housing 7 are sequentially fixed to a lower portion of the oil pan 5.

The engine 2 is formed by arranging a crankcase 9, a cylinder block 10, a cylinder head 11, and a head cover 12 in this order from the front, and the entire engine 2, the engine holder 4 and the oil pan 5 are part of the engine cover 13 ( (See FIG. 1).

A drive shaft 15 is rotatably connected to the lower end of the crankshaft 3 of the engine 2. The drive shaft 15 extends downward and passes through the engine holder 4, the oil pan 5, and the drive housing 6, and extends vertically. Reach within 7. A propeller shaft 16 is supported in the gear housing 7 in the horizontal (front-rear) direction, and a screw propeller 17 is integrally provided at the rear end thereof.

A bevel gear mechanism 18 and a clutch shifter 19 are provided at a portion where the drive shaft 15 intersects with the propeller shaft 16.
The screw propeller 17 rotates to generate a propulsive force. In addition, the rotation of the drive shaft 15, which always rotates in a fixed direction, is switched by the clutch shifter 19 in the forward and reverse directions, and the propeller shaft 16
And the forward and backward movements of the outboard motor 1 (hull) are selected.

At the front of the main body of the outboard motor 1 configured as described above, a clamp bracket 21 fixed to the stern plate of the boat is provided. A swivel bracket 23 is provided on the clamp bracket 21 via a tilt shaft 22,
An upper mount bracket (steering bracket) 2 is provided at an upper end and a lower end of a steering shaft 24 supported vertically and rotatably in the swivel bracket 23, respectively.
5 and a lower mount bracket 26 are provided integrally with each other.

A pair of left and right upper mount units 27 provided near the front edge of the engine holder 4 are connected to the upper mount bracket 25, and a pair of lower mount units 28 provided on both left and right sides of the drive housing 6 are provided. It is connected to the mount bracket 26. Thus, the main body of the outboard motor 1 can rotate (steer) left and right about the steering shaft 24 with respect to the clamp bracket 21 and can tilt upward about the tilt shaft 22.

FIG. 2 is an enlarged left side view of the lower portion of the engine 2, the engine holder 4 and the oil pan 5, and FIG.
FIG. 3 is a cross-sectional view of the engine 2 taken along line III-III in FIG. 2. FIG. 4 is a bottom view of the engine 2 taken along the line IV-IV in FIG. 2, and FIG. 5 is a rear view of the cylinder block 10 taken along the line VV in FIG.

As shown in FIG. 3, the cylinder block 1
The cylinder case 10 is joined and fixed to the front surface of the cylinder block 10 with a plurality of fixing bolts 31, and the joining surface 11 a of the cylinder head 11 is joined to the rear joining surface 10 a of the cylinder block 10 and fixed with a plurality of fixing bolts 32. The crankshaft 3 is rotatably supported by a plurality of (here, four in the vertical direction) crank journals formed between the crankcase 9 and the cylinder block 10, and is formed inside the cylinder head 11. A cam shaft 35 is supported by the cam journal 34. The camshaft 35 drives a valve operating device (not shown) built in the cylinder head 11.

As shown in FIG. 4, a chain transmission mechanism 37 is provided on the lower surface side of the engine 2. The chain transmission mechanism 37 is a mechanism that reduces the rotation of the crankshaft 3 by half and transmits the rotation to the camshaft 35.
Drive sprocket 3 provided integrally with the lower end of the shaft
8, a driven sprocket 39 provided at the lower end of the cam shaft 35 so as to rotate integrally therewith, and these two sprockets 3
Timing chain 40 wound around 8,39
And a chain tensioner 41 and a tension adjuster 42 for appropriately adjusting the tension of the timing chain 40, and a chain guide 43 for stabilizing the running of the timing chain 40.

The chain tensioner 41 has an arcuate shape, one end of which is rotatably supported on the lower surface of the crankcase 9 by a pivot bolt 44, and the free end of which is a timing chain 4 by a tension adjuster 42.
0 is pushed out of the chain line on the loose side. Further, the chain guide 43 is provided along the outside of the chain line on the tension side of the timing chain 40.

An adjuster box 46 (FIGS. 3 to 5) that opens downward is provided on the lower right side of the bottom of the cylinder block 10.
The tension adjuster 42 is fixed with two bolts 47 so as to close the lower opening of the adjuster box 46 in a liquid-tight manner. Oil discharged from an oil pump 55, which will be described later, is supplied into the adjuster box 46, and the presser 48 extends from the tension adjuster 42 by the oil pressure, and presses the free end side of the chain tensioner 41. As a result, the chain tensioner 41 is pressed against the slack side chain line of the timing chain 40, and the slack of the timing chain 40 is absorbed.

On the other hand, as shown in FIG. 5, three horizontal cylinders # 1 and #
2 and # 3 are formed in one vertical line, and a water jacket 51 for circulating cooling water is formed therearound.
An exhaust passage 52 is formed vertically to the left of the cylinders # 1, # 2, and # 3, and a water jacket 5 is formed around the exhaust passage 52.
3 are formed (see also FIG. 3). In addition, as shown in FIG. 4, the exhaust passage 52 opens on the lower surface of the engine 2 and further matches an exhaust passage (not shown) formed in the engine holder 4 and the drive housing 6.

A piston (not shown) is inserted into each of the cylinders # 1, # 2, and # 3. The piston is connected to a crankpin 3a (FIG. 1) of the crankshaft 3 via a connecting rod (not shown).
), And the reciprocating motion of the piston in each of the cylinders # 1, # 2, and # 3 is converted into the rotational motion of the crankshaft 3.

On the other hand, as shown in FIGS. 1 and 2, an oil pump 55 is provided at the rear of the engine holder 4. The main shaft 56 of the oil pump 55 extends upward and is rotatably fitted to the lower end of the camshaft 35 of the engine 2.
Is driven by the camshaft 35.

An oil strainer 57 extends from the suction side of the oil pump 55 and hangs down to the bottom of the oil pan 5. An oil discharge passage 58 extending from the discharge side of the oil pump 55 extends forward through the interior of the engine holder 4, the cylinder block 10 and the interior of the crankcase 9, and an oil filter chamber provided on the lower front surface of the crankcase 9. 59 (see also FIGS. 3 and 4). The oil filter 6 is provided in the oil filter chamber 59.
0 (see FIGS. 1 and 2).

As shown in FIG. 3, the oil filter chamber 5
The filter oil passage 61 extends horizontally from the outlet portion 9 and the other end is connected to the main oil gallery 62. As shown in FIG. 4, the main oil gallery 62 is formed longitudinally long along the outer surface (front surface) of the crankcase 9.

A crank oil passage 64 extending horizontally from the main oil gallery 62 is connected to the crank journal 33. Four upper and lower crank oil passages 64 are formed along the longitudinal direction of the main oil gallery 62, each corresponding to four crank journals 33.

Further, the lowermost crank journal 33
And one oil distribution passage 65 is branched. The oil distribution passage 65 passes through the inside of the cylinder block 10, and the other end is open to the rear surface of the cylinder block 10, that is, the joint surface 10 a with the cylinder head 11 (see FIGS. 5, 7, and 8). As shown in FIG. 7, the oil distribution passage 65 includes a skew section 65 a that extends obliquely (rightward) from the crank journal 33 and a parallel section 65 b that is parallel to the cylinder axis C of the engine 2. The skew section 65a and the rear half of the parallel section 65b are formed by casting when the cylinder block 10 is cast, and the front half of the parallel section 65b is machined by drilling or the like from the rear half of the parallel section 65b. It is formed.

As shown in FIG. 6, the oil distribution passage 65
Is formed at a height between the lowermost cylinder # 3 and the chain transmission mechanism 37, and the parallel section 65b is formed by a wall 66 forming the lowermost cylinder # 3 and a part immediately above the chain transmission mechanism 37. And is located diagonally below and right of the axis C of the cylinder # 3, and is parallel to the cylinder # 3.

On the other hand, as shown in FIG. 3, FIG. 5, FIG. 7, and FIG.
An oil groove 70 is provided in the groove a. This oil groove 7
An opening of an oil distribution passage 65 communicates with one end of the oil groove 70, and an opening of a tensioner oil passage 71 communicates with the other end of the oil groove 70. The tensioner oil passage 71 is an oil passage corresponding to “another oil passage” described in claim 3, and is formed by drilling or the like so as to be parallel to the oil distribution passage 65. And communicates with the adjuster box 46.

As shown in FIG. 3, the cylinder block 1
The joint surface 10a of the cylinder head 11 is
Since 1a is joined in a liquid-tight manner, the oil groove 70 formed on the joining surface 10a is closed by the joining surface 11a to form a tubular passage. Then, the oil distribution passage 65 and the tensioner oil passage 71 are relayed to the oil groove 70 and communicate with each other. In the middle of the oil groove 70, fixing bolts 3 for fastening the cylinder head 11 to the cylinder block 10 are provided.
Although the two through holes 72 intersect, the inner diameter of the outer end of the through hole 72 is set large enough so as not to reduce the cross-sectional area of the oil groove 70.

A head oil passage 74 is formed inside the cylinder head 11 (see FIG. 3). One end of the head oil passage 74 is opened to the joint surface 11 a to align with the oil distribution passage 65 (oil groove 70) of the cylinder block 10, and the other end of the head oil passage 74 is connected to the cam journal 34. An oil groove 70 is formed on the joint surface 11a side of the cylinder head 11, and a head oil passage 74 is communicated with the oil groove 70, and the joint surfaces 10a and 10a of both the cylinder block 10 and the cylinder head 11 are formed.
An oil groove 70 may be formed in 11a to align them with each other.

When the engine 2 is operated and the oil pump 55 is driven, the oil stored in the oil pan 5 is sucked into the oil pump 55 via the oil strainer 57, and the oil discharged from the oil pump 55 is The oil enters the oil filter chamber 59 through the discharge passage 58 and is filtered by the oil filter 60.

The filtered oil is supplied to each crank journal 33 through a filter oil passage 61, a main oil gallery 62, and a crank oil passage 64.
After lubricating the crank journal 33, the cam journal 34 passes through an in-shaft oil passage 75, an oil distribution passage 65, and a head oil passage 74 formed inside the crankshaft 3.
And lubricates the cam journal 34.

The oil distribution passage 65 extends from the oil groove 7
The oil is guided into the adjuster box 46 through 0 and the tensioner oil passage 71, and the tension adjuster 42 is operated by the oil pressure as described above.

Further, a part of the oil lubricating the crank journal 33 is used for lubrication of a large end of a connecting rod (not shown), and a part of the oil is further used for the inner surfaces of the cylinders # 1 to # 3, the piston (not shown), and the connecting rod. The lubrication and cooling are performed by being sprayed on the small end and the like.

As described above, the oil used for the internal lubrication and cooling of the engine 2 falls down inside the engine 2 according to the gravity, and a large number of oil return holes 76 (FIG. 4), and returns to the oil pan 5 through a number of oil holes (not shown) formed in the engine holder 4.

The lubrication structure of the outboard motor 1 is as described above. In this lubrication structure, since the oil distribution passage 65 formed inside the cylinder block 10 is formed at a height between the lowest cylinder # 3 and the chain transmission mechanism 37, the lowest cylinder # 3 and its surroundings are formed. The oil distribution passage 65 can be formed without being restricted by the position of the water jacket 51 or the chain transmission mechanism 37, and the degree of freedom in forming the oil distribution passage 65 is greatly enhanced. In this embodiment, the downstream section of the oil discharge passage 58 is also formed at the height between the lowermost cylinder # 3 and the chain transmission mechanism 37, and the degree of freedom in forming the oil discharge passage 58 is also increased. I have.

The parallel section 65 of the oil distribution passage 65
b is formed near the intersection of the wall 66 forming the lowermost cylinder # 3 and the wall 67 located immediately above the chain transmission mechanism 37, so that the cylindrical wall 66 and the flat wall are formed. The parallel section 65b is located at a dead space-like position of a wedge-shaped cross-section near the intersection with the portion 67, whereby the oil distribution passage 65 can be formed without increasing the engine weight or the engine width.

On the other hand, the joining surface 1 of the cylinder block 10
Oil distribution passage 6 is formed by oil groove 70 recessed in
5 (parallel section 65b) and the tensioner oil passage 71 are communicated with each other, so that the tensioner oil passage 71 can be formed into a very simple straight passage, and the processing thereof can be facilitated. In addition, since the tensioner oil passage 71 is formed parallel to the oil distribution passage 65, when the tensioner oil passage 71 is formed by machining such as drilling, the oil distribution passage 6 is formed.
5 (the first half of the parallel section 65b) can be machined at the same time as the machining, and in this respect too, the formation of the tensioner oil passage 71 is easy. The oil groove 70 itself is
Cylinder block 10 without depending on machining
Since it is possible to form a blank at the time of casting, it can be provided very easily.

Further, the skew section 6 of the oil distribution passage 65
5a and the latter half of the parallel section 65b are cast and formed at the same time as the casting of the cylinder block 10, so that only the short length of the first half of the parallel section 65b depends on machining, and thus the oil Since the length of the distribution passage 65 to be machined is short, the oil distribution passage 65 can be easily formed.
The probability of occurrence of a problem such as oil leakage or a decrease in oil pressure due to communication with a casting defect portion inside 0 is also reduced. Although it is ideal that the both ends of the oil distribution passage 65 are formed by casting as described above, it is effective to cast and form only one end of the oil distribution passage 65.

Further, in this embodiment, the adjuster box 46 and the tensioner oil passage 71 are formed on the cylinder block 10 side, but both may be formed on the cylinder head 11 side. In this embodiment, the tensioner oil passage 71 is described as an example of an oil passage that receives oil supply from the oil distribution passage 65. However, another oil passage is communicated with the oil groove 70 to allow oil to flow from the oil distribution passage 65. May be supplied. Further, the oil passage communicating with the oil groove 70 has one
The number of oil passages is not limited to
May be communicated with.

[0054]

As described above, according to the lubrication structure for an outboard motor according to the present invention, the oil distribution passage can be formed without being restricted by the internal layout of the engine and without increasing the engine weight or the engine width. In addition to being able to form, the oil distribution passage and another oil passage receiving the oil supply from the oil distribution passage can be easily formed.

[Brief description of the drawings]

FIG. 1 is a left side view showing an example of an outboard motor according to the present invention.

FIG. 2 is an enlarged left side view of a lower portion of an engine, an engine holder, and an oil pan.

FIG. 3 is a cross-sectional view of the engine taken along line III-III in FIG. 2;

FIG. 4 is a bottom view of the engine taken along the line IV-IV in FIG. 2;

FIG. 5 is a rear view of the cylinder block as viewed in the direction of arrows VV in FIG. 1;

FIG. 6 is a view showing one embodiment of the present invention by a longitudinal section along the line VI-VI in FIG. 3;

FIG. 7 is an enlarged view of an oil distribution passage, an oil groove, an adjuster box, a tensioner oil passage and the like.

FIG. 8 is an enlarged view of a portion VIII in FIG. 5;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Outboard motor 2 Engine 3 Crankshaft 4 Engine holder 5 Oil pan 9 Crankcase 10 Cylinder block 10a Cylinder block joint surface 11 Cylinder head 11a Cylinder head joint surface 33 Crank journal 35 Camshaft 37 Chain transmission mechanism 55 Oil pump 62 Main oil gallery 65 Oil distribution passage 65a Oblique section of oil distribution passage 65b Parallel section of oil distribution passage 66, 67 Wall 70 Oil groove 71 Tensioner oil passage receiving oil supply from oil distribution passage # 3 Lowermost cylinder

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3G013 AA03 AA05 AA07 AB01 BA02 BB07 BB19 BC01 BC03 BC04 BC20 BD01 BD06 BD07 BD09 BD14 BD27 BD41

Claims (5)

[Claims] 1. A four-stroke engine is mounted vertically with its crankshaft upright, and a chain transmission mechanism for transmitting rotation of the crankshaft to a camshaft is provided on a lower surface side of the engine, while a cylinder block is provided. In an outboard motor lubrication structure in which an oil distribution passage branched from a crank journal and leading to a cylinder head is formed inside the oil distribution passage 65, the oil distribution passage 65 is connected to the lowermost cylinder # 3 of the engine 2 and the chain transmission mechanism 37. An outboard motor lubrication structure characterized by being formed at a height between the two. 2. A section (65b) of the oil distribution passage 65 that is parallel to the lowermost cylinder # 3 is formed with a wall 6 that forms the lowermost cylinder # 3 when viewed in the cylinder axial direction.
The lubricating structure for an outboard motor according to claim 1, wherein the lubricating structure is formed near an intersection of a wall portion (6) and a wall (67) located immediately above the chain transmission mechanism (37). 3. The joining surface 1 of the cylinder block 10.
0a and at least one of the joining surfaces 11a of the cylinder head 11, an oil groove 70 is formed in the oil groove 70, and the oil distribution passage 65 and the oil distribution passage 6 are formed in the oil groove 70.
The lubricating structure for an outboard motor according to claim 1, wherein another oil passage (71) that receives an oil supply from the oil passage (5) is communicated. 4. The outboard motor lubrication structure according to claim 3, wherein said another oil passage is formed in parallel with said oil distribution passage. 5. The lubricating structure for an outboard motor according to claim 1, wherein at least one end of said oil distribution passage 65 is formed by casting in said cylinder block 10.