JP3870737B2 - Oil return structure for outboard motor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an oil return structure for an outboard motor.
[0002]
[Prior art]
An outboard motor is generally equipped with an engine with a crankshaft arranged vertically. Such an engine is configured by combining engine components such as a cylinder block and a crankcase, for example, and the cylinder block is disposed on the side of the crankcase. The cylinder block has a cylindrical sleeve (cylinder) extending in the horizontal direction, and a cylinder head is disposed further to the side of the cylinder block. A crank chamber is formed between the crankcase and the cylinder block, and the crank chamber is partitioned in the vertical direction for each cylinder by a partition wall. An oil pan is arranged at the bottom of the engine.
[0003]
A crankshaft is vertically arranged on the joint surface between the crankcase and the cylinder block, and each journal portion of the crankshaft is a bearing formed on the mating surface of the cylinder block and the crankcase via a bearing. It is pivotally supported by the boss.
[0004]
In general, the lubricating oil for lubricating the crankshaft or the like is pumped to the upper part of the engine by an oil pump, and then naturally falls inside the engine and is collected in an oil pan.
[0005]
The engine for outboard motors with the crankshaft arranged vertically prevents oil from falling into the uppermost crank chamber so that the bulkhead prevents the lubricating oil from falling naturally, and the oil pits in the partition that also serves as the bearing boss of the crankshaft And an oil drop groove is provided to guide the lubricating oil to the oil pan.
[0006]
[Problems to be solved by the invention]
However, if the oil drop from the crank chamber is insufficient, the lubricating oil accumulates in the crank chamber, and the accumulated lubricating oil, for example, the web of the crankshaft stirs. When the web agitates the lubricating oil, the resistance increases (increase in mechanical loss), causing a decrease in engine output, which is not preferable.
[0007]
Also, if the oil drop is insufficient, there is a risk that the lubricating oil in the oil pan will run short and air will be sucked in, so it is necessary to increase the capacity of the oil pan and increase the amount of lubricating oil. However, this is not preferable because it involves an increase in the size and weight of the engine.
[0008]
Therefore, there is a method of enlarging an oil drop hole and an oil drop groove provided in the partition wall. However, since the partition wall also serves as a bearing boss of the crankshaft, sufficient rigidity of the cylinder block and the crankcase cannot be secured.
[0009]
On the other hand, for example, in the case of a V-type engine for an outboard motor in which left and right integrated cylinder blocks are arranged in a V shape in plan view, the left and right sleeves share one crank chamber, but one sleeve is Since the offset is disposed in the direction, the wrap between the sleeve disposed on the lower side and the partition wall becomes large, and the lubricating oil in the lower sleeve is difficult to drop.
[0010]
The present invention has been made in consideration of the above-described circumstances, and an object thereof is to provide an oil return structure for an outboard motor that ensures sufficient rigidity of the crankcase and improves the dropping performance of the lubricating oil. To do.
[0011]
[Means for Solving the Problems]
In order to solve the above-described problem, an oil return structure for an outboard motor according to the present invention has a left-right integrated cylinder block arranged in a V shape in plan view, as described in claim 1, In an outboard motor having a V-type engine having a cylindrical sleeve and a crankshaft arranged vertically on the joint surface between the cylinder block and the crankcase, a crank is interposed between the crankcase and the cylinder block. Forming a chamber and partitioning the crank chamber in the vertical direction for each cylinder by a partition wall, and providing a dedicated oil drop passage communicating with the crank chamber outside the crank chamber, the crank chamber and the oil drop passage The outlet of the sleeve is disposed in the vicinity of the crank chamber side end of one of the sleeves, and the end of the sleeve is connected to the outlet. With use as a guide portion of the lubricating oil, it is obtained by forming an oil trap for communicating between the upper and lower sleeve to the crank chamber side end portion of each sleeve.
[0012]
In order to solve the above-described problem, as described in claim 2, the lower edge portion of the outlet that communicates the crank chamber and the oil dropping passage is substantially the same as the upper surface of the partition wall. Is formed.
[0013]
Furthermore, in order to solve the above-mentioned problem, as described in claim 3, the sleeve on the side where the outflow port is disposed is disposed offset above the partition wall, and a space is provided below the sleeve. Secured.
[0014]
Still further, in order to solve the above-described problem, as described in claim 4, the crank chamber and the engine lower portion are disposed in the space below the sleeve disposed offset above the crank chamber disposed in the lowermost portion. The oil drain port that communicates with the space is formed.
[0015]
In order to solve the above-described problem, as described in claim 5, a sleeve disposed on the side opposite to the side where the oil dropping passage is disposed is offset below the partition wall, and the sleeve In the boundary portion between the crank chamber side end and the partition wall, an oil pit is formed on the partition wall side to the lower crank chamber, and the lowermost sleeve is connected to the space below the engine.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0017]
FIG. 1 is a left side view showing an embodiment of an outboard motor to which the present invention is applied. As shown in FIG. 1, the outboard motor 1 includes an engine holder 2, and an engine 3 is installed above the engine holder 2. The engine 3 is a vertical type engine in which the crankshaft 4 is disposed substantially vertically.
[0018]
An oil pan 5 for storing lubricating oil (not shown) is disposed below the engine holder 2, and a bracket device 6 is attached to the outboard motor 1, for example, and the outboard motor is interposed via the bracket device 6. 1 is attached to a transom of a ship (not shown). Further, the engine 3, the engine holder 2 and the oil pan 5 are covered with an engine cover 7.
[0019]
A drive shaft housing 8 is installed below the oil pan 5. A drive shaft 9 that is an output shaft of the engine 3 is disposed substantially vertically in the engine holder 2, the oil pan 5, and the drive shaft housing 8, and an upper end portion thereof is connected to a lower end portion of the crankshaft 4. The drive shaft 9 extends downward in the drive shaft housing 8 and drives a propeller 13 as a propulsion device via a bevel gear 11 and a propeller shaft 12 in a gear case 10 provided at a lower portion of the drive shaft housing 8. Composed.
[0020]
FIG. 2 is a plan view of the engine 3 and a part thereof is shown in cross section. As shown in FIGS. 1 and 2, the engine 3 of the outboard motor 1 is a water-cooled four-cycle V-type six-cylinder engine configured by combining, for example, a cylinder head 14, a cylinder block 15, a crankcase 16, and the like. By arranging the left and right cylinder blocks 15 in a V shape in plan view, a V bank is formed between the cylinder blocks 15.
[0021]
A left and right cylinder block 15 is arranged in a V-shape extending in the width direction of the outboard motor 1 at the foremost part of the engine 3, behind the crankcase 16 arranged on the leftmost side in FIGS. Is done. A cylinder head 14 is disposed behind each cylinder block 15.
[0022]
FIG. 3 is a view taken in the direction of arrow III in FIG. 2 and shows a right side view of the cylinder block 15 and the crankcase 16. 4 is a cross-sectional view taken along the line IV-IV in FIG. 3 and is a view as seen from the joint surface of the cylinder block 15 with the crankcase 16. 5 is a cross-sectional view taken along the line VV in FIG. 2, and FIG. 6 is a cross-sectional view taken along the line VI-VI in FIG. FIG. 7 is a view taken in the direction of arrow VII in FIG. 5, that is, a bottom view of the engine 3.
[0023]
As shown in FIGS. 2 to 6, three cylindrical sleeves 17 (cylinders) are formed in each cylinder block 15 so as to be arranged substantially horizontally in the vertical direction, and a piston 18 is provided in each sleeve 17. It is slidably inserted in the axial direction on the axis of the sleeve 17. A crank chamber 19 is formed between the crankcase 16 and the cylinder block 15, and the crank chamber 19 is partitioned in the vertical direction for each cylinder by a partition wall 20. Each crank chamber 19 is shared by a pair of left and right sleeves 17.
[0024]
The crankshaft 4 is arranged vertically on the joint surface between the crankcase 16 and the cylinder block 15, and each journal portion 4 a of the crankshaft 4 is interposed between the cylinder block 15 and the crankcase 16 through the bearing 21. It is pivotally supported by a bearing boss 20a formed on the mating surface. Further, the crankshaft 4 and the piston 18 are connected by a connecting rod 22 so that the reciprocating stroke of the piston 18 is converted into the rotational motion of the crankshaft 4.
[0025]
A combustion chamber 23 that is aligned with the sleeve 17 is formed in the cylinder head 14, and a spark plug 24 is coupled from the outside thereof. An intake port 25 and an exhaust port 26 connected to the combustion chamber 23 are also formed in the cylinder head 14. As shown in FIG. 2, the exhaust port 26 is connected to an exhaust passage 27 formed outside the left and right cylinder heads 14, and the intake port 25 is formed inside the left and right cylinder heads 14 and the cylinder block 15. Extends into the bank.
[0026]
Further, an intake valve 28 and an exhaust valve 29 that open and close both ports 25 and 26 are disposed in each cylinder head 14, and two valve operating valves that open and close these valves 28 and 29 are disposed at the rear of the cylinder head 14. A camshaft 30 (for intake and exhaust) is arranged parallel to the crankshaft 4. The cylinder head 14 is covered with a cylinder head cover 31. Further, as shown in FIG. 5, the upper end of the crankshaft 4 protrudes above the engine 3, and a flywheel 32 and a power generating magnet device 33 are provided at the protruding portion.
[0027]
On the other hand, a camshaft drive mechanism 34 that transmits the rotation of the crankshaft 4 to the camshaft 30 to rotationally drive the camshaft 30 is provided below the engine 3. This camshaft drive mechanism 34 is, for example, a chain drive system. As shown in FIGS. 6 and 7, the timing sprocket 35 provided at the lower end of the crankshaft 4 and the cam sprocket provided at the lower end of the camshaft 30. 36, a timing chain 37 wound around the sprockets 35 and 36, and the like are main constituent members.
[0028]
The engine 3 is provided with a lubrication device. The lubricating device pumps the lubricating oil stored in the oil pan 5 to each part of the engine 3 by an oil pump 38 provided coaxially with the crankshaft 4 at the lower portion of the crankshaft 4 and finally the oil pan. 5 is collected.
[0029]
Lubrication in the crank chamber 19 and the piston 18 is, for example, pumped by the oil pump 38 through the oil filter 39 and the main gallery 40 to the oil jet 41 directed to the upper part of the engine 3 and each sleeve 17. A sliding contact surface between the journal portion 4a of the crankshaft 4 and the bearing 21, the crankpin 4b and the connecting rod 22, the sleeve 17 and the piston 18 and the like through an oil passage (not shown) formed in the crankshaft 4. Guided to the contact surface.
[0030]
Lubricating oil that has lubricated each sliding contact portion is discharged into the crank chamber 19 and the sleeve 17. The outboard motor 1 according to the present invention has the crankshaft 4 disposed vertically and the sleeve 17 disposed horizontally. The engine 3 for use in the engine 3 has a partition wall 20 that defines the crank chamber 19 to prevent the lubricating oil from falling naturally, so that the lubricating oil does not accumulate in the crank chamber 19 and the sleeve 17, for example, on the wall of the cylinder block 15. An oil drop passage 42 is provided in the section, and is configured to guide the lubricating oil to the oil pan 5.
[0031]
When the crankshaft 4 is rotated, the web 4c of the crankshaft 4 agitates the lubricating oil accumulated in the crank chamber 19, and the lubricating oil flows. When the walls of the cylinder blocks 15 of the upper two crank chambers 19 located downstream of the flow of the lubricating oil, for example, the crankshaft 4, rotate clockwise, the right side in the traveling direction of the outboard motor 1 (FIG. 2). In the left side), an outlet 43 for communicating the inside of the crank chamber 19 with the outside is formed. These outlets 43 are not formed in the lowermost crank chamber 19.
[0032]
These outflow ports 43 are formed so that the lower edge portions thereof are substantially the same as the upper surface of the partition wall 20, and the lubricating oil accumulated in the upper two crank chambers 19 is smoothly discharged out of the crank chambers 19. Is done. Further, a space 44 connected to the oil pan 5 is formed at the lower part of the engine 3, that is, below the lowermost crank chamber 19 with the lowermost partition wall 20 as a boundary, and the lowermost part on the side where the outlet 43 is provided. An inlet 45 is formed in the wall of the cylinder block 15 of the crank chamber 19 to communicate the space 44 below the engine 3 with the outside.
[0033]
The outlet 43 and the inlet 45 described above are covered with a cover 46 to form the oil drop passage 42 described above. That is, the lubricating oil that lubricates each sliding contact portion of the engine 3 and flows into the upper two crank chambers 19 is guided from the outlet 43 through the oil dropping passage 42 to the space 44 below the engine 3 from the inlet 45. Fall on pan 5. Further, since the outlet 43 is not formed in the lowermost crank chamber 19, a large amount of lubricating oil that falls from above does not flow into the crank chamber 19.
[0034]
As shown in FIGS. 2 and 4, the sleeve 17 on the side where the outlet 43 is disposed (the downstream side of the flow of the lubricating oil stirred by the web 4 c of the crankshaft 4) is disposed offset above the partition wall 20. A space 47 is secured below the sleeve 17. The outlet 43 is disposed in the vicinity of the end of the sleeve 17 on the crank chamber 19 side, and the end of the sleeve 17 serves as a guide for lubricating oil to the outlet 43, and the lubricating oil in the crank chamber 19 enters the sleeve 17. Prevent inflow.
[0035]
As shown in FIG. 4, a space 47 provided below the sleeve 17 on the side where the oil dropping passage 42 is disposed in the crank chamber 19 positioned at the lowermost portion is a space between the inside of the crank chamber 19 and the lower portion of the engine 3. An oil discharge port 48 that communicates with 44 is formed to guide the lubricating oil accumulated in the lowermost crank chamber 19 to the oil pan 5.
[0036]
Further, as shown in FIGS. 4, 5, and 7, the sleeves 17 disposed on the side opposite to the side on which the oil dropping passage 42 is disposed are disposed to be offset downward from the partition wall 20. An oil drop hole 49 connected to the lower crank chamber 19 is formed on the partition wall 20 side of the boundary portion between the crank chamber 19 side end and the partition wall 20 and to the space 44 below the engine 3 in the lowermost sleeve 17. The
[0037]
2, 5, and 7, among the sleeves 17 that are arranged to be offset downward from the partition wall 20, the upper sleeve 17 excluding the sleeve 17 that is disposed at the lowermost portion is on the crank chamber 19 side. An oil drop hole 50 that communicates between the upper and lower sleeves 17 is formed at the end portion, and the lubricating oil accumulated in the upper sleeve 17 is guided to the lowermost sleeve 17, and the boundary between the end portion on the crank chamber 19 side and the partition wall 20. Return to the oil pan 5 through the oil pit 49 formed in the portion.
[0038]
On the other hand, as shown in FIGS. 2, 5, and 6, an oil dropping hole 51 that communicates between the upper and lower sleeves 17 is also formed at the end of the sleeve 17 that is offset above the partition wall 20 on the crank chamber 19 side. The lubricating oil accumulated in the upper sleeve 17 is returned to the oil pan 5.
[0039]
Next, the operation of this embodiment will be described.
[0040]
When the engine 3 is started and the crankshaft 4 rotates, an oil pump 38 driven by the crankshaft 4 pumps up lubricating oil in the oil pan 5 and pumps it to each part in the engine 3.
[0041]
The lubricating oil that has lubricated the journal portion 4a of the crankshaft 4 and the sliding contact surface of the bearing 21 via an oil passage (not shown) formed in the crankshaft 4 from the main gallery 40 is provided in each crank chamber 19. It accumulates on the upper surface of the partition wall 20 and is stirred, for example, clockwise by the web 4c of the crankshaft 4.
[0042]
On the other hand, the lubricating oil guided from the main gallery 40 through the oil jet 41 to the sliding contact surface between the sleeve 17 and the piston 18 and into the piston 18 is collected at the end of the sleeve 17 on the crank chamber 19 side.
[0043]
As in the prior art, the partition wall 20 that also serves as the bearing boss 20a of the crankshaft 4 is not provided with an oil drop hole or an oil drop groove, or is small even if provided, and a dedicated oil drop passage 42 is provided outside the crank chamber 19. As a result, the oil drop from the crank chamber 19 can be sufficiently prevented, an increase in mechanical loss can be prevented, the amount of lubricating oil need not be increased, and the rigidity of the cylinder block 15 and the crankcase 16 constituting the partition wall 20 can be sufficiently increased. It can be secured.
[0044]
In addition, the sleeve 17 on the side where the outflow port 43 communicating with the oil dropping passage 42 is disposed is offset above the partition wall 20, and the outflow port 43 is disposed near the end of the sleeve 17 on the crank chamber 19 side, By using the end portion of the sleeve 17 as a guide portion of the lubricating oil to the outlet 43, the lubricating oil in the crank chamber 19 can be prevented from flowing into the sleeve 17, and the lubricating oil to the oil dropping passage 42 can be prevented. The inflow efficiency is improved.
[0045]
Further, the oil drop holes 50 and 51 that communicate between the upper and lower sleeves 17 are formed at the end of each sleeve 17 on the crank chamber 19 side, and the lubricating oil accumulated in the sleeve 17 is returned to the oil pan 5. Further, it is not necessary to form an oil drop hole or an oil drop groove in the partition wall 20 that also serves as the bearing boss 20a of the crankshaft 4, and the rigidity of the cylinder block 15 and the crankcase 16 is not lowered.
[0046]
Further, the positions of the oil drop holes 50 and 51 described above do not affect the ring 18a and the skirt portion 18b of the piston 18 as shown in FIGS.
[0047]
The outflow port 43 communicating the inside of the crank chamber 19 and the oil dropping passage 42 is formed so that the lower edge portion thereof is substantially the same as the upper surface of the partition wall 20, so that the lubricating oil accumulated in the crank chamber 19 is cranked. It is smoothly discharged out of the chamber 19.
[0048]
Further, by arranging the sleeve 17 on the side where the outflow port 43 is arranged offset above the partition wall 20, a space 47 is secured below the sleeve 17, and the outflow port 43 is further connected to the crank chamber 19 of the sleeve 17. By arranging in the vicinity of the side end, the end portion of the sleeve 17 can be used as a guide portion of the lubricating oil to the outlet port 43, and the inflow of the lubricating oil in the crank chamber 19 into the sleeve 17 is prevented.
[0049]
Furthermore, the outlet 43 that connects the inside of the crank chamber 19 and the oil dropping passage 42 is not formed in the lowermost crank chamber 19, and the sleeve that is offset upward is disposed on the side where the oil dropping passage 42 is disposed. 17 is formed in a space 47 provided below, and an oil discharge port 48 for communicating the inside of the crank chamber 19 and the space 44 below the engine 3 is formed, and the lubricating oil accumulated in the lowermost crank chamber 19 is guided to the oil pan 5. By doing so, a large amount of lubricating oil does not flow into the lowermost crank chamber 19 from the upper crank chamber 19 via the oil drop passage 42, and mechanical loss is reduced and the inside of the crank chamber 19 is reduced. The lubricating oil can be prevented from flowing into the sleeve 17.
[0050]
Further, the sleeve 17 that is offset downward from the partition wall 20 is moved to the lower crank chamber 19 on the partition wall 20 side at the boundary between the crank chamber 19 side end and the partition wall 20, and the lowermost sleeve 17 By forming the oil drop holes 49 connected to the space 44 below the engine 3, it is difficult for the lubricating oil in the lower sleeve 17 to fall due to the large wrap between the sleeve 17 and the partition wall 20 arranged on the lower side. The problem can be solved.
[0051]
【The invention's effect】
As described above, according to the oil return structure for an outboard motor according to the present invention, the oil drop from the crank chamber becomes sufficient, an increase in mechanical loss can be prevented, and the rigidity of the crankcase can be sufficiently secured.
[0052]
Further, the lubricating oil in the crank chamber is prevented from flowing into the sleeve.
[0053]
Furthermore, the lubricating oil in the sleeve that is offset below the partition wall is likely to drop.
[Brief description of the drawings]
FIG. 1 is a left side view of an outboard motor showing an embodiment of an oil return structure for the outboard motor according to the present invention.
FIG. 2 is a plan view of the engine.
FIG. 3 is a view taken in the direction of arrow III in FIG.
4 is a cross-sectional view taken along the line IV-IV in FIG. 3;
5 is a cross-sectional view taken along line VV in FIG.
6 is a cross-sectional view taken along line VI-VI in FIG.
7 is a view taken along arrow VII in FIG. 5;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Outboard motor 3 V type engine 4 Crankshaft 5 Oil pan 15 Cylinder block 16 Crankcase 17 Sleeve 18 Piston 19 Crank chamber 20 Bulkhead 42 Oil drop passage 43 Outlet 47 Space below sleeve 48 Oil drain port 49 Oil drop hole 50 Oil Pitfall 51 Oil Pitfall

Claims (5)

A V-type engine in which left and right integrated cylinder blocks are arranged in a V shape in a plan view, a cylindrical sleeve is provided in the cylinder block, and a crankshaft is vertically arranged on a joint surface between the cylinder block and the crankcase. In the outboard motor provided, a crank chamber is formed between the crankcase and the cylinder block, the crank chamber is vertically partitioned for each cylinder by a partition, and the crank chamber is formed outside the crank chamber. While providing a dedicated oil drop passage for communication, an outlet for connecting the crank chamber and the oil drop passage is disposed near the crank chamber side end of one of the sleeves, and the end of the sleeve is connected to the outlet. The upper and lower sleeves are used as guide portions for the lubricating oil of the sleeves and at the crank chamber side ends of the sleeves. Oil return structure of the outboard motor, characterized in that the formation of the oil pitfalls communicating. 2. The oil return structure for an outboard motor according to claim 1, wherein a lower edge portion of the outlet that communicates the crank chamber and the oil dropping passage is formed to be substantially the same as an upper surface of the partition wall. The oil return structure for an outboard motor according to claim 1 or 2, wherein the sleeve on the side where the outflow port is disposed is offset above the partition wall and a space is secured below the sleeve. The outboard motor according to claim 3, wherein an oil discharge port that connects the crank chamber and the space below the engine is formed in the space below the sleeve disposed offset above the crank chamber disposed at the lowermost portion. Oil return structure. A sleeve disposed on the side opposite to the side on which the oil dropping passage is disposed is offset below the partition wall, and is positioned below the partition wall side of the boundary between the crank chamber side end of the sleeve and the partition wall. The oil return structure for an outboard motor according to claim 3 or 4, wherein an oil pit for connecting to the space under the engine is formed in the lowermost sleeve, respectively.

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