JP2004237846A - Outboard motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the oil kept in an oil pan and an engine mount from being influenced by a thermal disaster caused by discharged heat. <P>SOLUTION: An inner side of an oil pan block 4 is divided into a plurality of compartments. One of the compartments is applied as a discharging compartment 67 and this chamber is communicated with a main discharging passage (a discharging pipe 77). The other compartment is applied as an oil pan 68. The discharging compartment 67 is provided with a cooling water storage part 88 enclosing a circumference of the main discharging passage. A part of the engine cooling water is passed through the cooling water storage part 88 and the cooling water is filled in the cooling water storage part 88. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an outboard motor configured to avoid heat damage of exhaust gas.
[0002]
[Prior art]
For example, as described in JP-A-5-278684 (see Patent Document 1) and JP-A-9-41930 (see Patent Document 2), a four-cycle V-type engine is mounted vertically. Many conventional outboard motors have a layout in which main exhaust passages extend vertically on the left and right sides of an engine holder on which an engine is mounted, and an oil pan is interposed between the main exhaust passages.
[0003]
Further, as disclosed in Japanese Patent Application Laid-Open No. 9-41930, a release exhaust passage for discharging exhaust gas to the outside when the ship is stopped utilizes a space defined between the engine holder and the drive shaft housing. And was provided at a relatively low position.
[0004]
[Patent Document 1]
JP-A-5-278684
[Patent Document 2]
JP-A-9-41930
[Problems to be solved by the invention]
However, since the oil pan is interposed between the main exhaust passages on the left and right sides as described above, there is a problem that the oil temperature in the oil pan is likely to increase due to the exhaust heat.
[0007]
Similarly, the exhaust heat is easily transmitted to the engine holder that connects the outboard motor's fuselage and the clamp bracket that is a fixing part to the stern side, and the deterioration of the engine mount having the rubber bush is accelerated. There was a tendency.
[0008]
In addition, since the release exhaust passage is provided at a relatively low position, when the draft position of the hull is high, the water pressure applied to the outlet of the release exhaust passage increases, and, for example, when a wake is detected during a low speed navigation, the engine stops. And so on.
[0009]
Furthermore, in many conventional outboard motors, the cooling water after cooling the engine merges into the main exhaust passage (exhaust expansion chamber) at almost the level of an oil pan, so that the merging position is high. There has been a problem that the exhaust gas easily entrains water, and as a result, water is released from the release exhaust passage to generate noise.
[0010]
SUMMARY OF THE INVENTION The present invention has been made to solve these problems, and it is intended to prevent heat damage caused by exhaust heat to oil in an oil pan and an engine mount, to smooth release exhaust, and to provide a release exhaust passage. The purpose of the present invention is to provide an outboard motor capable of preventing the discharge of water from the engine, and at the same time, making the engine compact and reducing the number of parts, and improving the assemblability, maintainability, manufacturability and layout. I do.
[0011]
[Means for Solving the Problems]
In order to achieve the above object, an outboard motor according to the present invention has an engine holder, an oil pan block, and a drive shaft housing which are sequentially assembled to a lower portion of an engine, and exhaust gas of the engine is reduced. In an outboard motor configured to be guided to an exhaust expansion chamber inside the drive shaft housing through a main exhaust passage provided inside the engine holder and the oil pan block, the inside of the oil pan block may be divided into a plurality of sections. The main exhaust passage is provided with one of the rooms as an exhaust chamber, and the other is an oil pan.
[0012]
According to the above configuration, since the exhaust chamber and the oil pan are partitioned, it is difficult for the exhaust heat to be transmitted to the oil pan, so that an increase in the oil temperature in the oil pan due to the exhaust heat can be prevented.
[0013]
The outboard motor according to the present invention, as described in claim 2, partitions the inside of the oil pan block into front and rear, arranges the main exhaust passage with a front room as the exhaust chamber, and The above-mentioned room is the oil pan, and the exhaust chamber is provided with a cooling water storing portion surrounding the periphery of the main exhaust passage, and the cooling water storing portion is filled with the cooling water through a part of the engine cooling water.
[0014]
With the above configuration, since the cooling water is filled in the cooling water reservoir surrounding the periphery of the main exhaust passage, the exhaust heat is insulated from the oil pan, so that the oil temperature in the oil pan due to the exhaust heat is further increased. It can be effectively prevented.
[0015]
Further, in the outboard motor according to the present invention, as described in claim 3, the exhaust chamber of the oil pan block is formed in a box shape with a bottom, and the exhaust block formed separately from the oil pan block is exhausted. It is installed in a room, the main exhaust passage is formed inside the exhaust block, and the cooling water storage portion is provided between the periphery of the exhaust block and the inner wall of the exhaust chamber. The structure around the main exhaust passage can be made compact to improve the assemblability, and the oil pan block can be made easier by eliminating the hollow shape.
[0016]
In the outboard motor according to the present invention, a rising cooling water chamber and a release exhaust expansion chamber are formed inside the exhaust block, and the rising cooling water chamber is filled with cooling water. This feature contributes to efficient cooling of the main exhaust passage, downsizing around the exhaust block, and reduction in the number of parts.
[0017]
Also, in the outboard motor according to the present invention, as described in claim 5, an engine mount provided on the engine holder is arranged above at least one of the cooling water storage part and the rising cooling water chamber. Because of this feature, the heat of the exhaust gas is less likely to be transmitted to the engine mount by passing through the engine holder, so that early deterioration of the engine mount can be avoided.
[0018]
Furthermore, the outboard motor according to the present invention is characterized in that the release exhaust passage is formed inside the engine holder as described in claim 6, so that the position of the release exhaust passage is increased, and Even when the draft position is high, it is difficult for water to flow into the release exhaust passage, and the release exhaust can be smoothly performed.
[0019]
Further, in the outboard motor according to the present invention, as described in claim 7, the outlet of the cooling water flowing-down passage after cooling the engine is provided on the opposite side to the exhaust chamber with the oil pan interposed therebetween. According to this, according to this, an oil pan is interposed between the outlet of the downflow passage and the main exhaust passage, and as a result, the position where the cooling water that has finished cooling the engine merges with the exhaust gas is higher than that of the oil pan. Since the lower position is lower, it is difficult for the exhaust gas to entrain water, and it is difficult for water to be released from the release exhaust passage. As a result, it is possible to prevent water from being released from the release exhaust passage.
[0020]
The outboard motor according to the present invention is characterized in that a release exhaust passage and a flush passage for cleaning a cooling water passage are opened at a rear portion of the engine holder, as described in claim 8. According to this, both the release exhaust passage and the flush passage are opened rearward, so that maintenance and layout can be improved.
[0021]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0022]
FIG. 1 is a left side view showing an example of an outboard motor according to the present invention. The outboard motor 1 has an engine 2 mounted on the top thereof, an engine holder 3, an oil pan block 4, a drive shaft housing 5 and a lower housing 6 assembled in order below the engine 2. 5 is covered with an upper cover 8, a middle cover 9, and a lower cover 10 made of synthetic resin.
[0023]
The engine 2 is, for example, a water-cooled four-cycle V-type six-cylinder type. The engine 2 is arranged so that its crankshaft 12 is vertically oriented with the crankcase 13 on the front side and the pair of left and right cylinder heads 14 on the rear side. It is fixed on the holder 3.
[0024]
The rotation of the crankshaft 12 is reduced by the drive gear 16 and the driven gear 17 and transmitted to the drive shaft 18. The rotation of the drive shaft 18 is transmitted to the propeller shaft 20 and the propeller 21 via the bevel gear mechanism 19. Then, the rotation of the drive shaft 18, which always rotates in one direction, is switched between forward and reverse by the forward / reverse switching mechanism 22 to move the hull forward or backward.
[0025]
The engine holder 3 and the drive shaft housing 5 are provided with a pair of left and right engine mounts 24 and 25, respectively. As shown in FIGS. 2 and 3, the upper engine mount 24 is connected to the upper steering bracket 26, The engine mount 25 on the side is connected to the lower steering bracket 27. The engine mount 24 has a configuration in which an anchor bolt 29 is inserted into a cylindrical rubber cushion 28.
[0026]
The upper steering bracket 26 and the lower steering bracket 27 are respectively rotatably fixed to the upper end and the lower end of a vertically extending pilot shaft 31. Is supported by a clamp bracket 34, and the clamp bracket 34 is fixed to the stern 35 of the hull.
[0027]
A linkage of a steering device (not shown) is connected to the upper steering bracket 26 so that the outboard motor 1 is steered. A power tilt and trim mechanism (not shown) for adjusting the angle of the outboard motor 1 with respect to the hull is provided near the clamp bracket 34.
[0028]
3 is a top view of the engine holder 3 taken along the line III-III of FIG. 2, FIG. 4 is a bottom view of the engine holder 3 taken along the line IV-IV of FIG. 2, and FIG. 5 is a view taken along the line VV of FIG. FIG. 6 is a rear view of the engine holder 3 as viewed from the direction of arrow VI in FIG. 2.
[0029]
As shown in FIG. 3, a flat sealing surface 40 is formed on the upper surface of the engine holder 3 so as to be in intimate contact with the lower surface of the engine 2, and the mount holder 41 on which the upper engine mounts 24 are installed is provided substantially at the center of the upper surface. Is formed, and the mount holder 41 is closed by a mount lid 42 in a liquid-tight manner. A drive shaft insertion port 43 is formed in the mount holder 41 and the mount lid 42, and the drive shaft 18 is inserted through the drive shaft insertion port 43.
[0030]
Exhaust pipe connection ports 45 are formed on both left and right sides of the mount holder 41 so as to be aligned with an exhaust manifold (not shown) provided in the left and right banks of the engine 2, and surrounding the cooling water communicating with the engine 2. Jackets 46, 46 are formed.
[0031]
On the other hand, as shown in FIG. 4, on the lower surface of the engine holder 3, a seal surface 48 that is in close contact with the upper surface of the oil pan block 4 and a seal surface 49 that is in close contact with the upper surface of an exhaust block 76 described later are formed. Further, a release exhaust passage inlet 51 is formed at the center in the width direction so as to open downward so as to be surrounded by the seal surface 49, and a release exhaust passage 52 extends rearward from the release exhaust passage inlet 51. .
[0032]
The release exhaust passage 52 is formed inside the center portion of the engine holder 3 in the width direction, and has a rear end opening to the rear surface of the engine holder 3 (see FIG. 6). Further, inside the engine holder 3, a flush passage 53 (see FIG. 4) for cleaning the cooling water path and downflow passages 54 and 55 (FIGS. 2 and 6) for flowing the cooling water having cooled the engine 2 downward. ) Are formed horizontally, and these passages 53, 54, 55 also open to the rear surface of the engine holder 3.
[0033]
As shown in FIG. 2, the lower flow passage 55 is bent into an L-shape and is opened at the lower surface of the rearmost portion of the engine holder 3 as shown in FIGS. A downflow passage 56 that matches with 55 is formed.
[0034]
The upper and lower flow passages 54 and 55 formed inside the engine holder 3 become one continuous passage when the rear cover 58 is fixed to the rear surface of the engine holder 3. The rear cover 58 has a flush port 59 aligned with the flush passage 53 and a passage (not shown) for guiding the end of the release exhaust passage 52 to the final release chamber 61 inside the exhaust release cover 60 fixed to the rear surface of the oil pan block 4. Is formed. The final release chamber 61 is provided with a release exhaust outlet 62 that opens rearward.
[0035]
The flush port 59 is normally closed by a plug 63. However, when the outboard motor 1 is inspected and maintained, the plug 63 is removed and high-pressure water is injected into the flush port 59, thereby allowing each of the cooling water passages and the water jackets. Is performed (flushing).
[0036]
As shown in FIG. 5, the inside of the oil pan block 4 is partitioned by a partition 66 into two front and rear bottomed box-shaped rooms, a front room is an exhaust room 67, and a rear room is an oil room. The bread is 68. An exhaust pipe connection port 69 is formed at the bottom of the exhaust chamber 67, a cooling water passage connection port 70 is formed in front of the exhaust pipe connection port 69, and a sealing surface on the upper surface of the oil pan block 4 which is in close contact with the sealing surface 48 on the lower surface of the engine holder 3. A seal surface 72 is formed around the exhaust pipe connection port 69.
[0037]
Oil is stored in an oil pan 68, and an oil strainer 74 (see FIGS. 2 and 7) which is fixed to the lower surface of the engine holder 3 and hangs downward is immersed in the oil. 3 or an oil passage (not shown) formed on the engine 2 side. When the engine 2 operates, the oil pump is also driven, and the oil stored in the oil pan 68 is pumped up by the oil strainer 74 and supplied to each lubricating portion of the engine 2.
[0038]
As shown in FIG. 2, an exhaust block 76 formed separately from the oil pan block 4 is installed in the exhaust chamber 67. As shown in FIG. 7, the exhaust block 76 includes two left and right exhaust pipes 77, 77, a rising cooling water chamber 78, a release exhaust expansion chamber 79, an upper fixed flange 80, and a lower fixed flange 81. The inside of the exhaust pipes 77 is a main exhaust passage 82.
[0039]
The left and right exhaust pipes 77, 77 extend up and down, and the space therebetween is wide and narrow, and the cooling water chamber 78 is integrally provided between the exhaust pipes 77. The plane shape of the rising cooling water chamber 78 is substantially the same as the inner peripheral shape of the sealing surface 49 shown in FIG. 4, and the release exhaust expansion chamber 79 is surrounded by the rising cooling water chamber 78 and the partition 66, but the rising cooling water chamber 78. Not in communication with
[0040]
As shown in FIGS. 2 and 7, a round pipe-shaped cooling water rising passage 83 projecting downward from the rising cooling water chamber 78 is provided. The cooling water rising passage 83 passes through the lower fixing flange 81 together with the exhaust pipes 77, 77.
[0041]
The exhaust block 76 is fixed such that the upper fixing flange 80 is in close contact with the sealing surface 49 on the lower surface of the engine holder 3 and the lower fixing flange 81 is in close contact with the sealing surface 72 on the bottom of the exhaust chamber 67. The upper ends of the left and right exhaust pipes 77, 77 are closely inserted into the left and right exhaust pipe connection ports 45, 45 of the engine holder 3, and the lower ends of the exhaust pipes 77, 77 are connected to the exhaust pipe connection port 69 at the bottom of the exhaust chamber 67. The cooling water rising passage 83 is closely inserted, and the lower end of the cooling water rising passage 83 is densely inserted into the cooling water passage connection port 70.
[0042]
The release exhaust expansion chamber 79 of the exhaust block 76 is open at the top, and is aligned with the release exhaust passage inlet 51 on the lower surface of the engine holder 3. Further, as shown in FIG. 2, a release exhaust communication passage 85 communicating with an exhaust expansion chamber 84 inside the drive shaft housing 5 is provided at the bottom of the release exhaust expansion chamber 79.
[0043]
The exhaust gas of the engine 2 is exhausted from exhaust manifolds provided on the left and right cylinder heads 14 and exhaust pipe connection ports 45 of the engine holder 3 and main exhaust passages 82 of the exhaust block 76 (exhaust pipes 77, 77). ), Is guided to the exhaust expansion chamber 84, where it is expanded and silenced, and then discharged from the central portion of the propeller 21 into water through a discharge passage (not shown) formed around the propeller shaft 20.
[0044]
When the ship stops, the back pressure of the exhaust expansion chamber 84 increases, so that exhaust from the exhaust expansion chamber 84 becomes impossible. Therefore, the exhaust gas discharged to the exhaust expansion chamber 84 flows from the release exhaust communication passage 85 into the release exhaust expansion chamber 79, and after expanding there, flows from the release exhaust passage inlet 51 to the release exhaust passage 52, and further, the exhaust release cover. After flowing into the final release chamber 61 inside the chamber 60 and further expanding, it is discharged from the release exhaust outlet 62 to the outside.
[0045]
The space between the periphery of the exhaust block 76 and the inner wall of the exhaust chamber 67 serves as a cooling water storage unit 88. As will be described later, a part of the cooling water for cooling the engine 2 is passed through the cooling water storage unit 88 to be filled with the cooling water. The engine mounts 24, 24 (mount holder 41) provided on the engine holder 3 are arranged above the rising cooling water chamber 78 and the cooling water storing section 88.
[0046]
As shown in FIG. 2, a water pump 89 which is directly driven by the rotation of the drive shaft 18 is provided on the upper surface of the lower housing 6, and an upper end of a cooling water discharge pipe 90 extending upward from the water pump 89 is provided in the exhaust chamber 67. The cooling water discharged from the water pump 89 is connected from below to the cooling water passage connection port 70 at the bottom, and rises through the cooling water discharge pipe 90, the cooling water passage connection port 70, and the cooling water rise passage 83 to the cooling water chamber 78. The supplied cooling water chamber 78 is filled with the cooling water.
[0047]
As shown in FIG. 4, a pair of left and right cooling water discharge ports 91, 91 adjacent to the left and right exhaust pipe connection ports 45, 45 and located inside the frame of the sealing surface 49 are formed on the lower surface of the engine holder 3. The cooling water discharge ports 91 are connected to cooling water jackets 46 surrounding the exhaust pipe connection ports 45 (see FIG. 3). The cooling water that fills the rising cooling water chamber 78 flows through cooling water outlets 91, 91 and the cooling water jackets 46, 46 to a cooling water jacket (not shown) formed on the engine 2 side to cool each part of the engine 2. .
[0048]
The cooling water that has finished cooling the engine 2 flows down from a cooling water outlet (not shown) on the lower surface of the engine 2 to the upper surface at the rear of the engine holder 3, flows into the downstream passage 54 from a plurality of drains 92. It flows down from the outlet 93 through the outlet 56 into the exhaust expansion chamber 84 of the drive shaft housing 5. As shown in FIG. 2, the outlet 93 of the flow-down passage 56 is provided on the opposite side of the exhaust chamber 67 with respect to the oil pan 68, that is, on the rear side of the oil pan 68 in this case.
[0049]
As shown in FIG. 5, a relief valve 95 and a relief hole 96 are provided in the vicinity of the cooling water passage connection port 70. For example, when the water pressure rises before a thermostat (not shown) opens, the relief valve 95 opens, Part of the cooling water flowing through the cooling water passage connection port 70 flows into the cooling water storage 88 through the relief hole 96.
[0050]
Further, in the engine holder 3, cooling water inlets 97, 97 (see FIG. 4) communicating with cooling water jackets 46, 46 (see FIG. 3) surrounding the periphery of the exhaust pipe connection ports 45, 45 are formed. Further, notches 98, 98 are formed near the left and right sides of the exhaust chamber 67 as shown in FIG. For this reason, a part of the cooling water flowing through the cooling water jackets 46 flows into the cooling water storage section 88 through the cooling water inlets 97 and 97 and the notches 98 and 98.
[0051]
As described above, the cooling water flows into the cooling water storage unit 88 from the cooling water passage connection port 70 and the cooling water jackets 46, 46, and the inside of the cooling water storage unit 88 is filled with the cooling water. Since the circumference of the exhaust pipes 77, 77 of the exhaust block 76 rises and is surrounded by the cooling water chamber 78 and the cooling water storage part 88, the exhaust pipes 77, 77 are efficiently cooled and are insulated from the surroundings. Is made.
[0052]
As shown in FIG. 5, the cooling water accumulated in the cooling water storage unit 88 is supplied to the exhaust expansion chamber 84 from an overflow drain 99 provided to open at a high place in the exhaust chamber 67 (cooling water storage unit 88). Drained.
[0053]
In the outboard motor 1 configured as described above, since the inside of the oil pan block 4 is partitioned into the exhaust chamber 67 and the oil pan 68 by the partition wall 66, the main exhaust passages 82, 82 (the exhaust pipes 77, 77) are formed. The heat of the passing exhaust gas is insulated from the oil pan 68. Therefore, it is possible to prevent the oil temperature in the oil pan 68 from rising due to the exhaust heat.
[0054]
As shown in FIG. 2, the partition wall 66 includes a rear wall of the exhaust chamber 67 and a front wall of the oil pan 68, and an air layer intervenes therebetween. More effectively insulated.
[0055]
In addition, a cooling water reservoir 88 surrounding the main exhaust passages 82 and 82 is provided in the exhaust chamber 67, and a part of the engine cooling water is passed through the cooling water reservoir 88 to be filled with the cooling water. The heat of the exhaust gas passing through the main exhaust passages 82, 82 can be more effectively insulated from the peripheral portion such as the oil pan 68.
[0056]
Further, an exhaust chamber 67 is formed in a box shape with a bottom and an exhaust block 76 is provided therein. Main exhaust passages 82 and 82 are formed in the exhaust block 76, and a cooling water storage section 88 is formed between the exhaust block 76 and the periphery of the exhaust block 76. Since it is formed between the inner wall of the exhaust chamber 67 and the exhaust block 76 that forms the main exhaust passages 82, 82, the area around the exhaust block 76 is made compact to improve the assemblability of the outboard motor 1 and the hollow shape of the oil pan block 4. And the production can be facilitated.
[0057]
A rising cooling water chamber 78 and a release exhaust expansion chamber 79 are formed inside the exhaust block 76, and the rising cooling water chamber 78 is filled with cooling water. Therefore, cooling by the cooling water storage unit 88 and cooling by the rising cooling water chamber 78 are performed. The synergistic effect with the cooling allows the main exhaust passages 82, 82 and the release exhaust expansion chamber 79 to be cooled more efficiently, and also contributes greatly to downsizing around the exhaust block 76 and reducing the number of parts.
[0058]
Further, since the engine mounts 24, 24 are disposed above the cooling water storage section 88 and the cooling water chamber 78, heat of exhaust gas passing through the main exhaust passages 82, 82 is transmitted to the engine holder 3 to the engine mounts 24, 24. Therefore, it is possible to avoid early deterioration of the rubber engine mounts 24, 24 which dislike heat.
[0059]
Further, since the release exhaust passage 52 is formed inside the engine holder 3, the height of the release exhaust passage 52 can be made sufficiently high, so that even when the draft position of the hull is high, water is sprayed on the release exhaust passage 52. It becomes difficult, and the release exhaust can be performed smoothly.
[0060]
Further, since the outlet 93 of the downflow passage 56 through which the cooling water having cooled the engine 2 passes is provided on the opposite side of the exhaust chamber 67 with the oil pan 68 interposed therebetween, the outlet 93 between the main exhaust passages 82 and 82 and the outlet 93 is provided. An oil pan 68 is interposed therebetween, and as a result, the position where the cooling water that has finished cooling the engine 2 joins the exhaust gas discharged from the main exhaust passages 82, 82 is located below the oil pan 68, that is, in the release exhaust passage 52. The position is much lower than the height. For this reason, it is difficult for the exhaust gas flowing in the release exhaust passage 52 to entrain water, and it is difficult for water to be released from the release exhaust passage 52. As a result, the release of water from the release exhaust outlet 62 and the generation of noise can be prevented. Can be.
[0061]
Further, the release exhaust passage 52 extending to the rear of the engine holder 3 and the flush passage 53 for cleaning the cooling water passage are both opened rearward, so that the maintainability and layout of the outboard motor 1 are extremely good, and the outboard motor 1 is very good. The flushing operation can be easily performed even when the outer machine 1 is mounted on the hull by two aircrafts.
[0062]
In this embodiment, the engine 2 is a water-cooled four-cycle V-type six-cylinder engine. However, the present invention is not limited to this engine type, and is widely applied to outboard motors equipped with other types of four-stroke engines. can do.
[0063]
【The invention's effect】
As described above, according to the outboard motor of the present invention, it is possible to prevent the heat in the oil pan and the engine mount from being damaged by the heat of the exhaust gas, to make the release exhaust smooth, and to allow the release exhaust passage from the release exhaust passage. It is possible to prevent the release of water, to reduce the size of the engine and reduce the number of parts, and to improve the assemblability, maintainability, manufacturability and layout.
[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 a partial longitudinal sectional view of the outboard motor showing one embodiment of the present invention.
FIG. 3 is a top view of the engine holder as viewed in the direction of arrows III-III in FIG. 2;
FIG. 4 is a bottom view of the engine holder as viewed in the direction of arrows IV-IV in FIG. 2;
FIG. 5 is a top view of the oil pan block as viewed from the direction of arrows VV in FIG. 2;
FIG. 6 is a rear view of the engine holder as viewed in the direction of arrow VI in FIG. 2;
FIG. 7 is a perspective view of the engine holder and the exhaust block as viewed obliquely from below.
[Explanation of symbols]
REFERENCE SIGNS LIST 1 outboard motor 2 engine 3 engine holder 4 oil pan block 5 drive shaft housing 24 engine mount 52 release exhaust passage 53 flash passage 56 downflow passage 67 exhaust chamber 68 oil pan 76 exhaust block 78 rising cooling water chamber 79 release exhaust expansion chamber 82 Main exhaust passage 84 Exhaust expansion chamber 88 Cooling water reservoir 93 Exit of downflow passage

Claims (8)

An engine holder, an oil pan block, and a drive shaft housing are sequentially assembled at a lower portion of the engine, and the exhaust gas of the engine passes through a main exhaust passage provided inside the engine holder and the oil pan block, and is internally disposed in the drive shaft housing. In the outboard motor configured to be guided to the exhaust expansion chamber, the interior of the oil pan block is divided into a plurality of rooms, and one of the rooms is provided as the exhaust chamber, and the main exhaust passage is provided. An outboard motor characterized in that two rooms have oil pans. The interior of the oil pan block is divided into front and rear, the main exhaust passage is disposed with the front room as the exhaust chamber, the rear room is set as the oil pan, and the exhaust chamber surrounds the periphery of the main exhaust passage. An outboard motor provided with a water storage portion, wherein the cooling water storage portion is filled with cooling water through a part of engine cooling water. The exhaust chamber of the oil pan block is formed in a box shape with a bottom, an exhaust block formed separately from the oil pan block is installed in the exhaust chamber, and the main exhaust passage is formed inside the exhaust block, and The outboard motor according to claim 2, wherein the cooling water storage portion is provided between a periphery of the block and an inner wall of the exhaust chamber. The outboard motor according to claim 3, wherein a rising cooling water chamber and a release exhaust expansion chamber are formed inside the exhaust block, and the rising cooling water chamber is filled with cooling water. 5. The outboard motor according to claim 2, wherein an engine mount provided on the engine holder is disposed above at least one of the cooling water storage part and the rising cooling water chamber. 6. The outboard motor according to claim 1, wherein a release exhaust passage is formed inside the engine holder. 3. The outboard motor according to claim 1, wherein an outlet of a flow passage for cooling water after cooling the engine is provided on a side opposite to the exhaust chamber with the oil pan interposed therebetween. 4. The outboard motor according to claim 1, wherein a release exhaust passage and a flush passage for cleaning a cooling water passage are opened at a rear portion of the engine holder.

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